Use WhisperSystems Curve25519 library.

Note: Curve25519 is tested using standard ECDH and ECDHC over the Curve25519 curve.

.gitlab-ci.yml

@@ -6,8 +6,18 @@ cache:
     - .gradle/caches
 
 before_script:
+  - set -e
   - export GRADLE_USER_HOME=$PWD/.gradle
-  - echo y | /opt/android-sdk/tools/bin/sdkmanager "build-tools;23.0.3"
+  # Accept the license for the Android build tools
+  - echo y | /opt/android-sdk/tools/bin/sdkmanager "build-tools;26.0.2"
+  # Download OpenJDK 6 so we can compile against its standard library
+  - JDK_FILE=openjdk-6-jre-headless_6b38-1.13.10-1~deb7u1_amd64.deb
+  - if [ ! -d openjdk ]
+  - then
+  - wget -q http://ftp.uk.debian.org/debian/pool/main/o/openjdk-6/$JDK_FILE
+  - dpkg-deb -x $JDK_FILE openjdk
+  - fi
+  - export JAVA_6_HOME=$PWD/openjdk/usr/lib/jvm/java-6-openjdk-amd64
 
 test:
   script:

bramble-android/build.gradle

@@ -6,99 +6,91 @@ apply plugin: 'witness'
 apply plugin: 'de.undercouch.download'
 
 android {
-	compileSdkVersion 23
+	compileSdkVersion 27
-	buildToolsVersion "23.0.3"
+	buildToolsVersion '26.0.2'
 
 	defaultConfig {
 		minSdkVersion 14
-		targetSdkVersion 22
+		targetSdkVersion 26
-		versionCode 1611
+		versionCode 1700
-		versionName "0.16.11"
+		versionName "0.17.0"
 		consumerProguardFiles 'proguard-rules.txt'
 	}
 
 	compileOptions {
-		sourceCompatibility JavaVersion.VERSION_1_7
+		sourceCompatibility JavaVersion.VERSION_1_8
-		targetCompatibility JavaVersion.VERSION_1_7
+		targetCompatibility JavaVersion.VERSION_1_8
 	}
 }
 
 dependencies {
-	compile project(':bramble-core')
+	implementation project(path: ':bramble-core', configuration: 'default')
-	compile fileTree(dir: 'libs', include: '*.jar')
+	implementation fileTree(dir: 'libs', include: '*.jar')
-	provided 'javax.annotation:jsr250-api:1.0'
+
+	annotationProcessor 'com.google.dagger:dagger-compiler:2.0.2'
+
+	compileOnly 'javax.annotation:jsr250-api:1.0'
 }
 
-def torBinaryDir = 'src/main/res/raw'
+dependencyVerification {
-
+	verify = [
-task downloadTorGeoIp(type: Download) {
+			'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
-	src 'https://briarproject.org/build/geoip-2017-09-06.zip'
+			'com.google.dagger:dagger-compiler:2.0.2:dagger-compiler-2.0.2.jar:b74bc9de063dd4c6400b232231f2ef5056145b8fbecbf5382012007dd1c071b3',
-	dest "$torBinaryDir/geoip.zip"
+			'com.google.dagger:dagger-producers:2.0-beta:dagger-producers-2.0-beta.jar:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
-	onlyIfNewer true
+			'com.google.dagger:dagger:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
+			'com.google.guava:guava:18.0:guava-18.0.jar:d664fbfc03d2e5ce9cab2a44fb01f1d0bf9dfebeccc1a473b1f9ea31f79f6f99',
+			'com.h2database:h2:1.4.192:h2-1.4.192.jar:225b22e9857235c46c93861410b60b8c81c10dc8985f4faf188985ba5445126c',
+			'com.madgag.spongycastle:core:1.58.0.0:core-1.58.0.0.jar:199617dd5698c5a9312b898c0a4cec7ce9dd8649d07f65d91629f58229d72728',
+			'javax.annotation:jsr250-api:1.0:jsr250-api-1.0.jar:a1a922d0d9b6d183ed3800dfac01d1e1eb159f0e8c6f94736931c1def54a941f',
+			'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
+			'net.i2p.crypto:eddsa:0.2.0:eddsa-0.2.0.jar:a7cb1b85c16e2f0730b9204106929a1d9aaae1df728adc7041a8b8b605692140',
+			'org.bitlet:weupnp:0.1.4:weupnp-0.1.4.jar:88df7e6504929d00bdb832863761385c68ab92af945b04f0770b126270a444fb',
+			'org.jacoco:org.jacoco.agent:0.7.4.201502262128:org.jacoco.agent-0.7.4.201502262128-runtime.jar:e357a0f1d573c2f702a273992b1b6cb661734f66311854efb3778a888515c5b5',
+			'org.jacoco:org.jacoco.agent:0.7.4.201502262128:org.jacoco.agent-0.7.4.201502262128.jar:47b4bec6df11a1118da3953da8b9fa1e7079d6fec857faa1a3cf912e53a6fd4e',
+			'org.jacoco:org.jacoco.ant:0.7.4.201502262128:org.jacoco.ant-0.7.4.201502262128.jar:013ce2a68ba57a3c59215ae0dec4df3498c078062a38c3b94c841fc14450f283',
+			'org.jacoco:org.jacoco.core:0.7.4.201502262128:org.jacoco.core-0.7.4.201502262128.jar:ec4c74554312fac5116350164786f91b35c9e082fa4ea598bfa42b5db05d7abb',
+			'org.jacoco:org.jacoco.report:0.7.4.201502262128:org.jacoco.report-0.7.4.201502262128.jar:7a3554c605e088e7e323b1084656243f0444fa353e2f2dee1f1a4204eb64ff09',
+			'org.ow2.asm:asm-debug-all:5.0.1:asm-debug-all-5.0.1.jar:4734de5b515a454b0096db6971fb068e5f70e6f10bbee2b3bd2fdfe5d978ed57',
+	]
 }
 
-task downloadTorBinaryArm(type: Download) {
+ext.torBinaryDir = 'src/main/res/raw'
-	src 'https://briarproject.org/build/tor-0.2.9.12-arm.zip'
+ext.torVersion = '0.2.9.12'
-	dest "$torBinaryDir/tor_arm.zip"
+ext.geoipVersion = '2017-09-06'
-	onlyIfNewer true
+ext.torDownloadUrl = 'https://briarproject.org/build/'
+
+def torBinaries = [
+		"tor_arm"    : '8ed0b347ffed1d6a4d2fd14495118eb92be83e9cc06e057e15220dc288b31688',
+		"tor_arm_pie": '64403262511c29f462ca5e7c7621bfc3c944898364d1d5ad35a016bb8a034283',
+		"tor_x86"    : '61e014607a2079bcf1646289c67bff6372b1aded6e1d8d83d7791efda9a4d5ab',
+		"tor_x86_pie": '18fbc98356697dd0895836ab46d5c9877d1c539193464f7db1e82a65adaaf288',
+		"geoip"      : 'fe49d3adb86d3c512373101422a017dbb86c85a570524663f09dd8ce143a24f3'
+]
+
+def downloadBinary(name) {
+	return tasks.create("downloadBinary${name}", Download) {
+		src "${torDownloadUrl}${name}.zip"
+				.replace('tor_', "tor-${torVersion}-")
+				.replace('geoip', "geoip-${geoipVersion}")
+				.replaceAll('_', '-')
+		dest "${torBinaryDir}/${name}.zip"
+		onlyIfNewer true
+	}
 }
 
-task downloadTorBinaryArmPie(type: Download) {
+def verifyBinary(name, chksum) {
-	src 'https://briarproject.org/build/tor-0.2.9.12-arm-pie.zip'
+	return tasks.create([
-	dest "$torBinaryDir/tor_arm_pie.zip"
+			name     : "verifyBinary${name}",
-	onlyIfNewer true
+			type     : Verify,
-}
+			dependsOn: downloadBinary(name)]) {
-
+		src "${torBinaryDir}/${name}.zip"
-task downloadTorBinaryX86(type: Download) {
+		algorithm 'SHA-256'
-	src 'https://briarproject.org/build/tor-0.2.9.12-x86.zip'
+		checksum chksum
-	dest "$torBinaryDir/tor_x86.zip"
+	}
-	onlyIfNewer true
-}
-
-task downloadTorBinaryX86Pie(type: Download) {
-	src 'https://briarproject.org/build/tor-0.2.9.12-x86-pie.zip'
-	dest "$torBinaryDir/tor_x86_pie.zip"
-	onlyIfNewer true
-}
-
-task verifyTorGeoIp(type: Verify, dependsOn: 'downloadTorGeoIp') {
-	src "$torBinaryDir/geoip.zip"
-	algorithm 'SHA-256'
-	checksum 'fe49d3adb86d3c512373101422a017dbb86c85a570524663f09dd8ce143a24f3'
-}
-
-task verifyTorBinaryArm(type: Verify, dependsOn: 'downloadTorBinaryArm') {
-	src "$torBinaryDir/tor_arm.zip"
-	algorithm 'SHA-256'
-	checksum '8ed0b347ffed1d6a4d2fd14495118eb92be83e9cc06e057e15220dc288b31688'
-}
-
-task verifyTorBinaryArmPie(type: Verify, dependsOn: 'downloadTorBinaryArmPie') {
-	src "$torBinaryDir/tor_arm_pie.zip"
-	algorithm 'SHA-256'
-	checksum '64403262511c29f462ca5e7c7621bfc3c944898364d1d5ad35a016bb8a034283'
-}
-
-task verifyTorBinaryX86(type: Verify, dependsOn: 'downloadTorBinaryX86') {
-	src "$torBinaryDir/tor_x86.zip"
-	algorithm 'SHA-256'
-	checksum '61e014607a2079bcf1646289c67bff6372b1aded6e1d8d83d7791efda9a4d5ab'
-}
-
-task verifyTorBinaryX86Pie(type: Verify, dependsOn: 'downloadTorBinaryX86Pie') {
-	src "$torBinaryDir/tor_x86_pie.zip"
-	algorithm 'SHA-256'
-	checksum '18fbc98356697dd0895836ab46d5c9877d1c539193464f7db1e82a65adaaf288'
 }
 
 project.afterEvaluate {
-	preBuild.dependsOn {
+	torBinaries.every { key, value ->
-		[
+		preBuild.dependsOn.add(verifyBinary(key, value))
-				'verifyTorGeoIp',
-				'verifyTorBinaryArm',
-				'verifyTorBinaryArmPie',
-				'verifyTorBinaryX86',
-				'verifyTorBinaryX86Pie'
-		]
 	}
 }

bramble-android/proguard-rules.txt

@@ -8,6 +8,8 @@
 -dontwarn dagger.**
 -dontnote dagger.**
 
+-keep class net.i2p.crypto.eddsa.** { *; }
+
 -dontwarn sun.misc.Unsafe
 -dontnote com.google.common.**
 

bramble-android/src/main/AndroidManifest.xml

@@ -11,8 +11,6 @@
 	<uses-permission android:name="android.permission.INTERNET"/>
 	<uses-permission android:name="android.permission.READ_LOGS"/>
 	<uses-permission android:name="android.permission.WAKE_LOCK"/>
-	<!-- Since API 23, this is needed to add contacts via Bluetooth -->
-	<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
 
 	<application
 		android:allowBackup="false"

bramble-android/src/main/java/org/briarproject/bramble/plugin/AndroidPluginModule.java

@@ -45,7 +45,7 @@ public class AndroidPluginModule {
 				backoffFactory);
 		DuplexPluginFactory lan = new AndroidLanTcpPluginFactory(ioExecutor,
 				backoffFactory, appContext);
-		final Collection<DuplexPluginFactory> duplex =
+		Collection<DuplexPluginFactory> duplex =
 				Arrays.asList(bluetooth, tor, lan);
 		@NotNullByDefault
 		PluginConfig pluginConfig = new PluginConfig() {

bramble-android/src/main/java/org/briarproject/bramble/plugin/droidtooth/DroidtoothPlugin.java

@@ -124,12 +124,7 @@ class DroidtoothPlugin implements DuplexPlugin, EventListener {
 		// with a message queue, so submit it to the AndroidExecutor
 		try {
 			adapter = androidExecutor.runOnBackgroundThread(
-					new Callable<BluetoothAdapter>() {
+					BluetoothAdapter::getDefaultAdapter).get();
-						@Override
-						public BluetoothAdapter call() throws Exception {
-							return BluetoothAdapter.getDefaultAdapter();
-						}
-					}).get();
 		} catch (InterruptedException e) {
 			Thread.currentThread().interrupt();
 			LOG.warning("Interrupted while getting BluetoothAdapter");
@@ -162,40 +157,36 @@ class DroidtoothPlugin implements DuplexPlugin, EventListener {
 	}
 
 	private void bind() {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(() -> {
-			@Override
+			if (!isRunning()) return;
-			public void run() {
+			String address = AndroidUtils.getBluetoothAddress(appContext,
-				if (!isRunning()) return;
+					adapter);
-				String address = AndroidUtils.getBluetoothAddress(appContext,
+			if (LOG.isLoggable(INFO))
-						adapter);
+				LOG.info("Local address " + scrubMacAddress(address));
-				if (LOG.isLoggable(INFO))
+			if (!StringUtils.isNullOrEmpty(address)) {
-					LOG.info("Local address " + scrubMacAddress(address));
+				// Advertise the Bluetooth address to contacts
-				if (!StringUtils.isNullOrEmpty(address)) {
+				TransportProperties p = new TransportProperties();
-					// Advertise the Bluetooth address to contacts
+				p.put(PROP_ADDRESS, address);
-					TransportProperties p = new TransportProperties();
+				callback.mergeLocalProperties(p);
-					p.put(PROP_ADDRESS, address);
-					callback.mergeLocalProperties(p);
-				}
-				// Bind a server socket to accept connections from contacts
-				BluetoothServerSocket ss;
-				try {
-					ss = adapter.listenUsingInsecureRfcommWithServiceRecord(
-							"RFCOMM", getUuid());
-				} catch (IOException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
-					return;
-				}
-				if (!isRunning()) {
-					tryToClose(ss);
-					return;
-				}
-				LOG.info("Socket bound");
-				socket = ss;
-				backoff.reset();
-				callback.transportEnabled();
-				acceptContactConnections();
 			}
+			// Bind a server socket to accept connections from contacts
+			BluetoothServerSocket ss;
+			try {
+				ss = adapter.listenUsingInsecureRfcommWithServiceRecord(
+						"RFCOMM", getUuid());
+			} catch (IOException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+				return;
+			}
+			if (!isRunning()) {
+				tryToClose(ss);
+				return;
+			}
+			LOG.info("Socket bound");
+			socket = ss;
+			backoff.reset();
+			callback.transportEnabled();
+			acceptContactConnections();
 		});
 	}
 
@@ -294,21 +285,18 @@ class DroidtoothPlugin implements DuplexPlugin, EventListener {
 		Map<ContactId, TransportProperties> remote =
 				callback.getRemoteProperties();
 		for (Entry<ContactId, TransportProperties> e : remote.entrySet()) {
-			final ContactId c = e.getKey();
+			ContactId c = e.getKey();
 			if (connected.contains(c)) continue;
-			final String address = e.getValue().get(PROP_ADDRESS);
+			String address = e.getValue().get(PROP_ADDRESS);
 			if (StringUtils.isNullOrEmpty(address)) continue;
-			final String uuid = e.getValue().get(PROP_UUID);
+			String uuid = e.getValue().get(PROP_UUID);
 			if (StringUtils.isNullOrEmpty(uuid)) continue;
-			ioExecutor.execute(new Runnable() {
+			ioExecutor.execute(() -> {
-				@Override
+				if (!running) return;
-				public void run() {
+				BluetoothSocket s = connect(address, uuid);
-					if (!running) return;
+				if (s != null) {
-					BluetoothSocket s = connect(address, uuid);
+					backoff.reset();
-					if (s != null) {
+					callback.outgoingConnectionCreated(c, wrapSocket(s));
-						backoff.reset();
-						callback.outgoingConnectionCreated(c, wrapSocket(s));
-					}
 				}
 			});
 		}
@@ -438,21 +426,11 @@ class DroidtoothPlugin implements DuplexPlugin, EventListener {
 	}
 
 	private void enableAdapterAsync() {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(this::enableAdapter);
-			@Override
-			public void run() {
-				enableAdapter();
-			}
-		});
 	}
 
 	private void disableAdapterAsync() {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(this::disableAdapter);
-			@Override
-			public void run() {
-				disableAdapter();
-			}
-		});
 	}
 
 	private class BluetoothStateReceiver extends BroadcastReceiver {
@@ -490,16 +468,13 @@ class DroidtoothPlugin implements DuplexPlugin, EventListener {
 
 		@Override
 		public Callable<KeyAgreementConnection> listen() {
-			return new Callable<KeyAgreementConnection>() {
+			return () -> {
-				@Override
+				BluetoothSocket s = ss.accept();
-				public KeyAgreementConnection call() throws IOException {
+				if (LOG.isLoggable(INFO))
-					BluetoothSocket s = ss.accept();
+					LOG.info(ID.getString() + ": Incoming connection");
-					if (LOG.isLoggable(INFO))
+				return new KeyAgreementConnection(
-						LOG.info(ID.getString() + ": Incoming connection");
+						new DroidtoothTransportConnection(
-					return new KeyAgreementConnection(
+								DroidtoothPlugin.this, s), ID);
-							new DroidtoothTransportConnection(
-									DroidtoothPlugin.this, s), ID);
-				}
 			};
 		}
 

bramble-android/src/main/java/org/briarproject/bramble/plugin/tor/TorPlugin.java

@@ -149,7 +149,8 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		cookieFile = new File(torDirectory, ".tor/control_auth_cookie");
 		Object o = appContext.getSystemService(POWER_SERVICE);
 		PowerManager pm = (PowerManager) o;
-		wakeLock = pm.newWakeLock(PARTIAL_WAKE_LOCK, "TorPlugin");
+		// This tag will prevent Huawei's powermanager from killing us.
+		wakeLock = pm.newWakeLock(PARTIAL_WAKE_LOCK, "LocationManagerService");
 		wakeLock.setReferenceCounted(false);
 	}
 
@@ -369,57 +370,45 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void sendDevReports() {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(() -> {
-			@Override
+			// TODO: Trigger this with a TransportEnabledEvent
-			public void run() {
+			File reportDir = AndroidUtils.getReportDir(appContext);
-				// TODO: Trigger this with a TransportEnabledEvent
+			reporter.sendReports(reportDir);
-				File reportDir = AndroidUtils.getReportDir(appContext);
-				reporter.sendReports(reportDir);
-			}
 		});
 	}
 
 	private void bind() {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(() -> {
-			@Override
+			// If there's already a port number stored in config, reuse it
-			public void run() {
+			String portString = callback.getSettings().get(PREF_TOR_PORT);
-				// If there's already a port number stored in config, reuse it
+			int port;
-				String portString = callback.getSettings().get(PREF_TOR_PORT);
+			if (StringUtils.isNullOrEmpty(portString)) port = 0;
-				int port;
+			else port = Integer.parseInt(portString);
-				if (StringUtils.isNullOrEmpty(portString)) port = 0;
+			// Bind a server socket to receive connections from Tor
-				else port = Integer.parseInt(portString);
+			ServerSocket ss = null;
-				// Bind a server socket to receive connections from Tor
+			try {
-				ServerSocket ss = null;
+				ss = new ServerSocket();
-				try {
+				ss.bind(new InetSocketAddress("127.0.0.1", port));
-					ss = new ServerSocket();
+			} catch (IOException e) {
-					ss.bind(new InetSocketAddress("127.0.0.1", port));
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-				} catch (IOException e) {
+				tryToClose(ss);
-					if (LOG.isLoggable(WARNING))
+				return;
-						LOG.log(WARNING, e.toString(), e);
-					tryToClose(ss);
-					return;
-				}
-				if (!running) {
-					tryToClose(ss);
-					return;
-				}
-				socket = ss;
-				// Store the port number
-				final String localPort = String.valueOf(ss.getLocalPort());
-				Settings s = new Settings();
-				s.put(PREF_TOR_PORT, localPort);
-				callback.mergeSettings(s);
-				// Create a hidden service if necessary
-				ioExecutor.execute(new Runnable() {
-					@Override
-					public void run() {
-						publishHiddenService(localPort);
-					}
-				});
-				backoff.reset();
-				// Accept incoming hidden service connections from Tor
-				acceptContactConnections(ss);
 			}
+			if (!running) {
+				tryToClose(ss);
+				return;
+			}
+			socket = ss;
+			// Store the port number
+			String localPort = String.valueOf(ss.getLocalPort());
+			Settings s = new Settings();
+			s.put(PREF_TOR_PORT, localPort);
+			callback.mergeSettings(s);
+			// Create a hidden service if necessary
+			ioExecutor.execute(() -> publishHiddenService(localPort));
+			backoff.reset();
+			// Accept incoming hidden service connections from Tor
+			acceptContactConnections(ss);
 		});
 	}
 
@@ -547,17 +536,13 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		}
 	}
 
-	private void connectAndCallBack(final ContactId c,
+	private void connectAndCallBack(ContactId c, TransportProperties p) {
-			final TransportProperties p) {
+		ioExecutor.execute(() -> {
-		ioExecutor.execute(new Runnable() {
+			if (!isRunning()) return;
-			@Override
+			DuplexTransportConnection d = createConnection(p);
-			public void run() {
+			if (d != null) {
-				if (!isRunning()) return;
+				backoff.reset();
-				DuplexTransportConnection d = createConnection(p);
+				callback.outgoingConnectionCreated(c, d);
-				if (d != null) {
-					backoff.reset();
-					callback.outgoingConnectionCreated(c, d);
-				}
 			}
 		});
 	}
@@ -690,48 +675,43 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void updateConnectionStatus() {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(() -> {
-			@Override
+			if (!running) return;
-			public void run() {
-				if (!running) return;
 
-				Object o = appContext.getSystemService(CONNECTIVITY_SERVICE);
+			Object o = appContext.getSystemService(CONNECTIVITY_SERVICE);
-				ConnectivityManager cm = (ConnectivityManager) o;
+			ConnectivityManager cm = (ConnectivityManager) o;
-				NetworkInfo net = cm.getActiveNetworkInfo();
+			NetworkInfo net = cm.getActiveNetworkInfo();
-				boolean online = net != null && net.isConnected();
+			boolean online = net != null && net.isConnected();
-				boolean wifi = online && net.getType() == TYPE_WIFI;
+			boolean wifi = online && net.getType() == TYPE_WIFI;
-				String country = locationUtils.getCurrentCountry();
+			String country = locationUtils.getCurrentCountry();
-				boolean blocked = TorNetworkMetadata.isTorProbablyBlocked(
+			boolean blocked = TorNetworkMetadata.isTorProbablyBlocked(
-						country);
+					country);
-				Settings s = callback.getSettings();
+			Settings s = callback.getSettings();
-				int network = s.getInt(PREF_TOR_NETWORK,
+			int network = s.getInt(PREF_TOR_NETWORK, PREF_TOR_NETWORK_ALWAYS);
-						PREF_TOR_NETWORK_ALWAYS);
 
-				if (LOG.isLoggable(INFO)) {
+			if (LOG.isLoggable(INFO)) {
-					LOG.info("Online: " + online + ", wifi: " + wifi);
+				LOG.info("Online: " + online + ", wifi: " + wifi);
-					if ("".equals(country)) LOG.info("Country code unknown");
+				if ("".equals(country)) LOG.info("Country code unknown");
-					else LOG.info("Country code: " + country);
+				else LOG.info("Country code: " + country);
-				}
+			}
-
+
-				try {
+			try {
-					if (!online) {
+				if (!online) {
-						LOG.info("Disabling network, device is offline");
+					LOG.info("Disabling network, device is offline");
-						enableNetwork(false);
+					enableNetwork(false);
-					} else if (blocked) {
+				} else if (blocked) {
-						LOG.info("Disabling network, country is blocked");
+					LOG.info("Disabling network, country is blocked");
-						enableNetwork(false);
+					enableNetwork(false);
-					} else if (network == PREF_TOR_NETWORK_NEVER
+				} else if (network == PREF_TOR_NETWORK_NEVER
-							|| (network == PREF_TOR_NETWORK_WIFI && !wifi)) {
+						|| (network == PREF_TOR_NETWORK_WIFI && !wifi)) {
-						LOG.info("Disabling network due to data setting");
+					LOG.info("Disabling network due to data setting");
-						enableNetwork(false);
+					enableNetwork(false);
-					} else {
+				} else {
-						LOG.info("Enabling network");
+					LOG.info("Enabling network");
-						enableNetwork(true);
+					enableNetwork(true);
-					}
-				} catch (IOException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
 				}
+			} catch (IOException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			}
 		});
 	}

bramble-android/src/main/java/org/briarproject/bramble/system/AndroidExecutorImpl.java

@@ -27,14 +27,11 @@ class AndroidExecutorImpl implements AndroidExecutor {
 	@Inject
 	AndroidExecutorImpl(Application app) {
 		uiHandler = new Handler(app.getApplicationContext().getMainLooper());
-		loop = new Runnable() {
+		loop = () -> {
-			@Override
+			Looper.prepare();
-			public void run() {
+			backgroundHandler = new Handler();
-				Looper.prepare();
+			startLatch.countDown();
-				backgroundHandler = new Handler();
+			Looper.loop();
-				startLatch.countDown();
-				Looper.loop();
-			}
 		};
 	}
 

bramble-api/build.gradle

@@ -1,30 +1,39 @@
-apply plugin: 'java'
+apply plugin: 'java-library'
-sourceCompatibility = 1.6
+sourceCompatibility = 1.8
-targetCompatibility = 1.6
+targetCompatibility = 1.8
 
 apply plugin: 'witness'
 
 dependencies {
-	compile "com.google.dagger:dagger:2.0.2"
+	implementation "com.google.dagger:dagger:2.0.2"
-	compile 'com.google.dagger:dagger-compiler:2.0.2'
+	implementation 'com.google.code.findbugs:jsr305:3.0.2'
-	compile 'com.google.code.findbugs:jsr305:3.0.2'
 
