Make sure to set Peer.isDataPeer() to false as well as true, to prevent bugs due to object reuse.

Also designate a peer as a "data peer" when making an outbound connection to request data from it.

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:{CACF3376-2BAD-4028-8FB7-896EB938A9AF} 1049:{7C3C3F91-A84E-4740-96F1-E4948E4F1C8E} 2052:{1A3E70EF-EC7A-4500-A3DF-9F63B0AF210F} 2057:{F6397B6B-FAC0-4A76-AA8B-98A56ECC9A50} " Type="16"/>
+    <ROW Property="ProductCode" Value="1033:{8C9CFB9D-BC4C-4142-A5A5-5551BF3B9467} 1049:{4A5BDDD9-ED71-431A-A46F-D19E9DE17216} 2052:{0B9DCE00-BE23-434D-BD6A-1CFA6AB3CA43} 2057:{23D81967-556A-41B8-9981-A739E2820624} " Type="16"/>
     <ROW Property="ProductLanguage" Value="2057"/>
     <ROW Property="ProductName" Value="Qortal"/>
-    <ROW Property="ProductVersion" Value="3.2.1" Type="32"/>
+    <ROW Property="ProductVersion" Value="3.2.5" 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="{25A8E4DC-F9CC-4CE3-B193-56F22590C19C}" Directory_="APPDIR" Attributes="260" KeyPath="DisplayName" Options="1"/>
+    <ROW Component="AI_CustomARPName" ComponentId="{D5A1DC7D-914F-4425-8BA6-A1AE05D0F361}" 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>3.2.2</version>
+	<version>3.2.5</version>
 	<packaging>jar</packaging>
 	<properties>
 		<skipTests>true</skipTests>
@@ -21,6 +21,8 @@
 		<dagger.version>1.2.2</dagger.version>
 		<guava.version>28.1-jre</guava.version>
 		<hsqldb.version>2.5.1</hsqldb.version>
+		<homoglyph.version>1.2.1</homoglyph.version>
+		<icu4j.version>70.1</icu4j.version>
 		<upnp.version>1.1</upnp.version>
 		<jersey.version>2.29.1</jersey.version>
 		<jetty.version>9.4.29.v20200521</jetty.version>
@@ -568,7 +570,18 @@
 		<dependency>
 			<groupId>net.codebox</groupId>
 			<artifactId>homoglyph</artifactId>
-			<version>1.2.0</version>
+			<version>${homoglyph.version}</version>
+		</dependency>
+		<!-- Unicode support -->
+		<dependency>
+			<groupId>com.ibm.icu</groupId>
+			<artifactId>icu4j</artifactId>
+			<version>${icu4j.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.ibm.icu</groupId>
+			<artifactId>icu4j-charset</artifactId>
+			<version>${icu4j.version}</version>
 		</dependency>
 		<!-- Jetty -->
 		<dependency>

src/main/java/org/qortal/account/Account.java

@@ -205,6 +205,12 @@ public class Account {
 		return false;
 	}
 
+	/** Returns account's blockMinted (0+) or null if account not found in repository. */
+	public Integer getBlocksMinted() throws DataException {
+		return this.repository.getAccountRepository().getMintedBlockCount(this.address);
+	}
+
+
 	/** Returns whether account can build reward-shares.
 	 * <p>
 	 * To be able to create reward-shares, the account needs to pass at least one of these tests:<br>

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

@@ -381,6 +381,10 @@ public class AdminResource {
 			) @QueryParam("limit") Integer limit, @Parameter(
 				ref = "offset"
 			) @QueryParam("offset") Integer offset, @Parameter(
+				name = "tail",
+				description = "Fetch most recent log lines",
+				schema = @Schema(type = "boolean")
+			) @QueryParam("tail") Boolean tail, @Parameter(
 				ref = "reverse"
 			) @QueryParam("reverse") Boolean reverse) {
 		LoggerContext loggerContext = (LoggerContext) LogManager.getContext();
@@ -396,6 +400,13 @@ public class AdminResource {
 			if (reverse != null && reverse)
 				logLines = Lists.reverse(logLines);
 
+			// Tail mode - return the last X lines (where X = limit)
+			if (tail != null && tail) {
+				if (limit != null && limit > 0) {
+					offset = logLines.size() - limit;
+				}
+			}
+
 			// offset out of bounds?
 			if (offset != null && (offset < 0 || offset >= logLines.size()))
 				return "";
@@ -416,7 +427,7 @@ public class AdminResource {
 
 			limit = Math.min(limit, logLines.size());
 
-			logLines.subList(limit - 1, logLines.size()).clear();
+			logLines.subList(limit, logLines.size()).clear();
 
 			return String.join("\n", logLines);
 		} catch (IOException e) {
@@ -588,10 +599,6 @@ public class AdminResource {
 	public String importRepository(@HeaderParam(Security.API_KEY_HEADER) String apiKey, String filename) {
 		Security.checkApiCallAllowed(request);
 
-		// Hard-coded because it's too dangerous to allow user-supplied filenames in weaker security contexts
-		if (Settings.getInstance().getApiKey() == null)
-			filename = "qortal-backup/TradeBotStates.json";
-
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			ReentrantLock blockchainLock = Controller.getInstance().getBlockchainLock();
 

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

@@ -1267,13 +1267,19 @@ public class ArbitraryResource {
 		// Determine and add the status of each resource
 		List<ArbitraryResourceInfo> updatedResources = new ArrayList<>();
 		for (ArbitraryResourceInfo resourceInfo : resources) {
-			ArbitraryDataResource resource = new ArbitraryDataResource(resourceInfo.name, ResourceIdType.NAME,
-					resourceInfo.service, resourceInfo.identifier);
-			ArbitraryResourceStatus status = resource.getStatus(true);
-			if (status != null) {
-				resourceInfo.status = status;
+			try {
+				ArbitraryDataResource resource = new ArbitraryDataResource(resourceInfo.name, ResourceIdType.NAME,
+						resourceInfo.service, resourceInfo.identifier);
+				ArbitraryResourceStatus status = resource.getStatus(true);
+				if (status != null) {
+					resourceInfo.status = status;
+				}
+				updatedResources.add(resourceInfo);
+
+			} catch (Exception e) {
+				// Catch and log all exceptions, since some systems are experiencing 500 errors when including statuses
+				LOGGER.info("Caught exception when adding status to resource %s: %s", resourceInfo, e.toString());
 			}
-			updatedResources.add(resourceInfo);
 		}
 		return updatedResources;
 	}

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

@@ -98,7 +98,15 @@ public class GroupsResource {
 		ref = "reverse"
 	) @QueryParam("reverse") Boolean reverse) {
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			return repository.getGroupRepository().getAllGroups(limit, offset, reverse);
+			List<GroupData> allGroupData = repository.getGroupRepository().getAllGroups(limit, offset, reverse);
+			allGroupData.forEach(groupData -> {
+				try {
+					groupData.memberCount = repository.getGroupRepository().countGroupMembers(groupData.getGroupId());
+				} catch (DataException e) {
+					// Exclude memberCount for this group
+				}
+			});
+			return allGroupData;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -150,7 +158,15 @@ public class GroupsResource {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			return repository.getGroupRepository().getGroupsWithMember(member);
+			List<GroupData> allGroupData = repository.getGroupRepository().getGroupsWithMember(member);
+			allGroupData.forEach(groupData -> {
+				try {
+					groupData.memberCount = repository.getGroupRepository().countGroupMembers(groupData.getGroupId());
+				} catch (DataException e) {
+					// Exclude memberCount for this group
+				}
+			});
+			return allGroupData;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -177,6 +193,7 @@ public class GroupsResource {
 			if (groupData == null)
 				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.GROUP_UNKNOWN);
 
+			groupData.memberCount = repository.getGroupRepository().countGroupMembers(groupId);
 			return groupData;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
@@ -922,4 +939,4 @@ public class GroupsResource {
 		}
 	}
 
-}
+}

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

@@ -20,6 +20,11 @@ import javax.ws.rs.*;
 import javax.ws.rs.core.Context;
 import javax.ws.rs.core.MediaType;
 
+import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.core.config.Configuration;
+import org.apache.logging.log4j.core.config.LoggerConfig;
+import org.apache.logging.log4j.core.LoggerContext;
 import org.qortal.api.*;
 import org.qortal.api.model.ConnectedPeer;
 import org.qortal.api.model.PeersSummary;
@@ -127,9 +132,29 @@ public class PeersResource {
 		}
 	)
 	@SecurityRequirement(name = "apiKey")
-	public ExecuteProduceConsume.StatsSnapshot getEngineStats(@HeaderParam(Security.API_KEY_HEADER) String apiKey) {
+	public ExecuteProduceConsume.StatsSnapshot getEngineStats(@HeaderParam(Security.API_KEY_HEADER) String apiKey, @QueryParam("newLoggingLevel") Level newLoggingLevel) {
 		Security.checkApiCallAllowed(request);
 
+		if (newLoggingLevel != null) {
+			final LoggerContext ctx = (LoggerContext) LogManager.getContext(false);
+			final Configuration config = ctx.getConfiguration();
+
+			String epcClassName = "org.qortal.network.Network.NetworkProcessor";
+			LoggerConfig loggerConfig = config.getLoggerConfig(epcClassName);
+			LoggerConfig specificConfig = loggerConfig;
+
+			// We need a specific configuration for this logger,
+			// otherwise we would change the level of all other loggers
+			// having the original configuration as parent as well
+			if (!loggerConfig.getName().equals(epcClassName)) {
+				specificConfig = new LoggerConfig(epcClassName, newLoggingLevel, true);
+				specificConfig.setParent(loggerConfig);
+				config.addLogger(epcClassName, specificConfig);
+			}
+			specificConfig.setLevel(newLoggingLevel);
+			ctx.updateLoggers();
+		}
+
 		return Network.getInstance().getStatsSnapshot();
 	}
 

src/main/java/org/qortal/arbitrary/ArbitraryDataFile.java

@@ -93,10 +93,12 @@ public class ArbitraryDataFile {
         File outputFile = outputFilePath.toFile();
         try (FileOutputStream outputStream = new FileOutputStream(outputFile)) {
             outputStream.write(fileContent);
+            outputStream.close();
             this.filePath = outputFilePath;
             // Verify hash
-            if (!this.hash58.equals(this.digest58())) {
-                LOGGER.error("Hash {} does not match file digest {}", this.hash58, this.digest58());
+            String digest58 = this.digest58();
+            if (!this.hash58.equals(digest58)) {
+                LOGGER.error("Hash {} does not match file digest {} for signature: {}", this.hash58, digest58, Base58.encode(signature));
                 this.delete();
                 throw new DataException("Data file digest validation failed");
             }
@@ -478,6 +480,14 @@ public class ArbitraryDataFile {
 
             // Read the metadata
             List<byte[]> chunks = metadata.getChunks();
+
+            // If the chunks array is empty, then this resource has no chunks,
+            // so we must return false to avoid confusing the caller.
+            if (chunks.isEmpty()) {
+                return false;
+            }
+
+            // Otherwise, we need to check each chunk individually
             for (byte[] chunkHash : chunks) {
                 ArbitraryDataFileChunk chunk = ArbitraryDataFileChunk.fromHash(chunkHash, this.signature);
                 if (!chunk.exists()) {

src/main/java/org/qortal/at/QortalATAPI.java

@@ -551,7 +551,7 @@ public class QortalATAPI extends API {
 	 * <p>
 	 * Otherwise, assume B is a public key.
 	 */
-	private Account getAccountFromB(MachineState state) {
+	/*package*/ Account getAccountFromB(MachineState state) {
 		byte[] bBytes = this.getB(state);
 
 		if ((bBytes[0] == Crypto.ADDRESS_VERSION || bBytes[0] == Crypto.AT_ADDRESS_VERSION)

src/main/java/org/qortal/at/QortalFunctionCode.java

@@ -10,9 +10,11 @@ import org.ciyam.at.ExecutionException;
 import org.ciyam.at.FunctionData;
 import org.ciyam.at.IllegalFunctionCodeException;
 import org.ciyam.at.MachineState;
+import org.qortal.account.Account;
 import org.qortal.crosschain.Bitcoin;
 import org.qortal.crypto.Crypto;
 import org.qortal.data.transaction.TransactionData;
+import org.qortal.repository.DataException;
 import org.qortal.settings.Settings;
 
 /**
@@ -160,6 +162,68 @@ public enum QortalFunctionCode {
 		protected void postCheckExecute(FunctionData functionData, MachineState state, short rawFunctionCode) throws ExecutionException {
 			convertAddressInB(Crypto.ADDRESS_VERSION, state);
 		}
+	},
+	/**
+	 * Returns account level of account in B.<br>
+	 * <tt>0x0520</tt><br>
+	 * B should contain either Qortal address or public key,<br>
+	 * e.g. as a result of calling function {@link org.ciyam.at.FunctionCode#PUT_ADDRESS_FROM_TX_IN_A_INTO_B}</code>.
+	 * <p></p>
+	 * Returns account level, or -1 if account unknown.
+	 * <p></p>
+	 * @see QortalATAPI#getAccountFromB(MachineState)
+	 */
+	GET_ACCOUNT_LEVEL_FROM_ACCOUNT_IN_B(0x0520, 0, true) {
+		@Override
+		protected void postCheckExecute(FunctionData functionData, MachineState state, short rawFunctionCode) throws ExecutionException {
+			QortalATAPI api = (QortalATAPI) state.getAPI();
+			Account account = api.getAccountFromB(state);
+
+			Integer accountLevel = null;
+
+			if (account != null) {
+				try {
+					accountLevel = account.getLevel();
+				} catch (DataException e) {
+					throw new RuntimeException("AT API unable to fetch account level?", e);
+				}
+			}
+
+			functionData.returnValue = accountLevel != null
+					? accountLevel.longValue()
+					: -1;
+		}
+	},
+	/**
+	 * Returns account's minted block count of account in B.<br>
+	 * <tt>0x0521</tt><br>
+	 * B should contain either Qortal address or public key,<br>
+	 * e.g. as a result of calling function {@link org.ciyam.at.FunctionCode#PUT_ADDRESS_FROM_TX_IN_A_INTO_B}</code>.
+	 * <p></p>
+	 * Returns account level, or -1 if account unknown.
+	 * <p></p>
+	 * @see QortalATAPI#getAccountFromB(MachineState)
+	 */
+	GET_BLOCKS_MINTED_FROM_ACCOUNT_IN_B(0x0521, 0, true) {
+		@Override
+		protected void postCheckExecute(FunctionData functionData, MachineState state, short rawFunctionCode) throws ExecutionException {
+			QortalATAPI api = (QortalATAPI) state.getAPI();
+			Account account = api.getAccountFromB(state);
+
+			Integer blocksMinted = null;
+
+			if (account != null) {
+				try {
+					blocksMinted = account.getBlocksMinted();
+				} catch (DataException e) {
+					throw new RuntimeException("AT API unable to fetch account's minted block count?", e);
+				}
+			}
+
+			functionData.returnValue = blocksMinted != null
+					? blocksMinted.longValue()
+					: -1;
+		}
 	};
 
 	public final short value;

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

@@ -73,9 +73,13 @@ public class BlockChain {
 	}
 
 	// Custom transaction fees
-	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
-	private long nameRegistrationUnitFee;
-	private long nameRegistrationUnitFeeTimestamp;
+	/** Unit fees by transaction timestamp */
+	public static class UnitFeesByTimestamp {
+		public long timestamp;
+		@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+		public long fee;
+	}
+	private List<UnitFeesByTimestamp> nameRegistrationUnitFees;
 
 	/** Map of which blockchain features are enabled when (height/timestamp) */
 	@XmlJavaTypeAdapter(StringLongMapXmlAdapter.class)
@@ -306,16 +310,6 @@ public class BlockChain {
 		return this.maxBlockSize;
 	}
 
-	// Custom transaction fees
-	public long getNameRegistrationUnitFee() {
-		return this.nameRegistrationUnitFee;
-	}
-
-	public long getNameRegistrationUnitFeeTimestamp() {
-		// FUTURE: we could use a separate structure to indicate fee adjustments for different transaction types
-		return this.nameRegistrationUnitFeeTimestamp;
-	}
-
 	/** Returns true if approval-needing transaction types require a txGroupId other than NO_GROUP. */
 	public boolean getRequireGroupForApproval() {
 		return this.requireGroupForApproval;
@@ -430,6 +424,15 @@ public class BlockChain {
 		throw new IllegalStateException(String.format("No block timing info available for height %d", ourHeight));
 	}
 
+	public long getNameRegistrationUnitFeeAtTimestamp(long ourTimestamp) {
+		for (int i = nameRegistrationUnitFees.size() - 1; i >= 0; --i)
+			if (nameRegistrationUnitFees.get(i).timestamp <= ourTimestamp)
+				return nameRegistrationUnitFees.get(i).fee;
+
+		// Default to system-wide unit fee
+		return this.getUnitFee();
+	}
+
 	/** Validate blockchain config read from JSON */
 	private void validateConfig() {
 		if (this.genesisInfo == null)

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

@@ -219,7 +219,7 @@ public class BlockMinter extends Thread {
 					// The last iteration found a higher weight block in the network, so sleep for a while
 					// to allow is to sync the higher weight chain. We are sleeping here rather than when
 					// detected as we don't want to hold the blockchain lock open.
-					LOGGER.info("Sleeping for 10 seconds...");
+					LOGGER.debug("Sleeping for 10 seconds...");
 					Thread.sleep(10 * 1000L);
 				}
 
@@ -328,13 +328,13 @@ public class BlockMinter extends Thread {
 							// If less than 30 seconds has passed since first detection the higher weight chain,
 							// we should skip our block submission to give us the opportunity to sync to the better chain
 							if (NTP.getTime() - timeOfLastLowWeightBlock < 30*1000L) {
-								LOGGER.info("Higher weight chain found in peers, so not signing a block this round");
-								LOGGER.info("Time since detected: {}", NTP.getTime() - timeOfLastLowWeightBlock);
+								LOGGER.debug("Higher weight chain found in peers, so not signing a block this round");
+								LOGGER.debug("Time since detected: {}ms", NTP.getTime() - timeOfLastLowWeightBlock);
 								continue;
 							}
 							else {
 								// More than 30 seconds have passed, so we should submit our block candidate anyway.
-								LOGGER.info("More than 30 seconds passed, so proceeding to submit block candidate...");
+								LOGGER.debug("More than 30 seconds passed, so proceeding to submit block candidate...");
 							}
 						}
 						else {

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

@@ -58,6 +58,7 @@ import org.qortal.repository.hsqldb.HSQLDBRepositoryFactory;
 import org.qortal.settings.Settings;
 import org.qortal.transaction.Transaction;
 import org.qortal.transaction.Transaction.TransactionType;
+import org.qortal.transform.TransformationException;
 import org.qortal.utils.*;
 
 public class Controller extends Thread {
@@ -573,15 +574,20 @@ public class Controller extends Thread {
 								MessageType.INFO);
 
 					LOGGER.info("Starting scheduled repository maintenance. This can take a while...");
-					try (final Repository repository = RepositoryManager.getRepository()) {
+					int attempts = 0;
+					while (attempts <= 5) {
+						try (final Repository repository = RepositoryManager.getRepository()) {
+							attempts++;
 
-						// Timeout if the database isn't ready for maintenance after 60 seconds
-						long timeout = 60 * 1000L;
-						repository.performPeriodicMaintenance(timeout);
+							// 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);
+							LOGGER.info("Scheduled repository maintenance completed");
+							break;
+						} catch (DataException | TimeoutException e) {
+							LOGGER.info("Scheduled repository maintenance failed. Retrying up to 5 times...", e);
+						}
 					}
 
 					// Get a new random interval
@@ -675,7 +681,7 @@ public class Controller extends Thread {
 	public static final Predicate<Peer> hasInferiorChainTip = peer -> {
 		final PeerChainTipData peerChainTipData = peer.getChainTipData();
 		final List<ByteArray> inferiorChainTips = Synchronizer.getInstance().inferiorChainSignatures;
-		return peerChainTipData == null || peerChainTipData.getLastBlockSignature() == null || inferiorChainTips.contains(new ByteArray(peerChainTipData.getLastBlockSignature()));
+		return peerChainTipData == null || peerChainTipData.getLastBlockSignature() == null || inferiorChainTips.contains(ByteArray.wrap(peerChainTipData.getLastBlockSignature()));
 	};
 
 	public static final Predicate<Peer> hasOldVersion = peer -> {
@@ -1203,7 +1209,7 @@ public class Controller extends Thread {
 		byte[] signature = getBlockMessage.getSignature();
 		this.stats.getBlockMessageStats.requests.incrementAndGet();
 
-		ByteArray signatureAsByteArray = new ByteArray(signature);
+		ByteArray signatureAsByteArray = ByteArray.wrap(signature);
 
 		CachedBlockMessage cachedBlockMessage = this.blockMessageCache.get(signatureAsByteArray);
 		int blockCacheSize = Settings.getInstance().getBlockCacheSize();
@@ -1213,7 +1219,7 @@ public class Controller extends Thread {
 			this.stats.getBlockMessageStats.cacheHits.incrementAndGet();
 
 			// We need to duplicate it to prevent multiple threads setting ID on the same message
-			CachedBlockMessage clonedBlockMessage = cachedBlockMessage.cloneWithNewId(message.getId());
+			CachedBlockMessage clonedBlockMessage = Message.cloneWithNewId(cachedBlockMessage, message.getId());
 
 			if (!peer.sendMessage(clonedBlockMessage))
 				peer.disconnect("failed to send block");
@@ -1272,7 +1278,6 @@ public class Controller extends Thread {
 			CachedBlockMessage blockMessage = new CachedBlockMessage(block);
 			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
@@ -1283,10 +1288,12 @@ public class Controller extends Thread {
 			if (getChainHeight() - blockData.getHeight() <= blockCacheSize) {
 				this.stats.getBlockMessageStats.cacheFills.incrementAndGet();
 
-				this.blockMessageCache.put(new ByteArray(blockData.getSignature()), blockMessage);
+				this.blockMessageCache.put(ByteArray.wrap(blockData.getSignature()), blockMessage);
 			}
 		} catch (DataException e) {
-			LOGGER.error(String.format("Repository issue while send block %s to peer %s", Base58.encode(signature), peer), e);
+			LOGGER.error(String.format("Repository issue while sending block %s to peer %s", Base58.encode(signature), peer), e);
+		} catch (TransformationException e) {
+			LOGGER.error(String.format("Serialization issue while sending block %s to peer %s", Base58.encode(signature), peer), e);
 		}
 	}
 

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

@@ -33,7 +33,7 @@ import org.qortal.network.message.GetBlockSummariesMessage;
 import org.qortal.network.message.GetSignaturesV2Message;
 import org.qortal.network.message.Message;
 import org.qortal.network.message.SignaturesMessage;
-import org.qortal.network.message.Message.MessageType;
+import org.qortal.network.message.MessageType;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
 import org.qortal.repository.RepositoryManager;
@@ -314,7 +314,7 @@ public class Synchronizer extends Thread {
 
 				case INFERIOR_CHAIN: {
 					// Update our list of inferior chain tips
-					ByteArray inferiorChainSignature = new ByteArray(peer.getChainTipData().getLastBlockSignature());
+					ByteArray inferiorChainSignature = ByteArray.wrap(peer.getChainTipData().getLastBlockSignature());
 					if (!inferiorChainSignatures.contains(inferiorChainSignature))
 						inferiorChainSignatures.add(inferiorChainSignature);
 
@@ -343,7 +343,7 @@ public class Synchronizer extends Thread {
 					// fall-through...
 				case NOTHING_TO_DO: {
 					// Update our list of inferior chain tips
-					ByteArray inferiorChainSignature = new ByteArray(peer.getChainTipData().getLastBlockSignature());
+					ByteArray inferiorChainSignature = ByteArray.wrap(peer.getChainTipData().getLastBlockSignature());
 					if (!inferiorChainSignatures.contains(inferiorChainSignature))
 						inferiorChainSignatures.add(inferiorChainSignature);
 
@@ -419,7 +419,7 @@ public class Synchronizer extends Thread {
 
 	public void addInferiorChainSignature(byte[] inferiorSignature) {
 		// Update our list of inferior chain tips
-		ByteArray inferiorChainSignature = new ByteArray(inferiorSignature);
+		ByteArray inferiorChainSignature = ByteArray.wrap(inferiorSignature);
 		if (!inferiorChainSignatures.contains(inferiorChainSignature))
 			inferiorChainSignatures.add(inferiorChainSignature);
 	}

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

@@ -12,6 +12,7 @@ import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
 import org.qortal.repository.RepositoryManager;
 import org.qortal.transaction.Transaction;
+import org.qortal.transform.TransformationException;
 import org.qortal.utils.Base58;
 import org.qortal.utils.NTP;
 
@@ -289,7 +290,9 @@ public class TransactionImporter extends Thread {
             if (!peer.sendMessage(transactionMessage))
                 peer.disconnect("failed to send transaction");
         } catch (DataException e) {
-            LOGGER.error(String.format("Repository issue while send transaction %s to peer %s", Base58.encode(signature), peer), e);
+            LOGGER.error(String.format("Repository issue while sending transaction %s to peer %s", Base58.encode(signature), peer), e);
+        } catch (TransformationException e) {
+            LOGGER.error(String.format("Serialization issue while sending transaction %s to peer %s", Base58.encode(signature), peer), e);
         }
     }
 

src/main/java/org/qortal/controller/arbitrary/ArbitraryDataFileListManager.java

@@ -283,8 +283,8 @@ public class ArbitraryDataFileListManager {
 
         LOGGER.debug(String.format("Sending data file list request for signature %s with %d hashes to %d peers...", signature58, hashCount, handshakedPeers.size()));
 
-        // FUTURE: send our address as requestingPeer once enough peers have switched to the new protocol
-        String requestingPeer = null; // Network.getInstance().getOurExternalIpAddressAndPort();
+        // Send our address as requestingPeer, to allow for potential direct connections with seeds/peers
+        String requestingPeer = Network.getInstance().getOurExternalIpAddressAndPort();
 
         // Build request
         Message getArbitraryDataFileListMessage = new GetArbitraryDataFileListMessage(signature, missingHashes, now, 0, requestingPeer);
@@ -511,18 +511,23 @@ public class ArbitraryDataFileListManager {
 
                     // Bump requestHops if it exists
                     if (requestHops != null) {
-                        arbitraryDataFileListMessage.setRequestHops(++requestHops);
+                        requestHops++;
                     }
 
+                    ArbitraryDataFileListMessage forwardArbitraryDataFileListMessage;
+
                     // Remove optional parameters if the requesting peer doesn't support it yet
                     // A message with less statistical data is better than no message at all
                     if (!requestingPeer.isAtLeastVersion(MIN_PEER_VERSION_FOR_FILE_LIST_STATS)) {
-                        arbitraryDataFileListMessage.removeOptionalStats();
+                        forwardArbitraryDataFileListMessage = new ArbitraryDataFileListMessage(signature, hashes);
+                    } else {
+                        forwardArbitraryDataFileListMessage = new ArbitraryDataFileListMessage(signature, hashes, requestTime, requestHops,
+                                arbitraryDataFileListMessage.getPeerAddress(), arbitraryDataFileListMessage.isRelayPossible());
                     }
 
                     // Forward to requesting peer
                     LOGGER.debug("Forwarding file list with {} hashes to requesting peer: {}", hashes.size(), requestingPeer);
-                    if (!requestingPeer.sendMessage(arbitraryDataFileListMessage)) {
+                    if (!requestingPeer.sendMessage(forwardArbitraryDataFileListMessage)) {
                         requestingPeer.disconnect("failed to forward arbitrary data file list");
                     }
                 }
@@ -631,6 +636,9 @@ public class ArbitraryDataFileListManager {
         // We should only respond if we have at least one hash
         if (hashes.size() > 0) {
 
+            // Firstly we should keep track of the requesting peer, to allow for potential direct connections later
+            ArbitraryDataFileManager.getInstance().addRecentDataRequest(requestingPeer);
+
             // We have all the chunks, so update requests map to reflect that we've sent it
             // There is no need to keep track of the request, as we can serve all the chunks
             if (allChunksExist) {
@@ -639,16 +647,19 @@ public class ArbitraryDataFileListManager {
             }
 
             String ourAddress = Network.getInstance().getOurExternalIpAddressAndPort();
-            ArbitraryDataFileListMessage arbitraryDataFileListMessage = new ArbitraryDataFileListMessage(signature,
-                    hashes, NTP.getTime(), 0, ourAddress, true);
-            arbitraryDataFileListMessage.setId(message.getId());
+            ArbitraryDataFileListMessage arbitraryDataFileListMessage;
 
             // Remove optional parameters if the requesting peer doesn't support it yet
             // A message with less statistical data is better than no message at all
             if (!peer.isAtLeastVersion(MIN_PEER_VERSION_FOR_FILE_LIST_STATS)) {
-                arbitraryDataFileListMessage.removeOptionalStats();
+                arbitraryDataFileListMessage = new ArbitraryDataFileListMessage(signature, hashes);
+            } else {
+                arbitraryDataFileListMessage = new ArbitraryDataFileListMessage(signature,
+                        hashes, NTP.getTime(), 0, ourAddress, true);
             }
 
+            arbitraryDataFileListMessage.setId(message.getId());
+
             if (!peer.sendMessage(arbitraryDataFileListMessage)) {
                 LOGGER.debug("Couldn't send list of hashes");
                 peer.disconnect("failed to send list of hashes");
@@ -670,8 +681,7 @@ public class ArbitraryDataFileListManager {
             // In relay mode - so ask our other peers if they have it
 
             long requestTime = getArbitraryDataFileListMessage.getRequestTime();
-            int requestHops = getArbitraryDataFileListMessage.getRequestHops();
-            getArbitraryDataFileListMessage.setRequestHops(++requestHops);
+            int requestHops = getArbitraryDataFileListMessage.getRequestHops() + 1;
             long totalRequestTime = now - requestTime;
 
             if (totalRequestTime < RELAY_REQUEST_MAX_DURATION) {
@@ -679,11 +689,13 @@ public class ArbitraryDataFileListManager {
                 if (requestHops < RELAY_REQUEST_MAX_HOPS) {
                     // Relay request hasn't reached the maximum number of hops yet, so can be rebroadcast
 
+                    Message relayGetArbitraryDataFileListMessage = new GetArbitraryDataFileListMessage(signature, hashes, requestTime, requestHops, requestingPeer);
+
                     LOGGER.debug("Rebroadcasting hash list request from peer {} for signature {} to our other peers... totalRequestTime: {}, requestHops: {}", peer, Base58.encode(signature), totalRequestTime, requestHops);
                     Network.getInstance().broadcast(
                             broadcastPeer -> broadcastPeer == peer ||
                                     Objects.equals(broadcastPeer.getPeerData().getAddress().getHost(), peer.getPeerData().getAddress().getHost())
-                                    ? null : getArbitraryDataFileListMessage);
+                                    ? null : relayGetArbitraryDataFileListMessage);
 
