Update TransactionValidity_fr.properties

credit: stchoupi

.gitignore

@@ -26,3 +26,5 @@
 /run.pid
 /run.log
 /WindowsInstaller/Install Files/qortal.jar
+/*.7z
+/tmp

WindowsInstaller/Qortal.aip

@@ -17,10 +17,10 @@
     <ROW Property="Manufacturer" Value="Qortal"/>
     <ROW Property="MsiLogging" MultiBuildValue="DefaultBuild:vp"/>
     <ROW Property="NTP_GOOD" Value="false"/>
-    <ROW Property="ProductCode" Value="1033:{482E9390-1005-42FD-9F3F-E160E0E6FB19} 1049:{8FE09AC2-814B-42FC-9FCE-53D45A396529} 2052:{4FABD326-8345-438B-82B8-66C2DC3676E6} 2057:{7ECFFF43-DEC7-4B7F-BC88-260A10AF132A} " Type="16"/>
+    <ROW Property="ProductCode" Value="1033:{D45BD9F0-1D22-46A2-9990-8BB3598D8AD3} 1049:{21BCBDEC-4BF2-41D6-9426-E906042FD61F} 2052:{95F43BE3-58B4-4422-BCCF-D77F4BBFD7A4} 2057:{4C4D611E-3AF5-4216-952A-CA9E5EC32C19} " Type="16"/>
     <ROW Property="ProductLanguage" Value="2057"/>
     <ROW Property="ProductName" Value="Qortal"/>
-    <ROW Property="ProductVersion" Value="1.6.0" Type="32"/>
+    <ROW Property="ProductVersion" Value="2.1.2" Type="32"/>
     <ROW Property="RECONFIG_NTP" Value="true"/>
     <ROW Property="REMOVE_BLOCKCHAIN" Value="YES" Type="4"/>
     <ROW Property="REPAIR_BLOCKCHAIN" Value="YES" Type="4"/>
@@ -212,7 +212,7 @@
     <ROW Component="ADDITIONAL_LICENSE_INFO_71" ComponentId="{12A3ADBE-BB7A-496C-8869-410681E6232F}" Directory_="jdk.zipfs_Dir" Attributes="0" KeyPath="ADDITIONAL_LICENSE_INFO_71" Type="0"/>
     <ROW Component="ADDITIONAL_LICENSE_INFO_8" ComponentId="{D53AD95E-CF96-4999-80FC-5812277A7456}" Directory_="java.naming_Dir" Attributes="0" KeyPath="ADDITIONAL_LICENSE_INFO_8" Type="0"/>
     <ROW Component="ADDITIONAL_LICENSE_INFO_9" ComponentId="{6B7EA9B0-5D17-47A8-B78C-FACE86D15E01}" Directory_="java.net.http_Dir" Attributes="0" KeyPath="ADDITIONAL_LICENSE_INFO_9" Type="0"/>
-    <ROW Component="AI_CustomARPName" ComponentId="{7941AD6C-7C09-48E7-93ED-0340E0F52EC0}" Directory_="APPDIR" Attributes="260" KeyPath="DisplayName" Options="1"/>
+    <ROW Component="AI_CustomARPName" ComponentId="{5109CB00-40C0-499E-875B-9364F2075410}" Directory_="APPDIR" Attributes="260" KeyPath="DisplayName" Options="1"/>
     <ROW Component="AI_ExePath" ComponentId="{3644948D-AE0B-41BB-9FAF-A79E70490A08}" Directory_="APPDIR" Attributes="260" KeyPath="AI_ExePath"/>
     <ROW Component="APPDIR" ComponentId="{680DFDDE-3FB4-47A5-8FF5-934F576C6F91}" Directory_="APPDIR" Attributes="0"/>
     <ROW Component="AccessBridgeCallbacks.h" ComponentId="{288055D1-1062-47A3-AA44-5601B4E38AED}" Directory_="bridge_Dir" Attributes="0" KeyPath="AccessBridgeCallbacks.h" Type="0"/>

pom.xml

@@ -3,7 +3,7 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>org.qortal</groupId>
 	<artifactId>qortal</artifactId>
-	<version>1.6.0</version>
+	<version>2.1.2</version>
 	<packaging>jar</packaging>
 	<properties>
 		<skipTests>true</skipTests>
@@ -14,6 +14,9 @@
 		<ciyam-at.version>1.3.8</ciyam-at.version>
 		<commons-net.version>3.6</commons-net.version>
 		<commons-text.version>1.8</commons-text.version>
+		<commons-io.version>2.6</commons-io.version>
+		<commons-compress.version>1.21</commons-compress.version>
+		<xz.version>1.9</xz.version>
 		<dagger.version>1.2.2</dagger.version>
 		<guava.version>28.1-jre</guava.version>
 		<hsqldb.version>2.5.1</hsqldb.version>
@@ -449,6 +452,21 @@
 			<artifactId>commons-text</artifactId>
 			<version>${commons-text.version}</version>
 		</dependency>
+		<dependency>
+			<groupId>commons-io</groupId>
+			<artifactId>commons-io</artifactId>
+			<version>${commons-io.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.apache.commons</groupId>
+			<artifactId>commons-compress</artifactId>
+			<version>${commons-compress.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.tukaani</groupId>
+			<artifactId>xz</artifactId>
+			<version>${xz.version}</version>
+		</dependency>
 		<!--  For bitset/bitmap compression -->
 		<dependency>
 			<groupId>io.druid</groupId>

src/main/java/org/qortal/RepositoryMaintenance.java

@@ -1,6 +1,7 @@
 package org.qortal;
 
 import java.security.Security;
+import java.util.concurrent.TimeoutException;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -57,10 +58,10 @@ public class RepositoryMaintenance {
 
 		LOGGER.info("Starting repository periodic maintenance. This can take a while...");
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			repository.performPeriodicMaintenance();
+			repository.performPeriodicMaintenance(null);
 
 			LOGGER.info("Repository periodic maintenance completed");
-		} catch (DataException e) {
+		} catch (DataException | TimeoutException e) {
 			LOGGER.error("Repository periodic maintenance failed", e);
 		}
 

src/main/java/org/qortal/api/ApiExceptionFactory.java

@@ -16,4 +16,8 @@ public enum ApiExceptionFactory {
 		return createException(request, apiError, null);
 	}
 
+	public ApiException createCustomException(HttpServletRequest request, ApiError apiError, String message) {
+		return new ApiException(apiError.getStatus(), apiError.getCode(), message, null);
+	}
+
 }

src/main/java/org/qortal/api/ApiService.java

@@ -14,6 +14,8 @@ import java.security.SecureRandom;
 import javax.net.ssl.KeyManagerFactory;
 import javax.net.ssl.SSLContext;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.eclipse.jetty.http.HttpVersion;
 import org.eclipse.jetty.rewrite.handler.RedirectPatternRule;
 import org.eclipse.jetty.rewrite.handler.RewriteHandler;
@@ -50,6 +52,8 @@ import org.qortal.settings.Settings;
 
 public class ApiService {
 
+	private static final Logger LOGGER = LogManager.getLogger(ApiService.class);
+
 	private static ApiService instance;
 
 	private final ResourceConfig config;
@@ -203,6 +207,9 @@ public class ApiService {
 			context.addServlet(TradeBotWebSocket.class, "/websockets/crosschain/tradebot");
 			context.addServlet(PresenceWebSocket.class, "/websockets/presence");
 
+			// Warn about API security if needed
+			this.checkApiSecurity();
+
 			// Start server
 			this.server.start();
 		} catch (Exception e) {
@@ -222,4 +229,23 @@ public class ApiService {
 		this.server = null;
 	}
 
+	private void checkApiSecurity() {
+		// Warn about API security if needed
+		boolean allConnectionsAllowed = false;
+		if (Settings.getInstance().isApiKeyDisabled()) {
+			for (String pattern : Settings.getInstance().getApiWhitelist()) {
+				if (pattern.startsWith("0.0.0.0/") || pattern.startsWith("::/") || pattern.endsWith("/0")) {
+					allConnectionsAllowed = true;
+				}
+			}
+
+			if (allConnectionsAllowed) {
+				LOGGER.warn("Warning: API key validation is currently disabled, and the API whitelist " +
+						"is allowing all connections. This can be a security risk.");
+				LOGGER.warn("To fix, set the apiKeyDisabled setting to false, or allow only specific local " +
+						"IP addresses using the apiWhitelist setting.");
+			}
+		}
+	}
+
 }

src/main/java/org/qortal/api/Security.java

@@ -12,6 +12,11 @@ public abstract class Security {
 	public static final String API_KEY_HEADER = "X-API-KEY";
 
 	public static void checkApiCallAllowed(HttpServletRequest request) {
+		// If API key checking has been disabled, we will allow the request in all cases
+		boolean isApiKeyDisabled = Settings.getInstance().isApiKeyDisabled();
+		if (isApiKeyDisabled)
+			return;
+
 		String expectedApiKey = Settings.getInstance().getApiKey();
 		String passedApiKey = request.getHeader(API_KEY_HEADER);
 

src/main/java/org/qortal/api/model/ListRequest.java

@@ -7,12 +7,12 @@ import javax.xml.bind.annotation.XmlAccessorType;
 import java.util.List;
 
 @XmlAccessorType(XmlAccessType.FIELD)
-public class AddressListRequest {
+public class ListRequest {
 
-	@Schema(description = "A list of addresses")
-	public List<String> addresses;
+	@Schema(description = "A list of items")
+	public List<String> items;
 
-	public AddressListRequest() {
+	public ListRequest() {
 	}
 
 }

src/main/java/org/qortal/api/resource/AddressesResource.java

@@ -12,6 +12,7 @@ import io.swagger.v3.oas.annotations.tags.Tag;
 
 import java.math.BigDecimal;
 import java.util.ArrayList;
+import java.util.Comparator;
 import java.util.List;
 
 import javax.servlet.http.HttpServletRequest;
@@ -38,6 +39,7 @@ import org.qortal.crypto.Crypto;
 import org.qortal.data.account.AccountData;
 import org.qortal.data.account.RewardShareData;
 import org.qortal.data.network.OnlineAccountData;
+import org.qortal.data.network.OnlineAccountLevel;
 import org.qortal.data.transaction.PublicizeTransactionData;
 import org.qortal.data.transaction.RewardShareTransactionData;
 import org.qortal.data.transaction.TransactionData;
@@ -180,6 +182,66 @@ public class AddressesResource {
 		}
 	}
 
+	@GET
+	@Path("/online/levels")
+	@Operation(
+			summary = "Return currently 'online' accounts counts, grouped by level",
+			responses = {
+					@ApiResponse(
+							description = "online accounts",
+							content = @Content(mediaType = MediaType.APPLICATION_JSON, array = @ArraySchema(schema = @Schema(implementation = ApiOnlineAccount.class)))
+					)
+			}
+	)
+	@ApiErrors({ApiError.PUBLIC_KEY_NOT_FOUND, ApiError.REPOSITORY_ISSUE})
+	public List<OnlineAccountLevel> getOnlineAccountsByLevel() {
+		List<OnlineAccountData> onlineAccounts = Controller.getInstance().getOnlineAccounts();
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			List<OnlineAccountLevel> onlineAccountLevels = new ArrayList<>();
+
+			for (OnlineAccountData onlineAccountData : onlineAccounts) {
+				try {
+					final int minterLevel = Account.getRewardShareEffectiveMintingLevel(repository, onlineAccountData.getPublicKey());
+
+					OnlineAccountLevel onlineAccountLevel = onlineAccountLevels.stream()
+							.filter(a -> a.getLevel() == minterLevel)
+							.findFirst().orElse(null);
+
+					// Note: I don't think we can use the level as the List index here because there will be gaps.
+					// So we are forced to manually look up the existing item each time.
+					// There's probably a nice shorthand java way of doing this, but this approach gets the same result.
+
+					if (onlineAccountLevel == null) {
+						// No entry exists for this level yet, so create one
+						onlineAccountLevel = new OnlineAccountLevel(minterLevel, 1);
+						onlineAccountLevels.add(onlineAccountLevel);
+					}
+					else {
+						// Already exists - so increment the count
+						int existingCount = onlineAccountLevel.getCount();
+						onlineAccountLevel.setCount(++existingCount);
+
+						// Then replace the existing item
+						int index = onlineAccountLevels.indexOf(onlineAccountLevel);
+						onlineAccountLevels.set(index, onlineAccountLevel);
+					}
+
+				} catch (DataException e) {
+					continue;
+				}
+			}
+
+			// Sort by level
+			onlineAccountLevels.sort(Comparator.comparingInt(OnlineAccountLevel::getLevel));
+
+			return onlineAccountLevels;
+
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
 	@GET
 	@Path("/balance/{address}")
 	@Operation(

src/main/java/org/qortal/api/resource/AdminResource.java

@@ -22,6 +22,7 @@ import java.time.OffsetDateTime;
 import java.time.ZoneOffset;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.stream.Collectors;
 
@@ -35,6 +36,7 @@ import javax.ws.rs.core.Context;
 import javax.ws.rs.core.MediaType;
 
 import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.core.LoggerContext;
 import org.apache.logging.log4j.core.appender.RollingFileAppender;
 import org.qortal.account.Account;
@@ -67,6 +69,8 @@ import com.google.common.collect.Lists;
 @Tag(name = "Admin")
 public class AdminResource {
 
+	private static final Logger LOGGER = LogManager.getLogger(AdminResource.class);
+
 	private static final int MAX_LOG_LINES = 500;
 
 	@Context
@@ -459,6 +463,23 @@ public class AdminResource {
 			if (targetHeight <= 0 || targetHeight > Controller.getInstance().getChainHeight())
 				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_HEIGHT);
 
+			// Make sure we're not orphaning as far back as the archived blocks
+			// FUTURE: we could support this by first importing earlier blocks from the archive
+			if (Settings.getInstance().isTopOnly() ||
+				Settings.getInstance().isArchiveEnabled()) {
+
+				try (final Repository repository = RepositoryManager.getRepository()) {
+					// Find the first unarchived block
+					int oldestBlock = repository.getBlockArchiveRepository().getBlockArchiveHeight();
+					// Add some extra blocks just in case we're currently archiving/pruning
+					oldestBlock += 100;
+					if (targetHeight <= oldestBlock) {
+						LOGGER.info("Unable to orphan beyond block {} because it is archived", oldestBlock);
+						throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_HEIGHT);
+					}
+				}
+			}
+
 			if (BlockChain.orphan(targetHeight))
 				return "true";
 			else
@@ -553,13 +574,13 @@ public class AdminResource {
 	@Path("/repository/data")
 	@Operation(
 		summary = "Import data into repository.",
-		description = "Imports data from file on local machine. Filename is forced to 'import.json' if apiKey is not set.",
+		description = "Imports data from file on local machine. Filename is forced to 'qortal-backup/TradeBotStates.json' if apiKey is not set.",
 		requestBody = @RequestBody(
 			required = true,
 			content = @Content(
 				mediaType = MediaType.TEXT_PLAIN,
 				schema = @Schema(
-					type = "string", example = "MintingAccounts.script"
+					type = "string", example = "qortal-backup/TradeBotStates.json"
 				)
 			)
 		),
@@ -577,7 +598,7 @@ public class AdminResource {
 
 		// Hard-coded because it's too dangerous to allow user-supplied filenames in weaker security contexts
 		if (Settings.getInstance().getApiKey() == null)
-			filename = "import.json";
+			filename = "qortal-backup/TradeBotStates.json";
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			ReentrantLock blockchainLock = Controller.getInstance().getBlockchainLock();
@@ -589,6 +610,10 @@ public class AdminResource {
 				repository.saveChanges();
 
 				return "true";
+
+			} catch (IOException e) {
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA, e);
+
 			} finally {
 				blockchainLock.unlock();
 			}
@@ -644,14 +669,16 @@ public class AdminResource {
 			blockchainLock.lockInterruptibly();
 
 			try {
-				repository.backup(true);
+				// Timeout if the database isn't ready for backing up after 60 seconds
+				long timeout = 60 * 1000L;
+				repository.backup(true, "backup", timeout);
 				repository.saveChanges();
 
 				return "true";
 			} finally {
 				blockchainLock.unlock();
 			}
-		} catch (InterruptedException e) {
+		} catch (InterruptedException | TimeoutException e) {
 			// We couldn't lock blockchain to perform backup
 			return "false";
 		} catch (DataException e) {
@@ -676,13 +703,15 @@ public class AdminResource {
 			blockchainLock.lockInterruptibly();
 
 			try {
-				repository.performPeriodicMaintenance();
+				// Timeout if the database isn't ready to start after 60 seconds
+				long timeout = 60 * 1000L;
+				repository.performPeriodicMaintenance(timeout);
 			} finally {
 				blockchainLock.unlock();
 			}
 		} catch (InterruptedException e) {
 			// No big deal
-		} catch (DataException e) {
+		} catch (DataException | TimeoutException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
 	}

src/main/java/org/qortal/api/resource/BlocksResource.java

@@ -15,6 +15,8 @@ import java.math.BigDecimal;
 import java.math.BigInteger;
 import java.math.RoundingMode;
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
 import java.util.List;
 
 import javax.servlet.http.HttpServletRequest;
@@ -33,11 +35,13 @@ import org.qortal.api.ApiExceptionFactory;
 import org.qortal.api.model.BlockMintingInfo;
 import org.qortal.api.model.BlockSignerSummary;
 import org.qortal.block.Block;
+import org.qortal.controller.Controller;
 import org.qortal.crypto.Crypto;
 import org.qortal.data.account.AccountData;
 import org.qortal.data.block.BlockData;
 import org.qortal.data.block.BlockSummaryData;
 import org.qortal.data.transaction.TransactionData;
+import org.qortal.repository.BlockArchiveReader;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
 import org.qortal.repository.RepositoryManager;
@@ -71,7 +75,8 @@ public class BlocksResource {
 	@ApiErrors({
 		ApiError.INVALID_SIGNATURE, ApiError.BLOCK_UNKNOWN, ApiError.REPOSITORY_ISSUE
 	})
-	public BlockData getBlock(@PathParam("signature") String signature58) {
+	public BlockData getBlock(@PathParam("signature") String signature58,
+							  @QueryParam("includeOnlineSignatures") Boolean includeOnlineSignatures) {
 		// Decode signature
 		byte[] signature;
 		try {
@@ -81,11 +86,25 @@ public class BlocksResource {
 		}
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
+		    // Check the database first
 			BlockData blockData = repository.getBlockRepository().fromSignature(signature);
-			if (blockData == null)
-				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
+			if (blockData != null) {
+				if (includeOnlineSignatures == null || includeOnlineSignatures == false) {
+					blockData.setOnlineAccountsSignatures(null);
+				}
+				return blockData;
+			}
 
-			return blockData;
+            // Not found, so try the block archive
+			blockData = repository.getBlockArchiveRepository().fromSignature(signature);
+			if (blockData != null) {
+				if (includeOnlineSignatures == null || includeOnlineSignatures == false) {
+					blockData.setOnlineAccountsSignatures(null);
+				}
+				return blockData;
+			}
+
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -116,16 +135,24 @@ public class BlocksResource {
 		}
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
+
+            // Check the database first
 			BlockData blockData = repository.getBlockRepository().fromSignature(signature);
-			if (blockData == null)
-				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
+			if (blockData != null) {
+                Block block = new Block(repository, blockData);
+                ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+                bytes.write(Ints.toByteArray(block.getBlockData().getHeight()));
+                bytes.write(BlockTransformer.toBytes(block));
+                return Base58.encode(bytes.toByteArray());
+            }
 
-			Block block = new Block(repository, blockData);
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-			bytes.write(Ints.toByteArray(block.getBlockData().getHeight()));
-			bytes.write(BlockTransformer.toBytes(block));
-			return Base58.encode(bytes.toByteArray());
+            // Not found, so try the block archive
+            byte[] bytes = BlockArchiveReader.getInstance().fetchSerializedBlockBytesForSignature(signature, false, repository);
+            if (bytes != null) {
+                return Base58.encode(bytes);
+            }
 
+            throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
 		} catch (TransformationException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_DATA, e);
 		} catch (DataException | IOException e) {
@@ -170,8 +197,12 @@ public class BlocksResource {
 		}
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			if (repository.getBlockRepository().getHeightFromSignature(signature) == 0)
+		    // Check if the block exists in either the database or archive
+			if (repository.getBlockRepository().getHeightFromSignature(signature) == 0 &&
+					repository.getBlockArchiveRepository().getHeightFromSignature(signature) == 0) {
+				// Not found in either the database or archive
 				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
+            }
 
 			return repository.getBlockRepository().getTransactionsFromSignature(signature, limit, offset, reverse);
 		} catch (DataException e) {
@@ -200,7 +231,19 @@ public class BlocksResource {
 	})
 	public BlockData getFirstBlock() {
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			return repository.getBlockRepository().fromHeight(1);
+			// Check the database first
+			BlockData blockData = repository.getBlockRepository().fromHeight(1);
+			if (blockData != null) {
+				return blockData;
+			}
+
+			// Try the archive
+			blockData = repository.getBlockArchiveRepository().fromHeight(1);
+			if (blockData != null) {
+				return blockData;
+			}
+
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -262,17 +305,28 @@ public class BlocksResource {
 		}
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
+			BlockData childBlockData = null;
+
+			// Check if block exists in database
 			BlockData blockData = repository.getBlockRepository().fromSignature(signature);
+			if (blockData != null) {
+				return repository.getBlockRepository().fromReference(signature);
+			}
 
-			// Check block exists
-			if (blockData == null)
-				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
-
-			BlockData childBlockData = repository.getBlockRepository().fromReference(signature);
+			// Not found, so try the archive
+			// This also checks that the parent block exists
+			// It will return null if either the parent or child don't exit
+			childBlockData = repository.getBlockArchiveRepository().fromReference(signature);
 
 			// Check child block exists
-			if (childBlockData == null)
+			if (childBlockData == null) {
 				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
+			}
+
+			// Check child block's reference matches the supplied signature
+			if (!Arrays.equals(childBlockData.getReference(), signature)) {
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
+			}
 
 			return childBlockData;
 		} catch (DataException e) {
@@ -338,13 +392,20 @@ public class BlocksResource {
 		}
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
+			// Firstly check the database
 			BlockData blockData = repository.getBlockRepository().fromSignature(signature);
+			if (blockData != null) {
+				return blockData.getHeight();
+			}
 
-			// Check block exists
-			if (blockData == null)
-				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
+			// Not found, so try the archive
+			blockData = repository.getBlockArchiveRepository().fromSignature(signature);
+			if (blockData != null) {
+				return blockData.getHeight();
+			}
+
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
 
-			return blockData.getHeight();
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -369,13 +430,29 @@ public class BlocksResource {
 	@ApiErrors({
 		ApiError.BLOCK_UNKNOWN, ApiError.REPOSITORY_ISSUE
 	})
-	public BlockData getByHeight(@PathParam("height") int height) {
+	public BlockData getByHeight(@PathParam("height") int height,
+								 @QueryParam("includeOnlineSignatures") Boolean includeOnlineSignatures) {
 		try (final Repository repository = RepositoryManager.getRepository()) {
+			// Firstly check the database
 			BlockData blockData = repository.getBlockRepository().fromHeight(height);
-			if (blockData == null)
-				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
+			if (blockData != null) {
+				if (includeOnlineSignatures == null || includeOnlineSignatures == false) {
+					blockData.setOnlineAccountsSignatures(null);
+				}
+				return blockData;
+			}
+
+			// Not found, so try the archive
+			blockData = repository.getBlockArchiveRepository().fromHeight(height);
+			if (blockData != null) {
+				if (includeOnlineSignatures == null || includeOnlineSignatures == false) {
+					blockData.setOnlineAccountsSignatures(null);
+				}
+				return blockData;
+			}
+
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
 
-			return blockData;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -402,12 +479,31 @@ public class BlocksResource {
 	})
 	public BlockMintingInfo getBlockMintingInfoByHeight(@PathParam("height") int height) {
 		try (final Repository repository = RepositoryManager.getRepository()) {
+			// Try the database
 			BlockData blockData = repository.getBlockRepository().fromHeight(height);
-			if (blockData == null)
-				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
+			if (blockData == null) {
+
+				// Not found, so try the archive
+				blockData = repository.getBlockArchiveRepository().fromHeight(height);
+				if (blockData == null) {
+
+					// Still not found
+					throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
+				}
+			}
 
 			Block block = new Block(repository, blockData);
 			BlockData parentBlockData = repository.getBlockRepository().fromSignature(blockData.getReference());
+			if (parentBlockData == null) {
+				// Parent block not found - try the archive
+				parentBlockData = repository.getBlockArchiveRepository().fromSignature(blockData.getReference());
+				if (parentBlockData == null) {
+
+					// Still not found
+					throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
+				}
+			}
+
 			int minterLevel = Account.getRewardShareEffectiveMintingLevel(repository, blockData.getMinterPublicKey());
 			if (minterLevel == 0)
 				// This may be unavailable when requesting a trimmed block
@@ -454,13 +550,26 @@ public class BlocksResource {
 	})
 	public BlockData getByTimestamp(@PathParam("timestamp") long timestamp) {
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			int height = repository.getBlockRepository().getHeightFromTimestamp(timestamp);
-			if (height == 0)
-				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
+			BlockData blockData = null;
 
-			BlockData blockData = repository.getBlockRepository().fromHeight(height);
-			if (blockData == null)
+			// Try the Blocks table
+			int height = repository.getBlockRepository().getHeightFromTimestamp(timestamp);
+			if (height > 0) {
+				// Found match in Blocks table
+				return repository.getBlockRepository().fromHeight(height);
+			}
+
+			// Not found in Blocks table, so try the archive
+			height = repository.getBlockArchiveRepository().getHeightFromTimestamp(timestamp);
+			if (height > 0) {
+				// Found match in archive
+				blockData = repository.getBlockArchiveRepository().fromHeight(height);
+			}
+
+			// Ensure block exists
+			if (blockData == null) {
 				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
+			}
 
 			return blockData;
 		} catch (DataException e) {
@@ -497,9 +606,14 @@ public class BlocksResource {
 
 			for (/* count already set */; count > 0; --count, ++height) {
 				BlockData blockData = repository.getBlockRepository().fromHeight(height);
-				if (blockData == null)
-					// Run out of blocks!
-					break;
+				if (blockData == null) {
+					// Not found - try the archive
+					blockData = repository.getBlockArchiveRepository().fromHeight(height);
+					if (blockData == null) {
+						// Run out of blocks!
+						break;
+					}
+				}
 
 				blocks.add(blockData);
 			}
@@ -544,7 +658,29 @@ public class BlocksResource {
 			if (accountData == null || accountData.getPublicKey() == null)
 				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.PUBLIC_KEY_NOT_FOUND);
 
-			return repository.getBlockRepository().getBlockSummariesBySigner(accountData.getPublicKey(), limit, offset, reverse);
+
+			List<BlockSummaryData> summaries = repository.getBlockRepository()
+					.getBlockSummariesBySigner(accountData.getPublicKey(), limit, offset, reverse);
+
+			// Add any from the archive
+			List<BlockSummaryData> archivedSummaries = repository.getBlockArchiveRepository()
+					.getBlockSummariesBySigner(accountData.getPublicKey(), limit, offset, reverse);
+			if (archivedSummaries != null && !archivedSummaries.isEmpty()) {
+				summaries.addAll(archivedSummaries);
+			}
+			else {
+				summaries = archivedSummaries;
+			}
+
+			// Sort the results (because they may have been obtained from two places)
+			if (reverse != null && reverse) {
+				summaries.sort((s1, s2) -> Integer.valueOf(s2.getHeight()).compareTo(Integer.valueOf(s1.getHeight())));
+			}
+			else {
+				summaries.sort(Comparator.comparing(s -> Integer.valueOf(s.getHeight())));
+			}
+
+			return summaries;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -580,7 +716,8 @@ public class BlocksResource {
 				if (!Crypto.isValidAddress(address))
 					throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
 
-			return repository.getBlockRepository().getBlockSigners(addresses, limit, offset, reverse);
+			// This method pulls data from both Blocks and BlockArchive, so no need to query serparately
+			return repository.getBlockArchiveRepository().getBlockSigners(addresses, limit, offset, reverse);
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -620,7 +757,76 @@ public class BlocksResource {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			return repository.getBlockRepository().getBlockSummaries(startHeight, endHeight, count);
+
+			/*
+			 * start	end		count		result
+			 * 10		40		null		blocks 10 to 39 (excludes end block, ignore count)
+			 *
+			 * null		null	null		blocks 1 to 50 (assume count=50, maybe start=1)
+			 * 30		null	null		blocks 30 to 79 (assume count=50)
+			 * 30		null	10			blocks 30 to 39
+			 *
+			 * null		null	50			last 50 blocks? so if max(blocks.height) is 200, then blocks 151 to 200
+			 * null		200		null		blocks 150 to 199 (excludes end block, assume count=50)
+			 * null		200		10			blocks 190 to 199 (excludes end block)
+			 */
+
+			List<BlockSummaryData> blockSummaries = new ArrayList<>();
+
+			// Use the latest X blocks if only a count is specified
+			if (startHeight == null && endHeight == null && count != null) {
+				BlockData chainTip = repository.getBlockRepository().getLastBlock();
+				startHeight = chainTip.getHeight() - count;
+				endHeight = chainTip.getHeight();
+			}
+
+			// ... otherwise default the start height to 1
+			if (startHeight == null && endHeight == null) {
+				startHeight = 1;
+			}
+
+			// Default the count to 50
+			if (count == null) {
+				count = 50;
+			}
+
+			// If both a start and end height exist, ignore the count
+			if (startHeight != null && endHeight != null) {
+				if (startHeight > 0 && endHeight > 0) {
+					count = Integer.MAX_VALUE;
+				}
+			}
+
+			// Derive start height from end height if missing
+			if (startHeight == null || startHeight == 0) {
+				if (endHeight != null && endHeight > 0) {
+					if (count != null) {
+						startHeight = endHeight - count;
+					}
+				}
+			}
+
+			for (/* count already set */; count > 0; --count, ++startHeight) {
+				if (endHeight != null && startHeight >= endHeight) {
+					break;
+				}
+				BlockData blockData = repository.getBlockRepository().fromHeight(startHeight);
+				if (blockData == null) {
+					// Not found - try the archive
+					blockData = repository.getBlockArchiveRepository().fromHeight(startHeight);
+					if (blockData == null) {
+						// Run out of blocks!
+						break;
+					}
+				}
+
+				if (blockData != null) {
+					BlockSummaryData blockSummaryData = new BlockSummaryData(blockData);
+					blockSummaries.add(blockSummaryData);
+				}
+			}
+
+			return blockSummaries;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}

src/main/java/org/qortal/api/resource/BootstrapResource.java

@@ -0,0 +1,92 @@
+package org.qortal.api.resource;
+
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.media.Content;
+import io.swagger.v3.oas.annotations.media.Schema;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.api.ApiError;
+import org.qortal.api.ApiExceptionFactory;
+import org.qortal.api.Security;
+import org.qortal.repository.Bootstrap;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.ws.rs.*;
+import javax.ws.rs.core.Context;
+import javax.ws.rs.core.MediaType;
+import java.io.IOException;
+
+
+@Path("/bootstrap")
+@Tag(name = "Bootstrap")
+public class BootstrapResource {
+
+	private static final Logger LOGGER = LogManager.getLogger(BootstrapResource.class);
+
+	@Context
+	HttpServletRequest request;
+
+	@POST
+	@Path("/create")
+	@Operation(
+		summary = "Create bootstrap",
+		description = "Builds a bootstrap file for distribution",
+		responses = {
+			@ApiResponse(
+				description = "path to file on success, an exception on failure",
+				content = @Content(mediaType = MediaType.TEXT_PLAIN, schema = @Schema(type = "string"))
+			)
+		}
+	)
+	public String createBootstrap() {
+		Security.checkApiCallAllowed(request);
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+
+			Bootstrap bootstrap = new Bootstrap(repository);
+			try {
+				bootstrap.checkRepositoryState();
+			} catch (DataException e) {
+				LOGGER.info("Not ready to create bootstrap: {}", e.getMessage());
+				throw ApiExceptionFactory.INSTANCE.createCustomException(request, ApiError.REPOSITORY_ISSUE, e.getMessage());
+			}
+			bootstrap.validateBlockchain();
+			return bootstrap.create();
+
+		} catch (DataException | InterruptedException | IOException e) {
+			LOGGER.info("Unable to create bootstrap", e);
+			throw ApiExceptionFactory.INSTANCE.createCustomException(request, ApiError.REPOSITORY_ISSUE, e.getMessage());
+		}
+	}
+
+	@GET
+	@Path("/validate")
+	@Operation(
+			summary = "Validate blockchain",
+			description = "Useful to check database integrity prior to creating or after installing a bootstrap. " +
+					"This process is intensive and can take over an hour to run.",
+			responses = {
+					@ApiResponse(
+							description = "true if valid, false if invalid",
+							content = @Content(mediaType = MediaType.TEXT_PLAIN, schema = @Schema(type = "boolean"))
+					)
+			}
+	)
+	public boolean validateBootstrap() {
+		Security.checkApiCallAllowed(request);
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+
+			Bootstrap bootstrap = new Bootstrap(repository);
+			return bootstrap.validateCompleteBlockchain();
+
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE);
+		}
+	}
+}

src/main/java/org/qortal/api/resource/CrossChainHtlcResource.java

@@ -11,6 +11,7 @@ import java.util.List;
 
 import javax.servlet.http.HttpServletRequest;
 import javax.ws.rs.GET;
+import javax.ws.rs.POST;
 import javax.ws.rs.Path;
 import javax.ws.rs.PathParam;
 import javax.ws.rs.core.Context;
@@ -173,7 +174,7 @@ public class CrossChainHtlcResource {
 		}
 	}
 
-	@GET
+	@POST
 	@Path("/redeem/{ataddress}")
 	@Operation(
 			summary = "Redeems HTLC associated with supplied AT",
@@ -231,7 +232,7 @@ public class CrossChainHtlcResource {
 		}
 	}
 
-	@GET
+	@POST
 	@Path("/redeemAll")
 	@Operation(
 			summary = "Redeems HTLC for all applicable ATs in tradebot data",
@@ -415,7 +416,7 @@ public class CrossChainHtlcResource {
 		return false;
 	}
 
-	@GET
+	@POST
 	@Path("/refund/{ataddress}")
 	@Operation(
 			summary = "Refunds HTLC associated with supplied AT",
@@ -463,7 +464,7 @@ public class CrossChainHtlcResource {
 	}
 
 
-	@GET
+	@POST
 	@Path("/refundAll")
 	@Operation(
 			summary = "Refunds HTLC for all applicable ATs in tradebot data",
@@ -478,8 +479,6 @@ public class CrossChainHtlcResource {
 	)
 	@ApiErrors({ApiError.INVALID_CRITERIA, ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN})
 	public boolean refundAllHtlc() {
-		Security.checkApiCallAllowed(request);
-
 		Security.checkApiCallAllowed(request);
 		boolean success = false;
 
@@ -568,6 +567,13 @@ public class CrossChainHtlcResource {
 			if (crossChainTradeData == null)
 				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
 
+			// If the AT is "finished" then it will have a zero balance
+			// In these cases we should avoid HTLC refunds if tbe QORT haven't been returned to the seller
+			if (atData.getIsFinished() && crossChainTradeData.mode != AcctMode.REFUNDED && crossChainTradeData.mode != AcctMode.CANCELLED) {
+				LOGGER.info(String.format("Skipping AT %s because the QORT has already been redemed", atAddress));
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+			}
+
 			List<TradeBotData> allTradeBotData = repository.getCrossChainRepository().getAllTradeBotData();
 			TradeBotData tradeBotData = allTradeBotData.stream().filter(tradeBotDataItem -> tradeBotDataItem.getAtAddress().equals(atAddress)).findFirst().orElse(null);
 			if (tradeBotData == null)

src/main/java/org/qortal/api/resource/CrossChainResource.java

@@ -1,5 +1,6 @@
 package org.qortal.api.resource;
 
+import com.google.common.primitives.Longs;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
 import io.swagger.v3.oas.annotations.media.ArraySchema;
@@ -10,12 +11,7 @@ import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import io.swagger.v3.oas.annotations.security.SecurityRequirement;
 import io.swagger.v3.oas.annotations.tags.Tag;
 
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
-import java.util.Map;
-import java.util.Random;
+import java.util.*;
 import java.util.function.Supplier;
 
 import javax.servlet.http.HttpServletRequest;
@@ -95,7 +91,7 @@ public class CrossChainResource {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
 
 		final boolean isExecutable = true;
-		List<CrossChainTradeData> crossChainTradesData = new ArrayList<>();
+		List<CrossChainTradeData> crossChainTrades = new ArrayList<>();
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			Map<ByteArray, Supplier<ACCT>> acctsByCodeHash = SupportedBlockchain.getFilteredAcctMap(foreignBlockchain);
@@ -108,11 +104,27 @@ public class CrossChainResource {
 
 				for (ATData atData : atsData) {
 					CrossChainTradeData crossChainTradeData = acct.populateTradeData(repository, atData);
-					crossChainTradesData.add(crossChainTradeData);
+					if (crossChainTradeData.mode == AcctMode.OFFERING) {
+						crossChainTrades.add(crossChainTradeData);
+					}
 				}
 			}
 
-			return crossChainTradesData;
+			// Sort the trades by timestamp
+			if (reverse != null && reverse) {
+				crossChainTrades.sort((a, b) -> Longs.compare(b.creationTimestamp, a.creationTimestamp));
+			}
+			else {
+				crossChainTrades.sort((a, b) -> Longs.compare(a.creationTimestamp, b.creationTimestamp));
+			}
+
+			if (limit != null && limit > 0) {
+				// Make sure to not return more than the limit
+				int upperLimit = Math.min(limit, crossChainTrades.size());
+				crossChainTrades = crossChainTrades.subList(0, upperLimit);
+			}
+
+			return crossChainTrades;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -195,6 +207,11 @@ public class CrossChainResource {
 
 			if (minimumTimestamp != null) {
 				minimumFinalHeight = repository.getBlockRepository().getHeightFromTimestamp(minimumTimestamp);
+				// If not found in the block repository it will return either 0 or 1
+				if (minimumFinalHeight == 0 || minimumFinalHeight == 1) {
+					// Try the archive
+					minimumFinalHeight = repository.getBlockArchiveRepository().getHeightFromTimestamp(minimumTimestamp);
+				}
 
 				if (minimumFinalHeight == 0)
 					// We don't have any blocks since minimumTimestamp, let alone trades, so nothing to return
@@ -222,12 +239,30 @@ public class CrossChainResource {
 
 					// We also need block timestamp for use as trade timestamp
 					long timestamp = repository.getBlockRepository().getTimestampFromHeight(atState.getHeight());
+					if (timestamp == 0) {
+						// Try the archive
+						timestamp = repository.getBlockArchiveRepository().getTimestampFromHeight(atState.getHeight());
+					}
 
 					CrossChainTradeSummary crossChainTradeSummary = new CrossChainTradeSummary(crossChainTradeData, timestamp);
 					crossChainTrades.add(crossChainTradeSummary);
 				}
 			}
 
+			// Sort the trades by timestamp
+			if (reverse != null && reverse) {
+				crossChainTrades.sort((a, b) -> Longs.compare(b.getTradeTimestamp(), a.getTradeTimestamp()));
+			}
+			else {
+				crossChainTrades.sort((a, b) -> Longs.compare(a.getTradeTimestamp(), b.getTradeTimestamp()));
+			}
+
+			if (limit != null && limit > 0) {
+				// Make sure to not return more than the limit
+				int upperLimit = Math.min(limit, crossChainTrades.size());
+				crossChainTrades = crossChainTrades.subList(0, upperLimit);
+			}
+
 			return crossChainTrades;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
@@ -260,7 +295,12 @@ public class CrossChainResource {
 					description = "Maximum number of trades to include in price calculation",
 					example = "10",
 					schema = @Schema(type = "integer", defaultValue = "10")
-			) @QueryParam("maxtrades") Integer maxtrades) {
+			) @QueryParam("maxtrades") Integer maxtrades,
+			@Parameter(
+					description = "Display price in terms of foreign currency per unit QORT",
+					example = "false",
+					schema = @Schema(type = "boolean", defaultValue = "false")
+			) @QueryParam("inverse") Boolean inverse) {
 		// foreignBlockchain is required
 		if (foreignBlockchain == null)
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
@@ -270,6 +310,7 @@ public class CrossChainResource {
 		int maximumCount = maxtrades != null ? maxtrades : 10;
 		long minimumPeriod = 4 * 60 * 60 * 1000L; // ms
 		Boolean isFinished = Boolean.TRUE;
+		boolean useInversePrice = (inverse != null && inverse == true);
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			Map<ByteArray, Supplier<ACCT>> acctsByCodeHash = SupportedBlockchain.getFilteredAcctMap(foreignBlockchain);
@@ -277,6 +318,9 @@ public class CrossChainResource {
 			long totalForeign = 0;
 			long totalQort = 0;
 
+			Map<Long, CrossChainTradeData> reverseSortedTradeData = new TreeMap<>(Collections.reverseOrder());
+
+			// Collect recent AT states for each ACCT version
 			for (Map.Entry<ByteArray, Supplier<ACCT>> acctInfo : acctsByCodeHash.entrySet()) {
 				byte[] codeHash = acctInfo.getKey().value;
 				ACCT acct = acctInfo.getValue().get();
@@ -285,13 +329,38 @@ public class CrossChainResource {
 						isFinished, acct.getModeByteOffset(), (long) AcctMode.REDEEMED.value, minimumCount, maximumCount, minimumPeriod);
 
 				for (ATStateData atState : atStates) {
+					// We also need block timestamp for use as trade timestamp
+					long timestamp = repository.getBlockRepository().getTimestampFromHeight(atState.getHeight());
+					if (timestamp == 0) {
+						// Try the archive
+						timestamp = repository.getBlockArchiveRepository().getTimestampFromHeight(atState.getHeight());
+					}
+
 					CrossChainTradeData crossChainTradeData = acct.populateTradeData(repository, atState);
-					totalForeign += crossChainTradeData.expectedForeignAmount;
-					totalQort += crossChainTradeData.qortAmount;
+					reverseSortedTradeData.put(timestamp, crossChainTradeData);
 				}
 			}
 
-			return Amounts.scaledDivide(totalQort, totalForeign);
+			// Loop through the sorted map and calculate the average price
+			// Also remove elements beyond the maxtrades limit
+			Set set = reverseSortedTradeData.entrySet();
+			Iterator i = set.iterator();
+			int index = 0;
+			while (i.hasNext()) {
+				Map.Entry tradeDataMap = (Map.Entry)i.next();
+				CrossChainTradeData crossChainTradeData = (CrossChainTradeData) tradeDataMap.getValue();
+
+				if (maxtrades != null && index >= maxtrades) {
+					// We've reached the limit
+					break;
+				}
+
+				totalForeign += crossChainTradeData.expectedForeignAmount;
+				totalQort += crossChainTradeData.qortAmount;
+				index++;
+			}
+
+			return useInversePrice ? Amounts.scaledDivide(totalForeign, totalQort) : Amounts.scaledDivide(totalQort, totalForeign);
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -421,4 +490,4 @@ public class CrossChainResource {
 		}
 	}
 
-}
+}

src/main/java/org/qortal/api/resource/CrossChainTradeBotResource.java

@@ -30,6 +30,7 @@ import org.qortal.api.Security;
 import org.qortal.api.model.crosschain.TradeBotCreateRequest;
 import org.qortal.api.model.crosschain.TradeBotRespondRequest;
 import org.qortal.asset.Asset;
+import org.qortal.controller.Controller;
 import org.qortal.controller.tradebot.AcctTradeBot;
 import org.qortal.controller.tradebot.TradeBot;
 import org.qortal.crosschain.ForeignBlockchain;
@@ -136,6 +137,9 @@ public class CrossChainTradeBotResource {
 		if (tradeBotCreateRequest.qortAmount <= 0 || tradeBotCreateRequest.fundingQortAmount <= 0)
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.ORDER_SIZE_TOO_SMALL);
 
+		if (!Controller.getInstance().isUpToDate())
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCKCHAIN_NEEDS_SYNC);
+
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			// Do some simple checking first
 			Account creator = new PublicKeyAccount(repository, tradeBotCreateRequest.creatorPublicKey);
@@ -193,6 +197,9 @@ public class CrossChainTradeBotResource {
 		if (tradeBotRespondRequest.receivingAddress == null || !Crypto.isValidAddress(tradeBotRespondRequest.receivingAddress))
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
 
+		if (!Controller.getInstance().isUpToDate())
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCKCHAIN_NEEDS_SYNC);
+
 		// Extract data from cross-chain trading AT
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			ATData atData = fetchAtDataWithChecking(repository, atAddress);

src/main/java/org/qortal/api/resource/ListsResource.java

@@ -1,6 +1,7 @@
 package org.qortal.api.resource;
 
 import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.media.ArraySchema;
 import io.swagger.v3.oas.annotations.media.Content;
 import io.swagger.v3.oas.annotations.media.Schema;
 import io.swagger.v3.oas.annotations.parameters.RequestBody;
@@ -8,7 +9,7 @@ import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import io.swagger.v3.oas.annotations.tags.Tag;
 
 import org.qortal.api.*;
-import org.qortal.api.model.AddressListRequest;
+import org.qortal.api.model.ListRequest;
 import org.qortal.crypto.Crypto;
 import org.qortal.data.account.AccountData;
 import org.qortal.list.ResourceListManager;
@@ -28,37 +29,9 @@ public class ListsResource {
 
 	@Context
 	HttpServletRequest request;
-	
-	@POST
-	@Path("/blacklist/address/{address}")
-	@Operation(
-		summary = "Add a QORT address to the local blacklist",
-		responses = {
-			@ApiResponse(
-				description = "Returns true on success, or an exception on failure",
-					content = @Content(mediaType = MediaType.TEXT_PLAIN, schema = @Schema(type = "boolean"))
-			)
-		}
-	)
-	@ApiErrors({ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN, ApiError.REPOSITORY_ISSUE})
-	public String addAddressToBlacklist(@PathParam("address") String address) {
-		if (!Crypto.isValidAddress(address))
-			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
 
-		try (final Repository repository = RepositoryManager.getRepository()) {
-			AccountData accountData = repository.getAccountRepository().getAccount(address);
-			// Not found?
-			if (accountData == null)
-				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.ADDRESS_UNKNOWN);
 
-			// Valid address, so go ahead and blacklist it
-			boolean success = ResourceListManager.getInstance().addAddressToBlacklist(address, true);
-
-			return success ? "true" : "false";
-		} catch (DataException e) {
-			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
-		}
-	}
+	/* Address blacklist */
 
 	@POST
 	@Path("/blacklist/addresses")
@@ -69,7 +42,7 @@ public class ListsResource {
 					content = @Content(
 							mediaType = MediaType.APPLICATION_JSON,
 							schema = @Schema(
-									implementation = AddressListRequest.class
+									implementation = ListRequest.class
 							)
 					)
 			),
@@ -83,8 +56,10 @@ public class ListsResource {
 			}
 	)
 	@ApiErrors({ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN, ApiError.REPOSITORY_ISSUE})
-	public String addAddressesToBlacklist(AddressListRequest addressListRequest) {
-		if (addressListRequest == null || addressListRequest.addresses == null) {
+	public String addAddressesToBlacklist(ListRequest listRequest) {
+		Security.checkApiCallAllowed(request);
+
+		if (listRequest == null || listRequest.items == null) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
 		}
 
@@ -93,7 +68,7 @@ public class ListsResource {
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
 
-			for (String address : addressListRequest.addresses) {
+			for (String address : listRequest.items) {
 
 				if (!Crypto.isValidAddress(address)) {
 					errorCount++;
@@ -108,7 +83,7 @@ public class ListsResource {
 				}
 
 				// Valid address, so go ahead and blacklist it
-				boolean success = ResourceListManager.getInstance().addAddressToBlacklist(address, false);
+				boolean success = ResourceListManager.getInstance().addToList("blacklist", "addresses", address, false);
 				if (success) {
 					successCount++;
 				}
@@ -122,48 +97,16 @@ public class ListsResource {
 
 		if (successCount > 0 && errorCount == 0) {
 			// All were successful, so save the blacklist
-			ResourceListManager.getInstance().saveBlacklist();
+			ResourceListManager.getInstance().saveList("blacklist", "addresses");
 			return "true";
 		}
 		else {
 			// Something went wrong, so revert
-			ResourceListManager.getInstance().revertBlacklist();
+			ResourceListManager.getInstance().revertList("blacklist", "addresses");
 			return "false";
 		}
 	}
 
-
-	@DELETE
-	@Path("/blacklist/address/{address}")
-	@Operation(
-			summary = "Remove a QORT address from the local blacklist",
-			responses = {
-					@ApiResponse(
-							description = "Returns true on success, or an exception on failure",
-							content = @Content(mediaType = MediaType.TEXT_PLAIN, schema = @Schema(type = "boolean"))
-					)
-			}
-	)
-	@ApiErrors({ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN, ApiError.REPOSITORY_ISSUE})
-	public String removeAddressFromBlacklist(@PathParam("address") String address) {
-		if (!Crypto.isValidAddress(address))
-			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
-
-		try (final Repository repository = RepositoryManager.getRepository()) {
-			AccountData accountData = repository.getAccountRepository().getAccount(address);
-			// Not found?
-			if (accountData == null)
-				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.ADDRESS_UNKNOWN);
-
-			// Valid address, so go ahead and blacklist it
-			boolean success = ResourceListManager.getInstance().removeAddressFromBlacklist(address, true);
-
-			return success ? "true" : "false";
-		} catch (DataException e) {
-			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
-		}
-	}
-
 	@DELETE
 	@Path("/blacklist/addresses")
 	@Operation(
@@ -173,7 +116,7 @@ public class ListsResource {
 					content = @Content(
 							mediaType = MediaType.APPLICATION_JSON,
 							schema = @Schema(
-									implementation = AddressListRequest.class
+									implementation = ListRequest.class
 							)
 					)
 			),
@@ -187,8 +130,10 @@ public class ListsResource {
 			}
 	)
 	@ApiErrors({ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN, ApiError.REPOSITORY_ISSUE})
-	public String removeAddressesFromBlacklist(AddressListRequest addressListRequest) {
-		if (addressListRequest == null || addressListRequest.addresses == null) {
+	public String removeAddressesFromBlacklist(ListRequest listRequest) {
+		Security.checkApiCallAllowed(request);
+
+		if (listRequest == null || listRequest.items == null) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
 		}
 
@@ -197,7 +142,7 @@ public class ListsResource {
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
 
-			for (String address : addressListRequest.addresses) {
+			for (String address : listRequest.items) {
 
 				if (!Crypto.isValidAddress(address)) {
 					errorCount++;
@@ -213,7 +158,7 @@ public class ListsResource {
 
 				// Valid address, so go ahead and blacklist it
 				// Don't save as we will do this at the end of the process
-				boolean success = ResourceListManager.getInstance().removeAddressFromBlacklist(address, false);
+				boolean success = ResourceListManager.getInstance().removeFromList("blacklist", "addresses", address, false);
 				if (success) {
 					successCount++;
 				}
@@ -227,45 +172,30 @@ public class ListsResource {
 
 		if (successCount > 0 && errorCount == 0) {
 			// All were successful, so save the blacklist
-			ResourceListManager.getInstance().saveBlacklist();
+			ResourceListManager.getInstance().saveList("blacklist", "addresses");
 			return "true";
 		}
 		else {
 			// Something went wrong, so revert
-			ResourceListManager.getInstance().revertBlacklist();
+			ResourceListManager.getInstance().revertList("blacklist", "addresses");
 			return "false";
 		}
 	}
 
 	@GET
-	@Path("/blacklist/address/{address}")
+	@Path("/blacklist/addresses")
 	@Operation(
-			summary = "Check if an address is present in the local blacklist",
+			summary = "Fetch the list of blacklisted addresses",
 			responses = {
 					@ApiResponse(
-							description = "Returns true or false if the list was queried, or an exception on failure",
-							content = @Content(mediaType = MediaType.TEXT_PLAIN, schema = @Schema(type = "boolean"))
+							description = "A JSON array of addresses",
+							content = @Content(mediaType = MediaType.APPLICATION_JSON, array = @ArraySchema(schema = @Schema(implementation = String.class)))
 					)
 			}
 	)
-	@ApiErrors({ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN, ApiError.REPOSITORY_ISSUE})
-	public String checkAddressInBlacklist(@PathParam("address") String address) {
-		if (!Crypto.isValidAddress(address))
-			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
-
-		try (final Repository repository = RepositoryManager.getRepository()) {
-			AccountData accountData = repository.getAccountRepository().getAccount(address);
-			// Not found?
-			if (accountData == null)
-				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.ADDRESS_UNKNOWN);
-
-			// Valid address, so go ahead and blacklist it
-			boolean blacklisted = ResourceListManager.getInstance().isAddressInBlacklist(address);
-
-			return blacklisted ? "true" : "false";
-		} catch (DataException e) {
-			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
-		}
+	public String getAddressBlacklist() {
+		Security.checkApiCallAllowed(request);
+		return ResourceListManager.getInstance().getJSONStringForList("blacklist", "addresses");
 	}
 
 }

src/main/java/org/qortal/block/Block.java

@@ -1092,9 +1092,14 @@ public class Block {
 			// Create repository savepoint here so we can rollback to it after testing transactions
 			repository.setSavepoint();
 
-			if (this.blockData.getHeight() == 212937)
+			if (this.blockData.getHeight() == 212937) {
 				// Apply fix for block 212937 but fix will be rolled back before we exit method
 				Block212937.processFix(this);
+			}
+			else if (InvalidNameRegistrationBlocks.isAffectedBlock(this.blockData.getHeight())) {
+				// Apply fix for affected name registration blocks, but fix will be rolled back before we exit method
+				InvalidNameRegistrationBlocks.processFix(this);
+			}
 
 			for (Transaction transaction : this.getTransactions()) {
 				TransactionData transactionData = transaction.getTransactionData();
@@ -1133,7 +1138,7 @@ public class Block {
 				// Check transaction can even be processed
 				validationResult = transaction.isProcessable();
 				if (validationResult != Transaction.ValidationResult.OK) {
-					LOGGER.debug(String.format("Error during transaction validation, tx %s: %s", Base58.encode(transactionData.getSignature()), validationResult.name()));
+					LOGGER.info(String.format("Error during transaction validation, tx %s: %s", Base58.encode(transactionData.getSignature()), validationResult.name()));
 					return ValidationResult.TRANSACTION_INVALID;
 				}
 
@@ -1282,6 +1287,21 @@ public class Block {
 		return mintingAccount.canMint();
 	}
 
+	/**
+	 * Pre-process block, and its transactions.
+	 * This allows for any database integrity checks prior to validation.
+	 * This is called before isValid() and process()
+	 *
+	 * @throws DataException
+	 */
+	public void preProcess() throws DataException {
+		List<Transaction> blocksTransactions = this.getTransactions();
+
+		for (Transaction transaction : blocksTransactions) {
+			transaction.preProcess();
+		}
+	}
+
 	/**
 	 * Process block, and its transactions, adding them to the blockchain.
 	 * 

src/main/java/org/qortal/block/BlockChain.java

@@ -4,10 +4,7 @@ import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.InputStream;
 import java.sql.SQLException;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 import java.util.concurrent.locks.ReentrantLock;
 
 import javax.xml.bind.JAXBContext;
@@ -27,11 +24,9 @@ import org.eclipse.persistence.jaxb.UnmarshallerProperties;
 import org.qortal.controller.Controller;
 import org.qortal.data.block.BlockData;
 import org.qortal.network.Network;
-import org.qortal.repository.BlockRepository;
-import org.qortal.repository.DataException;
-import org.qortal.repository.Repository;
-import org.qortal.repository.RepositoryManager;
+import org.qortal.repository.*;
 import org.qortal.settings.Settings;
+import org.qortal.utils.Base58;
 import org.qortal.utils.StringLongMapXmlAdapter;
 
 /**
@@ -506,29 +501,105 @@ public class BlockChain {
 	 * @throws SQLException
 	 */
 	public static void validate() throws DataException {
-		// Check first block is Genesis Block
-		if (!isGenesisBlockValid())
-			rebuildBlockchain();
 
+		boolean isTopOnly = Settings.getInstance().isTopOnly();
+		boolean archiveEnabled = Settings.getInstance().isArchiveEnabled();
+		boolean canBootstrap = Settings.getInstance().getBootstrap();
+		boolean needsArchiveRebuild = false;
+		BlockData chainTip;
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			chainTip = repository.getBlockRepository().getLastBlock();
+
+			// Ensure archive is (at least partially) intact, and force a bootstrap if it isn't
+			if (!isTopOnly && archiveEnabled && canBootstrap) {
+				needsArchiveRebuild = (repository.getBlockArchiveRepository().fromHeight(2) == null);
+				if (needsArchiveRebuild) {
+					LOGGER.info("Couldn't retrieve block 2 from archive. Bootstrapping...");
+
+					// If there are minting accounts, make sure to back them up
+					// Don't backup if there are no minting accounts, as this can cause problems
+					if (!repository.getAccountRepository().getMintingAccounts().isEmpty()) {
+						Controller.getInstance().exportRepositoryData();
+					}
+				}
+			}
+		}
+
+		boolean hasBlocks = (chainTip != null && chainTip.getHeight() > 1);
+
+		if (isTopOnly && hasBlocks) {
+			// Top-only mode is enabled and we have blocks, so it's possible that the genesis block has been pruned
+			// It's best not to validate it, and there's no real need to
+		} else {
+			// Check first block is Genesis Block
+			if (!isGenesisBlockValid() || needsArchiveRebuild) {
+				try {
+					rebuildBlockchain();
+
+				} catch (InterruptedException e) {
+					throw new DataException(String.format("Interrupted when trying to rebuild blockchain: %s", e.getMessage()));
+				}
+			}
+		}
+
+		// We need to create a new connection, as the previous repository and its connections may be been
+		// closed by rebuildBlockchain() if a bootstrap was applied
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			repository.checkConsistency();
 
-			int startHeight = Math.max(repository.getBlockRepository().getBlockchainHeight() - 1440, 1);
+			// Set the number of blocks to validate based on the pruned state of the chain
+			// If pruned, subtract an extra 10 to allow room for error
+			int blocksToValidate = (isTopOnly || archiveEnabled) ? Settings.getInstance().getPruneBlockLimit() - 10 : 1440;
 
+			int startHeight = Math.max(repository.getBlockRepository().getBlockchainHeight() - blocksToValidate, 1);
 			BlockData detachedBlockData = repository.getBlockRepository().getDetachedBlockSignature(startHeight);
 
 			if (detachedBlockData != null) {
-				LOGGER.error(String.format("Block %d's reference does not match any block's signature", detachedBlockData.getHeight()));
+				LOGGER.error(String.format("Block %d's reference does not match any block's signature",
+						detachedBlockData.getHeight()));
+				LOGGER.error(String.format("Your chain may be invalid and you should consider bootstrapping" +
+						" or re-syncing from genesis."));
+			}
+		}
+	}
 
-				// Wait for blockchain lock (whereas orphan() only tries to get lock)
-				ReentrantLock blockchainLock = Controller.getInstance().getBlockchainLock();
-				blockchainLock.lock();
-				try {
-					LOGGER.info(String.format("Orphaning back to block %d", detachedBlockData.getHeight() - 1));
-					orphan(detachedBlockData.getHeight() - 1);
-				} finally {
-					blockchainLock.unlock();
+	/**
+	 * More thorough blockchain validation method. Useful for validating bootstraps.
+	 * A DataException is thrown if anything is invalid.
+	 *
+	 * @throws DataException
+	 */
+	public static void validateAllBlocks() throws DataException {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			BlockData chainTip = repository.getBlockRepository().getLastBlock();
+			final int chainTipHeight = chainTip.getHeight();
+			final int oldestBlock = 1; // TODO: increase if in pruning mode
+			byte[] lastReference = null;
+
+			for (int height = chainTipHeight; height > oldestBlock; height--) {
+				BlockData blockData = repository.getBlockRepository().fromHeight(height);
+				if (blockData == null) {
+					blockData = repository.getBlockArchiveRepository().fromHeight(height);
 				}
+
+				if (blockData == null) {
+					String error = String.format("Missing block at height %d", height);
+					LOGGER.error(error);
+					throw new DataException(error);
+				}
+
+				if (height != chainTipHeight) {
+					// Check reference
+					if (!Arrays.equals(blockData.getSignature(), lastReference)) {
+						String error = String.format("Invalid reference for block at height %d: %s (should be %s)",
+								height, Base58.encode(blockData.getReference()), Base58.encode(lastReference));
+						LOGGER.error(error);
+						throw new DataException(error);
+					}
+				}
+
+				lastReference = blockData.getReference();
 			}
 		}
 	}
@@ -551,7 +622,15 @@ public class BlockChain {
 		}
 	}
 
-	private static void rebuildBlockchain() throws DataException {
+	private static void rebuildBlockchain() throws DataException, InterruptedException {
+		boolean shouldBootstrap = Settings.getInstance().getBootstrap();
+		if (shouldBootstrap) {
+			// Settings indicate that we should apply a bootstrap rather than rebuilding and syncing from genesis
+			Bootstrap bootstrap = new Bootstrap();
+			bootstrap.startImport();
+			return;
+		}
+
 		// (Re)build repository
 		if (!RepositoryManager.wasPristineAtOpen())
 			RepositoryManager.rebuild();

src/main/java/org/qortal/block/InvalidNameRegistrationBlocks.java

@@ -0,0 +1,114 @@
+package org.qortal.block;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.naming.Name;
+import org.qortal.repository.DataException;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Invalid Name Registration Blocks
+ * <p>
+ * A node minted a version of block 535658 that contained one transaction:
+ * a REGISTER_NAME transaction that attempted to register a name that was already registered.
+ * <p>
+ * This invalid transaction made block 535658 (rightly) invalid to several nodes,
+ * which refused to use that block.
+ * However, it seems there were no other nodes minting an alternative, valid block at that time
+ * and so the chain stalled for several nodes in the network.
+ * <p>
+ * Additionally, the invalid block 535658 affected all new installations, regardless of whether
+ * they synchronized from scratch (block 1) or used an 'official release' bootstrap.
+ * <p>
+ * The diagnosis found the following:
+ * - The original problem occurred in block 535205 where for some unknown reason many nodes didn't
+ *   add the name from a REGISTER_NAME transaction to their Names table.
+ * - As a result, those nodes had a corrupt db, because they weren't holding a record of the name.
+ * - This invalid db then caused them to treat a candidate for block 535658 as valid when it
+ *   should have been invalid.
+ * - As such, the chain continued on with a technically invalid block in it, for a subset of the network
+ * <p>
+ * As with block 212937, there were three options, but the only feasible one was to apply edits to block
+ * 535658 to make it valid. There were several cross-chain trades completed after this block, so doing
+ * any kind of rollback was out of the question.
+ * <p>
+ * To complicate things further, a custom data field was used for the first REGISTER_NAME transaction,
+ * and the default data field was used for the second. So it was important that all nodes ended up with
+ * the exact same data regardless of how they arrived there.
+ * <p>
+ * The invalid block 535658 signature is: <tt>3oiuDhok...NdXvCLEV</tt>.
+ * <p>
+ * The invalid transaction in block 212937 is:
+ * <p>
+ * <code><pre>
+	 {
+		 "type": "REGISTER_NAME",
+		 "timestamp": 1630739437517,
+		 "reference": "4peRechwSPxP6UkRj9Y8ox9YxkWb34sWk5zyMc1WyMxEsACxD4Gmm7LZVsQ6Skpze8QCSBMZasvEZg6RgdqkyADW",
+		 "fee": "0.00100000",
+		 "signature": "2t1CryCog8KPDBarzY5fDCKu499nfnUcGrz4Lz4w5wNb5nWqm7y126P48dChYY7huhufcBV3RJPkgKP4Ywxc1gXx",
+		 "txGroupId": 0,
+		 "blockHeight": 535658,
+		 "approvalStatus": "NOT_REQUIRED",
+		 "creatorAddress": "Qbx9ojxv7XNi1xDMWzzw7xDvd1zYW6SKFB",
+		 "registrantPublicKey": "HJqGEf6cW695Xun4ydhkB2excGFwsDxznhNCRHZStyyx",
+		 "name": "Qplay",
+		 "data": "Registered Name on the Qortal Chain"
+	 }
+   </pre></code>
+ * <p>
+ * Account <tt>Qbx9ojxv7XNi1xDMWzzw7xDvd1zYW6SKFB</tt> attempted to register the name <tt>Qplay</tt>
+ * when they had already registered it 12 hours before in block <tt>535205</tt>.
+ * <p>
+ * However, on the broken DB nodes, their Names table was missing a record for the `Qplay` name
+ * which was sufficient to make the transaction valid.
+ *
+ * This problem then occurred two more times, in blocks 536140 and 541334
+ * To reduce duplication, I have combined all three block fixes into a single class
+ *
+ */
+public final class InvalidNameRegistrationBlocks {
+
+	private static final Logger LOGGER = LogManager.getLogger(InvalidNameRegistrationBlocks.class);
+
+	public static Map<Integer, String> invalidBlocksNamesMap = new HashMap<Integer, String>()
+	{
+		{
+			put(535658, "Qplay");
+			put(536140, "Qweb");
+			put(541334, "Qithub");
+		}
+	};
+
+	private InvalidNameRegistrationBlocks() {
+		/* Do not instantiate */
+	}
+
+	public static boolean isAffectedBlock(int height) {
+		return (invalidBlocksNamesMap.containsKey(height));
+	}
+
+	public static void processFix(Block block) throws DataException {
+		Integer blockHeight = block.getBlockData().getHeight();
+		String invalidName = invalidBlocksNamesMap.get(blockHeight);
+		if (invalidName == null) {
+			throw new DataException(String.format("Unable to lookup invalid name for block height %d", blockHeight));
+		}
+
+		// Unregister the existing name record if it exists
+		// This ensures that the duplicate name is considered valid, and therefore
+		// the second (i.e. duplicate) REGISTER_NAME transaction data is applied.
+		// Both were issued by the same user account, so there is no conflict.
+		Name name = new Name(block.repository, invalidName);
+		name.unregister();
+
+		LOGGER.debug("Applied name registration patch for block {}", blockHeight);
+	}
+
+	// Note:
+	// There is no need to write an orphanFix() method, as we do not have
+	// the necessary ATStatesData to orphan back this far anyway
+
+}

src/main/java/org/qortal/controller/AutoUpdate.java

@@ -14,6 +14,7 @@ import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.concurrent.TimeoutException;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -215,8 +216,17 @@ public class AutoUpdate extends Thread {
 		}
 
 		// Give repository a chance to backup in case things go badly wrong (if enabled)
-		if (Settings.getInstance().getRepositoryBackupInterval() > 0)
-			RepositoryManager.backup(true);
+		if (Settings.getInstance().getRepositoryBackupInterval() > 0) {
+			try {
+				// Timeout if the database isn't ready for backing up after 60 seconds
+				long timeout = 60 * 1000L;
+				RepositoryManager.backup(true, "backup", timeout);
+
+			} catch (TimeoutException e) {
+				LOGGER.info("Attempt to backup repository failed due to timeout: {}", e.getMessage());
+				// Continue with the auto update anyway...
+			}
+		}
 
 		// Call ApplyUpdate to end this process (unlocking current JAR so it can be replaced)
 		String javaHome = System.getProperty("java.home");

src/main/java/org/qortal/controller/BlockMinter.java

@@ -16,6 +16,7 @@ import org.qortal.account.PrivateKeyAccount;
 import org.qortal.block.Block;
 import org.qortal.block.Block.ValidationResult;
 import org.qortal.block.BlockChain;
+import org.qortal.data.account.AccountData;
 import org.qortal.data.account.MintingAccountData;
 import org.qortal.data.account.RewardShareData;
 import org.qortal.data.block.BlockData;
@@ -44,6 +45,14 @@ public class BlockMinter extends Thread {
 	private static Long lastLogTimestamp;
 	private static Long logTimeout;
 
+	// Recovery
+	public static final long INVALID_BLOCK_RECOVERY_TIMEOUT = 10 * 60 * 1000L; // ms
+
+	// Min account level to submit blocks
+	// This is an unvalidated version of Blockchain.minAccountLevelToMint
+	// and exists only to reduce block candidates by default.
+	private static int MIN_LEVEL_FOR_BLOCK_SUBMISSION = 3;
+
 	// Constructors
 
 	public BlockMinter() {
@@ -127,6 +136,16 @@ public class BlockMinter extends Thread {
 						madi.remove();
 						continue;
 					}
+
+					// Optional (non-validated) prevention of block submissions below a defined level
+					AccountData accountData = repository.getAccountRepository().getAccount(mintingAccount.getAddress());
+					if (accountData != null) {
+						Integer level = accountData.getLevel();
+						if (level != null && level < MIN_LEVEL_FOR_BLOCK_SUBMISSION) {
+							madi.remove();
+							continue;
+						}
+					}
 				}
 
 				List<Peer> peers = Network.getInstance().getHandshakedPeers();
@@ -144,9 +163,25 @@ public class BlockMinter extends Thread {
 				if (peers.size() < Settings.getInstance().getMinBlockchainPeers())
 					continue;
 
+				// If we are stuck on an invalid block, we should allow an alternative to be minted
+				boolean recoverInvalidBlock = false;
+				if (Synchronizer.getInstance().timeInvalidBlockLastReceived != null) {
+					// We've had at least one invalid block
+					long timeSinceLastValidBlock = NTP.getTime() - Synchronizer.getInstance().timeValidBlockLastReceived;
+					long timeSinceLastInvalidBlock = NTP.getTime() - Synchronizer.getInstance().timeInvalidBlockLastReceived;
+					if (timeSinceLastValidBlock > INVALID_BLOCK_RECOVERY_TIMEOUT) {
+						if (timeSinceLastInvalidBlock < INVALID_BLOCK_RECOVERY_TIMEOUT) {
+							// Last valid block was more than 10 mins ago, but we've had an invalid block since then
+							// Assume that the chain has stalled because there is no alternative valid candidate
+							// Enter recovery mode to allow alternative, valid candidates to be minted
+							recoverInvalidBlock = true;
+						}
+					}
+				}
+
 				// If our latest block isn't recent then we need to synchronize instead of minting, unless we're in recovery mode.
 				if (!peers.isEmpty() && lastBlockData.getTimestamp() < minLatestBlockTimestamp)
-					if (Controller.getInstance().getRecoveryMode() == false)
+					if (Controller.getInstance().getRecoveryMode() == false && recoverInvalidBlock == false)
 						continue;
 
 				// There are enough peers with a recent block and our latest block is recent
@@ -230,6 +265,8 @@ public class BlockMinter extends Thread {
 						if (testBlock.isTimestampValid() != ValidationResult.OK)
 							continue;
 
+						testBlock.preProcess();
+
 						// Is new block valid yet? (Before adding unconfirmed transactions)
 						ValidationResult result = testBlock.isValid();
 						if (result != ValidationResult.OK) {
@@ -421,7 +458,8 @@ public class BlockMinter extends Thread {
 
 			// Add to blockchain
 			newBlock.process();
-			LOGGER.info(String.format("Minted new test block: %d", newBlock.getBlockData().getHeight()));
+			LOGGER.info(String.format("Minted new test block: %d sig: %.8s",
+					newBlock.getBlockData().getHeight(), Base58.encode(newBlock.getBlockData().getSignature())));
 
 			repository.saveChanges();
 

src/main/java/org/qortal/controller/Controller.java

@@ -2,8 +2,11 @@ package org.qortal.controller;
 
 import java.awt.TrayIcon.MessageType;
 import java.io.File;
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.security.SecureRandom;
 import java.security.Security;
 import java.time.LocalDateTime;
@@ -24,7 +27,7 @@ import java.util.Properties;
 import java.util.Random;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
-import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.Function;
@@ -46,6 +49,8 @@ import org.qortal.block.Block;
 import org.qortal.block.BlockChain;
 import org.qortal.block.BlockChain.BlockTimingByHeight;
 import org.qortal.controller.Synchronizer.SynchronizationResult;
+import org.qortal.controller.repository.PruneManager;
+import org.qortal.controller.repository.NamesDatabaseIntegrityCheck;
 import org.qortal.controller.tradebot.TradeBot;
 import org.qortal.crypto.Crypto;
 import org.qortal.data.account.MintingAccountData;
@@ -83,21 +88,14 @@ import org.qortal.network.message.OnlineAccountsMessage;
 import org.qortal.network.message.SignaturesMessage;
 import org.qortal.network.message.TransactionMessage;
 import org.qortal.network.message.TransactionSignaturesMessage;
-import org.qortal.repository.DataException;
-import org.qortal.repository.Repository;
-import org.qortal.repository.RepositoryFactory;
-import org.qortal.repository.RepositoryManager;
+import org.qortal.repository.*;
 import org.qortal.repository.hsqldb.HSQLDBRepositoryFactory;
 import org.qortal.settings.Settings;
 import org.qortal.transaction.ArbitraryTransaction;
 import org.qortal.transaction.Transaction;
 import org.qortal.transaction.Transaction.TransactionType;
 import org.qortal.transaction.Transaction.ValidationResult;
-import org.qortal.utils.Base58;
-import org.qortal.utils.ByteArray;
-import org.qortal.utils.DaemonThreadFactory;
-import org.qortal.utils.NTP;
-import org.qortal.utils.Triple;
+import org.qortal.utils.*;
 
 import com.google.common.primitives.Longs;
 
@@ -105,6 +103,7 @@ public class Controller extends Thread {
 
 	static {
 		// This must go before any calls to LogManager/Logger
+		System.setProperty("log4j2.formatMsgNoLookups", "true");
 		System.setProperty("java.util.logging.manager", "org.apache.logging.log4j.jul.LogManager");
 	}
 
@@ -157,6 +156,7 @@ public class Controller extends Thread {
 	};
 
 	private long repositoryBackupTimestamp = startTime; // ms
+	private long repositoryMaintenanceTimestamp = startTime; // ms
 	private long repositoryCheckpointTimestamp = startTime; // ms
 	private long ntpCheckTimestamp = startTime; // ms
 	private long deleteExpiredTimestamp = startTime + DELETE_EXPIRED_INTERVAL; // ms
@@ -314,6 +314,10 @@ public class Controller extends Thread {
 		return this.buildVersion;
 	}
 
+	public String getVersionStringWithoutPrefix() {
+		return this.buildVersion.replaceFirst(VERSION_PREFIX, "");
+	}
+
 	/** Returns current blockchain height, or 0 if it's not available. */
 	public int getChainHeight() {
 		synchronized (this.latestBlocks) {
@@ -357,7 +361,7 @@ public class Controller extends Thread {
 		return this.savedArgs;
 	}
 
-	/* package */ static boolean isStopping() {
+	public static boolean isStopping() {
 		return isStopping;
 	}
 
@@ -415,6 +419,12 @@ public class Controller extends Thread {
 		try {
 			RepositoryFactory repositoryFactory = new HSQLDBRepositoryFactory(getRepositoryUrl());
 			RepositoryManager.setRepositoryFactory(repositoryFactory);
+			RepositoryManager.setRequestedCheckpoint(Boolean.TRUE);
+
+			try (final Repository repository = RepositoryManager.getRepository()) {
+				RepositoryManager.archive(repository);
+				RepositoryManager.prune(repository);
+			}
 		} catch (DataException e) {
 			// If exception has no cause then repository is in use by some other process.
 			if (e.getCause() == null) {
@@ -428,6 +438,11 @@ public class Controller extends Thread {
 			return; // Not System.exit() so that GUI can display error
 		}
 
+		// Rebuild Names table and check database integrity
+		NamesDatabaseIntegrityCheck namesDatabaseIntegrityCheck = new NamesDatabaseIntegrityCheck();
+		namesDatabaseIntegrityCheck.rebuildAllNames();
+		namesDatabaseIntegrityCheck.runIntegrityCheck();
+
 		LOGGER.info("Validating blockchain");
 		try {
 			BlockChain.validate();
@@ -440,6 +455,12 @@ public class Controller extends Thread {
 			return; // Not System.exit() so that GUI can display error
 		}
 
+		// Import current trade bot states and minting accounts if they exist
+		Controller.importRepositoryData();
+
+		// Add the initial peers to the repository if we don't have any
+		Controller.installInitialPeers();
+
 		LOGGER.info("Starting controller");
 		Controller.getInstance().start();
 
@@ -509,10 +530,10 @@ public class Controller extends Thread {
 
 		final long repositoryBackupInterval = Settings.getInstance().getRepositoryBackupInterval();
 		final long repositoryCheckpointInterval = Settings.getInstance().getRepositoryCheckpointInterval();
+		long repositoryMaintenanceInterval = getRandomRepositoryMaintenanceInterval();
 
-		ExecutorService trimExecutor = Executors.newCachedThreadPool(new DaemonThreadFactory());
-		trimExecutor.execute(new AtStatesTrimmer());
-		trimExecutor.execute(new OnlineAccountsSignaturesTrimmer());
+		// Start executor service for trimming or pruning
+		PruneManager.getInstance().start();
 
 		try {
 			while (!isStopping) {
@@ -570,7 +591,39 @@ public class Controller extends Thread {
 								Translator.INSTANCE.translate("SysTray", "CREATING_BACKUP_OF_DB_FILES"),
 								MessageType.INFO);
 
-					RepositoryManager.backup(true);
+					try {
+						// Timeout if the database isn't ready for backing up after 60 seconds
+						long timeout = 60 * 1000L;
+						RepositoryManager.backup(true, "backup", timeout);
+
+					} catch (TimeoutException e) {
+						LOGGER.info("Attempt to backup repository failed due to timeout: {}", e.getMessage());
+					}
+				}
+
+				// Give repository a chance to perform maintenance (if enabled)
+				if (repositoryMaintenanceInterval > 0 && now >= repositoryMaintenanceTimestamp + repositoryMaintenanceInterval) {
+					repositoryMaintenanceTimestamp = now + repositoryMaintenanceInterval;
+
+					if (Settings.getInstance().getShowMaintenanceNotification())
+						SysTray.getInstance().showMessage(Translator.INSTANCE.translate("SysTray", "DB_MAINTENANCE"),
+								Translator.INSTANCE.translate("SysTray", "PERFORMING_DB_MAINTENANCE"),
+								MessageType.INFO);
+
+					LOGGER.info("Starting scheduled repository maintenance. This can take a while...");
+					try (final Repository repository = RepositoryManager.getRepository()) {
+
+						// Timeout if the database isn't ready for maintenance after 60 seconds
+						long timeout = 60 * 1000L;
+						repository.performPeriodicMaintenance(timeout);
+
+						LOGGER.info("Scheduled repository maintenance completed");
+					} catch (DataException | TimeoutException e) {
+						LOGGER.error("Scheduled repository maintenance failed", e);
+					}
+
+					// Get a new random interval
+					repositoryMaintenanceInterval = getRandomRepositoryMaintenanceInterval();
 				}
 
 				// Prune stuck/slow/old peers
@@ -597,13 +650,68 @@ public class Controller extends Thread {
 			Thread.interrupted();
 			// Fall-through to exit
 		} finally {
-			trimExecutor.shutdownNow();
+			PruneManager.getInstance().stop();
+		}
+	}
+
+	/**
+	 * Import current trade bot states and minting accounts.
+	 * This is needed because the user may have bootstrapped, or there could be a database inconsistency
+	 * if the core crashed when computing the nonce during the start of the trade process.
+	 */
+	private static void importRepositoryData() {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+
+			String exportPath = Settings.getInstance().getExportPath();
+			try {
+				Path importPath = Paths.get(exportPath, "TradeBotStates.json");
+				repository.importDataFromFile(importPath.toString());
+			} catch (FileNotFoundException e) {
+				// Do nothing, as the files will only exist in certain cases
+			}
 
 			try {
-				trimExecutor.awaitTermination(2L, TimeUnit.SECONDS);
-			} catch (InterruptedException e) {
-				// We tried...
+				Path importPath = Paths.get(exportPath, "MintingAccounts.json");
+				repository.importDataFromFile(importPath.toString());
+			} catch (FileNotFoundException e) {
+				// Do nothing, as the files will only exist in certain cases
 			}
+			repository.saveChanges();
+		}
+		catch (DataException | IOException e) {
+			LOGGER.info("Unable to import data into repository: {}", e.getMessage());
+		}
+	}
+
+	private static void installInitialPeers() {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			if (repository.getNetworkRepository().getAllPeers().isEmpty()) {
+				Network.installInitialPeers(repository);
+			}
+
+		} catch (DataException e) {
+			// Fail silently as this is an optional step
+		}
+	}
+
+	private long getRandomRepositoryMaintenanceInterval() {
+		final long minInterval = Settings.getInstance().getRepositoryMaintenanceMinInterval();
+		final long maxInterval = Settings.getInstance().getRepositoryMaintenanceMaxInterval();
+		if (maxInterval == 0) {
+			return 0;
+		}
+		return (new Random().nextLong() % (maxInterval - minInterval)) + minInterval;
+	}
+
+	/**
+	 * Export current trade bot states and minting accounts.
+	 */
+	public void exportRepositoryData() {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			repository.exportNodeLocalData();
+
+		} catch (DataException e) {
+			// Fail silently as this is an optional step
 		}
 	}
 
@@ -886,7 +994,7 @@ public class Controller extends Thread {
 			}
 		}
 
-		String tooltip = String.format("%s - %d %s - %s %d", actionText, numberOfPeers, connectionsText, heightText, height) + "\n" + String.format("Build version: %s", this.buildVersion);
+		String tooltip = String.format("%s - %d %s - %s %d", actionText, numberOfPeers, connectionsText, heightText, height) + "\n" + String.format("%s: %s", Translator.INSTANCE.translate("SysTray", "BUILD_VERSION"), this.buildVersion);
 		SysTray.getInstance().setToolTipText(tooltip);
 
 		this.callbackExecutor.execute(() -> {
@@ -958,6 +1066,10 @@ public class Controller extends Thread {
 					}
 				}
 
