Bump to v1.3.2

Also improved BTC.WalletAwareUTXOProvider to derive more keys itself
instead of throwing and relying on caller to do the work.
Added benefit of cleaning up caller code and being more efficient.
Needed because not all receiving/change addresses were being picked up.

WindowsInstaller/Install Files/AppData/settings.json

@@ -0,0 +1,3 @@
+{
+  "apiDocumentationEnabled": true
+}

WindowsInstaller/Install Files/log4j2.properties

@@ -0,0 +1,70 @@
+rootLogger.level = info
+# On Windows, uncomment next line to set dirname:
+# property.dirname = ${sys:user.home}\\AppData\\Local\\qortal\\
+property.filename = ${sys:log4j2.filenameTemplate:-log.txt}
+
+rootLogger.appenderRef.console.ref = stdout
+rootLogger.appenderRef.rolling.ref = FILE
+
+# Suppress extraneous bitcoinj library output
+logger.bitcoinj.name = org.bitcoinj
+logger.bitcoinj.level = error
+
+# Override HSQLDB logging level to "warn" as too much is logged at "info"
+logger.hsqldb.name = hsqldb.db
+logger.hsqldb.level = warn
+
+# Support optional, per-session HSQLDB debugging
+logger.hsqldbRepository.name = org.qortal.repository.hsqldb
+logger.hsqldbRepository.level = debug
+
+# Suppress extraneous Jersey warning
+logger.jerseyInject.name = org.glassfish.jersey.internal.inject.Providers
+logger.jerseyInject.level = off
+
+# Suppress extraneous Jersey EOF 'errors' (actually remote peers disconnecting early)
+logger.jerseyEOF.name = org.glassfish.jersey.server.internal
+logger.jerseyEOF.level = off
+
+# Suppress extraneous Jetty entries
+# 2019-02-14 11:46:27 INFO  ContextHandler:851 - Started o.e.j.s.ServletContextHandler@6949e948{/,null,AVAILABLE}
+# 2019-02-14 11:46:27 INFO  AbstractConnector:289 - Started ServerConnector@50ad322b{HTTP/1.1,[http/1.1]}{0.0.0.0:9085}
+# 2019-02-14 11:46:27 INFO  Server:374 - jetty-9.4.11.v20180605; built: 2018-06-05T18:24:03.829Z; git: d5fc0523cfa96bfebfbda19606cad384d772f04c; jvm 1.8.0_181-b13
+# 2019-02-14 11:46:27 INFO  Server:411 - Started @2539ms
+logger.jetty.name = org.eclipse.jetty
+logger.jetty.level = warn
+# Even more extraneous Jetty output
+# 2019-01-26 02:18:10 WARN  ResourceService:718 - java.util.concurrent.TimeoutException: Idle timeout expired: 30000/30000 ms
+logger.jettyRS.name = org.eclipse.jetty.server.ResourceService
+logger.jettyRS.level = error
+
+# Suppress extraneous slf4j entries
+# 2019-02-14 11:46:27 INFO  log:193 - Logging initialized @1636ms to org.eclipse.jetty.util.log.Slf4jLog
+logger.slf4j.name = org.slf4j
+logger.slf4j.level = warn
+
+# Suppress extraneous Reflections entry
+# 2019-02-27 10:45:25 WARN  Reflections:179 - given scan urls are empty. set urls in the configuration
+logger.orgReflections.name = org.reflections.Reflections
+logger.orgReflections.level = off
+logger.sunReflections.name = sun.reflect.Reflection
+logger.sunReflections.level = off
+
+appender.console.type = Console
+appender.console.name = stdout
+appender.console.layout.type = PatternLayout
+appender.console.layout.pattern = %d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
+appender.console.filter.threshold.type = ThresholdFilter
+appender.console.filter.threshold.level = error
+
+appender.rolling.type = RollingFile
+appender.rolling.name = FILE
+appender.rolling.layout.type = PatternLayout
+appender.rolling.layout.pattern = %d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
+appender.rolling.filePattern = ${dirname:-}${filename}.%i
+appender.rolling.policy.type = SizeBasedTriggeringPolicy
+appender.rolling.policy.size = 4MB
+# Set the immediate flush to true (default)
+# appender.rolling.immediateFlush = true
+# Set the append to true (default), should not overwrite
+# appender.rolling.append=true

WindowsInstaller/Install Files/ntpcfg.bat

@@ -0,0 +1,33 @@
+@echo off
+
+:: BatchGotAdmin
+:-------------------------------------
+REM  --> Check for permissions
+>nul 2>&1 "%SYSTEMROOT%\system32\cacls.exe" "%SYSTEMROOT%\system32\config\system"
+
+REM --> If error flag set, we do not have admin.
+if '%errorlevel%' NEQ '0' (
+    echo Requesting administrative privileges...
+    goto UACPrompt
+) else ( goto gotAdmin )
+
+:UACPrompt
+    echo Set UAC = CreateObject^("Shell.Application"^) > "%temp%\getadmin.vbs"
+    echo UAC.ShellExecute "%~s0", "", "", "runas", 1 >> "%temp%\getadmin.vbs"
+
+    "%temp%\getadmin.vbs"
+    exit /B
+
+:gotAdmin
+    if exist "%temp%\getadmin.vbs" ( del "%temp%\getadmin.vbs" )
+    pushd "%CD%"
+    CD /D "%~dp0"
+:--------------------------------------
+
+net stop "Windows Time"
+
+w32tm /config "/manualpeerlist:pool.ntp.org 0.pool.ntp.org 1.pool.ntp.org 2.pool.ntp.org 3.pool.ntp.org cn.pool.ntp.org 0.cn.pool.ntp.org 1.cn.pool.ntp.org 2.cn.pool.ntp.org 3.cn.pool.ntp.org"
+
+net start "Windows Time"
+
+sc config w32time start= auto

WindowsInstaller/README.md

@@ -0,0 +1,26 @@
+# Windows installer
+
+## Prerequisites
+
+* AdvancedInstaller v16 or better, and enterprise licence if translations are required
+* Installed AdoptOpenJDK v11 64bit, full JDK *not* JRE
+
+## General build instructions
+
+If this is your first time opening the `qortal.aip` file then you might need to adjust
+configured paths, or create a dummy `D:` drive with the expected layout.
+
+Typical build procedure:
+
+* Overwrite the `qortal.jar` file in `Install-Files\`
+* Open AdvancedInstaller with qortal.aip file
+* If releasing a new version, change version number in:
+	+ "Product Information" side menu
+	+ "Product Details" side menu entry
+	+ "Product Details" tab in "Product Details" pane
+	+ "Product Version" entry box
+* Click away to a different side menu entry, e.g. "Resources" -> "Files and Folders"
+* You should be prompted whether to generate a new product key, click "Generate New"
+* Click "Build" button
+* New EXE should be generated in `Qortal-SetupFiles\` folder with correct version number
+

WindowsInstaller/dictionary.ail

@@ -0,0 +1,97 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<DICTIONARY type="multilanguage">
+  <!-- Control table -->
+  <ENTRY id="Control.Text.CustomizeDataPathDlg#Description">
+    <STRING lang="en" value="Do you want to store the blockchain, and other data, in a specific folder?"/>
+    <STRING lang="zh" value="你想把区块链数据存放在一个特定的文件夹吗？"/>
+    <STRING lang="zh_TW" value="你想把区块链数据存放在一个特定的文件夹吗？"/>
+  </ENTRY>
+  <ENTRY id="Control.Text.CustomizeDataPathDlg#Text">
+    <STRING lang="en" value="Select one of the options below, then click &quot;Next&quot;."/>
+    <STRING lang="zh" value="请选择，然后“下一步”"/>
+    <STRING lang="zh_TW" value="请选择，然后“下一步”"/>
+  </ENTRY>
+  <ENTRY id="Control.Text.CustomizeDataPathDlg#Title">
+    <STRING lang="en" value="Choose Custom Data Storage Folder?"/>
+    <STRING lang="zh" value="选择数据保存的文件夹?"/>
+    <STRING lang="zh_TW" value="选择数据保存的文件夹?"/>
+  </ENTRY>
+  <ENTRY id="Control.Text.CustomizeDbDlg#Description">
+    <STRING lang="en" value="Do you want to store the blockchain, and other data, in a specific folder?"/>
+    <STRING lang="zh" value="Do you want to store the blockchain, and other data, in a specific folder?"/>
+    <STRING lang="zh_TW" value="Do you want to store the blockchain, and other data, in a specific folder?"/>
+  </ENTRY>
+  <ENTRY id="Control.Text.CustomizeDbDlg#Title">
+    <STRING lang="en" value="Choose Custom Data Storage Folder?"/>
+    <STRING lang="zh" value="Choose Custom Data Storage Folder?"/>
+    <STRING lang="zh_TW" value="Choose Custom Data Storage Folder?"/>
+  </ENTRY>
+  <ENTRY id="Control.Text.DataFolderDlg#Description">
+    <STRING lang="en" value="This is the folder where the blockchain, and other data, will be stored."/>
+    <STRING lang="zh" value="这里是区块链及其它数据存放的文件夹"/>
+    <STRING lang="zh_TW" value="这里是区块链及其它数据存放的文件夹"/>
+  </ENTRY>
+  <ENTRY id="Control.Text.DataFolderDlg#Text">
+    <STRING lang="en" value="To store data in this folder, click &quot;[Text_Next]&quot;. To store data in a different folder, enter it below or click &quot;Browse&quot;."/>
+    <STRING lang="zh" value="如果存放在这个文件夹，点 “下一步”。如果存放在其它位置，请选择“浏览”。"/>
+    <STRING lang="zh_TW" value="如果存放在这个文件夹，点 “下一步”。如果存放在其它位置，请选择“浏览”。"/>
+  </ENTRY>
+  <ENTRY id="Control.Text.DataFolderDlg#Title">
+    <STRING lang="en" value="Select Data Storage Folder"/>
+    <STRING lang="zh" value="请选择文件存储地方"/>
+    <STRING lang="zh_TW" value="请选择文件存储地方"/>
+  </ENTRY>
+  <ENTRY id="Control.Text.DbFolderDlg#Description">
+    <STRING lang="en" value="This is the folder where the blockchain, and other data, will be stored."/>
+    <STRING lang="zh" value="This is the folder where the blockchain, and other data, will be stored."/>
+    <STRING lang="zh_TW" value="This is the folder where the blockchain, and other data, will be stored."/>
+  </ENTRY>
+  <ENTRY id="Control.Text.DbFolderDlg#Title">
+    <STRING lang="en" value="Select Data Storage Folder"/>
+    <STRING lang="zh" value="请选择文件存储地方"/>
+    <STRING lang="zh_TW" value="请选择文件存储地方"/>
+  </ENTRY>
+  <ENTRY id="Control.Text.NTPDialog#Description">
+    <STRING lang="en" value="Reconfigure Windows for more accurate time?"/>
+    <STRING lang="zh" value="重新配置Windows以获得更准确的时间？"/>
+  </ENTRY>
+  <ENTRY id="Control.Text.NTPDialog#Text_1">
+    <STRING lang="en" value="An accurate Windows clock is required to connect to the [ProductName] network and make transactions."/>
+    <STRING lang="zh" value="需要准确的Windows时钟才能连接到[ProductName]网络并进行交易。"/>
+  </ENTRY>
+  <ENTRY id="Control.Text.NTPDialog#Text_2">
+    <STRING lang="en" value="Select one of the options below, then click &quot;Next&quot;."/>
+    <STRING lang="zh" value="请选择，然后“下一步”"/>
+  </ENTRY>
+  <ENTRY id="Control.Text.NTPDialog#Text_3">
+    <STRING lang="en" value="Your computer&apos;s clock needs to be accurate to within 0.5 seconds."/>
+    <STRING lang="zh" value="您的计算机时钟需要准确到0.5秒内。"/>
+  </ENTRY>
+  <ENTRY id="Control.Text.NTPDialog#Title">
+    <STRING lang="en" value="Windows clock accuracy"/>
+    <STRING lang="zh" value="Windows 时钟精度"/>
+  </ENTRY>
+  <ENTRY id="Control.Text.VerifyRemoveDlg#RemoveBlockchainCheckbox">
+    <STRING lang="en" value="Remove downloaded blockchain and other data"/>
+    <STRING lang="zh" value="删除您下载的区块链"/>
+  </ENTRY>
+  <!-- RadioButton table -->
+  <ENTRY id="RadioButton.Text.CUSTOM_DB_BOOL#choose">
+    <STRING lang="en" value="Choose custom data storage folder..."/>
+    <STRING lang="zh" value="选择特定的文件夹存储"/>
+    <STRING lang="zh_TW" value="选择特定的文件夹存储"/>
+  </ENTRY>
+  <ENTRY id="RadioButton.Text.CUSTOM_DB_BOOL#default">
+    <STRING lang="en" value="Use default location "/>
+    <STRING lang="zh" value="使用默认存储地点"/>
+    <STRING lang="zh_TW" value="使用默认存储地点"/>
+  </ENTRY>
+  <ENTRY id="RadioButton.Text.RECONFIG_NTP#1">
+    <STRING lang="en" value="Yes, configure Windows to use internet time servers (Recommended)"/>
+    <STRING lang="zh" value="是，将Windows配置为使用多个Internet时间服务器 (推荐的)"/>
+  </ENTRY>
+  <ENTRY id="RadioButton.Text.RECONFIG_NTP#2">
+    <STRING lang="en" value="No, I will manage clock accuracy myself"/>
+    <STRING lang="zh" value="不，我会自己管理时钟精度。"/>
+  </ENTRY>
+</DICTIONARY>

lib/org/ciyam/AT/1.3.7/AT-1.3.7.pom

@@ -4,6 +4,6 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>org.ciyam</groupId>
   <artifactId>AT</artifactId>
-  <version>1.3.4</version>
+  <version>1.3.7</version>
   <description>POM was created from install:install-file</description>
 </project>

lib/org/ciyam/AT/maven-metadata-local.xml

@@ -3,10 +3,13 @@
   <groupId>org.ciyam</groupId>
   <artifactId>AT</artifactId>
   <versioning>
-    <release>1.3.4</release>
+    <release>1.3.7</release>
     <versions>
       <version>1.3.4</version>
+      <version>1.3.5</version>
+      <version>1.3.6</version>
+      <version>1.3.7</version>
     </versions>
-    <lastUpdated>20200414162728</lastUpdated>
+    <lastUpdated>20200812131412</lastUpdated>
   </versioning>
 </metadata>

pom.xml

@@ -3,13 +3,13 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>org.qortal</groupId>
 	<artifactId>qortal</artifactId>
-	<version>1.2.0</version>
+	<version>1.3.2</version>
 	<packaging>jar</packaging>
 	<properties>
 		<bitcoinj.version>0.15.5</bitcoinj.version>
 		<bouncycastle.version>1.64</bouncycastle.version>
 		<build.timestamp>${maven.build.timestamp}</build.timestamp>
-		<ciyam-at.version>1.3.4</ciyam-at.version>
+		<ciyam-at.version>1.3.7</ciyam-at.version>
 		<commons-net.version>3.6</commons-net.version>
 		<commons-text.version>1.8</commons-text.version>
 		<dagger.version>1.2.2</dagger.version>
@@ -17,7 +17,7 @@
 		<hsqldb.version>2.5.0-fixed</hsqldb.version>
 		<hsqldb-sqltool.version>2.5.0</hsqldb-sqltool.version>
 		<jersey.version>2.29.1</jersey.version>
-		<jetty.version>9.4.22.v20191022</jetty.version>
+		<jetty.version>9.4.29.v20200521</jetty.version>
 		<log4j.version>2.12.1</log4j.version>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 		<slf4j.version>1.7.12</slf4j.version>

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

@@ -128,8 +128,8 @@ public enum ApiError {
 
 	// Bitcoin
 	BTC_NETWORK_ISSUE(1201, 500),
-	BTC_BALANCE_ISSUE(1202, 422),
-	BTC_TOO_SOON(1203, 422);
+	BTC_BALANCE_ISSUE(1202, 402),
+	BTC_TOO_SOON(1203, 408);
 
 	private static final Map<Integer, ApiError> map = stream(ApiError.values()).collect(toMap(apiError -> apiError.code, apiError -> apiError));
 

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

@@ -3,6 +3,7 @@ package org.qortal.api;
 import java.io.IOException;
 
 import javax.servlet.RequestDispatcher;
+import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
@@ -17,7 +18,7 @@ public class ApiErrorHandler extends ErrorHandler {
 	private static final Logger LOGGER = LogManager.getLogger(ApiErrorHandler.class);
 
 	@Override
-	public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException {
+	public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
 		if (Settings.getInstance().isApiLoggingEnabled()) {
 			String requestURI = request.getRequestURI();
 

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

@@ -18,9 +18,9 @@ import org.eclipse.jetty.http.HttpVersion;
 import org.eclipse.jetty.rewrite.handler.RedirectPatternRule;
 import org.eclipse.jetty.rewrite.handler.RewriteHandler;
 import org.eclipse.jetty.server.CustomRequestLog;
+import org.eclipse.jetty.server.DetectorConnectionFactory;
 import org.eclipse.jetty.server.HttpConfiguration;
 import org.eclipse.jetty.server.HttpConnectionFactory;
-import org.eclipse.jetty.server.OptionalSslConnectionFactory;
 import org.eclipse.jetty.server.RequestLog;
 import org.eclipse.jetty.server.RequestLogWriter;
 import org.eclipse.jetty.server.SecureRequestCustomizer;
@@ -43,6 +43,8 @@ import org.qortal.api.websocket.ActiveChatsWebSocket;
 import org.qortal.api.websocket.AdminStatusWebSocket;
 import org.qortal.api.websocket.BlocksWebSocket;
 import org.qortal.api.websocket.ChatMessagesWebSocket;
+import org.qortal.api.websocket.TradeBotWebSocket;
+import org.qortal.api.websocket.TradeOffersWebSocket;
 import org.qortal.settings.Settings;
 
 public class ApiService {
@@ -113,8 +115,7 @@ public class ApiService {
 				SslConnectionFactory sslConnectionFactory = new SslConnectionFactory(sslContextFactory, HttpVersion.HTTP_1_1.asString());
 
 				ServerConnector portUnifiedConnector = new ServerConnector(this.server,
-						new OptionalSslConnectionFactory(sslConnectionFactory, HttpVersion.HTTP_1_1.asString()),
-						sslConnectionFactory,
+						new DetectorConnectionFactory(sslConnectionFactory),
 						httpConnectionFactory);
 				portUnifiedConnector.setHost(Settings.getInstance().getBindAddress());
 				portUnifiedConnector.setPort(Settings.getInstance().getApiPort());
@@ -197,6 +198,8 @@ public class ApiService {
 			context.addServlet(BlocksWebSocket.class, "/websockets/blocks");
 			context.addServlet(ActiveChatsWebSocket.class, "/websockets/chat/active/*");
 			context.addServlet(ChatMessagesWebSocket.class, "/websockets/chat/messages");
+			context.addServlet(TradeOffersWebSocket.class, "/websockets/crosschain/tradeoffers");
+			context.addServlet(TradeBotWebSocket.class, "/websockets/crosschain/tradebot");
 
 			// Start server
 			this.server.start();

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

@@ -0,0 +1,25 @@
+package org.qortal.api.model;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+
+@XmlAccessorType(XmlAccessType.FIELD)
+public class BitcoinSendRequest {
+
+	@Schema(description = "Bitcoin BIP32 extended private key", example = "tprv8ZgxMBicQKsPdahhFSrCdvC1bsWyzHHZfTneTVqUXN6s1wEtZLwAkZXzFP6TbTVGajEB55L1HYLg2aQMecZLXLre5YJcawpdFG66STVAWPJ")
+	public String xprv58;
+
+	@Schema(description = "Recipient's Bitcoin address ('legacy' P2PKH only)", example = "1BitcoinEaterAddressDontSendf59kuE")
+	public String receivingAddress;
+
+	@Schema(description = "Amount of BTC to send")
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	public long bitcoinAmount;
+
+	public BitcoinSendRequest() {
+	}
+
+}

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

@@ -0,0 +1,71 @@
+package org.qortal.api.model;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+
+import org.qortal.data.account.RewardShareData;
+import org.qortal.data.block.BlockData;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+
+@XmlAccessorType(XmlAccessType.FIELD)
+public class BlockInfo {
+
+	private byte[] signature;
+	private int height;
+	private long timestamp;
+	private int transactionCount;
+	private String minterAddress;
+
+	protected BlockInfo() {
+		/* For JAXB */
+	}
+
+	public BlockInfo(byte[] signature, int height, long timestamp, int transactionCount, String minterAddress) {
+		this.signature = signature;
+		this.height = height;
+		this.timestamp = timestamp;
+		this.transactionCount = transactionCount;
+		this.minterAddress = minterAddress;
+	}
+
+	public BlockInfo(BlockData blockData) {
+		// Convert BlockData to BlockInfo, using additional data
+		this.minterAddress = "unknown?";
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			RewardShareData rewardShareData = repository.getAccountRepository().getRewardShare(blockData.getMinterPublicKey());
+			if (rewardShareData != null)
+				this.minterAddress = rewardShareData.getMintingAccount();
+		} catch (DataException e) {
+			// We'll carry on with placeholder minterAddress then...
+		}
+
+		this.signature = blockData.getSignature();
+		this.height = blockData.getHeight();
+		this.timestamp = blockData.getTimestamp();
+		this.transactionCount = blockData.getTransactionCount();
+	}
+
+	public byte[] getSignature() {
+		return this.signature;
+	}
+
+	public int getHeight() {
+		return this.height;
+	}
+
+	public long getTimestamp() {
+		return this.timestamp;
+	}
+
+	public int getTransactionCount() {
+		return this.transactionCount;
+	}
+
+	public String getMinterAddress() {
+		return this.minterAddress;
+	}
+
+}

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

@@ -25,6 +25,9 @@ public class CrossChainBitcoinRedeemRequest {
 	@Schema(description = "32-byte secret", example = "6gVbAXCVzJXAWwtAVGAfgAkkXpeXvPUwSciPmCfSfXJG")
 	public byte[] secret;
 
+	@Schema(description = "Bitcoin HASH160(public key) for receiving funds, or omit to derive from private key", example = "u17kBVKkKSp12oUzaxFwNnq1JZf")
+	public byte[] receivingAccountInfo;
+
 	public CrossChainBitcoinRedeemRequest() {
 	}
 

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

@@ -12,20 +12,19 @@ public class CrossChainBuildRequest {
 	@Schema(description = "AT creator's public key", example = "C6wuddsBV3HzRrXUtezE7P5MoRXp5m3mEDokRDGZB6ry")
 	public byte[] creatorPublicKey;
 
-	@Schema(description = "Initial QORT amount paid when trade agreed", example = "0.00100000")
-	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
-	public long initialQortAmount;
-
 	@Schema(description = "Final QORT amount paid out on successful trade", example = "80.40200000")
 	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
-	public long finalQortAmount;
+	public long qortAmount;
 
 	@Schema(description = "QORT amount funding AT, including covering AT execution fees", example = "123.45670000")
 	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
 	public long fundingQortAmount;
 
+	@Schema(description = "HASH160 of creator's Bitcoin public key", example = "2daMveGc5pdjRyFacbxBzMksCbyC")
+	public byte[] bitcoinPublicKeyHash;
+
 	@Schema(description = "HASH160 of secret", example = "43vnftqkjxrhb5kJdkU1ZFQLEnWV")
-	public byte[] secretHash;
+	public byte[] hashOfSecretB;
 
 	@Schema(description = "Bitcoin P2SH BTC balance for release of secret", example = "0.00864200")
 	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)

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

@@ -8,10 +8,10 @@ import io.swagger.v3.oas.annotations.media.Schema;
 @XmlAccessorType(XmlAccessType.FIELD)
 public class CrossChainCancelRequest {
 
-	@Schema(description = "AT creator's public key", example = "C6wuddsBV3HzRrXUtezE7P5MoRXp5m3mEDokRDGZB6ry")
+	@Schema(description = "AT creator's public key", example = "K6wuddsBV3HzRrXFFezE7P5MoRXp5m3mEDokRDGZB6ry")
 	public byte[] creatorPublicKey;
 
-	@Schema(description = "Qortal AT address")
+	@Schema(description = "Qortal trade AT address")
 	public String atAddress;
 
 	public CrossChainCancelRequest() {

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

@@ -0,0 +1,86 @@
+package org.qortal.api.model;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
+
+import org.qortal.crosschain.BTCACCT;
+import org.qortal.data.crosschain.CrossChainTradeData;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+
+// All properties to be converted to JSON via JAXB
+@XmlAccessorType(XmlAccessType.FIELD)
+public class CrossChainOfferSummary {
+
+	// Properties
+
+	@Schema(description = "AT's Qortal address")
+	public String qortalAtAddress;
+
+	@Schema(description = "AT creator's Qortal address")
+	public String qortalCreator;
+
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long qortAmount;
+
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long btcAmount;
+
+	@Schema(description = "Suggested trade timeout (minutes)", example = "10080")
+	private int tradeTimeout;
+
+	private BTCACCT.Mode mode;
+
+	private long timestamp;
+
+	private String partnerQortalReceivingAddress;
+
+	protected CrossChainOfferSummary() {
+		/* For JAXB */
+	}
+
+	public CrossChainOfferSummary(CrossChainTradeData crossChainTradeData, long timestamp) {
+		this.qortalAtAddress = crossChainTradeData.qortalAtAddress;
+		this.qortalCreator = crossChainTradeData.qortalCreator;
+		this.qortAmount = crossChainTradeData.qortAmount;
+		this.btcAmount = crossChainTradeData.expectedBitcoin;
+		this.tradeTimeout = crossChainTradeData.tradeTimeout;
+		this.mode = crossChainTradeData.mode;
+		this.timestamp = timestamp;
+		this.partnerQortalReceivingAddress = crossChainTradeData.qortalPartnerReceivingAddress;
+	}
+
+	public String getQortalAtAddress() {
+		return this.qortalAtAddress;
+	}
+
+	public String getQortalCreator() {
+		return this.qortalCreator;
+	}
+
+	public long getQortAmount() {
+		return this.qortAmount;
+	}
+
+	public long getBtcAmount() {
+		return this.btcAmount;
+	}
+
+	public int getTradeTimeout() {
+		return this.tradeTimeout;
+	}
+
+	public BTCACCT.Mode getMode() {
+		return this.mode;
+	}
+
+	public long getTimestamp() {
+		return this.timestamp;
+	}
+
+	public String getPartnerQortalReceivingAddress() {
+		return this.partnerQortalReceivingAddress;
+	}
+
+}

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

@@ -8,14 +8,20 @@ import io.swagger.v3.oas.annotations.media.Schema;
 @XmlAccessorType(XmlAccessType.FIELD)
 public class CrossChainSecretRequest {
 
-	@Schema(description = "Public key to match AT's 'recipient'", example = "C6wuddsBV3HzRrXUtezE7P5MoRXp5m3mEDokRDGZB6ry")
-	public byte[] recipientPublicKey;
+	@Schema(description = "Public key to match AT's trade 'partner'", example = "C6wuddsBV3HzRrXUtezE7P5MoRXp5m3mEDokRDGZB6ry")
+	public byte[] partnerPublicKey;
 
 	@Schema(description = "Qortal AT address")
 	public String atAddress;
 
-	@Schema(description = "32-byte secret", example = "6gVbAXCVzJXAWwtAVGAfgAkkXpeXvPUwSciPmCfSfXJG")
-	public byte[] secret;
+	@Schema(description = "secret-A (32 bytes)", example = "FHMzten4he9jZ4HGb4297Utj6F5g2w7serjq2EnAg2s1")
+	public byte[] secretA;
+
+	@Schema(description = "secret-B (32 bytes)", example = "EN2Bgx3BcEMtxFCewmCVSMkfZjVKYhx3KEXC5A21KBGx")
+	public byte[] secretB;
+
+	@Schema(description = "Qortal address for receiving QORT from AT")
+	public String receivingAddress;
 
 	public CrossChainSecretRequest() {
 	}

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

@@ -8,14 +8,14 @@ import io.swagger.v3.oas.annotations.media.Schema;
 @XmlAccessorType(XmlAccessType.FIELD)
 public class CrossChainTradeRequest {
 
-	@Schema(description = "AT creator's public key", example = "C6wuddsBV3HzRrXUtezE7P5MoRXp5m3mEDokRDGZB6ry")
-	public byte[] creatorPublicKey;
+	@Schema(description = "AT creator's 'trade' public key", example = "C6wuddsBV3HzRrXUtezE7P5MoRXp5m3mEDokRDGZB6ry")
+	public byte[] tradePublicKey;
 
 	@Schema(description = "Qortal AT address")
 	public String atAddress;
 
-	@Schema(description = "Qortal address for trade partner/recipient")
-	public String recipient;
+	@Schema(description = "Signature of trading partner's 'offer' MESSAGE transaction")
+	public byte[] messageTransactionSignature;
 
 	public CrossChainTradeRequest() {
 	}

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

@@ -0,0 +1,43 @@
+package org.qortal.api.model;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
+
+import org.qortal.data.crosschain.CrossChainTradeData;
+
+// All properties to be converted to JSON via JAXB
+@XmlAccessorType(XmlAccessType.FIELD)
+public class CrossChainTradeSummary {
+
+	private long tradeTimestamp;
+
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long qortAmount;
+
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long btcAmount;
+
+	protected CrossChainTradeSummary() {
+		/* For JAXB */
+	}
+
+	public CrossChainTradeSummary(CrossChainTradeData crossChainTradeData, long timestamp) {
+		this.tradeTimestamp = timestamp;
+		this.qortAmount = crossChainTradeData.qortAmount;
+		this.btcAmount = crossChainTradeData.expectedBitcoin;
+	}
+
+	public long getTradeTimestamp() {
+		return this.tradeTimestamp;
+	}
+
+	public long getQortAmount() {
+		return this.qortAmount;
+	}
+
+	public long getBtcAmount() {
+		return this.btcAmount;
+	}
+
+}

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

@@ -0,0 +1,36 @@
+package org.qortal.api.model;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+
+@XmlAccessorType(XmlAccessType.FIELD)
+public class TradeBotCreateRequest {
+
+	@Schema(description = "Trade creator's public key", example = "2zR1WFsbM7akHghqSCYKBPk6LDP8aKiQSRS1FrwoLvoB")
+	public byte[] creatorPublicKey;
+
+	@Schema(description = "QORT amount paid out on successful trade", example = "80.40200000")
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	public long qortAmount;
+
+	@Schema(description = "QORT amount funding AT, including covering AT execution fees", example = "81")
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	public long fundingQortAmount;
+
+	@Schema(description = "Bitcoin amount wanted in return", example = "0.00864200")
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	public long bitcoinAmount;
+
+	@Schema(description = "Suggested trade timeout (minutes)", example = "10080")
+	public int tradeTimeout;
+
+	@Schema(description = "Bitcoin address for receiving", example = "1BitcoinEaterAddressDontSendf59kuE")
+	public String receivingAddress;
+
+	public TradeBotCreateRequest() {
+	}
+
+}

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

@@ -0,0 +1,23 @@
+package org.qortal.api.model;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+
+@XmlAccessorType(XmlAccessType.FIELD)
+public class TradeBotRespondRequest {
+
+	@Schema(description = "Qortal AT address", example = "AH3e3jHEsGHPVQPDiJx4pYqgVi72auxgVy")
+	public String atAddress;
+
+	@Schema(description = "Bitcoin BIP32 extended private key", example = "tprv8ZgxMBicQKsPdahhFSrCdvC1bsWyzHHZfTneTVqUXN6s1wEtZLwAkZXzFP6TbTVGajEB55L1HYLg2aQMecZLXLre5YJcawpdFG66STVAWPJ")
+	public String xprv58;
+
+	@Schema(description = "Qortal address for receiving QORT from AT")
+	public String receivingAddress;
+
+	public TradeBotRespondRequest() {
+	}
+
+}

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

@@ -302,13 +302,13 @@ public class AdminResource {
 	@DELETE
 	@Path("/mintingaccounts")
 	@Operation(
-		summary = "Remove account/reward-share from use by BlockMinter, using private key",
+		summary = "Remove account/reward-share from use by BlockMinter, using public or private key",
 		requestBody = @RequestBody(
 			required = true,
 			content = @Content(
 				mediaType = MediaType.TEXT_PLAIN,
 				schema = @Schema(
-					type = "string", example = "private key"
+					type = "string", example = "public or private key"
 				)
 			)
 		),
@@ -319,13 +319,13 @@ public class AdminResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_PRIVATE_KEY, ApiError.REPOSITORY_ISSUE})
-	public String deleteMintingAccount(String seed58) {
+	public String deleteMintingAccount(String key58) {
 		Security.checkApiCallAllowed(request);
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			byte[] seed = Base58.decode(seed58.trim());
+			byte[] key = Base58.decode(key58.trim());
 
-			if (repository.getAccountRepository().delete(seed) == 0)
+			if (repository.getAccountRepository().delete(key) == 0)
 				return "false";
 
 			repository.saveChanges();

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

@@ -25,7 +25,6 @@ import org.qortal.api.ApiError;
 import org.qortal.api.ApiErrors;
 import org.qortal.api.ApiException;
 import org.qortal.api.ApiExceptionFactory;
-import org.qortal.at.QortalAtLoggerFactory;
 import org.qortal.data.at.ATData;
 import org.qortal.data.at.ATStateData;
 import org.qortal.data.transaction.DeployAtTransactionData;
@@ -147,8 +146,7 @@ public class AtResource {
 			ATStateData atStateData = repository.getATRepository().getLatestATState(atAddress);
 			byte[] stateData = atStateData.getStateData();
 
-			QortalAtLoggerFactory loggerFactory = QortalAtLoggerFactory.getInstance();
-			byte[] dataBytes = MachineState.extractDataBytes(loggerFactory, stateData);
+			byte[] dataBytes = MachineState.extractDataBytes(stateData);
 
 			return dataBytes;
 		} catch (ApiException e) {

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

@@ -23,6 +23,7 @@ import javax.ws.rs.core.MediaType;
 import org.qortal.api.ApiError;
 import org.qortal.api.ApiErrors;
 import org.qortal.api.ApiExceptionFactory;
+import org.qortal.api.model.BlockInfo;
 import org.qortal.api.model.BlockSignerSummary;
 import org.qortal.crypto.Crypto;
 import org.qortal.data.account.AccountData;
@@ -480,4 +481,44 @@ public class BlocksResource {
 		}
 	}
 
+	@GET
+	@Path("/summaries")
+	@Operation(
+		summary = "Fetch only summary info about a range of blocks",
+		description = "Specify up to 2 out 3 of: start, end and count. If neither start nor end are specified, then end is assumed to be latest block. Where necessary, count is assumed to be 50.",
+		responses = {
+			@ApiResponse(
+				description = "blocks",
+				content = @Content(
+					array = @ArraySchema(
+						schema = @Schema(
+							implementation = BlockInfo.class
+						)
+					)
+				)
+			)
+		}
+	)
+	@ApiErrors({
+		ApiError.REPOSITORY_ISSUE
+	})
+	public List<BlockInfo> getBlockRange(
+			@QueryParam("start") Integer startHeight,
+			@QueryParam("end") Integer endHeight,
+			@Parameter(ref = "count") @QueryParam("count") Integer count) {
+		// Check up to 2 out of 3 params
+		if (startHeight != null && endHeight != null && count != null)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+		// Check values
+		if ((startHeight != null && startHeight < 1) || (endHeight != null && endHeight < 1) || (count != null && count < 1))
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			return repository.getBlockRepository().getBlockInfos(startHeight, endHeight, count);
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
 }

src/main/java/org/qortal/api/websocket/ActiveChatsWebSocket.java

@@ -6,11 +6,12 @@ import java.util.Map;
 import java.util.concurrent.atomic.AtomicReference;
 
 import org.eclipse.jetty.websocket.api.Session;
+import org.eclipse.jetty.websocket.api.WebSocketException;
 import org.eclipse.jetty.websocket.api.annotations.OnWebSocketClose;
 import org.eclipse.jetty.websocket.api.annotations.OnWebSocketConnect;
+import org.eclipse.jetty.websocket.api.annotations.OnWebSocketError;
 import org.eclipse.jetty.websocket.api.annotations.OnWebSocketMessage;
 import org.eclipse.jetty.websocket.api.annotations.WebSocket;
-import org.eclipse.jetty.websocket.servlet.WebSocketServlet;
 import org.eclipse.jetty.websocket.servlet.WebSocketServletFactory;
 import org.qortal.controller.ChatNotifier;
 import org.qortal.crypto.Crypto;
@@ -22,7 +23,7 @@ import org.qortal.repository.RepositoryManager;
 
 @WebSocket
 @SuppressWarnings("serial")
-public class ActiveChatsWebSocket extends WebSocketServlet implements ApiWebSocket {
+public class ActiveChatsWebSocket extends ApiWebSocket {
 
 	@Override
 	public void configure(WebSocketServletFactory factory) {
@@ -31,7 +32,7 @@ public class ActiveChatsWebSocket extends WebSocketServlet implements ApiWebSock
 
 	@OnWebSocketConnect
 	public void onWebSocketConnect(Session session) {
-		Map<String, String> pathParams = this.getPathParams(session, "/{address}");
+		Map<String, String> pathParams = getPathParams(session, "/{address}");
 
 		String address = pathParams.get("address");
 		if (address == null || !Crypto.isValidAddress(address)) {
@@ -52,6 +53,10 @@ public class ActiveChatsWebSocket extends WebSocketServlet implements ApiWebSock
 		ChatNotifier.getInstance().deregister(session);
 	}
 
+	@OnWebSocketError
+	public void onWebSocketError(Session session, Throwable throwable) {
+	}
+
 	@OnWebSocketMessage
 	public void onWebSocketMessage(Session session, String message) {
 	}
@@ -70,7 +75,7 @@ public class ActiveChatsWebSocket extends WebSocketServlet implements ApiWebSock
 
 			StringWriter stringWriter = new StringWriter();
 
-			this.marshall(stringWriter, activeChats);
+			marshall(stringWriter, activeChats);
 
 			// Only output if something has changed
 			String output = stringWriter.toString();
@@ -78,8 +83,8 @@ public class ActiveChatsWebSocket extends WebSocketServlet implements ApiWebSock
 				return;
 
 			previousOutput.set(output);
-			session.getRemote().sendString(output);
-		} catch (DataException | IOException e) {
+			session.getRemote().sendStringByFuture(output);
+		} catch (DataException | IOException | WebSocketException e) {
 			// No output this time?
 		}
 	}

src/main/java/org/qortal/api/websocket/AdminStatusWebSocket.java

@@ -5,11 +5,12 @@ import java.io.StringWriter;
 import java.util.concurrent.atomic.AtomicReference;
 
 import org.eclipse.jetty.websocket.api.Session;
+import org.eclipse.jetty.websocket.api.WebSocketException;
 import org.eclipse.jetty.websocket.api.annotations.OnWebSocketClose;
 import org.eclipse.jetty.websocket.api.annotations.OnWebSocketConnect;
+import org.eclipse.jetty.websocket.api.annotations.OnWebSocketError;
 import org.eclipse.jetty.websocket.api.annotations.OnWebSocketMessage;
 import org.eclipse.jetty.websocket.api.annotations.WebSocket;
-import org.eclipse.jetty.websocket.servlet.WebSocketServlet;
 import org.eclipse.jetty.websocket.servlet.WebSocketServletFactory;
 import org.qortal.api.model.NodeStatus;
 import org.qortal.controller.StatusNotifier;
@@ -19,7 +20,7 @@ import org.qortal.repository.RepositoryManager;
 
 @WebSocket
 @SuppressWarnings("serial")
-public class AdminStatusWebSocket extends WebSocketServlet implements ApiWebSocket {
+public class AdminStatusWebSocket extends ApiWebSocket {
 
 	@Override
 	public void configure(WebSocketServletFactory factory) {
@@ -41,6 +42,10 @@ public class AdminStatusWebSocket extends WebSocketServlet implements ApiWebSock
 		StatusNotifier.getInstance().deregister(session);
 	}
 
+	@OnWebSocketError
+	public void onWebSocketError(Session session, Throwable throwable) {
+	}
+
 	@OnWebSocketMessage
 	public void onWebSocketMessage(Session session, String message) {
 	}
@@ -51,7 +56,7 @@ public class AdminStatusWebSocket extends WebSocketServlet implements ApiWebSock
 
 			StringWriter stringWriter = new StringWriter();
 
-			this.marshall(stringWriter, nodeStatus);
+			marshall(stringWriter, nodeStatus);
 
 			// Only output if something has changed
 			String output = stringWriter.toString();
@@ -59,8 +64,8 @@ public class AdminStatusWebSocket extends WebSocketServlet implements ApiWebSock
 				return;
 
 			previousOutput.set(output);
-			session.getRemote().sendString(output);
-		} catch (DataException | IOException e) {
+			session.getRemote().sendStringByFuture(output);
+		} catch (DataException | IOException | WebSocketException e) {
 			// No output this time?
 		}
 	}

src/main/java/org/qortal/api/websocket/ApiWebSocket.java

@@ -3,7 +3,10 @@ package org.qortal.api.websocket;
 import java.io.IOException;
 import java.io.StringWriter;
 import java.io.Writer;
+import java.util.ArrayList;
 import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import javax.xml.bind.JAXBContext;
@@ -13,24 +16,28 @@ import javax.xml.bind.Marshaller;
 import org.eclipse.jetty.http.pathmap.UriTemplatePathSpec;
 import org.eclipse.jetty.websocket.api.Session;
 import org.eclipse.jetty.websocket.servlet.ServletUpgradeRequest;
+import org.eclipse.jetty.websocket.servlet.WebSocketServlet;
 import org.eclipse.persistence.jaxb.JAXBContextFactory;
 import org.eclipse.persistence.jaxb.MarshallerProperties;
 import org.qortal.api.ApiError;
 import org.qortal.api.ApiErrorRoot;
 
-interface ApiWebSocket {
+@SuppressWarnings("serial")
+abstract class ApiWebSocket extends WebSocketServlet {
 
-	default String getPathInfo(Session session) {
+	private static final Map<Class<? extends ApiWebSocket>, List<Session>> SESSIONS_BY_CLASS = new HashMap<>();
+
+	protected static String getPathInfo(Session session) {
 		ServletUpgradeRequest upgradeRequest = (ServletUpgradeRequest) session.getUpgradeRequest();
 		return upgradeRequest.getHttpServletRequest().getPathInfo();
 	}
 
-	default Map<String, String> getPathParams(Session session, String pathSpec) {
+	protected static Map<String, String> getPathParams(Session session, String pathSpec) {
 		UriTemplatePathSpec uriTemplatePathSpec = new UriTemplatePathSpec(pathSpec);
-		return uriTemplatePathSpec.getPathParams(this.getPathInfo(session));
+		return uriTemplatePathSpec.getPathParams(getPathInfo(session));
 	}
 