-	testCompile 'junit:junit:4.12'
+	testImplementation 'junit:junit:4.12'
-	testCompile "org.jmock:jmock:2.8.2"
+	testImplementation "org.jmock:jmock:2.8.2"
-	testCompile "org.jmock:jmock-junit4:2.8.2"
+	testImplementation "org.jmock:jmock-junit4:2.8.2"
-	testCompile "org.jmock:jmock-legacy:2.8.2"
+	testImplementation "org.jmock:jmock-legacy:2.8.2"
-	testCompile "org.hamcrest:hamcrest-library:1.3"
+	testImplementation "org.hamcrest:hamcrest-library:1.3"
-	testCompile "org.hamcrest:hamcrest-core:1.3"
+	testImplementation "org.hamcrest:hamcrest-core:1.3"
 }
 
 dependencyVerification {
 	verify = [
-			'com.google.dagger:dagger:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
+			'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
-			'com.google.dagger:dagger-compiler:b74bc9de063dd4c6400b232231f2ef5056145b8fbecbf5382012007dd1c071b3',
+			'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
-			'com.google.code.findbugs:jsr305:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
+			'com.google.dagger:dagger:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
-			'javax.inject:javax.inject:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
+			'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
-			'com.google.dagger:dagger-producers:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
+			'junit:junit:4.12:junit-4.12.jar:59721f0805e223d84b90677887d9ff567dc534d7c502ca903c0c2b17f05c116a',
-			'com.google.guava:guava:d664fbfc03d2e5ce9cab2a44fb01f1d0bf9dfebeccc1a473b1f9ea31f79f6f99',
+			'org.apache.ant:ant-launcher:1.9.4:ant-launcher-1.9.4.jar:7bccea20b41801ca17bcbc909a78c835d0f443f12d639c77bd6ae3d05861608d',
+			'org.apache.ant:ant:1.9.4:ant-1.9.4.jar:649ae0730251de07b8913f49286d46bba7b92d47c5f332610aa426c4f02161d8',
+			'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
+			'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
+			'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
+			'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',
+			'org.jmock:jmock-legacy:2.8.2:jmock-legacy-2.8.2.jar:f2b985a5c08a9edb7f37612330c058809da3f6a6d63ce792426ebf8ff0d6d31b',
+			'org.jmock:jmock-testjar:2.8.2:jmock-testjar-2.8.2.jar:8900860f72c474e027cf97fe78dcbf154a1aa7fc62b6845c5fb4e4f3c7bc8760',
+			'org.jmock:jmock:2.8.2:jmock-2.8.2.jar:6c73cb4a2e6dbfb61fd99c9a768539c170ab6568e57846bd60dbf19596b65b16',
+			'org.objenesis:objenesis:2.1:objenesis-2.1.jar:c74330cc6b806c804fd37e74487b4fe5d7c2750c5e15fbc6efa13bdee1bdef80',
+			'org.ow2.asm:asm:5.0.4:asm-5.0.4.jar:896618ed8ae62702521a78bc7be42b7c491a08e6920a15f89a3ecdec31e9a220',
 	]
 }
 
@@ -39,3 +48,8 @@ task jarTest(type: Jar, dependsOn: testClasses) {
 artifacts {
 	testOutput jarTest
 }
+
+// If a Java 6 JRE is available, check we're not using any Java 7 or 8 APIs
+tasks.withType(JavaCompile) {
+	useJava6StandardLibrary(it)
+}

bramble-api/src/main/java/org/briarproject/bramble/api/client/BdfMessageContext.java

@@ -23,7 +23,7 @@ public class BdfMessageContext {
 	}
 
 	public BdfMessageContext(BdfDictionary dictionary) {
-		this(dictionary, Collections.<MessageId>emptyList());
+		this(dictionary, Collections.emptyList());
 	}
 
 	public BdfDictionary getDictionary() {

bramble-api/src/main/java/org/briarproject/bramble/api/client/ContactGroupFactory.java

@@ -12,18 +12,19 @@ public interface ContactGroupFactory {
 	/**
 	 * Creates a group that is not shared with any contacts.
 	 */
-	Group createLocalGroup(ClientId clientId);
+	Group createLocalGroup(ClientId clientId, int clientVersion);
 
 	/**
 	 * Creates a group for the given client to share with the given contact.
 	 */
-	Group createContactGroup(ClientId clientId, Contact contact);
+	Group createContactGroup(ClientId clientId, int clientVersion,
+			Contact contact);
 
 	/**
 	 * Creates a group for the given client to share between the given authors
 	 * identified by their AuthorIds.
 	 */
-	Group createContactGroup(ClientId clientId, AuthorId authorId1,
+	Group createContactGroup(ClientId clientId, int clientVersion,
-			AuthorId authorId2);
+			AuthorId authorId1, AuthorId authorId2);
 
 }

bramble-api/src/main/java/org/briarproject/bramble/api/contact/ContactExchangeTask.java

@@ -12,6 +12,32 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 @NotNullByDefault
 public interface ContactExchangeTask {
 
+	/**
+	 * The current version of the contact exchange protocol
+	 */
+	int PROTOCOL_VERSION = 0;
+
+	/**
+	 * Label for deriving Alice's header key from the master secret.
+	 */
+	String ALICE_KEY_LABEL =
+			"org.briarproject.bramble.contact/ALICE_HEADER_KEY";
+
+	/**
+	 * Label for deriving Bob's header key from the master secret.
+	 */
+	String BOB_KEY_LABEL = "org.briarproject.bramble.contact/BOB_HEADER_KEY";
+
+	/**
+	 * Label for deriving Alice's key binding nonce from the master secret.
+	 */
+	String ALICE_NONCE_LABEL = "org.briarproject.bramble.contact/ALICE_NONCE";
+
+	/**
+	 * Label for deriving Bob's key binding nonce from the master secret.
+	 */
+	String BOB_NONCE_LABEL = "org.briarproject.bramble.contact/BOB_NONCE";
+
 	/**
 	 * Exchanges contact information with a remote peer.
 	 */

bramble-api/src/main/java/org/briarproject/bramble/api/crypto/CryptoComponent.java

@@ -1,8 +1,5 @@
 package org.briarproject.bramble.api.crypto;
 
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.transport.TransportKeys;
-
 import java.security.GeneralSecurityException;
 import java.security.SecureRandom;
 
@@ -20,156 +17,98 @@ public interface CryptoComponent {
 
 	KeyParser getSignatureKeyParser();
 
+	KeyPair generateEdKeyPair();
+
+	KeyParser getEdKeyParser();
+
 	KeyParser getMessageKeyParser();
 
 	/**
-	 * Derives a stream header key from the given master secret.
+	 * Derives another secret key from the given secret key.
-	 * @param alice whether the key is for use by Alice or Bob.
-	 */
-	SecretKey deriveHeaderKey(SecretKey master, boolean alice);
-
-	/**
-	 * Derives a message authentication code key from the given master secret.
-	 * @param alice whether the key is for use by Alice or Bob.
-	 */
-	SecretKey deriveMacKey(SecretKey master, boolean alice);
-
-	/**
-	 * Derives a nonce from the given master secret for one of the parties to
-	 * sign.
-	 * @param alice whether the nonce is for use by Alice or Bob.
-	 */
-	byte[] deriveSignatureNonce(SecretKey master, boolean alice);
-
-	/**
-	 * Derives a commitment to the provided public key.
-	 * <p/>
-	 * Part of BQP.
 	 *
-	 * @param publicKey the public key
+	 * @param label a namespaced label indicating the purpose of the derived
-	 * @return the commitment to the provided public key.
+	 * key, to prevent it from being repurposed or colliding with a key derived
+	 * for another purpose
 	 */
-	byte[] deriveKeyCommitment(byte[] publicKey);
+	SecretKey deriveKey(String label, SecretKey k, byte[]... inputs);
 
 	/**
 	 * Derives a common shared secret from two public keys and one of the
 	 * corresponding private keys.
-	 * <p/>
-	 * Part of BQP.
 	 *
-	 * @param theirPublicKey the ephemeral public key of the remote party
+	 * @param label a namespaced label indicating the purpose of this shared
-	 * @param ourKeyPair our ephemeral keypair
+	 * secret, to prevent it from being repurposed or colliding with a shared
-	 * @param alice true if ourKeyPair belongs to Alice
+	 * secret derived for another purpose
+	 * @param theirPublicKey the public key of the remote party
+	 * @param ourKeyPair the key pair of the local party
 	 * @return the shared secret
-	 * @throws GeneralSecurityException
 	 */
-	SecretKey deriveSharedSecret(byte[] theirPublicKey, KeyPair ourKeyPair,
+	SecretKey deriveSharedSecret(String label, PublicKey theirPublicKey,
-			boolean alice) throws GeneralSecurityException;
+			KeyPair ourKeyPair, byte[]... inputs)
+			throws GeneralSecurityException;
 
 	/**
-	 * Derives the content of a confirmation record.
+	 * Signs the given byte[] with the given ECDSA private key.
-	 * <p/>
-	 * Part of BQP.
 	 *
-	 * @param sharedSecret the common shared secret
+	 * @param label a namespaced label indicating the purpose of this
-	 * @param theirPayload the commit payload from the remote party
+	 * signature, to prevent it from being repurposed or colliding with a
-	 * @param ourPayload the commit payload we sent
+	 * signature created for another purpose
-	 * @param theirPublicKey the ephemeral public key of the remote party
-	 * @param ourKeyPair our ephemeral keypair
-	 * @param alice true if ourKeyPair belongs to Alice
-	 * @param aliceRecord true if the confirmation record is for use by Alice
-	 * @return the confirmation record
-	 */
-	byte[] deriveConfirmationRecord(SecretKey sharedSecret,
-			byte[] theirPayload, byte[] ourPayload,
-			byte[] theirPublicKey, KeyPair ourKeyPair,
-			boolean alice, boolean aliceRecord);
-
-	/**
-	 * Derives a master secret from the given shared secret.
-	 * <p/>
-	 * Part of BQP.
-	 *
-	 * @param sharedSecret the common shared secret
-	 * @return the master secret
-	 */
-	SecretKey deriveMasterSecret(SecretKey sharedSecret);
-
-	/**
-	 * Derives a master secret from two public keys and one of the corresponding
-	 * private keys.
-	 * <p/>
-	 * This is a helper method that calls
-	 * deriveMasterSecret(deriveSharedSecret(theirPublicKey, ourKeyPair, alice))
-	 *
-	 * @param theirPublicKey the ephemeral public key of the remote party
-	 * @param ourKeyPair our ephemeral keypair
-	 * @param alice true if ourKeyPair belongs to Alice
-	 * @return the shared secret
-	 * @throws GeneralSecurityException
-	 */
-	SecretKey deriveMasterSecret(byte[] theirPublicKey, KeyPair ourKeyPair,
-			boolean alice) throws GeneralSecurityException;
-
-	/**
-	 * Derives initial transport keys for the given transport in the given
-	 * rotation period from the given master secret.
-	 * @param alice whether the keys are for use by Alice or Bob.
-	 */
-	TransportKeys deriveTransportKeys(TransportId t, SecretKey master,
-			long rotationPeriod, boolean alice);
-
-	/**
-	 * Rotates the given transport keys to the given rotation period. If the
-	 * keys are for a future rotation period they are not rotated.
-	 */
-	TransportKeys rotateTransportKeys(TransportKeys k, long rotationPeriod);
-
-	/** Encodes the pseudo-random tag that is used to recognise a stream. */
-	void encodeTag(byte[] tag, SecretKey tagKey, int protocolVersion,
-			long streamNumber);
-
-	/**
-	 * Signs the given byte[] with the given PrivateKey.
-	 *
-	 * @param label A label specific to this signature
-	 *              to ensure that the signature cannot be repurposed
 	 */
 	byte[] sign(String label, byte[] toSign, byte[] privateKey)
 			throws GeneralSecurityException;
 
 	/**
-	 * Verifies that the given signature is valid for the signedData
+	 * Signs the given byte[] with the given Ed25519 private key.
-	 * and the given publicKey.
 	 *
-	 * @param label A label that was specific to this signature
+	 * @param label A label specific to this signature
 	 *              to ensure that the signature cannot be repurposed
+	 */
+	byte[] signEd(String label, byte[] toSign, byte[] privateKey)
+			throws GeneralSecurityException;
+
+	/**
+	 * Verifies that the given signature is valid for the signed data
+	 * and the given ECDSA public key.
+	 *
+	 * @param label a namespaced label indicating the purpose of this
+	 * signature, to prevent it from being repurposed or colliding with a
+	 * signature created for another purpose
 	 * @return true if the signature was valid, false otherwise.
 	 */
 	boolean verify(String label, byte[] signedData, byte[] publicKey,
 			byte[] signature) throws GeneralSecurityException;
 
+	/**
+	 * Verifies that the given signature is valid for the signed data
+	 * and the given Ed25519 public key.
+	 *
+	 * @param label A label that was specific to this signature
+	 *              to ensure that the signature cannot be repurposed
+	 * @return true if the signature was valid, false otherwise.
+	 */
+	boolean verifyEd(String label, byte[] signedData, byte[] publicKey,
+			byte[] signature) throws GeneralSecurityException;
+
 	/**
 	 * Returns the hash of the given inputs. The inputs are unambiguously
 	 * combined by prefixing each input with its length.
 	 *
-	 * @param label A label specific to this hash to ensure that hashes
+	 * @param label a namespaced label indicating the purpose of this hash, to
-	 *              calculated for distinct purposes don't collide.
+	 * prevent it from being repurposed or colliding with a hash created for
+	 * another purpose
 	 */
 	byte[] hash(String label, byte[]... inputs);
 
-	/**
-	 * Returns the length of hashes produced by
-	 * the {@link CryptoComponent#hash(String, byte[]...)} method.
-	 */
-	int getHashLength();
-
 	/**
 	 * Returns a message authentication code with the given key over the
 	 * given inputs. The inputs are unambiguously combined by prefixing each
 	 * input with its length.
+	 *
+	 * @param label a namespaced label indicating the purpose of this MAC, to
+	 * prevent it from being repurposed or colliding with a MAC created for
+	 * another purpose
 	 */
-	byte[] mac(SecretKey macKey, byte[]... inputs);
+	byte[] mac(String label, SecretKey macKey, byte[]... inputs);
 
 	/**
 	 * Encrypts and authenticates the given plaintext so it can be written to

bramble-api/src/main/java/org/briarproject/bramble/api/crypto/KeyAgreementCrypto.java

@@ -0,0 +1,50 @@
+package org.briarproject.bramble.api.crypto;
+
+/**
+ * Crypto operations for the key agreement protocol - see
+ * https://code.briarproject.org/akwizgran/briar-spec/blob/master/protocols/BQP.md
+ */
+public interface KeyAgreementCrypto {
+
+	/**
+	 * Hash label for public key commitment.
+	 */
+	String COMMIT_LABEL = "org.briarproject.bramble.keyagreement/COMMIT";
+
+	/**
+	 * Key derivation label for confirmation record.
+	 */
+	String CONFIRMATION_KEY_LABEL =
+			"org.briarproject.bramble.keyagreement/CONFIRMATION_KEY";
+
+	/**
+	 * MAC label for confirmation record.
+	 */
+	String CONFIRMATION_MAC_LABEL =
+			"org.briarproject.bramble.keyagreement/CONFIRMATION_MAC";
+
+	/**
+	 * Derives a commitment to the provided public key.
+	 *
+	 * @param publicKey the public key
+	 * @return the commitment to the provided public key.
+	 */
+	byte[] deriveKeyCommitment(PublicKey publicKey);
+
+	/**
+	 * Derives the content of a confirmation record.
+	 *
+	 * @param sharedSecret the common shared secret
+	 * @param theirPayload the key exchange payload of the remote party
+	 * @param ourPayload the key exchange payload of the local party
+	 * @param theirPublicKey the ephemeral public key of the remote party
+	 * @param ourKeyPair our ephemeral key pair of the local party
+	 * @param alice true if the local party is Alice
+	 * @param aliceRecord true if the confirmation record is for use by Alice
+	 * @return the confirmation record
+	 */
+	byte[] deriveConfirmationRecord(SecretKey sharedSecret,
+			byte[] theirPayload, byte[] ourPayload,
+			PublicKey theirPublicKey, KeyPair ourKeyPair,
+			boolean alice, boolean aliceRecord);
+}

bramble-api/src/main/java/org/briarproject/bramble/api/crypto/TransportCrypto.java

@@ -0,0 +1,32 @@
+package org.briarproject.bramble.api.crypto;
+
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.transport.TransportKeys;
+
+/**
+ * Crypto operations for the transport security protocol - see
+ * https://code.briarproject.org/akwizgran/briar-spec/blob/master/protocols/BTP.md
+ */
+public interface TransportCrypto {
+
+	/**
+	 * Derives initial transport keys for the given transport in the given
+	 * rotation period from the given master secret.
+	 *
+	 * @param alice whether the keys are for use by Alice or Bob.
+	 */
+	TransportKeys deriveTransportKeys(TransportId t, SecretKey master,
+			long rotationPeriod, boolean alice);
+
+	/**
+	 * Rotates the given transport keys to the given rotation period. If the
+	 * keys are for the given period or any later period they are not rotated.
+	 */
+	TransportKeys rotateTransportKeys(TransportKeys k, long rotationPeriod);
+
+	/**
+	 * Encodes the pseudo-random tag that is used to recognise a stream.
+	 */
+	void encodeTag(byte[] tag, SecretKey tagKey, int protocolVersion,
+			long streamNumber);
+}

bramble-api/src/main/java/org/briarproject/bramble/api/data/BdfDictionary.java

@@ -4,11 +4,14 @@ import org.briarproject.bramble.api.Bytes;
 import org.briarproject.bramble.api.FormatException;
 
 import java.util.Map;
-import java.util.concurrent.ConcurrentSkipListMap;
+import java.util.Map.Entry;
+import java.util.TreeMap;
 
 import javax.annotation.Nullable;
+import javax.annotation.concurrent.NotThreadSafe;
 
-public class BdfDictionary extends ConcurrentSkipListMap<String, Object> {
+@NotThreadSafe
+public class BdfDictionary extends TreeMap<String, Object> {
 
 	public static final Object NULL_VALUE = new Object();
 

bramble-api/src/main/java/org/briarproject/bramble/api/data/BdfList.java

@@ -3,15 +3,17 @@ package org.briarproject.bramble.api.data;
 import org.briarproject.bramble.api.Bytes;
 import org.briarproject.bramble.api.FormatException;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
-import java.util.Vector;
 
 import javax.annotation.Nullable;
+import javax.annotation.concurrent.NotThreadSafe;
 
 import static org.briarproject.bramble.api.data.BdfDictionary.NULL_VALUE;
 
-public class BdfList extends Vector<Object> {
+@NotThreadSafe
+public class BdfList extends ArrayList<Object> {
 
 	/**
 	 * Factory method for constructing lists inline.

bramble-api/src/main/java/org/briarproject/bramble/api/db/DatabaseComponent.java

@@ -122,8 +122,9 @@ public interface DatabaseComponent {
 			throws DbException;
 
 	/**
-	 * Deletes the message with the given ID. The message ID and any other
+	 * Deletes the message with the given ID. Unlike
-	 * associated data are not deleted.
+	 * {@link #removeMessage(Transaction, MessageId)}, the message ID and any
+	 * other associated data are not deleted.
 	 */
 	void deleteMessage(Transaction txn, MessageId m) throws DbException;
 
@@ -452,6 +453,11 @@ public interface DatabaseComponent {
 	 */
 	void removeLocalAuthor(Transaction txn, AuthorId a) throws DbException;
 
+	/**
+	 * Removes a message (and all associated state) from the database.
+	 */
+	void removeMessage(Transaction txn, MessageId m) throws DbException;
+
 	/**
 	 * Removes a transport (and all associated state) from the database.
 	 */

bramble-api/src/main/java/org/briarproject/bramble/api/db/Metadata.java

@@ -1,11 +1,11 @@
 package org.briarproject.bramble.api.db;
 
-import java.util.Hashtable;
+import java.util.TreeMap;
 
-import javax.annotation.concurrent.ThreadSafe;
+import javax.annotation.concurrent.NotThreadSafe;
 
-@ThreadSafe
+@NotThreadSafe
-public class Metadata extends Hashtable<String, byte[]> {
+public class Metadata extends TreeMap<String, byte[]> {
 
 	/**
 	 * Special value to indicate that a key is being removed.

bramble-api/src/main/java/org/briarproject/bramble/api/db/Transaction.java

@@ -45,7 +45,7 @@ public class Transaction {
 	 * committed.
 	 */
 	public void attach(Event e) {
-		if (events == null) events = new ArrayList<Event>();
+		if (events == null) events = new ArrayList<>();
 		events.add(e);
 	}
 

bramble-api/src/main/java/org/briarproject/bramble/api/identity/AuthorId.java

@@ -16,7 +16,7 @@ public class AuthorId extends UniqueId {
 	/**
 	 * Label for hashing authors to calculate their identities.
 	 */
-	public static final String LABEL = "org.briarproject.bramble.AUTHOR_ID";
+	public static final String LABEL = "org.briarproject.bramble/AUTHOR_ID";
 
 	public AuthorId(byte[] id) {
 		super(id);

bramble-api/src/main/java/org/briarproject/bramble/api/keyagreement/KeyAgreementConstants.java

@@ -5,7 +5,7 @@ public interface KeyAgreementConstants {
 	/**
 	 * The current version of the BQP protocol.
 	 */
-	byte PROTOCOL_VERSION = 2;
+	byte PROTOCOL_VERSION = 3;
 
 	/**
 	 * The length of the record header in bytes.
@@ -22,7 +22,10 @@ public interface KeyAgreementConstants {
 	 */
 	int COMMIT_LENGTH = 16;
 
-	long CONNECTION_TIMEOUT = 20 * 1000; // Milliseconds
+	/**
+	 * The connection timeout in milliseconds.
+	 */
+	long CONNECTION_TIMEOUT = 20 * 1000;
 
 	/**
 	 * The transport identifier for Bluetooth.
@@ -33,4 +36,16 @@ public interface KeyAgreementConstants {
 	 * The transport identifier for LAN.
 	 */
 	int TRANSPORT_ID_LAN = 1;
+
+	/**
+	 * Label for deriving the shared secret.
+	 */
+	String SHARED_SECRET_LABEL =
+			"org.briarproject.bramble.keyagreement/SHARED_SECRET";
+
+	/**
+	 * Label for deriving the master secret.
+	 */
+	String MASTER_SECRET_LABEL =
+			"org.briarproject.bramble.keyagreement/MASTER_SECRET";
 }

bramble-api/src/main/java/org/briarproject/bramble/api/keyagreement/KeyAgreementTaskFactory.java

@@ -1,15 +0,0 @@
-package org.briarproject.bramble.api.keyagreement;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-/**
- * Manages tasks for conducting key agreements with remote peers.
- */
-@NotNullByDefault
-public interface KeyAgreementTaskFactory {
-
-	/**
-	 * Gets the current key agreement task.
-	 */
-	KeyAgreementTask createTask();
-}

bramble-api/src/main/java/org/briarproject/bramble/api/properties/TransportPropertyManager.java

@@ -17,6 +17,11 @@ public interface TransportPropertyManager {
 	 */
 	ClientId CLIENT_ID = new ClientId("org.briarproject.briar.properties");
 
+	/**
+	 * The current version of the transport property client.
+	 */
+	int CLIENT_VERSION = 0;
+
 	/**
 	 * Stores the given properties received while adding a contact - they will
 	 * be superseded by any properties synced from the contact.
@@ -33,7 +38,7 @@ public interface TransportPropertyManager {
 	/**
 	 * Returns the local transport properties for all transports.
 	 * <br/>
-	 * Read-Only
+	 * TODO: Transaction can be read-only when code is simplified
 	 */
 	Map<TransportId, TransportProperties> getLocalProperties(Transaction txn)
 			throws DbException;

bramble-api/src/main/java/org/briarproject/bramble/api/sync/ClientId.java

@@ -36,4 +36,8 @@ public class ClientId implements Comparable<ClientId> {
 		return id.hashCode();
 	}
 
+	@Override
+	public String toString() {
+		return id;
+	}
 }

bramble-api/src/main/java/org/briarproject/bramble/api/sync/GroupFactory.java

@@ -6,7 +6,7 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 public interface GroupFactory {
 
 	/**
-	 * Creates a group with the given client ID and descriptor.
+	 * Creates a group with the given client ID, client version and descriptor.
 	 */
-	Group createGroup(ClientId c, byte[] descriptor);
+	Group createGroup(ClientId c, int clientVersion, byte[] descriptor);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/sync/GroupId.java

@@ -15,7 +15,7 @@ public class GroupId extends UniqueId {
 	/**
 	 * Label for hashing groups to calculate their identifiers.
 	 */
-	public static final String LABEL = "org.briarproject.bramble.GROUP_ID";
+	public static final String LABEL = "org.briarproject.bramble/GROUP_ID";
 
 	public GroupId(byte[] id) {
 		super(id);

bramble-api/src/main/java/org/briarproject/bramble/api/sync/MessageContext.java

@@ -22,7 +22,7 @@ public class MessageContext {
 	}
 
 	public MessageContext(Metadata metadata) {
-		this(metadata, Collections.<MessageId>emptyList());
+		this(metadata, Collections.emptyList());
 	}
 
 	public Metadata getMetadata() {

bramble-api/src/main/java/org/briarproject/bramble/api/sync/MessageId.java

@@ -16,7 +16,7 @@ public class MessageId extends UniqueId {
 	/**
 	 * Label for hashing messages to calculate their identifiers.
 	 */
-	public static final String LABEL = "org.briarproject.bramble.MESSAGE_ID";
+	public static final String LABEL = "org.briarproject.bramble/MESSAGE_ID";
 
 	public MessageId(byte[] id) {
 		super(id);

bramble-api/src/main/java/org/briarproject/bramble/api/transport/TransportConstants.java