                 }
                 else {

src/main/java/org/qortal/controller/arbitrary/ArbitraryDataFileManager.java

@@ -1,5 +1,6 @@
 package org.qortal.controller.arbitrary;
 
+import com.google.common.net.InetAddresses;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.qortal.arbitrary.ArbitraryDataFile;
@@ -7,7 +8,6 @@ import org.qortal.controller.Controller;
 import org.qortal.data.arbitrary.ArbitraryDirectConnectionInfo;
 import org.qortal.data.arbitrary.ArbitraryFileListResponseInfo;
 import org.qortal.data.arbitrary.ArbitraryRelayInfo;
-import org.qortal.data.network.ArbitraryPeerData;
 import org.qortal.data.network.PeerData;
 import org.qortal.data.transaction.ArbitraryTransactionData;
 import org.qortal.network.Network;
@@ -55,6 +55,13 @@ public class ArbitraryDataFileManager extends Thread {
      */
     private List<ArbitraryDirectConnectionInfo> directConnectionInfo = Collections.synchronizedList(new ArrayList<>());
 
+    /**
+     * Map to keep track of peers requesting QDN data that we hold.
+     * Key = peer address string, value = time of last request.
+     * This allows for additional "burst" connections beyond existing limits.
+     */
+    private Map<String, Long> recentDataRequests = Collections.synchronizedMap(new HashMap<>());
+
 
     public static int MAX_FILE_HASH_RESPONSES = 1000;
 
@@ -109,6 +116,9 @@ public class ArbitraryDataFileManager extends Thread {
 
         final long directConnectionInfoMinimumTimestamp = now - ArbitraryDataManager.getInstance().ARBITRARY_DIRECT_CONNECTION_INFO_TIMEOUT;
         directConnectionInfo.removeIf(entry -> entry.getTimestamp() < directConnectionInfoMinimumTimestamp);
+
+        final long recentDataRequestMinimumTimestamp = now - ArbitraryDataManager.getInstance().ARBITRARY_RECENT_DATA_REQUESTS_TIMEOUT;
+        recentDataRequests.entrySet().removeIf(entry -> entry.getValue() < recentDataRequestMinimumTimestamp);
     }
 
 
@@ -140,7 +150,7 @@ public class ArbitraryDataFileManager extends Thread {
                     Long startTime = NTP.getTime();
                     ArbitraryDataFileMessage receivedArbitraryDataFileMessage = fetchArbitraryDataFile(peer, null, signature, hash, null);
                     Long endTime = NTP.getTime();
-                    if (receivedArbitraryDataFileMessage != null) {
+                    if (receivedArbitraryDataFileMessage != null && receivedArbitraryDataFileMessage.getArbitraryDataFile() != null) {
                         LOGGER.debug("Received data file {} from peer {}. Time taken: {} ms", receivedArbitraryDataFileMessage.getArbitraryDataFile().getHash58(), peer, (endTime-startTime));
                         receivedAtLeastOneFile = true;
 
@@ -187,7 +197,7 @@ public class ArbitraryDataFileManager extends Thread {
         ArbitraryDataFile existingFile = ArbitraryDataFile.fromHash(hash, signature);
         boolean fileAlreadyExists = existingFile.exists();
         String hash58 = Base58.encode(hash);
-        Message message = null;
+        ArbitraryDataFileMessage arbitraryDataFileMessage;
 
         // Fetch the file if it doesn't exist locally
         if (!fileAlreadyExists) {
@@ -195,10 +205,11 @@ public class ArbitraryDataFileManager extends Thread {
             arbitraryDataFileRequests.put(hash58, NTP.getTime());
             Message getArbitraryDataFileMessage = new GetArbitraryDataFileMessage(signature, hash);
 
+            Message response = null;
             try {
-                message = peer.getResponseWithTimeout(getArbitraryDataFileMessage, (int) ArbitraryDataManager.ARBITRARY_REQUEST_TIMEOUT);
+                response = peer.getResponseWithTimeout(getArbitraryDataFileMessage, (int) ArbitraryDataManager.ARBITRARY_REQUEST_TIMEOUT);
             } catch (InterruptedException e) {
-                // Will return below due to null message
+                // Will return below due to null response
             }
             arbitraryDataFileRequests.remove(hash58);
             LOGGER.trace(String.format("Removed hash %.8s from arbitraryDataFileRequests", hash58));
@@ -206,22 +217,24 @@ public class ArbitraryDataFileManager extends Thread {
             // We may need to remove the file list request, if we have all the files for this transaction
             this.handleFileListRequests(signature);
 
-            if (message == null) {
-                LOGGER.debug("Received null message from peer {}", peer);
+            if (response == null) {
+                LOGGER.debug("Received null response from peer {}", peer);
                 return null;
             }
-            if (message.getType() != Message.MessageType.ARBITRARY_DATA_FILE) {
-                LOGGER.debug("Received message with invalid type: {} from peer {}", message.getType(), peer);
+            if (response.getType() != MessageType.ARBITRARY_DATA_FILE) {
+                LOGGER.debug("Received response with invalid type: {} from peer {}", response.getType(), peer);
                 return null;
             }
-        }
-        else {
+
+            ArbitraryDataFileMessage peersArbitraryDataFileMessage = (ArbitraryDataFileMessage) response;
+            arbitraryDataFileMessage = new ArbitraryDataFileMessage(signature, peersArbitraryDataFileMessage.getArbitraryDataFile());
+        } else {
             LOGGER.debug(String.format("File hash %s already exists, so skipping the request", hash58));
+            arbitraryDataFileMessage = new ArbitraryDataFileMessage(signature, existingFile);
         }
-        ArbitraryDataFileMessage arbitraryDataFileMessage = (ArbitraryDataFileMessage) message;
 
         // We might want to forward the request to the peer that originally requested it
-        this.handleArbitraryDataFileForwarding(requestingPeer, message, originalMessage);
+        this.handleArbitraryDataFileForwarding(requestingPeer, arbitraryDataFileMessage, originalMessage);
 
         boolean isRelayRequest = (requestingPeer != null);
         if (isRelayRequest) {
@@ -488,6 +501,45 @@ public class ArbitraryDataFileManager extends Thread {
     }
 
 
+    // Peers requesting QDN data from us
+
+    /**
+     * Add an address string of a peer that is trying to request data from us.
+     * @param peerAddress
+     */
+    public void addRecentDataRequest(String peerAddress) {
+        if (peerAddress == null) {
+            return;
+        }
+
+        Long now = NTP.getTime();
+        if (now == null) {
+            return;
+        }
+
+        // Make sure to remove the port, since it isn't guaranteed to match next time
+        String[] parts = peerAddress.split(":");
+        if (parts.length == 0) {
+            return;
+        }
+        String host = parts[0];
+        if (!InetAddresses.isInetAddress(host)) {
+            // Invalid host
+            return;
+        }
+
+        this.recentDataRequests.put(host, now);
+    }
+
+    public boolean isPeerRequestingData(String peerAddressWithoutPort) {
+        return this.recentDataRequests.containsKey(peerAddressWithoutPort);
+    }
+
+    public boolean hasPendingDataRequest() {
+        return !this.recentDataRequests.isEmpty();
+    }
+
+
     // Network handlers
 
     public void onNetworkGetArbitraryDataFileMessage(Peer peer, Message message) {

src/main/java/org/qortal/controller/arbitrary/ArbitraryDataManager.java

@@ -47,6 +47,9 @@ public class ArbitraryDataManager extends Thread {
 	/** Maximum time to hold direct peer connection information */
 	public static final long ARBITRARY_DIRECT_CONNECTION_INFO_TIMEOUT = 2 * 60 * 1000L; // ms
 
+	/** Maximum time to hold information about recent data requests that we can fulfil */
+	public static final long ARBITRARY_RECENT_DATA_REQUESTS_TIMEOUT = 2 * 60 * 1000L; // ms
+
 	/** Maximum number of hops that an arbitrary signatures request is allowed to make */
 	private static int ARBITRARY_SIGNATURES_REQUEST_MAX_HOPS = 3;
 

src/main/java/org/qortal/controller/arbitrary/ArbitraryMetadataManager.java

@@ -216,9 +216,19 @@ public class ArbitraryMetadataManager {
 
         long timeSinceLastAttempt = NTP.getTime() - lastAttemptTimestamp;
 
-        // Allow a second attempt after 15 seconds, and another after 30 seconds
-        if (timeSinceLastAttempt > 15 * 1000L) {
-            // We haven't tried for at least 15 seconds
+        // Allow a second attempt after 60 seconds
+        if (timeSinceLastAttempt > 60 * 1000L) {
+            // We haven't tried for at least 60 seconds
+
+            if (networkBroadcastCount < 2) {
+                // We've made less than 2 total attempts
+                return true;
+            }
+        }
+
+        // Then allow another attempt after 60 minutes
+        if (timeSinceLastAttempt > 60 * 60 * 1000L) {
+            // We haven't tried for at least 60 minutes
 
             if (networkBroadcastCount < 3) {
                 // We've made less than 3 total attempts
@@ -226,22 +236,6 @@ public class ArbitraryMetadataManager {
             }
         }
 
-        // Then allow another 5 attempts, each 5 minutes apart
-        if (timeSinceLastAttempt > 5 * 60 * 1000L) {
-            // We haven't tried for at least 5 minutes
-
-            if (networkBroadcastCount < 5) {
-                // We've made less than 5 total attempts
-                return true;
-            }
-        }
-
-        // From then on, only try once every 24 hours, to reduce network spam
-        if (timeSinceLastAttempt > 24 * 60 * 60 * 1000L) {
-            // We haven't tried for at least 24 hours
-            return true;
-        }
-
         return false;
     }
 
@@ -344,9 +338,11 @@ public class ArbitraryMetadataManager {
                 Peer requestingPeer = request.getB();
                 if (requestingPeer != null) {
 
+                    ArbitraryMetadataMessage forwardArbitraryMetadataMessage = new ArbitraryMetadataMessage(signature, arbitraryMetadataMessage.getArbitraryMetadataFile());
+
                     // Forward to requesting peer
                     LOGGER.debug("Forwarding metadata to requesting peer: {}", requestingPeer);
-                    if (!requestingPeer.sendMessage(arbitraryMetadataMessage)) {
+                    if (!requestingPeer.sendMessage(forwardArbitraryMetadataMessage)) {
                         requestingPeer.disconnect("failed to forward arbitrary metadata");
                     }
                 }
@@ -429,8 +425,7 @@ public class ArbitraryMetadataManager {
             // In relay mode - so ask our other peers if they have it
 
             long requestTime = getArbitraryMetadataMessage.getRequestTime();
-            int requestHops = getArbitraryMetadataMessage.getRequestHops();
-            getArbitraryMetadataMessage.setRequestHops(++requestHops);
+            int requestHops = getArbitraryMetadataMessage.getRequestHops() + 1;
             long totalRequestTime = now - requestTime;
 
             if (totalRequestTime < RELAY_REQUEST_MAX_DURATION) {
@@ -438,11 +433,13 @@ public class ArbitraryMetadataManager {
                 if (requestHops < RELAY_REQUEST_MAX_HOPS) {
                     // Relay request hasn't reached the maximum number of hops yet, so can be rebroadcast
 
+                    Message relayGetArbitraryMetadataMessage = new GetArbitraryMetadataMessage(signature, requestTime, requestHops);
+
                     LOGGER.debug("Rebroadcasting metadata request from peer {} for signature {} to our other peers... totalRequestTime: {}, requestHops: {}", peer, Base58.encode(signature), totalRequestTime, requestHops);
                     Network.getInstance().broadcast(
                             broadcastPeer -> broadcastPeer == peer ||
                                     Objects.equals(broadcastPeer.getPeerData().getAddress().getHost(), peer.getPeerData().getAddress().getHost())
-                                    ? null : getArbitraryMetadataMessage);
+                                    ? null : relayGetArbitraryMetadataMessage);
 
                 }
                 else {

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

@@ -29,6 +29,15 @@ public class NamesDatabaseIntegrityCheck {
     private List<TransactionData> nameTransactions = new ArrayList<>();
 
     public int rebuildName(String name, Repository repository) {
+        return this.rebuildName(name, repository, null);
+    }
+
+    public int rebuildName(String name, Repository repository, List<String> referenceNames) {
+        // "referenceNames" tracks the linked names that have already been rebuilt, to prevent circular dependencies
+        if (referenceNames == null) {
+            referenceNames = new ArrayList<>();
+        }
+
         int modificationCount = 0;
         try {
             List<TransactionData> transactions = this.fetchAllTransactionsInvolvingName(name, repository);
@@ -56,7 +65,14 @@ public class NamesDatabaseIntegrityCheck {
                     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);
+
+                        if (!referenceNames.contains(name)) {
+                            referenceNames.add(name);
+                            this.rebuildName(updateNameTransactionData.getName(), repository, referenceNames);
+                        }
+                        else {
+                            // We've already processed this name so there's nothing more to do
+                        }
                     }
                     else {
                         Name nameObj = new Name(repository, name);
@@ -193,7 +209,12 @@ public class NamesDatabaseIntegrityCheck {
                                 newName = registeredName;
                             }
                             NameData newNameData = repository.getNameRepository().fromName(newName);
-                            if (!Objects.equals(creator.getAddress(), newNameData.getOwner())) {
+                            if (newNameData == null) {
+                                LOGGER.info("Error: registered name {} has no new name data. This is likely due to account {} " +
+                                                "being renamed another time, which is a scenario that is not yet checked automatically.",
+                                        updateNameTransactionData.getNewName(), creator.getAddress());
+                            }
+                            else 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;
@@ -313,6 +334,10 @@ public class NamesDatabaseIntegrityCheck {
                 transactions.add(transactionData);
             }
         }
+
+        // Sort by lowest timestamp first
+        transactions.sort(Comparator.comparingLong(TransactionData::getTimestamp));
+
         return transactions;
     }
 

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

@@ -239,6 +239,11 @@ public class TradeBot implements Listener {
 		if (!(event instanceof Synchronizer.NewChainTipEvent))
 			return;
 
+		// Don't process trade bots or broadcast presence timestamps if our chain is more than 30 minutes old
+		final Long minLatestBlockTimestamp = NTP.getTime() - (30 * 60 * 1000L);
+		if (!Controller.getInstance().isUpToDate(minLatestBlockTimestamp))
+			return;
+
 		synchronized (this) {
 			expireOldPresenceTimestamps();
 
@@ -397,7 +402,7 @@ public class TradeBot implements Listener {
 
 		long now = NTP.getTime();
 		long newExpiry = generateExpiry(now);
-		ByteArray pubkeyByteArray = ByteArray.of(tradeNativeAccount.getPublicKey());
+		ByteArray pubkeyByteArray = ByteArray.wrap(tradeNativeAccount.getPublicKey());
 
 		// If map entry's timestamp is missing, or within early renewal period, use the new expiry - otherwise use existing timestamp.
 		synchronized (this.ourTradePresenceTimestampsByPubkey) {
@@ -484,7 +489,7 @@ public class TradeBot implements Listener {
 		int knownCount = entriesUnknownToPeer.size();
 
 		for (TradePresenceData peersTradePresence : peersTradePresences) {
-			ByteArray pubkeyByteArray = ByteArray.of(peersTradePresence.getPublicKey());
+			ByteArray pubkeyByteArray = ByteArray.wrap(peersTradePresence.getPublicKey());
 
 			TradePresenceData ourEntry = entriesUnknownToPeer.get(pubkeyByteArray);
 
@@ -541,7 +546,7 @@ public class TradeBot implements Listener {
 					continue;
 				}
 
-				ByteArray pubkeyByteArray = ByteArray.of(peersTradePresence.getPublicKey());
+				ByteArray pubkeyByteArray = ByteArray.wrap(peersTradePresence.getPublicKey());
 
 				// Ignore if we've previously verified this timestamp+publickey combo or sent timestamp is older
 				TradePresenceData existingTradeData = this.safeAllTradePresencesByPubkey.get(pubkeyByteArray);
@@ -584,7 +589,7 @@ public class TradeBot implements Listener {
 					continue;
 				}
 
-				ByteArray atCodeHash = new ByteArray(atData.getCodeHash());
+				ByteArray atCodeHash = ByteArray.wrap(atData.getCodeHash());
 				Supplier<ACCT> acctSupplier = acctSuppliersByCodeHash.get(atCodeHash);
 				if (acctSupplier == null) {
 					LOGGER.trace("Ignoring trade presence {} from peer {} as AT isn't a known ACCT?",
@@ -637,7 +642,7 @@ public class TradeBot implements Listener {
 
 	public void bridgePresence(long timestamp, byte[] publicKey, byte[] signature, String atAddress) {
 		long expiry = generateExpiry(timestamp);
-		ByteArray pubkeyByteArray = ByteArray.of(publicKey);
+		ByteArray pubkeyByteArray = ByteArray.wrap(publicKey);
 
 		TradePresenceData fakeTradePresenceData = new TradePresenceData(expiry, publicKey, signature, atAddress);
 

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

@@ -42,30 +42,40 @@ public class Bitcoin extends Bitcoiny {
 			public Collection<ElectrumX.Server> getServers() {
 				return Arrays.asList(
 						// Servers chosen on NO BASIS WHATSOEVER from various sources!
-						new Server("hodlers.beer", 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),
+						// Status verified at https://1209k.com/bitcoin-eye/ele.php?chain=btc
+						//CLOSED new Server("bitcoin.grey.pw", Server.ConnectionType.SSL, 50002),
+						//CLOSED new Server("btc.litepay.ch", Server.ConnectionType.SSL, 50002),
+						//CLOSED new Server("electrum.pabu.io", Server.ConnectionType.SSL, 50002),
+						//CLOSED new Server("electrumx.hodlwallet.com", Server.ConnectionType.SSL, 50002),
+						//CLOSED new Server("gd42.org", Server.ConnectionType.SSL, 50002),
+						//CLOSED new Server("korea.electrum-server.com", Server.ConnectionType.SSL, 50002),
+						//CLOSED new Server("prospero.bitsrc.net", Server.ConnectionType.SSL, 50002),
+						//1.15.0 new Server("alviss.coinjoined.com", Server.ConnectionType.SSL, 50002),
+						//1.15.0 new Server("electrum.acinq.co", Server.ConnectionType.SSL, 50002),
+						//1.14.0 new Server("electrum.coinext.com.br", Server.ConnectionType.SSL, 50002),
+						new Server("104.248.139.211", Server.ConnectionType.SSL, 50002),
+						new Server("142.93.6.38", Server.ConnectionType.SSL, 50002),
+						new Server("157.245.172.236", Server.ConnectionType.SSL, 50002),
+						new Server("167.172.226.175", Server.ConnectionType.SSL, 50002),
+						new Server("167.172.42.31", Server.ConnectionType.SSL, 50002),
+						new Server("178.62.80.20", Server.ConnectionType.SSL, 50002),
 						new Server("185.64.116.15", Server.ConnectionType.SSL, 50002),
-						new Server("alviss.coinjoined.com", Server.ConnectionType.SSL, 50002),
-						new Server("btc.litepay.ch", Server.ConnectionType.SSL, 50002),
-						new Server("xtrum.com", Server.ConnectionType.SSL, 50002),
-						new Server("electrum.acinq.co", Server.ConnectionType.SSL, 50002),
-						new Server("caleb.vegas", Server.ConnectionType.SSL, 50002),
-						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("68.183.188.105", 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("blkhub.net", Server.ConnectionType.SSL, 50002),
+						new Server("btc.lastingcoin.net", Server.ConnectionType.SSL, 50002),
+						new Server("btce.iiiiiii.biz", Server.ConnectionType.SSL, 50002),
+						new Server("caleb.vegas", 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));
+						new Server("electrum.bitaroo.net", Server.ConnectionType.SSL, 50002),
+						new Server("electrumx.dev", Server.ConnectionType.SSL, 50002),
+						new Server("elx.bitske.com", Server.ConnectionType.SSL, 50002),
+						new Server("fortress.qtornado.com", Server.ConnectionType.SSL, 50002),
+						new Server("guichet.centure.cc", Server.ConnectionType.SSL, 50002),
+						new Server("kareoke.qoppa.org", Server.ConnectionType.SSL, 50002),
+						new Server("hodlers.beer", Server.ConnectionType.SSL, 50002),
+						new Server("node1.btccuracao.com", Server.ConnectionType.SSL, 50002),
+						new Server("xtrum.com", Server.ConnectionType.SSL, 50002));
 			}
 
 			@Override

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

@@ -45,9 +45,9 @@ public class Dogecoin extends Bitcoiny {
 			public Collection<Server> getServers() {
 				return Arrays.asList(
 						// Servers chosen on NO BASIS WHATSOEVER from various sources!
-						new Server("electrum1.cipig.net", ConnectionType.TCP, 10060),
-						new Server("electrum2.cipig.net", ConnectionType.TCP, 10060),
-						new Server("electrum3.cipig.net", ConnectionType.TCP, 10060));
+						new Server("electrum1.cipig.net", ConnectionType.SSL, 20060),
+						new Server("electrum2.cipig.net", ConnectionType.SSL, 20060),
+						new Server("electrum3.cipig.net", ConnectionType.SSL, 20060));
 						// TODO: add more mainnet servers. It's too centralized.
 			}
 

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

@@ -44,23 +44,17 @@ public class Litecoin extends Bitcoiny {
 			public Collection<ElectrumX.Server> getServers() {
 				return Arrays.asList(
 						// Servers chosen on NO BASIS WHATSOEVER from various sources!
-						new Server("electrum-ltc.someguy123.net", Server.ConnectionType.SSL, 50002),
-						new Server("backup.electrum-ltc.org", Server.ConnectionType.TCP, 50001),
+						// Status verified at https://1209k.com/bitcoin-eye/ele.php?chain=ltc
+						//CLOSED new Server("electrum-ltc.petrkr.net", Server.ConnectionType.SSL, 60002),
+						//CLOSED new Server("electrum-ltc.someguy123.net", Server.ConnectionType.SSL, 50002),
+						//PHISHY new Server("electrum-ltc.bysh.me", Server.ConnectionType.SSL, 50002),
 						new Server("backup.electrum-ltc.org", Server.ConnectionType.SSL, 443),
-						new Server("electrum.ltc.xurious.com", Server.ConnectionType.TCP, 50001),
 						new Server("electrum.ltc.xurious.com", Server.ConnectionType.SSL, 50002),
-						new Server("electrum-ltc.bysh.me", Server.ConnectionType.SSL, 50002),
+						new Server("electrum1.cipig.net", Server.ConnectionType.SSL, 20063),
 						new Server("electrum2.cipig.net", Server.ConnectionType.SSL, 20063),
 						new Server("electrum3.cipig.net", Server.ConnectionType.SSL, 20063),
-						new Server("electrum3.cipig.net", ConnectionType.TCP, 10063),
-						new Server("electrum2.cipig.net", Server.ConnectionType.TCP, 10063),
-						new Server("electrum1.cipig.net", Server.ConnectionType.SSL, 20063),
-						new Server("electrum1.cipig.net", Server.ConnectionType.TCP, 10063),
-						new Server("electrum-ltc.petrkr.net", Server.ConnectionType.SSL, 60002),
 						new Server("ltc.litepay.ch", Server.ConnectionType.SSL, 50022),
-						new Server("electrum-ltc-bysh.me", Server.ConnectionType.TCP, 50002),
-						new Server("electrum.jochen-hoenicke.de", Server.ConnectionType.TCP, 50005),
-						new Server("node.ispol.sk", Server.ConnectionType.TCP, 50004));
+						new Server("ltc.rentonrisk.com", Server.ConnectionType.SSL, 50002));
 			}
 
 			@Override

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

@@ -62,7 +62,7 @@ public enum SupportedBlockchain {
 	private static final Map<ByteArray, Supplier<ACCT>> supportedAcctsByCodeHash = Arrays.stream(SupportedBlockchain.values())
 			.map(supportedBlockchain -> supportedBlockchain.supportedAccts)
 			.flatMap(List::stream)
-			.collect(Collectors.toUnmodifiableMap(triple -> new ByteArray(triple.getB()), Triple::getC));
+			.collect(Collectors.toUnmodifiableMap(triple -> ByteArray.wrap(triple.getB()), Triple::getC));
 
 	private static final Map<String, Supplier<ACCT>> supportedAcctsByName = Arrays.stream(SupportedBlockchain.values())
 			.map(supportedBlockchain -> supportedBlockchain.supportedAccts)
@@ -94,7 +94,7 @@ public enum SupportedBlockchain {
 			return getAcctMap();
 
 		return blockchain.supportedAccts.stream()
-				.collect(Collectors.toUnmodifiableMap(triple -> new ByteArray(triple.getB()), Triple::getC));
+				.collect(Collectors.toUnmodifiableMap(triple -> ByteArray.wrap(triple.getB()), Triple::getC));
 	}
 
 	public static Map<ByteArray, Supplier<ACCT>> getFilteredAcctMap(String specificBlockchain) {
@@ -109,7 +109,7 @@ public enum SupportedBlockchain {
 	}
 
 	public static ACCT getAcctByCodeHash(byte[] codeHash) {
-		ByteArray wrappedCodeHash = new ByteArray(codeHash);
+		ByteArray wrappedCodeHash = ByteArray.wrap(codeHash);
 
 		Supplier<ACCT> acctInstanceSupplier = supportedAcctsByCodeHash.get(wrappedCodeHash);
 

src/main/java/org/qortal/data/group/GroupData.java

@@ -23,6 +23,7 @@ public class GroupData {
 	private ApprovalThreshold approvalThreshold;
 	private int minimumBlockDelay;
 	private int maximumBlockDelay;
+	public int memberCount;
 
 	/** Reference to CREATE_GROUP or UPDATE_GROUP transaction, used to rebuild group during orphaning. */
 	// No need to ever expose this via API

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

@@ -48,6 +48,7 @@ public class UpdateNameTransactionData extends TransactionData {
 
 	public void afterUnmarshal(Unmarshaller u, Object parent) {
 		this.creatorPublicKey = this.ownerPublicKey;
+		this.reducedNewName = this.newName != null ? Unicode.sanitize(this.newName) : null;
 	}
 
 	/** From repository */
@@ -62,7 +63,7 @@ public class UpdateNameTransactionData extends TransactionData {
 		this.nameReference = nameReference;
 	}
 
-	/** From network/API */
+	/** From network */
 	public UpdateNameTransactionData(BaseTransactionData baseTransactionData, String name, String newName, String newData) {
 		this(baseTransactionData, name, newName, newData, Unicode.sanitize(newName), null);
 	}

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

@@ -4,6 +4,7 @@ import java.awt.GraphicsEnvironment;
 import java.awt.image.BufferedImage;
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.ServiceConfigurationError;
 
 import javax.imageio.ImageIO;
 import javax.swing.JOptionPane;
@@ -49,7 +50,7 @@ public class Gui {
 	protected static BufferedImage loadImage(String resourceName) {
 		try (InputStream in = Gui.class.getResourceAsStream("/images/" + resourceName)) {
 			return ImageIO.read(in);
-		} catch (IllegalArgumentException | IOException e) {
+		} catch (IllegalArgumentException | IOException | ServiceConfigurationError e) {
 			LOGGER.warn(String.format("Couldn't locate image resource \"images/%s\"", resourceName));
 			return null;
 		}

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

@@ -13,7 +13,7 @@ import org.qortal.crypto.MemoryPoW;
 import org.qortal.network.message.ChallengeMessage;
 import org.qortal.network.message.HelloMessage;
 import org.qortal.network.message.Message;
-import org.qortal.network.message.Message.MessageType;
+import org.qortal.network.message.MessageType;
 import org.qortal.settings.Settings;
 import org.qortal.network.message.ResponseMessage;
 import org.qortal.utils.DaemonThreadFactory;

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

@@ -8,11 +8,13 @@ import org.bouncycastle.crypto.params.Ed25519PublicKeyParameters;
 import org.qortal.block.BlockChain;
 import org.qortal.controller.Controller;
 import org.qortal.controller.arbitrary.ArbitraryDataFileListManager;
+import org.qortal.controller.arbitrary.ArbitraryDataManager;
 import org.qortal.crypto.Crypto;
 import org.qortal.data.block.BlockData;
 import org.qortal.data.network.PeerData;
 import org.qortal.data.transaction.TransactionData;
 import org.qortal.network.message.*;
+import org.qortal.network.task.*;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
 import org.qortal.repository.RepositoryManager;
@@ -32,6 +34,7 @@ import java.nio.channels.*;
 import java.security.SecureRandom;
 import java.util.*;
 import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.Function;
@@ -41,9 +44,8 @@ import java.util.stream.Collectors;
 // For managing peers
 public class Network {
     private static final Logger LOGGER = LogManager.getLogger(Network.class);
-    private static Network instance;
 
-    private static final int LISTEN_BACKLOG = 10;
+    private static final int LISTEN_BACKLOG = 5;
     /**
      * How long before retrying after a connection failure, in milliseconds.
      */
@@ -122,14 +124,8 @@ public class Network {
     private final ExecuteProduceConsume networkEPC;
     private Selector channelSelector;
     private ServerSocketChannel serverChannel;
-    private Iterator<SelectionKey> channelIterator = null;
-
-    // volatile because value is updated inside any one of the EPC threads
-    private volatile long nextConnectTaskTimestamp = 0L; // ms - try first connect once NTP syncs
-
-    private final ExecutorService broadcastExecutor = Executors.newCachedThreadPool();
-    // volatile because value is updated inside any one of the EPC threads
-    private volatile long nextBroadcastTimestamp = 0L; // ms - try first broadcast once NTP syncs
+    private SelectionKey serverSelectionKey;
+    private final Set<SelectableChannel> channelsPendingWrite = ConcurrentHashMap.newKeySet();
 
     private final Lock mergePeersLock = new ReentrantLock();
 
@@ -137,6 +133,8 @@ public class Network {
     private String ourExternalIpAddress = null;
     private int ourExternalPort = Settings.getInstance().getListenPort();
 
+    private volatile boolean isShuttingDown = false;
+
     // Constructors
 
     private Network() {
@@ -170,7 +168,7 @@ public class Network {
             serverChannel.configureBlocking(false);
             serverChannel.setOption(StandardSocketOptions.SO_REUSEADDR, true);
             serverChannel.bind(endpoint, LISTEN_BACKLOG);
-            serverChannel.register(channelSelector, SelectionKey.OP_ACCEPT);
+            serverSelectionKey = serverChannel.register(channelSelector, SelectionKey.OP_ACCEPT);
         } catch (UnknownHostException e) {
             LOGGER.error("Can't bind listen socket to address {}", Settings.getInstance().getBindAddress());
             throw new IOException("Can't bind listen socket to address", e);
@@ -180,7 +178,8 @@ public class Network {
         }
 
         // Load all known peers from repository
-        synchronized (this.allKnownPeers) { List<String> fixedNetwork = Settings.getInstance().getFixedNetwork();
+        synchronized (this.allKnownPeers) {
+            List<String> fixedNetwork = Settings.getInstance().getFixedNetwork();
             if (fixedNetwork != null && !fixedNetwork.isEmpty()) {
                 Long addedWhen = NTP.getTime();
                 String addedBy = "fixedNetwork";
@@ -214,12 +213,16 @@ public class Network {
 