+				// Export local data
+				LOGGER.info("Backing up local data");
+				this.exportRepositoryData();
+
 				LOGGER.info("Shutting down networking");
 				Network.getInstance().shutdown();
 
@@ -1286,6 +1398,34 @@ public class Controller extends Thread {
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			BlockData blockData = repository.getBlockRepository().fromSignature(signature);
 
+			if (blockData != null) {
+				if (PruneManager.getInstance().isBlockPruned(blockData.getHeight())) {
+					// If this is a pruned block, we likely only have partial data, so best not to sent it
+					blockData = null;
+				}
+			}
+
+			// If we have no block data, we should check the archive in case it's there
+			if (blockData == null) {
+				if (Settings.getInstance().isArchiveEnabled()) {
+					byte[] bytes = BlockArchiveReader.getInstance().fetchSerializedBlockBytesForSignature(signature, true, repository);
+					if (bytes != null) {
+						CachedBlockMessage blockMessage = new CachedBlockMessage(bytes);
+						blockMessage.setId(message.getId());
+
+						// This call also causes the other needed data to be pulled in from repository
+						if (!peer.sendMessage(blockMessage)) {
+							peer.disconnect("failed to send block");
+							// Don't fall-through to caching because failure to send might be from failure to build message
+							return;
+						}
+
+						// Sent successfully from archive, so nothing more to do
+						return;
+					}
+				}
+			}
+
 			if (blockData == null) {
 				// We don't have this block
 				this.stats.getBlockMessageStats.unknownBlocks.getAndIncrement();
@@ -1406,12 +1546,29 @@ public class Controller extends Thread {
 				int numberRequested = Math.min(Network.MAX_BLOCK_SUMMARIES_PER_REPLY, getBlockSummariesMessage.getNumberRequested());
 
 				BlockData blockData = repository.getBlockRepository().fromReference(parentSignature);
+				if (blockData == null) {
+					// Try the archive
+					blockData = repository.getBlockArchiveRepository().fromReference(parentSignature);
+				}
+
+				if (blockData != null) {
+					if (PruneManager.getInstance().isBlockPruned(blockData.getHeight())) {
+						// If this request contains a pruned block, we likely only have partial data, so best not to sent anything
+						// We always prune from the oldest first, so it's fine to just check the first block requested
+						blockData = null;
+					}
+				}
 
 				while (blockData != null && blockSummaries.size() < numberRequested) {
 					BlockSummaryData blockSummary = new BlockSummaryData(blockData);
 					blockSummaries.add(blockSummary);
 
-					blockData = repository.getBlockRepository().fromReference(blockData.getSignature());
+					byte[] previousSignature = blockData.getSignature();
+					blockData = repository.getBlockRepository().fromReference(previousSignature);
+					if (blockData == null) {
+						// Try the archive
+						blockData = repository.getBlockArchiveRepository().fromReference(previousSignature);
+					}
 				}
 			} catch (DataException e) {
 				LOGGER.error(String.format("Repository issue while sending block summaries after %s to peer %s", Base58.encode(parentSignature), peer), e);
@@ -1460,11 +1617,20 @@ public class Controller extends Thread {
 			try (final Repository repository = RepositoryManager.getRepository()) {
 				int numberRequested = getSignaturesMessage.getNumberRequested();
 				BlockData blockData = repository.getBlockRepository().fromReference(parentSignature);
+				if (blockData == null) {
+					// Try the archive
+					blockData = repository.getBlockArchiveRepository().fromReference(parentSignature);
+				}
 
 				while (blockData != null && signatures.size() < numberRequested) {
 					signatures.add(blockData.getSignature());
 
-					blockData = repository.getBlockRepository().fromReference(blockData.getSignature());
+					byte[] previousSignature = blockData.getSignature();
+					blockData = repository.getBlockRepository().fromReference(previousSignature);
+					if (blockData == null) {
+						// Try the archive
+						blockData = repository.getBlockArchiveRepository().fromReference(previousSignature);
+					}
 				}
 			} catch (DataException e) {
 				LOGGER.error(String.format("Repository issue while sending V2 signatures after %s to peer %s", Base58.encode(parentSignature), peer), e);

src/main/java/org/qortal/controller/Synchronizer.java

@@ -3,12 +3,9 @@ package org.qortal.controller;
 import java.math.BigInteger;
 import java.text.DecimalFormat;
 import java.text.NumberFormat;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
+import java.util.*;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.stream.Collectors;
-import java.util.Iterator;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -62,6 +59,11 @@ public class Synchronizer {
 	// Keep track of the size of the last re-org, so it can be logged
 	private int lastReorgSize;
 
+	// Keep track of invalid blocks so that we don't keep trying to sync them
+	private Map<String, Long> invalidBlockSignatures = Collections.synchronizedMap(new HashMap<>());
+	public Long timeValidBlockLastReceived = null;
+	public Long timeInvalidBlockLastReceived = null;
+
 	private static Synchronizer instance;
 
 	public enum SynchronizationResult {
@@ -337,6 +339,12 @@ public class Synchronizer {
 							}
 						}
 
+						// Ignore this peer if it holds an invalid block
+						if (this.containsInvalidBlockSummary(peer.getCommonBlockData().getBlockSummariesAfterCommonBlock())) {
+							LOGGER.debug("Ignoring peer %s because it holds an invalid block", peer);
+							peers.remove(peer);
+						}
+
 						// Reduce minChainLength if needed. If we don't have any blocks, this peer will be excluded from chain weight comparisons later in the process, so we shouldn't update minChainLength
 						List <BlockSummaryData> peerBlockSummaries = peer.getCommonBlockData().getBlockSummariesAfterCommonBlock();
 						if (peerBlockSummaries != null && peerBlockSummaries.size() > 0)
@@ -480,6 +488,71 @@ public class Synchronizer {
 	}
 
 
+
+	/* Invalid block signature tracking */
+
+	private void addInvalidBlockSignature(byte[] signature) {
+		Long now = NTP.getTime();
+		if (now == null) {
+			return;
+		}
+
+		// Add or update existing entry
+		String sig58 = Base58.encode(signature);
+		invalidBlockSignatures.put(sig58, now);
+	}
+	private void deleteOlderInvalidSignatures(Long now) {
+		if (now == null) {
+			return;
+		}
+
+		// Delete signatures with older timestamps
+		Iterator it = invalidBlockSignatures.entrySet().iterator();
+		while (it.hasNext()) {
+			Map.Entry pair = (Map.Entry)it.next();
+			Long lastSeen = (Long) pair.getValue();
+
+			// Remove signature if we haven't seen it for more than 1 hour
+			if (now - lastSeen > 60 * 60 * 1000L) {
+				it.remove();
+			}
+		}
+	}
+	private boolean containsInvalidBlockSummary(List<BlockSummaryData> blockSummaries) {
+		if (blockSummaries == null || invalidBlockSignatures == null) {
+			return false;
+		}
+
+		// Loop through our known invalid blocks and check each one against supplied block summaries
+		for (String invalidSignature58 : invalidBlockSignatures.keySet()) {
+			byte[] invalidSignature = Base58.decode(invalidSignature58);
+			for (BlockSummaryData blockSummary : blockSummaries) {
+				byte[] signature = blockSummary.getSignature();
+				if (Arrays.equals(signature, invalidSignature)) {
+					return true;
+				}
+			}
+		}
+		return false;
+	}
+	private boolean containsInvalidBlockSignature(List<byte[]> blockSignatures) {
+		if (blockSignatures == null || invalidBlockSignatures == null) {
+			return false;
+		}
+
+		// Loop through our known invalid blocks and check each one against supplied block signatures
+		for (String invalidSignature58 : invalidBlockSignatures.keySet()) {
+			byte[] invalidSignature = Base58.decode(invalidSignature58);
+			for (byte[] signature : blockSignatures) {
+				if (Arrays.equals(signature, invalidSignature)) {
+					return true;
+				}
+			}
+		}
+		return false;
+	}
+
+
 	/**
 	 * Attempt to synchronize blockchain with peer.
 	 * <p>
@@ -526,6 +599,15 @@ public class Synchronizer {
 					// Reset last re-org size as we are starting a new sync round
 					this.lastReorgSize = 0;
 
+					// Set the initial value of timeValidBlockLastReceived if it's null
+					Long now = NTP.getTime();
+					if (this.timeValidBlockLastReceived == null) {
+						this.timeValidBlockLastReceived = now;
+					}
+
+					// Delete invalid signatures with older timestamps
+					this.deleteOlderInvalidSignatures(now);
+
 					List<BlockSummaryData> peerBlockSummaries = new ArrayList<>();
 					SynchronizationResult findCommonBlockResult = fetchSummariesFromCommonBlock(repository, peer, ourInitialHeight, force, peerBlockSummaries, true);
 					if (findCommonBlockResult != SynchronizationResult.OK) {
@@ -874,6 +956,12 @@ public class Synchronizer {
 				break;
 			}
 
+			// Catch a block with an invalid signature before orphaning, so that we retain our existing valid candidate
+			if (this.containsInvalidBlockSignature(peerBlockSignatures)) {
+				LOGGER.info(String.format("Peer %s sent invalid block signature: %.8s", peer, Base58.encode(latestPeerSignature)));
+				return SynchronizationResult.INVALID_DATA;
+			}
+
 			byte[] nextPeerSignature = peerBlockSignatures.get(0);
 			int nextHeight = height + 1;
 
@@ -976,13 +1064,20 @@ public class Synchronizer {
 			if (Controller.isStopping())
 				return SynchronizationResult.SHUTTING_DOWN;
 
+			newBlock.preProcess();
+
 			ValidationResult blockResult = newBlock.isValid();
 			if (blockResult != ValidationResult.OK) {
 				LOGGER.info(String.format("Peer %s sent invalid block for height %d, sig %.8s: %s", peer,
 						newBlock.getBlockData().getHeight(), Base58.encode(newBlock.getSignature()), blockResult.name()));
+				this.addInvalidBlockSignature(newBlock.getSignature());
+				this.timeInvalidBlockLastReceived = NTP.getTime();
 				return SynchronizationResult.INVALID_DATA;
 			}
 
+			// Block is valid
+			this.timeValidBlockLastReceived = NTP.getTime();
+
 			// Save transactions attached to this block
 			for (Transaction transaction : newBlock.getTransactions()) {
 				TransactionData transactionData = transaction.getTransactionData();
@@ -1064,13 +1159,20 @@ public class Synchronizer {
 			for (Transaction transaction : newBlock.getTransactions())
 				transaction.setInitialApprovalStatus();
 
+			newBlock.preProcess();
+
 			ValidationResult blockResult = newBlock.isValid();
 			if (blockResult != ValidationResult.OK) {
 				LOGGER.info(String.format("Peer %s sent invalid block for height %d, sig %.8s: %s", peer,
 						ourHeight, Base58.encode(latestPeerSignature), blockResult.name()));
+				this.addInvalidBlockSignature(newBlock.getSignature());
+				this.timeInvalidBlockLastReceived = NTP.getTime();
 				return SynchronizationResult.INVALID_DATA;
 			}
 
+			// Block is valid
+			this.timeValidBlockLastReceived = NTP.getTime();
+
 			// Save transactions attached to this block
 			for (Transaction transaction : newBlock.getTransactions()) {
 				TransactionData transactionData = transaction.getTransactionData();

src/main/java/org/qortal/controller/repository/AtStatesPruner.java

@@ -0,0 +1,109 @@
+package org.qortal.controller.repository;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.controller.Controller;
+import org.qortal.data.block.BlockData;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+import org.qortal.settings.Settings;
+import org.qortal.utils.NTP;
+
+public class AtStatesPruner implements Runnable {
+
+	private static final Logger LOGGER = LogManager.getLogger(AtStatesPruner.class);
+
+	@Override
+	public void run() {
+		Thread.currentThread().setName("AT States pruner");
+
+		boolean archiveMode = false;
+		if (!Settings.getInstance().isTopOnly()) {
+			// Top-only mode isn't enabled, but we might want to prune for the purposes of archiving
+			if (!Settings.getInstance().isArchiveEnabled()) {
+				// No pruning or archiving, so we must not prune anything
+				return;
+			}
+			else {
+				// We're allowed to prune blocks that have already been archived
+				archiveMode = true;
+			}
+		}
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			int pruneStartHeight = repository.getATRepository().getAtPruneHeight();
+
+			repository.discardChanges();
+			repository.getATRepository().rebuildLatestAtStates();
+
+			while (!Controller.isStopping()) {
+				repository.discardChanges();
+
+				Thread.sleep(Settings.getInstance().getAtStatesPruneInterval());
+
+				BlockData chainTip = Controller.getInstance().getChainTip();
+				if (chainTip == null || NTP.getTime() == null)
+					continue;
+
+				// Don't even attempt if we're mid-sync as our repository requests will be delayed for ages
+				if (Controller.getInstance().isSynchronizing())
+					continue;
+
+				// Prune AT states for all blocks up until our latest minus pruneBlockLimit
+				final int ourLatestHeight = chainTip.getHeight();
+				int upperPrunableHeight = ourLatestHeight - Settings.getInstance().getPruneBlockLimit();
+
+				// In archive mode we are only allowed to trim blocks that have already been archived
+				if (archiveMode) {
+					upperPrunableHeight = repository.getBlockArchiveRepository().getBlockArchiveHeight() - 1;
+
+					// TODO: validate that the actual archived data exists before pruning it?
+				}
+
+				int upperBatchHeight = pruneStartHeight + Settings.getInstance().getAtStatesPruneBatchSize();
+				int upperPruneHeight = Math.min(upperBatchHeight, upperPrunableHeight);
+
+				if (pruneStartHeight >= upperPruneHeight)
+					continue;
+
+				LOGGER.debug(String.format("Pruning AT states between blocks %d and %d...", pruneStartHeight, upperPruneHeight));
+
+				int numAtStatesPruned = repository.getATRepository().pruneAtStates(pruneStartHeight, upperPruneHeight);
+				repository.saveChanges();
+				int numAtStateDataRowsTrimmed = repository.getATRepository().trimAtStates(
+						pruneStartHeight, upperPruneHeight, Settings.getInstance().getAtStatesTrimLimit());
+				repository.saveChanges();
+
+				if (numAtStatesPruned > 0 || numAtStateDataRowsTrimmed > 0) {
+					final int finalPruneStartHeight = pruneStartHeight;
+					LOGGER.debug(() -> String.format("Pruned %d AT state%s between blocks %d and %d",
+							numAtStatesPruned, (numAtStatesPruned != 1 ? "s" : ""),
+							finalPruneStartHeight, upperPruneHeight));
+				} else {
+					// Can we move onto next batch?
+					if (upperPrunableHeight > upperBatchHeight) {
+						pruneStartHeight = upperBatchHeight;
+						repository.getATRepository().setAtPruneHeight(pruneStartHeight);
+						repository.getATRepository().rebuildLatestAtStates();
+						repository.saveChanges();
+
+						final int finalPruneStartHeight = pruneStartHeight;
+						LOGGER.debug(() -> String.format("Bumping AT state base prune height to %d", finalPruneStartHeight));
+					}
+					else {
+						// We've pruned up to the upper prunable height
+						// Back off for a while to save CPU for syncing
+						repository.discardChanges();
+						Thread.sleep(5*60*1000L);
+					}
+				}
+			}
+		} catch (DataException e) {
+			LOGGER.warn(String.format("Repository issue trying to prune AT states: %s", e.getMessage()));
+		} catch (InterruptedException e) {
+			// Time to exit
+		}
+	}
+
+}

src/main/java/org/qortal/controller/repository/AtStatesTrimmer.java

@@ -1,7 +1,8 @@
-package org.qortal.controller;
+package org.qortal.controller.repository;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.qortal.controller.Controller;
 import org.qortal.data.block.BlockData;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
@@ -20,8 +21,8 @@ public class AtStatesTrimmer implements Runnable {
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			int trimStartHeight = repository.getATRepository().getAtTrimHeight();
 
-			repository.getATRepository().prepareForAtStateTrimming();
-			repository.saveChanges();
+			repository.discardChanges();
+			repository.getATRepository().rebuildLatestAtStates();
 
 			while (!Controller.isStopping()) {
 				repository.discardChanges();
@@ -62,7 +63,7 @@ public class AtStatesTrimmer implements Runnable {
 					if (upperTrimmableHeight > upperBatchHeight) {
 						trimStartHeight = upperBatchHeight;
 						repository.getATRepository().setAtTrimHeight(trimStartHeight);
-						repository.getATRepository().prepareForAtStateTrimming();
+						repository.getATRepository().rebuildLatestAtStates();
 						repository.saveChanges();
 
 						final int finalTrimStartHeight = trimStartHeight;

src/main/java/org/qortal/controller/repository/BlockArchiver.java

@@ -0,0 +1,113 @@
+package org.qortal.controller.repository;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.controller.Controller;
+import org.qortal.data.block.BlockData;
+import org.qortal.repository.*;
+import org.qortal.settings.Settings;
+import org.qortal.transform.TransformationException;
+import org.qortal.utils.NTP;
+
+import java.io.IOException;
+
+public class BlockArchiver implements Runnable {
+
+	private static final Logger LOGGER = LogManager.getLogger(BlockArchiver.class);
+
+	private static final long INITIAL_SLEEP_PERIOD = 0L; // TODO: 5 * 60 * 1000L + 1234L; // ms
+
+	public void run() {
+		Thread.currentThread().setName("Block archiver");
+
+		if (!Settings.getInstance().isArchiveEnabled()) {
+			return;
+		}
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			// Don't even start building until initial rush has ended
+			Thread.sleep(INITIAL_SLEEP_PERIOD);
+
+			int startHeight = repository.getBlockArchiveRepository().getBlockArchiveHeight();
+
+			// Don't attempt to archive if we have no ATStatesHeightIndex, as it will be too slow
+			boolean hasAtStatesHeightIndex = repository.getATRepository().hasAtStatesHeightIndex();
+			if (!hasAtStatesHeightIndex) {
+				LOGGER.info("Unable to start block archiver due to missing ATStatesHeightIndex. Bootstrapping is recommended.");
+				repository.discardChanges();
+				return;
+			}
+
+			LOGGER.info("Starting block archiver from height {}...", startHeight);
+
+			while (!Controller.isStopping()) {
+				repository.discardChanges();
+
+				Thread.sleep(Settings.getInstance().getArchiveInterval());
+
+				BlockData chainTip = Controller.getInstance().getChainTip();
+				if (chainTip == null || NTP.getTime() == null) {
+					continue;
+				}
+
+				// Don't even attempt if we're mid-sync as our repository requests will be delayed for ages
+				if (Controller.getInstance().isSynchronizing()) {
+					continue;
+				}
+
+				// Don't attempt to archive if we're not synced yet
+				final Long minLatestBlockTimestamp = Controller.getMinimumLatestBlockTimestamp();
+				if (minLatestBlockTimestamp == null || chainTip.getTimestamp() < minLatestBlockTimestamp) {
+					continue;
+				}
+
+
+				// Build cache of blocks
+				try {
+					final int maximumArchiveHeight = BlockArchiveWriter.getMaxArchiveHeight(repository);
+					BlockArchiveWriter writer = new BlockArchiveWriter(startHeight, maximumArchiveHeight, repository);
+					BlockArchiveWriter.BlockArchiveWriteResult result = writer.write();
+					switch (result) {
+						case OK:
+							// Increment block archive height
+							startHeight += writer.getWrittenCount();
+							repository.getBlockArchiveRepository().setBlockArchiveHeight(startHeight);
+							repository.saveChanges();
+							break;
+
+						case STOPPING:
+							return;
+
+							// We've reached the limit of the blocks we can archive
+							// Sleep for a while to allow more to become available
+						case NOT_ENOUGH_BLOCKS:
+							// We didn't reach our file size target, so that must mean that we don't have enough blocks
+							// yet or something went wrong. Sleep for a while and then try again.
+							repository.discardChanges();
+							Thread.sleep(60 * 60 * 1000L); // 1 hour
+							break;
+
+						case BLOCK_NOT_FOUND:
+							// We tried to archive a block that didn't exist. This is a major failure and likely means
+							// that a bootstrap or re-sync is needed. Try again every minute until then.
+							LOGGER.info("Error: block not found when building archive. If this error persists, " +
+									"a bootstrap or re-sync may be needed.");
+							repository.discardChanges();
+							Thread.sleep( 60 * 1000L); // 1 minute
+							break;
+					}
+
+				} catch (IOException | TransformationException e) {
+					LOGGER.info("Caught exception when creating block cache", e);
+				}
+
+			}
+		} catch (DataException e) {
+			LOGGER.info("Caught exception when creating block cache", e);
+		} catch (InterruptedException e) {
+			// Do nothing
+		}
+
+	}
+
+}

src/main/java/org/qortal/controller/repository/BlockPruner.java

@@ -0,0 +1,114 @@
+package org.qortal.controller.repository;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.controller.Controller;
+import org.qortal.data.block.BlockData;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+import org.qortal.settings.Settings;
+import org.qortal.utils.NTP;
+
+public class BlockPruner implements Runnable {
+
+	private static final Logger LOGGER = LogManager.getLogger(BlockPruner.class);
+
+	@Override
+	public void run() {
+		Thread.currentThread().setName("Block pruner");
+
+		boolean archiveMode = false;
+		if (!Settings.getInstance().isTopOnly()) {
+			// Top-only mode isn't enabled, but we might want to prune for the purposes of archiving
+			if (!Settings.getInstance().isArchiveEnabled()) {
+				// No pruning or archiving, so we must not prune anything
+				return;
+			}
+			else {
+				// We're allowed to prune blocks that have already been archived
+				archiveMode = true;
+			}
+		}
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			int pruneStartHeight = repository.getBlockRepository().getBlockPruneHeight();
+
+			// Don't attempt to prune if we have no ATStatesHeightIndex, as it will be too slow
+			boolean hasAtStatesHeightIndex = repository.getATRepository().hasAtStatesHeightIndex();
+			if (!hasAtStatesHeightIndex) {
+				LOGGER.info("Unable to start block pruner due to missing ATStatesHeightIndex. Bootstrapping is recommended.");
+				return;
+			}
+
+			while (!Controller.isStopping()) {
+				repository.discardChanges();
+
+				Thread.sleep(Settings.getInstance().getBlockPruneInterval());
+
+				BlockData chainTip = Controller.getInstance().getChainTip();
+				if (chainTip == null || NTP.getTime() == null)
+					continue;
+
+				// Don't even attempt if we're mid-sync as our repository requests will be delayed for ages
+				if (Controller.getInstance().isSynchronizing()) {
+					continue;
+				}
+
+				// Don't attempt to prune if we're not synced yet
+				final Long minLatestBlockTimestamp = Controller.getMinimumLatestBlockTimestamp();
+				if (minLatestBlockTimestamp == null || chainTip.getTimestamp() < minLatestBlockTimestamp) {
+					continue;
+				}
+
+				// Prune all blocks up until our latest minus pruneBlockLimit
+				final int ourLatestHeight = chainTip.getHeight();
+				int upperPrunableHeight = ourLatestHeight - Settings.getInstance().getPruneBlockLimit();
+
+				// In archive mode we are only allowed to trim blocks that have already been archived
+				if (archiveMode) {
+					upperPrunableHeight = repository.getBlockArchiveRepository().getBlockArchiveHeight() - 1;
+				}
+
+				int upperBatchHeight = pruneStartHeight + Settings.getInstance().getBlockPruneBatchSize();
+				int upperPruneHeight = Math.min(upperBatchHeight, upperPrunableHeight);
+
+				if (pruneStartHeight >= upperPruneHeight) {
+					continue;
+				}
+
+				LOGGER.debug(String.format("Pruning blocks between %d and %d...", pruneStartHeight, upperPruneHeight));
+
+				int numBlocksPruned = repository.getBlockRepository().pruneBlocks(pruneStartHeight, upperPruneHeight);
+				repository.saveChanges();
+
+				if (numBlocksPruned > 0) {
+					LOGGER.debug(String.format("Pruned %d block%s between %d and %d",
+							numBlocksPruned, (numBlocksPruned != 1 ? "s" : ""),
+							pruneStartHeight, upperPruneHeight));
+				} else {
+					final int nextPruneHeight = upperPruneHeight + 1;
+					repository.getBlockRepository().setBlockPruneHeight(nextPruneHeight);
+					repository.saveChanges();
+					LOGGER.debug(String.format("Bumping block base prune height to %d", pruneStartHeight));
+
+					// Can we move onto next batch?
+					if (upperPrunableHeight > nextPruneHeight) {
+						pruneStartHeight = nextPruneHeight;
+					}
+					else {
+						// We've pruned up to the upper prunable height
+						// Back off for a while to save CPU for syncing
+						repository.discardChanges();
+						Thread.sleep(10*60*1000L);
+					}
+				}
+			}
+		} catch (DataException e) {
+			LOGGER.warn(String.format("Repository issue trying to prune blocks: %s", e.getMessage()));
+		} catch (InterruptedException e) {
+			// Time to exit
+		}
+	}
+
+}

src/main/java/org/qortal/controller/repository/NamesDatabaseIntegrityCheck.java

@@ -0,0 +1,410 @@
+package org.qortal.controller.repository;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.account.PublicKeyAccount;
+import org.qortal.api.resource.TransactionsResource.ConfirmationStatus;
+import org.qortal.data.naming.NameData;
+import org.qortal.data.transaction.*;
+import org.qortal.naming.Name;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+import org.qortal.transaction.Transaction.TransactionType;
+import org.qortal.utils.Unicode;
+
+import java.util.*;
+
+public class NamesDatabaseIntegrityCheck {
+
+    private static final Logger LOGGER = LogManager.getLogger(NamesDatabaseIntegrityCheck.class);
+
+    private static final List<TransactionType> ALL_NAME_TX_TYPE = Arrays.asList(
+            TransactionType.REGISTER_NAME,
+            TransactionType.UPDATE_NAME,
+            TransactionType.BUY_NAME,
+            TransactionType.SELL_NAME
+    );
+
+    private List<TransactionData> nameTransactions = new ArrayList<>();
+
+    public int rebuildName(String name, Repository repository) {
+        int modificationCount = 0;
+        try {
+            List<TransactionData> transactions = this.fetchAllTransactionsInvolvingName(name, repository);
+            if (transactions.isEmpty()) {
+                // This name was never registered, so there's nothing to do
+                return modificationCount;
+            }
+
+            // Loop through each past transaction and re-apply it to the Names table
+            for (TransactionData currentTransaction : transactions) {
+
+                // Process REGISTER_NAME transactions
+                if (currentTransaction.getType() == TransactionType.REGISTER_NAME) {
+                    RegisterNameTransactionData registerNameTransactionData = (RegisterNameTransactionData) currentTransaction;
+                    Name nameObj = new Name(repository, registerNameTransactionData);
+                    nameObj.register();
+                    modificationCount++;
+                    LOGGER.trace("Processed REGISTER_NAME transaction for name {}", name);
+                }
+
+                // Process UPDATE_NAME transactions
+                if (currentTransaction.getType() == TransactionType.UPDATE_NAME) {
+                    UpdateNameTransactionData updateNameTransactionData = (UpdateNameTransactionData) currentTransaction;
+
+                    if (Objects.equals(updateNameTransactionData.getNewName(), name) &&
+                            !Objects.equals(updateNameTransactionData.getName(), updateNameTransactionData.getNewName())) {
+                        // This renames an existing name, so we need to process that instead
+                        this.rebuildName(updateNameTransactionData.getName(), repository);
+                    }
+                    else {
+                        Name nameObj = new Name(repository, name);
+                        if (nameObj != null && nameObj.getNameData() != null) {
+                            nameObj.update(updateNameTransactionData);
+                            modificationCount++;
+                            LOGGER.trace("Processed UPDATE_NAME transaction for name {}", name);
+                        } else {
+                            // Something went wrong
+                            throw new DataException(String.format("Name data not found for name %s", updateNameTransactionData.getName()));
+                        }
+                    }
+                }
+
+                // Process SELL_NAME transactions
+                if (currentTransaction.getType() == TransactionType.SELL_NAME) {
+                    SellNameTransactionData sellNameTransactionData = (SellNameTransactionData) currentTransaction;
+                    Name nameObj = new Name(repository, sellNameTransactionData.getName());
+                    if (nameObj != null && nameObj.getNameData() != null) {
+                        nameObj.sell(sellNameTransactionData);
+                        modificationCount++;
+                        LOGGER.trace("Processed SELL_NAME transaction for name {}", name);
+                    }
+                    else {
+                        // Something went wrong
+                        throw new DataException(String.format("Name data not found for name %s", sellNameTransactionData.getName()));
+                    }
+                }
+
+                // Process BUY_NAME transactions
+                if (currentTransaction.getType() == TransactionType.BUY_NAME) {
+                    BuyNameTransactionData buyNameTransactionData = (BuyNameTransactionData) currentTransaction;
+                    Name nameObj = new Name(repository, buyNameTransactionData.getName());
+                    if (nameObj != null && nameObj.getNameData() != null) {
+                        nameObj.buy(buyNameTransactionData);
+                        modificationCount++;
+                        LOGGER.trace("Processed BUY_NAME transaction for name {}", name);
+                    }
+                    else {
+                        // Something went wrong
+                        throw new DataException(String.format("Name data not found for name %s", buyNameTransactionData.getName()));
+                    }
+                }
+            }
+
+        } catch (DataException e) {
+            LOGGER.info("Unable to run integrity check for name {}: {}", name, e.getMessage());
+        }
+
+        return modificationCount;
+    }
+
+    public int rebuildAllNames() {
+        int modificationCount = 0;
+        try (final Repository repository = RepositoryManager.getRepository()) {
+            List<String> names = this.fetchAllNames(repository);
+            for (String name : names) {
+                modificationCount += this.rebuildName(name, repository);
+            }
+            repository.saveChanges();
+        }
+        catch (DataException e) {
+            LOGGER.info("Error when running integrity check for all names: {}", e.getMessage());
+        }
+
+        //LOGGER.info("modificationCount: {}", modificationCount);
+        return modificationCount;
+    }
+
+    public void runIntegrityCheck() {
+        boolean integrityCheckFailed = false;
+        try (final Repository repository = RepositoryManager.getRepository()) {
+
+            // Fetch all the (confirmed) REGISTER_NAME transactions
+            List<RegisterNameTransactionData> registerNameTransactions = this.fetchRegisterNameTransactions();
+
+            // Loop through each REGISTER_NAME txn signature and request the full transaction data
+            for (RegisterNameTransactionData registerNameTransactionData : registerNameTransactions) {
+                String registeredName = registerNameTransactionData.getName();
+                NameData nameData = repository.getNameRepository().fromName(registeredName);
+
+                // Check to see if this name has been updated or bought at any point
+                TransactionData latestUpdate = this.fetchLatestModificationTransactionInvolvingName(registeredName, repository);
+                if (latestUpdate == null) {
+                    // Name was never updated once registered
+                    // We expect this name to still be registered to this transaction's creator
+
+                    if (nameData == null) {
+                        LOGGER.info("Error: registered name {} doesn't exist in Names table. Adding...", registeredName);
+                        integrityCheckFailed = true;
+                    }
+                    else {
+                        LOGGER.trace("Registered name {} is correctly registered", registeredName);
+                    }
+
+                    // Check the owner is correct
+                    PublicKeyAccount creator = new PublicKeyAccount(repository, registerNameTransactionData.getCreatorPublicKey());
+                    if (!Objects.equals(creator.getAddress(), nameData.getOwner())) {
+                        LOGGER.info("Error: registered name {} is owned by {}, but it should be {}",
+                                registeredName, nameData.getOwner(), creator.getAddress());
+                        integrityCheckFailed = true;
+                    }
+                    else {
+                        LOGGER.trace("Registered name {} has the correct owner", registeredName);
+                    }
+                }
+                else {
+                    // Check if owner is correct after update
+
+                    // Check for name updates
+                    if (latestUpdate.getType() == TransactionType.UPDATE_NAME) {
+                        UpdateNameTransactionData updateNameTransactionData = (UpdateNameTransactionData) latestUpdate;
+                        PublicKeyAccount creator = new PublicKeyAccount(repository, updateNameTransactionData.getCreatorPublicKey());
+
+                        // When this name is the "new name", we expect the current owner to match the txn creator
+                        if (Objects.equals(updateNameTransactionData.getNewName(), registeredName)) {
+                            if (!Objects.equals(creator.getAddress(), nameData.getOwner())) {
+                                LOGGER.info("Error: registered name {} is owned by {}, but it should be {}",
+                                        registeredName, nameData.getOwner(), creator.getAddress());
+                                integrityCheckFailed = true;
+                            }
+                            else {
+                                LOGGER.trace("Registered name {} has the correct owner after being updated", registeredName);
+                            }
+                        }
+
+                        // When this name is the old name, we expect the "new name"'s owner to match the txn creator
+                        // The old name will then be unregistered, or re-registered.
+                        // FUTURE: check database integrity for names that have been updated and then the original name re-registered
+                        else if (Objects.equals(updateNameTransactionData.getName(), registeredName)) {
+                            NameData newNameData = repository.getNameRepository().fromName(updateNameTransactionData.getNewName());
+                            if (!Objects.equals(creator.getAddress(), newNameData.getOwner())) {
+                                LOGGER.info("Error: registered name {} is owned by {}, but it should be {}",
+                                        updateNameTransactionData.getNewName(), newNameData.getOwner(), creator.getAddress());
+                                integrityCheckFailed = true;
+                            }
+                            else {
+                                LOGGER.trace("Registered name {} has the correct owner after being updated", updateNameTransactionData.getNewName());
+                            }
+                        }
+
+                        else {
+                            LOGGER.info("Unhandled update case for name {}", registeredName);
+                        }
+                    }
+
+                    // Check for name buys
+                    else if (latestUpdate.getType() == TransactionType.BUY_NAME) {
+                        BuyNameTransactionData buyNameTransactionData = (BuyNameTransactionData) latestUpdate;
+                        PublicKeyAccount creator = new PublicKeyAccount(repository, buyNameTransactionData.getCreatorPublicKey());
+                        if (!Objects.equals(creator.getAddress(), nameData.getOwner())) {
+                            LOGGER.info("Error: registered name {} is owned by {}, but it should be {}",
+                                    registeredName, nameData.getOwner(), creator.getAddress());
+                            integrityCheckFailed = true;
+                        }
+                        else {
+                            LOGGER.trace("Registered name {} has the correct owner after being bought", registeredName);
+                        }
+                    }
+
+                    // Check for name sells
+                    else if (latestUpdate.getType() == TransactionType.SELL_NAME) {
+                        SellNameTransactionData sellNameTransactionData = (SellNameTransactionData) latestUpdate;
+                        PublicKeyAccount creator = new PublicKeyAccount(repository, sellNameTransactionData.getCreatorPublicKey());
+                        if (!Objects.equals(creator.getAddress(), nameData.getOwner())) {
+                            LOGGER.info("Error: registered name {} is owned by {}, but it should be {}",
+                                    registeredName, nameData.getOwner(), creator.getAddress());
+                            integrityCheckFailed = true;
+                        }
+                        else {
+                            LOGGER.trace("Registered name {} has the correct owner after being listed for sale", registeredName);
+                        }
+                    }
+
+                    else {
+                        LOGGER.info("Unhandled case for name {}", registeredName);
+                    }
+
+                }
+
+            }
+
+        } catch (DataException e) {
+            LOGGER.warn(String.format("Repository issue trying to trim online accounts signatures: %s", e.getMessage()));
+            integrityCheckFailed = true;
+        }
+
+        if (integrityCheckFailed) {
+            LOGGER.info("Registered names database integrity check failed. Bootstrapping is recommended.");
+        } else {
+            LOGGER.info("Registered names database integrity check passed.");
+        }
+    }
+
+    private List<RegisterNameTransactionData> fetchRegisterNameTransactions() {
+        List<RegisterNameTransactionData> registerNameTransactions = new ArrayList<>();
+
+        for (TransactionData transactionData : this.nameTransactions) {
+            if (transactionData.getType() == TransactionType.REGISTER_NAME) {
+                RegisterNameTransactionData registerNameTransactionData = (RegisterNameTransactionData) transactionData;
+                registerNameTransactions.add(registerNameTransactionData);
+            }
+        }
+        return registerNameTransactions;
+    }
+
+    private List<UpdateNameTransactionData> fetchUpdateNameTransactions() {
+        List<UpdateNameTransactionData> updateNameTransactions = new ArrayList<>();
+
+        for (TransactionData transactionData : this.nameTransactions) {
+            if (transactionData.getType() == TransactionType.UPDATE_NAME) {
+                UpdateNameTransactionData updateNameTransactionData = (UpdateNameTransactionData) transactionData;
+                updateNameTransactions.add(updateNameTransactionData);
+            }
+        }
+        return updateNameTransactions;
+    }
+
+    private List<SellNameTransactionData> fetchSellNameTransactions() {
+        List<SellNameTransactionData> sellNameTransactions = new ArrayList<>();
+
+        for (TransactionData transactionData : this.nameTransactions) {
+            if (transactionData.getType() == TransactionType.SELL_NAME) {
+                SellNameTransactionData sellNameTransactionData = (SellNameTransactionData) transactionData;
+                sellNameTransactions.add(sellNameTransactionData);
+            }
+        }
+        return sellNameTransactions;
+    }
+
+    private List<BuyNameTransactionData> fetchBuyNameTransactions() {
+        List<BuyNameTransactionData> buyNameTransactions = new ArrayList<>();
+
+        for (TransactionData transactionData : this.nameTransactions) {
+            if (transactionData.getType() == TransactionType.BUY_NAME) {
+                BuyNameTransactionData buyNameTransactionData = (BuyNameTransactionData) transactionData;
+                buyNameTransactions.add(buyNameTransactionData);
+            }
+        }
+        return buyNameTransactions;
+    }
+
+    private void fetchAllNameTransactions(Repository repository) throws DataException {
+        List<TransactionData> nameTransactions = new ArrayList<>();
+
+        // Fetch all the confirmed REGISTER_NAME transaction signatures
+        List<byte[]> signatures = repository.getTransactionRepository().getSignaturesMatchingCriteria(
+                null, null, null, ALL_NAME_TX_TYPE, null, null,
+                ConfirmationStatus.CONFIRMED, null, null, false);
+
+        for (byte[] signature : signatures) {
+            TransactionData transactionData = repository.getTransactionRepository().fromSignature(signature);
+            nameTransactions.add(transactionData);
+        }
+        this.nameTransactions = nameTransactions;
+    }
+
+    private List<TransactionData> fetchAllTransactionsInvolvingName(String name, Repository repository) throws DataException {
+        List<TransactionData> transactions = new ArrayList<>();
+        String reducedName = Unicode.sanitize(name);
+
+        // Fetch all the confirmed name-modification transactions
+        if (this.nameTransactions.isEmpty()) {
+            this.fetchAllNameTransactions(repository);
+        }
+
+        for (TransactionData transactionData : this.nameTransactions) {
+
+            if ((transactionData instanceof RegisterNameTransactionData)) {
+                RegisterNameTransactionData registerNameTransactionData = (RegisterNameTransactionData) transactionData;
+                if (Objects.equals(registerNameTransactionData.getReducedName(), reducedName)) {
+                    transactions.add(transactionData);
+                }
+            }
+            if ((transactionData instanceof UpdateNameTransactionData)) {
+                UpdateNameTransactionData updateNameTransactionData = (UpdateNameTransactionData) transactionData;
+                if (Objects.equals(updateNameTransactionData.getName(), name) ||
+                        Objects.equals(updateNameTransactionData.getReducedNewName(), reducedName)) {
+                    transactions.add(transactionData);
+                }
+            }
+            if ((transactionData instanceof BuyNameTransactionData)) {
+                BuyNameTransactionData buyNameTransactionData = (BuyNameTransactionData) transactionData;
+                if (Objects.equals(buyNameTransactionData.getName(), name)) {
+                    transactions.add(transactionData);
+                }
+            }
+            if ((transactionData instanceof SellNameTransactionData)) {
+                SellNameTransactionData sellNameTransactionData = (SellNameTransactionData) transactionData;
+                if (Objects.equals(sellNameTransactionData.getName(), name)) {
+                    transactions.add(transactionData);
+                }
+            }
+        }
+        return transactions;
+    }
+
+    private TransactionData fetchLatestModificationTransactionInvolvingName(String registeredName, Repository repository) throws DataException {
+        List<TransactionData> transactionsInvolvingName = this.fetchAllTransactionsInvolvingName(registeredName, repository);
+
+        // Get the latest update for this name (excluding REGISTER_NAME transactions)
+        TransactionData latestUpdateToName = transactionsInvolvingName.stream()
+                .filter(txn -> txn.getType() != TransactionType.REGISTER_NAME)
+                .max(Comparator.comparing(TransactionData::getTimestamp))
+                .orElse(null);
+
+        return latestUpdateToName;
+    }
+
+    private List<String> fetchAllNames(Repository repository) throws DataException {
+        List<String> names = new ArrayList<>();
+
+        // Fetch all the confirmed name transactions
+        if (this.nameTransactions.isEmpty()) {
+            this.fetchAllNameTransactions(repository);
+        }
+
+        for (TransactionData transactionData : this.nameTransactions) {
+
+            if ((transactionData instanceof RegisterNameTransactionData)) {
+                RegisterNameTransactionData registerNameTransactionData = (RegisterNameTransactionData) transactionData;
+                if (!names.contains(registerNameTransactionData.getName())) {
+                    names.add(registerNameTransactionData.getName());
+                }
+            }
+            if ((transactionData instanceof UpdateNameTransactionData)) {
+                UpdateNameTransactionData updateNameTransactionData = (UpdateNameTransactionData) transactionData;
+                if (!names.contains(updateNameTransactionData.getName())) {
+                    names.add(updateNameTransactionData.getName());
+                }
+                if (!names.contains(updateNameTransactionData.getNewName())) {
+                    names.add(updateNameTransactionData.getNewName());
+                }
+            }
+            if ((transactionData instanceof BuyNameTransactionData)) {
+                BuyNameTransactionData buyNameTransactionData = (BuyNameTransactionData) transactionData;
+                if (!names.contains(buyNameTransactionData.getName())) {
+                    names.add(buyNameTransactionData.getName());
+                }
+            }
+            if ((transactionData instanceof SellNameTransactionData)) {
+                SellNameTransactionData sellNameTransactionData = (SellNameTransactionData) transactionData;
+                if (!names.contains(sellNameTransactionData.getName())) {
+                    names.add(sellNameTransactionData.getName());
+                }
+            }
+        }
+        return names;
+    }
+
+}

src/main/java/org/qortal/controller/repository/OnlineAccountsSignaturesTrimmer.java

@@ -1,8 +1,9 @@
-package org.qortal.controller;
+package org.qortal.controller.repository;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.qortal.block.BlockChain;
+import org.qortal.controller.Controller;
 import org.qortal.data.block.BlockData;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;

src/main/java/org/qortal/controller/repository/PruneManager.java

@@ -0,0 +1,160 @@
+package org.qortal.controller.repository;
+
+import org.apache.commons.io.FileUtils;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.controller.Controller;
+
+import org.qortal.data.block.BlockData;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.settings.Settings;
+import org.qortal.utils.DaemonThreadFactory;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+public class PruneManager {
+
+    private static final Logger LOGGER = LogManager.getLogger(PruneManager.class);
+
+    private static PruneManager instance;
+
+    private boolean isTopOnly = Settings.getInstance().isTopOnly();
+    private int pruneBlockLimit = Settings.getInstance().getPruneBlockLimit();
+
+    private ExecutorService executorService;
+
+    private PruneManager() {
+
+    }
+
+    public static synchronized PruneManager getInstance() {
+        if (instance == null)
+            instance = new PruneManager();
+
+        return instance;
+    }
+
+    public void start() {
+        this.executorService = Executors.newCachedThreadPool(new DaemonThreadFactory());
+
+        if (Settings.getInstance().isTopOnly()) {
+            // Top-only-sync
+            this.startTopOnlySyncMode();
+        }
+        else if (Settings.getInstance().isArchiveEnabled()) {
+            // Full node with block archive
+            this.startFullNodeWithBlockArchive();
+        }
+        else {
+            // Full node with full SQL support
+            this.startFullSQLNode();
+        }
+    }
+
+    /**
+     * Top-only-sync
+     * In this mode, we delete (prune) all blocks except
+     * a small number of recent ones. There is no need for
+     * trimming or archiving, because all relevant blocks
+     * are deleted.
+     */
+    private void startTopOnlySyncMode() {
+        this.startPruning();
+
+        // We don't need the block archive in top-only mode
+        this.deleteArchive();
+    }
+
+    /**
+     * Full node with block archive
+     * In this mode we archive trimmed blocks, and then
+     * prune archived blocks to keep the database small
+     */
+    private void startFullNodeWithBlockArchive() {
+        this.startTrimming();
+        this.startArchiving();
+        this.startPruning();
+    }
+
+    /**
+     * Full node with full SQL support
+     * In this mode we trim the database but don't prune
+     * or archive any data, because we want to maintain
+     * full SQL support of old blocks. This mode will not
+     * be actively maintained but can be used by those who
+     * need to perform SQL analysis on older blocks.
+     */
+    private void startFullSQLNode() {
+        this.startTrimming();
+    }
+
+
+    private void startPruning() {
+        this.executorService.execute(new AtStatesPruner());
+        this.executorService.execute(new BlockPruner());
+    }
+
+    private void startTrimming() {
+        this.executorService.execute(new AtStatesTrimmer());
+        this.executorService.execute(new OnlineAccountsSignaturesTrimmer());
+    }
+
+    private void startArchiving() {
+        this.executorService.execute(new BlockArchiver());
+    }
+
+    private void deleteArchive() {
+        if (!Settings.getInstance().isTopOnly()) {
+            LOGGER.error("Refusing to delete archive when not in top-only mode");
+        }
+
+        try {
+            Path archivePath = Paths.get(Settings.getInstance().getRepositoryPath(), "archive");
+            if (archivePath.toFile().exists()) {
+                LOGGER.info("Deleting block archive because we are in top-only mode...");
+                FileUtils.deleteDirectory(archivePath.toFile());
+            }
+
+        } catch (IOException e) {
+            LOGGER.info("Couldn't delete archive: {}", e.getMessage());
+        }
+    }
+
+    public void stop() {
+        this.executorService.shutdownNow();
+
+        try {
+            this.executorService.awaitTermination(2L, TimeUnit.SECONDS);
+        } catch (InterruptedException e) {
+            // We tried...
+        }
+    }
+
+    public boolean isBlockPruned(int height) throws DataException {
+        if (!this.isTopOnly) {
+            return false;
+        }
+
+        BlockData chainTip = Controller.getInstance().getChainTip();
+        if (chainTip == null) {
+            throw new DataException("Unable to determine chain tip when checking if a block is pruned");
+        }
+
+        if (height == 1) {
+            // We don't prune the genesis block
+            return false;
+        }
+
+        final int ourLatestHeight = chainTip.getHeight();
+        final int latestUnprunedHeight = ourLatestHeight - this.pruneBlockLimit;
+
+        return (height < latestUnprunedHeight);
+    }
+
+}

src/main/java/org/qortal/controller/tradebot/BitcoinACCTv1TradeBot.java

@@ -360,6 +360,7 @@ public class BitcoinACCTv1TradeBot implements AcctTradeBot {
 			case BOB_DONE:
 			case ALICE_REFUNDED:
 			case BOB_REFUNDED:
+			case ALICE_REFUNDING_A:
 				return true;
 
 			default:

src/main/java/org/qortal/controller/tradebot/DogecoinACCTv1TradeBot.java

@@ -201,7 +201,7 @@ public class DogecoinACCTv1TradeBot implements AcctTradeBot {
 		TradeBot.updateTradeBotState(repository, tradeBotData, () -> String.format("Built AT %s. Waiting for deployment", atAddress));
 
 		// Attempt to backup the trade bot data
-		TradeBot.backupTradeBotData(repository);
+		TradeBot.backupTradeBotData(repository, null);
 
 		// Return to user for signing and broadcast as we don't have their Qortal private key
 		try {
@@ -276,7 +276,8 @@ public class DogecoinACCTv1TradeBot implements AcctTradeBot {
 				crossChainTradeData.expectedForeignAmount, xprv58, null, lockTimeA, receivingPublicKeyHash);
 
 		// Attempt to backup the trade bot data
-		TradeBot.backupTradeBotData(repository);
+		// Include tradeBotData as an additional parameter, since it's not in the repository yet
+		TradeBot.backupTradeBotData(repository, Arrays.asList(tradeBotData));
 
 		// Check we have enough funds via xprv58 to fund P2SH to cover expectedForeignAmount
 		long p2shFee;
@@ -353,6 +354,7 @@ public class DogecoinACCTv1TradeBot implements AcctTradeBot {
 			case BOB_DONE:
 			case ALICE_REFUNDED:
 			case BOB_REFUNDED:
+			case ALICE_REFUNDING_A:
 				return true;
 
 			default:

src/main/java/org/qortal/controller/tradebot/DogecoinACCTv2TradeBot.java

@@ -0,0 +1,884 @@
+package org.qortal.controller.tradebot;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.bitcoinj.core.*;
+import org.bitcoinj.script.Script.ScriptType;
+import org.qortal.account.PrivateKeyAccount;
+import org.qortal.account.PublicKeyAccount;
+import org.qortal.api.model.crosschain.TradeBotCreateRequest;
+import org.qortal.asset.Asset;
+import org.qortal.crosschain.*;
+import org.qortal.crypto.Crypto;
+import org.qortal.data.at.ATData;
+import org.qortal.data.crosschain.CrossChainTradeData;
+import org.qortal.data.crosschain.TradeBotData;
+import org.qortal.data.transaction.BaseTransactionData;
+import org.qortal.data.transaction.DeployAtTransactionData;
+import org.qortal.data.transaction.MessageTransactionData;
+import org.qortal.group.Group;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.transaction.DeployAtTransaction;
+import org.qortal.transaction.MessageTransaction;
+import org.qortal.transaction.Transaction.ValidationResult;
+import org.qortal.transform.TransformationException;
+import org.qortal.transform.transaction.DeployAtTransactionTransformer;
+import org.qortal.utils.Base58;
+import org.qortal.utils.NTP;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import static java.util.Arrays.stream;
+import static java.util.stream.Collectors.toMap;
+
+/**
+ * Performing cross-chain trading steps on behalf of user.
+ * <p>
+ * We deal with three different independent state-spaces here:
+ * <ul>
+ * 	<li>Qortal blockchain</li>
+ * 	<li>Foreign blockchain</li>
+ * 	<li>Trade-bot entries</li>
+ * </ul>
+ */
+public class DogecoinACCTv2TradeBot implements AcctTradeBot {
+
+	private static final Logger LOGGER = LogManager.getLogger(DogecoinACCTv2TradeBot.class);
+
+	public enum State implements TradeBot.StateNameAndValueSupplier {
+		BOB_WAITING_FOR_AT_CONFIRM(10, false, false),
+		BOB_WAITING_FOR_MESSAGE(15, true, true),
+		BOB_WAITING_FOR_AT_REDEEM(25, true, true),
+		BOB_DONE(30, false, false),
+		BOB_REFUNDED(35, false, false),
+
+		ALICE_WAITING_FOR_AT_LOCK(85, true, true),
+		ALICE_DONE(95, false, false),
+		ALICE_REFUNDING_A(105, true, true),
+		ALICE_REFUNDED(110, false, false);
+
+		private static final Map<Integer, State> map = stream(State.values()).collect(toMap(state -> state.value, state -> state));
+
+		public final int value;
+		public final boolean requiresAtData;
+		public final boolean requiresTradeData;
+
+		State(int value, boolean requiresAtData, boolean requiresTradeData) {
+			this.value = value;
+			this.requiresAtData = requiresAtData;
+			this.requiresTradeData = requiresTradeData;
+		}
+
+		public static State valueOf(int value) {
+			return map.get(value);
+		}
+
+		@Override
+		public String getState() {
+			return this.name();
+		}
+
+		@Override
+		public int getStateValue() {
+			return this.value;
+		}
+	}
+
+	/** Maximum time Bob waits for his AT creation transaction to be confirmed into a block. (milliseconds) */
+	private static final long MAX_AT_CONFIRMATION_PERIOD = 24 * 60 * 60 * 1000L; // ms
+
+	private static DogecoinACCTv2TradeBot instance;
+
+	private final List<String> endStates = Arrays.asList(State.BOB_DONE, State.BOB_REFUNDED, State.ALICE_DONE, State.ALICE_REFUNDING_A, State.ALICE_REFUNDED).stream()
+			.map(State::name)
+			.collect(Collectors.toUnmodifiableList());
+
+	private DogecoinACCTv2TradeBot() {
+	}
+
+	public static synchronized DogecoinACCTv2TradeBot getInstance() {
+		if (instance == null)
+			instance = new DogecoinACCTv2TradeBot();
+
+		return instance;
+	}
+
+	@Override
+	public List<String> getEndStates() {
+		return this.endStates;
+	}
+
+	/**
+	 * Creates a new trade-bot entry from the "Bob" viewpoint, i.e. OFFERing QORT in exchange for DOGE.
+	 * <p>
+	 * Generates:
+	 * <ul>
+	 * 	<li>new 'trade' private key</li>
+	 * </ul>
+	 * Derives:
+	 * <ul>
+	 * 	<li>'native' (as in Qortal) public key, public key hash, address (starting with Q)</li>
+	 * 	<li>'foreign' (as in Dogecoin) public key, public key hash</li>
+	 * </ul>
+	 * A Qortal AT is then constructed including the following as constants in the 'data segment':
+	 * <ul>
+	 * 	<li>'native'/Qortal 'trade' address - used as a MESSAGE contact</li>
+	 * 	<li>'foreign'/Dogecoin public key hash - used by Alice's P2SH scripts to allow redeem</li>
+	 * 	<li>QORT amount on offer by Bob</li>
+	 * 	<li>DOGE amount expected in return by Bob (from Alice)</li>
+	 * 	<li>trading timeout, in case things go wrong and everyone needs to refund</li>
+	 * </ul>
+	 * Returns a DEPLOY_AT transaction that needs to be signed and broadcast to the Qortal network.
+	 * <p>
+	 * Trade-bot will wait for Bob's AT to be deployed before taking next step.
+	 * <p>
+	 * @param repository
+	 * @param tradeBotCreateRequest
+	 * @return raw, unsigned DEPLOY_AT transaction
+	 * @throws DataException
+	 */
+	public byte[] createTrade(Repository repository, TradeBotCreateRequest tradeBotCreateRequest) throws DataException {
+		byte[] tradePrivateKey = TradeBot.generateTradePrivateKey();
+
+		byte[] tradeNativePublicKey = TradeBot.deriveTradeNativePublicKey(tradePrivateKey);
+		byte[] tradeNativePublicKeyHash = Crypto.hash160(tradeNativePublicKey);
+		String tradeNativeAddress = Crypto.toAddress(tradeNativePublicKey);
+
+		byte[] tradeForeignPublicKey = TradeBot.deriveTradeForeignPublicKey(tradePrivateKey);
+		byte[] tradeForeignPublicKeyHash = Crypto.hash160(tradeForeignPublicKey);
+
+		// Convert Dogecoin receiving address into public key hash (we only support P2PKH at this time)
+		Address dogecoinReceivingAddress;
+		try {
+			dogecoinReceivingAddress = Address.fromString(Dogecoin.getInstance().getNetworkParameters(), tradeBotCreateRequest.receivingAddress);
+		} catch (AddressFormatException e) {
+			throw new DataException("Unsupported Dogecoin receiving address: " + tradeBotCreateRequest.receivingAddress);
+		}
+		if (dogecoinReceivingAddress.getOutputScriptType() != ScriptType.P2PKH)
+			throw new DataException("Unsupported Dogecoin receiving address: " + tradeBotCreateRequest.receivingAddress);
+
+		byte[] dogecoinReceivingAccountInfo = dogecoinReceivingAddress.getHash();
+
+		PublicKeyAccount creator = new PublicKeyAccount(repository, tradeBotCreateRequest.creatorPublicKey);
+
+		// Deploy AT
+		long timestamp = NTP.getTime();
+		byte[] reference = creator.getLastReference();
+		long fee = 0L;
+		byte[] signature = null;
+		BaseTransactionData baseTransactionData = new BaseTransactionData(timestamp, Group.NO_GROUP, reference, creator.getPublicKey(), fee, signature);
+
+		String name = "QORT/DOGE ACCT";
+		String description = "QORT/DOGE cross-chain trade";
+		String aTType = "ACCT";
+		String tags = "ACCT QORT DOGE";
+		byte[] creationBytes = DogecoinACCTv2.buildQortalAT(tradeNativeAddress, tradeForeignPublicKeyHash, tradeBotCreateRequest.qortAmount,
+				tradeBotCreateRequest.foreignAmount, tradeBotCreateRequest.tradeTimeout);
+		long amount = tradeBotCreateRequest.fundingQortAmount;
+
+		DeployAtTransactionData deployAtTransactionData = new DeployAtTransactionData(baseTransactionData, name, description, aTType, tags, creationBytes, amount, Asset.QORT);
+
+		DeployAtTransaction deployAtTransaction = new DeployAtTransaction(repository, deployAtTransactionData);
+		fee = deployAtTransaction.calcRecommendedFee();
+		deployAtTransactionData.setFee(fee);
+
+		DeployAtTransaction.ensureATAddress(deployAtTransactionData);
+		String atAddress = deployAtTransactionData.getAtAddress();
+
+		TradeBotData tradeBotData =  new TradeBotData(tradePrivateKey, DogecoinACCTv2.NAME,
+				State.BOB_WAITING_FOR_AT_CONFIRM.name(), State.BOB_WAITING_FOR_AT_CONFIRM.value,
+				creator.getAddress(), atAddress, timestamp, tradeBotCreateRequest.qortAmount,
+				tradeNativePublicKey, tradeNativePublicKeyHash, tradeNativeAddress,
+				null, null,
+				SupportedBlockchain.DOGECOIN.name(),
+				tradeForeignPublicKey, tradeForeignPublicKeyHash,
+				tradeBotCreateRequest.foreignAmount, null, null, null, dogecoinReceivingAccountInfo);
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, () -> String.format("Built AT %s. Waiting for deployment", atAddress));
+
+		// Attempt to backup the trade bot data
+		TradeBot.backupTradeBotData(repository, null);
+
+		// Return to user for signing and broadcast as we don't have their Qortal private key
+		try {
+			return DeployAtTransactionTransformer.toBytes(deployAtTransactionData);
+		} catch (TransformationException e) {
+			throw new DataException("Failed to transform DEPLOY_AT transaction?", e);
+		}
+	}
+
+	/**
+	 * Creates a trade-bot entry from the 'Alice' viewpoint, i.e. matching DOGE to an existing offer.
+	 * <p>
+	 * Requires a chosen trade offer from Bob, passed by <tt>crossChainTradeData</tt>
+	 * and access to a Dogecoin wallet via <tt>xprv58</tt>.
+	 * <p>
+	 * The <tt>crossChainTradeData</tt> contains the current trade offer state
+	 * as extracted from the AT's data segment.
+	 * <p>
+	 * Access to a funded wallet is via a Dogecoin BIP32 hierarchical deterministic key,
+	 * passed via <tt>xprv58</tt>.
+	 * <b>This key will be stored in your node's database</b>
+	 * to allow trade-bot to create/fund the necessary P2SH transactions!
+	 * However, due to the nature of BIP32 keys, it is possible to give the trade-bot
+	 * only a subset of wallet access (see BIP32 for more details).
+	 * <p>
+	 * As an example, the xprv58 can be extract from a <i>legacy, password-less</i>
+	 * Electrum wallet by going to the console tab and entering:<br>
+	 * <tt>wallet.keystore.xprv</tt><br>
+	 * which should result in a base58 string starting with either 'xprv' (for Dogecoin main-net)
+	 * or 'tprv' for (Dogecoin test-net).
+	 * <p>
+	 * It is envisaged that the value in <tt>xprv58</tt> will actually come from a Qortal-UI-managed wallet.
+	 * <p>
+	 * If sufficient funds are available, <b>this method will actually fund the P2SH-A</b>
+	 * with the Dogecoin amount expected by 'Bob'.
+	 * <p>
+	 * If the Dogecoin transaction is successfully broadcast to the network then
+	 * we also send a MESSAGE to Bob's trade-bot to let them know.
+	 * <p>
+	 * The trade-bot entry is saved to the repository and the cross-chain trading process commences.
+	 * <p>
+	 * @param repository
+	 * @param crossChainTradeData chosen trade OFFER that Alice wants to match
+	 * @param xprv58 funded wallet xprv in base58
+	 * @return true if P2SH-A funding transaction successfully broadcast to Dogecoin network, false otherwise
+	 * @throws DataException
+	 */
+	public ResponseResult startResponse(Repository repository, ATData atData, ACCT acct, CrossChainTradeData crossChainTradeData, String xprv58, String receivingAddress) throws DataException {
+		byte[] tradePrivateKey = TradeBot.generateTradePrivateKey();
+		byte[] secretA = TradeBot.generateSecret();
+		byte[] hashOfSecretA = Crypto.hash160(secretA);
+
+		byte[] tradeNativePublicKey = TradeBot.deriveTradeNativePublicKey(tradePrivateKey);
+		byte[] tradeNativePublicKeyHash = Crypto.hash160(tradeNativePublicKey);
+		String tradeNativeAddress = Crypto.toAddress(tradeNativePublicKey);
+
+		byte[] tradeForeignPublicKey = TradeBot.deriveTradeForeignPublicKey(tradePrivateKey);
+		byte[] tradeForeignPublicKeyHash = Crypto.hash160(tradeForeignPublicKey);
+		byte[] receivingPublicKeyHash = Base58.decode(receivingAddress); // Actually the whole address, not just PKH
+
+		// We need to generate lockTime-A: add tradeTimeout to now
+		long now = NTP.getTime();
+		int lockTimeA = crossChainTradeData.tradeTimeout * 60 + (int) (now / 1000L);
+
+		TradeBotData tradeBotData =  new TradeBotData(tradePrivateKey, DogecoinACCTv2.NAME,
+				State.ALICE_WAITING_FOR_AT_LOCK.name(), State.ALICE_WAITING_FOR_AT_LOCK.value,
+				receivingAddress, crossChainTradeData.qortalAtAddress, now, crossChainTradeData.qortAmount,
+				tradeNativePublicKey, tradeNativePublicKeyHash, tradeNativeAddress,
+				secretA, hashOfSecretA,
+				SupportedBlockchain.DOGECOIN.name(),
+				tradeForeignPublicKey, tradeForeignPublicKeyHash,
+				crossChainTradeData.expectedForeignAmount, xprv58, null, lockTimeA, receivingPublicKeyHash);
+
+		// Attempt to backup the trade bot data
+		// Include tradeBotData as an additional parameter, since it's not in the repository yet
+		TradeBot.backupTradeBotData(repository, Arrays.asList(tradeBotData));
+
+		// Check we have enough funds via xprv58 to fund P2SH to cover expectedForeignAmount
+		long p2shFee;
+		try {
+			p2shFee = Dogecoin.getInstance().getP2shFee(now);
+		} catch (ForeignBlockchainException e) {
+			LOGGER.debug("Couldn't estimate Dogecoin fees?");
+			return ResponseResult.NETWORK_ISSUE;
+		}
+
+		// Fee for redeem/refund is subtracted from P2SH-A balance.
+		// Do not include fee for funding transaction as this is covered by buildSpend()
+		long amountA = crossChainTradeData.expectedForeignAmount + p2shFee /*redeeming/refunding P2SH-A*/;
+
+		// P2SH-A to be funded
+		byte[] redeemScriptBytes = BitcoinyHTLC.buildScript(tradeForeignPublicKeyHash, lockTimeA, crossChainTradeData.creatorForeignPKH, hashOfSecretA);
+		String p2shAddress = Dogecoin.getInstance().deriveP2shAddress(redeemScriptBytes);
+
+		// Build transaction for funding P2SH-A
+		Transaction p2shFundingTransaction = Dogecoin.getInstance().buildSpend(tradeBotData.getForeignKey(), p2shAddress, amountA);
+		if (p2shFundingTransaction == null) {
+			LOGGER.debug("Unable to build P2SH-A funding transaction - lack of funds?");
+			return ResponseResult.BALANCE_ISSUE;
+		}
+
+		try {
+			Dogecoin.getInstance().broadcastTransaction(p2shFundingTransaction);
+		} catch (ForeignBlockchainException e) {
+			// We couldn't fund P2SH-A at this time
+			LOGGER.debug("Couldn't broadcast P2SH-A funding transaction?");
+			return ResponseResult.NETWORK_ISSUE;
+		}
+
+		// Attempt to send MESSAGE to Bob's Qortal trade address
+		byte[] messageData = DogecoinACCTv2.buildOfferMessage(tradeBotData.getTradeForeignPublicKeyHash(), tradeBotData.getHashOfSecret(), tradeBotData.getLockTimeA());
+		String messageRecipient = crossChainTradeData.qortalCreatorTradeAddress;
+
+		boolean isMessageAlreadySent = repository.getMessageRepository().exists(tradeBotData.getTradeNativePublicKey(), messageRecipient, messageData);
+		if (!isMessageAlreadySent) {
+			PrivateKeyAccount sender = new PrivateKeyAccount(repository, tradeBotData.getTradePrivateKey());
+			MessageTransaction messageTransaction = MessageTransaction.build(repository, sender, Group.NO_GROUP, messageRecipient, messageData, false, false);
+
+			messageTransaction.computeNonce();
+			messageTransaction.sign(sender);
+
+			// reset repository state to prevent deadlock
+			repository.discardChanges();
+			ValidationResult result = messageTransaction.importAsUnconfirmed();
+
+			if (result != ValidationResult.OK) {
+				LOGGER.warn(() -> String.format("Unable to send MESSAGE to Bob's trade-bot %s: %s", messageRecipient, result.name()));
+				return ResponseResult.NETWORK_ISSUE;
+			}
+		}
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, () -> String.format("Funding P2SH-A %s. Messaged Bob. Waiting for AT-lock", p2shAddress));
+
+		return ResponseResult.OK;
+	}
+
+	@Override
+	public boolean canDelete(Repository repository, TradeBotData tradeBotData) throws DataException {
+		State tradeBotState = State.valueOf(tradeBotData.getStateValue());
+		if (tradeBotState == null)
+			return true;
+
+		// If the AT doesn't exist then we might as well let the user tidy up
+		if (!repository.getATRepository().exists(tradeBotData.getAtAddress()))
+			return true;
+
+		switch (tradeBotState) {
+			case BOB_WAITING_FOR_AT_CONFIRM:
+			case ALICE_DONE:
+			case BOB_DONE:
+			case ALICE_REFUNDED:
+			case BOB_REFUNDED:
+				return true;
+
+			default:
+				return false;
+		}
+	}
+
+	@Override
+	public void progress(Repository repository, TradeBotData tradeBotData) throws DataException, ForeignBlockchainException {
+		State tradeBotState = State.valueOf(tradeBotData.getStateValue());
+		if (tradeBotState == null) {
+			LOGGER.info(() -> String.format("Trade-bot entry for AT %s has invalid state?", tradeBotData.getAtAddress()));
+			return;
+		}
+
+		ATData atData = null;
+		CrossChainTradeData tradeData = null;
+
+		if (tradeBotState.requiresAtData) {
+			// Attempt to fetch AT data
+			atData = repository.getATRepository().fromATAddress(tradeBotData.getAtAddress());
+			if (atData == null) {
+				LOGGER.debug(() -> String.format("Unable to fetch trade AT %s from repository", tradeBotData.getAtAddress()));
+				return;
+			}
+
+			if (tradeBotState.requiresTradeData) {
+				tradeData = DogecoinACCTv2.getInstance().populateTradeData(repository, atData);
+				if (tradeData == null) {
+					LOGGER.warn(() -> String.format("Unable to fetch ACCT trade data for AT %s from repository", tradeBotData.getAtAddress()));
+					return;
+				}
+			}
+		}
+
+		switch (tradeBotState) {
+			case BOB_WAITING_FOR_AT_CONFIRM:
+				handleBobWaitingForAtConfirm(repository, tradeBotData);
+				break;
+
+			case BOB_WAITING_FOR_MESSAGE:
+				TradeBot.getInstance().updatePresence(repository, tradeBotData, tradeData);
+				handleBobWaitingForMessage(repository, tradeBotData, atData, tradeData);
+				break;
+
+			case ALICE_WAITING_FOR_AT_LOCK:
+				TradeBot.getInstance().updatePresence(repository, tradeBotData, tradeData);
+				handleAliceWaitingForAtLock(repository, tradeBotData, atData, tradeData);
+				break;
+
+			case BOB_WAITING_FOR_AT_REDEEM:
+				TradeBot.getInstance().updatePresence(repository, tradeBotData, tradeData);
+				handleBobWaitingForAtRedeem(repository, tradeBotData, atData, tradeData);
+				break;
+
+			case ALICE_DONE:
+			case BOB_DONE:
+				break;
+
+			case ALICE_REFUNDING_A:
+				TradeBot.getInstance().updatePresence(repository, tradeBotData, tradeData);
+				handleAliceRefundingP2shA(repository, tradeBotData, atData, tradeData);
+				break;
+
+			case ALICE_REFUNDED:
+			case BOB_REFUNDED:
+				break;
+		}
+	}
+
+	/**
+	 * Trade-bot is waiting for Bob's AT to deploy.
+	 * <p>
+	 * If AT is deployed, then trade-bot's next step is to wait for MESSAGE from Alice.
+	 */
+	private void handleBobWaitingForAtConfirm(Repository repository, TradeBotData tradeBotData) throws DataException {
+		if (!repository.getATRepository().exists(tradeBotData.getAtAddress())) {
+			if (NTP.getTime() - tradeBotData.getTimestamp() <= MAX_AT_CONFIRMATION_PERIOD)
+				return;
+
+			// We've waited ages for AT to be confirmed into a block but something has gone awry.
+			// After this long we assume transaction loss so give up with trade-bot entry too.
+			tradeBotData.setState(State.BOB_REFUNDED.name());
+			tradeBotData.setStateValue(State.BOB_REFUNDED.value);
+			tradeBotData.setTimestamp(NTP.getTime());
+			// We delete trade-bot entry here instead of saving, hence not using updateTradeBotState()
+			repository.getCrossChainRepository().delete(tradeBotData.getTradePrivateKey());
+			repository.saveChanges();
+
+			LOGGER.info(() -> String.format("AT %s never confirmed. Giving up on trade", tradeBotData.getAtAddress()));
+			TradeBot.notifyStateChange(tradeBotData);
+			return;
+		}
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_WAITING_FOR_MESSAGE,
+				() -> String.format("AT %s confirmed ready. Waiting for trade message", tradeBotData.getAtAddress()));
+	}
+
+	/**
+	 * Trade-bot is waiting for MESSAGE from Alice's trade-bot, containing Alice's trade info.
+	 * <p>
+	 * It's possible Bob has cancelling his trade offer, receiving an automatic QORT refund,
+	 * in which case trade-bot is done with this specific trade and finalizes on refunded state.
+	 * <p>
+	 * Assuming trade is still on offer, trade-bot checks the contents of MESSAGE from Alice's trade-bot.
+	 * <p>
+	 * Details from Alice are used to derive P2SH-A address and this is checked for funding balance.
+	 * <p>
+	 * Assuming P2SH-A has at least expected Dogecoin balance,
+	 * Bob's trade-bot constructs a zero-fee, PoW MESSAGE to send to Bob's AT with more trade details.
+	 * <p>
+	 * On processing this MESSAGE, Bob's AT should switch into 'TRADE' mode and only trade with Alice.
+	 * <p>
+	 * Trade-bot's next step is to wait for Alice to redeem the AT, which will allow Bob to
+	 * extract secret-A needed to redeem Alice's P2SH.
+	 * @throws ForeignBlockchainException
+	 */
+	private void handleBobWaitingForMessage(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		// If AT has finished then Bob likely cancelled his trade offer
+		if (atData.getIsFinished()) {
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_REFUNDED,
+					() -> String.format("AT %s cancelled - trading aborted", tradeBotData.getAtAddress()));
+			return;
+		}
+
+		Dogecoin dogecoin = Dogecoin.getInstance();
+
+		String address = tradeBotData.getTradeNativeAddress();
+		List<MessageTransactionData> messageTransactionsData = repository.getMessageRepository().getMessagesByParticipants(null, address, null, null, null);
+
+		for (MessageTransactionData messageTransactionData : messageTransactionsData) {
+			if (messageTransactionData.isText())
+				continue;
+
+			// We're expecting: HASH160(secret-A), Alice's Dogecoin pubkeyhash and lockTime-A
+			byte[] messageData = messageTransactionData.getData();
+			DogecoinACCTv2.OfferMessageData offerMessageData = DogecoinACCTv2.extractOfferMessageData(messageData);
+			if (offerMessageData == null)
+				continue;
+
+			byte[] aliceForeignPublicKeyHash = offerMessageData.partnerDogecoinPKH;
+			byte[] hashOfSecretA = offerMessageData.hashOfSecretA;
+			int lockTimeA = (int) offerMessageData.lockTimeA;
+			long messageTimestamp = messageTransactionData.getTimestamp();
+			int refundTimeout = DogecoinACCTv2.calcRefundTimeout(messageTimestamp, lockTimeA);
+
+			// Determine P2SH-A address and confirm funded
+			byte[] redeemScriptA = BitcoinyHTLC.buildScript(aliceForeignPublicKeyHash, lockTimeA, tradeBotData.getTradeForeignPublicKeyHash(), hashOfSecretA);
+			String p2shAddressA = dogecoin.deriveP2shAddress(redeemScriptA);
+
+			long feeTimestamp = calcFeeTimestamp(lockTimeA, crossChainTradeData.tradeTimeout);
+			long p2shFee = Dogecoin.getInstance().getP2shFee(feeTimestamp);
+			final long minimumAmountA = tradeBotData.getForeignAmount() + p2shFee;
+
+			BitcoinyHTLC.Status htlcStatusA = BitcoinyHTLC.determineHtlcStatus(dogecoin.getBlockchainProvider(), p2shAddressA, minimumAmountA);
+
+			switch (htlcStatusA) {
+				case UNFUNDED:
+				case FUNDING_IN_PROGRESS:
+					// There might be another MESSAGE from someone else with an actually funded P2SH-A...
+					continue;
+
+				case REDEEM_IN_PROGRESS:
+				case REDEEMED:
+					// We've already redeemed this?
+					TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_DONE,
+							() -> String.format("P2SH-A %s already spent? Assuming trade complete", p2shAddressA));
+					return;
+
+				case REFUND_IN_PROGRESS:
+				case REFUNDED:
+					// This P2SH-A is burnt, but there might be another MESSAGE from someone else with an actually funded P2SH-A...
+					continue;
+
+				case FUNDED:
+					// Fall-through out of switch...
+					break;
+			}
+
+			// Good to go - send MESSAGE to AT
+
+			String aliceNativeAddress = Crypto.toAddress(messageTransactionData.getCreatorPublicKey());
+
+			// Build outgoing message, padding each part to 32 bytes to make it easier for AT to consume
+			byte[] outgoingMessageData = DogecoinACCTv2.buildTradeMessage(aliceNativeAddress, aliceForeignPublicKeyHash, hashOfSecretA, lockTimeA, refundTimeout);
+			String messageRecipient = tradeBotData.getAtAddress();
+
+			boolean isMessageAlreadySent = repository.getMessageRepository().exists(tradeBotData.getTradeNativePublicKey(), messageRecipient, outgoingMessageData);
+			if (!isMessageAlreadySent) {
+				PrivateKeyAccount sender = new PrivateKeyAccount(repository, tradeBotData.getTradePrivateKey());
+				MessageTransaction outgoingMessageTransaction = MessageTransaction.build(repository, sender, Group.NO_GROUP, messageRecipient, outgoingMessageData, false, false);
+
+				outgoingMessageTransaction.computeNonce();
+				outgoingMessageTransaction.sign(sender);
+
+				// reset repository state to prevent deadlock
+				repository.discardChanges();
+				ValidationResult result = outgoingMessageTransaction.importAsUnconfirmed();
+
+				if (result != ValidationResult.OK) {
+					LOGGER.warn(() -> String.format("Unable to send MESSAGE to AT %s: %s", messageRecipient, result.name()));
+					return;
+				}
+			}
+
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_WAITING_FOR_AT_REDEEM,
+					() -> String.format("Locked AT %s to %s. Waiting for AT redeem", tradeBotData.getAtAddress(), aliceNativeAddress));
+
+			return;
+		}
+	}
+
+	/**
+	 * Trade-bot is waiting for Bob's AT to switch to TRADE mode and lock trade to Alice only.
+	 * <p>
+	 * It's possible that Bob has cancelled his trade offer in the mean time, or that somehow
+	 * this process has taken so long that we've reached P2SH-A's locktime, or that someone else
+	 * has managed to trade with Bob. In any of these cases, trade-bot switches to begin the refunding process.
+	 * <p>
+	 * Assuming Bob's AT is locked to Alice, trade-bot checks AT's state data to make sure it is correct.
+	 * <p>
+	 * If all is well, trade-bot then redeems AT using Alice's secret-A, releasing Bob's QORT to Alice.
+	 * <p>
+	 * In revealing a valid secret-A, Bob can then redeem the DOGE funds from P2SH-A.
+	 * <p>
+	 * @throws ForeignBlockchainException
+	 */
+	private void handleAliceWaitingForAtLock(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		if (aliceUnexpectedState(repository, tradeBotData, atData, crossChainTradeData))
+			return;
+
+		Dogecoin dogecoin = Dogecoin.getInstance();
+		int lockTimeA = tradeBotData.getLockTimeA();
+
+		// Refund P2SH-A if we've passed lockTime-A
+		if (NTP.getTime() >= lockTimeA * 1000L) {
+			byte[] redeemScriptA = BitcoinyHTLC.buildScript(tradeBotData.getTradeForeignPublicKeyHash(), lockTimeA, crossChainTradeData.creatorForeignPKH, tradeBotData.getHashOfSecret());
+			String p2shAddressA = dogecoin.deriveP2shAddress(redeemScriptA);
+
+			long feeTimestamp = calcFeeTimestamp(lockTimeA, crossChainTradeData.tradeTimeout);
+			long p2shFee = Dogecoin.getInstance().getP2shFee(feeTimestamp);
+			long minimumAmountA = crossChainTradeData.expectedForeignAmount + p2shFee;
+
+			BitcoinyHTLC.Status htlcStatusA = BitcoinyHTLC.determineHtlcStatus(dogecoin.getBlockchainProvider(), p2shAddressA, minimumAmountA);
+
+			switch (htlcStatusA) {
+				case UNFUNDED:
+				case FUNDING_IN_PROGRESS:
+				case FUNDED:
+					break;
+
+				case REDEEM_IN_PROGRESS:
+				case REDEEMED:
+					// Already redeemed?
+					TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_DONE,
+							() -> String.format("P2SH-A %s already spent? Assuming trade completed", p2shAddressA));
+					return;
+
+				case REFUND_IN_PROGRESS:
+				case REFUNDED:
+					TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDED,
+							() -> String.format("P2SH-A %s already refunded. Trade aborted", p2shAddressA));
+					return;
+
+			}
+
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDING_A,
+					() -> atData.getIsFinished()
+					? String.format("AT %s cancelled. Refunding P2SH-A %s - aborting trade", tradeBotData.getAtAddress(), p2shAddressA)
+					: String.format("LockTime-A reached, refunding P2SH-A %s - aborting trade", p2shAddressA));
+
+			return;
+		}
+
+		// We're waiting for AT to be in TRADE mode
+		if (crossChainTradeData.mode != AcctMode.TRADING)
+			return;
+
+		// AT is in TRADE mode and locked to us as checked by aliceUnexpectedState() above
+
+		// Find our MESSAGE to AT from previous state
+		List<MessageTransactionData> messageTransactionsData = repository.getMessageRepository().getMessagesByParticipants(tradeBotData.getTradeNativePublicKey(),
+				crossChainTradeData.qortalCreatorTradeAddress, null, null, null);
+		if (messageTransactionsData == null || messageTransactionsData.isEmpty()) {
+			LOGGER.warn(() -> String.format("Unable to find our message to trade creator %s?", crossChainTradeData.qortalCreatorTradeAddress));
+			return;
+		}
+
+		long recipientMessageTimestamp = messageTransactionsData.get(0).getTimestamp();
+		int refundTimeout = DogecoinACCTv2.calcRefundTimeout(recipientMessageTimestamp, lockTimeA);
+
+		// Our calculated refundTimeout should match AT's refundTimeout
+		if (refundTimeout != crossChainTradeData.refundTimeout) {
+			LOGGER.debug(() -> String.format("Trade AT refundTimeout '%d' doesn't match our refundTimeout '%d'", crossChainTradeData.refundTimeout, refundTimeout));
+			// We'll eventually refund
+			return;
+		}
+
+		// We're good to redeem AT
+
+		// Send 'redeem' MESSAGE to AT using both secret
+		byte[] secretA = tradeBotData.getSecret();
+		String qortalReceivingAddress = Base58.encode(tradeBotData.getReceivingAccountInfo()); // Actually contains whole address, not just PKH
+		byte[] messageData = DogecoinACCTv2.buildRedeemMessage(secretA, qortalReceivingAddress);
+		String messageRecipient = tradeBotData.getAtAddress();
+
+		boolean isMessageAlreadySent = repository.getMessageRepository().exists(tradeBotData.getTradeNativePublicKey(), messageRecipient, messageData);
+		if (!isMessageAlreadySent) {
+			PrivateKeyAccount sender = new PrivateKeyAccount(repository, tradeBotData.getTradePrivateKey());
+			MessageTransaction messageTransaction = MessageTransaction.build(repository, sender, Group.NO_GROUP, messageRecipient, messageData, false, false);
+
+			messageTransaction.computeNonce();
+			messageTransaction.sign(sender);
+
+			// Reset repository state to prevent deadlock
+			repository.discardChanges();
+			ValidationResult result = messageTransaction.importAsUnconfirmed();
+
+			if (result != ValidationResult.OK) {
+				LOGGER.warn(() -> String.format("Unable to send MESSAGE to AT %s: %s", messageRecipient, result.name()));
+				return;
+			}
+		}
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_DONE,
+				() -> String.format("Redeeming AT %s. Funds should arrive at %s",
+						tradeBotData.getAtAddress(), qortalReceivingAddress));
+	}
+
+	/**
+	 * Trade-bot is waiting for Alice to redeem Bob's AT, thus revealing secret-A which is required to spend the DOGE funds from P2SH-A.
+	 * <p>
+	 * It's possible that Bob's AT has reached its trading timeout and automatically refunded QORT back to Bob. In which case,
+	 * trade-bot is done with this specific trade and finalizes in refunded state.
+	 * <p>
+	 * Assuming trade-bot can extract a valid secret-A from Alice's MESSAGE then trade-bot uses that to redeem the DOGE funds from P2SH-A
+	 * to Bob's 'foreign'/Dogecoin trade legacy-format address, as derived from trade private key.
+	 * <p>
+	 * (This could potentially be 'improved' to send DOGE to any address of Bob's choosing by changing the transaction output).
+	 * <p>
+	 * If trade-bot successfully broadcasts the transaction, then this specific trade is done.
+	 * @throws ForeignBlockchainException
+	 */
+	private void handleBobWaitingForAtRedeem(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		// AT should be 'finished' once Alice has redeemed QORT funds
+		if (!atData.getIsFinished())
+			// Not finished yet
+			return;
+
+		// If AT is REFUNDED or CANCELLED then something has gone wrong
+		if (crossChainTradeData.mode == AcctMode.REFUNDED || crossChainTradeData.mode == AcctMode.CANCELLED) {
+			// Alice hasn't redeemed the QORT, so there is no point in trying to redeem the DOGE
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_REFUNDED,
+					() -> String.format("AT %s has auto-refunded - trade aborted", tradeBotData.getAtAddress()));
+
+			return;
+		}
+
+		byte[] secretA = DogecoinACCTv2.getInstance().findSecretA(repository, crossChainTradeData);
+		if (secretA == null) {
+			LOGGER.debug(() -> String.format("Unable to find secret-A from redeem message to AT %s?", tradeBotData.getAtAddress()));
+			return;
+		}
+
+		// Use secret-A to redeem P2SH-A
+
+		Dogecoin dogecoin = Dogecoin.getInstance();
+
+		byte[] receivingAccountInfo = tradeBotData.getReceivingAccountInfo();
+		int lockTimeA = crossChainTradeData.lockTimeA;
+		byte[] redeemScriptA = BitcoinyHTLC.buildScript(crossChainTradeData.partnerForeignPKH, lockTimeA, crossChainTradeData.creatorForeignPKH, crossChainTradeData.hashOfSecretA);
+		String p2shAddressA = dogecoin.deriveP2shAddress(redeemScriptA);
+
+		// Fee for redeem/refund is subtracted from P2SH-A balance.
+		long feeTimestamp = calcFeeTimestamp(lockTimeA, crossChainTradeData.tradeTimeout);
+		long p2shFee = Dogecoin.getInstance().getP2shFee(feeTimestamp);
+		long minimumAmountA = crossChainTradeData.expectedForeignAmount + p2shFee;
+		BitcoinyHTLC.Status htlcStatusA = BitcoinyHTLC.determineHtlcStatus(dogecoin.getBlockchainProvider(), p2shAddressA, minimumAmountA);
+
+		switch (htlcStatusA) {
+			case UNFUNDED:
+			case FUNDING_IN_PROGRESS:
+				// P2SH-A suddenly not funded? Our best bet at this point is to hope for AT auto-refund
+				return;
+
+			case REDEEM_IN_PROGRESS:
+			case REDEEMED:
+				// Double-check that we have redeemed P2SH-A...
+				break;
+
+			case REFUND_IN_PROGRESS:
+			case REFUNDED:
+				// Wait for AT to auto-refund
+				return;
+
+			case FUNDED: {
+				Coin redeemAmount = Coin.valueOf(crossChainTradeData.expectedForeignAmount);
+				ECKey redeemKey = ECKey.fromPrivate(tradeBotData.getTradePrivateKey());
+				List<TransactionOutput> fundingOutputs = dogecoin.getUnspentOutputs(p2shAddressA);
+
+				Transaction p2shRedeemTransaction = BitcoinyHTLC.buildRedeemTransaction(dogecoin.getNetworkParameters(), redeemAmount, redeemKey,
+						fundingOutputs, redeemScriptA, secretA, receivingAccountInfo);
+
+				dogecoin.broadcastTransaction(p2shRedeemTransaction);
+				break;
+			}
+		}
+
+		String receivingAddress = dogecoin.pkhToAddress(receivingAccountInfo);
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_DONE,
+				() -> String.format("P2SH-A %s redeemed. Funds should arrive at %s", tradeBotData.getAtAddress(), receivingAddress));
+	}
+
+	/**
+	 * Trade-bot is attempting to refund P2SH-A.
+	 * @throws ForeignBlockchainException
+	 */
+	private void handleAliceRefundingP2shA(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		int lockTimeA = tradeBotData.getLockTimeA();
+
+		// We can't refund P2SH-A until lockTime-A has passed
+		if (NTP.getTime() <= lockTimeA * 1000L)
+			return;
+
+		Dogecoin dogecoin = Dogecoin.getInstance();
+
+		// We can't refund P2SH-A until median block time has passed lockTime-A (see BIP113)
+		int medianBlockTime = dogecoin.getMedianBlockTime();
+		if (medianBlockTime <= lockTimeA)
+			return;
+
+		byte[] redeemScriptA = BitcoinyHTLC.buildScript(tradeBotData.getTradeForeignPublicKeyHash(), lockTimeA, crossChainTradeData.creatorForeignPKH, tradeBotData.getHashOfSecret());
+		String p2shAddressA = dogecoin.deriveP2shAddress(redeemScriptA);
+
+		// Fee for redeem/refund is subtracted from P2SH-A balance.
+		long feeTimestamp = calcFeeTimestamp(lockTimeA, crossChainTradeData.tradeTimeout);
+		long p2shFee = Dogecoin.getInstance().getP2shFee(feeTimestamp);
+		long minimumAmountA = crossChainTradeData.expectedForeignAmount + p2shFee;
+		BitcoinyHTLC.Status htlcStatusA = BitcoinyHTLC.determineHtlcStatus(dogecoin.getBlockchainProvider(), p2shAddressA, minimumAmountA);
+
+		switch (htlcStatusA) {
+			case UNFUNDED:
+			case FUNDING_IN_PROGRESS:
+				// Still waiting for P2SH-A to be funded...
+				return;
+
+			case REDEEM_IN_PROGRESS:
+			case REDEEMED:
+				// Too late!
+				TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_DONE,
+						() -> String.format("P2SH-A %s already spent!", p2shAddressA));
+				return;
+
+			case REFUND_IN_PROGRESS:
+			case REFUNDED:
+				break;
+
+			case FUNDED:{
+				Coin refundAmount = Coin.valueOf(crossChainTradeData.expectedForeignAmount);
+				ECKey refundKey = ECKey.fromPrivate(tradeBotData.getTradePrivateKey());
+				List<TransactionOutput> fundingOutputs = dogecoin.getUnspentOutputs(p2shAddressA);
+
+				// Determine receive address for refund
+				String receiveAddress = dogecoin.getUnusedReceiveAddress(tradeBotData.getForeignKey());
+				Address receiving = Address.fromString(dogecoin.getNetworkParameters(), receiveAddress);
+
+				Transaction p2shRefundTransaction = BitcoinyHTLC.buildRefundTransaction(dogecoin.getNetworkParameters(), refundAmount, refundKey,
+						fundingOutputs, redeemScriptA, lockTimeA, receiving.getHash());
+
+				dogecoin.broadcastTransaction(p2shRefundTransaction);
+				break;
+			}
+		}
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDED,
+				() -> String.format("LockTime-A reached. Refunded P2SH-A %s. Trade aborted", p2shAddressA));
+	}
+
+	/**
+	 * Returns true if Alice finds AT unexpectedly cancelled, refunded, redeemed or locked to someone else.
+	 * <p>
+	 * Will automatically update trade-bot state to <tt>ALICE_REFUNDING_A</tt> or <tt>ALICE_DONE</tt> as necessary.
+	 * 
+	 * @throws DataException
+	 * @throws ForeignBlockchainException
+	 */
+	private boolean aliceUnexpectedState(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		// This is OK
+		if (!atData.getIsFinished() && crossChainTradeData.mode == AcctMode.OFFERING)
+			return false;
+
+		boolean isAtLockedToUs = tradeBotData.getTradeNativeAddress().equals(crossChainTradeData.qortalPartnerAddress);
+
+		if (!atData.getIsFinished() && crossChainTradeData.mode == AcctMode.TRADING)
+			if (isAtLockedToUs) {
+				// AT is trading with us - OK
+				return false;
+			} else {
+				TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDING_A,
+						() -> String.format("AT %s trading with someone else: %s. Refunding & aborting trade", tradeBotData.getAtAddress(), crossChainTradeData.qortalPartnerAddress));
+
+				return true;
+			}
+
+		if (atData.getIsFinished() && crossChainTradeData.mode == AcctMode.REDEEMED && isAtLockedToUs) {
+			// We've redeemed already?
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_DONE,
+					() -> String.format("AT %s already redeemed by us. Trade completed", tradeBotData.getAtAddress()));
+		} else {
+			// Any other state is not good, so start defensive refund
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDING_A,
+					() -> String.format("AT %s cancelled/refunded/redeemed by someone else/invalid state. Refunding & aborting trade", tradeBotData.getAtAddress()));
+		}
+
+		return true;
+	}
+
+	private long calcFeeTimestamp(int lockTimeA, int tradeTimeout) {
+		return (lockTimeA - tradeTimeout * 60) * 1000L;
+	}
+
+}