@@ -7,7 +7,7 @@ public interface TransportConstants {
 	/**
 	 * The current version of the transport protocol.
 	 */
-	int PROTOCOL_VERSION = 3;
+	int PROTOCOL_VERSION = 4;
 
 	/**
 	 * The length of the pseudo-random tag in bytes.
@@ -80,4 +80,32 @@ public interface TransportConstants {
 	 * The size of the reordering window.
 	 */
 	int REORDERING_WINDOW_SIZE = 32;
+
+	/**
+	 * Label for deriving Alice's initial tag key from the master secret.
+	 */
+	String ALICE_TAG_LABEL = "org.briarproject.bramble.transport/ALICE_TAG_KEY";
+
+	/**
+	 * Label for deriving Bob's initial tag key from the master secret.
+	 */
+	String BOB_TAG_LABEL = "org.briarproject.bramble.transport/BOB_TAG_KEY";
+
+	/**
+	 * Label for deriving Alice's initial header key from the master secret.
+	 */
+	String ALICE_HEADER_LABEL =
+			"org.briarproject.bramble.transport/ALICE_HEADER_KEY";
+
+	/**
+	 * Label for deriving Bob's initial header key from the master secret.
+	 */
+	String BOB_HEADER_LABEL =
+			"org.briarproject.bramble.transport/BOB_HEADER_KEY";
+
+	/**
+	 * Label for deriving the next period's key in key rotation.
+	 */
+	String ROTATE_LABEL = "org.briarproject.bramble.transport/ROTATE";
+
 }

bramble-api/src/test/java/org/briarproject/bramble/test/BrambleMockTestCase.java

@@ -3,8 +3,7 @@ package org.briarproject.bramble.test;
 import org.jmock.Mockery;
 import org.junit.After;
 
-public abstract class BrambleMockTestCase extends
+public abstract class BrambleMockTestCase extends BrambleTestCase {
-		BrambleTestCase {
 
 	protected final Mockery context = new Mockery();
 

bramble-api/src/test/java/org/briarproject/bramble/test/BrambleTestCase.java

@@ -8,12 +8,9 @@ public abstract class BrambleTestCase {
 
 	public BrambleTestCase() {
 		// Ensure exceptions thrown on worker threads cause tests to fail
-		UncaughtExceptionHandler fail = new UncaughtExceptionHandler() {
+		UncaughtExceptionHandler fail = (thread, throwable) -> {
-			@Override
+			throwable.printStackTrace();
-			public void uncaughtException(Thread thread, Throwable throwable) {
+			fail();
-				throwable.printStackTrace();
-				fail();
-			}
 		};
 		Thread.setDefaultUncaughtExceptionHandler(fail);
 	}

bramble-core/build.gradle

@@ -1,28 +1,60 @@
-plugins {
+apply plugin: 'java-library'
-	id 'java'
+sourceCompatibility = 1.8
-	id 'net.ltgt.apt' version '0.9'
+targetCompatibility = 1.8
-	id 'idea'
-}
-
-sourceCompatibility = 1.6
-targetCompatibility = 1.6
 
+apply plugin: 'net.ltgt.apt'
+apply plugin: 'idea'
 apply plugin: 'witness'
 
 dependencies {
-	compile project(':bramble-api')
+	implementation project(path: ':bramble-api', configuration: 'default')
-	compile 'com.madgag.spongycastle:core:1.58.0.0'
+	implementation 'com.madgag.spongycastle:core:1.58.0.0'
-	compile 'com.h2database:h2:1.4.192' // This is the last version that supports Java 1.6
+	implementation 'com.h2database:h2:1.4.192' // The last version that supports Java 1.6
-	compile 'org.bitlet:weupnp:0.1.4'
+	implementation 'org.bitlet:weupnp:0.1.4'
+	implementation 'net.i2p.crypto:eddsa:0.2.0'
 
-	testCompile project(path: ':bramble-api', configuration: 'testOutput')
+	apt 'com.google.dagger:dagger-compiler:2.0.2'
+
+	testImplementation project(path: ':bramble-api', configuration: 'testOutput')
+	testImplementation 'org.hsqldb:hsqldb:2.3.5' // The last version that supports Java 1.6
+	testImplementation 'junit:junit:4.12'
+	testImplementation "org.jmock:jmock:2.8.2"
+	testImplementation "org.jmock:jmock-junit4:2.8.2"
+	testImplementation "org.jmock:jmock-legacy:2.8.2"
+	testImplementation "org.hamcrest:hamcrest-library:1.3"
+	testImplementation "org.hamcrest:hamcrest-core:1.3"
+	testImplementation "org.whispersystems:curve25519-java:0.4.1"
+
+	testApt 'com.google.dagger:dagger-compiler:2.0.2'
 }
 
 dependencyVerification {
 	verify = [
-			'com.madgag.spongycastle:core:199617dd5698c5a9312b898c0a4cec7ce9dd8649d07f65d91629f58229d72728',
+			'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
-			'com.h2database:h2:225b22e9857235c46c93861410b60b8c81c10dc8985f4faf188985ba5445126c',
+			'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
-			'org.bitlet:weupnp:88df7e6504929d00bdb832863761385c68ab92af945b04f0770b126270a444fb',
+			'com.google.dagger:dagger-compiler:2.0.2:dagger-compiler-2.0.2.jar:b74bc9de063dd4c6400b232231f2ef5056145b8fbecbf5382012007dd1c071b3',
+			'com.google.dagger:dagger-producers:2.0-beta:dagger-producers-2.0-beta.jar:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
+			'com.google.dagger:dagger:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
+			'com.google.guava:guava:18.0:guava-18.0.jar:d664fbfc03d2e5ce9cab2a44fb01f1d0bf9dfebeccc1a473b1f9ea31f79f6f99',
+			'com.h2database:h2:1.4.192:h2-1.4.192.jar:225b22e9857235c46c93861410b60b8c81c10dc8985f4faf188985ba5445126c',
+			'com.madgag.spongycastle:core:1.58.0.0:core-1.58.0.0.jar:199617dd5698c5a9312b898c0a4cec7ce9dd8649d07f65d91629f58229d72728',
+			'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
+			'junit:junit:4.12:junit-4.12.jar:59721f0805e223d84b90677887d9ff567dc534d7c502ca903c0c2b17f05c116a',
+			'net.i2p.crypto:eddsa:0.2.0:eddsa-0.2.0.jar:a7cb1b85c16e2f0730b9204106929a1d9aaae1df728adc7041a8b8b605692140',
+			'org.apache.ant:ant-launcher:1.9.4:ant-launcher-1.9.4.jar:7bccea20b41801ca17bcbc909a78c835d0f443f12d639c77bd6ae3d05861608d',
+			'org.apache.ant:ant:1.9.4:ant-1.9.4.jar:649ae0730251de07b8913f49286d46bba7b92d47c5f332610aa426c4f02161d8',
+			'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
+			'org.bitlet:weupnp:0.1.4:weupnp-0.1.4.jar:88df7e6504929d00bdb832863761385c68ab92af945b04f0770b126270a444fb',
+			'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
+			'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
+			'org.hsqldb:hsqldb:2.3.5:hsqldb-2.3.5.jar:6676a6977ac98997a80f827ddbd3fe8ca1e0853dad1492512135fd1a222ccfad',
+			'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',
+			'org.jmock:jmock-legacy:2.8.2:jmock-legacy-2.8.2.jar:f2b985a5c08a9edb7f37612330c058809da3f6a6d63ce792426ebf8ff0d6d31b',
+			'org.jmock:jmock-testjar:2.8.2:jmock-testjar-2.8.2.jar:8900860f72c474e027cf97fe78dcbf154a1aa7fc62b6845c5fb4e4f3c7bc8760',
+			'org.jmock:jmock:2.8.2:jmock-2.8.2.jar:6c73cb4a2e6dbfb61fd99c9a768539c170ab6568e57846bd60dbf19596b65b16',
+			'org.objenesis:objenesis:2.1:objenesis-2.1.jar:c74330cc6b806c804fd37e74487b4fe5d7c2750c5e15fbc6efa13bdee1bdef80',
+			'org.ow2.asm:asm:5.0.4:asm-5.0.4.jar:896618ed8ae62702521a78bc7be42b7c491a08e6920a15f89a3ecdec31e9a220',
+			'org.whispersystems:curve25519-java:0.4.1:curve25519-java-0.4.1.jar:7dd659d8822c06c3aea1a47f18fac9e5761e29cab8100030b877db445005f03e',
 	]
 }
 
@@ -37,3 +69,8 @@ task jarTest(type: Jar, dependsOn: testClasses) {
 artifacts {
 	testOutput jarTest
 }
+
+// If a Java 6 JRE is available, check we're not using any Java 7 or 8 APIs
+tasks.withType(JavaCompile) {
+	useJava6StandardLibrary(it)
+}

bramble-core/src/main/java/org/briarproject/bramble/PoliteExecutor.java

@@ -24,7 +24,7 @@ public class PoliteExecutor implements Executor {
 
 	private final Object lock = new Object();
 	@GuardedBy("lock")
-	private final Queue<Runnable> queue = new LinkedList<Runnable>();
+	private final Queue<Runnable> queue = new LinkedList<>();
 	private final Executor delegate;
 	private final int maxConcurrentTasks;
 	private final Logger log;
@@ -48,20 +48,17 @@ public class PoliteExecutor implements Executor {
 	}
 
 	@Override
-	public void execute(final Runnable r) {
+	public void execute(Runnable r) {
-		final long submitted = System.currentTimeMillis();
+		long submitted = System.currentTimeMillis();
-		Runnable wrapped = new Runnable() {
+		Runnable wrapped = () -> {
-			@Override
+			if (log.isLoggable(LOG_LEVEL)) {
-			public void run() {
+				long queued = System.currentTimeMillis() - submitted;
-				if (log.isLoggable(LOG_LEVEL)) {
+				log.log(LOG_LEVEL, "Queue time " + queued + " ms");
-					long queued = System.currentTimeMillis() - submitted;
+			}
-					log.log(LOG_LEVEL, "Queue time " + queued + " ms");
+			try {
-				}
+				r.run();
-				try {
+			} finally {
-					r.run();
+				scheduleNext();
-				} finally {
-					scheduleNext();
-				}
 			}
 		};
 		synchronized (lock) {

bramble-core/src/main/java/org/briarproject/bramble/TimeLoggingExecutor.java

@@ -28,19 +28,16 @@ public class TimeLoggingExecutor extends ThreadPoolExecutor {
 	}
 
 	@Override
-	public void execute(final Runnable r) {
+	public void execute(Runnable r) {
 		if (log.isLoggable(LOG_LEVEL)) {
-			final long submitted = System.currentTimeMillis();
+			long submitted = System.currentTimeMillis();
-			super.execute(new Runnable() {
+			super.execute(() -> {
-				@Override
+				long started = System.currentTimeMillis();
-				public void run() {
+				long queued = started - submitted;
-					long started = System.currentTimeMillis();
+				log.log(LOG_LEVEL, "Queue time " + queued + " ms");
-					long queued = started - submitted;
+				r.run();
-					log.log(LOG_LEVEL, "Queue time " + queued + " ms");
+				long executing = System.currentTimeMillis() - started;
-					r.run();
+				log.log(LOG_LEVEL, "Execution time " + executing + " ms");
-					long executing = System.currentTimeMillis() - started;
-					log.log(LOG_LEVEL, "Execution time " + executing + " ms");
-				}
 			});
 		} else {
 			super.execute(r);

bramble-core/src/main/java/org/briarproject/bramble/client/ClientHelperImpl.java

@@ -201,8 +201,7 @@ class ClientHelperImpl implements ClientHelper {
 	public Map<MessageId, BdfDictionary> getMessageMetadataAsDictionary(
 			Transaction txn, GroupId g) throws DbException, FormatException {
 		Map<MessageId, Metadata> raw = db.getMessageMetadata(txn, g);
-		Map<MessageId, BdfDictionary> parsed =
+		Map<MessageId, BdfDictionary> parsed = new HashMap<>(raw.size());
-				new HashMap<MessageId, BdfDictionary>(raw.size());
 		for (Entry<MessageId, Metadata> e : raw.entrySet())
 			parsed.put(e.getKey(), metadataParser.parse(e.getValue()));
 		return parsed;
@@ -229,8 +228,7 @@ class ClientHelperImpl implements ClientHelper {
 			FormatException {
 		Metadata metadata = metadataEncoder.encode(query);
 		Map<MessageId, Metadata> raw = db.getMessageMetadata(txn, g, metadata);
-		Map<MessageId, BdfDictionary> parsed =
+		Map<MessageId, BdfDictionary> parsed = new HashMap<>(raw.size());
-				new HashMap<MessageId, BdfDictionary>(raw.size());
 		for (Entry<MessageId, Metadata> e : raw.entrySet())
 			parsed.put(e.getKey(), metadataParser.parse(e.getValue()));
 		return parsed;

bramble-core/src/main/java/org/briarproject/bramble/client/ContactGroupFactoryImpl.java

@@ -32,23 +32,25 @@ class ContactGroupFactoryImpl implements ContactGroupFactory {
 	}
 
 	@Override
-	public Group createLocalGroup(ClientId clientId) {
+	public Group createLocalGroup(ClientId clientId, int clientVersion) {
-		return groupFactory.createGroup(clientId, LOCAL_GROUP_DESCRIPTOR);
+		return groupFactory.createGroup(clientId, clientVersion,
+				LOCAL_GROUP_DESCRIPTOR);
 	}
 
 	@Override
-	public Group createContactGroup(ClientId clientId, Contact contact) {
+	public Group createContactGroup(ClientId clientId, int clientVersion,
+			Contact contact) {
 		AuthorId local = contact.getLocalAuthorId();
 		AuthorId remote = contact.getAuthor().getId();
 		byte[] descriptor = createGroupDescriptor(local, remote);
-		return groupFactory.createGroup(clientId, descriptor);
+		return groupFactory.createGroup(clientId, clientVersion, descriptor);
 	}
 
 	@Override
-	public Group createContactGroup(ClientId clientId, AuthorId authorId1,
+	public Group createContactGroup(ClientId clientId, int clientVersion,
-			AuthorId authorId2) {
+			AuthorId authorId1, AuthorId authorId2) {
 		byte[] descriptor = createGroupDescriptor(authorId1, authorId2);
-		return groupFactory.createGroup(clientId, descriptor);
+		return groupFactory.createGroup(clientId, clientVersion, descriptor);
 	}
 
 	private byte[] createGroupDescriptor(AuthorId local, AuthorId remote) {

bramble-core/src/main/java/org/briarproject/bramble/contact/ContactExchangeTaskImpl.java

@@ -141,8 +141,10 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		}
 
 		// Derive the header keys for the transport streams
-		SecretKey aliceHeaderKey = crypto.deriveHeaderKey(masterSecret, true);
+		SecretKey aliceHeaderKey = crypto.deriveKey(ALICE_KEY_LABEL,
-		SecretKey bobHeaderKey = crypto.deriveHeaderKey(masterSecret, false);
+				masterSecret, new byte[] {PROTOCOL_VERSION});
+		SecretKey bobHeaderKey = crypto.deriveKey(BOB_KEY_LABEL, masterSecret,
+				new byte[] {PROTOCOL_VERSION});
 
 		// Create the readers
 		InputStream streamReader =
@@ -156,8 +158,10 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		BdfWriter w = bdfWriterFactory.createWriter(streamWriter);
 
 		// Derive the nonces to be signed
-		byte[] aliceNonce = crypto.deriveSignatureNonce(masterSecret, true);
+		byte[] aliceNonce = crypto.mac(ALICE_NONCE_LABEL, masterSecret,
-		byte[] bobNonce = crypto.deriveSignatureNonce(masterSecret, false);
+				new byte[] {PROTOCOL_VERSION});
+		byte[] bobNonce = crypto.mac(BOB_NONCE_LABEL, masterSecret,
+				new byte[] {PROTOCOL_VERSION});
 
 		// Exchange pseudonyms, signed nonces, and timestamps
 		long localTimestamp = clock.currentTimeMillis();
@@ -184,12 +188,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 			// Close the outgoing stream and expect EOF on the incoming stream
 			w.close();
 			if (!r.eof()) LOG.warning("Unexpected data at end of connection");
-		} catch (GeneralSecurityException e) {
+		} catch (GeneralSecurityException | IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			listener.contactExchangeFailed();
-			tryToClose(conn, true);
-			return;
-		} catch (IOException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			listener.contactExchangeFailed();
 			tryToClose(conn, true);
@@ -201,8 +200,8 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 
 		try {
 			// Add the contact
-			ContactId contactId = addContact(remoteAuthor, masterSecret,
+			ContactId contactId = addContact(remoteAuthor, timestamp,
-					timestamp, alice, remoteProperties);
+					remoteProperties);
 			// Reuse the connection as a transport connection
 			connectionManager.manageOutgoingConnection(contactId, transportId,
 					conn);
@@ -276,8 +275,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 
 	private Map<TransportId, TransportProperties> receiveTransportProperties(
 			BdfReader r) throws IOException {
-		Map<TransportId, TransportProperties> remote =
+		Map<TransportId, TransportProperties> remote = new HashMap<>();
-				new HashMap<TransportId, TransportProperties>();
 		r.readListStart();
 		while (!r.hasListEnd()) {
 			r.readListStart();
@@ -300,15 +298,15 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		return remote;
 	}
 
-	private ContactId addContact(Author remoteAuthor, SecretKey master,
+	private ContactId addContact(Author remoteAuthor, long timestamp,
-			long timestamp, boolean alice,
 			Map<TransportId, TransportProperties> remoteProperties)
 			throws DbException {
 		ContactId contactId;
 		Transaction txn = db.startTransaction(false);
 		try {
 			contactId = contactManager.addContact(txn, remoteAuthor,
-					localAuthor.getId(), master, timestamp, alice, true, true);
+					localAuthor.getId(), masterSecret, timestamp, alice,
+					true, true);
 			transportPropertyManager.addRemoteProperties(txn, contactId,
 					remoteProperties);
 			db.commitTransaction(txn);
@@ -318,8 +316,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		return contactId;
 	}
 
-	private void tryToClose(DuplexTransportConnection conn,
+	private void tryToClose(DuplexTransportConnection conn, boolean exception) {
-			boolean exception) {
 		try {
 			LOG.info("Closing connection");
 			conn.getReader().dispose(exception, true);

bramble-core/src/main/java/org/briarproject/bramble/contact/ContactManagerImpl.java

@@ -34,8 +34,8 @@ class ContactManagerImpl implements ContactManager {
 	ContactManagerImpl(DatabaseComponent db, KeyManager keyManager) {
 		this.db = db;
 		this.keyManager = keyManager;
-		addHooks = new CopyOnWriteArrayList<AddContactHook>();
+		addHooks = new CopyOnWriteArrayList<>();
-		removeHooks = new CopyOnWriteArrayList<RemoveContactHook>();
+		removeHooks = new CopyOnWriteArrayList<>();
 	}
 
 	@Override
@@ -125,7 +125,7 @@ class ContactManagerImpl implements ContactManager {
 		} finally {
 			db.endTransaction(txn);
 		}
-		List<Contact> active = new ArrayList<Contact>(contacts.size());
+		List<Contact> active = new ArrayList<>(contacts.size());
 		for (Contact c : contacts) if (c.isActive()) active.add(c);
 		return active;
 	}

bramble-core/src/main/java/org/briarproject/bramble/crypto/CryptoComponentImpl.java

@@ -1,16 +1,16 @@
 package org.briarproject.bramble.crypto;
 
+import net.i2p.crypto.eddsa.EdDSAPrivateKey;
+import net.i2p.crypto.eddsa.EdDSAPublicKey;
+import net.i2p.crypto.eddsa.KeyPairGenerator;
+
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.KeyPair;
 import org.briarproject.bramble.api.crypto.KeyParser;
 import org.briarproject.bramble.api.crypto.PrivateKey;
 import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.crypto.SecretKey;
-import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.system.SecureRandomProvider;
-import org.briarproject.bramble.api.transport.IncomingKeys;
-import org.briarproject.bramble.api.transport.OutgoingKeys;
-import org.briarproject.bramble.api.transport.TransportKeys;
 import org.briarproject.bramble.util.ByteUtils;
 import org.briarproject.bramble.util.StringUtils;
 import org.spongycastle.crypto.AsymmetricCipherKeyPair;
@@ -26,7 +26,6 @@ import org.spongycastle.crypto.params.ECPrivateKeyParameters;
 import org.spongycastle.crypto.params.ECPublicKeyParameters;
 import org.spongycastle.crypto.params.KeyParameter;
 
-import java.nio.charset.Charset;
 import java.security.GeneralSecurityException;
 import java.security.NoSuchAlgorithmException;
 import java.security.Provider;
@@ -40,14 +39,8 @@ import java.util.logging.Logger;
 import javax.inject.Inject;
 
 import static java.util.logging.Level.INFO;
-import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.COMMIT_LENGTH;
-import static org.briarproject.bramble.api.transport.TransportConstants.TAG_LENGTH;
 import static org.briarproject.bramble.crypto.EllipticCurveConstants.PARAMETERS;
-import static org.briarproject.bramble.util.ByteUtils.INT_16_BYTES;
 import static org.briarproject.bramble.util.ByteUtils.INT_32_BYTES;
-import static org.briarproject.bramble.util.ByteUtils.INT_64_BYTES;
-import static org.briarproject.bramble.util.ByteUtils.MAX_16_BIT_UNSIGNED;
-import static org.briarproject.bramble.util.ByteUtils.MAX_32_BIT_UNSIGNED;
 
 class CryptoComponentImpl implements CryptoComponent {
 
@@ -56,49 +49,19 @@ class CryptoComponentImpl implements CryptoComponent {
 
 	private static final int AGREEMENT_KEY_PAIR_BITS = 256;
 	private static final int SIGNATURE_KEY_PAIR_BITS = 256;
+	private static final int ED_KEY_PAIR_BITS = 256;
 	private static final int STORAGE_IV_BYTES = 24; // 196 bits
 	private static final int PBKDF_SALT_BYTES = 32; // 256 bits
 	private static final int PBKDF_TARGET_MILLIS = 500;
 	private static final int PBKDF_SAMPLES = 30;
-	private static final int HASH_SIZE = 256 / 8;
-
-	private static byte[] ascii(String s) {
-		return s.getBytes(Charset.forName("US-ASCII"));
-	}
-
-	// KDF labels for contact exchange stream header key derivation
-	private static final byte[] A_INVITE = ascii("ALICE_INVITATION_KEY");
-	private static final byte[] B_INVITE = ascii("BOB_INVITATION_KEY");
-	// KDF labels for contact exchange signature nonce derivation
-	private static final byte[] A_SIG_NONCE = ascii("ALICE_SIGNATURE_NONCE");
-	private static final byte[] B_SIG_NONCE = ascii("BOB_SIGNATURE_NONCE");
-	// Hash label for BQP public key commitment derivation
-	private static final String COMMIT =
-			"org.briarproject.bramble.COMMIT";
-	// Hash label for shared secret derivation
-	private static final String SHARED_SECRET =
-			"org.briarproject.bramble.SHARED_SECRET";
-	// KDF label for BQP confirmation key derivation
-	private static final byte[] CONFIRMATION_KEY = ascii("CONFIRMATION_KEY");
-	// KDF label for master key derivation
-	private static final byte[] MASTER_KEY = ascii("MASTER_KEY");
-	// KDF labels for tag key derivation
-	private static final byte[] A_TAG = ascii("ALICE_TAG_KEY");
-	private static final byte[] B_TAG = ascii("BOB_TAG_KEY");
-	// KDF labels for header key derivation
-	private static final byte[] A_HEADER = ascii("ALICE_HEADER_KEY");
-	private static final byte[] B_HEADER = ascii("BOB_HEADER_KEY");
-	// KDF labels for MAC key derivation
-	private static final byte[] A_MAC = ascii("ALICE_MAC_KEY");
-	private static final byte[] B_MAC = ascii("BOB_MAC_KEY");
-	// KDF label for key rotation
-	private static final byte[] ROTATE = ascii("ROTATE");
 
 	private final SecureRandom secureRandom;
 	private final ECKeyPairGenerator agreementKeyPairGenerator;
 	private final ECKeyPairGenerator signatureKeyPairGenerator;
 	private final KeyParser agreementKeyParser, signatureKeyParser;
 	private final MessageEncrypter messageEncrypter;
+	private final KeyPairGenerator edKeyPairGenerator;
+	private final KeyParser edKeyParser;
 
 	@Inject
 	CryptoComponentImpl(SecureRandomProvider secureRandomProvider) {
@@ -132,6 +95,9 @@ class CryptoComponentImpl implements CryptoComponent {
 		signatureKeyParser = new Sec1KeyParser(PARAMETERS,
 				SIGNATURE_KEY_PAIR_BITS);
 		messageEncrypter = new MessageEncrypter(secureRandom);
+		edKeyPairGenerator = new KeyPairGenerator();
+		edKeyPairGenerator.initialize(ED_KEY_PAIR_BITS, secureRandom);
+		edKeyParser = new EdKeyParser();
 	}
 
 	// Based on https://android-developers.googleblog.com/2013/08/some-securerandom-thoughts.html
@@ -190,6 +156,21 @@ class CryptoComponentImpl implements CryptoComponent {
 		return secret;
 	}
 
+	@Override
+	public KeyPair generateEdKeyPair() {
+		java.security.KeyPair keyPair = edKeyPairGenerator.generateKeyPair();
+		EdDSAPublicKey edPublicKey = (EdDSAPublicKey) keyPair.getPublic();
+		PublicKey publicKey = new EdPublicKey(edPublicKey.getAbyte());
+		EdDSAPrivateKey edPrivateKey = (EdDSAPrivateKey) keyPair.getPrivate();
+		PrivateKey privateKey = new EdPrivateKey(edPrivateKey.getSeed());
+		return new KeyPair(publicKey, privateKey);
+	}
+
+	@Override
+	public KeyParser getEdKeyParser() {
+		return edKeyParser;
+	}
+
 	@Override
 	public KeyPair generateAgreementKeyPair() {
 		AsymmetricCipherKeyPair keyPair =
@@ -238,197 +219,63 @@ class CryptoComponentImpl implements CryptoComponent {
 	}
 