     // Getters / setters
 
-    public static synchronized Network getInstance() {
-        if (instance == null) {
-            instance = new Network();
-        }
+    private static class SingletonContainer {
+        private static final Network INSTANCE = new Network();
+    }
 
-        return instance;
+    public static Network getInstance() {
+        return SingletonContainer.INSTANCE;
+    }
+
+    public int getMaxPeers() {
+        return this.maxPeers;
     }
 
     public byte[] getMessageMagic() {
@@ -257,6 +260,18 @@ public class Network {
         return this.immutableConnectedPeers;
     }
 
+    public List<Peer> getImmutableConnectedDataPeers() {
+        return this.getImmutableConnectedPeers().stream()
+                .filter(p -> p.isDataPeer())
+                .collect(Collectors.toList());
+    }
+
+    public List<Peer> getImmutableConnectedNonDataPeers() {
+        return this.getImmutableConnectedPeers().stream()
+                .filter(p -> !p.isDataPeer())
+                .collect(Collectors.toList());
+    }
+
     public void addConnectedPeer(Peer peer) {
         this.connectedPeers.add(peer); // thread safe thanks to synchronized list
         this.immutableConnectedPeers = List.copyOf(this.connectedPeers); // also thread safe thanks to synchronized collection's toArray() being fed to List.of(array)
@@ -323,6 +338,7 @@ public class Network {
                         // Add this signature to the list of pending requests for this peer
                         LOGGER.info("Making connection to peer {} to request files for signature {}...", peerAddressString, Base58.encode(signature));
                         Peer peer = new Peer(peerData);
+                        peer.setIsDataPeer(true);
                         peer.addPendingSignatureRequest(signature);
                         return this.connectPeer(peer);
                         // If connection (and handshake) is successful, data will automatically be requested
@@ -453,6 +469,11 @@ public class Network {
 
     class NetworkProcessor extends ExecuteProduceConsume {
 
+        private final AtomicLong nextConnectTaskTimestamp = new AtomicLong(0L); // ms - try first connect once NTP syncs
+        private final AtomicLong nextBroadcastTimestamp = new AtomicLong(0L); // ms - try first broadcast once NTP syncs
+
+        private Iterator<SelectionKey> channelIterator = null;
+
         NetworkProcessor(ExecutorService executor) {
             super(executor);
         }
@@ -494,43 +515,23 @@ public class Network {
         }
 
         private Task maybeProducePeerMessageTask() {
-            for (Peer peer : getImmutableConnectedPeers()) {
-                Task peerTask = peer.getMessageTask();
-                if (peerTask != null) {
-                    return peerTask;
-                }
-            }
-
-            return null;
+            return getImmutableConnectedPeers().stream()
+                    .map(Peer::getMessageTask)
+                    .filter(Objects::nonNull)
+                    .findFirst()
+                    .orElse(null);
         }
 
         private Task maybeProducePeerPingTask(Long now) {
-            // Ask connected peers whether they need a ping
-            for (Peer peer : getImmutableHandshakedPeers()) {
-                Task peerTask = peer.getPingTask(now);
-                if (peerTask != null) {
-                    return peerTask;
-                }
-            }
-
-            return null;
-        }
-
-        class PeerConnectTask implements ExecuteProduceConsume.Task {
-            private final Peer peer;
-
-            PeerConnectTask(Peer peer) {
-                this.peer = peer;
-            }
-
-            @Override
-            public void perform() throws InterruptedException {
-                connectPeer(peer);
-            }
+            return getImmutableHandshakedPeers().stream()
+                    .map(peer -> peer.getPingTask(now))
+                    .filter(Objects::nonNull)
+                    .findFirst()
+                    .orElse(null);
         }
 
         private Task maybeProduceConnectPeerTask(Long now) throws InterruptedException {
-            if (now == null || now < nextConnectTaskTimestamp) {
+            if (now == null || now < nextConnectTaskTimestamp.get()) {
                 return null;
             }
 
@@ -538,7 +539,7 @@ public class Network {
                 return null;
             }
 
-            nextConnectTaskTimestamp = now + 1000L;
+            nextConnectTaskTimestamp.set(now + 1000L);
 
             Peer targetPeer = getConnectablePeer(now);
             if (targetPeer == null) {
@@ -550,66 +551,15 @@ public class Network {
         }
 
         private Task maybeProduceBroadcastTask(Long now) {
-            if (now == null || now < nextBroadcastTimestamp) {
+            if (now == null || now < nextBroadcastTimestamp.get()) {
                 return null;
             }
 
-            nextBroadcastTimestamp = now + BROADCAST_INTERVAL;
-            return () -> Controller.getInstance().doNetworkBroadcast();
-        }
-
-        class ChannelTask implements ExecuteProduceConsume.Task {
-            private final SelectionKey selectionKey;
-
-            ChannelTask(SelectionKey selectionKey) {
-                this.selectionKey = selectionKey;
-            }
-
-            @Override
-            public void perform() throws InterruptedException {
-                try {
-                    LOGGER.trace("Thread {} has pending channel: {}, with ops {}",
-                            Thread.currentThread().getId(), selectionKey.channel(), selectionKey.readyOps());
-
-                    // process pending channel task
-                    if (selectionKey.isReadable()) {
-                        connectionRead((SocketChannel) selectionKey.channel());
-                    } else if (selectionKey.isAcceptable()) {
-                        acceptConnection((ServerSocketChannel) selectionKey.channel());
-                    }
-
-                    LOGGER.trace("Thread {} processed channel: {}",
-                            Thread.currentThread().getId(), selectionKey.channel());
-                } catch (CancelledKeyException e) {
-                    LOGGER.trace("Thread {} encountered cancelled channel: {}",
-                            Thread.currentThread().getId(), selectionKey.channel());
-                }
-            }
-
-            private void connectionRead(SocketChannel socketChannel) {
-                Peer peer = getPeerFromChannel(socketChannel);
-                if (peer == null) {
-                    return;
-                }
-
-                try {
-                    peer.readChannel();
-                } catch (IOException e) {
-                    if (e.getMessage() != null && e.getMessage().toLowerCase().contains("connection reset")) {
-                        peer.disconnect("Connection reset");
-                        return;
-                    }
-
-                    LOGGER.trace("[{}] Network thread {} encountered I/O error: {}", peer.getPeerConnectionId(),
-                            Thread.currentThread().getId(), e.getMessage(), e);
-                    peer.disconnect("I/O error");
-                }
-            }
+            nextBroadcastTimestamp.set(now + BROADCAST_INTERVAL);
+            return new BroadcastTask();
         }
 
         private Task maybeProduceChannelTask(boolean canBlock) throws InterruptedException {
-            final SelectionKey nextSelectionKey;
-
             // Synchronization here to enforce thread-safety on channelIterator
             synchronized (channelSelector) {
                 // anything to do?
@@ -630,91 +580,73 @@ public class Network {
                     }
 
                     channelIterator = channelSelector.selectedKeys().iterator();
+                    LOGGER.trace("Thread {}, after {} select, channelIterator now {}",
+                            Thread.currentThread().getId(),
+                            canBlock ? "blocking": "non-blocking",
+                            channelIterator);
                 }
 
-                if (channelIterator.hasNext()) {
-                    nextSelectionKey = channelIterator.next();
-                    channelIterator.remove();
-                } else {
-                    nextSelectionKey = null;
+                if (!channelIterator.hasNext()) {
                     channelIterator = null; // Nothing to do so reset iterator to cause new select
+
+                    LOGGER.trace("Thread {}, channelIterator now null", Thread.currentThread().getId());
+                    return null;
                 }
 
-                LOGGER.trace("Thread {}, nextSelectionKey {}, channelIterator now {}",
-                        Thread.currentThread().getId(), nextSelectionKey, channelIterator);
-            }
+                final SelectionKey nextSelectionKey = channelIterator.next();
+                channelIterator.remove();
 
-            if (nextSelectionKey == null) {
-                return null;
-            }
+                // Just in case underlying socket channel already closed elsewhere, etc.
+                if (!nextSelectionKey.isValid())
+                    return null;
 
-            return new ChannelTask(nextSelectionKey);
-        }
-    }
+                LOGGER.trace("Thread {}, nextSelectionKey {}", Thread.currentThread().getId(), nextSelectionKey);
 
-    private void acceptConnection(ServerSocketChannel serverSocketChannel) throws InterruptedException {
-        SocketChannel socketChannel;
+                SelectableChannel socketChannel = nextSelectionKey.channel();
 
-        try {
-            socketChannel = serverSocketChannel.accept();
-        } catch (IOException e) {
-            return;
-        }
-
-        // No connection actually accepted?
-        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", address);
-                socketChannel.close();
-                return;
-            }
-
-            if (getImmutableConnectedPeers().size() >= maxPeers) {
-                // We have enough peers
-                LOGGER.debug("Connection discarded from peer {} because the server is full", address);
-                socketChannel.close();
-                return;
-            }
-
-            LOGGER.debug("Connection accepted from peer {}", address);
-
-            newPeer = new Peer(socketChannel, channelSelector);
-            this.addConnectedPeer(newPeer);
-
-        } 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?
+                    if (nextSelectionKey.isReadable()) {
+                        clearInterestOps(nextSelectionKey, SelectionKey.OP_READ);
+                        Peer peer = getPeerFromChannel((SocketChannel) socketChannel);
+                        if (peer == null)
+                            return null;
+
+                        return new ChannelReadTask((SocketChannel) socketChannel, peer);
+                    }
+
+                    if (nextSelectionKey.isWritable()) {
+                        clearInterestOps(nextSelectionKey, SelectionKey.OP_WRITE);
+                        Peer peer = getPeerFromChannel((SocketChannel) socketChannel);
+                        if (peer == null)
+                            return null;
+
+                        // Any thread that queues a message to send can set OP_WRITE,
+                        // but we only allow one pending/active ChannelWriteTask per Peer
+                        if (!channelsPendingWrite.add(socketChannel))
+                            return null;
+
+                        return new ChannelWriteTask((SocketChannel) socketChannel, peer);
+                    }
+
+                    if (nextSelectionKey.isAcceptable()) {
+                        clearInterestOps(nextSelectionKey, SelectionKey.OP_ACCEPT);
+                        return new ChannelAcceptTask((ServerSocketChannel) socketChannel);
+                    }
+                } catch (CancelledKeyException e) {
+                    /*
+                     * Sometimes nextSelectionKey is cancelled / becomes invalid between the isValid() test at line 586
+                     * and later calls to isReadable() / isWritable() / isAcceptable() which themselves call isValid()!
+                     * Those isXXXable() calls could throw CancelledKeyException, so we catch it here and return null.
+                     */
+                    return null;
                 }
             }
-            return;
-        }
 
-        this.onPeerReady(newPeer);
+            return null;
+        }
     }
 
-    private boolean ipNotInFixedList(PeerAddress address, List<String> fixedNetwork) {
+    public 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])) {
@@ -750,8 +682,9 @@ public class Network {
             peers.removeIf(isConnectedPeer);
 
             // Don't consider already connected peers (resolved address match)
-            // XXX This might be too slow if we end up waiting a long time for hostnames to resolve via DNS
-            peers.removeIf(isResolvedAsConnectedPeer);
+            // Disabled because this might be too slow if we end up waiting a long time for hostnames to resolve via DNS
+            // Which is ok because duplicate connections to the same peer are handled during handshaking
+            // peers.removeIf(isResolvedAsConnectedPeer);
 
             this.checkLongestConnection(now);
 
@@ -766,6 +699,7 @@ public class Network {
             // Pick candidate
             PeerData peerData = peers.get(peerIndex);
             Peer newPeer = new Peer(peerData);
+            newPeer.setIsDataPeer(false);
 
             // Update connection attempt info
             peerData.setLastAttempted(now);
@@ -781,8 +715,12 @@ public class Network {
         }
     }
 
-    private boolean connectPeer(Peer newPeer) throws InterruptedException {
-        SocketChannel socketChannel = newPeer.connect(this.channelSelector);
+    public boolean connectPeer(Peer newPeer) throws InterruptedException {
+        // Also checked before creating PeerConnectTask
+        if (getImmutableOutboundHandshakedPeers().size() >= minOutboundPeers)
+            return false;
+
+        SocketChannel socketChannel = newPeer.connect();
         if (socketChannel == null) {
             return false;
         }
@@ -797,7 +735,7 @@ public class Network {
         return true;
     }
 
-    private Peer getPeerFromChannel(SocketChannel socketChannel) {
+    public Peer getPeerFromChannel(SocketChannel socketChannel) {
         for (Peer peer : this.getImmutableConnectedPeers()) {
             if (peer.getSocketChannel() == socketChannel) {
                 return peer;
@@ -830,7 +768,74 @@ public class Network {
         nextDisconnectionCheck = now + DISCONNECTION_CHECK_INTERVAL;
     }
 
-    // Peer callbacks
+    // SocketChannel interest-ops manipulations
+
+    private static final String[] OP_NAMES = new String[SelectionKey.OP_ACCEPT * 2];
+    static {
+        for (int i = 0; i < OP_NAMES.length; i++) {
+            StringJoiner joiner = new StringJoiner(",");
+
+            if ((i & SelectionKey.OP_READ) != 0) joiner.add("OP_READ");
+            if ((i & SelectionKey.OP_WRITE) != 0) joiner.add("OP_WRITE");
+            if ((i & SelectionKey.OP_CONNECT) != 0) joiner.add("OP_CONNECT");
+            if ((i & SelectionKey.OP_ACCEPT) != 0) joiner.add("OP_ACCEPT");
+
+            OP_NAMES[i] = joiner.toString();
+        }
+    }
+
+    public void clearInterestOps(SelectableChannel socketChannel, int interestOps) {
+        SelectionKey selectionKey = socketChannel.keyFor(channelSelector);
+        if (selectionKey == null)
+            return;
+
+        clearInterestOps(selectionKey, interestOps);
+    }
+
+    private void clearInterestOps(SelectionKey selectionKey, int interestOps) {
+        if (!selectionKey.channel().isOpen())
+            return;
+
+        LOGGER.trace("Thread {} clearing {} interest-ops on channel: {}",
+                Thread.currentThread().getId(),
+                OP_NAMES[interestOps],
+                selectionKey.channel());
+
+        selectionKey.interestOpsAnd(~interestOps);
+    }
+
+    public void setInterestOps(SelectableChannel socketChannel, int interestOps) {
+        SelectionKey selectionKey = socketChannel.keyFor(channelSelector);
+        if (selectionKey == null) {
+            try {
+                selectionKey = socketChannel.register(this.channelSelector, interestOps);
+            } catch (ClosedChannelException e) {
+                // Channel already closed so ignore
+                return;
+            }
+            // Fall-through to allow logging
+        }
+
+        setInterestOps(selectionKey, interestOps);
+    }
+
+    private void setInterestOps(SelectionKey selectionKey, int interestOps) {
+        if (!selectionKey.channel().isOpen())
+            return;
+
+        LOGGER.trace("Thread {} setting {} interest-ops on channel: {}",
+                Thread.currentThread().getId(),
+                OP_NAMES[interestOps],
+                selectionKey.channel());
+
+        selectionKey.interestOpsOr(interestOps);
+    }
+
+    // Peer / Task callbacks
+
+    public void notifyChannelNotWriting(SelectableChannel socketChannel) {
+        this.channelsPendingWrite.remove(socketChannel);
+    }
 
     protected void wakeupChannelSelector() {
         this.channelSelector.wakeup();
@@ -856,8 +861,6 @@ public class Network {
     }
 
     public void onDisconnect(Peer peer) {
-        // Notify Controller
-        Controller.getInstance().onPeerDisconnect(peer);
         if (peer.getConnectionEstablishedTime() > 0L) {
             LOGGER.debug("[{}] Disconnected from peer {}", peer.getPeerConnectionId(), peer);
         } else {
@@ -865,6 +868,25 @@ public class Network {
         }
 
         this.removeConnectedPeer(peer);
+        this.channelsPendingWrite.remove(peer.getSocketChannel());
+
+        if (this.isShuttingDown)
+            // No need to do any further processing, like re-enabling listen socket or notifying Controller
+            return;
+
+        if (getImmutableConnectedPeers().size() < maxPeers - 1
+                && serverSelectionKey.isValid()
+                && (serverSelectionKey.interestOps() & SelectionKey.OP_ACCEPT) == 0) {
+            try {
+                LOGGER.debug("Re-enabling accepting incoming connections because the server is not longer full");
+                setInterestOps(serverSelectionKey, SelectionKey.OP_ACCEPT);
+            } catch (CancelledKeyException e) {
+                LOGGER.error("Failed to re-enable accepting of incoming connections: {}", e.getMessage());
+            }
+        }
+
+        // Notify Controller
+        Controller.getInstance().onPeerDisconnect(peer);
     }
 
     public void peerMisbehaved(Peer peer) {
@@ -1302,8 +1324,9 @@ public class Network {
         try {
             InetSocketAddress knownAddress = peerAddress.toSocketAddress();
 
-            List<Peer> peers = this.getImmutableConnectedPeers();
-            peers.removeIf(peer -> !Peer.addressEquals(knownAddress, peer.getResolvedAddress()));
+            List<Peer> peers = this.getImmutableConnectedPeers().stream()
+                    .filter(peer -> Peer.addressEquals(knownAddress, peer.getResolvedAddress()))
+                    .collect(Collectors.toList());
 
             for (Peer peer : peers) {
                 peer.disconnect("to be forgotten");
@@ -1461,54 +1484,27 @@ public class Network {
     }
 
     public void broadcast(Function<Peer, Message> peerMessageBuilder) {
-        class Broadcaster implements Runnable {
-            private final Random random = new Random();
+        for (Peer peer : getImmutableHandshakedPeers()) {
+            if (this.isShuttingDown)
+                return;
 
-            private List<Peer> targetPeers;
-            private Function<Peer, Message> peerMessageBuilder;
+            Message message = peerMessageBuilder.apply(peer);
 
-            Broadcaster(List<Peer> targetPeers, Function<Peer, Message> peerMessageBuilder) {
-                this.targetPeers = targetPeers;
-                this.peerMessageBuilder = peerMessageBuilder;
+            if (message == null) {
+                continue;
             }
 
-            @Override
-            public void run() {
-                Thread.currentThread().setName("Network Broadcast");
-
-                for (Peer peer : targetPeers) {
-                    // Very short sleep to reduce strain, improve multi-threading and catch interrupts
-                    try {
-                        Thread.sleep(random.nextInt(20) + 20L);
-                    } catch (InterruptedException e) {
-                        break;
-                    }
-
-                    Message message = peerMessageBuilder.apply(peer);
-
-                    if (message == null) {
-                        continue;
-                    }
-
-                    if (!peer.sendMessage(message)) {
-                        peer.disconnect("failed to broadcast message");
-                    }
-                }
-
-                Thread.currentThread().setName("Network Broadcast (dormant)");
+            if (!peer.sendMessage(message)) {
+                peer.disconnect("failed to broadcast message");
             }
         }
-
-        try {
-            broadcastExecutor.execute(new Broadcaster(this.getImmutableHandshakedPeers(), peerMessageBuilder));
-        } catch (RejectedExecutionException e) {
-            // Can't execute - probably because we're shutting down, so ignore
-        }
     }
 
     // Shutdown
 
     public void shutdown() {
+        this.isShuttingDown = true;
+
         // Close listen socket to prevent more incoming connections
         if (this.serverChannel.isOpen()) {
             try {
@@ -1527,16 +1523,6 @@ public class Network {
             LOGGER.warn("Interrupted while waiting for networking threads to terminate");
         }
 
-        // Stop broadcasts
-        this.broadcastExecutor.shutdownNow();
-        try {
-            if (!this.broadcastExecutor.awaitTermination(1000, TimeUnit.MILLISECONDS)) {
-                LOGGER.warn("Broadcast threads failed to terminate");
-            }
-        } catch (InterruptedException e) {
-            LOGGER.warn("Interrupted while waiting for broadcast threads failed to terminate");
-        }
-
         // Close all peer connections
         for (Peer peer : this.getImmutableConnectedPeers()) {
             peer.shutdown();

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

@@ -11,25 +11,21 @@ import org.qortal.data.network.PeerChainTipData;
 import org.qortal.data.network.PeerData;
 import org.qortal.network.message.ChallengeMessage;
 import org.qortal.network.message.Message;
-import org.qortal.network.message.Message.MessageException;
-import org.qortal.network.message.Message.MessageType;
-import org.qortal.network.message.PingMessage;
+import org.qortal.network.message.MessageException;
+import org.qortal.network.task.MessageTask;
+import org.qortal.network.task.PingTask;
 import org.qortal.settings.Settings;
-import org.qortal.utils.ExecuteProduceConsume;
+import org.qortal.utils.ExecuteProduceConsume.Task;
 import org.qortal.utils.NTP;
 
 import java.io.IOException;
 import java.net.*;
 import java.nio.ByteBuffer;
 import java.nio.channels.SelectionKey;
-import java.nio.channels.Selector;
 import java.nio.channels.SocketChannel;
 import java.security.SecureRandom;
 import java.util.*;
-import java.util.concurrent.ArrayBlockingQueue;
-import java.util.concurrent.BlockingQueue;
-import java.util.concurrent.LinkedBlockingQueue;
-import java.util.concurrent.TimeUnit;
+import java.util.concurrent.*;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -48,9 +44,9 @@ public class Peer {
     private static final int RESPONSE_TIMEOUT = 3000; // ms
 
     /**
-     * Maximum time to wait for a peer to respond with blocks (ms)
+     * Maximum time to wait for a message to be added to sendQueue (ms)
      */
-    public static final int FETCH_BLOCKS_TIMEOUT = 10000;
+    private static final int QUEUE_TIMEOUT = 1000; // ms
 
     /**
      * Interval between PING messages to a peer. (ms)
@@ -68,13 +64,22 @@ public class Peer {
      */
     private boolean isLocal;
 
+    /**
+     * True if connected for the purposes of transfering specific QDN data
+     */
+    private boolean isDataPeer;
+
     private final UUID peerConnectionId = UUID.randomUUID();
     private final Object byteBufferLock = new Object();
     private ByteBuffer byteBuffer;
-
     private Map<Integer, BlockingQueue<Message>> replyQueues;
     private LinkedBlockingQueue<Message> pendingMessages;
 
+    private TransferQueue<Message> sendQueue;
+    private ByteBuffer outputBuffer;
+    private String outputMessageType;
+    private int outputMessageId;
+
     /**
      * True if we created connection to peer, false if we accepted incoming connection from peer.
      */
@@ -98,7 +103,7 @@ public class Peer {
     /**
      * When last PING message was sent, or null if pings not started yet.
      */
-    private Long lastPingSent;
+    private Long lastPingSent = null;
 
     byte[] ourChallenge;
 
@@ -160,10 +165,10 @@ public class Peer {
     /**
      * Construct Peer using existing, connected socket
      */
-    public Peer(SocketChannel socketChannel, Selector channelSelector) throws IOException {
+    public Peer(SocketChannel socketChannel) throws IOException {
         this.isOutbound = false;
         this.socketChannel = socketChannel;
-        sharedSetup(channelSelector);
+        sharedSetup();
 
         this.resolvedAddress = ((InetSocketAddress) socketChannel.socket().getRemoteSocketAddress());
         this.isLocal = isAddressLocal(this.resolvedAddress.getAddress());
@@ -194,6 +199,14 @@ public class Peer {
         return this.isOutbound;
     }
 
+    public boolean isDataPeer() {
+        return isDataPeer;
+    }
+
+    public void setIsDataPeer(boolean isDataPeer) {
+        this.isDataPeer = isDataPeer;
+    }
+
     public Handshake getHandshakeStatus() {
         synchronized (this.handshakingLock) {
             return this.handshakeStatus;
@@ -211,6 +224,11 @@ public class Peer {
     }
 
     private void generateRandomMaxConnectionAge() {
+        if (this.maxConnectionAge > 0L) {
+            // Already generated, so we don't want to overwrite the existing value
+            return;
+        }
+
         // Retrieve the min and max connection time from the settings, and calculate the range
         final int minPeerConnectionTime = Settings.getInstance().getMinPeerConnectionTime();
         final int maxPeerConnectionTime = Settings.getInstance().getMaxPeerConnectionTime();
@@ -276,7 +294,7 @@ public class Peer {
         }
     }
 
-    protected void setLastPing(long lastPing) {
+    public void setLastPing(long lastPing) {
         synchronized (this.peerInfoLock) {
             this.lastPing = lastPing;
         }
@@ -346,12 +364,6 @@ public class Peer {
         }
     }
 
-    protected void queueMessage(Message message) {
-        if (!this.pendingMessages.offer(message)) {
-            LOGGER.info("[{}] No room to queue message from peer {} - discarding", this.peerConnectionId, this);
-        }
-    }
-
     public boolean isSyncInProgress() {
         return this.syncInProgress;
     }
@@ -396,13 +408,14 @@ public class Peer {
 
     // Processing
 
-    private void sharedSetup(Selector channelSelector) throws IOException {
+    private void sharedSetup() throws IOException {
         this.connectionTimestamp = NTP.getTime();
         this.socketChannel.setOption(StandardSocketOptions.TCP_NODELAY, true);
         this.socketChannel.configureBlocking(false);
-        this.socketChannel.register(channelSelector, SelectionKey.OP_READ);
+        Network.getInstance().setInterestOps(this.socketChannel, SelectionKey.OP_READ);
         this.byteBuffer = null; // Defer allocation to when we need it, to save memory. Sorry GC!
-        this.replyQueues = Collections.synchronizedMap(new HashMap<Integer, BlockingQueue<Message>>());
+        this.sendQueue = new LinkedTransferQueue<>();
+        this.replyQueues = new ConcurrentHashMap<>();
         this.pendingMessages = new LinkedBlockingQueue<>();
 
         Random random = new SecureRandom();
@@ -410,7 +423,7 @@ public class Peer {
         random.nextBytes(this.ourChallenge);
     }
 
-    public SocketChannel connect(Selector channelSelector) {
+    public SocketChannel connect() {
         LOGGER.trace("[{}] Connecting to peer {}", this.peerConnectionId, this);
 
         try {
@@ -418,6 +431,8 @@ public class Peer {
             this.isLocal = isAddressLocal(this.resolvedAddress.getAddress());
 
             this.socketChannel = SocketChannel.open();
+            InetAddress bindAddr = InetAddress.getByName(Settings.getInstance().getBindAddress());
+            this.socketChannel.socket().bind(new InetSocketAddress(bindAddr, 0));
             this.socketChannel.socket().connect(resolvedAddress, CONNECT_TIMEOUT);
         } catch (SocketTimeoutException e) {
             LOGGER.trace("[{}] Connection timed out to peer {}", this.peerConnectionId, this);
@@ -432,7 +447,7 @@ public class Peer {
 
         try {
             LOGGER.debug("[{}] Connected to peer {}", this.peerConnectionId, this);
-            sharedSetup(channelSelector);
+            sharedSetup();
             return socketChannel;
         } catch (IOException e) {
             LOGGER.trace("[{}] Post-connection setup failed, peer {}", this.peerConnectionId, this);
@@ -450,7 +465,7 @@ public class Peer {
      *
      * @throws IOException If this channel is not yet connected
      */
-    protected void readChannel() throws IOException {
+    public void readChannel() throws IOException {
         synchronized (this.byteBufferLock) {
             while (true) {
                 if (!this.socketChannel.isOpen() || this.socketChannel.socket().isClosed()) {
@@ -556,7 +571,67 @@ public class Peer {
         }
     }
 
-    protected ExecuteProduceConsume.Task getMessageTask() {
+    /** Maybe send some pending outgoing messages.
+     *
+     * @return true if more data is pending to be sent
+     */
+    public boolean writeChannel() throws IOException {
+        // It is the responsibility of ChannelWriteTask's producer to produce only one call to writeChannel() at a time
+
+        while (true) {
+            // If output byte buffer is null, fetch next message from queue (if any)
+            while (this.outputBuffer == null) {
+                Message message;
+
+                try {
+                    // Allow other thread time to add message to queue having raised OP_WRITE.
+                    // Timeout is overkill but not excessive enough to clog up networking / EPC.
+                    // This is to avoid race condition in sendMessageWithTimeout() below.
+                    message = this.sendQueue.poll(QUEUE_TIMEOUT, TimeUnit.MILLISECONDS);
+                } catch (InterruptedException e) {
+                    // Shutdown situation
+                    return false;
+                }
+
+                // No message? No further work to be done
+                if (message == null)
+                    return false;
+
+                try {
+                    this.outputBuffer = ByteBuffer.wrap(message.toBytes());
+                    this.outputMessageType = message.getType().name();
+                    this.outputMessageId = message.getId();
+
+                    LOGGER.trace("[{}] Sending {} message with ID {} to peer {}",
+                            this.peerConnectionId, this.outputMessageType, this.outputMessageId, this);
+                } catch (MessageException e) {
+                    // Something went wrong converting message to bytes, so discard but allow another round
+                    LOGGER.warn("[{}] Failed to send {} message with ID {} to peer {}: {}", this.peerConnectionId,
+                            message.getType().name(), message.getId(), this, e.getMessage());
+                }
+            }
+
+            // If output byte buffer is not null, send from that
+            int bytesWritten = this.socketChannel.write(outputBuffer);
+
+            LOGGER.trace("[{}] Sent {} bytes of {} message with ID {} to peer {} ({} total)", this.peerConnectionId,
+                    bytesWritten, this.outputMessageType, this.outputMessageId, this, outputBuffer.limit());
+
+            // If we've sent 0 bytes then socket buffer is full so we need to wait until it's empty again
+            if (bytesWritten == 0) {
+                return true;
+            }
+
+            // If we then exhaust the byte buffer, set it to null (otherwise loop and try to send more)
+            if (!this.outputBuffer.hasRemaining()) {
+                this.outputMessageType = null;
+                this.outputMessageId = 0;
+                this.outputBuffer = null;
+            }
+        }
+    }
+
+    protected Task getMessageTask() {
         /*
          * If we are still handshaking and there is a message yet to be processed then
          * don't produce another message task. This allows us to process handshake
@@ -580,7 +655,7 @@ public class Peer {
         }
 
         // Return a task to process message in queue
-        return () -> Network.getInstance().onMessage(this, nextMessage);
+        return new MessageTask(this, nextMessage);
     }
 
     /**
@@ -605,54 +680,25 @@ public class Peer {
         }
 
         try {
-            // Send message
-            LOGGER.trace("[{}] Sending {} message with ID {} to peer {}", this.peerConnectionId,
+            // Queue message, to be picked up by ChannelWriteTask and then peer.writeChannel()
+            LOGGER.trace("[{}] Queuing {} message with ID {} to peer {}", this.peerConnectionId,
                     message.getType().name(), message.getId(), this);
 
-            ByteBuffer outputBuffer = ByteBuffer.wrap(message.toBytes());
+            // Check message properly constructed
+            message.checkValidOutgoing();
 