-	default void sendError(Session session, ApiError apiError) {
+	protected static void sendError(Session session, ApiError apiError) {
 		ApiErrorRoot apiErrorRoot = new ApiErrorRoot();
 		apiErrorRoot.setApiError(apiError);
 
@@ -43,7 +50,7 @@ interface ApiWebSocket {
 		}
 	}
 
-	default void marshall(Writer writer, Object object) throws IOException {
+	protected static void marshall(Writer writer, Object object) throws IOException {
 		Marshaller marshaller = createMarshaller(object.getClass());
 
 		try {
@@ -53,7 +60,7 @@ interface ApiWebSocket {
 		}
 	}
 
-	default void marshall(Writer writer, Collection<?> collection) throws IOException {
+	protected static void marshall(Writer writer, Collection<?> collection) throws IOException {
 		// If collection is empty then we're returning "[]" anyway
 		if (collection.isEmpty()) {
 			writer.append("[]");
@@ -92,4 +99,22 @@ interface ApiWebSocket {
 		}
 	}
 
+	public void onWebSocketConnect(Session session) {
+		synchronized (SESSIONS_BY_CLASS) {
+			SESSIONS_BY_CLASS.computeIfAbsent(this.getClass(), clazz -> new ArrayList<>()).add(session);
+		}
+	}
+
+	public void onWebSocketClose(Session session, int statusCode, String reason) {
+		synchronized (SESSIONS_BY_CLASS) {
+			SESSIONS_BY_CLASS.get(this.getClass()).remove(session);
+		}
+	}
+
+	protected List<Session> getSessions() {
+		synchronized (SESSIONS_BY_CLASS) {
+			return new ArrayList<>(SESSIONS_BY_CLASS.get(this.getClass()));
+		}
+	}
+
 }

src/main/java/org/qortal/api/websocket/BlocksWebSocket.java

@@ -2,17 +2,19 @@ package org.qortal.api.websocket;
 
 import java.io.IOException;
 import java.io.StringWriter;
+import java.util.List;
 
 import org.eclipse.jetty.websocket.api.Session;
+import org.eclipse.jetty.websocket.api.WebSocketException;
 import org.eclipse.jetty.websocket.api.annotations.OnWebSocketClose;
 import org.eclipse.jetty.websocket.api.annotations.OnWebSocketConnect;
+import org.eclipse.jetty.websocket.api.annotations.OnWebSocketError;
 import org.eclipse.jetty.websocket.api.annotations.OnWebSocketMessage;
 import org.eclipse.jetty.websocket.api.annotations.WebSocket;
-import org.eclipse.jetty.websocket.servlet.WebSocketServlet;
 import org.eclipse.jetty.websocket.servlet.WebSocketServletFactory;
 import org.qortal.api.ApiError;
+import org.qortal.api.model.BlockInfo;
 import org.qortal.controller.BlockNotifier;
-import org.qortal.data.block.BlockData;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
 import org.qortal.repository.RepositoryManager;
@@ -20,7 +22,7 @@ import org.qortal.utils.Base58;
 
 @WebSocket
 @SuppressWarnings("serial")
-public class BlocksWebSocket extends WebSocketServlet implements ApiWebSocket {
+public class BlocksWebSocket extends ApiWebSocket {
 
 	@Override
 	public void configure(WebSocketServletFactory factory) {
@@ -29,7 +31,7 @@ public class BlocksWebSocket extends WebSocketServlet implements ApiWebSocket {
 
 	@OnWebSocketConnect
 	public void onWebSocketConnect(Session session) {
-		BlockNotifier.Listener listener = blockData -> onNotify(session, blockData);
+		BlockNotifier.Listener listener = blockInfo -> onNotify(session, blockInfo);
 		BlockNotifier.getInstance().register(session, listener);
 	}
 
@@ -38,6 +40,10 @@ public class BlocksWebSocket extends WebSocketServlet implements ApiWebSocket {
 		BlockNotifier.getInstance().deregister(session);
 	}
 
+	@OnWebSocketError
+	public void onWebSocketError(Session session, Throwable throwable) {
+	}
+
 	@OnWebSocketMessage
 	public void onWebSocketMessage(Session session, String message) {
 		// We're expecting either a base58 block signature or an integer block height
@@ -53,13 +59,19 @@ public class BlocksWebSocket extends WebSocketServlet implements ApiWebSocket {
 			}
 
 			try (final Repository repository = RepositoryManager.getRepository()) {
-				BlockData blockData = repository.getBlockRepository().fromSignature(signature);
-				if (blockData == null) {
+				int height = repository.getBlockRepository().getHeightFromSignature(signature);
+				if (height == 0) {
 					sendError(session, ApiError.BLOCK_UNKNOWN);
 					return;
 				}
 
-				onNotify(session, blockData);
+				List<BlockInfo> blockInfos = repository.getBlockRepository().getBlockInfos(height, null, 1);
+				if (blockInfos == null || blockInfos.isEmpty()) {
+					sendError(session, ApiError.BLOCK_UNKNOWN);
+					return;
+				}
+
+				onNotify(session, blockInfos.get(0));
 			} catch (DataException e) {
 				sendError(session, ApiError.REPOSITORY_ISSUE);
 			}
@@ -82,26 +94,26 @@ public class BlocksWebSocket extends WebSocketServlet implements ApiWebSocket {
 		}
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			BlockData blockData = repository.getBlockRepository().fromHeight(height);
-			if (blockData == null) {
+			List<BlockInfo> blockInfos = repository.getBlockRepository().getBlockInfos(height, null, 1);
+			if (blockInfos == null || blockInfos.isEmpty()) {
 				sendError(session, ApiError.BLOCK_UNKNOWN);
 				return;
 			}
 
-			onNotify(session, blockData);
+			onNotify(session, blockInfos.get(0));
 		} catch (DataException e) {
 			sendError(session, ApiError.REPOSITORY_ISSUE);
 		}
 	}
 
-	private void onNotify(Session session, BlockData blockData) {
+	private void onNotify(Session session, BlockInfo blockInfo) {
 		StringWriter stringWriter = new StringWriter();
 
 		try {
-			this.marshall(stringWriter, blockData);
+			marshall(stringWriter, blockInfo);
 
-			session.getRemote().sendString(stringWriter.toString());
-		} catch (IOException e) {
+			session.getRemote().sendStringByFuture(stringWriter.toString());
+		} catch (IOException | WebSocketException e) {
 			// No output this time
 		}
 	}

src/main/java/org/qortal/api/websocket/ChatMessagesWebSocket.java

@@ -8,11 +8,12 @@ import java.util.List;
 import java.util.Map;
 
 import org.eclipse.jetty.websocket.api.Session;
+import org.eclipse.jetty.websocket.api.WebSocketException;
 import org.eclipse.jetty.websocket.api.annotations.OnWebSocketClose;
 import org.eclipse.jetty.websocket.api.annotations.OnWebSocketConnect;
+import org.eclipse.jetty.websocket.api.annotations.OnWebSocketError;
 import org.eclipse.jetty.websocket.api.annotations.OnWebSocketMessage;
 import org.eclipse.jetty.websocket.api.annotations.WebSocket;
-import org.eclipse.jetty.websocket.servlet.WebSocketServlet;
 import org.eclipse.jetty.websocket.servlet.WebSocketServletFactory;
 import org.qortal.controller.ChatNotifier;
 import org.qortal.data.chat.ChatMessage;
@@ -23,7 +24,7 @@ import org.qortal.repository.RepositoryManager;
 
 @WebSocket
 @SuppressWarnings("serial")
-public class ChatMessagesWebSocket extends WebSocketServlet implements ApiWebSocket {
+public class ChatMessagesWebSocket extends ApiWebSocket {
 
 	@Override
 	public void configure(WebSocketServletFactory factory) {
@@ -89,6 +90,10 @@ public class ChatMessagesWebSocket extends WebSocketServlet implements ApiWebSoc
 		ChatNotifier.getInstance().deregister(session);
 	}
 
+	@OnWebSocketError
+	public void onWebSocketError(Session session, Throwable throwable) {
+	}
+
 	@OnWebSocketMessage
 	public void onWebSocketMessage(Session session, String message) {
 	}
@@ -123,10 +128,10 @@ public class ChatMessagesWebSocket extends WebSocketServlet implements ApiWebSoc
 		StringWriter stringWriter = new StringWriter();
 
 		try {
-			this.marshall(stringWriter, chatMessages);
+			marshall(stringWriter, chatMessages);
 
-			session.getRemote().sendString(stringWriter.toString());
-		} catch (IOException e) {
+			session.getRemote().sendStringByFuture(stringWriter.toString());
+		} catch (IOException | WebSocketException e) {
 			// No output this time?
 		}
 	}

src/main/java/org/qortal/api/websocket/TradeBotWebSocket.java

@@ -0,0 +1,119 @@
+package org.qortal.api.websocket;
+
+import java.io.IOException;
+import java.io.StringWriter;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import org.eclipse.jetty.websocket.api.Session;
+import org.eclipse.jetty.websocket.api.annotations.OnWebSocketClose;
+import org.eclipse.jetty.websocket.api.annotations.OnWebSocketConnect;
+import org.eclipse.jetty.websocket.api.annotations.OnWebSocketMessage;
+import org.eclipse.jetty.websocket.api.annotations.WebSocket;
+import org.eclipse.jetty.websocket.servlet.WebSocketServletFactory;
+import org.qortal.controller.TradeBot;
+import org.qortal.data.crosschain.TradeBotData;
+import org.qortal.event.Event;
+import org.qortal.event.EventBus;
+import org.qortal.event.Listener;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+import org.qortal.utils.Base58;
+
+@WebSocket
+@SuppressWarnings("serial")
+public class TradeBotWebSocket extends ApiWebSocket implements Listener {
+
+	/** Cache of trade-bot entry states, keyed by trade-bot entry's "trade private key" (base58) */
+	private static final Map<String, TradeBotData.State> PREVIOUS_STATES = new HashMap<>();
+
+	@Override
+	public void configure(WebSocketServletFactory factory) {
+		factory.register(TradeBotWebSocket.class);
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			List<TradeBotData> tradeBotEntries = repository.getCrossChainRepository().getAllTradeBotData();
+			if (tradeBotEntries == null)
+				// How do we properly fail here?
+				return;
+
+			PREVIOUS_STATES.putAll(tradeBotEntries.stream().collect(Collectors.toMap(entry -> Base58.encode(entry.getTradePrivateKey()), TradeBotData::getState)));
+		} catch (DataException e) {
+			// No output this time
+		}
+
+		EventBus.INSTANCE.addListener(this::listen);
+	}
+
+	@Override
+	public void listen(Event event) {
+		if (!(event instanceof TradeBot.StateChangeEvent))
+			return;
+
+		TradeBotData tradeBotData = ((TradeBot.StateChangeEvent) event).getTradeBotData();
+		String tradePrivateKey58 = Base58.encode(tradeBotData.getTradePrivateKey());
+
+		synchronized (PREVIOUS_STATES) {
+			if (PREVIOUS_STATES.get(tradePrivateKey58) == tradeBotData.getState())
+				// Not changed
+				return;
+
+			PREVIOUS_STATES.put(tradePrivateKey58, tradeBotData.getState());
+		}
+
+		List<TradeBotData> tradeBotEntries = Collections.singletonList(tradeBotData);
+		for (Session session : getSessions())
+			sendEntries(session, tradeBotEntries);
+	}
+
+	@OnWebSocketConnect
+	public void onWebSocketConnect(Session session) {
+		// Send all known trade-bot entries
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			List<TradeBotData> tradeBotEntries = repository.getCrossChainRepository().getAllTradeBotData();
+			if (tradeBotEntries == null) {
+				session.close(4001, "repository issue fetching trade-bot entries");
+				return;
+			}
+
+			if (!sendEntries(session, tradeBotEntries)) {
+				session.close(4002, "websocket issue");
+				return;
+			}
+		} catch (DataException e) {
+			// No output this time
+		}
+
+		super.onWebSocketConnect(session);
+	}
+
+	@OnWebSocketClose
+	public void onWebSocketClose(Session session, int statusCode, String reason) {
+		super.onWebSocketClose(session, statusCode, reason);
+	}
+
+	@OnWebSocketMessage
+	public void onWebSocketMessage(Session session, String message) {
+		/* ignored */
+	}
+
+	private boolean sendEntries(Session session, List<TradeBotData> tradeBotEntries) {
+		try {
+			StringWriter stringWriter = new StringWriter();
+			marshall(stringWriter, tradeBotEntries);
+
+			String output = stringWriter.toString();
+			session.getRemote().sendStringByFuture(output);
+		} catch (IOException e) {
+			// No output this time?
+			return false;
+		}
+
+		return true;
+	}
+
+}

src/main/java/org/qortal/api/websocket/TradeOffersWebSocket.java

@@ -0,0 +1,212 @@
+package org.qortal.api.websocket;
+
+import java.io.IOException;
+import java.io.StringWriter;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import org.eclipse.jetty.websocket.api.Session;
+import org.eclipse.jetty.websocket.api.annotations.OnWebSocketClose;
+import org.eclipse.jetty.websocket.api.annotations.OnWebSocketConnect;
+import org.eclipse.jetty.websocket.api.annotations.OnWebSocketMessage;
+import org.eclipse.jetty.websocket.api.annotations.WebSocket;
+import org.eclipse.jetty.websocket.servlet.WebSocketServletFactory;
+import org.qortal.api.model.BlockInfo;
+import org.qortal.api.model.CrossChainOfferSummary;
+import org.qortal.controller.BlockNotifier;
+import org.qortal.crosschain.BTCACCT;
+import org.qortal.data.at.ATStateData;
+import org.qortal.data.crosschain.CrossChainTradeData;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+import org.qortal.utils.NTP;
+
+@WebSocket
+@SuppressWarnings("serial")
+public class TradeOffersWebSocket extends ApiWebSocket {
+
+	@Override
+	public void configure(WebSocketServletFactory factory) {
+		factory.register(TradeOffersWebSocket.class);
+	}
+
+	@OnWebSocketConnect
+	public void onWebSocketConnect(Session session) {
+		Map<String, List<String>> queryParams = session.getUpgradeRequest().getParameterMap();
+
+		final boolean includeHistoric = queryParams.get("includeHistoric") != null;
+		final Map<String, BTCACCT.Mode> previousAtModes = new HashMap<>();
+		List<CrossChainOfferSummary> crossChainOfferSummaries;
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			List<ATStateData> initialAtStates;
+
+			// We want ALL OFFERING trades
+			Boolean isFinished = Boolean.FALSE;
+			Integer dataByteOffset = BTCACCT.MODE_BYTE_OFFSET;
+			Long expectedValue = (long) BTCACCT.Mode.OFFERING.value;
+			Integer minimumFinalHeight = null;
+
+			initialAtStates = repository.getATRepository().getMatchingFinalATStates(BTCACCT.CODE_BYTES_HASH,
+					isFinished, dataByteOffset, expectedValue, minimumFinalHeight,
+					null, null, null);
+
+			if (initialAtStates == null) {
+				session.close(4001, "repository issue fetching OFFERING trades");
+				return;
+			}
+
+			// Save initial AT modes
+			previousAtModes.putAll(initialAtStates.stream().collect(Collectors.toMap(ATStateData::getATAddress, atState -> BTCACCT.Mode.OFFERING)));
+
+			// Convert to offer summaries
+			crossChainOfferSummaries = produceSummaries(repository, initialAtStates, null);
+
+			if (includeHistoric) {
+				// We also want REDEEMED/REFUNDED/CANCELLED trades over the last 24 hours
+				long timestamp = NTP.getTime() - 24 * 60 * 60 * 1000L;
+				minimumFinalHeight = repository.getBlockRepository().getHeightFromTimestamp(timestamp);
+
+				if (minimumFinalHeight != 0) {
+					isFinished = Boolean.TRUE;
+					dataByteOffset = null;
+					expectedValue = null;
+					++minimumFinalHeight; // because height is just *before* timestamp
+
+					List<ATStateData> historicAtStates = repository.getATRepository().getMatchingFinalATStates(BTCACCT.CODE_BYTES_HASH,
+							isFinished, dataByteOffset, expectedValue, minimumFinalHeight,
+							null, null, null);
+
+					if (historicAtStates == null) {
+						session.close(4002, "repository issue fetching historic trades");
+						return;
+					}
+
+					for (ATStateData historicAtState : historicAtStates) {
+						CrossChainOfferSummary historicOfferSummary = produceSummary(repository, historicAtState, null);
+
+						switch (historicOfferSummary.getMode()) {
+							case REDEEMED:
+							case REFUNDED:
+							case CANCELLED:
+								break;
+
+							default:
+								continue;
+						}
+
+						// Add summary to initial burst
+						crossChainOfferSummaries.add(historicOfferSummary);
+
+						// Save initial AT mode
+						previousAtModes.put(historicAtState.getATAddress(), historicOfferSummary.getMode());
+					}
+				}
+			}
+
+		} catch (DataException e) {
+			session.close(4003, "generic repository issue");
+			return;
+		}
+
+		if (!sendOfferSummaries(session, crossChainOfferSummaries)) {
+			session.close(4004, "websocket issue");
+			return;
+		}
+
+		BlockNotifier.Listener listener = blockInfo -> onNotify(session, blockInfo, previousAtModes);
+		BlockNotifier.getInstance().register(session, listener);
+	}
+
+	@OnWebSocketClose
+	public void onWebSocketClose(Session session, int statusCode, String reason) {
+		BlockNotifier.getInstance().deregister(session);
+	}
+
+	@OnWebSocketMessage
+	public void onWebSocketMessage(Session session, String message) {
+		/* ignored */
+	}
+
+	private void onNotify(Session session, BlockInfo blockInfo, final Map<String, BTCACCT.Mode> previousAtModes) {
+		List<CrossChainOfferSummary> crossChainOfferSummaries = null;
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			// Find any new trade ATs since this block
+			final Boolean isFinished = null;
+			final Integer dataByteOffset = null;
+			final Long expectedValue = null;
+			final Integer minimumFinalHeight = blockInfo.getHeight();
+
+			List<ATStateData> atStates = repository.getATRepository().getMatchingFinalATStates(BTCACCT.CODE_BYTES_HASH,
+					isFinished, dataByteOffset, expectedValue, minimumFinalHeight,
+					null, null, null);
+
+			if (atStates == null)
+				return;
+
+			crossChainOfferSummaries = produceSummaries(repository, atStates, blockInfo.getTimestamp());
+		} catch (DataException e) {
+			// No output this time
+		}
+
+		synchronized (previousAtModes) { //NOSONAR squid:S2445 suppressed because previousAtModes is final and curried in lambda
+			// Remove any entries unchanged from last time
+			crossChainOfferSummaries.removeIf(offerSummary -> previousAtModes.get(offerSummary.getQortalAtAddress()) == offerSummary.getMode());
+
+			// Don't send anything if no results
+			if (crossChainOfferSummaries.isEmpty())
+				return;
+
+			final boolean wasSent = sendOfferSummaries(session, crossChainOfferSummaries);
+
+			if (!wasSent)
+				return;
+
+			previousAtModes.putAll(crossChainOfferSummaries.stream().collect(Collectors.toMap(CrossChainOfferSummary::getQortalAtAddress, CrossChainOfferSummary::getMode)));
+		}
+	}
+
+	private boolean sendOfferSummaries(Session session, List<CrossChainOfferSummary> crossChainOfferSummaries) {
+		try {
+			StringWriter stringWriter = new StringWriter();
+			marshall(stringWriter, crossChainOfferSummaries);
+
+			String output = stringWriter.toString();
+			session.getRemote().sendStringByFuture(output);
+		} catch (IOException e) {
+			// No output this time?
+			return false;
+		}
+
+		return true;
+	}
+
+	private static CrossChainOfferSummary produceSummary(Repository repository, ATStateData atState, Long timestamp) throws DataException {
+		CrossChainTradeData crossChainTradeData = BTCACCT.populateTradeData(repository, atState);
+
+		long atStateTimestamp;
+
+		if (crossChainTradeData.mode == BTCACCT.Mode.OFFERING)
+			// We want when trade was created, not when it was last updated
+			atStateTimestamp = atState.getCreation();
+		else
+			atStateTimestamp = timestamp != null ? timestamp : repository.getBlockRepository().getTimestampFromHeight(atState.getHeight());
+
+		return new CrossChainOfferSummary(crossChainTradeData, atStateTimestamp);
+	}
+
+	private static List<CrossChainOfferSummary> produceSummaries(Repository repository, List<ATStateData> atStates, Long timestamp) throws DataException {
+		List<CrossChainOfferSummary> offerSummaries = new ArrayList<>();
+
+		for (ATStateData atState : atStates)
+			offerSummaries.add(produceSummary(repository, atState, timestamp));
+
+		return offerSummaries;
+	}
+
+}

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

@@ -117,12 +117,8 @@ public class AT {
 	}
 
 	public void update(int blockHeight, long blockTimestamp) throws DataException {
-		// [Re]create AT machine state using AT state data or from scratch as applicable
-		QortalATAPI api = new QortalATAPI(repository, this.atData, blockTimestamp);
-		QortalAtLoggerFactory loggerFactory = QortalAtLoggerFactory.getInstance();
-
-		byte[] codeBytes = this.atData.getCodeBytes();
-		MachineState state = MachineState.fromBytes(api, loggerFactory, this.atStateData.getStateData(), codeBytes);
+		// Extract minimal/flags-only AT machine state using AT state data
+		MachineState state = MachineState.flagsOnlyfromBytes(this.atStateData.getStateData());
 
 		// Save latest AT state data
 		this.repository.getATRepository().save(this.atStateData);
@@ -151,12 +147,8 @@ public class AT {
 		if (previousStateData == null)
 			throw new DataException("Can't find previous AT state data for " + atAddress);
 
-		// [Re]create AT machine state using AT state data or from scratch as applicable
-		QortalATAPI api = new QortalATAPI(repository, this.atData, blockTimestamp);
-		QortalAtLoggerFactory loggerFactory = QortalAtLoggerFactory.getInstance();
-
-		byte[] codeBytes = this.atData.getCodeBytes();
-		MachineState state = MachineState.fromBytes(api, loggerFactory, previousStateData.getStateData(), codeBytes);
+		// Extract minimal/flags-only AT machine state using AT state data
+		MachineState state = MachineState.flagsOnlyfromBytes(previousStateData.getStateData());
 
 		// Update AT info in repository
 		this.atData.setIsSleeping(state.isSleeping());

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

@@ -17,7 +17,6 @@ import org.qortal.account.Account;
 import org.qortal.account.NullAccount;
 import org.qortal.account.PublicKeyAccount;
 import org.qortal.asset.Asset;
-import org.qortal.block.Block;
 import org.qortal.block.BlockChain;
 import org.qortal.block.BlockChain.CiyamAtSettings;
 import org.qortal.crypto.Crypto;
@@ -30,13 +29,13 @@ import org.qortal.data.transaction.MessageTransactionData;
 import org.qortal.data.transaction.PaymentTransactionData;
 import org.qortal.data.transaction.TransactionData;
 import org.qortal.group.Group;
-import org.qortal.repository.BlockRepository;
+import org.qortal.repository.ATRepository;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
 import org.qortal.transaction.AtTransaction;
-import org.qortal.transaction.Transaction;
 import org.qortal.transaction.Transaction.TransactionType;
 import org.qortal.utils.Base58;
+import org.qortal.utils.BitTwiddling;
 
 import com.google.common.primitives.Bytes;
 
@@ -133,9 +132,9 @@ public class QortalATAPI extends API {
 
 			byte[] signature = blockSummaries.get(0).getSignature();
 			// Save some of minter's signature and transactions signature, so middle 24 bytes of the full 128 byte signature.
-			this.setA2(state, fromBytes(signature, 52));
-			this.setA3(state, fromBytes(signature, 60));
-			this.setA4(state, fromBytes(signature, 68));
+			this.setA2(state, BitTwiddling.longFromBEBytes(signature, 52));
+			this.setA3(state, BitTwiddling.longFromBEBytes(signature, 60));
+			this.setA4(state, BitTwiddling.longFromBEBytes(signature, 68));
 		} catch (DataException e) {
 			throw new RuntimeException("AT API unable to fetch previous block?", e);
 		}
@@ -149,59 +148,27 @@ public class QortalATAPI extends API {
 		int height = timestamp.blockHeight;
 		int sequence = timestamp.transactionSequence + 1;
 
-		BlockRepository blockRepository = this.getRepository().getBlockRepository();
-
+		ATRepository.NextTransactionInfo nextTransactionInfo;
 		try {
-			int currentHeight = blockRepository.getBlockchainHeight();
-			List<Transaction> blockTransactions = null;
-
-			while (height <= currentHeight) {
-				if (blockTransactions == null) {
-					BlockData blockData = blockRepository.fromHeight(height);
-
-					if (blockData == null)
-						throw new DataException("Unable to fetch block " + height + " from repository?");
-
-					Block block = new Block(this.getRepository(), blockData);
-
-					blockTransactions = block.getTransactions();
-				}
-
-				// No more transactions in this block? Try next block
-				if (sequence >= blockTransactions.size()) {
-					++height;
-					sequence = 0;
-					blockTransactions = null;
-					continue;
-				}
-
-				Transaction transaction = blockTransactions.get(sequence);
-
-				// Transaction needs to be sent to specified recipient
-				List<String> recipientAddresses = transaction.getRecipientAddresses();
-				if (recipientAddresses.contains(atAddress)) {
-					// Found a transaction
-
-					this.setA1(state, new Timestamp(height, timestamp.blockchainId, sequence).longValue());
-
-					// Copy transaction's partial signature into the other three A fields for future verification that it's the same transaction
-					byte[] signature = transaction.getTransactionData().getSignature();
-					this.setA2(state, fromBytes(signature, 8));
-					this.setA3(state, fromBytes(signature, 16));
-					this.setA4(state, fromBytes(signature, 24));
-
-					return;
-				}
-
-				// Transaction wasn't for us - keep going
-				++sequence;
-			}
-
-			// No more transactions - zero A and exit
-			this.zeroA(state);
+			nextTransactionInfo = this.getRepository().getATRepository().findNextTransaction(atAddress, height, sequence);
 		} catch (DataException e) {
 			throw new RuntimeException("AT API unable to fetch next transaction?", e);
 		}
+
+		if (nextTransactionInfo == null) {
+			// No more transactions for AT at this time - zero A and exit
+			this.zeroA(state);
+			return;
+		}
+
+		// Found a transaction
+
+		this.setA1(state, new Timestamp(nextTransactionInfo.height, timestamp.blockchainId, nextTransactionInfo.sequence).longValue());
+
+		// Copy transaction's partial signature into the other three A fields for future verification that it's the same transaction
+		this.setA2(state, BitTwiddling.longFromBEBytes(nextTransactionInfo.signature, 8));
+		this.setA3(state, BitTwiddling.longFromBEBytes(nextTransactionInfo.signature, 16));
+		this.setA4(state, BitTwiddling.longFromBEBytes(nextTransactionInfo.signature, 24));
 	}
 
 	@Override
@@ -282,7 +249,7 @@ public class QortalATAPI extends API {
 
 				byte[] hash = Crypto.digest(input);
 
-				return fromBytes(hash, 0);
+				return BitTwiddling.longFromBEBytes(hash, 0);
 			} catch (DataException e) {
 				throw new RuntimeException("AT API unable to fetch latest block from repository?", e);
 			}
@@ -296,30 +263,14 @@ public class QortalATAPI extends API {
 
 		TransactionData transactionData = this.getTransactionFromA(state);
 
-		byte[] messageData = null;
-
-		switch (transactionData.getType()) {
-			case MESSAGE:
-				messageData = ((MessageTransactionData) transactionData).getData();
-				break;
-
-			case AT:
-				messageData = ((ATTransactionData) transactionData).getMessage();
-				break;
-
-			default:
-				return;
-		}
-
-		// Check data length is appropriate, i.e. not larger than B
-		if (messageData.length > 4 * 8)
-			return;
+		byte[] messageData = this.getMessageFromTransaction(transactionData);
 
 		// Pad messageData to fit B
-		byte[] paddedMessageData = Bytes.ensureCapacity(messageData, 4 * 8, 0);
+		if (messageData.length < 4 * 8)
+			messageData = Bytes.ensureCapacity(messageData, 4 * 8, 0);
 
 		// Endian must be correct here so that (for example) a SHA256 message can be compared to one generated locally
-		this.setB(state, paddedMessageData);
+		this.setB(state, messageData);
 	}
 
 	@Override
@@ -457,12 +408,6 @@ public class QortalATAPI extends API {
 
 	// Utility methods
 
-	/** Convert part of little-endian byte[] to long */
-	/* package */ static long fromBytes(byte[] bytes, int start) {
-		return (bytes[start] & 0xffL) | (bytes[start + 1] & 0xffL) << 8 | (bytes[start + 2] & 0xffL) << 16 | (bytes[start + 3] & 0xffL) << 24
-				| (bytes[start + 4] & 0xffL) << 32 | (bytes[start + 5] & 0xffL) << 40 | (bytes[start + 6] & 0xffL) << 48 | (bytes[start + 7] & 0xffL) << 56;
-	}
-
 	/** Returns partial transaction signature, used to verify we're operating on the same transaction and not naively using block height & sequence. */
 	public static byte[] partialSignature(byte[] fullSignature) {
 		return Arrays.copyOfRange(fullSignature, 8, 32);
@@ -473,7 +418,7 @@ public class QortalATAPI extends API {
 		// Compare end of transaction's signature against A2 thru A4
 		byte[] sig = transactionData.getSignature();
 
-		if (this.getA2(state) != fromBytes(sig, 8) || this.getA3(state) != fromBytes(sig, 16) || this.getA4(state) != fromBytes(sig, 24))
+		if (this.getA2(state) != BitTwiddling.longFromBEBytes(sig, 8) || this.getA3(state) != BitTwiddling.longFromBEBytes(sig, 16) || this.getA4(state) != BitTwiddling.longFromBEBytes(sig, 24))
 			throw new IllegalStateException("Transaction signature in A no longer matches signature from repository");
 	}
 
@@ -497,6 +442,20 @@ public class QortalATAPI extends API {
 		}
 	}
 
+	/** Returns message data from transaction. */
+	/*package*/ byte[] getMessageFromTransaction(TransactionData transactionData) {
+		switch (transactionData.getType()) {
+			case MESSAGE:
+				return ((MessageTransactionData) transactionData).getData();
+
+			case AT:
+				return ((ATTransactionData) transactionData).getMessage();
+
+			default:
+				return null;
+		}
+	}
+
 	/** Returns AT's account */
 	/* package */ Account getATAccount() {
 		return new Account(this.repository, this.atData.getATAddress());
@@ -563,4 +522,8 @@ public class QortalATAPI extends API {
 		super.setB(state, bBytes);
 	}
 
+	protected void zeroB(MachineState state) {
+		super.zeroB(state);
+	}
+
 }

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

@@ -691,6 +691,11 @@ public final class QortalAtLogger extends ExtendedLoggerWrapper implements org.c
         logger.logIfEnabled(FQCN, ERROR, null, msgSupplier, (Throwable) null);
     }
 
+    /** Java 8 version */
+    public void error(final java.util.function.Supplier<String> msgSupplier) {
+        logger.logIfEnabled(FQCN, ERROR, null, () -> msgSupplier.get(), (Throwable) null);
+    }
+
     /**
      * Logs a message (only to be constructed if the logging level is the {@code ERROR}
      * level) including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
@@ -1375,6 +1380,11 @@ public final class QortalAtLogger extends ExtendedLoggerWrapper implements org.c
         logger.logIfEnabled(FQCN, DEBUG, null, msgSupplier, (Throwable) null);
     }
 
+    /** Java 8 version */
+    public void debug(final java.util.function.Supplier<String> msgSupplier) {
+        logger.logIfEnabled(FQCN, DEBUG, null, () -> msgSupplier.get(), (Throwable) null);
+    }
+
     /**
      * Logs a message (only to be constructed if the logging level is the {@code DEBUG}
      * level) including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.
@@ -2059,6 +2069,11 @@ public final class QortalAtLogger extends ExtendedLoggerWrapper implements org.c
         logger.logIfEnabled(FQCN, ECHO, null, msgSupplier, (Throwable) null);
     }
 
+    /** Java 8 version */
+    public void echo(final java.util.function.Supplier<String> msgSupplier) {
+        logger.logIfEnabled(FQCN, ECHO, null, () -> msgSupplier.get(), (Throwable) null);
+    }
+
     /**
      * Logs a message (only to be constructed if the logging level is the {@code ECHO}
      * level) including the stack trace of the {@link Throwable} <code>t</code> passed as parameter.

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

@@ -12,6 +12,7 @@ import org.ciyam.at.IllegalFunctionCodeException;
 import org.ciyam.at.MachineState;
 import org.qortal.crosschain.BTC;
 import org.qortal.crypto.Crypto;
+import org.qortal.data.transaction.TransactionData;
 import org.qortal.settings.Settings;
 
 /**
@@ -22,8 +23,70 @@ import org.qortal.settings.Settings;
  */
 public enum QortalFunctionCode {
 	/**
-	 * <tt>0x0510</tt><br>
-	 * Convert address in B to 20-byte value in LSB of B1, and all of B2 & B3.
+	 * Returns length of message data from transaction in A.<br>
+	 * <tt>0x0501</tt><br>
+	 * If transaction has no 'message', returns -1.
+	 */
+	GET_MESSAGE_LENGTH_FROM_TX_IN_A(0x0501, 0, true) {
+		@Override
+		protected void postCheckExecute(FunctionData functionData, MachineState state, short rawFunctionCode) throws ExecutionException {
+			QortalATAPI api = (QortalATAPI) state.getAPI();
+
+			TransactionData transactionData = api.getTransactionFromA(state);
+
+			byte[] messageData = api.getMessageFromTransaction(transactionData);
+
+			if (messageData == null)
+				functionData.returnValue = -1L;
+			else
+				functionData.returnValue = (long) messageData.length;
+		}
+	},
+	/**
+	 * Put offset 'message' from transaction in A into B<br>
+	 * <tt>0x0502 start-offset</tt><br>
+	 * Copies up to 32 bytes of message data, starting at <tt>start-offset</tt> into B.<br>
+	 * If transaction has no 'message', or <tt>start-offset</tt> out of bounds, then zero B<br>
+	 * Example 'message' could be 256-bit shared secret
+	 */
+	PUT_PARTIAL_MESSAGE_FROM_TX_IN_A_INTO_B(0x0502, 1, false) {
+		@Override
+		protected void postCheckExecute(FunctionData functionData, MachineState state, short rawFunctionCode) throws ExecutionException {
+			QortalATAPI api = (QortalATAPI) state.getAPI();
+
+			// In case something goes wrong, or we don't have enough message data.
+			api.zeroB(state);
+
+			if (functionData.value1 < 0 || functionData.value1 > Integer.MAX_VALUE)
+				return;
+
+			int startOffset = functionData.value1.intValue();
+
+			TransactionData transactionData = api.getTransactionFromA(state);
+
+			byte[] messageData = api.getMessageFromTransaction(transactionData);
+
+			if (messageData == null || startOffset > messageData.length)
+				return;
+
+			/*
+			 * Copy up to 32 bytes of message data into B,
+			 * retain order but pad with zeros in lower bytes.
+			 * 
+			 * So a 4-byte message "a b c d" would copy thusly:
+			 * a b c d 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+			 */
+			int byteCount = Math.min(32, messageData.length - startOffset);
+			byte[] bBytes = new byte[32];
+
+			System.arraycopy(messageData, startOffset, bBytes, 0, byteCount);
+
+			api.setB(state, bBytes);
+		}
+	},
+	/**
+	 * Convert address in B to 20-byte value in LSB of B1, and all of B2 & B3.<br>
+	 * <tt>0x0510</tt>
 	 */
 	CONVERT_B_TO_PKH(0x0510, 0, false) {
 		@Override
@@ -38,8 +101,8 @@ public enum QortalFunctionCode {
 		}
 	},
 	/**
-	 * <tt>0x0511</tt><br>
 	 * Convert 20-byte value in LSB of B1, and all of B2 & B3 to P2SH.<br>
+	 * <tt>0x0511</tt><br>
 	 * P2SH stored in lower 25 bytes of B.
 	 */
 	CONVERT_B_TO_P2SH(0x0511, 0, false) {
@@ -51,8 +114,8 @@ public enum QortalFunctionCode {
 		}
 	},
 	/**
-	 * <tt>0x0512</tt><br>
 	 * Convert 20-byte value in LSB of B1, and all of B2 & B3 to Qortal address.<br>
+	 * <tt>0x0512</tt><br>
 	 * Qortal address stored in lower 25 bytes of B.
 	 */
 	CONVERT_B_TO_QORTAL(0x0512, 0, false) {

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

@@ -215,6 +215,9 @@ public class Block {
 	/** Always use getExpandedAccounts() to access this, as it's lazy-instantiated. */
 	private List<ExpandedAccount> cachedExpandedAccounts = null;
 
+	/** Opportunistic cache of this block's valid online accounts. Only created by call to isValid(). */
+	private List<OnlineAccountData> cachedValidOnlineAccounts = null;
+
 	// Other useful constants
 
 	private static final BigInteger MAX_DISTANCE;
@@ -940,24 +943,46 @@ public class Block {
 			return ValidationResult.ONLINE_ACCOUNT_SIGNATURES_MALFORMED;
 
 		// Check signatures
-		List<byte[]> onlineAccountsSignatures = BlockTransformer.decodeTimestampSignatures(this.blockData.getOnlineAccountsSignatures());
 		long onlineTimestamp = this.blockData.getOnlineAccountsTimestamp();
 		byte[] onlineTimestampBytes = Longs.toByteArray(onlineTimestamp);
-		List<OnlineAccountData> onlineAccounts = Controller.getInstance().getOnlineAccounts();
+
+		// If this block is much older than current online timestamp, then there's no point checking current online accounts
+		List<OnlineAccountData> currentOnlineAccounts = onlineTimestamp < NTP.getTime() - Controller.ONLINE_TIMESTAMP_MODULUS
+				? null
+				: Controller.getInstance().getOnlineAccounts();
+		List<OnlineAccountData> latestBlocksOnlineAccounts = Controller.getInstance().getLatestBlocksOnlineAccounts();
+
+		// Extract online accounts' timestamp signatures from block data
+		List<byte[]> onlineAccountsSignatures = BlockTransformer.decodeTimestampSignatures(this.blockData.getOnlineAccountsSignatures());
+
+		// We'll build up a list of online accounts to hand over to Controller if block is added to chain
+		// and this will become latestBlocksOnlineAccounts (above) to reduce CPU load when we process next block...
+		List<OnlineAccountData> ourOnlineAccounts = new ArrayList<>();
 
 		for (int i = 0; i < onlineAccountsSignatures.size(); ++i) {
 			byte[] signature = onlineAccountsSignatures.get(i);
 			byte[] publicKey = expandedAccounts.get(i).getRewardSharePublicKey();
 
-			// If signature is still current then no need to perform Ed25519 verify
 			OnlineAccountData onlineAccountData = new OnlineAccountData(onlineTimestamp, signature, publicKey);
-			if (onlineAccounts.remove(onlineAccountData)) // remove() is like contains() but also reduces the number to check next time
+			ourOnlineAccounts.add(onlineAccountData);
+
+			// If signature is still current then no need to perform Ed25519 verify
+			if (currentOnlineAccounts != null && currentOnlineAccounts.remove(onlineAccountData))
+				// remove() returned true, so online account still current
+				// and one less entry in currentOnlineAccounts to check next time
+				continue;
+
+			// If signature was okay in latest block then no need to perform Ed25519 verify
+			if (latestBlocksOnlineAccounts != null && latestBlocksOnlineAccounts.contains(onlineAccountData))
 				continue;
 
 			if (!Crypto.verify(publicKey, signature, onlineTimestampBytes))
 				return ValidationResult.ONLINE_ACCOUNT_SIGNATURE_INCORRECT;
 		}
 
+		// All online accounts valid, so save our list of online accounts for potential later use
+		this.cachedValidOnlineAccounts = ourOnlineAccounts;
+
 		return ValidationResult.OK;
 	}
 
@@ -1271,6 +1296,9 @@ public class Block {
 		linkTransactionsToBlock();
 
 		postBlockTidy();
+
+		// Give Controller our cached, valid online accounts data (if any) to help reduce CPU load for next block
+		Controller.getInstance().pushLatestBlocksOnlineAccounts(this.cachedValidOnlineAccounts);
 	}
 
 	protected void increaseAccountLevels() throws DataException {
@@ -1474,6 +1502,9 @@ public class Block {
 		this.blockData.setHeight(null);
 
 		postBlockTidy();
+
+		// Remove any cached, valid online accounts data from Controller
+		Controller.getInstance().popLatestBlocksOnlineAccounts();
 	}
 
 	protected void orphanTransactionsFromBlock() throws DataException {

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

@@ -482,7 +482,7 @@ public class BlockChain {
 	}
 
 	/**
-	 * Some sort start-up/initialization/checking method.
+	 * Some sort of start-up/initialization/checking method.
 	 * 
 	 * @throws SQLException
 	 */
@@ -492,7 +492,9 @@ public class BlockChain {
 			rebuildBlockchain();
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			BlockData detachedBlockData = repository.getBlockRepository().getDetachedBlockSignature();
+			int startHeight = Math.max(repository.getBlockRepository().getBlockchainHeight() - 1440, 1);
+
+			BlockData detachedBlockData = repository.getBlockRepository().getDetachedBlockSignature(startHeight);
 
 			if (detachedBlockData != null) {
 				LOGGER.error(String.format("Block %d's reference does not match any block's signature", detachedBlockData.getHeight()));

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

@@ -214,8 +214,9 @@ public class AutoUpdate extends Thread {
 			return false; // failed - try another repo
 		}
 
-		// Give repository a chance to backup in case things go badly wrong
-		RepositoryManager.backup(true);
+		// Give repository a chance to backup in case things go badly wrong (if enabled)
+		if (Settings.getInstance().getRepositoryBackupInterval() > 0)
+			RepositoryManager.backup(true);
 
 		// Call ApplyUpdate to end this process (unlocking current JAR so it can be replaced)
 		String javaHome = System.getProperty("java.home");

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

@@ -1,9 +1,12 @@
 package org.qortal.controller;
 
