Bump to v1.2.3

Various issues in Jetty v9.4.22 (and some later versions too)
cause websockets to use up all available threads.

Bumped Jetty to v9.4.29 to resolve some of these issues.

Changed some Qortal-side websocket code to minimize
locking on websocket notifiers. Websocket messages now
sent async, although the returned Futures are discarded,
as it's up to the remote end to consume fast enough.

Changed Controller to only request a SysTray update before
synchronization if there's a chance node might change height.
Similarly, Controller only requests SysTray update after
synchronization if chain tip has actually changed.
Both of the above together should reduce the number of
messages sent out via the admin status websockets.

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/1.3.4/AT-1.3.4.pom

@@ -3,7 +3,7 @@
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
   <modelVersion>4.0.0</modelVersion>
   <groupId>org.ciyam</groupId>
-  <artifactId>at</artifactId>
-  <version>1.0</version>
+  <artifactId>AT</artifactId>
+  <version>1.3.4</version>
   <description>POM was created from install:install-file</description>
 </project>

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

@@ -1,12 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <metadata>
   <groupId>org.ciyam</groupId>
-  <artifactId>at</artifactId>
+  <artifactId>AT</artifactId>
   <versioning>
-    <release>1.0</release>
+    <release>1.3.4</release>
     <versions>
-      <version>1.0</version>
+      <version>1.3.4</version>
     </versions>
-    <lastUpdated>20181105100741</lastUpdated>
+    <lastUpdated>20200414162728</lastUpdated>
   </versioning>
 </metadata>

log4j2.properties

@@ -1,11 +1,15 @@
 rootLogger.level = info
-# On Windows, uncomment this:
-# property.dirname = ${sys:user.home}\\AppData\\Roaming\\qortal\\
+# 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

pom.xml

@@ -3,12 +3,13 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>org.qortal</groupId>
 	<artifactId>qortal</artifactId>
-	<version>1.0.6</version>
+	<version>1.2.3</version>
 	<packaging>jar</packaging>
 	<properties>
-		<bitcoin.version>0.15.4</bitcoin.version>
+		<bitcoinj.version>0.15.5</bitcoinj.version>
 		<bouncycastle.version>1.64</bouncycastle.version>
 		<build.timestamp>${maven.build.timestamp}</build.timestamp>
+		<ciyam-at.version>1.3.4</ciyam-at.version>
 		<commons-net.version>3.6</commons-net.version>
 		<commons-text.version>1.8</commons-text.version>
 		<dagger.version>1.2.2</dagger.version>
@@ -16,7 +17,7 @@
 		<hsqldb.version>2.5.0-fixed</hsqldb.version>
 		<hsqldb-sqltool.version>2.5.0</hsqldb-sqltool.version>
 		<jersey.version>2.29.1</jersey.version>
-		<jetty.version>9.4.22.v20191022</jetty.version>
+		<jetty.version>9.4.29.v20200521</jetty.version>
 		<log4j.version>2.12.1</log4j.version>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 		<slf4j.version>1.7.12</slf4j.version>
@@ -405,14 +406,14 @@
 		<!-- CIYAM AT (automated transactions) -->
 		<dependency>
 			<groupId>org.ciyam</groupId>
-			<artifactId>at</artifactId>
-			<version>1.0</version>
+			<artifactId>AT</artifactId>
+			<version>${ciyam-at.version}</version>
 		</dependency>
 		<!-- Bitcoin support -->
 		<dependency>
 			<groupId>org.bitcoinj</groupId>
 			<artifactId>bitcoinj-core</artifactId>
-			<version>${bitcoin.version}</version>
+			<version>${bitcoinj.version}</version>
 		</dependency>
 		<!-- Utilities -->
 		<dependency>
@@ -450,6 +451,10 @@
 					<groupId>org.asynchttpclient</groupId>
 					<artifactId>async-http-client</artifactId>
 				</exclusion>
+				<exclusion>
+					<groupId>io.druid</groupId>
+					<artifactId>java-util</artifactId>
+				</exclusion>
 			</exclusions>
 		</dependency>
 		<!-- For NTP -->
@@ -503,6 +508,12 @@
 			<artifactId>mail</artifactId>
 			<version>1.5.0-b01</version>
 		</dependency>
+		<!-- Unicode homoglyph utilities -->
+		<dependency>
+			<groupId>net.codebox</groupId>
+			<artifactId>homoglyph</artifactId>
+			<version>1.2.0</version>
+		</dependency>
 		<!-- Jetty -->
 		<dependency>
 			<groupId>org.eclipse.jetty</groupId>
@@ -531,6 +542,12 @@
 			<artifactId>jetty-client</artifactId>
 			<version>${jetty.version}</version>
 		</dependency>
+		<!-- Websocket support -->
+		<dependency>
+			<groupId>org.eclipse.jetty.websocket</groupId>
+			<artifactId>javax-websocket-server-impl</artifactId>
+			<version>${jetty.version}</version>
+		</dependency>
 		<!-- Jersey -->
 		<dependency>
 			<groupId>org.glassfish.jersey.core</groupId>

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

@@ -1,7 +1,9 @@
 package org.qortal.account;
 
-import java.math.BigDecimal;
-import java.util.List;
+import static org.qortal.utils.Amounts.prettyAmount;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -9,12 +11,11 @@ import org.qortal.block.BlockChain;
 import org.qortal.data.account.AccountBalanceData;
 import org.qortal.data.account.AccountData;
 import org.qortal.data.account.RewardShareData;
-import org.qortal.data.transaction.TransactionData;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
-import org.qortal.transaction.Transaction;
 import org.qortal.utils.Base58;
 
+@XmlAccessorType(XmlAccessType.NONE) // Stops JAX-RS errors when unmarshalling blockchain config
 public class Account {
 
 	private static final Logger LOGGER = LogManager.getLogger(Account.class);
@@ -51,39 +52,52 @@ public class Account {
 		return new AccountData(this.address);
 	}
 
+	public void ensureAccount() throws DataException {
+		this.repository.getAccountRepository().ensureAccount(this.buildAccountData());
+	}
+
 	// Balance manipulations - assetId is 0 for QORT
 
-	public BigDecimal getBalance(long assetId) throws DataException {
+	public long getConfirmedBalance(long assetId) throws DataException {
 		AccountBalanceData accountBalanceData = this.repository.getAccountRepository().getBalance(this.address, assetId);
 		if (accountBalanceData == null)
-			return BigDecimal.ZERO.setScale(8);
+			return 0;
 
 		return accountBalanceData.getBalance();
 	}
 
-	public BigDecimal getConfirmedBalance(long assetId) throws DataException {
-		AccountBalanceData accountBalanceData = this.repository.getAccountRepository().getBalance(this.address, assetId);
-		if (accountBalanceData == null)
-			return BigDecimal.ZERO.setScale(8);
-
-		return accountBalanceData.getBalance();
-	}
-
-	public void setConfirmedBalance(long assetId, BigDecimal balance) throws DataException {
+	public void setConfirmedBalance(long assetId, long balance) throws DataException {
 		// Safety feature!
-		if (balance.compareTo(BigDecimal.ZERO) < 0) {
-			String message = String.format("Refusing to set negative balance %s [assetId %d] for %s", balance.toPlainString(), assetId, this.address);
+		if (balance < 0) {
+			String message = String.format("Refusing to set negative balance %s [assetId %d] for %s", prettyAmount(balance), assetId, this.address);
 			LOGGER.error(message);
 			throw new DataException(message);
 		}
 
+		// Delete account balance record instead of setting balance to zero
+		if (balance == 0) {
+			this.repository.getAccountRepository().delete(this.address, assetId);
+			return;
+		}
+
 		// Can't have a balance without an account - make sure it exists!
-		this.repository.getAccountRepository().ensureAccount(this.buildAccountData());
+		this.ensureAccount();
 
 		AccountBalanceData accountBalanceData = new AccountBalanceData(this.address, assetId, balance);
 		this.repository.getAccountRepository().save(accountBalanceData);
 
-		LOGGER.trace(() -> String.format("%s balance now %s [assetId %s]", this.address, balance.toPlainString(), assetId));
+		LOGGER.trace(() -> String.format("%s balance now %s [assetId %s]", this.address, prettyAmount(balance), assetId));
+	}
+
+	// Convenience method
+	public void modifyAssetBalance(long assetId, long deltaBalance) throws DataException {
+		this.repository.getAccountRepository().modifyAssetBalance(this.getAddress(), assetId, deltaBalance);
+
+		LOGGER.trace(() -> String.format("%s balance %s by %s [assetId %s]",
+				this.address,
+				(deltaBalance >= 0 ? "increased" : "decreased"),
+				prettyAmount(Math.abs(deltaBalance)),
+				assetId));
 	}
 
 	public void deleteBalance(long assetId) throws DataException {
@@ -99,38 +113,11 @@ public class Account {
 	 * @throws DataException
 	 */
 	public byte[] getLastReference() throws DataException {
-		byte[] reference = this.repository.getAccountRepository().getLastReference(this.address);
+		byte[] reference = AccountRefCache.getLastReference(this.repository, this.address);
 		LOGGER.trace(() -> String.format("Last reference for %s is %s", this.address, reference == null ? "null" : Base58.encode(reference)));
 		return reference;
 	}
 
-	/**
-	 * Fetch last reference for account, considering unconfirmed transactions only, or return null.
-	 * <p>
-	 * NOTE: calls Transaction.getUnconfirmedTransactions which discards uncommitted
-	 * repository changes.
-	 * 
-	 * @return byte[] reference, or null if no unconfirmed transactions for this account.
-	 * @throws DataException
-	 */
-	public byte[] getUnconfirmedLastReference() throws DataException {
-		// Newest unconfirmed transaction takes priority
-		List<TransactionData> unconfirmedTransactions = Transaction.getUnconfirmedTransactions(repository);
-
-		byte[] reference = null;
-
-		for (TransactionData transactionData : unconfirmedTransactions) {
-			String unconfirmedTransactionAddress = PublicKeyAccount.getAddress(transactionData.getCreatorPublicKey());
-
-			if (unconfirmedTransactionAddress.equals(this.address))
-				reference = transactionData.getSignature();
-		}
-
-		final byte[] loggingReference = reference;
-		LOGGER.trace(() -> String.format("Last unconfirmed reference for %s is %s", this.address, loggingReference == null ? "null" : Base58.encode(loggingReference)));
-		return reference;
-	}
-
 	/**
 	 * Set last reference for account.
 	 * 
@@ -143,7 +130,7 @@ public class Account {
 
 		AccountData accountData = this.buildAccountData();
 		accountData.setReference(reference);
-		this.repository.getAccountRepository().setLastReference(accountData);
+		AccountRefCache.setLastReference(this.repository, accountData);
 	}
 
 	// Default groupID manipulations
@@ -279,11 +266,7 @@ public class Account {
 		if (Account.isFounder(accountData.getFlags()))
 			return BlockChain.getInstance().getFounderEffectiveMintingLevel();
 
-		Integer level = accountData.getLevel();
-		if (level == null)
-			return 0;
-
-		return level;
+		return accountData.getLevel();
 	}
 
 	/**

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

@@ -0,0 +1,217 @@
+package org.qortal.account;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.function.BinaryOperator;
+
+import org.qortal.data.account.AccountData;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.utils.Pair;
+
+/**
+ * Account lastReference caching
+ * <p>
+ * When checking an account's lastReference, the value returned should be the
+ * most recent value set after processing the most recent block.
+ * <p>
+ * However, when processing a batch of transactions, e.g. during block processing or validation,
+ * each transaction needs to check, and maybe update, multiple accounts' lastReference values.
+ * <p>
+ * Because the intermediate updates would affect future checks, we set up a cache of that
+ * maintains a consistent value for fetching lastReference, but also tracks the latest new
+ * value, without the overhead of repository calls.
+ * <p>
+ * Thus, when batch transaction processing is finished, only the latest new lastReference values
+ * can be committed to the repository, via {@link AccountRefCache#commit()}.
+ * <p>
+ * Getting and setting lastReferences values are done the usual way via
+ * {@link Account#getLastReference()} and {@link Account#setLastReference(byte[])} which call
+ * package-visibility methods in <tt>AccountRefCache</tt>.
+ * <p>
+ * If {@link Account#getLastReference()} or {@link Account#setLastReference(byte[])} are called
+ * outside of caching then lastReference values are fetched/set directly from/to the repository.
+ * <p>
+ * <tt>AccountRefCache</tt> implements <tt>AutoCloseable</tt> for (typical) use in a try-with-resources block.
+ *
+ * @see Account#getLastReference()
+ * @see Account#setLastReference(byte[])
+ * @see org.qortal.block.Block#process()
+ */
+public class AccountRefCache implements AutoCloseable {
+
+	private static final Map<Repository, RefCache> CACHE = new HashMap<>();
+
+	private static class RefCache {
+		private final Map<String, byte[]> getLastReferenceValues = new HashMap<>();
+		private final Map<String, Pair<byte[], byte[]>> setLastReferenceValues = new HashMap<>();
+
+		/**
+		 * Function for merging publicKey from new data with old publicKey from map.
+		 * <p>
+		 * Last reference is <tt>A</tt> element in pair.<br>
+		 * Public key is <tt>B</tt> element in pair.
+		 */
+		private static final BinaryOperator<Pair<byte[], byte[]>> mergePublicKey = (oldPair,  newPair) -> {
+			// If passed new pair contains non-null publicKey, then we use that one in preference.
+			if (newPair.getB() == null)
+				// Otherwise, inherit publicKey from old map value.
+				newPair.setB(oldPair.getB());
+
+			// We always use new lastReference from new pair.
+			return newPair;
+		};
+
+
+		public byte[] getLastReference(Repository repository, String address) throws DataException {
+			synchronized (this.getLastReferenceValues) {
+				byte[] lastReference = getLastReferenceValues.get(address);
+				if (lastReference != null)
+					// address is present in map, lastReference not null
+					return lastReference;
+
+				// address is present in map, just lastReference is null
+				if (getLastReferenceValues.containsKey(address))
+					return null;
+
+				lastReference = repository.getAccountRepository().getLastReference(address);
+				this.getLastReferenceValues.put(address, lastReference);
+				return lastReference;
+			}
+		}
+
+		public void setLastReference(AccountData accountData) {
+			// We're only interested in lastReference and publicKey
+			Pair<byte[], byte[]> newPair = new Pair<>(accountData.getReference(), accountData.getPublicKey());
+
+			synchronized (this.setLastReferenceValues) {
+				setLastReferenceValues.merge(accountData.getAddress(), newPair, mergePublicKey);
+			}
+		}
+
+		Map<String, Pair<byte[], byte[]>> getNewLastReferences() {
+			return setLastReferenceValues;
+		}
+	}
+
+	private Repository repository;
+
+	/**
+	 * Constructs a new account reference cache, unique to passed <tt>repository</tt> handle.
+	 * 
+	 * @param repository
+	 * @throws IllegalStateException if a cache already exists for <tt>repository</tt>
+	 */
+	public AccountRefCache(Repository repository) {
+		RefCache refCache = new RefCache();
+
+		synchronized (CACHE) {
+			if (CACHE.putIfAbsent(repository, refCache) != null)
+				throw new IllegalStateException("Account reference cache entry already exists");
+		}
+
+		this.repository = repository;
+	}
+
+	/**
+	 * Save all cached setLastReference account-reference values into repository.
+	 * <p>
+	 * Closes cache to prevent any future setLastReference() attempts post-commit.
+	 * 
+	 * @throws DataException
+	 */
+	public void commit() throws DataException {
+		RefCache refCache;
+
+		// Also duplicated in close(), this prevents future setLastReference() attempts post-commit.
+		synchronized (CACHE) {
+			refCache = CACHE.remove(this.repository);
+		}
+
+		if (refCache == null)
+			throw new IllegalStateException("Tried to commit non-existent account reference cache");
+
+		Map<String, Pair<byte[], byte[]>> newLastReferenceValues = refCache.getNewLastReferences();
+
+		for (Entry<String, Pair<byte[], byte[]>> entry : newLastReferenceValues.entrySet()) {
+			AccountData accountData = new AccountData(entry.getKey());
+
+			accountData.setReference(entry.getValue().getA());
+
+			if (entry.getValue().getB() != null)
+				accountData.setPublicKey(entry.getValue().getB());
+
+			this.repository.getAccountRepository().setLastReference(accountData);
+		}
+	}
+
+	@Override
+	public void close() {
+		synchronized (CACHE) {
+			CACHE.remove(this.repository);
+		}
+	}
+
+	/**
+	 * Returns lastReference value for account.
+	 * <p>
+	 * If cache is not in effect for passed <tt>repository</tt> handle,
+	 * then this method fetches lastReference directly from repository.
+	 * <p>
+	 * If cache <i>is</i> in effect, then this method returns cached
+	 * lastReference, which is <b>not</b> affected by calls to
+	 * <tt>setLastReference</tt>.
+	 * <p>
+	 * Typically called by corresponding method in Account class.
+	 * 
+	 * @param repository
+	 * @param address account's address
+	 * @return account's lastReference, or null if account unknown, or lastReference not set
+	 * @throws DataException
+	 */
+	/*package*/ static byte[] getLastReference(Repository repository, String address) throws DataException {
+		RefCache refCache;
+
+		synchronized (CACHE) {
+			refCache = CACHE.get(repository);
+		}
+
+		if (refCache == null)
+			return repository.getAccountRepository().getLastReference(address);
+
+		return refCache.getLastReference(repository, address);
+	}
+
+	/**
+	 * Sets lastReference value for account.
+	 * <p>
+	 * If cache is not in effect for passed <tt>repository</tt> handle,
+	 * then this method sets lastReference directly in repository.
+	 * <p>
+	 * If cache <i>is</i> in effect, then this method caches the new
+	 * lastReference, which is <b>not</b> returned by calls to
+	 * <tt>getLastReference</tt>.
+	 * <p>
+	 * Typically called by corresponding method in Account class.
+	 * 
+	 * @param repository
+	 * @param accountData
+	 * @throws DataException
+	 */
+	/*package*/ static void setLastReference(Repository repository, AccountData accountData) throws DataException {
+		RefCache refCache;
+
+		synchronized (CACHE) {
+			refCache = CACHE.get(repository);
+		}
+
+		if (refCache == null) {
+			repository.getAccountRepository().setLastReference(accountData);
+			return;
+		}
+
+		refCache.setLastReference(accountData);
+	}
+
+}

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

@@ -1,13 +0,0 @@
-package org.qortal.account;
-
-import org.qortal.repository.Repository;
-
-public final class GenesisAccount extends PublicKeyAccount {
-
-	public static final byte[] PUBLIC_KEY = new byte[] { 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
-
-	public GenesisAccount(Repository repository) {
-		super(repository, PUBLIC_KEY);
-	}
-
-}

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

@@ -0,0 +1,24 @@
+package org.qortal.account;
+
+import org.qortal.crypto.Crypto;
+import org.qortal.repository.Repository;
+
+public final class NullAccount extends PublicKeyAccount {
+
+	public static final byte[] PUBLIC_KEY = new byte[32];
+	public static final String ADDRESS = Crypto.toAddress(PUBLIC_KEY);
+
+	public NullAccount(Repository repository) {
+		super(repository, PUBLIC_KEY, ADDRESS);
+	}
+
+	protected NullAccount() {
+	}
+
+	@Override
+	public boolean verify(byte[] signature, byte[] message) {
+		// Can't sign, hence can't verify.
+		return false;
+	}
+
+}

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

@@ -2,18 +2,11 @@ package org.qortal.account;
 
 import org.bouncycastle.crypto.params.Ed25519PrivateKeyParameters;
 import org.bouncycastle.crypto.params.Ed25519PublicKeyParameters;
-import org.bouncycastle.crypto.params.X25519PrivateKeyParameters;
-import org.bouncycastle.crypto.params.X25519PublicKeyParameters;
-import org.bouncycastle.math.ec.rfc8032.Ed25519;
-import org.qortal.crypto.BouncyCastle25519;
 import org.qortal.crypto.Crypto;
 import org.qortal.repository.Repository;
 
 public class PrivateKeyAccount extends PublicKeyAccount {
 
-	private static final int SIGNATURE_LENGTH = 64;
-	private static final int SHARED_SECRET_LENGTH = 32;
-
 	private final byte[] privateKey;
 	private final Ed25519PrivateKeyParameters edPrivateKeyParams;
 
@@ -49,24 +42,11 @@ public class PrivateKeyAccount extends PublicKeyAccount {
 	}
 
 	public byte[] sign(byte[] message) {
-		byte[] signature = new byte[SIGNATURE_LENGTH];
-
-		this.edPrivateKeyParams.sign(Ed25519.Algorithm.Ed25519, edPublicKeyParams, null, message, 0, message.length, signature, 0);
-
-		return signature;
+		return Crypto.sign(this.edPrivateKeyParams, message);
 	}
 
 	public byte[] getSharedSecret(byte[] publicKey) {
-		byte[] x25519PrivateKey = BouncyCastle25519.toX25519PrivateKey(this.privateKey);
-		X25519PrivateKeyParameters xPrivateKeyParams = new X25519PrivateKeyParameters(x25519PrivateKey, 0);
-
-		byte[] x25519PublicKey = BouncyCastle25519.toX25519PublicKey(publicKey);
-		X25519PublicKeyParameters xPublicKeyParams = new X25519PublicKeyParameters(x25519PublicKey, 0);
-
-		byte[] sharedSecret = new byte[SHARED_SECRET_LENGTH];
-		xPrivateKeyParams.generateSecret(xPublicKeyParams, sharedSecret, 0);
-
-		return sharedSecret;
+		return Crypto.getSharedSecret(this.privateKey, publicKey);
 	}
 
 	public byte[] getRewardSharePrivateKey(byte[] publicKey) {

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

@@ -1,7 +1,6 @@
 package org.qortal.account;
 
 import org.bouncycastle.crypto.params.Ed25519PublicKeyParameters;
-import org.bouncycastle.math.ec.rfc8032.Ed25519;
 import org.qortal.crypto.Crypto;
 import org.qortal.data.account.AccountData;
 import org.qortal.repository.Repository;
@@ -22,6 +21,18 @@ public class PublicKeyAccount extends Account {
 		this.publicKey = edPublicKeyParams.getEncoded();
 	}
 
+	protected PublicKeyAccount(Repository repository, byte[] publicKey, String address) {
+		super(repository, address);
+
+		this.publicKey = publicKey;
+		this.edPublicKeyParams = null;
+	}
+
+	protected PublicKeyAccount() {
+		this.publicKey = null;
+		this.edPublicKeyParams = null;
+	}
+
 	public byte[] getPublicKey() {
 		return this.publicKey;
 	}
@@ -34,15 +45,7 @@ public class PublicKeyAccount extends Account {
 	}
 
 	public boolean verify(byte[] signature, byte[] message) {
-		return PublicKeyAccount.verify(this.publicKey, signature, message);
-	}
-
-	public static boolean verify(byte[] publicKey, byte[] signature, byte[] message) {
-		try {
-			return Ed25519.verify(signature, 0, publicKey, 0, message, 0, message.length);
-		} catch (Exception e) {
-			return false;
-		}
+		return Crypto.verify(this.publicKey, signature, message);
 	}
 
 	public static String getAddress(byte[] publicKey) {

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

@@ -0,0 +1,27 @@
+package org.qortal.api;
+
+import java.math.BigDecimal;
+
+import javax.xml.bind.annotation.adapters.XmlAdapter;
+
+import org.qortal.utils.Amounts;
+
+public class AmountTypeAdapter extends XmlAdapter<String, Long> {
+
+	@Override
+	public Long unmarshal(String input) throws Exception {
+		if (input == null)
+			return null;
+
+		return new BigDecimal(input).setScale(8).unscaledValue().longValue();
+	}
+
+	@Override
+	public String marshal(Long output) throws Exception {
+		if (output == null)
+			return null;
+
+		return Amounts.prettyAmount(output);
+	}
+
+}

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

@@ -5,6 +5,12 @@ 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.XmlRootElement;
+
+@XmlAccessorType(XmlAccessType.NONE)
+@XmlRootElement
 public enum ApiError {
 	// COMMON
 	// UNKNOWN(0, 500),
@@ -15,6 +21,7 @@ public enum ApiError {
 	REPOSITORY_ISSUE(5, 500),
 	NON_PRODUCTION(6, 403),
 	BLOCKCHAIN_NEEDS_SYNC(7, 503),
+	NO_TIME_SYNC(8, 503),
 
 	// VALIDATION
 	INVALID_SIGNATURE(101, 400),
@@ -117,7 +124,12 @@ public enum ApiError {
 	// MESSAGESIZE_EXCEEDED(1004, 400),
 
 	// Groups
-	GROUP_UNKNOWN(1101, 404);
+	GROUP_UNKNOWN(1101, 404),
+
+	// Bitcoin
+	BTC_NETWORK_ISSUE(1201, 500),
+	BTC_BALANCE_ISSUE(1202, 422),
+	BTC_TOO_SOON(1203, 422);
 
 	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/ApiErrorRoot.java

@@ -0,0 +1,20 @@
+package org.qortal.api;
+
+import javax.xml.bind.annotation.XmlElement;
+import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
+
+public class ApiErrorRoot {
+
+	private ApiError apiError;
+
+	@XmlJavaTypeAdapter(ApiErrorTypeAdapter.class)
+	@XmlElement(name = "error")
+	public ApiError getApiError() {
+		return this.apiError;
+	}
+
+	public void setApiError(ApiError apiError) {
+		this.apiError = apiError;
+	}
+
+}

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

@@ -0,0 +1,32 @@
+package org.qortal.api;
+
+import javax.xml.bind.annotation.adapters.XmlAdapter;
+
+public class ApiErrorTypeAdapter extends XmlAdapter<ApiErrorTypeAdapter.AdaptedApiError, ApiError> {
+
+	public static class AdaptedApiError {
+		public int code;
+		public String description;
+	}
+
+	@Override
+	public ApiError unmarshal(AdaptedApiError adaptedInput) throws Exception {
+		if (adaptedInput == null)
+			return null;
+
+		return ApiError.fromCode(adaptedInput.code);
+	}
+
+	@Override
+	public AdaptedApiError marshal(ApiError output) throws Exception {
+		if (output == null)
+			return null;
+
+		AdaptedApiError adaptedOutput = new AdaptedApiError();
+		adaptedOutput.code = output.getCode();
+		adaptedOutput.description = output.name();
+
+		return adaptedOutput;
+	}
+
+}

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

@@ -2,15 +2,31 @@ package org.qortal.api;
 
 import io.swagger.v3.jaxrs2.integration.resources.OpenApiResource;
 
+import java.io.InputStream;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.security.KeyStore;
+import java.security.SecureRandom;
 
+import javax.net.ssl.KeyManagerFactory;
+import javax.net.ssl.SSLContext;
+
+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.RequestLog;
 import org.eclipse.jetty.server.RequestLogWriter;
+import org.eclipse.jetty.server.SecureRequestCustomizer;
 import org.eclipse.jetty.server.Server;
+import org.eclipse.jetty.server.ServerConnector;
+import org.eclipse.jetty.server.SslConnectionFactory;
 import org.eclipse.jetty.server.handler.ErrorHandler;
 import org.eclipse.jetty.server.handler.InetAccessHandler;
 import org.eclipse.jetty.servlet.DefaultServlet;
@@ -18,10 +34,15 @@ import org.eclipse.jetty.servlet.FilterHolder;
 import org.eclipse.jetty.servlet.ServletContextHandler;
 import org.eclipse.jetty.servlet.ServletHolder;
 import org.eclipse.jetty.servlets.CrossOriginFilter;
+import org.eclipse.jetty.util.ssl.SslContextFactory;
 import org.glassfish.jersey.server.ResourceConfig;
 import org.glassfish.jersey.servlet.ServletContainer;
 import org.qortal.api.resource.AnnotationPostProcessor;
 import org.qortal.api.resource.ApiDefinition;
+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.settings.Settings;
 
 public class ApiService {
@@ -53,9 +74,57 @@ public class ApiService {
 	public void start() {
 		try {
 			// Create API server
-			InetAddress bindAddr = InetAddress.getByName(Settings.getInstance().getBindAddress());
-			InetSocketAddress endpoint = new InetSocketAddress(bindAddr, Settings.getInstance().getApiPort());
-			this.server = new Server(endpoint);
+
+			// SSL support if requested
+			String keystorePathname = Settings.getInstance().getSslKeystorePathname();
+			String keystorePassword = Settings.getInstance().getSslKeystorePassword();
+
+			if (keystorePathname != null && keystorePassword != null) {
+				// SSL version
+				if (!Files.isReadable(Path.of(keystorePathname)))
+					throw new RuntimeException("Failed to start SSL API due to broken keystore");
+
+				// BouncyCastle-specific SSLContext build
+				SSLContext sslContext = SSLContext.getInstance("TLS", "BCJSSE");
+				KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance("PKIX", "BCJSSE");
+
+				KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType(), "BC");
+
+				try (InputStream keystoreStream = Files.newInputStream(Paths.get(keystorePathname))) {
+					keyStore.load(keystoreStream, keystorePassword.toCharArray());
+				}
+
+				keyManagerFactory.init(keyStore, keystorePassword.toCharArray());
+				sslContext.init(keyManagerFactory.getKeyManagers(), null, new SecureRandom());
+
+				SslContextFactory.Server sslContextFactory = new SslContextFactory.Server();
+				sslContextFactory.setSslContext(sslContext);
+
+				this.server = new Server();
+
+				HttpConfiguration httpConfig = new HttpConfiguration();
+				httpConfig.setSecureScheme("https");
+				httpConfig.setSecurePort(Settings.getInstance().getApiPort());
+
+				SecureRequestCustomizer src = new SecureRequestCustomizer();
+				httpConfig.addCustomizer(src);
+
+				HttpConnectionFactory httpConnectionFactory = new HttpConnectionFactory(httpConfig);
+				SslConnectionFactory sslConnectionFactory = new SslConnectionFactory(sslContextFactory, HttpVersion.HTTP_1_1.asString());
+
+				ServerConnector portUnifiedConnector = new ServerConnector(this.server,
+						new DetectorConnectionFactory(sslConnectionFactory),
+						httpConnectionFactory);
+				portUnifiedConnector.setHost(Settings.getInstance().getBindAddress());
+				portUnifiedConnector.setPort(Settings.getInstance().getApiPort());
+
+				this.server.addConnector(portUnifiedConnector);
+			} else {
+				// Non-SSL
+				InetAddress bindAddr = InetAddress.getByName(Settings.getInstance().getBindAddress());
+				InetSocketAddress endpoint = new InetSocketAddress(bindAddr, Settings.getInstance().getApiPort());
+				this.server = new Server(endpoint);
+			}
 
 			// Error handler
 			ErrorHandler errorHandler = new ApiErrorHandler();
@@ -123,6 +192,11 @@ public class ApiService {
 				rewriteHandler.addRule(new RedirectPatternRule("/api-documentation", "/api-documentation/")); // redirect to add trailing slash if missing
 			}
 
+			context.addServlet(AdminStatusWebSocket.class, "/websockets/admin/status");
+			context.addServlet(BlocksWebSocket.class, "/websockets/blocks");
+			context.addServlet(ActiveChatsWebSocket.class, "/websockets/chat/active/*");
+			context.addServlet(ChatMessagesWebSocket.class, "/websockets/chat/messages");
+
 			// Start server
 			this.server.start();
 		} catch (Exception e) {

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

@@ -0,0 +1,25 @@
+package org.qortal.api;
+
+import java.math.BigDecimal;
+
+import javax.xml.bind.annotation.adapters.XmlAdapter;
+
+public class RewardSharePercentTypeAdapter extends XmlAdapter<String, Integer> {
+
+	@Override
+	public Integer unmarshal(String input) throws Exception {
+		if (input == null)
+			return null;
+
+		return new BigDecimal(input).setScale(2).unscaledValue().intValue();
+	}
+
+	@Override
+	public String marshal(Integer output) throws Exception {
+		if (output == null)
+			return null;
+
+		return String.format("%d.%02d", output / 100, Math.abs(output % 100));
+	}
+
+}

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

@@ -1,11 +1,10 @@
 package org.qortal.api.model;
 
-import java.math.BigDecimal;
-
 import javax.xml.bind.Marshaller;
 import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
 import javax.xml.bind.annotation.XmlElement;
+import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
 
 import org.qortal.data.asset.OrderData;
 
@@ -29,12 +28,14 @@ public class AggregatedOrder {
 	}
 
 	@XmlElement(name = "price")
-	public BigDecimal getPrice() {
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	public long getPrice() {
 		return this.orderData.getPrice();
 	}
 
 	@XmlElement(name = "unfulfilled")
-	public BigDecimal getUnfulfilled() {
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	public long getUnfulfilled() {
 		return this.orderData.getAmount();
 	}
 

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/BlockSignerSummary.java

@@ -6,7 +6,7 @@ import javax.xml.bind.annotation.XmlAccessorType;
 import org.qortal.crypto.Crypto;
 
 @XmlAccessorType(XmlAccessType.FIELD)
-public class BlockMinterSummary {
+public class BlockSignerSummary {
 
 	// Properties
 
@@ -20,19 +20,19 @@ public class BlockMinterSummary {
 
 	// Constructors
 
-	protected BlockMinterSummary() {
+	protected BlockSignerSummary() {
 	}
 
-	/** Constructs BlockMinterSummary in non-reward-share context. */
-	public BlockMinterSummary(byte[] blockMinterPublicKey, int blockCount) {
+	/** Constructs BlockSignerSummary in non-reward-share context. */
+	public BlockSignerSummary(byte[] blockMinterPublicKey, int blockCount) {
 		this.blockCount = blockCount;
 
 		this.mintingAccountPublicKey = blockMinterPublicKey;
 		this.mintingAccount = Crypto.toAddress(this.mintingAccountPublicKey);
 	}
 
-	/** Constructs BlockMinterSummary in reward-share context. */
-	public BlockMinterSummary(byte[] rewardSharePublicKey, int blockCount, byte[] mintingAccountPublicKey, String minterAccount, String recipientAccount) {
+	/** Constructs BlockSignerSummary in reward-share context. */
+	public BlockSignerSummary(byte[] rewardSharePublicKey, int blockCount, byte[] mintingAccountPublicKey, String minterAccount, String recipientAccount) {
 		this.rewardSharePublicKey = rewardSharePublicKey;
 		this.blockCount = blockCount;
 

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

@@ -25,7 +25,8 @@ public class ConnectedPeer {
 
 	public String address;
 	public String version;
-	public Long buildTimestamp;
+
+	public String nodeId;
 
 	public Integer lastHeight;
 	@Schema(example = "base58")
@@ -45,10 +46,9 @@ public class ConnectedPeer {
 		this.peersConnectedWhen = peer.getPeersConnectionTimestamp();
 
 		this.address = peerData.getAddress().toString();
-		if (peer.getVersionMessage() != null) {
-			this.version = peer.getVersionMessage().getVersionString();
-			this.buildTimestamp = peer.getVersionMessage().getBuildTimestamp();
-		}
+
+		this.version = peer.getPeersVersionString();
+		this.nodeId = peer.getPeersNodeId();
 
 		PeerChainTipData peerChainTipData = peer.getChainTipData();
 		if (peerChainTipData != null) {

src/main/java/org/qortal/api/model/CrossChainBitcoinP2SHStatus.java

@@ -0,0 +1,31 @@
+package org.qortal.api.model;
+
+import java.math.BigDecimal;
+
+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 CrossChainBitcoinP2SHStatus {
+
+	@Schema(description = "Bitcoin P2SH address", example = "3CdH27kTpV8dcFHVRYjQ8EEV5FJg9X8pSJ (mainnet), 2fMiRRXVsxhZeyfum9ifybZvaMHbQTmwdZw (testnet)")
+	public String bitcoinP2shAddress;
+
+	@Schema(description = "Bitcoin P2SH balance")
+	public BigDecimal bitcoinP2shBalance;
+
+	@Schema(description = "Can P2SH redeem yet?")
+	public boolean canRedeem;
+
+	@Schema(description = "Can P2SH refund yet?")
+	public boolean canRefund;
+
+	@Schema(description = "Secret extracted by P2SH redeemer")
+	public byte[] secret;
+
+	public CrossChainBitcoinP2SHStatus() {
+	}
+
+}

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

@@ -0,0 +1,31 @@
+package org.qortal.api.model;
+
+import java.math.BigDecimal;
+
+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 CrossChainBitcoinRedeemRequest {
+
+	@Schema(description = "Bitcoin HASH160(public key) for refund", example = "2nGDBPPPFS1c9w1h33YwFk4KUJU2")
+	public byte[] refundPublicKeyHash;
+
+	@Schema(description = "Bitcoin PRIVATE KEY for redeem", example = "cUvGNSnu14q6Hr1X7TESjYVTqBpFjj8GGLGjGdpJwD9NhSQKeYUk")
+	public byte[] redeemPrivateKey;
+
+	@Schema(description = "Qortal AT address")
+	public String atAddress;
+
+	@Schema(description = "Bitcoin miner fee", example = "0.00001000")
+	public BigDecimal bitcoinMinerFee;
+
+	@Schema(description = "32-byte secret", example = "6gVbAXCVzJXAWwtAVGAfgAkkXpeXvPUwSciPmCfSfXJG")
+	public byte[] secret;
+
+	public CrossChainBitcoinRedeemRequest() {
+	}
+
+}

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

@@ -0,0 +1,28 @@
+package org.qortal.api.model;
+
+import java.math.BigDecimal;
+
+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 CrossChainBitcoinRefundRequest {
+
+	@Schema(description = "Bitcoin PRIVATE KEY for refund", example = "cSP3zTb6bfm8GATtAcEJ8LqYtNQmzZ9jE2wQUVnZGiBzojDdrwKV")
+	public byte[] refundPrivateKey;
+
+	@Schema(description = "Bitcoin HASH160(public key) for redeem", example = "2daMveGc5pdjRyFacbxBzMksCbyC")
+	public byte[] redeemPublicKeyHash;
+
+	@Schema(description = "Qortal AT address")
+	public String atAddress;
+
+	@Schema(description = "Bitcoin miner fee", example = "0.00001000")
+	public BigDecimal bitcoinMinerFee;
+
+	public CrossChainBitcoinRefundRequest() {
+	}
+
+}

src/main/java/org/qortal/api/model/CrossChainBitcoinTemplateRequest.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 CrossChainBitcoinTemplateRequest {
+
+	@Schema(description = "Bitcoin HASH160(public key) for refund", example = "2nGDBPPPFS1c9w1h33YwFk4KUJU2")
+	public byte[] refundPublicKeyHash;
+
+	@Schema(description = "Bitcoin HASH160(public key) for redeem", example = "2daMveGc5pdjRyFacbxBzMksCbyC")
+	public byte[] redeemPublicKeyHash;
+
+	@Schema(description = "Qortal AT address")
+	public String atAddress;
+
+	public CrossChainBitcoinTemplateRequest() {
+	}
+
+}

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

@@ -0,0 +1,40 @@
+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 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;
+
+	@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 secret", example = "43vnftqkjxrhb5kJdkU1ZFQLEnWV")
+	public byte[] secretHash;
+
+	@Schema(description = "Bitcoin P2SH BTC balance for release of secret", example = "0.00864200")
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	public long bitcoinAmount;
+
+	@Schema(description = "Trade time window (minutes) from trade agreement to automatic refund", example = "10080")
+	public Integer tradeTimeout;
+
+	public CrossChainBuildRequest() {
+	}
+
+}

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

@@ -0,0 +1,20 @@
+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 CrossChainCancelRequest {
+
+	@Schema(description = "AT creator's public key", example = "C6wuddsBV3HzRrXUtezE7P5MoRXp5m3mEDokRDGZB6ry")
+	public byte[] creatorPublicKey;
+
+	@Schema(description = "Qortal AT address")
+	public String atAddress;
+
+	public CrossChainCancelRequest() {
+	}
+
+}

src/main/java/org/qortal/api/model/CrossChainSecretRequest.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 CrossChainSecretRequest {
+
+	@Schema(description = "Public key to match AT's 'recipient'", example = "C6wuddsBV3HzRrXUtezE7P5MoRXp5m3mEDokRDGZB6ry")
+	public byte[] recipientPublicKey;
+
+	@Schema(description = "Qortal AT address")
+	public String atAddress;
+
+	@Schema(description = "32-byte secret", example = "6gVbAXCVzJXAWwtAVGAfgAkkXpeXvPUwSciPmCfSfXJG")
+	public byte[] secret;
+
+	public CrossChainSecretRequest() {
+	}
+
+}

src/main/java/org/qortal/api/model/CrossChainTradeRequest.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 CrossChainTradeRequest {
+
+	@Schema(description = "AT creator's public key", example = "C6wuddsBV3HzRrXUtezE7P5MoRXp5m3mEDokRDGZB6ry")
+	public byte[] creatorPublicKey;
+
+	@Schema(description = "Qortal AT address")
+	public String atAddress;
+
+	@Schema(description = "Qortal address for trade partner/recipient")
+	public String recipient;
+
+	public CrossChainTradeRequest() {
+	}
+
+}

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

@@ -10,6 +10,7 @@ public class NodeInfo {
 	public long uptime;
 	public String buildVersion;
 	public long buildTimestamp;
+	public String nodeId;
 
 	public NodeInfo() {
 	}

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

@@ -3,13 +3,34 @@ package org.qortal.api.model;
 import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
 
+import org.qortal.controller.Controller;
+import org.qortal.network.Network;
+
 @XmlAccessorType(XmlAccessType.FIELD)
 public class NodeStatus {
 
-	public boolean isMintingPossible;
-	public boolean isSynchronizing;
+	public final boolean isMintingPossible;
+	public final boolean isSynchronizing;
+
+	// Not always present
+	public final Integer syncPercent;
+
+	public final int numberOfConnections;
+
+	public final int height;
 
 	public NodeStatus() {
+		isMintingPossible = Controller.getInstance().isMintingPossible();
+		isSynchronizing = Controller.getInstance().isSynchronizing();
+
+		if (isSynchronizing)
+			syncPercent = Controller.getInstance().getSyncPercent();
+		else
+			syncPercent = null;
+
+		numberOfConnections = Network.getInstance().getHandshakedPeers().size();
+
+		height = Controller.getInstance().getChainHeight();
 	}
 
 }

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

@@ -28,6 +28,7 @@ import org.qortal.api.ApiError;
 import org.qortal.api.ApiErrors;
 import org.qortal.api.ApiException;
 import org.qortal.api.ApiExceptionFactory;
+import org.qortal.api.Security;
 import org.qortal.api.model.ApiOnlineAccount;
 import org.qortal.api.model.RewardShareKeyRequest;
 import org.qortal.asset.Asset;
@@ -36,18 +37,27 @@ import org.qortal.crypto.Crypto;
 import org.qortal.data.account.AccountData;
 import org.qortal.data.account.RewardShareData;
 import org.qortal.data.network.OnlineAccountData;
+import org.qortal.data.transaction.PublicizeTransactionData;
 import org.qortal.data.transaction.RewardShareTransactionData;
+import org.qortal.data.transaction.TransactionData;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
 import org.qortal.repository.RepositoryManager;
 import org.qortal.settings.Settings;
+import org.qortal.transaction.PublicizeTransaction;
 import org.qortal.transaction.Transaction;
+import org.qortal.transaction.Transaction.TransactionType;
 import org.qortal.transaction.Transaction.ValidationResult;
 import org.qortal.transform.TransformationException;
 import org.qortal.transform.Transformer;
+import org.qortal.transform.transaction.PublicizeTransactionTransformer;
 import org.qortal.transform.transaction.RewardShareTransactionTransformer;
+import org.qortal.transform.transaction.TransactionTransformer;
+import org.qortal.utils.Amounts;
 import org.qortal.utils.Base58;
 
+import com.google.common.primitives.Bytes;
+
 @Path("/addresses")
 @Tag(name = "Addresses")
 public class AddressesResource {
@@ -66,32 +76,18 @@ public class AddressesResource {
 			)
 		}
 	)
-	@ApiErrors({ApiError.INVALID_ADDRESS, ApiError.REPOSITORY_ISSUE})
+	@ApiErrors({ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN, ApiError.REPOSITORY_ISSUE})
 	public AccountData getAccountInfo(@PathParam("address") String address) {
 		if (!Crypto.isValidAddress(address))
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			AccountData accountData = repository.getAccountRepository().getAccount(address);
-
 			// Not found?
 			if (accountData == null)
-				accountData = new AccountData(address);
-			else {
-				// Unconfirmed transactions could update lastReference
-				Account account = new Account(repository, address);
-
-				// Use last reference based on unconfirmed transactions if possible
-				byte[] unconfirmedLastReference = account.getUnconfirmedLastReference();
-
-				if (unconfirmedLastReference != null)
-					// There are unconfirmed transactions so modify returned data
-					accountData.setReference(unconfirmedLastReference);
-			}
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.ADDRESS_UNKNOWN);
 
 			return accountData;
-		} catch (ApiException e) {
-			throw e;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -100,42 +96,37 @@ public class AddressesResource {
 	@GET
 	@Path("/lastreference/{address}")
 	@Operation(
-		summary = "Fetch reference for next transaction to be created by address, considering unconfirmed transactions",
-		description = "Returns the base58-encoded signature of the last confirmed/unconfirmed transaction created by address, failing that: the first incoming transaction. Returns \"false\" if there is no transactions.",
+		summary = "Fetch reference for next transaction to be created by address",
+		description = "Returns the base58-encoded signature of the last confirmed transaction created by address, failing that: the first incoming transaction. Returns \"false\" if there is no last-reference.",
 		responses = {
 			@ApiResponse(
-				description = "the base58-encoded transaction signature",
+				description = "the base58-encoded last-reference",
 				content = @Content(mediaType = MediaType.TEXT_PLAIN, schema = @Schema(type = "string"))
 			)
 		}
 	)
-	@ApiErrors({ApiError.INVALID_ADDRESS, ApiError.REPOSITORY_ISSUE})
-	public String getLastReferenceUnconfirmed(@PathParam("address") String address) {
+	@ApiErrors({ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN, ApiError.REPOSITORY_ISSUE})
+	public String getLastReference(@PathParam("address") String address) {
 		if (!Crypto.isValidAddress(address))
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
 
 		byte[] lastReference = null;
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			Account account = new Account(repository, address);
+			AccountData accountData = repository.getAccountRepository().getAccount(address);
+			// Not found?
+			if (accountData == null)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.ADDRESS_UNKNOWN);
 
-			// Use last reference based on unconfirmed transactions if possible
-			lastReference = account.getUnconfirmedLastReference();
-
-			if (lastReference == null)
-				// No unconfirmed transactions so fallback to using one save in account data
-				lastReference = account.getLastReference();
-		} catch (ApiException e) {
-			throw e;
+			lastReference = accountData.getReference();
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
 
-		if(lastReference == null || lastReference.length == 0) {
+		if (lastReference == null || lastReference.length == 0)
 			return "false";
-		} else {
-			return Base58.encode(lastReference);
-		}
+
+		return Base58.encode(lastReference);
 	}
 