-            synchronized (this.socketChannel) {
-                final long sendStart = System.currentTimeMillis();
-                long totalBytes = 0;
-
-                while (outputBuffer.hasRemaining()) {
-                    int bytesWritten = this.socketChannel.write(outputBuffer);
-                    totalBytes += bytesWritten;
-
-                    LOGGER.trace("[{}] Sent {} bytes of {} message with ID {} to peer {} ({} total)", this.peerConnectionId,
-                            bytesWritten, message.getType().name(), message.getId(), this, totalBytes);
-
-                    if (bytesWritten == 0) {
-                        // Underlying socket's internal buffer probably full,
-                        // so wait a short while for bytes to actually be transmitted over the wire
-
-                        /*
-                         * NOSONAR squid:S2276 - we don't want to use this.socketChannel.wait()
-                         * as this releases the lock held by synchronized() above
-                         * and would allow another thread to send another message,
-                         * potentially interleaving them on-the-wire, causing checksum failures
-                         * and connection loss.
-                         */
-                        Thread.sleep(1L); //NOSONAR squid:S2276
-
-                        if (System.currentTimeMillis() - sendStart > timeout) {
-                            // We've taken too long to send this message
-                            return false;
-                        }
-                    }
-                }
-            }
-        } catch (MessageException e) {
-            LOGGER.warn("[{}] Failed to send {} message with ID {} to peer {}: {}", this.peerConnectionId,
-                    message.getType().name(), message.getId(), this, e.getMessage());
-            return false;
-        } catch (IOException | InterruptedException e) {
+            // Possible race condition:
+            // We set OP_WRITE, EPC creates ChannelWriteTask which calls Peer.writeChannel, writeChannel's poll() finds no message to send
+            // Avoided by poll-with-timeout in writeChannel() above.
+            Network.getInstance().setInterestOps(this.socketChannel, SelectionKey.OP_WRITE);
+            return this.sendQueue.tryTransfer(message, timeout, TimeUnit.MILLISECONDS);
+        } catch (InterruptedException e) {
             // Send failure
             return false;
+        } catch (MessageException e) {
+            LOGGER.error(e.getMessage(), e);
+            return false;
         }
-
-        // Sent OK
-        return true;
     }
 
     /**
@@ -720,7 +766,7 @@ public class Peer {
         this.lastPingSent = NTP.getTime();
     }
 
-    protected ExecuteProduceConsume.Task getPingTask(Long now) {
+    protected Task getPingTask(Long now) {
         // Pings not enabled yet?
         if (now == null || this.lastPingSent == null) {
             return null;
@@ -734,19 +780,7 @@ public class Peer {
         // Not strictly true, but prevents this peer from being immediately chosen again
         this.lastPingSent = now;
 
-        return () -> {
-            PingMessage pingMessage = new PingMessage();
-            Message message = this.getResponse(pingMessage);
-
-            if (message == null || message.getType() != MessageType.PING) {
-                LOGGER.debug("[{}] Didn't receive reply from {} for PING ID {}", this.peerConnectionId, this,
-                        pingMessage.getId());
-                this.disconnect("no ping received");
-                return;
-            }
-
-            this.setLastPing(NTP.getTime() - now);
-        };
+        return new PingTask(this, now);
     }
 
     public void disconnect(String reason) {
@@ -877,6 +911,10 @@ public class Peer {
         return maxConnectionAge;
     }
 
+    public void setMaxConnectionAge(long maxConnectionAge) {
+        this.maxConnectionAge = maxConnectionAge;
+    }
+
     public boolean hasReachedMaxConnectionAge() {
         return this.getConnectionAge() > this.getMaxConnectionAge();
     }

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

@@ -9,38 +9,59 @@ import org.qortal.utils.Serialization;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.List;
 
 public class ArbitraryDataFileListMessage extends Message {
 
-	private static final int SIGNATURE_LENGTH = Transformer.SIGNATURE_LENGTH;
-	private static final int HASH_LENGTH = Transformer.SHA256_LENGTH;
-	private static final int MAX_PEER_ADDRESS_LENGTH = PeerData.MAX_PEER_ADDRESS_SIZE;
-
-	private final byte[] signature;
-	private final List<byte[]> hashes;
+	private byte[] signature;
+	private List<byte[]> hashes;
 	private Long requestTime;
 	private Integer requestHops;
 	private String peerAddress;
 	private Boolean isRelayPossible;
 
-
 	public ArbitraryDataFileListMessage(byte[] signature, List<byte[]> hashes, Long requestTime,
-										Integer requestHops, String peerAddress, boolean isRelayPossible) {
+										Integer requestHops, String peerAddress, Boolean isRelayPossible) {
 		super(MessageType.ARBITRARY_DATA_FILE_LIST);
 
-		this.signature = signature;
-		this.hashes = hashes;
-		this.requestTime = requestTime;
-		this.requestHops = requestHops;
-		this.peerAddress = peerAddress;
-		this.isRelayPossible = isRelayPossible;
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			bytes.write(signature);
+
+			bytes.write(Ints.toByteArray(hashes.size()));
+
+			for (byte[] hash : hashes) {
+				bytes.write(hash);
+			}
+
+			if (requestTime != null) {
+				// The remaining fields are optional
+
+				bytes.write(Longs.toByteArray(requestTime));
+
+				bytes.write(Ints.toByteArray(requestHops));
+
+				Serialization.serializeSizedStringV2(bytes, peerAddress);
+
+				bytes.write(Ints.toByteArray(Boolean.TRUE.equals(isRelayPossible) ? 1 : 0));
+			}
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
-	public ArbitraryDataFileListMessage(int id, byte[] signature, List<byte[]> hashes, Long requestTime,
+	/** Legacy version */
+	public ArbitraryDataFileListMessage(byte[] signature, List<byte[]> hashes) {
+		this(signature, hashes, null, null, null, null);
+	}
+
+	private ArbitraryDataFileListMessage(int id, byte[] signature, List<byte[]> hashes, Long requestTime,
 										Integer requestHops, String peerAddress, boolean isRelayPossible) {
 		super(id, MessageType.ARBITRARY_DATA_FILE_LIST);
 
@@ -52,24 +73,39 @@ public class ArbitraryDataFileListMessage extends Message {
 		this.isRelayPossible = isRelayPossible;
 	}
 
-	public List<byte[]> getHashes() {
-		return this.hashes;
-	}
-
 	public byte[] getSignature() {
 		return this.signature;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException, TransformationException {
-		byte[] signature = new byte[SIGNATURE_LENGTH];
+	public List<byte[]> getHashes() {
+		return this.hashes;
+	}
+
+	public Long getRequestTime() {
+		return this.requestTime;
+	}
+
+	public Integer getRequestHops() {
+		return this.requestHops;
+	}
+
+	public String getPeerAddress() {
+		return this.peerAddress;
+	}
+
+	public Boolean isRelayPossible() {
+		return this.isRelayPossible;
+	}
+
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws MessageException {
+		byte[] signature = new byte[Transformer.SIGNATURE_LENGTH];
 		bytes.get(signature);
 
 		int count = bytes.getInt();
 
 		List<byte[]> hashes = new ArrayList<>();
 		for (int i = 0; i < count; ++i) {
-
-			byte[] hash = new byte[HASH_LENGTH];
+			byte[] hash = new byte[Transformer.SHA256_LENGTH];
 			bytes.get(hash);
 			hashes.add(hash);
 		}
@@ -80,99 +116,21 @@ public class ArbitraryDataFileListMessage extends Message {
 		boolean isRelayPossible = true; // Legacy versions only send this message when relaying is possible
 
 		// The remaining fields are optional
-
 		if (bytes.hasRemaining()) {
+			try {
+				requestTime = bytes.getLong();
 
-			requestTime = bytes.getLong();
+				requestHops = bytes.getInt();
 
-			requestHops = bytes.getInt();
-
-			peerAddress = Serialization.deserializeSizedStringV2(bytes, MAX_PEER_ADDRESS_LENGTH);
-
-			isRelayPossible = bytes.getInt() > 0;
+				peerAddress = Serialization.deserializeSizedStringV2(bytes, PeerData.MAX_PEER_ADDRESS_SIZE);
 
+				isRelayPossible = bytes.getInt() > 0;
+			} catch (TransformationException e) {
+				throw new MessageException(e.getMessage(), e);
+			}
 		}
 
 		return new ArbitraryDataFileListMessage(id, signature, hashes, requestTime, requestHops, peerAddress, isRelayPossible);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(this.signature);
-
-			bytes.write(Ints.toByteArray(this.hashes.size()));
-
-			for (byte[] hash : this.hashes) {
-				bytes.write(hash);
-			}
-
-			if (this.requestTime == null) { // To maintain backwards support
-				return bytes.toByteArray();
-			}
-
-			// The remaining fields are optional
-
-			bytes.write(Longs.toByteArray(this.requestTime));
-
-			bytes.write(Ints.toByteArray(this.requestHops));
-
-			Serialization.serializeSizedStringV2(bytes, this.peerAddress);
-
-			bytes.write(Ints.toByteArray(this.isRelayPossible ? 1 : 0));
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
-	public ArbitraryDataFileListMessage cloneWithNewId(int newId) {
-		ArbitraryDataFileListMessage clone = new ArbitraryDataFileListMessage(this.signature, this.hashes,
-				this.requestTime, this.requestHops, this.peerAddress, this.isRelayPossible);
-		clone.setId(newId);
-		return clone;
-	}
-
-	public void removeOptionalStats() {
-		this.requestTime = null;
-		this.requestHops = null;
-		this.peerAddress = null;
-		this.isRelayPossible = null;
-	}
-
-	public Long getRequestTime() {
-		return this.requestTime;
-	}
-
-	public void setRequestTime(Long requestTime) {
-		this.requestTime = requestTime;
-	}
-
-	public Integer getRequestHops() {
-		return this.requestHops;
-	}
-
-	public void setRequestHops(Integer requestHops) {
-		this.requestHops = requestHops;
-	}
-
-	public String getPeerAddress() {
-		return this.peerAddress;
-	}
-
-	public void setPeerAddress(String peerAddress) {
-		this.peerAddress = peerAddress;
-	}
-
-	public Boolean isRelayPossible() {
-		return this.isRelayPossible;
-	}
-
-	public void setIsRelayPossible(Boolean isRelayPossible) {
-		this.isRelayPossible = isRelayPossible;
-	}
-
 }

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

@@ -9,44 +9,60 @@ import org.qortal.transform.Transformer;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
+import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
 
 public class ArbitraryDataFileMessage extends Message {
 
 	private static final Logger LOGGER = LogManager.getLogger(ArbitraryDataFileMessage.class);
 
-	private static final int SIGNATURE_LENGTH = Transformer.SIGNATURE_LENGTH;
-
-	private final byte[] signature;
-	private final ArbitraryDataFile arbitraryDataFile;
+	private byte[] signature;
+	private ArbitraryDataFile arbitraryDataFile;
 
 	public ArbitraryDataFileMessage(byte[] signature, ArbitraryDataFile arbitraryDataFile) {
 		super(MessageType.ARBITRARY_DATA_FILE);
 
-		this.signature = signature;
-		this.arbitraryDataFile = arbitraryDataFile;
+		byte[] data = arbitraryDataFile.getBytes();
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			bytes.write(signature);
+
+			bytes.write(Ints.toByteArray(data.length));
+
+			bytes.write(data);
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
-	public ArbitraryDataFileMessage(int id, byte[] signature, ArbitraryDataFile arbitraryDataFile) {
+	private ArbitraryDataFileMessage(int id, byte[] signature, ArbitraryDataFile arbitraryDataFile) {
 		super(id, MessageType.ARBITRARY_DATA_FILE);
 
 		this.signature = signature;
 		this.arbitraryDataFile = arbitraryDataFile;
 	}
 
+	public byte[] getSignature() {
+		return this.signature;
+	}
+
 	public ArbitraryDataFile getArbitraryDataFile() {
 		return this.arbitraryDataFile;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws UnsupportedEncodingException {
-		byte[] signature = new byte[SIGNATURE_LENGTH];
+	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws MessageException {
+		byte[] signature = new byte[Transformer.SIGNATURE_LENGTH];
 		byteBuffer.get(signature);
 
 		int dataLength = byteBuffer.getInt();
 
-		if (byteBuffer.remaining() != dataLength)
-			return null;
+		if (byteBuffer.remaining() < dataLength)
+			throw new BufferUnderflowException();
 
 		byte[] data = new byte[dataLength];
 		byteBuffer.get(data);
@@ -54,43 +70,10 @@ public class ArbitraryDataFileMessage extends Message {
 		try {
 			ArbitraryDataFile arbitraryDataFile = new ArbitraryDataFile(data, signature);
 			return new ArbitraryDataFileMessage(id, signature, arbitraryDataFile);
-		}
-		catch (DataException e) {
+		} catch (DataException e) {
 			LOGGER.info("Unable to process received file: {}", e.getMessage());
-			return null;
+			throw new MessageException("Unable to process received file: " + e.getMessage(), e);
 		}
 	}
 
-	@Override
-	protected byte[] toData() {
-		if (this.arbitraryDataFile == null) {
-			return null;
-		}
-
-		byte[] data = this.arbitraryDataFile.getBytes();
-		if (data == null) {
-			return null;
-		}
-
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(signature);
-
-			bytes.write(Ints.toByteArray(data.length));
-
-			bytes.write(data);
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
-	public ArbitraryDataFileMessage cloneWithNewId(int newId) {
-		ArbitraryDataFileMessage clone = new ArbitraryDataFileMessage(this.signature, this.arbitraryDataFile);
-		clone.setId(newId);
-		return clone;
-	}
-
 }

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

@@ -2,7 +2,7 @@ package org.qortal.network.message;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
+import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
 
 import org.qortal.transform.Transformer;
@@ -11,13 +11,26 @@ import com.google.common.primitives.Ints;
 
 public class ArbitraryDataMessage extends Message {
 
-	private static final int SIGNATURE_LENGTH = Transformer.SIGNATURE_LENGTH;
-
 	private byte[] signature;
 	private byte[] data;
 
 	public ArbitraryDataMessage(byte[] signature, byte[] data) {
-		this(-1, signature, data);
+		super(MessageType.ARBITRARY_DATA);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			bytes.write(signature);
+
+			bytes.write(Ints.toByteArray(data.length));
+
+			bytes.write(data);
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private ArbitraryDataMessage(int id, byte[] signature, byte[] data) {
@@ -35,14 +48,14 @@ public class ArbitraryDataMessage extends Message {
 		return this.data;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws UnsupportedEncodingException {
-		byte[] signature = new byte[SIGNATURE_LENGTH];
+	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) {
+		byte[] signature = new byte[Transformer.SIGNATURE_LENGTH];
 		byteBuffer.get(signature);
 
 		int dataLength = byteBuffer.getInt();
 
-		if (byteBuffer.remaining() != dataLength)
-			return null;
+		if (byteBuffer.remaining() < dataLength)
+			throw new BufferUnderflowException();
 
 		byte[] data = new byte[dataLength];
 		byteBuffer.get(data);
@@ -50,24 +63,4 @@ public class ArbitraryDataMessage extends Message {
 		return new ArbitraryDataMessage(id, signature, data);
 	}
 
-	@Override
-	protected byte[] toData() {
-		if (this.data == null)
-			return null;
-
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(this.signature);
-
-			bytes.write(Ints.toByteArray(this.data.length));
-
-			bytes.write(this.data);
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

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

@@ -7,28 +7,40 @@ import org.qortal.transform.Transformer;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
+import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
 
 public class ArbitraryMetadataMessage extends Message {
 
-	private static final int SIGNATURE_LENGTH = Transformer.SIGNATURE_LENGTH;
+	private byte[] signature;
+	private ArbitraryDataFile arbitraryMetadataFile;
 
-	private final byte[] signature;
-	private final ArbitraryDataFile arbitraryMetadataFile;
-
-	public ArbitraryMetadataMessage(byte[] signature, ArbitraryDataFile arbitraryDataFile) {
+	public ArbitraryMetadataMessage(byte[] signature, ArbitraryDataFile arbitraryMetadataFile) {
 		super(MessageType.ARBITRARY_METADATA);
 
-		this.signature = signature;
-		this.arbitraryMetadataFile = arbitraryDataFile;
+		byte[] data = arbitraryMetadataFile.getBytes();
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			bytes.write(signature);
+
+			bytes.write(Ints.toByteArray(data.length));
+
+			bytes.write(data);
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
-	public ArbitraryMetadataMessage(int id, byte[] signature, ArbitraryDataFile arbitraryDataFile) {
+	private ArbitraryMetadataMessage(int id, byte[] signature, ArbitraryDataFile arbitraryMetadataFile) {
 		super(id, MessageType.ARBITRARY_METADATA);
 
 		this.signature = signature;
-		this.arbitraryMetadataFile = arbitraryDataFile;
+		this.arbitraryMetadataFile = arbitraryMetadataFile;
 	}
 
 	public byte[] getSignature() {
@@ -39,14 +51,14 @@ public class ArbitraryMetadataMessage extends Message {
 		return this.arbitraryMetadataFile;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws UnsupportedEncodingException {
-		byte[] signature = new byte[SIGNATURE_LENGTH];
+	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws MessageException {
+		byte[] signature = new byte[Transformer.SIGNATURE_LENGTH];
 		byteBuffer.get(signature);
 
 		int dataLength = byteBuffer.getInt();
 
-		if (byteBuffer.remaining() != dataLength)
-			return null;
+		if (byteBuffer.remaining() < dataLength)
+			throw new BufferUnderflowException();
 
 		byte[] data = new byte[dataLength];
 		byteBuffer.get(data);
@@ -54,42 +66,9 @@ public class ArbitraryMetadataMessage extends Message {
 		try {
 			ArbitraryDataFile arbitraryMetadataFile = new ArbitraryDataFile(data, signature);
 			return new ArbitraryMetadataMessage(id, signature, arbitraryMetadataFile);
+		} catch (DataException e) {
+			throw new MessageException("Unable to process arbitrary metadata message: " + e.getMessage(), e);
 		}
-		catch (DataException e) {
-			return null;
-		}
-	}
-
-	@Override
-	protected byte[] toData() {
-		if (this.arbitraryMetadataFile == null) {
-			return null;
-		}
-
-		byte[] data = this.arbitraryMetadataFile.getBytes();
-		if (data == null) {
-			return null;
-		}
-
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(signature);
-
-			bytes.write(Ints.toByteArray(data.length));
-
-			bytes.write(data);
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
-	public ArbitraryMetadataMessage cloneWithNewId(int newId) {
-		ArbitraryMetadataMessage clone = new ArbitraryMetadataMessage(this.signature, this.arbitraryMetadataFile);
-		clone.setId(newId);
-		return clone;
 	}
 
 }

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

@@ -8,21 +8,37 @@ import org.qortal.utils.Serialization;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
+import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.List;
 
 public class ArbitrarySignaturesMessage extends Message {
 
-	private static final int SIGNATURE_LENGTH = Transformer.SIGNATURE_LENGTH;
-
 	private String peerAddress;
 	private int requestHops;
 	private List<byte[]> signatures;
 
 	public ArbitrarySignaturesMessage(String peerAddress, int requestHops, List<byte[]> signatures) {
-		this(-1, peerAddress, requestHops, signatures);
+		super(MessageType.ARBITRARY_SIGNATURES);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			Serialization.serializeSizedStringV2(bytes, peerAddress);
+
+			bytes.write(Ints.toByteArray(requestHops));
+
+			bytes.write(Ints.toByteArray(signatures.size()));
+
+			for (byte[] signature : signatures)
+				bytes.write(signature);
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private ArbitrarySignaturesMessage(int id, String peerAddress, int requestHops, List<byte[]> signatures) {
@@ -41,27 +57,24 @@ public class ArbitrarySignaturesMessage extends Message {
 		return this.signatures;
 	}
 
-	public int getRequestHops() {
-		return this.requestHops;
-	}
-
-	public void setRequestHops(int requestHops) {
-		this.requestHops = requestHops;
-	}
-
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException, TransformationException {
-		String peerAddress = Serialization.deserializeSizedStringV2(bytes, PeerData.MAX_PEER_ADDRESS_SIZE);
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws MessageException {
+		String peerAddress;
+		try {
+			peerAddress = Serialization.deserializeSizedStringV2(bytes, PeerData.MAX_PEER_ADDRESS_SIZE);
+		} catch (TransformationException e) {
+			throw new MessageException(e.getMessage(), e);
+		}
 
 		int requestHops = bytes.getInt();
 
 		int signatureCount = bytes.getInt();
 
-		if (bytes.remaining() != signatureCount * SIGNATURE_LENGTH)
-			return null;
+		if (bytes.remaining() < signatureCount * Transformer.SIGNATURE_LENGTH)
+			throw new BufferUnderflowException();
 
 		List<byte[]> signatures = new ArrayList<>();
 		for (int i = 0; i < signatureCount; ++i) {
-			byte[] signature = new byte[SIGNATURE_LENGTH];
+			byte[] signature = new byte[Transformer.SIGNATURE_LENGTH];
 			bytes.get(signature);
 			signatures.add(signature);
 		}
@@ -69,24 +82,4 @@ public class ArbitrarySignaturesMessage extends Message {
 		return new ArbitrarySignaturesMessage(id, peerAddress, requestHops, signatures);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			Serialization.serializeSizedStringV2(bytes, this.peerAddress);
-
-			bytes.write(Ints.toByteArray(this.requestHops));
-
-			bytes.write(Ints.toByteArray(this.signatures.size()));
-
-			for (byte[] signature : this.signatures)
-				bytes.write(signature);
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

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

@@ -1,14 +1,10 @@
 package org.qortal.network.message;
 
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 import java.util.List;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.qortal.block.Block;
 import org.qortal.data.at.ATStateData;
 import org.qortal.data.block.BlockData;
 import org.qortal.data.transaction.TransactionData;
@@ -16,27 +12,15 @@ import org.qortal.transform.TransformationException;
 import org.qortal.transform.block.BlockTransformer;
 import org.qortal.utils.Triple;
 
-import com.google.common.primitives.Ints;
-
 public class BlockMessage extends Message {
 
 	private static final Logger LOGGER = LogManager.getLogger(BlockMessage.class);
 
-	private Block block = null;
+	private final BlockData blockData;
+	private final List<TransactionData> transactions;
+	private final List<ATStateData> atStates;
 
-	private BlockData blockData = null;
-	private List<TransactionData> transactions = null;
-	private List<ATStateData> atStates = null;
-
-	private int height;
-
-	public BlockMessage(Block block) {
-		super(MessageType.BLOCK);
-
-		this.block = block;
-		this.blockData = block.getBlockData();
-		this.height = block.getBlockData().getHeight();
-	}
+	// No public constructor as we're an incoming-only message type.
 
 	private BlockMessage(int id, BlockData blockData, List<TransactionData> transactions, List<ATStateData> atStates) {
 		super(id, MessageType.BLOCK);
@@ -44,8 +28,6 @@ public class BlockMessage extends Message {
 		this.blockData = blockData;
 		this.transactions = transactions;
 		this.atStates = atStates;
-
-		this.height = blockData.getHeight();
 	}
 
 	public BlockData getBlockData() {
@@ -60,7 +42,7 @@ public class BlockMessage extends Message {
 		return this.atStates;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws UnsupportedEncodingException {
+	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws MessageException {
 		try {
 			int height = byteBuffer.getInt();
 
@@ -72,32 +54,8 @@ public class BlockMessage extends Message {
 			return new BlockMessage(id, blockData, blockInfo.getB(), blockInfo.getC());
 		} catch (TransformationException e) {
 			LOGGER.info(String.format("Received garbled BLOCK message: %s", e.getMessage()));
-			return null;
+			throw new MessageException(e.getMessage(), e);
 		}
 	}
 
-	@Override
-	protected byte[] toData() {
-		if (this.block == null)
-			return null;
-
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(Ints.toByteArray(this.height));
-
-			bytes.write(BlockTransformer.toBytes(this.block));
-
-			return bytes.toByteArray();
-		} catch (TransformationException | IOException e) {
-			return null;
-		}
-	}
-
-	public BlockMessage cloneWithNewId(int newId) {
-		BlockMessage clone = new BlockMessage(this.block);
-		clone.setId(newId);
-		return clone;
-	}
-
 }

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

@@ -2,7 +2,7 @@ package org.qortal.network.message;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
+import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.List;
@@ -20,7 +20,25 @@ public class BlockSummariesMessage extends Message {
 	private List<BlockSummaryData> blockSummaries;
 
 	public BlockSummariesMessage(List<BlockSummaryData> blockSummaries) {
-		this(-1, blockSummaries);
+		super(MessageType.BLOCK_SUMMARIES);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			bytes.write(Ints.toByteArray(blockSummaries.size()));
+
+			for (BlockSummaryData blockSummary : blockSummaries) {
+				bytes.write(Ints.toByteArray(blockSummary.getHeight()));
+				bytes.write(blockSummary.getSignature());
+				bytes.write(blockSummary.getMinterPublicKey());
+				bytes.write(Ints.toByteArray(blockSummary.getOnlineAccountsCount()));
+			}
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private BlockSummariesMessage(int id, List<BlockSummaryData> blockSummaries) {
@@ -33,11 +51,11 @@ public class BlockSummariesMessage extends Message {
 		return this.blockSummaries;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
 		int count = bytes.getInt();
 
-		if (bytes.remaining() != count * BLOCK_SUMMARY_LENGTH)
-			return null;
+		if (bytes.remaining() < count * BLOCK_SUMMARY_LENGTH)
+			throw new BufferUnderflowException();
 
 		List<BlockSummaryData> blockSummaries = new ArrayList<>();
 		for (int i = 0; i < count; ++i) {
@@ -58,24 +76,4 @@ public class BlockSummariesMessage extends Message {
 		return new BlockSummariesMessage(id, blockSummaries);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(Ints.toByteArray(this.blockSummaries.size()));
-
-			for (BlockSummaryData blockSummary : this.blockSummaries) {
-				bytes.write(Ints.toByteArray(blockSummary.getHeight()));
-				bytes.write(blockSummary.getSignature());
-				bytes.write(blockSummary.getMinterPublicKey());
-				bytes.write(Ints.toByteArray(blockSummary.getOnlineAccountsCount()));
-			}
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

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

@@ -2,7 +2,6 @@ package org.qortal.network.message;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 
 import org.qortal.block.Block;
@@ -12,59 +11,34 @@ import org.qortal.transform.block.BlockTransformer;
 import com.google.common.primitives.Ints;
 
 // This is an OUTGOING-only Message which more readily lends itself to being cached
-public class CachedBlockMessage extends Message {
+public class CachedBlockMessage extends Message implements Cloneable {
 
-	private Block block = null;
-	private byte[] cachedBytes = null;
-
-	public CachedBlockMessage(Block block) {
+	public CachedBlockMessage(Block block) throws TransformationException {
 		super(MessageType.BLOCK);
 
-		this.block = block;
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			bytes.write(Ints.toByteArray(block.getBlockData().getHeight()));
+
+			bytes.write(BlockTransformer.toBytes(block));
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	public CachedBlockMessage(byte[] cachedBytes) {
 		super(MessageType.BLOCK);
 
-		this.block = null;
-		this.cachedBytes = cachedBytes;
+		this.dataBytes = cachedBytes;
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
-	
-	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws UnsupportedEncodingException {
+
+	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) {
 		throw new UnsupportedOperationException("CachedBlockMessage is for outgoing messages only");
 	}
 
-	@Override
-	protected byte[] toData() {
-		// Already serialized?
-		if (this.cachedBytes != null)
-			return cachedBytes;
-
-		if (this.block == null)
-			return null;
-
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(Ints.toByteArray(this.block.getBlockData().getHeight()));
-
-			bytes.write(BlockTransformer.toBytes(this.block));
-
-			this.cachedBytes = bytes.toByteArray();
-			// We no longer need source Block
-			// and Block contains repository handle which is highly likely to be invalid after this call
-			this.block = null;
-
-			return this.cachedBytes;
-		} catch (TransformationException | IOException e) {
-			return null;
-		}
-	}
-
-	public CachedBlockMessage cloneWithNewId(int newId) {
-		CachedBlockMessage clone = new CachedBlockMessage(this.cachedBytes);
-		clone.setId(newId);
-		return clone;
-	}
-
 }

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

@@ -10,8 +10,25 @@ public class ChallengeMessage extends Message {
 
 	public static final int CHALLENGE_LENGTH = 32;
 
-	private final byte[] publicKey;
-	private final byte[] challenge;
+	private byte[] publicKey;
+	private byte[] challenge;
+
+	public ChallengeMessage(byte[] publicKey, byte[] challenge) {
+		super(MessageType.CHALLENGE);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream(publicKey.length + challenge.length);
+
+		try {
+			bytes.write(publicKey);
+
+			bytes.write(challenge);
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
+	}
 
 	private ChallengeMessage(int id, byte[] publicKey, byte[] challenge) {
 		super(id, MessageType.CHALLENGE);
@@ -20,10 +37,6 @@ public class ChallengeMessage extends Message {
 		this.challenge = challenge;
 	}
 
-	public ChallengeMessage(byte[] publicKey, byte[] challenge) {
-		this(-1, publicKey, challenge);
-	}
-
 	public byte[] getPublicKey() {
 		return this.publicKey;
 	}
@@ -42,15 +55,4 @@ public class ChallengeMessage extends Message {
 		return new ChallengeMessage(id, publicKey, challenge);
 	}
 
-	@Override
-	protected byte[] toData() throws IOException {
-		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-		bytes.write(this.publicKey);
-
-		bytes.write(this.challenge);
-
-		return bytes.toByteArray();
-	}
-
 }

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

@@ -5,33 +5,54 @@ import com.google.common.primitives.Longs;
 import org.qortal.data.network.PeerData;
 import org.qortal.transform.TransformationException;
 import org.qortal.transform.Transformer;
-import org.qortal.transform.transaction.TransactionTransformer;
 import org.qortal.utils.Serialization;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.List;
 
-import static org.qortal.transform.Transformer.INT_LENGTH;
-import static org.qortal.transform.Transformer.LONG_LENGTH;
-
 public class GetArbitraryDataFileListMessage extends Message {
 
-	private static final int SIGNATURE_LENGTH = Transformer.SIGNATURE_LENGTH;
-	private static final int HASH_LENGTH = TransactionTransformer.SHA256_LENGTH;
-	private static final int MAX_PEER_ADDRESS_LENGTH = PeerData.MAX_PEER_ADDRESS_SIZE;
-
-	private final byte[] signature;
+	private byte[] signature;
 	private List<byte[]> hashes;
-	private final long requestTime;
+	private long requestTime;
 	private int requestHops;
 	private String requestingPeer;
 
 	public GetArbitraryDataFileListMessage(byte[] signature, List<byte[]> hashes, long requestTime, int requestHops, String requestingPeer) {
-		this(-1, signature, hashes, requestTime, requestHops, requestingPeer);
+		super(MessageType.GET_ARBITRARY_DATA_FILE_LIST);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			bytes.write(signature);
+
+			bytes.write(Longs.toByteArray(requestTime));
+
+			bytes.write(Ints.toByteArray(requestHops));
+
+			if (hashes != null) {
+				bytes.write(Ints.toByteArray(hashes.size()));
+
+				for (byte[] hash : hashes) {
+					bytes.write(hash);
+				}
+			}
+			else {
+				bytes.write(Ints.toByteArray(0));
+			}
+
+			if (requestingPeer != null) {
+				Serialization.serializeSizedStringV2(bytes, requestingPeer);
+			}
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private GetArbitraryDataFileListMessage(int id, byte[] signature, List<byte[]> hashes, long requestTime, int requestHops, String requestingPeer) {
@@ -52,8 +73,20 @@ public class GetArbitraryDataFileListMessage extends Message {
 		return this.hashes;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException, TransformationException {
-		byte[] signature = new byte[SIGNATURE_LENGTH];
+	public long getRequestTime() {
+		return this.requestTime;
+	}
+
+	public int getRequestHops() {
+		return this.requestHops;
+	}
+
+	public String getRequestingPeer() {
+		return this.requestingPeer;
+	}
+
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws MessageException {
+		byte[] signature = new byte[Transformer.SIGNATURE_LENGTH];
 
 		bytes.get(signature);
 