src/main/java/org/qortal/controller/tradebot/DogecoinACCTv3TradeBot.java

@@ -0,0 +1,885 @@
+package org.qortal.controller.tradebot;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.bitcoinj.core.*;
+import org.bitcoinj.script.Script.ScriptType;
+import org.qortal.account.PrivateKeyAccount;
+import org.qortal.account.PublicKeyAccount;
+import org.qortal.api.model.crosschain.TradeBotCreateRequest;
+import org.qortal.asset.Asset;
+import org.qortal.crosschain.*;
+import org.qortal.crypto.Crypto;
+import org.qortal.data.at.ATData;
+import org.qortal.data.crosschain.CrossChainTradeData;
+import org.qortal.data.crosschain.TradeBotData;
+import org.qortal.data.transaction.BaseTransactionData;
+import org.qortal.data.transaction.DeployAtTransactionData;
+import org.qortal.data.transaction.MessageTransactionData;
+import org.qortal.group.Group;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.transaction.DeployAtTransaction;
+import org.qortal.transaction.MessageTransaction;
+import org.qortal.transaction.Transaction.ValidationResult;
+import org.qortal.transform.TransformationException;
+import org.qortal.transform.transaction.DeployAtTransactionTransformer;
+import org.qortal.utils.Base58;
+import org.qortal.utils.NTP;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import static java.util.Arrays.stream;
+import static java.util.stream.Collectors.toMap;
+
+/**
+ * Performing cross-chain trading steps on behalf of user.
+ * <p>
+ * We deal with three different independent state-spaces here:
+ * <ul>
+ * 	<li>Qortal blockchain</li>
+ * 	<li>Foreign blockchain</li>
+ * 	<li>Trade-bot entries</li>
+ * </ul>
+ */
+public class DogecoinACCTv3TradeBot implements AcctTradeBot {
+
+	private static final Logger LOGGER = LogManager.getLogger(DogecoinACCTv3TradeBot.class);
+
+	public enum State implements TradeBot.StateNameAndValueSupplier {
+		BOB_WAITING_FOR_AT_CONFIRM(10, false, false),
+		BOB_WAITING_FOR_MESSAGE(15, true, true),
+		BOB_WAITING_FOR_AT_REDEEM(25, true, true),
+		BOB_DONE(30, false, false),
+		BOB_REFUNDED(35, false, false),
+
+		ALICE_WAITING_FOR_AT_LOCK(85, true, true),
+		ALICE_DONE(95, false, false),
+		ALICE_REFUNDING_A(105, true, true),
+		ALICE_REFUNDED(110, false, false);
+
+		private static final Map<Integer, State> map = stream(State.values()).collect(toMap(state -> state.value, state -> state));
+
+		public final int value;
+		public final boolean requiresAtData;
+		public final boolean requiresTradeData;
+
+		State(int value, boolean requiresAtData, boolean requiresTradeData) {
+			this.value = value;
+			this.requiresAtData = requiresAtData;
+			this.requiresTradeData = requiresTradeData;
+		}
+
+		public static State valueOf(int value) {
+			return map.get(value);
+		}
+
+		@Override
+		public String getState() {
+			return this.name();
+		}
+
+		@Override
+		public int getStateValue() {
+			return this.value;
+		}
+	}
+
+	/** Maximum time Bob waits for his AT creation transaction to be confirmed into a block. (milliseconds) */
+	private static final long MAX_AT_CONFIRMATION_PERIOD = 24 * 60 * 60 * 1000L; // ms
+
+	private static DogecoinACCTv3TradeBot instance;
+
+	private final List<String> endStates = Arrays.asList(State.BOB_DONE, State.BOB_REFUNDED, State.ALICE_DONE, State.ALICE_REFUNDING_A, State.ALICE_REFUNDED).stream()
+			.map(State::name)
+			.collect(Collectors.toUnmodifiableList());
+
+	private DogecoinACCTv3TradeBot() {
+	}
+
+	public static synchronized DogecoinACCTv3TradeBot getInstance() {
+		if (instance == null)
+			instance = new DogecoinACCTv3TradeBot();
+
+		return instance;
+	}
+
+	@Override
+	public List<String> getEndStates() {
+		return this.endStates;
+	}
+
+	/**
+	 * Creates a new trade-bot entry from the "Bob" viewpoint, i.e. OFFERing QORT in exchange for DOGE.
+	 * <p>
+	 * Generates:
+	 * <ul>
+	 * 	<li>new 'trade' private key</li>
+	 * </ul>
+	 * Derives:
+	 * <ul>
+	 * 	<li>'native' (as in Qortal) public key, public key hash, address (starting with Q)</li>
+	 * 	<li>'foreign' (as in Dogecoin) public key, public key hash</li>
+	 * </ul>
+	 * A Qortal AT is then constructed including the following as constants in the 'data segment':
+	 * <ul>
+	 * 	<li>'native'/Qortal 'trade' address - used as a MESSAGE contact</li>
+	 * 	<li>'foreign'/Dogecoin public key hash - used by Alice's P2SH scripts to allow redeem</li>
+	 * 	<li>QORT amount on offer by Bob</li>
+	 * 	<li>DOGE amount expected in return by Bob (from Alice)</li>
+	 * 	<li>trading timeout, in case things go wrong and everyone needs to refund</li>
+	 * </ul>
+	 * Returns a DEPLOY_AT transaction that needs to be signed and broadcast to the Qortal network.
+	 * <p>
+	 * Trade-bot will wait for Bob's AT to be deployed before taking next step.
+	 * <p>
+	 * @param repository
+	 * @param tradeBotCreateRequest
+	 * @return raw, unsigned DEPLOY_AT transaction
+	 * @throws DataException
+	 */
+	public byte[] createTrade(Repository repository, TradeBotCreateRequest tradeBotCreateRequest) throws DataException {
+		byte[] tradePrivateKey = TradeBot.generateTradePrivateKey();
+
+		byte[] tradeNativePublicKey = TradeBot.deriveTradeNativePublicKey(tradePrivateKey);
+		byte[] tradeNativePublicKeyHash = Crypto.hash160(tradeNativePublicKey);
+		String tradeNativeAddress = Crypto.toAddress(tradeNativePublicKey);
+
+		byte[] tradeForeignPublicKey = TradeBot.deriveTradeForeignPublicKey(tradePrivateKey);
+		byte[] tradeForeignPublicKeyHash = Crypto.hash160(tradeForeignPublicKey);
+
+		// Convert Dogecoin receiving address into public key hash (we only support P2PKH at this time)
+		Address dogecoinReceivingAddress;
+		try {
+			dogecoinReceivingAddress = Address.fromString(Dogecoin.getInstance().getNetworkParameters(), tradeBotCreateRequest.receivingAddress);
+		} catch (AddressFormatException e) {
+			throw new DataException("Unsupported Dogecoin receiving address: " + tradeBotCreateRequest.receivingAddress);
+		}
+		if (dogecoinReceivingAddress.getOutputScriptType() != ScriptType.P2PKH)
+			throw new DataException("Unsupported Dogecoin receiving address: " + tradeBotCreateRequest.receivingAddress);
+
+		byte[] dogecoinReceivingAccountInfo = dogecoinReceivingAddress.getHash();
+
+		PublicKeyAccount creator = new PublicKeyAccount(repository, tradeBotCreateRequest.creatorPublicKey);
+
+		// Deploy AT
+		long timestamp = NTP.getTime();
+		byte[] reference = creator.getLastReference();
+		long fee = 0L;
+		byte[] signature = null;
+		BaseTransactionData baseTransactionData = new BaseTransactionData(timestamp, Group.NO_GROUP, reference, creator.getPublicKey(), fee, signature);
+
+		String name = "QORT/DOGE ACCT";
+		String description = "QORT/DOGE cross-chain trade";
+		String aTType = "ACCT";
+		String tags = "ACCT QORT DOGE";
+		byte[] creationBytes = DogecoinACCTv3.buildQortalAT(tradeNativeAddress, tradeForeignPublicKeyHash, tradeBotCreateRequest.qortAmount,
+				tradeBotCreateRequest.foreignAmount, tradeBotCreateRequest.tradeTimeout);
+		long amount = tradeBotCreateRequest.fundingQortAmount;
+
+		DeployAtTransactionData deployAtTransactionData = new DeployAtTransactionData(baseTransactionData, name, description, aTType, tags, creationBytes, amount, Asset.QORT);
+
+		DeployAtTransaction deployAtTransaction = new DeployAtTransaction(repository, deployAtTransactionData);
+		fee = deployAtTransaction.calcRecommendedFee();
+		deployAtTransactionData.setFee(fee);
+
+		DeployAtTransaction.ensureATAddress(deployAtTransactionData);
+		String atAddress = deployAtTransactionData.getAtAddress();
+
+		TradeBotData tradeBotData =  new TradeBotData(tradePrivateKey, DogecoinACCTv3.NAME,
+				State.BOB_WAITING_FOR_AT_CONFIRM.name(), State.BOB_WAITING_FOR_AT_CONFIRM.value,
+				creator.getAddress(), atAddress, timestamp, tradeBotCreateRequest.qortAmount,
+				tradeNativePublicKey, tradeNativePublicKeyHash, tradeNativeAddress,
+				null, null,
+				SupportedBlockchain.DOGECOIN.name(),
+				tradeForeignPublicKey, tradeForeignPublicKeyHash,
+				tradeBotCreateRequest.foreignAmount, null, null, null, dogecoinReceivingAccountInfo);
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, () -> String.format("Built AT %s. Waiting for deployment", atAddress));
+
+		// Attempt to backup the trade bot data
+		TradeBot.backupTradeBotData(repository, null);
+
+		// Return to user for signing and broadcast as we don't have their Qortal private key
+		try {
+			return DeployAtTransactionTransformer.toBytes(deployAtTransactionData);
+		} catch (TransformationException e) {
+			throw new DataException("Failed to transform DEPLOY_AT transaction?", e);
+		}
+	}
+
+	/**
+	 * Creates a trade-bot entry from the 'Alice' viewpoint, i.e. matching DOGE to an existing offer.
+	 * <p>
+	 * Requires a chosen trade offer from Bob, passed by <tt>crossChainTradeData</tt>
+	 * and access to a Dogecoin wallet via <tt>xprv58</tt>.
+	 * <p>
+	 * The <tt>crossChainTradeData</tt> contains the current trade offer state
+	 * as extracted from the AT's data segment.
+	 * <p>
+	 * Access to a funded wallet is via a Dogecoin BIP32 hierarchical deterministic key,
+	 * passed via <tt>xprv58</tt>.
+	 * <b>This key will be stored in your node's database</b>
+	 * to allow trade-bot to create/fund the necessary P2SH transactions!
+	 * However, due to the nature of BIP32 keys, it is possible to give the trade-bot
+	 * only a subset of wallet access (see BIP32 for more details).
+	 * <p>
+	 * As an example, the xprv58 can be extract from a <i>legacy, password-less</i>
+	 * Electrum wallet by going to the console tab and entering:<br>
+	 * <tt>wallet.keystore.xprv</tt><br>
+	 * which should result in a base58 string starting with either 'xprv' (for Dogecoin main-net)
+	 * or 'tprv' for (Dogecoin test-net).
+	 * <p>
+	 * It is envisaged that the value in <tt>xprv58</tt> will actually come from a Qortal-UI-managed wallet.
+	 * <p>
+	 * If sufficient funds are available, <b>this method will actually fund the P2SH-A</b>
+	 * with the Dogecoin amount expected by 'Bob'.
+	 * <p>
+	 * If the Dogecoin transaction is successfully broadcast to the network then
+	 * we also send a MESSAGE to Bob's trade-bot to let them know.
+	 * <p>
+	 * The trade-bot entry is saved to the repository and the cross-chain trading process commences.
+	 * <p>
+	 * @param repository
+	 * @param crossChainTradeData chosen trade OFFER that Alice wants to match
+	 * @param xprv58 funded wallet xprv in base58
+	 * @return true if P2SH-A funding transaction successfully broadcast to Dogecoin network, false otherwise
+	 * @throws DataException
+	 */
+	public ResponseResult startResponse(Repository repository, ATData atData, ACCT acct, CrossChainTradeData crossChainTradeData, String xprv58, String receivingAddress) throws DataException {
+		byte[] tradePrivateKey = TradeBot.generateTradePrivateKey();
+		byte[] secretA = TradeBot.generateSecret();
+		byte[] hashOfSecretA = Crypto.hash160(secretA);
+
+		byte[] tradeNativePublicKey = TradeBot.deriveTradeNativePublicKey(tradePrivateKey);
+		byte[] tradeNativePublicKeyHash = Crypto.hash160(tradeNativePublicKey);
+		String tradeNativeAddress = Crypto.toAddress(tradeNativePublicKey);
+
+		byte[] tradeForeignPublicKey = TradeBot.deriveTradeForeignPublicKey(tradePrivateKey);
+		byte[] tradeForeignPublicKeyHash = Crypto.hash160(tradeForeignPublicKey);
+		byte[] receivingPublicKeyHash = Base58.decode(receivingAddress); // Actually the whole address, not just PKH
+
+		// We need to generate lockTime-A: add tradeTimeout to now
+		long now = NTP.getTime();
+		int lockTimeA = crossChainTradeData.tradeTimeout * 60 + (int) (now / 1000L);
+
+		TradeBotData tradeBotData =  new TradeBotData(tradePrivateKey, DogecoinACCTv3.NAME,
+				State.ALICE_WAITING_FOR_AT_LOCK.name(), State.ALICE_WAITING_FOR_AT_LOCK.value,
+				receivingAddress, crossChainTradeData.qortalAtAddress, now, crossChainTradeData.qortAmount,
+				tradeNativePublicKey, tradeNativePublicKeyHash, tradeNativeAddress,
+				secretA, hashOfSecretA,
+				SupportedBlockchain.DOGECOIN.name(),
+				tradeForeignPublicKey, tradeForeignPublicKeyHash,
+				crossChainTradeData.expectedForeignAmount, xprv58, null, lockTimeA, receivingPublicKeyHash);
+
+		// Attempt to backup the trade bot data
+		// Include tradeBotData as an additional parameter, since it's not in the repository yet
+		TradeBot.backupTradeBotData(repository, Arrays.asList(tradeBotData));
+
+		// Check we have enough funds via xprv58 to fund P2SH to cover expectedForeignAmount
+		long p2shFee;
+		try {
+			p2shFee = Dogecoin.getInstance().getP2shFee(now);
+		} catch (ForeignBlockchainException e) {
+			LOGGER.debug("Couldn't estimate Dogecoin fees?");
+			return ResponseResult.NETWORK_ISSUE;
+		}
+
+		// Fee for redeem/refund is subtracted from P2SH-A balance.
+		// Do not include fee for funding transaction as this is covered by buildSpend()
+		long amountA = crossChainTradeData.expectedForeignAmount + p2shFee /*redeeming/refunding P2SH-A*/;
+
+		// P2SH-A to be funded
+		byte[] redeemScriptBytes = BitcoinyHTLC.buildScript(tradeForeignPublicKeyHash, lockTimeA, crossChainTradeData.creatorForeignPKH, hashOfSecretA);
+		String p2shAddress = Dogecoin.getInstance().deriveP2shAddress(redeemScriptBytes);
+
+		// Build transaction for funding P2SH-A
+		Transaction p2shFundingTransaction = Dogecoin.getInstance().buildSpend(tradeBotData.getForeignKey(), p2shAddress, amountA);
+		if (p2shFundingTransaction == null) {
+			LOGGER.debug("Unable to build P2SH-A funding transaction - lack of funds?");
+			return ResponseResult.BALANCE_ISSUE;
+		}
+
+		try {
+			Dogecoin.getInstance().broadcastTransaction(p2shFundingTransaction);
+		} catch (ForeignBlockchainException e) {
+			// We couldn't fund P2SH-A at this time
+			LOGGER.debug("Couldn't broadcast P2SH-A funding transaction?");
+			return ResponseResult.NETWORK_ISSUE;
+		}
+
+		// Attempt to send MESSAGE to Bob's Qortal trade address
+		byte[] messageData = DogecoinACCTv3.buildOfferMessage(tradeBotData.getTradeForeignPublicKeyHash(), tradeBotData.getHashOfSecret(), tradeBotData.getLockTimeA());
+		String messageRecipient = crossChainTradeData.qortalCreatorTradeAddress;
+
+		boolean isMessageAlreadySent = repository.getMessageRepository().exists(tradeBotData.getTradeNativePublicKey(), messageRecipient, messageData);
+		if (!isMessageAlreadySent) {
+			PrivateKeyAccount sender = new PrivateKeyAccount(repository, tradeBotData.getTradePrivateKey());
+			MessageTransaction messageTransaction = MessageTransaction.build(repository, sender, Group.NO_GROUP, messageRecipient, messageData, false, false);
+
+			messageTransaction.computeNonce();
+			messageTransaction.sign(sender);
+
+			// reset repository state to prevent deadlock
+			repository.discardChanges();
+			ValidationResult result = messageTransaction.importAsUnconfirmed();
+
+			if (result != ValidationResult.OK) {
+				LOGGER.warn(() -> String.format("Unable to send MESSAGE to Bob's trade-bot %s: %s", messageRecipient, result.name()));
+				return ResponseResult.NETWORK_ISSUE;
+			}
+		}
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, () -> String.format("Funding P2SH-A %s. Messaged Bob. Waiting for AT-lock", p2shAddress));
+
+		return ResponseResult.OK;
+	}
+
+	@Override
+	public boolean canDelete(Repository repository, TradeBotData tradeBotData) throws DataException {
+		State tradeBotState = State.valueOf(tradeBotData.getStateValue());
+		if (tradeBotState == null)
+			return true;
+
+		// If the AT doesn't exist then we might as well let the user tidy up
+		if (!repository.getATRepository().exists(tradeBotData.getAtAddress()))
+			return true;
+
+		switch (tradeBotState) {
+			case BOB_WAITING_FOR_AT_CONFIRM:
+			case ALICE_DONE:
+			case BOB_DONE:
+			case ALICE_REFUNDED:
+			case BOB_REFUNDED:
+			case ALICE_REFUNDING_A:
+				return true;
+
+			default:
+				return false;
+		}
+	}
+
+	@Override
+	public void progress(Repository repository, TradeBotData tradeBotData) throws DataException, ForeignBlockchainException {
+		State tradeBotState = State.valueOf(tradeBotData.getStateValue());
+		if (tradeBotState == null) {
+			LOGGER.info(() -> String.format("Trade-bot entry for AT %s has invalid state?", tradeBotData.getAtAddress()));
+			return;
+		}
+
+		ATData atData = null;
+		CrossChainTradeData tradeData = null;
+
+		if (tradeBotState.requiresAtData) {
+			// Attempt to fetch AT data
+			atData = repository.getATRepository().fromATAddress(tradeBotData.getAtAddress());
+			if (atData == null) {
+				LOGGER.debug(() -> String.format("Unable to fetch trade AT %s from repository", tradeBotData.getAtAddress()));
+				return;
+			}
+
+			if (tradeBotState.requiresTradeData) {
+				tradeData = DogecoinACCTv3.getInstance().populateTradeData(repository, atData);
+				if (tradeData == null) {
+					LOGGER.warn(() -> String.format("Unable to fetch ACCT trade data for AT %s from repository", tradeBotData.getAtAddress()));
+					return;
+				}
+			}
+		}
+
+		switch (tradeBotState) {
+			case BOB_WAITING_FOR_AT_CONFIRM:
+				handleBobWaitingForAtConfirm(repository, tradeBotData);
+				break;
+
+			case BOB_WAITING_FOR_MESSAGE:
+				TradeBot.getInstance().updatePresence(repository, tradeBotData, tradeData);
+				handleBobWaitingForMessage(repository, tradeBotData, atData, tradeData);
+				break;
+
+			case ALICE_WAITING_FOR_AT_LOCK:
+				TradeBot.getInstance().updatePresence(repository, tradeBotData, tradeData);
+				handleAliceWaitingForAtLock(repository, tradeBotData, atData, tradeData);
+				break;
+
+			case BOB_WAITING_FOR_AT_REDEEM:
+				TradeBot.getInstance().updatePresence(repository, tradeBotData, tradeData);
+				handleBobWaitingForAtRedeem(repository, tradeBotData, atData, tradeData);
+				break;
+
+			case ALICE_DONE:
+			case BOB_DONE:
+				break;
+
+			case ALICE_REFUNDING_A:
+				TradeBot.getInstance().updatePresence(repository, tradeBotData, tradeData);
+				handleAliceRefundingP2shA(repository, tradeBotData, atData, tradeData);
+				break;
+
+			case ALICE_REFUNDED:
+			case BOB_REFUNDED:
+				break;
+		}
+	}
+
+	/**
+	 * Trade-bot is waiting for Bob's AT to deploy.
+	 * <p>
+	 * If AT is deployed, then trade-bot's next step is to wait for MESSAGE from Alice.
+	 */
+	private void handleBobWaitingForAtConfirm(Repository repository, TradeBotData tradeBotData) throws DataException {
+		if (!repository.getATRepository().exists(tradeBotData.getAtAddress())) {
+			if (NTP.getTime() - tradeBotData.getTimestamp() <= MAX_AT_CONFIRMATION_PERIOD)
+				return;
+
+			// We've waited ages for AT to be confirmed into a block but something has gone awry.
+			// After this long we assume transaction loss so give up with trade-bot entry too.
+			tradeBotData.setState(State.BOB_REFUNDED.name());
+			tradeBotData.setStateValue(State.BOB_REFUNDED.value);
+			tradeBotData.setTimestamp(NTP.getTime());
+			// We delete trade-bot entry here instead of saving, hence not using updateTradeBotState()
+			repository.getCrossChainRepository().delete(tradeBotData.getTradePrivateKey());
+			repository.saveChanges();
+
+			LOGGER.info(() -> String.format("AT %s never confirmed. Giving up on trade", tradeBotData.getAtAddress()));
+			TradeBot.notifyStateChange(tradeBotData);
+			return;
+		}
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_WAITING_FOR_MESSAGE,
+				() -> String.format("AT %s confirmed ready. Waiting for trade message", tradeBotData.getAtAddress()));
+	}
+
+	/**
+	 * Trade-bot is waiting for MESSAGE from Alice's trade-bot, containing Alice's trade info.
+	 * <p>
+	 * It's possible Bob has cancelling his trade offer, receiving an automatic QORT refund,
+	 * in which case trade-bot is done with this specific trade and finalizes on refunded state.
+	 * <p>
+	 * Assuming trade is still on offer, trade-bot checks the contents of MESSAGE from Alice's trade-bot.
+	 * <p>
+	 * Details from Alice are used to derive P2SH-A address and this is checked for funding balance.
+	 * <p>
+	 * Assuming P2SH-A has at least expected Dogecoin balance,
+	 * Bob's trade-bot constructs a zero-fee, PoW MESSAGE to send to Bob's AT with more trade details.
+	 * <p>
+	 * On processing this MESSAGE, Bob's AT should switch into 'TRADE' mode and only trade with Alice.
+	 * <p>
+	 * Trade-bot's next step is to wait for Alice to redeem the AT, which will allow Bob to
+	 * extract secret-A needed to redeem Alice's P2SH.
+	 * @throws ForeignBlockchainException
+	 */
+	private void handleBobWaitingForMessage(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		// If AT has finished then Bob likely cancelled his trade offer
+		if (atData.getIsFinished()) {
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_REFUNDED,
+					() -> String.format("AT %s cancelled - trading aborted", tradeBotData.getAtAddress()));
+			return;
+		}
+
+		Dogecoin dogecoin = Dogecoin.getInstance();
+
+		String address = tradeBotData.getTradeNativeAddress();
+		List<MessageTransactionData> messageTransactionsData = repository.getMessageRepository().getMessagesByParticipants(null, address, null, null, null);
+
+		for (MessageTransactionData messageTransactionData : messageTransactionsData) {
+			if (messageTransactionData.isText())
+				continue;
+
+			// We're expecting: HASH160(secret-A), Alice's Dogecoin pubkeyhash and lockTime-A
+			byte[] messageData = messageTransactionData.getData();
+			DogecoinACCTv3.OfferMessageData offerMessageData = DogecoinACCTv3.extractOfferMessageData(messageData);
+			if (offerMessageData == null)
+				continue;
+
+			byte[] aliceForeignPublicKeyHash = offerMessageData.partnerDogecoinPKH;
+			byte[] hashOfSecretA = offerMessageData.hashOfSecretA;
+			int lockTimeA = (int) offerMessageData.lockTimeA;
+			long messageTimestamp = messageTransactionData.getTimestamp();
+			int refundTimeout = DogecoinACCTv3.calcRefundTimeout(messageTimestamp, lockTimeA);
+
+			// Determine P2SH-A address and confirm funded
+			byte[] redeemScriptA = BitcoinyHTLC.buildScript(aliceForeignPublicKeyHash, lockTimeA, tradeBotData.getTradeForeignPublicKeyHash(), hashOfSecretA);
+			String p2shAddressA = dogecoin.deriveP2shAddress(redeemScriptA);
+
+			long feeTimestamp = calcFeeTimestamp(lockTimeA, crossChainTradeData.tradeTimeout);
+			long p2shFee = Dogecoin.getInstance().getP2shFee(feeTimestamp);
+			final long minimumAmountA = tradeBotData.getForeignAmount() + p2shFee;
+
+			BitcoinyHTLC.Status htlcStatusA = BitcoinyHTLC.determineHtlcStatus(dogecoin.getBlockchainProvider(), p2shAddressA, minimumAmountA);
+
+			switch (htlcStatusA) {
+				case UNFUNDED:
+				case FUNDING_IN_PROGRESS:
+					// There might be another MESSAGE from someone else with an actually funded P2SH-A...
+					continue;
+
+				case REDEEM_IN_PROGRESS:
+				case REDEEMED:
+					// We've already redeemed this?
+					TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_DONE,
+							() -> String.format("P2SH-A %s already spent? Assuming trade complete", p2shAddressA));
+					return;
+
+				case REFUND_IN_PROGRESS:
+				case REFUNDED:
+					// This P2SH-A is burnt, but there might be another MESSAGE from someone else with an actually funded P2SH-A...
+					continue;
+
+				case FUNDED:
+					// Fall-through out of switch...
+					break;
+			}
+
+			// Good to go - send MESSAGE to AT
+
+			String aliceNativeAddress = Crypto.toAddress(messageTransactionData.getCreatorPublicKey());
+
+			// Build outgoing message, padding each part to 32 bytes to make it easier for AT to consume
+			byte[] outgoingMessageData = DogecoinACCTv3.buildTradeMessage(aliceNativeAddress, aliceForeignPublicKeyHash, hashOfSecretA, lockTimeA, refundTimeout);
+			String messageRecipient = tradeBotData.getAtAddress();
+
+			boolean isMessageAlreadySent = repository.getMessageRepository().exists(tradeBotData.getTradeNativePublicKey(), messageRecipient, outgoingMessageData);
+			if (!isMessageAlreadySent) {
+				PrivateKeyAccount sender = new PrivateKeyAccount(repository, tradeBotData.getTradePrivateKey());
+				MessageTransaction outgoingMessageTransaction = MessageTransaction.build(repository, sender, Group.NO_GROUP, messageRecipient, outgoingMessageData, false, false);
+
+				outgoingMessageTransaction.computeNonce();
+				outgoingMessageTransaction.sign(sender);
+
+				// reset repository state to prevent deadlock
+				repository.discardChanges();
+				ValidationResult result = outgoingMessageTransaction.importAsUnconfirmed();
+
+				if (result != ValidationResult.OK) {
+					LOGGER.warn(() -> String.format("Unable to send MESSAGE to AT %s: %s", messageRecipient, result.name()));
+					return;
+				}
+			}
+
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_WAITING_FOR_AT_REDEEM,
+					() -> String.format("Locked AT %s to %s. Waiting for AT redeem", tradeBotData.getAtAddress(), aliceNativeAddress));
+
+			return;
+		}
+	}
+
+	/**
+	 * Trade-bot is waiting for Bob's AT to switch to TRADE mode and lock trade to Alice only.
+	 * <p>
+	 * It's possible that Bob has cancelled his trade offer in the mean time, or that somehow
+	 * this process has taken so long that we've reached P2SH-A's locktime, or that someone else
+	 * has managed to trade with Bob. In any of these cases, trade-bot switches to begin the refunding process.
+	 * <p>
+	 * Assuming Bob's AT is locked to Alice, trade-bot checks AT's state data to make sure it is correct.
+	 * <p>
+	 * If all is well, trade-bot then redeems AT using Alice's secret-A, releasing Bob's QORT to Alice.
+	 * <p>
+	 * In revealing a valid secret-A, Bob can then redeem the DOGE funds from P2SH-A.
+	 * <p>
+	 * @throws ForeignBlockchainException
+	 */
+	private void handleAliceWaitingForAtLock(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		if (aliceUnexpectedState(repository, tradeBotData, atData, crossChainTradeData))
+			return;
+
+		Dogecoin dogecoin = Dogecoin.getInstance();
+		int lockTimeA = tradeBotData.getLockTimeA();
+
+		// Refund P2SH-A if we've passed lockTime-A
+		if (NTP.getTime() >= lockTimeA * 1000L) {
+			byte[] redeemScriptA = BitcoinyHTLC.buildScript(tradeBotData.getTradeForeignPublicKeyHash(), lockTimeA, crossChainTradeData.creatorForeignPKH, tradeBotData.getHashOfSecret());
+			String p2shAddressA = dogecoin.deriveP2shAddress(redeemScriptA);
+
+			long feeTimestamp = calcFeeTimestamp(lockTimeA, crossChainTradeData.tradeTimeout);
+			long p2shFee = Dogecoin.getInstance().getP2shFee(feeTimestamp);
+			long minimumAmountA = crossChainTradeData.expectedForeignAmount + p2shFee;
+
+			BitcoinyHTLC.Status htlcStatusA = BitcoinyHTLC.determineHtlcStatus(dogecoin.getBlockchainProvider(), p2shAddressA, minimumAmountA);
+
+			switch (htlcStatusA) {
+				case UNFUNDED:
+				case FUNDING_IN_PROGRESS:
+				case FUNDED:
+					break;
+
+				case REDEEM_IN_PROGRESS:
+				case REDEEMED:
+					// Already redeemed?
+					TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_DONE,
+							() -> String.format("P2SH-A %s already spent? Assuming trade completed", p2shAddressA));
+					return;
+
+				case REFUND_IN_PROGRESS:
+				case REFUNDED:
+					TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDED,
+							() -> String.format("P2SH-A %s already refunded. Trade aborted", p2shAddressA));
+					return;
+
+			}
+
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDING_A,
+					() -> atData.getIsFinished()
+					? String.format("AT %s cancelled. Refunding P2SH-A %s - aborting trade", tradeBotData.getAtAddress(), p2shAddressA)
+					: String.format("LockTime-A reached, refunding P2SH-A %s - aborting trade", p2shAddressA));
+
+			return;
+		}
+
+		// We're waiting for AT to be in TRADE mode
+		if (crossChainTradeData.mode != AcctMode.TRADING)
+			return;
+
+		// AT is in TRADE mode and locked to us as checked by aliceUnexpectedState() above
+
+		// Find our MESSAGE to AT from previous state
+		List<MessageTransactionData> messageTransactionsData = repository.getMessageRepository().getMessagesByParticipants(tradeBotData.getTradeNativePublicKey(),
+				crossChainTradeData.qortalCreatorTradeAddress, null, null, null);
+		if (messageTransactionsData == null || messageTransactionsData.isEmpty()) {
+			LOGGER.warn(() -> String.format("Unable to find our message to trade creator %s?", crossChainTradeData.qortalCreatorTradeAddress));
+			return;
+		}
+
+		long recipientMessageTimestamp = messageTransactionsData.get(0).getTimestamp();
+		int refundTimeout = DogecoinACCTv3.calcRefundTimeout(recipientMessageTimestamp, lockTimeA);
+
+		// Our calculated refundTimeout should match AT's refundTimeout
+		if (refundTimeout != crossChainTradeData.refundTimeout) {
+			LOGGER.debug(() -> String.format("Trade AT refundTimeout '%d' doesn't match our refundTimeout '%d'", crossChainTradeData.refundTimeout, refundTimeout));
+			// We'll eventually refund
+			return;
+		}
+
+		// We're good to redeem AT
+
+		// Send 'redeem' MESSAGE to AT using both secret
+		byte[] secretA = tradeBotData.getSecret();
+		String qortalReceivingAddress = Base58.encode(tradeBotData.getReceivingAccountInfo()); // Actually contains whole address, not just PKH
+		byte[] messageData = DogecoinACCTv3.buildRedeemMessage(secretA, qortalReceivingAddress);
+		String messageRecipient = tradeBotData.getAtAddress();
+
+		boolean isMessageAlreadySent = repository.getMessageRepository().exists(tradeBotData.getTradeNativePublicKey(), messageRecipient, messageData);
+		if (!isMessageAlreadySent) {
+			PrivateKeyAccount sender = new PrivateKeyAccount(repository, tradeBotData.getTradePrivateKey());
+			MessageTransaction messageTransaction = MessageTransaction.build(repository, sender, Group.NO_GROUP, messageRecipient, messageData, false, false);
+
+			messageTransaction.computeNonce();
+			messageTransaction.sign(sender);
+
+			// Reset repository state to prevent deadlock
+			repository.discardChanges();
+			ValidationResult result = messageTransaction.importAsUnconfirmed();
+
+			if (result != ValidationResult.OK) {
+				LOGGER.warn(() -> String.format("Unable to send MESSAGE to AT %s: %s", messageRecipient, result.name()));
+				return;
+			}
+		}
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_DONE,
+				() -> String.format("Redeeming AT %s. Funds should arrive at %s",
+						tradeBotData.getAtAddress(), qortalReceivingAddress));
+	}
+
+	/**
+	 * Trade-bot is waiting for Alice to redeem Bob's AT, thus revealing secret-A which is required to spend the DOGE funds from P2SH-A.
+	 * <p>
+	 * It's possible that Bob's AT has reached its trading timeout and automatically refunded QORT back to Bob. In which case,
+	 * trade-bot is done with this specific trade and finalizes in refunded state.
+	 * <p>
+	 * Assuming trade-bot can extract a valid secret-A from Alice's MESSAGE then trade-bot uses that to redeem the DOGE funds from P2SH-A
+	 * to Bob's 'foreign'/Dogecoin trade legacy-format address, as derived from trade private key.
+	 * <p>
+	 * (This could potentially be 'improved' to send DOGE to any address of Bob's choosing by changing the transaction output).
+	 * <p>
+	 * If trade-bot successfully broadcasts the transaction, then this specific trade is done.
+	 * @throws ForeignBlockchainException
+	 */
+	private void handleBobWaitingForAtRedeem(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		// AT should be 'finished' once Alice has redeemed QORT funds
+		if (!atData.getIsFinished())
+			// Not finished yet
+			return;
+
+		// If AT is REFUNDED or CANCELLED then something has gone wrong
+		if (crossChainTradeData.mode == AcctMode.REFUNDED || crossChainTradeData.mode == AcctMode.CANCELLED) {
+			// Alice hasn't redeemed the QORT, so there is no point in trying to redeem the DOGE
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_REFUNDED,
+					() -> String.format("AT %s has auto-refunded - trade aborted", tradeBotData.getAtAddress()));
+
+			return;
+		}
+
+		byte[] secretA = DogecoinACCTv3.getInstance().findSecretA(repository, crossChainTradeData);
+		if (secretA == null) {
+			LOGGER.debug(() -> String.format("Unable to find secret-A from redeem message to AT %s?", tradeBotData.getAtAddress()));
+			return;
+		}
+
+		// Use secret-A to redeem P2SH-A
+
+		Dogecoin dogecoin = Dogecoin.getInstance();
+
+		byte[] receivingAccountInfo = tradeBotData.getReceivingAccountInfo();
+		int lockTimeA = crossChainTradeData.lockTimeA;
+		byte[] redeemScriptA = BitcoinyHTLC.buildScript(crossChainTradeData.partnerForeignPKH, lockTimeA, crossChainTradeData.creatorForeignPKH, crossChainTradeData.hashOfSecretA);
+		String p2shAddressA = dogecoin.deriveP2shAddress(redeemScriptA);
+
+		// Fee for redeem/refund is subtracted from P2SH-A balance.
+		long feeTimestamp = calcFeeTimestamp(lockTimeA, crossChainTradeData.tradeTimeout);
+		long p2shFee = Dogecoin.getInstance().getP2shFee(feeTimestamp);
+		long minimumAmountA = crossChainTradeData.expectedForeignAmount + p2shFee;
+		BitcoinyHTLC.Status htlcStatusA = BitcoinyHTLC.determineHtlcStatus(dogecoin.getBlockchainProvider(), p2shAddressA, minimumAmountA);
+
+		switch (htlcStatusA) {
+			case UNFUNDED:
+			case FUNDING_IN_PROGRESS:
+				// P2SH-A suddenly not funded? Our best bet at this point is to hope for AT auto-refund
+				return;
+
+			case REDEEM_IN_PROGRESS:
+			case REDEEMED:
+				// Double-check that we have redeemed P2SH-A...
+				break;
+
+			case REFUND_IN_PROGRESS:
+			case REFUNDED:
+				// Wait for AT to auto-refund
+				return;
+
+			case FUNDED: {
+				Coin redeemAmount = Coin.valueOf(crossChainTradeData.expectedForeignAmount);
+				ECKey redeemKey = ECKey.fromPrivate(tradeBotData.getTradePrivateKey());
+				List<TransactionOutput> fundingOutputs = dogecoin.getUnspentOutputs(p2shAddressA);
+
+				Transaction p2shRedeemTransaction = BitcoinyHTLC.buildRedeemTransaction(dogecoin.getNetworkParameters(), redeemAmount, redeemKey,
+						fundingOutputs, redeemScriptA, secretA, receivingAccountInfo);
+
+				dogecoin.broadcastTransaction(p2shRedeemTransaction);
+				break;
+			}
+		}
+
+		String receivingAddress = dogecoin.pkhToAddress(receivingAccountInfo);
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_DONE,
+				() -> String.format("P2SH-A %s redeemed. Funds should arrive at %s", tradeBotData.getAtAddress(), receivingAddress));
+	}
+
+	/**
+	 * Trade-bot is attempting to refund P2SH-A.
+	 * @throws ForeignBlockchainException
+	 */
+	private void handleAliceRefundingP2shA(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		int lockTimeA = tradeBotData.getLockTimeA();
+
+		// We can't refund P2SH-A until lockTime-A has passed
+		if (NTP.getTime() <= lockTimeA * 1000L)
+			return;
+
+		Dogecoin dogecoin = Dogecoin.getInstance();
+
+		// We can't refund P2SH-A until median block time has passed lockTime-A (see BIP113)
+		int medianBlockTime = dogecoin.getMedianBlockTime();
+		if (medianBlockTime <= lockTimeA)
+			return;
+
+		byte[] redeemScriptA = BitcoinyHTLC.buildScript(tradeBotData.getTradeForeignPublicKeyHash(), lockTimeA, crossChainTradeData.creatorForeignPKH, tradeBotData.getHashOfSecret());
+		String p2shAddressA = dogecoin.deriveP2shAddress(redeemScriptA);
+
+		// Fee for redeem/refund is subtracted from P2SH-A balance.
+		long feeTimestamp = calcFeeTimestamp(lockTimeA, crossChainTradeData.tradeTimeout);
+		long p2shFee = Dogecoin.getInstance().getP2shFee(feeTimestamp);
+		long minimumAmountA = crossChainTradeData.expectedForeignAmount + p2shFee;
+		BitcoinyHTLC.Status htlcStatusA = BitcoinyHTLC.determineHtlcStatus(dogecoin.getBlockchainProvider(), p2shAddressA, minimumAmountA);
+
+		switch (htlcStatusA) {
+			case UNFUNDED:
+			case FUNDING_IN_PROGRESS:
+				// Still waiting for P2SH-A to be funded...
+				return;
+
+			case REDEEM_IN_PROGRESS:
+			case REDEEMED:
+				// Too late!
+				TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_DONE,
+						() -> String.format("P2SH-A %s already spent!", p2shAddressA));
+				return;
+
+			case REFUND_IN_PROGRESS:
+			case REFUNDED:
+				break;
+
+			case FUNDED:{
+				Coin refundAmount = Coin.valueOf(crossChainTradeData.expectedForeignAmount);
+				ECKey refundKey = ECKey.fromPrivate(tradeBotData.getTradePrivateKey());
+				List<TransactionOutput> fundingOutputs = dogecoin.getUnspentOutputs(p2shAddressA);
+
+				// Determine receive address for refund
+				String receiveAddress = dogecoin.getUnusedReceiveAddress(tradeBotData.getForeignKey());
+				Address receiving = Address.fromString(dogecoin.getNetworkParameters(), receiveAddress);
+
+				Transaction p2shRefundTransaction = BitcoinyHTLC.buildRefundTransaction(dogecoin.getNetworkParameters(), refundAmount, refundKey,
+						fundingOutputs, redeemScriptA, lockTimeA, receiving.getHash());
+
+				dogecoin.broadcastTransaction(p2shRefundTransaction);
+				break;
+			}
+		}
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDED,
+				() -> String.format("LockTime-A reached. Refunded P2SH-A %s. Trade aborted", p2shAddressA));
+	}
+
+	/**
+	 * Returns true if Alice finds AT unexpectedly cancelled, refunded, redeemed or locked to someone else.
+	 * <p>
+	 * Will automatically update trade-bot state to <tt>ALICE_REFUNDING_A</tt> or <tt>ALICE_DONE</tt> as necessary.
+	 * 
+	 * @throws DataException
+	 * @throws ForeignBlockchainException
+	 */
+	private boolean aliceUnexpectedState(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		// This is OK
+		if (!atData.getIsFinished() && crossChainTradeData.mode == AcctMode.OFFERING)
+			return false;
+
+		boolean isAtLockedToUs = tradeBotData.getTradeNativeAddress().equals(crossChainTradeData.qortalPartnerAddress);
+
+		if (!atData.getIsFinished() && crossChainTradeData.mode == AcctMode.TRADING)
+			if (isAtLockedToUs) {
+				// AT is trading with us - OK
+				return false;
+			} else {
+				TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDING_A,
+						() -> String.format("AT %s trading with someone else: %s. Refunding & aborting trade", tradeBotData.getAtAddress(), crossChainTradeData.qortalPartnerAddress));
+
+				return true;
+			}
+
+		if (atData.getIsFinished() && crossChainTradeData.mode == AcctMode.REDEEMED && isAtLockedToUs) {
+			// We've redeemed already?
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_DONE,
+					() -> String.format("AT %s already redeemed by us. Trade completed", tradeBotData.getAtAddress()));
+		} else {
+			// Any other state is not good, so start defensive refund
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDING_A,
+					() -> String.format("AT %s cancelled/refunded/redeemed by someone else/invalid state. Refunding & aborting trade", tradeBotData.getAtAddress()));
+		}
+
+		return true;
+	}
+
+	private long calcFeeTimestamp(int lockTimeA, int tradeTimeout) {
+		return (lockTimeA - tradeTimeout * 60) * 1000L;
+	}
+
+}

src/main/java/org/qortal/controller/tradebot/LitecoinACCTv1TradeBot.java

@@ -212,7 +212,7 @@ public class LitecoinACCTv1TradeBot implements AcctTradeBot {
 		TradeBot.updateTradeBotState(repository, tradeBotData, () -> String.format("Built AT %s. Waiting for deployment", atAddress));
 
 		// Attempt to backup the trade bot data
-		TradeBot.backupTradeBotData(repository);
+		TradeBot.backupTradeBotData(repository, null);
 
 		// Return to user for signing and broadcast as we don't have their Qortal private key
 		try {
@@ -287,7 +287,8 @@ public class LitecoinACCTv1TradeBot implements AcctTradeBot {
 				crossChainTradeData.expectedForeignAmount, xprv58, null, lockTimeA, receivingPublicKeyHash);
 
 		// Attempt to backup the trade bot data
-		TradeBot.backupTradeBotData(repository);
+		// Include tradeBotData as an additional parameter, since it's not in the repository yet
+		TradeBot.backupTradeBotData(repository, Arrays.asList(tradeBotData));
 
 		// Check we have enough funds via xprv58 to fund P2SH to cover expectedForeignAmount
 		long p2shFee;
@@ -364,6 +365,7 @@ public class LitecoinACCTv1TradeBot implements AcctTradeBot {
 			case BOB_DONE:
 			case ALICE_REFUNDED:
 			case BOB_REFUNDED:
+			case ALICE_REFUNDING_A:
 				return true;
 
 			default:

src/main/java/org/qortal/controller/tradebot/LitecoinACCTv2TradeBot.java

@@ -0,0 +1,885 @@
+package org.qortal.controller.tradebot;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.bitcoinj.core.*;
+import org.bitcoinj.script.Script.ScriptType;
+import org.qortal.account.PrivateKeyAccount;
+import org.qortal.account.PublicKeyAccount;
+import org.qortal.api.model.crosschain.TradeBotCreateRequest;
+import org.qortal.asset.Asset;
+import org.qortal.crosschain.*;
+import org.qortal.crypto.Crypto;
+import org.qortal.data.at.ATData;
+import org.qortal.data.crosschain.CrossChainTradeData;
+import org.qortal.data.crosschain.TradeBotData;
+import org.qortal.data.transaction.BaseTransactionData;
+import org.qortal.data.transaction.DeployAtTransactionData;
+import org.qortal.data.transaction.MessageTransactionData;
+import org.qortal.group.Group;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.transaction.DeployAtTransaction;
+import org.qortal.transaction.MessageTransaction;
+import org.qortal.transaction.Transaction.ValidationResult;
+import org.qortal.transform.TransformationException;
+import org.qortal.transform.transaction.DeployAtTransactionTransformer;
+import org.qortal.utils.Base58;
+import org.qortal.utils.NTP;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import static java.util.Arrays.stream;
+import static java.util.stream.Collectors.toMap;
+
+/**
+ * Performing cross-chain trading steps on behalf of user.
+ * <p>
+ * We deal with three different independent state-spaces here:
+ * <ul>
+ * 	<li>Qortal blockchain</li>
+ * 	<li>Foreign blockchain</li>
+ * 	<li>Trade-bot entries</li>
+ * </ul>
+ */
+public class LitecoinACCTv2TradeBot implements AcctTradeBot {
+
+	private static final Logger LOGGER = LogManager.getLogger(LitecoinACCTv2TradeBot.class);
+
+	public enum State implements TradeBot.StateNameAndValueSupplier {
+		BOB_WAITING_FOR_AT_CONFIRM(10, false, false),
+		BOB_WAITING_FOR_MESSAGE(15, true, true),
+		BOB_WAITING_FOR_AT_REDEEM(25, true, true),
+		BOB_DONE(30, false, false),
+		BOB_REFUNDED(35, false, false),
+
+		ALICE_WAITING_FOR_AT_LOCK(85, true, true),
+		ALICE_DONE(95, false, false),
+		ALICE_REFUNDING_A(105, true, true),
+		ALICE_REFUNDED(110, false, false);
+
+		private static final Map<Integer, State> map = stream(State.values()).collect(toMap(state -> state.value, state -> state));
+
+		public final int value;
+		public final boolean requiresAtData;
+		public final boolean requiresTradeData;
+
+		State(int value, boolean requiresAtData, boolean requiresTradeData) {
+			this.value = value;
+			this.requiresAtData = requiresAtData;
+			this.requiresTradeData = requiresTradeData;
+		}
+
+		public static State valueOf(int value) {
+			return map.get(value);
+		}
+
+		@Override
+		public String getState() {
+			return this.name();
+		}
+
+		@Override
+		public int getStateValue() {
+			return this.value;
+		}
+	}
+
+	/** Maximum time Bob waits for his AT creation transaction to be confirmed into a block. (milliseconds) */
+	private static final long MAX_AT_CONFIRMATION_PERIOD = 24 * 60 * 60 * 1000L; // ms
+
+	private static LitecoinACCTv2TradeBot instance;
+
+	private final List<String> endStates = Arrays.asList(State.BOB_DONE, State.BOB_REFUNDED, State.ALICE_DONE, State.ALICE_REFUNDING_A, State.ALICE_REFUNDED).stream()
+			.map(State::name)
+			.collect(Collectors.toUnmodifiableList());
+
+	private LitecoinACCTv2TradeBot() {
+	}
+
+	public static synchronized LitecoinACCTv2TradeBot getInstance() {
+		if (instance == null)
+			instance = new LitecoinACCTv2TradeBot();
+
+		return instance;
+	}
+
+	@Override
+	public List<String> getEndStates() {
+		return this.endStates;
+	}
+
+	/**
+	 * Creates a new trade-bot entry from the "Bob" viewpoint, i.e. OFFERing QORT in exchange for LTC.
+	 * <p>
+	 * Generates:
+	 * <ul>
+	 * 	<li>new 'trade' private key</li>
+	 * </ul>
+	 * Derives:
+	 * <ul>
+	 * 	<li>'native' (as in Qortal) public key, public key hash, address (starting with Q)</li>
+	 * 	<li>'foreign' (as in Litecoin) public key, public key hash</li>
+	 * </ul>
+	 * A Qortal AT is then constructed including the following as constants in the 'data segment':
+	 * <ul>
+	 * 	<li>'native'/Qortal 'trade' address - used as a MESSAGE contact</li>
+	 * 	<li>'foreign'/Litecoin public key hash - used by Alice's P2SH scripts to allow redeem</li>
+	 * 	<li>QORT amount on offer by Bob</li>
+	 * 	<li>LTC amount expected in return by Bob (from Alice)</li>
+	 * 	<li>trading timeout, in case things go wrong and everyone needs to refund</li>
+	 * </ul>
+	 * Returns a DEPLOY_AT transaction that needs to be signed and broadcast to the Qortal network.
+	 * <p>
+	 * Trade-bot will wait for Bob's AT to be deployed before taking next step.
+	 * <p>
+	 * @param repository
+	 * @param tradeBotCreateRequest
+	 * @return raw, unsigned DEPLOY_AT transaction
+	 * @throws DataException
+	 */
+	public byte[] createTrade(Repository repository, TradeBotCreateRequest tradeBotCreateRequest) throws DataException {
+		byte[] tradePrivateKey = TradeBot.generateTradePrivateKey();
+
+		byte[] tradeNativePublicKey = TradeBot.deriveTradeNativePublicKey(tradePrivateKey);
+		byte[] tradeNativePublicKeyHash = Crypto.hash160(tradeNativePublicKey);
+		String tradeNativeAddress = Crypto.toAddress(tradeNativePublicKey);
+
+		byte[] tradeForeignPublicKey = TradeBot.deriveTradeForeignPublicKey(tradePrivateKey);
+		byte[] tradeForeignPublicKeyHash = Crypto.hash160(tradeForeignPublicKey);
+
+		// Convert Litecoin receiving address into public key hash (we only support P2PKH at this time)
+		Address litecoinReceivingAddress;
+		try {
+			litecoinReceivingAddress = Address.fromString(Litecoin.getInstance().getNetworkParameters(), tradeBotCreateRequest.receivingAddress);
+		} catch (AddressFormatException e) {
+			throw new DataException("Unsupported Litecoin receiving address: " + tradeBotCreateRequest.receivingAddress);
+		}
+		if (litecoinReceivingAddress.getOutputScriptType() != ScriptType.P2PKH)
+			throw new DataException("Unsupported Litecoin receiving address: " + tradeBotCreateRequest.receivingAddress);
+
+		byte[] litecoinReceivingAccountInfo = litecoinReceivingAddress.getHash();
+
+		PublicKeyAccount creator = new PublicKeyAccount(repository, tradeBotCreateRequest.creatorPublicKey);
+
+		// Deploy AT
+		long timestamp = NTP.getTime();
+		byte[] reference = creator.getLastReference();
+		long fee = 0L;
+		byte[] signature = null;
+		BaseTransactionData baseTransactionData = new BaseTransactionData(timestamp, Group.NO_GROUP, reference, creator.getPublicKey(), fee, signature);
+
+		String name = "QORT/LTC ACCT";
+		String description = "QORT/LTC cross-chain trade";
+		String aTType = "ACCT";
+		String tags = "ACCT QORT LTC";
+		byte[] creationBytes = LitecoinACCTv2.buildQortalAT(tradeNativeAddress, tradeForeignPublicKeyHash, tradeBotCreateRequest.qortAmount,
+				tradeBotCreateRequest.foreignAmount, tradeBotCreateRequest.tradeTimeout);
+		long amount = tradeBotCreateRequest.fundingQortAmount;
+
+		DeployAtTransactionData deployAtTransactionData = new DeployAtTransactionData(baseTransactionData, name, description, aTType, tags, creationBytes, amount, Asset.QORT);
+
+		DeployAtTransaction deployAtTransaction = new DeployAtTransaction(repository, deployAtTransactionData);
+		fee = deployAtTransaction.calcRecommendedFee();
+		deployAtTransactionData.setFee(fee);
+
+		DeployAtTransaction.ensureATAddress(deployAtTransactionData);
+		String atAddress = deployAtTransactionData.getAtAddress();
+
+		TradeBotData tradeBotData =  new TradeBotData(tradePrivateKey, LitecoinACCTv2.NAME,
+				State.BOB_WAITING_FOR_AT_CONFIRM.name(), State.BOB_WAITING_FOR_AT_CONFIRM.value,
+				creator.getAddress(), atAddress, timestamp, tradeBotCreateRequest.qortAmount,
+				tradeNativePublicKey, tradeNativePublicKeyHash, tradeNativeAddress,
+				null, null,
+				SupportedBlockchain.LITECOIN.name(),
+				tradeForeignPublicKey, tradeForeignPublicKeyHash,
+				tradeBotCreateRequest.foreignAmount, null, null, null, litecoinReceivingAccountInfo);
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, () -> String.format("Built AT %s. Waiting for deployment", atAddress));
+
+		// Attempt to backup the trade bot data
+		TradeBot.backupTradeBotData(repository, null);
+
+		// Return to user for signing and broadcast as we don't have their Qortal private key
+		try {
+			return DeployAtTransactionTransformer.toBytes(deployAtTransactionData);
+		} catch (TransformationException e) {
+			throw new DataException("Failed to transform DEPLOY_AT transaction?", e);
+		}
+	}
+
+	/**
+	 * Creates a trade-bot entry from the 'Alice' viewpoint, i.e. matching LTC to an existing offer.
+	 * <p>
+	 * Requires a chosen trade offer from Bob, passed by <tt>crossChainTradeData</tt>
+	 * and access to a Litecoin wallet via <tt>xprv58</tt>.
+	 * <p>
+	 * The <tt>crossChainTradeData</tt> contains the current trade offer state
+	 * as extracted from the AT's data segment.
+	 * <p>
+	 * Access to a funded wallet is via a Litecoin BIP32 hierarchical deterministic key,
+	 * passed via <tt>xprv58</tt>.
+	 * <b>This key will be stored in your node's database</b>
+	 * to allow trade-bot to create/fund the necessary P2SH transactions!
+	 * However, due to the nature of BIP32 keys, it is possible to give the trade-bot
+	 * only a subset of wallet access (see BIP32 for more details).
+	 * <p>
+	 * As an example, the xprv58 can be extract from a <i>legacy, password-less</i>
+	 * Electrum wallet by going to the console tab and entering:<br>
+	 * <tt>wallet.keystore.xprv</tt><br>
+	 * which should result in a base58 string starting with either 'xprv' (for Litecoin main-net)
+	 * or 'tprv' for (Litecoin test-net).
+	 * <p>
+	 * It is envisaged that the value in <tt>xprv58</tt> will actually come from a Qortal-UI-managed wallet.
+	 * <p>
+	 * If sufficient funds are available, <b>this method will actually fund the P2SH-A</b>
+	 * with the Litecoin amount expected by 'Bob'.
+	 * <p>
+	 * If the Litecoin transaction is successfully broadcast to the network then
+	 * we also send a MESSAGE to Bob's trade-bot to let them know.
+	 * <p>
+	 * The trade-bot entry is saved to the repository and the cross-chain trading process commences.
+	 * <p>
+	 * @param repository
+	 * @param crossChainTradeData chosen trade OFFER that Alice wants to match
+	 * @param xprv58 funded wallet xprv in base58
+	 * @return true if P2SH-A funding transaction successfully broadcast to Litecoin network, false otherwise
+	 * @throws DataException
+	 */
+	public ResponseResult startResponse(Repository repository, ATData atData, ACCT acct, CrossChainTradeData crossChainTradeData, String xprv58, String receivingAddress) throws DataException {
+		byte[] tradePrivateKey = TradeBot.generateTradePrivateKey();
+		byte[] secretA = TradeBot.generateSecret();
+		byte[] hashOfSecretA = Crypto.hash160(secretA);
+
+		byte[] tradeNativePublicKey = TradeBot.deriveTradeNativePublicKey(tradePrivateKey);
+		byte[] tradeNativePublicKeyHash = Crypto.hash160(tradeNativePublicKey);
+		String tradeNativeAddress = Crypto.toAddress(tradeNativePublicKey);
+
+		byte[] tradeForeignPublicKey = TradeBot.deriveTradeForeignPublicKey(tradePrivateKey);
+		byte[] tradeForeignPublicKeyHash = Crypto.hash160(tradeForeignPublicKey);
+		byte[] receivingPublicKeyHash = Base58.decode(receivingAddress); // Actually the whole address, not just PKH
+
+		// We need to generate lockTime-A: add tradeTimeout to now
+		long now = NTP.getTime();
+		int lockTimeA = crossChainTradeData.tradeTimeout * 60 + (int) (now / 1000L);
+
+		TradeBotData tradeBotData =  new TradeBotData(tradePrivateKey, LitecoinACCTv2.NAME,
+				State.ALICE_WAITING_FOR_AT_LOCK.name(), State.ALICE_WAITING_FOR_AT_LOCK.value,
+				receivingAddress, crossChainTradeData.qortalAtAddress, now, crossChainTradeData.qortAmount,
+				tradeNativePublicKey, tradeNativePublicKeyHash, tradeNativeAddress,
+				secretA, hashOfSecretA,
+				SupportedBlockchain.LITECOIN.name(),
+				tradeForeignPublicKey, tradeForeignPublicKeyHash,
+				crossChainTradeData.expectedForeignAmount, xprv58, null, lockTimeA, receivingPublicKeyHash);
+
+		// Attempt to backup the trade bot data
+		// Include tradeBotData as an additional parameter, since it's not in the repository yet
+		TradeBot.backupTradeBotData(repository, Arrays.asList(tradeBotData));
+
+		// Check we have enough funds via xprv58 to fund P2SH to cover expectedForeignAmount
+		long p2shFee;
+		try {
+			p2shFee = Litecoin.getInstance().getP2shFee(now);
+		} catch (ForeignBlockchainException e) {
+			LOGGER.debug("Couldn't estimate Litecoin fees?");
+			return ResponseResult.NETWORK_ISSUE;
+		}
+
+		// Fee for redeem/refund is subtracted from P2SH-A balance.
+		// Do not include fee for funding transaction as this is covered by buildSpend()
+		long amountA = crossChainTradeData.expectedForeignAmount + p2shFee /*redeeming/refunding P2SH-A*/;
+
+		// P2SH-A to be funded
+		byte[] redeemScriptBytes = BitcoinyHTLC.buildScript(tradeForeignPublicKeyHash, lockTimeA, crossChainTradeData.creatorForeignPKH, hashOfSecretA);
+		String p2shAddress = Litecoin.getInstance().deriveP2shAddress(redeemScriptBytes);
+
+		// Build transaction for funding P2SH-A
+		Transaction p2shFundingTransaction = Litecoin.getInstance().buildSpend(tradeBotData.getForeignKey(), p2shAddress, amountA);
+		if (p2shFundingTransaction == null) {
+			LOGGER.debug("Unable to build P2SH-A funding transaction - lack of funds?");
+			return ResponseResult.BALANCE_ISSUE;
+		}
+
+		try {
+			Litecoin.getInstance().broadcastTransaction(p2shFundingTransaction);
+		} catch (ForeignBlockchainException e) {
+			// We couldn't fund P2SH-A at this time
+			LOGGER.debug("Couldn't broadcast P2SH-A funding transaction?");
+			return ResponseResult.NETWORK_ISSUE;
+		}
+
+		// Attempt to send MESSAGE to Bob's Qortal trade address
+		byte[] messageData = LitecoinACCTv2.buildOfferMessage(tradeBotData.getTradeForeignPublicKeyHash(), tradeBotData.getHashOfSecret(), tradeBotData.getLockTimeA());
+		String messageRecipient = crossChainTradeData.qortalCreatorTradeAddress;
+
+		boolean isMessageAlreadySent = repository.getMessageRepository().exists(tradeBotData.getTradeNativePublicKey(), messageRecipient, messageData);
+		if (!isMessageAlreadySent) {
+			PrivateKeyAccount sender = new PrivateKeyAccount(repository, tradeBotData.getTradePrivateKey());
+			MessageTransaction messageTransaction = MessageTransaction.build(repository, sender, Group.NO_GROUP, messageRecipient, messageData, false, false);
+
+			messageTransaction.computeNonce();
+			messageTransaction.sign(sender);
+
+			// reset repository state to prevent deadlock
+			repository.discardChanges();
+			ValidationResult result = messageTransaction.importAsUnconfirmed();
+
+			if (result != ValidationResult.OK) {
+				LOGGER.warn(() -> String.format("Unable to send MESSAGE to Bob's trade-bot %s: %s", messageRecipient, result.name()));
+				return ResponseResult.NETWORK_ISSUE;
+			}
+		}
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, () -> String.format("Funding P2SH-A %s. Messaged Bob. Waiting for AT-lock", p2shAddress));
+
+		return ResponseResult.OK;
+	}
+
+	@Override
+	public boolean canDelete(Repository repository, TradeBotData tradeBotData) throws DataException {
+		State tradeBotState = State.valueOf(tradeBotData.getStateValue());
+		if (tradeBotState == null)
+			return true;
+
+		// If the AT doesn't exist then we might as well let the user tidy up
+		if (!repository.getATRepository().exists(tradeBotData.getAtAddress()))
+			return true;
+
+		switch (tradeBotState) {
+			case BOB_WAITING_FOR_AT_CONFIRM:
+			case ALICE_DONE:
+			case BOB_DONE:
+			case ALICE_REFUNDED:
+			case BOB_REFUNDED:
+			case ALICE_REFUNDING_A:
+				return true;
+
+			default:
+				return false;
+		}
+	}
+
+	@Override
+	public void progress(Repository repository, TradeBotData tradeBotData) throws DataException, ForeignBlockchainException {
+		State tradeBotState = State.valueOf(tradeBotData.getStateValue());
+		if (tradeBotState == null) {
+			LOGGER.info(() -> String.format("Trade-bot entry for AT %s has invalid state?", tradeBotData.getAtAddress()));
+			return;
+		}
+
+		ATData atData = null;
+		CrossChainTradeData tradeData = null;
+
+		if (tradeBotState.requiresAtData) {
+			// Attempt to fetch AT data
+			atData = repository.getATRepository().fromATAddress(tradeBotData.getAtAddress());
+			if (atData == null) {
+				LOGGER.debug(() -> String.format("Unable to fetch trade AT %s from repository", tradeBotData.getAtAddress()));
+				return;
+			}
+
+			if (tradeBotState.requiresTradeData) {
+				tradeData = LitecoinACCTv2.getInstance().populateTradeData(repository, atData);
+				if (tradeData == null) {
+					LOGGER.warn(() -> String.format("Unable to fetch ACCT trade data for AT %s from repository", tradeBotData.getAtAddress()));
+					return;
+				}
+			}
+		}
+
+		switch (tradeBotState) {
+			case BOB_WAITING_FOR_AT_CONFIRM:
+				handleBobWaitingForAtConfirm(repository, tradeBotData);
+				break;
+
+			case BOB_WAITING_FOR_MESSAGE:
+				TradeBot.getInstance().updatePresence(repository, tradeBotData, tradeData);
+				handleBobWaitingForMessage(repository, tradeBotData, atData, tradeData);
+				break;
+
+			case ALICE_WAITING_FOR_AT_LOCK:
+				TradeBot.getInstance().updatePresence(repository, tradeBotData, tradeData);
+				handleAliceWaitingForAtLock(repository, tradeBotData, atData, tradeData);
+				break;
+
+			case BOB_WAITING_FOR_AT_REDEEM:
+				TradeBot.getInstance().updatePresence(repository, tradeBotData, tradeData);
+				handleBobWaitingForAtRedeem(repository, tradeBotData, atData, tradeData);
+				break;
+
+			case ALICE_DONE:
+			case BOB_DONE:
+				break;
+
+			case ALICE_REFUNDING_A:
+				TradeBot.getInstance().updatePresence(repository, tradeBotData, tradeData);
+				handleAliceRefundingP2shA(repository, tradeBotData, atData, tradeData);
+				break;
+
+			case ALICE_REFUNDED:
+			case BOB_REFUNDED:
+				break;
+		}
+	}
+
+	/**
+	 * Trade-bot is waiting for Bob's AT to deploy.
+	 * <p>
+	 * If AT is deployed, then trade-bot's next step is to wait for MESSAGE from Alice.
+	 */
+	private void handleBobWaitingForAtConfirm(Repository repository, TradeBotData tradeBotData) throws DataException {
+		if (!repository.getATRepository().exists(tradeBotData.getAtAddress())) {
+			if (NTP.getTime() - tradeBotData.getTimestamp() <= MAX_AT_CONFIRMATION_PERIOD)
+				return;
+
+			// We've waited ages for AT to be confirmed into a block but something has gone awry.
+			// After this long we assume transaction loss so give up with trade-bot entry too.
+			tradeBotData.setState(State.BOB_REFUNDED.name());
+			tradeBotData.setStateValue(State.BOB_REFUNDED.value);
+			tradeBotData.setTimestamp(NTP.getTime());
+			// We delete trade-bot entry here instead of saving, hence not using updateTradeBotState()
+			repository.getCrossChainRepository().delete(tradeBotData.getTradePrivateKey());
+			repository.saveChanges();
+
+			LOGGER.info(() -> String.format("AT %s never confirmed. Giving up on trade", tradeBotData.getAtAddress()));
+			TradeBot.notifyStateChange(tradeBotData);
+			return;
+		}
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_WAITING_FOR_MESSAGE,
+				() -> String.format("AT %s confirmed ready. Waiting for trade message", tradeBotData.getAtAddress()));
+	}
+
+	/**
+	 * Trade-bot is waiting for MESSAGE from Alice's trade-bot, containing Alice's trade info.
+	 * <p>
+	 * It's possible Bob has cancelling his trade offer, receiving an automatic QORT refund,
+	 * in which case trade-bot is done with this specific trade and finalizes on refunded state.
+	 * <p>
+	 * Assuming trade is still on offer, trade-bot checks the contents of MESSAGE from Alice's trade-bot.
+	 * <p>
+	 * Details from Alice are used to derive P2SH-A address and this is checked for funding balance.
+	 * <p>
+	 * Assuming P2SH-A has at least expected Litecoin balance,
+	 * Bob's trade-bot constructs a zero-fee, PoW MESSAGE to send to Bob's AT with more trade details.
+	 * <p>
+	 * On processing this MESSAGE, Bob's AT should switch into 'TRADE' mode and only trade with Alice.
+	 * <p>
+	 * Trade-bot's next step is to wait for Alice to redeem the AT, which will allow Bob to
+	 * extract secret-A needed to redeem Alice's P2SH.
+	 * @throws ForeignBlockchainException
+	 */
+	private void handleBobWaitingForMessage(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		// If AT has finished then Bob likely cancelled his trade offer
+		if (atData.getIsFinished()) {
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_REFUNDED,
+					() -> String.format("AT %s cancelled - trading aborted", tradeBotData.getAtAddress()));
+			return;
+		}
+
+		Litecoin litecoin = Litecoin.getInstance();
+
+		String address = tradeBotData.getTradeNativeAddress();
+		List<MessageTransactionData> messageTransactionsData = repository.getMessageRepository().getMessagesByParticipants(null, address, null, null, null);
+
+		for (MessageTransactionData messageTransactionData : messageTransactionsData) {
+			if (messageTransactionData.isText())
+				continue;
+
+			// We're expecting: HASH160(secret-A), Alice's Litecoin pubkeyhash and lockTime-A
+			byte[] messageData = messageTransactionData.getData();
+			LitecoinACCTv2.OfferMessageData offerMessageData = LitecoinACCTv2.extractOfferMessageData(messageData);
+			if (offerMessageData == null)
+				continue;
+
+			byte[] aliceForeignPublicKeyHash = offerMessageData.partnerLitecoinPKH;
+			byte[] hashOfSecretA = offerMessageData.hashOfSecretA;
+			int lockTimeA = (int) offerMessageData.lockTimeA;
+			long messageTimestamp = messageTransactionData.getTimestamp();
+			int refundTimeout = LitecoinACCTv2.calcRefundTimeout(messageTimestamp, lockTimeA);
+
+			// Determine P2SH-A address and confirm funded
+			byte[] redeemScriptA = BitcoinyHTLC.buildScript(aliceForeignPublicKeyHash, lockTimeA, tradeBotData.getTradeForeignPublicKeyHash(), hashOfSecretA);
+			String p2shAddressA = litecoin.deriveP2shAddress(redeemScriptA);
+
+			long feeTimestamp = calcFeeTimestamp(lockTimeA, crossChainTradeData.tradeTimeout);
+			long p2shFee = Litecoin.getInstance().getP2shFee(feeTimestamp);
+			final long minimumAmountA = tradeBotData.getForeignAmount() + p2shFee;
+
+			BitcoinyHTLC.Status htlcStatusA = BitcoinyHTLC.determineHtlcStatus(litecoin.getBlockchainProvider(), p2shAddressA, minimumAmountA);
+
+			switch (htlcStatusA) {
+				case UNFUNDED:
+				case FUNDING_IN_PROGRESS:
+					// There might be another MESSAGE from someone else with an actually funded P2SH-A...
+					continue;
+
+				case REDEEM_IN_PROGRESS:
+				case REDEEMED:
+					// We've already redeemed this?
+					TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_DONE,
+							() -> String.format("P2SH-A %s already spent? Assuming trade complete", p2shAddressA));
+					return;
+
+				case REFUND_IN_PROGRESS:
+				case REFUNDED:
+					// This P2SH-A is burnt, but there might be another MESSAGE from someone else with an actually funded P2SH-A...
+					continue;
+
+				case FUNDED:
+					// Fall-through out of switch...
+					break;
+			}
+
+			// Good to go - send MESSAGE to AT
+
+			String aliceNativeAddress = Crypto.toAddress(messageTransactionData.getCreatorPublicKey());
+
+			// Build outgoing message, padding each part to 32 bytes to make it easier for AT to consume
+			byte[] outgoingMessageData = LitecoinACCTv2.buildTradeMessage(aliceNativeAddress, aliceForeignPublicKeyHash, hashOfSecretA, lockTimeA, refundTimeout);
+			String messageRecipient = tradeBotData.getAtAddress();
+
+			boolean isMessageAlreadySent = repository.getMessageRepository().exists(tradeBotData.getTradeNativePublicKey(), messageRecipient, outgoingMessageData);
+			if (!isMessageAlreadySent) {
+				PrivateKeyAccount sender = new PrivateKeyAccount(repository, tradeBotData.getTradePrivateKey());
+				MessageTransaction outgoingMessageTransaction = MessageTransaction.build(repository, sender, Group.NO_GROUP, messageRecipient, outgoingMessageData, false, false);
+
+				outgoingMessageTransaction.computeNonce();
+				outgoingMessageTransaction.sign(sender);
+
+				// reset repository state to prevent deadlock
+				repository.discardChanges();
+				ValidationResult result = outgoingMessageTransaction.importAsUnconfirmed();
+
+				if (result != ValidationResult.OK) {
+					LOGGER.warn(() -> String.format("Unable to send MESSAGE to AT %s: %s", messageRecipient, result.name()));
+					return;
+				}
+			}
+
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_WAITING_FOR_AT_REDEEM,
+					() -> String.format("Locked AT %s to %s. Waiting for AT redeem", tradeBotData.getAtAddress(), aliceNativeAddress));
+
+			return;
+		}
+	}
+
+	/**
+	 * Trade-bot is waiting for Bob's AT to switch to TRADE mode and lock trade to Alice only.
+	 * <p>
+	 * It's possible that Bob has cancelled his trade offer in the mean time, or that somehow
+	 * this process has taken so long that we've reached P2SH-A's locktime, or that someone else
+	 * has managed to trade with Bob. In any of these cases, trade-bot switches to begin the refunding process.
+	 * <p>
+	 * Assuming Bob's AT is locked to Alice, trade-bot checks AT's state data to make sure it is correct.
+	 * <p>
+	 * If all is well, trade-bot then redeems AT using Alice's secret-A, releasing Bob's QORT to Alice.
+	 * <p>
+	 * In revealing a valid secret-A, Bob can then redeem the LTC funds from P2SH-A.
+	 * <p>
+	 * @throws ForeignBlockchainException
+	 */
+	private void handleAliceWaitingForAtLock(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		if (aliceUnexpectedState(repository, tradeBotData, atData, crossChainTradeData))
+			return;
+
+		Litecoin litecoin = Litecoin.getInstance();
+		int lockTimeA = tradeBotData.getLockTimeA();
+
+		// Refund P2SH-A if we've passed lockTime-A
+		if (NTP.getTime() >= lockTimeA * 1000L) {
+			byte[] redeemScriptA = BitcoinyHTLC.buildScript(tradeBotData.getTradeForeignPublicKeyHash(), lockTimeA, crossChainTradeData.creatorForeignPKH, tradeBotData.getHashOfSecret());
+			String p2shAddressA = litecoin.deriveP2shAddress(redeemScriptA);
+
+			long feeTimestamp = calcFeeTimestamp(lockTimeA, crossChainTradeData.tradeTimeout);
+			long p2shFee = Litecoin.getInstance().getP2shFee(feeTimestamp);
+			long minimumAmountA = crossChainTradeData.expectedForeignAmount + p2shFee;
+
+			BitcoinyHTLC.Status htlcStatusA = BitcoinyHTLC.determineHtlcStatus(litecoin.getBlockchainProvider(), p2shAddressA, minimumAmountA);
+
+			switch (htlcStatusA) {
+				case UNFUNDED:
+				case FUNDING_IN_PROGRESS:
+				case FUNDED:
+					break;
+
+				case REDEEM_IN_PROGRESS:
+				case REDEEMED:
+					// Already redeemed?
+					TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_DONE,
+							() -> String.format("P2SH-A %s already spent? Assuming trade completed", p2shAddressA));
+					return;
+
+				case REFUND_IN_PROGRESS:
+				case REFUNDED:
+					TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDED,
+							() -> String.format("P2SH-A %s already refunded. Trade aborted", p2shAddressA));
+					return;
+
+			}
+
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDING_A,
+					() -> atData.getIsFinished()
+					? String.format("AT %s cancelled. Refunding P2SH-A %s - aborting trade", tradeBotData.getAtAddress(), p2shAddressA)
+					: String.format("LockTime-A reached, refunding P2SH-A %s - aborting trade", p2shAddressA));
+
+			return;
+		}
+
+		// We're waiting for AT to be in TRADE mode
+		if (crossChainTradeData.mode != AcctMode.TRADING)
+			return;
+
+		// AT is in TRADE mode and locked to us as checked by aliceUnexpectedState() above
+
+		// Find our MESSAGE to AT from previous state
+		List<MessageTransactionData> messageTransactionsData = repository.getMessageRepository().getMessagesByParticipants(tradeBotData.getTradeNativePublicKey(),
+				crossChainTradeData.qortalCreatorTradeAddress, null, null, null);
+		if (messageTransactionsData == null || messageTransactionsData.isEmpty()) {
+			LOGGER.warn(() -> String.format("Unable to find our message to trade creator %s?", crossChainTradeData.qortalCreatorTradeAddress));
+			return;
+		}
+
+		long recipientMessageTimestamp = messageTransactionsData.get(0).getTimestamp();
+		int refundTimeout = LitecoinACCTv2.calcRefundTimeout(recipientMessageTimestamp, lockTimeA);
+
+		// Our calculated refundTimeout should match AT's refundTimeout
+		if (refundTimeout != crossChainTradeData.refundTimeout) {
+			LOGGER.debug(() -> String.format("Trade AT refundTimeout '%d' doesn't match our refundTimeout '%d'", crossChainTradeData.refundTimeout, refundTimeout));
+			// We'll eventually refund
+			return;
+		}
+
+		// We're good to redeem AT
+
+		// Send 'redeem' MESSAGE to AT using both secret
+		byte[] secretA = tradeBotData.getSecret();
+		String qortalReceivingAddress = Base58.encode(tradeBotData.getReceivingAccountInfo()); // Actually contains whole address, not just PKH
+		byte[] messageData = LitecoinACCTv2.buildRedeemMessage(secretA, qortalReceivingAddress);
+		String messageRecipient = tradeBotData.getAtAddress();
+
+		boolean isMessageAlreadySent = repository.getMessageRepository().exists(tradeBotData.getTradeNativePublicKey(), messageRecipient, messageData);
+		if (!isMessageAlreadySent) {
+			PrivateKeyAccount sender = new PrivateKeyAccount(repository, tradeBotData.getTradePrivateKey());
+			MessageTransaction messageTransaction = MessageTransaction.build(repository, sender, Group.NO_GROUP, messageRecipient, messageData, false, false);
+
+			messageTransaction.computeNonce();
+			messageTransaction.sign(sender);
+
+			// Reset repository state to prevent deadlock
+			repository.discardChanges();
+			ValidationResult result = messageTransaction.importAsUnconfirmed();
+
+			if (result != ValidationResult.OK) {
+				LOGGER.warn(() -> String.format("Unable to send MESSAGE to AT %s: %s", messageRecipient, result.name()));
+				return;
+			}
+		}
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_DONE,
+				() -> String.format("Redeeming AT %s. Funds should arrive at %s",
+						tradeBotData.getAtAddress(), qortalReceivingAddress));
+	}
+
+	/**
+	 * Trade-bot is waiting for Alice to redeem Bob's AT, thus revealing secret-A which is required to spend the LTC funds from P2SH-A.
+	 * <p>
+	 * It's possible that Bob's AT has reached its trading timeout and automatically refunded QORT back to Bob. In which case,
+	 * trade-bot is done with this specific trade and finalizes in refunded state.
+	 * <p>
+	 * Assuming trade-bot can extract a valid secret-A from Alice's MESSAGE then trade-bot uses that to redeem the LTC funds from P2SH-A
+	 * to Bob's 'foreign'/Litecoin trade legacy-format address, as derived from trade private key.
+	 * <p>
+	 * (This could potentially be 'improved' to send LTC to any address of Bob's choosing by changing the transaction output).
+	 * <p>
+	 * If trade-bot successfully broadcasts the transaction, then this specific trade is done.
+	 * @throws ForeignBlockchainException
+	 */
+	private void handleBobWaitingForAtRedeem(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		// AT should be 'finished' once Alice has redeemed QORT funds
+		if (!atData.getIsFinished())
+			// Not finished yet
+			return;
+
+		// If AT is REFUNDED or CANCELLED then something has gone wrong
+		if (crossChainTradeData.mode == AcctMode.REFUNDED || crossChainTradeData.mode == AcctMode.CANCELLED) {
+			// Alice hasn't redeemed the QORT, so there is no point in trying to redeem the LTC
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_REFUNDED,
+					() -> String.format("AT %s has auto-refunded - trade aborted", tradeBotData.getAtAddress()));
+
+			return;
+		}
+
+		byte[] secretA = LitecoinACCTv2.getInstance().findSecretA(repository, crossChainTradeData);
+		if (secretA == null) {
+			LOGGER.debug(() -> String.format("Unable to find secret-A from redeem message to AT %s?", tradeBotData.getAtAddress()));
+			return;
+		}
+
+		// Use secret-A to redeem P2SH-A
+
+		Litecoin litecoin = Litecoin.getInstance();
+
+		byte[] receivingAccountInfo = tradeBotData.getReceivingAccountInfo();
+		int lockTimeA = crossChainTradeData.lockTimeA;
+		byte[] redeemScriptA = BitcoinyHTLC.buildScript(crossChainTradeData.partnerForeignPKH, lockTimeA, crossChainTradeData.creatorForeignPKH, crossChainTradeData.hashOfSecretA);
+		String p2shAddressA = litecoin.deriveP2shAddress(redeemScriptA);
+
+		// Fee for redeem/refund is subtracted from P2SH-A balance.
+		long feeTimestamp = calcFeeTimestamp(lockTimeA, crossChainTradeData.tradeTimeout);
+		long p2shFee = Litecoin.getInstance().getP2shFee(feeTimestamp);
+		long minimumAmountA = crossChainTradeData.expectedForeignAmount + p2shFee;
+		BitcoinyHTLC.Status htlcStatusA = BitcoinyHTLC.determineHtlcStatus(litecoin.getBlockchainProvider(), p2shAddressA, minimumAmountA);
+
+		switch (htlcStatusA) {
+			case UNFUNDED:
+			case FUNDING_IN_PROGRESS:
+				// P2SH-A suddenly not funded? Our best bet at this point is to hope for AT auto-refund
+				return;
+
+			case REDEEM_IN_PROGRESS:
+			case REDEEMED:
+				// Double-check that we have redeemed P2SH-A...
+				break;
+
+			case REFUND_IN_PROGRESS:
+			case REFUNDED:
+				// Wait for AT to auto-refund
+				return;
+
+			case FUNDED: {
+				Coin redeemAmount = Coin.valueOf(crossChainTradeData.expectedForeignAmount);
+				ECKey redeemKey = ECKey.fromPrivate(tradeBotData.getTradePrivateKey());
+				List<TransactionOutput> fundingOutputs = litecoin.getUnspentOutputs(p2shAddressA);
+
+				Transaction p2shRedeemTransaction = BitcoinyHTLC.buildRedeemTransaction(litecoin.getNetworkParameters(), redeemAmount, redeemKey,
+						fundingOutputs, redeemScriptA, secretA, receivingAccountInfo);
+
+				litecoin.broadcastTransaction(p2shRedeemTransaction);
+				break;
+			}
+		}
+
+		String receivingAddress = litecoin.pkhToAddress(receivingAccountInfo);
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_DONE,
+				() -> String.format("P2SH-A %s redeemed. Funds should arrive at %s", tradeBotData.getAtAddress(), receivingAddress));
+	}
+
+	/**
+	 * Trade-bot is attempting to refund P2SH-A.
+	 * @throws ForeignBlockchainException
+	 */
+	private void handleAliceRefundingP2shA(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		int lockTimeA = tradeBotData.getLockTimeA();
+
+		// We can't refund P2SH-A until lockTime-A has passed
+		if (NTP.getTime() <= lockTimeA * 1000L)
+			return;
+
+		Litecoin litecoin = Litecoin.getInstance();
+
+		// We can't refund P2SH-A until median block time has passed lockTime-A (see BIP113)
+		int medianBlockTime = litecoin.getMedianBlockTime();
+		if (medianBlockTime <= lockTimeA)
+			return;
+
+		byte[] redeemScriptA = BitcoinyHTLC.buildScript(tradeBotData.getTradeForeignPublicKeyHash(), lockTimeA, crossChainTradeData.creatorForeignPKH, tradeBotData.getHashOfSecret());
+		String p2shAddressA = litecoin.deriveP2shAddress(redeemScriptA);
+
+		// Fee for redeem/refund is subtracted from P2SH-A balance.
+		long feeTimestamp = calcFeeTimestamp(lockTimeA, crossChainTradeData.tradeTimeout);
+		long p2shFee = Litecoin.getInstance().getP2shFee(feeTimestamp);
+		long minimumAmountA = crossChainTradeData.expectedForeignAmount + p2shFee;
+		BitcoinyHTLC.Status htlcStatusA = BitcoinyHTLC.determineHtlcStatus(litecoin.getBlockchainProvider(), p2shAddressA, minimumAmountA);
+
+		switch (htlcStatusA) {
+			case UNFUNDED:
+			case FUNDING_IN_PROGRESS:
+				// Still waiting for P2SH-A to be funded...
+				return;
+
+			case REDEEM_IN_PROGRESS:
+			case REDEEMED:
+				// Too late!
+				TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_DONE,
+						() -> String.format("P2SH-A %s already spent!", p2shAddressA));
+				return;
+
+			case REFUND_IN_PROGRESS:
+			case REFUNDED:
+				break;
+
+			case FUNDED:{
+				Coin refundAmount = Coin.valueOf(crossChainTradeData.expectedForeignAmount);
+				ECKey refundKey = ECKey.fromPrivate(tradeBotData.getTradePrivateKey());
+				List<TransactionOutput> fundingOutputs = litecoin.getUnspentOutputs(p2shAddressA);
+
+				// Determine receive address for refund
+				String receiveAddress = litecoin.getUnusedReceiveAddress(tradeBotData.getForeignKey());
+				Address receiving = Address.fromString(litecoin.getNetworkParameters(), receiveAddress);
+
+				Transaction p2shRefundTransaction = BitcoinyHTLC.buildRefundTransaction(litecoin.getNetworkParameters(), refundAmount, refundKey,
+						fundingOutputs, redeemScriptA, lockTimeA, receiving.getHash());
+
+				litecoin.broadcastTransaction(p2shRefundTransaction);
+				break;
+			}
+		}
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDED,
+				() -> String.format("LockTime-A reached. Refunded P2SH-A %s. Trade aborted", p2shAddressA));
+	}
+
+	/**
+	 * Returns true if Alice finds AT unexpectedly cancelled, refunded, redeemed or locked to someone else.
+	 * <p>
+	 * Will automatically update trade-bot state to <tt>ALICE_REFUNDING_A</tt> or <tt>ALICE_DONE</tt> as necessary.
+	 * 
+	 * @throws DataException
+	 * @throws ForeignBlockchainException
+	 */
+	private boolean aliceUnexpectedState(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		// This is OK
+		if (!atData.getIsFinished() && crossChainTradeData.mode == AcctMode.OFFERING)
+			return false;
+
+		boolean isAtLockedToUs = tradeBotData.getTradeNativeAddress().equals(crossChainTradeData.qortalPartnerAddress);
+
+		if (!atData.getIsFinished() && crossChainTradeData.mode == AcctMode.TRADING)
+			if (isAtLockedToUs) {
+				// AT is trading with us - OK
+				return false;
+			} else {
+				TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDING_A,
+						() -> String.format("AT %s trading with someone else: %s. Refunding & aborting trade", tradeBotData.getAtAddress(), crossChainTradeData.qortalPartnerAddress));
+
+				return true;
+			}
+
+		if (atData.getIsFinished() && crossChainTradeData.mode == AcctMode.REDEEMED && isAtLockedToUs) {
+			// We've redeemed already?
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_DONE,
+					() -> String.format("AT %s already redeemed by us. Trade completed", tradeBotData.getAtAddress()));
+		} else {
+			// Any other state is not good, so start defensive refund
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDING_A,
+					() -> String.format("AT %s cancelled/refunded/redeemed by someone else/invalid state. Refunding & aborting trade", tradeBotData.getAtAddress()));
+		}
+
+		return true;
+	}
+
+	private long calcFeeTimestamp(int lockTimeA, int tradeTimeout) {
+		return (lockTimeA - tradeTimeout * 60) * 1000L;
+	}
+
+}