 	@GET
@@ -214,7 +205,7 @@ public class AddressesResource {
 			else if (!repository.getAssetRepository().assetExists(assetId))
 				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ASSET_ID);
 
-			return account.getBalance(assetId);
+			return Amounts.toBigDecimal(account.getConfirmedBalance(assetId));
 		} catch (ApiException e) {
 			throw e;
 		} catch (DataException e) {
@@ -408,4 +399,119 @@ public class AddressesResource {
 		}
 	}
 
+	@POST
+	@Path("/publicize")
+	@Operation(
+		summary = "Build raw, unsigned, PUBLICIZE transaction",
+		requestBody = @RequestBody(
+			required = true,
+			content = @Content(
+				mediaType = MediaType.APPLICATION_JSON,
+				schema = @Schema(
+					implementation = PublicizeTransactionData.class
+				)
+			)
+		),
+		responses = {
+			@ApiResponse(
+				description = "raw, unsigned, PUBLICIZE transaction encoded in Base58",
+				content = @Content(
+					mediaType = MediaType.TEXT_PLAIN,
+					schema = @Schema(
+						type = "string"
+					)
+				)
+			)
+		}
+	)
+	@ApiErrors({ApiError.NON_PRODUCTION, ApiError.TRANSACTION_INVALID, ApiError.TRANSFORMATION_ERROR, ApiError.REPOSITORY_ISSUE})
+	public String publicize(PublicizeTransactionData transactionData) {
+		if (Settings.getInstance().isApiRestricted())
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.NON_PRODUCTION);
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			Transaction transaction = Transaction.fromData(repository, transactionData);
+
+			ValidationResult result = transaction.isValidUnconfirmed();
+			if (result != ValidationResult.OK && result != ValidationResult.INCORRECT_NONCE)
+				throw TransactionsResource.createTransactionInvalidException(request, result);
+
+			byte[] bytes = PublicizeTransactionTransformer.toBytes(transactionData);
+			return Base58.encode(bytes);
+		} catch (TransformationException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.TRANSFORMATION_ERROR, e);
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@POST
+	@Path("/publicize/compute")
+	@Operation(
+		summary = "Compute nonce for raw, unsigned PUBLICIZE transaction",
+		requestBody = @RequestBody(
+			required = true,
+			content = @Content(
+				mediaType = MediaType.TEXT_PLAIN,
+				schema = @Schema(
+					type = "string",
+					description = "raw, unsigned PUBLICIZE transaction in base58 encoding",
+					example = "raw transaction base58"
+				)
+			)
+		),
+		responses = {
+			@ApiResponse(
+				description = "raw, unsigned, PUBLICIZE transaction encoded in Base58",
+				content = @Content(
+					mediaType = MediaType.TEXT_PLAIN,
+					schema = @Schema(
+						type = "string"
+					)
+				)
+			)
+		}
+	)
+	@ApiErrors({ApiError.TRANSACTION_INVALID, ApiError.INVALID_DATA, ApiError.TRANSFORMATION_ERROR, ApiError.REPOSITORY_ISSUE})
+	public String computePublicize(String rawBytes58) {
+		Security.checkApiCallAllowed(request);
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			byte[] rawBytes = Base58.decode(rawBytes58);
+			// We're expecting unsigned transaction, so append empty signature prior to decoding
+			rawBytes = Bytes.concat(rawBytes, new byte[TransactionTransformer.SIGNATURE_LENGTH]);
+
+			TransactionData transactionData = TransactionTransformer.fromBytes(rawBytes);
+			if (transactionData == null)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_DATA);
+
+			if (transactionData.getType() != TransactionType.PUBLICIZE)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_DATA);
+
+			PublicizeTransaction publicizeTransaction = (PublicizeTransaction) Transaction.fromData(repository, transactionData);
+
+			// Quicker validity check first before we compute nonce
+			ValidationResult result = publicizeTransaction.isValid();
+			if (result != ValidationResult.OK && result != ValidationResult.INCORRECT_NONCE)
+				throw TransactionsResource.createTransactionInvalidException(request, result);
+
+			publicizeTransaction.computeNonce();
+
+			// Re-check, but ignores signature
+			result = publicizeTransaction.isValidUnconfirmed();
+			if (result != ValidationResult.OK)
+				throw TransactionsResource.createTransactionInvalidException(request, result);
+
+			// Strip zeroed signature
+			transactionData.setSignature(null);
+
+			byte[] bytes = PublicizeTransactionTransformer.toBytes(transactionData);
+			return Base58.encode(bytes);
+		} catch (TransformationException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.TRANSFORMATION_ERROR, e);
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
 }

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

@@ -117,6 +117,7 @@ public class AdminResource {
 		nodeInfo.uptime = System.currentTimeMillis() - Controller.startTime;
 		nodeInfo.buildVersion = Controller.getInstance().getVersionString();
 		nodeInfo.buildTimestamp = Controller.getInstance().getBuildTimestamp();
+		nodeInfo.nodeId = Network.getInstance().getOurNodeId();
 
 		return nodeInfo;
 	}
@@ -136,9 +137,6 @@ public class AdminResource {
 
 		NodeStatus nodeStatus = new NodeStatus();
 
-		nodeStatus.isMintingPossible = Controller.getInstance().isMintingPossible();
-		nodeStatus.isSynchronizing = Controller.getInstance().isSynchronizing();
-
 		return nodeStatus;
 	}
 
@@ -304,13 +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"
 				)
 			)
 		),
@@ -321,13 +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/ApiDefinition.java

@@ -13,7 +13,10 @@ import io.swagger.v3.oas.annotations.tags.Tag;
 			@Tag(name = "Admin"),
 			@Tag(name = "Arbitrary"),
 			@Tag(name = "Assets"),
+			@Tag(name = "Automated Transactions"),
 			@Tag(name = "Blocks"),
+			@Tag(name = "Chat"),
+			@Tag(name = "Cross-Chain"),
 			@Tag(name = "Groups"),
 			@Tag(name = "Names"),
 			@Tag(name = "Payments"),

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

@@ -0,0 +1,206 @@
+package org.qortal.api.resource;
+
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.Parameter;
+import io.swagger.v3.oas.annotations.media.ArraySchema;
+import io.swagger.v3.oas.annotations.media.Content;
+import io.swagger.v3.oas.annotations.media.Schema;
+import io.swagger.v3.oas.annotations.parameters.RequestBody;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.tags.Tag;
+
+import java.util.List;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.ws.rs.GET;
+import javax.ws.rs.POST;
+import javax.ws.rs.Path;
+import javax.ws.rs.PathParam;
+import javax.ws.rs.QueryParam;
+import javax.ws.rs.core.Context;
+import javax.ws.rs.core.MediaType;
+
+import org.ciyam.at.MachineState;
+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;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+import org.qortal.settings.Settings;
+import org.qortal.transaction.Transaction;
+import org.qortal.transaction.Transaction.ValidationResult;
+import org.qortal.transform.TransformationException;
+import org.qortal.transform.transaction.DeployAtTransactionTransformer;
+import org.qortal.utils.Base58;
+
+@Path("/at")
+@Tag(name = "Automated Transactions")
+public class AtResource {
+
+	@Context
+	HttpServletRequest request;
+
+	@GET
+	@Path("/byfunction/{codehash}")
+	@Operation(
+		summary = "Find automated transactions with matching functionality (code hash)",
+		responses = {
+			@ApiResponse(
+				description = "automated transactions",
+				content = @Content(
+					array = @ArraySchema(
+						schema = @Schema(
+							implementation = ATData.class
+						)
+					)
+				)
+			)
+		}
+	)
+	@ApiErrors({
+		ApiError.INVALID_CRITERIA, ApiError.REPOSITORY_ISSUE
+	})
+	public List<ATData> getByFunctionality(
+			@PathParam("codehash")
+			String codeHash58,
+			@Parameter(description = "whether to include ATs that can run, or not, or both (if omitted)")
+			@QueryParam("isExecutable")
+			Boolean isExecutable,
+			@Parameter( ref = "limit") @QueryParam("limit") Integer limit,
+			@Parameter( ref = "offset" ) @QueryParam("offset") Integer offset,
+			@Parameter( ref = "reverse" ) @QueryParam("reverse") Boolean reverse) {
+		// Decode codeHash
+		byte[] codeHash;
+		try {
+			codeHash = Base58.decode(codeHash58);
+		} catch (NumberFormatException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA, e);
+		}
+
+		// codeHash must be present and have correct length
+		if (codeHash == null || codeHash.length != 32)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+		// Impose a limit on 'limit'
+		if (limit != null && limit > 100)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			return repository.getATRepository().getATsByFunctionality(codeHash, isExecutable, limit, offset, reverse);
+		} catch (ApiException e) {
+			throw e;
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@GET
+	@Path("/{ataddress}")
+	@Operation(
+		summary = "Fetch info associated with AT address",
+		responses = {
+			@ApiResponse(
+				description = "automated transaction",
+				content = @Content(
+					schema = @Schema(implementation = ATData.class)
+				)
+			)
+		}
+	)
+	@ApiErrors({
+		ApiError.REPOSITORY_ISSUE
+	})
+	public ATData getByAddress(@PathParam("ataddress") String atAddress) {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			return repository.getATRepository().fromATAddress(atAddress);
+		} catch (ApiException e) {
+			throw e;
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@GET
+	@Path("/{ataddress}/data")
+	@Operation(
+		summary = "Fetch data segment associated with AT address",
+		responses = {
+			@ApiResponse(
+				description = "automated transaction",
+				content = @Content(
+					schema = @Schema(implementation = byte[].class)
+				)
+			)
+		}
+	)
+	@ApiErrors({
+		ApiError.REPOSITORY_ISSUE
+	})
+	public byte[] getDataByAddress(@PathParam("ataddress") String atAddress) {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			ATStateData atStateData = repository.getATRepository().getLatestATState(atAddress);
+			byte[] stateData = atStateData.getStateData();
+
+			QortalAtLoggerFactory loggerFactory = QortalAtLoggerFactory.getInstance();
+			byte[] dataBytes = MachineState.extractDataBytes(loggerFactory, stateData);
+
+			return dataBytes;
+		} catch (ApiException e) {
+			throw e;
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@POST
+	@Operation(
+		summary = "Build raw, unsigned, DEPLOY_AT transaction",
+		requestBody = @RequestBody(
+			required = true,
+			content = @Content(
+				mediaType = MediaType.APPLICATION_JSON,
+				schema = @Schema(
+					implementation = DeployAtTransactionData.class
+				)
+			)
+		),
+		responses = {
+			@ApiResponse(
+				description = "raw, unsigned, DEPLOY_AT transaction encoded in Base58",
+				content = @Content(
+					mediaType = MediaType.TEXT_PLAIN,
+					schema = @Schema(
+						type = "string"
+					)
+				)
+			)
+		}
+	)
+	@ApiErrors({ApiError.NON_PRODUCTION, ApiError.TRANSACTION_INVALID, ApiError.TRANSFORMATION_ERROR, ApiError.REPOSITORY_ISSUE})
+	public String createDeployAt(DeployAtTransactionData transactionData) {
+		if (Settings.getInstance().isApiRestricted())
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.NON_PRODUCTION);
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			Transaction transaction = Transaction.fromData(repository, transactionData);
+
+			ValidationResult result = transaction.isValidUnconfirmed();
+			if (result != ValidationResult.OK)
+				throw TransactionsResource.createTransactionInvalidException(request, result);
+
+			byte[] bytes = DeployAtTransactionTransformer.toBytes(transactionData);
+			return Base58.encode(bytes);
+		} catch (TransformationException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.TRANSFORMATION_ERROR, e);
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+}

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

@@ -22,9 +22,9 @@ import javax.ws.rs.core.MediaType;
 
 import org.qortal.api.ApiError;
 import org.qortal.api.ApiErrors;
-import org.qortal.api.ApiException;
 import org.qortal.api.ApiExceptionFactory;
-import org.qortal.api.model.BlockMinterSummary;
+import org.qortal.api.model.BlockInfo;
+import org.qortal.api.model.BlockSignerSummary;
 import org.qortal.crypto.Crypto;
 import org.qortal.data.account.AccountData;
 import org.qortal.data.block.BlockData;
@@ -71,9 +71,11 @@ public class BlocksResource {
 		}
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			return repository.getBlockRepository().fromSignature(signature);
-		} catch (ApiException e) {
-			throw e;
+			BlockData blockData = repository.getBlockRepository().fromSignature(signature);
+			if (blockData == null)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
+
+			return blockData;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -120,8 +122,6 @@ public class BlocksResource {
 				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
 
 			return repository.getBlockRepository().getTransactionsFromSignature(signature, limit, offset, reverse);
-		} catch (ApiException e) {
-			throw e;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -223,8 +223,6 @@ public class BlocksResource {
 				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
 
 			return childBlockData;
-		} catch (ApiException e) {
-			throw e;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -253,8 +251,6 @@ public class BlocksResource {
 	public int getHeight() {
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			return repository.getBlockRepository().getBlockchainHeight();
-		} catch (ApiException e) {
-			throw e;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -297,8 +293,6 @@ public class BlocksResource {
 				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
 
 			return blockData.getHeight();
-		} catch (ApiException e) {
-			throw e;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -330,8 +324,6 @@ public class BlocksResource {
 				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
 
 			return blockData;
-		} catch (ApiException e) {
-			throw e;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -366,8 +358,6 @@ public class BlocksResource {
 				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BLOCK_UNKNOWN);
 
 			return blockData;
-		} catch (ApiException e) {
-			throw e;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
@@ -416,9 +406,9 @@ public class BlocksResource {
 	}
 
 	@GET
-	@Path("/minter/{address}")
+	@Path("/signer/{address}")
 	@Operation(
-		summary = "Fetch block summaries for blocks minted by address",
+		summary = "Fetch block summaries for blocks signed by address",
 		responses = {
 			@ApiResponse(
 				description = "block summaries",
@@ -433,7 +423,7 @@ public class BlocksResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_ADDRESS, ApiError.PUBLIC_KEY_NOT_FOUND, ApiError.REPOSITORY_ISSUE})
-	public List<BlockSummaryData> getBlockSummariesByMinter(@PathParam("address") String address, @Parameter(
+	public List<BlockSummaryData> getBlockSummariesBySigner(@PathParam("address") String address, @Parameter(
 			ref = "limit"
 			) @QueryParam("limit") Integer limit, @Parameter(
 				ref = "offset"
@@ -449,32 +439,30 @@ public class BlocksResource {
 			if (accountData == null || accountData.getPublicKey() == null)
 				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.PUBLIC_KEY_NOT_FOUND);
 
-			return repository.getBlockRepository().getBlockSummariesByMinter(accountData.getPublicKey(), limit, offset, reverse);
-		} catch (ApiException e) {
-			throw e;
+			return repository.getBlockRepository().getBlockSummariesBySigner(accountData.getPublicKey(), limit, offset, reverse);
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}
 	}
 
 	@GET
-	@Path("/minters")
+	@Path("/signers")
 	@Operation(
-		summary = "Show summary of block minters",
-		description = "Returns count of blocks minted, optionally limited to minters/recipients in passed address(es).",
+		summary = "Show summary of block signers",
+		description = "Returns count of blocks signed, optionally limited to minters/recipients in passed address(es).",
 		responses = {
 			@ApiResponse(
 				content = @Content(
 					array = @ArraySchema(
 						schema = @Schema(
-							implementation = BlockMinterSummary.class
+							implementation = BlockSignerSummary.class
 						)
 					)
 				)
 			)
 		}
 	)
-	public List<BlockMinterSummary> getBlockMinters(@QueryParam("address") List<String> addresses,
+	public List<BlockSignerSummary> getBlockSigners(@QueryParam("address") List<String> addresses,
 			@Parameter(
 				ref = "limit"
 			) @QueryParam("limit") Integer limit, @Parameter(
@@ -487,7 +475,47 @@ public class BlocksResource {
 				if (!Crypto.isValidAddress(address))
 					throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
 
-			return repository.getBlockRepository().getBlockMinters(addresses, limit, offset, reverse);
+			return repository.getBlockRepository().getBlockSigners(addresses, limit, offset, reverse);
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@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/resource/ChatResource.java

@@ -0,0 +1,247 @@
+package org.qortal.api.resource;
+
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.Parameter;
+import io.swagger.v3.oas.annotations.media.ArraySchema;
+import io.swagger.v3.oas.annotations.media.Content;
+import io.swagger.v3.oas.annotations.media.Schema;
+import io.swagger.v3.oas.annotations.parameters.RequestBody;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.tags.Tag;
+
+import java.util.List;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.ws.rs.GET;
+import javax.ws.rs.POST;
+import javax.ws.rs.Path;
+import javax.ws.rs.PathParam;
+import javax.ws.rs.QueryParam;
+import javax.ws.rs.core.Context;
+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.Security;
+import org.qortal.crypto.Crypto;
+import org.qortal.data.chat.ActiveChats;
+import org.qortal.data.chat.ChatMessage;
+import org.qortal.data.transaction.ChatTransactionData;
+import org.qortal.data.transaction.TransactionData;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+import org.qortal.transaction.ChatTransaction;
+import org.qortal.transaction.Transaction;
+import org.qortal.transaction.Transaction.TransactionType;
+import org.qortal.transaction.Transaction.ValidationResult;
+import org.qortal.transform.TransformationException;
+import org.qortal.transform.transaction.ChatTransactionTransformer;
+import org.qortal.transform.transaction.TransactionTransformer;
+import org.qortal.utils.Base58;
+
+import com.google.common.primitives.Bytes;
+
+@Path("/chat")
+@Tag(name = "Chat")
+public class ChatResource {
+
+	@Context
+	HttpServletRequest request;
+
+	@GET
+	@Path("/messages")
+	@Operation(
+		summary = "Find chat messages",
+		description = "Returns CHAT messages that match criteria. Must provide EITHER 'txGroupId' OR two 'involving' addresses.",
+		responses = {
+			@ApiResponse(
+				description = "CHAT messages",
+				content = @Content(
+					array = @ArraySchema(
+						schema = @Schema(
+							implementation = ChatMessage.class
+						)
+					)
+				)
+			)
+		}
+	)
+	@ApiErrors({ApiError.INVALID_CRITERIA, ApiError.INVALID_ADDRESS, ApiError.REPOSITORY_ISSUE})
+	public List<ChatMessage> searchChat(@QueryParam("before") Long before, @QueryParam("after") Long after,
+			@QueryParam("txGroupId") Integer txGroupId,
+			@QueryParam("involving") List<String> involvingAddresses,
+			@Parameter(ref = "limit") @QueryParam("limit") Integer limit,
+			@Parameter(ref = "offset") @QueryParam("offset") Integer offset,
+			@Parameter(ref = "reverse") @QueryParam("reverse") Boolean reverse) {
+		// Check args meet expectations
+		if ((txGroupId == null && involvingAddresses.size() != 2)
+				|| (txGroupId != null && !involvingAddresses.isEmpty()))
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+		// Check any provided addresses are valid
+		if (involvingAddresses.stream().anyMatch(address -> !Crypto.isValidAddress(address)))
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
+
+		if (before != null && before < 1500000000000L)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+		if (after != null && after < 1500000000000L)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			return repository.getChatRepository().getMessagesMatchingCriteria(
+					before,
+					after,
+					txGroupId,
+					involvingAddresses,
+					limit, offset, reverse);
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@GET
+	@Path("/active/{address}")
+	@Operation(
+		summary = "Find active chats (group/direct) involving address",
+		responses = {
+			@ApiResponse(
+				content = @Content(
+					array = @ArraySchema(
+						schema = @Schema(
+							implementation = ActiveChats.class
+						)
+					)
+				)
+			)
+		}
+	)
+	@ApiErrors({ApiError.INVALID_CRITERIA, ApiError.INVALID_ADDRESS, ApiError.REPOSITORY_ISSUE})
+	public ActiveChats getActiveChats(@PathParam("address") String address) {
+		if (address == null || !Crypto.isValidAddress(address))
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			return repository.getChatRepository().getActiveChats(address);
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@POST
+	@Operation(
+		summary = "Build raw, unsigned, CHAT transaction",
+		description = "Builds a raw, unsigned CHAT transaction but does NOT compute proof-of-work nonce. See POST /chat/compute.",
+		requestBody = @RequestBody(
+			required = true,
+			content = @Content(
+				mediaType = MediaType.APPLICATION_JSON,
+				schema = @Schema(
+					implementation = ChatTransactionData.class
+				)
+			)
+		),
+		responses = {
+			@ApiResponse(
+				description = "raw, unsigned, CHAT transaction encoded in Base58",
+				content = @Content(
+					mediaType = MediaType.TEXT_PLAIN,
+					schema = @Schema(
+						type = "string"
+					)
+				)
+			)
+		}
+	)
+	@ApiErrors({ApiError.TRANSACTION_INVALID, ApiError.TRANSFORMATION_ERROR, ApiError.REPOSITORY_ISSUE})
+	public String buildChat(ChatTransactionData transactionData) {
+		Security.checkApiCallAllowed(request);
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			ChatTransaction chatTransaction = (ChatTransaction) Transaction.fromData(repository, transactionData);
+
+			ValidationResult result = chatTransaction.isValidUnconfirmed();
+			if (result != ValidationResult.OK)
+				throw TransactionsResource.createTransactionInvalidException(request, result);
+
+			byte[] bytes = ChatTransactionTransformer.toBytes(transactionData);
+			return Base58.encode(bytes);
+		} catch (TransformationException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.TRANSFORMATION_ERROR, e);
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@POST
+	@Path("/compute")
+	@Operation(
+		summary = "Compute nonce for raw, unsigned CHAT transaction",
+		requestBody = @RequestBody(
+			required = true,
+			content = @Content(
+				mediaType = MediaType.TEXT_PLAIN,
+				schema = @Schema(
+					type = "string",
+					description = "raw, unsigned CHAT transaction in base58 encoding",
+					example = "raw transaction base58"
+				)
+			)
+		),
+		responses = {
+			@ApiResponse(
+				description = "raw, unsigned, CHAT transaction encoded in Base58",
+				content = @Content(
+					mediaType = MediaType.TEXT_PLAIN,
+					schema = @Schema(
+						type = "string"
+					)
+				)
+			)
+		}
+	)
+	@ApiErrors({ApiError.TRANSACTION_INVALID, ApiError.INVALID_DATA, ApiError.TRANSFORMATION_ERROR, ApiError.REPOSITORY_ISSUE})
+	public String buildChat(String rawBytes58) {
+		Security.checkApiCallAllowed(request);
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			byte[] rawBytes = Base58.decode(rawBytes58);
+			// We're expecting unsigned transaction, so append empty signature prior to decoding
+			rawBytes = Bytes.concat(rawBytes, new byte[TransactionTransformer.SIGNATURE_LENGTH]);
+
+			TransactionData transactionData = TransactionTransformer.fromBytes(rawBytes);
+			if (transactionData == null)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_DATA);
+
+			if (transactionData.getType() != TransactionType.CHAT)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_DATA);
+
+			ChatTransaction chatTransaction = (ChatTransaction) Transaction.fromData(repository, transactionData);
+
+			// Quicker validity check first before we compute nonce
+			ValidationResult result = chatTransaction.isValid();
+			if (result != ValidationResult.OK)
+				throw TransactionsResource.createTransactionInvalidException(request, result);
+
+			chatTransaction.computeNonce();
+
+			// Re-check, but ignores signature
+			result = chatTransaction.isValidUnconfirmed();
+			if (result != ValidationResult.OK)
+				throw TransactionsResource.createTransactionInvalidException(request, result);
+
+			// Strip zeroed signature
+			transactionData.setSignature(null);
+
+			byte[] bytes = ChatTransactionTransformer.toBytes(transactionData);
+			return Base58.encode(bytes);
+		} catch (TransformationException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.TRANSFORMATION_ERROR, e);
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+}

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

@@ -0,0 +1,774 @@
+package org.qortal.api.resource;
+
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.Parameter;
+import io.swagger.v3.oas.annotations.media.ArraySchema;
+import io.swagger.v3.oas.annotations.media.Content;
+import io.swagger.v3.oas.annotations.media.Schema;
+import io.swagger.v3.oas.annotations.parameters.RequestBody;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.tags.Tag;
+
+import java.math.BigDecimal;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.ws.rs.DELETE;
+import javax.ws.rs.GET;
+import javax.ws.rs.POST;
+import javax.ws.rs.Path;
+import javax.ws.rs.QueryParam;
+import javax.ws.rs.core.Context;
+import javax.ws.rs.core.MediaType;
+
+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.TransactionOutput;
+import org.qortal.account.PublicKeyAccount;
+import org.qortal.api.ApiError;
+import org.qortal.api.ApiErrors;
+import org.qortal.api.ApiException;
+import org.qortal.api.ApiExceptionFactory;
+import org.qortal.api.model.CrossChainCancelRequest;
+import org.qortal.api.model.CrossChainSecretRequest;
+import org.qortal.api.model.CrossChainTradeRequest;
+import org.qortal.api.model.CrossChainBitcoinP2SHStatus;
+import org.qortal.api.model.CrossChainBitcoinRedeemRequest;
+import org.qortal.api.model.CrossChainBitcoinRefundRequest;
+import org.qortal.api.model.CrossChainBitcoinTemplateRequest;
+import org.qortal.api.model.CrossChainBuildRequest;
+import org.qortal.asset.Asset;
+import org.qortal.crosschain.BTC;
+import org.qortal.crosschain.BTCACCT;
+import org.qortal.crypto.Crypto;
+import org.qortal.data.at.ATData;
+import org.qortal.data.crosschain.CrossChainTradeData;
+import org.qortal.data.crosschain.CrossChainTradeData.Mode;
+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.transaction.DeployAtTransaction;
+import org.qortal.transaction.MessageTransaction;
+import org.qortal.transaction.Transaction;
+import org.qortal.transaction.Transaction.ValidationResult;
+import org.qortal.transform.TransformationException;
+import org.qortal.transform.Transformer;
+import org.qortal.transform.transaction.DeployAtTransactionTransformer;
+import org.qortal.transform.transaction.MessageTransactionTransformer;
+import org.qortal.utils.Base58;
+import org.qortal.utils.NTP;
+
+import com.google.common.primitives.Bytes;
+
+@Path("/crosschain")
+@Tag(name = "Cross-Chain")
+public class CrossChainResource {
+
+	@Context
+	HttpServletRequest request;
+
+	@GET
+	@Path("/tradeoffers")
+	@Operation(
+		summary = "Find cross-chain trade offers",
+		responses = {
+			@ApiResponse(
+				description = "automated transactions",
+				content = @Content(
+					array = @ArraySchema(
+						schema = @Schema(
+							implementation = CrossChainTradeData.class
+						)
+					)
+				)
+			)
+		}
+	)
+	@ApiErrors({ApiError.INVALID_CRITERIA, ApiError.REPOSITORY_ISSUE})
+	public List<CrossChainTradeData> getTradeOffers(
+			@Parameter( ref = "limit") @QueryParam("limit") Integer limit,
+			@Parameter( ref = "offset" ) @QueryParam("offset") Integer offset,
+			@Parameter( ref = "reverse" ) @QueryParam("reverse") Boolean reverse) {
+		// Impose a limit on 'limit'
+		if (limit != null && limit > 100)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+		byte[] codeHash = BTCACCT.CODE_BYTES_HASH;
+		boolean isExecutable = true;
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			List<ATData> atsData = repository.getATRepository().getATsByFunctionality(codeHash, isExecutable, limit, offset, reverse);
+
+			List<CrossChainTradeData> crossChainTradesData = new ArrayList<>();
+			for (ATData atData : atsData) {
+				CrossChainTradeData crossChainTradeData = BTCACCT.populateTradeData(repository, atData);
+				crossChainTradesData.add(crossChainTradeData);
+			}
+
+			return crossChainTradesData;
+		} catch (ApiException e) {
+			throw e;
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@POST
+	@Path("/build")
+	@Operation(
+		summary = "Build cross-chain trading AT",
+		description = "Returns raw, unsigned DEPLOY_AT transaction",
+		requestBody = @RequestBody(
+			required = true,
+			content = @Content(
+				mediaType = MediaType.APPLICATION_JSON,
+				schema = @Schema(
+					implementation = CrossChainBuildRequest.class
+				)
+			)
+		),
+		responses = {
+			@ApiResponse(
+				content = @Content(mediaType = MediaType.TEXT_PLAIN, schema = @Schema(type = "string"))
+			)
+		}
+	)
+	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_DATA, ApiError.INVALID_REFERENCE, ApiError.TRANSFORMATION_ERROR, ApiError.REPOSITORY_ISSUE})
+	public String buildTrade(CrossChainBuildRequest tradeRequest) {
+		byte[] creatorPublicKey = tradeRequest.creatorPublicKey;
+
+		if (creatorPublicKey == null || creatorPublicKey.length != Transformer.PUBLIC_KEY_LENGTH)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PUBLIC_KEY);
+
+		if (tradeRequest.secretHash == null || tradeRequest.secretHash.length != BTC.HASH160_LENGTH)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_DATA);
+
+		if (tradeRequest.tradeTimeout == null)
+			tradeRequest.tradeTimeout = 7 * 24 * 60; // 7 days
+		else
+			if (tradeRequest.tradeTimeout < 10 || tradeRequest.tradeTimeout > 50000)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_DATA);
+
+		if (tradeRequest.initialQortAmount < 0)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_DATA);
+
+		if (tradeRequest.finalQortAmount <= 0)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_DATA);
+
+		if (tradeRequest.fundingQortAmount <= 0)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_DATA);
+
+		// funding amount must exceed initial + final
+		if (tradeRequest.fundingQortAmount <= tradeRequest.initialQortAmount + tradeRequest.finalQortAmount)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_DATA);
+
+		if (tradeRequest.bitcoinAmount <= 0)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_DATA);
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			PublicKeyAccount creatorAccount = new PublicKeyAccount(repository, creatorPublicKey);
+
+			byte[] creationBytes = BTCACCT.buildQortalAT(creatorAccount.getAddress(), tradeRequest.secretHash, tradeRequest.tradeTimeout, tradeRequest.initialQortAmount, tradeRequest.finalQortAmount, tradeRequest.bitcoinAmount);
+
+			long txTimestamp = NTP.getTime();
+			byte[] lastReference = creatorAccount.getLastReference();
+			if (lastReference == null)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_REFERENCE);
+
+			long fee = 0;
+			String name = "QORT-BTC cross-chain trade";
+			String description = "Qortal-Bitcoin cross-chain trade";
+			String atType = "ACCT";
+			String tags = "QORT-BTC ACCT";
+
+			BaseTransactionData baseTransactionData = new BaseTransactionData(txTimestamp, Group.NO_GROUP, lastReference, creatorAccount.getPublicKey(), fee, null);
+			TransactionData deployAtTransactionData = new DeployAtTransactionData(baseTransactionData, name, description, atType, tags, creationBytes, tradeRequest.fundingQortAmount, Asset.QORT);
+
+			Transaction deployAtTransaction = new DeployAtTransaction(repository, deployAtTransactionData);
+
+			fee = deployAtTransaction.calcRecommendedFee();
+			deployAtTransactionData.setFee(fee);
+
+			ValidationResult result = deployAtTransaction.isValidUnconfirmed();
+			if (result != ValidationResult.OK)
+				throw TransactionsResource.createTransactionInvalidException(request, result);
+
+			byte[] bytes = DeployAtTransactionTransformer.toBytes(deployAtTransactionData);
+			return Base58.encode(bytes);
+		} catch (TransformationException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.TRANSFORMATION_ERROR, e);
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@POST
+	@Path("/tradeoffer/recipient")
+	@Operation(
+		summary = "Builds raw, unsigned MESSAGE transaction that sends cross-chain trade recipient address, triggering 'trade' mode",
+		description = "Specify address of cross-chain AT that needs to be messaged, and address of Qortal recipient.<br>"
+			+ "AT needs to be in 'offer' mode. Messages sent to an AT in 'trade' mode will be ignored, but still cost fees to send!<br>"
+			+ "You need to sign output with same account as the AT creator otherwise the MESSAGE transaction will be invalid.",
+		requestBody = @RequestBody(
+			required = true,
+			content = @Content(
+				mediaType = MediaType.APPLICATION_JSON,
+				schema = @Schema(
+					implementation = CrossChainTradeRequest.class
+				)
+			)
+		),
+		responses = {
+			@ApiResponse(
+				content = @Content(
+					schema = @Schema(
+						type = "string"
+					)
+				)
+			)
+		}
+	)
+	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.INVALID_CRITERIA, ApiError.REPOSITORY_ISSUE})
+	public String sendTradeRecipient(CrossChainTradeRequest tradeRequest) {
+		byte[] creatorPublicKey = tradeRequest.creatorPublicKey;
+
+		if (creatorPublicKey == null || creatorPublicKey.length != Transformer.PUBLIC_KEY_LENGTH)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PUBLIC_KEY);
+
+		if (tradeRequest.atAddress == null || !Crypto.isValidAtAddress(tradeRequest.atAddress))
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
+
+		if (tradeRequest.recipient == null || !Crypto.isValidAddress(tradeRequest.recipient))
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			ATData atData = fetchAtDataWithChecking(repository, creatorPublicKey, tradeRequest.atAddress);
+			CrossChainTradeData crossChainTradeData = BTCACCT.populateTradeData(repository, atData);
+
+			if (crossChainTradeData.mode == CrossChainTradeData.Mode.TRADE)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+			// Good to make MESSAGE
+
+			byte[] recipientAddressBytes = Bytes.ensureCapacity(Base58.decode(tradeRequest.recipient), 32, 0);
+			byte[] messageTransactionBytes = buildAtMessage(repository, creatorPublicKey, tradeRequest.atAddress, recipientAddressBytes);
+
+			return Base58.encode(messageTransactionBytes);
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@POST
+	@Path("/tradeoffer/secret")
+	@Operation(
+		summary = "Builds raw, unsigned MESSAGE transaction that sends secret to AT, releasing funds to recipient",
+		description = "Specify address of cross-chain AT that needs to be messaged, and 32-byte secret.<br>"
+			+ "AT needs to be in 'trade' mode. Messages sent to an AT in 'trade' mode will be ignored, but still cost fees to send!<br>"
+			+ "You need to sign output with account the AT considers the 'recipient' otherwise the MESSAGE transaction will be invalid.",
+		requestBody = @RequestBody(
+			required = true,
+			content = @Content(
+				mediaType = MediaType.APPLICATION_JSON,
+				schema = @Schema(
+					implementation = CrossChainSecretRequest.class
+				)
+			)
+		),
+		responses = {
+			@ApiResponse(
+				content = @Content(
+					schema = @Schema(
+						type = "string"
+					)
+				)
+			)
+		}
+	)
+	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.INVALID_DATA, ApiError.INVALID_CRITERIA, ApiError.REPOSITORY_ISSUE})
+	public String sendSecret(CrossChainSecretRequest secretRequest) {
+		byte[] recipientPublicKey = secretRequest.recipientPublicKey;
+
+		if (recipientPublicKey == null || recipientPublicKey.length != Transformer.PUBLIC_KEY_LENGTH)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PUBLIC_KEY);
+
+		if (secretRequest.atAddress == null || !Crypto.isValidAtAddress(secretRequest.atAddress))
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
+
+		if (secretRequest.secret == null || secretRequest.secret.length != BTCACCT.SECRET_LENGTH)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_DATA);
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			ATData atData = fetchAtDataWithChecking(repository, null, secretRequest.atAddress); // null to skip creator check
+			CrossChainTradeData crossChainTradeData = BTCACCT.populateTradeData(repository, atData);
+
+			if (crossChainTradeData.mode == CrossChainTradeData.Mode.OFFER)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+			PublicKeyAccount recipientAccount = new PublicKeyAccount(repository, recipientPublicKey);
+			String recipientAddress = recipientAccount.getAddress();
+
+			// MESSAGE must come from address that AT considers trade partner / 'recipient'
+			if (!crossChainTradeData.qortalRecipient.equals(recipientAddress))
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
+
+			// Good to make MESSAGE
+
+			byte[] messageTransactionBytes = buildAtMessage(repository, recipientPublicKey, secretRequest.atAddress, secretRequest.secret);
+
+			return Base58.encode(messageTransactionBytes);
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@DELETE
+	@Path("/tradeoffer")
+	@Operation(
+		summary = "Builds raw, unsigned MESSAGE transaction that cancels cross-chain trade offer",
+		description = "Specify address of cross-chain AT that needs to be cancelled.<br>"
+			+ "AT needs to be in 'offer' mode. Messages sent to an AT in 'trade' mode will be ignored, but still cost fees to send!<br>"
+			+ "You need to sign output with same account as the AT creator otherwise the MESSAGE transaction will be invalid.",
+		requestBody = @RequestBody(
+			required = true,
+			content = @Content(
+				mediaType = MediaType.APPLICATION_JSON,
+				schema = @Schema(
+					implementation = CrossChainCancelRequest.class
+				)
+			)
+		),
+		responses = {
+			@ApiResponse(
+				content = @Content(
+					schema = @Schema(
+						type = "string"
+					)
+				)
+			)
+		}
+	)
+	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.INVALID_CRITERIA, ApiError.REPOSITORY_ISSUE})
+	public String cancelTradeOffer(CrossChainCancelRequest cancelRequest) {
+		byte[] creatorPublicKey = cancelRequest.creatorPublicKey;
+
+		if (creatorPublicKey == null || creatorPublicKey.length != Transformer.PUBLIC_KEY_LENGTH)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PUBLIC_KEY);
+
+		if (cancelRequest.atAddress == null || !Crypto.isValidAtAddress(cancelRequest.atAddress))
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			ATData atData = fetchAtDataWithChecking(repository, creatorPublicKey, cancelRequest.atAddress);
+			CrossChainTradeData crossChainTradeData = BTCACCT.populateTradeData(repository, atData);
+
+			if (crossChainTradeData.mode == CrossChainTradeData.Mode.TRADE)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+			// Good to make MESSAGE
+
+			PublicKeyAccount creatorAccount = new PublicKeyAccount(repository, creatorPublicKey);
+			String creatorAddress = creatorAccount.getAddress();
+			byte[] recipientAddressBytes = Bytes.ensureCapacity(Base58.decode(creatorAddress), 32, 0);
+
+			byte[] messageTransactionBytes = buildAtMessage(repository, creatorPublicKey, cancelRequest.atAddress, recipientAddressBytes);
+
+			return Base58.encode(messageTransactionBytes);
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@POST
+	@Path("/p2sh")
+	@Operation(
+		summary = "Returns Bitcoin P2SH address based on trade info",
+		requestBody = @RequestBody(
+			required = true,
+			content = @Content(
+				mediaType = MediaType.APPLICATION_JSON,
+				schema = @Schema(
+					implementation = CrossChainBitcoinTemplateRequest.class
+				)
+			)
+		),
+		responses = {
+			@ApiResponse(
+				content = @Content(mediaType = MediaType.TEXT_PLAIN, schema = @Schema(type = "string"))
+			)
+		}
+	)
+	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.REPOSITORY_ISSUE})
+	public String deriveP2sh(CrossChainBitcoinTemplateRequest templateRequest) {
+		BTC btc = BTC.getInstance();
+		NetworkParameters params = btc.getNetworkParameters();
+
+		if (templateRequest.refundPublicKeyHash == null || templateRequest.refundPublicKeyHash.length != 20)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PUBLIC_KEY);
+
+		if (templateRequest.redeemPublicKeyHash == null || templateRequest.redeemPublicKeyHash.length != 20)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PUBLIC_KEY);
+
+		if (templateRequest.atAddress == null || !Crypto.isValidAtAddress(templateRequest.atAddress))
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
+
+		// Extract data from cross-chain trading AT
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			ATData atData = fetchAtDataWithChecking(repository, null, templateRequest.atAddress); // null to skip creator check
+			CrossChainTradeData crossChainTradeData = BTCACCT.populateTradeData(repository, atData);
+
+			if (crossChainTradeData.mode == Mode.OFFER)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+			byte[] redeemScriptBytes = BTCACCT.buildScript(templateRequest.refundPublicKeyHash, crossChainTradeData.lockTime, templateRequest.redeemPublicKeyHash, crossChainTradeData.secretHash);
+			byte[] redeemScriptHash = Crypto.hash160(redeemScriptBytes);
+
+			Address p2shAddress = LegacyAddress.fromScriptHash(params, redeemScriptHash);
+			return p2shAddress.toString();
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@POST
+	@Path("/p2sh/check")
+	@Operation(
+		summary = "Checks Bitcoin P2SH address based on trade info",
+		requestBody = @RequestBody(
+			required = true,
+			content = @Content(
+				mediaType = MediaType.APPLICATION_JSON,
+				schema = @Schema(
+					implementation = CrossChainBitcoinTemplateRequest.class
+				)
+			)
+		),
+		responses = {
+			@ApiResponse(
+				content = @Content(mediaType = MediaType.APPLICATION_JSON, schema = @Schema(implementation = CrossChainBitcoinP2SHStatus.class))
+			)
+		}
+	)
+	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN, ApiError.REPOSITORY_ISSUE})
+	public CrossChainBitcoinP2SHStatus checkP2sh(CrossChainBitcoinTemplateRequest templateRequest) {
+		BTC btc = BTC.getInstance();
+		NetworkParameters params = btc.getNetworkParameters();
+
+		if (templateRequest.refundPublicKeyHash == null || templateRequest.refundPublicKeyHash.length != 20)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PUBLIC_KEY);
+
+		if (templateRequest.redeemPublicKeyHash == null || templateRequest.redeemPublicKeyHash.length != 20)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PUBLIC_KEY);
+
+		if (templateRequest.atAddress == null || !Crypto.isValidAtAddress(templateRequest.atAddress))
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
+
+		// Extract data from cross-chain trading AT
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			ATData atData = fetchAtDataWithChecking(repository, null, templateRequest.atAddress); // null to skip creator check
+			CrossChainTradeData crossChainTradeData = BTCACCT.populateTradeData(repository, atData);
+
+			if (crossChainTradeData.mode == Mode.OFFER)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+			byte[] redeemScriptBytes = BTCACCT.buildScript(templateRequest.refundPublicKeyHash, crossChainTradeData.lockTime, templateRequest.redeemPublicKeyHash, crossChainTradeData.secretHash);
+			byte[] redeemScriptHash = Crypto.hash160(redeemScriptBytes);
+
+			Address p2shAddress = LegacyAddress.fromScriptHash(params, redeemScriptHash);
+
+			Integer medianBlockTime = BTC.getInstance().getMedianBlockTime();
+			if (medianBlockTime == null)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BTC_NETWORK_ISSUE);
+
+			long now = NTP.getTime();
+
+			// Check P2SH is funded
+
+			Coin p2shBalance = BTC.getInstance().getBalance(p2shAddress.toString());
+			if (p2shBalance == null)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.ADDRESS_UNKNOWN);
+
+			CrossChainBitcoinP2SHStatus p2shStatus = new CrossChainBitcoinP2SHStatus();
+			p2shStatus.bitcoinP2shAddress = p2shAddress.toString();
+			p2shStatus.bitcoinP2shBalance = BigDecimal.valueOf(p2shBalance.value, 8);
+
+			List<TransactionOutput> fundingOutputs = BTC.getInstance().getUnspentOutputs(p2shAddress.toString());
+
+			if (p2shBalance.value >= crossChainTradeData.expectedBitcoin && !fundingOutputs.isEmpty()) {
+				p2shStatus.canRedeem = now >= medianBlockTime * 1000L;
+				p2shStatus.canRefund = now >= crossChainTradeData.lockTime * 1000L;
+			}
+
+			if (now >= medianBlockTime * 1000L) {
+				// See if we can extract secret
+				List<byte[]> rawTransactions = BTC.getInstance().getAddressTransactions(p2shStatus.bitcoinP2shAddress);
+				p2shStatus.secret = BTCACCT.findP2shSecret(p2shStatus.bitcoinP2shAddress, rawTransactions);
+			}
+
+			return p2shStatus;
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@POST
+	@Path("/p2sh/refund")
+	@Operation(
+		summary = "Returns serialized Bitcoin transaction attempting refund from P2SH address",
+		requestBody = @RequestBody(
+			required = true,
+			content = @Content(
+				mediaType = MediaType.APPLICATION_JSON,
+				schema = @Schema(
+					implementation = CrossChainBitcoinRefundRequest.class
+				)
+			)
+		),
+		responses = {
+			@ApiResponse(
+				content = @Content(mediaType = MediaType.TEXT_PLAIN, schema = @Schema(type = "string"))
+			)
+		}
+	)
+	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN,
+		ApiError.BTC_TOO_SOON, ApiError.BTC_BALANCE_ISSUE, ApiError.BTC_NETWORK_ISSUE, ApiError.REPOSITORY_ISSUE})
+	public String refundP2sh(CrossChainBitcoinRefundRequest refundRequest) {
+		BTC btc = BTC.getInstance();
+		NetworkParameters params = btc.getNetworkParameters();
+
+		byte[] refundPrivateKey = refundRequest.refundPrivateKey;
+		if (refundPrivateKey == null)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PRIVATE_KEY);
+
+		ECKey refundKey = null;
+
+		try {
+			// Auto-trim
+			if (refundPrivateKey.length >= 37 && refundPrivateKey.length <= 38)
+				refundPrivateKey = Arrays.copyOfRange(refundPrivateKey, 1, 33);
+			if (refundPrivateKey.length != 32)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PRIVATE_KEY);
+
+			refundKey = ECKey.fromPrivate(refundPrivateKey);
+		} catch (IllegalArgumentException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PRIVATE_KEY);
+		}
+
+		if (refundRequest.redeemPublicKeyHash == null || refundRequest.redeemPublicKeyHash.length != 20)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PUBLIC_KEY);
+
+		if (refundRequest.atAddress == null || !Crypto.isValidAtAddress(refundRequest.atAddress))
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
+
+		// Extract data from cross-chain trading AT
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			ATData atData = fetchAtDataWithChecking(repository, null, refundRequest.atAddress); // null to skip creator check
+			CrossChainTradeData crossChainTradeData = BTCACCT.populateTradeData(repository, atData);
+
+			if (crossChainTradeData.mode == Mode.OFFER)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+			byte[] redeemScriptBytes = BTCACCT.buildScript(refundKey.getPubKeyHash(), crossChainTradeData.lockTime, refundRequest.redeemPublicKeyHash, crossChainTradeData.secretHash);
+			byte[] redeemScriptHash = Crypto.hash160(redeemScriptBytes);
+
+			Address p2shAddress = LegacyAddress.fromScriptHash(params, redeemScriptHash);
+
+			long now = NTP.getTime();
+
+			// Check P2SH is funded
+
+			Coin p2shBalance = BTC.getInstance().getBalance(p2shAddress.toString());
+			if (p2shBalance == null)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.ADDRESS_UNKNOWN);
+
+			List<TransactionOutput> fundingOutputs = BTC.getInstance().getUnspentOutputs(p2shAddress.toString());
+			if (fundingOutputs.isEmpty())
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
+
+			boolean canRefund = now >= crossChainTradeData.lockTime * 1000L;
+			if (!canRefund)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BTC_TOO_SOON);
+
+			if (p2shBalance.value < crossChainTradeData.expectedBitcoin)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BTC_BALANCE_ISSUE);
+
+			Coin refundAmount = p2shBalance.subtract(Coin.valueOf(refundRequest.bitcoinMinerFee.unscaledValue().longValue()));
+
+			org.bitcoinj.core.Transaction refundTransaction = BTCACCT.buildRefundTransaction(refundAmount, refundKey, fundingOutputs, redeemScriptBytes, crossChainTradeData.lockTime);
+			boolean wasBroadcast = BTC.getInstance().broadcastTransaction(refundTransaction);
+
+			if (!wasBroadcast)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BTC_NETWORK_ISSUE);
+
+			return refundTransaction.getTxId().toString();
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	@POST
+	@Path("/p2sh/redeem")
+	@Operation(
+		summary = "Returns serialized Bitcoin transaction attempting redeem from P2SH address",
+		requestBody = @RequestBody(
+			required = true,
+			content = @Content(
+				mediaType = MediaType.APPLICATION_JSON,
+				schema = @Schema(
+					implementation = CrossChainBitcoinRedeemRequest.class
+				)
+			)
+		),
+		responses = {
+			@ApiResponse(
+				content = @Content(mediaType = MediaType.TEXT_PLAIN, schema = @Schema(type = "string"))
+			)
+		}
+	)
+	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN,
+		ApiError.BTC_TOO_SOON, ApiError.BTC_BALANCE_ISSUE, ApiError.BTC_NETWORK_ISSUE, ApiError.REPOSITORY_ISSUE})
+	public String redeemP2sh(CrossChainBitcoinRedeemRequest redeemRequest) {
+		BTC btc = BTC.getInstance();
+		NetworkParameters params = btc.getNetworkParameters();
+
+		byte[] redeemPrivateKey = redeemRequest.redeemPrivateKey;
+		if (redeemPrivateKey == null)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PRIVATE_KEY);
+
+		ECKey redeemKey = null;
+
+		try {
+			// Auto-trim
+			if (redeemPrivateKey.length >= 37 && redeemPrivateKey.length <= 38)
+				redeemPrivateKey = Arrays.copyOfRange(redeemPrivateKey, 1, 33);
+			if (redeemPrivateKey.length != 32)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PRIVATE_KEY);
+
+			redeemKey = ECKey.fromPrivate(redeemPrivateKey);
+		} catch (IllegalArgumentException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PRIVATE_KEY);
+		}
+
+		if (redeemRequest.refundPublicKeyHash == null || redeemRequest.refundPublicKeyHash.length != 20)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PUBLIC_KEY);
+
+		if (redeemRequest.atAddress == null || !Crypto.isValidAtAddress(redeemRequest.atAddress))
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
+
+		if (redeemRequest.secret == null || redeemRequest.secret.length != BTCACCT.SECRET_LENGTH)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_DATA);
+
+		// Extract data from cross-chain trading AT
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			ATData atData = fetchAtDataWithChecking(repository, null, redeemRequest.atAddress); // null to skip creator check
+			CrossChainTradeData crossChainTradeData = BTCACCT.populateTradeData(repository, atData);
+
+			if (crossChainTradeData.mode == Mode.OFFER)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+			byte[] redeemScriptBytes = BTCACCT.buildScript(redeemRequest.refundPublicKeyHash, crossChainTradeData.lockTime, redeemKey.getPubKeyHash(), crossChainTradeData.secretHash);
+			byte[] redeemScriptHash = Crypto.hash160(redeemScriptBytes);
+
+			Address p2shAddress = LegacyAddress.fromScriptHash(params, redeemScriptHash);
+
+			Integer medianBlockTime = BTC.getInstance().getMedianBlockTime();
+			if (medianBlockTime == null)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BTC_NETWORK_ISSUE);
+
+			long now = NTP.getTime();
+
+			// Check P2SH is funded
+			Coin p2shBalance = BTC.getInstance().getBalance(p2shAddress.toString());
+			if (p2shBalance == null)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.ADDRESS_UNKNOWN);
+
+			if (p2shBalance.value < crossChainTradeData.expectedBitcoin)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BTC_BALANCE_ISSUE);
+
+			List<TransactionOutput> fundingOutputs = BTC.getInstance().getUnspentOutputs(p2shAddress.toString());
+			if (fundingOutputs.isEmpty())
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
+
+			boolean canRedeem = now >= medianBlockTime * 1000L;
+			if (!canRedeem)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BTC_TOO_SOON);
+
+			Coin redeemAmount = p2shBalance.subtract(Coin.valueOf(redeemRequest.bitcoinMinerFee.unscaledValue().longValue()));
+
+			org.bitcoinj.core.Transaction redeemTransaction = BTCACCT.buildRedeemTransaction(redeemAmount, redeemKey, fundingOutputs, redeemScriptBytes, redeemRequest.secret);
+			boolean wasBroadcast = BTC.getInstance().broadcastTransaction(redeemTransaction);
+
+			if (!wasBroadcast)
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.BTC_NETWORK_ISSUE);
+
+			return redeemTransaction.getTxId().toString();
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
+	private ATData fetchAtDataWithChecking(Repository repository, byte[] creatorPublicKey, String atAddress) throws DataException {
+		ATData atData = repository.getATRepository().fromATAddress(atAddress);
+		if (atData == null)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.ADDRESS_UNKNOWN);
+
+		// Does supplied public key match that of AT?
+		if (creatorPublicKey != null && !Arrays.equals(creatorPublicKey, atData.getCreatorPublicKey()))
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PUBLIC_KEY);
+
+		// Must be correct AT - check functionality using code hash
+		if (!Arrays.equals(atData.getCodeHash(), BTCACCT.CODE_BYTES_HASH))
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+		// No point sending message to AT that's finished
+		if (atData.getIsFinished())
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_CRITERIA);
+
+		return atData;
+	}
+
+	private byte[] buildAtMessage(Repository repository, byte[] senderPublicKey, String atAddress, byte[] messageData) throws DataException {
+		PublicKeyAccount creatorAccount = new PublicKeyAccount(repository, senderPublicKey);
+
+		long txTimestamp = NTP.getTime();
+		byte[] lastReference = creatorAccount.getLastReference();
+
+		if (lastReference == null)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_REFERENCE);
+
+		int version = 4;
+		int nonce = 0;
+		long amount = 0L;
+		Long assetId = null; // no assetId as amount is zero
+		Long fee = null;
+
+		BaseTransactionData baseTransactionData = new BaseTransactionData(txTimestamp, Group.NO_GROUP, lastReference, senderPublicKey, fee, null);
+		TransactionData messageTransactionData = new MessageTransactionData(baseTransactionData, version, nonce, atAddress, amount, assetId, messageData, false, false);
+
+		MessageTransaction messageTransaction = new MessageTransaction(repository, messageTransactionData);
+
+		fee = messageTransaction.calcRecommendedFee();
+		messageTransactionData.setFee(fee);
+
+		ValidationResult result = messageTransaction.isValidUnconfirmed();
+		if (result != ValidationResult.OK)
+			throw TransactionsResource.createTransactionInvalidException(request, result);
+
+		try {
+			return MessageTransactionTransformer.toBytes(messageTransactionData);
+		} catch (TransformationException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.TRANSFORMATION_ERROR, e);
+		}
+	}
+
+}