 	@Override
-	public SecretKey deriveHeaderKey(SecretKey master,
+	public SecretKey deriveKey(String label, SecretKey k, byte[]... inputs) {
-			boolean alice) {
+		byte[] mac = mac(label, k, inputs);
-		return new SecretKey(macKdf(master, alice ? A_INVITE : B_INVITE));
+		if (mac.length != SecretKey.LENGTH) throw new IllegalStateException();
+		return new SecretKey(mac);
 	}
 
 	@Override
-	public SecretKey deriveMacKey(SecretKey master, boolean alice) {
+	public SecretKey deriveSharedSecret(String label, PublicKey theirPublicKey,
-		return new SecretKey(macKdf(master, alice ? A_MAC : B_MAC));
+			KeyPair ourKeyPair, byte[]... inputs)
-	}
+			throws GeneralSecurityException {
-
-	@Override
-	public byte[] deriveSignatureNonce(SecretKey master,
-			boolean alice) {
-		return macKdf(master, alice ? A_SIG_NONCE : B_SIG_NONCE);
-	}
-
-	@Override
-	public byte[] deriveKeyCommitment(byte[] publicKey) {
-		byte[] hash = hash(COMMIT, publicKey);
-		// The output is the first COMMIT_LENGTH bytes of the hash
-		byte[] commitment = new byte[COMMIT_LENGTH];
-		System.arraycopy(hash, 0, commitment, 0, COMMIT_LENGTH);
-		return commitment;
-	}
-
-	@Override
-	public SecretKey deriveSharedSecret(byte[] theirPublicKey,
-			KeyPair ourKeyPair, boolean alice) throws GeneralSecurityException {
 		PrivateKey ourPriv = ourKeyPair.getPrivate();
-		PublicKey theirPub = agreementKeyParser.parsePublicKey(theirPublicKey);
+		byte[][] hashInputs = new byte[inputs.length + 1][];
-		byte[] raw = performRawKeyAgreement(ourPriv, theirPub);
+		hashInputs[0] = performRawKeyAgreement(ourPriv, theirPublicKey);
-		byte[] alicePub, bobPub;
+		System.arraycopy(inputs, 0, hashInputs, 1, inputs.length);
-		if (alice) {
+		byte[] hash = hash(label, hashInputs);
-			alicePub = ourKeyPair.getPublic().getEncoded();
+		if (hash.length != SecretKey.LENGTH) throw new IllegalStateException();
-			bobPub = theirPublicKey;
+		return new SecretKey(hash);
-		} else {
-			alicePub = theirPublicKey;
-			bobPub = ourKeyPair.getPublic().getEncoded();
-		}
-		return new SecretKey(hash(SHARED_SECRET, raw, alicePub, bobPub));
-	}
-
-	@Override
-	public byte[] deriveConfirmationRecord(SecretKey sharedSecret,
-			byte[] theirPayload, byte[] ourPayload, byte[] theirPublicKey,
-			KeyPair ourKeyPair, boolean alice, boolean aliceRecord) {
-		SecretKey ck = new SecretKey(macKdf(sharedSecret, CONFIRMATION_KEY));
-		byte[] alicePayload, alicePub, bobPayload, bobPub;
-		if (alice) {
-			alicePayload = ourPayload;
-			alicePub = ourKeyPair.getPublic().getEncoded();
-			bobPayload = theirPayload;
-			bobPub = theirPublicKey;
-		} else {
-			alicePayload = theirPayload;
-			alicePub = theirPublicKey;
-			bobPayload = ourPayload;
-			bobPub = ourKeyPair.getPublic().getEncoded();
-		}
-		if (aliceRecord)
-			return macKdf(ck, alicePayload, alicePub, bobPayload, bobPub);
-		else
-			return macKdf(ck, bobPayload, bobPub, alicePayload, alicePub);
-	}
-
-	@Override
-	public SecretKey deriveMasterSecret(SecretKey sharedSecret) {
-		return new SecretKey(macKdf(sharedSecret, MASTER_KEY));
-	}
-
-	@Override
-	public SecretKey deriveMasterSecret(byte[] theirPublicKey,
-			KeyPair ourKeyPair, boolean alice) throws GeneralSecurityException {
-		return deriveMasterSecret(deriveSharedSecret(
-				theirPublicKey, ourKeyPair, alice));
-	}
-
-	@Override
-	public TransportKeys deriveTransportKeys(TransportId t,
-			SecretKey master, long rotationPeriod, boolean alice) {
-		// Keys for the previous period are derived from the master secret
-		SecretKey inTagPrev = deriveTagKey(master, t, !alice);
-		SecretKey inHeaderPrev = deriveHeaderKey(master, t, !alice);
-		SecretKey outTagPrev = deriveTagKey(master, t, alice);
-		SecretKey outHeaderPrev = deriveHeaderKey(master, t, alice);
-		// Derive the keys for the current and next periods
-		SecretKey inTagCurr = rotateKey(inTagPrev, rotationPeriod);
-		SecretKey inHeaderCurr = rotateKey(inHeaderPrev, rotationPeriod);
-		SecretKey inTagNext = rotateKey(inTagCurr, rotationPeriod + 1);
-		SecretKey inHeaderNext = rotateKey(inHeaderCurr, rotationPeriod + 1);
-		SecretKey outTagCurr = rotateKey(outTagPrev, rotationPeriod);
-		SecretKey outHeaderCurr = rotateKey(outHeaderPrev, rotationPeriod);
-		// Initialise the reordering windows and stream counters
-		IncomingKeys inPrev = new IncomingKeys(inTagPrev, inHeaderPrev,
-				rotationPeriod - 1);
-		IncomingKeys inCurr = new IncomingKeys(inTagCurr, inHeaderCurr,
-				rotationPeriod);
-		IncomingKeys inNext = new IncomingKeys(inTagNext, inHeaderNext,
-				rotationPeriod + 1);
-		OutgoingKeys outCurr = new OutgoingKeys(outTagCurr, outHeaderCurr,
-				rotationPeriod);
-		// Collect and return the keys
-		return new TransportKeys(t, inPrev, inCurr, inNext, outCurr);
-	}
-
-	@Override
-	public TransportKeys rotateTransportKeys(TransportKeys k,
-			long rotationPeriod) {
-		if (k.getRotationPeriod() >= rotationPeriod) return k;
-		IncomingKeys inPrev = k.getPreviousIncomingKeys();
-		IncomingKeys inCurr = k.getCurrentIncomingKeys();
-		IncomingKeys inNext = k.getNextIncomingKeys();
-		OutgoingKeys outCurr = k.getCurrentOutgoingKeys();
-		long startPeriod = outCurr.getRotationPeriod();
-		// Rotate the keys
-		for (long p = startPeriod + 1; p <= rotationPeriod; p++) {
-			inPrev = inCurr;
-			inCurr = inNext;
-			SecretKey inNextTag = rotateKey(inNext.getTagKey(), p + 1);
-			SecretKey inNextHeader = rotateKey(inNext.getHeaderKey(), p + 1);
-			inNext = new IncomingKeys(inNextTag, inNextHeader, p + 1);
-			SecretKey outCurrTag = rotateKey(outCurr.getTagKey(), p);
-			SecretKey outCurrHeader = rotateKey(outCurr.getHeaderKey(), p);
-			outCurr = new OutgoingKeys(outCurrTag, outCurrHeader, p);
-		}
-		// Collect and return the keys
-		return new TransportKeys(k.getTransportId(), inPrev, inCurr, inNext,
-				outCurr);
-	}
-
-	private SecretKey rotateKey(SecretKey k, long rotationPeriod) {
-		byte[] period = new byte[INT_64_BYTES];
-		ByteUtils.writeUint64(rotationPeriod, period, 0);
-		return new SecretKey(macKdf(k, ROTATE, period));
-	}
-
-	private SecretKey deriveTagKey(SecretKey master, TransportId t,
-			boolean alice) {
-		byte[] id = StringUtils.toUtf8(t.getString());
-		return new SecretKey(macKdf(master, alice ? A_TAG : B_TAG, id));
-	}
-
-	private SecretKey deriveHeaderKey(SecretKey master, TransportId t,
-			boolean alice) {
-		byte[] id = StringUtils.toUtf8(t.getString());
-		return new SecretKey(macKdf(master, alice ? A_HEADER : B_HEADER, id));
-	}
-
-	@Override
-	public void encodeTag(byte[] tag, SecretKey tagKey, int protocolVersion,
-			long streamNumber) {
-		if (tag.length < TAG_LENGTH) throw new IllegalArgumentException();
-		if (protocolVersion < 0 || protocolVersion > MAX_16_BIT_UNSIGNED)
-			throw new IllegalArgumentException();
-		if (streamNumber < 0 || streamNumber > MAX_32_BIT_UNSIGNED)
-			throw new IllegalArgumentException();
-		// Initialise the PRF
-		Digest prf = new Blake2sDigest(tagKey.getBytes());
-		// The output of the PRF must be long enough to use as a tag
-		int macLength = prf.getDigestSize();
-		if (macLength < TAG_LENGTH) throw new IllegalStateException();
-		// The input is the protocol version as a 16-bit integer, followed by
-		// the stream number as a 64-bit integer
-		byte[] protocolVersionBytes = new byte[INT_16_BYTES];
-		ByteUtils.writeUint16(protocolVersion, protocolVersionBytes, 0);
-		prf.update(protocolVersionBytes, 0, protocolVersionBytes.length);
-		byte[] streamNumberBytes = new byte[INT_64_BYTES];
-		ByteUtils.writeUint64(streamNumber, streamNumberBytes, 0);
-		prf.update(streamNumberBytes, 0, streamNumberBytes.length);
-		byte[] mac = new byte[macLength];
-		prf.doFinal(mac, 0);
-		// The output is the first TAG_LENGTH bytes of the MAC
-		System.arraycopy(mac, 0, tag, 0, TAG_LENGTH);
 	}
 
 	@Override
 	public byte[] sign(String label, byte[] toSign, byte[] privateKey)
 			throws GeneralSecurityException {
-		Signature signature = new SignatureImpl(secureRandom);
+		return sign(new SignatureImpl(secureRandom), signatureKeyParser, label,
-		KeyParser keyParser = getSignatureKeyParser();
+				toSign, privateKey);
+	}
+
+	@Override
+	public byte[] signEd(String label, byte[] toSign, byte[] privateKey)
+			throws GeneralSecurityException {
+		return sign(new EdSignature(), edKeyParser, label, toSign, privateKey);
+	}
+
+	private byte[] sign(Signature sig, KeyParser keyParser, String label,
+			byte[] toSign, byte[] privateKey) throws GeneralSecurityException {
 		PrivateKey key = keyParser.parsePrivateKey(privateKey);
-		signature.initSign(key);
+		sig.initSign(key);
-		updateSignature(signature, label, toSign);
+		updateSignature(sig, label, toSign);
-		return signature.sign();
+		return sig.sign();
 	}
 
 	@Override
 	public boolean verify(String label, byte[] signedData, byte[] publicKey,
 			byte[] signature) throws GeneralSecurityException {
-		Signature sig = new SignatureImpl(secureRandom);
+		return verify(new SignatureImpl(secureRandom), signatureKeyParser,
-		KeyParser keyParser = getSignatureKeyParser();
+				label, signedData, publicKey, signature);
+	}
+
+	@Override
+	public boolean verifyEd(String label, byte[] signedData, byte[] publicKey,
+			byte[] signature) throws GeneralSecurityException {
+		return verify(new EdSignature(), edKeyParser, label, signedData,
+				publicKey, signature);
+	}
+
+	private boolean verify(Signature sig, KeyParser keyParser, String label,
+			byte[] signedData, byte[] publicKey, byte[] signature)
+			throws GeneralSecurityException {
 		PublicKey key = keyParser.parsePublicKey(publicKey);
 		sig.initVerify(key);
 		updateSignature(sig, label, signedData);
@@ -436,7 +283,7 @@ class CryptoComponentImpl implements CryptoComponent {
 	}
 
 	private void updateSignature(Signature signature, String label,
-			byte[] toSign) {
+			byte[] toSign) throws GeneralSecurityException {
 		byte[] labelBytes = StringUtils.toUtf8(label);
 		byte[] length = new byte[INT_32_BYTES];
 		ByteUtils.writeUint32(labelBytes.length, length, 0);
@@ -466,14 +313,13 @@ class CryptoComponentImpl implements CryptoComponent {
 	}
 
 	@Override
-	public int getHashLength() {
+	public byte[] mac(String label, SecretKey macKey, byte[]... inputs) {
-		return HASH_SIZE;
+		byte[] labelBytes = StringUtils.toUtf8(label);
-	}
-
-	@Override
-	public byte[] mac(SecretKey macKey, byte[]... inputs) {
 		Digest mac = new Blake2sDigest(macKey.getBytes());
 		byte[] length = new byte[INT_32_BYTES];
+		ByteUtils.writeUint32(labelBytes.length, length, 0);
+		mac.update(length, 0, length.length);
+		mac.update(labelBytes, 0, labelBytes.length);
 		for (byte[] input : inputs) {
 			ByteUtils.writeUint32(input.length, length, 0);
 			mac.update(length, 0, length.length);
@@ -565,30 +411,6 @@ class CryptoComponentImpl implements CryptoComponent {
 		return AsciiArmour.wrap(b, lineLength);
 	}
 
-	// Key derivation function based on a pseudo-random function - see
-	// NIST SP 800-108, section 5.1
-	private byte[] macKdf(SecretKey key, byte[]... inputs) {
-		// Initialise the PRF
-		Digest prf = new Blake2sDigest(key.getBytes());
-		// The output of the PRF must be long enough to use as a key
-		int macLength = prf.getDigestSize();
-		if (macLength < SecretKey.LENGTH) throw new IllegalStateException();
-		// Calculate the PRF over the concatenated length-prefixed inputs
-		byte[] length = new byte[INT_32_BYTES];
-		for (byte[] input : inputs) {
-			ByteUtils.writeUint32(input.length, length, 0);
-			prf.update(length, 0, length.length);
-			prf.update(input, 0, input.length);
-		}
-		byte[] mac = new byte[macLength];
-		prf.doFinal(mac, 0);
-		// The output is the first SecretKey.LENGTH bytes of the MAC
-		if (mac.length == SecretKey.LENGTH) return mac;
-		byte[] truncated = new byte[SecretKey.LENGTH];
-		System.arraycopy(mac, 0, truncated, 0, truncated.length);
-		return truncated;
-	}
-
 	// Password-based key derivation function - see PKCS#5 v2.1, section 5.2
 	private byte[] pbkdf2(String password, byte[] salt, int iterations) {
 		byte[] utf8 = StringUtils.toUtf8(password);
@@ -602,8 +424,8 @@ class CryptoComponentImpl implements CryptoComponent {
 
 	// Package access for testing
 	int chooseIterationCount(int targetMillis) {
-		List<Long> quickSamples = new ArrayList<Long>(PBKDF_SAMPLES);
+		List<Long> quickSamples = new ArrayList<>(PBKDF_SAMPLES);
-		List<Long> slowSamples = new ArrayList<Long>(PBKDF_SAMPLES);
+		List<Long> slowSamples = new ArrayList<>(PBKDF_SAMPLES);
 		long iterationNanos = 0, initNanos = 0;
 		while (iterationNanos <= 0 || initNanos <= 0) {
 			// Sample the running time with one iteration and two iterations

bramble-core/src/main/java/org/briarproject/bramble/crypto/CryptoModule.java

@@ -3,9 +3,11 @@ package org.briarproject.bramble.crypto;
 import org.briarproject.bramble.TimeLoggingExecutor;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.CryptoExecutor;
+import org.briarproject.bramble.api.crypto.KeyAgreementCrypto;
 import org.briarproject.bramble.api.crypto.PasswordStrengthEstimator;
 import org.briarproject.bramble.api.crypto.StreamDecrypterFactory;
 import org.briarproject.bramble.api.crypto.StreamEncrypterFactory;
+import org.briarproject.bramble.api.crypto.TransportCrypto;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.system.SecureRandomProvider;
 
@@ -48,7 +50,7 @@ public class CryptoModule {
 
 	public CryptoModule() {
 		// Use an unbounded queue
-		BlockingQueue<Runnable> queue = new LinkedBlockingQueue<Runnable>();
+		BlockingQueue<Runnable> queue = new LinkedBlockingQueue<>();
 		// Discard tasks that are submitted during shutdown
 		RejectedExecutionHandler policy =
 				new ThreadPoolExecutor.DiscardPolicy();
@@ -74,6 +76,12 @@ public class CryptoModule {
 		return new PasswordStrengthEstimatorImpl();
 	}
 
+	@Provides
+	TransportCrypto provideTransportCrypto(
+			TransportCryptoImpl transportCrypto) {
+		return transportCrypto;
+	}
+
 	@Provides
 	StreamDecrypterFactory provideStreamDecrypterFactory(
 			Provider<AuthenticatedCipher> cipherProvider) {
@@ -81,9 +89,17 @@ public class CryptoModule {
 	}
 
 	@Provides
-	StreamEncrypterFactory provideStreamEncrypterFactory(CryptoComponent crypto,
+	StreamEncrypterFactory provideStreamEncrypterFactory(
+			CryptoComponent crypto, TransportCrypto transportCrypto,
 			Provider<AuthenticatedCipher> cipherProvider) {
-		return new StreamEncrypterFactoryImpl(crypto, cipherProvider);
+		return new StreamEncrypterFactoryImpl(crypto, transportCrypto,
+				cipherProvider);
+	}
+
+	@Provides
+	KeyAgreementCrypto provideKeyAgreementCrypto(
+			KeyAgreementCryptoImpl keyAgreementCrypto) {
+		return keyAgreementCrypto;
 	}
 
 	@Provides

bramble-core/src/main/java/org/briarproject/bramble/crypto/EdKeyParser.java

@@ -0,0 +1,26 @@
+package org.briarproject.bramble.crypto;
+
+import org.briarproject.bramble.api.crypto.KeyParser;
+import org.briarproject.bramble.api.crypto.PrivateKey;
+import org.briarproject.bramble.api.crypto.PublicKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.security.GeneralSecurityException;
+
+@NotNullByDefault
+class EdKeyParser implements KeyParser {
+
+	@Override
+	public PublicKey parsePublicKey(byte[] encodedKey)
+			throws GeneralSecurityException {
+		if (encodedKey.length != 32) throw new GeneralSecurityException();
+		return new EdPublicKey(encodedKey);
+	}
+
+	@Override
+	public PrivateKey parsePrivateKey(byte[] encodedKey)
+			throws GeneralSecurityException {
+		if (encodedKey.length != 32) throw new GeneralSecurityException();
+		return new EdPrivateKey(encodedKey);
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/crypto/EdPrivateKey.java

@@ -0,0 +1,18 @@
+package org.briarproject.bramble.crypto;
+
+import org.briarproject.bramble.api.Bytes;
+import org.briarproject.bramble.api.crypto.PrivateKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+class EdPrivateKey extends Bytes implements PrivateKey {
+
+	EdPrivateKey(byte[] bytes) {
+		super(bytes);
+	}
+
+	@Override
+	public byte[] getEncoded() {
+		return getBytes();
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/crypto/EdPublicKey.java

@@ -0,0 +1,18 @@
+package org.briarproject.bramble.crypto;
+
+import org.briarproject.bramble.api.Bytes;
+import org.briarproject.bramble.api.crypto.PublicKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+class EdPublicKey extends Bytes implements PublicKey {
+
+	EdPublicKey(byte[] bytes) {
+		super(bytes);
+	}
+
+	@Override
+	public byte[] getEncoded() {
+		return getBytes();
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/crypto/EdSignature.java

@@ -0,0 +1,83 @@
+package org.briarproject.bramble.crypto;
+
+import net.i2p.crypto.eddsa.EdDSAPrivateKey;
+import net.i2p.crypto.eddsa.EdDSAPublicKey;
+import net.i2p.crypto.eddsa.EdDSASecurityProvider;
+import net.i2p.crypto.eddsa.spec.EdDSANamedCurveSpec;
+import net.i2p.crypto.eddsa.spec.EdDSANamedCurveTable;
+import net.i2p.crypto.eddsa.spec.EdDSAPrivateKeySpec;
+import net.i2p.crypto.eddsa.spec.EdDSAPublicKeySpec;
+
+import org.briarproject.bramble.api.crypto.PrivateKey;
+import org.briarproject.bramble.api.crypto.PublicKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.security.GeneralSecurityException;
+import java.security.NoSuchAlgorithmException;
+import java.security.Provider;
+
+import static net.i2p.crypto.eddsa.EdDSAEngine.SIGNATURE_ALGORITHM;
+
+@NotNullByDefault
+class EdSignature implements Signature {
+
+	private static final Provider PROVIDER = new EdDSASecurityProvider();
+
+	private static final EdDSANamedCurveSpec CURVE_SPEC =
+			EdDSANamedCurveTable.getByName("Ed25519");
+
+	private final java.security.Signature signature;
+
+	EdSignature() {
+		try {
+			signature = java.security.Signature
+					.getInstance(SIGNATURE_ALGORITHM, PROVIDER);
+		} catch (NoSuchAlgorithmException e) {
+			throw new AssertionError(e);
+		}
+	}
+
+	@Override
+	public void initSign(PrivateKey k) throws GeneralSecurityException {
+		if (!(k instanceof EdPrivateKey))
+			throw new IllegalArgumentException();
+		EdDSAPrivateKey privateKey = new EdDSAPrivateKey(
+				new EdDSAPrivateKeySpec(k.getEncoded(), CURVE_SPEC));
+		signature.initSign(privateKey);
+	}
+
+	@Override
+	public void initVerify(PublicKey k) throws GeneralSecurityException {
+		if (!(k instanceof EdPublicKey))
+			throw new IllegalArgumentException();
+		EdDSAPublicKey publicKey = new EdDSAPublicKey(
+				new EdDSAPublicKeySpec(k.getEncoded(), CURVE_SPEC));
+		signature.initVerify(publicKey);
+	}
+
+	@Override
+	public void update(byte b) throws GeneralSecurityException {
+		signature.update(b);
+	}
+
+	@Override
+	public void update(byte[] b) throws GeneralSecurityException {
+		signature.update(b);
+	}
+
+	@Override
+	public void update(byte[] b, int off, int len)
+			throws GeneralSecurityException {
+		signature.update(b, off, len);
+	}
+
+	@Override
+	public byte[] sign() throws GeneralSecurityException {
+		return signature.sign();
+	}
+
+	@Override
+	public boolean verify(byte[] sig) throws GeneralSecurityException {
+		return signature.verify(sig);
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/crypto/KeyAgreementCryptoImpl.java

@@ -0,0 +1,56 @@
+package org.briarproject.bramble.crypto;
+
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.KeyAgreementCrypto;
+import org.briarproject.bramble.api.crypto.KeyPair;
+import org.briarproject.bramble.api.crypto.PublicKey;
+import org.briarproject.bramble.api.crypto.SecretKey;
+
+import javax.inject.Inject;
+
+import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.COMMIT_LENGTH;
+
+class KeyAgreementCryptoImpl implements KeyAgreementCrypto {
+
+	private final CryptoComponent crypto;
+
+	@Inject
+	KeyAgreementCryptoImpl(CryptoComponent crypto) {
+		this.crypto = crypto;
+	}
+
+	@Override
+	public byte[] deriveKeyCommitment(PublicKey publicKey) {
+		byte[] hash = crypto.hash(COMMIT_LABEL, publicKey.getEncoded());
+		// The output is the first COMMIT_LENGTH bytes of the hash
+		byte[] commitment = new byte[COMMIT_LENGTH];
+		System.arraycopy(hash, 0, commitment, 0, COMMIT_LENGTH);
+		return commitment;
+	}
+
+	@Override
+	public byte[] deriveConfirmationRecord(SecretKey sharedSecret,
+			byte[] theirPayload, byte[] ourPayload, PublicKey theirPublicKey,
+			KeyPair ourKeyPair, boolean alice, boolean aliceRecord) {
+		SecretKey ck = crypto.deriveKey(CONFIRMATION_KEY_LABEL, sharedSecret);
+		byte[] alicePayload, alicePub, bobPayload, bobPub;
+		if (alice) {
+			alicePayload = ourPayload;
+			alicePub = ourKeyPair.getPublic().getEncoded();
+			bobPayload = theirPayload;
+			bobPub = theirPublicKey.getEncoded();
+		} else {
+			alicePayload = theirPayload;
+			alicePub = theirPublicKey.getEncoded();
+			bobPayload = ourPayload;
+			bobPub = ourKeyPair.getPublic().getEncoded();
+		}
+		if (aliceRecord) {
+			return crypto.mac(CONFIRMATION_MAC_LABEL, ck, alicePayload,
+					alicePub, bobPayload, bobPub);
+		} else {
+			return crypto.mac(CONFIRMATION_MAC_LABEL, ck, bobPayload, bobPub,
+					alicePayload, alicePub);
+		}
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/crypto/PasswordStrengthEstimatorImpl.java

@@ -16,7 +16,7 @@ class PasswordStrengthEstimatorImpl implements PasswordStrengthEstimator {
 
 	@Override
 	public float estimateStrength(String password) {
-		HashSet<Character> unique = new HashSet<Character>();
+		HashSet<Character> unique = new HashSet<>();
 		int length = password.length();
 		for (int i = 0; i < length; i++) unique.add(password.charAt(i));
 		return Math.min(1, (float) unique.size() / STRONG_UNIQUE_CHARS);

bramble-core/src/main/java/org/briarproject/bramble/crypto/Signature.java

@@ -22,25 +22,25 @@ interface Signature {
 	/**
 	 * @see {@link java.security.Signature#update(byte)}
 	 */
-	void update(byte b);
+	void update(byte b) throws GeneralSecurityException;
 