+import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
 
 import org.eclipse.jetty.websocket.api.Session;
+import org.qortal.api.model.BlockInfo;
 import org.qortal.data.block.BlockData;
 
 public class BlockNotifier {
@@ -12,7 +15,7 @@ public class BlockNotifier {
 
 	@FunctionalInterface
 	public interface Listener {
-		void notify(BlockData blockData);
+		void notify(BlockInfo blockInfo);
 	}
 
 	private Map<Session, Listener> listenersBySession = new HashMap<>();
@@ -27,17 +30,32 @@ public class BlockNotifier {
 		return instance;
 	}
 
-	public synchronized void register(Session session, Listener listener) {
-		this.listenersBySession.put(session, listener);
+	public void register(Session session, Listener listener) {
+		synchronized (this.listenersBySession) {
+			this.listenersBySession.put(session, listener);
+		}
 	}
 
-	public synchronized void deregister(Session session) {
-		this.listenersBySession.remove(session);
+	public void deregister(Session session) {
+		synchronized (this.listenersBySession) {
+			this.listenersBySession.remove(session);
+		}
 	}
 
-	public synchronized void onNewBlock(BlockData blockData) {
-		for (Listener listener : this.listenersBySession.values())
-			listener.notify(blockData);
+	public void onNewBlock(BlockData blockData) {
+		// Convert BlockData to BlockInfo
+		BlockInfo blockInfo = new BlockInfo(blockData);
+
+		for (Listener listener : getAllListeners())
+			listener.notify(blockInfo);
+	}
+
+	private Collection<Listener> getAllListeners() {
+		// Make a copy of listeners to both avoid concurrent modification
+		// and reduce synchronization time
+		synchronized (this.listenersBySession) {
+			return new ArrayList<>(this.listenersBySession.values());
+		}
 	}
 
 }

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

@@ -1,5 +1,7 @@
 package org.qortal.controller;
 
+import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -27,22 +29,34 @@ public class ChatNotifier {
 		return instance;
 	}
 
-	public synchronized void register(Session session, Listener listener) {
-		this.listenersBySession.put(session, listener);
+	public void register(Session session, Listener listener) {
+		synchronized (this.listenersBySession) {
+			this.listenersBySession.put(session, listener);
+		}
 	}
 
-	public synchronized void deregister(Session session) {
-		this.listenersBySession.remove(session);
+	public void deregister(Session session) {
+		synchronized (this.listenersBySession) {
+			this.listenersBySession.remove(session);
+		}
 	}
 
-	public synchronized void onNewChatTransaction(ChatTransactionData chatTransactionData) {
-		for (Listener listener : this.listenersBySession.values())
+	public void onNewChatTransaction(ChatTransactionData chatTransactionData) {
+		for (Listener listener : getAllListeners())
 			listener.notify(chatTransactionData);
 	}
 
-	public synchronized void onGroupMembershipChange() {
-		for (Listener listener : this.listenersBySession.values())
+	public void onGroupMembershipChange() {
+		for (Listener listener : getAllListeners())
 			listener.notify(null);
 	}
 
+	private Collection<Listener> getAllListeners() {
+		// Make a copy of listeners to both avoid concurrent modification
+		// and reduce synchronization time
+		synchronized (this.listenersBySession) {
+			return new ArrayList<>(this.listenersBySession.values());
+		}
+	}
+
 }

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

@@ -9,9 +9,11 @@ import java.security.Security;
 import java.time.LocalDateTime;
 import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
+import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.Deque;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
@@ -112,8 +114,10 @@ public class Controller extends Thread {
 	// To do with online accounts list
 	private static final long ONLINE_ACCOUNTS_TASKS_INTERVAL = 10 * 1000L; // ms
 	private static final long ONLINE_ACCOUNTS_BROADCAST_INTERVAL = 1 * 60 * 1000L; // ms
-	private static final long ONLINE_TIMESTAMP_MODULUS = 5 * 60 * 1000L;
+	public static final long ONLINE_TIMESTAMP_MODULUS = 5 * 60 * 1000L;
 	private static final long LAST_SEEN_EXPIRY_PERIOD = (ONLINE_TIMESTAMP_MODULUS * 2) + (1 * 60 * 1000L);
+	/** How many (latest) blocks' worth of online accounts we cache */
+	private static final int MAX_BLOCKS_CACHED_ONLINE_ACCOUNTS = 2;
 
 	private static volatile boolean isStopping = false;
 	private static BlockMinter blockMinter = null;
@@ -168,8 +172,10 @@ public class Controller extends Thread {
 	/** Lock for only allowing one blockchain-modifying codepath at a time. e.g. synchronization or newly minted block. */
 	private final ReentrantLock blockchainLock = new ReentrantLock();
 
-	/** Cache of 'online accounts' */
+	/** Cache of current 'online accounts' */
 	List<OnlineAccountData> onlineAccounts = new ArrayList<>();
+	/** Cache of latest blocks' online accounts */
+	Deque<List<OnlineAccountData>> latestBlocksOnlineAccounts = new ArrayDeque<>(MAX_BLOCKS_CACHED_ONLINE_ACCOUNTS);
 
 	// Constructors
 
@@ -537,8 +543,11 @@ public class Controller extends Thread {
 
 	public SynchronizationResult actuallySynchronize(Peer peer, boolean force) throws InterruptedException {
 		syncPercent = (this.chainTip.getHeight() * 100) / peer.getChainTipData().getLastHeight();
-		isSynchronizing = true;
-		updateSysTray();
+		// Only update SysTray if we're potentially changing height
+		if (syncPercent < 100) {
+			isSynchronizing = true;
+			updateSysTray();
+		}
 
 		BlockData priorChainTip = this.chainTip;
 
@@ -584,7 +593,6 @@ public class Controller extends Thread {
 					break;
 
 				case OK:
-					requestSysTrayUpdate = true;
 					// fall-through...
 				case NOTHING_TO_DO: {
 					// Update our list of inferior chain tips
@@ -611,14 +619,13 @@ public class Controller extends Thread {
 				// Reset our cache of inferior chains
 				inferiorChainSignatures.clear();
 
-				// Update chain-tip, notify peers, websockets, etc.
+				// Update chain-tip, systray, notify peers, websockets, etc.
 				this.onNewBlock(newChainTip);
 			}
 
 			return syncResult;
 		} finally {
 			isSynchronizing = false;
-			requestSysTrayUpdate = true;
 		}
 	}
 
@@ -765,8 +772,10 @@ public class Controller extends Thread {
 		BlockData latestBlockData = getChainTip();
 		network.broadcast(peer -> network.buildHeightMessage(peer, latestBlockData));
 
-		// Send (if outbound) / Request unconfirmed transaction signatures
-		network.broadcast(network::buildGetUnconfirmedTransactionsMessage);
+		// Request unconfirmed transaction signatures, but only if we're up-to-date.
+		// If we're NOT up-to-date then priority is synchronizing first
+		if (isUpToDate())
+			network.broadcast(network::buildGetUnconfirmedTransactionsMessage);
 	}
 
 	public void onMintingPossibleChange(boolean isMintingPossible) {
@@ -789,6 +798,9 @@ public class Controller extends Thread {
 				this.notifyGroupMembershipChange = false;
 				ChatNotifier.getInstance().onGroupMembershipChange();
 			}
+
+			// Trade-bot might want to perform some actions too
+			TradeBot.getInstance().onChainTipChange();
 		});
 	}
 
@@ -888,8 +900,16 @@ public class Controller extends Thread {
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			BlockData blockData = repository.getBlockRepository().fromSignature(signature);
 			if (blockData == null) {
-				LOGGER.debug(() -> String.format("Ignoring GET_BLOCK request from peer %s for unknown block %s", peer, Base58.encode(signature)));
-				// Send no response at all???
+				// We don't have this block
+
+				// Send valid, yet unexpected message type in response, so peer's synchronizer doesn't have to wait for timeout
+				LOGGER.debug(() -> String.format("Sending 'block unknown' response to peer %s for GET_BLOCK request for unknown block %s", peer, Base58.encode(signature)));
+
+				// We'll send empty block summaries message as it's very short
+				Message blockUnknownMessage = new BlockSummariesMessage(Collections.emptyList());
+				blockUnknownMessage.setId(message.getId());
+				if (!peer.sendMessage(blockUnknownMessage))
+					peer.disconnect("failed to send block-unknown response");
 				return;
 			}
 
@@ -1040,7 +1060,12 @@ public class Controller extends Thread {
 
 	private void onNetworkGetUnconfirmedTransactionsMessage(Peer peer, Message message) {
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			List<byte[]> signatures = repository.getTransactionRepository().getUnconfirmedTransactionSignatures();
+			List<byte[]> signatures = Collections.emptyList();
+
+			// If we're NOT up-to-date then don't send out unconfirmed transactions
+			// as it's possible they are already included in a later block that we don't have.
+			if (isUpToDate())
+				signatures = repository.getTransactionRepository().getUnconfirmedTransactionSignatures();
 
 			Message transactionSignaturesMessage = new TransactionSignaturesMessage(signatures);
 			if (!peer.sendMessage(transactionSignaturesMessage))
@@ -1446,6 +1471,32 @@ public class Controller extends Thread {
 		}
 	}
 
+	/** Returns cached, unmodifiable list of latest block's online accounts. */
+	public List<OnlineAccountData> getLatestBlocksOnlineAccounts() {
+		synchronized (this.latestBlocksOnlineAccounts) {
+			return this.latestBlocksOnlineAccounts.peekFirst();
+		}
+	}
+
+	/** Caches list of latest block's online accounts. Typically called by Block.process() */
+	public void pushLatestBlocksOnlineAccounts(List<OnlineAccountData> latestBlocksOnlineAccounts) {
+		synchronized (this.latestBlocksOnlineAccounts) {
+			if (this.latestBlocksOnlineAccounts.size() == MAX_BLOCKS_CACHED_ONLINE_ACCOUNTS)
+				this.latestBlocksOnlineAccounts.pollLast();
+
+			this.latestBlocksOnlineAccounts.addFirst(latestBlocksOnlineAccounts == null
+					? Collections.emptyList()
+					: Collections.unmodifiableList(latestBlocksOnlineAccounts));
+		}
+	}
+
+	/** Reverts list of latest block's online accounts. Typically called by Block.orphan() */
+	public void popLatestBlocksOnlineAccounts() {
+		synchronized (this.latestBlocksOnlineAccounts) {
+			this.latestBlocksOnlineAccounts.pollFirst();
+		}
+	}
+
 	public byte[] fetchArbitraryData(byte[] signature) throws InterruptedException {
 		// Build request
 		Message getArbitraryDataMessage = new GetArbitraryDataMessage(signature);

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

@@ -1,5 +1,7 @@
 package org.qortal.controller;
 
+import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -26,17 +28,29 @@ public class StatusNotifier {
 		return instance;
 	}
 
-	public synchronized void register(Session session, Listener listener) {
-		this.listenersBySession.put(session, listener);
+	public void register(Session session, Listener listener) {
+		synchronized (this.listenersBySession) {
+			this.listenersBySession.put(session, listener);
+		}
 	}
 
-	public synchronized void deregister(Session session) {
-		this.listenersBySession.remove(session);
+	public void deregister(Session session) {
+		synchronized (this.listenersBySession) {
+			this.listenersBySession.remove(session);
+		}
 	}
 
-	public synchronized void onStatusChange(long now) {
-		for (Listener listener : this.listenersBySession.values())
+	public void onStatusChange(long now) {
+		for (Listener listener : getAllListeners())
 			listener.notify(now);
 	}
 
+	private Collection<Listener> getAllListeners() {
+		// Make a copy of listeners to both avoid concurrent modification
+		// and reduce synchronization time
+		synchronized (this.listenersBySession) {
+			return new ArrayList<>(this.listenersBySession.values());
+		}
+	}
+
 }

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

@@ -126,167 +126,22 @@ public class Synchronizer {
 
 					// Unless we're doing a forced sync, we might need to compare blocks after common block
 					if (!force && ourInitialHeight > commonBlockHeight) {
-						// If our latest block is very old, we're very behind and should ditch our fork.
-						final Long minLatestBlockTimestamp = Controller.getMinimumLatestBlockTimestamp();
-						if (minLatestBlockTimestamp == null)
-							return SynchronizationResult.REPOSITORY_ISSUE;
-
-						if (ourLatestBlockData.getTimestamp() < minLatestBlockTimestamp) {
-							LOGGER.info(String.format("Ditching our chain after height %d as our latest block is very old", commonBlockHeight));
-						} else {
-							// Compare chain weights
-
-							LOGGER.debug(String.format("Comparing chains from block %d with peer %s", commonBlockHeight + 1, peer));
-
-							// Fetch remaining peer's block summaries (which we also use to fill signatures list)
-							int peerBlockCount = peerHeight - commonBlockHeight;
-
-							while (peerBlockSummaries.size() < peerBlockCount) {
-								if (Controller.isStopping())
-									return SynchronizationResult.SHUTTING_DOWN;
-
-								int lastSummaryHeight = commonBlockHeight + peerBlockSummaries.size();
-								byte[] previousSignature;
-								if (peerBlockSummaries.isEmpty())
-									previousSignature = commonBlockSig;
-								else
-									previousSignature = peerBlockSummaries.get(peerBlockSummaries.size() - 1).getSignature();
-
-								List<BlockSummaryData> moreBlockSummaries = this.getBlockSummaries(peer, previousSignature, peerBlockCount - peerBlockSummaries.size());
-
-								if (moreBlockSummaries == null || moreBlockSummaries.isEmpty()) {
-									LOGGER.info(String.format("Peer %s failed to respond with block summaries after height %d, sig %.8s", peer,
-											lastSummaryHeight, Base58.encode(previousSignature)));
-									return SynchronizationResult.NO_REPLY;
-								}
-
-								// Check peer sent valid heights
-								for (int i = 0; i < moreBlockSummaries.size(); ++i) {
-									++lastSummaryHeight;
-
-									BlockSummaryData blockSummary = moreBlockSummaries.get(i);
-
-									if (blockSummary.getHeight() != lastSummaryHeight) {
-										LOGGER.info(String.format("Peer %s responded with invalid block summary for height %d, sig %.8s", peer,
-												lastSummaryHeight, Base58.encode(blockSummary.getSignature())));
-										return SynchronizationResult.NO_REPLY;
-									}
-								}
-
-								peerBlockSummaries.addAll(moreBlockSummaries);
-							}
-
-							// Fetch our corresponding block summaries
-							List<BlockSummaryData> ourBlockSummaries = repository.getBlockRepository().getBlockSummaries(commonBlockHeight + 1, ourInitialHeight);
-
-							// Populate minter account levels for both lists of block summaries
-							populateBlockSummariesMinterLevels(repository, peerBlockSummaries);
-							populateBlockSummariesMinterLevels(repository, ourBlockSummaries);
-
-							// Calculate cumulative chain weights of both blockchain subsets, from common block to highest mutual block.
-							BigInteger ourChainWeight = Block.calcChainWeight(commonBlockHeight, commonBlockSig, ourBlockSummaries);
-							BigInteger peerChainWeight = Block.calcChainWeight(commonBlockHeight, commonBlockSig, peerBlockSummaries);
-
-							// If our blockchain has greater weight then don't synchronize with peer
-							if (ourChainWeight.compareTo(peerChainWeight) >= 0) {
-								LOGGER.debug(String.format("Not synchronizing with peer %s as we have better blockchain", peer));
-								NumberFormat formatter = new DecimalFormat("0.###E0");
-								LOGGER.debug(String.format("Our chain weight: %s, peer's chain weight: %s (higher is better)", formatter.format(ourChainWeight), formatter.format(peerChainWeight)));
-								return SynchronizationResult.INFERIOR_CHAIN;
-							}
-						}
+						SynchronizationResult chainCompareResult = compareChains(repository, commonBlockData, ourLatestBlockData, peer, peerHeight, peerBlockSummaries);
+						if (chainCompareResult != SynchronizationResult.OK)
+							return chainCompareResult;
 					}
 
-					int ourHeight = ourInitialHeight;
-					if (ourHeight > commonBlockHeight) {
-						// Unwind to common block (unless common block is our latest block)
-						LOGGER.debug(String.format("Orphaning blocks back to common block height %d, sig %.8s", commonBlockHeight, commonBlockSig58));
-
-						while (ourHeight > commonBlockHeight) {
-							if (Controller.isStopping())
-								return SynchronizationResult.SHUTTING_DOWN;
-
-							BlockData blockData = repository.getBlockRepository().fromHeight(ourHeight);
-							Block block = new Block(repository, blockData);
-							block.orphan();
-
-							--ourHeight;
-						}
-
-						LOGGER.debug(String.format("Orphaned blocks back to height %d, sig %.8s - fetching blocks from peer %s", commonBlockHeight, commonBlockSig58, peer));
+					SynchronizationResult syncResult = null;
+					if (commonBlockHeight < ourInitialHeight) {
+						// Peer's chain is better, sync to that one
+						syncResult = syncToPeerChain(repository, commonBlockData, ourInitialHeight, peer, peerHeight, peerBlockSummaries);
 					} else {
-						LOGGER.debug(String.format("Fetching new blocks from peer %s", peer));
+						// Simply fetch and apply blocks as they arrive
+						syncResult = applyNewBlocks(repository, commonBlockData, ourInitialHeight, peer, peerHeight, peerBlockSummaries);
 					}
 
-					// Fetch, and apply, blocks from peer
-					byte[] latestPeerSignature = commonBlockSig;
-					int maxBatchHeight = commonBlockHeight + SYNC_BATCH_SIZE;
-
-					// Convert any block summaries from above into signatures to request from peer
-					List<byte[]> peerBlockSignatures = peerBlockSummaries.stream().map(BlockSummaryData::getSignature).collect(Collectors.toList());
-
-					while (ourHeight < peerHeight && ourHeight < maxBatchHeight) {
-						if (Controller.isStopping())
-							return SynchronizationResult.SHUTTING_DOWN;
-
-						// Do we need more signatures?
-						if (peerBlockSignatures.isEmpty()) {
-							int numberRequested = maxBatchHeight - ourHeight;
-							LOGGER.trace(String.format("Requesting %d signature%s after height %d, sig %.8s",
-									numberRequested, (numberRequested != 1 ? "s": ""), ourHeight, Base58.encode(latestPeerSignature)));
-
-							peerBlockSignatures = this.getBlockSignatures(peer, latestPeerSignature, numberRequested);
-
-							if (peerBlockSignatures == null || peerBlockSignatures.isEmpty()) {
-								LOGGER.info(String.format("Peer %s failed to respond with more block signatures after height %d, sig %.8s", peer,
-										ourHeight, Base58.encode(latestPeerSignature)));
-								return SynchronizationResult.NO_REPLY;
-							}
-
-							LOGGER.trace(String.format("Received %s signature%s", peerBlockSignatures.size(), (peerBlockSignatures.size() != 1 ? "s" : "")));
-						}
-
-						latestPeerSignature = peerBlockSignatures.get(0);
-						peerBlockSignatures.remove(0);
-						++ourHeight;
-
-						Block newBlock = this.fetchBlock(repository, peer, latestPeerSignature);
-
-						if (newBlock == null) {
-							LOGGER.info(String.format("Peer %s failed to respond with block for height %d, sig %.8s", peer,
-									ourHeight, Base58.encode(latestPeerSignature)));
-							return SynchronizationResult.NO_REPLY;
-						}
-
-						if (!newBlock.isSignatureValid()) {
-							LOGGER.info(String.format("Peer %s sent block with invalid signature for height %d, sig %.8s", peer,
-									ourHeight, Base58.encode(latestPeerSignature)));
-							return SynchronizationResult.INVALID_DATA;
-						}
-
-						// Transactions are transmitted without approval status so determine that now
-						for (Transaction transaction : newBlock.getTransactions())
-							transaction.setInitialApprovalStatus();
-
-						ValidationResult blockResult = newBlock.isValid();
-						if (blockResult != ValidationResult.OK) {
-							LOGGER.info(String.format("Peer %s sent invalid block for height %d, sig %.8s: %s", peer,
-									ourHeight, Base58.encode(latestPeerSignature), blockResult.name()));
-							return SynchronizationResult.INVALID_DATA;
-						}
-
-						// Save transactions attached to this block
-						for (Transaction transaction : newBlock.getTransactions()) {
-							TransactionData transactionData = transaction.getTransactionData();
-							repository.getTransactionRepository().save(transactionData);
-						}
-
-						newBlock.process();
-
-						// If we've grown our blockchain then at least save progress so far
-						if (ourHeight > ourInitialHeight)
-							repository.saveChanges();
-					}
+					if (syncResult != SynchronizationResult.OK)
+						return syncResult;
 
 					// Commit
 					repository.saveChanges();
@@ -396,6 +251,268 @@ public class Synchronizer {
 		return SynchronizationResult.OK;
 	}
 
+	private SynchronizationResult compareChains(Repository repository, BlockData commonBlockData, BlockData ourLatestBlockData,
+			Peer peer, int peerHeight, List<BlockSummaryData> peerBlockSummaries) throws DataException, InterruptedException {
+		final int commonBlockHeight = commonBlockData.getHeight();
+		final byte[] commonBlockSig = commonBlockData.getSignature();
+
+		// If our latest block is very old, we're very behind and should ditch our fork.
+		final Long minLatestBlockTimestamp = Controller.getMinimumLatestBlockTimestamp();
+		if (minLatestBlockTimestamp == null)
+			return SynchronizationResult.REPOSITORY_ISSUE;
+
+		if (ourLatestBlockData.getTimestamp() < minLatestBlockTimestamp) {
+			LOGGER.info(String.format("Ditching our chain after height %d as our latest block is very old", commonBlockHeight));
+		} else {
+			// Compare chain weights
+
+			LOGGER.debug(String.format("Comparing chains from block %d with peer %s", commonBlockHeight + 1, peer));
+
+			// Fetch remaining peer's block summaries (which we also use to fill signatures list)
+			int peerBlockCount = peerHeight - commonBlockHeight;
+
+			while (peerBlockSummaries.size() < peerBlockCount) {
+				if (Controller.isStopping())
+					return SynchronizationResult.SHUTTING_DOWN;
+
+				int lastSummaryHeight = commonBlockHeight + peerBlockSummaries.size();
+				byte[] previousSignature;
+				if (peerBlockSummaries.isEmpty())
+					previousSignature = commonBlockSig;
+				else
+					previousSignature = peerBlockSummaries.get(peerBlockSummaries.size() - 1).getSignature();
+
+				List<BlockSummaryData> moreBlockSummaries = this.getBlockSummaries(peer, previousSignature, peerBlockCount - peerBlockSummaries.size());
+
+				if (moreBlockSummaries == null || moreBlockSummaries.isEmpty()) {
+					LOGGER.info(String.format("Peer %s failed to respond with block summaries after height %d, sig %.8s", peer,
+							lastSummaryHeight, Base58.encode(previousSignature)));
+					return SynchronizationResult.NO_REPLY;
+				}
+
+				// Check peer sent valid heights
+				for (int i = 0; i < moreBlockSummaries.size(); ++i) {
+					++lastSummaryHeight;
+
+					BlockSummaryData blockSummary = moreBlockSummaries.get(i);
+
+					if (blockSummary.getHeight() != lastSummaryHeight) {
+						LOGGER.info(String.format("Peer %s responded with invalid block summary for height %d, sig %.8s", peer,
+								lastSummaryHeight, Base58.encode(blockSummary.getSignature())));
+						return SynchronizationResult.NO_REPLY;
+					}
+				}
+
+				peerBlockSummaries.addAll(moreBlockSummaries);
+			}
+
+			// Fetch our corresponding block summaries
+			List<BlockSummaryData> ourBlockSummaries = repository.getBlockRepository().getBlockSummaries(commonBlockHeight + 1, ourLatestBlockData.getHeight());
+
+			// Populate minter account levels for both lists of block summaries
+			populateBlockSummariesMinterLevels(repository, peerBlockSummaries);
+			populateBlockSummariesMinterLevels(repository, ourBlockSummaries);
+
+			// Calculate cumulative chain weights of both blockchain subsets, from common block to highest mutual block.
+			BigInteger ourChainWeight = Block.calcChainWeight(commonBlockHeight, commonBlockSig, ourBlockSummaries);
+			BigInteger peerChainWeight = Block.calcChainWeight(commonBlockHeight, commonBlockSig, peerBlockSummaries);
+
+			// If our blockchain has greater weight then don't synchronize with peer
+			if (ourChainWeight.compareTo(peerChainWeight) >= 0) {
+				LOGGER.debug(String.format("Not synchronizing with peer %s as we have better blockchain", peer));
+				NumberFormat formatter = new DecimalFormat("0.###E0");
+				LOGGER.debug(String.format("Our chain weight: %s, peer's chain weight: %s (higher is better)", formatter.format(ourChainWeight), formatter.format(peerChainWeight)));
+				return SynchronizationResult.INFERIOR_CHAIN;
+			}
+		}
+
+		return SynchronizationResult.OK;
+	}
+
+	private SynchronizationResult syncToPeerChain(Repository repository, BlockData commonBlockData, int ourInitialHeight,
+			Peer peer, final int peerHeight, List<BlockSummaryData> peerBlockSummaries) throws DataException, InterruptedException {
+		final int commonBlockHeight = commonBlockData.getHeight();
+		final byte[] commonBlockSig = commonBlockData.getSignature();
+		String commonBlockSig58 = Base58.encode(commonBlockSig);
+
+		LOGGER.debug(() -> String.format("Fetching peer %s chain from height %d, sig %.8s", peer, commonBlockHeight, commonBlockSig58));
+
+		int ourHeight = ourInitialHeight;
+
+		// Overall plan: fetch peer's blocks first, then orphan, then apply
+
+		// Convert any leftover (post-common) block summaries into signatures to request from peer
+		List<byte[]> peerBlockSignatures = peerBlockSummaries.stream().map(BlockSummaryData::getSignature).collect(Collectors.toList());
+
+		// Fetch remaining block signatures, if needed
+		int numberSignaturesRequired = peerBlockSignatures.size() - (peerHeight - commonBlockHeight);
+		if (numberSignaturesRequired > 0) {
+			byte[] latestPeerSignature = peerBlockSignatures.isEmpty() ? commonBlockSig : peerBlockSignatures.get(peerBlockSignatures.size() - 1);
+
+			LOGGER.trace(String.format("Requesting %d signature%s after height %d, sig %.8s",
+					numberSignaturesRequired, (numberSignaturesRequired != 1 ? "s": ""), ourHeight, Base58.encode(latestPeerSignature)));
+
+			List<byte[]> moreBlockSignatures = this.getBlockSignatures(peer, latestPeerSignature, numberSignaturesRequired);
+
+			if (moreBlockSignatures == null || moreBlockSignatures.isEmpty()) {
+				LOGGER.info(String.format("Peer %s failed to respond with more block signatures after height %d, sig %.8s", peer,
+						ourHeight, Base58.encode(latestPeerSignature)));
+				return SynchronizationResult.NO_REPLY;
+			}
+
+			LOGGER.trace(String.format("Received %s signature%s", peerBlockSignatures.size(), (peerBlockSignatures.size() != 1 ? "s" : "")));
+
+			peerBlockSignatures.addAll(moreBlockSignatures);
+		}
+
+		// Fetch blocks using signatures
+		LOGGER.debug(String.format("Fetching new blocks from peer %s", peer));
+		List<Block> peerBlocks = new ArrayList<>();
+
+		for (byte[] blockSignature : peerBlockSignatures) {
+			Block newBlock = this.fetchBlock(repository, peer, blockSignature);
+
+			if (newBlock == null) {
+				LOGGER.info(String.format("Peer %s failed to respond with block for height %d, sig %.8s", peer,
+						ourHeight, Base58.encode(blockSignature)));
+				return SynchronizationResult.NO_REPLY;
+			}
+
+			if (!newBlock.isSignatureValid()) {
+				LOGGER.info(String.format("Peer %s sent block with invalid signature for height %d, sig %.8s", peer,
+						ourHeight, Base58.encode(blockSignature)));
+				return SynchronizationResult.INVALID_DATA;
+			}
+
+			// Transactions are transmitted without approval status so determine that now
+			for (Transaction transaction : newBlock.getTransactions())
+				transaction.setInitialApprovalStatus();
+
+			peerBlocks.add(newBlock);
+		}
+
+		// Unwind to common block (unless common block is our latest block)
+		LOGGER.debug(String.format("Orphaning blocks back to common block height %d, sig %.8s", commonBlockHeight, commonBlockSig58));
+
+		while (ourHeight > commonBlockHeight) {
+			if (Controller.isStopping())
+				return SynchronizationResult.SHUTTING_DOWN;
+
+			BlockData blockData = repository.getBlockRepository().fromHeight(ourHeight);
+			Block block = new Block(repository, blockData);
+			block.orphan();
+
+			--ourHeight;
+		}
+
+		LOGGER.debug(String.format("Orphaned blocks back to height %d, sig %.8s - applying new blocks from peer %s", commonBlockHeight, commonBlockSig58, peer));
+
+		for (Block newBlock : peerBlocks) {
+			ValidationResult blockResult = newBlock.isValid();
+			if (blockResult != ValidationResult.OK) {
+				LOGGER.info(String.format("Peer %s sent invalid block for height %d, sig %.8s: %s", peer,
+						ourHeight, Base58.encode(newBlock.getSignature()), blockResult.name()));
+				return SynchronizationResult.INVALID_DATA;
+			}
+
+			// Save transactions attached to this block
+			for (Transaction transaction : newBlock.getTransactions()) {
+				TransactionData transactionData = transaction.getTransactionData();
+				repository.getTransactionRepository().save(transactionData);
+			}
+
+			newBlock.process();
+
+			// If we've grown our blockchain then at least save progress so far
+			if (ourHeight > ourInitialHeight)
+				repository.saveChanges();
+		}
+
+		return SynchronizationResult.OK;
+	}
+
+	private SynchronizationResult applyNewBlocks(Repository repository, BlockData commonBlockData, int ourInitialHeight,
+			Peer peer, int peerHeight, List<BlockSummaryData> peerBlockSummaries) throws InterruptedException, DataException {
+		LOGGER.debug(String.format("Fetching new blocks from peer %s", peer));
+
+		final int commonBlockHeight = commonBlockData.getHeight();
+		final byte[] commonBlockSig = commonBlockData.getSignature();
+
+		int ourHeight = ourInitialHeight;
+
+		// Fetch, and apply, blocks from peer
+		byte[] latestPeerSignature = commonBlockSig;
+		int maxBatchHeight = commonBlockHeight + SYNC_BATCH_SIZE;
+
+		// Convert any block summaries from above into signatures to request from peer
+		List<byte[]> peerBlockSignatures = peerBlockSummaries.stream().map(BlockSummaryData::getSignature).collect(Collectors.toList());
+
+		while (ourHeight < peerHeight && ourHeight < maxBatchHeight) {
+			if (Controller.isStopping())
+				return SynchronizationResult.SHUTTING_DOWN;
+
+			// Do we need more signatures?
+			if (peerBlockSignatures.isEmpty()) {
+				int numberRequested = maxBatchHeight - ourHeight;
+				LOGGER.trace(String.format("Requesting %d signature%s after height %d, sig %.8s",
+						numberRequested, (numberRequested != 1 ? "s": ""), ourHeight, Base58.encode(latestPeerSignature)));
+
+				peerBlockSignatures = this.getBlockSignatures(peer, latestPeerSignature, numberRequested);
+
+				if (peerBlockSignatures == null || peerBlockSignatures.isEmpty()) {
+					LOGGER.info(String.format("Peer %s failed to respond with more block signatures after height %d, sig %.8s", peer,
+							ourHeight, Base58.encode(latestPeerSignature)));
+					return SynchronizationResult.NO_REPLY;
+				}
+
+				LOGGER.trace(String.format("Received %s signature%s", peerBlockSignatures.size(), (peerBlockSignatures.size() != 1 ? "s" : "")));
+			}
+
+			latestPeerSignature = peerBlockSignatures.get(0);
+			peerBlockSignatures.remove(0);
+			++ourHeight;
+
+			Block newBlock = this.fetchBlock(repository, peer, latestPeerSignature);
+
+			if (newBlock == null) {
+				LOGGER.info(String.format("Peer %s failed to respond with block for height %d, sig %.8s", peer,
+						ourHeight, Base58.encode(latestPeerSignature)));
+				return SynchronizationResult.NO_REPLY;
+			}
+
+			if (!newBlock.isSignatureValid()) {
+				LOGGER.info(String.format("Peer %s sent block with invalid signature for height %d, sig %.8s", peer,
+						ourHeight, Base58.encode(latestPeerSignature)));
+				return SynchronizationResult.INVALID_DATA;
+			}
+
+			// Transactions are transmitted without approval status so determine that now
+			for (Transaction transaction : newBlock.getTransactions())
+				transaction.setInitialApprovalStatus();
+
+			ValidationResult blockResult = newBlock.isValid();
+			if (blockResult != ValidationResult.OK) {
+				LOGGER.info(String.format("Peer %s sent invalid block for height %d, sig %.8s: %s", peer,
+						ourHeight, Base58.encode(latestPeerSignature), blockResult.name()));
+				return SynchronizationResult.INVALID_DATA;
+			}
+
+			// Save transactions attached to this block
+			for (Transaction transaction : newBlock.getTransactions()) {
+				TransactionData transactionData = transaction.getTransactionData();
+				repository.getTransactionRepository().save(transactionData);
+			}
+
+			newBlock.process();
+
+			// If we've grown our blockchain then at least save progress so far
+			if (ourHeight > ourInitialHeight)
+				repository.saveChanges();
+		}
+
+		return SynchronizationResult.OK;
+	}
+
 	private List<BlockSummaryData> getBlockSummaries(Peer peer, byte[] parentSignature, int numberRequested) throws InterruptedException {
 		Message getBlockSummariesMessage = new GetBlockSummariesMessage(parentSignature, numberRequested);
 

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

@@ -1,28 +1,45 @@
 package org.qortal.crosschain;
 
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 import java.util.stream.Collectors;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.bitcoinj.core.Address;
 import org.bitcoinj.core.Coin;
+import org.bitcoinj.core.ECKey;
+import org.bitcoinj.core.InsufficientMoneyException;
+import org.bitcoinj.core.LegacyAddress;
 import org.bitcoinj.core.NetworkParameters;
+import org.bitcoinj.core.Sha256Hash;
 import org.bitcoinj.core.Transaction;
 import org.bitcoinj.core.TransactionOutput;
+import org.bitcoinj.core.UTXO;
+import org.bitcoinj.core.UTXOProvider;
+import org.bitcoinj.core.UTXOProviderException;
+import org.bitcoinj.crypto.DeterministicHierarchy;
+import org.bitcoinj.crypto.DeterministicKey;
 import org.bitcoinj.params.MainNetParams;
 import org.bitcoinj.params.RegTestParams;
 import org.bitcoinj.params.TestNet3Params;
+import org.bitcoinj.script.Script.ScriptType;
 import org.bitcoinj.script.ScriptBuilder;
 import org.bitcoinj.utils.MonetaryFormat;
+import org.bitcoinj.wallet.DeterministicKeyChain;
+import org.bitcoinj.wallet.SendRequest;
+import org.bitcoinj.wallet.Wallet;
+import org.qortal.crosschain.ElectrumX.UnspentOutput;
+import org.qortal.crypto.Crypto;
 import org.qortal.settings.Settings;
 import org.qortal.utils.BitTwiddling;
-import org.qortal.utils.Pair;
+
+import com.google.common.hash.HashCode;
 
 public class BTC {
 
-	public static final MonetaryFormat FORMAT = new MonetaryFormat().minDecimals(8).postfixCode();
 	public static final long NO_LOCKTIME_NO_RBF_SEQUENCE = 0xFFFFFFFFL;
 	public static final long LOCKTIME_NO_RBF_SEQUENCE = NO_LOCKTIME_NO_RBF_SEQUENCE - 1;
 	public static final int HASH160_LENGTH = 20;
@@ -30,6 +47,7 @@ public class BTC {
 	protected static final Logger LOGGER = LogManager.getLogger(BTC.class);
 
 	private static final int TIMESTAMP_OFFSET = 4 + 32 + 32;
+	private static final MonetaryFormat FORMAT = new MonetaryFormat().minDecimals(8).postfixCode();
 
 	public enum BitcoinNet {
 		MAIN {
@@ -58,6 +76,9 @@ public class BTC {
 	private final NetworkParameters params;
 	private final ElectrumX electrumX;
 
+	// Let ECKey.equals() do the hard work
+	private final Set<ECKey> spentKeys = new HashSet<>();
+
 	// Constructors and instance
 
 	private BTC() {
@@ -88,6 +109,34 @@ public class BTC {
 
 	// Actual useful methods for use by other classes
 
+	public static String format(Coin amount) {
+		return BTC.FORMAT.format(amount).toString();
+	}
+
+	public static String format(long amount) {
+		return format(Coin.valueOf(amount));
+	}
+
+	public boolean isValidXprv(String xprv58) {
+		try {
+			DeterministicKey.deserializeB58(null, xprv58, this.params);
+			return true;
+		} catch (IllegalArgumentException e) {
+			return false;
+		}
+	}
+
+	/** Returns P2PKH Bitcoin address using passed public key hash. */
+	public String pkhToAddress(byte[] publicKeyHash) {
+		return LegacyAddress.fromPubKeyHash(this.params, publicKeyHash).toString();
+	}
+
+	public String deriveP2shAddress(byte[] redeemScriptBytes) {
+		byte[] redeemScriptHash = Crypto.hash160(redeemScriptBytes);
+		Address p2shAddress = LegacyAddress.fromScriptHash(params, redeemScriptHash);
+		return p2shAddress.toString();
+	}
+
 	/** Returns median timestamp from latest 11 blocks, in seconds. */
 	public Integer getMedianBlockTime() {
 		Integer height = this.electrumX.getCurrentHeight();
@@ -99,34 +148,31 @@ public class BTC {
 		if (blockHeaders == null || blockHeaders.size() < 11)
 			return null;
 
-		List<Integer> blockTimestamps = blockHeaders.stream().map(blockHeader -> BitTwiddling.fromLEBytes(blockHeader, TIMESTAMP_OFFSET)).collect(Collectors.toList());
+		List<Integer> blockTimestamps = blockHeaders.stream().map(blockHeader -> BitTwiddling.intFromLEBytes(blockHeader, TIMESTAMP_OFFSET)).collect(Collectors.toList());
 
-		// Descending, but order shouldn't matter as we're picking median...
+		// Descending order
 		blockTimestamps.sort((a, b) -> Integer.compare(b, a));
 
+		// Pick median
 		return blockTimestamps.get(5);
 	}
 
-	public Coin getBalance(String base58Address) {
-		Long balance = this.electrumX.getBalance(addressToScript(base58Address));
-		if (balance == null)
-			return null;
-
-		return Coin.valueOf(balance);
+	public Long getBalance(String base58Address) {
+		return this.electrumX.getBalance(addressToScript(base58Address));
 	}
 
 	public List<TransactionOutput> getUnspentOutputs(String base58Address) {
-		List<Pair<byte[], Integer>> unspentOutputs = this.electrumX.getUnspentOutputs(addressToScript(base58Address));
+		List<UnspentOutput> unspentOutputs = this.electrumX.getUnspentOutputs(addressToScript(base58Address));
 		if (unspentOutputs == null)
 			return null;
 
 		List<TransactionOutput> unspentTransactionOutputs = new ArrayList<>();
-		for (Pair<byte[], Integer> unspentOutput : unspentOutputs) {
-			List<TransactionOutput> transactionOutputs = getOutputs(unspentOutput.getA());
+		for (UnspentOutput unspentOutput : unspentOutputs) {
+			List<TransactionOutput> transactionOutputs = getOutputs(unspentOutput.hash);
 			if (transactionOutputs == null)
 				return null;
 
-			unspentTransactionOutputs.add(transactionOutputs.get(unspentOutput.getB()));
+			unspentTransactionOutputs.add(transactionOutputs.get(unspentOutput.index));
 		}
 
 		return unspentTransactionOutputs;
@@ -141,6 +187,7 @@ public class BTC {
 		return transaction.getOutputs();
 	}
 
+	/** Returns list of raw transactions spending passed address. */
 	public List<byte[]> getAddressTransactions(String base58Address) {
 		return this.electrumX.getAddressTransactions(addressToScript(base58Address));
 	}
@@ -149,6 +196,181 @@ public class BTC {
 		return this.electrumX.broadcastTransaction(transaction.bitcoinSerialize());
 	}
 