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

@@ -8,6 +8,7 @@ import io.swagger.v3.oas.annotations.parameters.RequestBody;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import io.swagger.v3.oas.annotations.tags.Tag;
 
+import java.util.ArrayList;
 import java.util.List;
 import java.util.stream.Collectors;
 
@@ -29,9 +30,8 @@ import org.qortal.data.network.PeerData;
 import org.qortal.network.Network;
 import org.qortal.network.PeerAddress;
 import org.qortal.repository.DataException;
-import org.qortal.repository.Repository;
-import org.qortal.repository.RepositoryManager;
 import org.qortal.utils.ExecuteProduceConsume;
+import org.qortal.utils.NTP;
 
 @Path("/peers")
 @Tag(name = "Peers")
@@ -81,11 +81,7 @@ public class PeersResource {
 		ApiError.REPOSITORY_ISSUE
 	})
 	public List<PeerData> getKnownPeers() {
-		try (final Repository repository = RepositoryManager.getRepository()) {
-			return repository.getNetworkRepository().getAllPeers();
-		} catch (DataException e) {
-			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
-		}
+		return Network.getInstance().getAllKnownPeers();
 	}
 
 	@GET
@@ -166,18 +162,21 @@ public class PeersResource {
 	public String addPeer(String address) {
 		Security.checkApiCallAllowed(request);
 
-		try (final Repository repository = RepositoryManager.getRepository()) {
+		final Long addedWhen = NTP.getTime();
+		if (addedWhen == null)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.NO_TIME_SYNC);
+
+		try {
 			PeerAddress peerAddress = PeerAddress.fromString(address);
 
-			PeerData peerData = new PeerData(peerAddress, System.currentTimeMillis(), "API");
-			repository.getNetworkRepository().save(peerData);
-			repository.saveChanges();
+			List<PeerAddress> newPeerAddresses = new ArrayList<>(1);
+			newPeerAddresses.add(peerAddress);
 
-			return "true";
+			boolean addResult = Network.getInstance().mergePeers("API", addedWhen, newPeerAddresses);
+
+			return addResult ? "true" : "false";
 		} catch (IllegalArgumentException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_NETWORK_ADDRESS);
-		} catch (ApiException e) {
-			throw e;
 		} catch (DataException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
 		}

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

@@ -363,6 +363,60 @@ public class TransactionsResource {
 		}
 	}
 
+	@GET
+	@Path("/creator/{publickey}")
+	@Operation(
+		summary = "Find matching transactions created by account with given public key",
+		responses = {
+			@ApiResponse(
+				description = "transactions",
+				content = @Content(
+					array = @ArraySchema(
+						schema = @Schema(
+							implementation = TransactionData.class
+						)
+					)
+				)
+			)
+		}
+	)
+	@ApiErrors({
+		ApiError.INVALID_CRITERIA, ApiError.REPOSITORY_ISSUE
+	})
+	public List<TransactionData> findCreatorsTransactions(@PathParam("publickey") String publicKey58,
+			@Parameter(
+				description = "whether to include confirmed, unconfirmed or both",
+				required = true
+			) @QueryParam("confirmationStatus") ConfirmationStatus confirmationStatus, @Parameter(
+				ref = "limit"
+			) @QueryParam("limit") Integer limit, @Parameter(
+				ref = "offset"
+			) @QueryParam("offset") Integer offset, @Parameter(
+				ref = "reverse"
+			) @QueryParam("reverse") Boolean reverse) {
+		// Decode public key
+		byte[] publicKey;
+		try {
+			publicKey = Base58.decode(publicKey58);
+		} catch (NumberFormatException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_PUBLIC_KEY, e);
+		}
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			List<byte[]> signatures = repository.getTransactionRepository().getSignaturesMatchingCriteria(null,
+					publicKey, confirmationStatus, limit, offset, reverse);
+
+			// Expand signatures to transactions
+			List<TransactionData> transactions = new ArrayList<>(signatures.size());
+			for (byte[] signature : signatures)
+				transactions.add(repository.getTransactionRepository().fromSignature(signature));
+
+			return transactions;
+		} catch (DataException e) {
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		}
+	}
+
 	@POST
 	@Path("/sign")
 	@Operation(
@@ -477,14 +531,14 @@ public class TransactionsResource {
 				ValidationResult result = transaction.importAsUnconfirmed();
 				if (result != ValidationResult.OK)
 					throw createTransactionInvalidException(request, result);
-
-				// Notify controller of new transaction
-				Controller.getInstance().onNewTransaction(transactionData);
-
-				return "true";
 			} finally {
 				blockchainLock.unlock();
 			}
+
+			// Notify controller of new transaction
+			Controller.getInstance().onNewTransaction(transactionData, null);
+
+			return "true";
 		} catch (NumberFormatException e) {
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_DATA, e);
 		} catch (TransformationException e) {

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

@@ -0,0 +1,93 @@
+package org.qortal.api.websocket;
+
+import java.io.IOException;
+import java.io.StringWriter;
+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;
+import org.qortal.data.chat.ActiveChats;
+import org.qortal.data.transaction.ChatTransactionData;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+
+@WebSocket
+@SuppressWarnings("serial")
+public class ActiveChatsWebSocket extends WebSocketServlet implements ApiWebSocket {
+
+	@Override
+	public void configure(WebSocketServletFactory factory) {
+		factory.register(ActiveChatsWebSocket.class);
+	}
+
+	@OnWebSocketConnect
+	public void onWebSocketConnect(Session session) {
+		Map<String, String> pathParams = this.getPathParams(session, "/{address}");
+
+		String address = pathParams.get("address");
+		if (address == null || !Crypto.isValidAddress(address)) {
+			session.close(4001, "invalid address");
+			return;
+		}
+
+		AtomicReference<String> previousOutput = new AtomicReference<>(null);
+
+		ChatNotifier.Listener listener = chatTransactionData -> onNotify(session, chatTransactionData, address, previousOutput);
+		ChatNotifier.getInstance().register(session, listener);
+
+		this.onNotify(session, null, address, previousOutput);
+	}
+
+	@OnWebSocketClose
+	public void onWebSocketClose(Session session, int statusCode, String reason) {
+		ChatNotifier.getInstance().deregister(session);
+	}
+
+	@OnWebSocketError
+	public void onWebSocketError(Session session, Throwable throwable) {
+	}
+
+	@OnWebSocketMessage
+	public void onWebSocketMessage(Session session, String message) {
+	}
+
+	private void onNotify(Session session, ChatTransactionData chatTransactionData, String ourAddress, AtomicReference<String> previousOutput) {
+		// If CHAT has a recipient (i.e. direct message, not group-based) and we're neither sender nor recipient, then it's of no interest
+		if (chatTransactionData != null) {
+			String recipient = chatTransactionData.getRecipient();
+
+			if (recipient != null && (!recipient.equals(ourAddress) && !chatTransactionData.getSender().equals(ourAddress)))
+				return;
+		}
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			ActiveChats activeChats = repository.getChatRepository().getActiveChats(ourAddress);
+
+			StringWriter stringWriter = new StringWriter();
+
+			this.marshall(stringWriter, activeChats);
+
+			// Only output if something has changed
+			String output = stringWriter.toString();
+			if (output.equals(previousOutput.get()))
+				return;
+
+			previousOutput.set(output);
+			session.getRemote().sendStringByFuture(output);
+		} catch (DataException | IOException | WebSocketException e) {
+			// No output this time?
+		}
+	}
+
+}

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

@@ -0,0 +1,74 @@
+package org.qortal.api.websocket;
+
+import java.io.IOException;
+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;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+
+@WebSocket
+@SuppressWarnings("serial")
+public class AdminStatusWebSocket extends WebSocketServlet implements ApiWebSocket {
+
+	@Override
+	public void configure(WebSocketServletFactory factory) {
+		factory.register(AdminStatusWebSocket.class);
+	}
+
+	@OnWebSocketConnect
+	public void onWebSocketConnect(Session session) {
+		AtomicReference<String> previousOutput = new AtomicReference<>(null);
+
+		StatusNotifier.Listener listener = timestamp -> onNotify(session, previousOutput);
+		StatusNotifier.getInstance().register(session, listener);
+
+		this.onNotify(session, previousOutput);
+	}
+
+	@OnWebSocketClose
+	public void onWebSocketClose(Session session, int statusCode, String reason) {
+		StatusNotifier.getInstance().deregister(session);
+	}
+
+	@OnWebSocketError
+	public void onWebSocketError(Session session, Throwable throwable) {
+	}
+
+	@OnWebSocketMessage
+	public void onWebSocketMessage(Session session, String message) {
+	}
+
+	private void onNotify(Session session,AtomicReference<String> previousOutput) {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			NodeStatus nodeStatus = new NodeStatus();
+
+			StringWriter stringWriter = new StringWriter();
+
+			this.marshall(stringWriter, nodeStatus);
+
+			// Only output if something has changed
+			String output = stringWriter.toString();
+			if (output.equals(previousOutput.get()))
+				return;
+
+			previousOutput.set(output);
+			session.getRemote().sendStringByFuture(output);
+		} catch (DataException | IOException | WebSocketException e) {
+			// No output this time?
+		}
+	}
+
+}

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

@@ -0,0 +1,95 @@
+package org.qortal.api.websocket;
+
+import java.io.IOException;
+import java.io.StringWriter;
+import java.io.Writer;
+import java.util.Collection;
+import java.util.Map;
+
+import javax.xml.bind.JAXBContext;
+import javax.xml.bind.JAXBException;
+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.persistence.jaxb.JAXBContextFactory;
+import org.eclipse.persistence.jaxb.MarshallerProperties;
+import org.qortal.api.ApiError;
+import org.qortal.api.ApiErrorRoot;
+
+interface ApiWebSocket {
+
+	default String getPathInfo(Session session) {
+		ServletUpgradeRequest upgradeRequest = (ServletUpgradeRequest) session.getUpgradeRequest();
+		return upgradeRequest.getHttpServletRequest().getPathInfo();
+	}
+
+	default Map<String, String> getPathParams(Session session, String pathSpec) {
+		UriTemplatePathSpec uriTemplatePathSpec = new UriTemplatePathSpec(pathSpec);
+		return uriTemplatePathSpec.getPathParams(this.getPathInfo(session));
+	}
+
+	default void sendError(Session session, ApiError apiError) {
+		ApiErrorRoot apiErrorRoot = new ApiErrorRoot();
+		apiErrorRoot.setApiError(apiError);
+
+		StringWriter stringWriter = new StringWriter();
+		try {
+			marshall(stringWriter, apiErrorRoot);
+			session.getRemote().sendString(stringWriter.toString());
+		} catch (IOException e) {
+			// Remote end probably closed
+		}
+	}
+
+	default void marshall(Writer writer, Object object) throws IOException {
+		Marshaller marshaller = createMarshaller(object.getClass());
+
+		try {
+			marshaller.marshal(object, writer);
+		} catch (JAXBException e) {
+			throw new IOException("Unable to create marshall object for websocket", e);
+		}
+	}
+
+	default void marshall(Writer writer, Collection<?> collection) throws IOException {
+		// If collection is empty then we're returning "[]" anyway
+		if (collection.isEmpty()) {
+			writer.append("[]");
+			return;
+		}
+
+		// Grab an entry from collection so we can determine type
+		Object entry = collection.iterator().next();
+
+		Marshaller marshaller = createMarshaller(entry.getClass());
+
+		try {
+			marshaller.marshal(collection, writer);
+		} catch (JAXBException e) {
+			throw new IOException("Unable to create marshall object for websocket", e);
+		}
+	}
+
+	private static Marshaller createMarshaller(Class<?> objectClass) {
+		try {
+			// Create JAXB context aware of object's class
+			JAXBContext jc = JAXBContextFactory.createContext(new Class[] { objectClass }, null);
+
+			// Create marshaller
+			Marshaller marshaller = jc.createMarshaller();
+
+			// Set the marshaller media type to JSON
+			marshaller.setProperty(MarshallerProperties.MEDIA_TYPE, "application/json");
+
+			// Tell marshaller not to include JSON root element in the output
+			marshaller.setProperty(MarshallerProperties.JSON_INCLUDE_ROOT, false);
+
+			return marshaller;
+		} catch (JAXBException e) {
+			throw new RuntimeException("Unable to create websocket marshaller", e);
+		}
+	}
+
+}

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

@@ -0,0 +1,122 @@
+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.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+import org.qortal.utils.Base58;
+
+@WebSocket
+@SuppressWarnings("serial")
+public class BlocksWebSocket extends WebSocketServlet implements ApiWebSocket {
+
+	@Override
+	public void configure(WebSocketServletFactory factory) {
+		factory.register(BlocksWebSocket.class);
+	}
+
+	@OnWebSocketConnect
+	public void onWebSocketConnect(Session session) {
+		BlockNotifier.Listener listener = blockInfo -> onNotify(session, blockInfo);
+		BlockNotifier.getInstance().register(session, listener);
+	}
+
+	@OnWebSocketClose
+	public void onWebSocketClose(Session session, int statusCode, String reason) {
+		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
+		if (message.length() > 128) {
+			// Try base58 block signature
+			byte[] signature;
+
+			try {
+				signature = Base58.decode(message);
+			} catch (NumberFormatException e) {
+				sendError(session, ApiError.INVALID_SIGNATURE);
+				return;
+			}
+
+			try (final Repository repository = RepositoryManager.getRepository()) {
+				int height = repository.getBlockRepository().getHeightFromSignature(signature);
+				if (height == 0) {
+					sendError(session, ApiError.BLOCK_UNKNOWN);
+					return;
+				}
+
+				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);
+			}
+
+			return;
+		}
+
+		if (message.length() > 10)
+			// Bigger than max integer value, so probably a ping - silently ignore
+			return;
+
+		// Try integer
+		int height;
+
+		try {
+			height = Integer.parseInt(message);
+		} catch (NumberFormatException e) {
+			sendError(session, ApiError.INVALID_HEIGHT);
+			return;
+		}
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			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);
+		}
+	}
+
+	private void onNotify(Session session, BlockInfo blockInfo) {
+		StringWriter stringWriter = new StringWriter();
+
+		try {
+			this.marshall(stringWriter, blockInfo);
+
+			session.getRemote().sendStringByFuture(stringWriter.toString());
+		} catch (IOException | WebSocketException e) {
+			// No output this time
+		}
+	}
+
+}

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

@@ -0,0 +1,153 @@
+package org.qortal.api.websocket;
+
+import java.io.IOException;
+import java.io.StringWriter;
+import java.util.Arrays;
+import java.util.Collections;
+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;
+import org.qortal.data.transaction.ChatTransactionData;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+
+@WebSocket
+@SuppressWarnings("serial")
+public class ChatMessagesWebSocket extends WebSocketServlet implements ApiWebSocket {
+
+	@Override
+	public void configure(WebSocketServletFactory factory) {
+		factory.register(ChatMessagesWebSocket.class);
+	}
+
+	@OnWebSocketConnect
+	public void onWebSocketConnect(Session session) {
+		Map<String, List<String>> queryParams = session.getUpgradeRequest().getParameterMap();
+
+		List<String> txGroupIds = queryParams.get("txGroupId");
+		if (txGroupIds != null && txGroupIds.size() == 1) {
+			int txGroupId = Integer.parseInt(txGroupIds.get(0));
+
+			try (final Repository repository = RepositoryManager.getRepository()) {
+				List<ChatMessage> chatMessages = repository.getChatRepository().getMessagesMatchingCriteria(
+						null,
+						null,
+						txGroupId,
+						null,
+						null, null, null);
+
+				sendMessages(session, chatMessages);
+			} catch (DataException e) {
+				// Not a good start
+				session.close(4001, "Couldn't fetch initial messages from repository");
+				return;
+			}
+
+			ChatNotifier.Listener listener = chatTransactionData -> onNotify(session, chatTransactionData, txGroupId);
+			ChatNotifier.getInstance().register(session, listener);
+
+			return;
+		}
+
+		List<String> involvingAddresses = queryParams.get("involving");
+		if (involvingAddresses == null || involvingAddresses.size() != 2) {
+			session.close(4001, "invalid criteria");
+			return;
+		}
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			List<ChatMessage> chatMessages = repository.getChatRepository().getMessagesMatchingCriteria(
+					null,
+					null,
+					null,
+					involvingAddresses,
+					null, null, null);
+
+			sendMessages(session, chatMessages);
+		} catch (DataException e) {
+			// Not a good start
+			session.close(4001, "Couldn't fetch initial messages from repository");
+			return;
+		}
+
+		ChatNotifier.Listener listener = chatTransactionData -> onNotify(session, chatTransactionData, involvingAddresses);
+		ChatNotifier.getInstance().register(session, listener);
+	}
+
+	@OnWebSocketClose
+	public void onWebSocketClose(Session session, int statusCode, String reason) {
+		ChatNotifier.getInstance().deregister(session);
+	}
+
+	@OnWebSocketError
+	public void onWebSocketError(Session session, Throwable throwable) {
+	}
+
+	@OnWebSocketMessage
+	public void onWebSocketMessage(Session session, String message) {
+	}
+
+	private void onNotify(Session session, ChatTransactionData chatTransactionData, int txGroupId) {
+		if (chatTransactionData == null)
+			// There has been a group-membership change, but we're not interested
+			return;
+
+		// We only want group-based messages with our txGroupId
+		if (chatTransactionData.getRecipient() != null || chatTransactionData.getTxGroupId() != txGroupId)
+			return;
+
+		sendChat(session, chatTransactionData);
+	}
+
+	private void onNotify(Session session, ChatTransactionData chatTransactionData, List<String> involvingAddresses) {
+		// We only want direct/non-group messages where sender/recipient match our addresses
+		String recipient = chatTransactionData.getRecipient();
+		if (recipient == null)
+			return;
+
+		List<String> transactionAddresses = Arrays.asList(recipient, chatTransactionData.getSender());
+
+		if (!transactionAddresses.containsAll(involvingAddresses))
+			return;
+
+		sendChat(session, chatTransactionData);
+	}
+
+	private void sendMessages(Session session, List<ChatMessage> chatMessages) {
+		StringWriter stringWriter = new StringWriter();
+
+		try {
+			this.marshall(stringWriter, chatMessages);
+
+			session.getRemote().sendStringByFuture(stringWriter.toString());
+		} catch (IOException | WebSocketException e) {
+			// No output this time?
+		}
+	}
+
+	private void sendChat(Session session, ChatTransactionData chatTransactionData) {
+		// Convert ChatTransactionData to ChatMessage
+		ChatMessage chatMessage;
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			chatMessage = repository.getChatRepository().toChatMessage(chatTransactionData);
+		} catch (DataException e) {
+			// No output this time?
+			return;
+		}
+
+		sendMessages(session, Collections.singletonList(chatMessage));
+	}
+
+}

src/main/java/org/qortal/asset/Asset.java

@@ -1,11 +1,13 @@
 package org.qortal.asset;
 
+import org.qortal.crypto.Crypto;
 import org.qortal.data.asset.AssetData;
 import org.qortal.data.transaction.IssueAssetTransactionData;
 import org.qortal.data.transaction.TransactionData;
 import org.qortal.data.transaction.UpdateAssetTransactionData;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
+import org.qortal.utils.Amounts;
 
 public class Asset {
 
@@ -21,12 +23,12 @@ public class Asset {
 
 	// Other useful constants
 
-	public static final int MAX_NAME_SIZE = 400;
+	public static final int MIN_NAME_SIZE = 3;
+	public static final int MAX_NAME_SIZE = 40;
 	public static final int MAX_DESCRIPTION_SIZE = 4000;
 	public static final int MAX_DATA_SIZE = 400000;
 
-	public static final long MAX_DIVISIBLE_QUANTITY = 10_000_000_000L; // but also to 8 decimal places
-	public static final long MAX_INDIVISIBLE_QUANTITY = 1_000_000_000_000_000_000L;
+	public static final long MAX_QUANTITY = 10_000_000_000L * Amounts.MULTIPLIER; // but also to 8 decimal places
 
 	// Properties
 	private Repository repository;
@@ -42,12 +44,14 @@ public class Asset {
 	public Asset(Repository repository, IssueAssetTransactionData issueAssetTransactionData) {
 		this.repository = repository;
 
+		String ownerAddress = Crypto.toAddress(issueAssetTransactionData.getCreatorPublicKey());
+
 		// NOTE: transaction's reference is used to look up newly assigned assetID on creation!
-		this.assetData = new AssetData(issueAssetTransactionData.getOwner(), issueAssetTransactionData.getAssetName(),
+		this.assetData = new AssetData(ownerAddress, issueAssetTransactionData.getAssetName(),
 				issueAssetTransactionData.getDescription(), issueAssetTransactionData.getQuantity(),
-				issueAssetTransactionData.getIsDivisible(), issueAssetTransactionData.getData(),
-				issueAssetTransactionData.getIsUnspendable(),
-				issueAssetTransactionData.getTxGroupId(), issueAssetTransactionData.getSignature());
+				issueAssetTransactionData.isDivisible(), issueAssetTransactionData.getData(),
+				issueAssetTransactionData.isUnspendable(), issueAssetTransactionData.getTxGroupId(),
+				issueAssetTransactionData.getSignature(), issueAssetTransactionData.getReducedAssetName());
 	}
 
 	public Asset(Repository repository, long assetId) throws DataException {
@@ -118,10 +122,11 @@ public class Asset {
 				throw new IllegalStateException("Missing referenced transaction when orphaning UPDATE_ASSET");
 
 			switch (previousTransactionData.getType()) {
-				case ISSUE_ASSET:
+				case ISSUE_ASSET: {
 					IssueAssetTransactionData previousIssueAssetTransactionData = (IssueAssetTransactionData) previousTransactionData;
 
-					this.assetData.setOwner(previousIssueAssetTransactionData.getOwner());
+					String ownerAddress = Crypto.toAddress(previousIssueAssetTransactionData.getCreatorPublicKey());
+					this.assetData.setOwner(ownerAddress);
 
 					if (needDescription) {
 						this.assetData.setDescription(previousIssueAssetTransactionData.getDescription());
@@ -133,8 +138,9 @@ public class Asset {
 						needData = false;
 					}
 					break;
+				}
 
-				case UPDATE_ASSET:
+				case UPDATE_ASSET: {
 					UpdateAssetTransactionData previousUpdateAssetTransactionData = (UpdateAssetTransactionData) previousTransactionData;
 
 					this.assetData.setOwner(previousUpdateAssetTransactionData.getNewOwner());
@@ -152,7 +158,9 @@ public class Asset {
 					// Get signature for previous transaction in chain, just in case we need it
 					if (needDescription || needData)
 						previousTransactionSignature = previousUpdateAssetTransactionData.getOrphanReference();
+
 					break;
+				}
 
 				default:
 					throw new IllegalStateException("Invalid referenced transaction when orphaning UPDATE_ASSET");

src/main/java/org/qortal/asset/Order.java

@@ -1,8 +1,8 @@
 package org.qortal.asset;
 
-import java.math.BigDecimal;
+import static org.qortal.utils.Amounts.prettyAmount;
+
 import java.math.BigInteger;
-import java.math.RoundingMode;
 import java.util.Arrays;
 import java.util.List;
 
@@ -11,13 +11,12 @@ import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.qortal.account.Account;
 import org.qortal.account.PublicKeyAccount;
-import org.qortal.block.BlockChain;
 import org.qortal.data.asset.AssetData;
 import org.qortal.data.asset.OrderData;
 import org.qortal.data.asset.TradeData;
-import org.qortal.repository.AssetRepository;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
+import org.qortal.utils.Amounts;
 import org.qortal.utils.Base58;
 
 public class Order {
@@ -29,9 +28,11 @@ public class Order {
 	private OrderData orderData;
 
 	// Used quite a bit
-	private final boolean isOurOrderNewPricing;
 	private final long haveAssetId;
 	private final long wantAssetId;
+	private final boolean isAmountInWantAsset;
+	private final BigInteger orderAmount;
+	private final BigInteger orderPrice;
 
 	/** Cache of price-pair units e.g. QORT/GOLD, but use getPricePair() instead! */
 	private String cachedPricePair;
@@ -47,9 +48,12 @@ public class Order {
 		this.repository = repository;
 		this.orderData = orderData;
 
-		this.isOurOrderNewPricing = this.orderData.getTimestamp() >= BlockChain.getInstance().getNewAssetPricingTimestamp();
 		this.haveAssetId = this.orderData.getHaveAssetId();
 		this.wantAssetId = this.orderData.getWantAssetId();
+		this.isAmountInWantAsset = haveAssetId < wantAssetId;
+
+		this.orderAmount = BigInteger.valueOf(this.orderData.getAmount());
+		this.orderPrice = BigInteger.valueOf(this.orderData.getPrice());
 	}
 
 	// Getters/Setters
@@ -60,16 +64,16 @@ public class Order {
 
 	// More information
 
-	public static BigDecimal getAmountLeft(OrderData orderData) {
-		return orderData.getAmount().subtract(orderData.getFulfilled());
+	public static long getAmountLeft(OrderData orderData) {
+		return orderData.getAmount() - orderData.getFulfilled();
 	}
 
-	public BigDecimal getAmountLeft() {
+	public long getAmountLeft() {
 		return Order.getAmountLeft(this.orderData);
 	}
 
 	public static boolean isFulfilled(OrderData orderData) {
-		return orderData.getFulfilled().compareTo(orderData.getAmount()) == 0;
+		return orderData.getFulfilled() == orderData.getAmount();
 	}
 
 	public boolean isFulfilled() {
@@ -86,13 +90,10 @@ public class Order {
 	 * <p>
 	 * @return granularity of matched-amount
 	 */
-	public static BigDecimal calculateAmountGranularity(boolean isAmountAssetDivisible, boolean isReturnAssetDivisible, BigDecimal price) {
-		// Multiplier to scale BigDecimal fractional amounts into integer domain
-		BigInteger multiplier = BigInteger.valueOf(1_0000_0000L);
-
+	public static long calculateAmountGranularity(boolean isAmountAssetDivisible, boolean isReturnAssetDivisible, long price) {
 		// Calculate the minimum increment for matched-amount using greatest-common-divisor
-		BigInteger returnAmount = multiplier; // 1 unit (* multiplier)
-		BigInteger matchedAmount = price.movePointRight(8).toBigInteger();
+		BigInteger returnAmount = Amounts.MULTIPLIER_BI; // 1 unit * multiplier
+		BigInteger matchedAmount = BigInteger.valueOf(price);
 
 		BigInteger gcd = returnAmount.gcd(matchedAmount);
 		returnAmount = returnAmount.divide(gcd);
@@ -100,20 +101,20 @@ public class Order {
 
 		// Calculate GCD in combination with divisibility
 		if (isAmountAssetDivisible)
-			returnAmount = returnAmount.multiply(multiplier);
+			returnAmount = returnAmount.multiply(Amounts.MULTIPLIER_BI);
 
 		if (isReturnAssetDivisible)
-			matchedAmount = matchedAmount.multiply(multiplier);
+			matchedAmount = matchedAmount.multiply(Amounts.MULTIPLIER_BI);
 
 		gcd = returnAmount.gcd(matchedAmount);
 
 		// Calculate the granularity at which we have to buy
-		BigDecimal granularity = new BigDecimal(returnAmount.divide(gcd));
+		BigInteger granularity = returnAmount.multiply(Amounts.MULTIPLIER_BI).divide(gcd);
 		if (isAmountAssetDivisible)
-			granularity = granularity.movePointLeft(8);
+			granularity = granularity.divide(Amounts.MULTIPLIER_BI);
 
 		// Return
-		return granularity;
+		return granularity.longValue();
 	}
 
 	/**
@@ -130,7 +131,7 @@ public class Order {
 
 	/** Calculate price pair. (e.g. QORT/GOLD)
 	 * <p>
-	 * Under 'new' pricing scheme, lowest-assetID asset is first,
+	 * Lowest-assetID asset is first,
 	 * so if QORT has assetID 0 and GOLD has assetID 10, then
 	 * the pricing pair is QORT/GOLD.
 	 * <p>
@@ -141,32 +142,32 @@ public class Order {
 		AssetData haveAssetData = getHaveAsset();
 		AssetData wantAssetData = getWantAsset();
 
-		if (isOurOrderNewPricing && haveAssetId > wantAssetId)
+		if (haveAssetId > wantAssetId)
 			cachedPricePair = wantAssetData.getName() + "/" + haveAssetData.getName();
 		else
 			cachedPricePair = haveAssetData.getName() + "/" + wantAssetData.getName();
 	}
 
 	/** Returns amount of have-asset to remove from order's creator's balance on placing this order. */
-	private BigDecimal calcHaveAssetCommittment() {
-		BigDecimal committedCost = this.orderData.getAmount();
+	private long calcHaveAssetCommittment() {
+		// Simple case: amount is in have asset
+		if (!this.isAmountInWantAsset)
+			return this.orderData.getAmount();
 
-		// If 'new' pricing and "amount" is in want-asset then we need to convert
-		if (isOurOrderNewPricing && haveAssetId < wantAssetId)
-			committedCost = committedCost.multiply(this.orderData.getPrice()).setScale(8, RoundingMode.HALF_UP);
+		return Amounts.roundUpScaledMultiply(this.orderAmount, this.orderPrice);
+	}
 
-		return committedCost;
+	private long calcHaveAssetRefund(long amount) {
+		// Simple case: amount is in have asset
+		if (!this.isAmountInWantAsset)
+			return amount;
+
+		return Amounts.roundUpScaledMultiply(BigInteger.valueOf(amount), this.orderPrice);
 	}
 
 	/** Returns amount of remaining have-asset to refund to order's creator's balance on cancelling this order. */
-	private BigDecimal calcHaveAssetRefund() {
-		BigDecimal refund = getAmountLeft();
-
-		// If 'new' pricing and "amount" is in want-asset then we need to convert
-		if (isOurOrderNewPricing && haveAssetId < wantAssetId)
-			refund = refund.multiply(this.orderData.getPrice()).setScale(8, RoundingMode.HALF_UP);
-
-		return refund;
+	private long calcHaveAssetRefund() {
+		return calcHaveAssetRefund(getAmountLeft());
 	}
 
 	// Navigation
@@ -192,27 +193,19 @@ public class Order {
 	/**
 	 * Returns AssetData for asset in effect for "amount" field.
 	 * <p>
-	 * For 'old' pricing, this is the have-asset.<br>
-	 * For 'new' pricing, this is the asset with highest assetID.
+	 * This is the asset with highest assetID.
 	 */
 	public AssetData getAmountAsset() throws DataException {
-		if (isOurOrderNewPricing && wantAssetId > haveAssetId)
-			return getWantAsset();
-		else
-			return getHaveAsset();
+		return (wantAssetId > haveAssetId) ? getWantAsset() : getHaveAsset();
 	}
 
 	/**
 	 * Returns AssetData for other (return) asset traded.
 	 * <p>
-	 * For 'old' pricing, this is the want-asset.<br>
-	 * For 'new' pricing, this is the asset with lowest assetID.
+	 * This is the asset with lowest assetID.
 	 */
 	public AssetData getReturnAsset() throws DataException {
-		if (isOurOrderNewPricing && haveAssetId < wantAssetId)
-			return getHaveAsset();
-		else
-			return getWantAsset();
+		return (haveAssetId < wantAssetId) ? getHaveAsset() : getWantAsset();
 	}
 
 	// Processing
@@ -227,8 +220,6 @@ public class Order {
 
 		// NOTE: the following values are specific to passed orderData, not the same as class instance values!
 
-		final boolean isOrderNewAssetPricing = orderData.getTimestamp() >= BlockChain.getInstance().getNewAssetPricingTimestamp();
-
 		// Cached for readability
 		final long _haveAssetId = orderData.getHaveAssetId();
 		final long _wantAssetId = orderData.getWantAssetId();
@@ -236,43 +227,36 @@ public class Order {
 		final AssetData haveAssetData = this.repository.getAssetRepository().fromAssetId(_haveAssetId);
 		final AssetData wantAssetData = this.repository.getAssetRepository().fromAssetId(_wantAssetId);
 
-		final long amountAssetId = (isOurOrderNewPricing && _wantAssetId > _haveAssetId) ? _wantAssetId : _haveAssetId;
-		final long returnAssetId = (isOurOrderNewPricing && _haveAssetId < _wantAssetId) ? _haveAssetId : _wantAssetId;
+		final long amountAssetId = (_wantAssetId > _haveAssetId) ? _wantAssetId : _haveAssetId;
+		final long returnAssetId = (_haveAssetId < _wantAssetId) ? _haveAssetId : _wantAssetId;
 
 		final AssetData amountAssetData = this.repository.getAssetRepository().fromAssetId(amountAssetId);
 		final AssetData returnAssetData = this.repository.getAssetRepository().fromAssetId(returnAssetId);
 
-		LOGGER.debug(String.format("%s %s", orderPrefix, Base58.encode(orderData.getOrderId())));
+		LOGGER.debug(() -> String.format("%s %s", orderPrefix, Base58.encode(orderData.getOrderId())));
 
-		LOGGER.trace(String.format("%s have %s, want %s. '%s' pricing scheme.", weThey, haveAssetData.getName(), wantAssetData.getName(), isOrderNewAssetPricing ? "new" : "old"));
+		LOGGER.trace(() -> String.format("%s have %s, want %s.", weThey, haveAssetData.getName(), wantAssetData.getName()));
 
-		LOGGER.trace(String.format("%s amount: %s (ordered) - %s (fulfilled) = %s %s left", ourTheir,
-				orderData.getAmount().stripTrailingZeros().toPlainString(),
-				orderData.getFulfilled().stripTrailingZeros().toPlainString(),
-				Order.getAmountLeft(orderData).stripTrailingZeros().toPlainString(),
+		LOGGER.trace(() -> String.format("%s amount: %s (ordered) - %s (fulfilled) = %s %s left", ourTheir,
+				prettyAmount(orderData.getAmount()),
+				prettyAmount(orderData.getFulfilled()),
+				prettyAmount(Order.getAmountLeft(orderData)),
 				amountAssetData.getName()));
 
-		BigDecimal maxReturnAmount = Order.getAmountLeft(orderData).multiply(orderData.getPrice()).setScale(8, RoundingMode.HALF_UP);
+		long maxReturnAmount = Amounts.roundUpScaledMultiply(Order.getAmountLeft(orderData), orderData.getPrice());
+		String pricePair = getPricePair();
 
-		LOGGER.trace(String.format("%s price: %s %s (%s %s tradable)", ourTheir,
-				orderData.getPrice().toPlainString(), getPricePair(),
-				maxReturnAmount.stripTrailingZeros().toPlainString(), returnAssetData.getName()));
+		LOGGER.trace(() -> String.format("%s price: %s %s (%s %s tradable)", ourTheir,
+				prettyAmount(orderData.getPrice()),
+				pricePair,
+				prettyAmount(maxReturnAmount),
+				returnAssetData.getName()));
 	}
 
 	public void process() throws DataException {
-		AssetRepository assetRepository = this.repository.getAssetRepository();
-
-		AssetData haveAssetData = getHaveAsset();
-		AssetData wantAssetData = getWantAsset();
-
-		/** The asset while working out amount that matches. */
-		AssetData matchingAssetData = isOurOrderNewPricing ? getAmountAsset() : wantAssetData;
-		/** The return asset traded if trade completes. */
-		AssetData returnAssetData = isOurOrderNewPricing ? getReturnAsset() : haveAssetData;
-
 		// Subtract have-asset from creator
 		Account creator = new PublicKeyAccount(this.repository, this.orderData.getCreatorPublicKey());
-		creator.setConfirmedBalance(haveAssetId, creator.getConfirmedBalance(haveAssetId).subtract(this.calcHaveAssetCommittment()));
+		creator.modifyAssetBalance(haveAssetId, - this.calcHaveAssetCommittment());
 
 		// Save this order into repository so it's available for matching, possibly by itself
 		this.repository.getAssetRepository().save(this.orderData);
@@ -281,36 +265,28 @@ public class Order {
 
 		// Fetch corresponding open orders that might potentially match, hence reversed want/have assetIDs.
 		// Returned orders are sorted with lowest "price" first.
-		List<OrderData> orders = assetRepository.getOpenOrdersForTrading(wantAssetId, haveAssetId, isOurOrderNewPricing ? this.orderData.getPrice() : null);
-		LOGGER.trace("Open orders fetched from repository: " + orders.size());
+		List<OrderData> orders = this.repository.getAssetRepository().getOpenOrdersForTrading(wantAssetId, haveAssetId, this.orderData.getPrice());
+		LOGGER.trace(() -> String.format("Open orders fetched from repository: %d", orders.size()));
 
 		if (orders.isEmpty())
 			return;
 
+		matchOrders(orders);
+	}
+
+	private void matchOrders(List<OrderData> orders) throws DataException {
+		AssetData haveAssetData = getHaveAsset();
+		AssetData wantAssetData = getWantAsset();
+
+		/** The asset while working out amount that matches. */
+		AssetData matchingAssetData = getAmountAsset();
+		/** The return asset traded if trade completes. */
+		AssetData returnAssetData = getReturnAsset();
+
 		// Attempt to match orders
 
 		/*
-		 * Potential matching order example ("old"):
-		 * 
-		 * Our order:
-		 * haveAssetId=[GOLD], wantAssetId=0 (QORT), amount=40 (GOLD), price=486 (QORT/GOLD)
-		 * This translates to "we have 40 GOLD and want QORT at a price of 486 QORT per GOLD"
-		 * If our order matched, we'd end up with 40 * 486 = 19,440 QORT.
-		 * 
-		 * Their order:
-		 * haveAssetId=0 (QORT), wantAssetId=[GOLD], amount=20,000 (QORT), price=0.00205761 (GOLD/QORT)
-		 * This translates to "they have 20,000 QORT and want GOLD at a price of 0.00205761 GOLD per QORT"
-		 * 
-		 * Their price, converted into 'our' units of QORT/GOLD, is: 1 / 0.00205761 = 486.00074844 QORT/GOLD.
-		 * This is better than our requested 486 QORT/GOLD so this order matches.
-		 * 
-		 * Using their price, we end up with 40 * 486.00074844 = 19440.02993760 QORT. They end up with 40 GOLD.
-		 * 
-		 * If their order had 19,440 QORT left, only 19,440 * 0.00205761 = 39.99993840 GOLD would be traded.
-		 */
-
-		/*
-		 * Potential matching order example ("new"):
+		 * Potential matching order example:
 		 * 
 		 * Our order:
 		 * haveAssetId=[GOLD], wantAssetId=0 (QORT), amount=40 (GOLD), price=486 (QORT/GOLD)
@@ -328,129 +304,107 @@ public class Order {
 		 * If their order only had 36 GOLD left, only 36 * 486.00074844 = 17496.02694384 QORT would be traded.
 		 */
 
-		BigDecimal ourPrice = this.orderData.getPrice();
+		long ourPrice = this.orderData.getPrice();
+		String pricePair = getPricePair();
 
 		for (OrderData theirOrderData : orders) {
 			logOrder("Considering order", false, theirOrderData);
 
-			// Not used:
-			// boolean isTheirOrderNewAssetPricing = theirOrderData.getTimestamp() >= BlockChain.getInstance().getNewAssetPricingTimestamp();
-
 			// Determine their order price
-			BigDecimal theirPrice;
-
-			if (isOurOrderNewPricing) {
-				// Pricing units are the same way round for both orders, so no conversion needed.
-				// Orders under 'old' pricing have been converted during repository update.
-				theirPrice = theirOrderData.getPrice();
-				LOGGER.trace(String.format("Their price: %s %s", theirPrice.toPlainString(), getPricePair()));
-			} else {
-				// If our order is 'old' pricing then all other existing orders must be 'old' pricing too
-				// Their order pricing will be inverted, so convert
-				theirPrice = BigDecimal.ONE.setScale(8).divide(theirOrderData.getPrice(), RoundingMode.DOWN);
-				LOGGER.trace(String.format("Their price: %s %s per %s", theirPrice.toPlainString(), wantAssetData.getName(), haveAssetData.getName()));
-			}
+			long theirPrice = theirOrderData.getPrice();
+			LOGGER.trace(() -> String.format("Their price: %s %s", prettyAmount(theirPrice), pricePair));
 
 			// If their price is worse than what we're willing to accept then we're done as prices only get worse as we iterate through list of orders
-			if (isOurOrderNewPricing) {
-				if (haveAssetId < wantAssetId && theirPrice.compareTo(ourPrice) > 0)
-					break;
-				if (haveAssetId > wantAssetId && theirPrice.compareTo(ourPrice) < 0)
-					break;
-			} else {
-				// 'old' pricing scheme
-				if (theirPrice.compareTo(ourPrice) < 0)
-					break;
-			}
+			if ((haveAssetId < wantAssetId && theirPrice > ourPrice) || (haveAssetId > wantAssetId && theirPrice < ourPrice))
+				break;
 
-			// Calculate how much we could buy at their price.
-			BigDecimal ourMaxAmount;
-			if (isOurOrderNewPricing)
-				// In 'new' pricing scheme, "amount" is expressed in terms of asset with highest assetID
-				ourMaxAmount = this.getAmountLeft();
-			else
-				// In 'old' pricing scheme, "amount" is expressed in terms of our want-asset.
-				ourMaxAmount = this.getAmountLeft().multiply(theirPrice).setScale(8, RoundingMode.DOWN);
-			LOGGER.trace("ourMaxAmount (max we could trade at their price): " + ourMaxAmount.stripTrailingZeros().toPlainString() + " " + matchingAssetData.getName());
+			// Calculate how much we could buy at their price, "amount" is expressed in terms of asset with highest assetID.
+			long ourMaxAmount = this.getAmountLeft();
+			LOGGER.trace(() -> String.format("ourMaxAmount (max we could trade at their price): %s %s", prettyAmount(ourMaxAmount), matchingAssetData.getName()));
 
 			// How much is remaining available in their order.
-			BigDecimal theirAmountLeft = Order.getAmountLeft(theirOrderData);
-			LOGGER.trace("theirAmountLeft (max amount remaining in their order): " + theirAmountLeft.stripTrailingZeros().toPlainString() + " " + matchingAssetData.getName());
+			long theirAmountLeft = Order.getAmountLeft(theirOrderData);
+			LOGGER.trace(() -> String.format("theirAmountLeft (max amount remaining in their order): %s %s", prettyAmount(theirAmountLeft), matchingAssetData.getName()));
 
 			// So matchable want-asset amount is the minimum of above two values
-			BigDecimal matchedAmount = ourMaxAmount.min(theirAmountLeft);
-			LOGGER.trace("matchedAmount: " + matchedAmount.stripTrailingZeros().toPlainString() + " " + matchingAssetData.getName());
+			long interimMatchedAmount = Math.min(ourMaxAmount, theirAmountLeft);
+			LOGGER.trace(() -> String.format("matchedAmount: %s %s", prettyAmount(interimMatchedAmount), matchingAssetData.getName()));
 
 			// If we can't buy anything then try another order
-			if (matchedAmount.compareTo(BigDecimal.ZERO) <= 0)
+			if (interimMatchedAmount <= 0)
 				continue;
 
 			// Calculate amount granularity, based on price and both assets' divisibility, so that return-amount traded is a valid value (integer or to 8 d.p.)
-			BigDecimal granularity = calculateAmountGranularity(matchingAssetData.getIsDivisible(), returnAssetData.getIsDivisible(), theirOrderData.getPrice());
-			LOGGER.trace("granularity (amount granularity): " + granularity.stripTrailingZeros().toPlainString() + " " + matchingAssetData.getName());
+			long granularity = calculateAmountGranularity(matchingAssetData.isDivisible(), returnAssetData.isDivisible(), theirOrderData.getPrice());
+			LOGGER.trace(() -> String.format("granularity (amount granularity): %s %s", prettyAmount(granularity), matchingAssetData.getName()));
 
 			// Reduce matched amount (if need be) to fit granularity
-			matchedAmount = matchedAmount.subtract(matchedAmount.remainder(granularity));
-			LOGGER.trace("matchedAmount adjusted for granularity: " + matchedAmount.stripTrailingZeros().toPlainString() + " " + matchingAssetData.getName());
+			long matchedAmount = interimMatchedAmount - interimMatchedAmount % granularity;
+			LOGGER.trace(() -> String.format("matchedAmount adjusted for granularity: %s %s", prettyAmount(matchedAmount), matchingAssetData.getName()));
 
 			// If we can't buy anything then try another order
-			if (matchedAmount.compareTo(BigDecimal.ZERO) <= 0)
+			if (matchedAmount <= 0)
 				continue;
 
 			// Safety check
-			if (!matchingAssetData.getIsDivisible() && matchedAmount.stripTrailingZeros().scale() > 0) {
-				Account participant = new PublicKeyAccount(this.repository, theirOrderData.getCreatorPublicKey());
-
-				String message = String.format("Refusing to trade fractional %s [indivisible assetID %d] for %s",
-						matchedAmount.toPlainString(), matchingAssetData.getAssetId(), participant.getAddress());
-				LOGGER.error(message);
-				throw new DataException(message);
-			}
+			checkDivisibility(matchingAssetData, matchedAmount, theirOrderData);
 
 			// Trade can go ahead!
 