src/main/java/org/qortal/controller/tradebot/LitecoinACCTv3TradeBot.java

@@ -0,0 +1,885 @@
+package org.qortal.controller.tradebot;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.bitcoinj.core.*;
+import org.bitcoinj.script.Script.ScriptType;
+import org.qortal.account.PrivateKeyAccount;
+import org.qortal.account.PublicKeyAccount;
+import org.qortal.api.model.crosschain.TradeBotCreateRequest;
+import org.qortal.asset.Asset;
+import org.qortal.crosschain.*;
+import org.qortal.crypto.Crypto;
+import org.qortal.data.at.ATData;
+import org.qortal.data.crosschain.CrossChainTradeData;
+import org.qortal.data.crosschain.TradeBotData;
+import org.qortal.data.transaction.BaseTransactionData;
+import org.qortal.data.transaction.DeployAtTransactionData;
+import org.qortal.data.transaction.MessageTransactionData;
+import org.qortal.group.Group;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.transaction.DeployAtTransaction;
+import org.qortal.transaction.MessageTransaction;
+import org.qortal.transaction.Transaction.ValidationResult;
+import org.qortal.transform.TransformationException;
+import org.qortal.transform.transaction.DeployAtTransactionTransformer;
+import org.qortal.utils.Base58;
+import org.qortal.utils.NTP;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import static java.util.Arrays.stream;
+import static java.util.stream.Collectors.toMap;
+
+/**
+ * Performing cross-chain trading steps on behalf of user.
+ * <p>
+ * We deal with three different independent state-spaces here:
+ * <ul>
+ * 	<li>Qortal blockchain</li>
+ * 	<li>Foreign blockchain</li>
+ * 	<li>Trade-bot entries</li>
+ * </ul>
+ */
+public class LitecoinACCTv3TradeBot implements AcctTradeBot {
+
+	private static final Logger LOGGER = LogManager.getLogger(LitecoinACCTv3TradeBot.class);
+
+	public enum State implements TradeBot.StateNameAndValueSupplier {
+		BOB_WAITING_FOR_AT_CONFIRM(10, false, false),
+		BOB_WAITING_FOR_MESSAGE(15, true, true),
+		BOB_WAITING_FOR_AT_REDEEM(25, true, true),
+		BOB_DONE(30, false, false),
+		BOB_REFUNDED(35, false, false),
+
+		ALICE_WAITING_FOR_AT_LOCK(85, true, true),
+		ALICE_DONE(95, false, false),
+		ALICE_REFUNDING_A(105, true, true),
+		ALICE_REFUNDED(110, false, false);
+
+		private static final Map<Integer, State> map = stream(State.values()).collect(toMap(state -> state.value, state -> state));
+
+		public final int value;
+		public final boolean requiresAtData;
+		public final boolean requiresTradeData;
+
+		State(int value, boolean requiresAtData, boolean requiresTradeData) {
+			this.value = value;
+			this.requiresAtData = requiresAtData;
+			this.requiresTradeData = requiresTradeData;
+		}
+
+		public static State valueOf(int value) {
+			return map.get(value);
+		}
+
+		@Override
+		public String getState() {
+			return this.name();
+		}
+
+		@Override
+		public int getStateValue() {
+			return this.value;
+		}
+	}
+
+	/** Maximum time Bob waits for his AT creation transaction to be confirmed into a block. (milliseconds) */
+	private static final long MAX_AT_CONFIRMATION_PERIOD = 24 * 60 * 60 * 1000L; // ms
+
+	private static LitecoinACCTv3TradeBot instance;
+
+	private final List<String> endStates = Arrays.asList(State.BOB_DONE, State.BOB_REFUNDED, State.ALICE_DONE, State.ALICE_REFUNDING_A, State.ALICE_REFUNDED).stream()
+			.map(State::name)
+			.collect(Collectors.toUnmodifiableList());
+
+	private LitecoinACCTv3TradeBot() {
+	}
+
+	public static synchronized LitecoinACCTv3TradeBot getInstance() {
+		if (instance == null)
+			instance = new LitecoinACCTv3TradeBot();
+
+		return instance;
+	}
+
+	@Override
+	public List<String> getEndStates() {
+		return this.endStates;
+	}
+
+	/**
+	 * Creates a new trade-bot entry from the "Bob" viewpoint, i.e. OFFERing QORT in exchange for LTC.
+	 * <p>
+	 * Generates:
+	 * <ul>
+	 * 	<li>new 'trade' private key</li>
+	 * </ul>
+	 * Derives:
+	 * <ul>
+	 * 	<li>'native' (as in Qortal) public key, public key hash, address (starting with Q)</li>
+	 * 	<li>'foreign' (as in Litecoin) public key, public key hash</li>
+	 * </ul>
+	 * A Qortal AT is then constructed including the following as constants in the 'data segment':
+	 * <ul>
+	 * 	<li>'native'/Qortal 'trade' address - used as a MESSAGE contact</li>
+	 * 	<li>'foreign'/Litecoin public key hash - used by Alice's P2SH scripts to allow redeem</li>
+	 * 	<li>QORT amount on offer by Bob</li>
+	 * 	<li>LTC amount expected in return by Bob (from Alice)</li>
+	 * 	<li>trading timeout, in case things go wrong and everyone needs to refund</li>
+	 * </ul>
+	 * Returns a DEPLOY_AT transaction that needs to be signed and broadcast to the Qortal network.
+	 * <p>
+	 * Trade-bot will wait for Bob's AT to be deployed before taking next step.
+	 * <p>
+	 * @param repository
+	 * @param tradeBotCreateRequest
+	 * @return raw, unsigned DEPLOY_AT transaction
+	 * @throws DataException
+	 */
+	public byte[] createTrade(Repository repository, TradeBotCreateRequest tradeBotCreateRequest) throws DataException {
+		byte[] tradePrivateKey = TradeBot.generateTradePrivateKey();
+
+		byte[] tradeNativePublicKey = TradeBot.deriveTradeNativePublicKey(tradePrivateKey);
+		byte[] tradeNativePublicKeyHash = Crypto.hash160(tradeNativePublicKey);
+		String tradeNativeAddress = Crypto.toAddress(tradeNativePublicKey);
+
+		byte[] tradeForeignPublicKey = TradeBot.deriveTradeForeignPublicKey(tradePrivateKey);
+		byte[] tradeForeignPublicKeyHash = Crypto.hash160(tradeForeignPublicKey);
+
+		// Convert Litecoin receiving address into public key hash (we only support P2PKH at this time)
+		Address litecoinReceivingAddress;
+		try {
+			litecoinReceivingAddress = Address.fromString(Litecoin.getInstance().getNetworkParameters(), tradeBotCreateRequest.receivingAddress);
+		} catch (AddressFormatException e) {
+			throw new DataException("Unsupported Litecoin receiving address: " + tradeBotCreateRequest.receivingAddress);
+		}
+		if (litecoinReceivingAddress.getOutputScriptType() != ScriptType.P2PKH)
+			throw new DataException("Unsupported Litecoin receiving address: " + tradeBotCreateRequest.receivingAddress);
+
+		byte[] litecoinReceivingAccountInfo = litecoinReceivingAddress.getHash();
+
+		PublicKeyAccount creator = new PublicKeyAccount(repository, tradeBotCreateRequest.creatorPublicKey);
+
+		// Deploy AT
+		long timestamp = NTP.getTime();
+		byte[] reference = creator.getLastReference();
+		long fee = 0L;
+		byte[] signature = null;
+		BaseTransactionData baseTransactionData = new BaseTransactionData(timestamp, Group.NO_GROUP, reference, creator.getPublicKey(), fee, signature);
+
+		String name = "QORT/LTC ACCT";
+		String description = "QORT/LTC cross-chain trade";
+		String aTType = "ACCT";
+		String tags = "ACCT QORT LTC";
+		byte[] creationBytes = LitecoinACCTv3.buildQortalAT(tradeNativeAddress, tradeForeignPublicKeyHash, tradeBotCreateRequest.qortAmount,
+				tradeBotCreateRequest.foreignAmount, tradeBotCreateRequest.tradeTimeout);
+		long amount = tradeBotCreateRequest.fundingQortAmount;
+
+		DeployAtTransactionData deployAtTransactionData = new DeployAtTransactionData(baseTransactionData, name, description, aTType, tags, creationBytes, amount, Asset.QORT);
+
+		DeployAtTransaction deployAtTransaction = new DeployAtTransaction(repository, deployAtTransactionData);
+		fee = deployAtTransaction.calcRecommendedFee();
+		deployAtTransactionData.setFee(fee);
+
+		DeployAtTransaction.ensureATAddress(deployAtTransactionData);
+		String atAddress = deployAtTransactionData.getAtAddress();
+
+		TradeBotData tradeBotData =  new TradeBotData(tradePrivateKey, LitecoinACCTv3.NAME,
+				State.BOB_WAITING_FOR_AT_CONFIRM.name(), State.BOB_WAITING_FOR_AT_CONFIRM.value,
+				creator.getAddress(), atAddress, timestamp, tradeBotCreateRequest.qortAmount,
+				tradeNativePublicKey, tradeNativePublicKeyHash, tradeNativeAddress,
+				null, null,
+				SupportedBlockchain.LITECOIN.name(),
+				tradeForeignPublicKey, tradeForeignPublicKeyHash,
+				tradeBotCreateRequest.foreignAmount, null, null, null, litecoinReceivingAccountInfo);
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, () -> String.format("Built AT %s. Waiting for deployment", atAddress));
+
+		// Attempt to backup the trade bot data
+		TradeBot.backupTradeBotData(repository, null);
+
+		// Return to user for signing and broadcast as we don't have their Qortal private key
+		try {
+			return DeployAtTransactionTransformer.toBytes(deployAtTransactionData);
+		} catch (TransformationException e) {
+			throw new DataException("Failed to transform DEPLOY_AT transaction?", e);
+		}
+	}
+
+	/**
+	 * Creates a trade-bot entry from the 'Alice' viewpoint, i.e. matching LTC to an existing offer.
+	 * <p>
+	 * Requires a chosen trade offer from Bob, passed by <tt>crossChainTradeData</tt>
+	 * and access to a Litecoin wallet via <tt>xprv58</tt>.
+	 * <p>
+	 * The <tt>crossChainTradeData</tt> contains the current trade offer state
+	 * as extracted from the AT's data segment.
+	 * <p>
+	 * Access to a funded wallet is via a Litecoin BIP32 hierarchical deterministic key,
+	 * passed via <tt>xprv58</tt>.
+	 * <b>This key will be stored in your node's database</b>
+	 * to allow trade-bot to create/fund the necessary P2SH transactions!
+	 * However, due to the nature of BIP32 keys, it is possible to give the trade-bot
+	 * only a subset of wallet access (see BIP32 for more details).
+	 * <p>
+	 * As an example, the xprv58 can be extract from a <i>legacy, password-less</i>
+	 * Electrum wallet by going to the console tab and entering:<br>
+	 * <tt>wallet.keystore.xprv</tt><br>
+	 * which should result in a base58 string starting with either 'xprv' (for Litecoin main-net)
+	 * or 'tprv' for (Litecoin test-net).
+	 * <p>
+	 * It is envisaged that the value in <tt>xprv58</tt> will actually come from a Qortal-UI-managed wallet.
+	 * <p>
+	 * If sufficient funds are available, <b>this method will actually fund the P2SH-A</b>
+	 * with the Litecoin amount expected by 'Bob'.
+	 * <p>
+	 * If the Litecoin transaction is successfully broadcast to the network then
+	 * we also send a MESSAGE to Bob's trade-bot to let them know.
+	 * <p>
+	 * The trade-bot entry is saved to the repository and the cross-chain trading process commences.
+	 * <p>
+	 * @param repository
+	 * @param crossChainTradeData chosen trade OFFER that Alice wants to match
+	 * @param xprv58 funded wallet xprv in base58
+	 * @return true if P2SH-A funding transaction successfully broadcast to Litecoin network, false otherwise
+	 * @throws DataException
+	 */
+	public ResponseResult startResponse(Repository repository, ATData atData, ACCT acct, CrossChainTradeData crossChainTradeData, String xprv58, String receivingAddress) throws DataException {
+		byte[] tradePrivateKey = TradeBot.generateTradePrivateKey();
+		byte[] secretA = TradeBot.generateSecret();
+		byte[] hashOfSecretA = Crypto.hash160(secretA);
+
+		byte[] tradeNativePublicKey = TradeBot.deriveTradeNativePublicKey(tradePrivateKey);
+		byte[] tradeNativePublicKeyHash = Crypto.hash160(tradeNativePublicKey);
+		String tradeNativeAddress = Crypto.toAddress(tradeNativePublicKey);
+
+		byte[] tradeForeignPublicKey = TradeBot.deriveTradeForeignPublicKey(tradePrivateKey);
+		byte[] tradeForeignPublicKeyHash = Crypto.hash160(tradeForeignPublicKey);
+		byte[] receivingPublicKeyHash = Base58.decode(receivingAddress); // Actually the whole address, not just PKH
+
+		// We need to generate lockTime-A: add tradeTimeout to now
+		long now = NTP.getTime();
+		int lockTimeA = crossChainTradeData.tradeTimeout * 60 + (int) (now / 1000L);
+
+		TradeBotData tradeBotData =  new TradeBotData(tradePrivateKey, LitecoinACCTv3.NAME,
+				State.ALICE_WAITING_FOR_AT_LOCK.name(), State.ALICE_WAITING_FOR_AT_LOCK.value,
+				receivingAddress, crossChainTradeData.qortalAtAddress, now, crossChainTradeData.qortAmount,
+				tradeNativePublicKey, tradeNativePublicKeyHash, tradeNativeAddress,
+				secretA, hashOfSecretA,
+				SupportedBlockchain.LITECOIN.name(),
+				tradeForeignPublicKey, tradeForeignPublicKeyHash,
+				crossChainTradeData.expectedForeignAmount, xprv58, null, lockTimeA, receivingPublicKeyHash);
+
+		// Attempt to backup the trade bot data
+		// Include tradeBotData as an additional parameter, since it's not in the repository yet
+		TradeBot.backupTradeBotData(repository, Arrays.asList(tradeBotData));
+
+		// Check we have enough funds via xprv58 to fund P2SH to cover expectedForeignAmount
+		long p2shFee;
+		try {
+			p2shFee = Litecoin.getInstance().getP2shFee(now);
+		} catch (ForeignBlockchainException e) {
+			LOGGER.debug("Couldn't estimate Litecoin fees?");
+			return ResponseResult.NETWORK_ISSUE;
+		}
+
+		// Fee for redeem/refund is subtracted from P2SH-A balance.
+		// Do not include fee for funding transaction as this is covered by buildSpend()
+		long amountA = crossChainTradeData.expectedForeignAmount + p2shFee /*redeeming/refunding P2SH-A*/;
+
+		// P2SH-A to be funded
+		byte[] redeemScriptBytes = BitcoinyHTLC.buildScript(tradeForeignPublicKeyHash, lockTimeA, crossChainTradeData.creatorForeignPKH, hashOfSecretA);
+		String p2shAddress = Litecoin.getInstance().deriveP2shAddress(redeemScriptBytes);
+
+		// Build transaction for funding P2SH-A
+		Transaction p2shFundingTransaction = Litecoin.getInstance().buildSpend(tradeBotData.getForeignKey(), p2shAddress, amountA);
+		if (p2shFundingTransaction == null) {
+			LOGGER.debug("Unable to build P2SH-A funding transaction - lack of funds?");
+			return ResponseResult.BALANCE_ISSUE;
+		}
+
+		try {
+			Litecoin.getInstance().broadcastTransaction(p2shFundingTransaction);
+		} catch (ForeignBlockchainException e) {
+			// We couldn't fund P2SH-A at this time
+			LOGGER.debug("Couldn't broadcast P2SH-A funding transaction?");
+			return ResponseResult.NETWORK_ISSUE;
+		}
+
+		// Attempt to send MESSAGE to Bob's Qortal trade address
+		byte[] messageData = LitecoinACCTv3.buildOfferMessage(tradeBotData.getTradeForeignPublicKeyHash(), tradeBotData.getHashOfSecret(), tradeBotData.getLockTimeA());
+		String messageRecipient = crossChainTradeData.qortalCreatorTradeAddress;
+
+		boolean isMessageAlreadySent = repository.getMessageRepository().exists(tradeBotData.getTradeNativePublicKey(), messageRecipient, messageData);
+		if (!isMessageAlreadySent) {
+			PrivateKeyAccount sender = new PrivateKeyAccount(repository, tradeBotData.getTradePrivateKey());
+			MessageTransaction messageTransaction = MessageTransaction.build(repository, sender, Group.NO_GROUP, messageRecipient, messageData, false, false);
+
+			messageTransaction.computeNonce();
+			messageTransaction.sign(sender);
+
+			// reset repository state to prevent deadlock
+			repository.discardChanges();
+			ValidationResult result = messageTransaction.importAsUnconfirmed();
+
+			if (result != ValidationResult.OK) {
+				LOGGER.warn(() -> String.format("Unable to send MESSAGE to Bob's trade-bot %s: %s", messageRecipient, result.name()));
+				return ResponseResult.NETWORK_ISSUE;
+			}
+		}
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, () -> String.format("Funding P2SH-A %s. Messaged Bob. Waiting for AT-lock", p2shAddress));
+
+		return ResponseResult.OK;
+	}
+
+	@Override
+	public boolean canDelete(Repository repository, TradeBotData tradeBotData) throws DataException {
+		State tradeBotState = State.valueOf(tradeBotData.getStateValue());
+		if (tradeBotState == null)
+			return true;
+
+		// If the AT doesn't exist then we might as well let the user tidy up
+		if (!repository.getATRepository().exists(tradeBotData.getAtAddress()))
+			return true;
+
+		switch (tradeBotState) {
+			case BOB_WAITING_FOR_AT_CONFIRM:
+			case ALICE_DONE:
+			case BOB_DONE:
+			case ALICE_REFUNDED:
+			case BOB_REFUNDED:
+			case ALICE_REFUNDING_A:
+				return true;
+
+			default:
+				return false;
+		}
+	}
+
+	@Override
+	public void progress(Repository repository, TradeBotData tradeBotData) throws DataException, ForeignBlockchainException {
+		State tradeBotState = State.valueOf(tradeBotData.getStateValue());
+		if (tradeBotState == null) {
+			LOGGER.info(() -> String.format("Trade-bot entry for AT %s has invalid state?", tradeBotData.getAtAddress()));
+			return;
+		}
+
+		ATData atData = null;
+		CrossChainTradeData tradeData = null;
+
+		if (tradeBotState.requiresAtData) {
+			// Attempt to fetch AT data
+			atData = repository.getATRepository().fromATAddress(tradeBotData.getAtAddress());
+			if (atData == null) {
+				LOGGER.debug(() -> String.format("Unable to fetch trade AT %s from repository", tradeBotData.getAtAddress()));
+				return;
+			}
+
+			if (tradeBotState.requiresTradeData) {
+				tradeData = LitecoinACCTv3.getInstance().populateTradeData(repository, atData);
+				if (tradeData == null) {
+					LOGGER.warn(() -> String.format("Unable to fetch ACCT trade data for AT %s from repository", tradeBotData.getAtAddress()));
+					return;
+				}
+			}
+		}
+
+		switch (tradeBotState) {
+			case BOB_WAITING_FOR_AT_CONFIRM:
+				handleBobWaitingForAtConfirm(repository, tradeBotData);
+				break;
+
+			case BOB_WAITING_FOR_MESSAGE:
+				TradeBot.getInstance().updatePresence(repository, tradeBotData, tradeData);
+				handleBobWaitingForMessage(repository, tradeBotData, atData, tradeData);
+				break;
+
+			case ALICE_WAITING_FOR_AT_LOCK:
+				TradeBot.getInstance().updatePresence(repository, tradeBotData, tradeData);
+				handleAliceWaitingForAtLock(repository, tradeBotData, atData, tradeData);
+				break;
+
+			case BOB_WAITING_FOR_AT_REDEEM:
+				TradeBot.getInstance().updatePresence(repository, tradeBotData, tradeData);
+				handleBobWaitingForAtRedeem(repository, tradeBotData, atData, tradeData);
+				break;
+
+			case ALICE_DONE:
+			case BOB_DONE:
+				break;
+
+			case ALICE_REFUNDING_A:
+				TradeBot.getInstance().updatePresence(repository, tradeBotData, tradeData);
+				handleAliceRefundingP2shA(repository, tradeBotData, atData, tradeData);
+				break;
+
+			case ALICE_REFUNDED:
+			case BOB_REFUNDED:
+				break;
+		}
+	}
+
+	/**
+	 * Trade-bot is waiting for Bob's AT to deploy.
+	 * <p>
+	 * If AT is deployed, then trade-bot's next step is to wait for MESSAGE from Alice.
+	 */
+	private void handleBobWaitingForAtConfirm(Repository repository, TradeBotData tradeBotData) throws DataException {
+		if (!repository.getATRepository().exists(tradeBotData.getAtAddress())) {
+			if (NTP.getTime() - tradeBotData.getTimestamp() <= MAX_AT_CONFIRMATION_PERIOD)
+				return;
+
+			// We've waited ages for AT to be confirmed into a block but something has gone awry.
+			// After this long we assume transaction loss so give up with trade-bot entry too.
+			tradeBotData.setState(State.BOB_REFUNDED.name());
+			tradeBotData.setStateValue(State.BOB_REFUNDED.value);
+			tradeBotData.setTimestamp(NTP.getTime());
+			// We delete trade-bot entry here instead of saving, hence not using updateTradeBotState()
+			repository.getCrossChainRepository().delete(tradeBotData.getTradePrivateKey());
+			repository.saveChanges();
+
+			LOGGER.info(() -> String.format("AT %s never confirmed. Giving up on trade", tradeBotData.getAtAddress()));
+			TradeBot.notifyStateChange(tradeBotData);
+			return;
+		}
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_WAITING_FOR_MESSAGE,
+				() -> String.format("AT %s confirmed ready. Waiting for trade message", tradeBotData.getAtAddress()));
+	}
+
+	/**
+	 * Trade-bot is waiting for MESSAGE from Alice's trade-bot, containing Alice's trade info.
+	 * <p>
+	 * It's possible Bob has cancelling his trade offer, receiving an automatic QORT refund,
+	 * in which case trade-bot is done with this specific trade and finalizes on refunded state.
+	 * <p>
+	 * Assuming trade is still on offer, trade-bot checks the contents of MESSAGE from Alice's trade-bot.
+	 * <p>
+	 * Details from Alice are used to derive P2SH-A address and this is checked for funding balance.
+	 * <p>
+	 * Assuming P2SH-A has at least expected Litecoin balance,
+	 * Bob's trade-bot constructs a zero-fee, PoW MESSAGE to send to Bob's AT with more trade details.
+	 * <p>
+	 * On processing this MESSAGE, Bob's AT should switch into 'TRADE' mode and only trade with Alice.
+	 * <p>
+	 * Trade-bot's next step is to wait for Alice to redeem the AT, which will allow Bob to
+	 * extract secret-A needed to redeem Alice's P2SH.
+	 * @throws ForeignBlockchainException
+	 */
+	private void handleBobWaitingForMessage(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		// If AT has finished then Bob likely cancelled his trade offer
+		if (atData.getIsFinished()) {
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_REFUNDED,
+					() -> String.format("AT %s cancelled - trading aborted", tradeBotData.getAtAddress()));
+			return;
+		}
+
+		Litecoin litecoin = Litecoin.getInstance();
+
+		String address = tradeBotData.getTradeNativeAddress();
+		List<MessageTransactionData> messageTransactionsData = repository.getMessageRepository().getMessagesByParticipants(null, address, null, null, null);
+
+		for (MessageTransactionData messageTransactionData : messageTransactionsData) {
+			if (messageTransactionData.isText())
+				continue;
+
+			// We're expecting: HASH160(secret-A), Alice's Litecoin pubkeyhash and lockTime-A
+			byte[] messageData = messageTransactionData.getData();
+			LitecoinACCTv3.OfferMessageData offerMessageData = LitecoinACCTv3.extractOfferMessageData(messageData);
+			if (offerMessageData == null)
+				continue;
+
+			byte[] aliceForeignPublicKeyHash = offerMessageData.partnerLitecoinPKH;
+			byte[] hashOfSecretA = offerMessageData.hashOfSecretA;
+			int lockTimeA = (int) offerMessageData.lockTimeA;
+			long messageTimestamp = messageTransactionData.getTimestamp();
+			int refundTimeout = LitecoinACCTv3.calcRefundTimeout(messageTimestamp, lockTimeA);
+
+			// Determine P2SH-A address and confirm funded
+			byte[] redeemScriptA = BitcoinyHTLC.buildScript(aliceForeignPublicKeyHash, lockTimeA, tradeBotData.getTradeForeignPublicKeyHash(), hashOfSecretA);
+			String p2shAddressA = litecoin.deriveP2shAddress(redeemScriptA);
+
+			long feeTimestamp = calcFeeTimestamp(lockTimeA, crossChainTradeData.tradeTimeout);
+			long p2shFee = Litecoin.getInstance().getP2shFee(feeTimestamp);
+			final long minimumAmountA = tradeBotData.getForeignAmount() + p2shFee;
+
+			BitcoinyHTLC.Status htlcStatusA = BitcoinyHTLC.determineHtlcStatus(litecoin.getBlockchainProvider(), p2shAddressA, minimumAmountA);
+
+			switch (htlcStatusA) {
+				case UNFUNDED:
+				case FUNDING_IN_PROGRESS:
+					// There might be another MESSAGE from someone else with an actually funded P2SH-A...
+					continue;
+
+				case REDEEM_IN_PROGRESS:
+				case REDEEMED:
+					// We've already redeemed this?
+					TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_DONE,
+							() -> String.format("P2SH-A %s already spent? Assuming trade complete", p2shAddressA));
+					return;
+
+				case REFUND_IN_PROGRESS:
+				case REFUNDED:
+					// This P2SH-A is burnt, but there might be another MESSAGE from someone else with an actually funded P2SH-A...
+					continue;
+
+				case FUNDED:
+					// Fall-through out of switch...
+					break;
+			}
+
+			// Good to go - send MESSAGE to AT
+
+			String aliceNativeAddress = Crypto.toAddress(messageTransactionData.getCreatorPublicKey());
+
+			// Build outgoing message, padding each part to 32 bytes to make it easier for AT to consume
+			byte[] outgoingMessageData = LitecoinACCTv3.buildTradeMessage(aliceNativeAddress, aliceForeignPublicKeyHash, hashOfSecretA, lockTimeA, refundTimeout);
+			String messageRecipient = tradeBotData.getAtAddress();
+
+			boolean isMessageAlreadySent = repository.getMessageRepository().exists(tradeBotData.getTradeNativePublicKey(), messageRecipient, outgoingMessageData);
+			if (!isMessageAlreadySent) {
+				PrivateKeyAccount sender = new PrivateKeyAccount(repository, tradeBotData.getTradePrivateKey());
+				MessageTransaction outgoingMessageTransaction = MessageTransaction.build(repository, sender, Group.NO_GROUP, messageRecipient, outgoingMessageData, false, false);
+
+				outgoingMessageTransaction.computeNonce();
+				outgoingMessageTransaction.sign(sender);
+
+				// reset repository state to prevent deadlock
+				repository.discardChanges();
+				ValidationResult result = outgoingMessageTransaction.importAsUnconfirmed();
+
+				if (result != ValidationResult.OK) {
+					LOGGER.warn(() -> String.format("Unable to send MESSAGE to AT %s: %s", messageRecipient, result.name()));
+					return;
+				}
+			}
+
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_WAITING_FOR_AT_REDEEM,
+					() -> String.format("Locked AT %s to %s. Waiting for AT redeem", tradeBotData.getAtAddress(), aliceNativeAddress));
+
+			return;
+		}
+	}
+
+	/**
+	 * Trade-bot is waiting for Bob's AT to switch to TRADE mode and lock trade to Alice only.
+	 * <p>
+	 * It's possible that Bob has cancelled his trade offer in the mean time, or that somehow
+	 * this process has taken so long that we've reached P2SH-A's locktime, or that someone else
+	 * has managed to trade with Bob. In any of these cases, trade-bot switches to begin the refunding process.
+	 * <p>
+	 * Assuming Bob's AT is locked to Alice, trade-bot checks AT's state data to make sure it is correct.
+	 * <p>
+	 * If all is well, trade-bot then redeems AT using Alice's secret-A, releasing Bob's QORT to Alice.
+	 * <p>
+	 * In revealing a valid secret-A, Bob can then redeem the LTC funds from P2SH-A.
+	 * <p>
+	 * @throws ForeignBlockchainException
+	 */
+	private void handleAliceWaitingForAtLock(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		if (aliceUnexpectedState(repository, tradeBotData, atData, crossChainTradeData))
+			return;
+
+		Litecoin litecoin = Litecoin.getInstance();
+		int lockTimeA = tradeBotData.getLockTimeA();
+
+		// Refund P2SH-A if we've passed lockTime-A
+		if (NTP.getTime() >= lockTimeA * 1000L) {
+			byte[] redeemScriptA = BitcoinyHTLC.buildScript(tradeBotData.getTradeForeignPublicKeyHash(), lockTimeA, crossChainTradeData.creatorForeignPKH, tradeBotData.getHashOfSecret());
+			String p2shAddressA = litecoin.deriveP2shAddress(redeemScriptA);
+
+			long feeTimestamp = calcFeeTimestamp(lockTimeA, crossChainTradeData.tradeTimeout);
+			long p2shFee = Litecoin.getInstance().getP2shFee(feeTimestamp);
+			long minimumAmountA = crossChainTradeData.expectedForeignAmount + p2shFee;
+
+			BitcoinyHTLC.Status htlcStatusA = BitcoinyHTLC.determineHtlcStatus(litecoin.getBlockchainProvider(), p2shAddressA, minimumAmountA);
+
+			switch (htlcStatusA) {
+				case UNFUNDED:
+				case FUNDING_IN_PROGRESS:
+				case FUNDED:
+					break;
+
+				case REDEEM_IN_PROGRESS:
+				case REDEEMED:
+					// Already redeemed?
+					TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_DONE,
+							() -> String.format("P2SH-A %s already spent? Assuming trade completed", p2shAddressA));
+					return;
+
+				case REFUND_IN_PROGRESS:
+				case REFUNDED:
+					TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDED,
+							() -> String.format("P2SH-A %s already refunded. Trade aborted", p2shAddressA));
+					return;
+
+			}
+
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDING_A,
+					() -> atData.getIsFinished()
+					? String.format("AT %s cancelled. Refunding P2SH-A %s - aborting trade", tradeBotData.getAtAddress(), p2shAddressA)
+					: String.format("LockTime-A reached, refunding P2SH-A %s - aborting trade", p2shAddressA));
+
+			return;
+		}
+
+		// We're waiting for AT to be in TRADE mode
+		if (crossChainTradeData.mode != AcctMode.TRADING)
+			return;
+
+		// AT is in TRADE mode and locked to us as checked by aliceUnexpectedState() above
+
+		// Find our MESSAGE to AT from previous state
+		List<MessageTransactionData> messageTransactionsData = repository.getMessageRepository().getMessagesByParticipants(tradeBotData.getTradeNativePublicKey(),
+				crossChainTradeData.qortalCreatorTradeAddress, null, null, null);
+		if (messageTransactionsData == null || messageTransactionsData.isEmpty()) {
+			LOGGER.warn(() -> String.format("Unable to find our message to trade creator %s?", crossChainTradeData.qortalCreatorTradeAddress));
+			return;
+		}
+
+		long recipientMessageTimestamp = messageTransactionsData.get(0).getTimestamp();
+		int refundTimeout = LitecoinACCTv3.calcRefundTimeout(recipientMessageTimestamp, lockTimeA);
+
+		// Our calculated refundTimeout should match AT's refundTimeout
+		if (refundTimeout != crossChainTradeData.refundTimeout) {
+			LOGGER.debug(() -> String.format("Trade AT refundTimeout '%d' doesn't match our refundTimeout '%d'", crossChainTradeData.refundTimeout, refundTimeout));
+			// We'll eventually refund
+			return;
+		}
+
+		// We're good to redeem AT
+
+		// Send 'redeem' MESSAGE to AT using both secret
+		byte[] secretA = tradeBotData.getSecret();
+		String qortalReceivingAddress = Base58.encode(tradeBotData.getReceivingAccountInfo()); // Actually contains whole address, not just PKH
+		byte[] messageData = LitecoinACCTv3.buildRedeemMessage(secretA, qortalReceivingAddress);
+		String messageRecipient = tradeBotData.getAtAddress();
+
+		boolean isMessageAlreadySent = repository.getMessageRepository().exists(tradeBotData.getTradeNativePublicKey(), messageRecipient, messageData);
+		if (!isMessageAlreadySent) {
+			PrivateKeyAccount sender = new PrivateKeyAccount(repository, tradeBotData.getTradePrivateKey());
+			MessageTransaction messageTransaction = MessageTransaction.build(repository, sender, Group.NO_GROUP, messageRecipient, messageData, false, false);
+
+			messageTransaction.computeNonce();
+			messageTransaction.sign(sender);
+
+			// Reset repository state to prevent deadlock
+			repository.discardChanges();
+			ValidationResult result = messageTransaction.importAsUnconfirmed();
+
+			if (result != ValidationResult.OK) {
+				LOGGER.warn(() -> String.format("Unable to send MESSAGE to AT %s: %s", messageRecipient, result.name()));
+				return;
+			}
+		}
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_DONE,
+				() -> String.format("Redeeming AT %s. Funds should arrive at %s",
+						tradeBotData.getAtAddress(), qortalReceivingAddress));
+	}
+
+	/**
+	 * Trade-bot is waiting for Alice to redeem Bob's AT, thus revealing secret-A which is required to spend the LTC funds from P2SH-A.
+	 * <p>
+	 * It's possible that Bob's AT has reached its trading timeout and automatically refunded QORT back to Bob. In which case,
+	 * trade-bot is done with this specific trade and finalizes in refunded state.
+	 * <p>
+	 * Assuming trade-bot can extract a valid secret-A from Alice's MESSAGE then trade-bot uses that to redeem the LTC funds from P2SH-A
+	 * to Bob's 'foreign'/Litecoin trade legacy-format address, as derived from trade private key.
+	 * <p>
+	 * (This could potentially be 'improved' to send LTC to any address of Bob's choosing by changing the transaction output).
+	 * <p>
+	 * If trade-bot successfully broadcasts the transaction, then this specific trade is done.
+	 * @throws ForeignBlockchainException
+	 */
+	private void handleBobWaitingForAtRedeem(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		// AT should be 'finished' once Alice has redeemed QORT funds
+		if (!atData.getIsFinished())
+			// Not finished yet
+			return;
+
+		// If AT is REFUNDED or CANCELLED then something has gone wrong
+		if (crossChainTradeData.mode == AcctMode.REFUNDED || crossChainTradeData.mode == AcctMode.CANCELLED) {
+			// Alice hasn't redeemed the QORT, so there is no point in trying to redeem the LTC
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_REFUNDED,
+					() -> String.format("AT %s has auto-refunded - trade aborted", tradeBotData.getAtAddress()));
+
+			return;
+		}
+
+		byte[] secretA = LitecoinACCTv3.getInstance().findSecretA(repository, crossChainTradeData);
+		if (secretA == null) {
+			LOGGER.debug(() -> String.format("Unable to find secret-A from redeem message to AT %s?", tradeBotData.getAtAddress()));
+			return;
+		}
+
+		// Use secret-A to redeem P2SH-A
+
+		Litecoin litecoin = Litecoin.getInstance();
+
+		byte[] receivingAccountInfo = tradeBotData.getReceivingAccountInfo();
+		int lockTimeA = crossChainTradeData.lockTimeA;
+		byte[] redeemScriptA = BitcoinyHTLC.buildScript(crossChainTradeData.partnerForeignPKH, lockTimeA, crossChainTradeData.creatorForeignPKH, crossChainTradeData.hashOfSecretA);
+		String p2shAddressA = litecoin.deriveP2shAddress(redeemScriptA);
+
+		// Fee for redeem/refund is subtracted from P2SH-A balance.
+		long feeTimestamp = calcFeeTimestamp(lockTimeA, crossChainTradeData.tradeTimeout);
+		long p2shFee = Litecoin.getInstance().getP2shFee(feeTimestamp);
+		long minimumAmountA = crossChainTradeData.expectedForeignAmount + p2shFee;
+		BitcoinyHTLC.Status htlcStatusA = BitcoinyHTLC.determineHtlcStatus(litecoin.getBlockchainProvider(), p2shAddressA, minimumAmountA);
+
+		switch (htlcStatusA) {
+			case UNFUNDED:
+			case FUNDING_IN_PROGRESS:
+				// P2SH-A suddenly not funded? Our best bet at this point is to hope for AT auto-refund
+				return;
+
+			case REDEEM_IN_PROGRESS:
+			case REDEEMED:
+				// Double-check that we have redeemed P2SH-A...
+				break;
+
+			case REFUND_IN_PROGRESS:
+			case REFUNDED:
+				// Wait for AT to auto-refund
+				return;
+
+			case FUNDED: {
+				Coin redeemAmount = Coin.valueOf(crossChainTradeData.expectedForeignAmount);
+				ECKey redeemKey = ECKey.fromPrivate(tradeBotData.getTradePrivateKey());
+				List<TransactionOutput> fundingOutputs = litecoin.getUnspentOutputs(p2shAddressA);
+
+				Transaction p2shRedeemTransaction = BitcoinyHTLC.buildRedeemTransaction(litecoin.getNetworkParameters(), redeemAmount, redeemKey,
+						fundingOutputs, redeemScriptA, secretA, receivingAccountInfo);
+
+				litecoin.broadcastTransaction(p2shRedeemTransaction);
+				break;
+			}
+		}
+
+		String receivingAddress = litecoin.pkhToAddress(receivingAccountInfo);
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, State.BOB_DONE,
+				() -> String.format("P2SH-A %s redeemed. Funds should arrive at %s", tradeBotData.getAtAddress(), receivingAddress));
+	}
+
+	/**
+	 * Trade-bot is attempting to refund P2SH-A.
+	 * @throws ForeignBlockchainException
+	 */
+	private void handleAliceRefundingP2shA(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		int lockTimeA = tradeBotData.getLockTimeA();
+
+		// We can't refund P2SH-A until lockTime-A has passed
+		if (NTP.getTime() <= lockTimeA * 1000L)
+			return;
+
+		Litecoin litecoin = Litecoin.getInstance();
+
+		// We can't refund P2SH-A until median block time has passed lockTime-A (see BIP113)
+		int medianBlockTime = litecoin.getMedianBlockTime();
+		if (medianBlockTime <= lockTimeA)
+			return;
+
+		byte[] redeemScriptA = BitcoinyHTLC.buildScript(tradeBotData.getTradeForeignPublicKeyHash(), lockTimeA, crossChainTradeData.creatorForeignPKH, tradeBotData.getHashOfSecret());
+		String p2shAddressA = litecoin.deriveP2shAddress(redeemScriptA);
+
+		// Fee for redeem/refund is subtracted from P2SH-A balance.
+		long feeTimestamp = calcFeeTimestamp(lockTimeA, crossChainTradeData.tradeTimeout);
+		long p2shFee = Litecoin.getInstance().getP2shFee(feeTimestamp);
+		long minimumAmountA = crossChainTradeData.expectedForeignAmount + p2shFee;
+		BitcoinyHTLC.Status htlcStatusA = BitcoinyHTLC.determineHtlcStatus(litecoin.getBlockchainProvider(), p2shAddressA, minimumAmountA);
+
+		switch (htlcStatusA) {
+			case UNFUNDED:
+			case FUNDING_IN_PROGRESS:
+				// Still waiting for P2SH-A to be funded...
+				return;
+
+			case REDEEM_IN_PROGRESS:
+			case REDEEMED:
+				// Too late!
+				TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_DONE,
+						() -> String.format("P2SH-A %s already spent!", p2shAddressA));
+				return;
+
+			case REFUND_IN_PROGRESS:
+			case REFUNDED:
+				break;
+
+			case FUNDED:{
+				Coin refundAmount = Coin.valueOf(crossChainTradeData.expectedForeignAmount);
+				ECKey refundKey = ECKey.fromPrivate(tradeBotData.getTradePrivateKey());
+				List<TransactionOutput> fundingOutputs = litecoin.getUnspentOutputs(p2shAddressA);
+
+				// Determine receive address for refund
+				String receiveAddress = litecoin.getUnusedReceiveAddress(tradeBotData.getForeignKey());
+				Address receiving = Address.fromString(litecoin.getNetworkParameters(), receiveAddress);
+
+				Transaction p2shRefundTransaction = BitcoinyHTLC.buildRefundTransaction(litecoin.getNetworkParameters(), refundAmount, refundKey,
+						fundingOutputs, redeemScriptA, lockTimeA, receiving.getHash());
+
+				litecoin.broadcastTransaction(p2shRefundTransaction);
+				break;
+			}
+		}
+
+		TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDED,
+				() -> String.format("LockTime-A reached. Refunded P2SH-A %s. Trade aborted", p2shAddressA));
+	}
+
+	/**
+	 * Returns true if Alice finds AT unexpectedly cancelled, refunded, redeemed or locked to someone else.
+	 * <p>
+	 * Will automatically update trade-bot state to <tt>ALICE_REFUNDING_A</tt> or <tt>ALICE_DONE</tt> as necessary.
+	 * 
+	 * @throws DataException
+	 * @throws ForeignBlockchainException
+	 */
+	private boolean aliceUnexpectedState(Repository repository, TradeBotData tradeBotData,
+			ATData atData, CrossChainTradeData crossChainTradeData) throws DataException, ForeignBlockchainException {
+		// This is OK
+		if (!atData.getIsFinished() && crossChainTradeData.mode == AcctMode.OFFERING)
+			return false;
+
+		boolean isAtLockedToUs = tradeBotData.getTradeNativeAddress().equals(crossChainTradeData.qortalPartnerAddress);
+
+		if (!atData.getIsFinished() && crossChainTradeData.mode == AcctMode.TRADING)
+			if (isAtLockedToUs) {
+				// AT is trading with us - OK
+				return false;
+			} else {
+				TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDING_A,
+						() -> String.format("AT %s trading with someone else: %s. Refunding & aborting trade", tradeBotData.getAtAddress(), crossChainTradeData.qortalPartnerAddress));
+
+				return true;
+			}
+
+		if (atData.getIsFinished() && crossChainTradeData.mode == AcctMode.REDEEMED && isAtLockedToUs) {
+			// We've redeemed already?
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_DONE,
+					() -> String.format("AT %s already redeemed by us. Trade completed", tradeBotData.getAtAddress()));
+		} else {
+			// Any other state is not good, so start defensive refund
+			TradeBot.updateTradeBotState(repository, tradeBotData, State.ALICE_REFUNDING_A,
+					() -> String.format("AT %s cancelled/refunded/redeemed by someone else/invalid state. Refunding & aborting trade", tradeBotData.getAtAddress()));
+		}
+
+		return true;
+	}
+
+	private long calcFeeTimestamp(int lockTimeA, int tradeTimeout) {
+		return (lockTimeA - tradeTimeout * 60) * 1000L;
+	}
+
+}

src/main/java/org/qortal/controller/tradebot/TradeBot.java

@@ -31,6 +31,7 @@ import org.qortal.gui.SysTray;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
 import org.qortal.repository.RepositoryManager;
+import org.qortal.repository.hsqldb.HSQLDBImportExport;
 import org.qortal.settings.Settings;
 import org.qortal.transaction.PresenceTransaction;
 import org.qortal.transaction.PresenceTransaction.PresenceType;
@@ -76,7 +77,11 @@ public class TradeBot implements Listener {
 	static {
 		acctTradeBotSuppliers.put(BitcoinACCTv1.class, BitcoinACCTv1TradeBot::getInstance);
 		acctTradeBotSuppliers.put(LitecoinACCTv1.class, LitecoinACCTv1TradeBot::getInstance);
+		acctTradeBotSuppliers.put(LitecoinACCTv2.class, LitecoinACCTv2TradeBot::getInstance);
+		acctTradeBotSuppliers.put(LitecoinACCTv3.class, LitecoinACCTv3TradeBot::getInstance);
 		acctTradeBotSuppliers.put(DogecoinACCTv1.class, DogecoinACCTv1TradeBot::getInstance);
+		acctTradeBotSuppliers.put(DogecoinACCTv2.class, DogecoinACCTv2TradeBot::getInstance);
+		acctTradeBotSuppliers.put(DogecoinACCTv3.class, DogecoinACCTv3TradeBot::getInstance);
 	}
 
 	private static TradeBot instance;
@@ -245,17 +250,17 @@ public class TradeBot implements Listener {
 		}
 	}
 
-	/*package*/ static byte[] generateTradePrivateKey() {
+	public static byte[] generateTradePrivateKey() {
 		// The private key is used for both Curve25519 and secp256k1 so needs to be valid for both.
 		// Curve25519 accepts any seed, so generate a valid secp256k1 key and use that.
 		return new ECKey().getPrivKeyBytes();
 	}
 
-	/*package*/ static byte[] deriveTradeNativePublicKey(byte[] privateKey) {
+	public static byte[] deriveTradeNativePublicKey(byte[] privateKey) {
 		return PrivateKeyAccount.toPublicKey(privateKey);
 	}
 
-	/*package*/ static byte[] deriveTradeForeignPublicKey(byte[] privateKey) {
+	public static byte[] deriveTradeForeignPublicKey(byte[] privateKey) {
 		return ECKey.fromPrivate(privateKey).getPubKey();
 	}
 
@@ -265,11 +270,11 @@ public class TradeBot implements Listener {
 		return secret;
 	}
 
-	/*package*/ static void backupTradeBotData(Repository repository) {
+	/*package*/ static void backupTradeBotData(Repository repository, List<TradeBotData> additional) {
 		// Attempt to backup the trade bot data. This an optional step and doesn't impact trading, so don't throw an exception on failure
 		try {
 			LOGGER.info("About to backup trade bot data...");
-			repository.exportNodeLocalData();
+			HSQLDBImportExport.backupTradeBotStates(repository, additional);
 		} catch (DataException e) {
 			LOGGER.info(String.format("Repository issue when exporting trade bot data: %s", e.getMessage()));
 		}

src/main/java/org/qortal/crosschain/Bitcoin.java

@@ -42,36 +42,30 @@ public class Bitcoin extends Bitcoiny {
 			public Collection<ElectrumX.Server> getServers() {
 				return Arrays.asList(
 						// Servers chosen on NO BASIS WHATSOEVER from various sources!
-						new Server("128.0.190.26", Server.ConnectionType.SSL, 50002),
 						new Server("hodlers.beer", Server.ConnectionType.SSL, 50002),
-						new Server("electrumx.erbium.eu", Server.ConnectionType.TCP, 50001),
-						new Server("electrumx.erbium.eu", Server.ConnectionType.SSL, 50002),
 						new Server("btc.lastingcoin.net", Server.ConnectionType.SSL, 50002),
 						new Server("electrum.bitaroo.net", Server.ConnectionType.SSL, 50002),
 						new Server("bitcoin.grey.pw", Server.ConnectionType.SSL, 50002),
-						new Server("2electrumx.hopto.me", Server.ConnectionType.SSL, 56022),
 						new Server("185.64.116.15", Server.ConnectionType.SSL, 50002),
-						new Server("kirsche.emzy.de", Server.ConnectionType.SSL, 50002),
 						new Server("alviss.coinjoined.com", Server.ConnectionType.SSL, 50002),
-						new Server("electrum.emzy.de", Server.ConnectionType.SSL, 50002),
-						new Server("electrum.emzy.de", Server.ConnectionType.TCP, 50001),
-						new Server("vmd71287.contaboserver.net", Server.ConnectionType.SSL, 50002),
 						new Server("btc.litepay.ch", Server.ConnectionType.SSL, 50002),
-						new Server("electrum.stippy.com", Server.ConnectionType.SSL, 50002),
 						new Server("xtrum.com", Server.ConnectionType.SSL, 50002),
 						new Server("electrum.acinq.co", Server.ConnectionType.SSL, 50002),
-						new Server("electrum2.taborsky.cz", Server.ConnectionType.SSL, 50002),
-						new Server("vmd63185.contaboserver.net", Server.ConnectionType.SSL, 50002),
-						new Server("electrum2.privateservers.network", Server.ConnectionType.SSL, 50002),
-						new Server("electrumx.alexridevski.net", Server.ConnectionType.SSL, 50002),
-						new Server("192.166.219.200", Server.ConnectionType.SSL, 50002),
-						new Server("2ex.digitaleveryware.com", Server.ConnectionType.SSL, 50002),
-						new Server("dxm.no-ip.biz", Server.ConnectionType.SSL, 50002),
 						new Server("caleb.vegas", Server.ConnectionType.SSL, 50002),
-						new Server("ecdsa.net", Server.ConnectionType.SSL, 110),
-						new Server("electrum.hsmiths.com", Server.ConnectionType.SSL, 995),
-						new Server("elec.luggs.co", Server.ConnectionType.SSL, 443),
-						new Server("btc.smsys.me", Server.ConnectionType.SSL, 995));
+						new Server("electrum.coinext.com.br", Server.ConnectionType.TCP, 50001),
+						new Server("korea.electrum-server.com", Server.ConnectionType.TCP, 50001),
+						new Server("eai.coincited.net", Server.ConnectionType.TCP, 50001),
+						new Server("electrum.coinext.com.br", Server.ConnectionType.SSL, 50002),
+						new Server("node1.btccuracao.com", Server.ConnectionType.SSL, 50002),
+						new Server("korea.electrum-server.com", Server.ConnectionType.SSL, 50002),
+						new Server("btce.iiiiiii.biz", Server.ConnectionType.SSL, 50002),
+						new Server("bitcoin.lukechilds.co", Server.ConnectionType.SSL, 50002),
+						new Server("guichet.centure.cc", Server.ConnectionType.SSL, 50002),
+						new Server("electrumx.hodlwallet.com", Server.ConnectionType.SSL, 50002),
+						new Server("eai.coincited.net", Server.ConnectionType.SSL, 50002),
+						new Server("prospero.bitsrc.net", Server.ConnectionType.SSL, 50002),
+						new Server("gd42.org", Server.ConnectionType.SSL, 50002),
+						new Server("electrum.pabu.io", Server.ConnectionType.SSL, 50002));
 			}
 