+	/**
+	 * Returns bitcoinj transaction sending <tt>amount</tt> to <tt>recipient</tt>.
+	 * 
+	 * @param xprv58 BIP32 extended Bitcoin private key
+	 * @param recipient P2PKH address
+	 * @param amount unscaled amount
+	 * @return transaction, or null if insufficient funds
+	 */
+	public Transaction buildSpend(String xprv58, String recipient, long amount) {
+		Wallet wallet = Wallet.fromSpendingKeyB58(this.params, xprv58, DeterministicHierarchy.BIP32_STANDARDISATION_TIME_SECS);
+		wallet.setUTXOProvider(new WalletAwareUTXOProvider(this, wallet, WalletAwareUTXOProvider.KeySearchMode.REQUEST_MORE_IF_ALL_SPENT));
+
+		Address destination = Address.fromString(this.params, recipient);
+		SendRequest sendRequest = SendRequest.to(destination, Coin.valueOf(amount));
+
+		if (this.params == TestNet3Params.get())
+			// Much smaller fee for TestNet3
+			sendRequest.feePerKb = Coin.valueOf(2000L);
+
+		try {
+			wallet.completeTx(sendRequest);
+			return sendRequest.tx;
+		} catch (InsufficientMoneyException e) {
+			return null;
+		}
+	}
+
+	/**
+	 * Returns unspent Bitcoin balance given 'm' BIP32 key.
+	 *
+	 * @param xprv58 BIP32 extended Bitcoin private key
+	 * @return unspent BTC balance, or null if unable to determine balance
+	 */
+	public Long getWalletBalance(String xprv58) {
+		Wallet wallet = Wallet.fromSpendingKeyB58(this.params, xprv58, DeterministicHierarchy.BIP32_STANDARDISATION_TIME_SECS);
+		wallet.setUTXOProvider(new WalletAwareUTXOProvider(this, wallet, WalletAwareUTXOProvider.KeySearchMode.REQUEST_MORE_IF_ANY_SPENT));
+
+		Coin balance = wallet.getBalance();
+		if (balance == null)
+			return null;
+
+		return balance.value;
+	}
+
+	// UTXOProvider support
+
+	static class WalletAwareUTXOProvider implements UTXOProvider {
+		private static final int LOOKAHEAD_INCREMENT = 3;
+
+		private final BTC btc;
+		private final Wallet wallet;
+
+		enum KeySearchMode {
+			REQUEST_MORE_IF_ALL_SPENT, REQUEST_MORE_IF_ANY_SPENT;
+		}
+		private final KeySearchMode keySearchMode;
+		private final DeterministicKeyChain keyChain;
+
+		public WalletAwareUTXOProvider(BTC btc, Wallet wallet, KeySearchMode keySearchMode) {
+			this.btc = btc;
+			this.wallet = wallet;
+			this.keySearchMode = keySearchMode;
+			this.keyChain = this.wallet.getActiveKeyChain();
+
+			// Set up wallet's key chain
+			this.keyChain.setLookaheadSize(LOOKAHEAD_INCREMENT);
+			this.keyChain.maybeLookAhead();
+		}
+
+		public List<UTXO> getOpenTransactionOutputs(List<ECKey> keys) throws UTXOProviderException {
+			List<UTXO> allUnspentOutputs = new ArrayList<>();
+			final boolean coinbase = false;
+
+			int ki = 0;
+			do {
+				boolean areAllKeysUnspent = true;
+				boolean areAllKeysSpent = true;
+
+				for (; ki < keys.size(); ++ki) {
+					ECKey key = keys.get(ki);
+
+					Address address = Address.fromKey(btc.params, key, ScriptType.P2PKH);
+					byte[] script = ScriptBuilder.createOutputScript(address).getProgram();
+
+					List<UnspentOutput> unspentOutputs = btc.electrumX.getUnspentOutputs(script);
+					if (unspentOutputs == null)
+						throw new UTXOProviderException(String.format("Unable to fetch unspent outputs for %s", address));
+
+					/*
+					 * If there are no unspent outputs then either:
+					 * a) all the outputs have been spent
+					 * b) address has never been used
+					 * 
+					 * For case (a) we want to remember not to check this address (key) again.
+					 */
+
+					if (unspentOutputs.isEmpty()) {
+						// If this is a known key that has been spent before, then we can skip asking for transaction history
+						if (btc.spentKeys.contains(key)) {
+							wallet.getActiveKeyChain().markKeyAsUsed((DeterministicKey) key);
+							areAllKeysUnspent = false;
+							continue;
+						}
+
+						// Ask for transaction history - if it's empty then key has never been used
+						List<byte[]> historicTransactionHashes = btc.electrumX.getAddressTransactions(script);
+						if (historicTransactionHashes == null)
+							throw new UTXOProviderException(
+									String.format("Unable to fetch transaction history for %s", address));
+
+						if (!historicTransactionHashes.isEmpty()) {
+							// Fully spent key - case (a)
+							btc.spentKeys.add(key);
+							wallet.getActiveKeyChain().markKeyAsUsed((DeterministicKey) key);
+							areAllKeysUnspent = false;
+						} else {
+							// Key never been used - case (b)
+							areAllKeysSpent = false;
+						}
+
+						continue;
+					}
+
+					// If we reach here, then there's definitely at least one unspent key
+					areAllKeysSpent = false;
+
+					for (UnspentOutput unspentOutput : unspentOutputs) {
+						List<TransactionOutput> transactionOutputs = btc.getOutputs(unspentOutput.hash);
+						if (transactionOutputs == null)
+							throw new UTXOProviderException(String.format("Unable to fetch outputs for TX %s",
+									HashCode.fromBytes(unspentOutput.hash)));
+
+						TransactionOutput transactionOutput = transactionOutputs.get(unspentOutput.index);
+
+						UTXO utxo = new UTXO(Sha256Hash.wrap(unspentOutput.hash), unspentOutput.index,
+								Coin.valueOf(unspentOutput.value), unspentOutput.height, coinbase,
+								transactionOutput.getScriptPubKey());
+
+						allUnspentOutputs.add(utxo);
+					}
+				}
+
+				if ((this.keySearchMode == KeySearchMode.REQUEST_MORE_IF_ALL_SPENT && areAllKeysSpent)
+						|| (this.keySearchMode == KeySearchMode.REQUEST_MORE_IF_ANY_SPENT && !areAllKeysUnspent)) {
+					// Generate some more keys
+					this.keyChain.setLookaheadSize(this.keyChain.getLookaheadSize() + LOOKAHEAD_INCREMENT);
+					this.keyChain.maybeLookAhead();
+
+					// This returns all keys, including those already in 'keys'
+					List<DeterministicKey> allLeafKeys = this.keyChain.getLeafKeys();
+					// Add only new keys onto our list of keys to search
+					List<DeterministicKey> newKeys = allLeafKeys.subList(ki, allLeafKeys.size());
+					keys.addAll(newKeys);
+					// Fall-through to checking more keys as now 'ki' is smaller than 'keys.size()' again
+				}
+
+				// If we have processed all keys, then we're done
+			} while (ki < keys.size());
+
+			return allUnspentOutputs;
+		}
+
+		public int getChainHeadHeight() throws UTXOProviderException {
+			Integer height = btc.electrumX.getCurrentHeight();
+			if (height == null)
+				throw new UTXOProviderException("Unable to determine Bitcoin chain height");
+
+			return height.intValue();
+		}
+
+		public NetworkParameters getParams() {
+			return btc.params;
+		}
+	}
+
 	// Utility methods for us
 
 	private byte[] addressToScript(String base58Address) {

src/main/java/org/qortal/crosschain/BTCP2SH.java

@@ -0,0 +1,236 @@
+package org.qortal.crosschain;
+
+import java.util.List;
+import java.util.function.Function;
+
+import org.bitcoinj.core.Address;
+import org.bitcoinj.core.Coin;
+import org.bitcoinj.core.ECKey;
+import org.bitcoinj.core.LegacyAddress;
+import org.bitcoinj.core.NetworkParameters;
+import org.bitcoinj.core.Transaction;
+import org.bitcoinj.core.Transaction.SigHash;
+import org.bitcoinj.core.TransactionInput;
+import org.bitcoinj.core.TransactionOutput;
+import org.bitcoinj.crypto.TransactionSignature;
+import org.bitcoinj.script.Script;
+import org.bitcoinj.script.ScriptBuilder;
+import org.bitcoinj.script.ScriptChunk;
+import org.bitcoinj.script.ScriptOpCodes;
+import org.qortal.crypto.Crypto;
+import org.qortal.utils.BitTwiddling;
+
+import com.google.common.hash.HashCode;
+import com.google.common.primitives.Bytes;
+
+public class BTCP2SH {
+
+	public static final int SECRET_LENGTH = 32;
+	public static final int MIN_LOCKTIME = 1500000000;
+
+	/*
+	 * OP_TUCK (to copy public key to before signature)
+	 * OP_CHECKSIGVERIFY (sig & pubkey must verify or script fails)
+	 * OP_HASH160 (convert public key to PKH)
+	 * OP_DUP (duplicate PKH)
+	 * <push 20 bytes> <refund PKH> OP_EQUAL (does PKH match refund PKH?)
+	 * OP_IF
+	 * 	OP_DROP (no need for duplicate PKH)
+	 * 	<push 4 bytes> <locktime>
+	 * 	OP_CHECKLOCKTIMEVERIFY (if this passes, leftover stack is <locktime> so script passes)
+	 * OP_ELSE
+	 * 	<push 20 bytes> <redeem PKH> OP_EQUALVERIFY (duplicate PKH must match redeem PKH or script fails)
+	 * 	OP_HASH160 (hash secret)
+	 * 	<push 20 bytes> <hash of secret> OP_EQUAL (do hashes of secrets match? if true, script passes else script fails)
+	 * OP_ENDIF
+	 */
+
+	private static final byte[] redeemScript1 = HashCode.fromString("7dada97614").asBytes(); // OP_TUCK OP_CHECKSIGVERIFY OP_HASH160 OP_DUP push(0x14 bytes)
+	private static final byte[] redeemScript2 = HashCode.fromString("87637504").asBytes(); // OP_EQUAL OP_IF OP_DROP push(0x4 bytes)
+	private static final byte[] redeemScript3 = HashCode.fromString("b16714").asBytes(); // OP_CHECKLOCKTIMEVERIFY OP_ELSE push(0x14 bytes)
+	private static final byte[] redeemScript4 = HashCode.fromString("88a914").asBytes(); // OP_EQUALVERIFY OP_HASH160 push(0x14 bytes)
+	private static final byte[] redeemScript5 = HashCode.fromString("8768").asBytes(); // OP_EQUAL OP_ENDIF
+
+	/**
+	 * Returns Bitcoin redeemScript used for cross-chain trading.
+	 * <p>
+	 * See comments in {@link BTCP2SH} for more details.
+	 * 
+	 * @param refunderPubKeyHash 20-byte HASH160 of P2SH funder's public key, for refunding purposes
+	 * @param lockTime seconds-since-epoch threshold, after which P2SH funder can claim refund
+	 * @param redeemerPubKeyHash 20-byte HASH160 of P2SH redeemer's public key
+	 * @param secretHash 20-byte HASH160 of secret, used by P2SH redeemer to claim funds
+	 * @return
+	 */
+	public static byte[] buildScript(byte[] refunderPubKeyHash, int lockTime, byte[] redeemerPubKeyHash, byte[] secretHash) {
+		return Bytes.concat(redeemScript1, refunderPubKeyHash, redeemScript2, BitTwiddling.toLEByteArray((int) (lockTime & 0xffffffffL)),
+				redeemScript3, redeemerPubKeyHash, redeemScript4, secretHash, redeemScript5);
+	}
+
+	/**
+	 * Builds a custom transaction to spend P2SH.
+	 * 
+	 * @param amount output amount, should be total of input amounts, less miner fees
+	 * @param spendKey key for signing transaction, and also where funds are 'sent' (output)
+	 * @param fundingOutput output from transaction that funded P2SH address
+	 * @param redeemScriptBytes the redeemScript itself, in byte[] form
+	 * @param lockTime (optional) transaction nLockTime, used in refund scenario
+	 * @param scriptSigBuilder function for building scriptSig using transaction input signature
+	 * @param outputPublicKeyHash PKH used to create P2PKH output
+	 * @return Signed Bitcoin transaction for spending P2SH
+	 */
+	public static Transaction buildP2shTransaction(Coin amount, ECKey spendKey, List<TransactionOutput> fundingOutputs, byte[] redeemScriptBytes,
+			Long lockTime, Function<byte[], Script> scriptSigBuilder, byte[] outputPublicKeyHash) {
+		NetworkParameters params = BTC.getInstance().getNetworkParameters();
+
+		Transaction transaction = new Transaction(params);
+		transaction.setVersion(2);
+
+		// Output is back to P2SH funder
+		transaction.addOutput(amount, ScriptBuilder.createP2PKHOutputScript(outputPublicKeyHash));
+
+		for (int inputIndex = 0; inputIndex < fundingOutputs.size(); ++inputIndex) {
+			TransactionOutput fundingOutput = fundingOutputs.get(inputIndex);
+
+			// Input (without scriptSig prior to signing)
+			TransactionInput input = new TransactionInput(params, null, redeemScriptBytes, fundingOutput.getOutPointFor());
+			if (lockTime != null)
+				input.setSequenceNumber(BTC.LOCKTIME_NO_RBF_SEQUENCE); // Use max-value - 1, so lockTime can be used but not RBF
+			else
+				input.setSequenceNumber(BTC.NO_LOCKTIME_NO_RBF_SEQUENCE); // Use max-value, so no lockTime and no RBF
+			transaction.addInput(input);
+		}
+
+		// Set locktime after inputs added but before input signatures are generated
+		if (lockTime != null)
+			transaction.setLockTime(lockTime);
+
+		for (int inputIndex = 0; inputIndex < fundingOutputs.size(); ++inputIndex) {
+			// Generate transaction signature for input
+			final boolean anyoneCanPay = false;
+			TransactionSignature txSig = transaction.calculateSignature(inputIndex, spendKey, redeemScriptBytes, SigHash.ALL, anyoneCanPay);
+
+			// Calculate transaction signature
+			byte[] txSigBytes = txSig.encodeToBitcoin();
+
+			// Build scriptSig using lambda and tx signature
+			Script scriptSig = scriptSigBuilder.apply(txSigBytes);
+
+			// Set input scriptSig
+			transaction.getInput(inputIndex).setScriptSig(scriptSig);
+		}
+
+		return transaction;
+	}
+
+	/**
+	 * Returns signed Bitcoin transaction claiming refund from P2SH address.
+	 * 
+	 * @param refundAmount refund amount, should be total of input amounts, less miner fees
+	 * @param refundKey key for signing transaction, and also where refund is 'sent' (output)
+	 * @param fundingOutput output from transaction that funded P2SH address
+	 * @param redeemScriptBytes the redeemScript itself, in byte[] form
+	 * @param lockTime transaction nLockTime - must be at least locktime used in redeemScript
+	 * @return Signed Bitcoin transaction for refunding P2SH
+	 */
+	public static Transaction buildRefundTransaction(Coin refundAmount, ECKey refundKey, List<TransactionOutput> fundingOutputs, byte[] redeemScriptBytes, long lockTime) {
+		Function<byte[], Script> refundSigScriptBuilder = (txSigBytes) -> {
+			// Build scriptSig with...
+			ScriptBuilder scriptBuilder = new ScriptBuilder();
+
+			// transaction signature
+			scriptBuilder.addChunk(new ScriptChunk(txSigBytes.length, txSigBytes));
+
+			// redeem public key
+			byte[] refundPubKey = refundKey.getPubKey();
+			scriptBuilder.addChunk(new ScriptChunk(refundPubKey.length, refundPubKey));
+
+			// redeem script
+			scriptBuilder.addChunk(new ScriptChunk(ScriptOpCodes.OP_PUSHDATA1, redeemScriptBytes));
+
+			return scriptBuilder.build();
+		};
+
+		// Send funds back to funding address
+		return buildP2shTransaction(refundAmount, refundKey, fundingOutputs, redeemScriptBytes, lockTime, refundSigScriptBuilder, refundKey.getPubKeyHash());
+	}
+
+	/**
+	 * Returns signed Bitcoin transaction redeeming funds from P2SH address.
+	 * 
+	 * @param redeemAmount redeem amount, should be total of input amounts, less miner fees
+	 * @param redeemKey key for signing transaction, and also where funds are 'sent' (output)
+	 * @param fundingOutput output from transaction that funded P2SH address
+	 * @param redeemScriptBytes the redeemScript itself, in byte[] form
+	 * @param secret actual 32-byte secret used when building redeemScript
+	 * @param receivingAccountInfo Bitcoin PKH used for output
+	 * @return Signed Bitcoin transaction for redeeming P2SH
+	 */
+	public static Transaction buildRedeemTransaction(Coin redeemAmount, ECKey redeemKey, List<TransactionOutput> fundingOutputs, byte[] redeemScriptBytes, byte[] secret, byte[] receivingAccountInfo) {
+		Function<byte[], Script> redeemSigScriptBuilder = (txSigBytes) -> {
+			// Build scriptSig with...
+			ScriptBuilder scriptBuilder = new ScriptBuilder();
+
+			// secret
+			scriptBuilder.addChunk(new ScriptChunk(secret.length, secret));
+
+			// transaction signature
+			scriptBuilder.addChunk(new ScriptChunk(txSigBytes.length, txSigBytes));
+
+			// redeem public key
+			byte[] redeemPubKey = redeemKey.getPubKey();
+			scriptBuilder.addChunk(new ScriptChunk(redeemPubKey.length, redeemPubKey));
+
+			// redeem script
+			scriptBuilder.addChunk(new ScriptChunk(ScriptOpCodes.OP_PUSHDATA1, redeemScriptBytes));
+
+			return scriptBuilder.build();
+		};
+
+		return buildP2shTransaction(redeemAmount, redeemKey, fundingOutputs, redeemScriptBytes, null, redeemSigScriptBuilder, receivingAccountInfo);
+	}
+
+	/** Returns 'secret', if any, given list of raw bitcoin transactions. */
+	public static byte[] findP2shSecret(String p2shAddress, List<byte[]> rawTransactions) {
+		NetworkParameters params = BTC.getInstance().getNetworkParameters();
+
+		for (byte[] rawTransaction : rawTransactions) {
+			Transaction transaction = new Transaction(params, rawTransaction);
+
+			// Cycle through inputs, looking for one that spends our P2SH
+			for (TransactionInput input : transaction.getInputs()) {
+				Script scriptSig = input.getScriptSig();
+				List<ScriptChunk> scriptChunks = scriptSig.getChunks();
+
+				// Expected number of script chunks for redeem. Refund might not have the same number.
+				int expectedChunkCount = 1 /*secret*/ + 1 /*sig*/ + 1 /*pubkey*/ + 1 /*redeemScript*/;
+				if (scriptChunks.size() != expectedChunkCount)
+					continue;
+
+				// We're expecting last chunk to contain the actual redeemScript
+				ScriptChunk lastChunk = scriptChunks.get(scriptChunks.size() - 1);
+				byte[] redeemScriptBytes = lastChunk.data;
+
+				// If non-push scripts, redeemScript will be null
+				if (redeemScriptBytes == null)
+					continue;
+
+				byte[] redeemScriptHash = Crypto.hash160(redeemScriptBytes);
+				Address inputAddress = LegacyAddress.fromScriptHash(params, redeemScriptHash);
+
+				if (!inputAddress.toString().equals(p2shAddress))
+					// Input isn't spending our P2SH
+					continue;
+
+				byte[] secret = scriptChunks.get(0).data;
+				if (secret.length != BTCP2SH.SECRET_LENGTH)
+					continue;
+
+				return secret;
+			}
+		}
+
+		return null;
+	}
+
+}

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

@@ -25,11 +25,11 @@ import org.json.simple.JSONObject;
 import org.json.simple.JSONValue;
 import org.qortal.crypto.Crypto;
 import org.qortal.crypto.TrustlessSSLSocketFactory;
-import org.qortal.utils.Pair;
 
 import com.google.common.hash.HashCode;
 import com.google.common.primitives.Bytes;
 
+/** ElectrumX network support for querying Bitcoin-related info like block headers, transaction outputs, etc. */
 public class ElectrumX {
 
 	private static final Logger LOGGER = LogManager.getLogger(ElectrumX.class);
@@ -93,7 +93,21 @@ public class ElectrumX {
 	private ElectrumX(String bitcoinNetwork) {
 		switch (bitcoinNetwork) {
 			case "MAIN":
-				servers.addAll(Arrays.asList());
+				servers.addAll(Arrays.asList(
+						// Servers chosen on NO BASIS WHATSOEVER from various sources!
+						new Server("tardis.bauerj.eu", Server.ConnectionType.SSL, 50002),
+						new Server("rbx.curalle.ovh", Server.ConnectionType.SSL, 50002),
+						new Server("quick.electumx.live", Server.ConnectionType.SSL, 50002),
+						new Server("enode.duckdns.org", Server.ConnectionType.SSL, 50002),
+						new Server("electrumx.ddns.net", Server.ConnectionType.SSL, 50002),
+						new Server("electrumx.ml", Server.ConnectionType.SSL, 50002),
+						new Server("electrum.eff.ro", Server.ConnectionType.SSL, 50002),
+						new Server("electrum.bitkoins.nl", Server.ConnectionType.SSL, 50512),
+						new Server("E-X.not.fyi", Server.ConnectionType.SSL, 50002),
+						new Server("btc.electroncash.dk", Server.ConnectionType.SSL, 60002),
+						new Server("electrum.blockstream.info", Server.ConnectionType.TCP, 50001),
+						new Server("electrum.blockstream.info", Server.ConnectionType.SSL, 50002),
+						new Server("bitcoin.aranguren.org", Server.ConnectionType.TCP, 50001)));
 				break;
 
 			case "TEST3":
@@ -119,6 +133,7 @@ public class ElectrumX {
 		rpc("server.banner");
 	}
 
+	/** Returns ElectrumX instance linked to passed Bitcoin network, one of "MAIN", "TEST3" or "REGTEST". */
 	public static synchronized ElectrumX getInstance(String bitcoinNetwork) {
 		if (!instances.containsKey(bitcoinNetwork))
 			instances.put(bitcoinNetwork, new ElectrumX(bitcoinNetwork));
@@ -129,16 +144,26 @@ public class ElectrumX {
 	// Methods for use by other classes
 
 	public Integer getCurrentHeight() {
-		JSONObject blockJson = (JSONObject) this.rpc("blockchain.headers.subscribe");
-		if (blockJson == null || !blockJson.containsKey("height"))
+		Object blockObj = this.rpc("blockchain.headers.subscribe");
+		if (!(blockObj instanceof JSONObject))
+			return null;
+
+		JSONObject blockJson = (JSONObject) blockObj;
+
+		if (!blockJson.containsKey("height"))
 			return null;
 
 		return ((Long) blockJson.get("height")).intValue();
 	}
 
 	public List<byte[]> getBlockHeaders(int startHeight, long count) {
-		JSONObject blockJson = (JSONObject) this.rpc("blockchain.block.headers", startHeight, count);
-		if (blockJson == null || !blockJson.containsKey("count") || !blockJson.containsKey("hex"))
+		Object blockObj = this.rpc("blockchain.block.headers", startHeight, count);
+		if (!(blockObj instanceof JSONObject))
+			return null;
+
+		JSONObject blockJson = (JSONObject) blockObj;
+
+		if (!blockJson.containsKey("count") || !blockJson.containsKey("hex"))
 			return null;
 
 		Long returnedCount = (Long) blockJson.get("count");
@@ -155,57 +180,87 @@ public class ElectrumX {
 		return rawBlockHeaders;
 	}
 
+	/** Returns confirmed balance, based on passed payment script, or null if there was an error or no known balance. */
 	public Long getBalance(byte[] script) {
 		byte[] scriptHash = Crypto.digest(script);
 		Bytes.reverse(scriptHash);
 
-		JSONObject balanceJson = (JSONObject) this.rpc("blockchain.scripthash.get_balance", HashCode.fromBytes(scriptHash).toString());
-		if (balanceJson == null || !balanceJson.containsKey("confirmed"))
+		Object balanceObj = this.rpc("blockchain.scripthash.get_balance", HashCode.fromBytes(scriptHash).toString());
+		if (!(balanceObj instanceof JSONObject))
+			return null;
+
+		JSONObject balanceJson = (JSONObject) balanceObj;
+
+		if (!balanceJson.containsKey("confirmed"))
 			return null;
 
 		return (Long) balanceJson.get("confirmed");
 	}
 
-	public List<Pair<byte[], Integer>> getUnspentOutputs(byte[] script) {
+	/** Unspent output info as returned by ElectrumX network. */
+	public static class UnspentOutput {
+		public final byte[] hash;
+		public final int index;
+		public final int height;
+		public final long value;
+
+		public UnspentOutput(byte[] hash, int index, int height, long value) {
+			this.hash = hash;
+			this.index = index;
+			this.height = height;
+			this.value = value;
+		}
+	}
+
+	/** Returns list of unspent outputs pertaining to passed payment script, or null if there was an error. */
+	public List<UnspentOutput> getUnspentOutputs(byte[] script) {
 		byte[] scriptHash = Crypto.digest(script);
 		Bytes.reverse(scriptHash);
 
-		JSONArray unspentJson = (JSONArray) this.rpc("blockchain.scripthash.listunspent", HashCode.fromBytes(scriptHash).toString());
-		if (unspentJson == null)
+		Object unspentJson = this.rpc("blockchain.scripthash.listunspent", HashCode.fromBytes(scriptHash).toString());
+		if (!(unspentJson instanceof JSONArray))
 			return null;
 
-		List<Pair<byte[], Integer>> unspentOutputs = new ArrayList<>();
-		for (Object rawUnspent : unspentJson) {
+		List<UnspentOutput> unspentOutputs = new ArrayList<>();
+		for (Object rawUnspent : (JSONArray) unspentJson) {
 			JSONObject unspent = (JSONObject) rawUnspent;
 
+			int height = ((Long) unspent.get("height")).intValue();
+			// We only want unspent outputs from confirmed transactions (and definitely not mempool duplicates with height 0)
+			if (height <= 0)
+				continue;
+
 			byte[] txHash = HashCode.fromString((String) unspent.get("tx_hash")).asBytes();
 			int outputIndex = ((Long) unspent.get("tx_pos")).intValue();
+			long value = (Long) unspent.get("value");
 
-			unspentOutputs.add(new Pair<>(txHash, outputIndex));
+			unspentOutputs.add(new UnspentOutput(txHash, outputIndex, height, value));
 		}
 
 		return unspentOutputs;
 	}
 
+	/** Returns raw transaction for passed transaction hash, or null if not found. */
 	public byte[] getRawTransaction(byte[] txHash) {
-		String rawTransactionHex = (String) this.rpc("blockchain.transaction.get", HashCode.fromBytes(txHash).toString());
-		if (rawTransactionHex == null)
+		Object rawTransactionHex = this.rpc("blockchain.transaction.get", HashCode.fromBytes(txHash).toString());
+		if (!(rawTransactionHex instanceof String))
 			return null;
 
-		return HashCode.fromString(rawTransactionHex).asBytes();
+		return HashCode.fromString((String) rawTransactionHex).asBytes();
 	}
 
+	/** Returns list of raw transactions, relating to passed payment script, if null if there's an error. */
 	public List<byte[]> getAddressTransactions(byte[] script) {
 		byte[] scriptHash = Crypto.digest(script);
 		Bytes.reverse(scriptHash);
 
-		JSONArray transactionsJson = (JSONArray) this.rpc("blockchain.scripthash.get_history", HashCode.fromBytes(scriptHash).toString());
-		if (transactionsJson == null)
+		Object transactionsJson = this.rpc("blockchain.scripthash.get_history", HashCode.fromBytes(scriptHash).toString());
+		if (!(transactionsJson instanceof JSONArray))
 			return null;
 
 		List<byte[]> rawTransactions = new ArrayList<>();
 
-		for (Object rawTransactionInfo : transactionsJson) {
+		for (Object rawTransactionInfo : (JSONArray) transactionsJson) {
 			JSONObject transactionInfo = (JSONObject) rawTransactionInfo;
 
 			// We only want confirmed transactions
@@ -223,6 +278,7 @@ public class ElectrumX {
 		return rawTransactions;
 	}
 
+	/** Returns true if raw transaction successfully broadcast. */
 	public boolean broadcastTransaction(byte[] transactionBytes) {
 		Object rawBroadcastResult = this.rpc("blockchain.transaction.broadcast", HashCode.fromBytes(transactionBytes).toString());
 		if (rawBroadcastResult == null)
@@ -235,14 +291,15 @@ public class ElectrumX {
 
 	// Class-private utility methods
 
+	/** Query current server for its list of peer servers, and return those we can parse. */
 	private Set<Server> serverPeersSubscribe() {
 		Set<Server> newServers = new HashSet<>();
 
-		JSONArray peers = (JSONArray) this.connectedRpc("server.peers.subscribe");
-		if (peers == null)
+		Object peers = this.connectedRpc("server.peers.subscribe");
+		if (!(peers instanceof JSONArray))
 			return newServers;
 
-		for (Object rawPeer : peers) {
+		for (Object rawPeer : (JSONArray) peers) {
 			JSONArray peer = (JSONArray) rawPeer;
 			if (peer.size() < 3)
 				continue;
@@ -287,6 +344,7 @@ public class ElectrumX {
 		return newServers;
 	}
 
+	/** Return output from RPC call, with automatic reconnection to different server if needed. */
 	private synchronized Object rpc(String method, Object...params) {
 		while (haveConnection()) {
 			Object response = connectedRpc(method, params);
@@ -305,6 +363,7 @@ public class ElectrumX {
 		return null;
 	}
 
+	/** Returns true if we have, or create, a connection to an ElectrumX server. */
 	private boolean haveConnection() {
 		if (this.currentServer != null)
 			return true;
@@ -377,10 +436,12 @@ public class ElectrumX {
 		if (response.isEmpty())
 			return null;
 
-		JSONObject responseJson = (JSONObject) JSONValue.parse(response);
-		if (responseJson == null)
+		Object responseObj = JSONValue.parse(response);
+		if (!(responseObj instanceof JSONObject))
 			return null;
 
+		JSONObject responseJson = (JSONObject) responseObj;
+
 		return responseJson.get("result");
 	}
 

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

@@ -1,11 +1,15 @@
 package org.qortal.data.account;
 
+import java.math.BigDecimal;
+
 import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
 import javax.xml.bind.annotation.XmlElement;
 import javax.xml.bind.annotation.XmlTransient;
 import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
 
+import org.qortal.utils.Base58;
+
 import io.swagger.v3.oas.annotations.media.Schema;
 
 // All properties to be converted to JSON via JAXB
@@ -71,4 +75,13 @@ public class RewardShareData {
 		return this.minter;
 	}
 
+	// For debugging
+
+	public String toString() {
+		if (this.minter.equals(this.recipient))
+			return String.format("Minter/recipient: %s, reward-share public key: %s", this.minter, Base58.encode(this.rewardSharePublicKey));
+		else
+			return String.format("Minter: %s, recipient: %s (%s %%), reward-share public key: %s", this.minter, this.recipient, BigDecimal.valueOf(this.sharePercent, 2), Base58.encode(this.rewardSharePublicKey));
+	}
+
 }

src/main/java/org/qortal/data/crosschain/CrossChainTradeData.java

@@ -4,14 +4,14 @@ import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
 import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
 
+import org.qortal.crosschain.BTCACCT;
+
 import io.swagger.v3.oas.annotations.media.Schema;
 
 // All properties to be converted to JSON via JAXB
 @XmlAccessorType(XmlAccessType.FIELD)
 public class CrossChainTradeData {
 
-	public enum Mode { OFFER, TRADE };
-
 	// Properties
 
 	@Schema(description = "AT's Qortal address")
@@ -20,32 +20,40 @@ public class CrossChainTradeData {
 	@Schema(description = "AT creator's Qortal address")
 	public String qortalCreator;
 
+	@Schema(description = "AT creator's Qortal trade address")
+	public String qortalCreatorTradeAddress;
+
+	@Schema(description = "AT creator's Bitcoin trade public-key-hash (PKH)")
+	public byte[] creatorBitcoinPKH;
+
 	@Schema(description = "Timestamp when AT was created (milliseconds since epoch)")
 	public long creationTimestamp;
 
+	@Schema(description = "Suggested trade timeout (minutes)", example = "10080")
+	public int tradeTimeout;
+
 	@Schema(description = "AT's current QORT balance")
 	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
 	public long qortBalance;
 
-	@Schema(description = "HASH160 of 32-byte secret")
-	public byte[] secretHash;
+	@Schema(description = "HASH160 of 32-byte secret-A")
+	public byte[] hashOfSecretA;
 
-	@Schema(description = "Initial QORT payment that will be sent to Qortal trade partner")
-	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
-	public long initialPayout;
+	@Schema(description = "HASH160 of 32-byte secret-B")
+	public byte[] hashOfSecretB;
 
 	@Schema(description = "Final QORT payment that will be sent to Qortal trade partner")
 	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
-	public long redeemPayout;
+	public long qortAmount;
 
 	@Schema(description = "Trade partner's Qortal address (trade begins when this is set)")
-	public String qortalRecipient;
+	public String qortalPartnerAddress;
 
 	@Schema(description = "Timestamp when AT switched to trade mode")
 	public Long tradeModeTimestamp;
 
-	@Schema(description = "How long from beginning trade until AT triggers automatic refund to AT creator (minutes)")
-	public long tradeRefundTimeout;
+	@Schema(description = "How long from AT creation until AT triggers automatic refund to AT creator (minutes)")
+	public Integer refundTimeout;
 
 	@Schema(description = "Actual Qortal block height when AT will automatically refund to AT creator (after trade begins)")
 	public Integer tradeRefundHeight;
@@ -54,10 +62,19 @@ public class CrossChainTradeData {
 	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
 	public long expectedBitcoin;
 
-	public Mode mode;
+	public BTCACCT.Mode mode;
 
-	@Schema(description = "Suggested Bitcoin P2SH nLockTime based on trade timeout")
-	public Integer lockTime;
+	@Schema(description = "Suggested Bitcoin P2SH-A nLockTime based on trade timeout")
+	public Integer lockTimeA;
+
+	@Schema(description = "Suggested Bitcoin P2SH-B nLockTime based on trade timeout")
+	public Integer lockTimeB;
+
+	@Schema(description = "Trade partner's Bitcoin public-key-hash (PKH)")
+	public byte[] partnerBitcoinPKH;
+
+	@Schema(description = "Trade partner's Qortal receiving address")
+	public String qortalPartnerReceivingAddress;
 
 	// Constructors
 

src/main/java/org/qortal/data/crosschain/TradeBotData.java

@@ -0,0 +1,193 @@
+package org.qortal.data.crosschain;
+
+import static java.util.Arrays.stream;
+import static java.util.stream.Collectors.toMap;
+
+import java.util.Map;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+import javax.xml.bind.annotation.XmlTransient;
+import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+
+// All properties to be converted to JSON via JAXB
+@XmlAccessorType(XmlAccessType.FIELD)
+public class TradeBotData {
+
+	private byte[] tradePrivateKey;
+
+	public enum State {
+		BOB_WAITING_FOR_AT_CONFIRM(10), BOB_WAITING_FOR_MESSAGE(15), BOB_WAITING_FOR_P2SH_B(20), BOB_WAITING_FOR_AT_REDEEM(25), BOB_DONE(30), BOB_REFUNDED(35),
+		ALICE_WAITING_FOR_P2SH_A(80), ALICE_WAITING_FOR_AT_LOCK(85), ALICE_WATCH_P2SH_B(90), ALICE_DONE(95), ALICE_REFUNDING_B(100), ALICE_REFUNDING_A(105), ALICE_REFUNDED(110);
+
+		public final int value;
+		private static final Map<Integer, State> map = stream(State.values()).collect(toMap(state -> state.value, state -> state));
+
+		State(int value) {
+			this.value = value;
+		}
+
+		public static State valueOf(int value) {
+			return map.get(value);
+		}
+	}
+	private State tradeState;
+
+	private String creatorAddress;
+	private String atAddress;
+
+	private long timestamp;
+
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long qortAmount;
+
+	private byte[] tradeNativePublicKey;
+	private byte[] tradeNativePublicKeyHash;
+	String tradeNativeAddress;
+
+	private byte[] secret;
+	private byte[] hashOfSecret;
+
+	private byte[] tradeForeignPublicKey;
+	private byte[] tradeForeignPublicKeyHash;
+
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long bitcoinAmount;
+
+	// Never expose this via API
+	@XmlTransient
+	@Schema(hidden = true)
+	private String xprv58;
+
+	private byte[] lastTransactionSignature;
+
+	private Integer lockTimeA;
+
+	// Could be Bitcoin or Qortal...
+	private byte[] receivingAccountInfo;
+
+	protected TradeBotData() {
+		/* JAXB */
+	}
+
+	public TradeBotData(byte[] tradePrivateKey, State tradeState, String creatorAddress, String atAddress,
+			long timestamp, long qortAmount,
+			byte[] tradeNativePublicKey, byte[] tradeNativePublicKeyHash, String tradeNativeAddress,
+			byte[] secret, byte[] hashOfSecret,
+			byte[] tradeForeignPublicKey, byte[] tradeForeignPublicKeyHash,
+			long bitcoinAmount, String xprv58, byte[] lastTransactionSignature, Integer lockTimeA, byte[] receivingAccountInfo) {
+		this.tradePrivateKey = tradePrivateKey;
+		this.tradeState = tradeState;
+		this.creatorAddress = creatorAddress;
+		this.atAddress = atAddress;
+		this.timestamp = timestamp;
+		this.qortAmount = qortAmount;
+		this.tradeNativePublicKey = tradeNativePublicKey;
+		this.tradeNativePublicKeyHash = tradeNativePublicKeyHash;
+		this.tradeNativeAddress = tradeNativeAddress;
+		this.secret = secret;
+		this.hashOfSecret = hashOfSecret;
+		this.tradeForeignPublicKey = tradeForeignPublicKey;
+		this.tradeForeignPublicKeyHash = tradeForeignPublicKeyHash;
+		this.bitcoinAmount = bitcoinAmount;
+		this.xprv58 = xprv58;
+		this.lastTransactionSignature = lastTransactionSignature;
+		this.lockTimeA = lockTimeA;
+		this.receivingAccountInfo = receivingAccountInfo;
+	}
+
+	public byte[] getTradePrivateKey() {
+		return this.tradePrivateKey;
+	}
+
+	public State getState() {
+		return this.tradeState;
+	}
+
+	public void setState(State state) {
+		this.tradeState = state;
+	}
+
+	public String getCreatorAddress() {
+		return this.creatorAddress;
+	}
+
+	public String getAtAddress() {
+		return this.atAddress;
+	}
+
+	public void setAtAddress(String atAddress) {
+		this.atAddress = atAddress;
+	}
+
+	public long getTimestamp() {
+		return this.timestamp;
+	}
+
+	public void setTimestamp(long timestamp) {
+		this.timestamp = timestamp;
+	}
+
+	public long getQortAmount() {
+		return this.qortAmount;
+	}
+
+	public byte[] getTradeNativePublicKey() {
+		return this.tradeNativePublicKey;
+	}
+
+	public byte[] getTradeNativePublicKeyHash() {
+		return this.tradeNativePublicKeyHash;
+	}
+
+	public String getTradeNativeAddress() {
+		return this.tradeNativeAddress;
+	}
+
+	public byte[] getSecret() {
+		return this.secret;
+	}
+
+	public byte[] getHashOfSecret() {
+		return this.hashOfSecret;
+	}
+
+	public byte[] getTradeForeignPublicKey() {
+		return this.tradeForeignPublicKey;
+	}
+
+	public byte[] getTradeForeignPublicKeyHash() {
+		return this.tradeForeignPublicKeyHash;
+	}
+
+	public long getBitcoinAmount() {
+		return this.bitcoinAmount;
+	}
+
+	public String getXprv58() {
+		return this.xprv58;
+	}
+
+	public byte[] getLastTransactionSignature() {
+		return this.lastTransactionSignature;
+	}
+
+	public void setLastTransactionSignature(byte[] lastTransactionSignature) {
+		this.lastTransactionSignature = lastTransactionSignature;
+	}
+
+	public Integer getLockTimeA() {
+		return this.lockTimeA;
+	}
+
+	public void setLockTimeA(Integer lockTimeA) {
+		this.lockTimeA = lockTimeA;
+	}
+
+	public byte[] getReceivingAccountInfo() {
+		return this.receivingAccountInfo;
+	}
+
+}

src/main/java/org/qortal/event/Event.java

@@ -0,0 +1,5 @@
+package org.qortal.event;
+
+public interface Event {
+
+}

src/main/java/org/qortal/event/EventBus.java

@@ -0,0 +1,33 @@
+package org.qortal.event;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public enum EventBus {
+	INSTANCE;
+
+	private static final List<Listener> LISTENERS = new ArrayList<>();
+
+	public void addListener(Listener newListener) {
+		synchronized (LISTENERS) {
+			LISTENERS.add(newListener);
+		}
+	}
+
+	public void removeListener(Listener listener) {
+		synchronized (LISTENERS) {
+			LISTENERS.remove(listener);
+		}
+	}
+
+	public void notify(Event event) {
+		List<Listener> clonedListeners;
+
+		synchronized (LISTENERS) {
+			clonedListeners = new ArrayList<>(LISTENERS);
+		}
+
+		for (Listener listener : clonedListeners)
+			listener.listen(event);
+	}
+}

src/main/java/org/qortal/event/Listener.java

@@ -0,0 +1,6 @@
+package org.qortal.event;
+
+@FunctionalInterface
+public interface Listener {
+	void listen(Event event);
+}

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

@@ -1,6 +1,8 @@
 package org.qortal.network;
 
 import java.util.Arrays;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -13,7 +15,9 @@ 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.settings.Settings;
 import org.qortal.network.message.ResponseMessage;
+import org.qortal.utils.DaemonThreadFactory;
 import org.qortal.utils.NTP;
 
 import com.google.common.primitives.Bytes;
@@ -27,6 +31,7 @@ public enum Handshake {
 
 		@Override
 		public void action(Peer peer) {
+			/* Never called */
 		}
 	},
 	HELLO(MessageType.HELLO) {
@@ -157,13 +162,20 @@ public enum Handshake {
 			}
 
 			int nonce = responseMessage.getNonce();
-			if (!MemoryPoW.verify2(data, POW_BUFFER_SIZE, POW_DIFFICULTY, nonce)) {
+			int powBufferSize = peer.getPeersVersion() < PEER_VERSION_131 ? POW_BUFFER_SIZE_PRE_131 : POW_BUFFER_SIZE_POST_131;
+			int powDifficulty = peer.getPeersVersion() < PEER_VERSION_131 ? POW_DIFFICULTY_PRE_131 : POW_DIFFICULTY_POST_131;
+			if (!MemoryPoW.verify2(data, powBufferSize, powDifficulty, nonce)) {
 				LOGGER.debug(() -> String.format("Peer %s sent incorrect RESPONSE nonce", peer));
 				return null;
 			}
 
 			peer.setPeersNodeId(Crypto.toNodeAddress(peersPublicKey));
 
+			// For inbound peers, we need to go into interim holding state while we compute RESPONSE
+			if (!peer.isOutbound())
+				return RESPONDING;
+
+			// Handshake completed!
 			return COMPLETED;
 		}
 
@@ -178,28 +190,52 @@ public enum Handshake {
 			final byte[] data = Crypto.digest(Bytes.concat(sharedSecret, peersChallenge));
 
 			// We do this in a new thread as it can take a while...
-			Thread responseThread = new Thread(() -> {
-				Integer nonce = MemoryPoW.compute2(data, POW_BUFFER_SIZE, POW_DIFFICULTY);
+			responseExecutor.execute(() -> {
+				// Are we still connected?
+				if (peer.isStopping())
+					// No point computing for dead peer
+					return;
+
+				int powBufferSize = peer.getPeersVersion() < PEER_VERSION_131 ? POW_BUFFER_SIZE_PRE_131 : POW_BUFFER_SIZE_POST_131;
+				int powDifficulty = peer.getPeersVersion() < PEER_VERSION_131 ? POW_DIFFICULTY_PRE_131 : POW_DIFFICULTY_POST_131;
+				Integer nonce = MemoryPoW.compute2(data, powBufferSize, powDifficulty);
 
 				Message responseMessage = new ResponseMessage(nonce, data);
 				if (!peer.sendMessage(responseMessage))
 					peer.disconnect("failed to send RESPONSE");
-			});
 
-			responseThread.setDaemon(true);
-			responseThread.start();
+				// For inbound peers, we should actually be in RESPONDING state.
+				// So we need to do the extra work to move to COMPLETED state.
+				if (!peer.isOutbound()) {
+					peer.setHandshakeStatus(COMPLETED);
+					Network.getInstance().onHandshakeCompleted(peer);
+				}
+			});
 		}
 	},
-	COMPLETED(null) {
+	// Interim holding state while we compute RESPONSE to send to inbound peer
+	RESPONDING(null) {
 		@Override
 		public Handshake onMessage(Peer peer, Message message) {
-			// Handshake completed
+			// Should never be called
 			return null;
 		}
 
 		@Override
 		public void action(Peer peer) {
-			// Note: this is only called when we've made outbound connection
+			// Should never be called
+		}
+	},
+	COMPLETED(null) {
+		@Override
+		public Handshake onMessage(Peer peer, Message message) {
+			// Should never be called
+			return null;
+		}
+
+		@Override
+		public void action(Peer peer) {
+			// Note: this is only called if we've made outbound connection
 		}
 	};
 
@@ -210,8 +246,16 @@ public enum Handshake {
 
 	private static final Pattern VERSION_PATTERN = Pattern.compile(Controller.VERSION_PREFIX + "(\\d{1,3})\\.(\\d{1,5})\\.(\\d{1,5})");
 
-	private static final int POW_BUFFER_SIZE = 8 * 1024 * 1024; // bytes
-	private static final int POW_DIFFICULTY = 8; // leading zero bits
+	private static final long PEER_VERSION_131 = 0x0100030001L;
+
+	private static final int POW_BUFFER_SIZE_PRE_131 = 8 * 1024 * 1024; // bytes
+	private static final int POW_DIFFICULTY_PRE_131 = 8; // leading zero bits
+	// Can always be made harder in the future...
+	private static final int POW_BUFFER_SIZE_POST_131 = 2 * 1024 * 1024; // bytes
+	private static final int POW_DIFFICULTY_POST_131 = 2; // leading zero bits
+
+
+	private static final ExecutorService responseExecutor = Executors.newFixedThreadPool(Settings.getInstance().getNetworkPoWComputePoolSize(), new DaemonThreadFactory("Network-PoW"));
 
 	private static final byte[] ZERO_CHALLENGE = new byte[ChallengeMessage.CHALLENGE_LENGTH];
 

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

@@ -55,6 +55,7 @@ import org.qortal.utils.ExecuteProduceConsume;
 // import org.qortal.utils.ExecutorDumper;
 import org.qortal.utils.ExecuteProduceConsume.StatsSnapshot;
 import org.qortal.utils.NTP;
+import org.qortal.utils.NamedThreadFactory;
 
 // For managing peers
 public class Network {
@@ -80,16 +81,9 @@ public class Network {
 	private static final byte[] TESTNET_MESSAGE_MAGIC = new byte[] { 0x71, 0x6f, 0x72, 0x54 }; // qorT
 
 	private static final String[] INITIAL_PEERS = new String[] {
-			"node1.qortal.org",
-			"node2.qortal.org",
-			"node3.qortal.org",
-			"node4.qortal.org",
-			"node5.qortal.org",
-			"node6.qortal.org",
-			"node7.qortal.org",
-			"node8.qortal.org",
-			"node9.qortal.org",
-			"node10.qortal.org"
+			"node1.qortal.org", "node2.qortal.org", "node3.qortal.org", "node4.qortal.org", "node5.qortal.org",
+			"node6.qortal.org", "node7.qortal.org", "node8.qortal.org", "node9.qortal.org", "node10.qortal.org",
+			"node.qortal.ru", "node2.qortal.ru", "node3.qortal.ru", "node.qortal.uk"
 	};
 
 	private static final long NETWORK_EPC_KEEPALIVE = 10L; // seconds
@@ -151,7 +145,8 @@ public class Network {
 		ExecutorService networkExecutor = new ThreadPoolExecutor(1,
 				Settings.getInstance().getMaxNetworkThreadPoolSize(),
 				NETWORK_EPC_KEEPALIVE, TimeUnit.SECONDS,
-				new SynchronousQueue<Runnable>());
+				new SynchronousQueue<Runnable>(),
+				new NamedThreadFactory("Network-EPC"));
 		networkEPC = new NetworkProcessor(networkExecutor);
 	}
 
@@ -355,7 +350,7 @@ public class Network {
 
 		private Task maybeProducePeerPingTask(Long now) {
 			// Ask connected peers whether they need a ping
-			for (Peer peer : getConnectedPeers()) {
+			for (Peer peer : getHandshakedPeers()) {
 				Task peerTask = peer.getPingTask(now);
 				if (peerTask != null)
 					return peerTask;
@@ -635,7 +630,7 @@ public class Network {
 
 	/** Called when Peer's thread has setup and is ready to process messages */
 	public void onPeerReady(Peer peer) {
-		this.onMessage(peer, null);
+		onHandshakingMessage(peer, null, Handshake.STARTED);
 	}
 
 	public void onDisconnect(Peer peer) {
@@ -777,7 +772,7 @@ public class Network {
 		opportunisticMergePeers(peer.toString(), peerV2Addresses);
 	}
 
-	private void onHandshakeCompleted(Peer peer) {
+	/*pacakge*/ void onHandshakeCompleted(Peer peer) {
 		LOGGER.debug(String.format("Handshake completed with peer %s", peer));
 
 		// Are we already connected to this peer?