 			// Calculate the total cost to us, in return-asset, based on their price
-			BigDecimal returnAmountTraded = matchedAmount.multiply(theirOrderData.getPrice()).setScale(8, RoundingMode.DOWN);
-			LOGGER.trace("returnAmountTraded: " + returnAmountTraded.stripTrailingZeros().toPlainString() + " " + returnAssetData.getName());
+			long returnAmountTraded = Amounts.roundDownScaledMultiply(matchedAmount, theirOrderData.getPrice());
+			LOGGER.trace(() -> String.format("returnAmountTraded: %s %s", prettyAmount(returnAmountTraded), returnAssetData.getName()));
 
 			// Safety check
-			if (!returnAssetData.getIsDivisible() && returnAmountTraded.stripTrailingZeros().scale() > 0) {
-				String message = String.format("Refusing to trade fractional %s [indivisible assetID %d] for %s",
-						returnAmountTraded.toPlainString(), returnAssetData.getAssetId(), creator.getAddress());
-				LOGGER.error(message);
-				throw new DataException(message);
-			}
+			checkDivisibility(returnAssetData, returnAmountTraded, this.orderData);
 
-			BigDecimal tradedWantAmount = (isOurOrderNewPricing && haveAssetId > wantAssetId) ? returnAmountTraded : matchedAmount;
-			BigDecimal tradedHaveAmount = (isOurOrderNewPricing && haveAssetId > wantAssetId) ? matchedAmount : returnAmountTraded;
+			long tradedWantAmount = this.isAmountInWantAsset ? matchedAmount : returnAmountTraded;
+			long tradedHaveAmount = this.isAmountInWantAsset ? returnAmountTraded : matchedAmount;
 
-			// We also need to know how much have-asset to refund based on price improvement ('new' pricing only and only one direction applies)
-			BigDecimal haveAssetRefund = isOurOrderNewPricing && haveAssetId < wantAssetId ? ourPrice.subtract(theirPrice).abs().multiply(matchedAmount).setScale(8, RoundingMode.DOWN) : BigDecimal.ZERO;
+			// We also need to know how much have-asset to refund based on price improvement (only one direction applies)
+			long haveAssetRefund = this.isAmountInWantAsset ? Amounts.roundDownScaledMultiply(matchedAmount, Math.abs(ourPrice - theirPrice)) : 0;
 
-			LOGGER.trace(String.format("We traded %s %s (have-asset) for %s %s (want-asset), saving %s %s (have-asset)",
-					tradedHaveAmount.toPlainString(), haveAssetData.getName(),
-					tradedWantAmount.toPlainString(), wantAssetData.getName(),
-					haveAssetRefund.toPlainString(), haveAssetData.getName()));
+			LOGGER.trace(() -> String.format("We traded %s %s (have-asset) for %s %s (want-asset), saving %s %s (have-asset)",
+					prettyAmount(tradedHaveAmount), haveAssetData.getName(),
+					prettyAmount(tradedWantAmount), wantAssetData.getName(),
+					prettyAmount(haveAssetRefund), haveAssetData.getName()));
 
 			// Construct trade
 			TradeData tradeData = new TradeData(this.orderData.getOrderId(), theirOrderData.getOrderId(),
 					tradedWantAmount, tradedHaveAmount, haveAssetRefund, this.orderData.getTimestamp());
+
 			// Process trade, updating corresponding orders in repository
 			Trade trade = new Trade(this.repository, tradeData);
 			trade.process();
 
 			// Update our order in terms of fulfilment, etc. but do not save into repository as that's handled by Trade above
-			BigDecimal amountFulfilled = isOurOrderNewPricing ? matchedAmount : returnAmountTraded;
-			this.orderData.setFulfilled(this.orderData.getFulfilled().add(amountFulfilled));
-			LOGGER.trace("Updated our order's fulfilled amount to: " + this.orderData.getFulfilled().stripTrailingZeros().toPlainString() + " " + matchingAssetData.getName());
-			LOGGER.trace("Our order's amount remaining: " + this.getAmountLeft().stripTrailingZeros().toPlainString() + " " + matchingAssetData.getName());
+			long amountFulfilled = matchedAmount;
+			this.orderData.setFulfilled(this.orderData.getFulfilled() + amountFulfilled);
+			LOGGER.trace(() -> String.format("Updated our order's fulfilled amount to: %s %s", prettyAmount(this.orderData.getFulfilled()), matchingAssetData.getName()));
+			LOGGER.trace(() -> String.format("Our order's amount remaining: %s %s", prettyAmount(this.getAmountLeft()), matchingAssetData.getName()));
 
 			// Continue on to process other open orders if we still have amount left to match
-			if (this.getAmountLeft().compareTo(BigDecimal.ZERO) <= 0)
+			if (this.getAmountLeft() <= 0)
 				break;
 		}
 	}
 
+	/**
+	 * Check amount has no fractional part if asset is indivisible.
+	 * 
+	 * @throws DataException if divisibility check fails
+	 */
+	private void checkDivisibility(AssetData assetData, long amount, OrderData orderData) throws DataException {
+		if (assetData.isDivisible() || amount % Amounts.MULTIPLIER == 0)
+			// Asset is divisible or amount has no fractional part
+			return;
+
+		String message = String.format("Refusing to trade fractional %s [indivisible assetID %d] for order %s",
+				prettyAmount(amount), assetData.getAssetId(), Base58.encode(orderData.getOrderId()));
+		LOGGER.error(message);
+		throw new DataException(message);
+	}
+
 	public void orphan() throws DataException {
 		// Orphan trades that occurred as a result of this order
 		for (TradeData tradeData : getTrades())
@@ -464,7 +418,7 @@ public class Order {
 
 		// Return asset to creator
 		Account creator = new PublicKeyAccount(this.repository, this.orderData.getCreatorPublicKey());
-		creator.setConfirmedBalance(haveAssetId, creator.getConfirmedBalance(haveAssetId).add(this.calcHaveAssetCommittment()));
+		creator.modifyAssetBalance(haveAssetId, this.calcHaveAssetCommittment());
 	}
 
 	// This is called by CancelOrderTransaction so that an Order can no longer trade
@@ -474,14 +428,14 @@ public class Order {
 
 		// Update creator's balance with unfulfilled amount
 		Account creator = new PublicKeyAccount(this.repository, this.orderData.getCreatorPublicKey());
-		creator.setConfirmedBalance(haveAssetId, creator.getConfirmedBalance(haveAssetId).add(calcHaveAssetRefund()));
+		creator.modifyAssetBalance(haveAssetId, calcHaveAssetRefund());
 	}
 
 	// Opposite of cancel() above for use during orphaning
 	public void reopen() throws DataException {
 		// Update creator's balance with unfulfilled amount
 		Account creator = new PublicKeyAccount(this.repository, this.orderData.getCreatorPublicKey());
-		creator.setConfirmedBalance(haveAssetId, creator.getConfirmedBalance(haveAssetId).subtract(calcHaveAssetRefund()));
+		creator.modifyAssetBalance(haveAssetId, - calcHaveAssetRefund());
 
 		this.orderData.setIsClosed(false);
 		this.repository.getAssetRepository().save(this.orderData);

src/main/java/org/qortal/asset/Trade.java

@@ -1,10 +1,7 @@
 package org.qortal.asset;
 
-import java.math.BigDecimal;
-
 import org.qortal.account.Account;
 import org.qortal.account.PublicKeyAccount;
-import org.qortal.block.BlockChain;
 import org.qortal.data.asset.OrderData;
 import org.qortal.data.asset.TradeData;
 import org.qortal.repository.AssetRepository;
@@ -17,12 +14,11 @@ public class Trade {
 	private Repository repository;
 	private TradeData tradeData;
 
-	private boolean isNewPricing;
 	private AssetRepository assetRepository;
 
 	private OrderData initiatingOrder;
 	private OrderData targetOrder;
-	private BigDecimal newPricingFulfilled;
+	private long fulfilled;
 
 	// Constructors
 
@@ -30,7 +26,6 @@ public class Trade {
 		this.repository = repository;
 		this.tradeData = tradeData;
 
-		this.isNewPricing = this.tradeData.getTimestamp() > BlockChain.getInstance().getNewAssetPricingTimestamp();
 		this.assetRepository = this.repository.getAssetRepository();
 	}
 
@@ -43,9 +38,9 @@ public class Trade {
 		// Note: targetAmount is amount traded FROM target order
 		// Note: initiatorAmount is amount traded FROM initiating order
 
-		// Under 'new' pricing scheme, "amount" and "fulfilled" are the same asset for both orders
+		// "amount" and "fulfilled" are the same asset for both orders
 		// which is the matchedAmount in asset with highest assetID
-		this.newPricingFulfilled = (initiatingOrder.getHaveAssetId() < initiatingOrder.getWantAssetId()) ? this.tradeData.getTargetAmount() : this.tradeData.getInitiatorAmount();
+		this.fulfilled = initiatingOrder.getHaveAssetId() < initiatingOrder.getWantAssetId() ? this.tradeData.getTargetAmount() : this.tradeData.getInitiatorAmount();
 	}
 
 	public void process() throws DataException {
@@ -55,16 +50,16 @@ public class Trade {
 		// Note: targetAmount is amount traded FROM target order
 		// Note: initiatorAmount is amount traded FROM initiating order
 
-		// Update corresponding Orders on both sides of trade
 		commonPrep();
 
-		initiatingOrder.setFulfilled(initiatingOrder.getFulfilled().add(isNewPricing ? newPricingFulfilled : tradeData.getInitiatorAmount()));
+		// Update corresponding Orders on both sides of trade
+		initiatingOrder.setFulfilled(initiatingOrder.getFulfilled() + fulfilled);
 		initiatingOrder.setIsFulfilled(Order.isFulfilled(initiatingOrder));
 		// Set isClosed to true if isFulfilled now true
 		initiatingOrder.setIsClosed(initiatingOrder.getIsFulfilled());
 		assetRepository.save(initiatingOrder);
 
-		targetOrder.setFulfilled(targetOrder.getFulfilled().add(isNewPricing ? newPricingFulfilled : tradeData.getTargetAmount()));
+		targetOrder.setFulfilled(targetOrder.getFulfilled() + fulfilled);
 		targetOrder.setIsFulfilled(Order.isFulfilled(targetOrder));
 		// Set isClosed to true if isFulfilled now true
 		targetOrder.setIsClosed(targetOrder.getIsFulfilled());
@@ -72,33 +67,31 @@ public class Trade {
 
 		// Actually transfer asset balances
 		Account initiatingCreator = new PublicKeyAccount(this.repository, initiatingOrder.getCreatorPublicKey());
-		initiatingCreator.setConfirmedBalance(initiatingOrder.getWantAssetId(), initiatingCreator.getConfirmedBalance(initiatingOrder.getWantAssetId()).add(tradeData.getTargetAmount()));
+		initiatingCreator.modifyAssetBalance(initiatingOrder.getWantAssetId(), tradeData.getTargetAmount());
 
 		Account targetCreator = new PublicKeyAccount(this.repository, targetOrder.getCreatorPublicKey());
-		targetCreator.setConfirmedBalance(targetOrder.getWantAssetId(), targetCreator.getConfirmedBalance(targetOrder.getWantAssetId()).add(tradeData.getInitiatorAmount()));
+		targetCreator.modifyAssetBalance(targetOrder.getWantAssetId(), tradeData.getInitiatorAmount());
 
 		// Possible partial saving to refund to initiator
-		BigDecimal initiatorSaving = this.tradeData.getInitiatorSaving();
-		if (initiatorSaving.compareTo(BigDecimal.ZERO) > 0)
-			initiatingCreator.setConfirmedBalance(initiatingOrder.getHaveAssetId(), initiatingCreator.getConfirmedBalance(initiatingOrder.getHaveAssetId()).add(initiatorSaving));
+		long initiatorSaving = this.tradeData.getInitiatorSaving();
+		if (initiatorSaving > 0)
+			initiatingCreator.modifyAssetBalance(initiatingOrder.getHaveAssetId(), initiatorSaving);
 	}
 
 	public void orphan() throws DataException {
-		AssetRepository assetRepository = this.repository.getAssetRepository();
-
 		// Note: targetAmount is amount traded FROM target order
 		// Note: initiatorAmount is amount traded FROM initiating order
 
-		// Revert corresponding Orders on both sides of trade
 		commonPrep();
 
-		initiatingOrder.setFulfilled(initiatingOrder.getFulfilled().subtract(isNewPricing ? newPricingFulfilled : tradeData.getInitiatorAmount()));
+		// Revert corresponding Orders on both sides of trade
+		initiatingOrder.setFulfilled(initiatingOrder.getFulfilled() - fulfilled);
 		initiatingOrder.setIsFulfilled(Order.isFulfilled(initiatingOrder));
 		// Set isClosed to false if isFulfilled now false
 		initiatingOrder.setIsClosed(initiatingOrder.getIsFulfilled());
 		assetRepository.save(initiatingOrder);
 
-		targetOrder.setFulfilled(targetOrder.getFulfilled().subtract(isNewPricing ? newPricingFulfilled : tradeData.getTargetAmount()));
+		targetOrder.setFulfilled(targetOrder.getFulfilled() - fulfilled);
 		targetOrder.setIsFulfilled(Order.isFulfilled(targetOrder));
 		// Set isClosed to false if isFulfilled now false
 		targetOrder.setIsClosed(targetOrder.getIsFulfilled());
@@ -106,15 +99,15 @@ public class Trade {
 
 		// Reverse asset transfers
 		Account initiatingCreator = new PublicKeyAccount(this.repository, initiatingOrder.getCreatorPublicKey());
-		initiatingCreator.setConfirmedBalance(initiatingOrder.getWantAssetId(), initiatingCreator.getConfirmedBalance(initiatingOrder.getWantAssetId()).subtract(tradeData.getTargetAmount()));
+		initiatingCreator.modifyAssetBalance(initiatingOrder.getWantAssetId(), - tradeData.getTargetAmount());
 
 		Account targetCreator = new PublicKeyAccount(this.repository, targetOrder.getCreatorPublicKey());
-		targetCreator.setConfirmedBalance(targetOrder.getWantAssetId(), targetCreator.getConfirmedBalance(targetOrder.getWantAssetId()).subtract(tradeData.getInitiatorAmount()));
+		targetCreator.modifyAssetBalance(targetOrder.getWantAssetId(), - tradeData.getInitiatorAmount());
 
 		// Possible partial saving to claw back from  initiator
-		BigDecimal initiatorSaving = this.tradeData.getInitiatorSaving();
-		if (initiatorSaving.compareTo(BigDecimal.ZERO) > 0)
-			initiatingCreator.setConfirmedBalance(initiatingOrder.getHaveAssetId(), initiatingCreator.getConfirmedBalance(initiatingOrder.getHaveAssetId()).subtract(initiatorSaving));
+		long initiatorSaving = this.tradeData.getInitiatorSaving();
+		if (initiatorSaving > 0)
+			initiatingCreator.modifyAssetBalance(initiatingOrder.getHaveAssetId(), - initiatorSaving);
 
 		// Remove trade from repository
 		assetRepository.delete(tradeData);

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

@@ -1,11 +1,9 @@
 package org.qortal.at;
 
-import java.math.BigDecimal;
-import java.nio.ByteBuffer;
 import java.util.List;
 
 import org.ciyam.at.MachineState;
-import org.qortal.asset.Asset;
+import org.ciyam.at.Timestamp;
 import org.qortal.crypto.Crypto;
 import org.qortal.data.at.ATData;
 import org.qortal.data.at.ATStateData;
@@ -42,66 +40,27 @@ public class AT {
 		int height = this.repository.getBlockRepository().getBlockchainHeight() + 1;
 		byte[] creatorPublicKey = deployATTransactionData.getCreatorPublicKey();
 		long creation = deployATTransactionData.getTimestamp();
-
-		byte[] creationBytes = deployATTransactionData.getCreationBytes();
 		long assetId = deployATTransactionData.getAssetId();
-		short version = (short) ((creationBytes[0] & 0xff) | (creationBytes[1] << 8)); // Little-endian
 
-		if (version >= 2) {
-			MachineState machineState = new MachineState(deployATTransactionData.getCreationBytes());
+		// Just enough AT data to allow API to query initial balances, etc.
+		ATData skeletonAtData = new ATData(atAddress, creatorPublicKey, creation, assetId);
 
-			this.atData = new ATData(atAddress, creatorPublicKey, creation, machineState.version, assetId, machineState.getCodeBytes(),
-					machineState.getIsSleeping(), machineState.getSleepUntilHeight(), machineState.getIsFinished(), machineState.getHadFatalError(),
-					machineState.getIsFrozen(), machineState.getFrozenBalance());
+		long blockTimestamp = Timestamp.toLong(height, 0);
+		QortalATAPI api = new QortalATAPI(repository, skeletonAtData, blockTimestamp);
+		QortalAtLoggerFactory loggerFactory = QortalAtLoggerFactory.getInstance();
 
-			byte[] stateData = machineState.toBytes();
-			byte[] stateHash = Crypto.digest(stateData);
+		MachineState machineState = new MachineState(api, loggerFactory, deployATTransactionData.getCreationBytes());
 
-			this.atStateData = new ATStateData(atAddress, height, creation, stateData, stateHash, BigDecimal.ZERO.setScale(8));
-		} else {
-			// Legacy v1 AT
-			// We would deploy these in 'dead' state as they will never be run on Qortal
-			// but this breaks import from Qora1 so something else will have to mark them dead at hard-fork
+		byte[] codeHash = Crypto.digest(machineState.getCodeBytes());
 
-			// Extract code bytes length
-			ByteBuffer byteBuffer = ByteBuffer.wrap(deployATTransactionData.getCreationBytes());
+		this.atData = new ATData(atAddress, creatorPublicKey, creation, machineState.version, assetId, machineState.getCodeBytes(), codeHash,
+				machineState.isSleeping(), machineState.getSleepUntilHeight(), machineState.isFinished(), machineState.hadFatalError(),
+				machineState.isFrozen(), machineState.getFrozenBalance());
 
-			// v1 AT header is: version, reserved, code-pages, data-pages, call-stack-pages, user-stack-pages (all shorts)
+		byte[] stateData = machineState.toBytes();
+		byte[] stateHash = Crypto.digest(stateData);
 
-			// Number of code pages
-			short numCodePages = byteBuffer.get(2 + 2);
-
-			// Skip header and also "minimum activation amount" (long)
-			byteBuffer.position(6 * 2 + 8);
-
-			int codeLen = 0;
-
-			// Extract actual code length, stored in minimal-size form (byte, short or int)
-			if (numCodePages * 256 < 257) {
-				codeLen = byteBuffer.get() & 0xff;
-			} else if (numCodePages * 256 < Short.MAX_VALUE + 1) {
-				codeLen = byteBuffer.getShort() & 0xffff;
-			} else if (numCodePages * 256 <= Integer.MAX_VALUE) {
-				codeLen = byteBuffer.getInt();
-			}
-
-			// Extract code bytes
-			byte[] codeBytes = new byte[codeLen];
-			byteBuffer.get(codeBytes);
-
-			// Create AT
-			boolean isSleeping = false;
-			Integer sleepUntilHeight = null;
-			boolean isFinished = false;
-			boolean hadFatalError = false;
-			boolean isFrozen = false;
-			Long frozenBalance = null;
-
-			this.atData = new ATData(atAddress, creatorPublicKey, creation, version, Asset.QORT, codeBytes, isSleeping, sleepUntilHeight, isFinished,
-					hadFatalError, isFrozen, frozenBalance);
-
-			this.atStateData = new ATStateData(atAddress, height, creation, null, null, BigDecimal.ZERO.setScale(8));
-		}
+		this.atStateData = new ATStateData(atAddress, height, creation, stateData, stateHash, 0L, true);
 	}
 
 	// Getters / setters
@@ -116,9 +75,7 @@ public class AT {
 		ATRepository atRepository = this.repository.getATRepository();
 		atRepository.save(this.atData);
 
-		// For version 2+ we also store initial AT state data
-		if (this.atData.getVersion() >= 2)
-			atRepository.save(this.atStateData);
+		atRepository.save(this.atStateData);
 	}
 
 	public void undeploy() throws DataException {
@@ -126,34 +83,89 @@ public class AT {
 		this.repository.getATRepository().delete(this.atData.getATAddress());
 	}
 
-	public List<AtTransaction> run(long blockTimestamp) throws DataException {
+	public List<AtTransaction> run(int blockHeight, long blockTimestamp) throws DataException {
 		String atAddress = this.atData.getATAddress();
 
 		QortalATAPI api = new QortalATAPI(repository, this.atData, blockTimestamp);
-		QortalATLogger logger = new QortalATLogger();
+		QortalAtLoggerFactory loggerFactory = QortalAtLoggerFactory.getInstance();
 
 		byte[] codeBytes = this.atData.getCodeBytes();
 
-		// Fetch latest ATStateData for this AT (if any)
+		// Fetch latest ATStateData for this AT
 		ATStateData latestAtStateData = this.repository.getATRepository().getLatestATState(atAddress);
 
-		// There should be at least initial AT state data
+		// There should be at least initial deployment AT state data
 		if (latestAtStateData == null)
-			throw new IllegalStateException("No initial AT state data found");
+			throw new IllegalStateException("No previous AT state data found");
 
 		// [Re]create AT machine state using AT state data or from scratch as applicable
-		MachineState state = MachineState.fromBytes(api, logger, latestAtStateData.getStateData(), codeBytes);
-		state.execute();
+		MachineState state = MachineState.fromBytes(api, loggerFactory, latestAtStateData.getStateData(), codeBytes);
+		try {
+			state.execute();
+		} catch (Exception e) {
+			throw new DataException(String.format("Uncaught exception while running AT '%s'", atAddress), e);
+		}
 
-		int height = this.repository.getBlockRepository().getBlockchainHeight() + 1;
 		long creation = this.atData.getCreation();
 		byte[] stateData = state.toBytes();
 		byte[] stateHash = Crypto.digest(stateData);
-		BigDecimal atFees = api.calcFinalFees(state);
+		long atFees = api.calcFinalFees(state);
 
-		this.atStateData = new ATStateData(atAddress, height, creation, stateData, stateHash, atFees);
+		this.atStateData = new ATStateData(atAddress, blockHeight, creation, stateData, stateHash, atFees, false);
 
 		return api.getTransactions();
 	}
 
+	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);
+
+		// Save latest AT state data
+		this.repository.getATRepository().save(this.atStateData);
+
+		// Update AT info in repository too
+		this.atData.setIsSleeping(state.isSleeping());
+		this.atData.setSleepUntilHeight(state.getSleepUntilHeight());
+		this.atData.setIsFinished(state.isFinished());
+		this.atData.setHadFatalError(state.hadFatalError());
+		this.atData.setIsFrozen(state.isFrozen());
+		this.atData.setFrozenBalance(state.getFrozenBalance());
+		this.repository.getATRepository().save(this.atData);
+	}
+
+	public void revert(int blockHeight, long blockTimestamp) throws DataException {
+		String atAddress = this.atData.getATAddress();
+
+		// Delete old AT state data from repository
+		this.repository.getATRepository().delete(atAddress, blockHeight);
+
+		if (this.atStateData.isInitial())
+			return;
+
+		// Load previous state data
+		ATStateData previousStateData = this.repository.getATRepository().getLatestATState(atAddress);
+		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);
+
+		// Update AT info in repository
+		this.atData.setIsSleeping(state.isSleeping());
+		this.atData.setSleepUntilHeight(state.getSleepUntilHeight());
+		this.atData.setIsFinished(state.isFinished());
+		this.atData.setHadFatalError(state.hadFatalError());
+		this.atData.setIsFrozen(state.isFrozen());
+		this.atData.setFrozenBalance(state.getFrozenBalance());
+		this.repository.getATRepository().save(this.atData);
+	}
+
 }

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

@@ -1,134 +0,0 @@
-package org.qortal.at;
-
-import static java.util.Arrays.stream;
-import static java.util.stream.Collectors.toMap;
-
-import java.math.BigDecimal;
-import java.util.List;
-import java.util.Map;
-
-import org.ciyam.at.MachineState;
-import org.ciyam.at.Timestamp;
-import org.qortal.account.Account;
-import org.qortal.block.Block;
-import org.qortal.data.block.BlockData;
-import org.qortal.data.transaction.ATTransactionData;
-import org.qortal.data.transaction.PaymentTransactionData;
-import org.qortal.data.transaction.TransactionData;
-import org.qortal.repository.BlockRepository;
-import org.qortal.repository.DataException;
-import org.qortal.transaction.Transaction;
-
-public enum BlockchainAPI {
-
-	QORTAL(0) {
-		@Override
-		public void putTransactionFromRecipientAfterTimestampInA(String recipient, Timestamp timestamp, MachineState state) {
-			int height = timestamp.blockHeight;
-			int sequence = timestamp.transactionSequence + 1;
-
-			QortalATAPI api = (QortalATAPI) state.getAPI();
-			BlockRepository blockRepository = api.repository.getBlockRepository();
-
-			try {
-				Account recipientAccount = new Account(api.repository, recipient);
-
-				while (height <= blockRepository.getBlockchainHeight()) {
-					BlockData blockData = blockRepository.fromHeight(height);
-
-					if (blockData == null)
-						throw new DataException("Unable to fetch block " + height + " from repository?");
-
-					Block block = new Block(api.repository, blockData);
-
-					List<Transaction> transactions = block.getTransactions();
-
-					// No more transactions in this block? Try next block
-					if (sequence >= transactions.size()) {
-						++height;
-						sequence = 0;
-						continue;
-					}
-
-					Transaction transaction = transactions.get(sequence);
-
-					// Transaction needs to be sent to specified recipient
-					if (transaction.getRecipientAccounts().contains(recipientAccount)) {
-						// Found a transaction
-
-						api.setA1(state, new Timestamp(height, timestamp.blockchainId, sequence).longValue());
-
-						// Hash transaction's signature into other three A fields for future verification that it's the same transaction
-						byte[] hash = QortalATAPI.sha192(transaction.getTransactionData().getSignature());
-
-						api.setA2(state, QortalATAPI.fromBytes(hash, 0));
-						api.setA3(state, QortalATAPI.fromBytes(hash, 8));
-						api.setA4(state, QortalATAPI.fromBytes(hash, 16));
-						return;
-					}
-
-					// Transaction wasn't for us - keep going
-					++sequence;
-				}
-
-				// No more transactions - zero A and exit
-				api.zeroA(state);
-			} catch (DataException e) {
-				throw new RuntimeException("AT API unable to fetch next transaction?", e);
-			}
-		}
-
-		@Override
-		public long getAmountFromTransactionInA(Timestamp timestamp, MachineState state) {
-			QortalATAPI api = (QortalATAPI) state.getAPI();
-			TransactionData transactionData = api.fetchTransaction(state);
-
-			switch (transactionData.getType()) {
-				case PAYMENT:
-					return ((PaymentTransactionData) transactionData).getAmount().unscaledValue().longValue();
-
-				case AT:
-					BigDecimal amount = ((ATTransactionData) transactionData).getAmount();
-
-					if (amount != null)
-						return amount.unscaledValue().longValue();
-					else
-						return 0xffffffffffffffffL;
-
-				default:
-					return 0xffffffffffffffffL;
-			}
-		}
-	},
-	BTC(1) {
-		@Override
-		public void putTransactionFromRecipientAfterTimestampInA(String recipient, Timestamp timestamp, MachineState state) {
-			// TODO BTC transaction support for ATv2
-		}
-
-		@Override
-		public long getAmountFromTransactionInA(Timestamp timestamp, MachineState state) {
-			// TODO BTC transaction support for ATv2
-			return 0;
-		}
-	};
-
-	public final int value;
-
-	private static final Map<Integer, BlockchainAPI> map = stream(BlockchainAPI.values()).collect(toMap(type -> type.value, type -> type));
-
-	BlockchainAPI(int value) {
-		this.value = value;
-	}
-
-	public static BlockchainAPI valueOf(int value) {
-		return map.get(value);
-	}
-
-	// Blockchain-specific API methods
-
-	public abstract void putTransactionFromRecipientAfterTimestampInA(String recipient, Timestamp timestamp, MachineState state);
-
-	public abstract long getAmountFromTransactionInA(Timestamp timestamp, MachineState state);
-
-}

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

@@ -1,11 +1,11 @@
 package org.qortal.at;
 
-import java.math.BigDecimal;
-import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.ciyam.at.API;
 import org.ciyam.at.ExecutionException;
 import org.ciyam.at.FunctionData;
@@ -14,35 +14,42 @@ import org.ciyam.at.MachineState;
 import org.ciyam.at.OpCode;
 import org.ciyam.at.Timestamp;
 import org.qortal.account.Account;
-import org.qortal.account.GenesisAccount;
+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;
 import org.qortal.data.at.ATData;
 import org.qortal.data.block.BlockData;
+import org.qortal.data.block.BlockSummaryData;
 import org.qortal.data.transaction.ATTransactionData;
 import org.qortal.data.transaction.BaseTransactionData;
 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.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 com.google.common.primitives.Bytes;
 
 public class QortalATAPI extends API {
 
-	// Useful constants
-	private static final BigDecimal FEE_PER_STEP = BigDecimal.valueOf(1.0).setScale(8); // 1 QORT per "step"
-	private static final int MAX_STEPS_PER_ROUND = 500;
-	private static final int STEPS_PER_FUNCTION_CALL = 10;
-	private static final int MINUTES_PER_BLOCK = 10;
+	private static final byte[] ADDRESS_PADDING = new byte[32 - Account.ADDRESS_LENGTH];
+	private static final Logger LOGGER = LogManager.getLogger(QortalATAPI.class);
 
 	// Properties
-	Repository repository;
-	ATData atData;
-	long blockTimestamp;
+	private Repository repository;
+	private ATData atData;
+	private long blockTimestamp;
+	private final CiyamAtSettings ciyamAtSettings;
 
 	/** List of generated AT transactions */
 	List<AtTransaction> transactions;
@@ -54,36 +61,42 @@ public class QortalATAPI extends API {
 		this.atData = atData;
 		this.transactions = new ArrayList<>();
 		this.blockTimestamp = blockTimestamp;
+
+		this.ciyamAtSettings = BlockChain.getInstance().getCiyamAtSettings();
 	}
 
 	// Methods specific to Qortal AT processing, not inherited
 
+	public Repository getRepository() {
+		return this.repository;
+	}
+
 	public List<AtTransaction> getTransactions() {
 		return this.transactions;
 	}
 
-	public BigDecimal calcFinalFees(MachineState state) {
-		return FEE_PER_STEP.multiply(BigDecimal.valueOf(state.getSteps()));
+	public long calcFinalFees(MachineState state) {
+		return state.getSteps() * this.ciyamAtSettings.feePerStep;
 	}
 
 	// Inherited methods from CIYAM AT API
 
 	@Override
 	public int getMaxStepsPerRound() {
-		return MAX_STEPS_PER_ROUND;
+		return this.ciyamAtSettings.maxStepsPerRound;
 	}
 
 	@Override
 	public int getOpCodeSteps(OpCode opcode) {
 		if (opcode.value >= OpCode.EXT_FUN.value && opcode.value <= OpCode.EXT_FUN_RET_DAT_2.value)
-			return STEPS_PER_FUNCTION_CALL;
+			return this.ciyamAtSettings.stepsPerFunctionCall;
 
 		return 1;
 	}
 
 	@Override
 	public long getFeePerStep() {
-		return FEE_PER_STEP.unscaledValue().longValue();
+		return this.ciyamAtSettings.feePerStep;
 	}
 
 	@Override
@@ -105,31 +118,95 @@ public class QortalATAPI extends API {
 	}
 
 	@Override
-	public void putPreviousBlockHashInA(MachineState state) {
+	public void putPreviousBlockHashIntoA(MachineState state) {
 		try {
-			BlockData blockData = this.repository.getBlockRepository().fromHeight(this.getPreviousBlockHeight());
+			int previousBlockHeight = this.repository.getBlockRepository().getBlockchainHeight() - 1;
+
+			// We only need signature, so only request a block summary
+			List<BlockSummaryData> blockSummaries = this.repository.getBlockRepository().getBlockSummaries(previousBlockHeight, previousBlockHeight);
+			if (blockSummaries == null || blockSummaries.size() != 1)
+				throw new RuntimeException("AT API unable to fetch previous block hash?");
 
 			// Block's signature is 128 bytes so we need to reduce this to 4 longs (32 bytes)
-			byte[] blockHash = Crypto.digest(blockData.getSignature());
+			// To be able to use hash to look up block, save height (8 bytes) and partial signature (24 bytes)
+			this.setA1(state, previousBlockHeight);
 
-			this.setA(state, blockHash);
+			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));
 		} catch (DataException e) {
 			throw new RuntimeException("AT API unable to fetch previous block?", e);
 		}
 	}
 
 	@Override
-	public void putTransactionAfterTimestampInA(Timestamp timestamp, MachineState state) {
+	public void putTransactionAfterTimestampIntoA(Timestamp timestamp, MachineState state) {
 		// Recipient is this AT
-		String recipient = this.atData.getATAddress();
+		String atAddress = this.atData.getATAddress();
 
-		BlockchainAPI blockchainAPI = BlockchainAPI.valueOf(timestamp.blockchainId);
-		blockchainAPI.putTransactionFromRecipientAfterTimestampInA(recipient, timestamp, state);
+		int height = timestamp.blockHeight;
+		int sequence = timestamp.transactionSequence + 1;
+
+		BlockRepository blockRepository = this.getRepository().getBlockRepository();
+
+		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);
+		} catch (DataException e) {
+			throw new RuntimeException("AT API unable to fetch next transaction?", e);
+		}
 	}
 
 	@Override
 	public long getTypeFromTransactionInA(MachineState state) {
-		TransactionData transactionData = this.fetchTransaction(state);
+		TransactionData transactionData = this.getTransactionFromA(state);
 
 		switch (transactionData.getType()) {
 			case PAYMENT:
@@ -151,22 +228,36 @@ public class QortalATAPI extends API {
 
 	@Override
 	public long getAmountFromTransactionInA(MachineState state) {
-		Timestamp timestamp = new Timestamp(state.getA1());
-		BlockchainAPI blockchainAPI = BlockchainAPI.valueOf(timestamp.blockchainId);
-		return blockchainAPI.getAmountFromTransactionInA(timestamp, state);
+		TransactionData transactionData = this.getTransactionFromA(state);
+
+		switch (transactionData.getType()) {
+			case PAYMENT:
+				return ((PaymentTransactionData) transactionData).getAmount();
+
+			case AT:
+				Long amount = ((ATTransactionData) transactionData).getAmount();
+
+				if (amount != null)
+					return amount;
+
+				// fall-through to default
+
+			default:
+				return 0xffffffffffffffffL;
+		}
 	}
 
 	@Override
 	public long getTimestampFromTransactionInA(MachineState state) {
 		// Transaction's "timestamp" already stored in A1
-		Timestamp timestamp = new Timestamp(state.getA1());
+		Timestamp timestamp = new Timestamp(this.getA1(state));
 		return timestamp.longValue();
 	}
 
 	@Override
 	public long generateRandomUsingTransactionInA(MachineState state) {
-		// The plan here is to sleep for a block then use next block's signature and this transaction's signature to generate pseudo-random, but deterministic,
-		// value.
+		// The plan here is to sleep for a block then use next block's signature
+		// and this transaction's signature to generate pseudo-random, but deterministic, value.
 
 		if (!isFirstOpCodeAfterSleeping(state)) {
 			// First call
@@ -179,7 +270,7 @@ public class QortalATAPI extends API {
 			// Second call
 
 			// HASH(A and new block hash)
-			TransactionData transactionData = this.fetchTransaction(state);
+			TransactionData transactionData = this.getTransactionFromA(state);
 
 			try {
 				BlockData blockData = this.repository.getBlockRepository().getLastBlock();
@@ -203,7 +294,7 @@ public class QortalATAPI extends API {
 		// Zero B in case of issues or shorter-than-B message
 		this.zeroB(state);
 
-		TransactionData transactionData = this.fetchTransaction(state);
+		TransactionData transactionData = this.getTransactionFromA(state);
 
 		byte[] messageData = null;
 
@@ -233,20 +324,36 @@ public class QortalATAPI extends API {
 
 	@Override
 	public void putAddressFromTransactionInAIntoB(MachineState state) {
-		TransactionData transactionData = this.fetchTransaction(state);
+		TransactionData transactionData = this.getTransactionFromA(state);
 
-		// We actually use public key as it has more potential utility (e.g. message verification) than an address
-		byte[] bytes = transactionData.getCreatorPublicKey();
+		String address;
+		if (transactionData.getType() == TransactionType.AT) {
+			// Use AT address from transaction data, as transaction's public key will always be fake
+			address = ((ATTransactionData) transactionData).getATAddress();
+		} else {
+			byte[] publicKey = transactionData.getCreatorPublicKey();
+			address = Crypto.toAddress(publicKey);
+		}
 
-		this.setB(state, bytes);
+		// Convert to byte form as this only takes 25 bytes,
+		// compared to string-form's 34 bytes,
+		// and we only have 32 bytes available.
+		byte[] addressBytes = Bytes.ensureCapacity(Base58.decode(address), 32, 0); // pad to 32 bytes
+
+		this.setB(state, addressBytes);
 	}
 
 	@Override
 	public void putCreatorAddressIntoB(MachineState state) {
-		// We actually use public key as it has more potential utility (e.g. message verification) than an address
-		byte[] bytes = atData.getCreatorPublicKey();
+		byte[] publicKey = atData.getCreatorPublicKey();
+		String address = Crypto.toAddress(publicKey);
 
-		this.setB(state, bytes);
+		// Convert to byte form as this only takes 25 bytes,
+		// compared to string-form's 34 bytes,
+		// and we only have 32 bytes available.
+		byte[] addressBytes = Bytes.ensureCapacity(Base58.decode(address), 32, 0); // pad to 32 bytes
+
+		this.setB(state, addressBytes);
 	}
 
 	@Override
@@ -254,25 +361,22 @@ public class QortalATAPI extends API {
 		try {
 			Account atAccount = this.getATAccount();
 
-			return atAccount.getConfirmedBalance(Asset.QORT).unscaledValue().longValue();
+			return atAccount.getConfirmedBalance(Asset.QORT);
 		} catch (DataException e) {
 			throw new RuntimeException("AT API unable to fetch AT's current balance?", e);
 		}
 	}
 
 	@Override
-	public void payAmountToB(long unscaledAmount, MachineState state) {
-		byte[] publicKey = state.getB();
-
-		PublicKeyAccount recipient = new PublicKeyAccount(this.repository, publicKey);
+	public void payAmountToB(long amount, MachineState state) {
+		Account recipient = getAccountFromB(state);
 
 		long timestamp = this.getNextTransactionTimestamp();
 		byte[] reference = this.getLastReference();
-		BigDecimal amount = BigDecimal.valueOf(unscaledAmount, 8);
 
-		BaseTransactionData baseTransactionData = new BaseTransactionData(timestamp, Group.NO_GROUP, reference, GenesisAccount.PUBLIC_KEY, BigDecimal.ZERO, null);
+		BaseTransactionData baseTransactionData = new BaseTransactionData(timestamp, Group.NO_GROUP, reference, NullAccount.PUBLIC_KEY, 0L, null);
 		ATTransactionData atTransactionData = new ATTransactionData(baseTransactionData, this.atData.getATAddress(),
-				recipient.getAddress(), amount, this.atData.getAssetId(), new byte[0]);
+				recipient.getAddress(), amount, this.atData.getAssetId());
 		AtTransaction atTransaction = new AtTransaction(this.repository, atTransactionData);
 
 		// Add to our transactions
@@ -281,17 +385,15 @@ public class QortalATAPI extends API {
 
 	@Override
 	public void messageAToB(MachineState state) {
-		byte[] message = state.getA();
-		byte[] publicKey = state.getB();
-
-		PublicKeyAccount recipient = new PublicKeyAccount(this.repository, publicKey);
+		byte[] message = this.getA(state);
+		Account recipient = getAccountFromB(state);
 
 		long timestamp = this.getNextTransactionTimestamp();
 		byte[] reference = this.getLastReference();
 
-		BaseTransactionData baseTransactionData = new BaseTransactionData(timestamp, Group.NO_GROUP, reference, GenesisAccount.PUBLIC_KEY, BigDecimal.ZERO, null);
+		BaseTransactionData baseTransactionData = new BaseTransactionData(timestamp, Group.NO_GROUP, reference, NullAccount.PUBLIC_KEY, 0L, null);
 		ATTransactionData atTransactionData = new ATTransactionData(baseTransactionData, this.atData.getATAddress(),
-				recipient.getAddress(), BigDecimal.ZERO, this.atData.getAssetId(), message);
+				recipient.getAddress(), message);
 		AtTransaction atTransaction = new AtTransaction(this.repository, atTransactionData);
 
 		// Add to our transactions
@@ -303,22 +405,24 @@ public class QortalATAPI extends API {
 		int blockHeight = timestamp.blockHeight;
 
 		// At least one block in the future
-		blockHeight += (minutes / MINUTES_PER_BLOCK) + 1;
+		blockHeight += Math.max(minutes / this.ciyamAtSettings.minutesPerBlock, 1);
 
 		return new Timestamp(blockHeight, 0).longValue();
 	}
 
 	@Override
 	public void onFinished(long finalBalance, MachineState state) {
+		if (finalBalance <= 0)
+			return;
+
 		// Refund remaining balance (if any) to AT's creator
 		Account creator = this.getCreator();
 		long timestamp = this.getNextTransactionTimestamp();
 		byte[] reference = this.getLastReference();
-		BigDecimal amount = BigDecimal.valueOf(finalBalance, 8);
 