@@ -67,7 +100,7 @@ public class GetArbitraryDataFileListMessage extends Message {
 
 			hashes = new ArrayList<>();
 			for (int i = 0; i < hashCount; ++i) {
-				byte[] hash = new byte[HASH_LENGTH];
+				byte[] hash = new byte[Transformer.SHA256_LENGTH];
 				bytes.get(hash);
 				hashes.add(hash);
 			}
@@ -75,57 +108,14 @@ public class GetArbitraryDataFileListMessage extends Message {
 
 		String requestingPeer = null;
 		if (bytes.hasRemaining()) {
-			requestingPeer = Serialization.deserializeSizedStringV2(bytes, MAX_PEER_ADDRESS_LENGTH);
+			try {
+				requestingPeer = Serialization.deserializeSizedStringV2(bytes, PeerData.MAX_PEER_ADDRESS_SIZE);
+			} catch (TransformationException e) {
+				throw new MessageException(e.getMessage(), e);
+			}
 		}
 
 		return new GetArbitraryDataFileListMessage(id, signature, hashes, requestTime, requestHops, requestingPeer);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(this.signature);
-
-			bytes.write(Longs.toByteArray(this.requestTime));
-
-			bytes.write(Ints.toByteArray(this.requestHops));
-
-			if (this.hashes != null) {
-				bytes.write(Ints.toByteArray(this.hashes.size()));
-
-				for (byte[] hash : this.hashes) {
-					bytes.write(hash);
-				}
-			}
-			else {
-				bytes.write(Ints.toByteArray(0));
-			}
-
-			if (this.requestingPeer != null) {
-				Serialization.serializeSizedStringV2(bytes, this.requestingPeer);
-			}
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
-	public long getRequestTime() {
-		return this.requestTime;
-	}
-
-	public int getRequestHops() {
-		return this.requestHops;
-	}
-	public void setRequestHops(int requestHops) {
-		this.requestHops = requestHops;
-	}
-
-	public String getRequestingPeer() {
-		return this.requestingPeer;
-	}
-
 }

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

@@ -1,23 +1,31 @@
 package org.qortal.network.message;
 
 import org.qortal.transform.Transformer;
-import org.qortal.transform.transaction.TransactionTransformer;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 
 public class GetArbitraryDataFileMessage extends Message {
 
-	private static final int SIGNATURE_LENGTH = Transformer.SIGNATURE_LENGTH;
-	private static final int HASH_LENGTH = TransactionTransformer.SHA256_LENGTH;
-
-	private final byte[] signature;
-	private final byte[] hash;
+	private byte[] signature;
+	private byte[] hash;
 
 	public GetArbitraryDataFileMessage(byte[] signature, byte[] hash) {
-		this(-1, signature, hash);
+		super(MessageType.GET_ARBITRARY_DATA_FILE);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream(signature.length + hash.length);
+
+		try {
+			bytes.write(signature);
+
+			bytes.write(hash);
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private GetArbitraryDataFileMessage(int id, byte[] signature, byte[] hash) {
@@ -35,32 +43,14 @@ public class GetArbitraryDataFileMessage extends Message {
 		return this.hash;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
-		if (bytes.remaining() != HASH_LENGTH + SIGNATURE_LENGTH)
-			return null;
-
-		byte[] signature = new byte[SIGNATURE_LENGTH];
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
+		byte[] signature = new byte[Transformer.SIGNATURE_LENGTH];
 		bytes.get(signature);
 
-		byte[] hash = new byte[HASH_LENGTH];
+		byte[] hash = new byte[Transformer.SHA256_LENGTH];
 		bytes.get(hash);
 
 		return new GetArbitraryDataFileMessage(id, signature, hash);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(this.signature);
-
-			bytes.write(this.hash);
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

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

@@ -1,20 +1,19 @@
 package org.qortal.network.message;
 
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
+import java.util.Arrays;
 
 import org.qortal.transform.Transformer;
 
 public class GetArbitraryDataMessage extends Message {
 
-	private static final int SIGNATURE_LENGTH = Transformer.SIGNATURE_LENGTH;
-
 	private byte[] signature;
 
 	public GetArbitraryDataMessage(byte[] signature) {
-		this(-1, signature);
+		super(MessageType.GET_ARBITRARY_DATA);
+
+		this.dataBytes = Arrays.copyOf(signature, signature.length);
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private GetArbitraryDataMessage(int id, byte[] signature) {
@@ -27,28 +26,12 @@ public class GetArbitraryDataMessage extends Message {
 		return this.signature;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
-		if (bytes.remaining() != SIGNATURE_LENGTH)
-			return null;
-
-		byte[] signature = new byte[SIGNATURE_LENGTH];
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
+		byte[] signature = new byte[Transformer.SIGNATURE_LENGTH];
 
 		bytes.get(signature);
 
 		return new GetArbitraryDataMessage(id, signature);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(this.signature);
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

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

@@ -6,22 +6,31 @@ import org.qortal.transform.Transformer;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 
-import static org.qortal.transform.Transformer.INT_LENGTH;
-import static org.qortal.transform.Transformer.LONG_LENGTH;
-
 public class GetArbitraryMetadataMessage extends Message {
 
-	private static final int SIGNATURE_LENGTH = Transformer.SIGNATURE_LENGTH;
-
-	private final byte[] signature;
-	private final long requestTime;
+	private byte[] signature;
+	private long requestTime;
 	private int requestHops;
 
 	public GetArbitraryMetadataMessage(byte[] signature, long requestTime, int requestHops) {
-		this(-1, signature, requestTime, requestHops);
+		super(MessageType.GET_ARBITRARY_METADATA);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			bytes.write(signature);
+
+			bytes.write(Longs.toByteArray(requestTime));
+
+			bytes.write(Ints.toByteArray(requestHops));
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private GetArbitraryMetadataMessage(int id, byte[] signature, long requestTime, int requestHops) {
@@ -36,12 +45,16 @@ public class GetArbitraryMetadataMessage extends Message {
 		return this.signature;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
-		if (bytes.remaining() != SIGNATURE_LENGTH + LONG_LENGTH + INT_LENGTH)
-			return null;
+	public long getRequestTime() {
+		return this.requestTime;
+	}
 
-		byte[] signature = new byte[SIGNATURE_LENGTH];
+	public int getRequestHops() {
+		return this.requestHops;
+	}
 
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
+		byte[] signature = new byte[Transformer.SIGNATURE_LENGTH];
 		bytes.get(signature);
 
 		long requestTime = bytes.getLong();
@@ -51,33 +64,4 @@ public class GetArbitraryMetadataMessage extends Message {
 		return new GetArbitraryMetadataMessage(id, signature, requestTime, requestHops);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(this.signature);
-
-			bytes.write(Longs.toByteArray(this.requestTime));
-
-			bytes.write(Ints.toByteArray(this.requestHops));
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
-	public long getRequestTime() {
-		return this.requestTime;
-	}
-
-	public int getRequestHops() {
-		return this.requestHops;
-	}
-
-	public void setRequestHops(int requestHops) {
-		this.requestHops = requestHops;
-	}
-
 }

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

@@ -1,20 +1,19 @@
 package org.qortal.network.message;
 
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
+import java.util.Arrays;
 
 import org.qortal.transform.block.BlockTransformer;
 
 public class GetBlockMessage extends Message {
 
-	private static final int BLOCK_SIGNATURE_LENGTH = BlockTransformer.BLOCK_SIGNATURE_LENGTH;
-
 	private byte[] signature;
 
 	public GetBlockMessage(byte[] signature) {
-		this(-1, signature);
+		super(MessageType.GET_BLOCK);
+
+		this.dataBytes = Arrays.copyOf(signature, signature.length);
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private GetBlockMessage(int id, byte[] signature) {
@@ -27,28 +26,11 @@ public class GetBlockMessage extends Message {
 		return this.signature;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
-		if (bytes.remaining() != BLOCK_SIGNATURE_LENGTH)
-			return null;
-
-		byte[] signature = new byte[BLOCK_SIGNATURE_LENGTH];
-
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
+		byte[] signature = new byte[BlockTransformer.BLOCK_SIGNATURE_LENGTH];
 		bytes.get(signature);
 
 		return new GetBlockMessage(id, signature);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(this.signature);
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

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

@@ -2,23 +2,32 @@ package org.qortal.network.message;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 
-import org.qortal.transform.Transformer;
 import org.qortal.transform.block.BlockTransformer;
 
 import com.google.common.primitives.Ints;
 
 public class GetBlockSummariesMessage extends Message {
 
-	private static final int BLOCK_SIGNATURE_LENGTH = BlockTransformer.BLOCK_SIGNATURE_LENGTH;
-
 	private byte[] parentSignature;
 	private int numberRequested;
 
 	public GetBlockSummariesMessage(byte[] parentSignature, int numberRequested) {
-		this(-1, parentSignature, numberRequested);
+		super(MessageType.GET_BLOCK_SUMMARIES);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			bytes.write(parentSignature);
+
+			bytes.write(Ints.toByteArray(numberRequested));
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private GetBlockSummariesMessage(int id, byte[] parentSignature, int numberRequested) {
@@ -36,11 +45,8 @@ public class GetBlockSummariesMessage extends Message {
 		return this.numberRequested;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
-		if (bytes.remaining() != BLOCK_SIGNATURE_LENGTH + Transformer.INT_LENGTH)
-			return null;
-
-		byte[] parentSignature = new byte[BLOCK_SIGNATURE_LENGTH];
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
+		byte[] parentSignature = new byte[BlockTransformer.BLOCK_SIGNATURE_LENGTH];
 		bytes.get(parentSignature);
 
 		int numberRequested = bytes.getInt();
@@ -48,19 +54,4 @@ public class GetBlockSummariesMessage extends Message {
 		return new GetBlockSummariesMessage(id, parentSignature, numberRequested);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(this.parentSignature);
-
-			bytes.write(Ints.toByteArray(this.numberRequested));
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

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

@@ -2,7 +2,6 @@ package org.qortal.network.message;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.List;
@@ -20,7 +19,24 @@ public class GetOnlineAccountsMessage extends Message {
 	private List<OnlineAccountData> onlineAccounts;
 
 	public GetOnlineAccountsMessage(List<OnlineAccountData> onlineAccounts) {
-		this(-1, onlineAccounts);
+		super(MessageType.GET_ONLINE_ACCOUNTS);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			bytes.write(Ints.toByteArray(onlineAccounts.size()));
+
+			for (OnlineAccountData onlineAccountData : onlineAccounts) {
+				bytes.write(Longs.toByteArray(onlineAccountData.getTimestamp()));
+
+				bytes.write(onlineAccountData.getPublicKey());
+			}
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private GetOnlineAccountsMessage(int id, List<OnlineAccountData> onlineAccounts) {
@@ -33,7 +49,7 @@ public class GetOnlineAccountsMessage extends Message {
 		return this.onlineAccounts;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
 		final int accountCount = bytes.getInt();
 
 		List<OnlineAccountData> onlineAccounts = new ArrayList<>(accountCount);
@@ -50,24 +66,4 @@ public class GetOnlineAccountsMessage extends Message {
 		return new GetOnlineAccountsMessage(id, onlineAccounts);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(Ints.toByteArray(this.onlineAccounts.size()));
-
-			for (int i = 0; i < this.onlineAccounts.size(); ++i) {
-				OnlineAccountData onlineAccountData = this.onlineAccounts.get(i);
-				bytes.write(Longs.toByteArray(onlineAccountData.getTimestamp()));
-
-				bytes.write(onlineAccountData.getPublicKey());
-			}
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

src/main/java/org/qortal/network/message/GetOnlineAccountsV2Message.java

@@ -7,7 +7,6 @@ import org.qortal.transform.Transformer;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -24,11 +23,51 @@ import java.util.Map;
  * Also V2 only builds online accounts message once!
  */
 public class GetOnlineAccountsV2Message extends Message {
+
 	private List<OnlineAccountData> onlineAccounts;
-	private byte[] cachedData;
 
 	public GetOnlineAccountsV2Message(List<OnlineAccountData> onlineAccounts) {
-		this(-1, onlineAccounts);
+		super(MessageType.GET_ONLINE_ACCOUNTS_V2);
+
+		// If we don't have ANY online accounts then it's an easier construction...
+		if (onlineAccounts.isEmpty()) {
+			// Always supply a number of accounts
+			this.dataBytes = Ints.toByteArray(0);
+			this.checksumBytes = Message.generateChecksum(this.dataBytes);
+			return;
+		}
+
+		// How many of each timestamp
+		Map<Long, Integer> countByTimestamp = new HashMap<>();
+
+		for (OnlineAccountData onlineAccountData : onlineAccounts) {
+			Long timestamp = onlineAccountData.getTimestamp();
+			countByTimestamp.compute(timestamp, (k, v) -> v == null ? 1 : ++v);
+		}
+
+		// We should know exactly how many bytes to allocate now
+		int byteSize = countByTimestamp.size() * (Transformer.INT_LENGTH + Transformer.TIMESTAMP_LENGTH)
+				+ onlineAccounts.size() * Transformer.PUBLIC_KEY_LENGTH;
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream(byteSize);
+
+		try {
+			for (long timestamp : countByTimestamp.keySet()) {
+				bytes.write(Ints.toByteArray(countByTimestamp.get(timestamp)));
+
+				bytes.write(Longs.toByteArray(timestamp));
+
+				for (OnlineAccountData onlineAccountData : onlineAccounts) {
+					if (onlineAccountData.getTimestamp() == timestamp)
+						bytes.write(onlineAccountData.getPublicKey());
+				}
+			}
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private GetOnlineAccountsV2Message(int id, List<OnlineAccountData> onlineAccounts) {
@@ -41,7 +80,7 @@ public class GetOnlineAccountsV2Message extends Message {
 		return this.onlineAccounts;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
 		int accountCount = bytes.getInt();
 
 		List<OnlineAccountData> onlineAccounts = new ArrayList<>(accountCount);
@@ -67,51 +106,4 @@ public class GetOnlineAccountsV2Message extends Message {
 		return new GetOnlineAccountsV2Message(id, onlineAccounts);
 	}
 
-	@Override
-	protected synchronized byte[] toData() {
-		if (this.cachedData != null)
-			return this.cachedData;
-
-		// Shortcut in case we have no online accounts
-		if (this.onlineAccounts.isEmpty()) {
-			this.cachedData = Ints.toByteArray(0);
-			return this.cachedData;
-		}
-
-		// How many of each timestamp
-		Map<Long, Integer> countByTimestamp = new HashMap<>();
-
-		for (int i = 0; i < this.onlineAccounts.size(); ++i) {
-			OnlineAccountData onlineAccountData = this.onlineAccounts.get(i);
-			Long timestamp = onlineAccountData.getTimestamp();
-			countByTimestamp.compute(timestamp, (k, v) -> v == null ? 1 : ++v);
-		}
-
-		// We should know exactly how many bytes to allocate now
-		int byteSize = countByTimestamp.size() * (Transformer.INT_LENGTH + Transformer.TIMESTAMP_LENGTH)
-				+ this.onlineAccounts.size() * Transformer.PUBLIC_KEY_LENGTH;
-
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream(byteSize);
-
-			for (long timestamp : countByTimestamp.keySet()) {
-				bytes.write(Ints.toByteArray(countByTimestamp.get(timestamp)));
-
-				bytes.write(Longs.toByteArray(timestamp));
-
-				for (int i = 0; i < this.onlineAccounts.size(); ++i) {
-					OnlineAccountData onlineAccountData = this.onlineAccounts.get(i);
-
-					if (onlineAccountData.getTimestamp() == timestamp)
-						bytes.write(onlineAccountData.getPublicKey());
-				}
-			}
-
-			this.cachedData = bytes.toByteArray();
-			return this.cachedData;
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

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

@@ -1,25 +1,21 @@
 package org.qortal.network.message;
 
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 
 public class GetPeersMessage extends Message {
 
 	public GetPeersMessage() {
-		this(-1);
+		super(MessageType.GET_PEERS);
+
+		this.dataBytes = EMPTY_DATA_BYTES;
 	}
 
 	private GetPeersMessage(int id) {
 		super(id, MessageType.GET_PEERS);
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
 		return new GetPeersMessage(id);
 	}
 
-	@Override
-	protected byte[] toData() {
-		return new byte[0];
-	}
-
 }

src/main/java/org/qortal/network/message/GetSignaturesV2Message.java

@@ -2,24 +2,32 @@ package org.qortal.network.message;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 
-import org.qortal.transform.Transformer;
 import org.qortal.transform.block.BlockTransformer;
 
 import com.google.common.primitives.Ints;
 
 public class GetSignaturesV2Message extends Message {
 
-	private static final int BLOCK_SIGNATURE_LENGTH = BlockTransformer.BLOCK_SIGNATURE_LENGTH;
-	private static final int NUMBER_REQUESTED_LENGTH = Transformer.INT_LENGTH;
-
 	private byte[] parentSignature;
 	private int numberRequested;
 
 	public GetSignaturesV2Message(byte[] parentSignature, int numberRequested) {
-		this(-1, parentSignature, numberRequested);
+		super(MessageType.GET_SIGNATURES_V2);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			bytes.write(parentSignature);
+
+			bytes.write(Ints.toByteArray(numberRequested));
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private GetSignaturesV2Message(int id, byte[] parentSignature, int numberRequested) {
@@ -37,11 +45,8 @@ public class GetSignaturesV2Message extends Message {
 		return this.numberRequested;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
-		if (bytes.remaining() != BLOCK_SIGNATURE_LENGTH + NUMBER_REQUESTED_LENGTH)
-			return null;
-
-		byte[] parentSignature = new byte[BLOCK_SIGNATURE_LENGTH];
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
+		byte[] parentSignature = new byte[BlockTransformer.BLOCK_SIGNATURE_LENGTH];
 		bytes.get(parentSignature);
 
 		int numberRequested = bytes.getInt();
@@ -49,19 +54,4 @@ public class GetSignaturesV2Message extends Message {
 		return new GetSignaturesV2Message(id, parentSignature, numberRequested);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(this.parentSignature);
-
-			bytes.write(Ints.toByteArray(this.numberRequested));
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

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

@@ -7,7 +7,6 @@ import org.qortal.transform.Transformer;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -21,10 +20,48 @@ import java.util.Map;
  */
 public class GetTradePresencesMessage extends Message {
 	private List<TradePresenceData> tradePresences;
-	private byte[] cachedData;
 
 	public GetTradePresencesMessage(List<TradePresenceData> tradePresences) {
-		this(-1, tradePresences);
+		super(MessageType.GET_TRADE_PRESENCES);
+
+		// Shortcut in case we have no trade presences
+		if (tradePresences.isEmpty()) {
+			this.dataBytes = Ints.toByteArray(0);
+			this.checksumBytes = Message.generateChecksum(this.dataBytes);
+			return;
+		}
+
+		// How many of each timestamp
+		Map<Long, Integer> countByTimestamp = new HashMap<>();
+
+		for (TradePresenceData tradePresenceData : tradePresences) {
+			Long timestamp = tradePresenceData.getTimestamp();
+			countByTimestamp.compute(timestamp, (k, v) -> v == null ? 1 : ++v);
+		}
+
+		// We should know exactly how many bytes to allocate now
+		int byteSize = countByTimestamp.size() * (Transformer.INT_LENGTH + Transformer.TIMESTAMP_LENGTH)
+				+ tradePresences.size() * Transformer.PUBLIC_KEY_LENGTH;
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream(byteSize);
+
+		try {
+			for (long timestamp : countByTimestamp.keySet()) {
+				bytes.write(Ints.toByteArray(countByTimestamp.get(timestamp)));
+
+				bytes.write(Longs.toByteArray(timestamp));
+
+				for (TradePresenceData tradePresenceData : tradePresences) {
+					if (tradePresenceData.getTimestamp() == timestamp)
+						bytes.write(tradePresenceData.getPublicKey());
+				}
+			}
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private GetTradePresencesMessage(int id, List<TradePresenceData> tradePresences) {
@@ -37,7 +74,7 @@ public class GetTradePresencesMessage extends Message {
 		return this.tradePresences;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
 		int groupedEntriesCount = bytes.getInt();
 
 		List<TradePresenceData> tradePresences = new ArrayList<>(groupedEntriesCount);
@@ -63,48 +100,4 @@ public class GetTradePresencesMessage extends Message {
 		return new GetTradePresencesMessage(id, tradePresences);
 	}
 
-	@Override
-	protected synchronized byte[] toData() {
-		if (this.cachedData != null)
-			return this.cachedData;
-
-		// Shortcut in case we have no trade presences
-		if (this.tradePresences.isEmpty()) {
-			this.cachedData = Ints.toByteArray(0);
-			return this.cachedData;
-		}
-
-		// How many of each timestamp
-		Map<Long, Integer> countByTimestamp = new HashMap<>();
-
-		for (TradePresenceData tradePresenceData : this.tradePresences) {
-			Long timestamp = tradePresenceData.getTimestamp();
-			countByTimestamp.compute(timestamp, (k, v) -> v == null ? 1 : ++v);
-		}
-
-		// We should know exactly how many bytes to allocate now
-		int byteSize = countByTimestamp.size() * (Transformer.INT_LENGTH + Transformer.TIMESTAMP_LENGTH)
-				+ this.tradePresences.size() * Transformer.PUBLIC_KEY_LENGTH;
-
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream(byteSize);
-
-			for (long timestamp : countByTimestamp.keySet()) {
-				bytes.write(Ints.toByteArray(countByTimestamp.get(timestamp)));
-
-				bytes.write(Longs.toByteArray(timestamp));
-
-				for (TradePresenceData tradePresenceData : this.tradePresences) {
-					if (tradePresenceData.getTimestamp() == timestamp)
-						bytes.write(tradePresenceData.getPublicKey());
-				}
-			}
-
-			this.cachedData = bytes.toByteArray();
-			return this.cachedData;
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

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

@@ -1,20 +1,19 @@
 package org.qortal.network.message;
 
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
+import java.util.Arrays;
 
 import org.qortal.transform.Transformer;
 
 public class GetTransactionMessage extends Message {
 
-	private static final int TRANSACTION_SIGNATURE_LENGTH = Transformer.SIGNATURE_LENGTH;
-
 	private byte[] signature;
 
 	public GetTransactionMessage(byte[] signature) {
-		this(-1, signature);
+		super(MessageType.GET_TRANSACTION);
+
+		this.dataBytes = Arrays.copyOf(signature, signature.length);
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private GetTransactionMessage(int id, byte[] signature) {
@@ -27,28 +26,12 @@ public class GetTransactionMessage extends Message {
 		return this.signature;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
-		if (bytes.remaining() != TRANSACTION_SIGNATURE_LENGTH)
-			return null;
-
-		byte[] signature = new byte[TRANSACTION_SIGNATURE_LENGTH];
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
+		byte[] signature = new byte[Transformer.SIGNATURE_LENGTH];
 
 		bytes.get(signature);
 
 		return new GetTransactionMessage(id, signature);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(this.signature);
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

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

@@ -1,25 +1,21 @@
 package org.qortal.network.message;
 
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 
 public class GetUnconfirmedTransactionsMessage extends Message {
 
 	public GetUnconfirmedTransactionsMessage() {
-		this(-1);
+		super(MessageType.GET_UNCONFIRMED_TRANSACTIONS);
+
+		this.dataBytes = EMPTY_DATA_BYTES;
 	}
 
 	private GetUnconfirmedTransactionsMessage(int id) {
 		super(id, MessageType.GET_UNCONFIRMED_TRANSACTIONS);
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
 		return new GetUnconfirmedTransactionsMessage(id);
 	}
 
-	@Override
-	protected byte[] toData() {
-		return new byte[0];
-	}
-
 }

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

@@ -3,7 +3,6 @@ package org.qortal.network.message;
 import static java.util.Arrays.stream;
 import static java.util.stream.Collectors.toMap;
 
-import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.Map;
 
@@ -22,7 +21,7 @@ public class GoodbyeMessage extends Message {
 		private static final Map<Integer, Reason> map = stream(Reason.values())
 				.collect(toMap(reason -> reason.value, reason -> reason));
 
-		private Reason(int value) {
+		Reason(int value) {
 			this.value = value;
 		}
 
@@ -31,7 +30,14 @@ public class GoodbyeMessage extends Message {
 		}
 	}
 
-	private final Reason reason;
+	private Reason reason;
+
+	public GoodbyeMessage(Reason reason) {
+		super(MessageType.GOODBYE);
+
+		this.dataBytes = Ints.toByteArray(reason.value);
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
+	}
 
 	private GoodbyeMessage(int id, Reason reason) {
 		super(id, MessageType.GOODBYE);
@@ -39,27 +45,18 @@ public class GoodbyeMessage extends Message {
 		this.reason = reason;
 	}
 
-	public GoodbyeMessage(Reason reason) {
-		this(-1, reason);
-	}
-
 	public Reason getReason() {
 		return this.reason;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) {
+	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws MessageException {
 		int reasonValue = byteBuffer.getInt();
 
 		Reason reason = Reason.valueOf(reasonValue);
 		if (reason == null)
-			return null;
+			throw new MessageException("Invalid reason " + reasonValue + " in GOODBYE message");
 
 		return new GoodbyeMessage(id, reason);
 	}
 
-	@Override
-	protected byte[] toData() throws IOException {
-		return Ints.toByteArray(this.reason.value);
-	}
-
 }

src/main/java/org/qortal/network/message/HeightV2Message.java

@@ -2,7 +2,6 @@ package org.qortal.network.message;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 
 import org.qortal.transform.Transformer;
@@ -19,7 +18,24 @@ public class HeightV2Message extends Message {
 	private byte[] minterPublicKey;
 
 	public HeightV2Message(int height, byte[] signature, long timestamp, byte[] minterPublicKey) {
-		this(-1, height, signature, timestamp, minterPublicKey);
+		super(MessageType.HEIGHT_V2);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			bytes.write(Ints.toByteArray(height));
+
+			bytes.write(signature);
+
+			bytes.write(Longs.toByteArray(timestamp));
+
+			bytes.write(minterPublicKey);
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private HeightV2Message(int id, int height, byte[] signature, long timestamp, byte[] minterPublicKey) {
@@ -47,7 +63,7 @@ public class HeightV2Message extends Message {
 		return this.minterPublicKey;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
 		int height = bytes.getInt();
 
 		byte[] signature = new byte[BlockTransformer.BLOCK_SIGNATURE_LENGTH];
@@ -61,23 +77,4 @@ public class HeightV2Message extends Message {
 		return new HeightV2Message(id, height, signature, timestamp, minterPublicKey);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(Ints.toByteArray(this.height));
-
-			bytes.write(this.signature);
-
-			bytes.write(Longs.toByteArray(this.timestamp));
-
-			bytes.write(this.minterPublicKey);
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

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

@@ -11,9 +11,28 @@ import com.google.common.primitives.Longs;
 
 public class HelloMessage extends Message {
 
-	private final long timestamp;
-	private final String versionString;
-	private final String senderPeerAddress;
+	private long timestamp;
+	private String versionString;
+	private String senderPeerAddress;
+
+	public HelloMessage(long timestamp, String versionString, String senderPeerAddress) {
+		super(MessageType.HELLO);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			bytes.write(Longs.toByteArray(timestamp));
+
+			Serialization.serializeSizedString(bytes, versionString);
+
+			Serialization.serializeSizedString(bytes, senderPeerAddress);
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
+	}
 
 	private HelloMessage(int id, long timestamp, String versionString, String senderPeerAddress) {
 		super(id, MessageType.HELLO);
@@ -23,10 +42,6 @@ public class HelloMessage extends Message {
 		this.senderPeerAddress = senderPeerAddress;
 	}
 
-	public HelloMessage(long timestamp, String versionString, String senderPeerAddress) {
-		this(-1, timestamp, versionString, senderPeerAddress);
-	}
-
 	public long getTimestamp() {
 		return this.timestamp;
 	}
@@ -39,31 +54,23 @@ public class HelloMessage extends Message {
 		return this.senderPeerAddress;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws TransformationException {
+	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws MessageException {
 		long timestamp = byteBuffer.getLong();
 
-		String versionString = Serialization.deserializeSizedString(byteBuffer, 255);
-
-		// Sender peer address added in v3.0, so is an optional field. Older versions won't send it.
+		String versionString;
 		String senderPeerAddress = null;
-		if (byteBuffer.hasRemaining()) {
-			senderPeerAddress = Serialization.deserializeSizedString(byteBuffer, 255);
+		try {
+			versionString = Serialization.deserializeSizedString(byteBuffer, 255);
+
+			// Sender peer address added in v3.0, so is an optional field. Older versions won't send it.
+			if (byteBuffer.hasRemaining()) {
+				senderPeerAddress = Serialization.deserializeSizedString(byteBuffer, 255);
+			}
+		} catch (TransformationException e) {
+			throw new MessageException(e.getMessage(), e);
 		}
 
 		return new HelloMessage(id, timestamp, versionString, senderPeerAddress);
 	}
 
-	@Override
-	protected byte[] toData() throws IOException {
-		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-		bytes.write(Longs.toByteArray(this.timestamp));
-
-		Serialization.serializeSizedString(bytes, this.versionString);
-
-		Serialization.serializeSizedString(bytes, this.senderPeerAddress);
-
-		return bytes.toByteArray();
-	}
-
 }

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

@@ -1,161 +1,67 @@
 package org.qortal.network.message;
 
-import java.util.Map;
-
 import org.qortal.crypto.Crypto;
 import org.qortal.network.Network;
-import org.qortal.transform.TransformationException;
 
 import com.google.common.primitives.Ints;
 
-import static java.util.Arrays.stream;
-import static java.util.stream.Collectors.toMap;
-
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
 import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
 import java.util.Arrays;
 