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

@@ -372,9 +372,11 @@ public class Peer {
 					if (message == null && bytesRead == 0 && !wasByteBufferFull) {
 						// No complete message in buffer, no more bytes to read from socket even though there was room to read bytes
 
+						/* DISABLED
 						// If byteBuffer is empty then we can deallocate it, to save memory, albeit costing GC
 						if (this.byteBuffer.remaining() == this.byteBuffer.capacity())
 							this.byteBuffer = null;
+						*/
 
 						return;
 					}

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

@@ -15,6 +15,9 @@ public interface ATRepository {
 	/** Returns where AT with passed address exists in repository */
 	public boolean exists(String atAddress) throws DataException;
 
+	/** Returns AT creator's public key, or null if not found */
+	public byte[] getCreatorPublicKey(String atAddress) throws DataException;
+
 	/** Returns list of executable ATs, empty if none found */
 	public List<ATData> getAllExecutableATs() throws DataException;
 
@@ -54,6 +57,24 @@ public interface ATRepository {
 	 */
 	public ATStateData getLatestATState(String atAddress) throws DataException;
 
+	/**
+	 * Returns final ATStateData for ATs matching codeHash (required)
+	 * and specific data segment value (optional).
+	 * <p>
+	 * If searching for specific data segment value, both <tt>dataByteOffset</tt>
+	 * and <tt>expectedValue</tt> need to be non-null.
+	 * <p>
+	 * Note that <tt>dataByteOffset</tt> starts from 0 and will typically be
+	 * a multiple of <tt>MachineState.VALUE_SIZE</tt>, which is usually 8:
+	 * width of a long.
+	 * <p>
+	 * Although <tt>expectedValue</tt>, if provided, is natively an unsigned long,
+	 * the data segment comparison is done via unsigned hex string.
+	 */
+	public List<ATStateData> getMatchingFinalATStates(byte[] codeHash, Boolean isFinished,
+			Integer dataByteOffset, Long expectedValue, Integer minimumFinalHeight,
+			Integer limit, Integer offset, Boolean reverse) throws DataException;
+
 	/**
 	 * Returns all ATStateData for a given block height.
 	 * <p>
@@ -88,4 +109,28 @@ public interface ATRepository {
 	/** Delete state data for all ATs at this height */
 	public void deleteATStates(int height) throws DataException;
 
+	// Finding transactions for ATs to process
+
+	static class NextTransactionInfo {
+		public final int height;
+		public final int sequence;
+		public final byte[] signature;
+
+		public NextTransactionInfo(int height, int sequence, byte[] signature) {
+			this.height = height;
+			this.sequence = sequence;
+			this.signature = signature;
+		}
+	}
+
+	/**
+	 * Find next transaction for AT to process.
+	 * <p>
+	 * @param recipient AT address
+	 * @param height starting height
+	 * @param sequence starting sequence
+	 * @return next transaction info, or null if none found
+	 */
+	public NextTransactionInfo findNextTransaction(String recipient, int height, int sequence) throws DataException;
+
 }

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

@@ -169,8 +169,8 @@ public interface AccountRepository {
 
 	public void save(MintingAccountData mintingAccountData) throws DataException;
 
-	/** Delete minting account info, used by BlockMinter, from repository using passed private key. */
-	public int delete(byte[] mintingAccountPrivateKey) throws DataException;
+	/** Delete minting account info, used by BlockMinter, from repository using passed public or private key. */
+	public int delete(byte[] mintingAccountKey) throws DataException;
 
 	// Managing QORT from legacy QORA
 

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

@@ -2,6 +2,7 @@ package org.qortal.repository;
 
 import java.util.List;
 
+import org.qortal.api.model.BlockInfo;
 import org.qortal.api.model.BlockSignerSummary;
 import org.qortal.data.block.BlockData;
 import org.qortal.data.block.BlockSummaryData;
@@ -60,6 +61,15 @@ public interface BlockRepository {
 	 */
 	public int getHeightFromTimestamp(long timestamp) throws DataException;
 
+	/**
+	 * Returns block timestamp for a given height.
+	 *
+	 * @param height
+	 * @return timestamp, or 0 if height is out of bounds.
+	 * @throws DataException
+	 */
+	public long getTimestampFromHeight(int height) throws DataException;
+
 	/**
 	 * Return highest block height from repository.
 	 * 
@@ -128,6 +138,11 @@ public interface BlockRepository {
 	 */
 	public List<BlockSummaryData> getBlockSummaries(int firstBlockHeight, int lastBlockHeight) throws DataException;
 
+	/**
+	 * Returns block infos for the passed height range, for API use.
+	 */
+	public List<BlockInfo> getBlockInfos(Integer startHeight, Integer endHeight, Integer count) throws DataException;
+
 	/**
 	 * Trim online accounts signatures from blocks older than passed timestamp.
 	 * 
@@ -137,11 +152,12 @@ public interface BlockRepository {
 	public int trimOldOnlineAccountsSignatures(long timestamp) throws DataException;
 
 	/**
-	 * Returns first (lowest height) block that doesn't link back to genesis block.
+	 * Returns first (lowest height) block that doesn't link back to specified block.
 	 * 
+	 * @param startHeight height of specified block
 	 * @throws DataException
 	 */
-	public BlockData getDetachedBlockSignature() throws DataException;
+	public BlockData getDetachedBlockSignature(int startHeight) throws DataException;
 
 	/**
 	 * Saves block into repository.

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

@@ -0,0 +1,18 @@
+package org.qortal.repository;
+
+import java.util.List;
+
+import org.qortal.data.crosschain.TradeBotData;
+
+public interface CrossChainRepository {
+
+	public TradeBotData getTradeBotData(byte[] tradePrivateKey) throws DataException;
+
+	public List<TradeBotData> getAllTradeBotData() throws DataException;
+
+	public void save(TradeBotData tradeBotData) throws DataException;
+
+	/** Delete trade-bot states using passed private key. */
+	public int delete(byte[] tradePrivateKey) throws DataException;
+
+}

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

@@ -14,6 +14,8 @@ public interface Repository extends AutoCloseable {
 
 	public ChatRepository getChatRepository();
 
+	public CrossChainRepository getCrossChainRepository();
+
 	public GroupRepository getGroupRepository();
 
 	public NameRepository getNameRepository();

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

@@ -6,6 +6,7 @@ import java.util.Map;
 import org.qortal.api.resource.TransactionsResource.ConfirmationStatus;
 import org.qortal.data.group.GroupApprovalData;
 import org.qortal.data.transaction.GroupApprovalTransactionData;
+import org.qortal.data.transaction.MessageTransactionData;
 import org.qortal.data.transaction.TransactionData;
 import org.qortal.data.transaction.TransferAssetTransactionData;
 import org.qortal.transaction.Transaction.TransactionType;
@@ -107,6 +108,18 @@ public interface TransactionRepository {
 	 */
 	public byte[] getLatestAutoUpdateTransaction(TransactionType txType, int txGroupId, Integer service) throws DataException;
 
+	/**
+	 * Returns list of MESSAGE transaction data matching recipient.
+	 * @param recipient
+	 * @param limit
+	 * @param offset
+	 * @param reverse
+	 * @return
+	 * @throws DataException
+	 */
+	public List<MessageTransactionData> getMessagesByRecipient(String recipient,
+			Integer limit, Integer offset, Boolean reverse) throws DataException;
+
 	/**
 	 * Returns list of transactions relating to specific asset ID.
 	 * 

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

@@ -68,6 +68,20 @@ public class HSQLDBATRepository implements ATRepository {
 		}
 	}
 
+	@Override
+	public byte[] getCreatorPublicKey(String atAddress) throws DataException {
+		String sql = "SELECT creator FROM ATs WHERE AT_address = ?";
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql, atAddress)) {
+			if (resultSet == null)
+				return null;
+
+			return resultSet.getBytes(1);
+		} catch (SQLException e) {
+			throw new DataException("Unable to fetch AT creator's public key from repository", e);
+		}
+	}
+
 	@Override
 	public List<ATData> getAllExecutableATs() throws DataException {
 		String sql = "SELECT AT_address, creator, created_when, version, asset_id, code_bytes, code_hash, "
@@ -254,7 +268,8 @@ public class HSQLDBATRepository implements ATRepository {
 				+ "FROM ATStates "
 				+ "WHERE AT_address = ? "
 				+ "ORDER BY height DESC "
-				+ "LIMIT 1";
+				+ "LIMIT 1 "
+				+ "USING INDEX";
 
 		try (ResultSet resultSet = this.repository.checkedExecute(sql, atAddress)) {
 			if (resultSet == null)
@@ -273,6 +288,79 @@ public class HSQLDBATRepository implements ATRepository {
 		}
 	}
 
+	@Override
+	public List<ATStateData> getMatchingFinalATStates(byte[] codeHash, Boolean isFinished,
+			Integer dataByteOffset, Long expectedValue, Integer minimumFinalHeight,
+			Integer limit, Integer offset, Boolean reverse) throws DataException {
+		StringBuilder sql = new StringBuilder(1024);
+		sql.append("SELECT AT_address, height, created_when, state_data, state_hash, fees, is_initial "
+				+ "FROM ATs "
+				+ "CROSS JOIN LATERAL("
+					+ "SELECT height, created_when, state_data, state_hash, fees, is_initial "
+					+ "FROM ATStates "
+					+ "WHERE ATStates.AT_address = ATs.AT_address "
+					+ "ORDER BY height DESC "
+					+ "LIMIT 1 "
+					+ "USING INDEX"
+				+ ") AS FinalATStates "
+				+ "WHERE code_hash = ? ");
+
+		List<Object> bindParams = new ArrayList<>();
+		bindParams.add(codeHash);
+
+		if (isFinished != null) {
+			sql.append("AND is_finished = ?");
+			bindParams.add(isFinished);
+		}
+
+		if (dataByteOffset != null && expectedValue != null) {
+			sql.append("AND RAWTOHEX(SUBSTRING(state_data FROM ? FOR 8)) = ? ");
+
+			// We convert our long to hex Java-side to control endian
+			String expectedHexValue = String.format("%016x", expectedValue); // left-zero-padding and conversion
+
+			// SQL binary data offsets start at 1
+			bindParams.add(dataByteOffset + 1);
+			bindParams.add(expectedHexValue);
+		}
+
+		if (minimumFinalHeight != null) {
+			sql.append("AND height >= ");
+			sql.append(minimumFinalHeight);
+		}
+
+		sql.append(" ORDER BY height ");
+		if (reverse != null && reverse)
+			sql.append("DESC");
+
+		HSQLDBRepository.limitOffsetSql(sql, limit, offset);
+
+		List<ATStateData> atStates = new ArrayList<>();
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql.toString(), bindParams.toArray())) {
+			if (resultSet == null)
+				return atStates;
+
+			do {
+				String atAddress = resultSet.getString(1);
+				int height = resultSet.getInt(2);
+				long created = resultSet.getLong(3);
+				byte[] stateData = resultSet.getBytes(4); // Actually BLOB
+				byte[] stateHash = resultSet.getBytes(5);
+				long fees = resultSet.getLong(6);
+				boolean isInitial = resultSet.getBoolean(7);
+
+				ATStateData atStateData = new ATStateData(atAddress, height, created, stateData, stateHash, fees, isInitial);
+
+				atStates.add(atStateData);
+			} while (resultSet.next());
+
+			return atStates;
+		} catch (SQLException e) {
+			throw new DataException("Unable to fetch matching AT states from repository", e);
+		}
+	}
+
 	@Override
 	public List<ATStateData> getBlockATStatesAtHeight(int height) throws DataException {
 		String sql = "SELECT AT_address, state_hash, fees, is_initial "
@@ -341,4 +429,40 @@ public class HSQLDBATRepository implements ATRepository {
 		}
 	}
 
+	// Finding transactions for ATs to process
+
+	public NextTransactionInfo findNextTransaction(String recipient, int height, int sequence) throws DataException {
+		// We only need to search for a subset of transaction types: MESSAGE, PAYMENT or AT
+
+		String sql = "SELECT height, sequence, Transactions.signature "
+				+ "FROM ("
+					+ "SELECT signature FROM PaymentTransactions WHERE recipient = ? "
+					+ "UNION "
+					+ "SELECT signature FROM MessageTransactions WHERE recipient = ? "
+					+ "UNION "
+					+ "SELECT signature FROM ATTransactions WHERE recipient = ?"
+				+ ") AS Transactions "
+				+ "JOIN BlockTransactions ON BlockTransactions.transaction_signature = Transactions.signature "
+				+ "JOIN Blocks ON Blocks.signature = BlockTransactions.block_signature "
+				+ "WHERE (height > ? OR (height = ? AND sequence > ?)) "
+				+ "ORDER BY height ASC, sequence ASC "
+				+ "LIMIT 1";
+
+		Object[] bindParams = new Object[] { recipient, recipient, recipient, height, height, sequence };
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql, bindParams)) {
+			if (resultSet == null)
+				return null;
+
+			int nextHeight = resultSet.getInt(1);
+			int nextSequence = resultSet.getInt(2);
+			byte[] nextSignature = resultSet.getBytes(3);
+
+			return new NextTransactionInfo(nextHeight, nextSequence, nextSignature);
+		} catch (SQLException e) {
+			throw new DataException("Unable to find next transaction to AT from repository", e);
+		}
+
+	}
+
 }

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

@@ -774,9 +774,9 @@ public class HSQLDBAccountRepository implements AccountRepository {
 	}
 
 	@Override
-	public int delete(byte[] minterPrivateKey) throws DataException {
+	public int delete(byte[] minterKey) throws DataException {
 		try {
-			return this.repository.delete("MintingAccounts", "minter_private_key = ?", minterPrivateKey);
+			return this.repository.delete("MintingAccounts", "minter_private_key = ? OR minter_public_key = ?", minterKey, minterKey);
 		} catch (SQLException e) {
 			throw new DataException("Unable to delete minting account from repository", e);
 		}

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

@@ -6,6 +6,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
+import org.qortal.api.model.BlockInfo;
 import org.qortal.api.model.BlockSignerSummary;
 import org.qortal.data.block.BlockData;
 import org.qortal.data.block.BlockSummaryData;
@@ -131,6 +132,20 @@ public class HSQLDBBlockRepository implements BlockRepository {
 		}
 	}
 
+	@Override
+	public long getTimestampFromHeight(int height) throws DataException {
+		String sql = "SELECT minted_when FROM Blocks WHERE height = ?";
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql, height)) {
+			if (resultSet == null)
+				return 0;
+
+			return resultSet.getLong(1);
+		} catch (SQLException e) {
+			throw new DataException("Error obtaining block timestamp by height from repository", e);
+		}
+	}
+
 	@Override
 	public int getBlockchainHeight() throws DataException {
 		String sql = "SELECT height FROM Blocks ORDER BY height DESC LIMIT 1";
@@ -360,6 +375,90 @@ public class HSQLDBBlockRepository implements BlockRepository {
 		}
 	}
 
+	@Override
+	public List<BlockInfo> getBlockInfos(Integer startHeight, Integer endHeight, Integer count) throws DataException {
+		StringBuilder sql = new StringBuilder(512);
+		sql.append("SELECT signature, height, minted_when, transaction_count, RewardShares.minter ");
+
+		/*
+		 * start	end		count		result
+		 * 10		40		null		blocks 10 to 39 (excludes end block, ignore count)
+		 * 
+		 * null		null	null		blocks 1 to 50 (assume count=50, maybe start=1)
+		 * 30		null	null		blocks 30 to 79 (assume count=50)
+		 * 30		null	10			blocks 30 to 39
+		 * 
+		 * null		null	50			last 50 blocks? so if max(blocks.height) is 200, then blocks 151 to 200
+		 * null		200		null		blocks 150 to 199 (excludes end block, assume count=50)
+		 * null		200		10			blocks 190 to 199 (excludes end block)
+		 */
+
+		if (startHeight != null && endHeight != null) {
+			sql.append("FROM Blocks ");
+			sql.append("JOIN RewardShares ON RewardShares.reward_share_public_key = Blocks.minter ");
+			sql.append("WHERE height BETWEEN ");
+			sql.append(startHeight);
+			sql.append(" AND ");
+			sql.append(endHeight - 1);
+		} else if (endHeight != null || (startHeight == null && count != null)) {
+			// we are going to return blocks from the end of the chain
+			if (count == null)
+				count = 50;
+
+			if (endHeight == null) {
+				sql.append("FROM (SELECT height FROM Blocks ORDER BY height DESC LIMIT 1) AS MaxHeights (max_height) ");
+				sql.append("JOIN Blocks ON height BETWEEN (max_height - ");
+				sql.append(count);
+				sql.append(" + 1) AND max_height ");
+				sql.append("JOIN RewardShares ON RewardShares.reward_share_public_key = Blocks.minter");
+			} else {
+				sql.append("FROM Blocks ");
+				sql.append("JOIN RewardShares ON RewardShares.reward_share_public_key = Blocks.minter ");
+				sql.append("WHERE height BETWEEN ");
+				sql.append(endHeight - count);
+				sql.append(" AND ");
+				sql.append(endHeight - 1);
+			}
+
+		} else {
+			// we are going to return blocks from the start of the chain
+			if (startHeight == null)
+				startHeight = 1;
+
+			if (count == null)
+				count = 50;
+
+			sql.append("FROM Blocks ");
+			sql.append("JOIN RewardShares ON RewardShares.reward_share_public_key = Blocks.minter ");
+			sql.append("WHERE height BETWEEN ");
+			sql.append(startHeight);
+			sql.append(" AND ");
+			sql.append(startHeight + count - 1);
+		}
+
+		List<BlockInfo> blockInfos = new ArrayList<>();
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql.toString())) {
+			if (resultSet == null)
+				return blockInfos;
+
+			do {
+				byte[] signature = resultSet.getBytes(1);
+				int height = resultSet.getInt(2);
+				long timestamp = resultSet.getLong(3);
+				int transactionCount = resultSet.getInt(4);
+				String minterAddress = resultSet.getString(5);
+
+				BlockInfo blockInfo = new BlockInfo(signature, height, timestamp, transactionCount, minterAddress);
+				blockInfos.add(blockInfo);
+			} while (resultSet.next());
+
+			return blockInfos;
+		} catch (SQLException e) {
+			throw new DataException("Unable to fetch height-ranged block infos from repository", e);
+		}
+	}
+
 	@Override
 	public int trimOldOnlineAccountsSignatures(long timestamp) throws DataException {
 		String sql = "UPDATE Blocks set online_accounts_signatures = NULL WHERE minted_when < ? AND online_accounts_signatures IS NOT NULL";
@@ -372,14 +471,14 @@ public class HSQLDBBlockRepository implements BlockRepository {
 	}
 
 	@Override
-	public BlockData getDetachedBlockSignature() throws DataException {
+	public BlockData getDetachedBlockSignature(int startHeight) throws DataException {
 		String sql = "SELECT " + BLOCK_DB_COLUMNS + " FROM Blocks "
 				+ "LEFT OUTER JOIN Blocks AS ParentBlocks "
 				+ "ON ParentBlocks.signature = Blocks.reference "
-				+ "WHERE ParentBlocks.signature IS NULL AND Blocks.height > 1 "
+				+ "WHERE ParentBlocks.signature IS NULL AND Blocks.height > ? "
 				+ "ORDER BY Blocks.height ASC LIMIT 1";
 
-		try (ResultSet resultSet = this.repository.checkedExecute(sql)) {
+		try (ResultSet resultSet = this.repository.checkedExecute(sql, startHeight)) {
 			return getBlockFromResultSet(resultSet);
 		} catch (SQLException e) {
 			throw new DataException("Error fetching block by signature from repository", e);

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

@@ -0,0 +1,165 @@
+package org.qortal.repository.hsqldb;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.qortal.data.crosschain.TradeBotData;
+import org.qortal.repository.CrossChainRepository;
+import org.qortal.repository.DataException;
+
+public class HSQLDBCrossChainRepository implements CrossChainRepository {
+
+	protected HSQLDBRepository repository;
+
+	public HSQLDBCrossChainRepository(HSQLDBRepository repository) {
+		this.repository = repository;
+	}
+
+	@Override
+	public TradeBotData getTradeBotData(byte[] tradePrivateKey) throws DataException {
+		String sql = "SELECT trade_state, creator_address, at_address, "
+				+ "updated_when, qort_amount, "
+				+ "trade_native_public_key, trade_native_public_key_hash, "
+				+ "trade_native_address, secret, hash_of_secret, "
+				+ "trade_foreign_public_key, trade_foreign_public_key_hash, "
+				+ "bitcoin_amount, xprv58, last_transaction_signature, locktime_a, receiving_account_info "
+				+ "FROM TradeBotStates "
+				+ "WHERE trade_private_key = ?";
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql, tradePrivateKey)) {
+			if (resultSet == null)
+				return null;
+
+			int tradeStateValue = resultSet.getInt(1);
+			TradeBotData.State tradeState = TradeBotData.State.valueOf(tradeStateValue);
+			if (tradeState == null)
+				throw new DataException("Illegal trade-bot trade-state fetched from repository");
+
+			String creatorAddress = resultSet.getString(2);
+			String atAddress = resultSet.getString(3);
+			long timestamp = resultSet.getLong(4);
+			long qortAmount = resultSet.getLong(5);
+			byte[] tradeNativePublicKey = resultSet.getBytes(6);
+			byte[] tradeNativePublicKeyHash = resultSet.getBytes(7);
+			String tradeNativeAddress = resultSet.getString(8);
+			byte[] secret = resultSet.getBytes(9);
+			byte[] hashOfSecret = resultSet.getBytes(10);
+			byte[] tradeForeignPublicKey = resultSet.getBytes(11);
+			byte[] tradeForeignPublicKeyHash = resultSet.getBytes(12);
+			long bitcoinAmount = resultSet.getLong(13);
+			String xprv58 = resultSet.getString(14);
+			byte[] lastTransactionSignature = resultSet.getBytes(15);
+			Integer lockTimeA = resultSet.getInt(16);
+			if (lockTimeA == 0 && resultSet.wasNull())
+				lockTimeA = null;
+			byte[] receivingAccountInfo = resultSet.getBytes(17);
+
+			return new TradeBotData(tradePrivateKey, tradeState,
+					creatorAddress, atAddress, timestamp, qortAmount,
+					tradeNativePublicKey, tradeNativePublicKeyHash, tradeNativeAddress,
+					secret, hashOfSecret,
+					tradeForeignPublicKey, tradeForeignPublicKeyHash,
+					bitcoinAmount, xprv58, lastTransactionSignature, lockTimeA, receivingAccountInfo);
+		} catch (SQLException e) {
+			throw new DataException("Unable to fetch trade-bot trading state from repository", e);
+		}
+	}
+
+	@Override
+	public List<TradeBotData> getAllTradeBotData() throws DataException {
+		String sql = "SELECT trade_private_key, trade_state, creator_address, at_address, "
+				+ "updated_when, qort_amount, "
+				+ "trade_native_public_key, trade_native_public_key_hash, "
+				+ "trade_native_address, secret, hash_of_secret, "
+				+ "trade_foreign_public_key, trade_foreign_public_key_hash, "
+				+ "bitcoin_amount, xprv58, last_transaction_signature, locktime_a, receiving_account_info "
+				+ "FROM TradeBotStates";
+
+		List<TradeBotData> allTradeBotData = new ArrayList<>();
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql)) {
+			if (resultSet == null)
+				return allTradeBotData;
+
+			do {
+				byte[] tradePrivateKey = resultSet.getBytes(1);
+				int tradeStateValue = resultSet.getInt(2);
+				TradeBotData.State tradeState = TradeBotData.State.valueOf(tradeStateValue);
+				if (tradeState == null)
+					throw new DataException("Illegal trade-bot trade-state fetched from repository");
+
+				String creatorAddress = resultSet.getString(3);
+				String atAddress = resultSet.getString(4);
+				long timestamp = resultSet.getLong(5);
+				long qortAmount = resultSet.getLong(6);
+				byte[] tradeNativePublicKey = resultSet.getBytes(7);
+				byte[] tradeNativePublicKeyHash = resultSet.getBytes(8);
+				String tradeNativeAddress = resultSet.getString(9);
+				byte[] secret = resultSet.getBytes(10);
+				byte[] hashOfSecret = resultSet.getBytes(11);
+				byte[] tradeForeignPublicKey = resultSet.getBytes(12);
+				byte[] tradeForeignPublicKeyHash = resultSet.getBytes(13);
+				long bitcoinAmount = resultSet.getLong(14);
+				String xprv58 = resultSet.getString(15);
+				byte[] lastTransactionSignature = resultSet.getBytes(16);
+				Integer lockTimeA = resultSet.getInt(17);
+				if (lockTimeA == 0 && resultSet.wasNull())
+					lockTimeA = null;
+				byte[] receivingAccountInfo = resultSet.getBytes(18);
+
+				TradeBotData tradeBotData = new TradeBotData(tradePrivateKey, tradeState,
+						creatorAddress, atAddress, timestamp, qortAmount,
+						tradeNativePublicKey, tradeNativePublicKeyHash, tradeNativeAddress,
+						secret, hashOfSecret,
+						tradeForeignPublicKey, tradeForeignPublicKeyHash,
+						bitcoinAmount, xprv58, lastTransactionSignature, lockTimeA, receivingAccountInfo);
+				allTradeBotData.add(tradeBotData);
+			} while (resultSet.next());
+
+			return allTradeBotData;
+		} catch (SQLException e) {
+			throw new DataException("Unable to fetch trade-bot trading states from repository", e);
+		}
+	}
+
+	@Override
+	public void save(TradeBotData tradeBotData) throws DataException {
+		HSQLDBSaver saveHelper = new HSQLDBSaver("TradeBotStates");
+
+		saveHelper.bind("trade_private_key", tradeBotData.getTradePrivateKey())
+				.bind("trade_state", tradeBotData.getState().value)
+				.bind("creator_address", tradeBotData.getCreatorAddress())
+				.bind("at_address", tradeBotData.getAtAddress())
+				.bind("updated_when", tradeBotData.getTimestamp())
+				.bind("qort_amount", tradeBotData.getQortAmount())
+				.bind("trade_native_public_key", tradeBotData.getTradeNativePublicKey())
+				.bind("trade_native_public_key_hash", tradeBotData.getTradeNativePublicKeyHash())
+				.bind("trade_native_address", tradeBotData.getTradeNativeAddress())
+				.bind("secret", tradeBotData.getSecret()).bind("hash_of_secret", tradeBotData.getHashOfSecret())
+				.bind("trade_foreign_public_key", tradeBotData.getTradeForeignPublicKey())
+				.bind("trade_foreign_public_key_hash", tradeBotData.getTradeForeignPublicKeyHash())
+				.bind("bitcoin_amount", tradeBotData.getBitcoinAmount())
+				.bind("xprv58", tradeBotData.getXprv58())
+				.bind("last_transaction_signature", tradeBotData.getLastTransactionSignature())
+				.bind("locktime_a", tradeBotData.getLockTimeA())
+				.bind("receiving_account_info", tradeBotData.getReceivingAccountInfo());
+
+		try {
+			saveHelper.execute(this.repository);
+		} catch (SQLException e) {
+			throw new DataException("Unable to save trade bot data into repository", e);
+		}
+	}
+
+	@Override
+	public int delete(byte[] tradePrivateKey) throws DataException {
+		try {
+			return this.repository.delete("TradeBotStates", "trade_private_key = ?", tradePrivateKey);
+		} catch (SQLException e) {
+			throw new DataException("Unable to delete trade-bot states from repository", e);
+		}
+	}
+
+}

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

@@ -95,7 +95,6 @@ public class HSQLDBDatabaseUpdates {
 					stmt.execute("CREATE COLLATION SQL_TEXT_NO_PAD FOR SQL_TEXT FROM SQL_TEXT NO PAD");
 
 					stmt.execute("SET FILES SPACE TRUE"); // Enable per-table block space within .data file, useful for CACHED table types
-					stmt.execute("SET FILES LOB SCALE 1"); // LOB granularity is 1KB
 					// Slow down log fsync() calls from every 500ms to reduce I/O load
 					stmt.execute("SET FILES WRITE DELAY 5"); // only fsync() every 5 seconds
 
@@ -103,15 +102,15 @@ public class HSQLDBDatabaseUpdates {
 					stmt.execute("INSERT INTO DatabaseInfo VALUES ( 0 )");
 
 					stmt.execute("CREATE TYPE ArbitraryData AS VARBINARY(256)");
-					stmt.execute("CREATE TYPE AssetData AS CLOB(400K)");
+					stmt.execute("CREATE TYPE AssetData AS VARCHAR(400K)");
 					stmt.execute("CREATE TYPE AssetID AS BIGINT");
 					stmt.execute("CREATE TYPE AssetName AS VARCHAR(34) COLLATE SQL_TEXT_NO_PAD");
 					stmt.execute("CREATE TYPE AssetOrderID AS VARBINARY(64)");
-					stmt.execute("CREATE TYPE ATCode AS BLOB(64K)"); // 16bit * 1
-					stmt.execute("CREATE TYPE ATCreationBytes AS BLOB(576K)"); // 16bit * 1 + 16bit * 8
+					stmt.execute("CREATE TYPE ATCode AS VARBINARY(1024)"); // was: 16bit * 1
+					stmt.execute("CREATE TYPE ATCreationBytes AS VARBINARY(4096)"); // was: 16bit * 1 + 16bit * 8
 					stmt.execute("CREATE TYPE ATMessage AS VARBINARY(32)");
 					stmt.execute("CREATE TYPE ATName AS VARCHAR(32) COLLATE SQL_TEXT_UCC_NO_PAD");
-					stmt.execute("CREATE TYPE ATState AS BLOB(1M)"); // 16bit * 8 + 16bit * 4 + 16bit * 4
+					stmt.execute("CREATE TYPE ATState AS VARBINARY(1024)"); // was: 16bit * 8 + 16bit * 4 + 16bit * 4
 					stmt.execute("CREATE TYPE ATTags AS VARCHAR(80) COLLATE SQL_TEXT_UCC_NO_PAD");
 					stmt.execute("CREATE TYPE ATType AS VARCHAR(32) COLLATE SQL_TEXT_UCC_NO_PAD");
 					stmt.execute("CREATE TYPE ATStateHash as VARBINARY(32)");
@@ -142,7 +141,7 @@ public class HSQLDBDatabaseUpdates {
 							+ "transaction_count INTEGER NOT NULL, total_fees QortalAmount NOT NULL, transactions_signature Signature NOT NULL, "
 							+ "height INTEGER NOT NULL, minted_when EpochMillis NOT NULL, "
 							+ "minter QortalPublicKey NOT NULL, minter_signature Signature NOT NULL, AT_count INTEGER NOT NULL, AT_fees QortalAmount NOT NULL, "
-							+ "online_accounts BLOB(1M), online_accounts_count INTEGER NOT NULL, online_accounts_timestamp EpochMillis, online_accounts_signatures BLOB(1M), "
+							+ "online_accounts VARBINARY(1204), online_accounts_count INTEGER NOT NULL, online_accounts_timestamp EpochMillis, online_accounts_signatures VARBINARY(1M), "
 							+ "PRIMARY KEY (signature))");
 					// For finding blocks by height.
 					stmt.execute("CREATE INDEX BlockHeightIndex ON Blocks (height)");
@@ -618,6 +617,39 @@ public class HSQLDBDatabaseUpdates {
 					stmt.execute("CREATE TABLE PublicizeTransactions (signature Signature, nonce INT NOT NULL, " + TRANSACTION_KEYS + ")");
 					break;
 
+				case 20:
+					// Trade bot
+					stmt.execute("CREATE TABLE TradeBotStates (trade_private_key QortalKeySeed NOT NULL, trade_state TINYINT NOT NULL, "
+							+ "creator_address QortalAddress NOT NULL, at_address QortalAddress, updated_when BIGINT NOT NULL, qort_amount QortalAmount NOT NULL, "
+							+ "trade_native_public_key QortalPublicKey NOT NULL, trade_native_public_key_hash VARBINARY(32) NOT NULL, "
+							+ "trade_native_address QortalAddress NOT NULL, secret VARBINARY(32) NOT NULL, hash_of_secret VARBINARY(32) NOT NULL, "
+							+ "trade_foreign_public_key VARBINARY(33) NOT NULL, trade_foreign_public_key_hash VARBINARY(32) NOT NULL, "
+							+ "bitcoin_amount BIGINT NOT NULL, xprv58 VARCHAR(200), last_transaction_signature Signature, locktime_a BIGINT, "
+							+ "receiving_account_info VARBINARY(32) NOT NULL, PRIMARY KEY (trade_private_key))");
+					break;
+
+				case 21:
+					// AT functionality index
+					stmt.execute("CREATE INDEX IF NOT EXISTS ATCodeHashIndex ON ATs (code_hash, is_finished)");
+					break;
+
+				case 22:
+					// LOB downsizing
+					stmt.execute("ALTER TABLE Blocks ALTER COLUMN online_accounts VARBINARY(1024)");
+					stmt.execute("CHECKPOINT");
+					stmt.execute("ALTER TABLE Blocks ALTER COLUMN online_accounts_signatures VARBINARY(1048576)");
+					stmt.execute("CHECKPOINT");
+
+					stmt.execute("ALTER TABLE DeployATTransactions ALTER COLUMN creation_bytes VARBINARY(4096)");
+					stmt.execute("CHECKPOINT");
+
+					stmt.execute("ALTER TABLE ATs ALTER COLUMN code_bytes VARBINARY(1024)");
+					stmt.execute("CHECKPOINT");
+
+					stmt.execute("ALTER TABLE ATStates ALTER COLUMN state_data VARBINARY(1024)");
+					stmt.execute("CHECKPOINT");
+					break;
+
 				default:
 					// nothing to do
 					return false;

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

@@ -32,6 +32,7 @@ import org.qortal.repository.ArbitraryRepository;
 import org.qortal.repository.AssetRepository;
 import org.qortal.repository.BlockRepository;
 import org.qortal.repository.ChatRepository;
+import org.qortal.repository.CrossChainRepository;
 import org.qortal.repository.DataException;
 import org.qortal.repository.GroupRepository;
 import org.qortal.repository.NameRepository;
@@ -115,6 +116,11 @@ public class HSQLDBRepository implements Repository {
 		return new HSQLDBChatRepository(this);
 	}
 
+	@Override
+	public CrossChainRepository getCrossChainRepository() {
+		return new HSQLDBCrossChainRepository(this);
+	}
+
 	@Override
 	public GroupRepository getGroupRepository() {
 		return new HSQLDBGroupRepository(this);

src/main/java/org/qortal/repository/hsqldb/transaction/HSQLDBTransactionRepository.java

@@ -19,6 +19,7 @@ import org.qortal.data.PaymentData;
 import org.qortal.data.group.GroupApprovalData;
 import org.qortal.data.transaction.BaseTransactionData;
 import org.qortal.data.transaction.GroupApprovalTransactionData;
+import org.qortal.data.transaction.MessageTransactionData;
 import org.qortal.data.transaction.TransactionData;
 import org.qortal.data.transaction.TransferAssetTransactionData;
 import org.qortal.repository.DataException;
@@ -630,6 +631,43 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 		}
 	}
 
+	@Override
+	public List<MessageTransactionData> getMessagesByRecipient(String recipient,
+			Integer limit, Integer offset, Boolean reverse) throws DataException {
+		StringBuilder sql = new StringBuilder(1024);
+		sql.append("SELECT signature from MessageTransactions "
+				+ "JOIN Transactions USING (signature) "
+				+ "JOIN BlockTransactions ON transaction_signature = signature "
+				+ "WHERE recipient = ?");
+
+		sql.append("ORDER BY Transactions.created_when");
+		sql.append((reverse == null || !reverse) ? " ASC" : " DESC");
+
+		HSQLDBRepository.limitOffsetSql(sql, limit, offset);
+
+		List<MessageTransactionData> messageTransactionsData = new ArrayList<>();
+
+		try (ResultSet resultSet = this.repository.checkedExecute(sql.toString(), recipient)) {
+			if (resultSet == null)
+				return messageTransactionsData;
+
+			do {
+				byte[] signature = resultSet.getBytes(1);
+
+				TransactionData transactionData = this.fromSignature(signature);
+				if (transactionData == null || transactionData.getType() != TransactionType.MESSAGE)
+					return null;
+
+				messageTransactionsData.add((MessageTransactionData) transactionData);
+			} while (resultSet.next());
+
+			return messageTransactionsData;
+		} catch (SQLException e) {
+			throw new DataException("Unable to fetch trade-bot messages from repository", e);
+		}
+	}
+
+
 	@Override
 	public List<TransactionData> getAssetTransactions(long assetId, ConfirmationStatus confirmationStatus, Integer limit, Integer offset, Boolean reverse)
 			throws DataException {

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

@@ -47,7 +47,7 @@ public class Settings {
 	// UI servers
 	private int uiPort = 12388;
 	private String[] uiLocalServers = new String[] {
-		"localhost", "172.24.1.1", "qor.tal"
+		"localhost", "127.0.0.1", "172.24.1.1", "qor.tal"
 	};
 	private String[] uiRemoteServers = new String[] {
 		"node1.qortal.org", "node2.qortal.org", "node3.qortal.org", "node4.qortal.org", "node5.qortal.org",
@@ -92,6 +92,8 @@ public class Settings {
 	private int maxPeers = 32;
 	/** Maximum number of threads for network engine. */
 	private int maxNetworkThreadPoolSize = 20;
+	/** Maximum number of threads for network proof-of-work compute, used during handshaking. */
+	private int networkPoWComputePoolSize = 2;
 
 	// Which blockchains this node is running
 	private String blockchainConfig = null; // use default from resources
@@ -105,8 +107,8 @@ public class Settings {
 
 	// Auto-update sources
 	private String[] autoUpdateRepos = new String[] {
-		"https://github.com/QORT/qortal/raw/%s/qortal.update",
-		"https://raw.githubusercontent.com@151.101.16.133/QORT/qortal/%s/qortal.update"
+		"https://github.com/Qortal/qortal/raw/%s/qortal.update",
+		"https://raw.githubusercontent.com@151.101.16.133/Qortal/qortal/%s/qortal.update"
 	};
 