-		BaseTransactionData baseTransactionData = new BaseTransactionData(timestamp, Group.NO_GROUP, reference, GenesisAccount.PUBLIC_KEY, BigDecimal.ZERO, null);
+		BaseTransactionData baseTransactionData = new BaseTransactionData(timestamp, Group.NO_GROUP, reference, NullAccount.PUBLIC_KEY, 0L, null);
 		ATTransactionData atTransactionData = new ATTransactionData(baseTransactionData, this.atData.getATAddress(),
-				creator.getAddress(), amount, this.atData.getAssetId(), new byte[0]);
+				creator.getAddress(), finalBalance, this.atData.getAssetId());
 		AtTransaction atTransaction = new AtTransaction(this.repository, atTransactionData);
 
 		// Add to our transactions
@@ -327,7 +431,7 @@ public class QortalATAPI extends API {
 
 	@Override
 	public void onFatalError(MachineState state, ExecutionException e) {
-		state.getLogger().error("AT " + this.atData.getATAddress() + " suffered fatal error: " + e.getMessage());
+		LOGGER.error("AT " + this.atData.getATAddress() + " suffered fatal error: " + e.getMessage());
 	}
 
 	@Override
@@ -338,13 +442,16 @@ public class QortalATAPI extends API {
 		if (qortalFunctionCode == null)
 			throw new IllegalFunctionCodeException("Unknown Qortal function code 0x" + String.format("%04x", rawFunctionCode) + " encountered");
 
-		qortalFunctionCode.preExecuteCheck(2, true, state, rawFunctionCode);
+		qortalFunctionCode.preExecuteCheck(paramCount, returnValueExpected, rawFunctionCode);
 	}
 
 	@Override
 	public void platformSpecificPostCheckExecute(FunctionData functionData, MachineState state, short rawFunctionCode) throws ExecutionException {
 		QortalFunctionCode qortalFunctionCode = QortalFunctionCode.valueOf(rawFunctionCode);
 
+		if (qortalFunctionCode == null)
+			throw new IllegalFunctionCodeException("Unknown Qortal function code 0x" + String.format("%04x", rawFunctionCode) + " encountered");
+
 		qortalFunctionCode.execute(functionData, state, rawFunctionCode);
 	}
 
@@ -356,29 +463,23 @@ public class QortalATAPI extends API {
 				| (bytes[start + 4] & 0xffL) << 32 | (bytes[start + 5] & 0xffL) << 40 | (bytes[start + 6] & 0xffL) << 48 | (bytes[start + 7] & 0xffL) << 56;
 	}
 
-	/** Returns SHA2-192 digest of input - used to verify transaction signatures */
-	public static byte[] sha192(byte[] input) {
-		try {
-			// SHA2-192
-			MessageDigest sha192 = MessageDigest.getInstance("SHA-192");
-			return sha192.digest(input);
-		} catch (NoSuchAlgorithmException e) {
-			throw new RuntimeException("SHA-192 not available");
-		}
+	/** 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);
 	}
 
-	/** Verify transaction's SHA2-192 hashed signature matches A2 thru A4 */
-	private static void verifyTransaction(TransactionData transactionData, MachineState state) {
-		// Compare SHA2-192 of transaction's signature against A2 thru A4
-		byte[] hash = sha192(transactionData.getSignature());
+	/** Verify transaction's partial signature matches A2 thru A4 */
+	private void verifyTransaction(TransactionData transactionData, MachineState state) {
+		// Compare end of transaction's signature against A2 thru A4
+		byte[] sig = transactionData.getSignature();
 
-		if (state.getA2() != fromBytes(hash, 0) || state.getA3() != fromBytes(hash, 8) || state.getA4() != fromBytes(hash, 16))
+		if (this.getA2(state) != fromBytes(sig, 8) || this.getA3(state) != fromBytes(sig, 16) || this.getA4(state) != fromBytes(sig, 24))
 			throw new IllegalStateException("Transaction signature in A no longer matches signature from repository");
 	}
 
 	/** Returns transaction data from repository using block height & sequence from A1, checking the transaction signatures match too */
-	/* package */ TransactionData fetchTransaction(MachineState state) {
-		Timestamp timestamp = new Timestamp(state.getA1());
+	/* package */ TransactionData getTransactionFromA(MachineState state) {
+		Timestamp timestamp = new Timestamp(this.getA1(state));
 
 		try {
 			TransactionData transactionData = this.repository.getTransactionRepository().fromHeightAndSequence(timestamp.blockHeight,
@@ -409,29 +510,17 @@ public class QortalATAPI extends API {
 	/** Returns the timestamp to use for next AT Transaction */
 	private long getNextTransactionTimestamp() {
 		/*
-		 * Timestamp is block's timestamp + position in AT-Transactions list.
+		 * Use block's timestamp.
 		 * 
-		 * We need increasing timestamps to preserve transaction order and hence a correct signature-reference chain when the block is processed.
-		 * 
-		 * As Qora blocks must share the same milliseconds component in their timestamps, this allows us to generate up to 1,000 AT-Transactions per AT without
-		 * issue.
-		 * 
-		 * As long as ATs are not allowed to generate that many per block, e.g. by limiting maximum steps per execution round, then we should be fine.
+		 * This is OK because AT transactions are always generated locally and order is preserved in Transaction.getDataComparator().
 		 */
-
-		// XXX THE ABOVE IS NO LONGER TRUE IN QORTAL!
-		// return this.blockTimestamp + this.transactions.size();
-		throw new RuntimeException("AT timestamp code not fixed!");
+		return this.blockTimestamp;
 	}
 
-	/** Returns AT account's lastReference, taking newly generated ATTransactions into account */
+	/** Returns AT account's lastReference */
 	private byte[] getLastReference() {
-		// Use signature from last AT Transaction we generated
-		if (!this.transactions.isEmpty())
-			return this.transactions.get(this.transactions.size() - 1).getTransactionData().getSignature();
-
 		try {
-			// No transactions yet, so look up AT's account's last reference from repository
+			// Look up AT's account's last reference from repository
 			Account atAccount = this.getATAccount();
 
 			return atAccount.getLastReference();
@@ -440,4 +529,38 @@ public class QortalATAPI extends API {
 		}
 	}
 
+	/**
+	 * Returns Account (possibly PublicKeyAccount) based on value in B.
+	 * <p>
+	 * If first byte in B starts with either address version bytes,<br>
+	 * and bytes 26 to 32 are zero, then use as an address, but only if valid.
+	 * <p>
+	 * Otherwise, assume B is a public key.
+	 */
+	private Account getAccountFromB(MachineState state) {
+		byte[] bBytes = this.getB(state);
+
+		if ((bBytes[0] == Crypto.ADDRESS_VERSION || bBytes[0] == Crypto.AT_ADDRESS_VERSION)
+				&& Arrays.mismatch(bBytes, Account.ADDRESS_LENGTH, 32, ADDRESS_PADDING, 0, ADDRESS_PADDING.length) == -1) {
+			// Extract only the bytes containing address
+			byte[] addressBytes = Arrays.copyOf(bBytes, Account.ADDRESS_LENGTH);
+			// If address (in byte form) is valid...
+			if (Crypto.isValidAddress(addressBytes))
+				// ...then return an Account using address (converted to Base58
+				return new Account(this.repository, Base58.encode(addressBytes));
+		}
+
+		return new PublicKeyAccount(this.repository, bBytes);
+	}
+
+	/* Convenience methods to allow QortalFunctionCode package-visibility access to A/B-get/set methods. */
+
+	protected byte[] getB(MachineState state) {
+		return super.getB(state);
+	}
+
+	protected void setB(MachineState state, byte[] bBytes) {
+		super.setB(state, bBytes);
+	}
+
 }

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

@@ -1,26 +0,0 @@
-package org.qortal.at;
-
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
-
-public class QortalATLogger implements org.ciyam.at.LoggerInterface {
-
-	// NOTE: We're logging on behalf of org.qortal.at.AT, not ourselves!
-	private static final Logger LOGGER = LogManager.getLogger(AT.class);
-
-	@Override
-	public void error(String message) {
-		LOGGER.error(message);
-	}
-
-	@Override
-	public void debug(String message) {
-		LOGGER.debug(message);
-	}
-
-	@Override
-	public void echo(String message) {
-		LOGGER.info(message);
-	}
-
-}

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

@@ -0,0 +1,24 @@
+package org.qortal.at;
+
+import org.ciyam.at.AtLogger;
+
+public class QortalAtLoggerFactory implements org.ciyam.at.AtLoggerFactory {
+
+	private static QortalAtLoggerFactory instance;
+
+	private QortalAtLoggerFactory() {
+	}
+
+	public static synchronized QortalAtLoggerFactory getInstance() {
+		if (instance == null)
+			instance = new QortalAtLoggerFactory();
+
+		return instance;
+	}
+
+	@Override
+	public AtLogger create(final Class<?> loggerName) {
+		return QortalAtLogger.create(loggerName);
+	}
+
+}

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

@@ -1,15 +1,18 @@
 package org.qortal.at;
 
-import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.Map;
 import java.util.stream.Collectors;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.ciyam.at.ExecutionException;
 import org.ciyam.at.FunctionData;
 import org.ciyam.at.IllegalFunctionCodeException;
 import org.ciyam.at.MachineState;
-import org.ciyam.at.Timestamp;
+import org.qortal.crosschain.BTC;
+import org.qortal.crypto.Crypto;
+import org.qortal.settings.Settings;
 
 /**
  * Qortal-specific CIYAM-AT Functions.
@@ -19,28 +22,43 @@ import org.ciyam.at.Timestamp;
  */
 public enum QortalFunctionCode {
 	/**
-	 * <tt>0x0500</tt><br>
-	 * Returns current BTC block's "timestamp"
+	 * <tt>0x0510</tt><br>
+	 * Convert address in B to 20-byte value in LSB of B1, and all of B2 & B3.
 	 */
-	GET_BTC_BLOCK_TIMESTAMP(0x0500, 0, true) {
+	CONVERT_B_TO_PKH(0x0510, 0, false) {
 		@Override
 		protected void postCheckExecute(FunctionData functionData, MachineState state, short rawFunctionCode) throws ExecutionException {
-			functionData.returnValue = Timestamp.toLong(state.getAPI().getCurrentBlockHeight(), BlockchainAPI.BTC.value, 0);
+			// Needs to be 'B' sized
+			byte[] pkh = new byte[32];
+
+			// Copy PKH part of B to last 20 bytes
+			System.arraycopy(getB(state), 32 - 20 - 4, pkh, 32 - 20, 20);
+
+			setB(state, pkh);
 		}
 	},
 	/**
-	 * <tt>0x0501</tt><br>
-	 * Put transaction from specific recipient after timestamp in A, or zero if none<br>
+	 * <tt>0x0511</tt><br>
+	 * Convert 20-byte value in LSB of B1, and all of B2 & B3 to P2SH.<br>
+	 * P2SH stored in lower 25 bytes of B.
 	 */
-	PUT_TX_FROM_B_RECIPIENT_AFTER_TIMESTAMP_IN_A(0x0501, 1, false) {
+	CONVERT_B_TO_P2SH(0x0511, 0, false) {
 		@Override
 		protected void postCheckExecute(FunctionData functionData, MachineState state, short rawFunctionCode) throws ExecutionException {
-			Timestamp timestamp = new Timestamp(functionData.value2);
+			byte addressPrefix = Settings.getInstance().getBitcoinNet() == BTC.BitcoinNet.MAIN ? 0x05 : (byte) 0xc4;
 
-			String recipient = new String(state.getB(), StandardCharsets.UTF_8);
-
-			BlockchainAPI blockchainAPI = BlockchainAPI.valueOf(timestamp.blockchainId);
-			blockchainAPI.putTransactionFromRecipientAfterTimestampInA(recipient, timestamp, state);
+			convertAddressInB(addressPrefix, state);
+		}
+	},
+	/**
+	 * <tt>0x0512</tt><br>
+	 * Convert 20-byte value in LSB of B1, and all of B2 & B3 to Qortal address.<br>
+	 * Qortal address stored in lower 25 bytes of B.
+	 */
+	CONVERT_B_TO_QORTAL(0x0512, 0, false) {
+		@Override
+		protected void postCheckExecute(FunctionData functionData, MachineState state, short rawFunctionCode) throws ExecutionException {
+			convertAddressInB(Crypto.ADDRESS_VERSION, state);
 		}
 	};
 
@@ -48,7 +66,9 @@ public enum QortalFunctionCode {
 	public final int paramCount;
 	public final boolean returnsValue;
 
-	private final static Map<Short, QortalFunctionCode> map = Arrays.stream(QortalFunctionCode.values())
+	private static final Logger LOGGER = LogManager.getLogger(QortalFunctionCode.class);
+
+	private static final Map<Short, QortalFunctionCode> map = Arrays.stream(QortalFunctionCode.values())
 			.collect(Collectors.toMap(functionCode -> functionCode.value, functionCode -> functionCode));
 
 	private QortalFunctionCode(int value, int paramCount, boolean returnsValue) {
@@ -61,7 +81,7 @@ public enum QortalFunctionCode {
 		return map.get((short) value);
 	}
 
-	public void preExecuteCheck(int paramCount, boolean returnValueExpected, MachineState state, short rawFunctionCode) throws IllegalFunctionCodeException {
+	public void preExecuteCheck(int paramCount, boolean returnValueExpected, short rawFunctionCode) throws IllegalFunctionCodeException {
 		if (paramCount != this.paramCount)
 			throw new IllegalFunctionCodeException(
 					"Passed paramCount (" + paramCount + ") does not match function's required paramCount (" + this.paramCount + ")");
@@ -84,7 +104,7 @@ public enum QortalFunctionCode {
 	 */
 	public void execute(FunctionData functionData, MachineState state, short rawFunctionCode) throws ExecutionException {
 		// Check passed functionData against requirements of this function
-		preExecuteCheck(functionData.paramCount, functionData.returnValueExpected, state, rawFunctionCode);
+		preExecuteCheck(functionData.paramCount, functionData.returnValueExpected, rawFunctionCode);
 
 		if (functionData.paramCount >= 1 && functionData.value1 == null)
 			throw new IllegalFunctionCodeException("Passed value1 is null but function has paramCount of (" + this.paramCount + ")");
@@ -92,7 +112,7 @@ public enum QortalFunctionCode {
 		if (functionData.paramCount == 2 && functionData.value2 == null)
 			throw new IllegalFunctionCodeException("Passed value2 is null but function has paramCount of (" + this.paramCount + ")");
 
-		state.getLogger().debug("Function \"" + this.name() + "\"");
+		LOGGER.debug(() -> String.format("Function \"%s\"", this.name()));
 
 		postCheckExecute(functionData, state, rawFunctionCode);
 	}
@@ -100,4 +120,29 @@ public enum QortalFunctionCode {
 	/** Actually execute function */
 	protected abstract void postCheckExecute(FunctionData functionData, MachineState state, short rawFunctionCode) throws ExecutionException;
 
+	private static void convertAddressInB(byte addressPrefix, MachineState state) {
+		byte[] addressNoChecksum = new byte[1 + 20];
+		addressNoChecksum[0] = addressPrefix;
+		System.arraycopy(getB(state), 0, addressNoChecksum, 1, 20);
+
+		byte[] checksum = Crypto.doubleDigest(addressNoChecksum);
+
+		// Needs to be 'B' sized
+		byte[] address = new byte[32];
+		System.arraycopy(addressNoChecksum, 0, address, 32 - 1 - 20 - 4, addressNoChecksum.length);
+		System.arraycopy(checksum, 0, address, 32 - 4, 4);
+
+		setB(state, address);
+	}
+
+	private static byte[] getB(MachineState state) {
+		QortalATAPI api = (QortalATAPI) state.getAPI();
+		return api.getB(state);
+	}
+
+	private static void setB(MachineState state, byte[] bBytes) {
+		QortalATAPI api = (QortalATAPI) state.getAPI();
+		api.setB(state, bBytes);
+	}
+
 }

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

@@ -3,8 +3,6 @@ package org.qortal.block;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.InputStream;
-import java.math.BigDecimal;
-import java.math.MathContext;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -56,12 +54,14 @@ public class BlockChain {
 	/** Transaction expiry period, starting from transaction's timestamp, in milliseconds. */
 	private long transactionExpiryPeriod;
 
-	private BigDecimal unitFee;
-	private BigDecimal maxBytesPerUnitFee;
-	private BigDecimal minFeePerByte;
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long unitFee;
+
+	private int maxBytesPerUnitFee;
 
 	/** Maximum acceptable timestamp disagreement offset in milliseconds. */
 	private long blockTimestampMargin;
+
 	/** Maximum block size, in bytes. */
 	private int maxBlockSize;
 
@@ -71,15 +71,6 @@ public class BlockChain {
 	private GenesisBlock.GenesisInfo genesisInfo;
 
 	public enum FeatureTrigger {
-		messageHeight, // block height when MESSAGE transactions are enabled
-		atHeight, // block height when CIYAM automated transactions are enabled
-		assetsTimestamp, // timestamp when assets (issue/transfer/payments) are enabled
-		votingTimestamp, // timestamp when voting is enabled
-		arbitraryTimestamp, // timestamp when arbitrary transactions are enabled
-		powfixTimestamp, // timestamp when various legacy fixes come into effect
-		qortalTimestamp, // timestamp when Qortal changes come into effect
-		newAssetPricingTimestamp, // timestamp when new asset pricing comes into effect
-		groupApprovalTimestamp; // timestamp when transaction approval comes into effect
 	}
 
 	/** Map of which blockchain features are enabled when (height/timestamp) */
@@ -95,21 +86,28 @@ public class BlockChain {
 	/** Block rewards by block height */
 	public static class RewardByHeight {
 		public int height;
-		public BigDecimal reward;
+		@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+		public long reward;
 	}
-	List<RewardByHeight> rewardsByHeight;
+	private List<RewardByHeight> rewardsByHeight;
 
 	/** Share of block reward/fees by account level */
-	public static class ShareByLevel {
+	public static class AccountLevelShareBin {
 		public List<Integer> levels;
-		public BigDecimal share;
+		@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+		public long share;
 	}
-	List<ShareByLevel> sharesByLevel;
+	private List<AccountLevelShareBin> sharesByLevel;
+	/** Generated lookup of share-bin by account level */
+	private AccountLevelShareBin[] shareBinsByLevel;
 
 	/** Share of block reward/fees to legacy QORA coin holders */
-	BigDecimal qoraHoldersShare;
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private Long qoraHoldersShare;
+
 	/** How many legacy QORA per 1 QORT of block reward. */
-	BigDecimal qoraPerQortReward;
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private Long qoraPerQortReward;
 
 	/**
 	 * Number of minted blocks required to reach next level from previous.
@@ -120,7 +118,7 @@ public class BlockChain {
 	 * Example: if <tt>blocksNeededByLevel[3]</tt> is 200,<br>
 	 * then level 3 accounts need to mint 200 blocks to reach level 4.
 	 */
-	List<Integer> blocksNeededByLevel;
+	private List<Integer> blocksNeededByLevel;
 
 	/**
 	 * Cumulative number of minted blocks required to reach next level from scratch.
@@ -134,7 +132,7 @@ public class BlockChain {
 	 * <p>
 	 * Should NOT be present in blockchain config file!
 	 */
-	List<Integer> cumulativeBlocksByLevel;
+	private List<Integer> cumulativeBlocksByLevel;
 
 	/** Block times by block height */
 	public static class BlockTimingByHeight {
@@ -143,7 +141,7 @@ public class BlockChain {
 		public long deviation; // ms
 		public double power;
 	}
-	List<BlockTimingByHeight> blockTimingsByHeight;
+	private List<BlockTimingByHeight> blockTimingsByHeight;
 
 	private int minAccountLevelToMint = 1;
 	private int minAccountLevelToRewardShare;
@@ -155,6 +153,19 @@ public class BlockChain {
 	/** Maximum time to retain online account signatures (ms) for block validity checks, to allow for clock variance. */
 	private long onlineAccountSignaturesMaxLifetime;
 
+	/** Settings relating to CIYAM AT feature. */
+	public static class CiyamAtSettings {
+		/** Fee per step/op-code executed. */
+		@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+		public long feePerStep;
+		/** Maximum number of steps per execution round, before AT is forced to sleep until next block. */
+		public int maxStepsPerRound;
+		/** How many steps for calling a function. */
+		public int stepsPerFunctionCall;
+		/** Roughly how many minutes per block. */
+		public int minutesPerBlock;
+	}
+	private CiyamAtSettings ciyamAtSettings;
 
 	// Constructors, etc.
 
@@ -225,6 +236,19 @@ public class BlockChain {
 			Throwable linkedException = e.getLinkedException();
 			if (linkedException instanceof XMLMarshalException) {
 				String message = ((XMLMarshalException) linkedException).getInternalException().getLocalizedMessage();
+
+				if (message == null && linkedException.getCause() != null && linkedException.getCause().getCause() != null )
+					message = linkedException.getCause().getCause().getLocalizedMessage();
+
+				if (message == null && linkedException.getCause() != null)
+					message = linkedException.getCause().getLocalizedMessage();
+
+				if (message == null)
+					message = linkedException.getLocalizedMessage();
+
+				if (message == null)
+					message = e.getLocalizedMessage();
+
 				LOGGER.error(message);
 				throw new RuntimeException(message, e);
 			}
@@ -257,18 +281,14 @@ public class BlockChain {
 		return this.isTestChain;
 	}
 
-	public BigDecimal getUnitFee() {
+	public long getUnitFee() {
 		return this.unitFee;
 	}
 
-	public BigDecimal getMaxBytesPerUnitFee() {
+	public int getMaxBytesPerUnitFee() {
 		return this.maxBytesPerUnitFee;
 	}
 
-	public BigDecimal getMinFeePerByte() {
-		return this.minFeePerByte;
-	}
-
 	public long getTransactionExpiryPeriod() {
 		return this.transactionExpiryPeriod;
 	}
@@ -298,10 +318,14 @@ public class BlockChain {
 		return this.rewardsByHeight;
 	}
 
-	public List<ShareByLevel> getBlockSharesByLevel() {
+	public List<AccountLevelShareBin> getAccountLevelShareBins() {
 		return this.sharesByLevel;
 	}
 
+	public AccountLevelShareBin[] getShareBinsByAccountLevel() {
+		return this.shareBinsByLevel;
+	}
+
 	public List<Integer> getBlocksNeededByLevel() {
 		return this.blocksNeededByLevel;
 	}
@@ -310,11 +334,11 @@ public class BlockChain {
 		return this.cumulativeBlocksByLevel;
 	}
 
-	public BigDecimal getQoraHoldersShare() {
+	public long getQoraHoldersShare() {
 		return this.qoraHoldersShare;
 	}
 
-	public BigDecimal getQoraPerQortReward() {
+	public long getQoraPerQortReward() {
 		return this.qoraPerQortReward;
 	}
 
@@ -342,53 +366,21 @@ public class BlockChain {
 		return this.onlineAccountSignaturesMaxLifetime;
 	}
 
+	public CiyamAtSettings getCiyamAtSettings() {
+		return this.ciyamAtSettings;
+	}
+
 	// Convenience methods for specific blockchain feature triggers
 
-	public long getMessageReleaseHeight() {
-		return featureTriggers.get("messageHeight");
-	}
-
-	public long getATReleaseHeight() {
-		return featureTriggers.get("atHeight");
-	}
-
-	public long getPowFixReleaseTimestamp() {
-		return featureTriggers.get("powfixTimestamp");
-	}
-
-	public long getAssetsReleaseTimestamp() {
-		return featureTriggers.get("assetsTimestamp");
-	}
-
-	public long getVotingReleaseTimestamp() {
-		return featureTriggers.get("votingTimestamp");
-	}
-
-	public long getArbitraryReleaseTimestamp() {
-		return featureTriggers.get("arbitraryTimestamp");
-	}
-
-	public long getQortalTimestamp() {
-		return featureTriggers.get("qortalTimestamp");
-	}
-
-	public long getNewAssetPricingTimestamp() {
-		return featureTriggers.get("newAssetPricingTimestamp");
-	}
-
-	public long getGroupApprovalTimestamp() {
-		return featureTriggers.get("groupApprovalTimestamp");
-	}
-
 	// More complex getters for aspects that change by height or timestamp
 
-	public BigDecimal getRewardAtHeight(int ourHeight) {
+	public long getRewardAtHeight(int ourHeight) {
 		// Scan through for reward at our height
 		for (int i = rewardsByHeight.size() - 1; i >= 0; --i)
 			if (rewardsByHeight.get(i).height <= ourHeight)
 				return rewardsByHeight.get(i).reward;
 
-		return null;
+		return 0;
 	}
 
 	public BlockTimingByHeight getBlockTimingByHeight(int ourHeight) {
@@ -437,6 +429,9 @@ public class BlockChain {
 		if (this.founderEffectiveMintingLevel <= 0)
 			Settings.throwValidationError("Invalid/missing \"founderEffectiveMintingLevel\" in blockchain config");
 
+		if (this.ciyamAtSettings == null)
+			Settings.throwValidationError("No \"ciyamAtSettings\" entry found in blockchain config");
+
 		if (this.featureTriggers == null)
 			Settings.throwValidationError("No \"featureTriggers\" entry found in blockchain config");
 
@@ -444,15 +439,20 @@ public class BlockChain {
 		for (FeatureTrigger featureTrigger : FeatureTrigger.values())
 			if (!this.featureTriggers.containsKey(featureTrigger.name()))
 				Settings.throwValidationError(String.format("Missing feature trigger \"%s\" in blockchain config", featureTrigger.name()));
+
+		// Check block reward share bounds
+		long totalShare = this.qoraHoldersShare;
+		// Add share percents for account-level-based rewards
+		for (AccountLevelShareBin accountLevelShareBin : this.sharesByLevel)
+			totalShare += accountLevelShareBin.share;
+
+		if (totalShare < 0 || totalShare > 1_00000000L)
+			Settings.throwValidationError("Total non-founder share out of bounds (0<x<1e8)");
 	}
 
 	/** Minor normalization, cached value generation, etc. */
 	private void fixUp() {
-		this.maxBytesPerUnitFee = this.maxBytesPerUnitFee.setScale(8);
-		this.unitFee = this.unitFee.setScale(8);
-		this.minFeePerByte = this.unitFee.divide(this.maxBytesPerUnitFee, MathContext.DECIMAL32);
-
-		// Pre-calculate cumulative blocks required for each level
+		// Calculate cumulative blocks required for each level
 		int cumulativeBlocks = 0;
 		this.cumulativeBlocksByLevel = new ArrayList<>(this.blocksNeededByLevel.size() + 1);
 		for (int level = 0; level <= this.blocksNeededByLevel.size(); ++level) {
@@ -462,6 +462,17 @@ public class BlockChain {
 				cumulativeBlocks += this.blocksNeededByLevel.get(level);
 		}
 
+		// Generate lookup-array for account-level share bins
+		AccountLevelShareBin lastAccountLevelShareBin = this.sharesByLevel.get(this.sharesByLevel.size() - 1);
+		final int lastLevel = lastAccountLevelShareBin.levels.get(lastAccountLevelShareBin.levels.size() - 1);
+		this.shareBinsByLevel = new AccountLevelShareBin[lastLevel];
+
+		for (AccountLevelShareBin accountLevelShareBin : this.sharesByLevel)
+			for (int level : accountLevelShareBin.levels)
+				// level 1 stored at index 0, level 2 stored at index 1, etc.
+				// level 0 not allowed
+				this.shareBinsByLevel[level - 1] = accountLevelShareBin;
+
 		// Convert collections to unmodifiable form
 		this.rewardsByHeight = Collections.unmodifiableList(this.rewardsByHeight);
 		this.sharesByLevel = Collections.unmodifiableList(this.sharesByLevel);
@@ -499,7 +510,7 @@ public class BlockChain {
 		}
 	}
 
-	private static boolean isGenesisBlockValid() throws DataException {
+	private static boolean isGenesisBlockValid() {
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			BlockRepository blockRepository = repository.getBlockRepository();
 
@@ -512,6 +523,8 @@ public class BlockChain {
 				return false;
 
 			return GenesisBlock.isGenesisBlock(blockData);
+		} catch (DataException e) {
+			return false;
 		}
 	}
 

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

@@ -5,6 +5,7 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.stream.Collectors;
 
@@ -39,6 +40,8 @@ public class BlockMinter extends Thread {
 
 	// Other properties
 	private static final Logger LOGGER = LogManager.getLogger(BlockMinter.class);
+	private static Long lastLogTimestamp;
+	private static Long logTimeout;
 
 	// Constructors
 
@@ -75,20 +78,15 @@ public class BlockMinter extends Thread {
 			boolean isMintingPossible = false;
 			boolean wasMintingPossible = isMintingPossible;
 			while (running) {
+				repository.discardChanges(); // Free repository locks, if any
+
+				if (isMintingPossible != wasMintingPossible)
+					Controller.getInstance().onMintingPossibleChange(isMintingPossible);
+
+				wasMintingPossible = isMintingPossible;
+
 				// Sleep for a while
-				try {
-					repository.discardChanges(); // Free repository locks, if any
-
-					if (isMintingPossible != wasMintingPossible)
-						Controller.getInstance().onMintingPossibleChange(isMintingPossible);
-
-					wasMintingPossible = isMintingPossible;
-
-					Thread.sleep(1000);
-				} catch (InterruptedException e) {
-					// We've been interrupted - time to exit
-					return;
-				}
+				Thread.sleep(1000);
 
 				isMintingPossible = false;
 
@@ -130,7 +128,7 @@ public class BlockMinter extends Thread {
 					}
 				}
 
-				List<Peer> peers = Network.getInstance().getUniqueHandshakedPeers();
+				List<Peer> peers = Network.getInstance().getHandshakedPeers();
 				BlockData lastBlockData = blockRepository.getLastBlock();
 
 				// Disregard peers that have "misbehaved" recently
@@ -155,6 +153,9 @@ public class BlockMinter extends Thread {
 				if (previousBlock == null || !Arrays.equals(previousBlock.getSignature(), lastBlockData.getSignature())) {
 					previousBlock = new Block(repository, lastBlockData);
 					newBlocks.clear();
+
+					// Reduce log timeout
+					logTimeout = 10 * 1000L;
 				}
 
 				// Discard accounts we have already built blocks with
@@ -167,11 +168,23 @@ public class BlockMinter extends Thread {
 					// First block does the AT heavy-lifting
 					if (newBlocks.isEmpty()) {
 						Block newBlock = Block.mint(repository, previousBlock.getBlockData(), mintingAccount);
+						if (newBlock == null) {
+							// For some reason we can't mint right now
+							moderatedLog(() -> LOGGER.error("Couldn't build a to-be-minted block"));
+							continue;
+						}
+
 						newBlocks.add(newBlock);
 					} else {
 						// The blocks for other minters require less effort...
-						Block newBlock = newBlocks.get(0);
-						newBlocks.add(newBlock.remint(mintingAccount));
+						Block newBlock = newBlocks.get(0).remint(mintingAccount);
+						if (newBlock == null) {
+							// For some reason we can't mint right now
+							moderatedLog(() -> LOGGER.error("Couldn't rebuild a to-be-minted block"));
+							continue;
+						}
+
+						newBlocks.add(newBlock);
 					}
 				}
 
@@ -181,15 +194,23 @@ public class BlockMinter extends Thread {
 
 				// Make sure we're the only thread modifying the blockchain
 				ReentrantLock blockchainLock = Controller.getInstance().getBlockchainLock();
-				if (!blockchainLock.tryLock())
+				if (!blockchainLock.tryLock(30, TimeUnit.SECONDS)) {
+					LOGGER.warn("Couldn't acquire blockchain lock even after waiting 30 seconds");
 					continue;
+				}
 
 				boolean newBlockMinted = false;
+				Block newBlock = null;
 
 				try {
-					// Clear repository's "in transaction" state so we don't cause a repository deadlock
+					// Clear repository session state so we have latest view of data
 					repository.discardChanges();
 
+					// Now that we have blockchain lock, do final check that chain hasn't changed
+					BlockData latestBlockData = blockRepository.getLastBlock();
+					if (!Arrays.equals(lastBlockData.getSignature(), latestBlockData.getSignature()))
+						continue;
+
 					List<Block> goodBlocks = new ArrayList<>();
 					for (Block testBlock : newBlocks) {
 						// Is new block's timestamp valid yet?
@@ -198,8 +219,12 @@ public class BlockMinter extends Thread {
 							continue;
 
 						// Is new block valid yet? (Before adding unconfirmed transactions)
-						if (testBlock.isValid() != ValidationResult.OK)
+						ValidationResult result = testBlock.isValid();
+						if (result != ValidationResult.OK) {
+							moderatedLog(() -> LOGGER.error(String.format("To-be-minted block invalid '%s' before adding transactions?", result.name())));
+
 							continue;
+						}
 
 						goodBlocks.add(testBlock);
 					}
@@ -211,7 +236,6 @@ public class BlockMinter extends Thread {
 					final int parentHeight = previousBlock.getBlockData().getHeight();
 					final byte[] parentBlockSignature = previousBlock.getSignature();
 
-					Block newBlock = null;
 					BigInteger bestWeight = null;
 
 					for (int bi = 0; bi < goodBlocks.size(); ++bi) {
@@ -282,10 +306,13 @@ public class BlockMinter extends Thread {
 				}
 
 				if (newBlockMinted)
-					Controller.getInstance().onBlockMinted();
+					Controller.getInstance().onNewBlock(newBlock.getBlockData());
 			}
 		} catch (DataException e) {
 			LOGGER.warn("Repository issue while running block minter", e);
+		} catch (InterruptedException e) {
+			// We've been interrupted - time to exit
+			return;
 		}
 	}
 
@@ -338,19 +365,21 @@ public class BlockMinter extends Thread {
 		this.interrupt();
 	}
 
-	public static void mintTestingBlock(Repository repository, PrivateKeyAccount... mintingAndOnlineAccounts) throws DataException {
-		if (!BlockChain.getInstance().isTestChain()) {
-			LOGGER.warn("Ignoring attempt to mint testing block for non-test chain!");
-			return;
-		}
+	public static Block mintTestingBlock(Repository repository, PrivateKeyAccount... mintingAndOnlineAccounts) throws DataException {
+		if (!BlockChain.getInstance().isTestChain())
+			throw new DataException("Ignoring attempt to mint testing block for non-test chain!");
 
 		// Ensure mintingAccount is 'online' so blocks can be minted
 		Controller.getInstance().ensureTestingAccountsOnline(mintingAndOnlineAccounts);
 
-		BlockData previousBlockData = repository.getBlockRepository().getLastBlock();
-
 		PrivateKeyAccount mintingAccount = mintingAndOnlineAccounts[0];
 
+		return mintTestingBlockRetainingTimestamps(repository, mintingAccount);
+	}
+
+	public static Block mintTestingBlockRetainingTimestamps(Repository repository, PrivateKeyAccount mintingAccount) throws DataException {
+		BlockData previousBlockData = repository.getBlockRepository().getLastBlock();
+
 		Block newBlock = Block.mint(repository, previousBlockData, mintingAccount);
 
 		// Make sure we're the only thread modifying the blockchain
@@ -373,9 +402,22 @@ public class BlockMinter extends Thread {
 			LOGGER.info(String.format("Minted new test block: %d", newBlock.getBlockData().getHeight()));
 
 			repository.saveChanges();
+
+			return newBlock;
 		} finally {
 			blockchainLock.unlock();
 		}
 	}
 
+	private static void moderatedLog(Runnable logFunction) {
+		// We only log if logging at TRACE or previous log timeout has expired
+		if (!LOGGER.isTraceEnabled() && lastLogTimestamp != null && lastLogTimestamp + logTimeout > System.currentTimeMillis())
+			return;
+
+		lastLogTimestamp = System.currentTimeMillis();
+		logTimeout = 2 * 60 * 1000L; // initial timeout, can be reduced if new block appears
+
+		logFunction.run();
+	}
+
 }

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

@@ -2,32 +2,25 @@ package org.qortal.block;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.math.BigDecimal;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
-import java.util.stream.Collectors;
 
 import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.qortal.account.Account;
-import org.qortal.account.GenesisAccount;
-import org.qortal.account.PublicKeyAccount;
+import org.qortal.account.NullAccount;
 import org.qortal.crypto.Crypto;
 import org.qortal.data.asset.AssetData;
 import org.qortal.data.block.BlockData;
-import org.qortal.data.transaction.IssueAssetTransactionData;
 import org.qortal.data.transaction.TransactionData;
-import org.qortal.group.Group;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
 import org.qortal.transaction.Transaction;
 import org.qortal.transaction.Transaction.ApprovalStatus;
-import org.qortal.transaction.Transaction.TransactionType;
 import org.qortal.transform.TransformationException;
 import org.qortal.transform.transaction.TransactionTransformer;
 
@@ -39,9 +32,8 @@ public class GenesisBlock extends Block {
 
 	private static final Logger LOGGER = LogManager.getLogger(GenesisBlock.class);
 
-	private static final byte[] GENESIS_REFERENCE = new byte[] {
-		1, 1, 1, 1, 1, 1, 1, 1
-	}; // NOTE: Neither 64 nor 128 bytes!
+	private static final byte[] GENESIS_BLOCK_REFERENCE = new byte[128];
+	private static final byte[] GENESIS_TRANSACTION_REFERENCE = new byte[64];
 
 	@XmlAccessorType(XmlAccessType.FIELD)
 	public static class GenesisInfo {
@@ -93,46 +85,25 @@ public class GenesisBlock extends Block {
 		// Add default values to transactions
 		transactionsData.stream().forEach(transactionData -> {
 			if (transactionData.getFee() == null)
-				transactionData.setFee(BigDecimal.ZERO.setScale(8));
+				transactionData.setFee(0L);
 
 			if (transactionData.getCreatorPublicKey() == null)
-				transactionData.setCreatorPublicKey(GenesisAccount.PUBLIC_KEY);
+				transactionData.setCreatorPublicKey(NullAccount.PUBLIC_KEY);
 
 			if (transactionData.getTimestamp() == 0)
 				transactionData.setTimestamp(info.timestamp);
 		});
 
-		// For version 1, extract any ISSUE_ASSET transactions into initialAssets and only allow GENESIS transactions
-		if (info.version == 1) {
-			List<TransactionData> issueAssetTransactions = transactionsData.stream()
-					.filter(transactionData -> transactionData.getType() == TransactionType.ISSUE_ASSET).collect(Collectors.toList());
-			transactionsData.removeAll(issueAssetTransactions);
-
-			// There should be only GENESIS transactions left;
-			if (transactionsData.stream().anyMatch(transactionData -> transactionData.getType() != TransactionType.GENESIS)) {
-				LOGGER.error("Version 1 genesis block only allowed to contain GENESIS transctions (after issue-asset processing)");
-				throw new RuntimeException("Version 1 genesis block only allowed to contain GENESIS transctions (after issue-asset processing)");
-			}
-
-			// Convert ISSUE_ASSET transactions into initial assets
-			initialAssets = issueAssetTransactions.stream().map(transactionData -> {
-				IssueAssetTransactionData issueAssetTransactionData = (IssueAssetTransactionData) transactionData;
-
-				return new AssetData(issueAssetTransactionData.getOwner(), issueAssetTransactionData.getAssetName(), issueAssetTransactionData.getDescription(),
-						issueAssetTransactionData.getQuantity(), issueAssetTransactionData.getIsDivisible(), "", false, Group.NO_GROUP, issueAssetTransactionData.getReference());
-			}).collect(Collectors.toList());
-		}
-
-		byte[] reference = GENESIS_REFERENCE;
+		byte[] reference = GENESIS_BLOCK_REFERENCE;
 		int transactionCount = transactionsData.size();
-		BigDecimal totalFees = BigDecimal.ZERO.setScale(8);
-		byte[] minterPublicKey = GenesisAccount.PUBLIC_KEY;
+		long totalFees = 0;
+		byte[] minterPublicKey = NullAccount.PUBLIC_KEY;
 		byte[] bytesForSignature = getBytesForMinterSignature(info.timestamp, reference, minterPublicKey);
 		byte[] minterSignature = calcGenesisMinterSignature(bytesForSignature);
 		byte[] transactionsSignature = calcGenesisTransactionsSignature();
 		int height = 1;
 		int atCount = 0;
-		BigDecimal atFees = BigDecimal.ZERO.setScale(8);
+		long atFees = 0;
 
 		genesisBlockData = new BlockData(info.version, reference, transactionCount, totalFees, transactionsSignature, height, info.timestamp,
 				minterPublicKey, minterSignature, atCount, atFees);
@@ -172,7 +143,7 @@ public class GenesisBlock extends Block {
 	/**
 	 * Refuse to calculate genesis block's minter signature!
 	 * <p>
-	 * This is not possible as there is no private key for the genesis account and so no way to sign data.
+	 * This is not possible as there is no private key for the null account and so no way to sign data.
 	 * <p>
 	 * <b>Always throws IllegalStateException.</b>
 	 * 
@@ -180,13 +151,13 @@ public class GenesisBlock extends Block {
 	 */
 	@Override
 	public void calcMinterSignature() {
-		throw new IllegalStateException("There is no private key for genesis account");
+		throw new IllegalStateException("There is no private key for null account");
 	}
 
 	/**
 	 * Refuse to calculate genesis block's transactions signature!
 	 * <p>
-	 * This is not possible as there is no private key for the genesis account and so no way to sign data.
+	 * This is not possible as there is no private key for the null account and so no way to sign data.
 	 * <p>
 	 * <b>Always throws IllegalStateException.</b>
 	 * 
@@ -194,13 +165,13 @@ public class GenesisBlock extends Block {
 	 */
 	@Override
 	public void calcTransactionsSignature() {
-		throw new IllegalStateException("There is no private key for genesis account");
+		throw new IllegalStateException("There is no private key for null account");
 	}
 
 	/**
 	 * Generate genesis block minter signature.
 	 * <p>
-	 * This is handled differently as there is no private key for the genesis account and so no way to sign data.
+	 * This is handled differently as there is no private key for the null account and so no way to sign data.
 	 * 
 	 * @return byte[]
 	 */
@@ -212,24 +183,16 @@ public class GenesisBlock extends Block {
 		try {
 			// Passing expected size to ByteArrayOutputStream avoids reallocation when adding more bytes than default 32.
 			// See below for explanation of some of the values used to calculated expected size.
-			ByteArrayOutputStream bytes = new ByteArrayOutputStream(8 + 64 + 8 + 32);
+			ByteArrayOutputStream bytes = new ByteArrayOutputStream(8 + 128 + 32);
 
-			/*
-			 * NOTE: Historic code had genesis block using Longs.toByteArray(version) compared to standard block's Ints.toByteArray. The subsequent
-			 * Bytes.ensureCapacity(versionBytes, 0, 4) did not truncate versionBytes back to 4 bytes either. This means 8 bytes were used even though
-			 * VERSION_LENGTH is set to 4. Correcting this historic bug will break genesis block signatures!
-			 */
-			// For Qortal, we use genesis timestamp instead
+			// Genesis block timestamp
 			bytes.write(Longs.toByteArray(timestamp));
 
-			/*
-			 * NOTE: Historic code had the reference expanded to only 64 bytes whereas standard block references are 128 bytes. Correcting this historic bug
-			 * will break genesis block signatures!
-			 */
-			bytes.write(Bytes.ensureCapacity(reference, 64, 0));
+			// Block's reference
+			bytes.write(reference);
 
-			// NOTE: Genesis account's public key is only 8 bytes, not the usual 32, so we have to pad.
-			bytes.write(Bytes.ensureCapacity(minterPublicKey, 32, 0));
+			// Minting account's public key (typically NullAccount)
+			bytes.write(minterPublicKey);
 
 			return bytes.toByteArray();
 		} catch (IOException e) {
@@ -295,26 +258,18 @@ public class GenesisBlock extends Block {
 	public void process() throws DataException {
 		LOGGER.info(String.format("Using genesis block timestamp of %d", this.blockData.getTimestamp()));
 
-		// If we're a version 1 genesis block, create assets now
-		if (this.blockData.getVersion() == 1)
-			for (AssetData assetData : initialAssets)
-				repository.getAssetRepository().save(assetData);
-
 		/*
 		 * Some transactions will be missing references and signatures,
-		 * so we generate them by trial-processing transactions and using
-		 * account's last-reference to fill in the gaps for reference,
+		 * so we generate them by using <tt>GENESIS_TRANSACTION_REFERENCE</tt>
 		 * and a duplicated SHA256 digest for signature
 		 */
-		this.repository.setSavepoint();
 		try {
 			for (Transaction transaction : this.getTransactions()) {
 				TransactionData transactionData = transaction.getTransactionData();
-				Account creator = new PublicKeyAccount(this.repository, transactionData.getCreatorPublicKey());
 
 				// Missing reference?
 				if (transactionData.getReference() == null)
-					transactionData.setReference(creator.getLastReference());
+					transactionData.setReference(GENESIS_TRANSACTION_REFERENCE);
 
 				// Missing signature?
 				if (transactionData.getSignature() == null) {
@@ -324,24 +279,21 @@ public class GenesisBlock extends Block {
 					transactionData.setSignature(signature);
 				}
 
-				// Missing approval status (not used in V1)
+				// Approval status
 				transactionData.setApprovalStatus(ApprovalStatus.NOT_REQUIRED);
-
-				// Ask transaction to update references, etc.
-				transaction.processReferencesAndFees();
-
-				creator.setLastReference(transactionData.getSignature());
 			}
 		} catch (TransformationException e) {
 			throw new RuntimeException("Can't process genesis block transaction", e);
-		} finally {
-			this.repository.rollbackToSavepoint();
 		}
 
 		// Save transactions into repository ready for processing
 		for (Transaction transaction : this.getTransactions())
 			this.repository.getTransactionRepository().save(transaction.getTransactionData());
 
+		// No ATs in genesis block
+		this.ourAtStates = Collections.emptyList();
+		this.ourAtFees = 0;
+
 		super.process();
 	}
 

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

@@ -0,0 +1,61 @@
+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 {
+
+	private static BlockNotifier instance;
+
+	@FunctionalInterface
+	public interface Listener {
+		void notify(BlockInfo blockInfo);
+	}
+
+	private Map<Session, Listener> listenersBySession = new HashMap<>();
+
+	private BlockNotifier() {
+	}
+
+	public static synchronized BlockNotifier getInstance() {
+		if (instance == null)
+			instance = new BlockNotifier();
+
+		return instance;
+	}
+
+	public void register(Session session, Listener listener) {
+		synchronized (this.listenersBySession) {
+			this.listenersBySession.put(session, listener);
+		}
+	}
+
+	public void deregister(Session session) {
+		synchronized (this.listenersBySession) {
+			this.listenersBySession.remove(session);
+		}
+	}
+
+	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