 	/**
 	 * @see {@link java.security.Signature#update(byte[])}
 	 */
-	void update(byte[] b);
+	void update(byte[] b) throws GeneralSecurityException;
 
 	/**
 	 * @see {@link java.security.Signature#update(byte[], int, int)}
 	 */
-	void update(byte[] b, int off, int len);
+	void update(byte[] b, int off, int len) throws GeneralSecurityException;
 
 	/**
 	 * @see {@link java.security.Signature#sign()}
 	 */
-	byte[] sign();
+	byte[] sign() throws GeneralSecurityException;
 
 	/**
 	 * @see {@link java.security.Signature#verify(byte[])}
 	 */
-	boolean verify(byte[] signature);
+	boolean verify(byte[] signature) throws GeneralSecurityException;
 }

bramble-core/src/main/java/org/briarproject/bramble/crypto/StreamEncrypterFactoryImpl.java

@@ -4,6 +4,7 @@ import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.crypto.StreamEncrypter;
 import org.briarproject.bramble.api.crypto.StreamEncrypterFactory;
+import org.briarproject.bramble.api.crypto.TransportCrypto;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.transport.StreamContext;
 
@@ -22,12 +23,15 @@ import static org.briarproject.bramble.api.transport.TransportConstants.TAG_LENG
 class StreamEncrypterFactoryImpl implements StreamEncrypterFactory {
 
 	private final CryptoComponent crypto;
+	private final TransportCrypto transportCrypto;
 	private final Provider<AuthenticatedCipher> cipherProvider;
 
 	@Inject
 	StreamEncrypterFactoryImpl(CryptoComponent crypto,
+			TransportCrypto transportCrypto,
 			Provider<AuthenticatedCipher> cipherProvider) {
 		this.crypto = crypto;
+		this.transportCrypto = transportCrypto;
 		this.cipherProvider = cipherProvider;
 	}
 
@@ -37,7 +41,8 @@ class StreamEncrypterFactoryImpl implements StreamEncrypterFactory {
 		AuthenticatedCipher cipher = cipherProvider.get();
 		long streamNumber = ctx.getStreamNumber();
 		byte[] tag = new byte[TAG_LENGTH];
-		crypto.encodeTag(tag, ctx.getTagKey(), PROTOCOL_VERSION, streamNumber);
+		transportCrypto.encodeTag(tag, ctx.getTagKey(), PROTOCOL_VERSION,
+				streamNumber);
 		byte[] streamHeaderNonce = new byte[STREAM_HEADER_NONCE_LENGTH];
 		crypto.getSecureRandom().nextBytes(streamHeaderNonce);
 		SecretKey frameKey = crypto.generateSecretKey();

bramble-core/src/main/java/org/briarproject/bramble/crypto/TransportCryptoImpl.java

@@ -0,0 +1,135 @@
+package org.briarproject.bramble.crypto;
+
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.crypto.TransportCrypto;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.transport.IncomingKeys;
+import org.briarproject.bramble.api.transport.OutgoingKeys;
+import org.briarproject.bramble.api.transport.TransportKeys;
+import org.briarproject.bramble.util.ByteUtils;
+import org.briarproject.bramble.util.StringUtils;
+import org.spongycastle.crypto.Digest;
+
+import javax.inject.Inject;
+
+import static org.briarproject.bramble.api.transport.TransportConstants.ALICE_HEADER_LABEL;
+import static org.briarproject.bramble.api.transport.TransportConstants.ALICE_TAG_LABEL;
+import static org.briarproject.bramble.api.transport.TransportConstants.BOB_HEADER_LABEL;
+import static org.briarproject.bramble.api.transport.TransportConstants.BOB_TAG_LABEL;
+import static org.briarproject.bramble.api.transport.TransportConstants.ROTATE_LABEL;
+import static org.briarproject.bramble.api.transport.TransportConstants.TAG_LENGTH;
+import static org.briarproject.bramble.util.ByteUtils.INT_16_BYTES;
+import static org.briarproject.bramble.util.ByteUtils.INT_64_BYTES;
+import static org.briarproject.bramble.util.ByteUtils.MAX_16_BIT_UNSIGNED;
+import static org.briarproject.bramble.util.ByteUtils.MAX_32_BIT_UNSIGNED;
+
+class TransportCryptoImpl implements TransportCrypto {
+
+	private final CryptoComponent crypto;
+
+	@Inject
+	TransportCryptoImpl(CryptoComponent crypto) {
+		this.crypto = crypto;
+	}
+
+	@Override
+	public TransportKeys deriveTransportKeys(TransportId t,
+			SecretKey master, long rotationPeriod, boolean alice) {
+		// Keys for the previous period are derived from the master secret
+		SecretKey inTagPrev = deriveTagKey(master, t, !alice);
+		SecretKey inHeaderPrev = deriveHeaderKey(master, t, !alice);
+		SecretKey outTagPrev = deriveTagKey(master, t, alice);
+		SecretKey outHeaderPrev = deriveHeaderKey(master, t, alice);
+		// Derive the keys for the current and next periods
+		SecretKey inTagCurr = rotateKey(inTagPrev, rotationPeriod);
+		SecretKey inHeaderCurr = rotateKey(inHeaderPrev, rotationPeriod);
+		SecretKey inTagNext = rotateKey(inTagCurr, rotationPeriod + 1);
+		SecretKey inHeaderNext = rotateKey(inHeaderCurr, rotationPeriod + 1);
+		SecretKey outTagCurr = rotateKey(outTagPrev, rotationPeriod);
+		SecretKey outHeaderCurr = rotateKey(outHeaderPrev, rotationPeriod);
+		// Initialise the reordering windows and stream counters
+		IncomingKeys inPrev = new IncomingKeys(inTagPrev, inHeaderPrev,
+				rotationPeriod - 1);
+		IncomingKeys inCurr = new IncomingKeys(inTagCurr, inHeaderCurr,
+				rotationPeriod);
+		IncomingKeys inNext = new IncomingKeys(inTagNext, inHeaderNext,
+				rotationPeriod + 1);
+		OutgoingKeys outCurr = new OutgoingKeys(outTagCurr, outHeaderCurr,
+				rotationPeriod);
+		// Collect and return the keys
+		return new TransportKeys(t, inPrev, inCurr, inNext, outCurr);
+	}
+
+	@Override
+	public TransportKeys rotateTransportKeys(TransportKeys k,
+			long rotationPeriod) {
+		if (k.getRotationPeriod() >= rotationPeriod) return k;
+		IncomingKeys inPrev = k.getPreviousIncomingKeys();
+		IncomingKeys inCurr = k.getCurrentIncomingKeys();
+		IncomingKeys inNext = k.getNextIncomingKeys();
+		OutgoingKeys outCurr = k.getCurrentOutgoingKeys();
+		long startPeriod = outCurr.getRotationPeriod();
+		// Rotate the keys
+		for (long p = startPeriod + 1; p <= rotationPeriod; p++) {
+			inPrev = inCurr;
+			inCurr = inNext;
+			SecretKey inNextTag = rotateKey(inNext.getTagKey(), p + 1);
+			SecretKey inNextHeader = rotateKey(inNext.getHeaderKey(), p + 1);
+			inNext = new IncomingKeys(inNextTag, inNextHeader, p + 1);
+			SecretKey outCurrTag = rotateKey(outCurr.getTagKey(), p);
+			SecretKey outCurrHeader = rotateKey(outCurr.getHeaderKey(), p);
+			outCurr = new OutgoingKeys(outCurrTag, outCurrHeader, p);
+		}
+		// Collect and return the keys
+		return new TransportKeys(k.getTransportId(), inPrev, inCurr, inNext,
+				outCurr);
+	}
+
+	private SecretKey rotateKey(SecretKey k, long rotationPeriod) {
+		byte[] period = new byte[INT_64_BYTES];
+		ByteUtils.writeUint64(rotationPeriod, period, 0);
+		return crypto.deriveKey(ROTATE_LABEL, k, period);
+	}
+
+	private SecretKey deriveTagKey(SecretKey master, TransportId t,
+			boolean alice) {
+		String label = alice ? ALICE_TAG_LABEL : BOB_TAG_LABEL;
+		byte[] id = StringUtils.toUtf8(t.getString());
+		return crypto.deriveKey(label, master, id);
+	}
+
+	private SecretKey deriveHeaderKey(SecretKey master, TransportId t,
+			boolean alice) {
+		String label = alice ? ALICE_HEADER_LABEL : BOB_HEADER_LABEL;
+		byte[] id = StringUtils.toUtf8(t.getString());
+		return crypto.deriveKey(label, master, id);
+	}
+
+	@Override
+	public void encodeTag(byte[] tag, SecretKey tagKey, int protocolVersion,
+			long streamNumber) {
+		if (tag.length < TAG_LENGTH) throw new IllegalArgumentException();
+		if (protocolVersion < 0 || protocolVersion > MAX_16_BIT_UNSIGNED)
+			throw new IllegalArgumentException();
+		if (streamNumber < 0 || streamNumber > MAX_32_BIT_UNSIGNED)
+			throw new IllegalArgumentException();
+		// Initialise the PRF
+		Digest prf = new Blake2sDigest(tagKey.getBytes());
+		// The output of the PRF must be long enough to use as a tag
+		int macLength = prf.getDigestSize();
+		if (macLength < TAG_LENGTH) throw new IllegalStateException();
+		// The input is the protocol version as a 16-bit integer, followed by
+		// the stream number as a 64-bit integer
+		byte[] protocolVersionBytes = new byte[INT_16_BYTES];
+		ByteUtils.writeUint16(protocolVersion, protocolVersionBytes, 0);
+		prf.update(protocolVersionBytes, 0, protocolVersionBytes.length);
+		byte[] streamNumberBytes = new byte[INT_64_BYTES];
+		ByteUtils.writeUint64(streamNumber, streamNumberBytes, 0);
+		prf.update(streamNumberBytes, 0, streamNumberBytes.length);
+		byte[] mac = new byte[macLength];
+		prf.doFinal(mac, 0);
+		// The output is the first TAG_LENGTH bytes of the MAC
+		System.arraycopy(mac, 0, tag, 0, TAG_LENGTH);
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseComponentImpl.java

@@ -90,8 +90,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	private final ReentrantReadWriteLock lock =
 			new ReentrantReadWriteLock(true);
 
-	private volatile int shutdownHandle = -1;
-
 	@Inject
 	DatabaseComponentImpl(Database<T> db, Class<T> txnClass, EventBus eventBus,
 			ShutdownManager shutdown) {
@@ -103,26 +101,20 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 
 	@Override
 	public boolean open() throws DbException {
-		Runnable shutdownHook = new Runnable() {
-			@Override
-			public void run() {
-				try {
-					close();
-				} catch (DbException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
-				}
-			}
-		};
 		boolean reopened = db.open();
-		shutdownHandle = shutdown.addShutdownHook(shutdownHook);
+		shutdown.addShutdownHook(() -> {
+			try {
+				close();
+			} catch (DbException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+			}
+		});
 		return reopened;
 	}
 
 	@Override
 	public void close() throws DbException {
 		if (closed.getAndSet(true)) return;
-		shutdown.removeShutdownHook(shutdownHandle);
 		db.close();
 	}
 
@@ -141,11 +133,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		}
 		try {
 			return new Transaction(db.startTransaction(), readOnly);
-		} catch (DbException e) {
+		} catch (DbException | RuntimeException e) {
-			if (readOnly) lock.readLock().unlock();
-			else lock.writeLock().unlock();
-			throw e;
-		} catch (RuntimeException e) {
 			if (readOnly) lock.readLock().unlock();
 			else lock.writeLock().unlock();
 			throw e;
@@ -331,7 +319,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		if (!db.containsContact(txn, c))
 			throw new NoSuchContactException();
 		Collection<MessageId> ids = db.getMessagesToSend(txn, c, maxLength);
-		List<byte[]> messages = new ArrayList<byte[]>(ids.size());
+		List<byte[]> messages = new ArrayList<>(ids.size());
 		for (MessageId m : ids) {
 			messages.add(db.getRawMessage(txn, m));
 			db.updateExpiryTime(txn, c, m, maxLatency);
@@ -381,7 +369,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			throw new NoSuchContactException();
 		Collection<MessageId> ids = db.getRequestedMessagesToSend(txn, c,
 				maxLength);
-		List<byte[]> messages = new ArrayList<byte[]>(ids.size());
+		List<byte[]> messages = new ArrayList<>(ids.size());
 		for (MessageId m : ids) {
 			messages.add(db.getRawMessage(txn, m));
 			db.updateExpiryTime(txn, c, m, maxLatency);
@@ -661,7 +649,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		T txn = unbox(transaction);
 		if (!db.containsContact(txn, c))
 			throw new NoSuchContactException();
-		Collection<MessageId> acked = new ArrayList<MessageId>();
+		Collection<MessageId> acked = new ArrayList<>();
 		for (MessageId m : a.getMessageIds()) {
 			if (db.containsVisibleMessage(txn, c, m)) {
 				db.raiseSeenFlag(txn, c, m);
@@ -770,6 +758,16 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		transaction.attach(new LocalAuthorRemovedEvent(a));
 	}
 
+	@Override
+	public void removeMessage(Transaction transaction, MessageId m)
+			throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsMessage(txn, m))
+			throw new NoSuchMessageException();
+		db.removeMessage(txn, m);
+	}
+
 	@Override
 	public void removeTransport(Transaction transaction, TransportId t)
 			throws DbException {
@@ -886,8 +884,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			Map<ContactId, TransportKeys> keys) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
-		Map<ContactId, TransportKeys> filtered =
+		Map<ContactId, TransportKeys> filtered = new HashMap<>();
-				new HashMap<ContactId, TransportKeys>();
 		for (Entry<ContactId, TransportKeys> e : keys.entrySet()) {
 			ContactId c = e.getKey();
 			TransportKeys k = e.getValue();

bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseExecutorModule.java

@@ -32,7 +32,7 @@ public class DatabaseExecutorModule {
 
 	public DatabaseExecutorModule() {
 		// Use an unbounded queue
-		BlockingQueue<Runnable> queue = new LinkedBlockingQueue<Runnable>();
+		BlockingQueue<Runnable> queue = new LinkedBlockingQueue<>();
 		// Discard tasks that are submitted during shutdown
 		RejectedExecutionHandler policy =
 				new ThreadPoolExecutor.DiscardPolicy();

bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseModule.java

@@ -26,7 +26,7 @@ public class DatabaseModule {
 	@Singleton
 	DatabaseComponent provideDatabaseComponent(Database<Connection> db,
 			EventBus eventBus, ShutdownManager shutdown) {
-		return new DatabaseComponentImpl<Connection>(db, Connection.class,
+		return new DatabaseComponentImpl<>(db, Connection.class, eventBus,
-				eventBus, shutdown);
+				shutdown);
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/db/H2Database.java

@@ -22,21 +22,23 @@ import javax.inject.Inject;
 class H2Database extends JdbcDatabase {
 
 	private static final String HASH_TYPE = "BINARY(32)";
+	private static final String SECRET_TYPE = "BINARY(32)";
 	private static final String BINARY_TYPE = "BINARY";
 	private static final String COUNTER_TYPE = "INT NOT NULL AUTO_INCREMENT";
-	private static final String SECRET_TYPE = "BINARY(32)";
+	private static final String STRING_TYPE = "VARCHAR";
 
 	private final DatabaseConfig config;
 	private final String url;
 
 	@Inject
 	H2Database(DatabaseConfig config, Clock clock) {
-		super(HASH_TYPE, BINARY_TYPE, COUNTER_TYPE, SECRET_TYPE, clock);
+		super(HASH_TYPE, SECRET_TYPE, BINARY_TYPE, COUNTER_TYPE, STRING_TYPE,
+				clock);
 		this.config = config;
 		File dir = config.getDatabaseDirectory();
 		String path = new File(dir, "db").getAbsolutePath();
 		url = "jdbc:h2:split:" + path + ";CIPHER=AES;MULTI_THREADED=1"
-				+ ";WRITE_DELAY=0;DB_CLOSE_ON_EXIT=false";
+				+ ";WRITE_DELAY=0";
 	}
 
 	@Override

bramble-core/src/main/java/org/briarproject/bramble/db/HyperSqlDatabase.java

@@ -0,0 +1,99 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.db.DatabaseConfig;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.util.StringUtils;
+
+import java.io.File;
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+import java.sql.Statement;
+
+import javax.inject.Inject;
+
+/**
+ * Contains all the HSQLDB-specific code for the database.
+ */
+@NotNullByDefault
+class HyperSqlDatabase extends JdbcDatabase {
+
+	private static final String HASH_TYPE = "BINARY(32)";
+	private static final String SECRET_TYPE = "BINARY(32)";
+	private static final String BINARY_TYPE = "BINARY";
+	private static final String COUNTER_TYPE =
+			"INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY(START WITH 1)";
+	private static final String STRING_TYPE = "VARCHAR";
+
+	private final DatabaseConfig config;
+	private final String url;
+
+	@Inject
+	HyperSqlDatabase(DatabaseConfig config, Clock clock) {
+		super(HASH_TYPE, SECRET_TYPE, BINARY_TYPE, COUNTER_TYPE, STRING_TYPE,
+				clock);
+		this.config = config;
+		File dir = config.getDatabaseDirectory();
+		String path = new File(dir, "db").getAbsolutePath();
+		url = "jdbc:hsqldb:file:" + path
+				+ ";sql.enforce_size=false;allow_empty_batch=true"
+				+ ";encrypt_lobs=true;crypt_type=AES";
+	}
+
+	@Override
+	public boolean open() throws DbException {
+		boolean reopen = config.databaseExists();
+		if (!reopen) config.getDatabaseDirectory().mkdirs();
+		super.open("org.hsqldb.jdbc.JDBCDriver", reopen);
+		return reopen;
+	}
+
+	@Override
+	public void close() throws DbException {
+		try {
+			super.closeAllConnections();
+			Connection c = createConnection();
+			Statement s = c.createStatement();
+			s.executeQuery("SHUTDOWN");
+			s.close();
+			c.close();
+		} catch (SQLException e) {
+			throw new DbException(e);
+		}
+	}
+
+	@Override
+	public long getFreeSpace() throws DbException {
+		File dir = config.getDatabaseDirectory();
+		long maxSize = config.getMaxSize();
+		long free = dir.getFreeSpace();
+		long used = getDiskSpace(dir);
+		long quota = maxSize - used;
+		return Math.min(free, quota);
+	}
+
+	private long getDiskSpace(File f) {
+		if (f.isDirectory()) {
+			long total = 0;
+			File[] children = f.listFiles();
+			if (children != null)
+				for (File child : children) total += getDiskSpace(child);
+			return total;
+		} else if (f.isFile()) {
+			return f.length();
+		} else {
+			return 0;
+		}
+	}
+
+	@Override
+	protected Connection createConnection() throws SQLException {
+		SecretKey key = config.getEncryptionKey();
+		if (key == null) throw new IllegalStateException();
+		String hex = StringUtils.toHexString(key.getBytes());
+		return DriverManager.getConnection(url + ";crypt_key=" + hex);
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/db/JdbcDatabase.java

@@ -68,32 +68,32 @@ import static org.briarproject.bramble.db.ExponentialBackoff.calculateExpiry;
 @NotNullByDefault
 abstract class JdbcDatabase implements Database<Connection> {
 
-	private static final int SCHEMA_VERSION = 30;
+	private static final int SCHEMA_VERSION = 31;
-	private static final int MIN_SCHEMA_VERSION = 30;
+	private static final int MIN_SCHEMA_VERSION = 31;
 
 	private static final String CREATE_SETTINGS =
 			"CREATE TABLE settings"
-					+ " (namespace VARCHAR NOT NULL,"
+					+ " (namespace _STRING NOT NULL,"
-					+ " key VARCHAR NOT NULL,"
+					+ " settingKey _STRING NOT NULL,"
-					+ " value VARCHAR NOT NULL,"
+					+ " value _STRING NOT NULL,"
-					+ " PRIMARY KEY (namespace, key))";
+					+ " PRIMARY KEY (namespace, settingKey))";
 
 	private static final String CREATE_LOCAL_AUTHORS =
 			"CREATE TABLE localAuthors"
-					+ " (authorId HASH NOT NULL,"
+					+ " (authorId _HASH NOT NULL,"
-					+ " name VARCHAR NOT NULL,"
+					+ " name _STRING NOT NULL,"
-					+ " publicKey BINARY NOT NULL,"
+					+ " publicKey _BINARY NOT NULL,"
-					+ " privateKey BINARY NOT NULL,"
+					+ " privateKey _BINARY NOT NULL,"
 					+ " created BIGINT NOT NULL,"
 					+ " PRIMARY KEY (authorId))";
 
 	private static final String CREATE_CONTACTS =
 			"CREATE TABLE contacts"
-					+ " (contactId COUNTER,"
+					+ " (contactId _COUNTER,"
-					+ " authorId HASH NOT NULL,"
+					+ " authorId _HASH NOT NULL,"
-					+ " name VARCHAR NOT NULL,"
+					+ " name _STRING NOT NULL,"
-					+ " publicKey BINARY NOT NULL,"
+					+ " publicKey _BINARY NOT NULL,"
-					+ " localAuthorId HASH NOT NULL,"
+					+ " localAuthorId _HASH NOT NULL,"
 					+ " verified BOOLEAN NOT NULL,"
 					+ " active BOOLEAN NOT NULL,"
 					+ " PRIMARY KEY (contactId),"
@@ -103,17 +103,17 @@ abstract class JdbcDatabase implements Database<Connection> {
 
 	private static final String CREATE_GROUPS =
 			"CREATE TABLE groups"
-					+ " (groupId HASH NOT NULL,"
+					+ " (groupId _HASH NOT NULL,"
-					+ " clientId VARCHAR NOT NULL,"
+					+ " clientId _STRING NOT NULL,"
-					+ " descriptor BINARY NOT NULL,"
+					+ " descriptor _BINARY NOT NULL,"
 					+ " PRIMARY KEY (groupId))";
 
 	private static final String CREATE_GROUP_METADATA =
 			"CREATE TABLE groupMetadata"
-					+ " (groupId HASH NOT NULL,"
+					+ " (groupId _HASH NOT NULL,"
-					+ " key VARCHAR NOT NULL,"
+					+ " metaKey _STRING NOT NULL,"
-					+ " value BINARY NOT NULL,"
+					+ " value _BINARY NOT NULL,"
-					+ " PRIMARY KEY (groupId, key),"
+					+ " PRIMARY KEY (groupId, metaKey),"
 					+ " FOREIGN KEY (groupId)"
 					+ " REFERENCES groups (groupId)"
 					+ " ON DELETE CASCADE)";
@@ -121,7 +121,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	private static final String CREATE_GROUP_VISIBILITIES =
 			"CREATE TABLE groupVisibilities"
 					+ " (contactId INT NOT NULL,"
-					+ " groupId HASH NOT NULL,"
+					+ " groupId _HASH NOT NULL,"
 					+ " shared BOOLEAN NOT NULL,"
 					+ " PRIMARY KEY (contactId, groupId),"
 					+ " FOREIGN KEY (contactId)"
@@ -133,8 +133,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 
 	private static final String CREATE_MESSAGES =
 			"CREATE TABLE messages"
-					+ " (messageId HASH NOT NULL,"
+					+ " (messageId _HASH NOT NULL,"
-					+ " groupId HASH NOT NULL,"
+					+ " groupId _HASH NOT NULL,"
 					+ " timestamp BIGINT NOT NULL,"
 					+ " state INT NOT NULL,"
 					+ " shared BOOLEAN NOT NULL,"
@@ -147,19 +147,19 @@ abstract class JdbcDatabase implements Database<Connection> {
 
 	private static final String CREATE_MESSAGE_METADATA =
 			"CREATE TABLE messageMetadata"
-					+ " (messageId HASH NOT NULL,"
+					+ " (messageId _HASH NOT NULL,"
-					+ " key VARCHAR NOT NULL,"
+					+ " metaKey _STRING NOT NULL,"
-					+ " value BINARY NOT NULL,"
+					+ " value _BINARY NOT NULL,"
-					+ " PRIMARY KEY (messageId, key),"
+					+ " PRIMARY KEY (messageId, metaKey),"
 					+ " FOREIGN KEY (messageId)"
 					+ " REFERENCES messages (messageId)"
 					+ " ON DELETE CASCADE)";
 
 	private static final String CREATE_MESSAGE_DEPENDENCIES =
 			"CREATE TABLE messageDependencies"
-					+ " (groupId HASH NOT NULL,"
+					+ " (groupId _HASH NOT NULL,"
-					+ " messageId HASH NOT NULL,"
+					+ " messageId _HASH NOT NULL,"
-					+ " dependencyId HASH NOT NULL," // Not a foreign key
+					+ " dependencyId _HASH NOT NULL," // Not a foreign key
 					+ " FOREIGN KEY (groupId)"
 					+ " REFERENCES groups (groupId)"
 					+ " ON DELETE CASCADE,"
@@ -169,7 +169,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 
 	private static final String CREATE_OFFERS =
 			"CREATE TABLE offers"
-					+ " (messageId HASH NOT NULL," // Not a foreign key
+					+ " (messageId _HASH NOT NULL," // Not a foreign key
 					+ " contactId INT NOT NULL,"
 					+ " PRIMARY KEY (messageId, contactId),"
 					+ " FOREIGN KEY (contactId)"
@@ -178,7 +178,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 
 	private static final String CREATE_STATUSES =
 			"CREATE TABLE statuses"
-					+ " (messageId HASH NOT NULL,"
+					+ " (messageId _HASH NOT NULL,"
 					+ " contactId INT NOT NULL,"
 					+ " ack BOOLEAN NOT NULL,"
 					+ " seen BOOLEAN NOT NULL,"
@@ -195,20 +195,20 @@ abstract class JdbcDatabase implements Database<Connection> {
 
 	private static final String CREATE_TRANSPORTS =
 			"CREATE TABLE transports"
-					+ " (transportId VARCHAR NOT NULL,"
+					+ " (transportId _STRING NOT NULL,"
 					+ " maxLatency INT NOT NULL,"
 					+ " PRIMARY KEY (transportId))";
 
 	private static final String CREATE_INCOMING_KEYS =
 			"CREATE TABLE incomingKeys"
 					+ " (contactId INT NOT NULL,"
-					+ " transportId VARCHAR NOT NULL,"
+					+ " transportId _STRING NOT NULL,"
-					+ " period BIGINT NOT NULL,"
+					+ " rotationPeriod BIGINT NOT NULL,"
-					+ " tagKey SECRET NOT NULL,"
+					+ " tagKey _SECRET NOT NULL,"
-					+ " headerKey SECRET NOT NULL,"
+					+ " headerKey _SECRET NOT NULL,"
 					+ " base BIGINT NOT NULL,"
-					+ " bitmap BINARY NOT NULL,"
+					+ " bitmap _BINARY NOT NULL,"
-					+ " PRIMARY KEY (contactId, transportId, period),"
+					+ " PRIMARY KEY (contactId, transportId, rotationPeriod),"
 					+ " FOREIGN KEY (contactId)"
 					+ " REFERENCES contacts (contactId)"
 					+ " ON DELETE CASCADE,"
@@ -219,10 +219,10 @@ abstract class JdbcDatabase implements Database<Connection> {
 	private static final String CREATE_OUTGOING_KEYS =
 			"CREATE TABLE outgoingKeys"
 					+ " (contactId INT NOT NULL,"
-					+ " transportId VARCHAR NOT NULL,"
+					+ " transportId _STRING NOT NULL,"
-					+ " period BIGINT NOT NULL,"
+					+ " rotationPeriod BIGINT NOT NULL,"
-					+ " tagKey SECRET NOT NULL,"
+					+ " tagKey _SECRET NOT NULL,"
-					+ " headerKey SECRET NOT NULL,"
+					+ " headerKey _SECRET NOT NULL,"
 					+ " stream BIGINT NOT NULL,"
 					+ " PRIMARY KEY (contactId, transportId),"
 					+ " FOREIGN KEY (contactId)"
@@ -232,15 +232,40 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " REFERENCES transports (transportId)"
 					+ " ON DELETE CASCADE)";
 