 			@Override

src/main/java/org/qortal/crosschain/DogecoinACCTv2.java

@@ -0,0 +1,861 @@
+package org.qortal.crosschain;
+
+import com.google.common.hash.HashCode;
+import com.google.common.primitives.Bytes;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.ciyam.at.*;
+import org.qortal.account.Account;
+import org.qortal.asset.Asset;
+import org.qortal.at.QortalFunctionCode;
+import org.qortal.crypto.Crypto;
+import org.qortal.data.at.ATData;
+import org.qortal.data.at.ATStateData;
+import org.qortal.data.crosschain.CrossChainTradeData;
+import org.qortal.data.transaction.MessageTransactionData;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.utils.Base58;
+import org.qortal.utils.BitTwiddling;
+
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.ciyam.at.OpCode.calcOffset;
+
+/**
+ * Cross-chain trade AT
+ * 
+ * <p>
+ * <ul>
+ * <li>Bob generates Dogecoin & Qortal 'trade' keys
+ * 		<ul>
+ * 			<li>private key required to sign P2SH redeem tx</li>
+ * 			<li>private key could be used to create 'secret' (e.g. double-SHA256)</li>
+ * 			<li>encrypted private key could be stored in Qortal AT for access by Bob from any node</li>
+ * 		</ul>
+ * </li>
+ * <li>Bob deploys Qortal AT
+ * 		<ul>
+ * 		</ul>
+ * </li>
+ * <li>Alice finds Qortal AT and wants to trade
+ * 		<ul>
+ * 			<li>Alice generates Dogecoin & Qortal 'trade' keys</li>
+ * 			<li>Alice funds Dogecoin P2SH-A</li>
+ * 			<li>Alice sends 'offer' MESSAGE to Bob from her Qortal trade address, containing:
+ * 				<ul>
+ * 					<li>hash-of-secret-A</li>
+ * 					<li>her 'trade' Dogecoin PKH</li>
+ * 				</ul>
+ * 			</li>
+ * 		</ul>
+ * </li>
+ * <li>Bob receives "offer" MESSAGE
+ * 		<ul>
+ * 			<li>Checks Alice's P2SH-A</li>
+ * 			<li>Sends 'trade' MESSAGE to Qortal AT from his trade address, containing:
+ * 				<ul>
+ * 					<li>Alice's trade Qortal address</li>
+ * 					<li>Alice's trade Dogecoin PKH</li>
+ * 					<li>hash-of-secret-A</li>
+ * 				</ul>
+ * 			</li>
+ * 		</ul>
+ * </li>
+ * <li>Alice checks Qortal AT to confirm it's locked to her
+ * 		<ul>
+ * 			<li>Alice sends 'redeem' MESSAGE to Qortal AT from her trade address, containing:
+ * 				<ul>
+ * 					<li>secret-A</li>
+ * 					<li>Qortal receiving address of her chosing</li>
+ * 				</ul>
+ * 			</li>
+ * 			<li>AT's QORT funds are sent to Qortal receiving address</li>
+ * 		</ul>
+ * </li>
+ * <li>Bob checks AT, extracts secret-A
+ * 		<ul>
+ * 			<li>Bob redeems P2SH-A using his Dogecoin trade key and secret-A</li>
+ * 			<li>P2SH-A DOGE funds end up at Dogecoin address determined by redeem transaction output(s)</li>
+ * 		</ul>
+ * </li>
+ * </ul>
+ */
+public class DogecoinACCTv2 implements ACCT {
+
+	private static final Logger LOGGER = LogManager.getLogger(DogecoinACCTv2.class);
+
+	public static final String NAME = DogecoinACCTv2.class.getSimpleName();
+	public static final byte[] CODE_BYTES_HASH = HashCode.fromString("6fff38d6eeb06568a9c879c5628527730319844aa0de53f5f4ffab5506efe885").asBytes(); // SHA256 of AT code bytes
+
+	public static final int SECRET_LENGTH = 32;
+
+	/** <b>Value</b> offset into AT segment where 'mode' variable (long) is stored. (Multiply by MachineState.VALUE_SIZE for byte offset). */
+	private static final int MODE_VALUE_OFFSET = 61;
+	/** <b>Byte</b> offset into AT state data where 'mode' variable (long) is stored. */
+	public static final int MODE_BYTE_OFFSET = MachineState.HEADER_LENGTH + (MODE_VALUE_OFFSET * MachineState.VALUE_SIZE);
+
+	public static class OfferMessageData {
+		public byte[] partnerDogecoinPKH;
+		public byte[] hashOfSecretA;
+		public long lockTimeA;
+	}
+	public static final int OFFER_MESSAGE_LENGTH = 20 /*partnerDogecoinPKH*/ + 20 /*hashOfSecretA*/ + 8 /*lockTimeA*/;
+	public static final int TRADE_MESSAGE_LENGTH = 32 /*partner's Qortal trade address (padded from 25 to 32)*/
+			+ 24 /*partner's Dogecoin PKH (padded from 20 to 24)*/
+			+ 8 /*AT trade timeout (minutes)*/
+			+ 24 /*hash of secret-A (padded from 20 to 24)*/
+			+ 8 /*lockTimeA*/;
+	public static final int REDEEM_MESSAGE_LENGTH = 32 /*secret-A*/ + 32 /*partner's Qortal receiving address padded from 25 to 32*/;
+	public static final int CANCEL_MESSAGE_LENGTH = 32 /*AT creator's Qortal address*/;
+
+	private static DogecoinACCTv2 instance;
+
+	private DogecoinACCTv2() {
+	}
+
+	public static synchronized DogecoinACCTv2 getInstance() {
+		if (instance == null)
+			instance = new DogecoinACCTv2();
+
+		return instance;
+	}
+
+	@Override
+	public byte[] getCodeBytesHash() {
+		return CODE_BYTES_HASH;
+	}
+
+	@Override
+	public int getModeByteOffset() {
+		return MODE_BYTE_OFFSET;
+	}
+
+	@Override
+	public ForeignBlockchain getBlockchain() {
+		return Dogecoin.getInstance();
+	}
+
+	/**
+	 * Returns Qortal AT creation bytes for cross-chain trading AT.
+	 * <p>
+	 * <tt>tradeTimeout</tt> (minutes) is the time window for the trade partner to send the
+	 * 32-byte secret to the AT, before the AT automatically refunds the AT's creator.
+	 * 
+	 * @param creatorTradeAddress AT creator's trade Qortal address
+	 * @param dogecoinPublicKeyHash 20-byte HASH160 of creator's trade Dogecoin public key
+	 * @param qortAmount how much QORT to pay trade partner if they send correct 32-byte secrets to AT
+	 * @param dogecoinAmount how much DOGE the AT creator is expecting to trade
+	 * @param tradeTimeout suggested timeout for entire trade
+	 */
+	public static byte[] buildQortalAT(String creatorTradeAddress, byte[] dogecoinPublicKeyHash, long qortAmount, long dogecoinAmount, int tradeTimeout) {
+		if (dogecoinPublicKeyHash.length != 20)
+			throw new IllegalArgumentException("Dogecoin public key hash should be 20 bytes");
+
+		// Labels for data segment addresses
+		int addrCounter = 0;
+
+		// Constants (with corresponding dataByteBuffer.put*() calls below)
+
+		final int addrCreatorTradeAddress1 = addrCounter++;
+		final int addrCreatorTradeAddress2 = addrCounter++;
+		final int addrCreatorTradeAddress3 = addrCounter++;
+		final int addrCreatorTradeAddress4 = addrCounter++;
+
+		final int addrDogecoinPublicKeyHash = addrCounter;
+		addrCounter += 4;
+
+		final int addrQortAmount = addrCounter++;
+		final int addrDogecoinAmount = addrCounter++;
+		final int addrTradeTimeout = addrCounter++;
+
+		final int addrMessageTxnType = addrCounter++;
+		final int addrExpectedTradeMessageLength = addrCounter++;
+		final int addrExpectedRedeemMessageLength = addrCounter++;
+
+		final int addrCreatorAddressPointer = addrCounter++;
+		final int addrQortalPartnerAddressPointer = addrCounter++;
+		final int addrMessageSenderPointer = addrCounter++;
+
+		final int addrTradeMessagePartnerDogecoinPKHOffset = addrCounter++;
+		final int addrPartnerDogecoinPKHPointer = addrCounter++;
+		final int addrTradeMessageHashOfSecretAOffset = addrCounter++;
+		final int addrHashOfSecretAPointer = addrCounter++;
+
+		final int addrRedeemMessageReceivingAddressOffset = addrCounter++;
+
+		final int addrMessageDataPointer = addrCounter++;
+		final int addrMessageDataLength = addrCounter++;
+
+		final int addrPartnerReceivingAddressPointer = addrCounter++;
+
+		final int addrEndOfConstants = addrCounter;
+
+		// Variables
+
+		final int addrCreatorAddress1 = addrCounter++;
+		final int addrCreatorAddress2 = addrCounter++;
+		final int addrCreatorAddress3 = addrCounter++;
+		final int addrCreatorAddress4 = addrCounter++;
+
+		final int addrQortalPartnerAddress1 = addrCounter++;
+		final int addrQortalPartnerAddress2 = addrCounter++;
+		final int addrQortalPartnerAddress3 = addrCounter++;
+		final int addrQortalPartnerAddress4 = addrCounter++;
+
+		final int addrLockTimeA = addrCounter++;
+		final int addrRefundTimeout = addrCounter++;
+		final int addrRefundTimestamp = addrCounter++;
+		final int addrLastTxnTimestamp = addrCounter++;
+		final int addrBlockTimestamp = addrCounter++;
+		final int addrTxnType = addrCounter++;
+		final int addrResult = addrCounter++;
+
+		final int addrMessageSender1 = addrCounter++;
+		final int addrMessageSender2 = addrCounter++;
+		final int addrMessageSender3 = addrCounter++;
+		final int addrMessageSender4 = addrCounter++;
+
+		final int addrMessageLength = addrCounter++;
+
+		final int addrMessageData = addrCounter;
+		addrCounter += 4;
+
+		final int addrHashOfSecretA = addrCounter;
+		addrCounter += 4;
+
+		final int addrPartnerDogecoinPKH = addrCounter;
+		addrCounter += 4;
+
+		final int addrPartnerReceivingAddress = addrCounter;
+		addrCounter += 4;
+
+		final int addrMode = addrCounter++;
+		assert addrMode == MODE_VALUE_OFFSET : String.format("addrMode %d does not match MODE_VALUE_OFFSET %d", addrMode, MODE_VALUE_OFFSET);
+
+		// Data segment
+		ByteBuffer dataByteBuffer = ByteBuffer.allocate(addrCounter * MachineState.VALUE_SIZE);
+
+		// AT creator's trade Qortal address, decoded from Base58
+		assert dataByteBuffer.position() == addrCreatorTradeAddress1 * MachineState.VALUE_SIZE : "addrCreatorTradeAddress1 incorrect";
+		byte[] creatorTradeAddressBytes = Base58.decode(creatorTradeAddress);
+		dataByteBuffer.put(Bytes.ensureCapacity(creatorTradeAddressBytes, 32, 0));
+
+		// Dogecoin public key hash
+		assert dataByteBuffer.position() == addrDogecoinPublicKeyHash * MachineState.VALUE_SIZE : "addrDogecoinPublicKeyHash incorrect";
+		dataByteBuffer.put(Bytes.ensureCapacity(dogecoinPublicKeyHash, 32, 0));
+
+		// Redeem Qort amount
+		assert dataByteBuffer.position() == addrQortAmount * MachineState.VALUE_SIZE : "addrQortAmount incorrect";
+		dataByteBuffer.putLong(qortAmount);
+
+		// Expected Dogecoin amount
+		assert dataByteBuffer.position() == addrDogecoinAmount * MachineState.VALUE_SIZE : "addrDogecoinAmount incorrect";
+		dataByteBuffer.putLong(dogecoinAmount);
+
+		// Suggested trade timeout (minutes)
+		assert dataByteBuffer.position() == addrTradeTimeout * MachineState.VALUE_SIZE : "addrTradeTimeout incorrect";
+		dataByteBuffer.putLong(tradeTimeout);
+
+		// We're only interested in MESSAGE transactions
+		assert dataByteBuffer.position() == addrMessageTxnType * MachineState.VALUE_SIZE : "addrMessageTxnType incorrect";
+		dataByteBuffer.putLong(API.ATTransactionType.MESSAGE.value);
+
+		// Expected length of 'trade' MESSAGE data from AT creator
+		assert dataByteBuffer.position() == addrExpectedTradeMessageLength * MachineState.VALUE_SIZE : "addrExpectedTradeMessageLength incorrect";
+		dataByteBuffer.putLong(TRADE_MESSAGE_LENGTH);
+
+		// Expected length of 'redeem' MESSAGE data from trade partner
+		assert dataByteBuffer.position() == addrExpectedRedeemMessageLength * MachineState.VALUE_SIZE : "addrExpectedRedeemMessageLength incorrect";
+		dataByteBuffer.putLong(REDEEM_MESSAGE_LENGTH);
+
+		// Index into data segment of AT creator's address, used by GET_B_IND
+		assert dataByteBuffer.position() == addrCreatorAddressPointer * MachineState.VALUE_SIZE : "addrCreatorAddressPointer incorrect";
+		dataByteBuffer.putLong(addrCreatorAddress1);
+
+		// Index into data segment of partner's Qortal address, used by SET_B_IND
+		assert dataByteBuffer.position() == addrQortalPartnerAddressPointer * MachineState.VALUE_SIZE : "addrQortalPartnerAddressPointer incorrect";
+		dataByteBuffer.putLong(addrQortalPartnerAddress1);
+
+		// Index into data segment of (temporary) transaction's sender's address, used by GET_B_IND
+		assert dataByteBuffer.position() == addrMessageSenderPointer * MachineState.VALUE_SIZE : "addrMessageSenderPointer incorrect";
+		dataByteBuffer.putLong(addrMessageSender1);
+
+		// Offset into 'trade' MESSAGE data payload for extracting partner's Dogecoin PKH
+		assert dataByteBuffer.position() == addrTradeMessagePartnerDogecoinPKHOffset * MachineState.VALUE_SIZE : "addrTradeMessagePartnerDogecoinPKHOffset incorrect";
+		dataByteBuffer.putLong(32L);
+
+		// Index into data segment of partner's Dogecoin PKH, used by GET_B_IND
+		assert dataByteBuffer.position() == addrPartnerDogecoinPKHPointer * MachineState.VALUE_SIZE : "addrPartnerDogecoinPKHPointer incorrect";
+		dataByteBuffer.putLong(addrPartnerDogecoinPKH);
+
+		// Offset into 'trade' MESSAGE data payload for extracting hash-of-secret-A
+		assert dataByteBuffer.position() == addrTradeMessageHashOfSecretAOffset * MachineState.VALUE_SIZE : "addrTradeMessageHashOfSecretAOffset incorrect";
+		dataByteBuffer.putLong(64L);
+
+		// Index into data segment to hash of secret A, used by GET_B_IND
+		assert dataByteBuffer.position() == addrHashOfSecretAPointer * MachineState.VALUE_SIZE : "addrHashOfSecretAPointer incorrect";
+		dataByteBuffer.putLong(addrHashOfSecretA);
+
+		// Offset into 'redeem' MESSAGE data payload for extracting Qortal receiving address
+		assert dataByteBuffer.position() == addrRedeemMessageReceivingAddressOffset * MachineState.VALUE_SIZE : "addrRedeemMessageReceivingAddressOffset incorrect";
+		dataByteBuffer.putLong(32L);
+
+		// Source location and length for hashing any passed secret
+		assert dataByteBuffer.position() == addrMessageDataPointer * MachineState.VALUE_SIZE : "addrMessageDataPointer incorrect";
+		dataByteBuffer.putLong(addrMessageData);
+		assert dataByteBuffer.position() == addrMessageDataLength * MachineState.VALUE_SIZE : "addrMessageDataLength incorrect";
+		dataByteBuffer.putLong(32L);
+
+		// Pointer into data segment of where to save partner's receiving Qortal address, used by GET_B_IND
+		assert dataByteBuffer.position() == addrPartnerReceivingAddressPointer * MachineState.VALUE_SIZE : "addrPartnerReceivingAddressPointer incorrect";
+		dataByteBuffer.putLong(addrPartnerReceivingAddress);
+
+		assert dataByteBuffer.position() == addrEndOfConstants * MachineState.VALUE_SIZE : "dataByteBuffer position not at end of constants";
+
+		// Code labels
+		Integer labelRefund = null;
+
+		Integer labelTradeTxnLoop = null;
+		Integer labelCheckTradeTxn = null;
+		Integer labelCheckCancelTxn = null;
+		Integer labelNotTradeNorCancelTxn = null;
+		Integer labelCheckNonRefundTradeTxn = null;
+		Integer labelTradeTxnExtract = null;
+		Integer labelRedeemTxnLoop = null;
+		Integer labelCheckRedeemTxn = null;
+		Integer labelCheckRedeemTxnSender = null;
+		Integer labelPayout = null;
+
+		ByteBuffer codeByteBuffer = ByteBuffer.allocate(768);
+
+		// Two-pass version
+		for (int pass = 0; pass < 2; ++pass) {
+			codeByteBuffer.clear();
+
+			try {
+				/* Initialization */
+
+				/* NOP - to ensure DOGECOIN ACCT is unique */
+				codeByteBuffer.put(OpCode.NOP.compile());
+
+				// Use AT creation 'timestamp' as starting point for finding transactions sent to AT
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_CREATION_TIMESTAMP, addrLastTxnTimestamp));
+
+				// Load B register with AT creator's address so we can save it into addrCreatorAddress1-4
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_CREATOR_INTO_B));
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrCreatorAddressPointer));
+
+				// Set restart position to after this opcode
+				codeByteBuffer.put(OpCode.SET_PCS.compile());
+
+				/* Loop, waiting for message from AT creator's trade address containing trade partner details, or AT owner's address to cancel offer */
+
+				/* Transaction processing loop */
+				labelTradeTxnLoop = codeByteBuffer.position();
+
+				/* Sleep until message arrives */
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.SLEEP_UNTIL_MESSAGE.value, addrLastTxnTimestamp));
+
+				// Find next transaction (if any) to this AT since the last one (referenced by addrLastTxnTimestamp)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PUT_TX_AFTER_TIMESTAMP_INTO_A, addrLastTxnTimestamp));
+				// If no transaction found, A will be zero. If A is zero, set addrResult to 1, otherwise 0.
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.CHECK_A_IS_ZERO, addrResult));
+				// If addrResult is zero (i.e. A is non-zero, transaction was found) then go check transaction
+				codeByteBuffer.put(OpCode.BZR_DAT.compile(addrResult, calcOffset(codeByteBuffer, labelCheckTradeTxn)));
+				// Stop and wait for next block
+				codeByteBuffer.put(OpCode.STP_IMD.compile());
+
+				/* Check transaction */
+				labelCheckTradeTxn = codeByteBuffer.position();
+
+				// Update our 'last found transaction's timestamp' using 'timestamp' from transaction
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TIMESTAMP_FROM_TX_IN_A, addrLastTxnTimestamp));
+				// Extract transaction type (message/payment) from transaction and save type in addrTxnType
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TYPE_FROM_TX_IN_A, addrTxnType));
+				// If transaction type is not MESSAGE type then go look for another transaction
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrTxnType, addrMessageTxnType, calcOffset(codeByteBuffer, labelTradeTxnLoop)));
+
+				/* Check transaction's sender. We're expecting AT creator's trade address for 'trade' message, or AT creator's own address for 'cancel' message. */
+
+				// Extract sender address from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_ADDRESS_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrMessageSender1 (as pointed to by addrMessageSenderPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrMessageSenderPointer));
+				// Compare each part of message sender's address with AT creator's trade address. If they don't match, check for cancel situation.
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender1, addrCreatorTradeAddress1, calcOffset(codeByteBuffer, labelCheckCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender2, addrCreatorTradeAddress2, calcOffset(codeByteBuffer, labelCheckCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender3, addrCreatorTradeAddress3, calcOffset(codeByteBuffer, labelCheckCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender4, addrCreatorTradeAddress4, calcOffset(codeByteBuffer, labelCheckCancelTxn)));
+				// Message sender's address matches AT creator's trade address so go process 'trade' message
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelCheckNonRefundTradeTxn == null ? 0 : labelCheckNonRefundTradeTxn));
+
+				/* Checking message sender for possible cancel message */
+				labelCheckCancelTxn = codeByteBuffer.position();
+
+				// Compare each part of message sender's address with AT creator's address. If they don't match, look for another transaction.
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender1, addrCreatorAddress1, calcOffset(codeByteBuffer, labelNotTradeNorCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender2, addrCreatorAddress2, calcOffset(codeByteBuffer, labelNotTradeNorCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender3, addrCreatorAddress3, calcOffset(codeByteBuffer, labelNotTradeNorCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender4, addrCreatorAddress4, calcOffset(codeByteBuffer, labelNotTradeNorCancelTxn)));
+				// Partner address is AT creator's address, so cancel offer and finish.
+				codeByteBuffer.put(OpCode.SET_VAL.compile(addrMode, AcctMode.CANCELLED.value));
+				// We're finished forever (finishing auto-refunds remaining balance to AT creator)
+				codeByteBuffer.put(OpCode.FIN_IMD.compile());
+
+				/* Not trade nor cancel message */
+				labelNotTradeNorCancelTxn = codeByteBuffer.position();
+
+				// Loop to find another transaction
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelTradeTxnLoop == null ? 0 : labelTradeTxnLoop));
+
+				/* Possible switch-to-trade-mode message */
+				labelCheckNonRefundTradeTxn = codeByteBuffer.position();
+
+				// Check 'trade' message we received has expected number of message bytes
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(QortalFunctionCode.GET_MESSAGE_LENGTH_FROM_TX_IN_A.value, addrMessageLength));
+				// If message length matches, branch to info extraction code
+				codeByteBuffer.put(OpCode.BEQ_DAT.compile(addrMessageLength, addrExpectedTradeMessageLength, calcOffset(codeByteBuffer, labelTradeTxnExtract)));
+				// Message length didn't match - go back to finding another 'trade' MESSAGE transaction
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelTradeTxnLoop == null ? 0 : labelTradeTxnLoop));
+
+				/* Extracting info from 'trade' MESSAGE transaction */
+				labelTradeTxnExtract = codeByteBuffer.position();
+
+				// Extract message from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_MESSAGE_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrQortalPartnerAddress1 (as pointed to by addrQortalPartnerAddressPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrQortalPartnerAddressPointer));
+
+				// Extract trade partner's Dogecoin public key hash (PKH) from message into B
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.PUT_PARTIAL_MESSAGE_FROM_TX_IN_A_INTO_B.value, addrTradeMessagePartnerDogecoinPKHOffset));
+				// Store partner's Dogecoin PKH (we only really use values from B1-B3)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrPartnerDogecoinPKHPointer));
+				// Extract AT trade timeout (minutes) (from B4)
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_B4, addrRefundTimeout));
+
+				// Grab next 32 bytes
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.PUT_PARTIAL_MESSAGE_FROM_TX_IN_A_INTO_B.value, addrTradeMessageHashOfSecretAOffset));
+
+				// Extract hash-of-secret-A (we only really use values from B1-B3)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrHashOfSecretAPointer));
+				// Extract lockTime-A (from B4)
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_B4, addrLockTimeA));
+
+				// Calculate trade timeout refund 'timestamp' by adding addrRefundTimeout minutes to this transaction's 'timestamp', then save into addrRefundTimestamp
+				codeByteBuffer.put(OpCode.EXT_FUN_RET_DAT_2.compile(FunctionCode.ADD_MINUTES_TO_TIMESTAMP, addrRefundTimestamp, addrLastTxnTimestamp, addrRefundTimeout));
+
+				/* We are in 'trade mode' */
+				codeByteBuffer.put(OpCode.SET_VAL.compile(addrMode, AcctMode.TRADING.value));
+
+				// Set restart position to after this opcode
+				codeByteBuffer.put(OpCode.SET_PCS.compile());
+
+				/* Loop, waiting for trade timeout or 'redeem' MESSAGE from Qortal trade partner */
+
+				// Fetch current block 'timestamp'
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_BLOCK_TIMESTAMP, addrBlockTimestamp));
+				// If we're not past refund 'timestamp' then look for next transaction
+				codeByteBuffer.put(OpCode.BLT_DAT.compile(addrBlockTimestamp, addrRefundTimestamp, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+				// We're past refund 'timestamp' so go refund everything back to AT creator
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelRefund == null ? 0 : labelRefund));
+
+				/* Transaction processing loop */
+				labelRedeemTxnLoop = codeByteBuffer.position();
+
+				/* Sleep until message arrives */
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.SLEEP_UNTIL_MESSAGE.value, addrLastTxnTimestamp));
+
+				// Find next transaction to this AT since the last one (if any)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PUT_TX_AFTER_TIMESTAMP_INTO_A, addrLastTxnTimestamp));
+				// If no transaction found, A will be zero. If A is zero, set addrComparator to 1, otherwise 0.
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.CHECK_A_IS_ZERO, addrResult));
+				// If addrResult is zero (i.e. A is non-zero, transaction was found) then go check transaction
+				codeByteBuffer.put(OpCode.BZR_DAT.compile(addrResult, calcOffset(codeByteBuffer, labelCheckRedeemTxn)));
+				// Stop and wait for next block
+				codeByteBuffer.put(OpCode.STP_IMD.compile());
+
+				/* Check transaction */
+				labelCheckRedeemTxn = codeByteBuffer.position();
+
+				// Update our 'last found transaction's timestamp' using 'timestamp' from transaction
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TIMESTAMP_FROM_TX_IN_A, addrLastTxnTimestamp));
+				// Extract transaction type (message/payment) from transaction and save type in addrTxnType
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TYPE_FROM_TX_IN_A, addrTxnType));
+				// If transaction type is not MESSAGE type then go look for another transaction
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrTxnType, addrMessageTxnType, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+
+				/* Check message payload length */
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(QortalFunctionCode.GET_MESSAGE_LENGTH_FROM_TX_IN_A.value, addrMessageLength));
+				// If message length matches, branch to sender checking code
+				codeByteBuffer.put(OpCode.BEQ_DAT.compile(addrMessageLength, addrExpectedRedeemMessageLength, calcOffset(codeByteBuffer, labelCheckRedeemTxnSender)));
+				// Message length didn't match - go back to finding another 'redeem' MESSAGE transaction
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelRedeemTxnLoop == null ? 0 : labelRedeemTxnLoop));
+
+				/* Check transaction's sender */
+				labelCheckRedeemTxnSender = codeByteBuffer.position();
+
+				// Extract sender address from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_ADDRESS_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrMessageSender1 (as pointed to by addrMessageSenderPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrMessageSenderPointer));
+				// Compare each part of transaction's sender's address with expected address. If they don't match, look for another transaction.
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender1, addrQortalPartnerAddress1, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender2, addrQortalPartnerAddress2, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender3, addrQortalPartnerAddress3, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender4, addrQortalPartnerAddress4, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+
+				/* Check 'secret-A' in transaction's message */
+
+				// Extract secret-A from first 32 bytes of message from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_MESSAGE_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrMessageData (as pointed to by addrMessageDataPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrMessageDataPointer));
+				// Load B register with expected hash result (as pointed to by addrHashOfSecretAPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.SET_B_IND, addrHashOfSecretAPointer));
+				// Perform HASH160 using source data at addrMessageData. (Location and length specified via addrMessageDataPointer and addrMessageDataLength).
+				// Save the equality result (1 if they match, 0 otherwise) into addrResult.
+				codeByteBuffer.put(OpCode.EXT_FUN_RET_DAT_2.compile(FunctionCode.CHECK_HASH160_WITH_B, addrResult, addrMessageDataPointer, addrMessageDataLength));
+				// If hashes don't match, addrResult will be zero so go find another transaction
+				codeByteBuffer.put(OpCode.BNZ_DAT.compile(addrResult, calcOffset(codeByteBuffer, labelPayout)));
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelRedeemTxnLoop == null ? 0 : labelRedeemTxnLoop));
+
+				/* Success! Pay arranged amount to receiving address */
+				labelPayout = codeByteBuffer.position();
+
+				// Extract Qortal receiving address from next 32 bytes of message from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.PUT_PARTIAL_MESSAGE_FROM_TX_IN_A_INTO_B.value, addrRedeemMessageReceivingAddressOffset));
+				// Save B register into data segment starting at addrPartnerReceivingAddress (as pointed to by addrPartnerReceivingAddressPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrPartnerReceivingAddressPointer));
+				// Pay AT's balance to receiving address
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PAY_TO_ADDRESS_IN_B, addrQortAmount));
+				// Set redeemed mode
+				codeByteBuffer.put(OpCode.SET_VAL.compile(addrMode, AcctMode.REDEEMED.value));
+				// We're finished forever (finishing auto-refunds remaining balance to AT creator)
+				codeByteBuffer.put(OpCode.FIN_IMD.compile());
+
+				// Fall-through to refunding any remaining balance back to AT creator
+
+				/* Refund balance back to AT creator */
+				labelRefund = codeByteBuffer.position();
+
+				// Set refunded mode
+				codeByteBuffer.put(OpCode.SET_VAL.compile(addrMode, AcctMode.REFUNDED.value));
+				// We're finished forever (finishing auto-refunds remaining balance to AT creator)
+				codeByteBuffer.put(OpCode.FIN_IMD.compile());
+			} catch (CompilationException e) {
+				throw new IllegalStateException("Unable to compile DOGE-QORT ACCT?", e);
+			}
+		}
+
+		codeByteBuffer.flip();
+
+		byte[] codeBytes = new byte[codeByteBuffer.limit()];
+		codeByteBuffer.get(codeBytes);
+
+		assert Arrays.equals(Crypto.digest(codeBytes), DogecoinACCTv2.CODE_BYTES_HASH)
+			: String.format("BTCACCT.CODE_BYTES_HASH mismatch: expected %s, actual %s", HashCode.fromBytes(CODE_BYTES_HASH), HashCode.fromBytes(Crypto.digest(codeBytes)));
+
+		final short ciyamAtVersion = 2;
+		final short numCallStackPages = 0;
+		final short numUserStackPages = 0;
+		final long minActivationAmount = 0L;
+
+		return MachineState.toCreationBytes(ciyamAtVersion, codeBytes, dataByteBuffer.array(), numCallStackPages, numUserStackPages, minActivationAmount);
+	}
+
+	/**
+	 * Returns CrossChainTradeData with useful info extracted from AT.
+	 */
+	@Override
+	public CrossChainTradeData populateTradeData(Repository repository, ATData atData) throws DataException {
+		ATStateData atStateData = repository.getATRepository().getLatestATState(atData.getATAddress());
+		return populateTradeData(repository, atData.getCreatorPublicKey(), atData.getCreation(), atStateData);
+	}
+
+	/**
+	 * Returns CrossChainTradeData with useful info extracted from AT.
+	 */
+	@Override
+	public CrossChainTradeData populateTradeData(Repository repository, ATStateData atStateData) throws DataException {
+		ATData atData = repository.getATRepository().fromATAddress(atStateData.getATAddress());
+		return populateTradeData(repository, atData.getCreatorPublicKey(), atData.getCreation(), atStateData);
+	}
+
+	/**
+	 * Returns CrossChainTradeData with useful info extracted from AT.
+	 */
+	public CrossChainTradeData populateTradeData(Repository repository, byte[] creatorPublicKey, long creationTimestamp, ATStateData atStateData) throws DataException {
+		byte[] addressBytes = new byte[25]; // for general use
+		String atAddress = atStateData.getATAddress();
+
+		CrossChainTradeData tradeData = new CrossChainTradeData();
+
+		tradeData.foreignBlockchain = SupportedBlockchain.DOGECOIN.name();
+		tradeData.acctName = NAME;
+
+		tradeData.qortalAtAddress = atAddress;
+		tradeData.qortalCreator = Crypto.toAddress(creatorPublicKey);
+		tradeData.creationTimestamp = creationTimestamp;
+
+		Account atAccount = new Account(repository, atAddress);
+		tradeData.qortBalance = atAccount.getConfirmedBalance(Asset.QORT);
+
+		byte[] stateData = atStateData.getStateData();
+		ByteBuffer dataByteBuffer = ByteBuffer.wrap(stateData);
+		dataByteBuffer.position(MachineState.HEADER_LENGTH);
+
+		/* Constants */
+
+		// Skip creator's trade address
+		dataByteBuffer.get(addressBytes);
+		tradeData.qortalCreatorTradeAddress = Base58.encode(addressBytes);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - addressBytes.length);
+
+		// Creator's Dogecoin/foreign public key hash
+		tradeData.creatorForeignPKH = new byte[20];
+		dataByteBuffer.get(tradeData.creatorForeignPKH);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - tradeData.creatorForeignPKH.length); // skip to 32 bytes
+
+		// We don't use secret-B
+		tradeData.hashOfSecretB = null;
+
+		// Redeem payout
+		tradeData.qortAmount = dataByteBuffer.getLong();
+
+		// Expected DOGE amount
+		tradeData.expectedForeignAmount = dataByteBuffer.getLong();
+
+		// Trade timeout
+		tradeData.tradeTimeout = (int) dataByteBuffer.getLong();
+
+		// Skip MESSAGE transaction type
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip expected 'trade' message length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip expected 'redeem' message length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to creator's address
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to partner's Qortal trade address
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to message sender
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip 'trade' message data offset for partner's Dogecoin PKH
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to partner's Dogecoin PKH
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip 'trade' message data offset for hash-of-secret-A
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to hash-of-secret-A
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip 'redeem' message data offset for partner's Qortal receiving address
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to message data
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip message data length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to partner's receiving address
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		/* End of constants / begin variables */
+
+		// Skip AT creator's address
+		dataByteBuffer.position(dataByteBuffer.position() + 8 * 4);
+
+		// Partner's trade address (if present)
+		dataByteBuffer.get(addressBytes);
+		String qortalRecipient = Base58.encode(addressBytes);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - addressBytes.length);
+
+		// Potential lockTimeA (if in trade mode)
+		int lockTimeA = (int) dataByteBuffer.getLong();
+
+		// AT refund timeout (probably only useful for debugging)
+		int refundTimeout = (int) dataByteBuffer.getLong();
+
+		// Trade-mode refund timestamp (AT 'timestamp' converted to Qortal block height)
+		long tradeRefundTimestamp = dataByteBuffer.getLong();
+
+		// Skip last transaction timestamp
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip block timestamp
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip transaction type
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip temporary result
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip temporary message sender
+		dataByteBuffer.position(dataByteBuffer.position() + 8 * 4);
+
+		// Skip message length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip temporary message data
+		dataByteBuffer.position(dataByteBuffer.position() + 8 * 4);
+
+		// Potential hash160 of secret A
+		byte[] hashOfSecretA = new byte[20];
+		dataByteBuffer.get(hashOfSecretA);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - hashOfSecretA.length); // skip to 32 bytes
+
+		// Potential partner's Dogecoin PKH
+		byte[] partnerDogecoinPKH = new byte[20];
+		dataByteBuffer.get(partnerDogecoinPKH);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - partnerDogecoinPKH.length); // skip to 32 bytes
+
+		// Partner's receiving address (if present)
+		byte[] partnerReceivingAddress = new byte[25];
+		dataByteBuffer.get(partnerReceivingAddress);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - partnerReceivingAddress.length); // skip to 32 bytes
+
+		// Trade AT's 'mode'
+		long modeValue = dataByteBuffer.getLong();
+		AcctMode mode = AcctMode.valueOf((int) (modeValue & 0xffL));
+
+		/* End of variables */
+
+		if (mode != null && mode != AcctMode.OFFERING) {
+			tradeData.mode = mode;
+			tradeData.refundTimeout = refundTimeout;
+			tradeData.tradeRefundHeight = new Timestamp(tradeRefundTimestamp).blockHeight;
+			tradeData.qortalPartnerAddress = qortalRecipient;
+			tradeData.hashOfSecretA = hashOfSecretA;
+			tradeData.partnerForeignPKH = partnerDogecoinPKH;
+			tradeData.lockTimeA = lockTimeA;
+
+			if (mode == AcctMode.REDEEMED)
+				tradeData.qortalPartnerReceivingAddress = Base58.encode(partnerReceivingAddress);
+		} else {
+			tradeData.mode = AcctMode.OFFERING;
+		}
+
+		tradeData.duplicateDeprecated();
+
+		return tradeData;
+	}
+
+	/** Returns 'offer' MESSAGE payload for trade partner to send to AT creator's trade address. */
+	public static byte[] buildOfferMessage(byte[] partnerBitcoinPKH, byte[] hashOfSecretA, int lockTimeA) {
+		byte[] lockTimeABytes = BitTwiddling.toBEByteArray((long) lockTimeA);
+		return Bytes.concat(partnerBitcoinPKH, hashOfSecretA, lockTimeABytes);
+	}
+
+	/** Returns info extracted from 'offer' MESSAGE payload sent by trade partner to AT creator's trade address, or null if not valid. */
+	public static OfferMessageData extractOfferMessageData(byte[] messageData) {
+		if (messageData == null || messageData.length != OFFER_MESSAGE_LENGTH)
+			return null;
+
+		OfferMessageData offerMessageData = new OfferMessageData();
+		offerMessageData.partnerDogecoinPKH = Arrays.copyOfRange(messageData, 0, 20);
+		offerMessageData.hashOfSecretA = Arrays.copyOfRange(messageData, 20, 40);
+		offerMessageData.lockTimeA = BitTwiddling.longFromBEBytes(messageData, 40);
+
+		return offerMessageData;
+	}
+
+	/** Returns 'trade' MESSAGE payload for AT creator to send to AT. */
+	public static byte[] buildTradeMessage(String partnerQortalTradeAddress, byte[] partnerBitcoinPKH, byte[] hashOfSecretA, int lockTimeA, int refundTimeout) {
+		byte[] data = new byte[TRADE_MESSAGE_LENGTH];
+		byte[] partnerQortalAddressBytes = Base58.decode(partnerQortalTradeAddress);
+		byte[] lockTimeABytes = BitTwiddling.toBEByteArray((long) lockTimeA);
+		byte[] refundTimeoutBytes = BitTwiddling.toBEByteArray((long) refundTimeout);
+
+		System.arraycopy(partnerQortalAddressBytes, 0, data, 0, partnerQortalAddressBytes.length);
+		System.arraycopy(partnerBitcoinPKH, 0, data, 32, partnerBitcoinPKH.length);
+		System.arraycopy(refundTimeoutBytes, 0, data, 56, refundTimeoutBytes.length);
+		System.arraycopy(hashOfSecretA, 0, data, 64, hashOfSecretA.length);
+		System.arraycopy(lockTimeABytes, 0, data, 88, lockTimeABytes.length);
+
+		return data;
+	}
+
+	/** Returns 'cancel' MESSAGE payload for AT creator to cancel trade AT. */
+	@Override
+	public byte[] buildCancelMessage(String creatorQortalAddress) {
+		byte[] data = new byte[CANCEL_MESSAGE_LENGTH];
+		byte[] creatorQortalAddressBytes = Base58.decode(creatorQortalAddress);
+
+		System.arraycopy(creatorQortalAddressBytes, 0, data, 0, creatorQortalAddressBytes.length);
+
+		return data;
+	}
+
+	/** Returns 'redeem' MESSAGE payload for trade partner to send to AT. */
+	public static byte[] buildRedeemMessage(byte[] secretA, String qortalReceivingAddress) {
+		byte[] data = new byte[REDEEM_MESSAGE_LENGTH];
+		byte[] qortalReceivingAddressBytes = Base58.decode(qortalReceivingAddress);
+
+		System.arraycopy(secretA, 0, data, 0, secretA.length);
+		System.arraycopy(qortalReceivingAddressBytes, 0, data, 32, qortalReceivingAddressBytes.length);
+
+		return data;
+	}
+
+	/** Returns refund timeout (minutes) based on trade partner's 'offer' MESSAGE timestamp and P2SH-A locktime. */
+	public static int calcRefundTimeout(long offerMessageTimestamp, int lockTimeA) {
+		// refund should be triggered halfway between offerMessageTimestamp and lockTimeA
+		return (int) ((lockTimeA - (offerMessageTimestamp / 1000L)) / 2L / 60L);
+	}
+
+	@Override
+	public byte[] findSecretA(Repository repository, CrossChainTradeData crossChainTradeData) throws DataException {
+		String atAddress = crossChainTradeData.qortalAtAddress;
+		String redeemerAddress = crossChainTradeData.qortalPartnerAddress;
+
+		// We don't have partner's public key so we check every message to AT
+		List<MessageTransactionData> messageTransactionsData = repository.getMessageRepository().getMessagesByParticipants(null, atAddress, null, null, null);
+		if (messageTransactionsData == null)
+			return null;
+
+		// Find 'redeem' message
+		for (MessageTransactionData messageTransactionData : messageTransactionsData) {
+			// Check message payload type/encryption
+			if (messageTransactionData.isText() || messageTransactionData.isEncrypted())
+				continue;
+
+			// Check message payload size
+			byte[] messageData = messageTransactionData.getData();
+			if (messageData.length != REDEEM_MESSAGE_LENGTH)
+				// Wrong payload length
+				continue;
+
+			// Check sender
+			if (!Crypto.toAddress(messageTransactionData.getSenderPublicKey()).equals(redeemerAddress))
+				// Wrong sender;
+				continue;
+
+			// Extract secretA
+			byte[] secretA = new byte[32];
+			System.arraycopy(messageData, 0, secretA, 0, secretA.length);
+
+			byte[] hashOfSecretA = Crypto.hash160(secretA);
+			if (!Arrays.equals(hashOfSecretA, crossChainTradeData.hashOfSecretA))
+				continue;
+
+			return secretA;
+		}
+
+		return null;
+	}
+
+}

src/main/java/org/qortal/crosschain/DogecoinACCTv3.java

@@ -0,0 +1,858 @@
+package org.qortal.crosschain;
+
+import com.google.common.hash.HashCode;
+import com.google.common.primitives.Bytes;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.ciyam.at.*;
+import org.qortal.account.Account;
+import org.qortal.asset.Asset;
+import org.qortal.at.QortalFunctionCode;
+import org.qortal.crypto.Crypto;
+import org.qortal.data.at.ATData;
+import org.qortal.data.at.ATStateData;
+import org.qortal.data.crosschain.CrossChainTradeData;
+import org.qortal.data.transaction.MessageTransactionData;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.utils.Base58;
+import org.qortal.utils.BitTwiddling;
+
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.ciyam.at.OpCode.calcOffset;
+
+/**
+ * Cross-chain trade AT
+ * 
+ * <p>
+ * <ul>
+ * <li>Bob generates Dogecoin & Qortal 'trade' keys
+ * 		<ul>
+ * 			<li>private key required to sign P2SH redeem tx</li>
+ * 			<li>private key could be used to create 'secret' (e.g. double-SHA256)</li>
+ * 			<li>encrypted private key could be stored in Qortal AT for access by Bob from any node</li>
+ * 		</ul>
+ * </li>
+ * <li>Bob deploys Qortal AT
+ * 		<ul>
+ * 		</ul>
+ * </li>
+ * <li>Alice finds Qortal AT and wants to trade
+ * 		<ul>
+ * 			<li>Alice generates Dogecoin & Qortal 'trade' keys</li>
+ * 			<li>Alice funds Dogecoin P2SH-A</li>
+ * 			<li>Alice sends 'offer' MESSAGE to Bob from her Qortal trade address, containing:
+ * 				<ul>
+ * 					<li>hash-of-secret-A</li>
+ * 					<li>her 'trade' Dogecoin PKH</li>
+ * 				</ul>
+ * 			</li>
+ * 		</ul>
+ * </li>
+ * <li>Bob receives "offer" MESSAGE
+ * 		<ul>
+ * 			<li>Checks Alice's P2SH-A</li>
+ * 			<li>Sends 'trade' MESSAGE to Qortal AT from his trade address, containing:
+ * 				<ul>
+ * 					<li>Alice's trade Qortal address</li>
+ * 					<li>Alice's trade Dogecoin PKH</li>
+ * 					<li>hash-of-secret-A</li>
+ * 				</ul>
+ * 			</li>
+ * 		</ul>
+ * </li>
+ * <li>Alice checks Qortal AT to confirm it's locked to her
+ * 		<ul>
+ * 			<li>Alice sends 'redeem' MESSAGE to Qortal AT from her trade address, containing:
+ * 				<ul>
+ * 					<li>secret-A</li>
+ * 					<li>Qortal receiving address of her chosing</li>
+ * 				</ul>
+ * 			</li>
+ * 			<li>AT's QORT funds are sent to Qortal receiving address</li>
+ * 		</ul>
+ * </li>
+ * <li>Bob checks AT, extracts secret-A
+ * 		<ul>
+ * 			<li>Bob redeems P2SH-A using his Dogecoin trade key and secret-A</li>
+ * 			<li>P2SH-A DOGE funds end up at Dogecoin address determined by redeem transaction output(s)</li>
+ * 		</ul>
+ * </li>
+ * </ul>
+ */
+public class DogecoinACCTv3 implements ACCT {
+
+	private static final Logger LOGGER = LogManager.getLogger(DogecoinACCTv3.class);
+
+	public static final String NAME = DogecoinACCTv3.class.getSimpleName();
+	public static final byte[] CODE_BYTES_HASH = HashCode.fromString("03b44087f6325463eb745aa32d9a782add03148bcfbe73ffd8854ce55ff863d4").asBytes(); // SHA256 of AT code bytes
+
+	public static final int SECRET_LENGTH = 32;
+
+	/** <b>Value</b> offset into AT segment where 'mode' variable (long) is stored. (Multiply by MachineState.VALUE_SIZE for byte offset). */
+	private static final int MODE_VALUE_OFFSET = 61;
+	/** <b>Byte</b> offset into AT state data where 'mode' variable (long) is stored. */
+	public static final int MODE_BYTE_OFFSET = MachineState.HEADER_LENGTH + (MODE_VALUE_OFFSET * MachineState.VALUE_SIZE);
+
+	public static class OfferMessageData {
+		public byte[] partnerDogecoinPKH;
+		public byte[] hashOfSecretA;
+		public long lockTimeA;
+	}
+	public static final int OFFER_MESSAGE_LENGTH = 20 /*partnerDogecoinPKH*/ + 20 /*hashOfSecretA*/ + 8 /*lockTimeA*/;
+	public static final int TRADE_MESSAGE_LENGTH = 32 /*partner's Qortal trade address (padded from 25 to 32)*/
+			+ 24 /*partner's Dogecoin PKH (padded from 20 to 24)*/
+			+ 8 /*AT trade timeout (minutes)*/
+			+ 24 /*hash of secret-A (padded from 20 to 24)*/
+			+ 8 /*lockTimeA*/;
+	public static final int REDEEM_MESSAGE_LENGTH = 32 /*secret-A*/ + 32 /*partner's Qortal receiving address padded from 25 to 32*/;
+	public static final int CANCEL_MESSAGE_LENGTH = 32 /*AT creator's Qortal address*/;
+
+	private static DogecoinACCTv3 instance;
+
+	private DogecoinACCTv3() {
+	}
+
+	public static synchronized DogecoinACCTv3 getInstance() {
+		if (instance == null)
+			instance = new DogecoinACCTv3();
+
+		return instance;
+	}
+
+	@Override
+	public byte[] getCodeBytesHash() {
+		return CODE_BYTES_HASH;
+	}
+
+	@Override
+	public int getModeByteOffset() {
+		return MODE_BYTE_OFFSET;
+	}
+
+	@Override
+	public ForeignBlockchain getBlockchain() {
+		return Dogecoin.getInstance();
+	}
+
+	/**
+	 * Returns Qortal AT creation bytes for cross-chain trading AT.
+	 * <p>
+	 * <tt>tradeTimeout</tt> (minutes) is the time window for the trade partner to send the
+	 * 32-byte secret to the AT, before the AT automatically refunds the AT's creator.
+	 * 
+	 * @param creatorTradeAddress AT creator's trade Qortal address
+	 * @param dogecoinPublicKeyHash 20-byte HASH160 of creator's trade Dogecoin public key
+	 * @param qortAmount how much QORT to pay trade partner if they send correct 32-byte secrets to AT
+	 * @param dogecoinAmount how much DOGE the AT creator is expecting to trade
+	 * @param tradeTimeout suggested timeout for entire trade
+	 */
+	public static byte[] buildQortalAT(String creatorTradeAddress, byte[] dogecoinPublicKeyHash, long qortAmount, long dogecoinAmount, int tradeTimeout) {
+		if (dogecoinPublicKeyHash.length != 20)
+			throw new IllegalArgumentException("Dogecoin public key hash should be 20 bytes");
+
+		// Labels for data segment addresses
+		int addrCounter = 0;
+
+		// Constants (with corresponding dataByteBuffer.put*() calls below)
+
+		final int addrCreatorTradeAddress1 = addrCounter++;
+		final int addrCreatorTradeAddress2 = addrCounter++;
+		final int addrCreatorTradeAddress3 = addrCounter++;
+		final int addrCreatorTradeAddress4 = addrCounter++;
+
+		final int addrDogecoinPublicKeyHash = addrCounter;
+		addrCounter += 4;
+
+		final int addrQortAmount = addrCounter++;
+		final int addrDogecoinAmount = addrCounter++;
+		final int addrTradeTimeout = addrCounter++;
+
+		final int addrMessageTxnType = addrCounter++;
+		final int addrExpectedTradeMessageLength = addrCounter++;
+		final int addrExpectedRedeemMessageLength = addrCounter++;
+
+		final int addrCreatorAddressPointer = addrCounter++;
+		final int addrQortalPartnerAddressPointer = addrCounter++;
+		final int addrMessageSenderPointer = addrCounter++;
+
+		final int addrTradeMessagePartnerDogecoinPKHOffset = addrCounter++;
+		final int addrPartnerDogecoinPKHPointer = addrCounter++;
+		final int addrTradeMessageHashOfSecretAOffset = addrCounter++;
+		final int addrHashOfSecretAPointer = addrCounter++;
+
+		final int addrRedeemMessageReceivingAddressOffset = addrCounter++;
+
+		final int addrMessageDataPointer = addrCounter++;
+		final int addrMessageDataLength = addrCounter++;
+
+		final int addrPartnerReceivingAddressPointer = addrCounter++;
+
+		final int addrEndOfConstants = addrCounter;
+
+		// Variables
+
+		final int addrCreatorAddress1 = addrCounter++;
+		final int addrCreatorAddress2 = addrCounter++;
+		final int addrCreatorAddress3 = addrCounter++;
+		final int addrCreatorAddress4 = addrCounter++;
+
+		final int addrQortalPartnerAddress1 = addrCounter++;
+		final int addrQortalPartnerAddress2 = addrCounter++;
+		final int addrQortalPartnerAddress3 = addrCounter++;
+		final int addrQortalPartnerAddress4 = addrCounter++;
+
+		final int addrLockTimeA = addrCounter++;
+		final int addrRefundTimeout = addrCounter++;
+		final int addrRefundTimestamp = addrCounter++;
+		final int addrLastTxnTimestamp = addrCounter++;
+		final int addrBlockTimestamp = addrCounter++;
+		final int addrTxnType = addrCounter++;
+		final int addrResult = addrCounter++;
+
+		final int addrMessageSender1 = addrCounter++;
+		final int addrMessageSender2 = addrCounter++;
+		final int addrMessageSender3 = addrCounter++;
+		final int addrMessageSender4 = addrCounter++;
+
+		final int addrMessageLength = addrCounter++;
+
+		final int addrMessageData = addrCounter;
+		addrCounter += 4;
+
+		final int addrHashOfSecretA = addrCounter;
+		addrCounter += 4;
+
+		final int addrPartnerDogecoinPKH = addrCounter;
+		addrCounter += 4;
+
+		final int addrPartnerReceivingAddress = addrCounter;
+		addrCounter += 4;
+
+		final int addrMode = addrCounter++;
+		assert addrMode == MODE_VALUE_OFFSET : String.format("addrMode %d does not match MODE_VALUE_OFFSET %d", addrMode, MODE_VALUE_OFFSET);
+
+		// Data segment
+		ByteBuffer dataByteBuffer = ByteBuffer.allocate(addrCounter * MachineState.VALUE_SIZE);
+
+		// AT creator's trade Qortal address, decoded from Base58
+		assert dataByteBuffer.position() == addrCreatorTradeAddress1 * MachineState.VALUE_SIZE : "addrCreatorTradeAddress1 incorrect";
+		byte[] creatorTradeAddressBytes = Base58.decode(creatorTradeAddress);
+		dataByteBuffer.put(Bytes.ensureCapacity(creatorTradeAddressBytes, 32, 0));
+
+		// Dogecoin public key hash
+		assert dataByteBuffer.position() == addrDogecoinPublicKeyHash * MachineState.VALUE_SIZE : "addrDogecoinPublicKeyHash incorrect";
+		dataByteBuffer.put(Bytes.ensureCapacity(dogecoinPublicKeyHash, 32, 0));
+
+		// Redeem Qort amount
+		assert dataByteBuffer.position() == addrQortAmount * MachineState.VALUE_SIZE : "addrQortAmount incorrect";
+		dataByteBuffer.putLong(qortAmount);
+
+		// Expected Dogecoin amount
+		assert dataByteBuffer.position() == addrDogecoinAmount * MachineState.VALUE_SIZE : "addrDogecoinAmount incorrect";
+		dataByteBuffer.putLong(dogecoinAmount);
+
+		// Suggested trade timeout (minutes)
+		assert dataByteBuffer.position() == addrTradeTimeout * MachineState.VALUE_SIZE : "addrTradeTimeout incorrect";
+		dataByteBuffer.putLong(tradeTimeout);
+
+		// We're only interested in MESSAGE transactions
+		assert dataByteBuffer.position() == addrMessageTxnType * MachineState.VALUE_SIZE : "addrMessageTxnType incorrect";
+		dataByteBuffer.putLong(API.ATTransactionType.MESSAGE.value);
+
+		// Expected length of 'trade' MESSAGE data from AT creator
+		assert dataByteBuffer.position() == addrExpectedTradeMessageLength * MachineState.VALUE_SIZE : "addrExpectedTradeMessageLength incorrect";
+		dataByteBuffer.putLong(TRADE_MESSAGE_LENGTH);
+
+		// Expected length of 'redeem' MESSAGE data from trade partner
+		assert dataByteBuffer.position() == addrExpectedRedeemMessageLength * MachineState.VALUE_SIZE : "addrExpectedRedeemMessageLength incorrect";
+		dataByteBuffer.putLong(REDEEM_MESSAGE_LENGTH);
+
+		// Index into data segment of AT creator's address, used by GET_B_IND
+		assert dataByteBuffer.position() == addrCreatorAddressPointer * MachineState.VALUE_SIZE : "addrCreatorAddressPointer incorrect";
+		dataByteBuffer.putLong(addrCreatorAddress1);
+
+		// Index into data segment of partner's Qortal address, used by SET_B_IND
+		assert dataByteBuffer.position() == addrQortalPartnerAddressPointer * MachineState.VALUE_SIZE : "addrQortalPartnerAddressPointer incorrect";
+		dataByteBuffer.putLong(addrQortalPartnerAddress1);
+
+		// Index into data segment of (temporary) transaction's sender's address, used by GET_B_IND
+		assert dataByteBuffer.position() == addrMessageSenderPointer * MachineState.VALUE_SIZE : "addrMessageSenderPointer incorrect";
+		dataByteBuffer.putLong(addrMessageSender1);
+
+		// Offset into 'trade' MESSAGE data payload for extracting partner's Dogecoin PKH
+		assert dataByteBuffer.position() == addrTradeMessagePartnerDogecoinPKHOffset * MachineState.VALUE_SIZE : "addrTradeMessagePartnerDogecoinPKHOffset incorrect";
+		dataByteBuffer.putLong(32L);
+
+		// Index into data segment of partner's Dogecoin PKH, used by GET_B_IND
+		assert dataByteBuffer.position() == addrPartnerDogecoinPKHPointer * MachineState.VALUE_SIZE : "addrPartnerDogecoinPKHPointer incorrect";
+		dataByteBuffer.putLong(addrPartnerDogecoinPKH);
+
+		// Offset into 'trade' MESSAGE data payload for extracting hash-of-secret-A
+		assert dataByteBuffer.position() == addrTradeMessageHashOfSecretAOffset * MachineState.VALUE_SIZE : "addrTradeMessageHashOfSecretAOffset incorrect";
+		dataByteBuffer.putLong(64L);
+
+		// Index into data segment to hash of secret A, used by GET_B_IND
+		assert dataByteBuffer.position() == addrHashOfSecretAPointer * MachineState.VALUE_SIZE : "addrHashOfSecretAPointer incorrect";
+		dataByteBuffer.putLong(addrHashOfSecretA);
+
+		// Offset into 'redeem' MESSAGE data payload for extracting Qortal receiving address
+		assert dataByteBuffer.position() == addrRedeemMessageReceivingAddressOffset * MachineState.VALUE_SIZE : "addrRedeemMessageReceivingAddressOffset incorrect";
+		dataByteBuffer.putLong(32L);
+
+		// Source location and length for hashing any passed secret
+		assert dataByteBuffer.position() == addrMessageDataPointer * MachineState.VALUE_SIZE : "addrMessageDataPointer incorrect";
+		dataByteBuffer.putLong(addrMessageData);
+		assert dataByteBuffer.position() == addrMessageDataLength * MachineState.VALUE_SIZE : "addrMessageDataLength incorrect";
+		dataByteBuffer.putLong(32L);
+
+		// Pointer into data segment of where to save partner's receiving Qortal address, used by GET_B_IND
+		assert dataByteBuffer.position() == addrPartnerReceivingAddressPointer * MachineState.VALUE_SIZE : "addrPartnerReceivingAddressPointer incorrect";
+		dataByteBuffer.putLong(addrPartnerReceivingAddress);
+
+		assert dataByteBuffer.position() == addrEndOfConstants * MachineState.VALUE_SIZE : "dataByteBuffer position not at end of constants";
+
+		// Code labels
+		Integer labelRefund = null;
+
+		Integer labelTradeTxnLoop = null;
+		Integer labelCheckTradeTxn = null;
+		Integer labelCheckCancelTxn = null;
+		Integer labelNotTradeNorCancelTxn = null;
+		Integer labelCheckNonRefundTradeTxn = null;
+		Integer labelTradeTxnExtract = null;
+		Integer labelRedeemTxnLoop = null;
+		Integer labelCheckRedeemTxn = null;
+		Integer labelCheckRedeemTxnSender = null;
+		Integer labelPayout = null;
+
+		ByteBuffer codeByteBuffer = ByteBuffer.allocate(768);
+
+		// Two-pass version
+		for (int pass = 0; pass < 2; ++pass) {
+			codeByteBuffer.clear();
+
+			try {
+				/* Initialization */
+
+				/* NOP - to ensure DOGECOIN ACCT is unique */
+				codeByteBuffer.put(OpCode.NOP.compile());
+
+				// Use AT creation 'timestamp' as starting point for finding transactions sent to AT
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_CREATION_TIMESTAMP, addrLastTxnTimestamp));
+
+				// Load B register with AT creator's address so we can save it into addrCreatorAddress1-4
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_CREATOR_INTO_B));
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrCreatorAddressPointer));
+
+				// Set restart position to after this opcode
+				codeByteBuffer.put(OpCode.SET_PCS.compile());
+
+				/* Loop, waiting for message from AT creator's trade address containing trade partner details, or AT owner's address to cancel offer */
+
+				/* Transaction processing loop */
+				labelTradeTxnLoop = codeByteBuffer.position();
+
+				/* Sleep until message arrives */
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.SLEEP_UNTIL_MESSAGE.value, addrLastTxnTimestamp));
+
+				// Find next transaction (if any) to this AT since the last one (referenced by addrLastTxnTimestamp)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PUT_TX_AFTER_TIMESTAMP_INTO_A, addrLastTxnTimestamp));
+				// If no transaction found, A will be zero. If A is zero, set addrResult to 1, otherwise 0.
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.CHECK_A_IS_ZERO, addrResult));
+				// If addrResult is zero (i.e. A is non-zero, transaction was found) then go check transaction
+				codeByteBuffer.put(OpCode.BZR_DAT.compile(addrResult, calcOffset(codeByteBuffer, labelCheckTradeTxn)));
+				// Stop and wait for next block
+				codeByteBuffer.put(OpCode.STP_IMD.compile());
+
+				/* Check transaction */
+				labelCheckTradeTxn = codeByteBuffer.position();
+
+				// Update our 'last found transaction's timestamp' using 'timestamp' from transaction
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TIMESTAMP_FROM_TX_IN_A, addrLastTxnTimestamp));
+				// Extract transaction type (message/payment) from transaction and save type in addrTxnType
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TYPE_FROM_TX_IN_A, addrTxnType));
+				// If transaction type is not MESSAGE type then go look for another transaction
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrTxnType, addrMessageTxnType, calcOffset(codeByteBuffer, labelTradeTxnLoop)));
+
+				/* Check transaction's sender. We're expecting AT creator's trade address for 'trade' message, or AT creator's own address for 'cancel' message. */
+
+				// Extract sender address from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_ADDRESS_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrMessageSender1 (as pointed to by addrMessageSenderPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrMessageSenderPointer));
+				// Compare each part of message sender's address with AT creator's trade address. If they don't match, check for cancel situation.
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender1, addrCreatorTradeAddress1, calcOffset(codeByteBuffer, labelCheckCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender2, addrCreatorTradeAddress2, calcOffset(codeByteBuffer, labelCheckCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender3, addrCreatorTradeAddress3, calcOffset(codeByteBuffer, labelCheckCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender4, addrCreatorTradeAddress4, calcOffset(codeByteBuffer, labelCheckCancelTxn)));
+				// Message sender's address matches AT creator's trade address so go process 'trade' message
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelCheckNonRefundTradeTxn == null ? 0 : labelCheckNonRefundTradeTxn));
+
+				/* Checking message sender for possible cancel message */
+				labelCheckCancelTxn = codeByteBuffer.position();
+
+				// Compare each part of message sender's address with AT creator's address. If they don't match, look for another transaction.
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender1, addrCreatorAddress1, calcOffset(codeByteBuffer, labelNotTradeNorCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender2, addrCreatorAddress2, calcOffset(codeByteBuffer, labelNotTradeNorCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender3, addrCreatorAddress3, calcOffset(codeByteBuffer, labelNotTradeNorCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender4, addrCreatorAddress4, calcOffset(codeByteBuffer, labelNotTradeNorCancelTxn)));
+				// Partner address is AT creator's address, so cancel offer and finish.
+				codeByteBuffer.put(OpCode.SET_VAL.compile(addrMode, AcctMode.CANCELLED.value));
+				// We're finished forever (finishing auto-refunds remaining balance to AT creator)
+				codeByteBuffer.put(OpCode.FIN_IMD.compile());
+
+				/* Not trade nor cancel message */
+				labelNotTradeNorCancelTxn = codeByteBuffer.position();
+
+				// Loop to find another transaction
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelTradeTxnLoop == null ? 0 : labelTradeTxnLoop));
+
+				/* Possible switch-to-trade-mode message */
+				labelCheckNonRefundTradeTxn = codeByteBuffer.position();
+
+				// Check 'trade' message we received has expected number of message bytes
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(QortalFunctionCode.GET_MESSAGE_LENGTH_FROM_TX_IN_A.value, addrMessageLength));
+				// If message length matches, branch to info extraction code
+				codeByteBuffer.put(OpCode.BEQ_DAT.compile(addrMessageLength, addrExpectedTradeMessageLength, calcOffset(codeByteBuffer, labelTradeTxnExtract)));
+				// Message length didn't match - go back to finding another 'trade' MESSAGE transaction
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelTradeTxnLoop == null ? 0 : labelTradeTxnLoop));
+
+				/* Extracting info from 'trade' MESSAGE transaction */
+				labelTradeTxnExtract = codeByteBuffer.position();
+
+				// Extract message from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_MESSAGE_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrQortalPartnerAddress1 (as pointed to by addrQortalPartnerAddressPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrQortalPartnerAddressPointer));
+
+				// Extract trade partner's Dogecoin public key hash (PKH) from message into B
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.PUT_PARTIAL_MESSAGE_FROM_TX_IN_A_INTO_B.value, addrTradeMessagePartnerDogecoinPKHOffset));
+				// Store partner's Dogecoin PKH (we only really use values from B1-B3)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrPartnerDogecoinPKHPointer));
+				// Extract AT trade timeout (minutes) (from B4)
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_B4, addrRefundTimeout));
+
+				// Grab next 32 bytes
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.PUT_PARTIAL_MESSAGE_FROM_TX_IN_A_INTO_B.value, addrTradeMessageHashOfSecretAOffset));
+
+				// Extract hash-of-secret-A (we only really use values from B1-B3)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrHashOfSecretAPointer));
+				// Extract lockTime-A (from B4)
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_B4, addrLockTimeA));
+
+				// Calculate trade timeout refund 'timestamp' by adding addrRefundTimeout minutes to this transaction's 'timestamp', then save into addrRefundTimestamp
+				codeByteBuffer.put(OpCode.EXT_FUN_RET_DAT_2.compile(FunctionCode.ADD_MINUTES_TO_TIMESTAMP, addrRefundTimestamp, addrLastTxnTimestamp, addrRefundTimeout));
+
+				/* We are in 'trade mode' */
+				codeByteBuffer.put(OpCode.SET_VAL.compile(addrMode, AcctMode.TRADING.value));
+
+				// Set restart position to after this opcode
+				codeByteBuffer.put(OpCode.SET_PCS.compile());
+
+				/* Loop, waiting for trade timeout or 'redeem' MESSAGE from Qortal trade partner */
+
+				// Fetch current block 'timestamp'
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_BLOCK_TIMESTAMP, addrBlockTimestamp));
+				// If we're not past refund 'timestamp' then look for next transaction
+				codeByteBuffer.put(OpCode.BLT_DAT.compile(addrBlockTimestamp, addrRefundTimestamp, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+				// We're past refund 'timestamp' so go refund everything back to AT creator
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelRefund == null ? 0 : labelRefund));
+
+				/* Transaction processing loop */
+				labelRedeemTxnLoop = codeByteBuffer.position();
+
+				// Find next transaction to this AT since the last one (if any)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PUT_TX_AFTER_TIMESTAMP_INTO_A, addrLastTxnTimestamp));
+				// If no transaction found, A will be zero. If A is zero, set addrComparator to 1, otherwise 0.
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.CHECK_A_IS_ZERO, addrResult));
+				// If addrResult is zero (i.e. A is non-zero, transaction was found) then go check transaction
+				codeByteBuffer.put(OpCode.BZR_DAT.compile(addrResult, calcOffset(codeByteBuffer, labelCheckRedeemTxn)));
+				// Stop and wait for next block
+				codeByteBuffer.put(OpCode.STP_IMD.compile());
+
+				/* Check transaction */
+				labelCheckRedeemTxn = codeByteBuffer.position();
+
+				// Update our 'last found transaction's timestamp' using 'timestamp' from transaction
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TIMESTAMP_FROM_TX_IN_A, addrLastTxnTimestamp));
+				// Extract transaction type (message/payment) from transaction and save type in addrTxnType
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TYPE_FROM_TX_IN_A, addrTxnType));
+				// If transaction type is not MESSAGE type then go look for another transaction
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrTxnType, addrMessageTxnType, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+
+				/* Check message payload length */
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(QortalFunctionCode.GET_MESSAGE_LENGTH_FROM_TX_IN_A.value, addrMessageLength));
+				// If message length matches, branch to sender checking code
+				codeByteBuffer.put(OpCode.BEQ_DAT.compile(addrMessageLength, addrExpectedRedeemMessageLength, calcOffset(codeByteBuffer, labelCheckRedeemTxnSender)));
+				// Message length didn't match - go back to finding another 'redeem' MESSAGE transaction
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelRedeemTxnLoop == null ? 0 : labelRedeemTxnLoop));
+
+				/* Check transaction's sender */
+				labelCheckRedeemTxnSender = codeByteBuffer.position();
+
+				// Extract sender address from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_ADDRESS_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrMessageSender1 (as pointed to by addrMessageSenderPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrMessageSenderPointer));
+				// Compare each part of transaction's sender's address with expected address. If they don't match, look for another transaction.
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender1, addrQortalPartnerAddress1, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender2, addrQortalPartnerAddress2, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender3, addrQortalPartnerAddress3, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender4, addrQortalPartnerAddress4, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+
+				/* Check 'secret-A' in transaction's message */
+
+				// Extract secret-A from first 32 bytes of message from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_MESSAGE_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrMessageData (as pointed to by addrMessageDataPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrMessageDataPointer));
+				// Load B register with expected hash result (as pointed to by addrHashOfSecretAPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.SET_B_IND, addrHashOfSecretAPointer));
+				// Perform HASH160 using source data at addrMessageData. (Location and length specified via addrMessageDataPointer and addrMessageDataLength).
+				// Save the equality result (1 if they match, 0 otherwise) into addrResult.
+				codeByteBuffer.put(OpCode.EXT_FUN_RET_DAT_2.compile(FunctionCode.CHECK_HASH160_WITH_B, addrResult, addrMessageDataPointer, addrMessageDataLength));
+				// If hashes don't match, addrResult will be zero so go find another transaction
+				codeByteBuffer.put(OpCode.BNZ_DAT.compile(addrResult, calcOffset(codeByteBuffer, labelPayout)));
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelRedeemTxnLoop == null ? 0 : labelRedeemTxnLoop));
+
+				/* Success! Pay arranged amount to receiving address */
+				labelPayout = codeByteBuffer.position();
+
+				// Extract Qortal receiving address from next 32 bytes of message from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.PUT_PARTIAL_MESSAGE_FROM_TX_IN_A_INTO_B.value, addrRedeemMessageReceivingAddressOffset));
+				// Save B register into data segment starting at addrPartnerReceivingAddress (as pointed to by addrPartnerReceivingAddressPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrPartnerReceivingAddressPointer));
+				// Pay AT's balance to receiving address
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PAY_TO_ADDRESS_IN_B, addrQortAmount));
+				// Set redeemed mode
+				codeByteBuffer.put(OpCode.SET_VAL.compile(addrMode, AcctMode.REDEEMED.value));
+				// We're finished forever (finishing auto-refunds remaining balance to AT creator)
+				codeByteBuffer.put(OpCode.FIN_IMD.compile());
+
+				// Fall-through to refunding any remaining balance back to AT creator
+
+				/* Refund balance back to AT creator */
+				labelRefund = codeByteBuffer.position();
+
+				// Set refunded mode
+				codeByteBuffer.put(OpCode.SET_VAL.compile(addrMode, AcctMode.REFUNDED.value));
+				// We're finished forever (finishing auto-refunds remaining balance to AT creator)
+				codeByteBuffer.put(OpCode.FIN_IMD.compile());
+			} catch (CompilationException e) {
+				throw new IllegalStateException("Unable to compile DOGE-QORT ACCT?", e);
+			}
+		}
+
+		codeByteBuffer.flip();
+
+		byte[] codeBytes = new byte[codeByteBuffer.limit()];
+		codeByteBuffer.get(codeBytes);
+
+		assert Arrays.equals(Crypto.digest(codeBytes), DogecoinACCTv3.CODE_BYTES_HASH)
+			: String.format("BTCACCT.CODE_BYTES_HASH mismatch: expected %s, actual %s", HashCode.fromBytes(CODE_BYTES_HASH), HashCode.fromBytes(Crypto.digest(codeBytes)));
+
+		final short ciyamAtVersion = 2;
+		final short numCallStackPages = 0;
+		final short numUserStackPages = 0;
+		final long minActivationAmount = 0L;
+
+		return MachineState.toCreationBytes(ciyamAtVersion, codeBytes, dataByteBuffer.array(), numCallStackPages, numUserStackPages, minActivationAmount);
+	}
+
+	/**
+	 * Returns CrossChainTradeData with useful info extracted from AT.
+	 */
+	@Override
+	public CrossChainTradeData populateTradeData(Repository repository, ATData atData) throws DataException {
+		ATStateData atStateData = repository.getATRepository().getLatestATState(atData.getATAddress());
+		return populateTradeData(repository, atData.getCreatorPublicKey(), atData.getCreation(), atStateData);
+	}
+
+	/**
+	 * Returns CrossChainTradeData with useful info extracted from AT.
+	 */
+	@Override
+	public CrossChainTradeData populateTradeData(Repository repository, ATStateData atStateData) throws DataException {
+		ATData atData = repository.getATRepository().fromATAddress(atStateData.getATAddress());
+		return populateTradeData(repository, atData.getCreatorPublicKey(), atData.getCreation(), atStateData);
+	}
+
+	/**
+	 * Returns CrossChainTradeData with useful info extracted from AT.
+	 */
+	public CrossChainTradeData populateTradeData(Repository repository, byte[] creatorPublicKey, long creationTimestamp, ATStateData atStateData) throws DataException {
+		byte[] addressBytes = new byte[25]; // for general use
+		String atAddress = atStateData.getATAddress();
+
+		CrossChainTradeData tradeData = new CrossChainTradeData();
+
+		tradeData.foreignBlockchain = SupportedBlockchain.DOGECOIN.name();
+		tradeData.acctName = NAME;
+
+		tradeData.qortalAtAddress = atAddress;
+		tradeData.qortalCreator = Crypto.toAddress(creatorPublicKey);
+		tradeData.creationTimestamp = creationTimestamp;
+
+		Account atAccount = new Account(repository, atAddress);
+		tradeData.qortBalance = atAccount.getConfirmedBalance(Asset.QORT);
+
+		byte[] stateData = atStateData.getStateData();
+		ByteBuffer dataByteBuffer = ByteBuffer.wrap(stateData);
+		dataByteBuffer.position(MachineState.HEADER_LENGTH);
+
+		/* Constants */
+
+		// Skip creator's trade address
+		dataByteBuffer.get(addressBytes);
+		tradeData.qortalCreatorTradeAddress = Base58.encode(addressBytes);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - addressBytes.length);
+
+		// Creator's Dogecoin/foreign public key hash
+		tradeData.creatorForeignPKH = new byte[20];
+		dataByteBuffer.get(tradeData.creatorForeignPKH);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - tradeData.creatorForeignPKH.length); // skip to 32 bytes
+
+		// We don't use secret-B
+		tradeData.hashOfSecretB = null;
+
+		// Redeem payout
+		tradeData.qortAmount = dataByteBuffer.getLong();
+
+		// Expected DOGE amount
+		tradeData.expectedForeignAmount = dataByteBuffer.getLong();
+
+		// Trade timeout
+		tradeData.tradeTimeout = (int) dataByteBuffer.getLong();
+
+		// Skip MESSAGE transaction type
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip expected 'trade' message length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip expected 'redeem' message length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to creator's address
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to partner's Qortal trade address
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to message sender
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip 'trade' message data offset for partner's Dogecoin PKH
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to partner's Dogecoin PKH
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip 'trade' message data offset for hash-of-secret-A
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to hash-of-secret-A
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip 'redeem' message data offset for partner's Qortal receiving address
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to message data
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip message data length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to partner's receiving address
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		/* End of constants / begin variables */
+
+		// Skip AT creator's address
+		dataByteBuffer.position(dataByteBuffer.position() + 8 * 4);
+
+		// Partner's trade address (if present)
+		dataByteBuffer.get(addressBytes);
+		String qortalRecipient = Base58.encode(addressBytes);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - addressBytes.length);
+
+		// Potential lockTimeA (if in trade mode)
+		int lockTimeA = (int) dataByteBuffer.getLong();
+
+		// AT refund timeout (probably only useful for debugging)
+		int refundTimeout = (int) dataByteBuffer.getLong();
+
+		// Trade-mode refund timestamp (AT 'timestamp' converted to Qortal block height)
+		long tradeRefundTimestamp = dataByteBuffer.getLong();
+
+		// Skip last transaction timestamp
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip block timestamp
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip transaction type
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip temporary result
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip temporary message sender
+		dataByteBuffer.position(dataByteBuffer.position() + 8 * 4);
+
+		// Skip message length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip temporary message data
+		dataByteBuffer.position(dataByteBuffer.position() + 8 * 4);
+
+		// Potential hash160 of secret A
+		byte[] hashOfSecretA = new byte[20];
+		dataByteBuffer.get(hashOfSecretA);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - hashOfSecretA.length); // skip to 32 bytes
+
+		// Potential partner's Dogecoin PKH
+		byte[] partnerDogecoinPKH = new byte[20];
+		dataByteBuffer.get(partnerDogecoinPKH);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - partnerDogecoinPKH.length); // skip to 32 bytes
+
+		// Partner's receiving address (if present)
+		byte[] partnerReceivingAddress = new byte[25];
+		dataByteBuffer.get(partnerReceivingAddress);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - partnerReceivingAddress.length); // skip to 32 bytes
+
+		// Trade AT's 'mode'
+		long modeValue = dataByteBuffer.getLong();
+		AcctMode mode = AcctMode.valueOf((int) (modeValue & 0xffL));
+
+		/* End of variables */
+
+		if (mode != null && mode != AcctMode.OFFERING) {
+			tradeData.mode = mode;
+			tradeData.refundTimeout = refundTimeout;
+			tradeData.tradeRefundHeight = new Timestamp(tradeRefundTimestamp).blockHeight;
+			tradeData.qortalPartnerAddress = qortalRecipient;
+			tradeData.hashOfSecretA = hashOfSecretA;
+			tradeData.partnerForeignPKH = partnerDogecoinPKH;
+			tradeData.lockTimeA = lockTimeA;
+
+			if (mode == AcctMode.REDEEMED)
+				tradeData.qortalPartnerReceivingAddress = Base58.encode(partnerReceivingAddress);
+		} else {
+			tradeData.mode = AcctMode.OFFERING;
+		}
+
+		tradeData.duplicateDeprecated();
+
+		return tradeData;
+	}
+
+	/** Returns 'offer' MESSAGE payload for trade partner to send to AT creator's trade address. */
+	public static byte[] buildOfferMessage(byte[] partnerBitcoinPKH, byte[] hashOfSecretA, int lockTimeA) {
+		byte[] lockTimeABytes = BitTwiddling.toBEByteArray((long) lockTimeA);
+		return Bytes.concat(partnerBitcoinPKH, hashOfSecretA, lockTimeABytes);
+	}
+
+	/** Returns info extracted from 'offer' MESSAGE payload sent by trade partner to AT creator's trade address, or null if not valid. */
+	public static OfferMessageData extractOfferMessageData(byte[] messageData) {
+		if (messageData == null || messageData.length != OFFER_MESSAGE_LENGTH)
+			return null;
+
+		OfferMessageData offerMessageData = new OfferMessageData();
+		offerMessageData.partnerDogecoinPKH = Arrays.copyOfRange(messageData, 0, 20);
+		offerMessageData.hashOfSecretA = Arrays.copyOfRange(messageData, 20, 40);
+		offerMessageData.lockTimeA = BitTwiddling.longFromBEBytes(messageData, 40);
+
+		return offerMessageData;
+	}
+
+	/** Returns 'trade' MESSAGE payload for AT creator to send to AT. */
+	public static byte[] buildTradeMessage(String partnerQortalTradeAddress, byte[] partnerBitcoinPKH, byte[] hashOfSecretA, int lockTimeA, int refundTimeout) {
+		byte[] data = new byte[TRADE_MESSAGE_LENGTH];
+		byte[] partnerQortalAddressBytes = Base58.decode(partnerQortalTradeAddress);
+		byte[] lockTimeABytes = BitTwiddling.toBEByteArray((long) lockTimeA);
+		byte[] refundTimeoutBytes = BitTwiddling.toBEByteArray((long) refundTimeout);
+
+		System.arraycopy(partnerQortalAddressBytes, 0, data, 0, partnerQortalAddressBytes.length);
+		System.arraycopy(partnerBitcoinPKH, 0, data, 32, partnerBitcoinPKH.length);
+		System.arraycopy(refundTimeoutBytes, 0, data, 56, refundTimeoutBytes.length);
+		System.arraycopy(hashOfSecretA, 0, data, 64, hashOfSecretA.length);
+		System.arraycopy(lockTimeABytes, 0, data, 88, lockTimeABytes.length);
+
+		return data;
+	}
+
+	/** Returns 'cancel' MESSAGE payload for AT creator to cancel trade AT. */
+	@Override
+	public byte[] buildCancelMessage(String creatorQortalAddress) {
+		byte[] data = new byte[CANCEL_MESSAGE_LENGTH];
+		byte[] creatorQortalAddressBytes = Base58.decode(creatorQortalAddress);
+
+		System.arraycopy(creatorQortalAddressBytes, 0, data, 0, creatorQortalAddressBytes.length);
+
+		return data;
+	}
+
+	/** Returns 'redeem' MESSAGE payload for trade partner to send to AT. */
+	public static byte[] buildRedeemMessage(byte[] secretA, String qortalReceivingAddress) {
+		byte[] data = new byte[REDEEM_MESSAGE_LENGTH];
+		byte[] qortalReceivingAddressBytes = Base58.decode(qortalReceivingAddress);
+
+		System.arraycopy(secretA, 0, data, 0, secretA.length);
+		System.arraycopy(qortalReceivingAddressBytes, 0, data, 32, qortalReceivingAddressBytes.length);
+
+		return data;
+	}
+
+	/** Returns refund timeout (minutes) based on trade partner's 'offer' MESSAGE timestamp and P2SH-A locktime. */
+	public static int calcRefundTimeout(long offerMessageTimestamp, int lockTimeA) {
+		// refund should be triggered halfway between offerMessageTimestamp and lockTimeA
+		return (int) ((lockTimeA - (offerMessageTimestamp / 1000L)) / 2L / 60L);
+	}
+
+	@Override
+	public byte[] findSecretA(Repository repository, CrossChainTradeData crossChainTradeData) throws DataException {
+		String atAddress = crossChainTradeData.qortalAtAddress;
+		String redeemerAddress = crossChainTradeData.qortalPartnerAddress;
+
+		// We don't have partner's public key so we check every message to AT
+		List<MessageTransactionData> messageTransactionsData = repository.getMessageRepository().getMessagesByParticipants(null, atAddress, null, null, null);
+		if (messageTransactionsData == null)
+			return null;
+
+		// Find 'redeem' message
+		for (MessageTransactionData messageTransactionData : messageTransactionsData) {
+			// Check message payload type/encryption
+			if (messageTransactionData.isText() || messageTransactionData.isEncrypted())
+				continue;
+
+			// Check message payload size
+			byte[] messageData = messageTransactionData.getData();
+			if (messageData.length != REDEEM_MESSAGE_LENGTH)
+				// Wrong payload length
+				continue;
+
+			// Check sender
+			if (!Crypto.toAddress(messageTransactionData.getSenderPublicKey()).equals(redeemerAddress))
+				// Wrong sender;
+				continue;
+
+			// Extract secretA
+			byte[] secretA = new byte[32];
+			System.arraycopy(messageData, 0, secretA, 0, secretA.length);
+
+			byte[] hashOfSecretA = Crypto.hash160(secretA);
+			if (!Arrays.equals(hashOfSecretA, crossChainTradeData.hashOfSecretA))
+				continue;
+
+			return secretA;
+		}
+
+		return null;
+	}
+
+}

src/main/java/org/qortal/crosschain/ElectrumX.java

@@ -653,18 +653,27 @@ public class ElectrumX extends BitcoinyBlockchainProvider {
 
 		Object errorObj = responseJson.get("error");
 		if (errorObj != null) {
-			if (errorObj instanceof String)
-				throw new ForeignBlockchainException.NetworkException(String.format("Unexpected error message from ElectrumX RPC %s: %s", method, (String) errorObj), this.currentServer);
+			if (errorObj instanceof String) {
+				LOGGER.debug(String.format("Unexpected error message from ElectrumX server %s for RPC method %s: %s", this.currentServer, method, (String) errorObj));
+				// Try another server
+				return null;
+			}
 
-			if (!(errorObj instanceof JSONObject))
-				throw new ForeignBlockchainException.NetworkException(String.format("Unexpected error response from ElectrumX RPC %s", method), this.currentServer);
+			if (!(errorObj instanceof JSONObject)) {
+				LOGGER.debug(String.format("Unexpected error response from ElectrumX server %s for RPC method %s", this.currentServer, method));
+				// Try another server
+				return null;
+			}
 
 			JSONObject errorJson = (JSONObject) errorObj;
 
 			Object messageObj = errorJson.get("message");
 
-			if (!(messageObj instanceof String))
-				throw new ForeignBlockchainException.NetworkException(String.format("Missing/invalid message in error response from ElectrumX RPC %s", method), this.currentServer);
+			if (!(messageObj instanceof String)) {
+				LOGGER.debug(String.format("Missing/invalid message in error response from ElectrumX server %s for RPC method %s", this.currentServer, method));
+				// Try another server
+				return null;
+			}
 
 			String message = (String) messageObj;
 

src/main/java/org/qortal/crosschain/Litecoin.java

@@ -21,6 +21,8 @@ public class Litecoin extends Bitcoiny {
 
 	private static final Coin DEFAULT_FEE_PER_KB = Coin.valueOf(10000); // 0.0001 LTC per 1000 bytes
 
+	private static final long MINIMUM_ORDER_AMOUNT = 1000000; // 0.01 LTC minimum order, to avoid dust errors
+
 	// Temporary values until a dynamic fee system is written.
 	private static final long MAINNET_FEE = 1000L;
 	private static final long NON_MAINNET_FEE = 1000L; // enough for TESTNET3 and should be OK for REGTEST
@@ -164,6 +166,11 @@ public class Litecoin extends Bitcoiny {
 		return DEFAULT_FEE_PER_KB;
 	}
 