@@ -0,0 +1,62 @@
+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.data.transaction.ChatTransactionData;
+
+public class ChatNotifier {
+
+	private static ChatNotifier instance;
+
+	@FunctionalInterface
+	public interface Listener {
+		void notify(ChatTransactionData chatTransactionData);
+	}
+
+	private Map<Session, Listener> listenersBySession = new HashMap<>();
+
+	private ChatNotifier() {
+	}
+
+	public static synchronized ChatNotifier getInstance() {
+		if (instance == null)
+			instance = new ChatNotifier();
+
+		return instance;
+	}
+
+	public void register(Session session, Listener listener) {
+		synchronized (this.listenersBySession) {
+			this.listenersBySession.put(session, listener);
+		}
+	}
+
+	public void deregister(Session session) {
+		synchronized (this.listenersBySession) {
+			this.listenersBySession.remove(session);
+		}
+	}
+
+	public void onNewChatTransaction(ChatTransactionData chatTransactionData) {
+		for (Listener listener : getAllListeners())
+			listener.notify(chatTransactionData);
+	}
+
+	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

@@ -18,6 +18,8 @@ import java.util.List;
 import java.util.Map;
 import java.util.Properties;
 import java.util.Random;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
@@ -46,6 +48,7 @@ import org.qortal.data.network.PeerData;
 import org.qortal.data.transaction.ArbitraryTransactionData;
 import org.qortal.data.transaction.TransactionData;
 import org.qortal.data.transaction.ArbitraryTransactionData.DataType;
+import org.qortal.data.transaction.ChatTransactionData;
 import org.qortal.globalization.Translator;
 import org.qortal.gui.Gui;
 import org.qortal.gui.SysTray;
@@ -59,11 +62,9 @@ import org.qortal.network.message.GetBlockMessage;
 import org.qortal.network.message.GetBlockSummariesMessage;
 import org.qortal.network.message.GetOnlineAccountsMessage;
 import org.qortal.network.message.GetPeersMessage;
-import org.qortal.network.message.GetSignaturesMessage;
 import org.qortal.network.message.GetSignaturesV2Message;
 import org.qortal.network.message.GetTransactionMessage;
 import org.qortal.network.message.GetUnconfirmedTransactionsMessage;
-import org.qortal.network.message.HeightMessage;
 import org.qortal.network.message.HeightV2Message;
 import org.qortal.network.message.Message;
 import org.qortal.network.message.OnlineAccountsMessage;
@@ -124,6 +125,9 @@ public class Controller extends Thread {
 	private final long buildTimestamp; // seconds
 	private final String[] savedArgs;
 
+	private ExecutorService callbackExecutor = Executors.newFixedThreadPool(3);
+	private volatile boolean notifyGroupMembershipChange = false;
+
 	private volatile BlockData chainTip = null;
 
 	private long repositoryBackupTimestamp = startTime; // ms
@@ -136,6 +140,8 @@ public class Controller extends Thread {
 
 	/** Whether we are attempting to synchronize. */
 	private volatile boolean isSynchronizing = false;
+	/** Temporary estimate of synchronization progress for SysTray use. */
+	private volatile int syncPercent = 0;
 
 	/** Latest block signatures from other peers that we know are on inferior chains. */
 	List<ByteArray> inferiorChainSignatures = new ArrayList<>();
@@ -232,7 +238,7 @@ public class Controller extends Thread {
 		return this.chainTip;
 	}
 
-	/** Cache new blockchain tip, and also wipe cache of online accounts. */
+	/** Cache new blockchain tip. */
 	public void setChainTip(BlockData blockData) {
 		this.chainTip = blockData;
 	}
@@ -258,6 +264,10 @@ public class Controller extends Thread {
 		return this.isSynchronizing;
 	}
 
+	public Integer getSyncPercent() {
+		return this.isSynchronizing ? this.syncPercent : null;
+	}
+
 	// Entry point
 
 	public static void main(String[] args) {
@@ -330,7 +340,7 @@ public class Controller extends Thread {
 		try {
 			Network network = Network.getInstance();
 			network.start();
-		} catch (IOException e) {
+		} catch (IOException | DataException e) {
 			LOGGER.error("Unable to start networking", e);
 			Controller.getInstance().shutdown();
 			Gui.getInstance().fatalError("Networking failure", e);
@@ -494,7 +504,7 @@ public class Controller extends Thread {
 	};
 
 	private void potentiallySynchronize() throws InterruptedException {
-		List<Peer> peers = Network.getInstance().getUniqueHandshakedPeers();
+		List<Peer> peers = Network.getInstance().getHandshakedPeers();
 
 		// Disregard peers that have "misbehaved" recently
 		peers.removeIf(hasMisbehaved);
@@ -522,102 +532,95 @@ public class Controller extends Thread {
 		int index = new SecureRandom().nextInt(peers.size());
 		Peer peer = peers.get(index);
 
-		isSynchronizing = true;
-		updateSysTray();
-
 		actuallySynchronize(peer, false);
-
-		isSynchronizing = false;
-		requestSysTrayUpdate = true;
 	}
 
 	public SynchronizationResult actuallySynchronize(Peer peer, boolean force) throws InterruptedException {
-		BlockData latestBlockData = getChainTip();
-
-		SynchronizationResult syncResult = Synchronizer.getInstance().synchronize(peer, force);
-		switch (syncResult) {
-			case GENESIS_ONLY:
-			case NO_COMMON_BLOCK:
-			case TOO_DIVERGENT:
-			case INVALID_DATA: {
-				// These are more serious results that warrant a cool-off
-				LOGGER.info(String.format("Failed to synchronize with peer %s (%s) - cooling off", peer, syncResult.name()));
-
-				// Don't use this peer again for a while
-				PeerData peerData = peer.getPeerData();
-				peerData.setLastMisbehaved(NTP.getTime());
-
-				// Only save to repository if outbound peer
-				if (peer.isOutbound())
-					try (final Repository repository = RepositoryManager.getRepository()) {
-						repository.getNetworkRepository().save(peerData);
-						repository.saveChanges();
-					} catch (DataException e) {
-						LOGGER.warn("Repository issue while updating peer synchronization info", e);
-					}
-				break;
-			}
-
-			case INFERIOR_CHAIN: {
-				// Update our list of inferior chain tips
-				ByteArray inferiorChainSignature = new ByteArray(peer.getChainTipData().getLastBlockSignature());
-				if (!inferiorChainSignatures.contains(inferiorChainSignature))
-					inferiorChainSignatures.add(inferiorChainSignature);
-
-				// These are minor failure results so fine to try again
-				LOGGER.debug(() -> String.format("Refused to synchronize with peer %s (%s)", peer, syncResult.name()));
-
-				// Notify peer of our superior chain
-				if (!peer.sendMessage(Network.getInstance().buildHeightMessage(peer, latestBlockData)))
-					peer.disconnect("failed to notify peer of our superior chain");
-				break;
-			}
-
-			case NO_REPLY:
-			case NO_BLOCKCHAIN_LOCK:
-			case REPOSITORY_ISSUE:
-				// These are minor failure results so fine to try again
-				LOGGER.debug(() -> String.format("Failed to synchronize with peer %s (%s)", peer, syncResult.name()));
-				break;
-
-			case SHUTTING_DOWN:
-				// Just quietly exit
-				break;
-
-			case OK:
-				requestSysTrayUpdate = true;
-				// fall-through...
-			case NOTHING_TO_DO: {
-				// Update our list of inferior chain tips
-				ByteArray inferiorChainSignature = new ByteArray(peer.getChainTipData().getLastBlockSignature());
-				if (!inferiorChainSignatures.contains(inferiorChainSignature))
-					inferiorChainSignatures.add(inferiorChainSignature);
-
-				LOGGER.debug(() -> String.format("Synchronized with peer %s (%s)", peer, syncResult.name()));
-				break;
-			}
+		syncPercent = (this.chainTip.getHeight() * 100) / peer.getChainTipData().getLastHeight();
+		// Only update SysTray if we're potentially changing height
+		if (syncPercent < 100) {
+			isSynchronizing = true;
+			updateSysTray();
 		}
 
-		// Has our chain tip changed?
-		BlockData newLatestBlockData;
+		BlockData priorChainTip = this.chainTip;
+
+		try {
+			SynchronizationResult syncResult = Synchronizer.getInstance().synchronize(peer, force);
+			switch (syncResult) {
+				case GENESIS_ONLY:
+				case NO_COMMON_BLOCK:
+				case TOO_DIVERGENT:
+				case INVALID_DATA: {
+					// These are more serious results that warrant a cool-off
+					LOGGER.info(String.format("Failed to synchronize with peer %s (%s) - cooling off", peer, syncResult.name()));
+
+					// Don't use this peer again for a while
+					Network.getInstance().peerMisbehaved(peer);
+					break;
+				}
+
+				case INFERIOR_CHAIN: {
+					// Update our list of inferior chain tips
+					ByteArray inferiorChainSignature = new ByteArray(peer.getChainTipData().getLastBlockSignature());
+					if (!inferiorChainSignatures.contains(inferiorChainSignature))
+						inferiorChainSignatures.add(inferiorChainSignature);
+
+					// These are minor failure results so fine to try again
+					LOGGER.debug(() -> String.format("Refused to synchronize with peer %s (%s)", peer, syncResult.name()));
+
+					// Notify peer of our superior chain
+					if (!peer.sendMessage(Network.getInstance().buildHeightMessage(peer, priorChainTip)))
+						peer.disconnect("failed to notify peer of our superior chain");
+					break;
+				}
+
+				case NO_REPLY:
+				case NO_BLOCKCHAIN_LOCK:
+				case REPOSITORY_ISSUE:
+					// These are minor failure results so fine to try again
+					LOGGER.debug(() -> String.format("Failed to synchronize with peer %s (%s)", peer, syncResult.name()));
+					break;
+
+				case SHUTTING_DOWN:
+					// Just quietly exit
+					break;
+
+				case OK:
+					// fall-through...
+				case NOTHING_TO_DO: {
+					// Update our list of inferior chain tips
+					ByteArray inferiorChainSignature = new ByteArray(peer.getChainTipData().getLastBlockSignature());
+					if (!inferiorChainSignatures.contains(inferiorChainSignature))
+						inferiorChainSignatures.add(inferiorChainSignature);
+
+					LOGGER.debug(() -> String.format("Synchronized with peer %s (%s)", peer, syncResult.name()));
+					break;
+				}
+			}
+
+			// Has our chain tip changed?
+			BlockData newChainTip;
+
+			try (final Repository repository = RepositoryManager.getRepository()) {
+				newChainTip = repository.getBlockRepository().getLastBlock();
+			} catch (DataException e) {
+				LOGGER.warn(String.format("Repository issue when trying to fetch post-synchronization chain tip: %s", e.getMessage()));
+				return syncResult;
+			}
+
+			if (!Arrays.equals(newChainTip.getSignature(), priorChainTip.getSignature())) {
+				// Reset our cache of inferior chains
+				inferiorChainSignatures.clear();
+
+				// Update chain-tip, systray, notify peers, websockets, etc.
+				this.onNewBlock(newChainTip);
+			}
 
-		try (final Repository repository = RepositoryManager.getRepository()) {
-			newLatestBlockData = repository.getBlockRepository().getLastBlock();
-			this.setChainTip(newLatestBlockData);
-		} catch (DataException e) {
-			LOGGER.warn(String.format("Repository issue when trying to fetch post-synchronization chain tip: %s", e.getMessage()));
 			return syncResult;
+		} finally {
+			isSynchronizing = false;
 		}
-
-		if (!Arrays.equals(newLatestBlockData.getSignature(), latestBlockData.getSignature())) {
-			// Broadcast our new chain tip
-			Network.getInstance().broadcast(recipientPeer -> Network.getInstance().buildHeightMessage(recipientPeer, newLatestBlockData));
-
-			// Reset our cache of inferior chains
-			inferiorChainSignatures.clear();
-		}
-
-		return syncResult;
 	}
 
 	private void updateSysTray() {
@@ -626,24 +629,29 @@ public class Controller extends Thread {
 			return;
 		}
 
-		final int numberOfPeers = Network.getInstance().getUniqueHandshakedPeers().size();
+		final int numberOfPeers = Network.getInstance().getHandshakedPeers().size();
 
 		final int height = getChainHeight();
 
 		String connectionsText = Translator.INSTANCE.translate("SysTray", numberOfPeers != 1 ? "CONNECTIONS" : "CONNECTION");
 		String heightText = Translator.INSTANCE.translate("SysTray", "BLOCK_HEIGHT");
 
-		String actionKey;
+		String actionText;
 		if (isMintingPossible)
-			actionKey = "MINTING_ENABLED";
+			actionText = Translator.INSTANCE.translate("SysTray", "MINTING_ENABLED");
 		else if (isSynchronizing)
-			actionKey = "SYNCHRONIZING_BLOCKCHAIN";
+			actionText = String.format("%s - %d%%", Translator.INSTANCE.translate("SysTray", "SYNCHRONIZING_BLOCKCHAIN"), syncPercent);
+		else if (numberOfPeers < Settings.getInstance().getMinBlockchainPeers())
+			actionText = Translator.INSTANCE.translate("SysTray", "CONNECTING");
 		else
-			actionKey = "MINTING_DISABLED";
-		String actionText = Translator.INSTANCE.translate("SysTray", actionKey);
+			actionText = Translator.INSTANCE.translate("SysTray", "MINTING_DISABLED");
 
 		String tooltip = String.format("%s - %d %s - %s %d", actionText, numberOfPeers, connectionsText, heightText, height);
 		SysTray.getInstance().setToolTipText(tooltip);
+
+		this.callbackExecutor.execute(() -> {
+			StatusNotifier.getInstance().onStatusChange(NTP.getTime());
+		});
 	}
 
 	public void deleteExpiredTransactions() {
@@ -730,6 +738,22 @@ public class Controller extends Thread {
 		System.exit(0);
 	}
 
+	// Callbacks
+
+	public void onGroupMembershipChange(int groupId) {
+		/*
+		 * We've likely been called in the middle of block processing,
+		 * so set a flag for now as other repository sessions won't 'see'
+		 * the group membership change until a call to repository.saveChanges().
+		 * 
+		 * Eventually, onNewBlock() will be executed and queue a callback task.
+		 * This callback task will check the flag and notify websocket listeners, etc.
+		 * and those listeners will be post-saveChanges() and hence see the new
+		 * group membership state.
+		 */
+		this.notifyGroupMembershipChange = true;
+	}
+
 	// Callbacks for/from network
 
 	public void doNetworkBroadcast() {
@@ -742,8 +766,10 @@ 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) {
@@ -751,59 +777,44 @@ public class Controller extends Thread {
 		requestSysTrayUpdate = true;
 	}
 
-	public void onBlockMinted() {
-		// Broadcast our new height info
-		BlockData latestBlockData;
-
-		try (final Repository repository = RepositoryManager.getRepository()) {
-			latestBlockData = repository.getBlockRepository().getLastBlock();
-			this.setChainTip(latestBlockData);
-		} catch (DataException e) {
-			LOGGER.warn(String.format("Repository issue when trying to fetch post-mint chain tip: %s", e.getMessage()));
-			return;
-		}
-
-		Network network = Network.getInstance();
-		network.broadcast(peer -> network.buildHeightMessage(peer, latestBlockData));
-
+	public void onNewBlock(BlockData latestBlockData) {
+		this.setChainTip(latestBlockData);
 		requestSysTrayUpdate = true;
+
+		// Broadcast our new height info and notify websocket listeners
+		this.callbackExecutor.execute(() -> {
+			Network network = Network.getInstance();
+			network.broadcast(peer -> network.buildHeightMessage(peer, latestBlockData));
+
+			BlockNotifier.getInstance().onNewBlock(latestBlockData);
+
+			if (this.notifyGroupMembershipChange) {
+				this.notifyGroupMembershipChange = false;
+				ChatNotifier.getInstance().onGroupMembershipChange();
+			}
+		});
 	}
 
-	public void onNewTransaction(TransactionData transactionData) {
-		// Send round to all peers
-		Network network = Network.getInstance();
-		network.broadcast(peer -> network.buildNewTransactionMessage(peer, transactionData));
+	/** Callback for when we've received a new transaction via API or peer. */
+	public void onNewTransaction(TransactionData transactionData, Peer peer) {
+		this.callbackExecutor.execute(() -> {
+			// Notify all peers (except maybe peer that sent it to us if applicable)
+			Network.getInstance().broadcast(broadcastPeer -> broadcastPeer == peer ? null : new TransactionSignaturesMessage(Arrays.asList(transactionData.getSignature())));
+
+			// If this is a CHAT transaction, there may be extra listeners to notify
+			if (transactionData.getType() == TransactionType.CHAT)
+				ChatNotifier.getInstance().onNewChatTransaction((ChatTransactionData) transactionData);
+		});
 	}
 
 	public void onPeerHandshakeCompleted(Peer peer) {
 		// Only send if outbound
 		if (peer.isOutbound()) {
-			if (peer.getVersion() < 2) {
-				// Legacy mode
-
-				// Send our unconfirmed transactions
-				try (final Repository repository = RepositoryManager.getRepository()) {
-					List<TransactionData> transactions = repository.getTransactionRepository().getUnconfirmedTransactions();
-
-					for (TransactionData transactionData : transactions) {
-						Message transactionMessage = new TransactionMessage(transactionData);
-						if (!peer.sendMessage(transactionMessage)) {
-							peer.disconnect("failed to send unconfirmed transaction");
-							return;
-						}
-					}
-				} catch (DataException e) {
-					LOGGER.error("Repository issue while sending unconfirmed transactions", e);
-				}
-			} else {
-				// V2 protocol
-
-				// Request peer's unconfirmed transactions
-				Message message = new GetUnconfirmedTransactionsMessage();
-				if (!peer.sendMessage(message)) {
-					peer.disconnect("failed to send request for unconfirmed transactions");
-					return;
-				}
+			// Request peer's unconfirmed transactions
+			Message message = new GetUnconfirmedTransactionsMessage();
+			if (!peer.sendMessage(message)) {
+				peer.disconnect("failed to send request for unconfirmed transactions");
+				return;
 			}
 		}
 
@@ -819,22 +830,10 @@ public class Controller extends Thread {
 
 		// Ordered by message type value
 		switch (message.getType()) {
-			case HEIGHT:
-				onNetworkHeightMessage(peer, message);
-				break;
-
-			case GET_SIGNATURES:
-				onNetworkGetSignaturesMessage(peer, message);
-				break;
-
 			case GET_BLOCK:
 				onNetworkGetBlockMessage(peer, message);
 				break;
 
-			case BLOCK:
-				onNetworkBlockMessage(peer, message);
-				break;
-
 			case TRANSACTION:
 				onNetworkTransactionMessage(peer, message);
 				break;
@@ -880,56 +879,11 @@ public class Controller extends Thread {
 				break;
 
 			default:
-				LOGGER.debug(String.format("Unhandled %s message [ID %d] from peer %s", message.getType().name(), message.getId(), peer));
+				LOGGER.debug(() -> String.format("Unhandled %s message [ID %d] from peer %s", message.getType().name(), message.getId(), peer));
 				break;
 		}
 	}
 
-	private void onNetworkHeightMessage(Peer peer, Message message) {
-		HeightMessage heightMessage = (HeightMessage) message;
-
-		// Update all peers with same ID
-
-		List<Peer> connectedPeers = Network.getInstance().getHandshakedPeers();
-		for (Peer connectedPeer : connectedPeers) {
-			if (connectedPeer.getPeerId() == null || !Arrays.equals(connectedPeer.getPeerId(), peer.getPeerId()))
-				continue;
-
-			// Update peer chain tip data
-			PeerChainTipData newChainTipData = new PeerChainTipData(heightMessage.getHeight(), null, null, null);
-			connectedPeer.setChainTipData(newChainTipData);
-		}
-
-		// Potentially synchronize
-		requestSync = true;
-	}
-
-	private void onNetworkGetSignaturesMessage(Peer peer, Message message) {
-		GetSignaturesMessage getSignaturesMessage = (GetSignaturesMessage) message;
-		byte[] parentSignature = getSignaturesMessage.getParentSignature();
-
-		try (final Repository repository = RepositoryManager.getRepository()) {
-			List<byte[]> signatures = new ArrayList<>();
-
-			do {
-				BlockData blockData = repository.getBlockRepository().fromReference(parentSignature);
-
-				if (blockData == null)
-					break;
-
-				parentSignature = blockData.getSignature();
-				signatures.add(parentSignature);
-			} while (signatures.size() < Network.MAX_SIGNATURES_PER_REPLY);
-
-			Message signaturesMessage = new SignaturesMessage(signatures);
-			signaturesMessage.setId(message.getId());
-			if (!peer.sendMessage(signaturesMessage))
-				peer.disconnect("failed to send signatures");
-		} catch (DataException e) {
-			LOGGER.error(String.format("Repository issue while sending signatures after %s to peer %s", Base58.encode(parentSignature), peer), e);
-		}
-	}
-
 	private void onNetworkGetBlockMessage(Peer peer, Message message) {
 		GetBlockMessage getBlockMessage = (GetBlockMessage) message;
 		byte[] signature = getBlockMessage.getSignature();
@@ -953,40 +907,6 @@ public class Controller extends Thread {
 		}
 	}
 
-	private void onNetworkBlockMessage(Peer peer, Message message) {
-		// From a v1 peer, with no message ID, this is a broadcast of peer's latest block
-		// v2 peers announce new blocks using HEIGHT_V2
-
-		// Not version 1?
-		if (peer.getVersion() == null || peer.getVersion() > 1)
-			return;
-
-		// Message ID present?
-		// XXX Why is this test here? If BLOCK had an ID then surely it would be a response to GET_BLOCK
-		// and hence captured by Peer's reply queue?
-		if (message.hasId())
-			return;
-
-		BlockMessage blockMessage = (BlockMessage) message;
-		BlockData blockData = blockMessage.getBlockData();
-
-		// Update all peers with same ID
-
-		List<Peer> connectedPeers = Network.getInstance().getHandshakedPeers();
-		for (Peer connectedPeer : connectedPeers) {
-			// Skip connectedPeer if they have no ID or their ID doesn't match sender's ID
-			if (connectedPeer.getPeerId() == null || !Arrays.equals(connectedPeer.getPeerId(), peer.getPeerId()))
-				continue;
-
-			// Update peer chain tip data
-			PeerChainTipData newChainTipData = new PeerChainTipData(blockData.getHeight(), blockData.getSignature(), blockData.getTimestamp(), blockData.getMinterPublicKey());
-			connectedPeer.setChainTipData(newChainTipData);
-		}
-
-		// Potentially synchronize
-		requestSync = true;
-	}
-
 	private void onNetworkTransactionMessage(Peer peer, Message message) {
 		TransactionMessage transactionMessage = (TransactionMessage) message;
 		TransactionData transactionData = transactionMessage.getTransactionData();
@@ -1021,6 +941,9 @@ public class Controller extends Thread {
 		} catch (DataException e) {
 			LOGGER.error(String.format("Repository issue while processing transaction %s from peer %s", Base58.encode(transactionData.getSignature()), peer), e);
 		}
+
+		// Notify controller so it can notify other peers, etc.
+		Controller.getInstance().onNewTransaction(transactionData, peer);
 	}
 
 	private void onNetworkGetBlockSummariesMessage(Peer peer, Message message) {
@@ -1089,18 +1012,9 @@ public class Controller extends Thread {
 		if (!peer.isOutbound() && (peer.getChainTipData() == null || peer.getChainTipData().getLastHeight() == null))
 			peer.sendMessage(Network.getInstance().buildHeightMessage(peer, getChainTip()));
 
-		// Update all peers with same ID
-
-		List<Peer> connectedPeers = Network.getInstance().getHandshakedPeers();
-		for (Peer connectedPeer : connectedPeers) {
-			// Skip connectedPeer if they have no ID or their ID doesn't match sender's ID
-			if (connectedPeer.getPeerId() == null || !Arrays.equals(connectedPeer.getPeerId(), peer.getPeerId()))
-				continue;
-
-			// Update peer chain tip data
-			PeerChainTipData newChainTipData = new PeerChainTipData(heightV2Message.getHeight(), heightV2Message.getSignature(), heightV2Message.getTimestamp(), heightV2Message.getMinterPublicKey());
-			connectedPeer.setChainTipData(newChainTipData);
-		}
+		// Update peer chain tip data
+		PeerChainTipData newChainTipData = new PeerChainTipData(heightV2Message.getHeight(), heightV2Message.getSignature(), heightV2Message.getTimestamp(), heightV2Message.getMinterPublicKey());
+		peer.setChainTipData(newChainTipData);
 
 		// Potentially synchronize
 		requestSync = true;
@@ -1129,7 +1043,12 @@ 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))
@@ -1142,7 +1061,6 @@ public class Controller extends Thread {
 	private void onNetworkTransactionSignaturesMessage(Peer peer, Message message) {
 		TransactionSignaturesMessage transactionSignaturesMessage = (TransactionSignaturesMessage) message;
 		List<byte[]> signatures = transactionSignaturesMessage.getSignatures();
-		List<byte[]> newSignatures = new ArrayList<>();
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			for (byte[] signature : signatures) {
@@ -1158,62 +1076,14 @@ public class Controller extends Thread {
 
 				// Fetch actual transaction data from peer
 				Message getTransactionMessage = new GetTransactionMessage(signature);
-				Message responseMessage = peer.getResponse(getTransactionMessage);
-				if (!(responseMessage instanceof TransactionMessage)) {
-					// Maybe peer no longer has this transaction
-					LOGGER.trace(() -> String.format("Peer %s didn't send transaction %s", peer, Base58.encode(signature)));
-					continue;
-				}
-
-				// Check isInterrupted() here and exit fast
-				if (Thread.currentThread().isInterrupted())
+				if (!peer.sendMessage(getTransactionMessage)) {
+					peer.disconnect("failed to request transaction");
 					return;
-
-				TransactionMessage transactionMessage = (TransactionMessage) responseMessage;
-				TransactionData transactionData = transactionMessage.getTransactionData();
-				Transaction transaction = Transaction.fromData(repository, transactionData);
-
-				// Check signature
-				if (!transaction.isSignatureValid()) {
-					LOGGER.trace(() -> String.format("Ignoring %s transaction %s with invalid signature from peer %s", transactionData.getType().name(), Base58.encode(transactionData.getSignature()), peer));
-					continue;
 				}
-
-				ValidationResult validationResult = transaction.importAsUnconfirmed();
-
-				if (validationResult == ValidationResult.TRANSACTION_ALREADY_EXISTS) {
-					LOGGER.trace(() -> String.format("Ignoring existing transaction %s from peer %s", Base58.encode(transactionData.getSignature()), peer));
-					continue;
-				}
-
-				if (validationResult == ValidationResult.NO_BLOCKCHAIN_LOCK) {
-					LOGGER.trace(() -> String.format("Couldn't lock blockchain to import unconfirmed transaction %s from peer %s", Base58.encode(transactionData.getSignature()), peer));
-					// Some other thread (e.g. Synchronizer) might have blockchain lock for a while so might as well give up for now
-					break;
-				}
-
-				if (validationResult != ValidationResult.OK) {
-					LOGGER.trace(() -> String.format("Ignoring invalid (%s) %s transaction %s from peer %s", validationResult.name(), transactionData.getType().name(), Base58.encode(transactionData.getSignature()), peer));
-					continue;
-				}
-
-				LOGGER.debug(() -> String.format("Imported %s transaction %s from peer %s", transactionData.getType().name(), Base58.encode(transactionData.getSignature()), peer));
-
-				// We could collate signatures that are new to us and broadcast them to our peers too
-				newSignatures.add(signature);
 			}
 		} catch (DataException e) {
 			LOGGER.error(String.format("Repository issue while processing unconfirmed transactions from peer %s", peer), e);
-		} catch (InterruptedException e) {
-			// Shutdown
-			return;
 		}
-
-		if (newSignatures.isEmpty())
-			return;
-
-		// Broadcast signatures that are new to us
-		Network.getInstance().broadcast(broadcastPeer -> broadcastPeer == peer ? null : new TransactionSignaturesMessage(newSignatures));
 	}
 
 	private void onNetworkGetArbitraryDataMessage(Peer peer, Message message) {
@@ -1603,7 +1473,7 @@ public class Controller extends Thread {
 		getArbitraryDataMessage.setId(id);
 
 		// Broadcast request
-		Network.getInstance().broadcast(peer -> peer.getVersion() < 2 ? null : getArbitraryDataMessage);
+		Network.getInstance().broadcast(peer -> getArbitraryDataMessage);
 
 		// Poll to see if data has arrived
 		final long singleWait = 100;
@@ -1635,7 +1505,7 @@ public class Controller extends Thread {
 		if (minLatestBlockTimestamp == null)
 			return null;
 
-		List<Peer> peers = Network.getInstance().getUniqueHandshakedPeers();
+		List<Peer> peers = Network.getInstance().getHandshakedPeers();
 
 		// Filter out unsuitable peers
 		Iterator<Peer> iterator = peers.iterator();
@@ -1681,7 +1551,7 @@ public class Controller extends Thread {
 		if (latestBlockData == null || latestBlockData.getTimestamp() < minLatestBlockTimestamp)
 			return false;
 
-		List<Peer> peers = Network.getInstance().getUniqueHandshakedPeers();
+		List<Peer> peers = Network.getInstance().getHandshakedPeers();
 		if (peers == null)
 			return false;
 

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

@@ -0,0 +1,56 @@
+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;
+
+public class StatusNotifier {
+
+	private static StatusNotifier instance;
+
+	@FunctionalInterface
+	public interface Listener {
+		void notify(long timestamp);
+	}
+
+	private Map<Session, Listener> listenersBySession = new HashMap<>();
+
+	private StatusNotifier() {
+	}
+
+	public static synchronized StatusNotifier getInstance() {
+		if (instance == null)
+			instance = new StatusNotifier();
+
+		return instance;
+	}
+
+	public void register(Session session, Listener listener) {
+		synchronized (this.listenersBySession) {
+			this.listenersBySession.put(session, listener);
+		}
+	}
+
+	public void deregister(Session session) {
+		synchronized (this.listenersBySession) {
+			this.listenersBySession.remove(session);
+		}
+	}
+
+	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

@@ -22,7 +22,6 @@ import org.qortal.network.message.BlockMessage;
 import org.qortal.network.message.BlockSummariesMessage;
 import org.qortal.network.message.GetBlockMessage;
 import org.qortal.network.message.GetBlockSummariesMessage;
-import org.qortal.network.message.GetSignaturesMessage;
 import org.qortal.network.message.GetSignaturesV2Message;
 import org.qortal.network.message.Message;
 import org.qortal.network.message.SignaturesMessage;
@@ -372,12 +371,7 @@ public class Synchronizer {
 				return SynchronizationResult.TOO_DIVERGENT;
 			}
 
-			if (peer.getVersion() >= 2) {
-				step <<= 1;
-			} else {
-				// Old v1 peers are hard-coded to return 500 signatures so we might as well go backward by 500 too
-				step = 500;
-			}
+			step <<= 1;
 			step = Math.min(step, MAXIMUM_BLOCK_STEP);
 
 			testHeight = Math.max(testHeight - step, 1);
@@ -415,8 +409,7 @@ public class Synchronizer {
 	}
 
 	private List<byte[]> getBlockSignatures(Peer peer, byte[] parentSignature, int numberRequested) throws InterruptedException {
-		// numberRequested is v2+ feature
-		Message getSignaturesMessage = peer.getVersion() >= 2 ? new GetSignaturesV2Message(parentSignature, numberRequested) : new GetSignaturesMessage(parentSignature);
+		Message getSignaturesMessage = new GetSignaturesV2Message(parentSignature, numberRequested);
 
 		Message message = peer.getResponse(getSignaturesMessage);
 		if (message == null || message.getType() != MessageType.SIGNATURES)

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

@@ -1,199 +1,72 @@
 package org.qortal.crosschain;
 
-import java.io.ByteArrayInputStream;
-import java.io.DataOutputStream;
-import java.io.File;
-import java.io.FileInputStream;
-import java.io.FileNotFoundException;
-import java.io.FileOutputStream;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStreamWriter;
-import java.io.PrintWriter;
-import java.nio.ByteBuffer;
-import java.nio.charset.StandardCharsets;
-import java.security.DigestOutputStream;
-import java.security.MessageDigest;
-import java.util.Date;
+import java.util.ArrayList;
 import java.util.List;
-import java.util.concurrent.ExecutionException;
-import java.util.concurrent.TimeoutException;
+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.BlockChain;
-import org.bitcoinj.core.CheckpointManager;
 import org.bitcoinj.core.Coin;
-import org.bitcoinj.core.ECKey;
 import org.bitcoinj.core.NetworkParameters;
-import org.bitcoinj.core.PeerGroup;
-import org.bitcoinj.core.Sha256Hash;
-import org.bitcoinj.core.StoredBlock;
 import org.bitcoinj.core.Transaction;
 import org.bitcoinj.core.TransactionOutput;
-import org.bitcoinj.core.VerificationException;
-import org.bitcoinj.core.listeners.NewBestBlockListener;
-import org.bitcoinj.net.discovery.DnsDiscovery;
 import org.bitcoinj.params.MainNetParams;
+import org.bitcoinj.params.RegTestParams;
 import org.bitcoinj.params.TestNet3Params;
-import org.bitcoinj.script.Script;
-import org.bitcoinj.store.BlockStore;
-import org.bitcoinj.store.BlockStoreException;
-import org.bitcoinj.store.SPVBlockStore;
-import org.bitcoinj.utils.Threading;
-import org.bitcoinj.wallet.KeyChainGroup;
-import org.bitcoinj.wallet.Wallet;
-import org.bitcoinj.wallet.listeners.WalletCoinsReceivedEventListener;
+import org.bitcoinj.script.ScriptBuilder;
+import org.bitcoinj.utils.MonetaryFormat;
 import org.qortal.settings.Settings;
+import org.qortal.utils.BitTwiddling;
+import org.qortal.utils.Pair;
 
 public class BTC {
 
-	private static class RollbackBlockChain extends BlockChain {
+	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;
 
-		public RollbackBlockChain(NetworkParameters params, BlockStore blockStore) throws BlockStoreException {
-			super(params, blockStore);
-		}
+	protected static final Logger LOGGER = LogManager.getLogger(BTC.class);
 
-		@Override
-		public void setChainHead(StoredBlock chainHead) throws BlockStoreException {
-			super.setChainHead(chainHead);
-		}
+	private static final int TIMESTAMP_OFFSET = 4 + 32 + 32;
 
-	}
-
-	private static class UpdateableCheckpointManager extends CheckpointManager implements NewBestBlockListener {
-
-		private static final int checkpointInterval = 500;
-
-		private static final String minimalTestNet3TextFile = "TXT CHECKPOINTS 1\n0\n1\nAAAAAAAAB+EH4QfhAAAH4AEAAAApmwX6UCEnJcYIKTa7HO3pFkqqNhAzJVBMdEuGAAAAAPSAvVCBUypCbBW/OqU0oIF7ISF84h2spOqHrFCWN9Zw6r6/T///AB0E5oOO\n";
-		private static final String minimalMainNetTextFile = "TXT CHECKPOINTS 1\n0\n1\nAAAAAAAAB+EH4QfhAAAH4AEAAABjl7tqvU/FIcDT9gcbVlA4nwtFUbxAtOawZzBpAAAAAKzkcK7NqciBjI/ldojNKncrWleVSgDfBCCn3VRrbSxXaw5/Sf//AB0z8Bkv\n";
-
-		public UpdateableCheckpointManager(NetworkParameters params) throws IOException {
-			super(params, getMinimalTextFileStream(params));
-		}
-
-		public UpdateableCheckpointManager(NetworkParameters params, InputStream inputStream) throws IOException {
-			super(params, inputStream);
-		}
-
-		private static ByteArrayInputStream getMinimalTextFileStream(NetworkParameters params) {
-			if (params == MainNetParams.get())
-				return new ByteArrayInputStream(minimalMainNetTextFile.getBytes());
-
-			if (params == TestNet3Params.get())
-				return new ByteArrayInputStream(minimalTestNet3TextFile.getBytes());
-
-			throw new RuntimeException("Failed to construct empty UpdateableCheckpointManageer");
-		}
-
-		@Override
-		public void notifyNewBestBlock(StoredBlock block) throws VerificationException {
-			int height = block.getHeight();
-
-			if (height % checkpointInterval == 0)
-				checkpoints.put(block.getHeader().getTimeSeconds(), block);
-		}
-
-		public void saveAsText(File textFile) throws FileNotFoundException {
-			try (PrintWriter writer = new PrintWriter(new OutputStreamWriter(new FileOutputStream(textFile), StandardCharsets.US_ASCII))) {
-				writer.println("TXT CHECKPOINTS 1");
-				writer.println("0"); // Number of signatures to read. Do this later.
-				writer.println(checkpoints.size());
-				ByteBuffer buffer = ByteBuffer.allocate(StoredBlock.COMPACT_SERIALIZED_SIZE);
-				for (StoredBlock block : checkpoints.values()) {
-					block.serializeCompact(buffer);
-					writer.println(CheckpointManager.BASE64.encode(buffer.array()));
-					buffer.position(0);
-				}
+	public enum BitcoinNet {
+		MAIN {
+			@Override
+			public NetworkParameters getParams() {
+				return MainNetParams.get();
 			}
-		}
-
-		@SuppressWarnings("unused")
-		public void saveAsBinary(File file) throws IOException {
-			try (final FileOutputStream fileOutputStream = new FileOutputStream(file, false)) {
-				MessageDigest digest = Sha256Hash.newDigest();
-
-				try (final DigestOutputStream digestOutputStream = new DigestOutputStream(fileOutputStream, digest)) {
-					digestOutputStream.on(false);
-
-					try (final DataOutputStream dataOutputStream = new DataOutputStream(digestOutputStream)) {
-						dataOutputStream.writeBytes("CHECKPOINTS 1");
-						dataOutputStream.writeInt(0); // Number of signatures to read. Do this later.
-						digestOutputStream.on(true);
-						dataOutputStream.writeInt(checkpoints.size());
-						ByteBuffer buffer = ByteBuffer.allocate(StoredBlock.COMPACT_SERIALIZED_SIZE);
-						for (StoredBlock block : checkpoints.values()) {
-							block.serializeCompact(buffer);
-							dataOutputStream.write(buffer.array());
-							buffer.position(0);
-						}
-					}
-				}
+		},
+		TEST3 {
+			@Override
+			public NetworkParameters getParams() {
+				return TestNet3Params.get();
 			}
-		}
+		},
+		REGTEST {
+			@Override
+			public NetworkParameters getParams() {
+				return RegTestParams.get();
+			}
+		};
 
+		public abstract NetworkParameters getParams();
 	}
 
 	private static BTC instance;
-	private static final Object instanceLock = new Object();
+	private final NetworkParameters params;
+	private final ElectrumX electrumX;
 
-	private static File directory;
-	private static String chainFileName;
-	private static String checkpointsFileName;
-
-	private static NetworkParameters params;
-	private static PeerGroup peerGroup;
-	private static BlockStore blockStore;
-	private static RollbackBlockChain chain;
-	private static UpdateableCheckpointManager manager;
+	// Constructors and instance
 
 	private BTC() {
-		// Start wallet
-		if (Settings.getInstance().useBitcoinTestNet()) {
-			params = TestNet3Params.get();
-			chainFileName = "bitcoinj-testnet.spvchain";
-			checkpointsFileName = "checkpoints-testnet.txt";
-		} else {
-			params = MainNetParams.get();
-			chainFileName = "bitcoinj.spvchain";
-			checkpointsFileName = "checkpoints.txt";
-		}
+		BitcoinNet bitcoinNet = Settings.getInstance().getBitcoinNet();
+		this.params = bitcoinNet.getParams();
 
-		directory = new File("Qortal-BTC");
-		if (!directory.exists())
-			directory.mkdirs();
+		LOGGER.info(() -> String.format("Starting Bitcoin support using %s", bitcoinNet.name()));
 
-		File chainFile = new File(directory, chainFileName);
-
-		try {
-			blockStore = new SPVBlockStore(params, chainFile);
-		} catch (BlockStoreException e) {
-			throw new RuntimeException("Failed to open/create BTC SPVBlockStore", e);
-		}
-
-		File checkpointsFile = new File(directory, checkpointsFileName);
-		try (InputStream checkpointsStream = new FileInputStream(checkpointsFile)) {
-			manager = new UpdateableCheckpointManager(params, checkpointsStream);
-		} catch (FileNotFoundException e) {
-			// Construct with no checkpoints then
-			try {
-				manager = new UpdateableCheckpointManager(params);
-			} catch (IOException e2) {
-				throw new RuntimeException("Failed to create new BTC checkpoints", e2);
-			}
-		} catch (IOException e) {
-			throw new RuntimeException("Failed to load BTC checkpoints", e);
-		}
-
-		try {
-			chain = new RollbackBlockChain(params, blockStore);
-		} catch (BlockStoreException e) {
-			throw new RuntimeException("Failed to construct BTC blockchain", e);
-		}
-
-		peerGroup = new PeerGroup(params, chain);
-		peerGroup.setUserAgent("qortal", "1.0");
-		peerGroup.addPeerDiscovery(new DnsDiscovery(params));
-		peerGroup.start();
+		this.electrumX = ElectrumX.getInstance(bitcoinNet.name());
 	}
 
 	public static synchronized BTC getInstance() {
@@ -203,109 +76,84 @@ public class BTC {
 		return instance;
 	}
 
-	public void shutdown() {
-		synchronized (instanceLock) {
-			if (instance == null)
-				return;
+	// Getters & setters
 
-			instance = null;
-		}
-
-		peerGroup.stop();
-
-		try {
-			blockStore.close();
-		} catch (BlockStoreException e) {
-			// What can we do?
-		}
+	public NetworkParameters getNetworkParameters() {
+		return this.params;
 	}
 
-	protected Wallet createEmptyWallet() {
-		ECKey dummyKey = new ECKey();
-
-		KeyChainGroup keyChainGroup = KeyChainGroup.createBasic(params);
-		keyChainGroup.importKeys(dummyKey);
-
-		Wallet wallet = new Wallet(params, keyChainGroup);
-
-		wallet.removeKey(dummyKey);
-
-		return wallet;
+	public static synchronized void resetForTesting() {
+		instance = null;
 	}
 
-	public void watch(String base58Address, long startTime) throws InterruptedException, ExecutionException, TimeoutException, BlockStoreException {
-		Wallet wallet = createEmptyWallet();
+	// Actual useful methods for use by other classes
 
-		WalletCoinsReceivedEventListener coinsReceivedListener = new WalletCoinsReceivedEventListener() {
-			@Override
-			public void onCoinsReceived(Wallet wallet, Transaction tx, Coin prevBalance, Coin newBalance) {
-				System.out.println("Coins received via transaction " + tx.getTxId().toString());
-			}
-		};
-		wallet.addCoinsReceivedEventListener(coinsReceivedListener);
+	/** Returns median timestamp from latest 11 blocks, in seconds. */
+	public Integer getMedianBlockTime() {
+		Integer height = this.electrumX.getCurrentHeight();
+		if (height == null)
+			return null;
 
-		Address address = Address.fromString(params, base58Address);
-		wallet.addWatchedAddress(address, startTime);
+		// Grab latest 11 blocks
+		List<byte[]> blockHeaders = this.electrumX.getBlockHeaders(height - 11, 11);
+		if (blockHeaders == null || blockHeaders.size() < 11)
+			return null;
 
-		StoredBlock checkpoint = manager.getCheckpointBefore(startTime);
-		blockStore.put(checkpoint);
-		blockStore.setChainHead(checkpoint);
-		chain.setChainHead(checkpoint);
+		List<Integer> blockTimestamps = blockHeaders.stream().map(blockHeader -> BitTwiddling.fromLEBytes(blockHeader, TIMESTAMP_OFFSET)).collect(Collectors.toList());
 
-		chain.addWallet(wallet);
-		peerGroup.addWallet(wallet);
-		peerGroup.setFastCatchupTimeSecs(startTime);
+		// Descending, but order shouldn't matter as we're picking median...
+		blockTimestamps.sort((a, b) -> Integer.compare(b, a));
 
-		peerGroup.addBlocksDownloadedEventListener((peer, block, filteredBlock, blocksLeft) -> {
-			if (blocksLeft % 1000 == 0)
-				System.out.println("Blocks left: " + blocksLeft);
-		});
-
-		System.out.println("Starting download...");
-		peerGroup.downloadBlockChain();
-
-		List<TransactionOutput> outputs = wallet.getWatchedOutputs(true);
-
-		peerGroup.removeWallet(wallet);
-		chain.removeWallet(wallet);
-
-		for (TransactionOutput output : outputs)
-			System.out.println(output.toString());
+		return blockTimestamps.get(5);
 	}
 
-	public void watch(Script script) {
-		// wallet.addWatchedScripts(scripts);
+	public Coin getBalance(String base58Address) {
+		Long balance = this.electrumX.getBalance(addressToScript(base58Address));
+		if (balance == null)
+			return null;
+
+		return Coin.valueOf(balance);
 	}
 
-	public void updateCheckpoints() {
-		final long now = new Date().getTime() / 1000 - 86400;
+	public List<TransactionOutput> getUnspentOutputs(String base58Address) {
+		List<Pair<byte[], Integer>> unspentOutputs = this.electrumX.getUnspentOutputs(addressToScript(base58Address));
+		if (unspentOutputs == null)
+			return null;
 
-		try {
-			StoredBlock checkpoint = manager.getCheckpointBefore(now);
-			blockStore.put(checkpoint);
-			blockStore.setChainHead(checkpoint);
-			chain.setChainHead(checkpoint);
-		} catch (BlockStoreException e) {
-			throw new RuntimeException("Failed to update BTC checkpoints", e);
+		List<TransactionOutput> unspentTransactionOutputs = new ArrayList<>();
+		for (Pair<byte[], Integer> unspentOutput : unspentOutputs) {
+			List<TransactionOutput> transactionOutputs = getOutputs(unspentOutput.getA());
+			if (transactionOutputs == null)
+				return null;
+
+			unspentTransactionOutputs.add(transactionOutputs.get(unspentOutput.getB()));
 		}
 
-		peerGroup.setFastCatchupTimeSecs(now);
+		return unspentTransactionOutputs;
+	}
 
-		chain.addNewBestBlockListener(Threading.SAME_THREAD, manager);
+	public List<TransactionOutput> getOutputs(byte[] txHash) {
+		byte[] rawTransactionBytes = this.electrumX.getRawTransaction(txHash);
+		if (rawTransactionBytes == null)
+			return null;
 
-		peerGroup.addBlocksDownloadedEventListener((peer, block, filteredBlock, blocksLeft) -> {
-			if (blocksLeft % 1000 == 0)
-				System.out.println("Blocks left: " + blocksLeft);
-		});
+		Transaction transaction = new Transaction(this.params, rawTransactionBytes);
+		return transaction.getOutputs();
+	}
 
-		System.out.println("Starting download...");
-		peerGroup.downloadBlockChain();
+	public List<byte[]> getAddressTransactions(String base58Address) {
+		return this.electrumX.getAddressTransactions(addressToScript(base58Address));
+	}
 