+	private static final String INDEX_CONTACTS_BY_AUTHOR_ID =
+			"CREATE INDEX IF NOT EXISTS contactsByAuthorId"
+					+ " ON contacts (authorId)";
+
+	private static final String INDEX_MESSAGES_BY_GROUP_ID =
+			"CREATE INDEX IF NOT EXISTS messagesByGroupId"
+					+ " ON messages (groupId)";
+
+	private static final String INDEX_OFFERS_BY_CONTACT_ID =
+			"CREATE INDEX IF NOT EXISTS offersByContactId"
+					+ " ON offers (contactId)";
+
+	private static final String INDEX_GROUPS_BY_CLIENT_ID =
+			"CREATE INDEX IF NOT EXISTS groupsByClientId"
+					+ " ON groups (clientId)";
+
+	private static final String INDEX_MESSAGE_METADATA_BY_MESSAGE_ID =
+			"CREATE INDEX IF NOT EXISTS messageMetadataByMessageId"
+					+ " ON messageMetadata (messageId)";
+
+	private static final String INDEX_GROUP_METADATA_BY_GROUP_ID =
+			"CREATE INDEX IF NOT EXISTS groupMetadataByGroupId"
+					+ " ON groupMetadata (groupId)";
+
 	private static final Logger LOG =
 			Logger.getLogger(JdbcDatabase.class.getName());
 
 	// Different database libraries use different names for certain types
-	private final String hashType, binaryType, counterType, secretType;
+	private final String hashType, secretType, binaryType;
+	private final String counterType, stringType;
 	private final Clock clock;
 
-	private final LinkedList<Connection> connections =
+	// Locking: connectionsLock
-			new LinkedList<Connection>(); // Locking: connectionsLock
+	private final LinkedList<Connection> connections = new LinkedList<>();
 
 	private int openConnections = 0; // Locking: connectionsLock
 	private boolean closed = false; // Locking: connectionsLock
@@ -251,12 +276,13 @@ abstract class JdbcDatabase implements Database<Connection> {
 	private final Lock connectionsLock = new ReentrantLock();
 	private final Condition connectionsChanged = connectionsLock.newCondition();
 
-	JdbcDatabase(String hashType, String binaryType, String counterType,
+	JdbcDatabase(String hashType, String secretType, String binaryType,
-			String secretType, Clock clock) {
+			String counterType, String stringType, Clock clock) {
 		this.hashType = hashType;
+		this.secretType = secretType;
 		this.binaryType = binaryType;
 		this.counterType = counterType;
-		this.secretType = secretType;
+		this.stringType = stringType;
 		this.clock = clock;
 	}
 
@@ -267,7 +293,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		} catch (ClassNotFoundException e) {
 			throw new DbException(e);
 		}
-		// Open the database and create the tables if necessary
+		// Open the database and create the tables and indexes if necessary
 		Connection txn = startTransaction();
 		try {
 			if (reopen) {
@@ -276,6 +302,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 				createTables(txn);
 				storeSchemaVersion(txn);
 			}
+			createIndexes(txn);
 			commitTransaction(txn);
 		} catch (DbException e) {
 			abortTransaction(txn);
@@ -340,17 +367,35 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	private void createIndexes(Connection txn) throws DbException {
+		Statement s = null;
+		try {
+			s = txn.createStatement();
+			s.executeUpdate(INDEX_CONTACTS_BY_AUTHOR_ID);
+			s.executeUpdate(INDEX_MESSAGES_BY_GROUP_ID);
+			s.executeUpdate(INDEX_OFFERS_BY_CONTACT_ID);
+			s.executeUpdate(INDEX_GROUPS_BY_CLIENT_ID);
+			s.executeUpdate(INDEX_MESSAGE_METADATA_BY_MESSAGE_ID);
+			s.executeUpdate(INDEX_GROUP_METADATA_BY_GROUP_ID);
+			s.close();
+		} catch (SQLException e) {
+			tryToClose(s);
+			throw new DbException(e);
+		}
+	}
+
 	private String insertTypeNames(String s) {
-		s = s.replaceAll("HASH", hashType);
+		s = s.replaceAll("_HASH", hashType);
-		s = s.replaceAll("BINARY", binaryType);
+		s = s.replaceAll("_SECRET", secretType);
-		s = s.replaceAll("COUNTER", counterType);
+		s = s.replaceAll("_BINARY", binaryType);
-		s = s.replaceAll("SECRET", secretType);
+		s = s.replaceAll("_COUNTER", counterType);
+		s = s.replaceAll("_STRING", stringType);
 		return s;
 	}
 
 	@Override
 	public Connection startTransaction() throws DbException {
-		Connection txn = null;
+		Connection txn;
 		connectionsLock.lock();
 		try {
 			if (closed) throw new DbClosedException();
@@ -458,7 +503,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		try {
 			// Create a contact row
 			String sql = "INSERT INTO contacts"
-					+ " (authorId, name, publicKey, localAuthorId, verified, active)"
+					+ " (authorId, name, publicKey, localAuthorId,"
+					+ " verified, active)"
 					+ " VALUES (?, ?, ?, ?, ?, ?)";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, remote.getId().getBytes());
@@ -677,7 +723,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		try {
 			// Store the incoming keys
 			String sql = "INSERT INTO incomingKeys (contactId, transportId,"
-					+ " period, tagKey, headerKey, base, bitmap)"
+					+ " rotationPeriod, tagKey, headerKey, base, bitmap)"
 					+ " VALUES (?, ?, ?, ?, ?, ?, ?)";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, c.getInt());
@@ -712,8 +758,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 				if (rows != 1) throw new DbStateException();
 			ps.close();
 			// Store the outgoing keys
-			sql = "INSERT INTO outgoingKeys (contactId, transportId, period,"
+			sql = "INSERT INTO outgoingKeys (contactId, transportId,"
-					+ " tagKey, headerKey, stream)"
+					+ " rotationPeriod, tagKey, headerKey, stream)"
 					+ " VALUES (?, ?, ?, ?, ?, ?)";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, c.getInt());
@@ -993,7 +1039,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " FROM contacts";
 			ps = txn.prepareStatement(sql);
 			rs = ps.executeQuery();
-			List<Contact> contacts = new ArrayList<Contact>();
+			List<Contact> contacts = new ArrayList<>();
 			while (rs.next()) {
 				ContactId contactId = new ContactId(rs.getInt(1));
 				AuthorId authorId = new AuthorId(rs.getBytes(2));
@@ -1027,7 +1073,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, local.getBytes());
 			rs = ps.executeQuery();
-			List<ContactId> ids = new ArrayList<ContactId>();
+			List<ContactId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new ContactId(rs.getInt(1)));
 			rs.close();
 			ps.close();
@@ -1052,7 +1098,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, remote.getBytes());
 			rs = ps.executeQuery();
-			List<Contact> contacts = new ArrayList<Contact>();
+			List<Contact> contacts = new ArrayList<>();
 			while (rs.next()) {
 				ContactId c = new ContactId(rs.getInt(1));
 				String name = rs.getString(2);
@@ -1108,7 +1154,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, c.getString());
 			rs = ps.executeQuery();
-			List<Group> groups = new ArrayList<Group>();
+			List<Group> groups = new ArrayList<>();
 			while (rs.next()) {
 				GroupId id = new GroupId(rs.getBytes(1));
 				byte[] descriptor = rs.getBytes(2);
@@ -1161,7 +1207,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, g.getBytes());
 			rs = ps.executeQuery();
-			List<ContactId> visible = new ArrayList<ContactId>();
+			List<ContactId> visible = new ArrayList<>();
 			while (rs.next()) visible.add(new ContactId(rs.getInt(1)));
 			rs.close();
 			ps.close();
@@ -1213,7 +1259,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " FROM localAuthors";
 			ps = txn.prepareStatement(sql);
 			rs = ps.executeQuery();
-			List<LocalAuthor> authors = new ArrayList<LocalAuthor>();
+			List<LocalAuthor> authors = new ArrayList<>();
 			while (rs.next()) {
 				AuthorId authorId = new AuthorId(rs.getBytes(1));
 				String name = rs.getString(2);
@@ -1243,7 +1289,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, g.getBytes());
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1266,7 +1312,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(1, state.getValue());
 			ps.setBytes(2, g.getBytes());
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1293,7 +1339,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " JOIN messageMetadata AS md"
 					+ " ON m.messageId = md.messageId"
 					+ " WHERE state = ? AND groupId = ?"
-					+ " AND key = ? AND value = ?";
+					+ " AND metaKey = ? AND value = ?";
 			for (Entry<String, byte[]> e : query.entrySet()) {
 				ps = txn.prepareStatement(sql);
 				ps.setInt(1, DELIVERED.getValue());
@@ -1301,7 +1347,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 				ps.setString(3, e.getKey());
 				ps.setBytes(4, e.getValue());
 				rs = ps.executeQuery();
-				Set<MessageId> ids = new HashSet<MessageId>();
+				Set<MessageId> ids = new HashSet<>();
 				while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 				rs.close();
 				ps.close();
@@ -1325,7 +1371,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT m.messageId, key, value"
+			String sql = "SELECT m.messageId, metaKey, value"
 					+ " FROM messages AS m"
 					+ " JOIN messageMetadata AS md"
 					+ " ON m.messageId = md.messageId"
@@ -1335,7 +1381,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(1, DELIVERED.getValue());
 			ps.setBytes(2, g.getBytes());
 			rs = ps.executeQuery();
-			Map<MessageId, Metadata> all = new HashMap<MessageId, Metadata>();
+			Map<MessageId, Metadata> all = new HashMap<>();
 			Metadata metadata = null;
 			MessageId lastMessageId = null;
 			while (rs.next()) {
@@ -1364,8 +1410,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		Collection<MessageId> matches = getMessageIds(txn, g, query);
 		if (matches.isEmpty()) return Collections.emptyMap();
 		// Retrieve the metadata for each match
-		Map<MessageId, Metadata> all = new HashMap<MessageId, Metadata>(
+		Map<MessageId, Metadata> all = new HashMap<>(matches.size());
-				matches.size());
 		for (MessageId m : matches) all.put(m, getMessageMetadata(txn, m));
 		return all;
 	}
@@ -1376,7 +1421,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT key, value FROM groupMetadata"
+			String sql = "SELECT metaKey, value FROM groupMetadata"
 					+ " WHERE groupId = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, g.getBytes());
@@ -1399,7 +1444,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT key, value FROM messageMetadata AS md"
+			String sql = "SELECT metaKey, value FROM messageMetadata AS md"
 					+ " JOIN messages AS m"
 					+ " ON m.messageId = md.messageId"
 					+ " WHERE m.state = ? AND md.messageId = ?";
@@ -1425,7 +1470,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT key, value FROM messageMetadata AS md"
+			String sql = "SELECT metaKey, value FROM messageMetadata AS md"
 					+ " JOIN messages AS m"
 					+ " ON m.messageId = md.messageId"
 					+ " WHERE (m.state = ? OR m.state = ?)"
@@ -1463,7 +1508,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setBytes(1, g.getBytes());
 			ps.setInt(2, c.getInt());
 			rs = ps.executeQuery();
-			List<MessageStatus> statuses = new ArrayList<MessageStatus>();
+			List<MessageStatus> statuses = new ArrayList<>();
 			while (rs.next()) {
 				MessageId messageId = new MessageId(rs.getBytes(1));
 				boolean sent = rs.getBoolean(2);
@@ -1522,7 +1567,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			rs = ps.executeQuery();
-			Map<MessageId, State> dependencies = new HashMap<MessageId, State>();
+			Map<MessageId, State> dependencies = new HashMap<>();
 			while (rs.next()) {
 				MessageId dependency = new MessageId(rs.getBytes(1));
 				State state = State.fromValue(rs.getInt(2));
@@ -1560,7 +1605,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			rs = ps.executeQuery();
-			Map<MessageId, State> dependents = new HashMap<MessageId, State>();
+			Map<MessageId, State> dependents = new HashMap<>();
 			while (rs.next()) {
 				MessageId dependent = new MessageId(rs.getBytes(1));
 				State state = State.fromValue(rs.getInt(2));
@@ -1612,7 +1657,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(1, c.getInt());
 			ps.setInt(2, maxMessages);
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1648,7 +1693,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setLong(3, now);
 			ps.setInt(4, maxMessages);
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1673,7 +1718,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(1, c.getInt());
 			ps.setInt(2, maxMessages);
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1708,7 +1753,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(2, DELIVERED.getValue());
 			ps.setLong(3, now);
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			int total = 0;
 			while (rs.next()) {
 				int length = rs.getInt(1);
@@ -1750,7 +1795,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(1, state.getValue());
 			ps.setString(2, c.getString());
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1780,7 +1825,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, c.getString());
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1839,7 +1884,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(2, DELIVERED.getValue());
 			ps.setLong(3, now);
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			int total = 0;
 			while (rs.next()) {
 				int length = rs.getInt(1);
@@ -1863,7 +1908,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT key, value FROM settings WHERE namespace = ?";
+			String sql = "SELECT settingKey, value FROM settings"
+					+ " WHERE namespace = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, namespace);
 			rs = ps.executeQuery();
@@ -1886,14 +1932,15 @@ abstract class JdbcDatabase implements Database<Connection> {
 		ResultSet rs = null;
 		try {
 			// Retrieve the incoming keys
-			String sql = "SELECT period, tagKey, headerKey, base, bitmap"
+			String sql = "SELECT rotationPeriod, tagKey, headerKey,"
+					+ " base, bitmap"
 					+ " FROM incomingKeys"
 					+ " WHERE transportId = ?"
-					+ " ORDER BY contactId, period";
+					+ " ORDER BY contactId, rotationPeriod";
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, t.getString());
 			rs = ps.executeQuery();
-			List<IncomingKeys> inKeys = new ArrayList<IncomingKeys>();
+			List<IncomingKeys> inKeys = new ArrayList<>();
 			while (rs.next()) {
 				long rotationPeriod = rs.getLong(1);
 				SecretKey tagKey = new SecretKey(rs.getBytes(2));
@@ -1906,15 +1953,14 @@ abstract class JdbcDatabase implements Database<Connection> {
 			rs.close();
 			ps.close();
 			// Retrieve the outgoing keys in the same order
-			sql = "SELECT contactId, period, tagKey, headerKey, stream"
+			sql = "SELECT contactId, rotationPeriod, tagKey, headerKey, stream"
 					+ " FROM outgoingKeys"
 					+ " WHERE transportId = ?"
-					+ " ORDER BY contactId, period";
+					+ " ORDER BY contactId, rotationPeriod";
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, t.getString());
 			rs = ps.executeQuery();
-			Map<ContactId, TransportKeys> keys =
+			Map<ContactId, TransportKeys> keys = new HashMap<>();
-					new HashMap<ContactId, TransportKeys>();
 			for (int i = 0; rs.next(); i++) {
 				// There should be three times as many incoming keys
 				if (inKeys.size() < (i + 1) * 3) throw new DbStateException();
@@ -1947,7 +1993,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		try {
 			String sql = "UPDATE outgoingKeys SET stream = stream + 1"
-					+ " WHERE contactId = ? AND transportId = ? AND period = ?";
+					+ " WHERE contactId = ? AND transportId = ?"
+					+ " AND rotationPeriod = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, c.getInt());
 			ps.setString(2, t.getString());
@@ -2032,8 +2079,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		try {
 			// Determine which keys are being removed
-			List<String> removed = new ArrayList<String>();
+			List<String> removed = new ArrayList<>();
-			Map<String, byte[]> retained = new HashMap<String, byte[]>();
+			Map<String, byte[]> retained = new HashMap<>();
 			for (Entry<String, byte[]> e : meta.entrySet()) {
 				if (e.getValue() == REMOVE) removed.add(e.getKey());
 				else retained.put(e.getKey(), e.getValue());
@@ -2041,7 +2088,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			// Delete any keys that are being removed
 			if (!removed.isEmpty()) {
 				String sql = "DELETE FROM " + tableName
-						+ " WHERE " + columnName + " = ? AND key = ?";
+						+ " WHERE " + columnName + " = ? AND metaKey = ?";
 				ps = txn.prepareStatement(sql);
 				ps.setBytes(1, id);
 				for (String key : removed) {
@@ -2060,7 +2107,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			if (retained.isEmpty()) return;
 			// Update any keys that already exist
 			String sql = "UPDATE " + tableName + " SET value = ?"
-					+ " WHERE " + columnName + " = ? AND key = ?";
+					+ " WHERE " + columnName + " = ? AND metaKey = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(2, id);
 			for (Entry<String, byte[]> e : retained.entrySet()) {
@@ -2077,7 +2124,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			}
 			// Insert any keys that don't already exist
 			sql = "INSERT INTO " + tableName
-					+ " (" + columnName + ", key, value)"
+					+ " (" + columnName + ", metaKey, value)"
 					+ " VALUES (?, ?, ?)";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, id);
@@ -2109,7 +2156,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		try {
 			// Update any settings that already exist
 			String sql = "UPDATE settings SET value = ?"
-					+ " WHERE namespace = ? AND key = ?";
+					+ " WHERE namespace = ? AND settingKey = ?";
 			ps = txn.prepareStatement(sql);
 			for (Entry<String, String> e : s.entrySet()) {
 				ps.setString(1, e.getValue());
@@ -2124,7 +2171,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 				if (rows > 1) throw new DbStateException();
 			}
 			// Insert any settings that don't already exist
-			sql = "INSERT INTO settings (namespace, key, value)"
+			sql = "INSERT INTO settings (namespace, settingKey, value)"
 					+ " VALUES (?, ?, ?)";
 			ps = txn.prepareStatement(sql);
 			int updateIndex = 0, inserted = 0;
@@ -2488,7 +2535,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		try {
 			String sql = "UPDATE incomingKeys SET base = ?, bitmap = ?"
-					+ " WHERE contactId = ? AND transportId = ? AND period = ?";
+					+ " WHERE contactId = ? AND transportId = ?"
+					+ " AND rotationPeriod = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setLong(1, base);
 			ps.setBytes(2, bitmap);

bramble-core/src/main/java/org/briarproject/bramble/event/EventBusImpl.java

@@ -15,7 +15,7 @@ import javax.annotation.concurrent.ThreadSafe;
 class EventBusImpl implements EventBus {
 
 	private final Collection<EventListener> listeners =
-			new CopyOnWriteArrayList<EventListener>();
+			new CopyOnWriteArrayList<>();
 
 	@Override
 	public void addListener(EventListener l) {

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/KeyAgreementConnector.java

@@ -1,6 +1,6 @@
 package org.briarproject.bramble.keyagreement;
 
-import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.KeyAgreementCrypto;
 import org.briarproject.bramble.api.crypto.KeyPair;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementConnection;
@@ -46,37 +46,34 @@ class KeyAgreementConnector {
 
 	private final Callbacks callbacks;
 	private final Clock clock;
-	private final CryptoComponent crypto;
+	private final KeyAgreementCrypto keyAgreementCrypto;
 	private final PluginManager pluginManager;
 	private final CompletionService<KeyAgreementConnection> connect;
 
-	private final List<KeyAgreementListener> listeners =
+	private final List<KeyAgreementListener> listeners = new ArrayList<>();
-			new ArrayList<KeyAgreementListener>();
 	private final List<Future<KeyAgreementConnection>> pending =
-			new ArrayList<Future<KeyAgreementConnection>>();
+			new ArrayList<>();
 
 	private volatile boolean connecting = false;
 	private volatile boolean alice = false;
 
 	KeyAgreementConnector(Callbacks callbacks, Clock clock,
-			CryptoComponent crypto, PluginManager pluginManager,
+			KeyAgreementCrypto keyAgreementCrypto, PluginManager pluginManager,
 			Executor ioExecutor) {
 		this.callbacks = callbacks;
 		this.clock = clock;
-		this.crypto = crypto;
+		this.keyAgreementCrypto = keyAgreementCrypto;
 		this.pluginManager = pluginManager;
-		connect = new ExecutorCompletionService<KeyAgreementConnection>(
+		connect = new ExecutorCompletionService<>(ioExecutor);
-				ioExecutor);
 	}
 
 	public Payload listen(KeyPair localKeyPair) {
 		LOG.info("Starting BQP listeners");
 		// Derive commitment
-		byte[] commitment = crypto.deriveKeyCommitment(
+		byte[] commitment = keyAgreementCrypto.deriveKeyCommitment(
-				localKeyPair.getPublic().getEncoded());
+				localKeyPair.getPublic());
 		// Start all listeners and collect their descriptors
-		List<TransportDescriptor> descriptors =
+		List<TransportDescriptor> descriptors = new ArrayList<>();
-				new ArrayList<TransportDescriptor>();
 		for (DuplexPlugin plugin : pluginManager.getKeyAgreementPlugins()) {
 			KeyAgreementListener l =
 					plugin.createKeyAgreementListener(commitment);
@@ -132,10 +129,7 @@ class KeyAgreementConnector {
 			LOG.info("Interrupted while waiting for connection");
 			Thread.currentThread().interrupt();
 			return null;
-		} catch (ExecutionException e) {
+		} catch (ExecutionException | IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			return null;
-		} catch (IOException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			return null;
 		} finally {

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/KeyAgreementModule.java

@@ -1,19 +1,10 @@
 package org.briarproject.bramble.keyagreement;
 
-import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.data.BdfReaderFactory;
 import org.briarproject.bramble.api.data.BdfWriterFactory;
-import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.keyagreement.KeyAgreementTask;
-import org.briarproject.bramble.api.keyagreement.KeyAgreementTaskFactory;
 import org.briarproject.bramble.api.keyagreement.PayloadEncoder;
 import org.briarproject.bramble.api.keyagreement.PayloadParser;
-import org.briarproject.bramble.api.lifecycle.IoExecutor;
-import org.briarproject.bramble.api.plugin.PluginManager;
-import org.briarproject.bramble.api.system.Clock;
-
-import java.util.concurrent.Executor;
-
-import javax.inject.Singleton;
 
 import dagger.Module;
 import dagger.Provides;
@@ -22,13 +13,9 @@ import dagger.Provides;
 public class KeyAgreementModule {
 
 	@Provides
-	@Singleton
+	KeyAgreementTask provideKeyAgreementTask(
-	KeyAgreementTaskFactory provideKeyAgreementTaskFactory(Clock clock,
+			KeyAgreementTaskImpl keyAgreementTask) {
-			CryptoComponent crypto, EventBus eventBus,
+		return keyAgreementTask;
-			@IoExecutor Executor ioExecutor, PayloadEncoder payloadEncoder,
-			PluginManager pluginManager) {
-		return new KeyAgreementTaskFactoryImpl(clock, crypto, eventBus,
-				ioExecutor, payloadEncoder, pluginManager);
 	}
 
 	@Provides

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/KeyAgreementProtocol.java

@@ -1,7 +1,10 @@
 package org.briarproject.bramble.keyagreement;
 
 import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.KeyAgreementCrypto;
 import org.briarproject.bramble.api.crypto.KeyPair;
+import org.briarproject.bramble.api.crypto.KeyParser;
+import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.keyagreement.Payload;
 import org.briarproject.bramble.api.keyagreement.PayloadEncoder;
@@ -11,6 +14,10 @@ import java.io.IOException;
 import java.security.GeneralSecurityException;
 import java.util.Arrays;
 
+import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.MASTER_SECRET_LABEL;
+import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.PROTOCOL_VERSION;
+import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.SHARED_SECRET_LABEL;
+
 /**
  * Implementation of the BQP protocol.
  * <p/>
@@ -57,6 +64,7 @@ class KeyAgreementProtocol {
 
 	private final Callbacks callbacks;
 	private final CryptoComponent crypto;
+	private final KeyAgreementCrypto keyAgreementCrypto;
 	private final PayloadEncoder payloadEncoder;
 	private final KeyAgreementTransport transport;
 	private final Payload theirPayload, ourPayload;
@@ -64,11 +72,13 @@ class KeyAgreementProtocol {
 	private final boolean alice;
 