 	/** Array of NTP server hostnames. */
@@ -353,6 +355,10 @@ public class Settings {
 		return this.maxNetworkThreadPoolSize;
 	}
 
+	public int getNetworkPoWComputePoolSize() {
+		return this.networkPoWComputePoolSize;
+	}
+
 	public String getBlockchainConfig() {
 		return this.blockchainConfig;
 	}

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

@@ -26,45 +26,47 @@ import com.google.common.base.Utf8;
 public class DeployAtTransaction extends Transaction {
 
 	// Properties
-	private DeployAtTransactionData deployATTransactionData;
+	private DeployAtTransactionData deployAtTransactionData;
 
 	// Other useful constants
 	public static final int MAX_NAME_SIZE = 200;
 	public static final int MAX_DESCRIPTION_SIZE = 2000;
 	public static final int MAX_AT_TYPE_SIZE = 200;
 	public static final int MAX_TAGS_SIZE = 200;
-	public static final int MAX_CREATION_BYTES_SIZE = 100_000;
+	public static final int MAX_CREATION_BYTES_SIZE = 4096;
+	public static final int MAX_CODE_BYTES_LENGTH = 1024;
+	public static final int MAX_AT_STATE_LENGTH = 1024;
 
 	// Constructors
 
 	public DeployAtTransaction(Repository repository, TransactionData transactionData) {
 		super(repository, transactionData);
 
-		this.deployATTransactionData = (DeployAtTransactionData) this.transactionData;
+		this.deployAtTransactionData = (DeployAtTransactionData) this.transactionData;
 	}
 
 	// More information
 
 	@Override
 	public List<String> getRecipientAddresses() throws DataException {
-		return Collections.singletonList(this.deployATTransactionData.getAtAddress());
+		return Collections.singletonList(this.deployAtTransactionData.getAtAddress());
 	}
 
 	/** Returns AT version from the header bytes */
 	private short getVersion() {
-		byte[] creationBytes = deployATTransactionData.getCreationBytes();
+		byte[] creationBytes = deployAtTransactionData.getCreationBytes();
 		return (short) ((creationBytes[0] << 8) | (creationBytes[1] & 0xff)); // Big-endian
 	}
 
 	/** Make sure deployATTransactionData has an ATAddress */
-	private void ensureATAddress() throws DataException {
-		if (this.deployATTransactionData.getAtAddress() != null)
+	public static void ensureATAddress(DeployAtTransactionData deployAtTransactionData) throws DataException {
+		if (deployAtTransactionData.getAtAddress() != null)
 			return;
 
 		// Use transaction transformer
 		try {
-			String atAddress = Crypto.toATAddress(TransactionTransformer.toBytesForSigning(this.deployATTransactionData));
-			this.deployATTransactionData.setAtAddress(atAddress);
+			String atAddress = Crypto.toATAddress(TransactionTransformer.toBytesForSigning(deployAtTransactionData));
+			deployAtTransactionData.setAtAddress(atAddress);
 		} catch (TransformationException e) {
 			throw new DataException("Unable to generate AT address");
 		}
@@ -73,9 +75,9 @@ public class DeployAtTransaction extends Transaction {
 	// Navigation
 
 	public Account getATAccount() throws DataException {
-		ensureATAddress();
+		ensureATAddress(this.deployAtTransactionData);
 
-		return new Account(this.repository, this.deployATTransactionData.getAtAddress());
+		return new Account(this.repository, this.deployAtTransactionData.getAtAddress());
 	}
 
 	// Processing
@@ -83,30 +85,30 @@ public class DeployAtTransaction extends Transaction {
 	@Override
 	public ValidationResult isValid() throws DataException {
 		// Check name size bounds
-		int nameLength = Utf8.encodedLength(this.deployATTransactionData.getName());
+		int nameLength = Utf8.encodedLength(this.deployAtTransactionData.getName());
 		if (nameLength < 1 || nameLength > MAX_NAME_SIZE)
 			return ValidationResult.INVALID_NAME_LENGTH;
 
 		// Check description size bounds
-		int descriptionlength = Utf8.encodedLength(this.deployATTransactionData.getDescription());
+		int descriptionlength = Utf8.encodedLength(this.deployAtTransactionData.getDescription());
 		if (descriptionlength < 1 || descriptionlength > MAX_DESCRIPTION_SIZE)
 			return ValidationResult.INVALID_DESCRIPTION_LENGTH;
 
 		// Check AT-type size bounds
-		int atTypeLength = Utf8.encodedLength(this.deployATTransactionData.getAtType());
+		int atTypeLength = Utf8.encodedLength(this.deployAtTransactionData.getAtType());
 		if (atTypeLength < 1 || atTypeLength > MAX_AT_TYPE_SIZE)
 			return ValidationResult.INVALID_AT_TYPE_LENGTH;
 
 		// Check tags size bounds
-		int tagsLength = Utf8.encodedLength(this.deployATTransactionData.getTags());
+		int tagsLength = Utf8.encodedLength(this.deployAtTransactionData.getTags());
 		if (tagsLength < 1 || tagsLength > MAX_TAGS_SIZE)
 			return ValidationResult.INVALID_TAGS_LENGTH;
 
 		// Check amount is positive
-		if (this.deployATTransactionData.getAmount() <= 0)
+		if (this.deployAtTransactionData.getAmount() <= 0)
 			return ValidationResult.NEGATIVE_AMOUNT;
 
-		long assetId = this.deployATTransactionData.getAssetId();
+		long assetId = this.deployAtTransactionData.getAssetId();
 		AssetData assetData = this.repository.getAssetRepository().fromAssetId(assetId);
 		// Check asset even exists
 		if (assetData == null)
@@ -117,7 +119,7 @@ public class DeployAtTransaction extends Transaction {
 			return ValidationResult.ASSET_NOT_SPENDABLE;
 
 		// Check asset amount is integer if asset is not divisible
-		if (!assetData.isDivisible() && this.deployATTransactionData.getAmount() % Amounts.MULTIPLIER != 0)
+		if (!assetData.isDivisible() && this.deployAtTransactionData.getAmount() % Amounts.MULTIPLIER != 0)
 			return ValidationResult.INVALID_AMOUNT;
 
 		Account creator = this.getCreator();
@@ -125,15 +127,15 @@ public class DeployAtTransaction extends Transaction {
 		// Check creator has enough funds
 		if (assetId == Asset.QORT) {
 			// Simple case: amount and fee both in QORT
-			long minimumBalance = this.deployATTransactionData.getFee() + this.deployATTransactionData.getAmount();
+			long minimumBalance = this.deployAtTransactionData.getFee() + this.deployAtTransactionData.getAmount();
 
 			if (creator.getConfirmedBalance(Asset.QORT) < minimumBalance)
 				return ValidationResult.NO_BALANCE;
 		} else {
-			if (creator.getConfirmedBalance(Asset.QORT) < this.deployATTransactionData.getFee())
+			if (creator.getConfirmedBalance(Asset.QORT) < this.deployAtTransactionData.getFee())
 				return ValidationResult.NO_BALANCE;
 
-			if (creator.getConfirmedBalance(assetId) < this.deployATTransactionData.getAmount())
+			if (creator.getConfirmedBalance(assetId) < this.deployAtTransactionData.getAmount())
 				return ValidationResult.NO_BALANCE;
 		}
 
@@ -142,12 +144,12 @@ public class DeployAtTransaction extends Transaction {
 			return ValidationResult.INVALID_CREATION_BYTES;
 
 		// Check creation bytes are valid (for v2+)
-		this.ensureATAddress();
+		ensureATAddress(this.deployAtTransactionData);
 
 		// Just enough AT data to allow API to query initial balances, etc.
-		String atAddress = this.deployATTransactionData.getAtAddress();
-		byte[] creatorPublicKey = this.deployATTransactionData.getCreatorPublicKey();
-		long creation = this.deployATTransactionData.getTimestamp();
+		String atAddress = this.deployAtTransactionData.getAtAddress();
+		byte[] creatorPublicKey = this.deployAtTransactionData.getCreatorPublicKey();
+		long creation = this.deployAtTransactionData.getTimestamp();
 		ATData skeletonAtData = new ATData(atAddress, creatorPublicKey, creation, assetId);
 
 		int height = this.repository.getBlockRepository().getBlockchainHeight() + 1;
@@ -157,7 +159,15 @@ public class DeployAtTransaction extends Transaction {
 		QortalAtLoggerFactory loggerFactory = QortalAtLoggerFactory.getInstance();
 
 		try {
-			new MachineState(api, loggerFactory, this.deployATTransactionData.getCreationBytes());
+			MachineState state = new MachineState(api, loggerFactory, this.deployAtTransactionData.getCreationBytes());
+
+			byte[] codeBytes = state.getCodeBytes();
+			if (codeBytes == null || codeBytes.length > MAX_CODE_BYTES_LENGTH)
+				return ValidationResult.INVALID_CREATION_BYTES;
+
+			byte[] atStateBytes = state.toBytes();
+			if (atStateBytes == null || atStateBytes.length > MAX_AT_STATE_LENGTH)
+				return ValidationResult.INVALID_CREATION_BYTES;
 		} catch (IllegalArgumentException e) {
 			// Not valid
 			return ValidationResult.INVALID_CREATION_BYTES;
@@ -169,25 +179,25 @@ public class DeployAtTransaction extends Transaction {
 	@Override
 	public ValidationResult isProcessable() throws DataException {
 		Account creator = getCreator();
-		long assetId = this.deployATTransactionData.getAssetId();
+		long assetId = this.deployAtTransactionData.getAssetId();
 
 		// Check creator has enough funds
 		if (assetId == Asset.QORT) {
 			// Simple case: amount and fee both in QORT
-			long minimumBalance = this.deployATTransactionData.getFee() + this.deployATTransactionData.getAmount();
+			long minimumBalance = this.deployAtTransactionData.getFee() + this.deployAtTransactionData.getAmount();
 
 			if (creator.getConfirmedBalance(Asset.QORT) < minimumBalance)
 				return ValidationResult.NO_BALANCE;
 		} else {
-			if (creator.getConfirmedBalance(Asset.QORT) < this.deployATTransactionData.getFee())
+			if (creator.getConfirmedBalance(Asset.QORT) < this.deployAtTransactionData.getFee())
 				return ValidationResult.NO_BALANCE;
 
-			if (creator.getConfirmedBalance(assetId) < this.deployATTransactionData.getAmount())
+			if (creator.getConfirmedBalance(assetId) < this.deployAtTransactionData.getAmount())
 				return ValidationResult.NO_BALANCE;
 		}
 
 		// Check AT doesn't already exist
-		if (this.repository.getATRepository().exists(this.deployATTransactionData.getAtAddress()))
+		if (this.repository.getATRepository().exists(this.deployAtTransactionData.getAtAddress()))
 			return ValidationResult.AT_ALREADY_EXISTS;
 
 		return ValidationResult.OK;
@@ -195,40 +205,40 @@ public class DeployAtTransaction extends Transaction {
 
 	@Override
 	public void process() throws DataException {
-		this.ensureATAddress();
+		ensureATAddress(this.deployAtTransactionData);
 
 		// Deploy AT, saving into repository
-		AT at = new AT(this.repository, this.deployATTransactionData);
+		AT at = new AT(this.repository, this.deployAtTransactionData);
 		at.deploy();
 
-		long assetId = this.deployATTransactionData.getAssetId();
+		long assetId = this.deployAtTransactionData.getAssetId();
 
 		// Update creator's balance regarding initial payment to AT
 		Account creator = getCreator();
-		creator.modifyAssetBalance(assetId, - this.deployATTransactionData.getAmount());
+		creator.modifyAssetBalance(assetId, - this.deployAtTransactionData.getAmount());
 
 		// Update AT's reference, which also creates AT account
 		Account atAccount = this.getATAccount();
-		atAccount.setLastReference(this.deployATTransactionData.getSignature());
+		atAccount.setLastReference(this.deployAtTransactionData.getSignature());
 
 		// Update AT's balance
-		atAccount.setConfirmedBalance(assetId, this.deployATTransactionData.getAmount());
+		atAccount.setConfirmedBalance(assetId, this.deployAtTransactionData.getAmount());
 	}
 
 	@Override
 	public void orphan() throws DataException {
 		// Delete AT from repository
-		AT at = new AT(this.repository, this.deployATTransactionData);
+		AT at = new AT(this.repository, this.deployAtTransactionData);
 		at.undeploy();
 
-		long assetId = this.deployATTransactionData.getAssetId();
+		long assetId = this.deployAtTransactionData.getAssetId();
 
 		// Update creator's balance regarding initial payment to AT
 		Account creator = getCreator();
-		creator.modifyAssetBalance(assetId, this.deployATTransactionData.getAmount());
+		creator.modifyAssetBalance(assetId, this.deployAtTransactionData.getAmount());
 
 		// Delete AT's account (and hence its balance)
-		this.repository.getAccountRepository().delete(this.deployATTransactionData.getAtAddress());
+		this.repository.getAccountRepository().delete(this.deployAtTransactionData.getAtAddress());
 	}
 
 }

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

@@ -136,7 +136,7 @@ public class RewardShareTransaction extends Transaction {
 
 			// Deleting a non-existent reward-share makes no sense
 			if (isCancellingSharePercent)
-				return ValidationResult.INVALID_REWARD_SHARE_PERCENT;
+				return ValidationResult.REWARD_SHARE_UNKNOWN;
 
 			// Check the minting account hasn't reach maximum number of reward-shares
 			int rewardShareCount = this.repository.getAccountRepository().countRewardShares(creator.getPublicKey());

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

@@ -225,6 +225,7 @@ public abstract class Transaction {
 		AT_IS_FINISHED(71),
 		NO_FLAG_PERMISSION(72),
 		NOT_MINTING_ACCOUNT(73),
+		REWARD_SHARE_UNKNOWN(76),
 		INVALID_REWARD_SHARE_PERCENT(77),
 		PUBLIC_KEY_UNKNOWN(78),
 		INVALID_PUBLIC_KEY(79),

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

@@ -26,9 +26,26 @@ public class BitTwiddling {
 		return new byte[] { (byte) (value), (byte) (value >> 8), (byte) (value >> 16), (byte) (value >> 24) };
 	}
 
+	/** Convert int to big-endian byte array */
+	public static byte[] toBEByteArray(int value) {
+		return new byte[] { (byte) (value >> 24), (byte) (value >> 16), (byte) (value >> 8), (byte) (value) };
+	}
+
+	/** Convert long to big-endian byte array */
+	public static byte[] toBEByteArray(long value) {
+		return new byte[] { (byte) (value >> 56), (byte) (value >> 48), (byte) (value >> 40), (byte) (value >> 32),
+				(byte) (value >> 24), (byte) (value >> 16), (byte) (value >> 8), (byte) (value) };
+	}
+
 	/** Convert little-endian bytes to int */
-	public static int fromLEBytes(byte[] bytes, int offset) {
+	public static int intFromLEBytes(byte[] bytes, int offset) {
 		return (bytes[offset] & 0xff) | (bytes[offset + 1] & 0xff) << 8 | (bytes[offset + 2] & 0xff) << 16 | (bytes[offset + 3] & 0xff) << 24;
 	}
 
+	/** Convert big-endian bytes to long */
+	public static long longFromBEBytes(byte[] bytes, int start) {
+		return (bytes[start] & 0xffL) << 56 | (bytes[start + 1] & 0xffL) << 48 | (bytes[start + 2] & 0xffL) << 40 | (bytes[start + 3] & 0xffL) << 32
+				| (bytes[start + 4] & 0xffL) << 24 | (bytes[start + 5] & 0xffL) << 16 | (bytes[start + 6] & 0xffL) << 8 | (bytes[start + 7] & 0xffL);
+	}
+
 }

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

@@ -0,0 +1,31 @@
+package org.qortal.utils;
+
+import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class DaemonThreadFactory implements ThreadFactory {
+
+	private final String name;
+	private final AtomicInteger threadNumber = new AtomicInteger(1);
+
+	public DaemonThreadFactory(String name) {
+		this.name = name;
+	}
+
+	public DaemonThreadFactory() {
+		this(null);
+	}
+
+	@Override
+	public Thread newThread(Runnable runnable) {
+		Thread thread = Executors.defaultThreadFactory().newThread(runnable);
+		thread.setDaemon(true);
+
+		if (this.name != null)
+			thread.setName(this.name + "-" + this.threadNumber.getAndIncrement());
+
+		return thread;
+	}
+
+}

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

@@ -0,0 +1,24 @@
+package org.qortal.utils;
+
+import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class NamedThreadFactory implements ThreadFactory {
+
+	private final String name;
+	private final AtomicInteger threadNumber = new AtomicInteger(1);
+
+	public NamedThreadFactory(String name) {
+		this.name = name;
+	}
+
+	@Override
+	public Thread newThread(Runnable runnable) {
+		Thread thread = Executors.defaultThreadFactory().newThread(runnable);
+		thread.setName(this.name + "-" + this.threadNumber.getAndIncrement());
+
+		return thread;
+	}
+
+}

src/test/java/org/qortal/test/at/GetMessageLengthTests.java

@@ -0,0 +1,220 @@
+package org.qortal.test.at;
+
+import static org.junit.Assert.*;
+
+import java.nio.ByteBuffer;
+import java.util.Random;
+
+import org.ciyam.at.CompilationException;
+import org.ciyam.at.FunctionCode;
+import org.ciyam.at.MachineState;
+import org.ciyam.at.OpCode;
+import org.junit.Before;
+import org.junit.Test;
+import org.qortal.account.PrivateKeyAccount;
+import org.qortal.asset.Asset;
+import org.qortal.at.QortalFunctionCode;
+import org.qortal.data.at.ATStateData;
+import org.qortal.data.transaction.BaseTransactionData;
+import org.qortal.data.transaction.DeployAtTransactionData;
+import org.qortal.data.transaction.MessageTransactionData;
+import org.qortal.data.transaction.TransactionData;
+import org.qortal.group.Group;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+import org.qortal.test.common.AccountUtils;
+import org.qortal.test.common.BlockUtils;
+import org.qortal.test.common.Common;
+import org.qortal.test.common.TransactionUtils;
+import org.qortal.transaction.DeployAtTransaction;
+import org.qortal.transaction.MessageTransaction;
+import org.qortal.utils.BitTwiddling;
+
+public class GetMessageLengthTests extends Common {
+
+	private static final Random RANDOM = new Random();
+
+	@Before
+	public void before() throws DataException {
+		Common.useDefaultSettings();
+	}
+
+	@Test
+	public void testGetMessageLength() throws DataException {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			PrivateKeyAccount deployer = Common.getTestAccount(repository, "alice");
+
+			byte[] creationBytes = buildMessageLengthAT();
+
+			long fundingAmount = 1_00000000L;
+			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer, creationBytes, fundingAmount);
+			String atAddress = deployAtTransaction.getATAccount().getAddress();
+
+			// Send messages with known length
+			checkMessageLength(repository, deployer, atAddress, 1);
+			checkMessageLength(repository, deployer, atAddress, 10);
+			checkMessageLength(repository, deployer, atAddress, 32);
+			checkMessageLength(repository, deployer, atAddress, 99);
+
+			// Finally, send a payment instead and check returned length is -1
+			AccountUtils.pay(repository, deployer, atAddress, 123L);
+			// Mint another block so AT can process payment
+			BlockUtils.mintBlock(repository);
+
+			// Check AT result
+			ATStateData atStateData = repository.getATRepository().getLatestATState(atAddress);
+			byte[] stateData = atStateData.getStateData();
+
+			byte[] dataBytes = MachineState.extractDataBytes(stateData);
+
+			long extractedLength = BitTwiddling.longFromBEBytes(dataBytes, 0);
+
+			assertEquals(-1L, extractedLength);
+		}
+	}
+
+	private void checkMessageLength(Repository repository, PrivateKeyAccount sender, String atAddress, int messageLength) throws DataException {
+		byte[] testMessage = new byte[messageLength];
+		RANDOM.nextBytes(testMessage);
+
+		sendMessage(repository, sender, testMessage, atAddress);
+		// Mint another block so AT can process message
+		BlockUtils.mintBlock(repository);
+
+		// Check AT result
+		ATStateData atStateData = repository.getATRepository().getLatestATState(atAddress);
+		byte[] stateData = atStateData.getStateData();
+
+		byte[] dataBytes = MachineState.extractDataBytes(stateData);
+
+		long extractedLength = BitTwiddling.longFromBEBytes(dataBytes, 0);
+
+		assertEquals(messageLength, extractedLength);
+	}
+
+	private byte[] buildMessageLengthAT() {
+		// Labels for data segment addresses
+		int addrCounter = 0;
+
+		// Make result first for easier extraction
+		final int addrResult = addrCounter++;
+		final int addrLastTxTimestamp = addrCounter++;
+
+		// Data segment
+		ByteBuffer dataByteBuffer = ByteBuffer.allocate(addrCounter * MachineState.VALUE_SIZE);
+
+		// Code labels
+		Integer labelCheckTx = null;
+
+		ByteBuffer codeByteBuffer = ByteBuffer.allocate(512);
+
+		// Two-pass version
+		for (int pass = 0; pass < 2; ++pass) {
+			codeByteBuffer.clear();
+
+			try {
+				/* Initialization */
+
+				// Use AT creation 'timestamp' as starting point for finding transactions sent to AT
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_CREATION_TIMESTAMP, addrLastTxTimestamp));
+
+				// Set restart position to after this opcode
+				codeByteBuffer.put(OpCode.SET_PCS.compile());
+
+				/* Loop, waiting for message to AT */
+
+				// Find next transaction to this AT since the last one (if any)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PUT_TX_AFTER_TIMESTAMP_INTO_A, addrLastTxTimestamp));
+				// If no transaction found, A will be zero. If A is zero, set addrComparator to 1, otherwise 0.
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.CHECK_A_IS_ZERO, addrResult));
+				// If addrResult is zero (i.e. A is non-zero, transaction was found) then go check transaction
+				codeByteBuffer.put(OpCode.BZR_DAT.compile(addrResult, OpCode.calcOffset(codeByteBuffer, labelCheckTx)));
+				// Stop and wait for next block
+				codeByteBuffer.put(OpCode.STP_IMD.compile());
+
+				/* Check transaction */
+				labelCheckTx = codeByteBuffer.position();
+
+				// Update our 'last found transaction's timestamp' using 'timestamp' from transaction
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TIMESTAMP_FROM_TX_IN_A, addrLastTxTimestamp));
+				// Save message length
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(QortalFunctionCode.GET_MESSAGE_LENGTH_FROM_TX_IN_A.value, addrResult));
+
+				// Stop and wait for next block (and hence more transactions)
+				codeByteBuffer.put(OpCode.STP_IMD.compile());
+			} catch (CompilationException e) {
+				throw new IllegalStateException("Unable to compile AT?", e);
+			}
+		}
+
+		codeByteBuffer.flip();
+
+		byte[] codeBytes = new byte[codeByteBuffer.limit()];
+		codeByteBuffer.get(codeBytes);
+
+		final short ciyamAtVersion = 2;
+		final short numCallStackPages = 0;
+		final short numUserStackPages = 0;
+		final long minActivationAmount = 0L;
+
+		return MachineState.toCreationBytes(ciyamAtVersion, codeBytes, dataByteBuffer.array(), numCallStackPages, numUserStackPages, minActivationAmount);
+	}
+
+	private DeployAtTransaction doDeploy(Repository repository, PrivateKeyAccount deployer, byte[] creationBytes, long fundingAmount) throws DataException {
+		long txTimestamp = System.currentTimeMillis();
+		byte[] lastReference = deployer.getLastReference();
+
+		if (lastReference == null) {
+			System.err.println(String.format("Qortal account %s has no last reference", deployer.getAddress()));
+			System.exit(2);
+		}
+
+		Long fee = null;
+		String name = "Test AT";
+		String description = "Test AT";
+		String atType = "Test";
+		String tags = "TEST";
+
+		BaseTransactionData baseTransactionData = new BaseTransactionData(txTimestamp, Group.NO_GROUP, lastReference, deployer.getPublicKey(), fee, null);
+		TransactionData deployAtTransactionData = new DeployAtTransactionData(baseTransactionData, name, description, atType, tags, creationBytes, fundingAmount, Asset.QORT);
+
+		DeployAtTransaction deployAtTransaction = new DeployAtTransaction(repository, deployAtTransactionData);
+
+		fee = deployAtTransaction.calcRecommendedFee();
+		deployAtTransactionData.setFee(fee);
+
+		TransactionUtils.signAndMint(repository, deployAtTransactionData, deployer);
+
+		return deployAtTransaction;
+	}
+
+	private MessageTransaction sendMessage(Repository repository, PrivateKeyAccount sender, byte[] data, String recipient) throws DataException {
+		long txTimestamp = System.currentTimeMillis();
+		byte[] lastReference = sender.getLastReference();
+
+		if (lastReference == null) {
+			System.err.println(String.format("Qortal account %s has no last reference", sender.getAddress()));
+			System.exit(2);
+		}
+
+		Long fee = null;
+		int version = 4;
+		int nonce = 0;
+		long amount = 0;
+		Long assetId = null; // because amount is zero
+
+		BaseTransactionData baseTransactionData = new BaseTransactionData(txTimestamp, Group.NO_GROUP, lastReference, sender.getPublicKey(), fee, null);
+		TransactionData messageTransactionData = new MessageTransactionData(baseTransactionData, version, nonce, recipient, amount, assetId, data, false, false);
+
+		MessageTransaction messageTransaction = new MessageTransaction(repository, messageTransactionData);
+
+		fee = messageTransaction.calcRecommendedFee();
+		messageTransactionData.setFee(fee);
+
+		TransactionUtils.signAndMint(repository, messageTransactionData, sender);
+
+		return messageTransaction;
+	}
+
+}

src/test/java/org/qortal/test/at/GetNextTransactionTests.java

@@ -0,0 +1,266 @@
+package org.qortal.test.at;
+
+import static org.junit.Assert.*;
+
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.List;
+
+import org.ciyam.at.CompilationException;
+import org.ciyam.at.FunctionCode;
+import org.ciyam.at.MachineState;
+import org.ciyam.at.OpCode;
+import org.ciyam.at.Timestamp;
+import org.junit.Before;
+import org.junit.Test;
+import org.qortal.account.PrivateKeyAccount;
+import org.qortal.asset.Asset;
+import org.qortal.block.Block;
+import org.qortal.data.at.ATStateData;
+import org.qortal.data.block.BlockData;
+import org.qortal.data.transaction.BaseTransactionData;
+import org.qortal.data.transaction.DeployAtTransactionData;
+import org.qortal.data.transaction.MessageTransactionData;
+import org.qortal.data.transaction.TransactionData;
+import org.qortal.group.Group;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+import org.qortal.test.common.BlockUtils;
+import org.qortal.test.common.Common;
+import org.qortal.test.common.TransactionUtils;
+import org.qortal.transaction.DeployAtTransaction;
+import org.qortal.transaction.MessageTransaction;
+import org.qortal.transaction.Transaction;
+import org.qortal.utils.BitTwiddling;
+
+public class GetNextTransactionTests extends Common {
+
+	@Before
+	public void before() throws DataException {
+		Common.useDefaultSettings();
+	}
+
+	@Test
+	public void testGetNextTransaction() throws DataException {
+		byte[] data = new byte[] { 0x44 };
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			PrivateKeyAccount deployer = Common.getTestAccount(repository, "alice");
+
+			byte[] creationBytes = buildGetNextTransactionAT();
+
+			long fundingAmount = 1_00000000L;
+			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer, creationBytes, fundingAmount);
+			String atAddress = deployAtTransaction.getATAccount().getAddress();
+
+			byte[] rawNextTimestamp = new byte[32];
+			Transaction transaction;
+
+			// Confirm initial value is zero
+			extractNextTxTimestamp(repository, atAddress, rawNextTimestamp);
+			assertArrayEquals(new byte[32], rawNextTimestamp);
+
+			// Send message to someone other than AT
+			sendMessage(repository, deployer, data, deployer.getAddress());
+			BlockUtils.mintBlock(repository);
+
+			// Confirm AT does not find message
+			extractNextTxTimestamp(repository, atAddress, rawNextTimestamp);
+			assertArrayEquals(new byte[32], rawNextTimestamp);
+
+			// Send message to AT
+			transaction = sendMessage(repository, deployer, data, atAddress);
+			BlockUtils.mintBlock(repository);
+
+			// Confirm AT finds message
+			BlockUtils.mintBlock(repository);
+			assertTimestamp(repository, atAddress, transaction);
+
+			// Mint a few blocks, then send non-AT message, followed by AT message
+			for (int i = 0; i < 5; ++i)
+				BlockUtils.mintBlock(repository);
+			sendMessage(repository, deployer, data, deployer.getAddress());
+			transaction = sendMessage(repository, deployer, data, atAddress);
+			BlockUtils.mintBlock(repository);
+
+			// Confirm AT finds message
+			BlockUtils.mintBlock(repository);
+			assertTimestamp(repository, atAddress, transaction);
+		}
+	}
+
+	private byte[] buildGetNextTransactionAT() {
+		// Labels for data segment addresses
+		int addrCounter = 0;
+
+		// Beginning of data segment for easy extraction
+		final int addrNextTx = addrCounter;
+		addrCounter += 4;
+
+		final int addrNextTxIndex = addrCounter++;
+
+		final int addrLastTxTimestamp = addrCounter++;
+
+		// Data segment
+		ByteBuffer dataByteBuffer = ByteBuffer.allocate(addrCounter * MachineState.VALUE_SIZE);
+
+		// skip addrNextTx
+		dataByteBuffer.position(dataByteBuffer.position() + 4 * MachineState.VALUE_SIZE);
+
+		// Store pointer to addrNextTx at addrNextTxIndex
+		dataByteBuffer.putLong(addrNextTx);
+
+		ByteBuffer codeByteBuffer = ByteBuffer.allocate(512);
+
+		// Two-pass version
+		for (int pass = 0; pass < 2; ++pass) {
+			codeByteBuffer.clear();
+
+			try {
+				/* Initialization */
+
+				// Use AT creation 'timestamp' as starting point for finding transactions sent to AT
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_CREATION_TIMESTAMP, addrLastTxTimestamp));
+
+				// Set restart position to after this opcode
+				codeByteBuffer.put(OpCode.SET_PCS.compile());
+
+				/* Loop, waiting for message to AT */
+
+				// Find next transaction to this AT since the last one (if any)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PUT_TX_AFTER_TIMESTAMP_INTO_A, addrLastTxTimestamp));
+				// Copy A to data segment, starting at addrNextTx (as pointed to by addrNextTxIndex)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_A_IND, addrNextTxIndex));
+				// Stop if timestamp part of A is zero
+				codeByteBuffer.put(OpCode.STZ_DAT.compile(addrNextTx));
+
+				// Update our 'last found transaction's timestamp' using 'timestamp' from transaction
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TIMESTAMP_FROM_TX_IN_A, addrLastTxTimestamp));
+				// Stop and wait for next block
+				codeByteBuffer.put(OpCode.STP_IMD.compile());
+
+			} catch (CompilationException e) {
+				throw new IllegalStateException("Unable to compile AT?", e);
+			}
+		}
+
+		codeByteBuffer.flip();
+
+		byte[] codeBytes = new byte[codeByteBuffer.limit()];
+		codeByteBuffer.get(codeBytes);
+
+		final short ciyamAtVersion = 2;
+		final short numCallStackPages = 0;
+		final short numUserStackPages = 0;
+		final long minActivationAmount = 0L;
+
+		return MachineState.toCreationBytes(ciyamAtVersion, codeBytes, dataByteBuffer.array(), numCallStackPages, numUserStackPages, minActivationAmount);
+	}
+
+	private DeployAtTransaction doDeploy(Repository repository, PrivateKeyAccount deployer, byte[] creationBytes, long fundingAmount) throws DataException {
+		long txTimestamp = System.currentTimeMillis();
+		byte[] lastReference = deployer.getLastReference();
+
+		if (lastReference == null) {
+			System.err.println(String.format("Qortal account %s has no last reference", deployer.getAddress()));
+			System.exit(2);
+		}
+
+		Long fee = null;
+		String name = "Test AT";
+		String description = "Test AT";
+		String atType = "Test";
+		String tags = "TEST";
+
+		BaseTransactionData baseTransactionData = new BaseTransactionData(txTimestamp, Group.NO_GROUP, lastReference, deployer.getPublicKey(), fee, null);
+		TransactionData deployAtTransactionData = new DeployAtTransactionData(baseTransactionData, name, description, atType, tags, creationBytes, fundingAmount, Asset.QORT);
+
+		DeployAtTransaction deployAtTransaction = new DeployAtTransaction(repository, deployAtTransactionData);
+
+		fee = deployAtTransaction.calcRecommendedFee();
+		deployAtTransactionData.setFee(fee);
+
+		TransactionUtils.signAndMint(repository, deployAtTransactionData, deployer);
+
+		return deployAtTransaction;
+	}
+
+	private void extractNextTxTimestamp(Repository repository, String atAddress, byte[] rawNextTimestamp) throws DataException {
+		// Check AT result
+		ATStateData atStateData = repository.getATRepository().getLatestATState(atAddress);
+		byte[] stateData = atStateData.getStateData();
+
+		byte[] dataBytes = MachineState.extractDataBytes(stateData);
+
+		System.arraycopy(dataBytes, 0, rawNextTimestamp, 0, rawNextTimestamp.length);
+	}
+
+	private MessageTransaction sendMessage(Repository repository, PrivateKeyAccount sender, byte[] data, String recipient) throws DataException {
+		long txTimestamp = System.currentTimeMillis();
+		byte[] lastReference = sender.getLastReference();
+
+		if (lastReference == null) {
+			System.err.println(String.format("Qortal account %s has no last reference", sender.getAddress()));
+			System.exit(2);
+		}
+
+		Long fee = null;
+		int version = 4;
+		int nonce = 0;
+		long amount = 0;
+		Long assetId = null; // because amount is zero
+
+		BaseTransactionData baseTransactionData = new BaseTransactionData(txTimestamp, Group.NO_GROUP, lastReference, sender.getPublicKey(), fee, null);
+		TransactionData messageTransactionData = new MessageTransactionData(baseTransactionData, version, nonce, recipient, amount, assetId, data, false, false);
+
+		MessageTransaction messageTransaction = new MessageTransaction(repository, messageTransactionData);
+
+		fee = messageTransaction.calcRecommendedFee();
+		messageTransactionData.setFee(fee);
+
+		TransactionUtils.signAndImportValid(repository, messageTransactionData, sender);
+
+		return messageTransaction;
+	}
+
+	private void assertTimestamp(Repository repository, String atAddress, Transaction transaction) throws DataException {
+		int height = transaction.getHeight();
+		byte[] transactionSignature = transaction.getTransactionData().getSignature();
+
+		BlockData blockData = repository.getBlockRepository().fromHeight(height);
+		assertNotNull(blockData);
+
+		Block block = new Block(repository, blockData);
+
+		List<Transaction> blockTransactions = block.getTransactions();
+		int sequence;
+		for (sequence = blockTransactions.size() - 1; sequence >= 0; --sequence)
+			if (Arrays.equals(blockTransactions.get(sequence).getTransactionData().getSignature(), transactionSignature))
+				break;
+
+		assertNotSame(-1, sequence);
+
+		byte[] rawNextTimestamp = new byte[32];
+		extractNextTxTimestamp(repository, atAddress, rawNextTimestamp);
+
+		Timestamp expectedTimestamp = new Timestamp(height, sequence);
+		Timestamp actualTimestamp = new Timestamp(BitTwiddling.longFromBEBytes(rawNextTimestamp, 0));
+
+		assertEquals(String.format("Expected height %d, seq %d but was height %d, seq %d",
+					height, sequence,
+					actualTimestamp.blockHeight, actualTimestamp.transactionSequence
+				),
+				expectedTimestamp.longValue(),
+				actualTimestamp.longValue());
+
+		byte[] expectedPartialSignature = new byte[24];
+		System.arraycopy(transactionSignature, 8, expectedPartialSignature, 0, expectedPartialSignature.length);
+
+		byte[] actualPartialSignature = new byte[24];
+		System.arraycopy(rawNextTimestamp, 8, actualPartialSignature, 0, actualPartialSignature.length);
+
+		assertArrayEquals(expectedPartialSignature, actualPartialSignature);
+	}
+
+}

src/test/java/org/qortal/test/at/GetPartialMessageTests.java

@@ -0,0 +1,219 @@
+package org.qortal.test.at;
+
+import static org.junit.Assert.*;
+
+import java.nio.ByteBuffer;
+
+import org.ciyam.at.CompilationException;
+import org.ciyam.at.FunctionCode;
+import org.ciyam.at.MachineState;
+import org.ciyam.at.OpCode;
+import org.junit.Before;
+import org.junit.Test;
+import org.qortal.account.PrivateKeyAccount;
+import org.qortal.asset.Asset;
+import org.qortal.at.QortalFunctionCode;
+import org.qortal.data.at.ATStateData;
+import org.qortal.data.transaction.BaseTransactionData;
+import org.qortal.data.transaction.DeployAtTransactionData;
+import org.qortal.data.transaction.MessageTransactionData;
+import org.qortal.data.transaction.TransactionData;
+import org.qortal.group.Group;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+import org.qortal.test.common.BlockUtils;
+import org.qortal.test.common.Common;
+import org.qortal.test.common.TransactionUtils;
+import org.qortal.transaction.DeployAtTransaction;
+import org.qortal.transaction.MessageTransaction;
+
+public class GetPartialMessageTests extends Common {
+
+	@Before
+	public void before() throws DataException {
+		Common.useDefaultSettings();
+	}
+
+	@Test
+	public void testGetPartialMessage() throws DataException {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			PrivateKeyAccount deployer = Common.getTestAccount(repository, "alice");
+
+			byte[] messageData = "The quick brown fox jumped over the lazy dog.".getBytes();
+			int[] offsets = new int[] { 0, 7, 32, 44, messageData.length };
+
+			byte[] creationBytes = buildGetPartialMessageAT(offsets);
+
+			long fundingAmount = 1_00000000L;
+			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer, creationBytes, fundingAmount);
+			String atAddress = deployAtTransaction.getATAccount().getAddress();
+
+			sendMessage(repository, deployer, messageData, atAddress);
+
+			for (int offset : offsets) {
+				// Mint another block so AT can process message
+				BlockUtils.mintBlock(repository);
+
+				byte[] expectedData = new byte[32];
+				int byteCount = Math.min(32, messageData.length - offset);
+				System.arraycopy(messageData, offset, expectedData, 0, byteCount);
+
+				// Check AT result
+				ATStateData atStateData = repository.getATRepository().getLatestATState(atAddress);
+				byte[] stateData = atStateData.getStateData();
+
+				byte[] dataBytes = MachineState.extractDataBytes(stateData);
+
+				byte[] actualData = new byte[32];
+				System.arraycopy(dataBytes, MachineState.VALUE_SIZE, actualData, 0, 32);
+
+				assertArrayEquals(expectedData, actualData);
+			}
+		}
+	}
+
+	private byte[] buildGetPartialMessageAT(int... offsets) {
+		// Labels for data segment addresses
+		int addrCounter = 0;
+
+		final int addrCopyOfBIndex = addrCounter++;
+
+		// 2nd position for easy extraction
+		final int addrCopyOfB = addrCounter;
+		addrCounter += 4;
+
+		final int addrResult = addrCounter++;
+		final int addrLastTxTimestamp = addrCounter++;
+		final int addrOffset = addrCounter++;
+
+		// Data segment
+		ByteBuffer dataByteBuffer = ByteBuffer.allocate(addrCounter * MachineState.VALUE_SIZE);
+
+		dataByteBuffer.putLong(addrCopyOfB);
+
+		// Code labels
+		Integer labelCheckTx = null;
+
+		ByteBuffer codeByteBuffer = ByteBuffer.allocate(512);
+
+		// Two-pass version
+		for (int pass = 0; pass < 2; ++pass) {
+			codeByteBuffer.clear();
+
+			try {
+				/* Initialization */
+
+				// Use AT creation 'timestamp' as starting point for finding transactions sent to AT
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_CREATION_TIMESTAMP, addrLastTxTimestamp));
+
+				// Set restart position to after this opcode
+				codeByteBuffer.put(OpCode.SET_PCS.compile());
+
+				/* Loop, waiting for message to AT */
+
+				// Find next transaction to this AT since the last one (if any)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PUT_TX_AFTER_TIMESTAMP_INTO_A, addrLastTxTimestamp));
+				// If no transaction found, A will be zero. If A is zero, set addrComparator to 1, otherwise 0.
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.CHECK_A_IS_ZERO, addrResult));
+				// If addrResult is zero (i.e. A is non-zero, transaction was found) then go check transaction
+				codeByteBuffer.put(OpCode.BZR_DAT.compile(addrResult, OpCode.calcOffset(codeByteBuffer, labelCheckTx)));
+				// Stop and wait for next block
+				codeByteBuffer.put(OpCode.STP_IMD.compile());
+
+				/* Check transaction */
+				labelCheckTx = codeByteBuffer.position();
+
+				// Generate code per offset
+				for (int i = 0; i < offsets.length; ++i) {
+					if (i > 0)
+						// Wait for next block
+						codeByteBuffer.put(OpCode.SLP_IMD.compile());
+
+					// Set offset
+					codeByteBuffer.put(OpCode.SET_VAL.compile(addrOffset, offsets[i]));
+
+					// Extract partial message
+					codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(QortalFunctionCode.PUT_PARTIAL_MESSAGE_FROM_TX_IN_A_INTO_B.value, addrOffset));
+
+					// Copy B to data segment
+					codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrCopyOfBIndex));
+				}
+
+				// We're done
+				codeByteBuffer.put(OpCode.FIN_IMD.compile());
+			} catch (CompilationException e) {
+				throw new IllegalStateException("Unable to compile AT?", e);
+			}
+		}
+
+		codeByteBuffer.flip();
+
+		byte[] codeBytes = new byte[codeByteBuffer.limit()];
+		codeByteBuffer.get(codeBytes);
+
+		final short ciyamAtVersion = 2;
+		final short numCallStackPages = 0;
+		final short numUserStackPages = 0;
+		final long minActivationAmount = 0L;
+
+		return MachineState.toCreationBytes(ciyamAtVersion, codeBytes, dataByteBuffer.array(), numCallStackPages, numUserStackPages, minActivationAmount);
+	}
+
+	private DeployAtTransaction doDeploy(Repository repository, PrivateKeyAccount deployer, byte[] creationBytes, long fundingAmount) throws DataException {
+		long txTimestamp = System.currentTimeMillis();
+		byte[] lastReference = deployer.getLastReference();
+
+		if (lastReference == null) {
+			System.err.println(String.format("Qortal account %s has no last reference", deployer.getAddress()));
+			System.exit(2);
+		}
+
+		Long fee = null;
+		String name = "Test AT";
+		String description = "Test AT";
+		String atType = "Test";
+		String tags = "TEST";
+
+		BaseTransactionData baseTransactionData = new BaseTransactionData(txTimestamp, Group.NO_GROUP, lastReference, deployer.getPublicKey(), fee, null);
+		TransactionData deployAtTransactionData = new DeployAtTransactionData(baseTransactionData, name, description, atType, tags, creationBytes, fundingAmount, Asset.QORT);
+
+		DeployAtTransaction deployAtTransaction = new DeployAtTransaction(repository, deployAtTransactionData);
+
+		fee = deployAtTransaction.calcRecommendedFee();
+		deployAtTransactionData.setFee(fee);
+
+		TransactionUtils.signAndMint(repository, deployAtTransactionData, deployer);
+
+		return deployAtTransaction;
+	}
+
+	private MessageTransaction sendMessage(Repository repository, PrivateKeyAccount sender, byte[] data, String recipient) throws DataException {
+		long txTimestamp = System.currentTimeMillis();
+		byte[] lastReference = sender.getLastReference();
+
+		if (lastReference == null) {
+			System.err.println(String.format("Qortal account %s has no last reference", sender.getAddress()));
+			System.exit(2);
+		}
+
+		Long fee = null;
+		int version = 4;
+		int nonce = 0;
+		long amount = 0;
+		Long assetId = null; // because amount is zero
+
+		BaseTransactionData baseTransactionData = new BaseTransactionData(txTimestamp, Group.NO_GROUP, lastReference, sender.getPublicKey(), fee, null);
+		TransactionData messageTransactionData = new MessageTransactionData(baseTransactionData, version, nonce, recipient, amount, assetId, data, false, false);
+
+		MessageTransaction messageTransaction = new MessageTransaction(repository, messageTransactionData);
+
+		fee = messageTransaction.calcRecommendedFee();
+		messageTransactionData.setFee(fee);
+
+		TransactionUtils.signAndMint(repository, messageTransactionData, sender);
+
+		return messageTransaction;
+	}
+
+}

src/test/java/org/qortal/test/btcacct/AtTests.java

@@ -1,7 +1,6 @@
 package org.qortal.test.btcacct;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.*;
 
 import java.time.Instant;
 import java.time.LocalDateTime;
@@ -10,14 +9,15 @@ import java.time.format.DateTimeFormatter;
 import java.time.format.FormatStyle;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Random;
 import java.util.function.Function;
 