+	@Override
+	public long getMinimumOrderAmount() {
+		return MINIMUM_ORDER_AMOUNT;
+	}
+
 	/**
 	 * Returns estimated LTC fee, in sats per 1000bytes, optionally for historic timestamp.
 	 * 

src/main/java/org/qortal/crosschain/LitecoinACCTv2.java

@@ -0,0 +1,854 @@
+package org.qortal.crosschain;
+
+import com.google.common.hash.HashCode;
+import com.google.common.primitives.Bytes;
+import org.ciyam.at.*;
+import org.qortal.account.Account;
+import org.qortal.asset.Asset;
+import org.qortal.at.QortalFunctionCode;
+import org.qortal.crypto.Crypto;
+import org.qortal.data.at.ATData;
+import org.qortal.data.at.ATStateData;
+import org.qortal.data.crosschain.CrossChainTradeData;
+import org.qortal.data.transaction.MessageTransactionData;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.utils.Base58;
+import org.qortal.utils.BitTwiddling;
+
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.ciyam.at.OpCode.calcOffset;
+
+/**
+ * Cross-chain trade AT
+ * 
+ * <p>
+ * <ul>
+ * <li>Bob generates Litecoin & Qortal 'trade' keys
+ * 		<ul>
+ * 			<li>private key required to sign P2SH redeem tx</li>
+ * 			<li>private key could be used to create 'secret' (e.g. double-SHA256)</li>
+ * 			<li>encrypted private key could be stored in Qortal AT for access by Bob from any node</li>
+ * 		</ul>
+ * </li>
+ * <li>Bob deploys Qortal AT
+ * 		<ul>
+ * 		</ul>
+ * </li>
+ * <li>Alice finds Qortal AT and wants to trade
+ * 		<ul>
+ * 			<li>Alice generates Litecoin & Qortal 'trade' keys</li>
+ * 			<li>Alice funds Litecoin P2SH-A</li>
+ * 			<li>Alice sends 'offer' MESSAGE to Bob from her Qortal trade address, containing:
+ * 				<ul>
+ * 					<li>hash-of-secret-A</li>
+ * 					<li>her 'trade' Litecoin PKH</li>
+ * 				</ul>
+ * 			</li>
+ * 		</ul>
+ * </li>
+ * <li>Bob receives "offer" MESSAGE
+ * 		<ul>
+ * 			<li>Checks Alice's P2SH-A</li>
+ * 			<li>Sends 'trade' MESSAGE to Qortal AT from his trade address, containing:
+ * 				<ul>
+ * 					<li>Alice's trade Qortal address</li>
+ * 					<li>Alice's trade Litecoin PKH</li>
+ * 					<li>hash-of-secret-A</li>
+ * 				</ul>
+ * 			</li>
+ * 		</ul>
+ * </li>
+ * <li>Alice checks Qortal AT to confirm it's locked to her
+ * 		<ul>
+ * 			<li>Alice sends 'redeem' MESSAGE to Qortal AT from her trade address, containing:
+ * 				<ul>
+ * 					<li>secret-A</li>
+ * 					<li>Qortal receiving address of her chosing</li>
+ * 				</ul>
+ * 			</li>
+ * 			<li>AT's QORT funds are sent to Qortal receiving address</li>
+ * 		</ul>
+ * </li>
+ * <li>Bob checks AT, extracts secret-A
+ * 		<ul>
+ * 			<li>Bob redeems P2SH-A using his Litecoin trade key and secret-A</li>
+ * 			<li>P2SH-A LTC funds end up at Litecoin address determined by redeem transaction output(s)</li>
+ * 		</ul>
+ * </li>
+ * </ul>
+ */
+public class LitecoinACCTv2 implements ACCT {
+
+	public static final String NAME = LitecoinACCTv2.class.getSimpleName();
+	public static final byte[] CODE_BYTES_HASH = HashCode.fromString("d5ea386a41441180c854ca8d7bbc620bfd53a97df2650a2b162b52324caf6e19").asBytes(); // SHA256 of AT code bytes
+
+	public static final int SECRET_LENGTH = 32;
+
+	/** <b>Value</b> offset into AT segment where 'mode' variable (long) is stored. (Multiply by MachineState.VALUE_SIZE for byte offset). */
+	private static final int MODE_VALUE_OFFSET = 61;
+	/** <b>Byte</b> offset into AT state data where 'mode' variable (long) is stored. */
+	public static final int MODE_BYTE_OFFSET = MachineState.HEADER_LENGTH + (MODE_VALUE_OFFSET * MachineState.VALUE_SIZE);
+
+	public static class OfferMessageData {
+		public byte[] partnerLitecoinPKH;
+		public byte[] hashOfSecretA;
+		public long lockTimeA;
+	}
+	public static final int OFFER_MESSAGE_LENGTH = 20 /*partnerLitecoinPKH*/ + 20 /*hashOfSecretA*/ + 8 /*lockTimeA*/;
+	public static final int TRADE_MESSAGE_LENGTH = 32 /*partner's Qortal trade address (padded from 25 to 32)*/
+			+ 24 /*partner's Litecoin PKH (padded from 20 to 24)*/
+			+ 8 /*AT trade timeout (minutes)*/
+			+ 24 /*hash of secret-A (padded from 20 to 24)*/
+			+ 8 /*lockTimeA*/;
+	public static final int REDEEM_MESSAGE_LENGTH = 32 /*secret-A*/ + 32 /*partner's Qortal receiving address padded from 25 to 32*/;
+	public static final int CANCEL_MESSAGE_LENGTH = 32 /*AT creator's Qortal address*/;
+
+	private static LitecoinACCTv2 instance;
+
+	private LitecoinACCTv2() {
+	}
+
+	public static synchronized LitecoinACCTv2 getInstance() {
+		if (instance == null)
+			instance = new LitecoinACCTv2();
+
+		return instance;
+	}
+
+	@Override
+	public byte[] getCodeBytesHash() {
+		return CODE_BYTES_HASH;
+	}
+
+	@Override
+	public int getModeByteOffset() {
+		return MODE_BYTE_OFFSET;
+	}
+
+	@Override
+	public ForeignBlockchain getBlockchain() {
+		return Litecoin.getInstance();
+	}
+
+	/**
+	 * Returns Qortal AT creation bytes for cross-chain trading AT.
+	 * <p>
+	 * <tt>tradeTimeout</tt> (minutes) is the time window for the trade partner to send the
+	 * 32-byte secret to the AT, before the AT automatically refunds the AT's creator.
+	 * 
+	 * @param creatorTradeAddress AT creator's trade Qortal address
+	 * @param litecoinPublicKeyHash 20-byte HASH160 of creator's trade Litecoin public key
+	 * @param qortAmount how much QORT to pay trade partner if they send correct 32-byte secrets to AT
+	 * @param litecoinAmount how much LTC the AT creator is expecting to trade
+	 * @param tradeTimeout suggested timeout for entire trade
+	 */
+	public static byte[] buildQortalAT(String creatorTradeAddress, byte[] litecoinPublicKeyHash, long qortAmount, long litecoinAmount, int tradeTimeout) {
+		if (litecoinPublicKeyHash.length != 20)
+			throw new IllegalArgumentException("Litecoin public key hash should be 20 bytes");
+
+		// Labels for data segment addresses
+		int addrCounter = 0;
+
+		// Constants (with corresponding dataByteBuffer.put*() calls below)
+
+		final int addrCreatorTradeAddress1 = addrCounter++;
+		final int addrCreatorTradeAddress2 = addrCounter++;
+		final int addrCreatorTradeAddress3 = addrCounter++;
+		final int addrCreatorTradeAddress4 = addrCounter++;
+
+		final int addrLitecoinPublicKeyHash = addrCounter;
+		addrCounter += 4;
+
+		final int addrQortAmount = addrCounter++;
+		final int addrLitecoinAmount = addrCounter++;
+		final int addrTradeTimeout = addrCounter++;
+
+		final int addrMessageTxnType = addrCounter++;
+		final int addrExpectedTradeMessageLength = addrCounter++;
+		final int addrExpectedRedeemMessageLength = addrCounter++;
+
+		final int addrCreatorAddressPointer = addrCounter++;
+		final int addrQortalPartnerAddressPointer = addrCounter++;
+		final int addrMessageSenderPointer = addrCounter++;
+
+		final int addrTradeMessagePartnerLitecoinPKHOffset = addrCounter++;
+		final int addrPartnerLitecoinPKHPointer = addrCounter++;
+		final int addrTradeMessageHashOfSecretAOffset = addrCounter++;
+		final int addrHashOfSecretAPointer = addrCounter++;
+
+		final int addrRedeemMessageReceivingAddressOffset = addrCounter++;
+
+		final int addrMessageDataPointer = addrCounter++;
+		final int addrMessageDataLength = addrCounter++;
+
+		final int addrPartnerReceivingAddressPointer = addrCounter++;
+
+		final int addrEndOfConstants = addrCounter;
+
+		// Variables
+
+		final int addrCreatorAddress1 = addrCounter++;
+		final int addrCreatorAddress2 = addrCounter++;
+		final int addrCreatorAddress3 = addrCounter++;
+		final int addrCreatorAddress4 = addrCounter++;
+
+		final int addrQortalPartnerAddress1 = addrCounter++;
+		final int addrQortalPartnerAddress2 = addrCounter++;
+		final int addrQortalPartnerAddress3 = addrCounter++;
+		final int addrQortalPartnerAddress4 = addrCounter++;
+
+		final int addrLockTimeA = addrCounter++;
+		final int addrRefundTimeout = addrCounter++;
+		final int addrRefundTimestamp = addrCounter++;
+		final int addrLastTxnTimestamp = addrCounter++;
+		final int addrBlockTimestamp = addrCounter++;
+		final int addrTxnType = addrCounter++;
+		final int addrResult = addrCounter++;
+
+		final int addrMessageSender1 = addrCounter++;
+		final int addrMessageSender2 = addrCounter++;
+		final int addrMessageSender3 = addrCounter++;
+		final int addrMessageSender4 = addrCounter++;
+
+		final int addrMessageLength = addrCounter++;
+
+		final int addrMessageData = addrCounter;
+		addrCounter += 4;
+
+		final int addrHashOfSecretA = addrCounter;
+		addrCounter += 4;
+
+		final int addrPartnerLitecoinPKH = addrCounter;
+		addrCounter += 4;
+
+		final int addrPartnerReceivingAddress = addrCounter;
+		addrCounter += 4;
+
+		final int addrMode = addrCounter++;
+		assert addrMode == MODE_VALUE_OFFSET : String.format("addrMode %d does not match MODE_VALUE_OFFSET %d", addrMode, MODE_VALUE_OFFSET);
+
+		// Data segment
+		ByteBuffer dataByteBuffer = ByteBuffer.allocate(addrCounter * MachineState.VALUE_SIZE);
+
+		// AT creator's trade Qortal address, decoded from Base58
+		assert dataByteBuffer.position() == addrCreatorTradeAddress1 * MachineState.VALUE_SIZE : "addrCreatorTradeAddress1 incorrect";
+		byte[] creatorTradeAddressBytes = Base58.decode(creatorTradeAddress);
+		dataByteBuffer.put(Bytes.ensureCapacity(creatorTradeAddressBytes, 32, 0));
+
+		// Litecoin public key hash
+		assert dataByteBuffer.position() == addrLitecoinPublicKeyHash * MachineState.VALUE_SIZE : "addrLitecoinPublicKeyHash incorrect";
+		dataByteBuffer.put(Bytes.ensureCapacity(litecoinPublicKeyHash, 32, 0));
+
+		// Redeem Qort amount
+		assert dataByteBuffer.position() == addrQortAmount * MachineState.VALUE_SIZE : "addrQortAmount incorrect";
+		dataByteBuffer.putLong(qortAmount);
+
+		// Expected Litecoin amount
+		assert dataByteBuffer.position() == addrLitecoinAmount * MachineState.VALUE_SIZE : "addrLitecoinAmount incorrect";
+		dataByteBuffer.putLong(litecoinAmount);
+
+		// Suggested trade timeout (minutes)
+		assert dataByteBuffer.position() == addrTradeTimeout * MachineState.VALUE_SIZE : "addrTradeTimeout incorrect";
+		dataByteBuffer.putLong(tradeTimeout);
+
+		// We're only interested in MESSAGE transactions
+		assert dataByteBuffer.position() == addrMessageTxnType * MachineState.VALUE_SIZE : "addrMessageTxnType incorrect";
+		dataByteBuffer.putLong(API.ATTransactionType.MESSAGE.value);
+
+		// Expected length of 'trade' MESSAGE data from AT creator
+		assert dataByteBuffer.position() == addrExpectedTradeMessageLength * MachineState.VALUE_SIZE : "addrExpectedTradeMessageLength incorrect";
+		dataByteBuffer.putLong(TRADE_MESSAGE_LENGTH);
+
+		// Expected length of 'redeem' MESSAGE data from trade partner
+		assert dataByteBuffer.position() == addrExpectedRedeemMessageLength * MachineState.VALUE_SIZE : "addrExpectedRedeemMessageLength incorrect";
+		dataByteBuffer.putLong(REDEEM_MESSAGE_LENGTH);
+
+		// Index into data segment of AT creator's address, used by GET_B_IND
+		assert dataByteBuffer.position() == addrCreatorAddressPointer * MachineState.VALUE_SIZE : "addrCreatorAddressPointer incorrect";
+		dataByteBuffer.putLong(addrCreatorAddress1);
+
+		// Index into data segment of partner's Qortal address, used by SET_B_IND
+		assert dataByteBuffer.position() == addrQortalPartnerAddressPointer * MachineState.VALUE_SIZE : "addrQortalPartnerAddressPointer incorrect";
+		dataByteBuffer.putLong(addrQortalPartnerAddress1);
+
+		// Index into data segment of (temporary) transaction's sender's address, used by GET_B_IND
+		assert dataByteBuffer.position() == addrMessageSenderPointer * MachineState.VALUE_SIZE : "addrMessageSenderPointer incorrect";
+		dataByteBuffer.putLong(addrMessageSender1);
+
+		// Offset into 'trade' MESSAGE data payload for extracting partner's Litecoin PKH
+		assert dataByteBuffer.position() == addrTradeMessagePartnerLitecoinPKHOffset * MachineState.VALUE_SIZE : "addrTradeMessagePartnerLitecoinPKHOffset incorrect";
+		dataByteBuffer.putLong(32L);
+
+		// Index into data segment of partner's Litecoin PKH, used by GET_B_IND
+		assert dataByteBuffer.position() == addrPartnerLitecoinPKHPointer * MachineState.VALUE_SIZE : "addrPartnerLitecoinPKHPointer incorrect";
+		dataByteBuffer.putLong(addrPartnerLitecoinPKH);
+
+		// Offset into 'trade' MESSAGE data payload for extracting hash-of-secret-A
+		assert dataByteBuffer.position() == addrTradeMessageHashOfSecretAOffset * MachineState.VALUE_SIZE : "addrTradeMessageHashOfSecretAOffset incorrect";
+		dataByteBuffer.putLong(64L);
+
+		// Index into data segment to hash of secret A, used by GET_B_IND
+		assert dataByteBuffer.position() == addrHashOfSecretAPointer * MachineState.VALUE_SIZE : "addrHashOfSecretAPointer incorrect";
+		dataByteBuffer.putLong(addrHashOfSecretA);
+
+		// Offset into 'redeem' MESSAGE data payload for extracting Qortal receiving address
+		assert dataByteBuffer.position() == addrRedeemMessageReceivingAddressOffset * MachineState.VALUE_SIZE : "addrRedeemMessageReceivingAddressOffset incorrect";
+		dataByteBuffer.putLong(32L);
+
+		// Source location and length for hashing any passed secret
+		assert dataByteBuffer.position() == addrMessageDataPointer * MachineState.VALUE_SIZE : "addrMessageDataPointer incorrect";
+		dataByteBuffer.putLong(addrMessageData);
+		assert dataByteBuffer.position() == addrMessageDataLength * MachineState.VALUE_SIZE : "addrMessageDataLength incorrect";
+		dataByteBuffer.putLong(32L);
+
+		// Pointer into data segment of where to save partner's receiving Qortal address, used by GET_B_IND
+		assert dataByteBuffer.position() == addrPartnerReceivingAddressPointer * MachineState.VALUE_SIZE : "addrPartnerReceivingAddressPointer incorrect";
+		dataByteBuffer.putLong(addrPartnerReceivingAddress);
+
+		assert dataByteBuffer.position() == addrEndOfConstants * MachineState.VALUE_SIZE : "dataByteBuffer position not at end of constants";
+
+		// Code labels
+		Integer labelRefund = null;
+
+		Integer labelTradeTxnLoop = null;
+		Integer labelCheckTradeTxn = null;
+		Integer labelCheckCancelTxn = null;
+		Integer labelNotTradeNorCancelTxn = null;
+		Integer labelCheckNonRefundTradeTxn = null;
+		Integer labelTradeTxnExtract = null;
+		Integer labelRedeemTxnLoop = null;
+		Integer labelCheckRedeemTxn = null;
+		Integer labelCheckRedeemTxnSender = null;
+		Integer labelPayout = null;
+
+		ByteBuffer codeByteBuffer = ByteBuffer.allocate(768);
+
+		// Two-pass version
+		for (int pass = 0; pass < 2; ++pass) {
+			codeByteBuffer.clear();
+
+			try {
+				/* Initialization */
+
+				// Use AT creation 'timestamp' as starting point for finding transactions sent to AT
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_CREATION_TIMESTAMP, addrLastTxnTimestamp));
+
+				// Load B register with AT creator's address so we can save it into addrCreatorAddress1-4
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_CREATOR_INTO_B));
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrCreatorAddressPointer));
+
+				// Set restart position to after this opcode
+				codeByteBuffer.put(OpCode.SET_PCS.compile());
+
+				/* Loop, waiting for message from AT creator's trade address containing trade partner details, or AT owner's address to cancel offer */
+
+				/* Transaction processing loop */
+				labelTradeTxnLoop = codeByteBuffer.position();
+
+				/* Sleep until message arrives */
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.SLEEP_UNTIL_MESSAGE.value, addrLastTxnTimestamp));
+
+				// Find next transaction (if any) to this AT since the last one (referenced by addrLastTxnTimestamp)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PUT_TX_AFTER_TIMESTAMP_INTO_A, addrLastTxnTimestamp));
+				// If no transaction found, A will be zero. If A is zero, set addrResult to 1, otherwise 0.
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.CHECK_A_IS_ZERO, addrResult));
+				// If addrResult is zero (i.e. A is non-zero, transaction was found) then go check transaction
+				codeByteBuffer.put(OpCode.BZR_DAT.compile(addrResult, calcOffset(codeByteBuffer, labelCheckTradeTxn)));
+				// Stop and wait for next block
+				codeByteBuffer.put(OpCode.STP_IMD.compile());
+
+				/* Check transaction */
+				labelCheckTradeTxn = codeByteBuffer.position();
+
+				// Update our 'last found transaction's timestamp' using 'timestamp' from transaction
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TIMESTAMP_FROM_TX_IN_A, addrLastTxnTimestamp));
+				// Extract transaction type (message/payment) from transaction and save type in addrTxnType
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TYPE_FROM_TX_IN_A, addrTxnType));
+				// If transaction type is not MESSAGE type then go look for another transaction
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrTxnType, addrMessageTxnType, calcOffset(codeByteBuffer, labelTradeTxnLoop)));
+
+				/* Check transaction's sender. We're expecting AT creator's trade address for 'trade' message, or AT creator's own address for 'cancel' message. */
+
+				// Extract sender address from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_ADDRESS_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrMessageSender1 (as pointed to by addrMessageSenderPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrMessageSenderPointer));
+				// Compare each part of message sender's address with AT creator's trade address. If they don't match, check for cancel situation.
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender1, addrCreatorTradeAddress1, calcOffset(codeByteBuffer, labelCheckCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender2, addrCreatorTradeAddress2, calcOffset(codeByteBuffer, labelCheckCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender3, addrCreatorTradeAddress3, calcOffset(codeByteBuffer, labelCheckCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender4, addrCreatorTradeAddress4, calcOffset(codeByteBuffer, labelCheckCancelTxn)));
+				// Message sender's address matches AT creator's trade address so go process 'trade' message
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelCheckNonRefundTradeTxn == null ? 0 : labelCheckNonRefundTradeTxn));
+
+				/* Checking message sender for possible cancel message */
+				labelCheckCancelTxn = codeByteBuffer.position();
+
+				// Compare each part of message sender's address with AT creator's address. If they don't match, look for another transaction.
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender1, addrCreatorAddress1, calcOffset(codeByteBuffer, labelNotTradeNorCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender2, addrCreatorAddress2, calcOffset(codeByteBuffer, labelNotTradeNorCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender3, addrCreatorAddress3, calcOffset(codeByteBuffer, labelNotTradeNorCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender4, addrCreatorAddress4, calcOffset(codeByteBuffer, labelNotTradeNorCancelTxn)));
+				// Partner address is AT creator's address, so cancel offer and finish.
+				codeByteBuffer.put(OpCode.SET_VAL.compile(addrMode, AcctMode.CANCELLED.value));
+				// We're finished forever (finishing auto-refunds remaining balance to AT creator)
+				codeByteBuffer.put(OpCode.FIN_IMD.compile());
+
+				/* Not trade nor cancel message */
+				labelNotTradeNorCancelTxn = codeByteBuffer.position();
+
+				// Loop to find another transaction
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelTradeTxnLoop == null ? 0 : labelTradeTxnLoop));
+
+				/* Possible switch-to-trade-mode message */
+				labelCheckNonRefundTradeTxn = codeByteBuffer.position();
+
+				// Check 'trade' message we received has expected number of message bytes
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(QortalFunctionCode.GET_MESSAGE_LENGTH_FROM_TX_IN_A.value, addrMessageLength));
+				// If message length matches, branch to info extraction code
+				codeByteBuffer.put(OpCode.BEQ_DAT.compile(addrMessageLength, addrExpectedTradeMessageLength, calcOffset(codeByteBuffer, labelTradeTxnExtract)));
+				// Message length didn't match - go back to finding another 'trade' MESSAGE transaction
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelTradeTxnLoop == null ? 0 : labelTradeTxnLoop));
+
+				/* Extracting info from 'trade' MESSAGE transaction */
+				labelTradeTxnExtract = codeByteBuffer.position();
+
+				// Extract message from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_MESSAGE_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrQortalPartnerAddress1 (as pointed to by addrQortalPartnerAddressPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrQortalPartnerAddressPointer));
+
+				// Extract trade partner's Litecoin public key hash (PKH) from message into B
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.PUT_PARTIAL_MESSAGE_FROM_TX_IN_A_INTO_B.value, addrTradeMessagePartnerLitecoinPKHOffset));
+				// Store partner's Litecoin PKH (we only really use values from B1-B3)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrPartnerLitecoinPKHPointer));
+				// Extract AT trade timeout (minutes) (from B4)
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_B4, addrRefundTimeout));
+
+				// Grab next 32 bytes
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.PUT_PARTIAL_MESSAGE_FROM_TX_IN_A_INTO_B.value, addrTradeMessageHashOfSecretAOffset));
+
+				// Extract hash-of-secret-A (we only really use values from B1-B3)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrHashOfSecretAPointer));
+				// Extract lockTime-A (from B4)
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_B4, addrLockTimeA));
+
+				// Calculate trade timeout refund 'timestamp' by adding addrRefundTimeout minutes to this transaction's 'timestamp', then save into addrRefundTimestamp
+				codeByteBuffer.put(OpCode.EXT_FUN_RET_DAT_2.compile(FunctionCode.ADD_MINUTES_TO_TIMESTAMP, addrRefundTimestamp, addrLastTxnTimestamp, addrRefundTimeout));
+
+				/* We are in 'trade mode' */
+				codeByteBuffer.put(OpCode.SET_VAL.compile(addrMode, AcctMode.TRADING.value));
+
+				// Set restart position to after this opcode
+				codeByteBuffer.put(OpCode.SET_PCS.compile());
+
+				/* Loop, waiting for trade timeout or 'redeem' MESSAGE from Qortal trade partner */
+
+				// Fetch current block 'timestamp'
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_BLOCK_TIMESTAMP, addrBlockTimestamp));
+				// If we're not past refund 'timestamp' then look for next transaction
+				codeByteBuffer.put(OpCode.BLT_DAT.compile(addrBlockTimestamp, addrRefundTimestamp, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+				// We're past refund 'timestamp' so go refund everything back to AT creator
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelRefund == null ? 0 : labelRefund));
+
+				/* Transaction processing loop */
+				labelRedeemTxnLoop = codeByteBuffer.position();
+
+				/* Sleep until message arrives */
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.SLEEP_UNTIL_MESSAGE.value, addrLastTxnTimestamp));
+
+				// Find next transaction to this AT since the last one (if any)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PUT_TX_AFTER_TIMESTAMP_INTO_A, addrLastTxnTimestamp));
+				// If no transaction found, A will be zero. If A is zero, set addrComparator to 1, otherwise 0.
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.CHECK_A_IS_ZERO, addrResult));
+				// If addrResult is zero (i.e. A is non-zero, transaction was found) then go check transaction
+				codeByteBuffer.put(OpCode.BZR_DAT.compile(addrResult, calcOffset(codeByteBuffer, labelCheckRedeemTxn)));
+				// Stop and wait for next block
+				codeByteBuffer.put(OpCode.STP_IMD.compile());
+
+				/* Check transaction */
+				labelCheckRedeemTxn = codeByteBuffer.position();
+
+				// Update our 'last found transaction's timestamp' using 'timestamp' from transaction
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TIMESTAMP_FROM_TX_IN_A, addrLastTxnTimestamp));
+				// Extract transaction type (message/payment) from transaction and save type in addrTxnType
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TYPE_FROM_TX_IN_A, addrTxnType));
+				// If transaction type is not MESSAGE type then go look for another transaction
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrTxnType, addrMessageTxnType, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+
+				/* Check message payload length */
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(QortalFunctionCode.GET_MESSAGE_LENGTH_FROM_TX_IN_A.value, addrMessageLength));
+				// If message length matches, branch to sender checking code
+				codeByteBuffer.put(OpCode.BEQ_DAT.compile(addrMessageLength, addrExpectedRedeemMessageLength, calcOffset(codeByteBuffer, labelCheckRedeemTxnSender)));
+				// Message length didn't match - go back to finding another 'redeem' MESSAGE transaction
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelRedeemTxnLoop == null ? 0 : labelRedeemTxnLoop));
+
+				/* Check transaction's sender */
+				labelCheckRedeemTxnSender = codeByteBuffer.position();
+
+				// Extract sender address from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_ADDRESS_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrMessageSender1 (as pointed to by addrMessageSenderPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrMessageSenderPointer));
+				// Compare each part of transaction's sender's address with expected address. If they don't match, look for another transaction.
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender1, addrQortalPartnerAddress1, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender2, addrQortalPartnerAddress2, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender3, addrQortalPartnerAddress3, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender4, addrQortalPartnerAddress4, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+
+				/* Check 'secret-A' in transaction's message */
+
+				// Extract secret-A from first 32 bytes of message from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_MESSAGE_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrMessageData (as pointed to by addrMessageDataPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrMessageDataPointer));
+				// Load B register with expected hash result (as pointed to by addrHashOfSecretAPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.SET_B_IND, addrHashOfSecretAPointer));
+				// Perform HASH160 using source data at addrMessageData. (Location and length specified via addrMessageDataPointer and addrMessageDataLength).
+				// Save the equality result (1 if they match, 0 otherwise) into addrResult.
+				codeByteBuffer.put(OpCode.EXT_FUN_RET_DAT_2.compile(FunctionCode.CHECK_HASH160_WITH_B, addrResult, addrMessageDataPointer, addrMessageDataLength));
+				// If hashes don't match, addrResult will be zero so go find another transaction
+				codeByteBuffer.put(OpCode.BNZ_DAT.compile(addrResult, calcOffset(codeByteBuffer, labelPayout)));
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelRedeemTxnLoop == null ? 0 : labelRedeemTxnLoop));
+
+				/* Success! Pay arranged amount to receiving address */
+				labelPayout = codeByteBuffer.position();
+
+				// Extract Qortal receiving address from next 32 bytes of message from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.PUT_PARTIAL_MESSAGE_FROM_TX_IN_A_INTO_B.value, addrRedeemMessageReceivingAddressOffset));
+				// Save B register into data segment starting at addrPartnerReceivingAddress (as pointed to by addrPartnerReceivingAddressPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrPartnerReceivingAddressPointer));
+				// Pay AT's balance to receiving address
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PAY_TO_ADDRESS_IN_B, addrQortAmount));
+				// Set redeemed mode
+				codeByteBuffer.put(OpCode.SET_VAL.compile(addrMode, AcctMode.REDEEMED.value));
+				// We're finished forever (finishing auto-refunds remaining balance to AT creator)
+				codeByteBuffer.put(OpCode.FIN_IMD.compile());
+
+				// Fall-through to refunding any remaining balance back to AT creator
+
+				/* Refund balance back to AT creator */
+				labelRefund = codeByteBuffer.position();
+
+				// Set refunded mode
+				codeByteBuffer.put(OpCode.SET_VAL.compile(addrMode, AcctMode.REFUNDED.value));
+				// We're finished forever (finishing auto-refunds remaining balance to AT creator)
+				codeByteBuffer.put(OpCode.FIN_IMD.compile());
+			} catch (CompilationException e) {
+				throw new IllegalStateException("Unable to compile LTC-QORT ACCT?", e);
+			}
+		}
+
+		codeByteBuffer.flip();
+
+		byte[] codeBytes = new byte[codeByteBuffer.limit()];
+		codeByteBuffer.get(codeBytes);
+
+		assert Arrays.equals(Crypto.digest(codeBytes), LitecoinACCTv2.CODE_BYTES_HASH)
+			: String.format("BTCACCT.CODE_BYTES_HASH mismatch: expected %s, actual %s", HashCode.fromBytes(CODE_BYTES_HASH), HashCode.fromBytes(Crypto.digest(codeBytes)));
+
+		final short ciyamAtVersion = 2;
+		final short numCallStackPages = 0;
+		final short numUserStackPages = 0;
+		final long minActivationAmount = 0L;
+
+		return MachineState.toCreationBytes(ciyamAtVersion, codeBytes, dataByteBuffer.array(), numCallStackPages, numUserStackPages, minActivationAmount);
+	}
+
+	/**
+	 * Returns CrossChainTradeData with useful info extracted from AT.
+	 */
+	@Override
+	public CrossChainTradeData populateTradeData(Repository repository, ATData atData) throws DataException {
+		ATStateData atStateData = repository.getATRepository().getLatestATState(atData.getATAddress());
+		return populateTradeData(repository, atData.getCreatorPublicKey(), atData.getCreation(), atStateData);
+	}
+
+	/**
+	 * Returns CrossChainTradeData with useful info extracted from AT.
+	 */
+	@Override
+	public CrossChainTradeData populateTradeData(Repository repository, ATStateData atStateData) throws DataException {
+		ATData atData = repository.getATRepository().fromATAddress(atStateData.getATAddress());
+		return populateTradeData(repository, atData.getCreatorPublicKey(), atData.getCreation(), atStateData);
+	}
+
+	/**
+	 * Returns CrossChainTradeData with useful info extracted from AT.
+	 */
+	public CrossChainTradeData populateTradeData(Repository repository, byte[] creatorPublicKey, long creationTimestamp, ATStateData atStateData) throws DataException {
+		byte[] addressBytes = new byte[25]; // for general use
+		String atAddress = atStateData.getATAddress();
+
+		CrossChainTradeData tradeData = new CrossChainTradeData();
+
+		tradeData.foreignBlockchain = SupportedBlockchain.LITECOIN.name();
+		tradeData.acctName = NAME;
+
+		tradeData.qortalAtAddress = atAddress;
+		tradeData.qortalCreator = Crypto.toAddress(creatorPublicKey);
+		tradeData.creationTimestamp = creationTimestamp;
+
+		Account atAccount = new Account(repository, atAddress);
+		tradeData.qortBalance = atAccount.getConfirmedBalance(Asset.QORT);
+
+		byte[] stateData = atStateData.getStateData();
+		ByteBuffer dataByteBuffer = ByteBuffer.wrap(stateData);
+		dataByteBuffer.position(MachineState.HEADER_LENGTH);
+
+		/* Constants */
+
+		// Skip creator's trade address
+		dataByteBuffer.get(addressBytes);
+		tradeData.qortalCreatorTradeAddress = Base58.encode(addressBytes);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - addressBytes.length);
+
+		// Creator's Litecoin/foreign public key hash
+		tradeData.creatorForeignPKH = new byte[20];
+		dataByteBuffer.get(tradeData.creatorForeignPKH);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - tradeData.creatorForeignPKH.length); // skip to 32 bytes
+
+		// We don't use secret-B
+		tradeData.hashOfSecretB = null;
+
+		// Redeem payout
+		tradeData.qortAmount = dataByteBuffer.getLong();
+
+		// Expected LTC amount
+		tradeData.expectedForeignAmount = dataByteBuffer.getLong();
+
+		// Trade timeout
+		tradeData.tradeTimeout = (int) dataByteBuffer.getLong();
+
+		// Skip MESSAGE transaction type
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip expected 'trade' message length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip expected 'redeem' message length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to creator's address
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to partner's Qortal trade address
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to message sender
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip 'trade' message data offset for partner's Litecoin PKH
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to partner's Litecoin PKH
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip 'trade' message data offset for hash-of-secret-A
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to hash-of-secret-A
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip 'redeem' message data offset for partner's Qortal receiving address
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to message data
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip message data length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to partner's receiving address
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		/* End of constants / begin variables */
+
+		// Skip AT creator's address
+		dataByteBuffer.position(dataByteBuffer.position() + 8 * 4);
+
+		// Partner's trade address (if present)
+		dataByteBuffer.get(addressBytes);
+		String qortalRecipient = Base58.encode(addressBytes);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - addressBytes.length);
+
+		// Potential lockTimeA (if in trade mode)
+		int lockTimeA = (int) dataByteBuffer.getLong();
+
+		// AT refund timeout (probably only useful for debugging)
+		int refundTimeout = (int) dataByteBuffer.getLong();
+
+		// Trade-mode refund timestamp (AT 'timestamp' converted to Qortal block height)
+		long tradeRefundTimestamp = dataByteBuffer.getLong();
+
+		// Skip last transaction timestamp
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip block timestamp
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip transaction type
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip temporary result
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip temporary message sender
+		dataByteBuffer.position(dataByteBuffer.position() + 8 * 4);
+
+		// Skip message length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip temporary message data
+		dataByteBuffer.position(dataByteBuffer.position() + 8 * 4);
+
+		// Potential hash160 of secret A
+		byte[] hashOfSecretA = new byte[20];
+		dataByteBuffer.get(hashOfSecretA);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - hashOfSecretA.length); // skip to 32 bytes
+
+		// Potential partner's Litecoin PKH
+		byte[] partnerLitecoinPKH = new byte[20];
+		dataByteBuffer.get(partnerLitecoinPKH);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - partnerLitecoinPKH.length); // skip to 32 bytes
+
+		// Partner's receiving address (if present)
+		byte[] partnerReceivingAddress = new byte[25];
+		dataByteBuffer.get(partnerReceivingAddress);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - partnerReceivingAddress.length); // skip to 32 bytes
+
+		// Trade AT's 'mode'
+		long modeValue = dataByteBuffer.getLong();
+		AcctMode mode = AcctMode.valueOf((int) (modeValue & 0xffL));
+
+		/* End of variables */
+
+		if (mode != null && mode != AcctMode.OFFERING) {
+			tradeData.mode = mode;
+			tradeData.refundTimeout = refundTimeout;
+			tradeData.tradeRefundHeight = new Timestamp(tradeRefundTimestamp).blockHeight;
+			tradeData.qortalPartnerAddress = qortalRecipient;
+			tradeData.hashOfSecretA = hashOfSecretA;
+			tradeData.partnerForeignPKH = partnerLitecoinPKH;
+			tradeData.lockTimeA = lockTimeA;
+
+			if (mode == AcctMode.REDEEMED)
+				tradeData.qortalPartnerReceivingAddress = Base58.encode(partnerReceivingAddress);
+		} else {
+			tradeData.mode = AcctMode.OFFERING;
+		}
+
+		tradeData.duplicateDeprecated();
+
+		return tradeData;
+	}
+
+	/** Returns 'offer' MESSAGE payload for trade partner to send to AT creator's trade address. */
+	public static byte[] buildOfferMessage(byte[] partnerBitcoinPKH, byte[] hashOfSecretA, int lockTimeA) {
+		byte[] lockTimeABytes = BitTwiddling.toBEByteArray((long) lockTimeA);
+		return Bytes.concat(partnerBitcoinPKH, hashOfSecretA, lockTimeABytes);
+	}
+
+	/** Returns info extracted from 'offer' MESSAGE payload sent by trade partner to AT creator's trade address, or null if not valid. */
+	public static OfferMessageData extractOfferMessageData(byte[] messageData) {
+		if (messageData == null || messageData.length != OFFER_MESSAGE_LENGTH)
+			return null;
+
+		OfferMessageData offerMessageData = new OfferMessageData();
+		offerMessageData.partnerLitecoinPKH = Arrays.copyOfRange(messageData, 0, 20);
+		offerMessageData.hashOfSecretA = Arrays.copyOfRange(messageData, 20, 40);
+		offerMessageData.lockTimeA = BitTwiddling.longFromBEBytes(messageData, 40);
+
+		return offerMessageData;
+	}
+
+	/** Returns 'trade' MESSAGE payload for AT creator to send to AT. */
+	public static byte[] buildTradeMessage(String partnerQortalTradeAddress, byte[] partnerBitcoinPKH, byte[] hashOfSecretA, int lockTimeA, int refundTimeout) {
+		byte[] data = new byte[TRADE_MESSAGE_LENGTH];
+		byte[] partnerQortalAddressBytes = Base58.decode(partnerQortalTradeAddress);
+		byte[] lockTimeABytes = BitTwiddling.toBEByteArray((long) lockTimeA);
+		byte[] refundTimeoutBytes = BitTwiddling.toBEByteArray((long) refundTimeout);
+
+		System.arraycopy(partnerQortalAddressBytes, 0, data, 0, partnerQortalAddressBytes.length);
+		System.arraycopy(partnerBitcoinPKH, 0, data, 32, partnerBitcoinPKH.length);
+		System.arraycopy(refundTimeoutBytes, 0, data, 56, refundTimeoutBytes.length);
+		System.arraycopy(hashOfSecretA, 0, data, 64, hashOfSecretA.length);
+		System.arraycopy(lockTimeABytes, 0, data, 88, lockTimeABytes.length);
+
+		return data;
+	}
+
+	/** Returns 'cancel' MESSAGE payload for AT creator to cancel trade AT. */
+	@Override
+	public byte[] buildCancelMessage(String creatorQortalAddress) {
+		byte[] data = new byte[CANCEL_MESSAGE_LENGTH];
+		byte[] creatorQortalAddressBytes = Base58.decode(creatorQortalAddress);
+
+		System.arraycopy(creatorQortalAddressBytes, 0, data, 0, creatorQortalAddressBytes.length);
+
+		return data;
+	}
+
+	/** Returns 'redeem' MESSAGE payload for trade partner to send to AT. */
+	public static byte[] buildRedeemMessage(byte[] secretA, String qortalReceivingAddress) {
+		byte[] data = new byte[REDEEM_MESSAGE_LENGTH];
+		byte[] qortalReceivingAddressBytes = Base58.decode(qortalReceivingAddress);
+
+		System.arraycopy(secretA, 0, data, 0, secretA.length);
+		System.arraycopy(qortalReceivingAddressBytes, 0, data, 32, qortalReceivingAddressBytes.length);
+
+		return data;
+	}
+
+	/** Returns refund timeout (minutes) based on trade partner's 'offer' MESSAGE timestamp and P2SH-A locktime. */
+	public static int calcRefundTimeout(long offerMessageTimestamp, int lockTimeA) {
+		// refund should be triggered halfway between offerMessageTimestamp and lockTimeA
+		return (int) ((lockTimeA - (offerMessageTimestamp / 1000L)) / 2L / 60L);
+	}
+
+	@Override
+	public byte[] findSecretA(Repository repository, CrossChainTradeData crossChainTradeData) throws DataException {
+		String atAddress = crossChainTradeData.qortalAtAddress;
+		String redeemerAddress = crossChainTradeData.qortalPartnerAddress;
+
+		// We don't have partner's public key so we check every message to AT
+		List<MessageTransactionData> messageTransactionsData = repository.getMessageRepository().getMessagesByParticipants(null, atAddress, null, null, null);
+		if (messageTransactionsData == null)
+			return null;
+
+		// Find 'redeem' message
+		for (MessageTransactionData messageTransactionData : messageTransactionsData) {
+			// Check message payload type/encryption
+			if (messageTransactionData.isText() || messageTransactionData.isEncrypted())
+				continue;
+
+			// Check message payload size
+			byte[] messageData = messageTransactionData.getData();
+			if (messageData.length != REDEEM_MESSAGE_LENGTH)
+				// Wrong payload length
+				continue;
+
+			// Check sender
+			if (!Crypto.toAddress(messageTransactionData.getSenderPublicKey()).equals(redeemerAddress))
+				// Wrong sender;
+				continue;
+
+			// Extract secretA
+			byte[] secretA = new byte[32];
+			System.arraycopy(messageData, 0, secretA, 0, secretA.length);
+
+			byte[] hashOfSecretA = Crypto.hash160(secretA);
+			if (!Arrays.equals(hashOfSecretA, crossChainTradeData.hashOfSecretA))
+				continue;
+
+			return secretA;
+		}
+
+		return null;
+	}
+
+}

src/main/java/org/qortal/crosschain/LitecoinACCTv3.java

@@ -0,0 +1,851 @@
+package org.qortal.crosschain;
+
+import com.google.common.hash.HashCode;
+import com.google.common.primitives.Bytes;
+import org.ciyam.at.*;
+import org.qortal.account.Account;
+import org.qortal.asset.Asset;
+import org.qortal.at.QortalFunctionCode;
+import org.qortal.crypto.Crypto;
+import org.qortal.data.at.ATData;
+import org.qortal.data.at.ATStateData;
+import org.qortal.data.crosschain.CrossChainTradeData;
+import org.qortal.data.transaction.MessageTransactionData;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.utils.Base58;
+import org.qortal.utils.BitTwiddling;
+
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.ciyam.at.OpCode.calcOffset;
+
+/**
+ * Cross-chain trade AT
+ * 
+ * <p>
+ * <ul>
+ * <li>Bob generates Litecoin & Qortal 'trade' keys
+ * 		<ul>
+ * 			<li>private key required to sign P2SH redeem tx</li>
+ * 			<li>private key could be used to create 'secret' (e.g. double-SHA256)</li>
+ * 			<li>encrypted private key could be stored in Qortal AT for access by Bob from any node</li>
+ * 		</ul>
+ * </li>
+ * <li>Bob deploys Qortal AT
+ * 		<ul>
+ * 		</ul>
+ * </li>
+ * <li>Alice finds Qortal AT and wants to trade
+ * 		<ul>
+ * 			<li>Alice generates Litecoin & Qortal 'trade' keys</li>
+ * 			<li>Alice funds Litecoin P2SH-A</li>
+ * 			<li>Alice sends 'offer' MESSAGE to Bob from her Qortal trade address, containing:
+ * 				<ul>
+ * 					<li>hash-of-secret-A</li>
+ * 					<li>her 'trade' Litecoin PKH</li>
+ * 				</ul>
+ * 			</li>
+ * 		</ul>
+ * </li>
+ * <li>Bob receives "offer" MESSAGE
+ * 		<ul>
+ * 			<li>Checks Alice's P2SH-A</li>
+ * 			<li>Sends 'trade' MESSAGE to Qortal AT from his trade address, containing:
+ * 				<ul>
+ * 					<li>Alice's trade Qortal address</li>
+ * 					<li>Alice's trade Litecoin PKH</li>
+ * 					<li>hash-of-secret-A</li>
+ * 				</ul>
+ * 			</li>
+ * 		</ul>
+ * </li>
+ * <li>Alice checks Qortal AT to confirm it's locked to her
+ * 		<ul>
+ * 			<li>Alice sends 'redeem' MESSAGE to Qortal AT from her trade address, containing:
+ * 				<ul>
+ * 					<li>secret-A</li>
+ * 					<li>Qortal receiving address of her chosing</li>
+ * 				</ul>
+ * 			</li>
+ * 			<li>AT's QORT funds are sent to Qortal receiving address</li>
+ * 		</ul>
+ * </li>
+ * <li>Bob checks AT, extracts secret-A
+ * 		<ul>
+ * 			<li>Bob redeems P2SH-A using his Litecoin trade key and secret-A</li>
+ * 			<li>P2SH-A LTC funds end up at Litecoin address determined by redeem transaction output(s)</li>
+ * 		</ul>
+ * </li>
+ * </ul>
+ */
+public class LitecoinACCTv3 implements ACCT {
+
+	public static final String NAME = LitecoinACCTv3.class.getSimpleName();
+	public static final byte[] CODE_BYTES_HASH = HashCode.fromString("31588e7ddb95a908bce310bb6dc76f011ff4693d2f8a3741fab3c989d56ce7c7").asBytes(); // SHA256 of AT code bytes
+
+	public static final int SECRET_LENGTH = 32;
+
+	/** <b>Value</b> offset into AT segment where 'mode' variable (long) is stored. (Multiply by MachineState.VALUE_SIZE for byte offset). */
+	private static final int MODE_VALUE_OFFSET = 61;
+	/** <b>Byte</b> offset into AT state data where 'mode' variable (long) is stored. */
+	public static final int MODE_BYTE_OFFSET = MachineState.HEADER_LENGTH + (MODE_VALUE_OFFSET * MachineState.VALUE_SIZE);
+
+	public static class OfferMessageData {
+		public byte[] partnerLitecoinPKH;
+		public byte[] hashOfSecretA;
+		public long lockTimeA;
+	}
+	public static final int OFFER_MESSAGE_LENGTH = 20 /*partnerLitecoinPKH*/ + 20 /*hashOfSecretA*/ + 8 /*lockTimeA*/;
+	public static final int TRADE_MESSAGE_LENGTH = 32 /*partner's Qortal trade address (padded from 25 to 32)*/
+			+ 24 /*partner's Litecoin PKH (padded from 20 to 24)*/
+			+ 8 /*AT trade timeout (minutes)*/
+			+ 24 /*hash of secret-A (padded from 20 to 24)*/
+			+ 8 /*lockTimeA*/;
+	public static final int REDEEM_MESSAGE_LENGTH = 32 /*secret-A*/ + 32 /*partner's Qortal receiving address padded from 25 to 32*/;
+	public static final int CANCEL_MESSAGE_LENGTH = 32 /*AT creator's Qortal address*/;
+
+	private static LitecoinACCTv3 instance;
+
+	private LitecoinACCTv3() {
+	}
+
+	public static synchronized LitecoinACCTv3 getInstance() {
+		if (instance == null)
+			instance = new LitecoinACCTv3();
+
+		return instance;
+	}
+
+	@Override
+	public byte[] getCodeBytesHash() {
+		return CODE_BYTES_HASH;
+	}
+
+	@Override
+	public int getModeByteOffset() {
+		return MODE_BYTE_OFFSET;
+	}
+
+	@Override
+	public ForeignBlockchain getBlockchain() {
+		return Litecoin.getInstance();
+	}
+
+	/**
+	 * Returns Qortal AT creation bytes for cross-chain trading AT.
+	 * <p>
+	 * <tt>tradeTimeout</tt> (minutes) is the time window for the trade partner to send the
+	 * 32-byte secret to the AT, before the AT automatically refunds the AT's creator.
+	 * 
+	 * @param creatorTradeAddress AT creator's trade Qortal address
+	 * @param litecoinPublicKeyHash 20-byte HASH160 of creator's trade Litecoin public key
+	 * @param qortAmount how much QORT to pay trade partner if they send correct 32-byte secrets to AT
+	 * @param litecoinAmount how much LTC the AT creator is expecting to trade
+	 * @param tradeTimeout suggested timeout for entire trade
+	 */
+	public static byte[] buildQortalAT(String creatorTradeAddress, byte[] litecoinPublicKeyHash, long qortAmount, long litecoinAmount, int tradeTimeout) {
+		if (litecoinPublicKeyHash.length != 20)
+			throw new IllegalArgumentException("Litecoin public key hash should be 20 bytes");
+
+		// Labels for data segment addresses
+		int addrCounter = 0;
+
+		// Constants (with corresponding dataByteBuffer.put*() calls below)
+
+		final int addrCreatorTradeAddress1 = addrCounter++;
+		final int addrCreatorTradeAddress2 = addrCounter++;
+		final int addrCreatorTradeAddress3 = addrCounter++;
+		final int addrCreatorTradeAddress4 = addrCounter++;
+
+		final int addrLitecoinPublicKeyHash = addrCounter;
+		addrCounter += 4;
+
+		final int addrQortAmount = addrCounter++;
+		final int addrLitecoinAmount = addrCounter++;
+		final int addrTradeTimeout = addrCounter++;
+
+		final int addrMessageTxnType = addrCounter++;
+		final int addrExpectedTradeMessageLength = addrCounter++;
+		final int addrExpectedRedeemMessageLength = addrCounter++;
+
+		final int addrCreatorAddressPointer = addrCounter++;
+		final int addrQortalPartnerAddressPointer = addrCounter++;
+		final int addrMessageSenderPointer = addrCounter++;
+
+		final int addrTradeMessagePartnerLitecoinPKHOffset = addrCounter++;
+		final int addrPartnerLitecoinPKHPointer = addrCounter++;
+		final int addrTradeMessageHashOfSecretAOffset = addrCounter++;
+		final int addrHashOfSecretAPointer = addrCounter++;
+
+		final int addrRedeemMessageReceivingAddressOffset = addrCounter++;
+
+		final int addrMessageDataPointer = addrCounter++;
+		final int addrMessageDataLength = addrCounter++;
+
+		final int addrPartnerReceivingAddressPointer = addrCounter++;
+
+		final int addrEndOfConstants = addrCounter;
+
+		// Variables
+
+		final int addrCreatorAddress1 = addrCounter++;
+		final int addrCreatorAddress2 = addrCounter++;
+		final int addrCreatorAddress3 = addrCounter++;
+		final int addrCreatorAddress4 = addrCounter++;
+
+		final int addrQortalPartnerAddress1 = addrCounter++;
+		final int addrQortalPartnerAddress2 = addrCounter++;
+		final int addrQortalPartnerAddress3 = addrCounter++;
+		final int addrQortalPartnerAddress4 = addrCounter++;
+
+		final int addrLockTimeA = addrCounter++;
+		final int addrRefundTimeout = addrCounter++;
+		final int addrRefundTimestamp = addrCounter++;
+		final int addrLastTxnTimestamp = addrCounter++;
+		final int addrBlockTimestamp = addrCounter++;
+		final int addrTxnType = addrCounter++;
+		final int addrResult = addrCounter++;
+
+		final int addrMessageSender1 = addrCounter++;
+		final int addrMessageSender2 = addrCounter++;
+		final int addrMessageSender3 = addrCounter++;
+		final int addrMessageSender4 = addrCounter++;
+
+		final int addrMessageLength = addrCounter++;
+
+		final int addrMessageData = addrCounter;
+		addrCounter += 4;
+
+		final int addrHashOfSecretA = addrCounter;
+		addrCounter += 4;
+
+		final int addrPartnerLitecoinPKH = addrCounter;
+		addrCounter += 4;
+
+		final int addrPartnerReceivingAddress = addrCounter;
+		addrCounter += 4;
+
+		final int addrMode = addrCounter++;
+		assert addrMode == MODE_VALUE_OFFSET : String.format("addrMode %d does not match MODE_VALUE_OFFSET %d", addrMode, MODE_VALUE_OFFSET);
+
+		// Data segment
+		ByteBuffer dataByteBuffer = ByteBuffer.allocate(addrCounter * MachineState.VALUE_SIZE);
+
+		// AT creator's trade Qortal address, decoded from Base58
+		assert dataByteBuffer.position() == addrCreatorTradeAddress1 * MachineState.VALUE_SIZE : "addrCreatorTradeAddress1 incorrect";
+		byte[] creatorTradeAddressBytes = Base58.decode(creatorTradeAddress);
+		dataByteBuffer.put(Bytes.ensureCapacity(creatorTradeAddressBytes, 32, 0));
+
+		// Litecoin public key hash
+		assert dataByteBuffer.position() == addrLitecoinPublicKeyHash * MachineState.VALUE_SIZE : "addrLitecoinPublicKeyHash incorrect";
+		dataByteBuffer.put(Bytes.ensureCapacity(litecoinPublicKeyHash, 32, 0));
+
+		// Redeem Qort amount
+		assert dataByteBuffer.position() == addrQortAmount * MachineState.VALUE_SIZE : "addrQortAmount incorrect";
+		dataByteBuffer.putLong(qortAmount);
+
+		// Expected Litecoin amount
+		assert dataByteBuffer.position() == addrLitecoinAmount * MachineState.VALUE_SIZE : "addrLitecoinAmount incorrect";
+		dataByteBuffer.putLong(litecoinAmount);
+
+		// Suggested trade timeout (minutes)
+		assert dataByteBuffer.position() == addrTradeTimeout * MachineState.VALUE_SIZE : "addrTradeTimeout incorrect";
+		dataByteBuffer.putLong(tradeTimeout);
+
+		// We're only interested in MESSAGE transactions
+		assert dataByteBuffer.position() == addrMessageTxnType * MachineState.VALUE_SIZE : "addrMessageTxnType incorrect";
+		dataByteBuffer.putLong(API.ATTransactionType.MESSAGE.value);
+
+		// Expected length of 'trade' MESSAGE data from AT creator
+		assert dataByteBuffer.position() == addrExpectedTradeMessageLength * MachineState.VALUE_SIZE : "addrExpectedTradeMessageLength incorrect";
+		dataByteBuffer.putLong(TRADE_MESSAGE_LENGTH);
+
+		// Expected length of 'redeem' MESSAGE data from trade partner
+		assert dataByteBuffer.position() == addrExpectedRedeemMessageLength * MachineState.VALUE_SIZE : "addrExpectedRedeemMessageLength incorrect";
+		dataByteBuffer.putLong(REDEEM_MESSAGE_LENGTH);
+
+		// Index into data segment of AT creator's address, used by GET_B_IND
+		assert dataByteBuffer.position() == addrCreatorAddressPointer * MachineState.VALUE_SIZE : "addrCreatorAddressPointer incorrect";
+		dataByteBuffer.putLong(addrCreatorAddress1);
+
+		// Index into data segment of partner's Qortal address, used by SET_B_IND
+		assert dataByteBuffer.position() == addrQortalPartnerAddressPointer * MachineState.VALUE_SIZE : "addrQortalPartnerAddressPointer incorrect";
+		dataByteBuffer.putLong(addrQortalPartnerAddress1);
+
+		// Index into data segment of (temporary) transaction's sender's address, used by GET_B_IND
+		assert dataByteBuffer.position() == addrMessageSenderPointer * MachineState.VALUE_SIZE : "addrMessageSenderPointer incorrect";
+		dataByteBuffer.putLong(addrMessageSender1);
+
+		// Offset into 'trade' MESSAGE data payload for extracting partner's Litecoin PKH
+		assert dataByteBuffer.position() == addrTradeMessagePartnerLitecoinPKHOffset * MachineState.VALUE_SIZE : "addrTradeMessagePartnerLitecoinPKHOffset incorrect";
+		dataByteBuffer.putLong(32L);
+
+		// Index into data segment of partner's Litecoin PKH, used by GET_B_IND
+		assert dataByteBuffer.position() == addrPartnerLitecoinPKHPointer * MachineState.VALUE_SIZE : "addrPartnerLitecoinPKHPointer incorrect";
+		dataByteBuffer.putLong(addrPartnerLitecoinPKH);
+
+		// Offset into 'trade' MESSAGE data payload for extracting hash-of-secret-A
+		assert dataByteBuffer.position() == addrTradeMessageHashOfSecretAOffset * MachineState.VALUE_SIZE : "addrTradeMessageHashOfSecretAOffset incorrect";
+		dataByteBuffer.putLong(64L);
+
+		// Index into data segment to hash of secret A, used by GET_B_IND
+		assert dataByteBuffer.position() == addrHashOfSecretAPointer * MachineState.VALUE_SIZE : "addrHashOfSecretAPointer incorrect";
+		dataByteBuffer.putLong(addrHashOfSecretA);
+
+		// Offset into 'redeem' MESSAGE data payload for extracting Qortal receiving address
+		assert dataByteBuffer.position() == addrRedeemMessageReceivingAddressOffset * MachineState.VALUE_SIZE : "addrRedeemMessageReceivingAddressOffset incorrect";
+		dataByteBuffer.putLong(32L);
+
+		// Source location and length for hashing any passed secret
+		assert dataByteBuffer.position() == addrMessageDataPointer * MachineState.VALUE_SIZE : "addrMessageDataPointer incorrect";
+		dataByteBuffer.putLong(addrMessageData);
+		assert dataByteBuffer.position() == addrMessageDataLength * MachineState.VALUE_SIZE : "addrMessageDataLength incorrect";
+		dataByteBuffer.putLong(32L);
+
+		// Pointer into data segment of where to save partner's receiving Qortal address, used by GET_B_IND
+		assert dataByteBuffer.position() == addrPartnerReceivingAddressPointer * MachineState.VALUE_SIZE : "addrPartnerReceivingAddressPointer incorrect";
+		dataByteBuffer.putLong(addrPartnerReceivingAddress);
+
+		assert dataByteBuffer.position() == addrEndOfConstants * MachineState.VALUE_SIZE : "dataByteBuffer position not at end of constants";
+
+		// Code labels
+		Integer labelRefund = null;
+
+		Integer labelTradeTxnLoop = null;
+		Integer labelCheckTradeTxn = null;
+		Integer labelCheckCancelTxn = null;
+		Integer labelNotTradeNorCancelTxn = null;
+		Integer labelCheckNonRefundTradeTxn = null;
+		Integer labelTradeTxnExtract = null;
+		Integer labelRedeemTxnLoop = null;
+		Integer labelCheckRedeemTxn = null;
+		Integer labelCheckRedeemTxnSender = null;
+		Integer labelPayout = null;
+
+		ByteBuffer codeByteBuffer = ByteBuffer.allocate(768);
+
+		// Two-pass version
+		for (int pass = 0; pass < 2; ++pass) {
+			codeByteBuffer.clear();
+
+			try {
+				/* Initialization */
+
+				// Use AT creation 'timestamp' as starting point for finding transactions sent to AT
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_CREATION_TIMESTAMP, addrLastTxnTimestamp));
+
+				// Load B register with AT creator's address so we can save it into addrCreatorAddress1-4
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_CREATOR_INTO_B));
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrCreatorAddressPointer));
+
+				// Set restart position to after this opcode
+				codeByteBuffer.put(OpCode.SET_PCS.compile());
+
+				/* Loop, waiting for message from AT creator's trade address containing trade partner details, or AT owner's address to cancel offer */
+
+				/* Transaction processing loop */
+				labelTradeTxnLoop = codeByteBuffer.position();
+
+				/* Sleep until message arrives */
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.SLEEP_UNTIL_MESSAGE.value, addrLastTxnTimestamp));
+
+				// Find next transaction (if any) to this AT since the last one (referenced by addrLastTxnTimestamp)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PUT_TX_AFTER_TIMESTAMP_INTO_A, addrLastTxnTimestamp));
+				// If no transaction found, A will be zero. If A is zero, set addrResult to 1, otherwise 0.
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.CHECK_A_IS_ZERO, addrResult));
+				// If addrResult is zero (i.e. A is non-zero, transaction was found) then go check transaction
+				codeByteBuffer.put(OpCode.BZR_DAT.compile(addrResult, calcOffset(codeByteBuffer, labelCheckTradeTxn)));
+				// Stop and wait for next block
+				codeByteBuffer.put(OpCode.STP_IMD.compile());
+
+				/* Check transaction */
+				labelCheckTradeTxn = codeByteBuffer.position();
+
+				// Update our 'last found transaction's timestamp' using 'timestamp' from transaction
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TIMESTAMP_FROM_TX_IN_A, addrLastTxnTimestamp));
+				// Extract transaction type (message/payment) from transaction and save type in addrTxnType
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TYPE_FROM_TX_IN_A, addrTxnType));
+				// If transaction type is not MESSAGE type then go look for another transaction
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrTxnType, addrMessageTxnType, calcOffset(codeByteBuffer, labelTradeTxnLoop)));
+
+				/* Check transaction's sender. We're expecting AT creator's trade address for 'trade' message, or AT creator's own address for 'cancel' message. */
+
+				// Extract sender address from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_ADDRESS_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrMessageSender1 (as pointed to by addrMessageSenderPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrMessageSenderPointer));
+				// Compare each part of message sender's address with AT creator's trade address. If they don't match, check for cancel situation.
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender1, addrCreatorTradeAddress1, calcOffset(codeByteBuffer, labelCheckCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender2, addrCreatorTradeAddress2, calcOffset(codeByteBuffer, labelCheckCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender3, addrCreatorTradeAddress3, calcOffset(codeByteBuffer, labelCheckCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender4, addrCreatorTradeAddress4, calcOffset(codeByteBuffer, labelCheckCancelTxn)));
+				// Message sender's address matches AT creator's trade address so go process 'trade' message
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelCheckNonRefundTradeTxn == null ? 0 : labelCheckNonRefundTradeTxn));
+
+				/* Checking message sender for possible cancel message */
+				labelCheckCancelTxn = codeByteBuffer.position();
+
+				// Compare each part of message sender's address with AT creator's address. If they don't match, look for another transaction.
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender1, addrCreatorAddress1, calcOffset(codeByteBuffer, labelNotTradeNorCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender2, addrCreatorAddress2, calcOffset(codeByteBuffer, labelNotTradeNorCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender3, addrCreatorAddress3, calcOffset(codeByteBuffer, labelNotTradeNorCancelTxn)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender4, addrCreatorAddress4, calcOffset(codeByteBuffer, labelNotTradeNorCancelTxn)));
+				// Partner address is AT creator's address, so cancel offer and finish.
+				codeByteBuffer.put(OpCode.SET_VAL.compile(addrMode, AcctMode.CANCELLED.value));
+				// We're finished forever (finishing auto-refunds remaining balance to AT creator)
+				codeByteBuffer.put(OpCode.FIN_IMD.compile());
+
+				/* Not trade nor cancel message */
+				labelNotTradeNorCancelTxn = codeByteBuffer.position();
+
+				// Loop to find another transaction
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelTradeTxnLoop == null ? 0 : labelTradeTxnLoop));
+
+				/* Possible switch-to-trade-mode message */
+				labelCheckNonRefundTradeTxn = codeByteBuffer.position();
+
+				// Check 'trade' message we received has expected number of message bytes
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(QortalFunctionCode.GET_MESSAGE_LENGTH_FROM_TX_IN_A.value, addrMessageLength));
+				// If message length matches, branch to info extraction code
+				codeByteBuffer.put(OpCode.BEQ_DAT.compile(addrMessageLength, addrExpectedTradeMessageLength, calcOffset(codeByteBuffer, labelTradeTxnExtract)));
+				// Message length didn't match - go back to finding another 'trade' MESSAGE transaction
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelTradeTxnLoop == null ? 0 : labelTradeTxnLoop));
+
+				/* Extracting info from 'trade' MESSAGE transaction */
+				labelTradeTxnExtract = codeByteBuffer.position();
+
+				// Extract message from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_MESSAGE_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrQortalPartnerAddress1 (as pointed to by addrQortalPartnerAddressPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrQortalPartnerAddressPointer));
+
+				// Extract trade partner's Litecoin public key hash (PKH) from message into B
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.PUT_PARTIAL_MESSAGE_FROM_TX_IN_A_INTO_B.value, addrTradeMessagePartnerLitecoinPKHOffset));
+				// Store partner's Litecoin PKH (we only really use values from B1-B3)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrPartnerLitecoinPKHPointer));
+				// Extract AT trade timeout (minutes) (from B4)
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_B4, addrRefundTimeout));
+
+				// Grab next 32 bytes
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.PUT_PARTIAL_MESSAGE_FROM_TX_IN_A_INTO_B.value, addrTradeMessageHashOfSecretAOffset));
+
+				// Extract hash-of-secret-A (we only really use values from B1-B3)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrHashOfSecretAPointer));
+				// Extract lockTime-A (from B4)
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_B4, addrLockTimeA));
+
+				// Calculate trade timeout refund 'timestamp' by adding addrRefundTimeout minutes to this transaction's 'timestamp', then save into addrRefundTimestamp
+				codeByteBuffer.put(OpCode.EXT_FUN_RET_DAT_2.compile(FunctionCode.ADD_MINUTES_TO_TIMESTAMP, addrRefundTimestamp, addrLastTxnTimestamp, addrRefundTimeout));
+
+				/* We are in 'trade mode' */
+				codeByteBuffer.put(OpCode.SET_VAL.compile(addrMode, AcctMode.TRADING.value));
+
+				// Set restart position to after this opcode
+				codeByteBuffer.put(OpCode.SET_PCS.compile());
+
+				/* Loop, waiting for trade timeout or 'redeem' MESSAGE from Qortal trade partner */
+
+				// Fetch current block 'timestamp'
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_BLOCK_TIMESTAMP, addrBlockTimestamp));
+				// If we're not past refund 'timestamp' then look for next transaction
+				codeByteBuffer.put(OpCode.BLT_DAT.compile(addrBlockTimestamp, addrRefundTimestamp, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+				// We're past refund 'timestamp' so go refund everything back to AT creator
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelRefund == null ? 0 : labelRefund));
+
+				/* Transaction processing loop */
+				labelRedeemTxnLoop = codeByteBuffer.position();
+
+				// Find next transaction to this AT since the last one (if any)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PUT_TX_AFTER_TIMESTAMP_INTO_A, addrLastTxnTimestamp));
+				// If no transaction found, A will be zero. If A is zero, set addrComparator to 1, otherwise 0.
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.CHECK_A_IS_ZERO, addrResult));
+				// If addrResult is zero (i.e. A is non-zero, transaction was found) then go check transaction
+				codeByteBuffer.put(OpCode.BZR_DAT.compile(addrResult, calcOffset(codeByteBuffer, labelCheckRedeemTxn)));
+				// Stop and wait for next block
+				codeByteBuffer.put(OpCode.STP_IMD.compile());
+
+				/* Check transaction */
+				labelCheckRedeemTxn = codeByteBuffer.position();
+
+				// Update our 'last found transaction's timestamp' using 'timestamp' from transaction
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TIMESTAMP_FROM_TX_IN_A, addrLastTxnTimestamp));
+				// Extract transaction type (message/payment) from transaction and save type in addrTxnType
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TYPE_FROM_TX_IN_A, addrTxnType));
+				// If transaction type is not MESSAGE type then go look for another transaction
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrTxnType, addrMessageTxnType, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+
+				/* Check message payload length */
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(QortalFunctionCode.GET_MESSAGE_LENGTH_FROM_TX_IN_A.value, addrMessageLength));
+				// If message length matches, branch to sender checking code
+				codeByteBuffer.put(OpCode.BEQ_DAT.compile(addrMessageLength, addrExpectedRedeemMessageLength, calcOffset(codeByteBuffer, labelCheckRedeemTxnSender)));
+				// Message length didn't match - go back to finding another 'redeem' MESSAGE transaction
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelRedeemTxnLoop == null ? 0 : labelRedeemTxnLoop));
+
+				/* Check transaction's sender */
+				labelCheckRedeemTxnSender = codeByteBuffer.position();
+
+				// Extract sender address from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_ADDRESS_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrMessageSender1 (as pointed to by addrMessageSenderPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrMessageSenderPointer));
+				// Compare each part of transaction's sender's address with expected address. If they don't match, look for another transaction.
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender1, addrQortalPartnerAddress1, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender2, addrQortalPartnerAddress2, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender3, addrQortalPartnerAddress3, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender4, addrQortalPartnerAddress4, calcOffset(codeByteBuffer, labelRedeemTxnLoop)));
+
+				/* Check 'secret-A' in transaction's message */
+
+				// Extract secret-A from first 32 bytes of message from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_MESSAGE_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrMessageData (as pointed to by addrMessageDataPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrMessageDataPointer));
+				// Load B register with expected hash result (as pointed to by addrHashOfSecretAPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.SET_B_IND, addrHashOfSecretAPointer));
+				// Perform HASH160 using source data at addrMessageData. (Location and length specified via addrMessageDataPointer and addrMessageDataLength).
+				// Save the equality result (1 if they match, 0 otherwise) into addrResult.
+				codeByteBuffer.put(OpCode.EXT_FUN_RET_DAT_2.compile(FunctionCode.CHECK_HASH160_WITH_B, addrResult, addrMessageDataPointer, addrMessageDataLength));
+				// If hashes don't match, addrResult will be zero so go find another transaction
+				codeByteBuffer.put(OpCode.BNZ_DAT.compile(addrResult, calcOffset(codeByteBuffer, labelPayout)));
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelRedeemTxnLoop == null ? 0 : labelRedeemTxnLoop));
+
+				/* Success! Pay arranged amount to receiving address */
+				labelPayout = codeByteBuffer.position();
+
+				// Extract Qortal receiving address from next 32 bytes of message from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.PUT_PARTIAL_MESSAGE_FROM_TX_IN_A_INTO_B.value, addrRedeemMessageReceivingAddressOffset));
+				// Save B register into data segment starting at addrPartnerReceivingAddress (as pointed to by addrPartnerReceivingAddressPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrPartnerReceivingAddressPointer));
+				// Pay AT's balance to receiving address
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PAY_TO_ADDRESS_IN_B, addrQortAmount));
+				// Set redeemed mode
+				codeByteBuffer.put(OpCode.SET_VAL.compile(addrMode, AcctMode.REDEEMED.value));
+				// We're finished forever (finishing auto-refunds remaining balance to AT creator)
+				codeByteBuffer.put(OpCode.FIN_IMD.compile());
+
+				// Fall-through to refunding any remaining balance back to AT creator
+
+				/* Refund balance back to AT creator */
+				labelRefund = codeByteBuffer.position();
+
+				// Set refunded mode
+				codeByteBuffer.put(OpCode.SET_VAL.compile(addrMode, AcctMode.REFUNDED.value));
+				// We're finished forever (finishing auto-refunds remaining balance to AT creator)
+				codeByteBuffer.put(OpCode.FIN_IMD.compile());
+			} catch (CompilationException e) {
+				throw new IllegalStateException("Unable to compile LTC-QORT ACCT?", e);
+			}
+		}
+
+		codeByteBuffer.flip();
+
+		byte[] codeBytes = new byte[codeByteBuffer.limit()];
+		codeByteBuffer.get(codeBytes);
+
+		assert Arrays.equals(Crypto.digest(codeBytes), LitecoinACCTv3.CODE_BYTES_HASH)
+			: String.format("BTCACCT.CODE_BYTES_HASH mismatch: expected %s, actual %s", HashCode.fromBytes(CODE_BYTES_HASH), HashCode.fromBytes(Crypto.digest(codeBytes)));
+
+		final short ciyamAtVersion = 2;
+		final short numCallStackPages = 0;
+		final short numUserStackPages = 0;
+		final long minActivationAmount = 0L;
+
+		return MachineState.toCreationBytes(ciyamAtVersion, codeBytes, dataByteBuffer.array(), numCallStackPages, numUserStackPages, minActivationAmount);
+	}
+
+	/**
+	 * Returns CrossChainTradeData with useful info extracted from AT.
+	 */
+	@Override
+	public CrossChainTradeData populateTradeData(Repository repository, ATData atData) throws DataException {
+		ATStateData atStateData = repository.getATRepository().getLatestATState(atData.getATAddress());
+		return populateTradeData(repository, atData.getCreatorPublicKey(), atData.getCreation(), atStateData);
+	}
+
+	/**
+	 * Returns CrossChainTradeData with useful info extracted from AT.
+	 */
+	@Override
+	public CrossChainTradeData populateTradeData(Repository repository, ATStateData atStateData) throws DataException {
+		ATData atData = repository.getATRepository().fromATAddress(atStateData.getATAddress());
+		return populateTradeData(repository, atData.getCreatorPublicKey(), atData.getCreation(), atStateData);
+	}
+
+	/**
+	 * Returns CrossChainTradeData with useful info extracted from AT.
+	 */
+	public CrossChainTradeData populateTradeData(Repository repository, byte[] creatorPublicKey, long creationTimestamp, ATStateData atStateData) throws DataException {
+		byte[] addressBytes = new byte[25]; // for general use
+		String atAddress = atStateData.getATAddress();
+
+		CrossChainTradeData tradeData = new CrossChainTradeData();
+
+		tradeData.foreignBlockchain = SupportedBlockchain.LITECOIN.name();
+		tradeData.acctName = NAME;
+
+		tradeData.qortalAtAddress = atAddress;
+		tradeData.qortalCreator = Crypto.toAddress(creatorPublicKey);
+		tradeData.creationTimestamp = creationTimestamp;
+
+		Account atAccount = new Account(repository, atAddress);
+		tradeData.qortBalance = atAccount.getConfirmedBalance(Asset.QORT);
+
+		byte[] stateData = atStateData.getStateData();
+		ByteBuffer dataByteBuffer = ByteBuffer.wrap(stateData);
+		dataByteBuffer.position(MachineState.HEADER_LENGTH);
+
+		/* Constants */
+
+		// Skip creator's trade address
+		dataByteBuffer.get(addressBytes);
+		tradeData.qortalCreatorTradeAddress = Base58.encode(addressBytes);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - addressBytes.length);
+
+		// Creator's Litecoin/foreign public key hash
+		tradeData.creatorForeignPKH = new byte[20];
+		dataByteBuffer.get(tradeData.creatorForeignPKH);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - tradeData.creatorForeignPKH.length); // skip to 32 bytes
+
+		// We don't use secret-B
+		tradeData.hashOfSecretB = null;
+
+		// Redeem payout
+		tradeData.qortAmount = dataByteBuffer.getLong();
+
+		// Expected LTC amount
+		tradeData.expectedForeignAmount = dataByteBuffer.getLong();
+
+		// Trade timeout
+		tradeData.tradeTimeout = (int) dataByteBuffer.getLong();
+
+		// Skip MESSAGE transaction type
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip expected 'trade' message length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip expected 'redeem' message length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to creator's address
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to partner's Qortal trade address
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to message sender
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip 'trade' message data offset for partner's Litecoin PKH
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to partner's Litecoin PKH
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip 'trade' message data offset for hash-of-secret-A
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to hash-of-secret-A
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip 'redeem' message data offset for partner's Qortal receiving address
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to message data
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip message data length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to partner's receiving address
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		/* End of constants / begin variables */
+
+		// Skip AT creator's address
+		dataByteBuffer.position(dataByteBuffer.position() + 8 * 4);
+
+		// Partner's trade address (if present)
+		dataByteBuffer.get(addressBytes);
+		String qortalRecipient = Base58.encode(addressBytes);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - addressBytes.length);
+
+		// Potential lockTimeA (if in trade mode)
+		int lockTimeA = (int) dataByteBuffer.getLong();
+
+		// AT refund timeout (probably only useful for debugging)
+		int refundTimeout = (int) dataByteBuffer.getLong();
+
+		// Trade-mode refund timestamp (AT 'timestamp' converted to Qortal block height)
+		long tradeRefundTimestamp = dataByteBuffer.getLong();
+
+		// Skip last transaction timestamp
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip block timestamp
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip transaction type
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip temporary result
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip temporary message sender
+		dataByteBuffer.position(dataByteBuffer.position() + 8 * 4);
+
+		// Skip message length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip temporary message data
+		dataByteBuffer.position(dataByteBuffer.position() + 8 * 4);
+
+		// Potential hash160 of secret A
+		byte[] hashOfSecretA = new byte[20];
+		dataByteBuffer.get(hashOfSecretA);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - hashOfSecretA.length); // skip to 32 bytes
+
+		// Potential partner's Litecoin PKH
+		byte[] partnerLitecoinPKH = new byte[20];
+		dataByteBuffer.get(partnerLitecoinPKH);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - partnerLitecoinPKH.length); // skip to 32 bytes
+
+		// Partner's receiving address (if present)
+		byte[] partnerReceivingAddress = new byte[25];
+		dataByteBuffer.get(partnerReceivingAddress);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - partnerReceivingAddress.length); // skip to 32 bytes
+
+		// Trade AT's 'mode'
+		long modeValue = dataByteBuffer.getLong();
+		AcctMode mode = AcctMode.valueOf((int) (modeValue & 0xffL));
+
+		/* End of variables */
+
+		if (mode != null && mode != AcctMode.OFFERING) {
+			tradeData.mode = mode;
+			tradeData.refundTimeout = refundTimeout;
+			tradeData.tradeRefundHeight = new Timestamp(tradeRefundTimestamp).blockHeight;
+			tradeData.qortalPartnerAddress = qortalRecipient;
+			tradeData.hashOfSecretA = hashOfSecretA;
+			tradeData.partnerForeignPKH = partnerLitecoinPKH;
+			tradeData.lockTimeA = lockTimeA;
+
+			if (mode == AcctMode.REDEEMED)
+				tradeData.qortalPartnerReceivingAddress = Base58.encode(partnerReceivingAddress);
+		} else {
+			tradeData.mode = AcctMode.OFFERING;
+		}
+
+		tradeData.duplicateDeprecated();
+
+		return tradeData;
+	}
+
+	/** Returns 'offer' MESSAGE payload for trade partner to send to AT creator's trade address. */
+	public static byte[] buildOfferMessage(byte[] partnerBitcoinPKH, byte[] hashOfSecretA, int lockTimeA) {
+		byte[] lockTimeABytes = BitTwiddling.toBEByteArray((long) lockTimeA);
+		return Bytes.concat(partnerBitcoinPKH, hashOfSecretA, lockTimeABytes);
+	}
+
+	/** Returns info extracted from 'offer' MESSAGE payload sent by trade partner to AT creator's trade address, or null if not valid. */
+	public static OfferMessageData extractOfferMessageData(byte[] messageData) {
+		if (messageData == null || messageData.length != OFFER_MESSAGE_LENGTH)
+			return null;
+
+		OfferMessageData offerMessageData = new OfferMessageData();
+		offerMessageData.partnerLitecoinPKH = Arrays.copyOfRange(messageData, 0, 20);
+		offerMessageData.hashOfSecretA = Arrays.copyOfRange(messageData, 20, 40);
+		offerMessageData.lockTimeA = BitTwiddling.longFromBEBytes(messageData, 40);
+
+		return offerMessageData;
+	}
+
+	/** Returns 'trade' MESSAGE payload for AT creator to send to AT. */
+	public static byte[] buildTradeMessage(String partnerQortalTradeAddress, byte[] partnerBitcoinPKH, byte[] hashOfSecretA, int lockTimeA, int refundTimeout) {
+		byte[] data = new byte[TRADE_MESSAGE_LENGTH];
+		byte[] partnerQortalAddressBytes = Base58.decode(partnerQortalTradeAddress);
+		byte[] lockTimeABytes = BitTwiddling.toBEByteArray((long) lockTimeA);
+		byte[] refundTimeoutBytes = BitTwiddling.toBEByteArray((long) refundTimeout);
+
+		System.arraycopy(partnerQortalAddressBytes, 0, data, 0, partnerQortalAddressBytes.length);
+		System.arraycopy(partnerBitcoinPKH, 0, data, 32, partnerBitcoinPKH.length);
+		System.arraycopy(refundTimeoutBytes, 0, data, 56, refundTimeoutBytes.length);
+		System.arraycopy(hashOfSecretA, 0, data, 64, hashOfSecretA.length);
+		System.arraycopy(lockTimeABytes, 0, data, 88, lockTimeABytes.length);
+
+		return data;
+	}
+
+	/** Returns 'cancel' MESSAGE payload for AT creator to cancel trade AT. */
+	@Override
+	public byte[] buildCancelMessage(String creatorQortalAddress) {
+		byte[] data = new byte[CANCEL_MESSAGE_LENGTH];
+		byte[] creatorQortalAddressBytes = Base58.decode(creatorQortalAddress);
+
+		System.arraycopy(creatorQortalAddressBytes, 0, data, 0, creatorQortalAddressBytes.length);
+
+		return data;
+	}
+
+	/** Returns 'redeem' MESSAGE payload for trade partner to send to AT. */
+	public static byte[] buildRedeemMessage(byte[] secretA, String qortalReceivingAddress) {
+		byte[] data = new byte[REDEEM_MESSAGE_LENGTH];
+		byte[] qortalReceivingAddressBytes = Base58.decode(qortalReceivingAddress);
+
+		System.arraycopy(secretA, 0, data, 0, secretA.length);
+		System.arraycopy(qortalReceivingAddressBytes, 0, data, 32, qortalReceivingAddressBytes.length);
+
+		return data;
+	}
+
+	/** Returns refund timeout (minutes) based on trade partner's 'offer' MESSAGE timestamp and P2SH-A locktime. */
+	public static int calcRefundTimeout(long offerMessageTimestamp, int lockTimeA) {
+		// refund should be triggered halfway between offerMessageTimestamp and lockTimeA
+		return (int) ((lockTimeA - (offerMessageTimestamp / 1000L)) / 2L / 60L);
+	}
+
+	@Override
+	public byte[] findSecretA(Repository repository, CrossChainTradeData crossChainTradeData) throws DataException {
+		String atAddress = crossChainTradeData.qortalAtAddress;
+		String redeemerAddress = crossChainTradeData.qortalPartnerAddress;
+
+		// We don't have partner's public key so we check every message to AT
+		List<MessageTransactionData> messageTransactionsData = repository.getMessageRepository().getMessagesByParticipants(null, atAddress, null, null, null);
+		if (messageTransactionsData == null)
+			return null;
+
+		// Find 'redeem' message
+		for (MessageTransactionData messageTransactionData : messageTransactionsData) {
+			// Check message payload type/encryption
+			if (messageTransactionData.isText() || messageTransactionData.isEncrypted())
+				continue;
+
+			// Check message payload size
+			byte[] messageData = messageTransactionData.getData();
+			if (messageData.length != REDEEM_MESSAGE_LENGTH)
+				// Wrong payload length
+				continue;
+
+			// Check sender
+			if (!Crypto.toAddress(messageTransactionData.getSenderPublicKey()).equals(redeemerAddress))
+				// Wrong sender;
+				continue;
+
+			// Extract secretA
+			byte[] secretA = new byte[32];
+			System.arraycopy(messageData, 0, secretA, 0, secretA.length);
+
+			byte[] hashOfSecretA = Crypto.hash160(secretA);
+			if (!Arrays.equals(hashOfSecretA, crossChainTradeData.hashOfSecretA))
+				continue;
+
+			return secretA;
+		}
+
+		return null;
+	}
+
+}

src/main/java/org/qortal/crosschain/SupportedBlockchain.java

@@ -28,7 +28,9 @@ public enum SupportedBlockchain {
 	},
 
 	LITECOIN(Arrays.asList(
-			Triple.valueOf(LitecoinACCTv1.NAME, LitecoinACCTv1.CODE_BYTES_HASH, LitecoinACCTv1::getInstance)
+			Triple.valueOf(LitecoinACCTv1.NAME, LitecoinACCTv1.CODE_BYTES_HASH, LitecoinACCTv1::getInstance),
+			Triple.valueOf(LitecoinACCTv2.NAME, LitecoinACCTv2.CODE_BYTES_HASH, LitecoinACCTv2::getInstance),
+			Triple.valueOf(LitecoinACCTv3.NAME, LitecoinACCTv3.CODE_BYTES_HASH, LitecoinACCTv3::getInstance)
 		)) {
 		@Override
 		public ForeignBlockchain getInstance() {
@@ -37,12 +39,14 @@ public enum SupportedBlockchain {
 
 		@Override
 		public ACCT getLatestAcct() {
-			return LitecoinACCTv1.getInstance();
+			return LitecoinACCTv3.getInstance();
 		}
 	},
 
 	DOGECOIN(Arrays.asList(
-			Triple.valueOf(DogecoinACCTv1.NAME, DogecoinACCTv1.CODE_BYTES_HASH, DogecoinACCTv1::getInstance)
+			Triple.valueOf(DogecoinACCTv1.NAME, DogecoinACCTv1.CODE_BYTES_HASH, DogecoinACCTv1::getInstance),
+			Triple.valueOf(DogecoinACCTv2.NAME, DogecoinACCTv2.CODE_BYTES_HASH, DogecoinACCTv2::getInstance),
+			Triple.valueOf(DogecoinACCTv3.NAME, DogecoinACCTv3.CODE_BYTES_HASH, DogecoinACCTv3::getInstance)
 		)) {
 		@Override
 		public ForeignBlockchain getInstance() {
@@ -51,7 +55,7 @@ public enum SupportedBlockchain {
 
 		@Override
 		public ACCT getLatestAcct() {
-			return DogecoinACCTv1.getInstance();
+			return DogecoinACCTv3.getInstance();
 		}
 	};
 

src/main/java/org/qortal/crypto/Crypto.java

@@ -1,5 +1,8 @@
 package org.qortal.crypto;
 
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
@@ -75,12 +78,74 @@ public abstract class Crypto {
 		return digest(digest(input));
 	}
 
+	/**
+	 * Returns 32-byte SHA-256 digest of file passed in input.
+	 *
+	 * @param file
+	 *            file in which to perform digest
+	 * @return byte[32] digest, or null if SHA-256 algorithm can't be accessed
+	 *
+	 * @throws IOException if the file cannot be read
+	 */
+	public static byte[] digest(File file) throws IOException {
+		return Crypto.digest(file, 8192);
+	}
+
+	/**
+	 * Returns 32-byte SHA-256 digest of file passed in input, in hex format
+	 *
+	 * @param file
+	 *            file in which to perform digest
+	 * @return String digest as a hexadecimal string, or null if SHA-256 algorithm can't be accessed
+	 *
+	 * @throws IOException if the file cannot be read
+	 */
+	public static String digestHexString(File file, int bufferSize) throws IOException {
+		byte[] digest = Crypto.digest(file, bufferSize);
+
+		// Convert to hex
+		StringBuilder stringBuilder = new StringBuilder();
+		for (byte b : digest) {
+			stringBuilder.append(String.format("%02x", b));
+		}
+		return stringBuilder.toString();
+	}
+
+	/**
+	 * Returns 32-byte SHA-256 digest of file passed in input.
+	 *
+	 * @param file
+	 *            file in which to perform digest
+	 * @param bufferSize
+	 * 			  the number of bytes to load into memory
+	 * @return byte[32] digest, or null if SHA-256 algorithm can't be accessed
+	 *
+	 * @throws IOException if the file cannot be read
+	 */
+	public static byte[] digest(File file, int bufferSize) throws IOException {
+		try {
+			MessageDigest sha256 = MessageDigest.getInstance("SHA-256");
+			FileInputStream fileInputStream = new FileInputStream(file);
+			byte[] bytes = new byte[bufferSize];
+			int count;
+
+			while ((count = fileInputStream.read(bytes)) != -1) {
+				sha256.update(bytes, 0, count);
+			}
+			fileInputStream.close();
+
+			return sha256.digest();
+
+		} catch (NoSuchAlgorithmException e) {
+			throw new RuntimeException("SHA-256 message digest not available");
+		}
+	}
+
 	/**
 	 * Returns 64-byte duplicated digest of message passed in input.
 	 * <p>
 	 * Effectively <tt>Bytes.concat(digest(input), digest(input)).
-	 * 
-	 * @param addressVersion
+	 *
 	 * @param input
 	 */
 	public static byte[] dupDigest(byte[] input) {

src/main/java/org/qortal/data/account/MintingAccountData.java

@@ -4,10 +4,12 @@ import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
 import javax.xml.bind.annotation.XmlTransient;
 
+import org.json.JSONObject;
 import org.qortal.crypto.Crypto;
 
 import io.swagger.v3.oas.annotations.media.Schema;
 import io.swagger.v3.oas.annotations.media.Schema.AccessMode;
+import org.qortal.utils.Base58;
 
 // All properties to be converted to JSON via JAXB
 @XmlAccessorType(XmlAccessType.FIELD)
@@ -61,4 +63,21 @@ public class MintingAccountData {
 		return this.publicKey;
 	}
 
+
+	// JSON
+
+	public JSONObject toJson() {
+		JSONObject jsonObject = new JSONObject();
+		jsonObject.put("privateKey", Base58.encode(this.getPrivateKey()));
+		jsonObject.put("publicKey", Base58.encode(this.getPublicKey()));
+		return jsonObject;
+	}
+
+	public static MintingAccountData fromJson(JSONObject json) {
+		return new MintingAccountData(
+				json.isNull("privateKey") ? null : Base58.decode(json.getString("privateKey")),
+				json.isNull("publicKey") ? null : Base58.decode(json.getString("publicKey"))
+		);
+	}
+
 }

src/main/java/org/qortal/data/block/BlockArchiveData.java

@@ -0,0 +1,47 @@
+package org.qortal.data.block;
+
+import org.qortal.block.Block;
+
+public class BlockArchiveData {
+
+	// Properties
+	private byte[] signature;
+	private Integer height;
+	private Long timestamp;
+	private byte[] minterPublicKey;
+
+	// Constructors
+
+	public BlockArchiveData(byte[] signature, Integer height, long timestamp, byte[] minterPublicKey) {
+		this.signature = signature;
+		this.height = height;
+		this.timestamp = timestamp;
+		this.minterPublicKey = minterPublicKey;
+	}
+
+	public BlockArchiveData(BlockData blockData) {
+		this.signature = blockData.getSignature();
+		this.height = blockData.getHeight();
+		this.timestamp = blockData.getTimestamp();
+		this.minterPublicKey = blockData.getMinterPublicKey();
+	}
+
+	// Getters/setters
+
+	public byte[] getSignature() {
+		return this.signature;
+	}
+
+	public Integer getHeight() {
+		return this.height;
+	}
+
+	public Long getTimestamp() {
+		return this.timestamp;
+	}
+
+	public byte[] getMinterPublicKey() {
+		return this.minterPublicKey;
+	}
+
+}

src/main/java/org/qortal/data/block/BlockData.java

@@ -204,6 +204,10 @@ public class BlockData implements Serializable {
 		return this.onlineAccountsSignatures;
 	}
 
+	public void setOnlineAccountsSignatures(byte[] onlineAccountsSignatures) {
+		this.onlineAccountsSignatures = onlineAccountsSignatures;
+	}
+
 	// JAXB special
 
 	@XmlElement(name = "minterAddress")

src/main/java/org/qortal/data/network/OnlineAccountLevel.java

@@ -0,0 +1,55 @@
+package org.qortal.data.network;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+
+
+// All properties to be converted to JSON via JAXB
+@XmlAccessorType(XmlAccessType.FIELD)
+public class OnlineAccountLevel {
+
+	protected int level;
+	protected int count;
+
+	// Constructors
+
+	// necessary for JAXB serialization
+	protected OnlineAccountLevel() {
+	}
+
+	public OnlineAccountLevel(int level, int count) {
+		this.level = level;
+		this.count = count;
+	}
+
+	public int getLevel() {
+		return this.level;
+	}
+
+	public int getCount() {
+		return this.count;
+	}
+
+	public void setCount(int count) {
+		this.count = count;
+	}
+
+
+	// Comparison
+
+	@Override
+	public boolean equals(Object other) {
+		if (other == this)
+			return true;
+
+		if (!(other instanceof OnlineAccountLevel))
+			return false;
+
+		OnlineAccountLevel otherOnlineAccountData = (OnlineAccountLevel) other;
+
+		if (otherOnlineAccountData.level != this.level)
+			return false;
+
+		return true;
+	}
+}

src/main/java/org/qortal/data/transaction/RegisterNameTransactionData.java

@@ -26,7 +26,7 @@ public class RegisterNameTransactionData extends TransactionData {
 	@Schema(description = "requested name", example = "my-name")
 	private String name;
 
-	@Schema(description = "simple name-related info in JSON format", example = "{ \"age\": 30 }")
+	@Schema(description = "simple name-related info in JSON or text format", example = "Registered Name on the Qortal Chain")
 	private String data;
 
 	// For internal use

src/main/java/org/qortal/data/transaction/UpdateNameTransactionData.java

@@ -26,7 +26,7 @@ public class UpdateNameTransactionData extends TransactionData {
 	@Schema(description = "new name", example = "my-new-name")
 	private String newName;
 
-	@Schema(description = "replacement simple name-related info in JSON format", example = "{ \"age\": 30 }")
+	@Schema(description = "replacement simple name-related info in JSON or text format", example = "Registered Name on the Qortal Chain")
 	private String newData;
 
 	// For internal use

src/main/java/org/qortal/gui/Gui.java

@@ -23,17 +23,21 @@ public class Gui {
 	private SysTray sysTray = null;
 
 	private Gui() {
-		this.isHeadless = GraphicsEnvironment.isHeadless();
+		try {
+			this.isHeadless = GraphicsEnvironment.isHeadless();
 
-		if (!this.isHeadless) {
-			try {
-				UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
-			} catch (ClassNotFoundException | InstantiationException | IllegalAccessException
-					| UnsupportedLookAndFeelException e) {
-				// Use whatever look-and-feel comes by default then
+			if (!this.isHeadless) {
+				try {
+					UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
+				} catch (ClassNotFoundException | InstantiationException | IllegalAccessException
+						| UnsupportedLookAndFeelException e) {
+					// Use whatever look-and-feel comes by default then
+				}
+
+				showSplash();
 			}
-
-			showSplash();
+		} catch (Exception e) {
+			LOGGER.info("Unable to initialize GUI: {}", e.getMessage());
 		}
 	}
 

src/main/java/org/qortal/gui/SplashFrame.java

@@ -6,9 +6,11 @@ import java.util.List;
 import java.awt.image.BufferedImage;
 
 import javax.swing.*;
+import javax.swing.border.EmptyBorder;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.qortal.controller.Controller;
 
 public class SplashFrame {
 
@@ -16,6 +18,7 @@ public class SplashFrame {
 
 	private static SplashFrame instance;
 	private JFrame splashDialog;
+	private SplashPanel splashPanel;
 