 	KeyAgreementProtocol(Callbacks callbacks, CryptoComponent crypto,
+			KeyAgreementCrypto keyAgreementCrypto,
 			PayloadEncoder payloadEncoder, KeyAgreementTransport transport,
 			Payload theirPayload, Payload ourPayload, KeyPair ourKeyPair,
 			boolean alice) {
 		this.callbacks = callbacks;
 		this.crypto = crypto;
+		this.keyAgreementCrypto = keyAgreementCrypto;
 		this.payloadEncoder = payloadEncoder;
 		this.transport = transport;
 		this.theirPayload = theirPayload;
@@ -86,7 +96,7 @@ class KeyAgreementProtocol {
 	 */
 	SecretKey perform() throws AbortException, IOException {
 		try {
-			byte[] theirPublicKey;
+			PublicKey theirPublicKey;
 			if (alice) {
 				sendKey();
 				// Alice waits here until Bob obtains her payload.
@@ -104,7 +114,7 @@ class KeyAgreementProtocol {
 				receiveConfirm(s, theirPublicKey);
 				sendConfirm(s, theirPublicKey);
 			}
-			return crypto.deriveMasterSecret(s);
+			return crypto.deriveKey(MASTER_SECRET_LABEL, s);
 		} catch (AbortException e) {
 			sendAbort(e.getCause() != null);
 			throw e;
@@ -115,27 +125,41 @@ class KeyAgreementProtocol {
 		transport.sendKey(ourKeyPair.getPublic().getEncoded());
 	}
 
-	private byte[] receiveKey() throws AbortException {
+	private PublicKey receiveKey() throws AbortException {
-		byte[] publicKey = transport.receiveKey();
+		byte[] publicKeyBytes = transport.receiveKey();
 		callbacks.initialRecordReceived();
-		byte[] expected = crypto.deriveKeyCommitment(publicKey);
+		KeyParser keyParser = crypto.getAgreementKeyParser();
-		if (!Arrays.equals(expected, theirPayload.getCommitment()))
+		try {
+			PublicKey publicKey = keyParser.parsePublicKey(publicKeyBytes);
+			byte[] expected = keyAgreementCrypto.deriveKeyCommitment(publicKey);
+			if (!Arrays.equals(expected, theirPayload.getCommitment()))
+				throw new AbortException();
+			return publicKey;
+		} catch (GeneralSecurityException e) {
 			throw new AbortException();
-		return publicKey;
+		}
 	}
 
-	private SecretKey deriveSharedSecret(byte[] theirPublicKey)
+	private SecretKey deriveSharedSecret(PublicKey theirPublicKey)
 			throws AbortException {
 		try {
-			return crypto.deriveSharedSecret(theirPublicKey, ourKeyPair, alice);
+			byte[] ourPublicKeyBytes = ourKeyPair.getPublic().getEncoded();
+			byte[] theirPublicKeyBytes = theirPublicKey.getEncoded();
+			byte[][] inputs = {
+					new byte[] {PROTOCOL_VERSION},
+					alice ? ourPublicKeyBytes : theirPublicKeyBytes,
+					alice ? theirPublicKeyBytes : ourPublicKeyBytes
+			};
+			return crypto.deriveSharedSecret(SHARED_SECRET_LABEL,
+					theirPublicKey, ourKeyPair, inputs);
 		} catch (GeneralSecurityException e) {
 			throw new AbortException(e);
 		}
 	}
 
-	private void sendConfirm(SecretKey s, byte[] theirPublicKey)
+	private void sendConfirm(SecretKey s, PublicKey theirPublicKey)
 			throws IOException {
-		byte[] confirm = crypto.deriveConfirmationRecord(s,
+		byte[] confirm = keyAgreementCrypto.deriveConfirmationRecord(s,
 				payloadEncoder.encode(theirPayload),
 				payloadEncoder.encode(ourPayload),
 				theirPublicKey, ourKeyPair,
@@ -143,10 +167,10 @@ class KeyAgreementProtocol {
 		transport.sendConfirm(confirm);
 	}
 
-	private void receiveConfirm(SecretKey s, byte[] theirPublicKey)
+	private void receiveConfirm(SecretKey s, PublicKey theirPublicKey)
 			throws AbortException {
 		byte[] confirm = transport.receiveConfirm();
-		byte[] expected = crypto.deriveConfirmationRecord(s,
+		byte[] expected = keyAgreementCrypto.deriveConfirmationRecord(s,
 				payloadEncoder.encode(theirPayload),
 				payloadEncoder.encode(ourPayload),
 				theirPublicKey, ourKeyPair,

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/KeyAgreementTaskFactoryImpl.java

@@ -1,46 +0,0 @@
-package org.briarproject.bramble.keyagreement;
-
-import org.briarproject.bramble.api.crypto.CryptoComponent;
-import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.keyagreement.KeyAgreementTask;
-import org.briarproject.bramble.api.keyagreement.KeyAgreementTaskFactory;
-import org.briarproject.bramble.api.keyagreement.PayloadEncoder;
-import org.briarproject.bramble.api.lifecycle.IoExecutor;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.PluginManager;
-import org.briarproject.bramble.api.system.Clock;
-
-import java.util.concurrent.Executor;
-
-import javax.annotation.concurrent.Immutable;
-import javax.inject.Inject;
-
-@Immutable
-@NotNullByDefault
-class KeyAgreementTaskFactoryImpl implements KeyAgreementTaskFactory {
-
-	private final Clock clock;
-	private final CryptoComponent crypto;
-	private final EventBus eventBus;
-	private final Executor ioExecutor;
-	private final PayloadEncoder payloadEncoder;
-	private final PluginManager pluginManager;
-
-	@Inject
-	KeyAgreementTaskFactoryImpl(Clock clock, CryptoComponent crypto,
-			EventBus eventBus, @IoExecutor Executor ioExecutor,
-			PayloadEncoder payloadEncoder, PluginManager pluginManager) {
-		this.clock = clock;
-		this.crypto = crypto;
-		this.eventBus = eventBus;
-		this.ioExecutor = ioExecutor;
-		this.payloadEncoder = payloadEncoder;
-		this.pluginManager = pluginManager;
-	}
-
-	@Override
-	public KeyAgreementTask createTask() {
-		return new KeyAgreementTaskImpl(clock, crypto, eventBus, payloadEncoder,
-				pluginManager, ioExecutor);
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/KeyAgreementTaskImpl.java

@@ -1,6 +1,7 @@
 package org.briarproject.bramble.keyagreement;
 
 import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.KeyAgreementCrypto;
 import org.briarproject.bramble.api.crypto.KeyPair;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.event.EventBus;
@@ -14,6 +15,7 @@ import org.briarproject.bramble.api.keyagreement.event.KeyAgreementFinishedEvent
 import org.briarproject.bramble.api.keyagreement.event.KeyAgreementListeningEvent;
 import org.briarproject.bramble.api.keyagreement.event.KeyAgreementStartedEvent;
 import org.briarproject.bramble.api.keyagreement.event.KeyAgreementWaitingEvent;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.PluginManager;
@@ -23,6 +25,8 @@ import java.io.IOException;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
+import javax.inject.Inject;
+
 import static java.util.logging.Level.WARNING;
 
 @MethodsNotNullByDefault
@@ -35,6 +39,7 @@ class KeyAgreementTaskImpl extends Thread implements
 			Logger.getLogger(KeyAgreementTaskImpl.class.getName());
 
 	private final CryptoComponent crypto;
+	private final KeyAgreementCrypto keyAgreementCrypto;
 	private final EventBus eventBus;
 	private final PayloadEncoder payloadEncoder;
 	private final KeyPair localKeyPair;
@@ -43,14 +48,17 @@ class KeyAgreementTaskImpl extends Thread implements
 	private Payload localPayload;
 	private Payload remotePayload;
 
+	@Inject
 	KeyAgreementTaskImpl(Clock clock, CryptoComponent crypto,
-			EventBus eventBus, PayloadEncoder payloadEncoder,
+			KeyAgreementCrypto keyAgreementCrypto, EventBus eventBus,
-			PluginManager pluginManager, Executor ioExecutor) {
+			PayloadEncoder payloadEncoder, PluginManager pluginManager,
+			@IoExecutor Executor ioExecutor) {
 		this.crypto = crypto;
+		this.keyAgreementCrypto = keyAgreementCrypto;
 		this.eventBus = eventBus;
 		this.payloadEncoder = payloadEncoder;
 		localKeyPair = crypto.generateAgreementKeyPair();
-		connector = new KeyAgreementConnector(this, clock, crypto,
+		connector = new KeyAgreementConnector(this, clock, keyAgreementCrypto,
 				pluginManager, ioExecutor);
 	}
 
@@ -100,8 +108,8 @@ class KeyAgreementTaskImpl extends Thread implements
 		// Run BQP protocol over the connection
 		LOG.info("Starting BQP protocol");
 		KeyAgreementProtocol protocol = new KeyAgreementProtocol(this, crypto,
-				payloadEncoder, transport, remotePayload, localPayload,
+				keyAgreementCrypto, payloadEncoder, transport, remotePayload,
-				localKeyPair, alice);
+				localPayload, localKeyPair, alice);
 		try {
 			SecretKey master = protocol.perform();
 			KeyAgreementResult result =

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/PayloadParserImpl.java

@@ -51,8 +51,7 @@ class PayloadParserImpl implements PayloadParser {
 		byte[] commitment = payload.getRaw(1);
 		if (commitment.length != COMMIT_LENGTH) throw new FormatException();
 		// Remaining elements: transport descriptors
-		List<TransportDescriptor> recognised =
+		List<TransportDescriptor> recognised = new ArrayList<>();
-				new ArrayList<TransportDescriptor>();
 		for (int i = 2; i < payload.size(); i++) {
 			BdfList descriptor = payload.getList(i);
 			long transportId = descriptor.getLong(0);

bramble-core/src/main/java/org/briarproject/bramble/lifecycle/LifecycleManagerImpl.java

@@ -63,9 +63,9 @@ class LifecycleManagerImpl implements LifecycleManager {
 		this.crypto = crypto;
 		this.authorFactory = authorFactory;
 		this.identityManager = identityManager;
-		services = new CopyOnWriteArrayList<Service>();
+		services = new CopyOnWriteArrayList<>();
-		clients = new CopyOnWriteArrayList<Client>();
+		clients = new CopyOnWriteArrayList<>();
-		executors = new CopyOnWriteArrayList<ExecutorService>();
+		executors = new CopyOnWriteArrayList<>();
 	}
 
 	@Override
@@ -88,7 +88,7 @@ class LifecycleManagerImpl implements LifecycleManager {
 		executors.add(e);
 	}
 
-	private LocalAuthor createLocalAuthor(final String nickname) {
+	private LocalAuthor createLocalAuthor(String nickname) {
 		long now = System.currentTimeMillis();
 		KeyPair keyPair = crypto.generateSignatureKeyPair();
 		byte[] publicKey = keyPair.getPublic().getEncoded();
@@ -203,9 +203,7 @@ class LifecycleManagerImpl implements LifecycleManager {
 			if (LOG.isLoggable(INFO))
 				LOG.info("Closing database took " + duration + " ms");
 			shutdownLatch.countDown();
-		} catch (DbException e) {
+		} catch (DbException | ServiceException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		} catch (ServiceException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 		} finally {
 			startStopSemaphore.release();

bramble-core/src/main/java/org/briarproject/bramble/lifecycle/LifecycleModule.java

@@ -37,7 +37,7 @@ public class LifecycleModule {
 
 	public LifecycleModule() {
 		// The thread pool is unbounded, so use direct handoff
-		BlockingQueue<Runnable> queue = new SynchronousQueue<Runnable>();
+		BlockingQueue<Runnable> queue = new SynchronousQueue<>();
 		// Discard tasks that are submitted during shutdown
 		RejectedExecutionHandler policy =
 				new ThreadPoolExecutor.DiscardPolicy();

bramble-core/src/main/java/org/briarproject/bramble/lifecycle/ShutdownManagerImpl.java

@@ -21,7 +21,7 @@ class ShutdownManagerImpl implements ShutdownManager {
 	private int nextHandle = 0;
 
 	ShutdownManagerImpl() {
-		hooks = new HashMap<Integer, Thread>();
+		hooks = new HashMap<>();
 	}
 
 	@Override

bramble-core/src/main/java/org/briarproject/bramble/plugin/ConnectionManagerImpl.java

@@ -134,11 +134,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			try {
 				byte[] tag = readTag(reader);
 				ctx = keyManager.getStreamContext(transportId, tag);
-			} catch (IOException e) {
+			} catch (IOException | DbException e) {
-				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-				disposeReader(true, false);
-				return;
-			} catch (DbException e) {
 				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 				disposeReader(true, false);
 				return;
@@ -249,11 +245,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			try {
 				byte[] tag = readTag(reader);
 				ctx = keyManager.getStreamContext(transportId, tag);
-			} catch (IOException e) {
+			} catch (IOException | DbException e) {
-				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-				disposeReader(true, false);
-				return;
-			} catch (DbException e) {
 				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 				disposeReader(true, false);
 				return;
@@ -266,12 +258,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			contactId = ctx.getContactId();
 			connectionRegistry.registerConnection(contactId, transportId, true);
 			// Start the outgoing session on another thread
-			ioExecutor.execute(new Runnable() {
+			ioExecutor.execute(this::runOutgoingSession);
-				@Override
-				public void run() {
-					runOutgoingSession();
-				}
-			});
 			try {
 				// Create and run the incoming session
 				incomingSession = createIncomingSession(ctx, reader);
@@ -368,12 +355,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 				return;
 			}
 			// Start the incoming session on another thread
-			ioExecutor.execute(new Runnable() {
+			ioExecutor.execute(this::runIncomingSession);
-				@Override
-				public void run() {
-					runIncomingSession();
-				}
-			});
 			try {
 				// Create and run the outgoing session
 				outgoingSession = createDuplexOutgoingSession(ctx, writer);
@@ -391,11 +373,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			try {
 				byte[] tag = readTag(reader);
 				ctx = keyManager.getStreamContext(transportId, tag);
-			} catch (IOException e) {
+			} catch (IOException | DbException e) {
-				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-				disposeReader(true, false);
-				return;
-			} catch (DbException e) {
 				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 				disposeReader(true, false);
 				return;

bramble-core/src/main/java/org/briarproject/bramble/plugin/ConnectionRegistryImpl.java

@@ -42,8 +42,8 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 	@Inject
 	ConnectionRegistryImpl(EventBus eventBus) {
 		this.eventBus = eventBus;
-		connections = new HashMap<TransportId, Map<ContactId, Integer>>();
+		connections = new HashMap<>();
-		contactCounts = new HashMap<ContactId, Integer>();
+		contactCounts = new HashMap<>();
 	}
 
 	@Override
@@ -58,7 +58,7 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 		try {
 			Map<ContactId, Integer> m = connections.get(t);
 			if (m == null) {
-				m = new HashMap<ContactId, Integer>();
+				m = new HashMap<>();
 				connections.put(t, m);
 			}
 			Integer count = m.get(c);
@@ -124,7 +124,7 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 		try {
 			Map<ContactId, Integer> m = connections.get(t);
 			if (m == null) return Collections.emptyList();
-			List<ContactId> ids = new ArrayList<ContactId>(m.keySet());
+			List<ContactId> ids = new ArrayList<>(m.keySet());
 			if (LOG.isLoggable(INFO))
 				LOG.info(ids.size() + " contacts connected");
 			return ids;

bramble-core/src/main/java/org/briarproject/bramble/plugin/PluginManagerImpl.java

@@ -82,10 +82,10 @@ class PluginManagerImpl implements PluginManager, Service {
 		this.settingsManager = settingsManager;
 		this.transportPropertyManager = transportPropertyManager;
 		this.uiCallback = uiCallback;
-		plugins = new ConcurrentHashMap<TransportId, Plugin>();
+		plugins = new ConcurrentHashMap<>();
-		simplexPlugins = new CopyOnWriteArrayList<SimplexPlugin>();
+		simplexPlugins = new CopyOnWriteArrayList<>();
-		duplexPlugins = new CopyOnWriteArrayList<DuplexPlugin>();
+		duplexPlugins = new CopyOnWriteArrayList<>();
-		startLatches = new ConcurrentHashMap<TransportId, CountDownLatch>();
+		startLatches = new ConcurrentHashMap<>();
 	}
 
 	@Override
@@ -156,17 +156,17 @@ class PluginManagerImpl implements PluginManager, Service {
 
 	@Override
 	public Collection<SimplexPlugin> getSimplexPlugins() {
-		return new ArrayList<SimplexPlugin>(simplexPlugins);
+		return new ArrayList<>(simplexPlugins);
 	}
 
 	@Override
 	public Collection<DuplexPlugin> getDuplexPlugins() {
-		return new ArrayList<DuplexPlugin>(duplexPlugins);
+		return new ArrayList<>(duplexPlugins);
 	}
 
 	@Override
 	public Collection<DuplexPlugin> getKeyAgreementPlugins() {
-		List<DuplexPlugin> supported = new ArrayList<DuplexPlugin>();
+		List<DuplexPlugin> supported = new ArrayList<>();
 		for (DuplexPlugin d : duplexPlugins)
 			if (d.supportsKeyAgreement()) supported.add(d);
 		return supported;

bramble-core/src/main/java/org/briarproject/bramble/plugin/Poller.java

@@ -66,7 +66,7 @@ class Poller implements EventListener {
 		this.random = random;
 		this.clock = clock;
 		lock = new ReentrantLock();
-		tasks = new HashMap<TransportId, PollTask>();
+		tasks = new HashMap<>();
 	}
 
 	@Override
@@ -111,30 +111,24 @@ class Poller implements EventListener {
 			connectToContact(c, (DuplexPlugin) p);
 	}
 
-	private void connectToContact(final ContactId c, final SimplexPlugin p) {
+	private void connectToContact(ContactId c, SimplexPlugin p) {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(() -> {
-			@Override
+			TransportId t = p.getId();
-			public void run() {
+			if (!connectionRegistry.isConnected(c, t)) {
-				TransportId t = p.getId();
+				TransportConnectionWriter w = p.createWriter(c);
-				if (!connectionRegistry.isConnected(c, t)) {
+				if (w != null)
-					TransportConnectionWriter w = p.createWriter(c);
+					connectionManager.manageOutgoingConnection(c, t, w);
-					if (w != null)
-						connectionManager.manageOutgoingConnection(c, t, w);
-				}
 			}
 		});
 	}
 
-	private void connectToContact(final ContactId c, final DuplexPlugin p) {
+	private void connectToContact(ContactId c, DuplexPlugin p) {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(() -> {
-			@Override
+			TransportId t = p.getId();
-			public void run() {
+			if (!connectionRegistry.isConnected(c, t)) {
-				TransportId t = p.getId();
+				DuplexTransportConnection d = p.createConnection(c);
-				if (!connectionRegistry.isConnected(c, t)) {
+				if (d != null)
-					DuplexTransportConnection d = p.createConnection(c);
+					connectionManager.manageOutgoingConnection(c, t, d);
-					if (d != null)
-						connectionManager.manageOutgoingConnection(c, t, d);
-				}
 			}
 		});
 	}
@@ -159,14 +153,10 @@ class Poller implements EventListener {
 		try {
 			PollTask scheduled = tasks.get(t);
 			if (scheduled == null || due < scheduled.due) {
-				final PollTask task = new PollTask(p, due, randomiseNext);
+				PollTask task = new PollTask(p, due, randomiseNext);
 				tasks.put(t, task);
-				scheduler.schedule(new Runnable() {
+				scheduler.schedule(
-					@Override
+						() -> ioExecutor.execute(task), delay, MILLISECONDS);
-					public void run() {
-						ioExecutor.execute(task);
-					}
-				}, delay, MILLISECONDS);
 			}
 		} finally {
 			lock.unlock();
@@ -174,7 +164,7 @@ class Poller implements EventListener {
 	}
 
 	@IoExecutor
-	private void poll(final Plugin p) {
+	private void poll(Plugin p) {
 		TransportId t = p.getId();
 		if (LOG.isLoggable(INFO)) LOG.info("Polling plugin " + t);
 		p.poll(connectionRegistry.getConnectedContacts(t));

bramble-core/src/main/java/org/briarproject/bramble/plugin/file/FilePlugin.java

@@ -108,7 +108,7 @@ abstract class FilePlugin implements SimplexPlugin {
 		}
 	}
 
-	protected void createReaderFromFile(final File f) {
+	protected void createReaderFromFile(File f) {
 		if (!running) return;
 		ioExecutor.execute(new ReaderCreator(f));
 	}

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/LanTcpPlugin.java

@@ -63,7 +63,7 @@ class LanTcpPlugin extends TcpPlugin {
 		TransportProperties p = callback.getLocalProperties();
 		String oldIpPorts = p.get(PROP_IP_PORTS);
 		List<InetSocketAddress> olds = parseSocketAddresses(oldIpPorts);
-		List<InetSocketAddress> locals = new LinkedList<InetSocketAddress>();
+		List<InetSocketAddress> locals = new LinkedList<>();
 		for (InetAddress local : getLocalIpAddresses()) {
 			if (isAcceptableAddress(local)) {
 				// If this is the old address, try to use the same port
@@ -82,7 +82,7 @@ class LanTcpPlugin extends TcpPlugin {
 	private List<InetSocketAddress> parseSocketAddresses(String ipPorts) {
 		if (StringUtils.isNullOrEmpty(ipPorts)) return Collections.emptyList();
 		String[] split = ipPorts.split(SEPARATOR);
-		List<InetSocketAddress> addresses = new ArrayList<InetSocketAddress>();
+		List<InetSocketAddress> addresses = new ArrayList<>();
 		for (String ipPort : split) {
 			InetSocketAddress a = parseSocketAddress(ipPort);
 			if (a != null) addresses.add(a);
@@ -95,7 +95,7 @@ class LanTcpPlugin extends TcpPlugin {
 		String ipPort = getIpPortString(a);
 		// Get the list of recently used addresses
 		String setting = callback.getSettings().get(PREF_LAN_IP_PORTS);
-		List<String> recent = new ArrayList<String>();
+		List<String> recent = new ArrayList<>();
 		if (!StringUtils.isNullOrEmpty(setting))
 			Collections.addAll(recent, setting.split(SEPARATOR));
 		// Is the address already in the list?
@@ -111,7 +111,7 @@ class LanTcpPlugin extends TcpPlugin {
 				recent = recent.subList(0, MAX_ADDRESSES);
 			setting = StringUtils.join(recent, SEPARATOR);
 			// Update the list of addresses shared with contacts
-			List<String> shared = new ArrayList<String>(recent);
+			List<String> shared = new ArrayList<>(recent);
 			Collections.sort(shared);
 			String property = StringUtils.join(shared, SEPARATOR);
 			TransportProperties properties = new TransportProperties();
@@ -260,16 +260,12 @@ class LanTcpPlugin extends TcpPlugin {
 
 		@Override
 		public Callable<KeyAgreementConnection> listen() {
-			return new Callable<KeyAgreementConnection>() {
+			return () -> {
-				@Override
+				Socket s = ss.accept();
-				public KeyAgreementConnection call() throws IOException {
+				if (LOG.isLoggable(INFO))
-					Socket s = ss.accept();
+					LOG.info(ID.getString() + ": Incoming connection");
-					if (LOG.isLoggable(INFO))
+				return new KeyAgreementConnection(
-						LOG.info(ID.getString() + ": Incoming connection");
+						new TcpTransportConnection(LanTcpPlugin.this, s), ID);
-					return new KeyAgreementConnection(
-							new TcpTransportConnection(LanTcpPlugin.this, s),
-							ID);
-				}
 			};
 		}
 

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/PortMapperImpl.java

@@ -37,7 +37,7 @@ class PortMapperImpl implements PortMapper {
 	}
 
 	@Override
-	public MappingResult map(final int port) {
+	public MappingResult map(int port) {
 		if (!started.getAndSet(true)) start();
 		if (gateway == null) return null;
 		InetAddress internal = gateway.getLocalAddress();
@@ -50,12 +50,7 @@ class PortMapperImpl implements PortMapper {
 			succeeded = gateway.addPortMapping(port, port,
 					getHostAddress(internal), "TCP", "TCP");
 			if (succeeded) {
-				shutdownManager.addShutdownHook(new Runnable() {
+				shutdownManager.addShutdownHook(() -> deleteMapping(port));
-					@Override
-					public void run() {
-						deleteMapping(port);
-					}
-				});
 			}
 			String externalString = gateway.getExternalIPAddress();
 			if (LOG.isLoggable(INFO))
@@ -63,9 +58,7 @@ class PortMapperImpl implements PortMapper {
 						"External address " + scrubInetAddress(externalString));
 			if (externalString != null)
 				external = InetAddress.getByName(externalString);
-		} catch (IOException e) {
+		} catch (IOException | SAXException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		} catch (SAXException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 		}
 		return new MappingResult(internal, external, port, succeeded);
@@ -82,11 +75,7 @@ class PortMapperImpl implements PortMapper {
 		GatewayDiscover d = new GatewayDiscover();
 		try {
 			d.discover();
-		} catch (IOException e) {
+		} catch (IOException | SAXException | ParserConfigurationException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		} catch (SAXException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		} catch (ParserConfigurationException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 		}
 		gateway = d.getValidGateway();
@@ -97,9 +86,7 @@ class PortMapperImpl implements PortMapper {
 			gateway.deletePortMapping(port, "TCP");
 			if (LOG.isLoggable(INFO))
 				LOG.info("Deleted mapping for port " + port);
-		} catch (IOException e) {
+		} catch (IOException | SAXException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		} catch (SAXException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 		}
 	}