-import org.bitcoinj.core.Base58;
 import org.junit.Before;
 import org.junit.Test;
 import org.qortal.account.Account;
 import org.qortal.account.PrivateKeyAccount;
 import org.qortal.asset.Asset;
+import org.qortal.block.Block;
 import org.qortal.crosschain.BTCACCT;
 import org.qortal.crypto.Crypto;
 import org.qortal.data.at.ATData;
@@ -43,14 +43,18 @@ import com.google.common.primitives.Bytes;
 
 public class AtTests extends Common {
 
-	public static final byte[] secret = "This string is exactly 32 bytes!".getBytes();
-	public static final byte[] secretHash = Crypto.hash160(secret); // daf59884b4d1aec8c1b17102530909ee43c0151a
-	public static final int refundTimeout = 10; // blocks
-	public static final long initialPayout = 100000L;
+	public static final byte[] secretA = "This string is exactly 32 bytes!".getBytes();
+	public static final byte[] hashOfSecretA = Crypto.hash160(secretA); // daf59884b4d1aec8c1b17102530909ee43c0151a
+	public static final byte[] secretB = "This string is roughly 32 bytes?".getBytes();
+	public static final byte[] hashOfSecretB = Crypto.hash160(secretB); // 31f0dd71decf59bbc8ef0661f4030479255cfa58
+	public static final byte[] bitcoinPublicKeyHash = HashCode.fromString("bb00bb11bb22bb33bb44bb55bb66bb77bb88bb99").asBytes();
+	public static final int tradeTimeout = 20; // blocks
 	public static final long redeemAmount = 80_40200000L;
 	public static final long fundingAmount = 123_45600000L;
 	public static final long bitcoinAmount = 864200L;
 
+	private static final Random RANDOM = new Random();
+
 	@Before
 	public void beforeTest() throws DataException {
 		Common.useDefaultSettings();
@@ -58,9 +62,9 @@ public class AtTests extends Common {
 
 	@Test
 	public void testCompile() {
-		Account deployer = Common.getTestAccount(null, "chloe");
+		PrivateKeyAccount tradeAccount = createTradeAccount(null);
 
-		byte[] creationBytes = BTCACCT.buildQortalAT(deployer.getAddress(), secretHash, refundTimeout, initialPayout, redeemAmount, bitcoinAmount);
+		byte[] creationBytes = BTCACCT.buildQortalAT(tradeAccount.getAddress(), bitcoinPublicKeyHash, hashOfSecretB, redeemAmount, bitcoinAmount, tradeTimeout);
 		System.out.println("CIYAM AT creation bytes: " + HashCode.fromBytes(creationBytes).toString());
 	}
 
@@ -68,12 +72,14 @@ public class AtTests extends Common {
 	public void testDeploy() throws DataException {
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			PrivateKeyAccount deployer = Common.getTestAccount(repository, "chloe");
-			PrivateKeyAccount recipient = Common.getTestAccount(repository, "dilbert");
+			PrivateKeyAccount tradeAccount = createTradeAccount(repository);
+
+			PrivateKeyAccount partner = Common.getTestAccount(repository, "dilbert");
 
 			long deployersInitialBalance = deployer.getConfirmedBalance(Asset.QORT);
-			long recipientsInitialBalance = recipient.getConfirmedBalance(Asset.QORT);
+			long partnersInitialBalance = partner.getConfirmedBalance(Asset.QORT);
 
-			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer);
+			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer, tradeAccount.getAddress());
 
 			long expectedBalance = deployersInitialBalance - fundingAmount - deployAtTransaction.getTransactionData().getFee();
 			long actualBalance = deployer.getConfirmedBalance(Asset.QORT);
@@ -85,10 +91,10 @@ public class AtTests extends Common {
 
 			assertEquals("AT's post-deployment balance incorrect", expectedBalance, actualBalance);
 
-			expectedBalance = recipientsInitialBalance;
-			actualBalance = recipient.getConfirmedBalance(Asset.QORT);
+			expectedBalance = partnersInitialBalance;
+			actualBalance = partner.getConfirmedBalance(Asset.QORT);
 
-			assertEquals("Recipient's post-deployment balance incorrect", expectedBalance, actualBalance);
+			assertEquals("Partner's post-deployment balance incorrect", expectedBalance, actualBalance);
 
 			// Test orphaning
 			BlockUtils.orphanLastBlock(repository);
@@ -103,10 +109,10 @@ public class AtTests extends Common {
 
 			assertEquals("AT's post-orphan/pre-deployment balance incorrect", expectedBalance, actualBalance);
 
-			expectedBalance = recipientsInitialBalance;
-			actualBalance = recipient.getConfirmedBalance(Asset.QORT);
+			expectedBalance = partnersInitialBalance;
+			actualBalance = partner.getConfirmedBalance(Asset.QORT);
 
-			assertEquals("Recipient's post-orphan/pre-deployment balance incorrect", expectedBalance, actualBalance);
+			assertEquals("Partner's post-orphan/pre-deployment balance incorrect", expectedBalance, actualBalance);
 		}
 	}
 
@@ -115,26 +121,39 @@ public class AtTests extends Common {
 	public void testOfferCancel() throws DataException {
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			PrivateKeyAccount deployer = Common.getTestAccount(repository, "chloe");
-			PrivateKeyAccount recipient = Common.getTestAccount(repository, "dilbert");
+			PrivateKeyAccount tradeAccount = createTradeAccount(repository);
+
+			PrivateKeyAccount partner = Common.getTestAccount(repository, "dilbert");
 
 			long deployersInitialBalance = deployer.getConfirmedBalance(Asset.QORT);
-			long recipientsInitialBalance = recipient.getConfirmedBalance(Asset.QORT);
+			long partnersInitialBalance = partner.getConfirmedBalance(Asset.QORT);
 
-			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer);
+			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer, tradeAccount.getAddress());
 			Account at = deployAtTransaction.getATAccount();
 			String atAddress = at.getAddress();
 
 			long deployAtFee = deployAtTransaction.getTransactionData().getFee();
 			long deployersPostDeploymentBalance = deployersInitialBalance - fundingAmount - deployAtFee;
 
-			// Send creator's address to AT
-			byte[] recipientAddressBytes = Bytes.ensureCapacity(Base58.decode(deployer.getAddress()), 32, 0);
-			MessageTransaction messageTransaction = sendMessage(repository, deployer, recipientAddressBytes, atAddress);
+			// Send creator's address to AT, instead of typical partner's address
+			byte[] messageData = BTCACCT.buildCancelMessage(deployer.getAddress());
+			MessageTransaction messageTransaction = sendMessage(repository, deployer, messageData, atAddress);
 			long messageFee = messageTransaction.getTransactionData().getFee();
 
-			// Refund should happen 1st block after receiving recipient address
+			// AT should process 'cancel' message in next block
 			BlockUtils.mintBlock(repository);
 
+			describeAt(repository, atAddress);
+
+			// Check AT is finished
+			ATData atData = repository.getATRepository().fromATAddress(atAddress);
+			assertTrue(atData.getIsFinished());
+
+			// AT should be in CANCELLED mode
+			CrossChainTradeData tradeData = BTCACCT.populateTradeData(repository, atData);
+			assertEquals(BTCACCT.Mode.CANCELLED, tradeData.mode);
+
+			// Check balances
 			long expectedMinimumBalance = deployersPostDeploymentBalance;
 			long expectedMaximumBalance = deployersInitialBalance - deployAtFee - messageFee;
 
@@ -143,11 +162,10 @@ public class AtTests extends Common {
 			assertTrue(String.format("Deployer's balance %s should be above minimum %s", actualBalance, expectedMinimumBalance), actualBalance > expectedMinimumBalance);
 			assertTrue(String.format("Deployer's balance %s should be below maximum %s", actualBalance, expectedMaximumBalance), actualBalance < expectedMaximumBalance);
 
-			describeAt(repository, atAddress);
-
 			// Test orphaning
 			BlockUtils.orphanLastBlock(repository);
 
+			// Check balances
 			long expectedBalance = deployersPostDeploymentBalance - messageFee;
 			actualBalance = deployer.getConfirmedBalance(Asset.QORT);
 
@@ -157,71 +175,144 @@ public class AtTests extends Common {
 
 	@SuppressWarnings("unused")
 	@Test
-	public void testInitialPayment() throws DataException {
+	public void testOfferCancelInvalidLength() throws DataException {
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			PrivateKeyAccount deployer = Common.getTestAccount(repository, "chloe");
-			PrivateKeyAccount recipient = Common.getTestAccount(repository, "dilbert");
+			PrivateKeyAccount tradeAccount = createTradeAccount(repository);
+
+			PrivateKeyAccount partner = Common.getTestAccount(repository, "dilbert");
 
 			long deployersInitialBalance = deployer.getConfirmedBalance(Asset.QORT);
-			long recipientsInitialBalance = recipient.getConfirmedBalance(Asset.QORT);
+			long partnersInitialBalance = partner.getConfirmedBalance(Asset.QORT);
 
-			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer);
+			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer, tradeAccount.getAddress());
 			Account at = deployAtTransaction.getATAccount();
 			String atAddress = at.getAddress();
 
-			// Send recipient's address to AT
-			byte[] recipientAddressBytes = Bytes.ensureCapacity(Base58.decode(recipient.getAddress()), 32, 0);
-			MessageTransaction messageTransaction = sendMessage(repository, deployer, recipientAddressBytes, atAddress);
+			long deployAtFee = deployAtTransaction.getTransactionData().getFee();
+			long deployersPostDeploymentBalance = deployersInitialBalance - fundingAmount - deployAtFee;
 
-			// Initial payment should happen 1st block after receiving recipient address
+			// Instead of sending creator's address to AT, send too-short/invalid message
+			byte[] messageData = new byte[7];
+			RANDOM.nextBytes(messageData);
+			MessageTransaction messageTransaction = sendMessage(repository, deployer, messageData, atAddress);
+			long messageFee = messageTransaction.getTransactionData().getFee();
+
+			// AT should process 'cancel' message in next block
+			// As message is too short, it will be padded to 32bytes but cancel code doesn't care about message content, so should be ok
 			BlockUtils.mintBlock(repository);
 
-			long expectedBalance = recipientsInitialBalance + initialPayout;
-			long actualBalance = recipient.getConfirmedBalance(Asset.QORT);
-
-			assertEquals("Recipient's post-initial-payout balance incorrect", expectedBalance, actualBalance);
-
 			describeAt(repository, atAddress);
 
-			// Test orphaning
-			BlockUtils.orphanLastBlock(repository);
+			// Check AT is finished
+			ATData atData = repository.getATRepository().fromATAddress(atAddress);
+			assertTrue(atData.getIsFinished());
 
-			expectedBalance = recipientsInitialBalance;
-			actualBalance = recipient.getConfirmedBalance(Asset.QORT);
-
-			assertEquals("Recipient's pre-initial-payout balance incorrect", expectedBalance, actualBalance);
+			// AT should be in CANCELLED mode
+			CrossChainTradeData tradeData = BTCACCT.populateTradeData(repository, atData);
+			assertEquals(BTCACCT.Mode.CANCELLED, tradeData.mode);
 		}
 	}
 
-	// TEST SENDING RECIPIENT ADDRESS BUT NOT FROM AT CREATOR (SHOULD BE IGNORED)
+	@SuppressWarnings("unused")
+	@Test
+	public void testTradingInfoProcessing() throws DataException {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			PrivateKeyAccount deployer = Common.getTestAccount(repository, "chloe");
+			PrivateKeyAccount tradeAccount = createTradeAccount(repository);
+
+			PrivateKeyAccount partner = Common.getTestAccount(repository, "dilbert");
+
+			long deployersInitialBalance = deployer.getConfirmedBalance(Asset.QORT);
+			long partnersInitialBalance = partner.getConfirmedBalance(Asset.QORT);
+
+			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer, tradeAccount.getAddress());
+			Account at = deployAtTransaction.getATAccount();
+			String atAddress = at.getAddress();
+
+			long partnersOfferMessageTransactionTimestamp = System.currentTimeMillis();
+			int lockTimeA = calcTestLockTimeA(partnersOfferMessageTransactionTimestamp);
+			int lockTimeB = BTCACCT.calcLockTimeB(partnersOfferMessageTransactionTimestamp, lockTimeA);
+
+			// Send trade info to AT
+			byte[] messageData = BTCACCT.buildTradeMessage(partner.getAddress(), bitcoinPublicKeyHash, hashOfSecretA, lockTimeA, lockTimeB);
+			MessageTransaction messageTransaction = sendMessage(repository, tradeAccount, messageData, atAddress);
+
+			Block postDeploymentBlock = BlockUtils.mintBlock(repository);
+			int postDeploymentBlockHeight = postDeploymentBlock.getBlockData().getHeight();
+
+			long deployAtFee = deployAtTransaction.getTransactionData().getFee();
+			long deployersPostDeploymentBalance = deployersInitialBalance - fundingAmount - deployAtFee;
+
+			describeAt(repository, atAddress);
+
+			ATData atData = repository.getATRepository().fromATAddress(atAddress);
+			CrossChainTradeData tradeData = BTCACCT.populateTradeData(repository, atData);
+
+			// AT should be in TRADE mode
+			assertEquals(BTCACCT.Mode.TRADING, tradeData.mode);
+
+			// Check hashOfSecretA was extracted correctly
+			assertTrue(Arrays.equals(hashOfSecretA, tradeData.hashOfSecretA));
+
+			// Check trade partner Qortal address was extracted correctly
+			assertEquals(partner.getAddress(), tradeData.qortalPartnerAddress);
+
+			// Check trade partner's Bitcoin PKH was extracted correctly
+			assertTrue(Arrays.equals(bitcoinPublicKeyHash, tradeData.partnerBitcoinPKH));
+
+			// Test orphaning
+			BlockUtils.orphanToBlock(repository, postDeploymentBlockHeight);
+
+			// Check balances
+			long expectedBalance = deployersPostDeploymentBalance;
+			long actualBalance = deployer.getConfirmedBalance(Asset.QORT);
+
+			assertEquals("Deployer's post-orphan/pre-refund balance incorrect", expectedBalance, actualBalance);
+		}
+	}
+
+	// TEST SENDING TRADING INFO BUT NOT FROM AT CREATOR (SHOULD BE IGNORED)
 	@SuppressWarnings("unused")
 	@Test
 	public void testIncorrectTradeSender() throws DataException {
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			PrivateKeyAccount deployer = Common.getTestAccount(repository, "chloe");
-			PrivateKeyAccount recipient = Common.getTestAccount(repository, "dilbert");
+			PrivateKeyAccount tradeAccount = createTradeAccount(repository);
+
+			PrivateKeyAccount partner = Common.getTestAccount(repository, "dilbert");
+
 			PrivateKeyAccount bystander = Common.getTestAccount(repository, "bob");
 
 			long deployersInitialBalance = deployer.getConfirmedBalance(Asset.QORT);
-			long recipientsInitialBalance = recipient.getConfirmedBalance(Asset.QORT);
+			long partnersInitialBalance = partner.getConfirmedBalance(Asset.QORT);
 
-			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer);
+			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer, tradeAccount.getAddress());
 			Account at = deployAtTransaction.getATAccount();
 			String atAddress = at.getAddress();
 
-			// Send recipient's address to AT BUT NOT FROM AT CREATOR
-			byte[] recipientAddressBytes = Bytes.ensureCapacity(Base58.decode(recipient.getAddress()), 32, 0);
-			MessageTransaction messageTransaction = sendMessage(repository, bystander, recipientAddressBytes, atAddress);
+			long partnersOfferMessageTransactionTimestamp = System.currentTimeMillis();
+			int lockTimeA = calcTestLockTimeA(partnersOfferMessageTransactionTimestamp);
+			int lockTimeB = BTCACCT.calcLockTimeB(partnersOfferMessageTransactionTimestamp, lockTimeA);
+
+			// Send trade info to AT BUT NOT FROM AT CREATOR
+			byte[] messageData = BTCACCT.buildTradeMessage(partner.getAddress(), bitcoinPublicKeyHash, hashOfSecretA, lockTimeA, lockTimeB);
+			MessageTransaction messageTransaction = sendMessage(repository, bystander, messageData, atAddress);
 
-			// Initial payment should NOT happen
 			BlockUtils.mintBlock(repository);
 
-			long expectedBalance = recipientsInitialBalance;
-			long actualBalance = recipient.getConfirmedBalance(Asset.QORT);
+			long expectedBalance = partnersInitialBalance;
+			long actualBalance = partner.getConfirmedBalance(Asset.QORT);
 
-			assertEquals("Recipient's post-initial-payout balance incorrect", expectedBalance, actualBalance);
+			assertEquals("Partner's post-initial-payout balance incorrect", expectedBalance, actualBalance);
 
 			describeAt(repository, atAddress);
+
+			ATData atData = repository.getATRepository().fromATAddress(atAddress);
+			CrossChainTradeData tradeData = BTCACCT.populateTradeData(repository, atData);
+
+			// AT should still be in OFFER mode
+			assertEquals(BTCACCT.Mode.OFFERING, tradeData.mode);
 		}
 	}
 
@@ -230,34 +321,48 @@ public class AtTests extends Common {
 	public void testAutomaticTradeRefund() throws DataException {
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			PrivateKeyAccount deployer = Common.getTestAccount(repository, "chloe");
-			PrivateKeyAccount recipient = Common.getTestAccount(repository, "dilbert");
+			PrivateKeyAccount tradeAccount = createTradeAccount(repository);
+
+			PrivateKeyAccount partner = Common.getTestAccount(repository, "dilbert");
 
 			long deployersInitialBalance = deployer.getConfirmedBalance(Asset.QORT);
-			long recipientsInitialBalance = recipient.getConfirmedBalance(Asset.QORT);
+			long partnersInitialBalance = partner.getConfirmedBalance(Asset.QORT);
 
-			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer);
+			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer, tradeAccount.getAddress());
 			Account at = deployAtTransaction.getATAccount();
 			String atAddress = at.getAddress();
 
-			// Send recipient's address to AT
-			byte[] recipientAddressBytes = Bytes.ensureCapacity(Base58.decode(recipient.getAddress()), 32, 0);
-			MessageTransaction messageTransaction = sendMessage(repository, deployer, recipientAddressBytes, atAddress);
+			long partnersOfferMessageTransactionTimestamp = System.currentTimeMillis();
+			int lockTimeA = calcTestLockTimeA(partnersOfferMessageTransactionTimestamp);
+			int lockTimeB = BTCACCT.calcLockTimeB(partnersOfferMessageTransactionTimestamp, lockTimeA);
 
-			// Initial payment should happen 1st block after receiving recipient address
-			BlockUtils.mintBlock(repository);
+			// Send trade info to AT
+			byte[] messageData = BTCACCT.buildTradeMessage(partner.getAddress(), bitcoinPublicKeyHash, hashOfSecretA, lockTimeA, lockTimeB);
+			MessageTransaction messageTransaction = sendMessage(repository, tradeAccount, messageData, atAddress);
 
+			Block postDeploymentBlock = BlockUtils.mintBlock(repository);
+			int postDeploymentBlockHeight = postDeploymentBlock.getBlockData().getHeight();
+
+			// Check refund
 			long deployAtFee = deployAtTransaction.getTransactionData().getFee();
-			long messageFee = messageTransaction.getTransactionData().getFee();
-			long deployersPostDeploymentBalance = deployersInitialBalance - fundingAmount - deployAtFee - messageFee;
+			long deployersPostDeploymentBalance = deployersInitialBalance - fundingAmount - deployAtFee;
 
 			checkTradeRefund(repository, deployer, deployersInitialBalance, deployAtFee);
 
 			describeAt(repository, atAddress);
 
-			// Test orphaning
-			BlockUtils.orphanLastBlock(repository);
-			BlockUtils.orphanLastBlock(repository);
+			// Check AT is finished
+			ATData atData = repository.getATRepository().fromATAddress(atAddress);
+			assertTrue(atData.getIsFinished());
 
+			// AT should be in REFUNDED mode
+			CrossChainTradeData tradeData = BTCACCT.populateTradeData(repository, atData);
+			assertEquals(BTCACCT.Mode.REFUNDED, tradeData.mode);
+
+			// Test orphaning
+			BlockUtils.orphanToBlock(repository, postDeploymentBlockHeight);
+
+			// Check balances
 			long expectedBalance = deployersPostDeploymentBalance;
 			long actualBalance = deployer.getConfirmedBalance(Asset.QORT);
 
@@ -267,46 +372,63 @@ public class AtTests extends Common {
 
 	@SuppressWarnings("unused")
 	@Test
-	public void testCorrectSecretCorrectSender() throws DataException {
+	public void testCorrectSecretsCorrectSender() throws DataException {
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			PrivateKeyAccount deployer = Common.getTestAccount(repository, "chloe");
-			PrivateKeyAccount recipient = Common.getTestAccount(repository, "dilbert");
+			PrivateKeyAccount tradeAccount = createTradeAccount(repository);
+
+			PrivateKeyAccount partner = Common.getTestAccount(repository, "dilbert");
 
 			long deployersInitialBalance = deployer.getConfirmedBalance(Asset.QORT);
-			long recipientsInitialBalance = recipient.getConfirmedBalance(Asset.QORT);
+			long partnersInitialBalance = partner.getConfirmedBalance(Asset.QORT);
 
-			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer);
+			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer, tradeAccount.getAddress());
 			Account at = deployAtTransaction.getATAccount();
 			String atAddress = at.getAddress();
 
-			// Send recipient's address to AT
-			byte[] recipientAddressBytes = Bytes.ensureCapacity(Base58.decode(recipient.getAddress()), 32, 0);
-			MessageTransaction messageTransaction = sendMessage(repository, deployer, recipientAddressBytes, atAddress);
+			long partnersOfferMessageTransactionTimestamp = System.currentTimeMillis();
+			int lockTimeA = calcTestLockTimeA(partnersOfferMessageTransactionTimestamp);
+			int lockTimeB = BTCACCT.calcLockTimeB(partnersOfferMessageTransactionTimestamp, lockTimeA);
 
-			// Initial payment should happen 1st block after receiving recipient address
+			// Send trade info to AT
+			byte[] messageData = BTCACCT.buildTradeMessage(partner.getAddress(), bitcoinPublicKeyHash, hashOfSecretA, lockTimeA, lockTimeB);
+			MessageTransaction messageTransaction = sendMessage(repository, tradeAccount, messageData, atAddress);
+
+			// Give AT time to process message
 			BlockUtils.mintBlock(repository);
 
-			// Send correct secret to AT
-			messageTransaction = sendMessage(repository, recipient, secret, atAddress);
+			// Send correct secrets to AT, from correct account
+			messageData = BTCACCT.buildRedeemMessage(secretA, secretB, partner.getAddress());
+			messageTransaction = sendMessage(repository, partner, messageData, atAddress);
 
 			// AT should send funds in the next block
 			ATStateData preRedeemAtStateData = repository.getATRepository().getLatestATState(atAddress);
 			BlockUtils.mintBlock(repository);
 
-			long expectedBalance = recipientsInitialBalance + initialPayout - messageTransaction.getTransactionData().getFee() + redeemAmount;
-			long actualBalance = recipient.getConfirmedBalance(Asset.QORT);
-
-			assertEquals("Recipent's post-redeem balance incorrect", expectedBalance, actualBalance);
-
 			describeAt(repository, atAddress);
 
+			// Check AT is finished
+			ATData atData = repository.getATRepository().fromATAddress(atAddress);
+			assertTrue(atData.getIsFinished());
+
+			// AT should be in REDEEMED mode
+			CrossChainTradeData tradeData = BTCACCT.populateTradeData(repository, atData);
+			assertEquals(BTCACCT.Mode.REDEEMED, tradeData.mode);
+
+			// Check balances
+			long expectedBalance = partnersInitialBalance - messageTransaction.getTransactionData().getFee() + redeemAmount;
+			long actualBalance = partner.getConfirmedBalance(Asset.QORT);
+
+			assertEquals("Partner's post-redeem balance incorrect", expectedBalance, actualBalance);
+
 			// Orphan redeem
 			BlockUtils.orphanLastBlock(repository);
 
-			expectedBalance = recipientsInitialBalance + initialPayout - messageTransaction.getTransactionData().getFee();
-			actualBalance = recipient.getConfirmedBalance(Asset.QORT);
+			// Check balances
+			expectedBalance = partnersInitialBalance - messageTransaction.getTransactionData().getFee();
+			actualBalance = partner.getConfirmedBalance(Asset.QORT);
 
-			assertEquals("Recipent's post-orphan/pre-redeem balance incorrect", expectedBalance, actualBalance);
+			assertEquals("Partner's post-orphan/pre-redeem balance incorrect", expectedBalance, actualBalance);
 
 			// Check AT state
 			ATStateData postOrphanAtStateData = repository.getATRepository().getLatestATState(atAddress);
@@ -317,99 +439,206 @@ public class AtTests extends Common {
 
 	@SuppressWarnings("unused")
 	@Test
-	public void testCorrectSecretIncorrectSender() throws DataException {
+	public void testCorrectSecretsIncorrectSender() throws DataException {
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			PrivateKeyAccount deployer = Common.getTestAccount(repository, "chloe");
-			PrivateKeyAccount recipient = Common.getTestAccount(repository, "dilbert");
+			PrivateKeyAccount tradeAccount = createTradeAccount(repository);
+
+			PrivateKeyAccount partner = Common.getTestAccount(repository, "dilbert");
+
 			PrivateKeyAccount bystander = Common.getTestAccount(repository, "bob");
 
 			long deployersInitialBalance = deployer.getConfirmedBalance(Asset.QORT);
-			long recipientsInitialBalance = recipient.getConfirmedBalance(Asset.QORT);
+			long partnersInitialBalance = partner.getConfirmedBalance(Asset.QORT);
 
-			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer);
+			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer, tradeAccount.getAddress());
 			long deployAtFee = deployAtTransaction.getTransactionData().getFee();
 
 			Account at = deployAtTransaction.getATAccount();
 			String atAddress = at.getAddress();
 
-			// Send recipient's address to AT
-			byte[] recipientAddressBytes = Bytes.ensureCapacity(Base58.decode(recipient.getAddress()), 32, 0);
-			MessageTransaction messageTransaction = sendMessage(repository, deployer, recipientAddressBytes, atAddress);
+			long partnersOfferMessageTransactionTimestamp = System.currentTimeMillis();
+			int lockTimeA = calcTestLockTimeA(partnersOfferMessageTransactionTimestamp);
+			int lockTimeB = BTCACCT.calcLockTimeB(partnersOfferMessageTransactionTimestamp, lockTimeA);
 
-			// Initial payment should happen 1st block after receiving recipient address
+			// Send trade info to AT
+			byte[] messageData = BTCACCT.buildTradeMessage(partner.getAddress(), bitcoinPublicKeyHash, hashOfSecretA, lockTimeA, lockTimeB);
+			MessageTransaction messageTransaction = sendMessage(repository, tradeAccount, messageData, atAddress);
+
+			// Give AT time to process message
 			BlockUtils.mintBlock(repository);
 
-			// Send correct secret to AT, but from wrong account
-			messageTransaction = sendMessage(repository, bystander, secret, atAddress);
+			// Send correct secrets to AT, but from wrong account
+			messageData = BTCACCT.buildRedeemMessage(secretA, secretB, partner.getAddress());
+			messageTransaction = sendMessage(repository, bystander, messageData, atAddress);
 
 			// AT should NOT send funds in the next block
 			ATStateData preRedeemAtStateData = repository.getATRepository().getLatestATState(atAddress);
 			BlockUtils.mintBlock(repository);
 
-			long expectedBalance = recipientsInitialBalance + initialPayout;
-			long actualBalance = recipient.getConfirmedBalance(Asset.QORT);
-
-			assertEquals("Recipent's balance incorrect", expectedBalance, actualBalance);
-
 			describeAt(repository, atAddress);
 
+			// Check AT is NOT finished
+			ATData atData = repository.getATRepository().fromATAddress(atAddress);
+			assertFalse(atData.getIsFinished());
+
+			// AT should still be in TRADE mode
+			CrossChainTradeData tradeData = BTCACCT.populateTradeData(repository, atData);
+			assertEquals(BTCACCT.Mode.TRADING, tradeData.mode);
+
+			// Check balances
+			long expectedBalance = partnersInitialBalance;
+			long actualBalance = partner.getConfirmedBalance(Asset.QORT);
+
+			assertEquals("Partner's balance incorrect", expectedBalance, actualBalance);
+
+			// Check eventual refund
 			checkTradeRefund(repository, deployer, deployersInitialBalance, deployAtFee);
 		}
 	}
 
 	@SuppressWarnings("unused")
 	@Test
-	public void testIncorrectSecretCorrectSender() throws DataException {
+	public void testIncorrectSecretsCorrectSender() throws DataException {
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			PrivateKeyAccount deployer = Common.getTestAccount(repository, "chloe");
-			PrivateKeyAccount recipient = Common.getTestAccount(repository, "dilbert");
+			PrivateKeyAccount tradeAccount = createTradeAccount(repository);
+
+			PrivateKeyAccount partner = Common.getTestAccount(repository, "dilbert");
 
 			long deployersInitialBalance = deployer.getConfirmedBalance(Asset.QORT);
-			long recipientsInitialBalance = recipient.getConfirmedBalance(Asset.QORT);
+			long partnersInitialBalance = partner.getConfirmedBalance(Asset.QORT);
 
-			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer);
+			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer, tradeAccount.getAddress());
 			long deployAtFee = deployAtTransaction.getTransactionData().getFee();
 
 			Account at = deployAtTransaction.getATAccount();
 			String atAddress = at.getAddress();
 
-			// Send recipient's address to AT
-			byte[] recipientAddressBytes = Bytes.ensureCapacity(Base58.decode(recipient.getAddress()), 32, 0);
-			MessageTransaction messageTransaction = sendMessage(repository, deployer, recipientAddressBytes, atAddress);
+			long partnersOfferMessageTransactionTimestamp = System.currentTimeMillis();
+			int lockTimeA = calcTestLockTimeA(partnersOfferMessageTransactionTimestamp);
+			int lockTimeB = BTCACCT.calcLockTimeB(partnersOfferMessageTransactionTimestamp, lockTimeA);
 
-			// Initial payment should happen 1st block after receiving recipient address
+			// Send trade info to AT
+			byte[] messageData = BTCACCT.buildTradeMessage(partner.getAddress(), bitcoinPublicKeyHash, hashOfSecretA, lockTimeA, lockTimeB);
+			MessageTransaction messageTransaction = sendMessage(repository, tradeAccount, messageData, atAddress);
+
+			// Give AT time to process message
 			BlockUtils.mintBlock(repository);
 
-			// Send correct secret to AT, but from wrong account
-			byte[] wrongSecret = Crypto.digest(secret);
-			messageTransaction = sendMessage(repository, recipient, wrongSecret, atAddress);
+			// Send incorrect secrets to AT, from correct account
+			byte[] wrongSecret = new byte[32];
+			RANDOM.nextBytes(wrongSecret);
+			messageData = BTCACCT.buildRedeemMessage(wrongSecret, secretB, partner.getAddress());
+			messageTransaction = sendMessage(repository, partner, messageData, atAddress);
 
 			// AT should NOT send funds in the next block
 			ATStateData preRedeemAtStateData = repository.getATRepository().getLatestATState(atAddress);
 			BlockUtils.mintBlock(repository);
 
-			long expectedBalance = recipientsInitialBalance + initialPayout - messageTransaction.getTransactionData().getFee();
-			long actualBalance = recipient.getConfirmedBalance(Asset.QORT);
+			describeAt(repository, atAddress);
 
-			assertEquals("Recipent's balance incorrect", expectedBalance, actualBalance);
+			// Check AT is NOT finished
+			ATData atData = repository.getATRepository().fromATAddress(atAddress);
+			assertFalse(atData.getIsFinished());
+
+			// AT should still be in TRADE mode
+			CrossChainTradeData tradeData = BTCACCT.populateTradeData(repository, atData);
+			assertEquals(BTCACCT.Mode.TRADING, tradeData.mode);
+
+			long expectedBalance = partnersInitialBalance - messageTransaction.getTransactionData().getFee();
+			long actualBalance = partner.getConfirmedBalance(Asset.QORT);
+
+			assertEquals("Partner's balance incorrect", expectedBalance, actualBalance);
+
+			// Send incorrect secrets to AT, from correct account
+			messageData = BTCACCT.buildRedeemMessage(secretA, wrongSecret, partner.getAddress());
+			messageTransaction = sendMessage(repository, partner, messageData, atAddress);
+
+			// AT should NOT send funds in the next block
+			BlockUtils.mintBlock(repository);
 
 			describeAt(repository, atAddress);
 
+			// Check AT is NOT finished
+			atData = repository.getATRepository().fromATAddress(atAddress);
+			assertFalse(atData.getIsFinished());
+
+			// AT should still be in TRADE mode
+			tradeData = BTCACCT.populateTradeData(repository, atData);
+			assertEquals(BTCACCT.Mode.TRADING, tradeData.mode);
+
+			// Check balances
+			expectedBalance = partnersInitialBalance - messageTransaction.getTransactionData().getFee() * 2;
+			actualBalance = partner.getConfirmedBalance(Asset.QORT);
+
+			assertEquals("Partner's balance incorrect", expectedBalance, actualBalance);
+
+			// Check eventual refund
 			checkTradeRefund(repository, deployer, deployersInitialBalance, deployAtFee);
 		}
 	}
 
+	@SuppressWarnings("unused")
+	@Test
+	public void testCorrectSecretsCorrectSenderInvalidMessageLength() throws DataException {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			PrivateKeyAccount deployer = Common.getTestAccount(repository, "chloe");
+			PrivateKeyAccount tradeAccount = createTradeAccount(repository);
+
+			PrivateKeyAccount partner = Common.getTestAccount(repository, "dilbert");
+
+			long deployersInitialBalance = deployer.getConfirmedBalance(Asset.QORT);
+			long partnersInitialBalance = partner.getConfirmedBalance(Asset.QORT);
+
+			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer, tradeAccount.getAddress());
+			Account at = deployAtTransaction.getATAccount();
+			String atAddress = at.getAddress();
+
+			long partnersOfferMessageTransactionTimestamp = System.currentTimeMillis();
+			int lockTimeA = calcTestLockTimeA(partnersOfferMessageTransactionTimestamp);
+			int lockTimeB = BTCACCT.calcLockTimeB(partnersOfferMessageTransactionTimestamp, lockTimeA);
+
+			// Send trade info to AT
+			byte[] messageData = BTCACCT.buildTradeMessage(partner.getAddress(), bitcoinPublicKeyHash, hashOfSecretA, lockTimeA, lockTimeB);
+			MessageTransaction messageTransaction = sendMessage(repository, tradeAccount, messageData, atAddress);
+
+			// Give AT time to process message
+			BlockUtils.mintBlock(repository);
+
+			// Send correct secrets to AT, from correct account, but missing receive address, hence incorrect length
+			messageData = Bytes.concat(secretA, secretB);
+			messageTransaction = sendMessage(repository, partner, messageData, atAddress);
+
+			// AT should NOT send funds in the next block
+			ATStateData preRedeemAtStateData = repository.getATRepository().getLatestATState(atAddress);
+			BlockUtils.mintBlock(repository);
+
+			describeAt(repository, atAddress);
+
+			// Check AT is NOT finished
+			ATData atData = repository.getATRepository().fromATAddress(atAddress);
+			assertFalse(atData.getIsFinished());
+
+			// AT should be in TRADING mode
+			CrossChainTradeData tradeData = BTCACCT.populateTradeData(repository, atData);
+			assertEquals(BTCACCT.Mode.TRADING, tradeData.mode);
+		}
+	}
+
 	@SuppressWarnings("unused")
 	@Test
 	public void testDescribeDeployed() throws DataException {
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			PrivateKeyAccount deployer = Common.getTestAccount(repository, "chloe");
-			PrivateKeyAccount recipient = Common.getTestAccount(repository, "dilbert");
+			PrivateKeyAccount tradeAccount = createTradeAccount(repository);
+
+			PrivateKeyAccount partner = Common.getTestAccount(repository, "dilbert");
 
 			long deployersInitialBalance = deployer.getConfirmedBalance(Asset.QORT);
-			long recipientsInitialBalance = recipient.getConfirmedBalance(Asset.QORT);
+			long partnersInitialBalance = partner.getConfirmedBalance(Asset.QORT);
 
-			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer);
+			DeployAtTransaction deployAtTransaction = doDeploy(repository, deployer, tradeAccount.getAddress());
 
 			List<ATData> executableAts = repository.getATRepository().getAllExecutableATs();
 
@@ -433,8 +662,12 @@ public class AtTests extends Common {
 		}
 	}
 
-	private DeployAtTransaction doDeploy(Repository repository, PrivateKeyAccount deployer) throws DataException {
-		byte[] creationBytes = BTCACCT.buildQortalAT(deployer.getAddress(), secretHash, refundTimeout, initialPayout, redeemAmount, bitcoinAmount);
+	private int calcTestLockTimeA(long messageTimestamp) {
+		return (int) (messageTimestamp / 1000L + tradeTimeout * 60);
+	}
+
+	private DeployAtTransaction doDeploy(Repository repository, PrivateKeyAccount deployer, String tradeAddress) throws DataException {
+		byte[] creationBytes = BTCACCT.buildQortalAT(tradeAddress, bitcoinPublicKeyHash, hashOfSecretB, redeemAmount, bitcoinAmount, tradeTimeout);
 
 		long txTimestamp = System.currentTimeMillis();
 		byte[] lastReference = deployer.getLastReference();
@@ -493,6 +726,7 @@ public class AtTests extends Common {
 
 	private void checkTradeRefund(Repository repository, Account deployer, long deployersInitialBalance, long deployAtFee) throws DataException {
 		long deployersPostDeploymentBalance = deployersInitialBalance - fundingAmount - deployAtFee;
+		int refundTimeout = tradeTimeout * 3 / 4 + 1; // close enough
 
 		// AT should automatically refund deployer after 'refundTimeout' blocks
 		for (int blockCount = 0; blockCount <= refundTimeout; ++blockCount)
@@ -500,7 +734,7 @@ public class AtTests extends Common {
 
 		// We don't bother to exactly calculate QORT spent running AT for several blocks, but we do know the expected range
 		long expectedMinimumBalance = deployersPostDeploymentBalance;
-		long expectedMaximumBalance = deployersInitialBalance - deployAtFee - initialPayout;
+		long expectedMaximumBalance = deployersInitialBalance - deployAtFee;
 
 		long actualBalance = deployer.getConfirmedBalance(Asset.QORT);
 
@@ -516,40 +750,43 @@ public class AtTests extends Common {
 		int currentBlockHeight = repository.getBlockRepository().getBlockchainHeight();
 
 		System.out.print(String.format("%s:\n"
+				+ "\tmode: %s\n"
 				+ "\tcreator: %s,\n"
 				+ "\tcreation timestamp: %s,\n"
 				+ "\tcurrent balance: %s QORT,\n"
-				+ "\tHASH160 of secret: %s,\n"
-				+ "\tinitial payout: %s QORT,\n"
+				+ "\tis finished: %b,\n"
+				+ "\tHASH160 of secret-B: %s,\n"
 				+ "\tredeem payout: %s QORT,\n"
 				+ "\texpected bitcoin: %s BTC,\n"
-				+ "\ttrade timeout: %d minutes (from trade start),\n"
 				+ "\tcurrent block height: %d,\n",
 				tradeData.qortalAtAddress,
+				tradeData.mode.name(),
 				tradeData.qortalCreator,
 				epochMilliFormatter.apply(tradeData.creationTimestamp),
 				Amounts.prettyAmount(tradeData.qortBalance),
-				HashCode.fromBytes(tradeData.secretHash).toString().substring(0, 40),
-				Amounts.prettyAmount(tradeData.initialPayout),
-				Amounts.prettyAmount(tradeData.redeemPayout),
+				atData.getIsFinished(),
+				HashCode.fromBytes(tradeData.hashOfSecretB).toString().substring(0, 40),
+				Amounts.prettyAmount(tradeData.qortAmount),
 				Amounts.prettyAmount(tradeData.expectedBitcoin),
-				tradeData.tradeRefundTimeout,
 				currentBlockHeight));
 