+/**
+ * Network message for sending over network, or unpacked data received from network.
+ * <p></p>
+ * <p>
+ * For messages received from network, subclass's {@code fromByteBuffer()} method is used
+ * to construct a subclassed instance. Original bytes from network are not retained.
+ * Access to deserialized data should be via subclass's getters. Ideally there should be NO setters!
+ * </p>
+ * <p></p>
+ * <p>
+ * Each subclass's <b>public</b> constructor is for building a message to send <b>only</b>.
+ * The constructor will serialize into byte form but <b>not</b> store the passed args.
+ * Serialized bytes are saved into superclass (Message) {@code dataBytes} and, if not empty,
+ * a checksum is created and saved into {@code checksumBytes}.
+ * Therefore: <i>do not use subclass's getters after using constructor!</i>
+ * </p>
+ * <p></p>
+ * <p>
+ * For subclasses where outgoing versions might be usefully cached, they can implement Clonable
+ * as long if they are safe to use {@link Object#clone()}.
+ * </p>
+ */
 public abstract class Message {
 
 	// MAGIC(4) + TYPE(4) + HAS-ID(1) + ID?(4) + DATA-SIZE(4) + CHECKSUM?(4) + DATA?(*)
 	private static final int MAGIC_LENGTH = 4;
+	private static final int TYPE_LENGTH = 4;
+	private static final int HAS_ID_LENGTH = 1;
+	private static final int ID_LENGTH = 4;
+	private static final int DATA_SIZE_LENGTH = 4;
 	private static final int CHECKSUM_LENGTH = 4;
 
 	private static final int MAX_DATA_SIZE = 10 * 1024 * 1024; // 10MB
 
-	@SuppressWarnings("serial")
-	public static class MessageException extends Exception {
-		public MessageException() {
-		}
+	protected static final byte[] EMPTY_DATA_BYTES = new byte[0];
 
-		public MessageException(String message) {
-			super(message);
-		}
+	protected int id;
+	protected final MessageType type;
 
-		public MessageException(String message, Throwable cause) {
-			super(message, cause);
-		}
-
-		public MessageException(Throwable cause) {
-			super(cause);
-		}
-	}
-
-	public enum MessageType {
-		// Handshaking
-		HELLO(0),
-		GOODBYE(1),
-		CHALLENGE(2),
-		RESPONSE(3),
-
-		// Status / notifications
-		HEIGHT_V2(10),
-		PING(11),
-		PONG(12),
-
-		// Requesting data
-		PEERS_V2(20),
-		GET_PEERS(21),
-
-		TRANSACTION(30),
-		GET_TRANSACTION(31),
-
-		TRANSACTION_SIGNATURES(40),
-		GET_UNCONFIRMED_TRANSACTIONS(41),
-
-		BLOCK(50),
-		GET_BLOCK(51),
-
-		SIGNATURES(60),
-		GET_SIGNATURES_V2(61),
-
-		BLOCK_SUMMARIES(70),
-		GET_BLOCK_SUMMARIES(71),
-
-		ONLINE_ACCOUNTS(80),
-		GET_ONLINE_ACCOUNTS(81),
-		ONLINE_ACCOUNTS_V2(82),
-		GET_ONLINE_ACCOUNTS_V2(83),
-
-		ARBITRARY_DATA(90),
-		GET_ARBITRARY_DATA(91),
-
-		BLOCKS(100),
-		GET_BLOCKS(101),
-
-		ARBITRARY_DATA_FILE(110),
-		GET_ARBITRARY_DATA_FILE(111),
-
-		ARBITRARY_DATA_FILE_LIST(120),
-		GET_ARBITRARY_DATA_FILE_LIST(121),
-
-		ARBITRARY_SIGNATURES(130),
-
-		TRADE_PRESENCES(140),
-		GET_TRADE_PRESENCES(141),
-		
-		ARBITRARY_METADATA(150),
-		GET_ARBITRARY_METADATA(151);
-
-		public final int value;
-		public final Method fromByteBufferMethod;
-
-		private static final Map<Integer, MessageType> map = stream(MessageType.values())
-				.collect(toMap(messageType -> messageType.value, messageType -> messageType));
-
-		private MessageType(int value) {
-			this.value = value;
-
-			String[] classNameParts = this.name().toLowerCase().split("_");
-
-			for (int i = 0; i < classNameParts.length; ++i)
-				classNameParts[i] = classNameParts[i].substring(0, 1).toUpperCase().concat(classNameParts[i].substring(1));
-
-			String className = String.join("", classNameParts);
-
-			Method method;
-			try {
-				Class<?> subclass = Class.forName(String.join("", Message.class.getPackage().getName(), ".", className, "Message"));
-
-				method = subclass.getDeclaredMethod("fromByteBuffer", int.class, ByteBuffer.class);
-			} catch (ClassNotFoundException | NoSuchMethodException | SecurityException e) {
-				method = null;
-			}
-
-			this.fromByteBufferMethod = method;
-		}
-
-		public static MessageType valueOf(int value) {
-			return map.get(value);
-		}
-
-		public Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws MessageException {
-			if (this.fromByteBufferMethod == null)
-				throw new MessageException("Unsupported message type [" + value + "] during conversion from bytes");
-
-			try {
-				return (Message) this.fromByteBufferMethod.invoke(null, id, byteBuffer);
-			} catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
-				if (e.getCause() instanceof BufferUnderflowException)
-					throw new MessageException("Byte data too short for " + name() + " message");
-
-				throw new MessageException("Internal error with " + name() + " message during conversion from bytes");
-			}
-		}
-	}
-
-	private int id;
-	private MessageType type;
+	/** Serialized outgoing message data. Expected to be written to by subclass. */
+	protected byte[] dataBytes;
+	/** Serialized outgoing message checksum. Expected to be written to by subclass. */
+	protected byte[] checksumBytes;
 
+	/** Typically called by subclass when constructing message from received network data. */
 	protected Message(int id, MessageType type) {
 		this.id = id;
 		this.type = type;
 	}
 
+	/** Typically called by subclass when constructing outgoing message. */
 	protected Message(MessageType type) {
 		this(-1, type);
 	}
@@ -179,9 +85,9 @@ public abstract class Message {
 	/**
 	 * Attempt to read a message from byte buffer.
 	 * 
-	 * @param readOnlyBuffer
+	 * @param readOnlyBuffer ByteBuffer containing bytes read from network
 	 * @return null if no complete message can be read
-	 * @throws MessageException
+	 * @throws MessageException if message could not be decoded or is invalid
 	 */
 	public static Message fromByteBuffer(ByteBuffer readOnlyBuffer) throws MessageException {
 		try {
@@ -256,9 +162,27 @@ public abstract class Message {
 		return Arrays.copyOfRange(Crypto.digest(dataBuffer), 0, CHECKSUM_LENGTH);
 	}
 
+	public void checkValidOutgoing() throws MessageException {
+		// We expect subclass to have initialized these
+		if (this.dataBytes == null)
+			throw new MessageException("Missing data payload");
+		if (this.dataBytes.length > 0 && this.checksumBytes == null)
+			throw new MessageException("Missing data checksum");
+	}
+
 	public byte[] toBytes() throws MessageException {
+		checkValidOutgoing();
+
+		// We can calculate exact length
+		int messageLength = MAGIC_LENGTH + TYPE_LENGTH + HAS_ID_LENGTH;
+		messageLength += this.hasId() ? ID_LENGTH : 0;
+		messageLength += DATA_SIZE_LENGTH + this.dataBytes.length > 0 ? CHECKSUM_LENGTH + this.dataBytes.length : 0;
+
+		if (messageLength > MAX_DATA_SIZE)
+			throw new MessageException(String.format("About to send message with length %d larger than allowed %d", messageLength, MAX_DATA_SIZE));
+
 		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream(256);
+			ByteArrayOutputStream bytes = new ByteArrayOutputStream(messageLength);
 
 			// Magic
 			bytes.write(Network.getInstance().getMessageMagic());
@@ -273,26 +197,30 @@ public abstract class Message {
 				bytes.write(0);
 			}
 
-			byte[] data = this.toData();
-			if (data == null)
-				throw new MessageException("Missing data payload");
+			bytes.write(Ints.toByteArray(this.dataBytes.length));
 
-			bytes.write(Ints.toByteArray(data.length));
-
-			if (data.length > 0) {
-				bytes.write(generateChecksum(data));
-				bytes.write(data);
+			if (this.dataBytes.length > 0) {
+				bytes.write(this.checksumBytes);
+				bytes.write(this.dataBytes);
 			}
 
-			if (bytes.size() > MAX_DATA_SIZE)
-				throw new MessageException(String.format("About to send message with length %d larger than allowed %d", bytes.size(), MAX_DATA_SIZE));
-
 			return bytes.toByteArray();
-		} catch (IOException | TransformationException e) {
+		} catch (IOException e) {
 			throw new MessageException("Failed to serialize message", e);
 		}
 	}
 
-	protected abstract byte[] toData() throws IOException, TransformationException;
+	public static <M extends Message> M cloneWithNewId(M message, int newId) {
+		M clone;
+
+		try {
+			clone = (M) message.clone();
+		} catch (CloneNotSupportedException e) {
+			throw new UnsupportedOperationException("Message sub-class not cloneable");
+		}
+
+		clone.setId(newId);
+		return clone;
+	}
 
 }

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

@@ -0,0 +1,19 @@
+package org.qortal.network.message;
+
+@SuppressWarnings("serial")
+public class MessageException extends Exception {
+    public MessageException() {
+    }
+
+    public MessageException(String message) {
+        super(message);
+    }
+
+    public MessageException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public MessageException(Throwable cause) {
+        super(cause);
+    }
+}

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

@@ -0,0 +1,8 @@
+package org.qortal.network.message;
+
+import java.nio.ByteBuffer;
+
+@FunctionalInterface
+public interface MessageProducer {
+    Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws MessageException;
+}

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

@@ -0,0 +1,96 @@
+package org.qortal.network.message;
+
+import java.nio.BufferUnderflowException;
+import java.nio.ByteBuffer;
+import java.util.Map;
+
+import static java.util.Arrays.stream;
+import static java.util.stream.Collectors.toMap;
+
+public enum MessageType {
+    // Handshaking
+    HELLO(0, HelloMessage::fromByteBuffer),
+    GOODBYE(1, GoodbyeMessage::fromByteBuffer),
+    CHALLENGE(2, ChallengeMessage::fromByteBuffer),
+    RESPONSE(3, ResponseMessage::fromByteBuffer),
+
+    // Status / notifications
+    HEIGHT_V2(10, HeightV2Message::fromByteBuffer),
+    PING(11, PingMessage::fromByteBuffer),
+    PONG(12, PongMessage::fromByteBuffer),
+
+    // Requesting data
+    PEERS_V2(20, PeersV2Message::fromByteBuffer),
+    GET_PEERS(21, GetPeersMessage::fromByteBuffer),
+
+    TRANSACTION(30, TransactionMessage::fromByteBuffer),
+    GET_TRANSACTION(31, GetTransactionMessage::fromByteBuffer),
+
+    TRANSACTION_SIGNATURES(40, TransactionSignaturesMessage::fromByteBuffer),
+    GET_UNCONFIRMED_TRANSACTIONS(41, GetUnconfirmedTransactionsMessage::fromByteBuffer),
+
+    BLOCK(50, BlockMessage::fromByteBuffer),
+    GET_BLOCK(51, GetBlockMessage::fromByteBuffer),
+
+    SIGNATURES(60, SignaturesMessage::fromByteBuffer),
+    GET_SIGNATURES_V2(61, GetSignaturesV2Message::fromByteBuffer),
+
+    BLOCK_SUMMARIES(70, BlockSummariesMessage::fromByteBuffer),
+    GET_BLOCK_SUMMARIES(71, GetBlockSummariesMessage::fromByteBuffer),
+
+    ONLINE_ACCOUNTS(80, OnlineAccountsMessage::fromByteBuffer),
+    GET_ONLINE_ACCOUNTS(81, GetOnlineAccountsMessage::fromByteBuffer),
+    ONLINE_ACCOUNTS_V2(82, OnlineAccountsV2Message::fromByteBuffer),
+    GET_ONLINE_ACCOUNTS_V2(83, GetOnlineAccountsV2Message::fromByteBuffer),
+
+    ARBITRARY_DATA(90, ArbitraryDataMessage::fromByteBuffer),
+    GET_ARBITRARY_DATA(91, GetArbitraryDataMessage::fromByteBuffer),
+
+    BLOCKS(100, null), // unsupported
+    GET_BLOCKS(101, null), // unsupported
+
+    ARBITRARY_DATA_FILE(110, ArbitraryDataFileMessage::fromByteBuffer),
+    GET_ARBITRARY_DATA_FILE(111, GetArbitraryDataFileMessage::fromByteBuffer),
+
+    ARBITRARY_DATA_FILE_LIST(120, ArbitraryDataFileListMessage::fromByteBuffer),
+    GET_ARBITRARY_DATA_FILE_LIST(121, GetArbitraryDataFileListMessage::fromByteBuffer),
+
+    ARBITRARY_SIGNATURES(130, ArbitrarySignaturesMessage::fromByteBuffer),
+
+    TRADE_PRESENCES(140, TradePresencesMessage::fromByteBuffer),
+    GET_TRADE_PRESENCES(141, GetTradePresencesMessage::fromByteBuffer),
+
+    ARBITRARY_METADATA(150, ArbitraryMetadataMessage::fromByteBuffer),
+    GET_ARBITRARY_METADATA(151, GetArbitraryMetadataMessage::fromByteBuffer);
+
+    public final int value;
+    public final MessageProducer fromByteBufferMethod;
+
+    private static final Map<Integer, MessageType> map = stream(MessageType.values())
+            .collect(toMap(messageType -> messageType.value, messageType -> messageType));
+
+    MessageType(int value, MessageProducer fromByteBufferMethod) {
+        this.value = value;
+        this.fromByteBufferMethod = fromByteBufferMethod;
+    }
+
+    public static MessageType valueOf(int value) {
+        return map.get(value);
+    }
+
+    /**
+     * Attempt to read a message from byte buffer.
+     *
+     * @param id message ID or -1
+     * @param byteBuffer ByteBuffer source for message
+     * @return null if no complete message can be read
+     * @throws MessageException if message could not be decoded or is invalid
+     * @throws BufferUnderflowException if not enough bytes in buffer to read message
+     */
+    public Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws MessageException {
+        if (this.fromByteBufferMethod == null)
+            throw new MessageException("Message type " + this.name() + " unsupported");
+
+        return this.fromByteBufferMethod.fromByteBuffer(id, byteBuffer);
+    }
+}

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

@@ -2,7 +2,6 @@ package org.qortal.network.message;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.List;
@@ -20,7 +19,26 @@ public class OnlineAccountsMessage extends Message {
 	private List<OnlineAccountData> onlineAccounts;
 
 	public OnlineAccountsMessage(List<OnlineAccountData> onlineAccounts) {
-		this(-1, onlineAccounts);
+		super(MessageType.ONLINE_ACCOUNTS);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			bytes.write(Ints.toByteArray(onlineAccounts.size()));
+
+			for (OnlineAccountData onlineAccountData : onlineAccounts) {
+				bytes.write(Longs.toByteArray(onlineAccountData.getTimestamp()));
+
+				bytes.write(onlineAccountData.getSignature());
+
+				bytes.write(onlineAccountData.getPublicKey());
+			}
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private OnlineAccountsMessage(int id, List<OnlineAccountData> onlineAccounts) {
@@ -33,7 +51,7 @@ public class OnlineAccountsMessage extends Message {
 		return this.onlineAccounts;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
 		final int accountCount = bytes.getInt();
 
 		List<OnlineAccountData> onlineAccounts = new ArrayList<>(accountCount);
@@ -54,27 +72,4 @@ public class OnlineAccountsMessage extends Message {
 		return new OnlineAccountsMessage(id, onlineAccounts);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(Ints.toByteArray(this.onlineAccounts.size()));
-
-			for (int i = 0; i < this.onlineAccounts.size(); ++i) {
-				OnlineAccountData onlineAccountData = this.onlineAccounts.get(i);
-
-				bytes.write(Longs.toByteArray(onlineAccountData.getTimestamp()));
-
-				bytes.write(onlineAccountData.getSignature());
-
-				bytes.write(onlineAccountData.getPublicKey());
-			}
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

src/main/java/org/qortal/network/message/OnlineAccountsV2Message.java

@@ -7,13 +7,11 @@ import org.qortal.transform.Transformer;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.stream.Collectors;
 
 /**
  * For sending online accounts info to remote peer.
@@ -25,11 +23,52 @@ import java.util.stream.Collectors;
  * Also V2 only builds online accounts message once!
  */
 public class OnlineAccountsV2Message extends Message {
+
 	private List<OnlineAccountData> onlineAccounts;
-	private byte[] cachedData;
 
 	public OnlineAccountsV2Message(List<OnlineAccountData> onlineAccounts) {
-		this(-1, onlineAccounts);
+		super(MessageType.ONLINE_ACCOUNTS_V2);
+
+		// Shortcut in case we have no online accounts
+		if (onlineAccounts.isEmpty()) {
+			this.dataBytes = Ints.toByteArray(0);
+			this.checksumBytes = Message.generateChecksum(this.dataBytes);
+			return;
+		}
+
+		// How many of each timestamp
+		Map<Long, Integer> countByTimestamp = new HashMap<>();
+
+		for (OnlineAccountData onlineAccountData : onlineAccounts) {
+			Long timestamp = onlineAccountData.getTimestamp();
+			countByTimestamp.compute(timestamp, (k, v) -> v == null ? 1 : ++v);
+		}
+
+		// We should know exactly how many bytes to allocate now
+		int byteSize = countByTimestamp.size() * (Transformer.INT_LENGTH + Transformer.TIMESTAMP_LENGTH)
+				+ onlineAccounts.size() * (Transformer.SIGNATURE_LENGTH + Transformer.PUBLIC_KEY_LENGTH);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream(byteSize);
+
+		try {
+			for (long timestamp : countByTimestamp.keySet()) {
+				bytes.write(Ints.toByteArray(countByTimestamp.get(timestamp)));
+
+				bytes.write(Longs.toByteArray(timestamp));
+
+				for (OnlineAccountData onlineAccountData : onlineAccounts) {
+					if (onlineAccountData.getTimestamp() == timestamp) {
+						bytes.write(onlineAccountData.getSignature());
+						bytes.write(onlineAccountData.getPublicKey());
+					}
+				}
+			}
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private OnlineAccountsV2Message(int id, List<OnlineAccountData> onlineAccounts) {
@@ -42,7 +81,7 @@ public class OnlineAccountsV2Message extends Message {
 		return this.onlineAccounts;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws MessageException {
 		int accountCount = bytes.getInt();
 
 		List<OnlineAccountData> onlineAccounts = new ArrayList<>(accountCount);
@@ -71,54 +110,4 @@ public class OnlineAccountsV2Message extends Message {
 		return new OnlineAccountsV2Message(id, onlineAccounts);
 	}
 
-	@Override
-	protected synchronized byte[] toData() {
-		if (this.cachedData != null)
-			return this.cachedData;
-
-		// Shortcut in case we have no online accounts
-		if (this.onlineAccounts.isEmpty()) {
-			this.cachedData = Ints.toByteArray(0);
-			return this.cachedData;
-		}
-
-		// How many of each timestamp
-		Map<Long, Integer> countByTimestamp = new HashMap<>();
-
-		for (int i = 0; i < this.onlineAccounts.size(); ++i) {
-			OnlineAccountData onlineAccountData = this.onlineAccounts.get(i);
-			Long timestamp = onlineAccountData.getTimestamp();
-			countByTimestamp.compute(timestamp, (k, v) -> v == null ? 1 : ++v);
-		}
-
-		// We should know exactly how many bytes to allocate now
-		int byteSize = countByTimestamp.size() * (Transformer.INT_LENGTH + Transformer.TIMESTAMP_LENGTH)
-				+ this.onlineAccounts.size() * (Transformer.SIGNATURE_LENGTH + Transformer.PUBLIC_KEY_LENGTH);
-
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream(byteSize);
-
-			for (long timestamp : countByTimestamp.keySet()) {
-				bytes.write(Ints.toByteArray(countByTimestamp.get(timestamp)));
-
-				bytes.write(Longs.toByteArray(timestamp));
-
-				for (int i = 0; i < this.onlineAccounts.size(); ++i) {
-					OnlineAccountData onlineAccountData = this.onlineAccounts.get(i);
-
-					if (onlineAccountData.getTimestamp() == timestamp) {
-						bytes.write(onlineAccountData.getSignature());
-
-						bytes.write(onlineAccountData.getPublicKey());
-					}
-				}
-			}
-
-			this.cachedData = bytes.toByteArray();
-			return this.cachedData;
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

src/main/java/org/qortal/network/message/PeersV2Message.java

@@ -2,7 +2,6 @@ package org.qortal.network.message;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
@@ -19,7 +18,35 @@ public class PeersV2Message extends Message {
 	private List<PeerAddress> peerAddresses;
 
 	public PeersV2Message(List<PeerAddress> peerAddresses) {
-		this(-1, peerAddresses);
+		super(MessageType.PEERS_V2);
+
+		List<byte[]> addresses = new ArrayList<>();
+
+		// First entry represents sending node but contains only port number with empty address.
+		addresses.add(("0.0.0.0:" + Settings.getInstance().getListenPort()).getBytes(StandardCharsets.UTF_8));
+
+		for (PeerAddress peerAddress : peerAddresses)
+			addresses.add(peerAddress.toString().getBytes(StandardCharsets.UTF_8));
+
+		// We can't send addresses that are longer than 255 bytes as length itself is encoded in one byte.
+		addresses.removeIf(addressString -> addressString.length > 255);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			// Number of entries
+			bytes.write(Ints.toByteArray(addresses.size()));
+
+			for (byte[] address : addresses) {
+				bytes.write(address.length);
+				bytes.write(address);
+			}
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private PeersV2Message(int id, List<PeerAddress> peerAddresses) {
@@ -32,7 +59,7 @@ public class PeersV2Message extends Message {
 		return this.peerAddresses;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws UnsupportedEncodingException {
+	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws MessageException {
 		// Read entry count
 		int count = byteBuffer.getInt();
 
@@ -49,43 +76,11 @@ public class PeersV2Message extends Message {
 				PeerAddress peerAddress = PeerAddress.fromString(addressString);
 				peerAddresses.add(peerAddress);
 			} catch (IllegalArgumentException e) {
-				// Not valid - ignore
+				throw new MessageException("Invalid peer address in received PEERS_V2 message");
 			}
 		}
 
 		return new PeersV2Message(id, peerAddresses);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			List<byte[]> addresses = new ArrayList<>();
-
-			// First entry represents sending node but contains only port number with empty address.
-			addresses.add(("0.0.0.0:" + Settings.getInstance().getListenPort()).getBytes(StandardCharsets.UTF_8));
-
-			for (PeerAddress peerAddress : this.peerAddresses)
-				addresses.add(peerAddress.toString().getBytes(StandardCharsets.UTF_8));
-
-			// We can't send addresses that are longer than 255 bytes as length itself is encoded in one byte.
-			addresses.removeIf(addressString -> addressString.length > 255);
-
-			// Serialize
-
-			// Number of entries
-			bytes.write(Ints.toByteArray(addresses.size()));
-
-			for (byte[] address : addresses) {
-				bytes.write(address.length);
-				bytes.write(address);
-			}
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

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

@@ -1,25 +1,21 @@
 package org.qortal.network.message;
 
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 
 public class PingMessage extends Message {
 
 	public PingMessage() {
-		this(-1);
+		super(MessageType.PING);
+
+		this.dataBytes = EMPTY_DATA_BYTES;
 	}
 
 	private PingMessage(int id) {
 		super(id, MessageType.PING);
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
 		return new PingMessage(id);
 	}
 
-	@Override
-	protected byte[] toData() {
-		return new byte[0];
-	}
-
 }

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

@@ -0,0 +1,21 @@
+package org.qortal.network.message;
+
+import java.nio.ByteBuffer;
+
+public class PongMessage extends Message {
+
+	public PongMessage() {
+		super(MessageType.PONG);
+
+		this.dataBytes = EMPTY_DATA_BYTES;
+	}
+
+	private PongMessage(int id) {
+		super(id, MessageType.PONG);
+	}
+
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
+		return new PongMessage(id);
+	}
+
+}

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

@@ -10,8 +10,25 @@ public class ResponseMessage extends Message {
 
 	public static final int DATA_LENGTH = 32;
 
-	private final int nonce;
-	private final byte[] data;
+	private int nonce;
+	private byte[] data;
+
+	public ResponseMessage(int nonce, byte[] data) {
+		super(MessageType.RESPONSE);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream(4 + DATA_LENGTH);
+
+		try {
+			bytes.write(Ints.toByteArray(nonce));
+
+			bytes.write(data);
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
+	}
 
 	private ResponseMessage(int id, int nonce, byte[] data) {
 		super(id, MessageType.RESPONSE);
@@ -20,10 +37,6 @@ public class ResponseMessage extends Message {
 		this.data = data;
 	}
 
-	public ResponseMessage(int nonce, byte[] data) {
-		this(-1, nonce, data);
-	}
-
 	public int getNonce() {
 		return this.nonce;
 	}
@@ -41,15 +54,4 @@ public class ResponseMessage extends Message {
 		return new ResponseMessage(id, nonce, data);
 	}
 
-	@Override
-	protected byte[] toData() throws IOException {
-		ByteArrayOutputStream bytes = new ByteArrayOutputStream(4 + DATA_LENGTH);
-
-		bytes.write(Ints.toByteArray(this.nonce));
-
-		bytes.write(data);
-
-		return bytes.toByteArray();
-	}
-
 }

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

@@ -2,7 +2,7 @@ package org.qortal.network.message;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
+import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.List;
@@ -13,12 +13,24 @@ import com.google.common.primitives.Ints;
 
 public class SignaturesMessage extends Message {
 
-	private static final int BLOCK_SIGNATURE_LENGTH = BlockTransformer.BLOCK_SIGNATURE_LENGTH;
-
 	private List<byte[]> signatures;
 
 	public SignaturesMessage(List<byte[]> signatures) {
-		this(-1, signatures);
+		super(MessageType.SIGNATURES);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			bytes.write(Ints.toByteArray(signatures.size()));
+
+			for (byte[] signature : signatures)
+				bytes.write(signature);
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private SignaturesMessage(int id, List<byte[]> signatures) {
@@ -31,15 +43,15 @@ public class SignaturesMessage extends Message {
 		return this.signatures;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
 		int count = bytes.getInt();
 
-		if (bytes.remaining() != count * BLOCK_SIGNATURE_LENGTH)
-			return null;
+		if (bytes.remaining() < count * BlockTransformer.BLOCK_SIGNATURE_LENGTH)
+			throw new BufferUnderflowException();
 
 		List<byte[]> signatures = new ArrayList<>();
 		for (int i = 0; i < count; ++i) {
-			byte[] signature = new byte[BLOCK_SIGNATURE_LENGTH];
+			byte[] signature = new byte[BlockTransformer.BLOCK_SIGNATURE_LENGTH];
 			bytes.get(signature);
 			signatures.add(signature);
 		}
@@ -47,20 +59,4 @@ public class SignaturesMessage extends Message {
 		return new SignaturesMessage(id, signatures);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(Ints.toByteArray(this.signatures.size()));
-
-			for (byte[] signature : this.signatures)
-				bytes.write(signature);
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

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

@@ -8,7 +8,6 @@ import org.qortal.utils.Base58;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -21,11 +20,55 @@ import java.util.Map;
  * Groups of: number of entries, timestamp, then pubkey + sig + AT address for each entry.
  */
 public class TradePresencesMessage extends Message {
+
 	private List<TradePresenceData> tradePresences;
-	private byte[] cachedData;
 
 	public TradePresencesMessage(List<TradePresenceData> tradePresences) {
-		this(-1, tradePresences);
+		super(MessageType.TRADE_PRESENCES);
+
+		// Shortcut in case we have no trade presences
+		if (tradePresences.isEmpty()) {
+			this.dataBytes = Ints.toByteArray(0);
+			this.checksumBytes = Message.generateChecksum(this.dataBytes);
+			return;
+		}
+
+		// How many of each timestamp
+		Map<Long, Integer> countByTimestamp = new HashMap<>();
+
+		for (TradePresenceData tradePresenceData : tradePresences) {
+			Long timestamp = tradePresenceData.getTimestamp();
+			countByTimestamp.compute(timestamp, (k, v) -> v == null ? 1 : ++v);
+		}
+
+		// We should know exactly how many bytes to allocate now
+		int byteSize = countByTimestamp.size() * (Transformer.INT_LENGTH + Transformer.TIMESTAMP_LENGTH)
+				+ tradePresences.size() * (Transformer.PUBLIC_KEY_LENGTH + Transformer.SIGNATURE_LENGTH + Transformer.ADDRESS_LENGTH);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream(byteSize);
+
+		try {
+			for (long timestamp : countByTimestamp.keySet()) {
+				bytes.write(Ints.toByteArray(countByTimestamp.get(timestamp)));
+
+				bytes.write(Longs.toByteArray(timestamp));
+
+				for (TradePresenceData tradePresenceData : tradePresences) {
+					if (tradePresenceData.getTimestamp() == timestamp) {
+						bytes.write(tradePresenceData.getPublicKey());
+
+						bytes.write(tradePresenceData.getSignature());
+
+						bytes.write(Base58.decode(tradePresenceData.getAtAddress()));
+					}
+				}
+			}
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private TradePresencesMessage(int id, List<TradePresenceData> tradePresences) {
@@ -38,7 +81,7 @@ public class TradePresencesMessage extends Message {
 		return this.tradePresences;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
 		int groupedEntriesCount = bytes.getInt();
 
 		List<TradePresenceData> tradePresences = new ArrayList<>(groupedEntriesCount);
@@ -71,53 +114,4 @@ public class TradePresencesMessage extends Message {
 		return new TradePresencesMessage(id, tradePresences);
 	}
 
-	@Override
-	protected synchronized byte[] toData() {
-		if (this.cachedData != null)
-			return this.cachedData;
-
-		// Shortcut in case we have no trade presences
-		if (this.tradePresences.isEmpty()) {
-			this.cachedData = Ints.toByteArray(0);
-			return this.cachedData;
-		}
-
-		// How many of each timestamp
-		Map<Long, Integer> countByTimestamp = new HashMap<>();
-
-		for (TradePresenceData tradePresenceData : this.tradePresences) {
-			Long timestamp = tradePresenceData.getTimestamp();
-			countByTimestamp.compute(timestamp, (k, v) -> v == null ? 1 : ++v);
-		}
-
-		// We should know exactly how many bytes to allocate now
-		int byteSize = countByTimestamp.size() * (Transformer.INT_LENGTH + Transformer.TIMESTAMP_LENGTH)
-				+ this.tradePresences.size() * (Transformer.PUBLIC_KEY_LENGTH + Transformer.SIGNATURE_LENGTH + Transformer.ADDRESS_LENGTH);
-
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream(byteSize);
-
-			for (long timestamp : countByTimestamp.keySet()) {
-				bytes.write(Ints.toByteArray(countByTimestamp.get(timestamp)));
-
-				bytes.write(Longs.toByteArray(timestamp));
-
-				for (TradePresenceData tradePresenceData : this.tradePresences) {
-					if (tradePresenceData.getTimestamp() == timestamp) {
-						bytes.write(tradePresenceData.getPublicKey());
-
-						bytes.write(tradePresenceData.getSignature());
-
-						bytes.write(Base58.decode(tradePresenceData.getAtAddress()));
-					}
-				}
-			}
-
-			this.cachedData = bytes.toByteArray();
-			return this.cachedData;
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