-		try {
-			manager.saveAsText(new File(directory, checkpointsFileName));
-		} catch (FileNotFoundException e) {
-			throw new RuntimeException("Failed to save updated BTC checkpoints", e);
-		}
+	public boolean broadcastTransaction(Transaction transaction) {
+		return this.electrumX.broadcastTransaction(transaction.bitcoinSerialize());
+	}
+
+	// Utility methods for us
+
+	private byte[] addressToScript(String base58Address) {
+		Address address = Address.fromString(this.params, base58Address);
+		return ScriptBuilder.createOutputScript(address).getProgram();
 	}
 
 }

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

@@ -0,0 +1,669 @@
+package org.qortal.crosschain;
+
+import static org.ciyam.at.OpCode.calcOffset;
+
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+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.ciyam.at.API;
+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.qortal.account.Account;
+import org.qortal.asset.Asset;
+import org.qortal.at.QortalAtLoggerFactory;
+import org.qortal.block.BlockChain;
+import org.qortal.block.BlockChain.CiyamAtSettings;
+import org.qortal.crypto.Crypto;
+import org.qortal.data.at.ATData;
+import org.qortal.data.at.ATStateData;
+import org.qortal.data.block.BlockData;
+import org.qortal.data.crosschain.CrossChainTradeData;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.utils.Base58;
+import org.qortal.utils.BitTwiddling;
+
+import com.google.common.hash.HashCode;
+import com.google.common.primitives.Bytes;
+
+/*
+ * Bob generates Bitcoin private key
+ * 		private key required to sign P2SH redeem tx
+ * 		private key can be used to create 'secret' (e.g. double-SHA256)
+ * 		encrypted private key could be stored in Qortal AT for access by Bob from any node
+ * Bob creates Qortal AT
+ * Alice finds Qortal AT and wants to trade
+ * 		Alice generates Bitcoin private key
+ * 		Alice will need to send Bob her Qortal address and Bitcoin refund address
+ * Bob sends Alice's Qortal address to Qortal AT
+ * Qortal AT sends initial QORT payment to Alice (so she has QORT to send message to AT and claim funds)
+ * Alice receives funds and checks Qortal AT to confirm it's locked to her
+ * Alice creates/funds Bitcoin P2SH
+ * 		Alice requires: Bob's redeem Bitcoin address, Alice's refund Bitcoin address, derived locktime
+ * Bob checks P2SH is funded
+ * 		Bob requires: Bob's redeem Bitcoin address, Alice's refund Bitcoin address, derived locktime
+ * Bob uses secret to redeem P2SH
+ * 		Qortal core/UI will need to create, and sign, this transaction
+ * Alice scans P2SH redeem tx and uses secret to redeem Qortal AT
+ */
+
+public class BTCACCT {
+
+	public static final int SECRET_LENGTH = 32;
+	public static final int MIN_LOCKTIME = 1500000000;
+	public static final byte[] CODE_BYTES_HASH = HashCode.fromString("edcdb1feb36e079c5f956faff2f24219b12e5fbaaa05654335e615e33218282f").asBytes(); // SHA256 of AT code bytes
+
+	/*
+	 * 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 BTCACCT} 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
+	 * @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) {
+		NetworkParameters params = BTC.getInstance().getNetworkParameters();
+
+		Transaction transaction = new Transaction(params);
+		transaction.setVersion(2);
+
+		// Output is back to P2SH funder
+		transaction.addOutput(amount, ScriptBuilder.createP2PKHOutputScript(spendKey.getPubKeyHash()));
+
+		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, so no lockTime and no RBF
+			else
+				input.setSequenceNumber(BTC.NO_LOCKTIME_NO_RBF_SEQUENCE); // Use max-value - 1, so lockTime can be used but not 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();
+		};
+
+		return buildP2shTransaction(refundAmount, refundKey, fundingOutputs, redeemScriptBytes, lockTime, refundSigScriptBuilder);
+	}
+
+	/**
+	 * 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
+	 * @return Signed Bitcoin transaction for redeeming P2SH
+	 */
+	public static Transaction buildRedeemTransaction(Coin redeemAmount, ECKey redeemKey, List<TransactionOutput> fundingOutputs, byte[] redeemScriptBytes, byte[] secret) {
+		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);
+	}
+
+	/**
+	 * Returns Qortal AT creation bytes for cross-chain trading AT.
+	 * <p>
+	 * <tt>tradeTimeout</tt> (minutes) is the time window for the recipient to send the
+	 * 32-byte secret to the AT, before the AT automatically refunds the AT's creator.
+	 * 
+	 * @param qortalCreator Qortal address for AT creator, also used for refunds
+	 * @param secretHash 20-byte HASH160 of 32-byte secret
+	 * @param tradeTimeout how many minutes, from start of 'trade mode' until AT auto-refunds AT creator
+	 * @param initialPayout how much QORT to pay trade partner upon switch to 'trade mode'
+	 * @param redeemPayout how much QORT to pay trade partner if they send correct 32-byte secret to AT
+	 * @param bitcoinAmount how much BTC the AT creator is expecting to trade
+	 * @return
+	 */
+	public static byte[] buildQortalAT(String qortalCreator, byte[] secretHash, int tradeTimeout, long initialPayout, long redeemPayout, long bitcoinAmount) {
+		// Labels for data segment addresses
+		int addrCounter = 0;
+
+		// Constants (with corresponding dataByteBuffer.put*() calls below)
+
+		final int addrQortalCreator1 = addrCounter++;
+		final int addrQortalCreator2 = addrCounter++;
+		final int addrQortalCreator3 = addrCounter++;
+		final int addrQortalCreator4 = addrCounter++;
+
+		final int addrSecretHash = addrCounter;
+		addrCounter += 4;
+
+		final int addrTradeTimeout = addrCounter++;
+		final int addrInitialPayoutAmount = addrCounter++;
+		final int addrRedeemPayoutAmount = addrCounter++;
+		final int addrBitcoinAmount = addrCounter++;
+
+		final int addrMessageTxType = addrCounter++;
+
+		final int addrSecretHashPointer = addrCounter++;
+		final int addrQortalRecipientPointer = addrCounter++;
+		final int addrMessageSenderPointer = addrCounter++;
+
+		final int addrMessageDataPointer = addrCounter++;
+		final int addrMessageDataLength = addrCounter++;
+
+		final int addrEndOfConstants = addrCounter;
+
+		// Variables
+
+		final int addrQortalRecipient1 = addrCounter++;
+		final int addrQortalRecipient2 = addrCounter++;
+		final int addrQortalRecipient3 = addrCounter++;
+		final int addrQortalRecipient4 = addrCounter++;
+
+		final int addrTradeRefundTimestamp = addrCounter++;
+		final int addrLastTxTimestamp = addrCounter++;
+		final int addrBlockTimestamp = addrCounter++;
+		final int addrTxType = addrCounter++;
+		final int addrResult = addrCounter++;
+
+		final int addrMessageSender1 = addrCounter++;
+		final int addrMessageSender2 = addrCounter++;
+		final int addrMessageSender3 = addrCounter++;
+		final int addrMessageSender4 = addrCounter++;
+
+		final int addrMessageData = addrCounter;
+		addrCounter += 4;
+
+		// Data segment
+		ByteBuffer dataByteBuffer = ByteBuffer.allocate(addrCounter * MachineState.VALUE_SIZE);
+
+		// AT creator's Qortal address, decoded from Base58
+		assert dataByteBuffer.position() == addrQortalCreator1 * MachineState.VALUE_SIZE : "addrQortalCreator1 incorrect";
+		byte[] qortalCreatorBytes = Base58.decode(qortalCreator);
+		dataByteBuffer.put(Bytes.ensureCapacity(qortalCreatorBytes, 32, 0));
+
+		// Hash of secret
+		assert dataByteBuffer.position() == addrSecretHash * MachineState.VALUE_SIZE : "addrSecretHash incorrect";
+		dataByteBuffer.put(Bytes.ensureCapacity(secretHash, 32, 0));
+
+		// Trade timeout in minutes
+		assert dataByteBuffer.position() == addrTradeTimeout * MachineState.VALUE_SIZE : "addrTradeTimeout incorrect";
+		dataByteBuffer.putLong(tradeTimeout);
+
+		// Initial payout amount
+		assert dataByteBuffer.position() == addrInitialPayoutAmount * MachineState.VALUE_SIZE : "addrInitialPayoutAmount incorrect";
+		dataByteBuffer.putLong(initialPayout);
+
+		// Redeem payout amount
+		assert dataByteBuffer.position() == addrRedeemPayoutAmount * MachineState.VALUE_SIZE : "addrRedeemPayoutAmount incorrect";
+		dataByteBuffer.putLong(redeemPayout);
+
+		// Expected Bitcoin amount
+		assert dataByteBuffer.position() == addrBitcoinAmount * MachineState.VALUE_SIZE : "addrBitcoinAmount incorrect";
+		dataByteBuffer.putLong(bitcoinAmount);
+
+		// We're only interested in MESSAGE transactions
+		assert dataByteBuffer.position() == addrMessageTxType * MachineState.VALUE_SIZE : "addrMessageTxType incorrect";
+		dataByteBuffer.putLong(API.ATTransactionType.MESSAGE.value);
+
+		// Index into data segment of hash, used by GET_B_IND
+		assert dataByteBuffer.position() == addrSecretHashPointer * MachineState.VALUE_SIZE : "addrSecretHashPointer incorrect";
+		dataByteBuffer.putLong(addrSecretHash);
+
+		// Index into data segment of recipient address, used by SET_B_IND
+		assert dataByteBuffer.position() == addrQortalRecipientPointer * MachineState.VALUE_SIZE : "addrQortalRecipientPointer incorrect";
+		dataByteBuffer.putLong(addrQortalRecipient1);
+
+		// Index into data segment of (temporary) transaction's sender's address, used by GET_B_IND
+		assert dataByteBuffer.position() == addrMessageSenderPointer * MachineState.VALUE_SIZE : "addrMessageSenderPointer incorrect";
+		dataByteBuffer.putLong(addrMessageSender1);
+
+		// Source location and length for hashing any passed secret
+		assert dataByteBuffer.position() == addrMessageDataPointer * MachineState.VALUE_SIZE : "addrMessageDataPointer incorrect";
+		dataByteBuffer.putLong(addrMessageData);
+		assert dataByteBuffer.position() == addrMessageDataLength * MachineState.VALUE_SIZE : "addrMessageDataLength incorrect";
+		dataByteBuffer.putLong(32L);
+
+		assert dataByteBuffer.position() == addrEndOfConstants * MachineState.VALUE_SIZE : "dataByteBuffer position not at end of constants";
+
+		// Code labels
+		Integer labelRefund = null;
+
+		Integer labelOfferTxLoop = null;
+		Integer labelCheckOfferTx = null;
+
+		Integer labelTradeMode = null;
+		Integer labelTradeTxLoop = null;
+		Integer labelCheckTradeTx = 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 from AT owner containing trade partner details, or AT owner's address to cancel offer */
+
+				/* Transaction processing loop */
+				labelOfferTxLoop = codeByteBuffer.position();
+
+				// Find next transaction to this AT since the last one (if any)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PUT_TX_AFTER_TIMESTAMP_INTO_A, 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, calcOffset(codeByteBuffer, labelCheckOfferTx)));
+				// Stop and wait for next block
+				codeByteBuffer.put(OpCode.STP_IMD.compile());
+
+				/* Check transaction */
+				labelCheckOfferTx = 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));
+				// Extract transaction type (message/payment) from transaction and save type in addrTxType
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TYPE_FROM_TX_IN_A, addrTxType));
+				// If transaction type is not MESSAGE type then go look for another transaction
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrTxType, addrMessageTxType, calcOffset(codeByteBuffer, labelOfferTxLoop)));
+
+				/* Check transaction's sender */
+
+				// Extract sender address from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_ADDRESS_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrMessageSender1 (as pointed to by addrMessageSenderPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrMessageSenderPointer));
+				// Compare each part of transaction's sender's address with expected address. If they don't match, look for another transaction.
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender1, addrQortalCreator1, calcOffset(codeByteBuffer, labelOfferTxLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender2, addrQortalCreator2, calcOffset(codeByteBuffer, labelOfferTxLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender3, addrQortalCreator3, calcOffset(codeByteBuffer, labelOfferTxLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender4, addrQortalCreator4, calcOffset(codeByteBuffer, labelOfferTxLoop)));
+
+				/* Extract trade partner info from message */
+
+				// Extract message from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_MESSAGE_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrQortalRecipient1 (as pointed to by addrQortalRecipientPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrQortalRecipientPointer));
+				// Compare each of recipient address with creator's address (for offer-cancel scenario). If they don't match, assume recipient is trade partner.
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrQortalRecipient1, addrQortalCreator1, calcOffset(codeByteBuffer, labelTradeMode)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrQortalRecipient2, addrQortalCreator2, calcOffset(codeByteBuffer, labelTradeMode)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrQortalRecipient3, addrQortalCreator3, calcOffset(codeByteBuffer, labelTradeMode)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrQortalRecipient4, addrQortalCreator4, calcOffset(codeByteBuffer, labelTradeMode)));
+				// Recipient address is AT creator's address, so cancel offer and finish.
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelRefund == null ? 0 : labelRefund));
+
+				/* Switch to 'trade mode' */
+				labelTradeMode = codeByteBuffer.position();
+
+				// Send initial payment to recipient so they have enough funds to message AT if all goes well
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PAY_TO_ADDRESS_IN_B, addrInitialPayoutAmount));
+
+				// Calculate trade timeout refund 'timestamp' by adding addrTradeTimeout minutes to above message's 'timestamp', then save into addrTradeRefundTimestamp
+				codeByteBuffer.put(OpCode.EXT_FUN_RET_DAT_2.compile(FunctionCode.ADD_MINUTES_TO_TIMESTAMP, addrTradeRefundTimestamp, addrLastTxTimestamp, addrTradeTimeout));
+
+				// Set restart position to after this opcode
+				codeByteBuffer.put(OpCode.SET_PCS.compile());
+
+				/* Loop, waiting for trade timeout or message from Qortal trade recipient containing secret */
+
+				// Fetch current block 'timestamp'
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_BLOCK_TIMESTAMP, addrBlockTimestamp));
+				// If we're not past refund 'timestamp' then look for next transaction
+				codeByteBuffer.put(OpCode.BLT_DAT.compile(addrBlockTimestamp, addrTradeRefundTimestamp, calcOffset(codeByteBuffer, labelTradeTxLoop)));
+				// We're past refund 'timestamp' so go refund everything back to AT creator
+				codeByteBuffer.put(OpCode.JMP_ADR.compile(labelRefund == null ? 0 : labelRefund));
+
+				/* Transaction processing loop */
+				labelTradeTxLoop = codeByteBuffer.position();
+
+				// Find next transaction to this AT since the last one (if any)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PUT_TX_AFTER_TIMESTAMP_INTO_A, 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, calcOffset(codeByteBuffer, labelCheckTradeTx)));
+				// Stop and wait for next block
+				codeByteBuffer.put(OpCode.STP_IMD.compile());
+
+				/* Check transaction */
+				labelCheckTradeTx = 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));
+				// Extract transaction type (message/payment) from transaction and save type in addrTxType
+				codeByteBuffer.put(OpCode.EXT_FUN_RET.compile(FunctionCode.GET_TYPE_FROM_TX_IN_A, addrTxType));
+				// If transaction type is not MESSAGE type then go look for another transaction
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrTxType, addrMessageTxType, calcOffset(codeByteBuffer, labelTradeTxLoop)));
+
+				/* Check transaction's sender */
+
+				// Extract sender address from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_ADDRESS_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrMessageSender1 (as pointed to by addrMessageSenderPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrMessageSenderPointer));
+				// Compare each part of transaction's sender's address with expected address. If they don't match, look for another transaction.
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender1, addrQortalRecipient1, calcOffset(codeByteBuffer, labelTradeTxLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender2, addrQortalRecipient2, calcOffset(codeByteBuffer, labelTradeTxLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender3, addrQortalRecipient3, calcOffset(codeByteBuffer, labelTradeTxLoop)));
+				codeByteBuffer.put(OpCode.BNE_DAT.compile(addrMessageSender4, addrQortalRecipient4, calcOffset(codeByteBuffer, labelTradeTxLoop)));
+
+				/* Check 'secret' in transaction's message */
+
+				// Extract message from transaction into B register
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_MESSAGE_FROM_TX_IN_A_INTO_B));
+				// Save B register into data segment starting at addrMessageData (as pointed to by addrMessageDataPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.GET_B_IND, addrMessageDataPointer));
+				// Load B register with expected hash result (as pointed to by addrSecretHashPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.SET_B_IND, addrSecretHashPointer));
+				// Perform HASH160 using source data at addrMessageData. (Location and length specified via addrMessageDataPointer and addrMessageDataLength).
+				// Save the equality result (1 if they match, 0 otherwise) into addrResult.
+				codeByteBuffer.put(OpCode.EXT_FUN_RET_DAT_2.compile(FunctionCode.CHECK_HASH160_WITH_B, addrResult, addrMessageDataPointer, addrMessageDataLength));
+				// If hashes don't match, addrResult will be zero so go find another transaction
+				codeByteBuffer.put(OpCode.BZR_DAT.compile(addrResult, calcOffset(codeByteBuffer, labelTradeTxLoop)));
+
+				/* Success! Pay arranged amount to intended recipient */
+
+				// Load B register with intended recipient address (as pointed to by addrQortalRecipientPointer)
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.SET_B_IND, addrQortalRecipientPointer));
+				// Pay AT's balance to recipient
+				codeByteBuffer.put(OpCode.EXT_FUN_DAT.compile(FunctionCode.PAY_TO_ADDRESS_IN_B, addrRedeemPayoutAmount));
+				// Fall-through to refunding any remaining balance back to AT creator
+
+				/* Refund balance back to AT creator */
+				labelRefund = codeByteBuffer.position();
+
+				// Load B register with AT creator's address.
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PUT_CREATOR_INTO_B));
+				// Pay AT's balance back to AT's creator.
+				codeByteBuffer.put(OpCode.EXT_FUN.compile(FunctionCode.PAY_ALL_TO_ADDRESS_IN_B));
+				// We're finished forever
+				codeByteBuffer.put(OpCode.FIN_IMD.compile());
+			} catch (CompilationException e) {
+				throw new IllegalStateException("Unable to compile BTC-QORT ACCT?", e);
+			}
+		}
+
+		codeByteBuffer.flip();
+
+		byte[] codeBytes = new byte[codeByteBuffer.limit()];
+		codeByteBuffer.get(codeBytes);
+
+		assert Arrays.equals(Crypto.digest(codeBytes), BTCACCT.CODE_BYTES_HASH)
+			: String.format("BTCACCT.CODE_BYTES_HASH mismatch: expected %s, actual %s", HashCode.fromBytes(CODE_BYTES_HASH), HashCode.fromBytes(Crypto.digest(codeBytes)));
+
+		final short ciyamAtVersion = 2;
+		final short numCallStackPages = 0;
+		final short numUserStackPages = 0;
+		final long minActivationAmount = 0L;
+
+		return MachineState.toCreationBytes(ciyamAtVersion, codeBytes, dataByteBuffer.array(), numCallStackPages, numUserStackPages, minActivationAmount);
+	}
+
+	/**
+	 * Returns CrossChainTradeData with useful info extracted from AT.
+	 * 
+	 * @param repository
+	 * @param atAddress
+	 * @throws DataException
+	 */
+	public static CrossChainTradeData populateTradeData(Repository repository, ATData atData) throws DataException {
+		String atAddress = atData.getATAddress();
+
+		ATStateData atStateData = repository.getATRepository().getLatestATState(atAddress);
+		byte[] stateData = atStateData.getStateData();
+
+		QortalAtLoggerFactory loggerFactory = QortalAtLoggerFactory.getInstance();
+		byte[] dataBytes = MachineState.extractDataBytes(loggerFactory, stateData);
+
+		CrossChainTradeData tradeData = new CrossChainTradeData();
+		tradeData.qortalAtAddress = atAddress;
+		tradeData.qortalCreator = Crypto.toAddress(atData.getCreatorPublicKey());
+		tradeData.creationTimestamp = atData.getCreation();
+
+		Account atAccount = new Account(repository, atAddress);
+		tradeData.qortBalance = atAccount.getConfirmedBalance(Asset.QORT);
+
+		ByteBuffer dataByteBuffer = ByteBuffer.wrap(dataBytes);
+		byte[] addressBytes = new byte[32];
+
+		// Skip AT creator address
+		dataByteBuffer.position(dataByteBuffer.position() + 32);
+
+		// Hash of secret
+		tradeData.secretHash = new byte[20];
+		dataByteBuffer.get(tradeData.secretHash);
+		dataByteBuffer.position(dataByteBuffer.position() + 32 - 20); // skip to 32 bytes
+
+		// Trade timeout
+		tradeData.tradeRefundTimeout = dataByteBuffer.getLong();
+
+		// Initial payout
+		tradeData.initialPayout = dataByteBuffer.getLong();
+
+		// Redeem payout
+		tradeData.redeemPayout = dataByteBuffer.getLong();
+
+		// Expected BTC amount
+		tradeData.expectedBitcoin = dataByteBuffer.getLong();
+
+		// Skip MESSAGE transaction type
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to secretHash
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to Qortal recipient
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to message sender
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip pointer to message data
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Skip message data length
+		dataByteBuffer.position(dataByteBuffer.position() + 8);
+
+		// Qortal recipient (if any)
+		dataByteBuffer.get(addressBytes);
+
+		// Trade offer timeout (AT 'timestamp' converted to Qortal block height)
+		long tradeRefundTimestamp = dataByteBuffer.getLong();
+
+		if (tradeRefundTimestamp != 0) {
+			tradeData.mode = CrossChainTradeData.Mode.TRADE;
+			tradeData.tradeRefundHeight = new Timestamp(tradeRefundTimestamp).blockHeight;
+
+			if (addressBytes[0] != 0)
+				tradeData.qortalRecipient = Base58.encode(Arrays.copyOf(addressBytes, Account.ADDRESS_LENGTH));
+
+			// We'll suggest half of trade timeout
+			CiyamAtSettings ciyamAtSettings = BlockChain.getInstance().getCiyamAtSettings();
+
+			int tradeModeSwitchHeight = (int) (tradeData.tradeRefundHeight - tradeData.tradeRefundTimeout / ciyamAtSettings.minutesPerBlock);
+
+			BlockData blockData = repository.getBlockRepository().fromHeight(tradeModeSwitchHeight);
+			if (blockData != null) {
+				tradeData.tradeModeTimestamp = blockData.getTimestamp(); // NOTE: milliseconds from epoch
+				tradeData.lockTime = (int) (tradeData.tradeModeTimestamp / 1000L + tradeData.tradeRefundTimeout / 2 * 60);
+			}
+		} else {
+			tradeData.mode = CrossChainTradeData.Mode.OFFER;
+		}
+
+		return tradeData;
+	}
+
+	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 != BTCACCT.SECRET_LENGTH)
+					continue;
+
+				return secret;
+			}
+		}
+
+		return null;
+	}
+
+}

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

@@ -0,0 +1,387 @@
+package org.qortal.crosschain;
+
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.Socket;
+import java.net.SocketAddress;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Random;
+import java.util.Scanner;
+import java.util.Set;
+
+import javax.net.ssl.SSLSocket;
+import javax.net.ssl.SSLSocketFactory;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.json.simple.JSONArray;
+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;
+
+public class ElectrumX {
+
+	private static final Logger LOGGER = LogManager.getLogger(ElectrumX.class);
+	private static final Random RANDOM = new Random();
+
+	private static final int DEFAULT_TCP_PORT = 50001;
+	private static final int DEFAULT_SSL_PORT = 50002;
+
+	private static final int BLOCK_HEADER_LENGTH = 80;
+
+	private static final Map<String, ElectrumX> instances = new HashMap<>();
+
+	static class Server {
+		String hostname;
+
+		enum ConnectionType { TCP, SSL };
+		ConnectionType connectionType;
+
+		int port;
+
+		public Server(String hostname, ConnectionType connectionType, int port) {
+			this.hostname = hostname;
+			this.connectionType = connectionType;
+			this.port = port;
+		}
+
+		@Override
+		public boolean equals(Object other) {
+			if (other == this)
+				return true;
+
+			if (!(other instanceof Server))
+				return false;
+
+			Server otherServer = (Server) other;
+
+			return this.connectionType == otherServer.connectionType
+					&& this.port == otherServer.port
+					&& this.hostname.equals(otherServer.hostname);
+		}
+
+		@Override
+		public int hashCode() {
+			return this.hostname.hashCode() ^ this.port;
+		}
+
+		@Override
+		public String toString() {
+			return String.format("%s:%s:%d", this.connectionType.name(), this.hostname, this.port);
+		}
+	}
+	private Set<Server> servers = new HashSet<>();
+
+	private Server currentServer;
+	private Socket socket;
+	private Scanner scanner;
+	private int nextId = 1;
+
+	// Constructors
+
+	private ElectrumX(String bitcoinNetwork) {
+		switch (bitcoinNetwork) {
+			case "MAIN":
+				servers.addAll(Arrays.asList());
+				break;
+
+			case "TEST3":
+				servers.addAll(Arrays.asList(
+						new Server("tn.not.fyi", Server.ConnectionType.TCP, 55001),
+						new Server("tn.not.fyi", Server.ConnectionType.SSL, 55002),
+						new Server("testnet.aranguren.org", Server.ConnectionType.TCP, 51001),
+						new Server("testnet.aranguren.org", Server.ConnectionType.SSL, 51002),
+						new Server("testnet.hsmiths.com", Server.ConnectionType.SSL, 53012)));
+				break;
+
+			case "REGTEST":
+				servers.addAll(Arrays.asList(
+						new Server("localhost", Server.ConnectionType.TCP, DEFAULT_TCP_PORT),
+						new Server("localhost", Server.ConnectionType.SSL, DEFAULT_SSL_PORT)));
+				break;
+
+			default:
+				throw new IllegalArgumentException(String.format("Bitcoin network '%s' unknown", bitcoinNetwork));
+		}
+
+		LOGGER.debug(() -> String.format("Starting ElectrumX support for %s Bitcoin network", bitcoinNetwork));
+		rpc("server.banner");
+	}
+
+	public static synchronized ElectrumX getInstance(String bitcoinNetwork) {
+		if (!instances.containsKey(bitcoinNetwork))
+			instances.put(bitcoinNetwork, new ElectrumX(bitcoinNetwork));
+
+		return instances.get(bitcoinNetwork);
+	}
+
+	// Methods for use by other classes
+
+	public Integer getCurrentHeight() {
+		JSONObject blockJson = (JSONObject) this.rpc("blockchain.headers.subscribe");
+		if (blockJson == null || !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"))
+			return null;
+
+		Long returnedCount = (Long) blockJson.get("count");
+		String hex = (String) blockJson.get("hex");
+
+		byte[] raw = HashCode.fromString(hex).asBytes();
+		if (raw.length != returnedCount * BLOCK_HEADER_LENGTH)
+			return null;
+
+		List<byte[]> rawBlockHeaders = new ArrayList<>(returnedCount.intValue());
+		for (int i = 0; i < returnedCount; ++i)
+			rawBlockHeaders.add(Arrays.copyOfRange(raw, i * BLOCK_HEADER_LENGTH, (i + 1) * BLOCK_HEADER_LENGTH));
+
+		return rawBlockHeaders;
+	}
+
+	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"))
+			return null;
+
+		return (Long) balanceJson.get("confirmed");
+	}
+
+	public List<Pair<byte[], Integer>> 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)
+			return null;
+
+		List<Pair<byte[], Integer>> unspentOutputs = new ArrayList<>();
+		for (Object rawUnspent : unspentJson) {
+			JSONObject unspent = (JSONObject) rawUnspent;
+
+			byte[] txHash = HashCode.fromString((String) unspent.get("tx_hash")).asBytes();
+			int outputIndex = ((Long) unspent.get("tx_pos")).intValue();
+
+			unspentOutputs.add(new Pair<>(txHash, outputIndex));
+		}
+
+		return unspentOutputs;
+	}
+
+	public byte[] getRawTransaction(byte[] txHash) {
+		String rawTransactionHex = (String) this.rpc("blockchain.transaction.get", HashCode.fromBytes(txHash).toString());
+		if (rawTransactionHex == null)
+			return null;
+
+		return HashCode.fromString(rawTransactionHex).asBytes();
+	}
+
+	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)
+			return null;
+
+		List<byte[]> rawTransactions = new ArrayList<>();
+
+		for (Object rawTransactionInfo : transactionsJson) {
+			JSONObject transactionInfo = (JSONObject) rawTransactionInfo;
+
+			// We only want confirmed transactions
+			if (!transactionInfo.containsKey("height"))
+				continue;
+
+			String txHash = (String) transactionInfo.get("tx_hash");
+			String rawTransactionHex = (String) this.rpc("blockchain.transaction.get", txHash);
+			if (rawTransactionHex == null)
+				return null;
+
+			rawTransactions.add(HashCode.fromString(rawTransactionHex).asBytes());
+		}
+
+		return rawTransactions;
+	}
+
+	public boolean broadcastTransaction(byte[] transactionBytes) {
+		Object rawBroadcastResult = this.rpc("blockchain.transaction.broadcast", HashCode.fromBytes(transactionBytes).toString());
+		if (rawBroadcastResult == null)
+			return false;
+
+		// If result is a String, then it is simply transaction hash.
+		// Otherwise result is JSON and probably contains error info instead.
+		return rawBroadcastResult instanceof String;
+	}
+
+	// Class-private utility methods
+
+	private Set<Server> serverPeersSubscribe() {
+		Set<Server> newServers = new HashSet<>();
+
+		JSONArray peers = (JSONArray) this.connectedRpc("server.peers.subscribe");
+		if (peers == null)
+			return newServers;
+
+		for (Object rawPeer : peers) {
+			JSONArray peer = (JSONArray) rawPeer;
+			if (peer.size() < 3)
+				continue;
+
+			String hostname = (String) peer.get(1);
+			JSONArray features = (JSONArray) peer.get(2);
+
+			for (Object rawFeature : features) {
+				String feature = (String) rawFeature;
+				Server.ConnectionType connectionType = null;
+				int port = -1;
+
+				switch (feature.charAt(0)) {
+					case 's':
+						connectionType = Server.ConnectionType.SSL;
+						port = DEFAULT_SSL_PORT;
+						break;
+
+					case 't':
+						connectionType = Server.ConnectionType.TCP;
+						port = DEFAULT_TCP_PORT;
+						break;
+				}
+
+				if (connectionType == null)
+					continue;
+
+				// Possible non-default port?
+				if (feature.length() > 1)
+					try {
+						port = Integer.parseInt(feature.substring(1));
+					} catch (NumberFormatException e) {
+						// no good
+						continue; // for-loop above
+					}
+
+				Server newServer = new Server(hostname, connectionType, port);
+				newServers.add(newServer);
+			}
+		}
+
+		return newServers;
+	}
+
+	private synchronized Object rpc(String method, Object...params) {
+		while (haveConnection()) {
+			Object response = connectedRpc(method, params);
+			if (response != null)
+				return response;
+
+			this.currentServer = null;
+			try {
+				this.socket.close();
+			} catch (IOException e) {
+				/* ignore */
+			}
+			this.scanner = null;
+		}
+
+		return null;
+	}
+
+	private boolean haveConnection() {
+		if (this.currentServer != null)
+			return true;
+
+		List<Server> remainingServers = new ArrayList<>(this.servers);
+
+		while (!remainingServers.isEmpty()) {
+			Server server = remainingServers.remove(RANDOM.nextInt(remainingServers.size()));
+			LOGGER.trace(() -> String.format("Connecting to %s", server));
+
+			try {
+				SocketAddress endpoint = new InetSocketAddress(server.hostname, server.port);
+				int timeout = 5000; // ms
+
+				this.socket = new Socket();
+				this.socket.connect(endpoint, timeout);
+				this.socket.setTcpNoDelay(true);
+
+				if (server.connectionType == Server.ConnectionType.SSL) {
+					SSLSocketFactory factory = TrustlessSSLSocketFactory.getSocketFactory();
+					this.socket = (SSLSocket) factory.createSocket(this.socket, server.hostname, server.port, true);
+				}
+
+				this.scanner = new Scanner(this.socket.getInputStream());
+				this.scanner.useDelimiter("\n");
+
+				// Check connection works by asking for more servers
+				Set<Server> moreServers = serverPeersSubscribe();
+				moreServers.removeAll(this.servers);
+				remainingServers.addAll(moreServers);
+				this.servers.addAll(moreServers);
+
+				LOGGER.debug(() -> String.format("Connected to %s", server));
+				this.currentServer = server;
+				return true;
+			} catch (IOException e) {
+				// Try another server...
+				this.socket = null;
+				this.scanner = null;
+			}
+		}
+
+		return false;
+	}
+
+	@SuppressWarnings("unchecked")
+	private Object connectedRpc(String method, Object...params) {
+		JSONObject requestJson = new JSONObject();
+		requestJson.put("id", this.nextId++);
+		requestJson.put("method", method);
+
+		JSONArray requestParams = new JSONArray();
+		requestParams.addAll(Arrays.asList(params));
+		requestJson.put("params", requestParams);
+
+		String request = requestJson.toJSONString() + "\n";
+		LOGGER.trace(() -> String.format("Request: %s", request));
+
+		final String response;
+
+		try {
+			this.socket.getOutputStream().write(request.getBytes());
+			response = scanner.next();
+		} catch (IOException | NoSuchElementException e) {
+			return null;
+		}
+
+		LOGGER.trace(() -> String.format("Response: %s", response));
+
+		if (response.isEmpty())
+			return null;
+
+		JSONObject responseJson = (JSONObject) JSONValue.parse(response);
+		if (responseJson == null)
+			return null;
+
+		return responseJson.get("result");
+	}
+
+}

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

@@ -4,16 +4,23 @@ import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.Arrays;
 
+import org.bouncycastle.crypto.params.Ed25519PrivateKeyParameters;
+import org.bouncycastle.crypto.params.X25519PrivateKeyParameters;
+import org.bouncycastle.crypto.params.X25519PublicKeyParameters;
+import org.bouncycastle.math.ec.rfc8032.Ed25519;
 import org.qortal.account.Account;
-import org.qortal.block.BlockChain;
 import org.qortal.utils.Base58;
 
 import com.google.common.primitives.Bytes;
 
-public class Crypto {
+public abstract class Crypto {
 
-	public static final byte ADDRESS_VERSION = 58;
-	public static final byte AT_ADDRESS_VERSION = 23;
+	public static final int SIGNATURE_LENGTH = 64;
+	public static final int SHARED_SECRET_LENGTH = 32;
+
+	public static final byte ADDRESS_VERSION = 58; // Q
+	public static final byte AT_ADDRESS_VERSION = 23; // A
+	public static final byte NODE_ADDRESS_VERSION = 53; // N
 
 	/**
 	 * Returns 32-byte SHA-256 digest of message passed in input.
@@ -59,24 +66,29 @@ public class Crypto {
 		return Bytes.concat(digest, digest);
 	}
 
-	@SuppressWarnings("deprecation")
+	/** Returns RMD160(SHA256(data)) */
+	public static byte[] hash160(byte[] data) {
+		byte[] interim = digest(data);
+
+		try {
+			MessageDigest md160 = MessageDigest.getInstance("RIPEMD160");
+			return md160.digest(interim);
+		} catch (NoSuchAlgorithmException e) {
+			throw new RuntimeException("RIPEMD160 message digest not available");
+		}
+	}
+
 	private static String toAddress(byte addressVersion, byte[] input) {
 		// SHA2-256 input to create new data and of known size
 		byte[] inputHash = digest(input);
 
 		// Use RIPEMD160 to create shorter address
-		if (BlockChain.getInstance().getUseBrokenMD160ForAddresses()) {
-			// Legacy BROKEN MD160
-			BrokenMD160 brokenMD160 = new BrokenMD160();
-			inputHash = brokenMD160.digest(inputHash);
-		} else {
-			// Use legit MD160
-			try {
-				MessageDigest md160 = MessageDigest.getInstance("RIPEMD160");
-				inputHash = md160.digest(inputHash);
-			} catch (NoSuchAlgorithmException e) {
-				throw new RuntimeException("RIPEMD160 message digest not available");
-			}
+		// Use legit MD160
+		try {
+			MessageDigest md160 = MessageDigest.getInstance("RIPEMD160");
+			inputHash = md160.digest(inputHash);
+		} catch (NoSuchAlgorithmException e) {
+			throw new RuntimeException("RIPEMD160 message digest not available");
 		}
 
 		// Create address data using above hash and addressVersion (prepended)
@@ -104,18 +116,23 @@ public class Crypto {
 		return toAddress(AT_ADDRESS_VERSION, signature);
 	}
 
+	public static String toNodeAddress(byte[] publicKey) {
+		return toAddress(NODE_ADDRESS_VERSION, publicKey);
+	}
+
 	public static boolean isValidAddress(String address) {
 		return isValidTypedAddress(address, ADDRESS_VERSION, AT_ADDRESS_VERSION);
 	}
 
+	public static boolean isValidAddress(byte[] addressBytes) {
+		return areValidTypedAddressBytes(addressBytes, ADDRESS_VERSION, AT_ADDRESS_VERSION);
+	}
+
 	public static boolean isValidAtAddress(String address) {
 		return isValidTypedAddress(address, AT_ADDRESS_VERSION);
 	}
 
 	private static boolean isValidTypedAddress(String address, byte...addressVersions) {
-		if (addressVersions == null || addressVersions.length == 0)
-			return false;
-
 		byte[] addressBytes;
 
 		try {
@@ -125,6 +142,13 @@ public class Crypto {
 			return false;
 		}
 
+		return areValidTypedAddressBytes(addressBytes, addressVersions);
+	}
+
+	private static boolean areValidTypedAddressBytes(byte[] addressBytes, byte...addressVersions) {
+		if (addressVersions == null || addressVersions.length == 0)
+			return false;
+
 		// Check address length
 		if (addressBytes == null || addressBytes.length != Account.ADDRESS_LENGTH)
 			return false;
@@ -142,4 +166,33 @@ public class Crypto {
 		return false;
 	}
 
+	public static boolean verify(byte[] publicKey, byte[] signature, byte[] message) {
+		try {
+			return Ed25519.verify(signature, 0, publicKey, 0, message, 0, message.length);
+		} catch (Exception e) {
+			return false;
+		}
+	}
+
+	public static byte[] sign(Ed25519PrivateKeyParameters edPrivateKeyParams, byte[] message) {
+		byte[] signature = new byte[SIGNATURE_LENGTH];
+
+		edPrivateKeyParams.sign(Ed25519.Algorithm.Ed25519, edPrivateKeyParams.generatePublicKey(), null, message, 0, message.length, signature, 0);
+
+		return signature;
+	}
+
+	public static byte[] getSharedSecret(byte[] privateKey, byte[] publicKey) {
+		byte[] x25519PrivateKey = BouncyCastle25519.toX25519PrivateKey(privateKey);
+		X25519PrivateKeyParameters xPrivateKeyParams = new X25519PrivateKeyParameters(x25519PrivateKey, 0);
+
+		byte[] x25519PublicKey = BouncyCastle25519.toX25519PublicKey(publicKey);
+		X25519PublicKeyParameters xPublicKeyParams = new X25519PublicKeyParameters(x25519PublicKey, 0);
+
+		byte[] sharedSecret = new byte[SHARED_SECRET_LENGTH];
+		xPrivateKeyParams.generateSecret(xPublicKeyParams, sharedSecret, 0);
+
+		return sharedSecret;
+	}
+
 }

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

@@ -1,83 +1,112 @@
 package org.qortal.crypto;
 
-import com.google.common.primitives.Bytes;
+import java.nio.ByteBuffer;
 
 public class MemoryPoW {
 
-	public static final int WORK_BUFFER_LENGTH = 4 * 1024 * 1024;
-	private static final int WORK_BUFFER_LENGTH_MASK = WORK_BUFFER_LENGTH - 1;
-
-	private static final int HASH_LENGTH = 32;
-	private static final int HASH_LENGTH_MASK = HASH_LENGTH - 1;
-
-	public static Integer compute(byte[] data, int start, int range, int difficulty) {
-		if (range < 1)
-			throw new IllegalArgumentException("range must be at least 1");
-
-		if (difficulty < 1)
-			throw new IllegalArgumentException("difficulty must be at least 1");
-
+	public static Integer compute2(byte[] data, int workBufferLength, long difficulty) {
 		// Hash data with SHA256
 		byte[] hash = Crypto.digest(data);
 
-		assert hash.length == HASH_LENGTH;
+		long[] longHash = new long[4];
+		ByteBuffer byteBuffer = ByteBuffer.wrap(hash);
+		longHash[0] = byteBuffer.getLong();
+		longHash[1] = byteBuffer.getLong();
+		longHash[2] = byteBuffer.getLong();
+		longHash[3] = byteBuffer.getLong();
+		byteBuffer = null;
 
-		byte[] perturbedHash = new byte[HASH_LENGTH];
-		byte[] workBuffer = new byte[WORK_BUFFER_LENGTH];
-		byte[] bufferHash = new byte[HASH_LENGTH];
+		int longBufferLength = workBufferLength / 8;
+		long[] workBuffer = new long[longBufferLength];
+		long[] state = new long[4];
+
+		long seed = 8682522807148012L;
+		long seedMultiplier = 1181783497276652981L;
 
 		// For each nonce...
-		for (int nonce = start; nonce < start + range; ++nonce) {
-			// Perturb hash using nonce
-			int temp = nonce;
-			for (int hi = 0; hi < HASH_LENGTH; ++hi) {
-				perturbedHash[hi] = (byte) (hash[hi] ^ (temp & 0xff));
-				temp >>>= 1;
+		int nonce = -1;
+		long result = 0;
+		do {
+			++nonce;
+
+			seed *= seedMultiplier; // per nonce
+
+			state[0] = longHash[0] ^ seed;
+			state[1] = longHash[1] ^ seed;
+			state[2] = longHash[2] ^ seed;
+			state[3] = longHash[3] ^ seed;
+
+			// Fill work buffer with random
+			for (int i = 0; i < workBuffer.length; ++i)
+				workBuffer[i] = xoshiro256p(state);
+
+			// Random bounce through whole buffer
+			result = workBuffer[0];
+			for (int i = 0; i < 1024; ++i) {
+				int index = (int) (xoshiro256p(state) & Integer.MAX_VALUE) % workBuffer.length;
+				result ^= workBuffer[index];
 			}
 
-			// Fill large working memory buffer using hash, further perturbing as we go
-			int wanderingBufferOffset = 0;
-			byte ch = 0;
+			// Return if final value > difficulty
+		} while (Long.numberOfLeadingZeros(result) < difficulty);
 
-			int hashOffset = 0;
+		return nonce;
+	}
 
-			for (int workBufferOffset = 0; workBufferOffset < WORK_BUFFER_LENGTH; workBufferOffset += HASH_LENGTH) {
-				System.arraycopy(perturbedHash, 0, workBuffer, workBufferOffset, HASH_LENGTH);
+	public static boolean verify2(byte[] data, int workBufferLength, long difficulty, int nonce) {
+		// Hash data with SHA256
+		byte[] hash = Crypto.digest(data);
 
-				hashOffset = ++hashOffset & HASH_LENGTH_MASK;
+		long[] longHash = new long[4];
+		ByteBuffer byteBuffer = ByteBuffer.wrap(hash);
+		longHash[0] = byteBuffer.getLong();
+		longHash[1] = byteBuffer.getLong();
+		longHash[2] = byteBuffer.getLong();
+		longHash[3] = byteBuffer.getLong();
+		byteBuffer = null;
 
-				ch += perturbedHash[hashOffset];
+		int longBufferLength = workBufferLength / 8;
+		long[] workBuffer = new long[longBufferLength];
+		long[] state = new long[4];
 
-				for (byte hi = 0; hi < HASH_LENGTH; ++hi) {
-					byte hashByte = perturbedHash[hi];
-					wanderingBufferOffset = (wanderingBufferOffset << 3) ^ (hashByte & 0xff);
+		long seed = 8682522807148012L;
+		long seedMultiplier = 1181783497276652981L;
 
-					perturbedHash[hi] = (byte) (hashByte ^ (ch + hi));
-				}
+		for (int i = 0; i <= nonce; ++i)
+			seed *= seedMultiplier;
 
-				workBuffer[wanderingBufferOffset & WORK_BUFFER_LENGTH_MASK] ^= 0xAA;
+		state[0] = longHash[0] ^ seed;
+		state[1] = longHash[1] ^ seed;
+		state[2] = longHash[2] ^ seed;
+		state[3] = longHash[3] ^ seed;
 
-				// final int finalWanderingBufferOffset = wanderingBufferOffset & WORK_BUFFER_LENGTH_MASK;
-				// System.out.println(String.format("wanderingBufferOffset: 0x%08x / 0x%08x - %02d%%", finalWanderingBufferOffset, WORK_BUFFER_LENGTH, finalWanderingBufferOffset * 100 / WORK_BUFFER_LENGTH));
-			}
+		// Fill work buffer with random
+		for (int i = 0; i < workBuffer.length; ++i)
+			workBuffer[i] = xoshiro256p(state);
 
-			Bytes.reverse(workBuffer);
-
-			// bufferHash = Crypto.digest(workBuffer);
-			System.arraycopy(workBuffer, 0, bufferHash, 0, HASH_LENGTH);
-
-			int hi = 0;
-			for (hi = 0; hi < difficulty; ++hi)
-				if (bufferHash[hi] != 0)
-					break;
-
-			if (hi == difficulty)
-				return nonce;
-
-			Thread.yield();
+		// Random bounce through whole buffer
+		long result = workBuffer[0];
+		for (int i = 0; i < 1024; ++i) {
+			int index = (int) (xoshiro256p(state) & Integer.MAX_VALUE) % workBuffer.length;
+			result ^= workBuffer[index];
 		}
 
-		return null;
+		return Long.numberOfLeadingZeros(result) >= difficulty;
+	}
+
+	private static final long xoshiro256p(long[] state) {
+		final long result = state[0] + state[3];
+		final long temp = state[1] << 17;
+
+		state[2] ^= state[0];
+		state[3] ^= state[1];
+		state[1] ^= state[2];
+		state[0] ^= state[3];
+
+		state[2] ^= temp;
+		state[3] = (state[3] << 45) | (state[3] >>> (64 - 45)); // rol64(s[3], 45);
+
+		return result;
 	}
 