-		// Are we in 'offer' or 'trade' stage?
-		if (tradeData.tradeRefundHeight == null) {
-			// Offer
-			System.out.println(String.format("\tstatus: 'offer mode'"));
-		} else {
-			// Trade
-			System.out.println(String.format("\tstatus: 'trade mode',\n"
-					+ "\ttrade timeout: block %d,\n"
-					+ "\tBitcoin P2SH nLockTime: %d (%s),\n"
-					+ "\ttrade recipient: %s",
+		if (tradeData.mode != BTCACCT.Mode.OFFERING && tradeData.mode != BTCACCT.Mode.CANCELLED) {
+			System.out.println(String.format("\trefund height: block %d,\n"
+					+ "\tHASH160 of secret-A: %s,\n"
+					+ "\tBitcoin P2SH-A nLockTime: %d (%s),\n"
+					+ "\tBitcoin P2SH-B nLockTime: %d (%s),\n"
+					+ "\ttrade partner: %s",
 					tradeData.tradeRefundHeight,
-					tradeData.lockTime, epochMilliFormatter.apply(tradeData.lockTime * 1000L),
-					tradeData.qortalRecipient));
+					HashCode.fromBytes(tradeData.hashOfSecretA).toString().substring(0, 40),
+					tradeData.lockTimeA, epochMilliFormatter.apply(tradeData.lockTimeA * 1000L),
+					tradeData.lockTimeB, epochMilliFormatter.apply(tradeData.lockTimeB * 1000L),
+					tradeData.qortalPartnerAddress));
 		}
 	}
 
+	private PrivateKeyAccount createTradeAccount(Repository repository) {
+		// We actually use a known test account with funds to avoid PoW compute
+		return Common.getTestAccount(repository, "alice");
+	}
+
 }

src/test/java/org/qortal/test/btcacct/BtcTests.java

@@ -5,12 +5,13 @@ import static org.junit.Assert.*;
 import java.util.Arrays;
 import java.util.List;
 
+import org.bitcoinj.core.Transaction;
 import org.bitcoinj.store.BlockStoreException;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.qortal.crosschain.BTC;
-import org.qortal.crosschain.BTCACCT;
+import org.qortal.crosschain.BTCP2SH;
 import org.qortal.repository.DataException;
 import org.qortal.test.common.Common;
 
@@ -55,11 +56,52 @@ public class BtcTests extends Common {
 
 		List<byte[]> rawTransactions = BTC.getInstance().getAddressTransactions(p2shAddress);
 
-		byte[] expectedSecret = AtTests.secret;
-		byte[] secret = BTCACCT.findP2shSecret(p2shAddress, rawTransactions);
+		byte[] expectedSecret = "This string is exactly 32 bytes!".getBytes();
+		byte[] secret = BTCP2SH.findP2shSecret(p2shAddress, rawTransactions);
 
 		assertNotNull(secret);
 		assertTrue("secret incorrect", Arrays.equals(expectedSecret, secret));
 	}
 
+	@Test
+	public void testBuildSpend() {
+		BTC btc = BTC.getInstance();
+
+		String xprv58 = "tprv8ZgxMBicQKsPdahhFSrCdvC1bsWyzHHZfTneTVqUXN6s1wEtZLwAkZXzFP6TYLg2aQMecZLXLre5bTVGajEB55L1HYJcawpdFG66STVAWPJ";
+
+		String recipient = "2N8WCg52ULCtDSMjkgVTm5mtPdCsUptkHWE";
+		long amount = 1000L;
+
+		Transaction transaction = btc.buildSpend(xprv58, recipient, amount);
+		assertNotNull(transaction);
+
+		// Check spent key caching doesn't affect outcome
+
+		transaction = btc.buildSpend(xprv58, recipient, amount);
+		assertNotNull(transaction);
+	}
+
+	@Test
+	public void testGetWalletBalance() {
+		BTC btc = BTC.getInstance();
+
+		String xprv58 = "tprv8ZgxMBicQKsPdahhFSrCdvC1bsWyzHHZfTneTVqUXN6s1wEtZLwAkZXzFP6TYLg2aQMecZLXLre5bTVGajEB55L1HYJcawpdFG66STVAWPJ";
+
+		Long balance = btc.getWalletBalance(xprv58);
+
+		assertNotNull(balance);
+
+		System.out.println(BTC.format(balance));
+
+		// Check spent key caching doesn't affect outcome
+
+		Long repeatBalance = btc.getWalletBalance(xprv58);
+
+		assertNotNull(repeatBalance);
+
+		System.out.println(BTC.format(repeatBalance));
+
+		assertEquals(balance, repeatBalance);
+	}
+
 }

src/test/java/org/qortal/test/btcacct/BuildP2SH.java

@@ -13,7 +13,7 @@ import org.bitcoinj.script.Script.ScriptType;
 import org.bouncycastle.jce.provider.BouncyCastleProvider;
 import org.qortal.controller.Controller;
 import org.qortal.crosschain.BTC;
-import org.qortal.crosschain.BTCACCT;
+import org.qortal.crosschain.BTCP2SH;
 import org.qortal.crypto.Crypto;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
@@ -98,12 +98,12 @@ public class BuildP2SH {
 			System.out.println(String.format("Bitcoin redeem amount: %s", bitcoinAmount.toPlainString()));
 
 			System.out.println(String.format("Redeem Bitcoin address: %s", redeemBitcoinAddress));
-			System.out.println(String.format("Redeem miner's fee: %s", BTC.FORMAT.format(bitcoinFee)));
+			System.out.println(String.format("Redeem miner's fee: %s", BTC.format(bitcoinFee)));
 
 			System.out.println(String.format("Redeem script lockTime: %s (%d)", LocalDateTime.ofInstant(Instant.ofEpochSecond(lockTime), ZoneOffset.UTC), lockTime));
 			System.out.println(String.format("Hash of secret: %s", HashCode.fromBytes(secretHash)));
 
-			byte[] redeemScriptBytes = BTCACCT.buildScript(refundBitcoinAddress.getHash(), lockTime, redeemBitcoinAddress.getHash(), secretHash);
+			byte[] redeemScriptBytes = BTCP2SH.buildScript(refundBitcoinAddress.getHash(), lockTime, redeemBitcoinAddress.getHash(), secretHash);
 			System.out.println(String.format("Redeem script: %s", HashCode.fromBytes(redeemScriptBytes)));
 
 			byte[] redeemScriptHash = Crypto.hash160(redeemScriptBytes);
@@ -115,7 +115,7 @@ public class BuildP2SH {
 
 			// Fund P2SH
 			System.out.println(String.format("\nYou need to fund %s with %s (includes redeem/refund fee of %s)",
-					p2shAddress.toString(), BTC.FORMAT.format(bitcoinAmount), BTC.FORMAT.format(bitcoinFee)));
+					p2shAddress.toString(), BTC.format(bitcoinAmount), BTC.format(bitcoinFee)));
 
 			System.out.println("Once this is done, responder should run Respond to check P2SH funding and create AT");
 		} catch (DataException e) {

src/test/java/org/qortal/test/btcacct/CheckP2SH.java

@@ -15,7 +15,7 @@ import org.bitcoinj.script.Script.ScriptType;
 import org.bouncycastle.jce.provider.BouncyCastleProvider;
 import org.qortal.controller.Controller;
 import org.qortal.crosschain.BTC;
-import org.qortal.crosschain.BTCACCT;
+import org.qortal.crosschain.BTCP2SH;
 import org.qortal.crypto.Crypto;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
@@ -106,14 +106,14 @@ public class CheckP2SH {
 			System.out.println(String.format("Bitcoin redeem amount: %s", bitcoinAmount.toPlainString()));
 
 			System.out.println(String.format("Redeem Bitcoin address: %s", refundBitcoinAddress));
-			System.out.println(String.format("Redeem miner's fee: %s", BTC.FORMAT.format(bitcoinFee)));
+			System.out.println(String.format("Redeem miner's fee: %s", BTC.format(bitcoinFee)));
 
 			System.out.println(String.format("Redeem script lockTime: %s (%d)", LocalDateTime.ofInstant(Instant.ofEpochSecond(lockTime), ZoneOffset.UTC), lockTime));
 			System.out.println(String.format("Hash of secret: %s", HashCode.fromBytes(secretHash)));
 
 			System.out.println(String.format("P2SH address: %s", p2shAddress));
 
-			byte[] redeemScriptBytes = BTCACCT.buildScript(refundBitcoinAddress.getHash(), lockTime, redeemBitcoinAddress.getHash(), secretHash);
+			byte[] redeemScriptBytes = BTCP2SH.buildScript(refundBitcoinAddress.getHash(), lockTime, redeemBitcoinAddress.getHash(), secretHash);
 			System.out.println(String.format("Redeem script: %s", HashCode.fromBytes(redeemScriptBytes)));
 
 			byte[] redeemScriptHash = Crypto.hash160(redeemScriptBytes);
@@ -135,12 +135,12 @@ public class CheckP2SH {
 				System.out.println(String.format("Too soon (%s) to redeem based on median block time %s", LocalDateTime.ofInstant(Instant.ofEpochMilli(now), ZoneOffset.UTC), LocalDateTime.ofInstant(Instant.ofEpochSecond(medianBlockTime), ZoneOffset.UTC)));
 
 			// Check P2SH is funded
-			Coin p2shBalance = BTC.getInstance().getBalance(p2shAddress.toString());
+			Long p2shBalance = BTC.getInstance().getBalance(p2shAddress.toString());
 			if (p2shBalance == null) {
 				System.err.println(String.format("Unable to check P2SH address %s balance", p2shAddress));
 				System.exit(2);
 			}
-			System.out.println(String.format("P2SH address %s balance: %s", p2shAddress, BTC.FORMAT.format(p2shBalance)));
+			System.out.println(String.format("P2SH address %s balance: %s", p2shAddress, BTC.format(p2shBalance)));
 
 			// Grab all P2SH funding transactions (just in case there are more than one)
 			List<TransactionOutput> fundingOutputs = BTC.getInstance().getUnspentOutputs(p2shAddress.toString());
@@ -152,7 +152,7 @@ public class CheckP2SH {
 			System.out.println(String.format("Found %d output%s for P2SH", fundingOutputs.size(), (fundingOutputs.size() != 1 ? "s" : "")));
 
 			for (TransactionOutput fundingOutput : fundingOutputs)
-				System.out.println(String.format("Output %s:%d amount %s", HashCode.fromBytes(fundingOutput.getParentTransactionHash().getBytes()), fundingOutput.getIndex(), BTC.FORMAT.format(fundingOutput.getValue())));
+				System.out.println(String.format("Output %s:%d amount %s", HashCode.fromBytes(fundingOutput.getParentTransactionHash().getBytes()), fundingOutput.getIndex(), BTC.format(fundingOutput.getValue())));
 
 			if (fundingOutputs.isEmpty()) {
 				System.err.println(String.format("Can't redeem spent/unfunded P2SH"));

src/test/java/org/qortal/test/btcacct/DeployAT.java

@@ -34,20 +34,20 @@ public class DeployAT {
 		if (error != null)
 			System.err.println(error);
 
-		System.err.println(String.format("usage: DeployAT <your Qortal PRIVATE key> <QORT amount> <BTC amount> <HASH160-of-secret> <initial QORT payout> <AT funding amount> <AT trade timeout>"));
+		System.err.println(String.format("usage: DeployAT <your Qortal PRIVATE key> <QORT amount> <BTC amount> <your Bitcoin PKH> <HASH160-of-secret> <AT funding amount> <trade-timeout>"));
 		System.err.println(String.format("example: DeployAT "
 				+ "AdTd9SUEYSdTW8mgK3Gu72K97bCHGdUwi2VvLNjUohot \\\n"
 				+ "\t80.4020 \\\n"
 				+ "\t0.00864200 \\\n"
+				+ "\t750b06757a2448b8a4abebaa6e4662833fd5ddbb \\\n"
 				+ "\tdaf59884b4d1aec8c1b17102530909ee43c0151a \\\n"
-				+ "\t0.0001 \\\n"
 				+ "\t123.456 \\\n"
-				+ "\t10"));
+				+ "\t10080"));
 		System.exit(1);
 	}
 
 	public static void main(String[] args) {
-		if (args.length != 8)
+		if (args.length != 7)
 			usage(null);
 
 		Security.insertProviderAt(new BouncyCastleProvider(), 0);
@@ -56,8 +56,8 @@ public class DeployAT {
 		byte[] refundPrivateKey = null;
 		long redeemAmount = 0;
 		long expectedBitcoin = 0;
+		byte[] bitcoinPublicKeyHash = null;
 		byte[] secretHash = null;
-		long initialPayout = 0;
 		long fundingAmount = 0;
 		int tradeTimeout = 0;
 
@@ -75,21 +75,21 @@ public class DeployAT {
 			if (expectedBitcoin <= 0)
 				usage("Expected BTC amount must be positive");
 
+			bitcoinPublicKeyHash = HashCode.fromString(args[argIndex++]).asBytes();
+			if (bitcoinPublicKeyHash.length != 20)
+				usage("Bitcoin PKH must be 20 bytes");
+
 			secretHash = HashCode.fromString(args[argIndex++]).asBytes();
 			if (secretHash.length != 20)
 				usage("Hash of secret must be 20 bytes");
 
-			initialPayout = Long.parseLong(args[argIndex++]);
-			if (initialPayout < 0)
-				usage("Initial QORT payout must be positive");
-
 			fundingAmount = Long.parseLong(args[argIndex++]);
 			if (fundingAmount <= redeemAmount)
 				usage("AT funding amount must be greater than QORT redeem amount");
 
 			tradeTimeout = Integer.parseInt(args[argIndex++]);
-			if (tradeTimeout < 10 || tradeTimeout > 50000)
-				usage("AT trade timeout should be between 10 and 50,000 minutes");
+			if (tradeTimeout < 60 || tradeTimeout > 50000)
+				usage("Trade timeout (minutes) must be between 60 and 50000");
 		} catch (IllegalArgumentException e) {
 			usage(String.format("Invalid argument %d: %s", argIndex, e.getMessage()));
 		}
@@ -114,7 +114,7 @@ public class DeployAT {
 			System.out.println(String.format("HASH160 of secret: %s", HashCode.fromBytes(secretHash)));
 
 			// Deploy AT
-			byte[] creationBytes = BTCACCT.buildQortalAT(refundAccount.getAddress(), secretHash, tradeTimeout, initialPayout, redeemAmount, expectedBitcoin);
+			byte[] creationBytes = BTCACCT.buildQortalAT(refundAccount.getAddress(), bitcoinPublicKeyHash, secretHash, redeemAmount, expectedBitcoin, tradeTimeout);
 			System.out.println("CIYAM AT creation bytes: " + HashCode.fromBytes(creationBytes).toString());
 
 			long txTimestamp = System.currentTimeMillis();

src/test/java/org/qortal/test/btcacct/ElectrumXTests.java

@@ -12,8 +12,8 @@ import org.bouncycastle.jce.provider.BouncyCastleProvider;
 import org.bouncycastle.jsse.provider.BouncyCastleJsseProvider;
 import org.junit.Test;
 import org.qortal.crosschain.ElectrumX;
+import org.qortal.crosschain.ElectrumX.UnspentOutput;
 import org.qortal.utils.BitTwiddling;
-import org.qortal.utils.Pair;
 
 import com.google.common.hash.HashCode;
 
@@ -61,7 +61,7 @@ public class ElectrumXTests {
 
 			// Timestamp(int) is at 4 + 32 + 32 = 68 bytes offset
 			int offset = 4 + 32 + 32;
-			int timestamp = BitTwiddling.fromLEBytes(blockHeader, offset);
+			int timestamp = BitTwiddling.intFromLEBytes(blockHeader, offset);
 			System.out.println(String.format("Block %d timestamp: %d", height + i, timestamp));
 		}
 	}
@@ -100,13 +100,13 @@ public class ElectrumXTests {
 
 		Address address = Address.fromString(TestNet3Params.get(), "2N4szZUfigj7fSBCEX4PaC8TVbC5EvidaVF");
 		byte[] script = ScriptBuilder.createOutputScript(address).getProgram();
-		List<Pair<byte[], Integer>> unspentOutputs = electrumX.getUnspentOutputs(script);
+		List<UnspentOutput> unspentOutputs = electrumX.getUnspentOutputs(script);
 
 		assertNotNull(unspentOutputs);
 		assertFalse(unspentOutputs.isEmpty());
 
-		for (Pair<byte[], Integer> unspentOutput : unspentOutputs)
-			System.out.println(String.format("TestNet address %s has unspent output at tx %s, output index %d", address, HashCode.fromBytes(unspentOutput.getA()).toString(), unspentOutput.getB()));
+		for (UnspentOutput unspentOutput : unspentOutputs)
+			System.out.println(String.format("TestNet address %s has unspent output at tx %s, output index %d", address, HashCode.fromBytes(unspentOutput.hash), unspentOutput.index));
 	}
 
 	@Test

src/test/java/org/qortal/test/btcacct/Redeem.java

@@ -18,7 +18,7 @@ import org.bitcoinj.script.Script.ScriptType;
 import org.bouncycastle.jce.provider.BouncyCastleProvider;
 import org.qortal.controller.Controller;
 import org.qortal.crosschain.BTC;
-import org.qortal.crosschain.BTCACCT;
+import org.qortal.crosschain.BTCP2SH;
 import org.qortal.crypto.Crypto;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
@@ -107,7 +107,7 @@ public class Redeem {
 			System.out.println("Confirm the following is correct based on the info you've given:");
 
 			System.out.println(String.format("Redeem PRIVATE key: %s", HashCode.fromBytes(redeemPrivateKey)));
-			System.out.println(String.format("Redeem miner's fee: %s", BTC.FORMAT.format(bitcoinFee)));
+			System.out.println(String.format("Redeem miner's fee: %s", BTC.format(bitcoinFee)));
 			System.out.println(String.format("Redeem script lockTime: %s (%d)", LocalDateTime.ofInstant(Instant.ofEpochSecond(lockTime), ZoneOffset.UTC), lockTime));
 
 			// New/derived info
@@ -121,7 +121,7 @@ public class Redeem {
 
 			System.out.println(String.format("P2SH address: %s", p2shAddress));
 
-			byte[] redeemScriptBytes = BTCACCT.buildScript(refundBitcoinAddress.getHash(), lockTime, redeemAddress.getHash(), secretHash);
+			byte[] redeemScriptBytes = BTCP2SH.buildScript(refundBitcoinAddress.getHash(), lockTime, redeemAddress.getHash(), secretHash);
 			System.out.println(String.format("Redeem script: %s", HashCode.fromBytes(redeemScriptBytes)));
 
 			byte[] redeemScriptHash = Crypto.hash160(redeemScriptBytes);
@@ -147,12 +147,12 @@ public class Redeem {
 			}
 
 			// Check P2SH is funded
-			Coin p2shBalance = BTC.getInstance().getBalance(p2shAddress.toString());
+			Long p2shBalance = BTC.getInstance().getBalance(p2shAddress.toString());
 			if (p2shBalance == null) {
 				System.err.println(String.format("Unable to check P2SH address %s balance", p2shAddress));
 				System.exit(2);
 			}
-			System.out.println(String.format("P2SH address %s balance: %s BTC", p2shAddress, p2shBalance.toPlainString()));
+			System.out.println(String.format("P2SH address %s balance: %s", p2shAddress, BTC.format(p2shBalance)));
 
 			// Grab all P2SH funding transactions (just in case there are more than one)
 			List<TransactionOutput> fundingOutputs = BTC.getInstance().getUnspentOutputs(p2shAddress.toString());
@@ -164,7 +164,7 @@ public class Redeem {
 			System.out.println(String.format("Found %d output%s for P2SH", fundingOutputs.size(), (fundingOutputs.size() != 1 ? "s" : "")));
 
 			for (TransactionOutput fundingOutput : fundingOutputs)
-				System.out.println(String.format("Output %s:%d amount %s", HashCode.fromBytes(fundingOutput.getParentTransactionHash().getBytes()), fundingOutput.getIndex(), BTC.FORMAT.format(fundingOutput.getValue())));
+				System.out.println(String.format("Output %s:%d amount %s", HashCode.fromBytes(fundingOutput.getParentTransactionHash().getBytes()), fundingOutput.getIndex(), BTC.format(fundingOutput.getValue())));
 
 			if (fundingOutputs.isEmpty()) {
 				System.err.println(String.format("Can't redeem spent/unfunded P2SH"));
@@ -179,10 +179,10 @@ public class Redeem {
 			for (TransactionOutput fundingOutput : fundingOutputs)
 				System.out.println(String.format("Using output %s:%d for redeem", HashCode.fromBytes(fundingOutput.getParentTransactionHash().getBytes()), fundingOutput.getIndex()));
 
-			Coin redeemAmount = p2shBalance.subtract(bitcoinFee);
-			System.out.println(String.format("Spending %s of output, with %s as mining fee", BTC.FORMAT.format(redeemAmount), BTC.FORMAT.format(bitcoinFee)));
+			Coin redeemAmount = Coin.valueOf(p2shBalance).subtract(bitcoinFee);
+			System.out.println(String.format("Spending %s of output, with %s as mining fee", BTC.format(redeemAmount), BTC.format(bitcoinFee)));
 
-			Transaction redeemTransaction = BTCACCT.buildRedeemTransaction(redeemAmount, redeemKey, fundingOutputs, redeemScriptBytes, secret);
+			Transaction redeemTransaction = BTCP2SH.buildRedeemTransaction(redeemAmount, redeemKey, fundingOutputs, redeemScriptBytes, secret, redeemAddress.getHash());
 
 			byte[] redeemBytes = redeemTransaction.bitcoinSerialize();
 

src/test/java/org/qortal/test/btcacct/Refund.java

@@ -18,7 +18,7 @@ import org.bitcoinj.script.Script.ScriptType;
 import org.bouncycastle.jce.provider.BouncyCastleProvider;
 import org.qortal.controller.Controller;
 import org.qortal.crosschain.BTC;
-import org.qortal.crosschain.BTCACCT;
+import org.qortal.crosschain.BTCP2SH;
 import org.qortal.crypto.Crypto;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
@@ -110,7 +110,7 @@ public class Refund {
 			System.out.println(String.format("Redeem Bitcoin address: %s", redeemBitcoinAddress));
 			System.out.println(String.format("Redeem script lockTime: %s (%d)", LocalDateTime.ofInstant(Instant.ofEpochSecond(lockTime), ZoneOffset.UTC), lockTime));
 			System.out.println(String.format("P2SH address: %s", p2shAddress));
-			System.out.println(String.format("Refund miner's fee: %s", BTC.FORMAT.format(bitcoinFee)));
+			System.out.println(String.format("Refund miner's fee: %s", BTC.format(bitcoinFee)));
 
 			// New/derived info
 
@@ -120,7 +120,7 @@ public class Refund {
 			Address refundAddress = Address.fromKey(params, refundKey, ScriptType.P2PKH);
 			System.out.println(String.format("Refund recipient (PKH): %s (%s)", refundAddress, HashCode.fromBytes(refundAddress.getHash())));
 
-			byte[] redeemScriptBytes = BTCACCT.buildScript(refundAddress.getHash(), lockTime, redeemBitcoinAddress.getHash(), secretHash);
+			byte[] redeemScriptBytes = BTCP2SH.buildScript(refundAddress.getHash(), lockTime, redeemBitcoinAddress.getHash(), secretHash);
 			System.out.println(String.format("Redeem script: %s", HashCode.fromBytes(redeemScriptBytes)));
 
 			byte[] redeemScriptHash = Crypto.hash160(redeemScriptBytes);
@@ -151,12 +151,12 @@ public class Refund {
 			}
 
 			// Check P2SH is funded
-			Coin p2shBalance = BTC.getInstance().getBalance(p2shAddress.toString());
+			Long p2shBalance = BTC.getInstance().getBalance(p2shAddress.toString());
 			if (p2shBalance == null) {
 				System.err.println(String.format("Unable to check P2SH address %s balance", p2shAddress));
 				System.exit(2);
 			}
-			System.out.println(String.format("P2SH address %s balance: %s BTC", p2shAddress, p2shBalance.toPlainString()));
+			System.out.println(String.format("P2SH address %s balance: %s", p2shAddress, BTC.format(p2shBalance)));
 
 			// Grab all P2SH funding transactions (just in case there are more than one)
 			List<TransactionOutput> fundingOutputs = BTC.getInstance().getUnspentOutputs(p2shAddress.toString());
@@ -168,7 +168,7 @@ public class Refund {
 			System.out.println(String.format("Found %d output%s for P2SH", fundingOutputs.size(), (fundingOutputs.size() != 1 ? "s" : "")));
 
 			for (TransactionOutput fundingOutput : fundingOutputs)
-				System.out.println(String.format("Output %s:%d amount %s", HashCode.fromBytes(fundingOutput.getParentTransactionHash().getBytes()), fundingOutput.getIndex(), BTC.FORMAT.format(fundingOutput.getValue())));
+				System.out.println(String.format("Output %s:%d amount %s", HashCode.fromBytes(fundingOutput.getParentTransactionHash().getBytes()), fundingOutput.getIndex(), BTC.format(fundingOutput.getValue())));
 
 			if (fundingOutputs.isEmpty()) {
 				System.err.println(String.format("Can't refund spent/unfunded P2SH"));
@@ -183,10 +183,10 @@ public class Refund {
 			for (TransactionOutput fundingOutput : fundingOutputs)
 				System.out.println(String.format("Using output %s:%d for redeem", HashCode.fromBytes(fundingOutput.getParentTransactionHash().getBytes()), fundingOutput.getIndex()));
 
-			Coin refundAmount = p2shBalance.subtract(bitcoinFee);
-			System.out.println(String.format("Spending %s of output, with %s as mining fee", BTC.FORMAT.format(refundAmount), BTC.FORMAT.format(bitcoinFee)));
+			Coin refundAmount = Coin.valueOf(p2shBalance).subtract(bitcoinFee);
+			System.out.println(String.format("Spending %s of output, with %s as mining fee", BTC.format(refundAmount), BTC.format(bitcoinFee)));
 
-			Transaction redeemTransaction = BTCACCT.buildRefundTransaction(refundAmount, refundKey, fundingOutputs, redeemScriptBytes, lockTime);
+			Transaction redeemTransaction = BTCP2SH.buildRefundTransaction(refundAmount, refundKey, fundingOutputs, redeemScriptBytes, lockTime);
 
 			byte[] redeemBytes = redeemTransaction.bitcoinSerialize();
 

src/test/java/org/qortal/test/common/AccountUtils.java

@@ -20,15 +20,19 @@ public class AccountUtils {
 	public static final int txGroupId = Group.NO_GROUP;
 	public static final long fee = 1L * Amounts.MULTIPLIER;
 
-	public static void pay(Repository repository, String sender, String recipient, long amount) throws DataException {
-		PrivateKeyAccount sendingAccount = Common.getTestAccount(repository, sender);
-		PrivateKeyAccount recipientAccount = Common.getTestAccount(repository, recipient);
+	public static void pay(Repository repository, String testSenderName, String testRecipientName, long amount) throws DataException {
+		PrivateKeyAccount sendingAccount = Common.getTestAccount(repository, testSenderName);
+		PrivateKeyAccount recipientAccount = Common.getTestAccount(repository, testRecipientName);
 
+		pay(repository, sendingAccount, recipientAccount.getAddress(), amount);
+	}
+
+	public static void pay(Repository repository, PrivateKeyAccount sendingAccount, String recipientAddress, long amount) throws DataException {
 		byte[] reference = sendingAccount.getLastReference();
 		long timestamp = repository.getTransactionRepository().fromSignature(reference).getTimestamp() + 1;
 
 		BaseTransactionData baseTransactionData = new BaseTransactionData(timestamp, txGroupId, reference, sendingAccount.getPublicKey(), fee, null);
-		TransactionData transactionData = new PaymentTransactionData(baseTransactionData, recipientAccount.getAddress(), amount);
+		TransactionData transactionData = new PaymentTransactionData(baseTransactionData, recipientAddress, amount);
 
 		TransactionUtils.signAndMint(repository, transactionData, sendingAccount);
 	}

tools/peer-heights

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+
+# Requires: 'qort' script in PATH, and 'jq' utility installed
+
+set -e
+
+# Any extra args passed to us are also passed to 'qort', just prior to '-p peers'
+qort $@ -p peers | \
+	jq -r 'def lpad($len):
+			tostring | ($len - length) as $l | (" " * $l)[:$l] + .;
+		.[] |
+			select(has("lastHeight")) |
+			"\(.address | lpad(22)) (\(.version)), height \(.lastHeight), sig: \(.lastBlockSignature[0:8]), ts \(.lastBlockTimestamp / 1e3 | strftime("%Y-%m-%d %H:%M:%S"))"'

tools/qort

@@ -0,0 +1,87 @@
+#!/usr/bin/env bash
+
+# default output post-processor
+postproc=cat
+
+# Qortal defaults
+port=12391
+example_host=node10.qortal.org
+
+# called-as name
+name="${0##*/}"
+
+while [ -n "$*" ]; do
+	case $1 in
+		-p)
+			shift
+			postproc="json_pp -f json -t json -json_opt utf8,pretty"
+			;;
+
+		[Dd][Ee][Ll][Ee][Tt][Ee])
+			shift
+			method="-X DELETE"
+			;;
+
+		-l)
+			shift
+			src="--interface localhost"
+			;;
+
+		-t)
+			shift
+			testnet=true
+			;;
+
+		-j)
+			shift
+			content_type="Content-Type: application/json"
+			;;
+
+		*)
+			break
+			;;
+	esac
+done
+	
+if [ "${name}" = "qort" ]; then
+	port=${testnet:+62391}
+	port=${port:-12391}
+	example_host=node10.qortal.org
+fi
+
+if [ -z "$*" ]; then
+	echo "usage: $name [-l] [-p] [-t] [DELETE] <url> [<post-data>]"
+	echo "-l: use localhost as source address"
+	echo "-p: pretty-print JSON output"
+	echo "-t: use testnet port"
+	echo "example (using localhost:${port}): $name -p blocks/last"
+	echo "example: $name -p http://${example_host}:${port}/blocks/last"
+	echo "example: BASE_URL=http://${example_host}:${port} $name -p blocks/last"
+	echo "example: BASE_URL=${example_host} $name -p blocks/last"
+	echo "example: $name -l DELETE peers/known"
+	exit
+fi
+
+url=$1
+shift
+
+if [ "${url:0:4}" != "http" ]; then
+	base_url=${BASE_URL-localhost:${port}}
+
+	if [ "${base_url:0:4}" != "http" ]; then
+	        base_url="http://${base_url}"
+	fi
+
+	if [ -n "${base_url/#*:[0-9[0-9]*}" ]; then
+	        base_url="${base_url%%/}:${port}"
+	fi
+
+	url="${base_url%%/}/${url#/}"
+fi
+
+if [ "$#" != 0 ]; then
+	data="--data"
+fi
+
+curl --silent --insecure --connect-timeout 5 ${content_type:+--header} "${content_type}" ${method} ${src} --url ${url} ${data} "$@" | ${postproc}
+echo

tools/tx.pl

@@ -0,0 +1,353 @@
+#!/usr/bin/env perl
+
+use JSON;
+use warnings;
+use strict;
+
+use Getopt::Std;
+use File::Basename;
+
+our %opt;
+getopts('dpst', \%opt);
+
+my $proc = basename($0);
+
+if (@ARGV < 1) {
+	print STDERR "usage: $proc [-d] [-p] [-s] [-t] <tx-type> <privkey> <values> [<key-value pairs>]\n";
+	print STDERR "-d: debug, -p: process (broadcast) transaction, -s: sign, -t: testnet\n";
+	print STDERR "example: $proc PAYMENT P22kW91AJfDNBj32nVii292hhfo5AgvUYPz5W12ExsjE QxxQZiK7LZBjmpGjRz1FAZSx9MJDCoaHqz 0.1\n";
+	print STDERR "example: $proc JOIN_GROUP X92h3hf9k20kBj32nVnoh3XT14o5AgvUYPz5W12ExsjE 3\n";
+	print STDERR "example: BASE_URL=node10.qortal.org $proc JOIN_GROUP CB2DW91AJfd47432nVnoh3XT14o5AgvUYPz5W12ExsjE 3\n";
+	print STDERR "example: $proc -p sign C4ifh827ffDNBj32nVnoh3XT14o5AgvUYPz5W12ExsjE 111jivxUwerRw...Fjtu\n";
+	print STDERR "for help: $proc all\n";
+	print STDERR "for help: $proc REGISTER_NAME\n";
+	exit 2;
+}
+
+our $BASE_URL = $ENV{BASE_URL} || $opt{t} ? 'http://localhost:62391' : 'http://localhost:12391';
+our $DEFAULT_FEE = 0.001;
+
+our %TRANSACTION_TYPES = (
+	payment => {
+		url => 'payments/pay',
+		required => [qw(recipient amount)],
+		key_name => 'senderPublicKey',
+	},
+	# groups
+	set_group => {
+		url => 'groups/setdefault',
+		required => [qw(defaultGroupId)],
+		key_name => 'creatorPublicKey',
+	},
+	create_group => {
+		url => 'groups/create',
+		required => [qw(groupName description isOpen approvalThreshold)],
+		key_name => 'creatorPublicKey',
+	},
+	update_group => {
+		url => 'groups/update',
+		required => [qw(groupId newOwner newDescription newIsOpen newApprovalThreshold)],
+		key_name => 'ownerPublicKey',
+	},
+	join_group => {
+		url => 'groups/join',
+		required => [qw(groupId)],
+		key_name => 'joinerPublicKey',
+	},
+	leave_group => {
+		url => 'groups/leave',
+		required => [qw(groupId)],
+		key_name => 'leaverPublicKey',
+	},
+	group_invite => {
+		url => 'groups/invite',
+		required => [qw(groupId invitee)],
+		key_name => 'adminPublicKey',
+	},
+	group_kick => {
+		url => 'groups/kick',
+		required => [qw(groupId member reason)],
+		key_name => 'adminPublicKey',
+	},
+	add_group_admin => {
+		url => 'groups/addadmin',
+		required => [qw(groupId member)],
+		key_name => 'ownerPublicKey',
+	},
+	group_approval => {
+		url => 'groups/approval',
+		required => [qw(pendingSignature approval)],
+		key_name => 'adminPublicKey',
+	},
+	# assets
+	issue_asset => {
+		url => 'assets/issue',
+		required => [qw(assetName description quantity isDivisible)],
+		key_name => 'issuerPublicKey',
+	},
+	update_asset => {
+		url => 'assets/update',
+		required => [qw(assetId newOwner)],
+		key_name => 'ownerPublicKey',
+	},
+	transfer_asset => {
+		url => 'assets/transfer',
+		required => [qw(recipient amount assetId)],
+		key_name => 'senderPublicKey',
+	},
+	create_order => {
+		url => 'assets/order',
+		required => [qw(haveAssetId wantAssetId amount price)],
+		key_name => 'creatorPublicKey',
+	},
+	# names
+	register_name => {
+		url => 'names/register',
+		required => [qw(name data)],
+		key_name => 'registrantPublicKey',
+	},
+	update_name => {
+		url => 'names/update',
+		required => [qw(newName newData)],
+		key_name => 'ownerPublicKey',
+	},
+	# reward-shares
+	reward_share => {
+		url => 'addresses/rewardshare',
+		required => [qw(recipient rewardSharePublicKey sharePercent)],
+		key_name => 'minterPublicKey',
+	},
+	# arbitrary
+	arbitrary => {
+		url => 'arbitrary',
+		required => [qw(service dataType data)],
+		key_name => 'senderPublicKey',
+	},
+	# chat
+	chat => {
+		url => 'chat',
+		required => [qw(data)],
+		optional => [qw(recipient isText isEncrypted)],
+		key_name => 'senderPublicKey',
+		defaults => { isText => 'true' },
+		pow_url => 'chat/compute',
+	},
+	# misc
+	publicize => {
+		url => 'addresses/publicize',
+		required => [],
+		key_name => 'senderPublicKey',
+		pow_url => 'addresses/publicize/compute',
+	},
+	# Cross-chain trading
+	build_trade => {
+		url => 'crosschain/build',
+		required => [qw(initialQortAmount finalQortAmount fundingQortAmount secretHash bitcoinAmount)],
+		optional => [qw(tradeTimeout)],
+		key_name => 'creatorPublicKey',
+		defaults => { tradeTimeout => 10800 },
+	},
+	trade_recipient => {
+		url => 'crosschain/tradeoffer/recipient',
+		required => [qw(atAddress recipient)],
+		key_name => 'creatorPublicKey',
+		remove => [qw(timestamp reference fee)],
+	},
+	trade_secret => {
+		url => 'crosschain/tradeoffer/secret',
+		required => [qw(atAddress secret)],
+		key_name => 'recipientPublicKey',
+		remove => [qw(timestamp reference fee)],
+	},
+	# These are fake transaction types to provide utility functions:
+	sign => {
+		url => 'transactions/sign',
+		required => [qw{transactionBytes}],
+	},
+);
+
+my $tx_type = lc(shift(@ARGV));
+
+if ($tx_type eq 'all') {
+	printf STDERR "Transaction types: %s\n", join(', ', sort { $a cmp $b } keys %TRANSACTION_TYPES);
+	exit 2;
+}
+
+my $tx_info = $TRANSACTION_TYPES{$tx_type};
+
+if (!$tx_info) {
+	printf STDERR "Transaction type '%s' unknown\n", uc($tx_type);
+	exit 1;
+}
+
+my @required = @{$tx_info->{required}};
+
+if (@ARGV < @required + 1) {
+	printf STDERR "usage: %s %s <privkey> %s", $proc, uc($tx_type), join(' ', map { "<$_>"} @required);
+	printf STDERR " %s", join(' ', map { "[$_ <$_>]" } @{$tx_info->{optional}}) if exists $tx_info->{optional};
+	print "\n";
+	exit 2;
+}
+
+my $priv_key = shift @ARGV;
+
+my $account = account($priv_key);
+my $raw;
+
+if ($tx_type ne 'sign') {
+	my %extras;
+
+	foreach my $required_arg (@required) {
+		$extras{$required_arg} = shift @ARGV;
+	}
+
+	# For CHAT we use a random reference
+	if ($tx_type eq 'chat') {
+		$extras{reference} = api('utils/random?length=64');
+	}
+
+	%extras = (%extras, %{$tx_info->{defaults}}) if exists $tx_info->{defaults};
+
+	%extras = (%extras, @ARGV);
+
+	$raw = build_raw($tx_type, $account, %extras);
+	printf "Raw: %s\n", $raw if $opt{d} || (!$opt{s} && !$opt{p});
+
+	# Some transaction types require proof-of-work, e.g. CHAT
+	if (exists $tx_info->{pow_url}) {
+		$raw = api($tx_info->{pow_url}, $raw);
+		printf "Raw with PoW: %s\n", $raw if $opt{d};
+	}
+} else {
+	$raw = shift @ARGV;
+	$opt{s}++;
+}
+
+if ($opt{s}) {
+	my $signed = sign($account->{private}, $raw);
+	printf "Signed: %s\n", $signed if $opt{d} || $tx_type eq 'sign';
+
+	if ($opt{p}) {
+		my $processed = process($signed);
+		printf "Processed: %s\n", $processed if $opt{d};
+	}
+
+	my $hex = api('utils/frombase58', $signed);
+	# sig is last 64 bytes / 128 chars
+	my $sighex = substr($hex, -128);
+
+	my $sig58 = api('utils/tobase58/{hex}', '', '{hex}', $sighex);
+	printf "Signature: %s\n", $sig58;
+}
+
+sub account {
+	my ($creator) = @_;
+
+	my $account = { private => $creator };
+	$account->{public} = api('utils/publickey', $creator);
+	$account->{address} = api('addresses/convert/{publickey}', '', '{publickey}', $account->{public});
+
+	return $account;
+}
+
+sub build_raw {
+	my ($type, $account, %extras) = @_;
+
+	my $tx_info = $TRANSACTION_TYPES{$type};
+	die("unknown tx type: $type\n") unless defined $tx_info;
+
+	my $ref = exists $extras{reference} ? $extras{reference} : lastref($account->{address});
+
+	my %json = (
+		timestamp => time * 1000,
+		reference => $ref,
+		fee => $DEFAULT_FEE,
+	);
+
+	$json{$tx_info->{key_name}} = $account->{public} if exists $tx_info->{key_name}; 
+
+	foreach my $required (@{$tx_info->{required}}) {
+		die("missing tx field: $required\n") unless exists $extras{$required};
+	}
+
+	while (my ($key, $value) = each %extras) {
+		$json{$key} = $value;
+	}
+
+	if (exists $tx_info->{remove}) {
+		foreach my $key (@{$tx_info->{remove}}) {
+			delete $json{$key};
+		}
+	}
+
+	my $json = "{\n";
+	while (my ($key, $value) = each %json) {
+		if (ref($value) eq 'ARRAY') {
+			$json .= "\t\"$key\": [],\n";
+		} else {
+			$json .= "\t\"$key\": \"$value\",\n";
+		}
+	}
+	# remove final comma
+	substr($json, -2, 1) = '';
+	$json .= "}\n";
+
+	printf "%s:\n%s\n", $type, $json if $opt{d};
+
+	my $raw = api($tx_info->{url}, $json);
+	return $raw;
+}
+
+sub sign {
+	my ($private, $raw) = @_;
+
+	my $json = <<"	__JSON__";
+	{
+		"privateKey": "$private",
+		"transactionBytes": "$raw"
+	}
+	__JSON__
+
+	return api('transactions/sign', $json);
+}
+
+sub process {
+	my ($signed) = @_;
+	
+	return api('transactions/process', $signed);
+}
+
+sub lastref {
+	my ($address) = @_;
+
+	return api('addresses/lastreference/{address}', '', '{address}', $address)
+}
+
+sub api {
+	my ($endpoint, $postdata, @args) = @_;
+
+	my $url = $endpoint;
+	my $method = 'GET';
+
+	for (my $i = 0; $i < @args; $i += 2) {
+		my $placemarker = $args[$i];
+		my $value = $args[$i + 1];
+		
+		$url =~ s/$placemarker/$value/g;
+	}
+
+	my $curl = "curl --silent --output - --url '$BASE_URL/$url'";
+	if (defined $postdata && $postdata ne '') {
+		$postdata =~ tr|\n| |s;
+		$curl .= " --header 'Content-Type: application/json' --data-binary '$postdata'";
+		$method = 'POST';
+	}
+	my $response = `$curl 2>/dev/null`; 
+	chomp $response;
+
+	if ($response eq '' || substr($response, 0, 6) eq '<html>' || $response =~ m/(^\{|,)"error":(\d+)[,}]/) {
+		die("API call '$method $BASE_URL/$endpoint' failed:\n$response\n");
+	}
+
+	return $response;
+}