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

@@ -1,6 +1,5 @@
 package org.qortal.network.message;
 
-import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 
 import org.qortal.data.transaction.TransactionData;
@@ -11,8 +10,11 @@ public class TransactionMessage extends Message {
 
 	private TransactionData transactionData;
 
-	public TransactionMessage(TransactionData transactionData) {
-		this(-1, transactionData);
+	public TransactionMessage(TransactionData transactionData) throws TransformationException {
+		super(MessageType.TRANSACTION);
+
+		this.dataBytes = TransactionTransformer.toBytes(transactionData);
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private TransactionMessage(int id, TransactionData transactionData) {
@@ -25,26 +27,16 @@ public class TransactionMessage extends Message {
 		return this.transactionData;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws UnsupportedEncodingException {
-		try {
-			TransactionData transactionData = TransactionTransformer.fromByteBuffer(byteBuffer);
-
-			return new TransactionMessage(id, transactionData);
-		} catch (TransformationException e) {
-			return null;
-		}
-	}
-
-	@Override
-	protected byte[] toData() {
-		if (this.transactionData == null)
-			return null;
+	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws MessageException {
+		TransactionData transactionData;
 
 		try {
-			return TransactionTransformer.toBytes(this.transactionData);
+			transactionData = TransactionTransformer.fromByteBuffer(byteBuffer);
 		} catch (TransformationException e) {
-			return null;
+			throw new MessageException(e.getMessage(), e);
 		}
+
+		return new TransactionMessage(id, transactionData);
 	}
 
 }

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

@@ -2,7 +2,7 @@ package org.qortal.network.message;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
+import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.List;
@@ -13,12 +13,24 @@ import com.google.common.primitives.Ints;
 
 public class TransactionSignaturesMessage extends Message {
 
-	private static final int SIGNATURE_LENGTH = Transformer.SIGNATURE_LENGTH;
-
 	private List<byte[]> signatures;
 
 	public TransactionSignaturesMessage(List<byte[]> signatures) {
-		this(-1, signatures);
+		super(MessageType.TRANSACTION_SIGNATURES);
+
+		ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+		try {
+			bytes.write(Ints.toByteArray(signatures.size()));
+
+			for (byte[] signature : signatures)
+				bytes.write(signature);
+		} catch (IOException e) {
+			throw new AssertionError("IOException shouldn't occur with ByteArrayOutputStream");
+		}
+
+		this.dataBytes = bytes.toByteArray();
+		this.checksumBytes = Message.generateChecksum(this.dataBytes);
 	}
 
 	private TransactionSignaturesMessage(int id, List<byte[]> signatures) {
@@ -31,15 +43,15 @@ public class TransactionSignaturesMessage extends Message {
 		return this.signatures;
 	}
 
-	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) {
 		int count = bytes.getInt();
 
-		if (bytes.remaining() != count * SIGNATURE_LENGTH)
-			return null;
+		if (bytes.remaining() < count * Transformer.SIGNATURE_LENGTH)
+			throw new BufferUnderflowException();
 
 		List<byte[]> signatures = new ArrayList<>();
 		for (int i = 0; i < count; ++i) {
-			byte[] signature = new byte[SIGNATURE_LENGTH];
+			byte[] signature = new byte[Transformer.SIGNATURE_LENGTH];
 			bytes.get(signature);
 			signatures.add(signature);
 		}
@@ -47,20 +59,4 @@ public class TransactionSignaturesMessage extends Message {
 		return new TransactionSignaturesMessage(id, signatures);
 	}
 
-	@Override
-	protected byte[] toData() {
-		try {
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-
-			bytes.write(Ints.toByteArray(this.signatures.size()));
-
-			for (byte[] signature : this.signatures)
-				bytes.write(signature);
-
-			return bytes.toByteArray();
-		} catch (IOException e) {
-			return null;
-		}
-	}
-
 }

src/main/java/org/qortal/network/task/BroadcastTask.java

@@ -0,0 +1,22 @@
+package org.qortal.network.task;
+
+import org.qortal.controller.Controller;
+import org.qortal.network.Network;
+import org.qortal.network.Peer;
+import org.qortal.network.message.Message;
+import org.qortal.utils.ExecuteProduceConsume.Task;
+
+public class BroadcastTask implements Task {
+    public BroadcastTask() {
+    }
+
+    @Override
+    public String getName() {
+        return "BroadcastTask";
+    }
+
+    @Override
+    public void perform() throws InterruptedException {
+        Controller.getInstance().doNetworkBroadcast();
+    }
+}

src/main/java/org/qortal/network/task/ChannelAcceptTask.java

@@ -0,0 +1,143 @@
+package org.qortal.network.task;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.controller.arbitrary.ArbitraryDataFileManager;
+import org.qortal.network.Network;
+import org.qortal.network.Peer;
+import org.qortal.network.PeerAddress;
+import org.qortal.settings.Settings;
+import org.qortal.utils.ExecuteProduceConsume.Task;
+import org.qortal.utils.NTP;
+
+import java.io.IOException;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.ServerSocketChannel;
+import java.nio.channels.SocketChannel;
+import java.util.List;
+
+public class ChannelAcceptTask implements Task {
+    private static final Logger LOGGER = LogManager.getLogger(ChannelAcceptTask.class);
+
+    private final ServerSocketChannel serverSocketChannel;
+
+    public ChannelAcceptTask(ServerSocketChannel serverSocketChannel) {
+        this.serverSocketChannel = serverSocketChannel;
+    }
+
+    @Override
+    public String getName() {
+        return "ChannelAcceptTask";
+    }
+
+    @Override
+    public void perform() throws InterruptedException {
+        Network network = Network.getInstance();
+        SocketChannel socketChannel;
+
+        try {
+            if (network.getImmutableConnectedPeers().size() >= network.getMaxPeers()) {
+                // We have enough peers
+                LOGGER.debug("Ignoring pending incoming connections because the server is full");
+                return;
+            }
+
+            socketChannel = serverSocketChannel.accept();
+
+            network.setInterestOps(serverSocketChannel, SelectionKey.OP_ACCEPT);
+        } catch (IOException e) {
+            return;
+        }
+
+        // No connection actually accepted?
+        if (socketChannel == null) {
+            return;
+        }
+
+        PeerAddress address = PeerAddress.fromSocket(socketChannel.socket());
+        List<String> fixedNetwork = Settings.getInstance().getFixedNetwork();
+        if (fixedNetwork != null && !fixedNetwork.isEmpty() && network.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;
+        }
+
+        // We allow up to a maximum of maxPeers connected peers, of which...
+        // - maxDataPeers must be prearranged data connections (these are intentionally short-lived)
+        // - the remainder can be any regular peers
+
+        // Firstly, determine the maximum limits
+        int maxPeers = Settings.getInstance().getMaxPeers();
+        int maxDataPeers = Settings.getInstance().getMaxDataPeers();
+        int maxRegularPeers = maxPeers - maxDataPeers;
+
+        // Next, obtain the current state
+        int connectedDataPeerCount = Network.getInstance().getImmutableConnectedDataPeers().size();
+        int connectedRegularPeerCount = Network.getInstance().getImmutableConnectedNonDataPeers().size();
+
+        // Check if the incoming connection should be considered a data or regular peer
+        boolean isDataPeer = ArbitraryDataFileManager.getInstance().isPeerRequestingData(address.getHost());
+
+        // Finally, decide if we have any capacity for this incoming peer
+        boolean connectionLimitReached;
+        if (isDataPeer) {
+            connectionLimitReached = (connectedDataPeerCount >= maxDataPeers);
+        }
+        else {
+            connectionLimitReached = (connectedRegularPeerCount >= maxRegularPeers);
+        }
+
+        // Extra maxPeers check just to be safe
+        if (Network.getInstance().getImmutableConnectedPeers().size() >= maxPeers) {
+            connectionLimitReached = true;
+        }
+
+        if (connectionLimitReached) {
+            try {
+                // We have enough peers
+                LOGGER.debug("Connection discarded from peer {} because the server is full", 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", address);
+                socketChannel.close();
+                return;
+            }
+
+            LOGGER.debug("Connection accepted from peer {}", address);
+
+            newPeer = new Peer(socketChannel);
+            if (isDataPeer) {
+                newPeer.setMaxConnectionAge(Settings.getInstance().getMaxDataPeerConnectionTime() * 1000L);
+            }
+            newPeer.setIsDataPeer(isDataPeer);
+            network.addConnectedPeer(newPeer);
+
+        } 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?
+                }
+            }
+            return;
+        }
+
+        network.onPeerReady(newPeer);
+    }
+}

src/main/java/org/qortal/network/task/ChannelReadTask.java

@@ -0,0 +1,49 @@
+package org.qortal.network.task;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import org.qortal.network.Network;
+import org.qortal.network.Peer;
+import org.qortal.utils.ExecuteProduceConsume.Task;
+
+import java.io.IOException;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.SocketChannel;
+
+public class ChannelReadTask implements Task {
+    private static final Logger LOGGER = LogManager.getLogger(ChannelReadTask.class);
+
+    private final SocketChannel socketChannel;
+    private final Peer peer;
+    private final String name;
+
+    public ChannelReadTask(SocketChannel socketChannel, Peer peer) {
+        this.socketChannel = socketChannel;
+        this.peer = peer;
+        this.name = "ChannelReadTask::" + peer;
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public void perform() throws InterruptedException {
+        try {
+            peer.readChannel();
+
+            Network.getInstance().setInterestOps(socketChannel, SelectionKey.OP_READ);
+        } catch (IOException e) {
+            if (e.getMessage() != null && e.getMessage().toLowerCase().contains("connection reset")) {
+                peer.disconnect("Connection reset");
+                return;
+            }
+
+            LOGGER.trace("[{}] Network thread {} encountered I/O error: {}", peer.getPeerConnectionId(),
+                    Thread.currentThread().getId(), e.getMessage(), e);
+            peer.disconnect("I/O error");
+        }
+    }
+}

src/main/java/org/qortal/network/task/ChannelWriteTask.java

@@ -0,0 +1,52 @@
+package org.qortal.network.task;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.network.Network;
+import org.qortal.network.Peer;
+import org.qortal.utils.ExecuteProduceConsume.Task;
+
+import java.io.IOException;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.SocketChannel;
+
+public class ChannelWriteTask implements Task {
+    private static final Logger LOGGER = LogManager.getLogger(ChannelWriteTask.class);
+
+    private final SocketChannel socketChannel;
+    private final Peer peer;
+    private final String name;
+
+    public ChannelWriteTask(SocketChannel socketChannel, Peer peer) {
+        this.socketChannel = socketChannel;
+        this.peer = peer;
+        this.name = "ChannelWriteTask::" + peer;
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public void perform() throws InterruptedException {
+        try {
+            boolean isSocketClogged = peer.writeChannel();
+
+            // Tell Network that we've finished
+            Network.getInstance().notifyChannelNotWriting(socketChannel);
+
+            if (isSocketClogged)
+                Network.getInstance().setInterestOps(this.socketChannel, SelectionKey.OP_WRITE);
+        } catch (IOException e) {
+            if (e.getMessage() != null && e.getMessage().toLowerCase().contains("connection reset")) {
+                peer.disconnect("Connection reset");
+                return;
+            }
+
+            LOGGER.trace("[{}] Network thread {} encountered I/O error: {}", peer.getPeerConnectionId(),
+                    Thread.currentThread().getId(), e.getMessage(), e);
+            peer.disconnect("I/O error");
+        }
+    }
+}

src/main/java/org/qortal/network/task/MessageTask.java

@@ -0,0 +1,28 @@
+package org.qortal.network.task;
+
+import org.qortal.network.Network;
+import org.qortal.network.Peer;
+import org.qortal.network.message.Message;
+import org.qortal.utils.ExecuteProduceConsume.Task;
+
+public class MessageTask implements Task {
+    private final Peer peer;
+    private final Message nextMessage;
+    private final String name;
+
+    public MessageTask(Peer peer, Message nextMessage) {
+        this.peer = peer;
+        this.nextMessage = nextMessage;
+        this.name = "MessageTask::" + peer + "::" + nextMessage.getType();
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public void perform() throws InterruptedException {
+        Network.getInstance().onMessage(peer, nextMessage);
+    }
+}

src/main/java/org/qortal/network/task/PeerConnectTask.java

@@ -0,0 +1,33 @@
+package org.qortal.network.task;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.network.Network;
+import org.qortal.network.Peer;
+import org.qortal.network.message.Message;
+import org.qortal.network.message.MessageType;
+import org.qortal.network.message.PingMessage;
+import org.qortal.utils.ExecuteProduceConsume.Task;
+import org.qortal.utils.NTP;
+
+public class PeerConnectTask implements Task {
+    private static final Logger LOGGER = LogManager.getLogger(PeerConnectTask.class);
+
+    private final Peer peer;
+    private final String name;
+
+    public PeerConnectTask(Peer peer) {
+        this.peer = peer;
+        this.name = "PeerConnectTask::" + peer;
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public void perform() throws InterruptedException {
+        Network.getInstance().connectPeer(peer);
+    }
+}

src/main/java/org/qortal/network/task/PingTask.java

@@ -0,0 +1,44 @@
+package org.qortal.network.task;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.network.Peer;
+import org.qortal.network.message.Message;
+import org.qortal.network.message.MessageType;
+import org.qortal.network.message.PingMessage;
+import org.qortal.utils.ExecuteProduceConsume.Task;
+import org.qortal.utils.NTP;
+
+public class PingTask implements Task {
+    private static final Logger LOGGER = LogManager.getLogger(PingTask.class);
+
+    private final Peer peer;
+    private final Long now;
+    private final String name;
+
+    public PingTask(Peer peer, Long now) {
+        this.peer = peer;
+        this.now = now;
+        this.name = "PingTask::" + peer;
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public void perform() throws InterruptedException {
+        PingMessage pingMessage = new PingMessage();
+        Message message = peer.getResponse(pingMessage);
+
+        if (message == null || message.getType() != MessageType.PING) {
+            LOGGER.debug("[{}] Didn't receive reply from {} for PING ID {}",
+                    peer.getPeerConnectionId(), peer, pingMessage.getId());
+            peer.disconnect("no ping received");
+            return;
+        }
+
+        peer.setLastPing(NTP.getTime() - now);
+    }
+}

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

@@ -76,6 +76,9 @@ public interface AccountRepository {
 	 */
 	public void setBlocksMintedAdjustment(AccountData accountData) throws DataException;
 
+	/** Returns account's minted block count or null if account not found. */
+	public Integer getMintedBlockCount(String address) throws DataException;
+
 	/**
 	 * Saves account's minted block count and public key if present, in repository.
 	 * <p>

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

@@ -419,8 +419,8 @@ public class Bootstrap {
                 downloaded += bytesRead;
 
                 if (fileSize > 0) {
-                    int progress = (int)((double)downloaded / (double)fileSize * 100);
-                    SplashFrame.getInstance().updateStatus(String.format("Downloading %s bootstrap... (%d%%)", type, progress));
+                    double progress = (double)downloaded / (double)fileSize * 100;
+                    SplashFrame.getInstance().updateStatus(String.format("Downloading %s bootstrap... (%.1f%%)", type, progress));
                 }
             }
 

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

@@ -241,6 +241,20 @@ public class HSQLDBAccountRepository implements AccountRepository {
 		}
 	}
 
+	@Override
+	public Integer getMintedBlockCount(String address) throws DataException {
+		String sql = "SELECT blocks_minted FROM Accounts WHERE account = ?";
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql, address)) {
+			if (resultSet == null)
+				return null;
+
+			return resultSet.getInt(1);
+		} catch (SQLException e) {
+			throw new DataException("Unable to fetch account's minted block count from repository", e);
+		}
+	}
+
 	@Override
 	public void setMintedBlockCount(AccountData accountData) throws DataException {
 		HSQLDBSaver saveHelper = new HSQLDBSaver("Accounts");

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

@@ -188,7 +188,9 @@ public class Settings {
 	/** Target number of outbound connections to peers we should make. */
 	private int minOutboundPeers = 16;
 	/** Maximum number of peer connections we allow. */
-	private int maxPeers = 32;
+	private int maxPeers = 36;
+	/** Number of slots to reserve for short-lived QDN data transfers */
+	private int maxDataPeers = 4;
 	/** Maximum number of threads for network engine. */
 	private int maxNetworkThreadPoolSize = 32;
 	/** Maximum number of threads for network proof-of-work compute, used during handshaking. */
@@ -207,6 +209,8 @@ public class Settings {
 	private int minPeerConnectionTime = 5 * 60; // seconds
 	/** Maximum time (in seconds) that we should attempt to remain connected to a peer for */
 	private int maxPeerConnectionTime = 60 * 60; // seconds
+	/** Maximum time (in seconds) that a peer should remain connected when requesting QDN data */
+	private int maxDataPeerConnectionTime = 2 * 60; // seconds
 
 	/** Whether to sync multiple blocks at once in normal operation */
 	private boolean fastSyncEnabled = true;
@@ -646,6 +650,10 @@ public class Settings {
 		return this.maxPeers;
 	}
 
+	public int getMaxDataPeers() {
+		return this.maxDataPeers;
+	}
+
 	public int getMaxNetworkThreadPoolSize() {
 		return this.maxNetworkThreadPoolSize;
 	}
@@ -664,6 +672,10 @@ public class Settings {
 
 	public int getMaxPeerConnectionTime() { return this.maxPeerConnectionTime; }
 
+	public int getMaxDataPeerConnectionTime() {
+		return this.maxDataPeerConnectionTime;
+	}
+
 	public String getBlockchainConfig() {
 		return this.blockchainConfig;
 	}

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

@@ -29,7 +29,7 @@ public class ChatTransaction extends Transaction {
 	public static final int MAX_DATA_SIZE = 256;
 	public static final int POW_BUFFER_SIZE = 8 * 1024 * 1024; // bytes
 	public static final int POW_DIFFICULTY_WITH_QORT = 8; // leading zero bits
-	public static final int POW_DIFFICULTY_NO_QORT = 14; // leading zero bits
+	public static final int POW_DIFFICULTY_NO_QORT = 12; // leading zero bits
 
 	// Constructors
 

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

@@ -185,7 +185,7 @@ public class PresenceTransaction extends Transaction {
 		String signerAddress = Crypto.toAddress(this.transactionData.getCreatorPublicKey());
 
 		for (ATData atData : atsData) {
-			ByteArray atCodeHash = new ByteArray(atData.getCodeHash());
+			ByteArray atCodeHash = ByteArray.wrap(atData.getCodeHash());
 			Supplier<ACCT> acctSupplier = acctSuppliersByCodeHash.get(atCodeHash);
 			if (acctSupplier == null)
 				continue;

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

@@ -39,11 +39,7 @@ public class RegisterNameTransaction extends Transaction {
 
 	@Override
 	public long getUnitFee(Long timestamp) {
-		// Use a higher unit fee after the fee increase timestamp
-		if (timestamp > BlockChain.getInstance().getNameRegistrationUnitFeeTimestamp()) {
-			return BlockChain.getInstance().getNameRegistrationUnitFee();
-		}
-		return BlockChain.getInstance().getUnitFee();
+		return BlockChain.getInstance().getNameRegistrationUnitFeeAtTimestamp(timestamp);
 	}
 
 	// Navigation

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

@@ -118,10 +118,13 @@ public class UpdateNameTransaction extends Transaction {
 		if (!owner.getAddress().equals(nameData.getOwner()))
 			return ValidationResult.INVALID_NAME_OWNER;
 
-		// Check new name isn't already taken, unless it is the same name (this allows for case-adjusting renames)
-		NameData newNameData = this.repository.getNameRepository().fromReducedName(this.updateNameTransactionData.getReducedNewName());
-		if (newNameData != null && !newNameData.getName().equals(nameData.getName()))
-			return ValidationResult.NAME_ALREADY_REGISTERED;
+		// Additional checks if transaction intends to change name
+		if (!this.updateNameTransactionData.getNewName().isEmpty()) {
+			// Check new name isn't already taken, unless it is the same name (this allows for case-adjusting renames)
+			NameData newNameData = this.repository.getNameRepository().fromReducedName(this.updateNameTransactionData.getReducedNewName());
+			if (newNameData != null && !newNameData.getName().equals(nameData.getName()))
+				return ValidationResult.NAME_ALREADY_REGISTERED;
+		}
 
 		return ValidationResult.OK;
 	}

src/main/java/org/qortal/transform/transaction/ArbitraryTransactionTransformer.java

@@ -39,12 +39,12 @@ public class ArbitraryTransactionTransformer extends TransactionTransformer {
 	private static final int IDENTIFIER_SIZE_LENGTH = INT_LENGTH;
 	private static final int COMPRESSION_LENGTH = INT_LENGTH;
 	private static final int METHOD_LENGTH = INT_LENGTH;
-	private static final int SECRET_LENGTH = INT_LENGTH; // TODO: wtf?
+	private static final int SECRET_SIZE_LENGTH = INT_LENGTH;
 
 	private static final int EXTRAS_LENGTH = SERVICE_LENGTH + DATA_TYPE_LENGTH + DATA_SIZE_LENGTH;
 
 	private static final int EXTRAS_V5_LENGTH = NONCE_LENGTH + NAME_SIZE_LENGTH + IDENTIFIER_SIZE_LENGTH +
-			METHOD_LENGTH + SECRET_LENGTH + COMPRESSION_LENGTH + RAW_DATA_SIZE_LENGTH + METADATA_HASH_SIZE_LENGTH;
+			METHOD_LENGTH + SECRET_SIZE_LENGTH + COMPRESSION_LENGTH + RAW_DATA_SIZE_LENGTH + METADATA_HASH_SIZE_LENGTH;
 
 	protected static final TransactionLayout layout;
 

src/main/java/org/qortal/utils/ByteArray.java

@@ -8,12 +8,16 @@ public class ByteArray implements Comparable<ByteArray> {
 	private int hash;
 	public final byte[] value;
 
-	public ByteArray(byte[] value) {
-		this.value = Objects.requireNonNull(value);
+	private ByteArray(byte[] value) {
+		this.value = value;
 	}
 
-	public static ByteArray of(byte[] value) {
-		return new ByteArray(value);
+	public static ByteArray wrap(byte[] value) {
+		return new ByteArray(Objects.requireNonNull(value));
+	}
+
+	public static ByteArray copyOf(byte[] value) {
+		return new ByteArray(Arrays.copyOf(value, value.length));
 	}
 
 	@Override
@@ -36,12 +40,7 @@ public class ByteArray implements Comparable<ByteArray> {
 		byte[] val = this.value;
 
 		if (h == 0 && val.length > 0) {
-			h = 1;
-
-			for (int i = 0; i < val.length; ++i)
-				h = 31 * h + val[i];
-
-			this.hash = h;
+			this.hash = h = Arrays.hashCode(val);
 		}
 		return h;
 	}
@@ -53,24 +52,7 @@ public class ByteArray implements Comparable<ByteArray> {
 	}
 
 	public int compareToPrimitive(byte[] otherValue) {
-		byte[] val = this.value;
-
-		if (val.length < otherValue.length)
-			return -1;
-
-		if (val.length > otherValue.length)
-			return 1;
-
-		for (int i = 0; i < val.length; ++i) {
-			int a = val[i] & 0xFF;
-			int b = otherValue[i] & 0xFF;
-			if (a < b)
-				return -1;
-			if (a > b)
-				return 1;
-		}
-
-		return 0;
+		return Arrays.compareUnsigned(this.value, otherValue);
 	}
 
 	public String toString() {

src/main/java/org/qortal/utils/ExecuteProduceConsume.java

@@ -28,7 +28,6 @@ public abstract class ExecuteProduceConsume implements Runnable {
 
 	private final String className;
 	private final Logger logger;
-	private final boolean isLoggerTraceEnabled;
 
 	protected ExecutorService executor;
 
@@ -43,12 +42,12 @@ public abstract class ExecuteProduceConsume implements Runnable {
 	private volatile int tasksConsumed = 0;
 	private volatile int spawnFailures = 0;
 
+	/** Whether a new thread has already been spawned and is waiting to start. Used to prevent spawning multiple new threads. */
 	private volatile boolean hasThreadPending = false;
 
 	public ExecuteProduceConsume(ExecutorService executor) {
 		this.className = this.getClass().getSimpleName();
 		this.logger = LogManager.getLogger(this.getClass());
-		this.isLoggerTraceEnabled = this.logger.isTraceEnabled();
 
 		this.executor = executor;
 	}
@@ -98,15 +97,14 @@ public abstract class ExecuteProduceConsume implements Runnable {
 	 */
 	protected abstract Task produceTask(boolean canBlock) throws InterruptedException;
 
-	@FunctionalInterface
 	public interface Task {
-		public abstract void perform() throws InterruptedException;
+		String getName();
+		void perform() throws InterruptedException;
 	}
 
 	@Override
 	public void run() {
-		if (this.isLoggerTraceEnabled)
-			Thread.currentThread().setName(this.className + "-" + Thread.currentThread().getId());
+		Thread.currentThread().setName(this.className + "-" + Thread.currentThread().getId());
 
 		boolean wasThreadPending;
 		synchronized (this) {
@@ -114,25 +112,19 @@ public abstract class ExecuteProduceConsume implements Runnable {
 			if (this.activeThreadCount > this.greatestActiveThreadCount)
 				this.greatestActiveThreadCount = this.activeThreadCount;
 
-			if (this.isLoggerTraceEnabled) {
-				this.logger.trace(() -> String.format("[%d] started, hasThreadPending was: %b, activeThreadCount now: %d",
-						Thread.currentThread().getId(), this.hasThreadPending, this.activeThreadCount));
-			}
+			this.logger.trace(() -> String.format("[%d] started, hasThreadPending was: %b, activeThreadCount now: %d",
+					Thread.currentThread().getId(), this.hasThreadPending, this.activeThreadCount));
 
 			// Defer clearing hasThreadPending to prevent unnecessary threads waiting to produce...
 			wasThreadPending = this.hasThreadPending;
 		}
 
 		try {
-			// It's possible this might need to become a class instance private volatile
-			boolean canBlock = false;
-
 			while (!Thread.currentThread().isInterrupted()) {
 				Task task = null;
+				String taskType;
 
-				if (this.isLoggerTraceEnabled) {
-					this.logger.trace(() -> String.format("[%d] waiting to produce...", Thread.currentThread().getId()));
-				}
+				this.logger.trace(() -> String.format("[%d] waiting to produce...", Thread.currentThread().getId()));
 
 				synchronized (this) {
 					if (wasThreadPending) {
@@ -141,13 +133,13 @@ public abstract class ExecuteProduceConsume implements Runnable {
 						wasThreadPending = false;
 					}
 
-					final boolean lambdaCanIdle = canBlock;
-					if (this.isLoggerTraceEnabled) {
-						this.logger.trace(() -> String.format("[%d] producing, activeThreadCount: %d, consumerCount: %d, canBlock is %b...",
-								Thread.currentThread().getId(), this.activeThreadCount, this.consumerCount, lambdaCanIdle));
-					}
+					// If we're the only non-consuming thread - producer can afford to block this round
+					boolean canBlock = this.activeThreadCount - this.consumerCount <= 1;
 
-					final long beforeProduce = isLoggerTraceEnabled ? System.currentTimeMillis() : 0;
+					this.logger.trace(() -> String.format("[%d] producing... [activeThreadCount: %d, consumerCount: %d, canBlock: %b]",
+							Thread.currentThread().getId(), this.activeThreadCount, this.consumerCount, canBlock));
+
+					final long beforeProduce = this.logger.isDebugEnabled() ? System.currentTimeMillis() : 0;
 
 					try {
 						task = produceTask(canBlock);
@@ -158,31 +150,36 @@ public abstract class ExecuteProduceConsume implements Runnable {
 						this.logger.warn(() -> String.format("[%d] exception while trying to produce task", Thread.currentThread().getId()), e);
 					}
 
-					if (this.isLoggerTraceEnabled) {
-						this.logger.trace(() -> String.format("[%d] producing took %dms", Thread.currentThread().getId(), System.currentTimeMillis() - beforeProduce));
+					if (this.logger.isDebugEnabled()) {
+						final long productionPeriod = System.currentTimeMillis() - beforeProduce;
+						taskType = task == null ? "no task" : task.getName();
+
+						this.logger.debug(() -> String.format("[%d] produced [%s] in %dms [canBlock: %b]",
+								Thread.currentThread().getId(),
+								taskType,
+								productionPeriod,
+								canBlock
+						));
+					} else {
+						taskType = null;
 					}
 				}
 
 				if (task == null)
 					synchronized (this) {
-						if (this.isLoggerTraceEnabled) {
-							this.logger.trace(() -> String.format("[%d] no task, activeThreadCount: %d, consumerCount: %d",
-									Thread.currentThread().getId(), this.activeThreadCount, this.consumerCount));
-						}
+						this.logger.trace(() -> String.format("[%d] no task, activeThreadCount: %d, consumerCount: %d",
+								Thread.currentThread().getId(), this.activeThreadCount, this.consumerCount));
 
-						if (this.activeThreadCount > this.consumerCount + 1) {
+						// If we have an excess of non-consuming threads then we can exit
+						if (this.activeThreadCount - this.consumerCount > 1) {
 							--this.activeThreadCount;
-							if (this.isLoggerTraceEnabled) {
-								this.logger.trace(() -> String.format("[%d] ending, activeThreadCount now: %d",
-										Thread.currentThread().getId(), this.activeThreadCount));
-							}
+
+							this.logger.trace(() -> String.format("[%d] ending, activeThreadCount now: %d",
+									Thread.currentThread().getId(), this.activeThreadCount));
 
 							return;
 						}
 
-						// We're the last surviving thread - producer can afford to block next round
-						canBlock = true;
-
 						continue;
 					}
 
@@ -192,16 +189,13 @@ public abstract class ExecuteProduceConsume implements Runnable {
 					++this.tasksProduced;
 					++this.consumerCount;
 
-					if (this.isLoggerTraceEnabled) {
-						this.logger.trace(() -> String.format("[%d] hasThreadPending: %b, activeThreadCount: %d, consumerCount now: %d",
-								Thread.currentThread().getId(), this.hasThreadPending, this.activeThreadCount, this.consumerCount));
-					}
+					this.logger.trace(() -> String.format("[%d] hasThreadPending: %b, activeThreadCount: %d, consumerCount now: %d",
+							Thread.currentThread().getId(), this.hasThreadPending, this.activeThreadCount, this.consumerCount));
 