 	@SuppressWarnings("serial")
 	public static class SplashPanel extends JPanel {
@@ -23,26 +26,53 @@ public class SplashFrame {
 
 		private String defaultSplash = "Qlogo_512.png";
 
+		private JLabel statusLabel;
+
 		public SplashPanel() {
 			image = Gui.loadImage(defaultSplash);
 
-			setOpaque(false);
-			setLayout(new GridBagLayout());
-		}
+			setOpaque(true);
+			setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
+			setBorder(new EmptyBorder(10, 10, 10, 10));
+			setBackground(Color.BLACK);
 
-		@Override
-		protected void paintComponent(Graphics g) {
-			super.paintComponent(g);
-			g.drawImage(image, 0, 0, getWidth(), getHeight(), this);
+			// Add logo
+			JLabel imageLabel = new JLabel(new ImageIcon(image));
+			imageLabel.setSize(new Dimension(300, 300));
+			add(imageLabel);
+
+			// Add spacing
+			add(Box.createRigidArea(new Dimension(0, 16)));
+
+			// Add status label
+			String text = String.format("Starting Qortal Core v%s...", Controller.getInstance().getVersionStringWithoutPrefix());
+			statusLabel = new JLabel(text, JLabel.CENTER);
+			statusLabel.setMaximumSize(new Dimension(500, 50));
+			statusLabel.setFont(new Font("Verdana", Font.PLAIN, 20));
+			statusLabel.setBackground(Color.BLACK);
+			statusLabel.setForeground(new Color(255, 255, 255, 255));
+			statusLabel.setOpaque(true);
+			statusLabel.setBorder(null);
+			add(statusLabel);
 		}
 
 		@Override
 		public Dimension getPreferredSize() {
-			return new Dimension(500, 500);
+			return new Dimension(500, 580);
+		}
+
+		public void updateStatus(String text) {
+			if (statusLabel != null) {
+				statusLabel.setText(text);
+			}
 		}
 	}
 
 	private SplashFrame() {
+		if (GraphicsEnvironment.isHeadless()) {
+			return;
+		}
+
 		this.splashDialog = new JFrame();
 
 		List<Image> icons = new ArrayList<>();
@@ -55,12 +85,13 @@ public class SplashFrame {
 		icons.add(Gui.loadImage("icons/Qlogo_128.png"));
 		this.splashDialog.setIconImages(icons);
 
-		this.splashDialog.getContentPane().add(new SplashPanel());
+		this.splashPanel = new SplashPanel();
+		this.splashDialog.getContentPane().add(this.splashPanel);
 		this.splashDialog.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
 		this.splashDialog.setUndecorated(true);
 		this.splashDialog.pack();
 		this.splashDialog.setLocationRelativeTo(null);
-		this.splashDialog.setBackground(new Color(0,0,0,0));
+		this.splashDialog.setBackground(Color.BLACK);
 		this.splashDialog.setVisible(true);
 	}
 
@@ -79,4 +110,10 @@ public class SplashFrame {
 		this.splashDialog.dispose();
 	}
 
+	public void updateStatus(String text) {
+		if (this.splashPanel != null) {
+			this.splashPanel.updateStatus(text);
+		}
+	}
+
 }

src/main/java/org/qortal/gui/SysTray.java

@@ -291,19 +291,23 @@ public class SysTray {
 
 	public void setTrayIcon(int iconid) {
 		if (trayIcon != null) {
-			switch (iconid) {
-				case 1:
-					this.trayIcon.setImage(Gui.loadImage("icons/qortal_ui_tray_syncing_time-alt.png"));
-					break;
-				case 2:
-					this.trayIcon.setImage(Gui.loadImage("icons/qortal_ui_tray_minting.png"));
-					break;
-				case 3:
-					this.trayIcon.setImage(Gui.loadImage("icons/qortal_ui_tray_syncing.png"));
-					break;
-				case 4:
-					this.trayIcon.setImage(Gui.loadImage("icons/qortal_ui_tray_synced.png"));
-					break;
+			try {
+				switch (iconid) {
+					case 1:
+						this.trayIcon.setImage(Gui.loadImage("icons/qortal_ui_tray_syncing_time-alt.png"));
+						break;
+					case 2:
+						this.trayIcon.setImage(Gui.loadImage("icons/qortal_ui_tray_minting.png"));
+						break;
+					case 3:
+						this.trayIcon.setImage(Gui.loadImage("icons/qortal_ui_tray_syncing.png"));
+						break;
+					case 4:
+						this.trayIcon.setImage(Gui.loadImage("icons/qortal_ui_tray_synced.png"));
+						break;
+				}
+			} catch (NullPointerException e) {
+				LOGGER.info("Unable to set tray icon");
 			}
 		}
 	}

src/main/java/org/qortal/list/ResourceList.java

@@ -21,7 +21,7 @@ public class ResourceList {
 
     private String category;
     private String resourceName;
-    private List<String> list;
+    private List<String> list = new ArrayList<>();
 
     /**
      * ResourceList
@@ -44,14 +44,8 @@ public class ResourceList {
 
     private Path getFilePath() {
         String pathString = String.format("%s%s%s_%s.json", Settings.getInstance().getListsPath(),
-                File.separator, this.resourceName, this.category);
-        Path outputFilePath = Paths.get(pathString);
-        try {
-            Files.createDirectories(outputFilePath.getParent());
-        } catch (IOException e) {
-            throw new IllegalStateException("Unable to create lists directory");
-        }
-        return outputFilePath;
+                File.separator, this.category, this.resourceName);
+        return Paths.get(pathString);
     }
 
     public void save() throws IOException {
@@ -62,8 +56,15 @@ public class ResourceList {
             throw new IllegalStateException("Can't save list with missing category");
         }
         String jsonString = ResourceList.listToJSONString(this.list);
-
         Path filePath = this.getFilePath();
+
+        // Create parent directory if needed
+        try {
+            Files.createDirectories(filePath.getParent());
+        } catch (IOException e) {
+            throw new IllegalStateException("Unable to create lists directory");
+        }
+
         BufferedWriter writer = new BufferedWriter(new FileWriter(filePath.toString()));
         writer.write(jsonString);
         writer.close();
@@ -99,24 +100,35 @@ public class ResourceList {
     /* List management */
 
     public void add(String resource) {
+        if (resource == null || this.list == null) {
+            return;
+        }
         if (!this.contains(resource)) {
             this.list.add(resource);
         }
     }
 
     public void remove(String resource) {
+        if (resource == null || this.list == null) {
+            return;
+        }
         this.list.remove(resource);
     }
 
     public boolean contains(String resource) {
+        if (resource == null || this.list == null) {
+            return false;
+        }
         return this.list.contains(resource);
     }
 
 
-
     /* Utils */
 
     public static String listToJSONString(List<String> list) {
+        if (list == null) {
+            return null;
+        }
         JSONArray items = new JSONArray();
         for (String item : list) {
             items.put(item);
@@ -125,6 +137,9 @@ public class ResourceList {
     }
 
     private static List<String> listFromJSONString(String jsonString) {
+        if (jsonString == null) {
+            return null;
+        }
         JSONArray jsonList = new JSONArray(jsonString);
         List<String> resourceList = new ArrayList<>();
         for (int i=0; i<jsonList.length(); i++) {
@@ -134,4 +149,20 @@ public class ResourceList {
         return resourceList;
     }
 
+    public String getJSONString() {
+        return ResourceList.listToJSONString(this.list);
+    }
+
+    public String getCategory() {
+        return this.category;
+    }
+
+    public String getResourceName() {
+        return this.resourceName;
+    }
+
+    public String toString() {
+        return String.format("%s %s", this.category, this.resourceName);
+    }
+
 }

src/main/java/org/qortal/list/ResourceListManager.java

@@ -4,84 +4,125 @@ import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
 
 public class ResourceListManager {
 
     private static final Logger LOGGER = LogManager.getLogger(ResourceListManager.class);
 
     private static ResourceListManager instance;
-    private ResourceList addressBlacklist;
+    private List<ResourceList> lists = new ArrayList<>();
+
 
     public ResourceListManager() {
-        try {
-            this.addressBlacklist = new ResourceList("blacklist", "address");
-        } catch (IOException e) {
-            LOGGER.info("Error while loading address blacklist. Blocking is currently unavailable.");
-        }
     }
 
     public static synchronized ResourceListManager getInstance() {
         if (instance == null) {
             instance = new ResourceListManager();
         }
-
         return instance;
     }
 
-    public boolean addAddressToBlacklist(String address, boolean save) {
-        try {
-            this.addressBlacklist.add(address);
-            if (save) {
-                this.addressBlacklist.save();
+    private ResourceList getList(String category, String resourceName) {
+        for (ResourceList list : this.lists) {
+            if (Objects.equals(list.getCategory(), category) &&
+                    Objects.equals(list.getResourceName(), resourceName)) {
+                return list;
             }
-            return true;
-
-        } catch (IllegalStateException | IOException e) {
-            LOGGER.info("Unable to add address to blacklist", e);
-            return false;
         }
-    }
 
-    public boolean removeAddressFromBlacklist(String address, boolean save) {
+        // List doesn't exist in array yet, so create it
+        // This will load any existing data from the filesystem
         try {
-            this.addressBlacklist.remove(address);
+            ResourceList list = new ResourceList(category, resourceName);
+            this.lists.add(list);
+            return list;
 
-            if (save) {
-                this.addressBlacklist.save();
-            }
-            return true;
-
-        } catch (IllegalStateException | IOException e) {
-            LOGGER.info("Unable to remove address from blacklist", e);
-            return false;
-        }
-    }
-
-    public boolean isAddressInBlacklist(String address) {
-        if (this.addressBlacklist == null) {
-            return false;
-        }
-        return this.addressBlacklist.contains(address);
-    }
-
-    public void saveBlacklist() {
-        if (this.addressBlacklist == null) {
-            return;
-        }
-
-        try {
-            this.addressBlacklist.save();
         } catch (IOException e) {
-            LOGGER.info("Unable to save blacklist - reverting back to last saved state");
-            this.addressBlacklist.revert();
+            LOGGER.info("Unable to load or create list {} {}: {}", category, resourceName, e.getMessage());
+            return null;
+        }
+
+    }
+
+    public boolean addToList(String category, String resourceName, String item, boolean save) {
+        ResourceList list = this.getList(category, resourceName);
+        if (list == null) {
+            return false;
+        }
+
+        try {
+            list.add(item);
+            if (save) {
+                list.save();
+            }
+            return true;
+
+        } catch (IllegalStateException | IOException e) {
+            LOGGER.info(String.format("Unable to add item %s to list %s", item, list), e);
+            return false;
         }
     }
 
-    public void revertBlacklist() {
-        if (this.addressBlacklist == null) {
+    public boolean removeFromList(String category, String resourceName, String item, boolean save) {
+        ResourceList list = this.getList(category, resourceName);
+        if (list == null) {
+            return false;
+        }
+
+        try {
+            list.remove(item);
+
+            if (save) {
+                list.save();
+            }
+            return true;
+
+        } catch (IllegalStateException | IOException e) {
+            LOGGER.info(String.format("Unable to remove item %s from list %s", item, list), e);
+            return false;
+        }
+    }
+
+    public boolean listContains(String category, String resourceName, String address) {
+        ResourceList list = this.getList(category, resourceName);
+        if (list == null) {
+            return false;
+        }
+        return list.contains(address);
+    }
+
+    public void saveList(String category, String resourceName) {
+        ResourceList list = this.getList(category, resourceName);
+        if (list == null) {
             return;
         }
-        this.addressBlacklist.revert();
+
+        try {
+            list.save();
+        } catch (IOException e) {
+            LOGGER.info("Unable to save list {} - reverting back to last saved state", list);
+            list.revert();
+        }
+    }
+
+    public void revertList(String category, String resourceName) {
+        ResourceList list = this.getList(category, resourceName);
+        if (list == null) {
+            return;
+        }
+        list.revert();
+    }
+
+    public String getJSONStringForList(String category, String resourceName) {
+        ResourceList list = this.getList(category, resourceName);
+        if (list == null) {
+            return null;
+        }
+        return list.getJSONString();
     }
 
 }

src/main/java/org/qortal/naming/Name.java

@@ -78,9 +78,10 @@ public class Name {
 		// Set name's last-updated timestamp
 		this.nameData.setUpdated(updateNameTransactionData.getTimestamp());
 
-		// Update name and data where appropriate
+		// Update name, reduced name, and data where appropriate
 		if (!updateNameTransactionData.getNewName().isEmpty()) {
 			this.nameData.setName(updateNameTransactionData.getNewName());
+			this.nameData.setReducedName(updateNameTransactionData.getReducedNewName());
 
 			// If we're changing the name, we need to delete old entry
 			this.repository.getNameRepository().delete(updateNameTransactionData.getName());
@@ -106,6 +107,9 @@ public class Name {
 		// We can find previous 'name' from update transaction
 		this.nameData.setName(updateNameTransactionData.getName());
 
+		// We can derive the previous 'reduced name' from the previous name
+		this.nameData.setReducedName(Unicode.sanitize(updateNameTransactionData.getName()));
+
 		// We might need to hunt for previous data value
 		if (!updateNameTransactionData.getNewData().isEmpty())
 			this.nameData.setData(findPreviousData(nameReference));
@@ -261,4 +265,8 @@ public class Name {
 		return previousTransactionData.getTimestamp();
 	}
 
+	public NameData getNameData() {
+		return this.nameData;
+	}
+
 }

src/main/java/org/qortal/network/Network.java

@@ -73,7 +73,9 @@ public class Network {
             "node1.qortal.org", "node2.qortal.org", "node3.qortal.org", "node4.qortal.org", "node5.qortal.org",
             "node6.qortal.org", "node7.qortal.org", "node8.qortal.org", "node9.qortal.org", "node10.qortal.org",
             "node.qortal.ru", "node2.qortal.ru", "node3.qortal.ru", "node.qortal.uk", "node22.qortal.org",
-            "cinfu1.crowetic.com", "node.cwd.systems"
+            "cinfu1.crowetic.com", "node.cwd.systems", "bootstrap.cwd.systems", "node1.qortalnodes.live",
+            "node2.qortalnodes.live", "node3.qortalnodes.live", "node4.qortalnodes.live", "node5.qortalnodes.live",
+            "node6.qortalnodes.live", "node7.qortalnodes.live", "node8.qortalnodes.live"
     };
 
     private static final long NETWORK_EPC_KEEPALIVE = 10L; // seconds
@@ -155,9 +157,23 @@ public class Network {
         }
 
         // Load all known peers from repository
-        try (Repository repository = RepositoryManager.getRepository()) {
-            synchronized (this.allKnownPeers) {
-                this.allKnownPeers.addAll(repository.getNetworkRepository().getAllPeers());
+        synchronized (this.allKnownPeers) { List<String> fixedNetwork = Settings.getInstance().getFixedNetwork();
+            if (fixedNetwork != null && !fixedNetwork.isEmpty()) {
+                Long addedWhen = NTP.getTime();
+                String addedBy = "fixedNetwork";
+                List<PeerAddress> peerAddresses = new ArrayList<>();
+                for (String address : fixedNetwork) {
+                    PeerAddress peerAddress = PeerAddress.fromString(address);
+                    peerAddresses.add(peerAddress);
+                }
+                List<PeerData> peers = peerAddresses.stream()
+                        .map(peerAddress -> new PeerData(peerAddress, addedWhen, addedBy))
+                        .collect(Collectors.toList());
+                this.allKnownPeers.addAll(peers);
+            } else {
+                try (Repository repository = RepositoryManager.getRepository()) {
+                    this.allKnownPeers.addAll(repository.getNetworkRepository().getAllPeers());
+                }
             }
         }
 
@@ -513,14 +529,24 @@ public class Network {
         if (socketChannel == null) {
             return;
         }
+        PeerAddress address = PeerAddress.fromSocket(socketChannel.socket());
+        List<String> fixedNetwork = Settings.getInstance().getFixedNetwork();
+        if (fixedNetwork != null && !fixedNetwork.isEmpty() && ipNotInFixedList(address, fixedNetwork)) {
+            try {
+                LOGGER.debug("Connection discarded from peer {} as not in the fixed network list", address);
+                socketChannel.close();
+            } catch (IOException e) {
+                // IGNORE
+            }
+            return;
+        }
 
         final Long now = NTP.getTime();
         Peer newPeer;
 
         try {
             if (now == null) {
-                LOGGER.debug("Connection discarded from peer {} due to lack of NTP sync",
-                        PeerAddress.fromSocket(socketChannel.socket()));
+                LOGGER.debug("Connection discarded from peer {} due to lack of NTP sync", address);
                 socketChannel.close();
                 return;
             }
@@ -528,12 +554,12 @@ public class Network {
             synchronized (this.connectedPeers) {
                 if (connectedPeers.size() >= maxPeers) {
                     // We have enough peers
-                    LOGGER.debug("Connection discarded from peer {}", PeerAddress.fromSocket(socketChannel.socket()));
+                    LOGGER.debug("Connection discarded from peer {} because the server is full", address);
                     socketChannel.close();
                     return;
                 }
 
-                LOGGER.debug("Connection accepted from peer {}", PeerAddress.fromSocket(socketChannel.socket()));
+                LOGGER.debug("Connection accepted from peer {}", address);
 
                 newPeer = new Peer(socketChannel, channelSelector);
                 this.connectedPeers.add(newPeer);
@@ -541,6 +567,7 @@ public class Network {
         } catch (IOException e) {
             if (socketChannel.isOpen()) {
                 try {
+                    LOGGER.debug("Connection failed from peer {} while connecting/closing", address);
                     socketChannel.close();
                 } catch (IOException ce) {
                     // Couldn't close?
@@ -552,6 +579,16 @@ public class Network {
         this.onPeerReady(newPeer);
     }
 
+    private boolean ipNotInFixedList(PeerAddress address, List<String> fixedNetwork) {
+        for (String ipAddress : fixedNetwork) {
+            String[] bits = ipAddress.split(":");
+            if (bits.length >= 1 && bits.length <= 2 && address.getHost().equals(bits[0])) {
+                return false;
+            }
+        }
+        return true;
+    }
+
     private Peer getConnectablePeer(final Long now) throws InterruptedException {
         // We can't block here so use tryRepository(). We don't NEED to connect a new peer.
         try (Repository repository = RepositoryManager.tryRepository()) {
@@ -653,7 +690,7 @@ public class Network {
 
         if (peersToDisconnect != null && peersToDisconnect.size() > 0) {
             for (Peer peer : peersToDisconnect) {
-                LOGGER.info("Forcing disconnection of peer {} because connection age ({} ms) " +
+                LOGGER.debug("Forcing disconnection of peer {} because connection age ({} ms) " +
                         "has reached the maximum ({} ms)", peer, peer.getConnectionAge(), peer.getMaxConnectionAge());
                 peer.disconnect("Connection age too old");
             }
@@ -1145,6 +1182,10 @@ public class Network {
 
     private boolean mergePeers(Repository repository, String addedBy, long addedWhen, List<PeerAddress> peerAddresses)
             throws DataException {
+        List<String> fixedNetwork = Settings.getInstance().getFixedNetwork();
+        if (fixedNetwork != null && !fixedNetwork.isEmpty()) {
+            return false;
+        }
         List<PeerData> newPeers;
         synchronized (this.allKnownPeers) {
             for (PeerData knownPeerData : this.allKnownPeers) {

src/main/java/org/qortal/network/message/CachedBlockMessage.java

@@ -23,7 +23,7 @@ public class CachedBlockMessage extends Message {
 		this.block = block;
 	}
 
-	private CachedBlockMessage(byte[] cachedBytes) {
+	public CachedBlockMessage(byte[] cachedBytes) {
 		super(MessageType.BLOCK);
 
 		this.block = null;

src/main/java/org/qortal/repository/ATRepository.java

@@ -1,5 +1,7 @@
 package org.qortal.repository;
 
+import java.sql.ResultSet;
+import java.sql.SQLException;
 import java.util.List;
 import java.util.Set;
 
@@ -112,6 +114,14 @@ public interface ATRepository {
 	 */
 	public List<ATStateData> getBlockATStatesAtHeight(int height) throws DataException;
 
+
+	/** Rebuild the latest AT states cache, necessary for AT state trimming/pruning.
+	 * <p>
+	 * NOTE: performs implicit <tt>repository.saveChanges()</tt>.
+	 */
+	public void rebuildLatestAtStates() throws DataException;
+
+
 	/** Returns height of first trimmable AT state. */
 	public int getAtTrimHeight() throws DataException;
 
@@ -121,12 +131,27 @@ public interface ATRepository {
 	 */
 	public void setAtTrimHeight(int trimHeight) throws DataException;
 
-	/** Hook to allow repository to prepare/cache info for AT state trimming. */
-	public void prepareForAtStateTrimming() throws DataException;
-
 	/** Trims full AT state data between passed heights. Returns number of trimmed rows. */
 	public int trimAtStates(int minHeight, int maxHeight, int limit) throws DataException;
 
+
+	/** Returns height of first prunable AT state. */
+	public int getAtPruneHeight() throws DataException;
+
+	/** Sets new base height for AT state pruning.
+	 * <p>
+	 * NOTE: performs implicit <tt>repository.saveChanges()</tt>.
+	 */
+	public void setAtPruneHeight(int pruneHeight) throws DataException;
+
+	/** Prunes full AT state data between passed heights. Returns number of pruned rows. */
+	public int pruneAtStates(int minHeight, int maxHeight) throws DataException;
+
+
+	/** Checks for the presence of the ATStatesHeightIndex in repository */
+	public boolean hasAtStatesHeightIndex() throws DataException;
+
+
 	/**
 	 * Save ATStateData into repository.
 	 * <p>

src/main/java/org/qortal/repository/AccountRepository.java

@@ -191,6 +191,8 @@ public interface AccountRepository {
 
 	public List<MintingAccountData> getMintingAccounts() throws DataException;
 
+	public MintingAccountData getMintingAccount(byte[] mintingAccountKey) throws DataException;
+
 	public void save(MintingAccountData mintingAccountData) throws DataException;
 
 	/** Delete minting account info, used by BlockMinter, from repository using passed public or private key. */

src/main/java/org/qortal/repository/BlockArchiveReader.java

@@ -0,0 +1,284 @@
+package org.qortal.repository;
+
+import com.google.common.primitives.Ints;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.data.at.ATStateData;
+import org.qortal.data.block.BlockArchiveData;
+import org.qortal.data.block.BlockData;
+import org.qortal.data.transaction.TransactionData;
+import org.qortal.settings.Settings;
+import org.qortal.transform.TransformationException;
+import org.qortal.transform.block.BlockTransformer;
+import org.qortal.utils.Triple;
+
+import static org.qortal.transform.Transformer.INT_LENGTH;
+
+import java.io.*;
+import java.nio.ByteBuffer;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.*;
+
+public class BlockArchiveReader {
+
+    private static BlockArchiveReader instance;
+    private Map<String, Triple<Integer, Integer, Integer>> fileListCache = Collections.synchronizedMap(new HashMap<>());
+
+    private static final Logger LOGGER = LogManager.getLogger(BlockArchiveReader.class);
+
+    public BlockArchiveReader() {
+
+    }
+
+    public static synchronized BlockArchiveReader getInstance() {
+        if (instance == null) {
+            instance = new BlockArchiveReader();
+        }
+
+        return instance;
+    }
+
+    private void fetchFileList() {
+        Path archivePath = Paths.get(Settings.getInstance().getRepositoryPath(), "archive").toAbsolutePath();
+        File archiveDirFile = archivePath.toFile();
+        String[] files = archiveDirFile.list();
+        Map<String, Triple<Integer, Integer, Integer>> map = new HashMap<>();
+
+        if (files != null) {
+            for (String file : files) {
+                Path filePath = Paths.get(file);
+                String filename = filePath.getFileName().toString();
+
+                // Parse the filename
+                if (filename == null || !filename.contains("-") || !filename.contains(".")) {
+                    // Not a usable file
+                    continue;
+                }
+                // Remove the extension and split into two parts
+                String[] parts = filename.substring(0, filename.lastIndexOf('.')).split("-");
+                Integer startHeight = Integer.parseInt(parts[0]);
+                Integer endHeight = Integer.parseInt(parts[1]);
+                Integer range = endHeight - startHeight;
+                map.put(filename, new Triple(startHeight, endHeight, range));
+            }
+        }
+        this.fileListCache = map;
+    }
+
+    public Triple<BlockData, List<TransactionData>, List<ATStateData>> fetchBlockAtHeight(int height) {
+        if (this.fileListCache.isEmpty()) {
+            this.fetchFileList();
+        }
+
+        byte[] serializedBytes = this.fetchSerializedBlockBytesForHeight(height);
+        if (serializedBytes == null) {
+            return null;
+        }
+
+        ByteBuffer byteBuffer = ByteBuffer.wrap(serializedBytes);
+        Triple<BlockData, List<TransactionData>, List<ATStateData>> blockInfo = null;
+        try {
+            blockInfo = BlockTransformer.fromByteBuffer(byteBuffer);
+            if (blockInfo != null && blockInfo.getA() != null) {
+                // Block height is stored outside of the main serialized bytes, so it
+                // won't be set automatically.
+                blockInfo.getA().setHeight(height);
+            }
+        } catch (TransformationException e) {
+            return null;
+        }
+        return blockInfo;
+    }
+
+    public Triple<BlockData, List<TransactionData>, List<ATStateData>> fetchBlockWithSignature(
+            byte[] signature, Repository repository) {
+
+        if (this.fileListCache.isEmpty()) {
+            this.fetchFileList();
+        }
+
+        Integer height = this.fetchHeightForSignature(signature, repository);
+        if (height != null) {
+            return this.fetchBlockAtHeight(height);
+        }
+        return null;
+    }
+
+    public List<Triple<BlockData, List<TransactionData>, List<ATStateData>>> fetchBlocksFromRange(
+            int startHeight, int endHeight) {
+
+        List<Triple<BlockData, List<TransactionData>, List<ATStateData>>> blockInfoList = new ArrayList<>();
+
+        for (int height = startHeight; height <= endHeight; height++) {
+            Triple<BlockData, List<TransactionData>, List<ATStateData>> blockInfo = this.fetchBlockAtHeight(height);
+            if (blockInfo == null) {
+                return blockInfoList;
+            }
+            blockInfoList.add(blockInfo);
+        }
+        return blockInfoList;
+    }
+
+    public Integer fetchHeightForSignature(byte[] signature, Repository repository) {
+        // Lookup the height for the requested signature
+        try {
+            BlockArchiveData archivedBlock = repository.getBlockArchiveRepository().getBlockArchiveDataForSignature(signature);
+            if (archivedBlock == null) {
+                return null;
+            }
+            return archivedBlock.getHeight();
+
+        } catch (DataException e) {
+            return null;
+        }
+    }
+
+    public int fetchHeightForTimestamp(long timestamp, Repository repository) {
+        // Lookup the height for the requested signature
+        try {
+            return repository.getBlockArchiveRepository().getHeightFromTimestamp(timestamp);
+
+        } catch (DataException e) {
+            return 0;
+        }
+    }
+
+    private String getFilenameForHeight(int height) {
+        Iterator it = this.fileListCache.entrySet().iterator();
+        while (it.hasNext()) {
+            Map.Entry pair = (Map.Entry)it.next();
+            if (pair == null && pair.getKey() == null && pair.getValue() == null) {
+                continue;
+            }
+            Triple<Integer, Integer, Integer> heightInfo = (Triple<Integer, Integer, Integer>) pair.getValue();
+            Integer startHeight = heightInfo.getA();
+            Integer endHeight = heightInfo.getB();
+
+            if (height >= startHeight && height <= endHeight) {
+                // Found the correct file
+                String filename = (String) pair.getKey();
+                return filename;
+            }
+        }
+
+        return null;
+    }
+
+    public byte[] fetchSerializedBlockBytesForSignature(byte[] signature, boolean includeHeightPrefix, Repository repository) {
+
+        if (this.fileListCache.isEmpty()) {
+            this.fetchFileList();
+        }
+
+        Integer height = this.fetchHeightForSignature(signature, repository);
+        if (height != null) {
+            byte[] blockBytes = this.fetchSerializedBlockBytesForHeight(height);
+            if (blockBytes == null) {
+                return null;
+            }
+
+            // When responding to a peer with a BLOCK message, we must prefix the byte array with the block height
+            // This mimics the toData() method in BlockMessage and CachedBlockMessage
+            if (includeHeightPrefix) {
+                ByteArrayOutputStream bytes = new ByteArrayOutputStream(blockBytes.length + INT_LENGTH);
+                try {
+                    bytes.write(Ints.toByteArray(height));
+                    bytes.write(blockBytes);
+                    return bytes.toByteArray();
+
+                } catch (IOException e) {
+                    return null;
+                }
+            }
+            return blockBytes;
+        }
+        return null;
+    }
+
+    public byte[] fetchSerializedBlockBytesForHeight(int height) {
+        String filename = this.getFilenameForHeight(height);
+        if (filename == null) {
+            // We don't have this block in the archive
+            // Invalidate the file list cache in case it is out of date
+            this.invalidateFileListCache();
+            return null;
+        }
+
+        Path filePath = Paths.get(Settings.getInstance().getRepositoryPath(), "archive", filename).toAbsolutePath();
+        RandomAccessFile file = null;
+        try {
+            file = new RandomAccessFile(filePath.toString(), "r");
+            // Get info about this file (the "fixed length header")
+            final int version = file.readInt(); // Do not remove or comment out, as it is moving the file pointer
+            final int startHeight = file.readInt(); // Do not remove or comment out, as it is moving the file pointer
+            final int endHeight = file.readInt(); // Do not remove or comment out, as it is moving the file pointer
+            file.readInt(); // Block count (unused) // Do not remove or comment out, as it is moving the file pointer
+            final int variableHeaderLength = file.readInt(); // Do not remove or comment out, as it is moving the file pointer
+            final int fixedHeaderLength = (int)file.getFilePointer();
+            // End of fixed length header
+
+            // Make sure the version is one we recognize
+            if (version != 1) {
+                LOGGER.info("Error: unknown version in file {}: {}", filename, version);
+                return null;
+            }
+
+            // Verify that the block is within the reported range
+            if (height < startHeight || height > endHeight) {
+                LOGGER.info("Error: requested height {} but the range of file {} is {}-{}",
+                        height, filename, startHeight, endHeight);
+                return null;
+            }
+
+            // Seek to the location of the block index in the variable length header
+            final int locationOfBlockIndexInVariableHeaderSegment = (height - startHeight) * INT_LENGTH;
+            file.seek(fixedHeaderLength + locationOfBlockIndexInVariableHeaderSegment);
+
+            // Read the value to obtain the index of this block in the data segment
+            int locationOfBlockInDataSegment = file.readInt();
+
+            // Now seek to the block data itself
+            int dataSegmentStartIndex = fixedHeaderLength + variableHeaderLength + INT_LENGTH; // Confirmed correct
+            file.seek(dataSegmentStartIndex + locationOfBlockInDataSegment);
+
+            // Read the block metadata
+            int blockHeight = file.readInt(); // Do not remove or comment out, as it is moving the file pointer
+            int blockLength = file.readInt(); // Do not remove or comment out, as it is moving the file pointer
+
+            // Ensure the block height matches the one requested
+            if (blockHeight != height) {
+                LOGGER.info("Error: height {} does not match requested: {}", blockHeight, height);
+                return null;
+            }
+
+            // Now retrieve the block's serialized bytes
+            byte[] blockBytes = new byte[blockLength];
+            file.read(blockBytes);
+
+            return blockBytes;
+
+        } catch (FileNotFoundException e) {
+            LOGGER.info("File {} not found: {}", filename, e.getMessage());
+            return null;
+        } catch (IOException e) {
+            LOGGER.info("Unable to read block {} from archive: {}", height, e.getMessage());
+            return null;
+        }
+        finally {
+            // Close the file
+            if (file != null) {
+                try {
+                    file.close();
+                } catch (IOException e) {
+                    // Failed to close, but no need to handle this
+                }
+            }
+        }
+    }
+
+    public void invalidateFileListCache() {
+        this.fileListCache.clear();
+    }
+
+}

src/main/java/org/qortal/repository/BlockArchiveRepository.java

@@ -0,0 +1,139 @@
+package org.qortal.repository;
+
+import org.qortal.api.model.BlockSignerSummary;
+import org.qortal.data.block.BlockArchiveData;
+import org.qortal.data.block.BlockData;
+import org.qortal.data.block.BlockSummaryData;
+
+import java.util.List;
+
+public interface BlockArchiveRepository {
+
+    /**
+     * Returns BlockData from archive using block signature.
+     *
+     * @param signature
+     * @return block data, or null if not found in archive.
+     * @throws DataException
+     */
+    public BlockData fromSignature(byte[] signature) throws DataException;
+
+    /**
+     * Return height of block in archive using block's signature.
+     *
+     * @param signature
+     * @return height, or 0 if not found in blockchain.
+     * @throws DataException
+     */
+    public int getHeightFromSignature(byte[] signature) throws DataException;
+
+    /**
+     * Returns BlockData from archive using block height.
+     *
+     * @param height
+     * @return block data, or null if not found in blockchain.
+     * @throws DataException
+     */
+    public BlockData fromHeight(int height) throws DataException;
+
+    /**
+     * Returns a list of BlockData objects from archive using
+     * block height range.
+     *
+     * @param startHeight
+     * @return a list of BlockData objects, or an empty list if
+     * not found in blockchain. It is not guaranteed that all
+     * requested blocks will be returned.
+     * @throws DataException
+     */
+    public List<BlockData> fromRange(int startHeight, int endHeight) throws DataException;
+
+    /**
+     * Returns BlockData from archive using block reference.
+     * Currently relies on a child block being the one block
+     * higher than its parent. This limitation can be removed
+     * by storing the reference in the BlockArchive table, but
+     * this has been avoided to reduce space.
+     *
+     * @param reference
+     * @return block data, or null if either parent or child
+     * not found in the archive.
+     * @throws DataException
+     */
+    public BlockData fromReference(byte[] reference) throws DataException;
+
+    /**
+     * Return height of block with timestamp just before passed timestamp.
+     *
+     * @param timestamp
+     * @return height, or 0 if not found in blockchain.
+     * @throws DataException
+     */
+    public int getHeightFromTimestamp(long timestamp) throws DataException;
+
+    /**
+     * Returns block timestamp for a given height.
+     *
+     * @param height
+     * @return timestamp, or 0 if height is out of bounds.
+     * @throws DataException
+     */
+    public long getTimestampFromHeight(int height) throws DataException;
+
+    /**
+     * Returns block summaries for blocks signed by passed public key, or reward-share with minter with passed public key.
+     */
+    public List<BlockSummaryData> getBlockSummariesBySigner(byte[] signerPublicKey, Integer limit, Integer offset, Boolean reverse) throws DataException;
+
+    /**
+     * Returns summaries of block signers, optionally limited to passed addresses.
+     * This combines both the BlockArchive and the Blocks data into a single result set.
+     */
+    public List<BlockSignerSummary> getBlockSigners(List<String> addresses, Integer limit, Integer offset, Boolean reverse) throws DataException;
+
+
+    /** Returns height of first unarchived block. */
+    public int getBlockArchiveHeight() throws DataException;
+
+    /** Sets new height for block archiving.
+     * <p>
+     * NOTE: performs implicit <tt>repository.saveChanges()</tt>.
+     */
+    public void setBlockArchiveHeight(int archiveHeight) throws DataException;
+
+
+    /**
+     * Returns the block archive data for a given signature, from the block archive.
+     * <p>
+     * This method will return null if no block archive has been built for the
+     * requested signature. In those cases, the height (and other data) can be
+     * looked up using the Blocks table. This allows a block to be located in
+     * the archive when we only know its signature.
+     * <p>
+     *
+     * @param signature
+     * @throws DataException
+     */
+    public BlockArchiveData getBlockArchiveDataForSignature(byte[] signature) throws DataException;
+
+    /**
+     * Saves a block archive entry into the repository.
+     * <p>
+     * This can be used to find the height of a block by its signature, without
+     * having access to the block data itself.
+     * <p>
+     *
+     * @param blockArchiveData
+     * @throws DataException
+     */
+    public void save(BlockArchiveData blockArchiveData) throws DataException;
+
+    /**
+     * Deletes a block archive entry from the repository.
+     *
+     * @param blockArchiveData
+     * @throws DataException
+     */
+    public void delete(BlockArchiveData blockArchiveData) throws DataException;
+
+}

src/main/java/org/qortal/repository/BlockArchiveWriter.java

@@ -0,0 +1,201 @@
+package org.qortal.repository;
+
+import com.google.common.primitives.Ints;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.block.Block;
+import org.qortal.controller.Controller;
+import org.qortal.data.block.BlockArchiveData;
+import org.qortal.data.block.BlockData;
+import org.qortal.settings.Settings;
+import org.qortal.transform.TransformationException;
+import org.qortal.transform.block.BlockTransformer;
+
+import java.io.ByteArrayOutputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+public class BlockArchiveWriter {
+
+    public enum BlockArchiveWriteResult {
+        OK,
+        STOPPING,
+        NOT_ENOUGH_BLOCKS,
+        BLOCK_NOT_FOUND
+    }
+
+    private static final Logger LOGGER = LogManager.getLogger(BlockArchiveWriter.class);
+
+    public static final long DEFAULT_FILE_SIZE_TARGET = 100 * 1024 * 1024; // 100MiB
+
+    private int startHeight;
+    private final int endHeight;
+    private final Repository repository;
+
+    private long fileSizeTarget = DEFAULT_FILE_SIZE_TARGET;
+    private boolean shouldEnforceFileSizeTarget = true;
+
+    private int writtenCount;
+    private int lastWrittenHeight;
+    private Path outputPath;
+
+    public BlockArchiveWriter(int startHeight, int endHeight, Repository repository) {
+        this.startHeight = startHeight;
+        this.endHeight = endHeight;
+        this.repository = repository;
+    }
+
+    public static int getMaxArchiveHeight(Repository repository) throws DataException {
+        // We must only archive trimmed blocks, or the archive will grow far too large
+        final int accountSignaturesTrimStartHeight = repository.getBlockRepository().getOnlineAccountsSignaturesTrimHeight();
+        final int atTrimStartHeight = repository.getATRepository().getAtTrimHeight();
+        final int trimStartHeight = Math.min(accountSignaturesTrimStartHeight, atTrimStartHeight);
+        return trimStartHeight - 1; // subtract 1 because these values represent the first _untrimmed_ block
+    }
+
+    public static boolean isArchiverUpToDate(Repository repository) throws DataException {
+        final int maxArchiveHeight = BlockArchiveWriter.getMaxArchiveHeight(repository);
+        final int actualArchiveHeight = repository.getBlockArchiveRepository().getBlockArchiveHeight();
+        final float progress = (float)actualArchiveHeight / (float) maxArchiveHeight;
+        LOGGER.debug(String.format("maxArchiveHeight: %d, actualArchiveHeight: %d, progress: %f",
+                maxArchiveHeight, actualArchiveHeight, progress));
+
+        // If archiver is within 95% of the maximum, treat it as up to date
+        // We need several percent as an allowance because the archiver will only
+        // save files when they reach the target size
+        return (progress >= 0.95);
+    }
+
+    public BlockArchiveWriteResult write() throws DataException, IOException, TransformationException, InterruptedException {
+        // Create the archive folder if it doesn't exist
+        // This is a subfolder of the db directory, to make bootstrapping easier
+        Path archivePath = Paths.get(Settings.getInstance().getRepositoryPath(), "archive").toAbsolutePath();
+        try {
+            Files.createDirectories(archivePath);
+        } catch (IOException e) {
+            LOGGER.info("Unable to create archive folder");
+            throw new DataException("Unable to create archive folder");
+        }
+
+        // Determine start height of blocks to fetch
+        if (startHeight <= 2) {
+            // Skip genesis block, as it's not designed to be transmitted, and we can build that from blockchain.json
+            // TODO: include genesis block if we can
+            startHeight = 2;
+        }
+
+        // Header bytes will store the block indexes
+        ByteArrayOutputStream headerBytes = new ByteArrayOutputStream();
+        // Bytes will store the actual block data
+        ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+        LOGGER.info(String.format("Fetching blocks from height %d...", startHeight));
+        int i = 0;
+        while (headerBytes.size() + bytes.size() < this.fileSizeTarget
+                || this.shouldEnforceFileSizeTarget == false) {
+
+            if (Controller.isStopping()) {
+                return BlockArchiveWriteResult.STOPPING;
+            }
+            if (Controller.getInstance().isSynchronizing()) {
+                continue;
+            }
+
+            int currentHeight = startHeight + i;
+            if (currentHeight > endHeight) {
+                break;
+            }
+
+            //LOGGER.info("Fetching block {}...", currentHeight);
+
+            BlockData blockData = repository.getBlockRepository().fromHeight(currentHeight);
+            if (blockData == null) {
+                return BlockArchiveWriteResult.BLOCK_NOT_FOUND;
+            }
+
+            // Write the signature and height into the BlockArchive table
+            BlockArchiveData blockArchiveData = new BlockArchiveData(blockData);
+            repository.getBlockArchiveRepository().save(blockArchiveData);
+            repository.saveChanges();
+
+            // Write the block data to some byte buffers
+            Block block = new Block(repository, blockData);
+            int blockIndex = bytes.size();
+            // Write block index to header
+            headerBytes.write(Ints.toByteArray(blockIndex));
+            // Write block height
+            bytes.write(Ints.toByteArray(block.getBlockData().getHeight()));
+            byte[] blockBytes = BlockTransformer.toBytes(block);
+            // Write block length
+            bytes.write(Ints.toByteArray(blockBytes.length));
+            // Write block bytes
+            bytes.write(blockBytes);
+            i++;
+
+        }
+        int totalLength = headerBytes.size() + bytes.size();
+        LOGGER.info(String.format("Total length of %d blocks is %d bytes", i, totalLength));
+
+        // Validate file size, in case something went wrong
+        if (totalLength < fileSizeTarget && this.shouldEnforceFileSizeTarget) {
+            return BlockArchiveWriteResult.NOT_ENOUGH_BLOCKS;
+        }
+
+        // We have enough blocks to create a new file
+        int endHeight = startHeight + i - 1;
+        int version = 1;
+        String filePath = String.format("%s/%d-%d.dat", archivePath.toString(), startHeight, endHeight);
+        FileOutputStream fileOutputStream = new FileOutputStream(filePath);
+        // Write version number
+        fileOutputStream.write(Ints.toByteArray(version));
+        // Write start height
+        fileOutputStream.write(Ints.toByteArray(startHeight));
+        // Write end height
+        fileOutputStream.write(Ints.toByteArray(endHeight));
+        // Write total count
+        fileOutputStream.write(Ints.toByteArray(i));
+        // Write dynamic header (block indexes) segment length
+        fileOutputStream.write(Ints.toByteArray(headerBytes.size()));
+        // Write dynamic header (block indexes) data
+        headerBytes.writeTo(fileOutputStream);
+        // Write data segment (block data) length
+        fileOutputStream.write(Ints.toByteArray(bytes.size()));
+        // Write data
+        bytes.writeTo(fileOutputStream);
+        // Close the file
+        fileOutputStream.close();
+
+        // Invalidate cache so that the rest of the app picks up the new file
+        BlockArchiveReader.getInstance().invalidateFileListCache();
+
+        this.writtenCount = i;
+        this.lastWrittenHeight = endHeight;
+        this.outputPath = Paths.get(filePath);
+        return BlockArchiveWriteResult.OK;
+    }
+
+    public int getWrittenCount() {
+        return this.writtenCount;
+    }
+
+    public int getLastWrittenHeight() {
+        return this.lastWrittenHeight;
+    }
+
+    public Path getOutputPath() {
+        return this.outputPath;
+    }
+
+    public void setFileSizeTarget(long fileSizeTarget) {
+        this.fileSizeTarget = fileSizeTarget;
+    }
+
+    // For testing, to avoid having to pre-calculate file sizes
+    public void setShouldEnforceFileSizeTarget(boolean shouldEnforceFileSizeTarget) {
+        this.shouldEnforceFileSizeTarget = shouldEnforceFileSizeTarget;
+    }
+
+}

src/main/java/org/qortal/repository/BlockRepository.java

@@ -137,11 +137,6 @@ public interface BlockRepository {
 	 */
 	public List<BlockSummaryData> getBlockSummaries(int firstBlockHeight, int lastBlockHeight) throws DataException;
 
-	/**
-	 * Returns block summaries for the passed height range, for API use.
-	 */
-	public List<BlockSummaryData> getBlockSummaries(Integer startHeight, Integer endHeight, Integer count) throws DataException;
-
 	/** Returns height of first trimmable online accounts signatures. */
 	public int getOnlineAccountsSignaturesTrimHeight() throws DataException;
 
@@ -166,6 +161,20 @@ public interface BlockRepository {
 	 */
 	public BlockData getDetachedBlockSignature(int startHeight) throws DataException;
 
+
+	/** Returns height of first prunable block. */
+	public int getBlockPruneHeight() throws DataException;
+
+	/** Sets new base height for block pruning.
+	 * <p>
+	 * NOTE: performs implicit <tt>repository.saveChanges()</tt>.
+	 */
+	public void setBlockPruneHeight(int pruneHeight) throws DataException;
+
+	/** Prunes full block data between passed heights. Returns number of pruned rows. */
+	public int pruneBlocks(int minHeight, int maxHeight) throws DataException;
+
+
 	/**
 	 * Saves block into repository.
 	 * 

src/main/java/org/qortal/repository/Bootstrap.java

@@ -0,0 +1,513 @@
+package org.qortal.repository;
+
+import org.apache.commons.io.FileUtils;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.block.BlockChain;
+import org.qortal.controller.Controller;
+import org.qortal.crypto.Crypto;
+import org.qortal.data.account.MintingAccountData;
+import org.qortal.data.block.BlockData;
+import org.qortal.data.crosschain.TradeBotData;
+import org.qortal.gui.SplashFrame;
+import org.qortal.network.Network;
+import org.qortal.repository.hsqldb.HSQLDBImportExport;
+import org.qortal.repository.hsqldb.HSQLDBRepositoryFactory;
+import org.qortal.settings.Settings;
+import org.qortal.utils.NTP;
+import org.qortal.utils.SevenZ;
+
+import java.io.BufferedInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.nio.file.*;
+import java.security.SecureRandom;
+import java.util.List;
+import java.util.UUID;
+import java.util.concurrent.TimeoutException;
+import java.util.concurrent.locks.ReentrantLock;
+
+import static java.nio.file.StandardCopyOption.REPLACE_EXISTING;
+
+
+public class Bootstrap {
+
+    private Repository repository;
+
+    private int retryMinutes = 1;
+
+    private static final Logger LOGGER = LogManager.getLogger(Bootstrap.class);
+
+    /** The maximum number of untrimmed blocks allowed to be included in a bootstrap, beyond the trim threshold */
+    private static final int MAXIMUM_UNTRIMMED_BLOCKS = 100;
+
+    /** The maximum number of unpruned blocks allowed to be included in a bootstrap, beyond the prune threshold */
+    private static final int MAXIMUM_UNPRUNED_BLOCKS = 100;
+
+
+    public Bootstrap() {
+    }
+
+    public Bootstrap(Repository repository) {
+        this.repository = repository;
+    }
+
+    /**
+     * canCreateBootstrap()
+     * Performs basic initial checks to ensure everything is in order
+     * @return true if ready for bootstrap creation, or an exception if not
+     * All failure reasons are logged and included in the exception
+     * @throws DataException
+     */
+    public boolean checkRepositoryState() throws DataException {
+        LOGGER.info("Checking repository state...");
+
+        final boolean isTopOnly = Settings.getInstance().isTopOnly();
+        final boolean archiveEnabled = Settings.getInstance().isArchiveEnabled();
+
+        // Make sure we have a repository instance
+        if (repository == null) {
+            throw new DataException("Repository instance required to check if we can create a bootstrap.");
+        }
+
+        // Require that a block archive has been built
+        if (!isTopOnly && !archiveEnabled) {
+            throw new DataException("Unable to create bootstrap because the block archive isn't enabled. " +
+                    "Set {\"archivedEnabled\": true} in settings.json to fix.");
+        }
+
+        // Make sure that the block archiver is up to date
+        boolean upToDate = BlockArchiveWriter.isArchiverUpToDate(repository);
+        if (!upToDate) {
+            throw new DataException("Unable to create bootstrap because the block archive isn't fully built yet.");
+        }
+
+        // Ensure that this database contains the ATStatesHeightIndex which was missing in some cases
+        boolean hasAtStatesHeightIndex = repository.getATRepository().hasAtStatesHeightIndex();
+        if (!hasAtStatesHeightIndex) {
+            throw new DataException("Unable to create bootstrap due to missing ATStatesHeightIndex. A re-sync from genesis is needed.");
+        }
+
+        // Ensure we have synced NTP time
+        if (NTP.getTime() == null) {
+            throw new DataException("Unable to create bootstrap because the node hasn't synced its time yet.");
+        }
+
+        // Ensure the chain is synced
+        final BlockData chainTip = Controller.getInstance().getChainTip();
+        final Long minLatestBlockTimestamp = Controller.getMinimumLatestBlockTimestamp();
+        if (minLatestBlockTimestamp == null || chainTip.getTimestamp() < minLatestBlockTimestamp) {
+            throw new DataException("Unable to create bootstrap because the blockchain isn't fully synced.");
+        }
+
+        // FUTURE: ensure trim and prune settings are using default values
+
+        if (!isTopOnly) {
+            // We don't trim in top-only mode because we prune the blocks instead
+            // If we're not in top-only mode we should make sure that trimming is up to date
+
+            // Ensure that the online account signatures have been fully trimmed
+            final int accountsTrimStartHeight = repository.getBlockRepository().getOnlineAccountsSignaturesTrimHeight();
+            final long accountsUpperTrimmableTimestamp = NTP.getTime() - BlockChain.getInstance().getOnlineAccountSignaturesMaxLifetime();
+            final int accountsUpperTrimmableHeight = repository.getBlockRepository().getHeightFromTimestamp(accountsUpperTrimmableTimestamp);
+            final int accountsBlocksRemaining = accountsUpperTrimmableHeight - accountsTrimStartHeight;
+            if (accountsBlocksRemaining > MAXIMUM_UNTRIMMED_BLOCKS) {
+                throw new DataException(String.format("Blockchain is not fully trimmed. Please allow the node to run for longer, " +
+                        "then try again. Blocks remaining (online accounts signatures): %d", accountsBlocksRemaining));
+            }
+
+            // Ensure that the AT states data has been fully trimmed
+            final int atTrimStartHeight = repository.getATRepository().getAtTrimHeight();
+            final long atUpperTrimmableTimestamp = chainTip.getTimestamp() - Settings.getInstance().getAtStatesMaxLifetime();
+            final int atUpperTrimmableHeight = repository.getBlockRepository().getHeightFromTimestamp(atUpperTrimmableTimestamp);
+            final int atBlocksRemaining = atUpperTrimmableHeight - atTrimStartHeight;
+            if (atBlocksRemaining > MAXIMUM_UNTRIMMED_BLOCKS) {
+                throw new DataException(String.format("Blockchain is not fully trimmed. Please allow the node to run " +
+                        "for longer, then try again. Blocks remaining (AT states): %d", atBlocksRemaining));
+            }
+        }
+
+        // Ensure that blocks have been fully pruned
+        final int blockPruneStartHeight = repository.getBlockRepository().getBlockPruneHeight();
+        int blockUpperPrunableHeight = chainTip.getHeight() - Settings.getInstance().getPruneBlockLimit();
+        if (archiveEnabled) {
+            blockUpperPrunableHeight = repository.getBlockArchiveRepository().getBlockArchiveHeight() - 1;
+        }
+        final int blocksPruneRemaining = blockUpperPrunableHeight - blockPruneStartHeight;
+        if (blocksPruneRemaining > MAXIMUM_UNPRUNED_BLOCKS) {
+            throw new DataException(String.format("Blockchain is not fully pruned. Please allow the node to run " +
+                    "for longer, then try again. Blocks remaining: %d", blocksPruneRemaining));
+        }
+
+        // Ensure that AT states have been fully pruned
+        final int atPruneStartHeight = repository.getATRepository().getAtPruneHeight();
+        int atUpperPrunableHeight = chainTip.getHeight() - Settings.getInstance().getPruneBlockLimit();
+        if (archiveEnabled) {
+            atUpperPrunableHeight = repository.getBlockArchiveRepository().getBlockArchiveHeight() - 1;
+        }
+        final int atPruneRemaining = atUpperPrunableHeight - atPruneStartHeight;
+        if (atPruneRemaining > MAXIMUM_UNPRUNED_BLOCKS) {
+            throw new DataException(String.format("Blockchain is not fully pruned. Please allow the node to run " +
+                    "for longer, then try again. Blocks remaining (AT states): %d", atPruneRemaining));
+        }
+
+        LOGGER.info("Repository state checks passed");
+        return true;
+    }
+
+    /**
+     * validateBlockchain
+     * Performs quick validation of recent blocks in blockchain, prior to creating a bootstrap
+     * @return true if valid, an exception if not
+     * @throws DataException
+     */
+    public boolean validateBlockchain() throws DataException {
+        LOGGER.info("Validating blockchain...");
+
+        try {
+            BlockChain.validate();
+
+            LOGGER.info("Blockchain is valid");
+
+            return true;
+        } catch (DataException e) {
+            throw new DataException(String.format("Blockchain validation failed: %s", e.getMessage()));
+        }
+    }
+
+    /**
+     * validateCompleteBlockchain
+     * Performs intensive validation of all blocks in blockchain
+     * @return true if valid, false if not
+     */
+    public boolean validateCompleteBlockchain() {
+        LOGGER.info("Validating blockchain...");
+
+        try {
+            // Perform basic startup validation
+            BlockChain.validate();
+
+            // Perform more intensive full-chain validation
+            BlockChain.validateAllBlocks();
+
+            LOGGER.info("Blockchain is valid");
+
+            return true;
+        } catch (DataException e) {
+            LOGGER.info("Blockchain validation failed: {}", e.getMessage());
+            return false;
+        }
+    }
+
+    public String create() throws DataException, InterruptedException, IOException {
+
+        // Make sure we have a repository instance
+        if (repository == null) {
+            throw new DataException("Repository instance required in order to create a boostrap");
+        }
+
+        LOGGER.info("Deleting temp directory if it exists...");
+        this.deleteAllTempDirectories();
+
+        LOGGER.info("Acquiring blockchain lock...");
+        ReentrantLock blockchainLock = Controller.getInstance().getBlockchainLock();
+        blockchainLock.lockInterruptibly();
+
+        Path inputPath = null;
+        Path outputPath = null;
+
+        try {
+
+            LOGGER.info("Exporting local data...");
+            repository.exportNodeLocalData();
+
+            LOGGER.info("Deleting trade bot states...");
+            List<TradeBotData> allTradeBotData = repository.getCrossChainRepository().getAllTradeBotData();
+            for (TradeBotData tradeBotData : allTradeBotData) {
+                repository.getCrossChainRepository().delete(tradeBotData.getTradePrivateKey());
+            }
+
+            LOGGER.info("Deleting minting accounts...");
+            List<MintingAccountData> mintingAccounts = repository.getAccountRepository().getMintingAccounts();
+            for (MintingAccountData mintingAccount : mintingAccounts) {
+                repository.getAccountRepository().delete(mintingAccount.getPrivateKey());
+            }
+
+            repository.saveChanges();
+
+            LOGGER.info("Deleting peers list...");
+            repository.getNetworkRepository().deleteAllPeers();
+            repository.saveChanges();
+
+            LOGGER.info("Adding initial peers...");
+            Network.installInitialPeers(repository);
+
+            LOGGER.info("Creating bootstrap...");
+            // Timeout if the database isn't ready for backing up after 10 seconds
+            long timeout = 10 * 1000L;
+            repository.backup(false, "bootstrap", timeout);
+
+            LOGGER.info("Moving files to output directory...");
+            inputPath = Paths.get(Settings.getInstance().getRepositoryPath(), "bootstrap");
+            outputPath = Paths.get(this.createTempDirectory().toString(), "bootstrap");
+
+
+            // Move the db backup to a "bootstrap" folder in the root directory
+            Files.move(inputPath, outputPath, REPLACE_EXISTING);
+
+            // If in archive mode, copy the archive folder to inside the bootstrap folder
+            if (!Settings.getInstance().isTopOnly() && Settings.getInstance().isArchiveEnabled()) {
+                FileUtils.copyDirectory(
+                        Paths.get(Settings.getInstance().getRepositoryPath(), "archive").toFile(),
+                        Paths.get(outputPath.toString(), "archive").toFile()
+                );
+            }
+
+            LOGGER.info("Preparing output path...");
+            Path compressedOutputPath = this.getBootstrapOutputPath();
+            try {
+                Files.delete(compressedOutputPath);
+            } catch (NoSuchFileException e) {
+                // Doesn't exist, so no need to delete
+            }
+
+            LOGGER.info("Compressing...");
+            SevenZ.compress(compressedOutputPath.toString(), outputPath.toFile());
+
+            LOGGER.info("Generating checksum file...");
+            String checksum = Crypto.digestHexString(compressedOutputPath.toFile(), 1024*1024);
+            Path checksumPath = Paths.get(String.format("%s.sha256", compressedOutputPath.toString()));
+            Files.writeString(checksumPath, checksum, StandardOpenOption.CREATE);
+
+            // Return the path to the compressed bootstrap file
+            LOGGER.info("Bootstrap creation complete. Output file: {}", compressedOutputPath.toAbsolutePath().toString());
+            return compressedOutputPath.toAbsolutePath().toString();
+
+        }
+        catch (TimeoutException e) {
+            throw new DataException(String.format("Unable to create bootstrap due to timeout: %s", e.getMessage()));
+        }
+        finally {
+            try {
+                LOGGER.info("Re-importing local data...");
+                Path exportPath = HSQLDBImportExport.getExportDirectory(false);
+                repository.importDataFromFile(Paths.get(exportPath.toString(), "TradeBotStates.json").toString());
+                repository.importDataFromFile(Paths.get(exportPath.toString(), "MintingAccounts.json").toString());
+                repository.saveChanges();
+
+            } catch (IOException e) {
+                LOGGER.info("Unable to re-import local data, but created bootstrap is still valid. {}", e);
+            }
+
+            LOGGER.info("Unlocking blockchain...");
+            blockchainLock.unlock();
+
+            // Cleanup
+            LOGGER.info("Cleaning up...");
+            Thread.sleep(5000L);
+            this.deleteAllTempDirectories();
+        }
+    }
+
+    public void startImport() throws InterruptedException {
+        while (!Controller.isStopping()) {
+            try (final Repository repository = RepositoryManager.getRepository()) {
+                this.repository = repository;
+
+                this.updateStatus("Starting import of bootstrap...");
+
+                this.doImport();
+                break;
+
+            } catch (DataException e) {
+                LOGGER.info("Bootstrap import failed", e);
+                this.updateStatus(String.format("Bootstrapping failed. Retrying in %d minutes...", retryMinutes));
+                Thread.sleep(retryMinutes * 60 * 1000L);
+                retryMinutes *= 2;
+            }
+        }
+    }
+
+    private void doImport() throws DataException {
+        Path path = null;
+        try {
+            Path tempDir = this.createTempDirectory();
+            String filename = String.format("%s%s", Settings.getInstance().getBootstrapFilenamePrefix(), this.getFilename());
+            path = Paths.get(tempDir.toString(), filename);
+
+            this.downloadToPath(path);
+            this.importFromPath(path);
+
+        } catch (InterruptedException | DataException | IOException e) {
+            throw new DataException("Unable to import bootstrap", e);
+        }
+        finally {
+            if (path != null) {
+                try {
+                    Files.delete(path);
+
+                } catch (IOException e) {
+                    // Temp folder will be cleaned up below, so ignore this failure
+                }
+            }
+            this.deleteAllTempDirectories();
+        }
+    }
+
+    private String getFilename() {
+        boolean isTopOnly = Settings.getInstance().isTopOnly();
+        boolean archiveEnabled = Settings.getInstance().isArchiveEnabled();
+        boolean isTestnet = Settings.getInstance().isTestNet();
+        String prefix = isTestnet ? "testnet-" : "";
+
+        if (isTopOnly) {
+            return prefix.concat("bootstrap-toponly.7z");
+        }
+        else if (archiveEnabled) {
+            return prefix.concat("bootstrap-archive.7z");
+        }
+        else {
+            return prefix.concat("bootstrap-full.7z");
+        }
+    }
+
+    private void downloadToPath(Path path) throws DataException {
+        String bootstrapHost = this.getRandomHost();
+        String bootstrapFilename = this.getFilename();
+        String bootstrapUrl = String.format("%s/%s", bootstrapHost, bootstrapFilename);
+        String type = Settings.getInstance().isTopOnly() ? "top-only" : "full node";
+
+        SplashFrame.getInstance().updateStatus(String.format("Downloading %s bootstrap...", type));
+        LOGGER.info(String.format("Downloading %s bootstrap from %s ...", type, bootstrapUrl));
+
+        // Delete an existing file if it exists
+        try {
+            Files.delete(path);
+        } catch (IOException e) {
+            // No need to do anything
+        }
+
+        // Get the total file size
+        URL url;
+        long fileSize;
+        try {
+            url = new URL(bootstrapUrl);
+            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+            connection.setRequestMethod("HEAD");
+            connection.connect();
+            fileSize = connection.getContentLengthLong();
+            connection.disconnect();
+
+        } catch (MalformedURLException e) {
+            throw new DataException(String.format("Malformed URL when downloading bootstrap: %s", e.getMessage()));
+        } catch (IOException e) {
+            throw new DataException(String.format("Unable to get bootstrap file size from %s. " +
+                    "Please check your internet connection.", e.getMessage()));
+        }
+
+        // Download the file and update the status with progress
+        try (BufferedInputStream in = new BufferedInputStream(url.openStream());
+             FileOutputStream fileOutputStream = new FileOutputStream(path.toFile())) {
+            byte[] buffer = new byte[1024 * 1024];
+            long downloaded = 0;
+            int bytesRead;
+            while ((bytesRead = in.read(buffer, 0, 1024)) != -1) {
+                fileOutputStream.write(buffer, 0, bytesRead);
+                downloaded += bytesRead;
+
+                if (fileSize > 0) {
+                    int progress = (int)((double)downloaded / (double)fileSize * 100);
+                    SplashFrame.getInstance().updateStatus(String.format("Downloading %s bootstrap... (%d%%)", type, progress));
+                }
+            }
+
+        } catch (IOException e) {
+            throw new DataException(String.format("Unable to download bootstrap: %s", e.getMessage()));
+        }
+    }
+
+    public String getRandomHost() {
+        // Select a random host from bootstrapHosts
+        String[] hosts = Settings.getInstance().getBootstrapHosts();
+        int index = new SecureRandom().nextInt(hosts.length);
+        String bootstrapHost = hosts[index];
+        return bootstrapHost;
+    }
+
+    public void importFromPath(Path path) throws InterruptedException, DataException, IOException {
+
+        ReentrantLock blockchainLock = Controller.getInstance().getBlockchainLock();
+        blockchainLock.lockInterruptibly();
+
+        try {
+            this.updateStatus("Stopping repository...");
+            // Close the repository while we are still able to
+            // Otherwise, the caller will run into difficulties when it tries to close it
+            repository.discardChanges();
+            repository.close();
+            // Now close the repository factory so that we can swap out the database files
+            RepositoryManager.closeRepositoryFactory();
+
+            this.updateStatus("Deleting existing repository...");
+            Path input = path.toAbsolutePath();
+            Path output = path.toAbsolutePath().getParent().toAbsolutePath();
+            Path inputPath = Paths.get(output.toString(), "bootstrap");
+            Path outputPath = Paths.get(Settings.getInstance().getRepositoryPath());
+            FileUtils.deleteDirectory(outputPath.toFile());
+
+            this.updateStatus("Extracting bootstrap...");
+            SevenZ.decompress(input.toString(), output.toFile());
+
+            if (!inputPath.toFile().exists()) {
+                throw new DataException("Extracted bootstrap doesn't exist");
+            }
+
+            // Move the "bootstrap" folder in place of the "db" folder
+            this.updateStatus("Moving files to output directory...");
+            Files.move(inputPath, outputPath);
+
+            this.updateStatus("Starting repository from bootstrap...");
+        }
+        finally {
+            RepositoryFactory repositoryFactory = new HSQLDBRepositoryFactory(Controller.getRepositoryUrl());
+            RepositoryManager.setRepositoryFactory(repositoryFactory);
+
+            blockchainLock.unlock();
+        }
+    }
+
+    private Path createTempDirectory() throws IOException {
+        Path initialPath = Paths.get(Settings.getInstance().getRepositoryPath()).toAbsolutePath().getParent();
+        String baseDir = Paths.get(initialPath.toString(), "tmp").toFile().getCanonicalPath();
+        String identifier = UUID.randomUUID().toString();
+        Path tempDir = Paths.get(baseDir, identifier);
+        Files.createDirectories(tempDir);
+        return tempDir;
+    }
+
+    private void deleteAllTempDirectories() {
+        Path initialPath = Paths.get(Settings.getInstance().getRepositoryPath()).toAbsolutePath().getParent();
+        Path path = Paths.get(initialPath.toString(), "tmp");
+        try {
+            FileUtils.deleteDirectory(path.toFile());
+        } catch (IOException e) {
+            LOGGER.info("Unable to delete temp directory path: {}", path.toString(), e);
+        }
+    }
+
+    public Path getBootstrapOutputPath() {
+        Path initialPath = Paths.get(Settings.getInstance().getRepositoryPath()).toAbsolutePath().getParent();
+        String compressedFilename = String.format("%s%s", Settings.getInstance().getBootstrapFilenamePrefix(), this.getFilename());
+        Path compressedOutputPath = Paths.get(initialPath.toString(), compressedFilename);
+        return compressedOutputPath;
+    }
+
+    private void updateStatus(String text) {
+        LOGGER.info(text);
+        SplashFrame.getInstance().updateStatus(text);
+    }
+
+}

src/main/java/org/qortal/repository/Repository.java

@@ -1,5 +1,8 @@
 package org.qortal.repository;
 
+import java.io.IOException;
+import java.util.concurrent.TimeoutException;
+
 public interface Repository extends AutoCloseable {
 
 	public ATRepository getATRepository();
@@ -12,6 +15,8 @@ public interface Repository extends AutoCloseable {
 
 	public BlockRepository getBlockRepository();
 
+	public BlockArchiveRepository getBlockArchiveRepository();
+
 	public ChatRepository getChatRepository();
 
 	public CrossChainRepository getCrossChainRepository();
@@ -45,14 +50,16 @@ public interface Repository extends AutoCloseable {
 
 	public void setDebug(boolean debugState);
 
-	public void backup(boolean quick) throws DataException;
+	public void backup(boolean quick, String name, Long timeout) throws DataException, TimeoutException;
 
-	public void performPeriodicMaintenance() throws DataException;
+	public void performPeriodicMaintenance(Long timeout) throws DataException, TimeoutException;
 
 	public void exportNodeLocalData() throws DataException;
 
-	public void importDataFromFile(String filename) throws DataException;
+	public void importDataFromFile(String filename) throws DataException, IOException;
 
 	public void checkConsistency() throws DataException;
 
+	public static void attemptRecovery(String connectionUrl, String name) throws DataException {}
+
 }

src/main/java/org/qortal/repository/RepositoryManager.java

@@ -1,8 +1,18 @@
 package org.qortal.repository;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.gui.SplashFrame;
+import org.qortal.repository.hsqldb.HSQLDBDatabaseArchiving;
+import org.qortal.repository.hsqldb.HSQLDBDatabasePruning;
+import org.qortal.repository.hsqldb.HSQLDBRepository;
+import org.qortal.settings.Settings;
+
 import java.sql.SQLException;
+import java.util.concurrent.TimeoutException;
 
 public abstract class RepositoryManager {
+	private static final Logger LOGGER = LogManager.getLogger(RepositoryManager.class);
 
 	private static RepositoryFactory repositoryFactory = null;
 
@@ -43,14 +53,60 @@ public abstract class RepositoryManager {
 		repositoryFactory = null;
 	}
 
-	public static void backup(boolean quick) {
+	public static void backup(boolean quick, String name, Long timeout) throws TimeoutException {
 		try (final Repository repository = getRepository()) {
-			repository.backup(quick);
+			repository.backup(quick, name, timeout);
 		} catch (DataException e) {
 			// Backup is best-effort so don't complain
 		}
 	}
 
+	public static boolean archive(Repository repository) {
+		// Bulk archive the database the first time we use archive mode
+		if (Settings.getInstance().isArchiveEnabled()) {
+			if (RepositoryManager.canArchiveOrPrune()) {
+				try {
+					return HSQLDBDatabaseArchiving.buildBlockArchive(repository, BlockArchiveWriter.DEFAULT_FILE_SIZE_TARGET);
+
+				} catch (DataException e) {
+					LOGGER.info("Unable to build block archive. The database may have been left in an inconsistent state.");
+				}
+			}
+			else {
+				LOGGER.info("Unable to build block archive due to missing ATStatesHeightIndex. Bootstrapping is recommended.");
+				LOGGER.info("To bootstrap, stop the core and delete the db folder, then start the core again.");
+				SplashFrame.getInstance().updateStatus("Missing index. Bootstrapping is recommended.");
+			}
+		}
+		return false;
+	}
+
+	public static boolean prune(Repository repository) {
+		// Bulk prune the database the first time we use top-only or block archive mode
+		if (Settings.getInstance().isTopOnly() ||
+			Settings.getInstance().isArchiveEnabled()) {
+			if (RepositoryManager.canArchiveOrPrune()) {
+				try {
+					boolean prunedATStates = HSQLDBDatabasePruning.pruneATStates((HSQLDBRepository) repository);
+					boolean prunedBlocks = HSQLDBDatabasePruning.pruneBlocks((HSQLDBRepository) repository);
+
+					// Perform repository maintenance to shrink the db size down
+					if (prunedATStates && prunedBlocks) {
+						HSQLDBDatabasePruning.performMaintenance(repository);
+						return true;
+					}
+
+				} catch (SQLException | DataException e) {
+					LOGGER.info("Unable to bulk prune AT states. The database may have been left in an inconsistent state.");
+				}
+			}
+			else {
+				LOGGER.info("Unable to prune blocks due to missing ATStatesHeightIndex. Bootstrapping is recommended.");
+			}
+		}
+		return false;
+	}
+
 	public static void setRequestedCheckpoint(Boolean quick) {
 		quickCheckpointRequested = quick;
 	}
@@ -77,4 +133,12 @@ public abstract class RepositoryManager {
 		return SQLException.class.isInstance(cause) && repositoryFactory.isDeadlockException((SQLException) cause);
 	}
 
+	public static boolean canArchiveOrPrune() {
+		try (final Repository repository = getRepository()) {
+			return repository.getATRepository().hasAtStatesHeightIndex();
+		} catch (DataException e) {
+			return false;
+		}
+	}
+
 }

src/main/java/org/qortal/repository/hsqldb/HSQLDBATRepository.java

@@ -8,6 +8,7 @@ import java.util.Set;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.qortal.controller.Controller;
 import org.qortal.data.at.ATData;
 import org.qortal.data.at.ATStateData;
 import org.qortal.repository.ATRepository;
@@ -600,6 +601,44 @@ public class HSQLDBATRepository implements ATRepository {
 		return atStates;
 	}
 
+
+	@Override
+	public void rebuildLatestAtStates() throws DataException {
+		// latestATStatesLock is to prevent concurrent updates on LatestATStates
+		// that could result in one process using a partial or empty dataset
+		// because it was in the process of being rebuilt by another thread
+		synchronized (this.repository.latestATStatesLock) {
+			LOGGER.trace("Rebuilding latest AT states...");
+
+			// Rebuild cache of latest AT states that we can't trim
+			String deleteSql = "DELETE FROM LatestATStates";
+			try {
+				this.repository.executeCheckedUpdate(deleteSql);
+			} catch (SQLException e) {
+				repository.examineException(e);
+				throw new DataException("Unable to delete temporary latest AT states cache from repository", e);
+			}
+
+			String insertSql = "INSERT INTO LatestATStates ("
+					+ "SELECT AT_address, height FROM ATs "
+					+ "CROSS JOIN LATERAL("
+					+ "SELECT height FROM ATStates "
+					+ "WHERE ATStates.AT_address = ATs.AT_address "
+					+ "ORDER BY AT_address DESC, height DESC LIMIT 1"
+					+ ") "
+					+ ")";
+			try {
+				this.repository.executeCheckedUpdate(insertSql);
+			} catch (SQLException e) {
+				repository.examineException(e);
+				throw new DataException("Unable to populate temporary latest AT states cache in repository", e);
+			}
+			this.repository.saveChanges();
+			LOGGER.trace("Rebuilt latest AT states");
+		}
+	}
+
+
 	@Override
 	public int getAtTrimHeight() throws DataException {
 		String sql = "SELECT AT_trim_height FROM DatabaseInfo";
@@ -625,63 +664,153 @@ public class HSQLDBATRepository implements ATRepository {
 				this.repository.executeCheckedUpdate(updateSql, trimHeight);
 				this.repository.saveChanges();
 			} catch (SQLException e) {
-				repository.examineException(e);
+				this.repository.examineException(e);
 				throw new DataException("Unable to set AT state trim height in repository", e);
 			}
 		}
 	}
 
-	@Override
-	public void prepareForAtStateTrimming() throws DataException {
-		// Rebuild cache of latest AT states that we can't trim
-		String deleteSql = "DELETE FROM LatestATStates";
-		try {
-			this.repository.executeCheckedUpdate(deleteSql);
-		} catch (SQLException e) {
-			repository.examineException(e);
-			throw new DataException("Unable to delete temporary latest AT states cache from repository", e);
-		}
-
-		String insertSql = "INSERT INTO LatestATStates ("
-				+ "SELECT AT_address, height FROM ATs "
-				+ "CROSS JOIN LATERAL("
-					+ "SELECT height FROM ATStates "
-					+ "WHERE ATStates.AT_address = ATs.AT_address "
-					+ "ORDER BY AT_address DESC, height DESC LIMIT 1"
-				+ ") "
-			+ ")";
-		try {
-			this.repository.executeCheckedUpdate(insertSql);
-		} catch (SQLException e) {
-			repository.examineException(e);
-			throw new DataException("Unable to populate temporary latest AT states cache in repository", e);
-		}
-	}
-
 	@Override
 	public int trimAtStates(int minHeight, int maxHeight, int limit) throws DataException {
 		if (minHeight >= maxHeight)
 			return 0;
 
-		// We're often called so no need to trim all states in one go.
-		// Limit updates to reduce CPU and memory load.
-		String sql = "DELETE FROM ATStatesData "
-				+ "WHERE height BETWEEN ? AND ? "
-				+ "AND NOT EXISTS("
+		// latestATStatesLock is to prevent concurrent updates on LatestATStates
+		// that could result in one process using a partial or empty dataset
+		// because it was in the process of being rebuilt by another thread
+		synchronized (this.repository.latestATStatesLock) {
+
+			// We're often called so no need to trim all states in one go.
+			// Limit updates to reduce CPU and memory load.
+			String sql = "DELETE FROM ATStatesData "
+					+ "WHERE height BETWEEN ? AND ? "
+					+ "AND NOT EXISTS("
 					+ "SELECT TRUE FROM LatestATStates "
 					+ "WHERE LatestATStates.AT_address = ATStatesData.AT_address "
 					+ "AND LatestATStates.height = ATStatesData.height"
-				+ ") "
-				+ "LIMIT ?";
+					+ ") "
+					+ "LIMIT ?";
 
-		try {
-			return this.repository.executeCheckedUpdate(sql, minHeight, maxHeight, limit);
-		} catch (SQLException e) {
-			repository.examineException(e);
-			throw new DataException("Unable to trim AT states in repository", e);
+			try {
+				int modifiedRows = this.repository.executeCheckedUpdate(sql, minHeight, maxHeight, limit);
+				this.repository.saveChanges();
+				return modifiedRows;
+
+			} catch (SQLException e) {
+				repository.examineException(e);
+				throw new DataException("Unable to trim AT states in repository", e);
+			}
 		}
 	}
 
+
+	@Override
+	public int getAtPruneHeight() throws DataException {
+		String sql = "SELECT AT_prune_height FROM DatabaseInfo";
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql)) {
+			if (resultSet == null)
+				return 0;
+
+			return resultSet.getInt(1);
+		} catch (SQLException e) {
+			throw new DataException("Unable to fetch AT state prune height from repository", e);
+		}
+	}
+
+	@Override
+	public void setAtPruneHeight(int pruneHeight) throws DataException {
+		// trimHeightsLock is to prevent concurrent update on DatabaseInfo
+		// that could result in "transaction rollback: serialization failure"
+		synchronized (this.repository.trimHeightsLock) {
+			String updateSql = "UPDATE DatabaseInfo SET AT_prune_height = ?";
+
+			try {
+				this.repository.executeCheckedUpdate(updateSql, pruneHeight);
+				this.repository.saveChanges();
+			} catch (SQLException e) {
+				repository.examineException(e);
+				throw new DataException("Unable to set AT state prune height in repository", e);
+			}
+		}
+	}
+
+	@Override
+	public int pruneAtStates(int minHeight, int maxHeight) throws DataException {
+		// latestATStatesLock is to prevent concurrent updates on LatestATStates
+		// that could result in one process using a partial or empty dataset
+		// because it was in the process of being rebuilt by another thread
+		synchronized (this.repository.latestATStatesLock) {
+
+			int deletedCount = 0;
+
+			for (int height = minHeight; height <= maxHeight; height++) {
+
+				// Give up if we're stopping
+				if (Controller.isStopping()) {
+					return deletedCount;
+				}
+
+				// Get latest AT states for this height
+				List<String> atAddresses = new ArrayList<>();
+				String updateSql = "SELECT AT_address FROM LatestATStates WHERE height = ?";
+				try (ResultSet resultSet = this.repository.checkedExecute(updateSql, height)) {
+					if (resultSet != null) {
+						do {
+							String atAddress = resultSet.getString(1);
+							atAddresses.add(atAddress);
+
+						} while (resultSet.next());
+					}
+				} catch (SQLException e) {
+					throw new DataException("Unable to fetch latest AT states from repository", e);
+				}
+
+				List<ATStateData> atStates = this.getBlockATStatesAtHeight(height);
+				for (ATStateData atState : atStates) {
+					//LOGGER.info("Found atState {} at height {}", atState.getATAddress(), atState.getHeight());
+
+					// Give up if we're stopping
+					if (Controller.isStopping()) {
+						return deletedCount;
+					}
+
+					if (atAddresses.contains(atState.getATAddress())) {
+						// We don't want to delete this AT state because it is still active
+						LOGGER.trace("Skipping atState {} at height {}", atState.getATAddress(), atState.getHeight());
+						continue;
+					}
+
+					// Safe to delete everything else for this height
+					try {
+						this.repository.delete("ATStates", "AT_address = ? AND height = ?",
+								atState.getATAddress(), atState.getHeight());
+						deletedCount++;
+					} catch (SQLException e) {
+						throw new DataException("Unable to delete AT state data from repository", e);
+					}
+				}
+			}
+			this.repository.saveChanges();
+
+			return deletedCount;
+		}
+	}
+
+
+	@Override
+	public boolean hasAtStatesHeightIndex() throws DataException {
+		String sql = "SELECT INDEX_NAME FROM INFORMATION_SCHEMA.SYSTEM_INDEXINFO where INDEX_NAME='ATSTATESHEIGHTINDEX'";
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql)) {
+			return resultSet != null;
+
+		} catch (SQLException e) {
+			throw new DataException("Unable to check for ATStatesHeightIndex in repository", e);
+		}
+	}
+
+
 	@Override
 	public void save(ATStateData atStateData) throws DataException {
 		// We shouldn't ever save partial ATStateData

src/main/java/org/qortal/repository/hsqldb/HSQLDBAccountRepository.java

@@ -904,6 +904,25 @@ public class HSQLDBAccountRepository implements AccountRepository {
 		}
 	}
 