 }

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

@@ -0,0 +1,42 @@
+package org.qortal.crypto;
+
+import java.security.cert.X509Certificate;
+
+import javax.net.ssl.SSLContext;
+import javax.net.ssl.SSLSocketFactory;
+import javax.net.ssl.TrustManager;
+import javax.net.ssl.X509TrustManager;
+
+public abstract class TrustlessSSLSocketFactory {
+
+	// Create a trust manager that does not validate certificate chains
+	private static final TrustManager[] TRUSTLESS_MANAGER = new TrustManager[] {
+		new X509TrustManager() {
+			public java.security.cert.X509Certificate[] getAcceptedIssuers() {
+				return new X509Certificate[0];
+			}
+
+			public void checkClientTrusted(java.security.cert.X509Certificate[] certs, String authType) {
+			}
+
+			public void checkServerTrusted(java.security.cert.X509Certificate[] certs, String authType) {
+			}
+		}
+	};
+
+	// Install the all-trusting trust manager
+	private static final SSLContext sc;
+	static {
+		try {
+			sc = SSLContext.getInstance("SSL");
+			sc.init(null, TRUSTLESS_MANAGER, new java.security.SecureRandom());
+		} catch (Exception e) {
+			throw new RuntimeException(e);
+		}
+	}
+
+	public static SSLSocketFactory getSocketFactory() {
+		return sc.getSocketFactory();
+	}
+
+}

src/main/java/org/qortal/data/PaymentData.java

@@ -1,18 +1,21 @@
 package org.qortal.data;
 
-import java.math.BigDecimal;
-
 import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
+import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
 
 // All properties to be converted to JSON via JAXB
 @XmlAccessorType(XmlAccessType.FIELD)
 public class PaymentData {
 
 	// Properties
+
 	private String recipient;
+
 	private long assetId;
-	private BigDecimal amount;
+
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long amount;
 
 	// Constructors
 
@@ -20,7 +23,7 @@ public class PaymentData {
 	protected PaymentData() {
 	}
 
-	public PaymentData(String recipient, long assetId, BigDecimal amount) {
+	public PaymentData(String recipient, long assetId, long amount) {
 		this.recipient = recipient;
 		this.assetId = assetId;
 		this.amount = amount;
@@ -36,7 +39,7 @@ public class PaymentData {
 		return this.assetId;
 	}
 
-	public BigDecimal getAmount() {
+	public long getAmount() {
 		return this.amount;
 	}
 

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

@@ -1,9 +1,11 @@
 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.adapters.XmlJavaTypeAdapter;
+
+import org.qortal.utils.Amounts;
 
 // All properties to be converted to JSON via JAXB
 @XmlAccessorType(XmlAccessType.FIELD)
@@ -12,7 +14,9 @@ public class AccountBalanceData {
 	// Properties
 	private String address;
 	private long assetId;
-	private BigDecimal balance;
+
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long balance;
 
 	// Not always present:
 	private Integer height;
@@ -24,19 +28,19 @@ public class AccountBalanceData {
 	protected AccountBalanceData() {
 	}
 
-	public AccountBalanceData(String address, long assetId, BigDecimal balance) {
+	public AccountBalanceData(String address, long assetId, long balance) {
 		this.address = address;
 		this.assetId = assetId;
 		this.balance = balance;
 	}
 
-	public AccountBalanceData(String address, long assetId, BigDecimal balance, int height) {
+	public AccountBalanceData(String address, long assetId, long balance, int height) {
 		this(address, assetId, balance);
 
 		this.height = height;
 	}
 
-	public AccountBalanceData(String address, long assetId, BigDecimal balance, String assetName) {
+	public AccountBalanceData(String address, long assetId, long balance, String assetName) {
 		this(address, assetId, balance);
 
 		this.assetName = assetName;
@@ -52,11 +56,11 @@ public class AccountBalanceData {
 		return this.assetId;
 	}
 
-	public BigDecimal getBalance() {
+	public long getBalance() {
 		return this.balance;
 	}
 
-	public void setBalance(BigDecimal balance) {
+	public void setBalance(long balance) {
 		this.balance = balance;
 	}
 
@@ -68,4 +72,8 @@ public class AccountBalanceData {
 		return this.assetName;
 	}
 
+	public String toString() {
+		return String.format("%s has %s %s [assetId %d]", this.address, Amounts.prettyAmount(this.balance), (assetName != null ? assetName : ""), assetId);
+	}
+
 }

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

@@ -1,18 +1,23 @@
 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.adapters.XmlJavaTypeAdapter;
 
 // All properties to be converted to JSON via JAXB
 @XmlAccessorType(XmlAccessType.FIELD)
 public class QortFromQoraData {
 
 	// Properties
+
 	private String address;
-	// Not always present:
-	private BigDecimal finalQortFromQora;
+
+	// Not always present
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private Long finalQortFromQora;
+
+	// Not always present
 	private Integer finalBlockHeight;
 
 	// Constructors
@@ -21,7 +26,7 @@ public class QortFromQoraData {
 	protected QortFromQoraData() {
 	}
 
-	public QortFromQoraData(String address, BigDecimal finalQortFromQora, Integer finalBlockHeight) {
+	public QortFromQoraData(String address, Long finalQortFromQora, Integer finalBlockHeight) {
 		this.address = address;
 		this.finalQortFromQora = finalQortFromQora;
 		this.finalBlockHeight = finalBlockHeight;
@@ -33,11 +38,11 @@ public class QortFromQoraData {
 		return this.address;
 	}
 
-	public BigDecimal getFinalQortFromQora() {
+	public Long getFinalQortFromQora() {
 		return this.finalQortFromQora;
 	}
 
-	public void setFinalQortFromQora(BigDecimal finalQortFromQora) {
+	public void setFinalQortFromQora(Long finalQortFromQora) {
 		this.finalQortFromQora = finalQortFromQora;
 	}
 

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

@@ -6,6 +6,9 @@ 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;
 
@@ -23,7 +26,9 @@ public class RewardShareData {
 
 	private String recipient;
 	private byte[] rewardSharePublicKey;
-	private BigDecimal sharePercent;
+
+	@XmlJavaTypeAdapter(value = org.qortal.api.RewardSharePercentTypeAdapter.class)
+	private int sharePercent;
 
 	// Constructors
 
@@ -32,7 +37,7 @@ public class RewardShareData {
 	}
 
 	// Used when fetching from repository
-	public RewardShareData(byte[] minterPublicKey, String minter, String recipient, byte[] rewardSharePublicKey, BigDecimal sharePercent) {
+	public RewardShareData(byte[] minterPublicKey, String minter, String recipient, byte[] rewardSharePublicKey, int sharePercent) {
 		this.minterPublicKey = minterPublicKey;
 		this.minter = minter;
 		this.recipient = recipient;
@@ -58,13 +63,25 @@ public class RewardShareData {
 		return this.rewardSharePublicKey;
 	}
 
-	public BigDecimal getSharePercent() {
+	/** Returns share percent scaled by 100. i.e. 12.34% is represented by 1234 */
+	public int getSharePercent() {
 		return this.sharePercent;
 	}
 
+	// Some JAXB/API-related getters
+
 	@XmlElement(name = "mintingAccount")
 	public String getMintingAccount() {
 		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/asset/AssetData.java

@@ -20,19 +20,26 @@ public class AssetData {
 	private String data;
 	private boolean isUnspendable;
 	private int creationGroupId;
+
 	// No need to expose this via API
 	@XmlTransient
 	@Schema(hidden = true)
 	private byte[] reference;
 
+	// For internal use only
+	@XmlTransient
+	@Schema(hidden = true)
+	private String reducedAssetName;
+
 	// Constructors
 
-	// necessary for JAX-RS serialization
+	// necessary for JAXB serialization
 	protected AssetData() {
 	}
 
 	// NOTE: key is Long, not long, because it can be null if asset ID/key not yet assigned.
-	public AssetData(Long assetId, String owner, String name, String description, long quantity, boolean isDivisible, String data, boolean isUnspendable, int creationGroupId, byte[] reference) {
+	public AssetData(Long assetId, String owner, String name, String description, long quantity, boolean isDivisible,
+			String data, boolean isUnspendable, int creationGroupId, byte[] reference, String reducedAssetName) {
 		this.assetId = assetId;
 		this.owner = owner;
 		this.name = name;
@@ -43,11 +50,13 @@ public class AssetData {
 		this.isUnspendable = isUnspendable;
 		this.creationGroupId = creationGroupId;
 		this.reference = reference;
+		this.reducedAssetName = reducedAssetName;
 	}
 
 	// New asset with unassigned assetId
-	public AssetData(String owner, String name, String description, long quantity, boolean isDivisible, String data, boolean isUnspendable, int creationGroupId, byte[] reference) {
-		this(null, owner, name, description, quantity, isDivisible, data, isUnspendable, creationGroupId, reference);
+	public AssetData(String owner, String name, String description, long quantity, boolean isDivisible, String data,
+			boolean isUnspendable, int creationGroupId, byte[] reference, String reducedAssetName) {
+		this(null, owner, name, description, quantity, isDivisible, data, isUnspendable, creationGroupId, reference, reducedAssetName);
 	}
 
 	// Getters/Setters
@@ -84,7 +93,7 @@ public class AssetData {
 		return this.quantity;
 	}
 
-	public boolean getIsDivisible() {
+	public boolean isDivisible() {
 		return this.isDivisible;
 	}
 
@@ -96,7 +105,7 @@ public class AssetData {
 		this.data = data;
 	}
 
-	public boolean getIsUnspendable() {
+	public boolean isUnspendable() {
 		return this.isUnspendable;
 	}
 
@@ -112,4 +121,12 @@ public class AssetData {
 		this.reference = reference;
 	}
 
+	public String getReducedAssetName() {
+		return this.reducedAssetName;
+	}
+
+	public void setReducedAssetName(String reducedAssetName) {
+		this.reducedAssetName = reducedAssetName;
+	}
+
 }

src/main/java/org/qortal/data/asset/OrderData.java

@@ -1,10 +1,9 @@
 package org.qortal.data.asset;
 
-import java.math.BigDecimal;
-
 import javax.xml.bind.Marshaller;
 import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
+import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
 
 import org.qortal.crypto.Crypto;
 
@@ -26,13 +25,16 @@ public class OrderData implements Comparable<OrderData> {
 	private long wantAssetId;
 
 	@Schema(description = "amount of highest-assetID asset to trade")
-	private BigDecimal amount;
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long amount;
 
 	@Schema(description = "price in lowest-assetID asset / highest-assetID asset")
-	private BigDecimal price;
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long price;
 
 	@Schema(description = "how much of \"amount\" has traded")
-	private BigDecimal fulfilled;
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long fulfilled;
 
 	private long timestamp;
 
@@ -73,26 +75,23 @@ public class OrderData implements Comparable<OrderData> {
 		if (this.creator == null && this.creatorPublicKey != null)
 			this.creator = Crypto.toAddress(this.creatorPublicKey);
 
+		this.amountAssetId = Math.max(this.haveAssetId, this.wantAssetId);
+
 		// If we don't have the extra asset name fields then we can't fill in the others
 		if (this.haveAssetName == null)
 			return;
 
-		// TODO: fill in for 'old' pricing scheme
-
-		// 'new' pricing scheme
 		if (this.haveAssetId < this.wantAssetId) {
-			this.amountAssetId = this.wantAssetId;
 			this.amountAssetName = this.wantAssetName;
 			this.pricePair = this.haveAssetName + "/" + this.wantAssetName;
 		} else {
-			this.amountAssetId = this.haveAssetId;
 			this.amountAssetName = this.haveAssetName;
 			this.pricePair = this.wantAssetName + "/" + this.haveAssetName;
 		}
 	}
 
 	/** Constructs OrderData using data from repository, including optional API fields. */
-	public OrderData(byte[] orderId, byte[] creatorPublicKey, long haveAssetId, long wantAssetId, BigDecimal amount, BigDecimal fulfilled, BigDecimal price, long timestamp,
+	public OrderData(byte[] orderId, byte[] creatorPublicKey, long haveAssetId, long wantAssetId, long amount, long fulfilled, long price, long timestamp,
 			boolean isClosed, boolean isFulfilled, String haveAssetName, String wantAssetName) {
 		this.orderId = orderId;
 		this.creatorPublicKey = creatorPublicKey;
@@ -110,13 +109,13 @@ public class OrderData implements Comparable<OrderData> {
 	}
 
 	/** Constructs OrderData using data from repository, excluding optional API fields. */
-	public OrderData(byte[] orderId, byte[] creatorPublicKey, long haveAssetId, long wantAssetId, BigDecimal amount, BigDecimal fulfilled, BigDecimal price, long timestamp, boolean isClosed, boolean isFulfilled) {
+	public OrderData(byte[] orderId, byte[] creatorPublicKey, long haveAssetId, long wantAssetId, long amount, long fulfilled, long price, long timestamp, boolean isClosed, boolean isFulfilled) {
 		this(orderId, creatorPublicKey, haveAssetId, wantAssetId, amount, fulfilled, price, timestamp, isClosed, isFulfilled, null, null);
 	}
 
 	/** Constructs OrderData using data typically received from network. */
-	public OrderData(byte[] orderId, byte[] creatorPublicKey, long haveAssetId, long wantAssetId, BigDecimal amount, BigDecimal price, long timestamp) {
-		this(orderId, creatorPublicKey, haveAssetId, wantAssetId, amount, BigDecimal.ZERO.setScale(8), price, timestamp, false, false);
+	public OrderData(byte[] orderId, byte[] creatorPublicKey, long haveAssetId, long wantAssetId, long amount, long price, long timestamp) {
+		this(orderId, creatorPublicKey, haveAssetId, wantAssetId, amount, 0 /*fulfilled*/, price, timestamp, false, false);
 	}
 
 	// Getters/setters
@@ -137,19 +136,19 @@ public class OrderData implements Comparable<OrderData> {
 		return this.wantAssetId;
 	}
 
-	public BigDecimal getAmount() {
+	public long getAmount() {
 		return this.amount;
 	}
 
-	public BigDecimal getFulfilled() {
+	public long getFulfilled() {
 		return this.fulfilled;
 	}
 
-	public void setFulfilled(BigDecimal fulfilled) {
+	public void setFulfilled(long fulfilled) {
 		this.fulfilled = fulfilled;
 	}
 
-	public BigDecimal getPrice() {
+	public long getPrice() {
 		return this.price;
 	}
 
@@ -198,7 +197,7 @@ public class OrderData implements Comparable<OrderData> {
 	@Override
 	public int compareTo(OrderData orderData) {
 		// Compare using prices
-		return this.price.compareTo(orderData.getPrice());
+		return Long.compare(this.price, orderData.getPrice());
 	}
 
 }

src/main/java/org/qortal/data/asset/RecentTradeData.java

@@ -20,9 +20,7 @@ public class RecentTradeData {
 
 	private BigDecimal amount;
 
-	@Schema(
-		description = "when trade happened"
-	)
+	@Schema(description = "when trade happened")
 	private long timestamp;
 
 	// Constructors
@@ -31,11 +29,11 @@ public class RecentTradeData {
 	protected RecentTradeData() {
 	}
 
-	public RecentTradeData(long assetId, long otherAssetId, BigDecimal otherAmount, BigDecimal amount, long timestamp) {
+	public RecentTradeData(long assetId, long otherAssetId, long otherAmount, long amount, long timestamp) {
 		this.assetId = assetId;
 		this.otherAssetId = otherAssetId;
-		this.otherAmount = otherAmount;
-		this.amount = amount;
+		this.otherAmount = BigDecimal.valueOf(otherAmount, 8);
+		this.amount = BigDecimal.valueOf(amount, 8);
 		this.timestamp = timestamp;
 	}
 

src/main/java/org/qortal/data/asset/TradeData.java

@@ -1,12 +1,11 @@
 package org.qortal.data.asset;
 
-import java.math.BigDecimal;
-
 import javax.xml.bind.Marshaller;
 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 io.swagger.v3.oas.annotations.media.Schema;
 import io.swagger.v3.oas.annotations.media.Schema.AccessMode;
@@ -24,17 +23,17 @@ public class TradeData {
 	@XmlElement(name = "targetOrderId")
 	private byte[] target;
 
-	@Schema(name = "targetAmount", description = "amount traded from target")
-	@XmlElement(name = "targetAmount")
-	private BigDecimal targetAmount;
+	@Schema(description = "amount traded from target")
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long targetAmount;
 
-	@Schema(name = "initiatorAmount", description = "amount traded from initiator")
-	@XmlElement(name = "initiatorAmount")
-	private BigDecimal initiatorAmount;
+	@Schema(description = "amount traded from initiator")
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long initiatorAmount;
 
-	@Schema(name = "initiatorSaving", description = "amount refunded to initiator due to price improvement")
-	@XmlElement(name = "initiatorSaving")
-	private BigDecimal initiatorSaving;
+	@Schema(description = "amount refunded to initiator due to price improvement")
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long initiatorSaving;
 
 	@Schema(description = "when trade happened")
 	private long timestamp;
@@ -95,7 +94,7 @@ public class TradeData {
 		}
 	}
 
-	public TradeData(byte[] initiator, byte[] target, BigDecimal targetAmount, BigDecimal initiatorAmount, BigDecimal initiatorSaving, long timestamp,
+	public TradeData(byte[] initiator, byte[] target, long targetAmount, long initiatorAmount, long initiatorSaving, long timestamp,
 			Long haveAssetId, String haveAssetName, Long wantAssetId, String wantAssetName) {
 		this.initiator = initiator;
 		this.target = target;
@@ -110,7 +109,7 @@ public class TradeData {
 		this.wantAssetName = wantAssetName;
 	}
 
-	public TradeData(byte[] initiator, byte[] target, BigDecimal targetAmount, BigDecimal initiatorAmount, BigDecimal initiatorSaving, long timestamp) {
+	public TradeData(byte[] initiator, byte[] target, long targetAmount, long initiatorAmount, long initiatorSaving, long timestamp) {
 		this(initiator, target, targetAmount, initiatorAmount, initiatorSaving, timestamp, null, null, null, null);
 	}
 
@@ -124,15 +123,15 @@ public class TradeData {
 		return this.target;
 	}
 
-	public BigDecimal getTargetAmount() {
+	public long getTargetAmount() {
 		return this.targetAmount;
 	}
 
-	public BigDecimal getInitiatorAmount() {
+	public long getInitiatorAmount() {
 		return this.initiatorAmount;
 	}
 
-	public BigDecimal getInitiatorSaving() {
+	public long getInitiatorSaving() {
 		return this.initiatorSaving;
 	}
 

src/main/java/org/qortal/data/at/ATData.java

@@ -1,7 +1,11 @@
 package org.qortal.data.at;
 
-import java.math.BigDecimal;
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
 
+// All properties to be converted to JSON via JAXB
+@XmlAccessorType(XmlAccessType.FIELD)
 public class ATData {
 
 	// Properties
@@ -11,23 +15,30 @@ public class ATData {
 	private int version;
 	private long assetId;
 	private byte[] codeBytes;
+	private byte[] codeHash;
 	private boolean isSleeping;
 	private Integer sleepUntilHeight;
 	private boolean isFinished;
 	private boolean hadFatalError;
 	private boolean isFrozen;
-	private BigDecimal frozenBalance;
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private Long frozenBalance;
 
 	// Constructors
 
-	public ATData(String ATAddress, byte[] creatorPublicKey, long creation, int version, long assetId, byte[] codeBytes, boolean isSleeping,
-			Integer sleepUntilHeight, boolean isFinished, boolean hadFatalError, boolean isFrozen, BigDecimal frozenBalance) {
+	// necessary for JAXB serialization
+	protected ATData() {
+	}
+
+	public ATData(String ATAddress, byte[] creatorPublicKey, long creation, int version, long assetId, byte[] codeBytes, byte[] codeHash,
+			boolean isSleeping, Integer sleepUntilHeight, boolean isFinished, boolean hadFatalError, boolean isFrozen, Long frozenBalance) {
 		this.ATAddress = ATAddress;
 		this.creatorPublicKey = creatorPublicKey;
 		this.creation = creation;
 		this.version = version;
 		this.assetId = assetId;
 		this.codeBytes = codeBytes;
+		this.codeHash = codeHash;
 		this.isSleeping = isSleeping;
 		this.sleepUntilHeight = sleepUntilHeight;
 		this.isFinished = isFinished;
@@ -36,14 +47,12 @@ public class ATData {
 		this.frozenBalance = frozenBalance;
 	}
 
-	public ATData(String ATAddress, byte[] creatorPublicKey, long creation, int version, long assetId, byte[] codeBytes, boolean isSleeping,
-			Integer sleepUntilHeight, boolean isFinished, boolean hadFatalError, boolean isFrozen, Long frozenBalance) {
-		this(ATAddress, creatorPublicKey, creation, version, assetId, codeBytes, isSleeping, sleepUntilHeight, isFinished, hadFatalError, isFrozen,
-				(BigDecimal) null);
-
-		// Convert Long frozenBalance to BigDecimal
-		if (frozenBalance != null)
-			this.frozenBalance = BigDecimal.valueOf(frozenBalance, 8);
+	/** For constructing skeleton ATData with bare minimum info. */
+	public ATData(String ATAddress, byte[] creatorPublicKey, long creation, long assetId) {
+		this.ATAddress = ATAddress;
+		this.creatorPublicKey = creatorPublicKey;
+		this.creation = creation;
+		this.assetId = assetId;
 	}
 
 	// Getters / setters
@@ -72,6 +81,10 @@ public class ATData {
 		return this.codeBytes;
 	}
 
+	public byte[] getCodeHash() {
+		return this.codeHash;
+	}
+
 	public boolean getIsSleeping() {
 		return this.isSleeping;
 	}
@@ -112,11 +125,11 @@ public class ATData {
 		this.isFrozen = isFrozen;
 	}
 
-	public BigDecimal getFrozenBalance() {
+	public Long getFrozenBalance() {
 		return this.frozenBalance;
 	}
 
-	public void setFrozenBalance(BigDecimal frozenBalance) {
+	public void setFrozenBalance(Long frozenBalance) {
 		this.frozenBalance = frozenBalance;
 	}
 

src/main/java/org/qortal/data/at/ATStateData.java

@@ -1,7 +1,5 @@
 package org.qortal.data.at;
 
-import java.math.BigDecimal;
-
 public class ATStateData {
 
 	// Properties
@@ -10,33 +8,39 @@ public class ATStateData {
 	private Long creation;
 	private byte[] stateData;
 	private byte[] stateHash;
-	private BigDecimal fees;
+	private Long fees;
+	private boolean isInitial;
 
 	// Constructors
 
 	/** Create new ATStateData */
-	public ATStateData(String ATAddress, Integer height, Long creation, byte[] stateData, byte[] stateHash, BigDecimal fees) {
+	public ATStateData(String ATAddress, Integer height, Long creation, byte[] stateData, byte[] stateHash, Long fees, boolean isInitial) {
 		this.ATAddress = ATAddress;
 		this.height = height;
 		this.creation = creation;
 		this.stateData = stateData;
 		this.stateHash = stateHash;
 		this.fees = fees;
+		this.isInitial = isInitial;
 	}
 
 	/** For recreating per-block ATStateData from repository where not all info is needed */
-	public ATStateData(String ATAddress, int height, byte[] stateHash, BigDecimal fees) {
-		this(ATAddress, height, null, null, stateHash, fees);
+	public ATStateData(String ATAddress, int height, byte[] stateHash, Long fees, boolean isInitial) {
+		this(ATAddress, height, null, null, stateHash, fees, isInitial);
 	}
 
 	/** For creating ATStateData from serialized bytes when we don't have all the info */
 	public ATStateData(String ATAddress, byte[] stateHash) {
-		this(ATAddress, null, null, null, stateHash, null);
+		// This won't ever be initial AT state from deployment as that's never serialized over the network,
+		// but generated when the DeployAtTransaction is processed locally.
+		this(ATAddress, null, null, null, stateHash, null, false);
 	}
 
 	/** For creating ATStateData from serialized bytes when we don't have all the info */
-	public ATStateData(String ATAddress, byte[] stateHash, BigDecimal fees) {
-		this(ATAddress, null, null, null, stateHash, fees);
+	public ATStateData(String ATAddress, byte[] stateHash, Long fees) {
+		// This won't ever be initial AT state from deployment as that's never serialized over the network,
+		// but generated when the DeployAtTransaction is processed locally.
+		this(ATAddress, null, null, null, stateHash, fees, false);
 	}
 
 	// Getters / setters
@@ -66,8 +70,12 @@ public class ATStateData {
 		return this.stateHash;
 	}
 
-	public BigDecimal getFees() {
+	public Long getFees() {
 		return this.fees;
 	}
 
+	public boolean isInitial() {
+		return this.isInitial;
+	}
+
 }

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

@@ -3,11 +3,11 @@ package org.qortal.data.block;
 import com.google.common.primitives.Bytes;
 
 import java.io.Serializable;
-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.adapters.XmlJavaTypeAdapter;
 
 import org.qortal.crypto.Crypto;
 
@@ -23,14 +23,20 @@ public class BlockData implements Serializable {
 	private int version;
 	private byte[] reference;
 	private int transactionCount;
-	private BigDecimal totalFees;
+
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long totalFees;
+
 	private byte[] transactionsSignature;
 	private Integer height;
 	private long timestamp;
 	private byte[] minterPublicKey;
 	private byte[] minterSignature;
 	private int atCount;
-	private BigDecimal atFees;
+
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private long atFees;
+
 	private byte[] encodedOnlineAccounts;
 	private int onlineAccountsCount;
 	private Long onlineAccountsTimestamp;
@@ -42,8 +48,8 @@ public class BlockData implements Serializable {
 	protected BlockData() {
 	}
 
-	public BlockData(int version, byte[] reference, int transactionCount, BigDecimal totalFees, byte[] transactionsSignature, Integer height, long timestamp,
-			byte[] minterPublicKey, byte[] minterSignature, int atCount, BigDecimal atFees,
+	public BlockData(int version, byte[] reference, int transactionCount, long totalFees, byte[] transactionsSignature, Integer height, long timestamp,
+			byte[] minterPublicKey, byte[] minterSignature, int atCount, long atFees,
 			byte[] encodedOnlineAccounts, int onlineAccountsCount, Long onlineAccountsTimestamp, byte[] onlineAccountsSignatures) {
 		this.version = version;
 		this.reference = reference;
@@ -67,8 +73,8 @@ public class BlockData implements Serializable {
 			this.signature = null;
 	}
 
-	public BlockData(int version, byte[] reference, int transactionCount, BigDecimal totalFees, byte[] transactionsSignature, Integer height, long timestamp,
-			byte[] minterPublicKey, byte[] minterSignature, int atCount, BigDecimal atFees) {
+	public BlockData(int version, byte[] reference, int transactionCount, long totalFees, byte[] transactionsSignature, Integer height, long timestamp,
+			byte[] minterPublicKey, byte[] minterSignature, int atCount, long atFees) {
 		this(version, reference, transactionCount, totalFees, transactionsSignature, height, timestamp, minterPublicKey, minterSignature, atCount, atFees,
 				null, 0, null, null);
 	}
@@ -103,11 +109,11 @@ public class BlockData implements Serializable {
 		this.transactionCount = transactionCount;
 	}
 
-	public BigDecimal getTotalFees() {
+	public long getTotalFees() {
 		return this.totalFees;
 	}
 
-	public void setTotalFees(BigDecimal totalFees) {
+	public void setTotalFees(long totalFees) {
 		this.totalFees = totalFees;
 	}
 
@@ -151,11 +157,11 @@ public class BlockData implements Serializable {
 		this.atCount = atCount;
 	}
 
-	public BigDecimal getATFees() {
+	public long getATFees() {
 		return this.atFees;
 	}
 
-	public void setATFees(BigDecimal atFees) {
+	public void setATFees(long atFees) {
 		this.atFees = atFees;
 	}
 

src/main/java/org/qortal/data/chat/ActiveChats.java

@@ -0,0 +1,121 @@
+package org.qortal.data.chat;
+
+import java.util.List;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+
+@XmlAccessorType(XmlAccessType.FIELD)
+public class ActiveChats {
+
+	@XmlAccessorType(XmlAccessType.FIELD)
+	public static class GroupChat {
+		private int groupId;
+		private String groupName;
+
+		// The following fields might not be present for groupId 0
+		private Long timestamp;
+		private String sender;
+		private String senderName;
+
+		protected GroupChat() {
+			/* JAXB */
+		}
+
+		public GroupChat(int groupId, String groupName, Long timestamp, String sender, String senderName) {
+			this.groupId = groupId;
+			this.groupName = groupName;
+			this.timestamp = timestamp;
+			this.sender = sender;
+			this.senderName = senderName;
+		}
+
+		public int getGroupId() {
+			return this.groupId;
+		}
+
+		public String getGroupName() {
+			return this.groupName;
+		}
+
+		public Long getTimestamp() {
+			return this.timestamp;
+		}
+
+		public String getSender() {
+			return this.sender;
+		}
+
+		public String getSenderName() {
+			return this.senderName;
+		}
+	}
+
+	@XmlAccessorType(XmlAccessType.FIELD)
+	public static class DirectChat {
+		private String address;
+		private String name;
+		private long timestamp;
+		private String sender;
+		private String senderName;
+
+		protected DirectChat() {
+			/* JAXB */
+		}
+
+		public DirectChat(String address, String name, long timestamp, String sender, String senderName) {
+			this.address = address;
+			this.name = name;
+			this.timestamp = timestamp;
+			this.sender = sender;
+			this.senderName = senderName;
+		}
+
+		public String getAddress() {
+			return this.address;
+		}
+
+		public String getName() {
+			return this.name;
+		}
+
+		public long getTimestamp() {
+			return this.timestamp;
+		}
+
+		public String getSender() {
+			return this.sender;
+		}
+
+		public String getSenderName() {
+			return this.senderName;
+		}
+	}
+
+	// Properties
+
+	private List<GroupChat> groups;
+
+	private List<DirectChat> direct;
+
+	// Constructors
+
+	protected ActiveChats() {
+		/* For JAXB */
+	}
+
+	// For repository use
+	public ActiveChats(List<GroupChat> groups, List<DirectChat> direct) {
+		this.groups = groups;
+		this.direct = direct;
+	}
+
+	public List<GroupChat> getGroups() {
+		return this.groups;
+	}
+
+	public List<DirectChat> getDirect() {
+		return this.direct;
+	}
+
+}

src/main/java/org/qortal/data/chat/ChatMessage.java

@@ -0,0 +1,109 @@
+package org.qortal.data.chat;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+
+@XmlAccessorType(XmlAccessType.FIELD)
+public class ChatMessage {
+
+	// Properties
+
+	private long timestamp;
+
+	private int txGroupId;
+
+	private byte[] reference;
+
+	private byte[] senderPublicKey;
+
+	/* Address of sender */
+	private String sender;
+
+	// Not always present
+	private String senderName;
+
+	/* Address of recipient (if any) */
+	private String recipient; // can be null
+
+	private String recipientName;
+
+	private byte[] data;
+
+	private boolean isText;
+	private boolean isEncrypted;
+
+	private byte[] signature;
+
+	// Constructors
+
+	protected ChatMessage() {
+		/* For JAXB */
+	}
+
+	// For repository use
+	public ChatMessage(long timestamp, int txGroupId, byte[] reference, byte[] senderPublicKey, String sender,
+			String senderName, String recipient, String recipientName, byte[] data, boolean isText,
+			boolean isEncrypted, byte[] signature) {
+		this.timestamp = timestamp;
+		this.txGroupId = txGroupId;
+		this.reference = reference;
+		this.senderPublicKey = senderPublicKey;
+		this.sender = sender;
+		this.senderName = senderName;
+		this.recipient = recipient;
+		this.recipientName = recipientName;
+		this.data = data;
+		this.isText = isText;
+		this.isEncrypted = isEncrypted;
+		this.signature = signature;
+	}
+
+	public long getTimestamp() {
+		return this.timestamp;
+	}
+
+	public int getTxGroupId() {
+		return this.txGroupId;
+	}
+
+	public byte[] getReference() {
+		return this.reference;
+	}
+
+	public byte[] getSenderPublicKey() {
+		return this.senderPublicKey;
+	}
+
+	public String getSender() {
+		return this.sender;
+	}
+
+	public String getSenderName() {
+		return this.senderName;
+	}
+
+	public String getRecipient() {
+		return this.recipient;
+	}
+
+	public String getRecipientName() {
+		return this.recipientName;
+	}
+
+	public byte[] getData() {
+		return this.data;
+	}
+
+	public boolean isText() {
+		return this.isText;
+	}
+
+	public boolean isEncrypted() {
+		return this.isEncrypted;
+	}
+
+	public byte[] getSignature() {
+		return this.signature;
+	}
+
+}

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

@@ -0,0 +1,68 @@
+package org.qortal.data.crosschain;
+
+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;
+
+// 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")
+	public String qortalAtAddress;
+
+	@Schema(description = "AT creator's Qortal address")
+	public String qortalCreator;
+
+	@Schema(description = "Timestamp when AT was created (milliseconds since epoch)")
+	public long creationTimestamp;
+
+	@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 = "Initial QORT payment that will be sent to Qortal trade partner")
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	public long initialPayout;
+
+	@Schema(description = "Final QORT payment that will be sent to Qortal trade partner")
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	public long redeemPayout;
+
+	@Schema(description = "Trade partner's Qortal address (trade begins when this is set)")
+	public String qortalRecipient;
+
+	@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 = "Actual Qortal block height when AT will automatically refund to AT creator (after trade begins)")
+	public Integer tradeRefundHeight;
+
+	@Schema(description = "Amount, in BTC, that AT creator expects Bitcoin P2SH to pay out (excluding miner fees)")
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	public long expectedBitcoin;
+
+	public Mode mode;
+
+	@Schema(description = "Suggested Bitcoin P2SH nLockTime based on trade timeout")
+	public Integer lockTime;
+
+	// Constructors
+
+	// Necessary for JAXB
+	public CrossChainTradeData() {
+	}
+
+}

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

@@ -23,18 +23,26 @@ public class GroupData {
 	private ApprovalThreshold approvalThreshold;
 	private int minimumBlockDelay;
 	private int maximumBlockDelay;
+
 	/** Reference to CREATE_GROUP or UPDATE_GROUP transaction, used to rebuild group during orphaning. */
 	// No need to ever expose this via API
 	@XmlTransient
 	@Schema(hidden = true)
 	private byte[] reference;
+
 	// For internal use
 	@XmlTransient
-	@Schema(
-		hidden = true
-	)
+	@Schema(hidden = true)
 	private int creationGroupId;
 
+	// For internal use
+	@XmlTransient
+	@Schema(hidden = true)
+	private String reducedGroupName;
+
+	// We abuse GroupData for API purposes by adding this unrelated field. Not always present.
+	private Boolean isAdmin;
+
 	// Constructors
 
 	// necessary for JAX-RS serialization
@@ -42,10 +50,12 @@ public class GroupData {
 	}
 
 	/** Constructs new GroupData with nullable groupId and nullable updated [timestamp] */
-	public GroupData(Integer groupId, String owner, String name, String description, long created, Long updated, boolean isOpen, ApprovalThreshold approvalThreshold, int minBlockDelay, int maxBlockDelay, byte[] reference, int creationGroupId) {
+	public GroupData(Integer groupId, String owner, String groupName, String description, long created, Long updated,
+			boolean isOpen, ApprovalThreshold approvalThreshold, int minBlockDelay, int maxBlockDelay, byte[] reference,
+			int creationGroupId, String reducedGroupName) {
 		this.groupId = groupId;
 		this.owner = owner;
-		this.groupName = name;
+		this.groupName = groupName;
 		this.description = description;
 		this.created = created;
 		this.updated = updated;
@@ -55,11 +65,15 @@ public class GroupData {
 		this.minimumBlockDelay = minBlockDelay;
 		this.maximumBlockDelay = maxBlockDelay;
 		this.creationGroupId = creationGroupId;
+		this.reducedGroupName = reducedGroupName;
 	}
 
 	/** Constructs new GroupData with unassigned groupId */
-	public GroupData(String owner, String name, String description, long created, boolean isOpen, ApprovalThreshold approvalThreshold, int minBlockDelay, int maxBlockDelay, byte[] reference, int creationGroupId) {
-		this(null, owner, name, description, created, null, isOpen, approvalThreshold, minBlockDelay, maxBlockDelay, reference, creationGroupId);
+	public GroupData(String owner, String groupName, String description, long created, boolean isOpen,
+			ApprovalThreshold approvalThreshold, int minBlockDelay, int maxBlockDelay, byte[] reference,
+			int creationGroupId, String reducedGroupName) {
+		this(null, owner, groupName, description, created, null, isOpen, approvalThreshold, minBlockDelay,
+				maxBlockDelay, reference, creationGroupId, reducedGroupName);
 	}
 
 	// Getters / setters
@@ -112,7 +126,7 @@ public class GroupData {
 		this.reference = reference;
 	}
 
-	public boolean getIsOpen() {
+	public boolean isOpen() {
 		return this.isOpen;
 	}
 
@@ -140,4 +154,22 @@ public class GroupData {
 		return this.creationGroupId;
 	}
 
+	public String getReducedGroupName() {
+		return this.reducedGroupName;
+	}
+
+	public void setReducedGroupName(String reducedGroupName) {
+		this.reducedGroupName = reducedGroupName;
+	}
+
+	// This is for API call GET /groups/member/{address}
+
+	public Boolean isAdmin() {
+		return this.isAdmin;
+	}
+
+	public void setIsAdmin(boolean isAdmin) {
+		this.isAdmin = isAdmin;
+	}
+
 }

src/main/java/org/qortal/data/naming/NameData.java

@@ -1,10 +1,9 @@
 package org.qortal.data.naming;
 
-import java.math.BigDecimal;
-
 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;
 
@@ -13,36 +12,47 @@ import io.swagger.v3.oas.annotations.media.Schema;
 public class NameData {
 
 	// Properties
-	private String owner;
+
 	private String name;
+
+	private String reducedName;
+
+	private String owner;
+
 	private String data;
+
 	private long registered;
-	private Long updated;
-	// No need to expose this via API
-	@XmlTransient
-	@Schema(
-		hidden = true
-	)
-	private byte[] reference;
+
+	private Long updated; // Not always present
+
 	private boolean isForSale;
-	private BigDecimal salePrice;
+
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private Long salePrice;
+
+	// For internal use - no need to expose this via API
+	@XmlTransient
+	@Schema(hidden = true)
+	private byte[] reference;
+
 	// For internal use
 	@XmlTransient
-	@Schema(
-		hidden = true
-	)
+	@Schema(hidden = true)
 	private int creationGroupId;
 
 	// Constructors
 
-	// necessary for JAX-RS serialization
+	// necessary for JAXB
 	protected NameData() {
 	}
 
-	public NameData(String owner, String name, String data, long registered, Long updated, byte[] reference, boolean isForSale, BigDecimal salePrice,
-			int creationGroupId) {
-		this.owner = owner;
+	// Typically used when fetching from repository
+	public NameData(String name, String reducedName, String owner, String data, long registered,
+			Long updated, boolean isForSale, Long salePrice,
+			byte[] reference, int creationGroupId) {
 		this.name = name;
+		this.reducedName = reducedName;
+		this.owner = owner;
 		this.data = data;
 		this.registered = registered;
 		this.updated = updated;
@@ -52,12 +62,29 @@ public class NameData {
 		this.creationGroupId = creationGroupId;
 	}
 
-	public NameData(String owner, String name, String data, long registered, byte[] reference, int creationGroupId) {
-		this(owner, name, data, registered, null, reference, false, null, creationGroupId);
+	// Typically used when registering a new name
+	public NameData(String name, String reducedName, String owner, String data, long registered, byte[] reference, int creationGroupId) {
+		this(name, reducedName, owner, data, registered, null, false, null, reference, creationGroupId);
 	}
 
 	// Getters / setters
 
+	public String getName() {
+		return this.name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public String getReducedName() {
+		return this.reducedName;
+	}
+
+	public void setReducedName(String reducedName) {
+		this.reducedName = reducedName;
+	}
+
 	public String getOwner() {
 		return this.owner;
 	}
@@ -66,10 +93,6 @@ public class NameData {
 		this.owner = owner;
 	}
 
-	public String getName() {
-		return this.name;
-	}
-
 	public String getData() {
 		return this.data;
 	}
@@ -90,6 +113,22 @@ public class NameData {
 		this.updated = updated;
 	}
 
+	public boolean isForSale() {
+		return this.isForSale;
+	}
+
+	public void setIsForSale(boolean isForSale) {
+		this.isForSale = isForSale;
+	}
+
+	public Long getSalePrice() {
+		return this.salePrice;
+	}
+
+	public void setSalePrice(Long salePrice) {
+		this.salePrice = salePrice;
+	}
+
 	public byte[] getReference() {
 		return this.reference;
 	}
@@ -98,22 +137,6 @@ public class NameData {
 		this.reference = reference;
 	}
 
-	public boolean getIsForSale() {
-		return this.isForSale;
-	}
-
-	public void setIsForSale(boolean isForSale) {
-		this.isForSale = isForSale;
-	}
-
-	public BigDecimal getSalePrice() {
-		return this.salePrice;
-	}
-
-	public void setSalePrice(BigDecimal salePrice) {
-		this.salePrice = salePrice;
-	}
-
 	public int getCreationGroupId() {
 		return this.creationGroupId;
 	}

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

@@ -1,5 +1,7 @@
 package org.qortal.data.network;
 
+import java.util.Arrays;
+
 import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
 import javax.xml.bind.annotation.XmlElement;
@@ -44,4 +46,36 @@ public class OnlineAccountData {
 		return new PublicKeyAccount(null, this.publicKey).getAddress();
 	}
 
+	// Comparison
+
+	@Override
+	public boolean equals(Object other) {
+		if (other == this)
+			return true;
+
+		if (!(other instanceof OnlineAccountData))
+			return false;
+
+		OnlineAccountData otherOnlineAccountData = (OnlineAccountData) other;
+
+		// Very quick comparison
+		if (otherOnlineAccountData.timestamp != this.timestamp)
+			return false;
+
+		// Signature more likely to be unique than public key
+		if (!Arrays.equals(otherOnlineAccountData.signature, this.signature))
+			return false;
+
+		if (!Arrays.equals(otherOnlineAccountData.publicKey, this.publicKey))
+			return false;
+
+		return true;
+	}
+
+	@Override
+	public int hashCode() {
+		// Pretty lazy implementation
+		return (int) this.timestamp;
+	}
+
 }

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

@@ -1,12 +1,12 @@
 package org.qortal.data.transaction;
 
-import java.math.BigDecimal;
 
 import javax.xml.bind.Unmarshaller;
 import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
+import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
 
-import org.qortal.account.GenesisAccount;
+import org.qortal.account.NullAccount;
 import org.qortal.transaction.Transaction.TransactionType;
 
 import io.swagger.v3.oas.annotations.media.Schema;
@@ -17,10 +17,19 @@ import io.swagger.v3.oas.annotations.media.Schema;
 public class ATTransactionData extends TransactionData {
 
 	// Properties
+
 	private String atAddress;
+
 	private String recipient;
-	private BigDecimal amount;
+
+	// Not always present
+	@XmlJavaTypeAdapter(value = org.qortal.api.AmountTypeAdapter.class)
+	private Long amount;
+
+	// Not always present
 	private Long assetId;
+
+	// Not always present
 	private byte[] message;
 
 	// Constructors
@@ -31,14 +40,14 @@ public class ATTransactionData extends TransactionData {
 	}
 
 	public void afterUnmarshal(Unmarshaller u, Object parent) {
-		this.creatorPublicKey = GenesisAccount.PUBLIC_KEY;
+		this.creatorPublicKey = NullAccount.PUBLIC_KEY;
 	}
 
-	/** From repository */
-	public ATTransactionData(BaseTransactionData baseTransactionData, String atAddress, String recipient, BigDecimal amount, Long assetId, byte[] message) {
+	/** Constructing from repository */
+	public ATTransactionData(BaseTransactionData baseTransactionData, String atAddress, String recipient, Long amount, Long assetId, byte[] message) {
 		super(TransactionType.AT, baseTransactionData);
 
-		this.creatorPublicKey = GenesisAccount.PUBLIC_KEY;
+		this.creatorPublicKey = NullAccount.PUBLIC_KEY;
 		this.atAddress = atAddress;
 		this.recipient = recipient;
 		this.amount = amount;
@@ -46,6 +55,16 @@ public class ATTransactionData extends TransactionData {
 		this.message = message;
 	}
 
+	/** Constructing a new MESSAGE-type AT transaction */
+	public ATTransactionData(BaseTransactionData baseTransactionData, String atAddress, String recipient, byte[] message) {
+		this(baseTransactionData, atAddress, recipient, null, null, message);
+	}
+
+	/** Constructing a new PAYMENT-type AT transaction */
+	public ATTransactionData(BaseTransactionData baseTransactionData, String atAddress, String recipient, long amount, long assetId) {
+		this(baseTransactionData, atAddress, recipient, amount, assetId, null);
+	}
+
 	// Getters/Setters
 
 	public String getATAddress() {
@@ -56,7 +75,7 @@ public class ATTransactionData extends TransactionData {
 		return this.recipient;
 	}
 
-	public BigDecimal getAmount() {
+	public Long getAmount() {
 		return this.amount;
 	}
 

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

@@ -6,7 +6,7 @@ import javax.xml.bind.annotation.XmlAccessorType;
 import javax.xml.bind.annotation.XmlElement;
 
 import org.eclipse.persistence.oxm.annotations.XmlDiscriminatorValue;
-import org.qortal.account.GenesisAccount;
+import org.qortal.account.NullAccount;
 import org.qortal.block.GenesisBlock;
 import org.qortal.transaction.Transaction.TransactionType;
 
@@ -36,10 +36,10 @@ public class AccountFlagsTransactionData extends TransactionData {
 		/*
 		 *  If we're being constructed as part of the genesis block info inside blockchain config
 		 *  and no specific creator's public key is supplied
-		 *  then use genesis account's public key.
+		 *  then use null account's public key.
 		 */
 		if (parent instanceof GenesisBlock.GenesisInfo && this.creatorPublicKey == null)
-			this.creatorPublicKey = GenesisAccount.PUBLIC_KEY;
+			this.creatorPublicKey = NullAccount.PUBLIC_KEY;
 	}
 
 	/** From repository */

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

@@ -6,7 +6,7 @@ import javax.xml.bind.annotation.XmlAccessorType;
 import javax.xml.bind.annotation.XmlElement;
 
 import org.eclipse.persistence.oxm.annotations.XmlDiscriminatorValue;
-import org.qortal.account.GenesisAccount;
+import org.qortal.account.NullAccount;
 import org.qortal.block.GenesisBlock;
 import org.qortal.transaction.Transaction.TransactionType;
 
@@ -33,10 +33,10 @@ public class AccountLevelTransactionData extends TransactionData {
 		/*
 		 *  If we're being constructed as part of the genesis block info inside blockchain config
 		 *  and no specific creator's public key is supplied
-		 *  then use genesis account's public key.
+		 *  then use null account's public key.
 		 */
 		if (parent instanceof GenesisBlock.GenesisInfo && this.creatorPublicKey == null)
-			this.creatorPublicKey = GenesisAccount.PUBLIC_KEY;
+			this.creatorPublicKey = NullAccount.PUBLIC_KEY;
 	}
 
 	/** From repository, network/API */