 					// If we have no thread pending and no excess of threads then we should spawn a fresh thread
-					if (!this.hasThreadPending && this.activeThreadCount <= this.consumerCount + 1) {
-						if (this.isLoggerTraceEnabled) {
-							this.logger.trace(() -> String.format("[%d] spawning another thread", Thread.currentThread().getId()));
-						}
+					if (!this.hasThreadPending && this.activeThreadCount == this.consumerCount) {
+						this.logger.trace(() -> String.format("[%d] spawning another thread", Thread.currentThread().getId()));
+
 						this.hasThreadPending = true;
 
 						try {
@@ -209,21 +203,19 @@ public abstract class ExecuteProduceConsume implements Runnable {
 						} catch (RejectedExecutionException e) {
 							++this.spawnFailures;
 							this.hasThreadPending = false;
-							if (this.isLoggerTraceEnabled) {
-								this.logger.trace(() -> String.format("[%d] failed to spawn another thread", Thread.currentThread().getId()));
-							}
+
+							this.logger.trace(() -> String.format("[%d] failed to spawn another thread", Thread.currentThread().getId()));
+
 							this.onSpawnFailure();
 						}
 					} else {
-						if (this.isLoggerTraceEnabled) {
-							this.logger.trace(() -> String.format("[%d] NOT spawning another thread", Thread.currentThread().getId()));
-						}
+						this.logger.trace(() -> String.format("[%d] NOT spawning another thread", Thread.currentThread().getId()));
 					}
 				}
 
-				if (this.isLoggerTraceEnabled) {
-					this.logger.trace(() -> String.format("[%d] performing task...", Thread.currentThread().getId()));
-				}
+				this.logger.trace(() -> String.format("[%d] consuming [%s] task...", Thread.currentThread().getId(), taskType));
+
+				final long beforePerform = this.logger.isDebugEnabled() ? System.currentTimeMillis() : 0;
 
 				try {
 					task.perform(); // This can block for a while
@@ -231,29 +223,25 @@ public abstract class ExecuteProduceConsume implements Runnable {
 					// We're in shutdown situation so exit
 					Thread.currentThread().interrupt();
 				} catch (Exception e) {
-					this.logger.warn(() -> String.format("[%d] exception while performing task", Thread.currentThread().getId()), e);
+					this.logger.warn(() -> String.format("[%d] exception while consuming task", Thread.currentThread().getId()), e);
 				}
 
-				if (this.isLoggerTraceEnabled) {
-					this.logger.trace(() -> String.format("[%d] finished task", Thread.currentThread().getId()));
+				if (this.logger.isDebugEnabled()) {
+					final long productionPeriod = System.currentTimeMillis() - beforePerform;
+
+					this.logger.debug(() -> String.format("[%d] consumed [%s] task in %dms", Thread.currentThread().getId(), taskType, productionPeriod));
 				}
 
 				synchronized (this) {
 					++this.tasksConsumed;
 					--this.consumerCount;
 
-					if (this.isLoggerTraceEnabled) {
-						this.logger.trace(() -> String.format("[%d] consumerCount now: %d",
-								Thread.currentThread().getId(), this.consumerCount));
-					}
-
-					// Quicker, non-blocking produce next round
-					canBlock = false;
+					this.logger.trace(() -> String.format("[%d] consumerCount now: %d",
+							Thread.currentThread().getId(), this.consumerCount));
 				}
 			}
 		} finally {
-			if (this.isLoggerTraceEnabled)
-				Thread.currentThread().setName(this.className);
+			Thread.currentThread().setName(this.className);
 		}
 	}
 

src/main/java/org/qortal/utils/Unicode.java

@@ -18,6 +18,9 @@ import java.util.TreeMap;
 
 import com.google.common.base.CharMatcher;
 
+import com.ibm.icu.text.CaseMap;
+import com.ibm.icu.text.Normalizer2;
+import com.ibm.icu.text.UnicodeSet;
 import net.codebox.homoglyph.HomoglyphBuilder;
 
 public abstract class Unicode {
@@ -31,6 +34,8 @@ public abstract class Unicode {
 	public static final String ZERO_WIDTH_NO_BREAK_SPACE = "\ufeff";
 
 	public static final CharMatcher ZERO_WIDTH_CHAR_MATCHER = CharMatcher.anyOf(ZERO_WIDTH_SPACE + ZERO_WIDTH_NON_JOINER + ZERO_WIDTH_JOINER + WORD_JOINER + ZERO_WIDTH_NO_BREAK_SPACE);
+	private static final UnicodeSet removableUniset = new UnicodeSet("[[:Mark:][:Other:]]").freeze();
+
 
 	private static int[] homoglyphCodePoints;
 	private static int[] reducedCodePoints;
@@ -59,7 +64,7 @@ public abstract class Unicode {
 	public static String normalize(String input) {
 		String output;
 
-		// Normalize
+		// Normalize using NFKC to recompose in canonical form
 		output = Normalizer.normalize(input, Form.NFKC);
 
 		// Remove zero-width code-points, used for rendering
@@ -91,8 +96,8 @@ public abstract class Unicode {
 	public static String sanitize(String input) {
 		String output;
 
-		// Normalize
-		output = Normalizer.normalize(input, Form.NFKD);
+		// Normalize using NFKD to decompose into individual combining code points
+		output = Normalizer2.getNFKDInstance().normalize(input);
 
 		// Remove zero-width code-points, used for rendering
 		output = removeZeroWidth(output);
@@ -100,11 +105,11 @@ public abstract class Unicode {
 		// Normalize whitespace
 		output = CharMatcher.whitespace().trimAndCollapseFrom(output, ' ');
 
-		// Remove accents, combining marks
-		output = output.replaceAll("[\\p{M}\\p{C}]", "");
+		// Remove accents, combining marks - see https://www.unicode.org/reports/tr44/#GC_Values_Table
+		output = removableUniset.stripFrom(output, true);
 
 		// Convert to lowercase
-		output = output.toLowerCase(Locale.ROOT);
+		output = CaseMap.toLower().apply(Locale.ROOT, output);
 
 		// Reduce homoglyphs
 		output = reduceHomoglyphs(output);

src/main/resources/blockchain.json

@@ -4,8 +4,10 @@
 	"maxBlockSize": 2097152,
 	"maxBytesPerUnitFee": 1024,
 	"unitFee": "0.001",
-	"nameRegistrationUnitFee": "5",
-	"nameRegistrationUnitFeeTimestamp": 1645372800000,
+	"nameRegistrationUnitFees": [
+		{ "timestamp": 1645372800000, "fee": "5" },
+		{ "timestamp": 1651420800000, "fee": "1.25" }
+	],
 	"useBrokenMD160ForAddresses": false,
 	"requireGroupForApproval": false,
 	"defaultGroupId": 0,

src/main/resources/i18n/ApiError_de.properties

@@ -81,4 +81,3 @@ ORDER_SIZE_TOO_SMALL = order amount too low
 FILE_NOT_FOUND = Datei nicht gefunden
 
 NO_REPLY = peer did not reply with data
-

src/main/resources/i18n/ApiError_en.properties

@@ -68,7 +68,7 @@ ORDER_UNKNOWN = unknown asset order ID
 GROUP_UNKNOWN = group unknown
 
 ### Foreign Blockchain ###
-FOREIGN_BLOCKCHAIN_NETWORK_ISSUE = foreign blokchain or ElectrumX network issue
+FOREIGN_BLOCKCHAIN_NETWORK_ISSUE = foreign blockchain or ElectrumX network issue
 
 FOREIGN_BLOCKCHAIN_BALANCE_ISSUE = insufficient balance on foreign blockchain
 
@@ -80,8 +80,4 @@ ORDER_SIZE_TOO_SMALL = order amount too low
 ### Data ###
 FILE_NOT_FOUND = file not found
 
-ORDER_SIZE_TOO_SMALL = order size too small
-
-FILE_NOT_FOUND = file not found
-
 NO_REPLY = peer didn't reply within the allowed time

src/main/resources/i18n/ApiError_es.properties

@@ -0,0 +1,83 @@
+#Generated by ResourceBundle Editor (http://essiembre.github.io/eclipse-rbe/)
+# Keys are from api.ApiError enum
+
+# "localeLang": "es",
+
+### Common ###
+JSON = no se pudo analizar el mensaje JSON
+
+INSUFFICIENT_BALANCE = saldo insuficiente
+
+UNAUTHORIZED = Llamada API no autorizada
+
+REPOSITORY_ISSUE = error de repositorio
+
+NON_PRODUCTION = esta llamada API no está permitida para sistemas de producción
+
+BLOCKCHAIN_NEEDS_SYNC = blockchain necesita sincronizarse primero
+
+NO_TIME_SYNC = aún no hay sincronización de reloj
+
+### Validation ###
+INVALID_SIGNATURE = firma no válida
+
+INVALID_ADDRESS = dirección no válida
+
+INVALID_PUBLIC_KEY = clave pública no válida
+
+INVALID_DATA = datos no válidos
+
+INVALID_NETWORK_ADDRESS = dirección de red no válida
+
+ADDRESS_UNKNOWN = dirección de cuenta desconocida
+
+INVALID_CRITERIA = criterio de búsqueda no válido
+
+INVALID_REFERENCE = referencia no válida
+
+TRANSFORMATION_ERROR = no se pudo transformar JSON en transacción
+
+INVALID_PRIVATE_KEY = clave privada no válida
+
+INVALID_HEIGHT = altura de bloque no válida
+
+CANNOT_MINT = la cuenta no puede acuñar
+
+### Blocks ###
+BLOCK_UNKNOWN = bloque desconocido
+
+### Transactions ###
+TRANSACTION_UNKNOWN = transacción desconocida
+
+PUBLIC_KEY_NOT_FOUND = clave pública no encontrada
+
+# this one is special in that caller expected to pass two additional strings, hence the two %s
+TRANSACTION_INVALID = transacción no válida: %s (%s)
+
+### Naming ###
+NAME_UNKNOWN = nombre desconocido
+
+### Asset ###
+INVALID_ASSET_ID = ID de recurso no válido
+
+INVALID_ORDER_ID = ID de pedido de activo no válido
+
+ORDER_UNKNOWN = ID de pedido de activo desconocido
+
+### Groups ###
+GROUP_UNKNOWN = grupo desconocido
+
+### Foreign Blockchain ###
+FOREIGN_BLOCKCHAIN_NETWORK_ISSUE = problema de cadena de bloques extranjera o red ElectrumX
+
+FOREIGN_BLOCKCHAIN_BALANCE_ISSUE = saldo insuficiente en blockchain extranjera
+
+FOREIGN_BLOCKCHAIN_TOO_SOON = demasiado pronto para transmitir transacciones de blockchain extranjeras (LockTime/mediana de tiempo de bloqueo)
+
+### Trade Portal ###
+ORDER_SIZE_TOO_SMALL = importe del pedido demasiado bajo
+
+### Data ###
+FILE_NOT_FOUND = archivo no encontrado
+
+NO_REPLY = el compañero no respondió dentro del tiempo permitido

src/main/resources/i18n/ApiError_fi.properties

@@ -1,10 +1,7 @@
 #Generated by ResourceBundle Editor (http://essiembre.github.io/eclipse-rbe/)
 # Keys are from api.ApiError enum
 
-# Kielen muuttaminen suomeksi tapahtuu settings.json-tiedostossa
-#
 # "localeLang": "fi",
-# muista pilkku lopussa  jos komento ei ole viimeisellä rivillä
 
 ### Common ###
 JSON = JSON-viestin jaottelu epäonnistui
@@ -83,4 +80,4 @@ ORDER_SIZE_TOO_SMALL = order amount too low
 ### Data ###
 FILE_NOT_FOUND = file not found
 
-NO_REPLY = peer did not reply with data
+NO_REPLY = peer did not reply with data

src/main/resources/i18n/ApiError_fr.properties

@@ -1,24 +1,46 @@
-### Commun ###
+#Generated by ResourceBundle Editor (http://essiembre.github.io/eclipse-rbe/)
+# Keys are from api.ApiError enum
+
+# "localeLang": "fr",
+
+### Commun ###
 JSON = échec de l'analyse du message JSON
+
 INSUFFICIENT_BALANCE = balance insuffisante
+
 UNAUTHORIZED = appel de l’API non autorisé
+
 REPOSITORY_ISSUE = erreur de dépôt
+
 NON_PRODUCTION = cet appel API n'est pas autorisé pour les systèmes en production
+
 BLOCKCHAIN_NEEDS_SYNC = la blockchain doit d'abord être synchronisée
+
 NO_TIME_SYNC = heure pas encore synchronisée
 
 ### Validation ###
 INVALID_SIGNATURE = signature invalide
+
 INVALID_ADDRESS = adresse invalide
+
 INVALID_PUBLIC_KEY = clé publique invalide
+
 INVALID_DATA = données invalides
+
 INVALID_NETWORK_ADDRESS = adresse réseau invalide
+
 ADDRESS_UNKNOWN = adresse de compte inconnue
+
 INVALID_CRITERIA = critère de recherche invalide
+
 INVALID_REFERENCE = référence invalide
+
 TRANSFORMATION_ERROR = ne peut pas transformer JSON en transaction
+
 INVALID_PRIVATE_KEY = clé privée invalide
+
 INVALID_HEIGHT = hauteur de bloc invalide
+
 CANNOT_MINT = le compte ne peut pas mint
 
 ### Blocks ###
@@ -26,6 +48,7 @@ BLOCK_UNKNOWN = bloc inconnu
 
 ### Transactions ###
 TRANSACTION_UNKNOWN = opération inconnue
+
 PUBLIC_KEY_NOT_FOUND = clé publique introuvable
 
 # celui-ci est spécial dans le sens où l'appelant doit passer deux chaînes supplémentaires, d'où les deux %s
@@ -36,7 +59,9 @@ NAME_UNKNOWN = nom inconnu
 
 ### Asset ###
 INVALID_ASSET_ID = identifiant d'actif invalide
+
 INVALID_ORDER_ID = identifiant de commande d'actif non valide
+
 ORDER_UNKNOWN = identifiant d'ordre d'actif inconnu
 
 ### Groupes ###
@@ -44,7 +69,9 @@ GROUP_UNKNOWN = groupe inconnu
 
 ### Blockchain étrangère ###
 FOREIGN_BLOCKCHAIN_NETWORK_ISSUE = Problème blokchain étrangère ou  de réseau ElectrumX
+
 FOREIGN_BLOCKCHAIN_BALANCE_ISSUE = solde insuffisant sur la blockchain étrangère
+
 FOREIGN_BLOCKCHAIN_TOO_SOON = trop tôt pour diffuser la transaction sur la blockchain étrangère (temps de verrouillage/temps de bloc médian)
 
 ### Portail de trading ###
@@ -52,4 +79,5 @@ ORDER_SIZE_TOO_SMALL = montant de commande trop bas
 
 ### Données ###
 FILE_NOT_FOUND = fichier introuvable
-NO_REPLY = le pair n'a pas renvoyé de données
+
+NO_REPLY = le pair n'a pas renvoyé de données

src/main/resources/i18n/ApiError_hu.properties

@@ -1,8 +1,5 @@
 #Generated by ResourceBundle Editor (http://essiembre.github.io/eclipse-rbe/)
-# Keys are from api.ApiError enum
-
-# Magyar myelvre forditotta: Szkíta (Scythian). 2021 Augusztus 7.
-# Az alkalmazás nyelvének magyarra való változtatása a settings.json oldalon történik.
+# Keys are from api.ApiError enum # Magyar nyelvre forditotta: Szkíta (Scythian). 2021 Augusztus 7.
 
 # "localeLang": "hu",
 
@@ -15,7 +12,7 @@ UNAUTHORIZED = nem engedélyezett API-hívás
 
 REPOSITORY_ISSUE = adattári hiba
 
-NON_PRODUCTION = ez az API-hívás nem engedélyezett korlátozott rendszereken
+NON_PRODUCTION = ez az API-hívás nem engedélyezett éles rendszereken
 
 BLOCKCHAIN_NEEDS_SYNC = a blokkláncnak még szinkronizálnia kell
 
@@ -24,15 +21,15 @@ NO_TIME_SYNC = az óraszinkronizálás még nem történt meg
 ### Validation ###
 INVALID_SIGNATURE = érvénytelen aláírás
 
-INVALID_ADDRESS = érvénytelen fiók cím
+INVALID_ADDRESS = érvénytelen fiókcím
 
 INVALID_PUBLIC_KEY = érvénytelen nyilvános kulcs
 
 INVALID_DATA = érvénytelen adat
 
-INVALID_NETWORK_ADDRESS = érvénytelen hálózat cím
+INVALID_NETWORK_ADDRESS = érvénytelen hálózatcím
 
-ADDRESS_UNKNOWN = ismeretlen fiók cím
+ADDRESS_UNKNOWN = ismeretlen fiókcím
 
 INVALID_CRITERIA = érvénytelen keresési feltétel
 
@@ -83,4 +80,4 @@ ORDER_SIZE_TOO_SMALL = rendelési összeg túl alacsony
 ### Data ###
 FILE_NOT_FOUND = fájl nem található
 
-NO_REPLY = a másik csomópont nem válaszolt
+NO_REPLY = a másik csomópont nem válaszolt

src/main/resources/i18n/ApiError_it.properties

@@ -1,26 +1,22 @@
 #Generated by ResourceBundle Editor (http://essiembre.github.io/eclipse-rbe/)
-# Keys are from api.ApiError enum
-# Italian translation by Pabs 2021
+# Keys are from api.ApiError enum # Italian translation by Pabs 2021
 
-# La modifica della lingua dell'UI è fatta nel file Settings.json
-#
 # "localeLang": "it",
-# Si prega ricordare la virgola alla fine, se questo comando non è sull'ultima riga
 
 ### Common ###
 JSON = Impossibile analizzare il messaggio JSON
 
-INSUFFICIENT_BALANCE = insufficient balance
+INSUFFICIENT_BALANCE = bilancio insufficiente
 
 UNAUTHORIZED = Chiamata API non autorizzata
 
-REPOSITORY_ISSUE = errore del repositorio
+REPOSITORY_ISSUE = errore del repository
 
 NON_PRODUCTION = questa chiamata API non è consentita per i sistemi di produzione
 
-BLOCKCHAIN_NEEDS_SYNC = blockchain deve prima sincronizzarsi
+BLOCKCHAIN_NEEDS_SYNC = la blockchain deve sincronizzarsi
 
-NO_TIME_SYNC = nessuna sincronizzazione dell'orologio ancora
+NO_TIME_SYNC = nessuna sincronizzazione
 
 ### Validation ###
 INVALID_SIGNATURE = firma non valida
@@ -39,7 +35,7 @@ INVALID_CRITERIA = criteri di ricerca non validi
 
 INVALID_REFERENCE = riferimento non valido
 
-TRANSFORMATION_ERROR = non è stato possibile trasformare JSON in transazione
+TRANSFORMATION_ERROR = non è stato possibile trasformare il JSON
 
 INVALID_PRIVATE_KEY = chiave privata non valida
 
@@ -62,26 +58,26 @@ TRANSACTION_INVALID = transazione non valida: %s (%s)
 NAME_UNKNOWN = nome sconosciuto
 
 ### Asset ###
-INVALID_ASSET_ID = identificazione risorsa non valida
+INVALID_ASSET_ID = risorsa non valida
 
-INVALID_ORDER_ID = identificazione di ordine di risorsa non valida
+INVALID_ORDER_ID = ordine di risorsa non valida
 
-ORDER_UNKNOWN = identificazione di ordine di risorsa sconosciuta
+ORDER_UNKNOWN = ordine di risorsa sconosciuta
 
 ### Groups ###
 GROUP_UNKNOWN = gruppo sconosciuto
 
 ### Foreign Blockchain ###
-FOREIGN_BLOCKCHAIN_NETWORK_ISSUE = foreign blokchain or ElectrumX network issue
+FOREIGN_BLOCKCHAIN_NETWORK_ISSUE = problema nella blockchain esterna o nella rete ElectrumX
 
-FOREIGN_BLOCKCHAIN_BALANCE_ISSUE = insufficient balance on foreign blockchain
+FOREIGN_BLOCKCHAIN_BALANCE_ISSUE = bilancio insufficiente nella blockchain esterna
 
-FOREIGN_BLOCKCHAIN_TOO_SOON = too soon to broadcast foreign blockchain transaction (LockTime/median block time)
+FOREIGN_BLOCKCHAIN_TOO_SOON = troppo presto per distribuire la transazione (sospensione LockTime/median)
 
 ### Trade Portal ###
-ORDER_SIZE_TOO_SMALL = order amount too low
+ORDER_SIZE_TOO_SMALL = quantità d'ordine troppo bassa
 
 ### Data ###
 FILE_NOT_FOUND = file not found
 
-NO_REPLY = peer did not reply with data
+NO_REPLY = il peer non ha fornito dati

src/main/resources/i18n/ApiError_nl.properties

@@ -41,7 +41,7 @@ INVALID_PRIVATE_KEY = ongeldige private key
 
 INVALID_HEIGHT = ongeldige blokhoogte
 
-CANNOT_MINT = account kan niet munten
+CANNOT_MINT = account kan niet minten
 
 ### Blocks ###
 BLOCK_UNKNOWN = blok onbekend
@@ -68,16 +68,16 @@ ORDER_UNKNOWN = onbekende asset order ID
 GROUP_UNKNOWN = onbekende groep
 
 ### Foreign Blockchain ###
-FOREIGN_BLOCKCHAIN_NETWORK_ISSUE = foreign blokchain or ElectrumX network issue
+FOREIGN_BLOCKCHAIN_NETWORK_ISSUE = blockchain of ElectrumX network probleem
 
-FOREIGN_BLOCKCHAIN_BALANCE_ISSUE = insufficient balance on foreign blockchain
+FOREIGN_BLOCKCHAIN_BALANCE_ISSUE = onvoldoende saldo blockchain
 
-FOREIGN_BLOCKCHAIN_TOO_SOON = too soon to broadcast foreign blockchain transaction (LockTime/median block time)
+FOREIGN_BLOCKCHAIN_TOO_SOON = nog niet gereed om de blockchain transactie uittevoeren (LockTime/median block time)
 
 ### Trade Portal ###
-ORDER_SIZE_TOO_SMALL = order amount too low
+ORDER_SIZE_TOO_SMALL = order bedrag te laag
 
 ### Data ###
-FILE_NOT_FOUND = file not found
+FILE_NOT_FOUND = file niet gevonden
 
-NO_REPLY = peer did not reply with data
+NO_REPLY = peer reageerd niet met data

src/main/resources/i18n/ApiError_ru.properties

@@ -1,83 +1,83 @@
-#Generated by ResourceBundle Editor (http://essiembre.github.io/eclipse-rbe/)
-# Keys are from api.ApiError enum
-
-# "localeLang": "ru",
-
-### Common ###
-JSON = не удалось разобрать сообщение json
-
-INSUFFICIENT_BALANCE = insufficient balance
-
-UNAUTHORIZED = вызов API не авторизован
-
-REPOSITORY_ISSUE = ошибка репозитория
-
-NON_PRODUCTION = этот вызов API не разрешен для производственных систем
-
-BLOCKCHAIN_NEEDS_SYNC = блокчейн должен сначала синхронизироваться
-
-NO_TIME_SYNC = no clock synchronization yet
-
-### Validation ###
-INVALID_SIGNATURE = недействительная подпись
-
-INVALID_ADDRESS = неизвестный адрес
-
-INVALID_PUBLIC_KEY = недействительный открытый ключ
-
-INVALID_DATA = неверные данные
-
-INVALID_NETWORK_ADDRESS = неверный сетевой адрес
-
-ADDRESS_UNKNOWN = неизвестная учетная запись
-
-INVALID_CRITERIA = неверные критерии поиска
-
-INVALID_REFERENCE = неверная ссылка
-
-TRANSFORMATION_ERROR = не удалось преобразовать JSON в транзакцию
-
-INVALID_PRIVATE_KEY = неверный приватный ключ
-
-INVALID_HEIGHT = недопустимая высота блока
-
-CANNOT_MINT = аккаунт не может чеканить
-
-### Blocks ###
-BLOCK_UNKNOWN = неизвестный блок
-
-### Transactions ###
-TRANSACTION_UNKNOWN = транзакция неизвестна
-
-PUBLIC_KEY_NOT_FOUND = открытый ключ не найден
-
-# this one is special in that caller expected to pass two additional strings, hence the two %s
-TRANSACTION_INVALID = транзакция недействительна: %s (%s)
-
-### Naming ###
-NAME_UNKNOWN = имя неизвестно
-
-### Asset ###
-INVALID_ASSET_ID = неверный идентификатор актива
-
-INVALID_ORDER_ID = неверный идентификатор заказа актива
-
-ORDER_UNKNOWN = неизвестный идентификатор заказа актива
-
-### Groups ###
-GROUP_UNKNOWN = неизвестная группа
-
-### Foreign Blockchain ###
-FOREIGN_BLOCKCHAIN_NETWORK_ISSUE = foreign blokchain or ElectrumX network issue
-
-FOREIGN_BLOCKCHAIN_BALANCE_ISSUE = insufficient balance on foreign blockchain
-
-FOREIGN_BLOCKCHAIN_TOO_SOON = too soon to broadcast foreign blockchain transaction (LockTime/median block time)
-
-### Trade Portal ###
-ORDER_SIZE_TOO_SMALL = order amount too low
-
-### Data ###
-FILE_NOT_FOUND = file not found
-
-NO_REPLY = peer did not reply with data
+#Generated by ResourceBundle Editor (http://essiembre.github.io/eclipse-rbe/)
+# Keys are from api.ApiError enum
+
+# "localeLang": "ru",
+
+### Common ###
+JSON = не удалось разобрать сообщение json
+
+INSUFFICIENT_BALANCE = недостаточный баланс
+
+UNAUTHORIZED = вызов API не авторизован
+
+REPOSITORY_ISSUE = ошибка репозитория
+
+NON_PRODUCTION = этот вызов API не разрешен для производственных систем
+
+BLOCKCHAIN_NEEDS_SYNC = блокчейн должен сначала синхронизироваться
+
+NO_TIME_SYNC = пока нет синхронизации часов
+
+### Validation ###
+INVALID_SIGNATURE = недействительная подпись
+
+INVALID_ADDRESS = неизвестный адрес
+
+INVALID_PUBLIC_KEY = недействительный открытый ключ
+
+INVALID_DATA = неверные данные
+
+INVALID_NETWORK_ADDRESS = неверный адрес сети
+
+ADDRESS_UNKNOWN = неизвестная учетная запись
+
+INVALID_CRITERIA = неверные критерии поиска
+
+INVALID_REFERENCE = неверная ссылка
+
+TRANSFORMATION_ERROR = не удалось преобразовать JSON в транзакцию
+
+INVALID_PRIVATE_KEY = неверный приватный ключ
+
+INVALID_HEIGHT = недопустимая высота блока
+
+CANNOT_MINT = аккаунт не может чеканить
+
+### Blocks ###
+BLOCK_UNKNOWN = неизвестный блок
+
+### Transactions ###
+TRANSACTION_UNKNOWN = транзакция неизвестна
+
+PUBLIC_KEY_NOT_FOUND = открытый ключ не найден
+
+# this one is special in that caller expected to pass two additional strings, hence the two %s
+TRANSACTION_INVALID = транзакция недействительна: %s (%s)
+
+### Naming ###
+NAME_UNKNOWN = имя неизвестно
+
+### Asset ###
+INVALID_ASSET_ID = неверный идентификатор актива
+
+INVALID_ORDER_ID = неверный идентификатор заказа актива
+
+ORDER_UNKNOWN = неизвестный идентификатор заказа актива
+
+### Groups ###
+GROUP_UNKNOWN = неизвестная группа
+
+### Foreign Blockchain ###
+FOREIGN_BLOCKCHAIN_NETWORK_ISSUE = проблема с внешним блокчейном или сетью ElectrumX
+
+FOREIGN_BLOCKCHAIN_BALANCE_ISSUE = недостаточный баланс на внешнем блокчейне
+
+FOREIGN_BLOCKCHAIN_TOO_SOON = слишком рано для трансляции транзакции во внений блокчей (время блокировки/среднее время блока)
+
+### Trade Portal ###
+ORDER_SIZE_TOO_SMALL = слишком маленькая сумма ордера
+
+### Data ###
+FILE_NOT_FOUND = файл не найден
+
+NO_REPLY = узел не ответил данными

src/main/resources/i18n/ApiError_sv.properties

@@ -0,0 +1,83 @@
+#Generated by ResourceBundle Editor (http://essiembre.github.io/eclipse-rbe/)
+# Keys are from api.ApiError enum
+
+# "localeLang": "sv",
+
+### Common ###
+JSON = misslyckades att tolka JSON meddelande
+
+INSUFFICIENT_BALANCE = otillräcklig balans
+
+UNAUTHORIZED = API obehörigt anrop
+
+REPOSITORY_ISSUE = fel i lagret
+
+NON_PRODUCTION = detta API-anrop är inte tillåtet för produktionssystem
+
+BLOCKCHAIN_NEEDS_SYNC = blockchain måste synkroniseras först
+
+NO_TIME_SYNC = ingen klocksynkronisering ännu
+
+### Validation ###
+INVALID_SIGNATURE = ogiltig signatur
+
+INVALID_ADDRESS = ogiltig adress
+
+INVALID_PUBLIC_KEY = ogiltig offentlig nyckel
+
+INVALID_DATA = ogiltig data
+
+INVALID_NETWORK_ADDRESS = ogiltig nätverksadress
+
+ADDRESS_UNKNOWN = okänd kontoadress
+
+INVALID_CRITERIA = ogiltiga sökkriterier
+
+INVALID_REFERENCE = ogiltig referens
+
+TRANSFORMATION_ERROR = kunde inte omvandla JSON till en transaktion
+
+INVALID_PRIVATE_KEY = ogiltig privat nyckel
+
+INVALID_HEIGHT = ogiltig blockhöjd
+
+CANNOT_MINT = konto kan inte prägla QORT
+
+### Blocks ###
+BLOCK_UNKNOWN = okänt block
+
+### Transactions ###
+TRANSACTION_UNKNOWN = okänd transaktion
+
+PUBLIC_KEY_NOT_FOUND = hittade inte en offentlig nyckel
+
+# this one is special in that caller expected to pass two additional strings, hence the two %s
+TRANSACTION_INVALID = ogiltig transaktion: %s (%s)
+
+### Naming ###
+NAME_UNKNOWN = okänt namn
+
+### Asset ###
+INVALID_ASSET_ID = ogiltigt tillgångs-ID
+
+INVALID_ORDER_ID = ogiltigt tillgångsbeställnings-ID
+
+ORDER_UNKNOWN = okänt tillgångsbeställnings-ID
+
+### Groups ###
+GROUP_UNKNOWN = okänd grupp
+
+### Foreign Blockchain ###
+FOREIGN_BLOCKCHAIN_NETWORK_ISSUE = utländsk blockchain eller ElectrumX nätverksproblem
+
+FOREIGN_BLOCKCHAIN_BALANCE_ISSUE = otillräcklig balans på utländsk blockchain
+
+FOREIGN_BLOCKCHAIN_TOO_SOON = för tidigt för att sända utländsk blockkedjetransaktion (LockTime/medianblocktid)
+
+### Trade Portal ###
+ORDER_SIZE_TOO_SMALL = beställningssumman för låg
+
+### Data ###
+FILE_NOT_FOUND = filen hittades inte
+
+NO_REPLY = noden svarade inte inom den tillåtna tiden