+	@Override
+	public MintingAccountData getMintingAccount(byte[] mintingAccountKey) throws DataException {
+		try (ResultSet resultSet = this.repository.checkedExecute("SELECT minter_private_key, minter_public_key " +
+				"FROM MintingAccounts WHERE minter_private_key = ? OR minter_public_key = ?",
+				mintingAccountKey, mintingAccountKey)) {
+
+			if (resultSet == null)
+				return null;
+
+				byte[] minterPrivateKey = resultSet.getBytes(1);
+				byte[] minterPublicKey = resultSet.getBytes(2);
+
+				return new MintingAccountData(minterPrivateKey, minterPublicKey);
+
+		} catch (SQLException e) {
+			throw new DataException("Unable to fetch minting accounts from repository", e);
+		}
+	}
+
 	@Override
 	public void save(MintingAccountData mintingAccountData) throws DataException {
 		HSQLDBSaver saveHelper = new HSQLDBSaver("MintingAccounts");

src/main/java/org/qortal/repository/hsqldb/HSQLDBBlockArchiveRepository.java

@@ -0,0 +1,310 @@
+package org.qortal.repository.hsqldb;
+
+import org.qortal.api.ApiError;
+import org.qortal.api.ApiExceptionFactory;
+import org.qortal.api.model.BlockSignerSummary;
+import org.qortal.block.Block;
+import org.qortal.data.block.BlockArchiveData;
+import org.qortal.data.block.BlockData;
+import org.qortal.data.block.BlockSummaryData;
+import org.qortal.repository.BlockArchiveReader;
+import org.qortal.repository.BlockArchiveRepository;
+import org.qortal.repository.DataException;
+import org.qortal.utils.Triple;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class HSQLDBBlockArchiveRepository implements BlockArchiveRepository {
+
+    protected HSQLDBRepository repository;
+
+    public HSQLDBBlockArchiveRepository(HSQLDBRepository repository) {
+        this.repository = repository;
+    }
+
+
+    @Override
+    public BlockData fromSignature(byte[] signature) throws DataException {
+        Triple blockInfo = BlockArchiveReader.getInstance().fetchBlockWithSignature(signature, this.repository);
+        if (blockInfo != null) {
+            return (BlockData) blockInfo.getA();
+        }
+        return null;
+    }
+
+    @Override
+    public int getHeightFromSignature(byte[] signature) throws DataException {
+        Integer height = BlockArchiveReader.getInstance().fetchHeightForSignature(signature, this.repository);
+        if (height == null || height == 0) {
+            return 0;
+        }
+        return height;
+    }
+
+    @Override
+    public BlockData fromHeight(int height) throws DataException {
+        Triple blockInfo = BlockArchiveReader.getInstance().fetchBlockAtHeight(height);
+        if (blockInfo != null) {
+            return (BlockData) blockInfo.getA();
+        }
+        return null;
+    }
+
+    @Override
+    public List<BlockData> fromRange(int startHeight, int endHeight) throws DataException {
+        List<BlockData> blocks = new ArrayList<>();
+
+        for (int height = startHeight; height < endHeight; height++) {
+            BlockData blockData = this.fromHeight(height);
+            if (blockData == null) {
+                return blocks;
+            }
+            blocks.add(blockData);
+        }
+        return blocks;
+    }
+
+    @Override
+    public BlockData fromReference(byte[] reference) throws DataException {
+        BlockData referenceBlock = this.repository.getBlockArchiveRepository().fromSignature(reference);
+        if (referenceBlock == null) {
+            // Try the main block repository. Needed for genesis block.
+            referenceBlock = this.repository.getBlockRepository().fromSignature(reference);
+        }
+        if (referenceBlock != null) {
+            int height = referenceBlock.getHeight();
+            if (height > 0) {
+                // Request the block at height + 1
+                Triple blockInfo = BlockArchiveReader.getInstance().fetchBlockAtHeight(height + 1);
+                if (blockInfo != null) {
+                    return (BlockData) blockInfo.getA();
+                }
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public int getHeightFromTimestamp(long timestamp) throws DataException {
+        String sql = "SELECT height FROM BlockArchive WHERE minted_when <= ? ORDER BY minted_when DESC, height DESC LIMIT 1";
+
+        try (ResultSet resultSet = this.repository.checkedExecute(sql, timestamp)) {
+            if (resultSet == null) {
+                return 0;
+            }
+            return resultSet.getInt(1);
+
+        } catch (SQLException e) {
+            throw new DataException("Error fetching height from BlockArchive repository", e);
+        }
+    }
+
+    @Override
+    public long getTimestampFromHeight(int height) throws DataException {
+        String sql = "SELECT minted_when FROM BlockArchive WHERE height = ?";
+
+        try (ResultSet resultSet = this.repository.checkedExecute(sql, height)) {
+            if (resultSet == null)
+                return 0;
+
+            return resultSet.getLong(1);
+        } catch (SQLException e) {
+            throw new DataException("Error obtaining block timestamp by height from BlockArchive repository", e);
+        }
+    }
+
+    @Override
+    public List<BlockSummaryData> getBlockSummariesBySigner(byte[] signerPublicKey, Integer limit, Integer offset, Boolean reverse) throws DataException {
+        StringBuilder sql = new StringBuilder(512);
+        sql.append("SELECT signature, height, BlockArchive.minter FROM ");
+
+        // List of minter account's public key and reward-share public keys with minter's public key
+        sql.append("(SELECT * FROM (VALUES (CAST(? AS QortalPublicKey))) UNION (SELECT reward_share_public_key FROM RewardShares WHERE minter_public_key = ?)) AS PublicKeys (public_key) ");
+
+        // Match BlockArchive blocks signed with public key from above list
+        sql.append("JOIN BlockArchive ON BlockArchive.minter = public_key ");
+
+        sql.append("ORDER BY BlockArchive.height ");
+        if (reverse != null && reverse)
+            sql.append("DESC ");
+
+        HSQLDBRepository.limitOffsetSql(sql, limit, offset);
+
+        List<BlockSummaryData> blockSummaries = new ArrayList<>();
+
+        try (ResultSet resultSet = this.repository.checkedExecute(sql.toString(), signerPublicKey, signerPublicKey)) {
+            if (resultSet == null)
+                return blockSummaries;
+
+            do {
+                byte[] signature = resultSet.getBytes(1);
+                int height = resultSet.getInt(2);
+                byte[] blockMinterPublicKey = resultSet.getBytes(3);
+
+                // Fetch additional info from the archive itself
+                int onlineAccountsCount = 0;
+                BlockData blockData = this.fromSignature(signature);
+                if (blockData != null) {
+                    onlineAccountsCount = blockData.getOnlineAccountsCount();
+                }
+
+                BlockSummaryData blockSummary = new BlockSummaryData(height, signature, blockMinterPublicKey, onlineAccountsCount);
+                blockSummaries.add(blockSummary);
+            } while (resultSet.next());
+
+            return blockSummaries;
+        } catch (SQLException e) {
+            throw new DataException("Unable to fetch minter's block summaries from repository", e);
+        }
+    }
+
+    @Override
+    public List<BlockSignerSummary> getBlockSigners(List<String> addresses, Integer limit, Integer offset, Boolean reverse) throws DataException {
+        String subquerySql = "SELECT minter, COUNT(signature) FROM (" +
+                    "(SELECT minter, signature FROM Blocks) UNION ALL (SELECT minter, signature FROM BlockArchive)" +
+                ") GROUP BY minter";
+
+        StringBuilder sql = new StringBuilder(1024);
+        sql.append("SELECT DISTINCT block_minter, n_blocks, minter_public_key, minter, recipient FROM (");
+        sql.append(subquerySql);
+        sql.append(") AS Minters (block_minter, n_blocks) LEFT OUTER JOIN RewardShares ON reward_share_public_key = block_minter ");
+
+        if (addresses != null && !addresses.isEmpty()) {
+            sql.append(" LEFT OUTER JOIN Accounts AS BlockMinterAccounts ON BlockMinterAccounts.public_key = block_minter ");
+            sql.append(" LEFT OUTER JOIN Accounts AS RewardShareMinterAccounts ON RewardShareMinterAccounts.public_key = minter_public_key ");
+            sql.append(" JOIN (VALUES ");
+
+            final int addressesSize = addresses.size();
+            for (int ai = 0; ai < addressesSize; ++ai) {
+                if (ai != 0)
+                    sql.append(", ");
+
+                sql.append("(?)");
+            }
+
+            sql.append(") AS FilterAccounts (account) ");
+            sql.append(" ON FilterAccounts.account IN (recipient, BlockMinterAccounts.account, RewardShareMinterAccounts.account) ");
+        } else {
+            addresses = Collections.emptyList();
+        }
+
+        sql.append("ORDER BY n_blocks ");
+        if (reverse != null && reverse)
+            sql.append("DESC ");
+
+        HSQLDBRepository.limitOffsetSql(sql, limit, offset);
+
+        List<BlockSignerSummary> summaries = new ArrayList<>();
+
+        try (ResultSet resultSet = this.repository.checkedExecute(sql.toString(), addresses.toArray())) {
+            if (resultSet == null)
+                return summaries;
+
+            do {
+                byte[] blockMinterPublicKey = resultSet.getBytes(1);
+                int nBlocks = resultSet.getInt(2);
+
+                // May not be present if no reward-share:
+                byte[] mintingAccountPublicKey = resultSet.getBytes(3);
+                String minterAccount = resultSet.getString(4);
+                String recipientAccount = resultSet.getString(5);
+
+                BlockSignerSummary blockSignerSummary;
+                if (recipientAccount == null)
+                    blockSignerSummary = new BlockSignerSummary(blockMinterPublicKey, nBlocks);
+                else
+                    blockSignerSummary = new BlockSignerSummary(blockMinterPublicKey, nBlocks, mintingAccountPublicKey, minterAccount, recipientAccount);
+
+                summaries.add(blockSignerSummary);
+            } while (resultSet.next());
+
+            return summaries;
+        } catch (SQLException e) {
+            throw new DataException("Unable to fetch block minters from repository", e);
+        }
+    }
+
+
+    @Override
+    public int getBlockArchiveHeight() throws DataException {
+        String sql = "SELECT block_archive_height FROM DatabaseInfo";
+
+        try (ResultSet resultSet = this.repository.checkedExecute(sql)) {
+            if (resultSet == null)
+                return 0;
+
+            return resultSet.getInt(1);
+        } catch (SQLException e) {
+            throw new DataException("Unable to fetch block archive height from repository", e);
+        }
+    }
+
+    @Override
+    public void setBlockArchiveHeight(int archiveHeight) throws DataException {
+        // trimHeightsLock is to prevent concurrent update on DatabaseInfo
+        // that could result in "transaction rollback: serialization failure"
+        synchronized (this.repository.trimHeightsLock) {
+            String updateSql = "UPDATE DatabaseInfo SET block_archive_height = ?";
+
+            try {
+                this.repository.executeCheckedUpdate(updateSql, archiveHeight);
+                this.repository.saveChanges();
+            } catch (SQLException e) {
+                repository.examineException(e);
+                throw new DataException("Unable to set block archive height in repository", e);
+            }
+        }
+    }
+
+
+    @Override
+    public BlockArchiveData getBlockArchiveDataForSignature(byte[] signature) throws DataException {
+        String sql = "SELECT height, signature, minted_when, minter FROM BlockArchive WHERE signature = ? LIMIT 1";
+
+        try (ResultSet resultSet = this.repository.checkedExecute(sql, signature)) {
+            if (resultSet == null) {
+                return null;
+            }
+            int height = resultSet.getInt(1);
+            byte[] sig = resultSet.getBytes(2);
+            long timestamp = resultSet.getLong(3);
+            byte[] minterPublicKey = resultSet.getBytes(4);
+            return new BlockArchiveData(sig, height, timestamp, minterPublicKey);
+
+        } catch (SQLException e) {
+            throw new DataException("Error fetching height from BlockArchive repository", e);
+        }
+    }
+
+
+    @Override
+    public void save(BlockArchiveData blockArchiveData) throws DataException {
+        HSQLDBSaver saveHelper = new HSQLDBSaver("BlockArchive");
+
+        saveHelper.bind("signature", blockArchiveData.getSignature())
+                .bind("height", blockArchiveData.getHeight())
+                .bind("minted_when", blockArchiveData.getTimestamp())
+                .bind("minter", blockArchiveData.getMinterPublicKey());
+
+        try {
+            saveHelper.execute(this.repository);
+        } catch (SQLException e) {
+            throw new DataException("Unable to save SimpleBlockData into BlockArchive repository", e);
+        }
+    }
+
+    @Override
+    public void delete(BlockArchiveData blockArchiveData) throws DataException {
+        try {
+            this.repository.delete("BlockArchive",
+                    "block_signature = ?", blockArchiveData.getSignature());
+        } catch (SQLException e) {
+            throw new DataException("Unable to delete SimpleBlockData from BlockArchive repository", e);
+        }
+    }
+
+}

src/main/java/org/qortal/repository/hsqldb/HSQLDBBlockRepository.java

@@ -10,6 +10,7 @@ import org.qortal.api.model.BlockSignerSummary;
 import org.qortal.data.block.BlockData;
 import org.qortal.data.block.BlockSummaryData;
 import org.qortal.data.block.BlockTransactionData;
+import org.qortal.data.block.BlockArchiveData;
 import org.qortal.data.transaction.TransactionData;
 import org.qortal.repository.BlockRepository;
 import org.qortal.repository.DataException;
@@ -382,86 +383,6 @@ public class HSQLDBBlockRepository implements BlockRepository {
 		}
 	}
 
-	@Override
-	public List<BlockSummaryData> getBlockSummaries(Integer startHeight, Integer endHeight, Integer count) throws DataException {
-		StringBuilder sql = new StringBuilder(512);
-		List<Object> bindParams = new ArrayList<>();
-
-		sql.append("SELECT signature, height, minter, online_accounts_count, minted_when, transaction_count ");
-
-		/*
-		 * start	end		count		result
-		 * 10		40		null		blocks 10 to 39 (excludes end block, ignore count)
-		 * 
-		 * null		null	null		blocks 1 to 50 (assume count=50, maybe start=1)
-		 * 30		null	null		blocks 30 to 79 (assume count=50)
-		 * 30		null	10			blocks 30 to 39
-		 * 
-		 * null		null	50			last 50 blocks? so if max(blocks.height) is 200, then blocks 151 to 200
-		 * null		200		null		blocks 150 to 199 (excludes end block, assume count=50)
-		 * null		200		10			blocks 190 to 199 (excludes end block)
-		 */
-
-		if (startHeight != null && endHeight != null) {
-			sql.append("FROM Blocks ");
-			sql.append("WHERE height BETWEEN ? AND ?");
-			bindParams.add(startHeight);
-			bindParams.add(Integer.valueOf(endHeight - 1));
-		} else if (endHeight != null || (startHeight == null && count != null)) {
-			// we are going to return blocks from the end of the chain
-			if (count == null)
-				count = 50;
-
-			if (endHeight == null) {
-				sql.append("FROM (SELECT height FROM Blocks ORDER BY height DESC LIMIT 1) AS MaxHeights (max_height) ");
-				sql.append("JOIN Blocks ON height BETWEEN (max_height - ? + 1) AND max_height ");
-				bindParams.add(count);
-			} else {
-				sql.append("FROM Blocks ");
-				sql.append("WHERE height BETWEEN ? AND ?");
-				bindParams.add(Integer.valueOf(endHeight - count));
-				bindParams.add(Integer.valueOf(endHeight - 1));
-			}
-
-		} else {
-			// we are going to return blocks from the start of the chain
-			if (startHeight == null)
-				startHeight = 1;
-
-			if (count == null)
-				count = 50;
-
-			sql.append("FROM Blocks ");
-			sql.append("WHERE height BETWEEN ? AND ?");
-			bindParams.add(startHeight);
-			bindParams.add(Integer.valueOf(startHeight + count - 1));
-		}
-
-		List<BlockSummaryData> blockSummaries = new ArrayList<>();
-
-		try (ResultSet resultSet = this.repository.checkedExecute(sql.toString(), bindParams.toArray())) {
-			if (resultSet == null)
-				return blockSummaries;
-
-			do {
-				byte[] signature = resultSet.getBytes(1);
-				int height = resultSet.getInt(2);
-				byte[] minterPublicKey = resultSet.getBytes(3);
-				int onlineAccountsCount = resultSet.getInt(4);
-				long timestamp = resultSet.getLong(5);
-				int transactionCount = resultSet.getInt(6);
-
-				BlockSummaryData blockSummary = new BlockSummaryData(height, signature, minterPublicKey, onlineAccountsCount,
-						timestamp, transactionCount);
-				blockSummaries.add(blockSummary);
-			} while (resultSet.next());
-
-			return blockSummaries;
-		} catch (SQLException e) {
-			throw new DataException("Unable to fetch height-ranged block summaries from repository", e);
-		}
-	}
-
 	@Override
 	public int getOnlineAccountsSignaturesTrimHeight() throws DataException {
 		String sql = "SELECT online_signatures_trim_height FROM DatabaseInfo";
@@ -509,6 +430,53 @@ public class HSQLDBBlockRepository implements BlockRepository {
 		}
 	}
 
+
+	@Override
+	public int getBlockPruneHeight() throws DataException {
+		String sql = "SELECT block_prune_height FROM DatabaseInfo";
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql)) {
+			if (resultSet == null)
+				return 0;
+
+			return resultSet.getInt(1);
+		} catch (SQLException e) {
+			throw new DataException("Unable to fetch block prune height from repository", e);
+		}
+	}
+
+	@Override
+	public void setBlockPruneHeight(int pruneHeight) throws DataException {
+		// trimHeightsLock is to prevent concurrent update on DatabaseInfo
+		// that could result in "transaction rollback: serialization failure"
+		synchronized (this.repository.trimHeightsLock) {
+			String updateSql = "UPDATE DatabaseInfo SET block_prune_height = ?";
+
+			try {
+				this.repository.executeCheckedUpdate(updateSql, pruneHeight);
+				this.repository.saveChanges();
+			} catch (SQLException e) {
+				repository.examineException(e);
+				throw new DataException("Unable to set block prune height in repository", e);
+			}
+		}
+	}
+
+	@Override
+	public int pruneBlocks(int minHeight, int maxHeight) throws DataException {
+		// Don't prune the genesis block
+		if (minHeight <= 1) {
+			minHeight = 2;
+		}
+
+		try {
+			return this.repository.delete("Blocks", "height BETWEEN ? AND ?", minHeight, maxHeight);
+		} catch (SQLException e) {
+			throw new DataException("Unable to prune blocks from repository", e);
+		}
+	}
+
+
 	@Override
 	public BlockData getDetachedBlockSignature(int startHeight) throws DataException {
 		String sql = "SELECT " + BLOCK_DB_COLUMNS + " FROM Blocks "

src/main/java/org/qortal/repository/hsqldb/HSQLDBDatabaseArchiving.java

@@ -0,0 +1,88 @@
+package org.qortal.repository.hsqldb;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.controller.Controller;
+import org.qortal.gui.SplashFrame;
+import org.qortal.repository.BlockArchiveWriter;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+import org.qortal.transform.TransformationException;
+
+import java.io.IOException;
+
+/**
+ *
+ * When switching to an archiving node, we need to archive most of the database contents.
+ * This involves copying its data into flat files.
+ * If we do this entirely as a background process, it is very slow and can interfere with syncing.
+ * However, if we take the approach of doing this in bulk, before starting up the rest of the
+ * processes, this makes it much faster and less invasive.
+ *
+ * From that point, the original background archiving process will run, but can be dialled right down
+ * so not to interfere with syncing.
+ *
+ */
+
+
+public class HSQLDBDatabaseArchiving {
+
+    private static final Logger LOGGER = LogManager.getLogger(HSQLDBDatabaseArchiving.class);
+
+
+    public static boolean buildBlockArchive(Repository repository, long fileSizeTarget) throws DataException {
+
+        // Only build the archive if we haven't already got one that is up to date
+        boolean upToDate = BlockArchiveWriter.isArchiverUpToDate(repository);
+        if (upToDate) {
+            // Already archived
+            return false;
+        }
+
+        LOGGER.info("Building block archive - this process could take a while... (approx. 15 mins on high spec)");
+        SplashFrame.getInstance().updateStatus("Building block archive (takes 60+ mins)...");
+
+        final int maximumArchiveHeight = BlockArchiveWriter.getMaxArchiveHeight(repository);
+        int startHeight = 0;
+
+        while (!Controller.isStopping()) {
+            try {
+                BlockArchiveWriter writer = new BlockArchiveWriter(startHeight, maximumArchiveHeight, repository);
+                writer.setFileSizeTarget(fileSizeTarget);
+                BlockArchiveWriter.BlockArchiveWriteResult result = writer.write();
+                switch (result) {
+                    case OK:
+                        // Increment block archive height
+                        startHeight = writer.getLastWrittenHeight() + 1;
+                        repository.getBlockArchiveRepository().setBlockArchiveHeight(startHeight);
+                        repository.saveChanges();
+                        break;
+
+                    case STOPPING:
+                        return false;
+
+                    case NOT_ENOUGH_BLOCKS:
+                        // We've reached the limit of the blocks we can archive
+                        // Return from the whole method
+                        return true;
+
+                    case BLOCK_NOT_FOUND:
+                        // We tried to archive a block that didn't exist. This is a major failure and likely means
+                        // that a bootstrap or re-sync is needed. Return rom the method
+                        LOGGER.info("Error: block not found when building archive. If this error persists, " +
+                                "a bootstrap or re-sync may be needed.");
+                        return false;
+                }
+
+            } catch (IOException | TransformationException | InterruptedException e) {
+                LOGGER.info("Caught exception when creating block cache", e);
+                return false;
+            }
+        }
+
+        // If we got this far then something went wrong (most likely the app is stopping)
+        return false;
+    }
+
+}

src/main/java/org/qortal/repository/hsqldb/HSQLDBDatabasePruning.java

@@ -0,0 +1,332 @@
+package org.qortal.repository.hsqldb;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.controller.Controller;
+import org.qortal.data.block.BlockData;
+import org.qortal.gui.SplashFrame;
+import org.qortal.repository.BlockArchiveWriter;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.settings.Settings;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.concurrent.TimeoutException;
+
+/**
+ *
+ * When switching from a full node to a pruning node, we need to delete most of the database contents.
+ * If we do this entirely as a background process, it is very slow and can interfere with syncing.
+ * However, if we take the approach of transferring only the necessary rows to a new table and then
+ * deleting the original table, this makes the process much faster. It was taking several days to
+ * delete the AT states in the background, but only a couple of minutes to copy them to a new table.
+ *
+ * The trade off is that we have to go through a form of "reshape" when starting the app for the first
+ * time after enabling pruning mode. But given that this is an opt-in mode, I don't think it will be
+ * a problem.
+ *
+ * Once the pruning is complete, it automatically performs a CHECKPOINT DEFRAG in order to
+ * shrink the database file size down to a fraction of what it was before.
+ *
+ * From this point, the original background process will run, but can be dialled right down so not
+ * to interfere with syncing.
+ *
+ */
+
+
+public class HSQLDBDatabasePruning {
+
+    private static final Logger LOGGER = LogManager.getLogger(HSQLDBDatabasePruning.class);
+
+
+    public static boolean pruneATStates(HSQLDBRepository repository) throws SQLException, DataException {
+
+        // Only bulk prune AT states if we have never done so before
+        int pruneHeight = repository.getATRepository().getAtPruneHeight();
+        if (pruneHeight > 0) {
+            // Already pruned AT states
+            return false;
+        }
+
+        if (Settings.getInstance().isArchiveEnabled()) {
+            // Only proceed if we can see that the archiver has already finished
+            // This way, if the archiver failed for any reason, we can prune once it has had
+            // some opportunities to try again
+            boolean upToDate = BlockArchiveWriter.isArchiverUpToDate(repository);
+            if (!upToDate) {
+                return false;
+            }
+        }
+
+        LOGGER.info("Starting bulk prune of AT states - this process could take a while... " +
+                "(approx. 2 mins on high spec, or upwards of 30 mins in some cases)");
+        SplashFrame.getInstance().updateStatus("Pruning database (takes up to 30 mins)...");
+
+        // Create new AT-states table to hold smaller dataset
+        repository.executeCheckedUpdate("DROP TABLE IF EXISTS ATStatesNew");
+        repository.executeCheckedUpdate("CREATE TABLE ATStatesNew ("
+                + "AT_address QortalAddress, height INTEGER NOT NULL, state_hash ATStateHash NOT NULL, "
+                + "fees QortalAmount NOT NULL, is_initial BOOLEAN NOT NULL, sleep_until_message_timestamp BIGINT, "
+                + "PRIMARY KEY (AT_address, height), "
+                + "FOREIGN KEY (AT_address) REFERENCES ATs (AT_address) ON DELETE CASCADE)");
+        repository.executeCheckedUpdate("SET TABLE ATStatesNew NEW SPACE");
+        repository.executeCheckedUpdate("CHECKPOINT");
+
+        // Add a height index
+        LOGGER.info("Adding index to AT states table...");
+        repository.executeCheckedUpdate("CREATE INDEX IF NOT EXISTS ATStatesNewHeightIndex ON ATStatesNew (height)");
+        repository.executeCheckedUpdate("CHECKPOINT");
+
+
+        // Find our latest block
+        BlockData latestBlock = repository.getBlockRepository().getLastBlock();
+        if (latestBlock == null) {
+            LOGGER.info("Unable to determine blockchain height, necessary for bulk block pruning");
+            return false;
+        }
+
+        // Calculate some constants for later use
+        final int blockchainHeight = latestBlock.getHeight();
+        int maximumBlockToTrim = blockchainHeight - Settings.getInstance().getPruneBlockLimit();
+        if (Settings.getInstance().isArchiveEnabled()) {
+            // Archive mode - don't prune anything that hasn't been archived yet
+            maximumBlockToTrim = Math.min(maximumBlockToTrim, repository.getBlockArchiveRepository().getBlockArchiveHeight() - 1);
+        }
+        final int endHeight = blockchainHeight;
+        final int blockStep = 10000;
+
+
+        // It's essential that we rebuild the latest AT states here, as we are using this data in the next query.
+        // Failing to do this will result in important AT states being deleted, rendering the database unusable.
+        repository.getATRepository().rebuildLatestAtStates();
+
+
+        // Loop through all the LatestATStates and copy them to the new table
+        LOGGER.info("Copying AT states...");
+        for (int height = 0; height < endHeight; height += blockStep) {
+            final int batchEndHeight = height + blockStep - 1;
+            //LOGGER.info(String.format("Copying AT states between %d and %d...", height, batchEndHeight));
+
+            String sql = "SELECT height, AT_address FROM LatestATStates WHERE height BETWEEN ? AND ?";
+            try (ResultSet latestAtStatesResultSet = repository.checkedExecute(sql, height, batchEndHeight)) {
+                if (latestAtStatesResultSet != null) {
+                    do {
+                        int latestAtHeight = latestAtStatesResultSet.getInt(1);
+                        String latestAtAddress = latestAtStatesResultSet.getString(2);
+
+                        // Copy this latest ATState to the new table
+                        //LOGGER.info(String.format("Copying AT %s at height %d...", latestAtAddress, latestAtHeight));
+                        try {
+                            String updateSql = "INSERT INTO ATStatesNew ("
+                                    + "SELECT AT_address, height, state_hash, fees, is_initial, sleep_until_message_timestamp "
+                                    + "FROM ATStates "
+                                    + "WHERE height = ? AND AT_address = ?)";
+                            repository.executeCheckedUpdate(updateSql, latestAtHeight, latestAtAddress);
+                        } catch (SQLException e) {
+                            repository.examineException(e);
+                            throw new DataException("Unable to copy ATStates", e);
+                        }
+
+                        // If this batch includes blocks after the maximum block to trim, we will need to copy
+                        // each of its AT states above maximumBlockToTrim as they are considered "recent". We
+                        // need to do this for _all_ AT states in these blocks, regardless of their latest state.
+                        if (batchEndHeight >= maximumBlockToTrim) {
+                            // Now copy this AT's states for each recent block they are present in
+                            for (int i = maximumBlockToTrim; i < endHeight; i++) {
+                                if (latestAtHeight < i) {
+                                    // This AT finished before this block so there is nothing to copy
+                                    continue;
+                                }
+
+                                //LOGGER.info(String.format("Copying recent AT %s at height %d...", latestAtAddress, i));
+                                try {
+                                    // Copy each LatestATState to the new table
+                                    String updateSql = "INSERT IGNORE INTO ATStatesNew ("
+                                            + "SELECT AT_address, height, state_hash, fees, is_initial, sleep_until_message_timestamp "
+                                            + "FROM ATStates "
+                                            + "WHERE height = ? AND AT_address = ?)";
+                                    repository.executeCheckedUpdate(updateSql, i, latestAtAddress);
+                                } catch (SQLException e) {
+                                    repository.examineException(e);
+                                    throw new DataException("Unable to copy ATStates", e);
+                                }
+                            }
+                        }
+                        repository.saveChanges();
+
+                    } while (latestAtStatesResultSet.next());
+                }
+            } catch (SQLException e) {
+                throw new DataException("Unable to copy AT states", e);
+            }
+        }
+
+
+        // Finally, drop the original table and rename
+        LOGGER.info("Deleting old AT states...");
+        repository.executeCheckedUpdate("DROP TABLE ATStates");
+        repository.executeCheckedUpdate("ALTER TABLE ATStatesNew RENAME TO ATStates");
+        repository.executeCheckedUpdate("ALTER INDEX ATStatesNewHeightIndex RENAME TO ATStatesHeightIndex");
+        repository.executeCheckedUpdate("CHECKPOINT");
+
+        // Update the prune height
+        int nextPruneHeight = maximumBlockToTrim + 1;
+        repository.getATRepository().setAtPruneHeight(nextPruneHeight);
+        repository.saveChanges();
+
+        repository.executeCheckedUpdate("CHECKPOINT");
+
+        // Now prune/trim the ATStatesData, as this currently goes back over a month
+        return HSQLDBDatabasePruning.pruneATStateData(repository);
+    }
+
+    /*
+     * Bulk prune ATStatesData to catch up with the now pruned ATStates table
+     * This uses the existing AT States trimming code but with a much higher end block
+     */
+    private static boolean pruneATStateData(Repository repository) throws DataException {
+
+        if (Settings.getInstance().isArchiveEnabled()) {
+            // Don't prune ATStatesData in archive mode
+            return true;
+        }
+
+        BlockData latestBlock = repository.getBlockRepository().getLastBlock();
+        if (latestBlock == null) {
+            LOGGER.info("Unable to determine blockchain height, necessary for bulk ATStatesData pruning");
+            return false;
+        }
+        final int blockchainHeight = latestBlock.getHeight();
+        int upperPrunableHeight = blockchainHeight - Settings.getInstance().getPruneBlockLimit();
+        // ATStateData is already trimmed - so carry on from where we left off in the past
+        int pruneStartHeight = repository.getATRepository().getAtTrimHeight();
+
+        LOGGER.info("Starting bulk prune of AT states data - this process could take a while... (approx. 3 mins on high spec)");
+
+        while (pruneStartHeight < upperPrunableHeight) {
+            // Prune all AT state data up until our latest minus pruneBlockLimit (or our archive height)
+
+            if (Controller.isStopping()) {
+                return false;
+            }
+
+            // Override batch size in the settings because this is a one-off process
+            final int batchSize = 1000;
+            final int rowLimitPerBatch = 50000;
+            int upperBatchHeight = pruneStartHeight + batchSize;
+            int upperPruneHeight = Math.min(upperBatchHeight, upperPrunableHeight);
+
+            LOGGER.trace(String.format("Pruning AT states data between %d and %d...", pruneStartHeight, upperPruneHeight));
+
+            int numATStatesPruned = repository.getATRepository().trimAtStates(pruneStartHeight, upperPruneHeight, rowLimitPerBatch);
+            repository.saveChanges();
+
+            if (numATStatesPruned > 0) {
+                LOGGER.trace(String.format("Pruned %d AT states data rows between blocks %d and %d",
+                        numATStatesPruned, pruneStartHeight, upperPruneHeight));
+            } else {
+                repository.getATRepository().setAtTrimHeight(upperBatchHeight);
+                // No need to rebuild the latest AT states as we aren't currently synchronizing
+                repository.saveChanges();
+                LOGGER.debug(String.format("Bumping AT states trim height to %d", upperBatchHeight));
+
+                // Can we move onto next batch?
+                if (upperPrunableHeight > upperBatchHeight) {
+                    pruneStartHeight = upperBatchHeight;
+                }
+                else {
+                    // We've finished pruning
+                    break;
+                }
+            }
+        }
+
+        return true;
+    }
+
+    public static boolean pruneBlocks(Repository repository) throws SQLException, DataException {
+
+        // Only bulk prune AT states if we have never done so before
+        int pruneHeight = repository.getBlockRepository().getBlockPruneHeight();
+        if (pruneHeight > 0) {
+            // Already pruned blocks
+            return false;
+        }
+
+        if (Settings.getInstance().isArchiveEnabled()) {
+            // Only proceed if we can see that the archiver has already finished
+            // This way, if the archiver failed for any reason, we can prune once it has had
+            // some opportunities to try again
+            boolean upToDate = BlockArchiveWriter.isArchiverUpToDate(repository);
+            if (!upToDate) {
+                return false;
+            }
+        }
+
+        BlockData latestBlock = repository.getBlockRepository().getLastBlock();
+        if (latestBlock == null) {
+            LOGGER.info("Unable to determine blockchain height, necessary for bulk block pruning");
+            return false;
+        }
+        final int blockchainHeight = latestBlock.getHeight();
+        int upperPrunableHeight = blockchainHeight - Settings.getInstance().getPruneBlockLimit();
+        int pruneStartHeight = 0;
+
+        if (Settings.getInstance().isArchiveEnabled()) {
+            // Archive mode - don't prune anything that hasn't been archived yet
+            upperPrunableHeight = Math.min(upperPrunableHeight, repository.getBlockArchiveRepository().getBlockArchiveHeight() - 1);
+        }
+
+        LOGGER.info("Starting bulk prune of blocks - this process could take a while... (approx. 5 mins on high spec)");
+
+        while (pruneStartHeight < upperPrunableHeight) {
+            // Prune all blocks up until our latest minus pruneBlockLimit
+
+            int upperBatchHeight = pruneStartHeight + Settings.getInstance().getBlockPruneBatchSize();
+            int upperPruneHeight = Math.min(upperBatchHeight, upperPrunableHeight);
+
+            LOGGER.info(String.format("Pruning blocks between %d and %d...", pruneStartHeight, upperPruneHeight));
+
+            int numBlocksPruned = repository.getBlockRepository().pruneBlocks(pruneStartHeight, upperPruneHeight);
+            repository.saveChanges();
+
+            if (numBlocksPruned > 0) {
+                LOGGER.info(String.format("Pruned %d block%s between %d and %d",
+                        numBlocksPruned, (numBlocksPruned != 1 ? "s" : ""),
+                        pruneStartHeight, upperPruneHeight));
+            } else {
+                final int nextPruneHeight = upperPruneHeight + 1;
+                repository.getBlockRepository().setBlockPruneHeight(nextPruneHeight);
+                repository.saveChanges();
+                LOGGER.debug(String.format("Bumping block base prune height to %d", nextPruneHeight));
+
+                // Can we move onto next batch?
+                if (upperPrunableHeight > nextPruneHeight) {
+                    pruneStartHeight = nextPruneHeight;
+                }
+                else {
+                    // We've finished pruning
+                    break;
+                }
+            }
+        }
+
+        return true;
+    }
+
+    public static void performMaintenance(Repository repository) throws SQLException, DataException {
+        try {
+            SplashFrame.getInstance().updateStatus("Performing maintenance...");
+
+            // Timeout if the database isn't ready for backing up after 5 minutes
+            // Nothing else should be using the db at this point, so a timeout shouldn't happen
+            long timeout = 5 * 60 * 1000L;
+            repository.performPeriodicMaintenance(timeout);
+
+        } catch (TimeoutException e) {
+            LOGGER.info("Attempt to perform maintenance failed due to timeout: {}", e.getMessage());
+        }
+    }
+
+}

src/main/java/org/qortal/repository/hsqldb/HSQLDBDatabaseUpdates.java

@@ -9,7 +9,9 @@ import java.util.stream.Collectors;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.qortal.controller.Controller;
 import org.qortal.controller.tradebot.BitcoinACCTv1TradeBot;
+import org.qortal.gui.SplashFrame;
 
 public class HSQLDBDatabaseUpdates {
 
@@ -27,9 +29,14 @@ public class HSQLDBDatabaseUpdates {
 	public static boolean updateDatabase(Connection connection) throws SQLException {
 		final boolean wasPristine = fetchDatabaseVersion(connection) == 0;
 
+		SplashFrame.getInstance().updateStatus("Upgrading database, please wait...");
+
 		while (databaseUpdating(connection, wasPristine))
 			incrementDatabaseVersion(connection);
 
+		String text = String.format("Starting Qortal Core v%s...", Controller.getInstance().getVersionStringWithoutPrefix());
+		SplashFrame.getInstance().updateStatus(text);
+
 		return wasPristine;
 	}
 
@@ -837,6 +844,11 @@ public class HSQLDBDatabaseUpdates {
 					stmt.execute("SET TABLE ATStatesNew NEW SPACE");
 					stmt.execute("CHECKPOINT");
 
+					// Add the height index
+					LOGGER.info("Adding index to AT states table...");
+					stmt.execute("CREATE INDEX ATStatesNewHeightIndex ON ATStatesNew (height)");
+					stmt.execute("CHECKPOINT");
+
 					ResultSet resultSet = stmt.executeQuery("SELECT height FROM Blocks ORDER BY height DESC LIMIT 1");
 					final int blockchainHeight = resultSet.next() ? resultSet.getInt(1) : 0;
 					final int heightStep = 100;
@@ -849,14 +861,43 @@ public class HSQLDBDatabaseUpdates {
 								+ "WHERE height BETWEEN " + minHeight + " AND " + (minHeight + heightStep - 1)
 								+ ")");
 						stmt.execute("COMMIT");
+
+						int processed = Math.min(minHeight + heightStep - 1, blockchainHeight);
+						double percentage = (double)processed / (double)blockchainHeight * 100.0f;
+						LOGGER.info(String.format("Processed %d of %d blocks (%.1f%%)", processed, blockchainHeight, percentage));
 					}
 					stmt.execute("CHECKPOINT");
 
 					stmt.execute("DROP TABLE ATStates");
 					stmt.execute("ALTER TABLE ATStatesNew RENAME TO ATStates");
+					stmt.execute("ALTER INDEX ATStatesNewHeightIndex RENAME TO ATStatesHeightIndex");
 					stmt.execute("CHECKPOINT");
 					break;
 				}
+				case 35:
+					// Support for pruning
+					stmt.execute("ALTER TABLE DatabaseInfo ADD AT_prune_height INT NOT NULL DEFAULT 0");
+					stmt.execute("ALTER TABLE DatabaseInfo ADD block_prune_height INT NOT NULL DEFAULT 0");
+					break;
+
+				case 36:
+					// Block archive support
+					stmt.execute("ALTER TABLE DatabaseInfo ADD block_archive_height INT NOT NULL DEFAULT 0");
+
+					// Block archive (lookup table to map signature to height)
+					// Actual data is stored in archive files outside of the database
+					stmt.execute("CREATE TABLE BlockArchive (signature BlockSignature, height INTEGER NOT NULL, "
+							+ "minted_when EpochMillis NOT NULL, minter QortalPublicKey NOT NULL, "
+							+ "PRIMARY KEY (signature))");
+					// For finding blocks by height.
+					stmt.execute("CREATE INDEX BlockArchiveHeightIndex ON BlockArchive (height)");
+					// For finding blocks by the account that minted them.
+					stmt.execute("CREATE INDEX BlockArchiveMinterIndex ON BlockArchive (minter)");
+					// For finding blocks by timestamp or finding height of latest block immediately before timestamp, etc.
+					stmt.execute("CREATE INDEX BlockArchiveTimestampHeightIndex ON BlockArchive (minted_when, height)");
+					// Use a separate table space as this table will be very large.
+					stmt.execute("SET TABLE BlockArchive NEW SPACE");
+					break;
 
 				default:
 					// nothing to do

src/main/java/org/qortal/repository/hsqldb/HSQLDBImportExport.java

@@ -0,0 +1,315 @@
+package org.qortal.repository.hsqldb;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+import org.qortal.data.account.MintingAccountData;
+import org.qortal.data.crosschain.TradeBotData;
+import org.qortal.repository.Bootstrap;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.settings.Settings;
+import org.qortal.utils.Base58;
+import org.qortal.utils.Triple;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Iterator;
+import java.util.List;
+
+public class HSQLDBImportExport {
+
+    private static final Logger LOGGER = LogManager.getLogger(Bootstrap.class);
+
+    public static void backupTradeBotStates(Repository repository, List<TradeBotData> additional) throws DataException {
+        HSQLDBImportExport.backupCurrentTradeBotStates(repository, additional);
+        HSQLDBImportExport.backupArchivedTradeBotStates(repository, additional);
+
+        LOGGER.info("Exported sensitive/node-local data: trade bot states");
+    }
+
+    public static void backupMintingAccounts(Repository repository) throws DataException {
+        HSQLDBImportExport.backupCurrentMintingAccounts(repository);
+
+        LOGGER.info("Exported sensitive/node-local data: minting accounts");
+    }
+
+
+    /* Trade bot states */
+
+    /**
+     * Backs up the trade bot states currently in the repository, without combining them with past ones
+     * @param repository
+     * @param additional - any optional extra trade bot states to include in the backup
+     * @throws DataException
+     */
+    private static void backupCurrentTradeBotStates(Repository repository, List<TradeBotData> additional) throws DataException {
+        try {
+            Path backupDirectory = HSQLDBImportExport.getExportDirectory(true);
+
+            // Load current trade bot data
+            List<TradeBotData> allTradeBotData = repository.getCrossChainRepository().getAllTradeBotData();
+
+
+            // Add any additional entries if specified
+            if (additional != null && !additional.isEmpty()) {
+                allTradeBotData.addAll(additional);
+            }
+
+            // Convert them to JSON objects
+            JSONArray currentTradeBotDataJson = new JSONArray();
+            for (TradeBotData tradeBotData : allTradeBotData) {
+                JSONObject tradeBotDataJson = tradeBotData.toJson();
+                currentTradeBotDataJson.put(tradeBotDataJson);
+            }
+
+            // Wrap current trade bot data in an object to indicate the type
+            JSONObject currentTradeBotDataJsonWrapper = new JSONObject();
+            currentTradeBotDataJsonWrapper.put("type", "tradeBotStates");
+            currentTradeBotDataJsonWrapper.put("dataset", "current");
+            currentTradeBotDataJsonWrapper.put("data", currentTradeBotDataJson);
+
+            // Write current trade bot data (just the ones currently in the database)
+            String fileName = Paths.get(backupDirectory.toString(), "TradeBotStates.json").toString();
+            FileWriter writer = new FileWriter(fileName);
+            writer.write(currentTradeBotDataJsonWrapper.toString(2));
+            writer.close();
+
+        } catch (DataException | IOException e) {
+            throw new DataException("Unable to export trade bot states from repository");
+        }
+    }
+
+    /**
+     * Backs up the trade bot states currently in the repository to a separate "archive" file,
+     * making sure to combine them with any unique states already present in the archive.
+     * @param repository
+     * @param additional - any optional extra trade bot states to include in the backup
+     * @throws DataException
+     */
+    private static void backupArchivedTradeBotStates(Repository repository, List<TradeBotData> additional) throws DataException {
+        try {
+            Path backupDirectory = HSQLDBImportExport.getExportDirectory(true);
+
+            // Load current trade bot data
+            List<TradeBotData> allTradeBotData = repository.getCrossChainRepository().getAllTradeBotData();
+
+            // Add any additional entries if specified
+            if (additional != null && !additional.isEmpty()) {
+                allTradeBotData.addAll(additional);
+            }
+
+            // Convert them to JSON objects
+            JSONArray allTradeBotDataJson = new JSONArray();
+            for (TradeBotData tradeBotData : allTradeBotData) {
+                JSONObject tradeBotDataJson = tradeBotData.toJson();
+                allTradeBotDataJson.put(tradeBotDataJson);
+            }
+
+            // We need to combine existing archived TradeBotStates data before overwriting
+            String fileName = Paths.get(backupDirectory.toString(), "TradeBotStatesArchive.json").toString();
+            File tradeBotStatesBackupFile = new File(fileName);
+            if (tradeBotStatesBackupFile.exists()) {
+
+                String jsonString = new String(Files.readAllBytes(Paths.get(fileName)));
+                Triple<String, String, JSONArray> parsedJSON = HSQLDBImportExport.parseJSONString(jsonString);
+                if (parsedJSON.getA() == null || parsedJSON.getC() == null) {
+                    throw new DataException("Missing data when exporting archived trade bot states");
+                }
+                String type = parsedJSON.getA();
+                String dataset = parsedJSON.getB();
+                JSONArray data = parsedJSON.getC();
+
+                if (!type.equals("tradeBotStates") || !dataset.equals("archive")) {
+                    throw new DataException("Format mismatch when exporting archived trade bot states");
+                }
+
+                Iterator<Object> iterator = data.iterator();
+                while(iterator.hasNext()) {
+                    JSONObject existingTradeBotDataItem = (JSONObject)iterator.next();
+                    String existingTradePrivateKey = (String) existingTradeBotDataItem.get("tradePrivateKey");
+                    // Check if we already have an entry for this trade
+                    boolean found = allTradeBotData.stream().anyMatch(tradeBotData -> Base58.encode(tradeBotData.getTradePrivateKey()).equals(existingTradePrivateKey));
+                    if (found == false)
+                        // Add the data from the backup file to our "allTradeBotDataJson" array as it's not currently in the db
+                        allTradeBotDataJson.put(existingTradeBotDataItem);
+                }
+            }
+
+            // Wrap all trade bot data in an object to indicate the type
+            JSONObject allTradeBotDataJsonWrapper = new JSONObject();
+            allTradeBotDataJsonWrapper.put("type", "tradeBotStates");
+            allTradeBotDataJsonWrapper.put("dataset", "archive");
+            allTradeBotDataJsonWrapper.put("data", allTradeBotDataJson);
+
+            // Write ALL trade bot data to archive (current plus states that are no longer in the database)
+            FileWriter  writer = new FileWriter(fileName);
+            writer.write(allTradeBotDataJsonWrapper.toString(2));
+            writer.close();
+
+        } catch (DataException | IOException e) {
+            throw new DataException("Unable to export trade bot states from repository");
+        }
+    }
+
+
+    /* Minting accounts */
+
+    /**
+     * Backs up the minting accounts currently in the repository, without combining them with past ones
+     * @param repository
+     * @throws DataException
+     */
+    private static void backupCurrentMintingAccounts(Repository repository) throws DataException {
+        try {
+            Path backupDirectory = HSQLDBImportExport.getExportDirectory(true);
+
+            // Load current trade bot data
+            List<MintingAccountData> allMintingAccountData = repository.getAccountRepository().getMintingAccounts();
+            JSONArray currentMintingAccountJson = new JSONArray();
+            for (MintingAccountData mintingAccountData : allMintingAccountData) {
+                JSONObject mintingAccountDataJson = mintingAccountData.toJson();
+                currentMintingAccountJson.put(mintingAccountDataJson);
+            }
+
+            // Wrap current trade bot data in an object to indicate the type
+            JSONObject currentMintingAccountDataJsonWrapper = new JSONObject();
+            currentMintingAccountDataJsonWrapper.put("type", "mintingAccounts");
+            currentMintingAccountDataJsonWrapper.put("dataset", "current");
+            currentMintingAccountDataJsonWrapper.put("data", currentMintingAccountJson);
+
+            // Write current trade bot data (just the ones currently in the database)
+            String fileName = Paths.get(backupDirectory.toString(), "MintingAccounts.json").toString();
+            FileWriter writer = new FileWriter(fileName);
+            writer.write(currentMintingAccountDataJsonWrapper.toString(2));
+            writer.close();
+
+        } catch (DataException | IOException e) {
+            throw new DataException("Unable to export minting accounts from repository");
+        }
+    }
+
+
+    /* Utils */
+
+    /**
+     * Imports data from supplied file
+     * Data type is loaded from the file itself, and if missing, TradeBotStates is assumed
+     *
+     * @param filename
+     * @param repository
+     * @throws DataException
+     * @throws IOException
+     */
+    public static void importDataFromFile(String filename, Repository repository) throws DataException, IOException {
+        Path path = Paths.get(filename);
+        if (!path.toFile().exists()) {
+            throw new FileNotFoundException(String.format("File doesn't exist: %s", filename));
+        }
+        byte[] fileContents = Files.readAllBytes(path);
+        if (fileContents == null) {
+            throw new FileNotFoundException(String.format("Unable to read file contents: %s", filename));
+        }
+
+        LOGGER.info(String.format("Importing %s into repository ...", filename));
+
+        String jsonString = new String(fileContents);
+        Triple<String, String, JSONArray> parsedJSON = HSQLDBImportExport.parseJSONString(jsonString);
+        if (parsedJSON.getA() == null || parsedJSON.getC() == null) {
+            throw new DataException(String.format("Missing data when importing %s into repository", filename));
+        }
+        String type = parsedJSON.getA();
+        JSONArray data = parsedJSON.getC();
+
+        Iterator<Object> iterator = data.iterator();
+        while(iterator.hasNext()) {
+            JSONObject dataJsonObject = (JSONObject)iterator.next();
+
+            if (type.equals("tradeBotStates")) {
+                HSQLDBImportExport.importTradeBotDataJSON(dataJsonObject, repository);
+            }
+            else if (type.equals("mintingAccounts")) {
+                HSQLDBImportExport.importMintingAccountDataJSON(dataJsonObject, repository);
+            }
+            else {
+                throw new DataException(String.format("Unrecognized data type when importing %s into repository", filename));
+            }
+
+        }
+        LOGGER.info(String.format("Imported %s into repository from %s", type, filename));
+    }
+
+    private static void importTradeBotDataJSON(JSONObject tradeBotDataJson, Repository repository) throws DataException {
+        TradeBotData tradeBotData = TradeBotData.fromJson(tradeBotDataJson);
+        repository.getCrossChainRepository().save(tradeBotData);
+    }
+
+    private static void importMintingAccountDataJSON(JSONObject mintingAccountDataJson, Repository repository) throws DataException {
+        MintingAccountData mintingAccountData = MintingAccountData.fromJson(mintingAccountDataJson);
+        repository.getAccountRepository().save(mintingAccountData);
+    }
+
+    public static Path getExportDirectory(boolean createIfNotExists) throws DataException {
+        Path backupPath = Paths.get(Settings.getInstance().getExportPath());
+
+        if (createIfNotExists) {
+            // Create the qortal-backup folder if it doesn't exist
+            try {
+                Files.createDirectories(backupPath);
+            } catch (IOException e) {
+                LOGGER.info(String.format("Unable to create %s folder", backupPath.toString()));
+                throw new DataException(String.format("Unable to create %s folder", backupPath.toString()));
+            }
+        }
+
+        return backupPath;
+    }
+
+    /**
+     * Parses a JSON string and returns "data", "type", and "dataset" fields.
+     * In the case of legacy JSON files with no type, they are assumed to be TradeBotStates archives,
+     * as we had never implemented this for any other types.
+     *
+     * @param jsonString
+     * @return Triple<String, String, JSONArray> (type, dataset, data)
+     */
+    public static Triple<String, String, JSONArray> parseJSONString(String jsonString) throws DataException {
+        String type = null;
+        String dataset = null;
+        JSONArray data = null;
+
+        try {
+            // Firstly try importing the new format
+            JSONObject jsonData = new JSONObject(jsonString);
+            if (jsonData != null && jsonData.getString("type") != null) {
+
+                type = jsonData.getString("type");
+                dataset = jsonData.getString("dataset");
+                data = jsonData.getJSONArray("data");
+            }
+
+        } catch (JSONException e) {
+            // Could be a legacy format which didn't contain a type or any other outer keys, so try importing that
+            // Treat these as TradeBotStates archives, given that this was the only type previously implemented
+            try {
+                type = "tradeBotStates";
+                dataset = "archive";
+                data = new JSONArray(jsonString);
+
+            } catch (JSONException e2) {
+                // Still failed, so give up
+                throw new DataException("Couldn't import JSON file");
+            }
+        }
+
+        return new Triple(type, dataset, data);
+    }
+
+}

src/main/java/org/qortal/repository/hsqldb/HSQLDBRepository.java

@@ -2,7 +2,6 @@ package org.qortal.repository.hsqldb;
 
 import java.awt.TrayIcon.MessageType;
 import java.io.File;
-import java.io.FileWriter;
 import java.io.IOException;
 import java.math.BigDecimal;
 import java.nio.file.Files;
@@ -17,39 +16,20 @@ import java.sql.SQLException;
 import java.sql.Savepoint;
 import java.sql.Statement;
 import java.util.*;
+import java.util.concurrent.TimeoutException;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.stream.Stream;
 
-import org.json.JSONArray;
-import org.json.JSONObject;
-
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.qortal.account.PrivateKeyAccount;
 import org.qortal.crypto.Crypto;
-import org.qortal.data.crosschain.TradeBotData;
 import org.qortal.globalization.Translator;
 import org.qortal.gui.SysTray;
-import org.qortal.repository.ATRepository;
-import org.qortal.repository.AccountRepository;
-import org.qortal.repository.ArbitraryRepository;
-import org.qortal.repository.AssetRepository;
-import org.qortal.repository.BlockRepository;
-import org.qortal.repository.ChatRepository;
-import org.qortal.repository.CrossChainRepository;
-import org.qortal.repository.DataException;
-import org.qortal.repository.GroupRepository;
-import org.qortal.repository.MessageRepository;
-import org.qortal.repository.NameRepository;
-import org.qortal.repository.NetworkRepository;
-import org.qortal.repository.Repository;
-import org.qortal.repository.RepositoryManager;
-import org.qortal.repository.TransactionRepository;
-import org.qortal.repository.VotingRepository;
+import org.qortal.repository.*;
 import org.qortal.repository.hsqldb.transaction.HSQLDBTransactionRepository;
 import org.qortal.settings.Settings;
-import org.qortal.utils.Base58;
 
 public class HSQLDBRepository implements Repository {
 
@@ -69,12 +49,14 @@ public class HSQLDBRepository implements Repository {
 	protected final Map<String, PreparedStatement> preparedStatementCache = new HashMap<>();
 	// We want the same object corresponding to the actual DB
 	protected final Object trimHeightsLock = RepositoryManager.getRepositoryFactory();
+	protected final Object latestATStatesLock = RepositoryManager.getRepositoryFactory();
 
 	private final ATRepository atRepository = new HSQLDBATRepository(this);
 	private final AccountRepository accountRepository = new HSQLDBAccountRepository(this);
 	private final ArbitraryRepository arbitraryRepository = new HSQLDBArbitraryRepository(this);
 	private final AssetRepository assetRepository = new HSQLDBAssetRepository(this);
 	private final BlockRepository blockRepository = new HSQLDBBlockRepository(this);
+	private final BlockArchiveRepository blockArchiveRepository = new HSQLDBBlockArchiveRepository(this);
 	private final ChatRepository chatRepository = new HSQLDBChatRepository(this);
 	private final CrossChainRepository crossChainRepository = new HSQLDBCrossChainRepository(this);
 	private final GroupRepository groupRepository = new HSQLDBGroupRepository(this);
@@ -142,6 +124,11 @@ public class HSQLDBRepository implements Repository {
 		return this.blockRepository;
 	}
 
+	@Override
+	public BlockArchiveRepository getBlockArchiveRepository() {
+		return this.blockArchiveRepository;
+	}
+
 	@Override
 	public ChatRepository getChatRepository() {
 		return this.chatRepository;
@@ -281,7 +268,7 @@ public class HSQLDBRepository implements Repository {
 	public void close() throws DataException {
 		// Already closed? No need to do anything but maybe report double-call
 		if (this.connection == null) {
-			LOGGER.warn("HSQLDBRepository.close() called when repository already closed", new Exception("Repository already closed"));
+			LOGGER.warn("HSQLDBRepository.close() called when repository already closed. This is expected when bootstrapping.");
 			return;
 		}
 
@@ -393,133 +380,104 @@ public class HSQLDBRepository implements Repository {
 	}
 
 	@Override
-	public void backup(boolean quick) throws DataException {
-		if (!quick)
-			// First perform a CHECKPOINT
+	public void backup(boolean quick, String name, Long timeout) throws DataException, TimeoutException {
+		synchronized (CHECKPOINT_LOCK) {
+
+			// We can only perform a CHECKPOINT if no other HSQLDB session is mid-transaction,
+			// otherwise the CHECKPOINT blocks for COMMITs and other threads can't open HSQLDB sessions
+			// due to HSQLDB blocking until CHECKPOINT finishes - i.e. deadlock.
+			// Since we don't want to give up too easily, it's best to wait until the other transaction
+			// count reaches zero, and then continue.
+			this.blockUntilNoOtherTransactions(timeout);
+
+			if (!quick)
+				// First perform a CHECKPOINT
+				try (Statement stmt = this.connection.createStatement()) {
+					LOGGER.info("Performing maintenance - this will take a while...");
+					stmt.execute("CHECKPOINT");
+					stmt.execute("CHECKPOINT DEFRAG");
+					LOGGER.info("Maintenance completed");
+				} catch (SQLException e) {
+					throw new DataException("Unable to prepare repository for backup");
+				}
+
+			// Clean out any previous backup
+			try {
+				String connectionUrl = this.connection.getMetaData().getURL();
+				String dbPathname = getDbPathname(connectionUrl);
+				if (dbPathname == null)
+					throw new DataException("Unable to locate repository for backup?");
+
+				// Doesn't really make sense to backup an in-memory database...
+				if (dbPathname.equals("mem")) {
+					LOGGER.debug("Ignoring request to backup in-memory repository!");
+					return;
+				}
+
+				String backupUrl = buildBackupUrl(dbPathname, name);
+				String backupPathname = getDbPathname(backupUrl);
+				if (backupPathname == null)
+					throw new DataException("Unable to determine location for repository backup?");
+
+				Path backupDirPath = Paths.get(backupPathname).getParent();
+				String backupDirPathname = backupDirPath.toString();
+
+				try (Stream<Path> paths = Files.walk(backupDirPath)) {
+					paths.sorted(Comparator.reverseOrder())
+							.map(Path::toFile)
+							.filter(file -> file.getPath().startsWith(backupDirPathname))
+							.forEach(File::delete);
+				}
+			} catch (NoSuchFileException e) {
+				// Nothing to remove
+			} catch (SQLException | IOException e) {
+				throw new DataException("Unable to remove previous repository backup");
+			}
+
+			// Actually create backup
 			try (Statement stmt = this.connection.createStatement()) {
-				stmt.execute("CHECKPOINT DEFRAG");
+				LOGGER.info("Backing up repository...");
+				stmt.execute(String.format("BACKUP DATABASE TO '%s/' BLOCKING AS FILES", name));
+				LOGGER.info("Backup completed");
 			} catch (SQLException e) {
-				throw new DataException("Unable to prepare repository for backup");
+				throw new DataException("Unable to backup repository");
 			}
 
-		// Clean out any previous backup
-		try {
-			String connectionUrl = this.connection.getMetaData().getURL();
-			String dbPathname = getDbPathname(connectionUrl);
-			if (dbPathname == null)
-				throw new DataException("Unable to locate repository for backup?");
-
-			// Doesn't really make sense to backup an in-memory database...
-			if (dbPathname.equals("mem")) {
-				LOGGER.debug("Ignoring request to backup in-memory repository!");
-				return;
-			}
-
-			String backupUrl = buildBackupUrl(dbPathname);
-			String backupPathname = getDbPathname(backupUrl);
-			if (backupPathname == null)
-				throw new DataException("Unable to determine location for repository backup?");
-
-			Path backupDirPath = Paths.get(backupPathname).getParent();
-			String backupDirPathname = backupDirPath.toString();
-
-			try (Stream<Path> paths = Files.walk(backupDirPath)) {
-				paths.sorted(Comparator.reverseOrder())
-					.map(Path::toFile)
-					.filter(file -> file.getPath().startsWith(backupDirPathname))
-					.forEach(File::delete);
-			}
-		} catch (NoSuchFileException e) {
-			// Nothing to remove
-		} catch (SQLException | IOException e) {
-			throw new DataException("Unable to remove previous repository backup");
-		}
-
-		// Actually create backup
-		try (Statement stmt = this.connection.createStatement()) {
-			stmt.execute("BACKUP DATABASE TO 'backup/' BLOCKING AS FILES");
-		} catch (SQLException e) {
-			throw new DataException("Unable to backup repository");
 		}
 	}
 
 	@Override
-	public void performPeriodicMaintenance() throws DataException {
-		// Defrag DB - takes a while!
-		try (Statement stmt = this.connection.createStatement()) {
-			LOGGER.info("performing maintenance - this will take a while");
-			stmt.execute("CHECKPOINT");
-			stmt.execute("CHECKPOINT DEFRAG");
-			LOGGER.info("maintenance completed");
-		} catch (SQLException e) {
-			throw new DataException("Unable to defrag repository");
+	public void performPeriodicMaintenance(Long timeout) throws DataException, TimeoutException {
+		synchronized (CHECKPOINT_LOCK) {
+
+			// We can only perform a CHECKPOINT if no other HSQLDB session is mid-transaction,
+			// otherwise the CHECKPOINT blocks for COMMITs and other threads can't open HSQLDB sessions
+			// due to HSQLDB blocking until CHECKPOINT finishes - i.e. deadlock.
+			// Since we don't want to give up too easily, it's best to wait until the other transaction
+			// count reaches zero, and then continue.
+			this.blockUntilNoOtherTransactions(timeout);
+
+			// Defrag DB - takes a while!
+			try (Statement stmt = this.connection.createStatement()) {
+				LOGGER.info("performing maintenance - this will take a while");
+				stmt.execute("CHECKPOINT");
+				stmt.execute("CHECKPOINT DEFRAG");
+				LOGGER.info("maintenance completed");
+			} catch (SQLException e) {
+				throw new DataException("Unable to defrag repository");
+			}
 		}
 	}
 
 	@Override
 	public void exportNodeLocalData() throws DataException {
-		// Create the qortal-backup folder if it doesn't exist
-		Path backupPath = Paths.get("qortal-backup");
-		try {
-			Files.createDirectories(backupPath);
-		} catch (IOException e) {
-			LOGGER.info("Unable to create backup folder");
-			throw new DataException("Unable to create backup folder");
-		}
-
-		try {
-			// Load trade bot data
-			List<TradeBotData> allTradeBotData = this.getCrossChainRepository().getAllTradeBotData();
-			JSONArray allTradeBotDataJson = new JSONArray();
-			for (TradeBotData tradeBotData : allTradeBotData) {
-				JSONObject tradeBotDataJson = tradeBotData.toJson();
-				allTradeBotDataJson.put(tradeBotDataJson);
-			}
-
-			// We need to combine existing TradeBotStates data before overwriting
-			String fileName = "qortal-backup/TradeBotStates.json";
-			File tradeBotStatesBackupFile = new File(fileName);
-			if (tradeBotStatesBackupFile.exists()) {
-				String jsonString = new String(Files.readAllBytes(Paths.get(fileName)));
-				JSONArray allExistingTradeBotData = new JSONArray(jsonString);
-				Iterator<Object> iterator = allExistingTradeBotData.iterator();
-				while(iterator.hasNext()) {
-					JSONObject existingTradeBotData = (JSONObject)iterator.next();
-					String existingTradePrivateKey = (String) existingTradeBotData.get("tradePrivateKey");
-						// Check if we already have an entry for this trade
-						boolean found = allTradeBotData.stream().anyMatch(tradeBotData -> Base58.encode(tradeBotData.getTradePrivateKey()).equals(existingTradePrivateKey));
-						if (found == false)
-							// We need to add this to our list
-							allTradeBotDataJson.put(existingTradeBotData);
-				}
-			}
-
-			FileWriter writer = new FileWriter(fileName);
-			writer.write(allTradeBotDataJson.toString());
-			writer.close();
-			LOGGER.info("Exported sensitive/node-local data: trade bot states");
-
-		} catch (DataException | IOException e) {
-			throw new DataException("Unable to export trade bot states from repository");
-		}
+		HSQLDBImportExport.backupTradeBotStates(this, null);
+		HSQLDBImportExport.backupMintingAccounts(this);
 	}
 
 	@Override
-	public void importDataFromFile(String filename) throws DataException {
-		LOGGER.info(() -> String.format("Importing data into repository from %s", filename));
-		try {
-			String jsonString = new String(Files.readAllBytes(Paths.get(filename)));
-			JSONArray tradeBotDataToImport = new JSONArray(jsonString);
-			Iterator<Object> iterator = tradeBotDataToImport.iterator();
-			while(iterator.hasNext()) {
-				JSONObject tradeBotDataJson = (JSONObject)iterator.next();
-				TradeBotData tradeBotData = TradeBotData.fromJson(tradeBotDataJson);
-				this.getCrossChainRepository().save(tradeBotData);
-			}
-		} catch (IOException e) {
-			throw new DataException("Unable to import sensitive/node-local trade bot states to repository: " + e.getMessage());
-		}
-		LOGGER.info(() -> String.format("Imported trade bot states into repository from %s", filename));
+	public void importDataFromFile(String filename) throws DataException, IOException {
+		HSQLDBImportExport.importDataFromFile(filename, this);
 	}
 
 	@Override
@@ -541,22 +499,22 @@ public class HSQLDBRepository implements Repository {
 			return matcher.group(2);
 	}
 
-	private static String buildBackupUrl(String dbPathname) {
+	private static String buildBackupUrl(String dbPathname, String backupName) {
 		Path oldRepoPath = Paths.get(dbPathname);
 		Path oldRepoDirPath = oldRepoPath.getParent();
 		Path oldRepoFilePath = oldRepoPath.getFileName();
 
 		// Try to open backup. We need to remove "create=true" and insert "backup" dir before final filename.
-		String backupUrlTemplate = "jdbc:hsqldb:file:%s%sbackup%s%s;create=false;hsqldb.full_log_replay=true";
-		return String.format(backupUrlTemplate, oldRepoDirPath.toString(), File.separator, File.separator, oldRepoFilePath.toString());
+		String backupUrlTemplate = "jdbc:hsqldb:file:%s%s%s%s%s;create=false;hsqldb.full_log_replay=true";
+		return String.format(backupUrlTemplate, oldRepoDirPath.toString(), File.separator, backupName, File.separator, oldRepoFilePath.toString());
 	}
 
-	/* package */ static void attemptRecovery(String connectionUrl) throws DataException {
+	/* package */ static void attemptRecovery(String connectionUrl, String name) throws DataException {
 		String dbPathname = getDbPathname(connectionUrl);
 		if (dbPathname == null)
 			throw new DataException("Unable to locate repository for backup?");
 
-		String backupUrl = buildBackupUrl(dbPathname);
+		String backupUrl = buildBackupUrl(dbPathname, name);
 		Path oldRepoDirPath = Paths.get(dbPathname).getParent();
 
 		// Attempt connection to backup to see if it is viable
@@ -1059,4 +1017,51 @@ public class HSQLDBRepository implements Repository {
 		return DEADLOCK_ERROR_CODE.equals(e.getErrorCode());
 	}
 
+	private int otherTransactionsCount() throws DataException {
+		// We can only perform a CHECKPOINT if no other HSQLDB session is mid-transaction,
+		// otherwise the CHECKPOINT blocks for COMMITs and other threads can't open HSQLDB sessions
+		// due to HSQLDB blocking until CHECKPOINT finishes - i.e. deadlock
+		String sql = "SELECT COUNT(*) "
+				+ "FROM Information_schema.system_sessions "
+				+ "WHERE transaction = TRUE AND session_id != ?";
+		try {
+			PreparedStatement pstmt = this.cachePreparedStatement(sql);
+			pstmt.setLong(1, this.sessionId);
+
+			if (!pstmt.execute())
+				throw new DataException("Unable to check repository session status");
+
+			try (ResultSet resultSet = pstmt.getResultSet()) {
+				if (resultSet == null || !resultSet.next())
+					// Failed to even find HSQLDB session info!
+					throw new DataException("No results when checking repository session status");
+
+				int transactionCount = resultSet.getInt(1);
+
+				return transactionCount;
+			}
+		} catch (SQLException e) {
+			throw new DataException("Unable to check repository session status", e);
+		}
+	}
+
+	private void blockUntilNoOtherTransactions(Long timeout) throws DataException, TimeoutException {
+		try {
+			long startTime = System.currentTimeMillis();
+			while (this.otherTransactionsCount() > 0) {
+				// Wait and try again
+				LOGGER.debug("Waiting for repository...");
+				Thread.sleep(1000L);
+
+				if (timeout != null) {
+					if (System.currentTimeMillis() - startTime >= timeout) {
+						throw new TimeoutException("Timed out waiting for repository to become available");
+					}
+				}
+			}
+		} catch (InterruptedException e) {
+			throw new DataException("Interrupted before repository became available");
+		}
+	}
+
 }

src/main/java/org/qortal/repository/hsqldb/HSQLDBRepositoryFactory.java

@@ -54,7 +54,7 @@ public class HSQLDBRepositoryFactory implements RepositoryFactory {
 				throw new DataException("Unable to read repository: " + e.getMessage(), e);
 
 			// Attempt recovery?
-			HSQLDBRepository.attemptRecovery(connectionUrl);
+			HSQLDBRepository.attemptRecovery(connectionUrl, "backup");
 		}
 
 		this.connectionPool = new HSQLDBPool(Settings.getInstance().getRepositoryConnectionPoolSize());

src/main/java/org/qortal/settings/Settings.java

@@ -5,6 +5,7 @@ import java.io.FileNotFoundException;
 import java.io.FileReader;
 import java.io.IOException;
 import java.io.Reader;
+import java.util.List;
 import java.util.Locale;
 
 import javax.xml.bind.JAXBContext;
@@ -68,6 +69,9 @@ public class Settings {
 	};
 	private Boolean apiRestricted;
 	private String apiKey = null;
+	/** Whether to disable API key or loopback address checking
+	 * IMPORTANT: do not disable for shared nodes or low-security local networks */
+	private boolean apiKeyDisabled = false;
 	private boolean apiLoggingEnabled = false;
 	private boolean apiDocumentationEnabled = false;
 	// Both of these need to be set for API to use SSL
@@ -86,6 +90,12 @@ public class Settings {
 	private long repositoryBackupInterval = 0; // ms
 	/** Whether to show a notification when we backup repository. */
 	private boolean showBackupNotification = false;
+	/** Minimum time between repository maintenance attempts (ms) */
+	private long repositoryMaintenanceMinInterval = 3 * 24 * 60 * 60 * 1000L; // 3 days (ms) default
+	/** Maximum time between repository maintenance attempts (ms) (0 if disabled). */
+	private long repositoryMaintenanceMaxInterval = 14 * 24 * 60 * 60 * 1000L; // 14 days (ms) default
+	/** Whether to show a notification when we run scheduled maintenance. */
+	private boolean showMaintenanceNotification = false;
 	/** How long between repository checkpoints (ms). */
 	private long repositoryCheckpointInterval = 60 * 60 * 1000L; // 1 hour (ms) default
 	/** Whether to show a notification when we perform repository 'checkpoint'. */
@@ -94,7 +104,7 @@ public class Settings {
 	private int blockCacheSize = 10;
 
 	/** How long to keep old, full, AT state data (ms). */
-	private long atStatesMaxLifetime = 2 * 7 * 24 * 60 * 60 * 1000L; // milliseconds
+	private long atStatesMaxLifetime = 5 * 24 * 60 * 60 * 1000L; // milliseconds
 	/** How often to attempt AT state trimming (ms). */
 	private long atStatesTrimInterval = 5678L; // milliseconds
 	/** Block height range to scan for trimmable AT states.<br>
@@ -109,6 +119,36 @@ public class Settings {
 	 * This has a significant effect on execution time. */
 	private int onlineSignaturesTrimBatchSize = 100; // blocks
 
+
+	/** Whether we should prune old data to reduce database size
+	 * This prevents the node from being able to serve older blocks */
+	private boolean topOnly = false;
+	/** The amount of recent blocks we should keep when pruning */
+	private int pruneBlockLimit = 1450;
+
+	/** How often to attempt AT state pruning (ms). */
+	private long atStatesPruneInterval = 3219L; // milliseconds
+	/** Block height range to scan for prunable AT states.<br>
+	 * This has a significant effect on execution time. */
+	private int atStatesPruneBatchSize = 25; // blocks
+
+	/** How often to attempt block pruning (ms). */
+	private long blockPruneInterval = 3219L; // milliseconds
+	/** Block height range to scan for prunable blocks.<br>
+	 * This has a significant effect on execution time. */
+	private int blockPruneBatchSize = 10000; // blocks
+
+
+	/** Whether we should archive old data to reduce the database size */
+	private boolean archiveEnabled = true;
+	/** How often to attempt archiving (ms). */
+	private long archiveInterval = 7171L; // milliseconds
+
+
+	/** Whether to automatically bootstrap instead of syncing from genesis */
+	private boolean bootstrap = true;
+
+
 	// Peer-to-peer related
 	private boolean isTestNet = false;
 	/** Port number for inbound peer-to-peer connections. */
@@ -154,6 +194,20 @@ public class Settings {
 	private String repositoryPath = "db";
 	/** Repository connection pool size. Needs to be a bit bigger than maxNetworkThreadPoolSize */
 	private int repositoryConnectionPoolSize = 100;
+	private List<String> fixedNetwork;
+
+	// Export/import
+	private String exportPath = "qortal-backup";
+
+	// Bootstrap
+	private String bootstrapFilenamePrefix = "";
+
+	// Bootstrap sources
+	private String[] bootstrapHosts = new String[] {
+			"http://bootstrap.qortal.org",
+			"http://bootstrap2.qortal.org",
+			"http://cinfu1.crowetic.com"
+	};
 
 	// Auto-update sources
 	private String[] autoUpdateRepos = new String[] {
@@ -356,6 +410,10 @@ public class Settings {
 		return this.apiKey;
 	}
 
+	public boolean isApiKeyDisabled() {
+		return this.apiKeyDisabled;
+	}
+
 	public boolean isApiLoggingEnabled() {
 		return this.apiLoggingEnabled;
 	}
@@ -469,6 +527,14 @@ public class Settings {
 		return this.repositoryConnectionPoolSize;
 	}
 
+	public String getExportPath() {
+		return this.exportPath;
+	}
+
+	public String getBootstrapFilenamePrefix() {
+		return this.bootstrapFilenamePrefix;
+	}
+
 	public boolean isAutoUpdateEnabled() {
 		return this.autoUpdateEnabled;
 	}
@@ -477,6 +543,10 @@ public class Settings {
 		return this.autoUpdateRepos;
 	}
 
+	public String[] getBootstrapHosts() {
+		return this.bootstrapHosts;
+	}
+
 	public String getListsPath() {
 		return this.listsPath;
 	}
@@ -497,6 +567,18 @@ public class Settings {
 		return this.showBackupNotification;
 	}
 
+	public long getRepositoryMaintenanceMinInterval() {
+		return this.repositoryMaintenanceMinInterval;
+	}
+
+	public long getRepositoryMaintenanceMaxInterval() {
+		return this.repositoryMaintenanceMaxInterval;
+	}
+
+	public boolean getShowMaintenanceNotification() {
+		return this.showMaintenanceNotification;
+	}
+
 	public long getRepositoryCheckpointInterval() {
 		return this.repositoryCheckpointInterval;
 	}
@@ -505,6 +587,10 @@ public class Settings {
 		return this.showCheckpointNotification;
 	}
 
+	public List<String> getFixedNetwork() {
+		return fixedNetwork;
+	}
+
 	public long getAtStatesMaxLifetime() {
 		return this.atStatesMaxLifetime;
 	}
@@ -529,4 +615,45 @@ public class Settings {
 		return this.onlineSignaturesTrimBatchSize;
 	}
 
+	public boolean isTopOnly() {
+		return this.topOnly;
+	}
+
+	public int getPruneBlockLimit() {
+		return this.pruneBlockLimit;
+	}
+
+	public long getAtStatesPruneInterval() {
+		return this.atStatesPruneInterval;
+	}
+
+	public int getAtStatesPruneBatchSize() {
+		return this.atStatesPruneBatchSize;
+	}
+
+	public long getBlockPruneInterval() {
+		return this.blockPruneInterval;
+	}
+
+	public int getBlockPruneBatchSize() {
+		return this.blockPruneBatchSize;
+	}
+
+
+	public boolean isArchiveEnabled() {
+		if (this.topOnly) {
+			return false;
+		}
+		return this.archiveEnabled;
+	}
+
+	public long getArchiveInterval() {
+		return this.archiveInterval;
+	}
+
+
+	public boolean getBootstrap() {
+		return this.bootstrap;
+	}
+
 }

src/main/java/org/qortal/transaction/AccountFlagsTransaction.java

@@ -48,6 +48,11 @@ public class AccountFlagsTransaction extends Transaction {
 		return ValidationResult.NO_FLAG_PERMISSION;
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public void process() throws DataException {
 		Account target = this.getTarget();

src/main/java/org/qortal/transaction/AccountLevelTransaction.java

@@ -49,6 +49,11 @@ public class AccountLevelTransaction extends Transaction {
 		return ValidationResult.NO_FLAG_PERMISSION;
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public void process() throws DataException {
 		Account target = getTarget();

src/main/java/org/qortal/transaction/AddGroupAdminTransaction.java

@@ -84,6 +84,11 @@ public class AddGroupAdminTransaction extends Transaction {
 		return ValidationResult.OK;
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public void process() throws DataException {
 		// Update Group adminship
@@ -98,4 +103,4 @@ public class AddGroupAdminTransaction extends Transaction {
 		group.unpromoteToAdmin(this.addGroupAdminTransactionData);
 	}
 
-}
+}

src/main/java/org/qortal/transaction/ArbitraryTransaction.java

@@ -60,6 +60,11 @@ public class ArbitraryTransaction extends Transaction {
 				arbitraryTransactionData.getFee());
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public void process() throws DataException {
 		// Wrap and delegate payment processing to Payment class.

src/main/java/org/qortal/transaction/AtTransaction.java

@@ -80,6 +80,11 @@ public class AtTransaction extends Transaction {
 		return Arrays.equals(atAccount.getLastReference(), atTransactionData.getReference());
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public ValidationResult isValid() throws DataException {
 		// Check recipient address is valid

src/main/java/org/qortal/transaction/BuyNameTransaction.java

@@ -6,6 +6,7 @@ import java.util.List;
 import org.qortal.account.Account;
 import org.qortal.asset.Asset;
 import org.qortal.block.BlockChain;
+import org.qortal.controller.repository.NamesDatabaseIntegrityCheck;
 import org.qortal.crypto.Crypto;
 import org.qortal.data.naming.NameData;
 import org.qortal.data.transaction.BuyNameTransactionData;
@@ -98,6 +99,17 @@ public class BuyNameTransaction extends Transaction {
 		return ValidationResult.OK;
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		BuyNameTransactionData buyNameTransactionData = (BuyNameTransactionData) transactionData;
+
+		// Rebuild this name in the Names table from the transaction history
+		// This is necessary because in some rare cases names can be missing from the Names table after registration
+		// but we have been unable to reproduce the issue and track down the root cause
+		NamesDatabaseIntegrityCheck namesDatabaseIntegrityCheck = new NamesDatabaseIntegrityCheck();
+		namesDatabaseIntegrityCheck.rebuildName(buyNameTransactionData.getName(), this.repository);
+	}
+
 	@Override
 	public void process() throws DataException {
 		// Buy Name

src/main/java/org/qortal/transaction/CancelAssetOrderTransaction.java

@@ -62,6 +62,11 @@ public class CancelAssetOrderTransaction extends Transaction {
 		return ValidationResult.OK;
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public void process() throws DataException {
 		// Mark Order as completed so no more trades can happen

src/main/java/org/qortal/transaction/CancelGroupBanTransaction.java

@@ -83,6 +83,11 @@ public class CancelGroupBanTransaction extends Transaction {
 		return ValidationResult.OK;
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public void process() throws DataException {
 		// Update Group Membership

src/main/java/org/qortal/transaction/CancelGroupInviteTransaction.java

@@ -83,6 +83,11 @@ public class CancelGroupInviteTransaction extends Transaction {
 		return ValidationResult.OK;
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public void process() throws DataException {
 		// Update Group Membership

src/main/java/org/qortal/transaction/CancelSellNameTransaction.java

@@ -79,6 +79,11 @@ public class CancelSellNameTransaction extends Transaction {
 
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public void process() throws DataException {
 		// Update Name

src/main/java/org/qortal/transaction/ChatTransaction.java

@@ -135,13 +135,18 @@ public class ChatTransaction extends Transaction {
 		return true;
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public ValidationResult isValid() throws DataException {
 		// Nonce checking is done via isSignatureValid() as that method is only called once per import
 
 		// Check for blacklisted author by address
 		ResourceListManager listManager = ResourceListManager.getInstance();
-		if (listManager.isAddressInBlacklist(this.chatTransactionData.getSender())) {
+		if (listManager.listContains("blacklist", "address", this.chatTransactionData.getSender())) {
 			return ValidationResult.ADDRESS_IN_BLACKLIST;
 		}
 

src/main/java/org/qortal/transaction/CreateAssetOrderTransaction.java

@@ -135,6 +135,11 @@ public class CreateAssetOrderTransaction extends Transaction {
 		return ValidationResult.OK;
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public void process() throws DataException {
 		// Order Id is transaction's signature

src/main/java/org/qortal/transaction/CreateGroupTransaction.java

@@ -92,6 +92,11 @@ public class CreateGroupTransaction extends Transaction {
 		return ValidationResult.OK;
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public void process() throws DataException {
 		// Create Group

src/main/java/org/qortal/transaction/CreatePollTransaction.java

@@ -106,6 +106,11 @@ public class CreatePollTransaction extends Transaction {
 		return ValidationResult.OK;
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public void process() throws DataException {
 		// Publish poll to allow voting

src/main/java/org/qortal/transaction/DeployAtTransaction.java

@@ -203,6 +203,11 @@ public class DeployAtTransaction extends Transaction {
 		return ValidationResult.OK;
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public void process() throws DataException {
 		ensureATAddress(this.deployAtTransactionData);

src/main/java/org/qortal/transaction/GenesisTransaction.java

@@ -100,6 +100,11 @@ public class GenesisTransaction extends Transaction {
 		return ValidationResult.OK;
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public void process() throws DataException {
 		Account recipient = new Account(repository, this.genesisTransactionData.getRecipient());

src/main/java/org/qortal/transaction/GroupApprovalTransaction.java

@@ -66,6 +66,11 @@ public class GroupApprovalTransaction extends Transaction {
 		return ValidationResult.OK;
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public void process() throws DataException {
 		// Find previous approval decision (if any) by this admin for pending transaction

src/main/java/org/qortal/transaction/GroupBanTransaction.java

@@ -87,6 +87,11 @@ public class GroupBanTransaction extends Transaction {
 		return ValidationResult.OK;
 	}
 
+	@Override
+	public void preProcess() throws DataException {
+		// Nothing to do
+	}
+
 	@Override
 	public void process() throws DataException {
 		// Update Group Membership