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/TcpPlugin.java

@@ -110,41 +110,37 @@ abstract class TcpPlugin implements DuplexPlugin {
 	}
 
 	protected void bind() {
-		ioExecutor.execute(new Runnable() {
+		ioExecutor.execute(() -> {
-			@Override
+			if (!running) return;
-			public void run() {
+			ServerSocket ss = null;
-				if (!running) return;
+			for (InetSocketAddress addr : getLocalSocketAddresses()) {
-				ServerSocket ss = null;
+				try {
-				for (InetSocketAddress addr : getLocalSocketAddresses()) {
+					ss = new ServerSocket();
-					try {
+					ss.bind(addr);
-						ss = new ServerSocket();
+					break;
-						ss.bind(addr);
+				} catch (IOException e) {
-						break;
+					if (LOG.isLoggable(INFO))
-					} catch (IOException e) {
+						LOG.info("Failed to bind " + scrubSocketAddress(addr));
-						if (LOG.isLoggable(INFO))
-							LOG.info("Failed to bind " +
-									scrubSocketAddress(addr));
-						tryToClose(ss);
-					}
-				}
-				if (ss == null || !ss.isBound()) {
-					LOG.info("Could not bind server socket");
-					return;
-				}
-				if (!running) {
 					tryToClose(ss);
-					return;
 				}
-				socket = ss;
-				backoff.reset();
-				InetSocketAddress local =
-						(InetSocketAddress) ss.getLocalSocketAddress();
-				setLocalSocketAddress(local);
-				if (LOG.isLoggable(INFO))
-					LOG.info("Listening on " + scrubSocketAddress(local));
-				callback.transportEnabled();
-				acceptContactConnections();
 			}
+			if (ss == null || !ss.isBound()) {
+				LOG.info("Could not bind server socket");
+				return;
+			}
+			if (!running) {
+				tryToClose(ss);
+				return;
+			}
+			socket = ss;
+			backoff.reset();
+			InetSocketAddress local =
+					(InetSocketAddress) ss.getLocalSocketAddress();
+			setLocalSocketAddress(local);
+			if (LOG.isLoggable(INFO))
+				LOG.info("Listening on " + scrubSocketAddress(local));
+			callback.transportEnabled();
+			acceptContactConnections();
 		});
 	}
 
@@ -218,17 +214,13 @@ abstract class TcpPlugin implements DuplexPlugin {
 		}
 	}
 
-	private void connectAndCallBack(final ContactId c,
+	private void connectAndCallBack(ContactId c, TransportProperties p) {
-			final TransportProperties p) {
+		ioExecutor.execute(() -> {
-		ioExecutor.execute(new Runnable() {
+			if (!isRunning()) return;
-			@Override
+			DuplexTransportConnection d = createConnection(p);
-			public void run() {
+			if (d != null) {
-				if (!isRunning()) return;
+				backoff.reset();
-				DuplexTransportConnection d = createConnection(p);
+				callback.outgoingConnectionCreated(c, d);
-				if (d != null) {
-					backoff.reset();
-					callback.outgoingConnectionCreated(c, d);
-				}
 			}
 		});
 	}
@@ -317,7 +309,7 @@ abstract class TcpPlugin implements DuplexPlugin {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			return Collections.emptyList();
 		}
-		List<InetAddress> addrs = new ArrayList<InetAddress>();
+		List<InetAddress> addrs = new ArrayList<>();
 		for (NetworkInterface iface : ifaces)
 			addrs.addAll(Collections.list(iface.getInetAddresses()));
 		return addrs;

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/WanTcpPlugin.java

@@ -43,7 +43,7 @@ class WanTcpPlugin extends TcpPlugin {
 		// Use the same address and port as last time if available
 		TransportProperties p = callback.getLocalProperties();
 		InetSocketAddress old = parseSocketAddress(p.get(PROP_IP_PORT));
-		List<InetSocketAddress> addrs = new LinkedList<InetSocketAddress>();
+		List<InetSocketAddress> addrs = new LinkedList<>();
 		for (InetAddress a : getLocalIpAddresses()) {
 			if (isAcceptableAddress(a)) {
 				// If this is the old address, try to use the same port

bramble-core/src/main/java/org/briarproject/bramble/properties/PropertiesModule.java

@@ -40,9 +40,12 @@ public class PropertiesModule {
 	@Provides
 	@Singleton
 	TransportPropertyManager getTransportPropertyManager(
-			LifecycleManager lifecycleManager, ContactManager contactManager,
+			LifecycleManager lifecycleManager,
+			ValidationManager validationManager, ContactManager contactManager,
 			TransportPropertyManagerImpl transportPropertyManager) {
 		lifecycleManager.registerClient(transportPropertyManager);
+		validationManager.registerIncomingMessageHook(CLIENT_ID,
+				transportPropertyManager);
 		contactManager.registerAddContactHook(transportPropertyManager);
 		contactManager.registerRemoveContactHook(transportPropertyManager);
 		return transportPropertyManager;

bramble-core/src/main/java/org/briarproject/bramble/properties/TransportPropertyManagerImpl.java

@@ -9,8 +9,10 @@ import org.briarproject.bramble.api.contact.ContactManager.AddContactHook;
 import org.briarproject.bramble.api.contact.ContactManager.RemoveContactHook;
 import org.briarproject.bramble.api.data.BdfDictionary;
 import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.data.MetadataParser;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
@@ -19,8 +21,10 @@ import org.briarproject.bramble.api.properties.TransportPropertyManager;
 import org.briarproject.bramble.api.sync.Client;
 import org.briarproject.bramble.api.sync.Group;
 import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.sync.InvalidMessageException;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.bramble.api.sync.ValidationManager.IncomingMessageHook;
 import org.briarproject.bramble.api.system.Clock;
 
 import java.util.HashMap;
@@ -36,23 +40,26 @@ import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
 @Immutable
 @NotNullByDefault
 class TransportPropertyManagerImpl implements TransportPropertyManager,
-		Client, AddContactHook, RemoveContactHook {
+		Client, AddContactHook, RemoveContactHook, IncomingMessageHook {
 
 	private final DatabaseComponent db;
 	private final ClientHelper clientHelper;
+	private final MetadataParser metadataParser;
 	private final ContactGroupFactory contactGroupFactory;
 	private final Clock clock;
 	private final Group localGroup;
 
 	@Inject
 	TransportPropertyManagerImpl(DatabaseComponent db,
-			ClientHelper clientHelper, ContactGroupFactory contactGroupFactory,
+			ClientHelper clientHelper, MetadataParser metadataParser,
-			Clock clock) {
+			ContactGroupFactory contactGroupFactory, Clock clock) {
 		this.db = db;
 		this.clientHelper = clientHelper;
+		this.metadataParser = metadataParser;
 		this.contactGroupFactory = contactGroupFactory;
 		this.clock = clock;
-		localGroup = contactGroupFactory.createLocalGroup(CLIENT_ID);
+		localGroup = contactGroupFactory.createLocalGroup(CLIENT_ID,
+				CLIENT_VERSION);
 	}
 
 	@Override
@@ -84,6 +91,31 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 		db.removeGroup(txn, getContactGroup(c));
 	}
 
+	@Override
+	public boolean incomingMessage(Transaction txn, Message m, Metadata meta)
+			throws DbException, InvalidMessageException {
+		try {
+			// Find the latest update for this transport, if any
+			BdfDictionary d = metadataParser.parse(meta);
+			TransportId t = new TransportId(d.getString("transportId"));
+			LatestUpdate latest = findLatest(txn, m.getGroupId(), t, false);
+			if (latest != null) {
+				if (d.getLong("version") > latest.version) {
+					// This update is newer - delete the previous update
+					db.deleteMessage(txn, latest.messageId);
+					db.deleteMessageMetadata(txn, latest.messageId);
+				} else {
+					// We've already received a newer update - delete this one
+					db.deleteMessage(txn, m.getId());
+					db.deleteMessageMetadata(txn, m.getId());
+				}
+			}
+		} catch (FormatException e) {
+			throw new InvalidMessageException(e);
+		}
+		return false;
+	}
+
 	@Override
 	public void addRemoteProperties(Transaction txn, ContactId c,
 			Map<TransportId, TransportProperties> props) throws DbException {
@@ -112,11 +144,9 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	public Map<TransportId, TransportProperties> getLocalProperties(
 			Transaction txn) throws DbException {
 		try {
-			Map<TransportId, TransportProperties> local =
+			Map<TransportId, TransportProperties> local = new HashMap<>();
-					new HashMap<TransportId, TransportProperties>();
 			// Find the latest local update for each transport
-			Map<TransportId, LatestUpdate> latest = findLatest(txn,
+			Map<TransportId, LatestUpdate> latest = findLatestLocal(txn);
-					localGroup.getId(), true);
 			// Retrieve and parse the latest local properties
 			for (Entry<TransportId, LatestUpdate> e : latest.entrySet()) {
 				BdfList message = clientHelper.getMessageAsList(txn,
@@ -160,8 +190,7 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	@Override
 	public Map<ContactId, TransportProperties> getRemoteProperties(
 			TransportId t) throws DbException {
-		Map<ContactId, TransportProperties> remote =
+		Map<ContactId, TransportProperties> remote = new HashMap<>();
-				new HashMap<ContactId, TransportProperties>();
 		Transaction txn = db.startTransaction(true);
 		try {
 			for (Contact c : db.getContacts(txn))
@@ -234,6 +263,9 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 					long version = latest == null ? 1 : latest.version + 1;
 					storeMessage(txn, localGroup.getId(), t, merged, version,
 							true, false);
+					// Delete the previous update, if any
+					if (latest != null)
+						db.removeMessage(txn, latest.messageId);
 					// Store the merged properties in each contact's group
 					for (Contact c : db.getContacts(txn)) {
 						Group g = getContactGroup(c);
@@ -241,6 +273,9 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 						version = latest == null ? 1 : latest.version + 1;
 						storeMessage(txn, g.getId(), t, merged, version,
 								true, true);
+						// Delete the previous update, if any
+						if (latest != null)
+							db.removeMessage(txn, latest.messageId);
 					}
 				}
 				db.commitTransaction(txn);
@@ -253,7 +288,8 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	}
 
 	private Group getContactGroup(Contact c) {
-		return contactGroupFactory.createContactGroup(CLIENT_ID, c);
+		return contactGroupFactory.createContactGroup(CLIENT_ID,
+				CLIENT_VERSION, c);
 	}
 
 	private void storeMessage(Transaction txn, GroupId g, TransportId t,
@@ -278,21 +314,16 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 		return BdfList.of(t.getString(), version, p);
 	}
 
-	private Map<TransportId, LatestUpdate> findLatest(Transaction txn,
+	private Map<TransportId, LatestUpdate> findLatestLocal(Transaction txn)
-			GroupId g, boolean local) throws DbException, FormatException {
+			throws DbException, FormatException {
-		Map<TransportId, LatestUpdate> latestUpdates =
+		Map<TransportId, LatestUpdate> latestUpdates = new HashMap<>();
-				new HashMap<TransportId, LatestUpdate>();
+		Map<MessageId, BdfDictionary> metadata = clientHelper
-		Map<MessageId, BdfDictionary> metadata =
+				.getMessageMetadataAsDictionary(txn, localGroup.getId());
-				clientHelper.getMessageMetadataAsDictionary(txn, g);
 		for (Entry<MessageId, BdfDictionary> e : metadata.entrySet()) {
 			BdfDictionary meta = e.getValue();
-			if (meta.getBoolean("local") == local) {
+			TransportId t = new TransportId(meta.getString("transportId"));
-				TransportId t = new TransportId(meta.getString("transportId"));
+			long version = meta.getLong("version");
-				long version = meta.getLong("version");
+			latestUpdates.put(t, new LatestUpdate(e.getKey(), version));
-				LatestUpdate latest = latestUpdates.get(t);
-				if (latest == null || version > latest.version)
-					latestUpdates.put(t, new LatestUpdate(e.getKey(), version));
-			}
 		}
 		return latestUpdates;
 	}
@@ -300,19 +331,16 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	@Nullable
 	private LatestUpdate findLatest(Transaction txn, GroupId g, TransportId t,
 			boolean local) throws DbException, FormatException {
-		LatestUpdate latest = null;
 		Map<MessageId, BdfDictionary> metadata =
 				clientHelper.getMessageMetadataAsDictionary(txn, g);
 		for (Entry<MessageId, BdfDictionary> e : metadata.entrySet()) {
 			BdfDictionary meta = e.getValue();
 			if (meta.getString("transportId").equals(t.getString())
 					&& meta.getBoolean("local") == local) {
-				long version = meta.getLong("version");
+				return new LatestUpdate(e.getKey(), meta.getLong("version"));
-				if (latest == null || version > latest.version)
-					latest = new LatestUpdate(e.getKey(), version);
 			}
 		}
-		return latest;
+		return null;
 	}
 
 	private TransportProperties parseProperties(BdfList message)

bramble-core/src/main/java/org/briarproject/bramble/reliability/Receiver.java

@@ -41,7 +41,7 @@ class Receiver implements ReadHandler {
 	Receiver(Clock clock, Sender sender) {
 		this.sender = sender;
 		this.clock = clock;
-		dataFrames = new TreeSet<Data>(new SequenceNumberComparator());
+		dataFrames = new TreeSet<>(new SequenceNumberComparator());
 	}
 
 	Data read() throws IOException, InterruptedException {

bramble-core/src/main/java/org/briarproject/bramble/reliability/ReliabilityLayerImpl.java

@@ -42,48 +42,44 @@ class ReliabilityLayerImpl implements ReliabilityLayer, WriteHandler {
 		this.executor = executor;
 		this.clock = clock;
 		this.writeHandler = writeHandler;
-		writes = new LinkedBlockingQueue<byte[]>();
+		writes = new LinkedBlockingQueue<>();
 	}
 
 	@Override
 	public void start() {
 		SlipEncoder encoder = new SlipEncoder(this);
-		final Sender sender = new Sender(clock, encoder);
+		Sender sender = new Sender(clock, encoder);
 		receiver = new Receiver(clock, sender);
 		decoder = new SlipDecoder(receiver, Data.MAX_LENGTH);
 		inputStream = new ReceiverInputStream(receiver);
 		outputStream = new SenderOutputStream(sender);
 		running = true;
-		executor.execute(new Runnable() {
+		executor.execute(() -> {
-			@Override
+			long now = clock.currentTimeMillis();
-			public void run() {
+			long next = now + TICK_INTERVAL;
-				long now = clock.currentTimeMillis();
+			try {
-				long next = now + TICK_INTERVAL;
+				while (running) {
-				try {
+					byte[] b = null;
-					while (running) {
+					while (now < next && b == null) {
-						byte[] b = null;
+						b = writes.poll(next - now, MILLISECONDS);
-						while (now < next && b == null) {
+						if (!running) return;
-							b = writes.poll(next - now, MILLISECONDS);
+						now = clock.currentTimeMillis();
-							if (!running) return;
+					}
-							now = clock.currentTimeMillis();
+					if (b == null) {
-						}
+						sender.tick();
-						if (b == null) {
+						while (next <= now) next += TICK_INTERVAL;
-							sender.tick();
+					} else {
-							while (next <= now) next += TICK_INTERVAL;
+						if (b.length == 0) return; // Poison pill
-						} else {
+						writeHandler.handleWrite(b);
-							if (b.length == 0) return; // Poison pill
-							writeHandler.handleWrite(b);
-						}
 					}
-				} catch (InterruptedException e) {
-					LOG.warning("Interrupted while waiting to write");
-					Thread.currentThread().interrupt();
-					running = false;
-				} catch (IOException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
-					running = false;
 				}
+			} catch (InterruptedException e) {
+				LOG.warning("Interrupted while waiting to write");
+				Thread.currentThread().interrupt();
+				running = false;
+			} catch (IOException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+				running = false;
 			}
 		});
 	}

bramble-core/src/main/java/org/briarproject/bramble/reliability/Sender.java

@@ -46,7 +46,7 @@ class Sender {
 	Sender(Clock clock, WriteHandler writeHandler) {
 		this.clock = clock;
 		this.writeHandler = writeHandler;
-		outstanding = new LinkedList<Outstanding>();
+		outstanding = new LinkedList<>();
 	}
 
 	void sendAck(long sequenceNumber, int windowSize) throws IOException {
@@ -136,7 +136,7 @@ class Sender {
 					if (now - o.lastTransmitted > rto) {
 						it.remove();
 						if (retransmit == null)
-							retransmit = new ArrayList<Outstanding>();
+							retransmit = new ArrayList<>();
 						retransmit.add(o);
 						// Update the retransmission timeout
 						rto <<= 1;

bramble-core/src/main/java/org/briarproject/bramble/sync/DuplexOutgoingSession.java

@@ -54,12 +54,7 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 	private static final Logger LOG =
 			Logger.getLogger(DuplexOutgoingSession.class.getName());
 
-	private static final ThrowingRunnable<IOException> CLOSE =
+	private static final ThrowingRunnable<IOException> CLOSE = () -> {};
-			new ThrowingRunnable<IOException>() {
-				@Override
-				public void run() {
-				}
-			};
 
 	private final DatabaseComponent db;
 	private final Executor dbExecutor;
@@ -83,7 +78,7 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		this.maxLatency = maxLatency;
 		this.maxIdleTime = maxIdleTime;
 		this.recordWriter = recordWriter;
-		writerTasks = new LinkedBlockingQueue<ThrowingRunnable<IOException>>();
+		writerTasks = new LinkedBlockingQueue<>();
 	}
 
 	@IoExecutor

bramble-core/src/main/java/org/briarproject/bramble/sync/GroupFactoryImpl.java

@@ -6,11 +6,16 @@ import org.briarproject.bramble.api.sync.ClientId;
 import org.briarproject.bramble.api.sync.Group;
 import org.briarproject.bramble.api.sync.GroupFactory;
 import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.util.ByteUtils;
 import org.briarproject.bramble.util.StringUtils;
 
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
+import static org.briarproject.bramble.api.sync.GroupId.LABEL;
+import static org.briarproject.bramble.api.sync.SyncConstants.PROTOCOL_VERSION;
+import static org.briarproject.bramble.util.ByteUtils.INT_32_BYTES;
+
 @Immutable
 @NotNullByDefault
 class GroupFactoryImpl implements GroupFactory {
@@ -23,9 +28,12 @@ class GroupFactoryImpl implements GroupFactory {
 	}
 
 	@Override
-	public Group createGroup(ClientId c, byte[] descriptor) {
+	public Group createGroup(ClientId c, int clientVersion, byte[] descriptor) {
-		byte[] hash = crypto.hash(GroupId.LABEL,
+		byte[] clientVersionBytes = new byte[INT_32_BYTES];
-				StringUtils.toUtf8(c.getString()), descriptor);
+		ByteUtils.writeUint32(clientVersion, clientVersionBytes, 0);
+		byte[] hash = crypto.hash(LABEL, new byte[] {PROTOCOL_VERSION},
+				StringUtils.toUtf8(c.getString()), clientVersionBytes,
+				descriptor);
 		return new Group(new GroupId(hash), c, descriptor);
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/sync/MessageFactoryImpl.java

@@ -12,8 +12,10 @@ import org.briarproject.bramble.util.ByteUtils;
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
+import static org.briarproject.bramble.api.sync.MessageId.LABEL;
 import static org.briarproject.bramble.api.sync.SyncConstants.MAX_MESSAGE_BODY_LENGTH;
 import static org.briarproject.bramble.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
+import static org.briarproject.bramble.api.sync.SyncConstants.PROTOCOL_VERSION;
 
 @Immutable
 @NotNullByDefault
@@ -32,9 +34,9 @@ class MessageFactoryImpl implements MessageFactory {
 			throw new IllegalArgumentException();
 		byte[] timeBytes = new byte[ByteUtils.INT_64_BYTES];
 		ByteUtils.writeUint64(timestamp, timeBytes, 0);
-		byte[] idHash =
+		byte[] hash = crypto.hash(LABEL, new byte[] {PROTOCOL_VERSION},
-				crypto.hash(MessageId.LABEL, g.getBytes(), timeBytes, body);
+				g.getBytes(), timeBytes, body);
-		MessageId id = new MessageId(idHash);
+		MessageId id = new MessageId(hash);
 		byte[] raw = new byte[MESSAGE_HEADER_LENGTH + body.length];
 		System.arraycopy(g.getBytes(), 0, raw, 0, UniqueId.LENGTH);
 		ByteUtils.writeUint64(timestamp, raw, UniqueId.LENGTH);

bramble-core/src/main/java/org/briarproject/bramble/sync/RecordReaderImpl.java

@@ -116,7 +116,7 @@ class RecordReaderImpl implements RecordReader {
 	private List<MessageId> readMessageIds() throws IOException {
 		if (payloadLength == 0) throw new FormatException();
 		if (payloadLength % UniqueId.LENGTH != 0) throw new FormatException();
-		List<MessageId> ids = new ArrayList<MessageId>();
+		List<MessageId> ids = new ArrayList<>();
 		for (int off = 0; off < payloadLength; off += UniqueId.LENGTH) {
 			byte[] id = new byte[UniqueId.LENGTH];
 			System.arraycopy(payload, off, id, 0, UniqueId.LENGTH);

bramble-core/src/main/java/org/briarproject/bramble/sync/SimplexOutgoingSession.java

@@ -43,12 +43,7 @@ class SimplexOutgoingSession implements SyncSession, EventListener {
 	private static final Logger LOG =
 			Logger.getLogger(SimplexOutgoingSession.class.getName());
 
-	private static final ThrowingRunnable<IOException> CLOSE =
+	private static final ThrowingRunnable<IOException> CLOSE = () -> {};
-			new ThrowingRunnable<IOException>() {
-				@Override
-				public void run() {
-				}
-			};
 
 	private final DatabaseComponent db;
 	private final Executor dbExecutor;
@@ -71,7 +66,7 @@ class SimplexOutgoingSession implements SyncSession, EventListener {
 		this.maxLatency = maxLatency;
 		this.recordWriter = recordWriter;
 		outstandingQueries = new AtomicInteger(2); // One per type of record
-		writerTasks = new LinkedBlockingQueue<ThrowingRunnable<IOException>>();
+		writerTasks = new LinkedBlockingQueue<>();
 	}
 
 	@IoExecutor

bramble-core/src/main/java/org/briarproject/bramble/sync/ValidationManagerImpl.java

@@ -64,8 +64,8 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		this.dbExecutor = dbExecutor;
 		this.validationExecutor = validationExecutor;
 		this.messageFactory = messageFactory;
-		validators = new ConcurrentHashMap<ClientId, MessageValidator>();
+		validators = new ConcurrentHashMap<>();
-		hooks = new ConcurrentHashMap<ClientId, IncomingMessageHook>();
+		hooks = new ConcurrentHashMap<>();
 	}
 
 	@Override
@@ -93,19 +93,14 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		hooks.put(c, hook);
 	}
 
-	private void validateOutstandingMessagesAsync(final ClientId c) {
+	private void validateOutstandingMessagesAsync(ClientId c) {
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> validateOutstandingMessages(c));
-			@Override
-			public void run() {
-				validateOutstandingMessages(c);
-			}
-		});
 	}
 
 	@DatabaseExecutor
 	private void validateOutstandingMessages(ClientId c) {
 		try {
-			Queue<MessageId> unvalidated = new LinkedList<MessageId>();
+			Queue<MessageId> unvalidated = new LinkedList<>();
 			Transaction txn = db.startTransaction(true);
 			try {
 				unvalidated.addAll(db.getMessagesToValidate(txn, c));
@@ -119,14 +114,9 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		}
 	}
 
-	private void validateNextMessageAsync(final Queue<MessageId> unvalidated) {
+	private void validateNextMessageAsync(Queue<MessageId> unvalidated) {
 		if (unvalidated.isEmpty()) return;
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> validateNextMessage(unvalidated));
-			@Override
-			public void run() {
-				validateNextMessage(unvalidated);
-			}
-		});
 	}
 
 	@DatabaseExecutor
@@ -158,19 +148,14 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		}
 	}
 
-	private void deliverOutstandingMessagesAsync(final ClientId c) {
+	private void deliverOutstandingMessagesAsync(ClientId c) {
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> deliverOutstandingMessages(c));
-			@Override
-			public void run() {
-				deliverOutstandingMessages(c);
-			}
-		});
 	}
 
 	@DatabaseExecutor
 	private void deliverOutstandingMessages(ClientId c) {
 		try {
-			Queue<MessageId> pending = new LinkedList<MessageId>();
+			Queue<MessageId> pending = new LinkedList<>();
 			Transaction txn = db.startTransaction(true);
 			try {
 				pending.addAll(db.getPendingMessages(txn, c));
@@ -184,15 +169,9 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		}
 	}
 
-	private void deliverNextPendingMessageAsync(
+	private void deliverNextPendingMessageAsync(Queue<MessageId> pending) {
-			final Queue<MessageId> pending) {
 		if (pending.isEmpty()) return;
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> deliverNextPendingMessage(pending));
-			@Override
-			public void run() {
-				deliverNextPendingMessage(pending);
-			}
-		});
 	}
 
 	@DatabaseExecutor
@@ -229,8 +208,7 @@ class ValidationManagerImpl implements ValidationManager, Service,
 							pending.addAll(getPendingDependents(txn, id));
 							if (result.share) {
 								db.setMessageShared(txn, id);
-								toShare = new LinkedList<MessageId>(
+								toShare = new LinkedList<>(states.keySet());
-										states.keySet());
 							}
 						} else {
 							invalidate = getDependentsToInvalidate(txn, id);
@@ -255,13 +233,8 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		}
 	}
 
-	private void validateMessageAsync(final Message m, final Group g) {
+	private void validateMessageAsync(Message m, Group g) {
-		validationExecutor.execute(new Runnable() {
+		validationExecutor.execute(() -> validateMessage(m, g));
-			@Override
-			public void run() {
-				validateMessage(m, g);
-			}
-		});
 	}
 
 	@ValidationExecutor
@@ -277,21 +250,16 @@ class ValidationManagerImpl implements ValidationManager, Service,
 			} catch (InvalidMessageException e) {
 				if (LOG.isLoggable(INFO))
 					LOG.log(INFO, e.toString(), e);
-				Queue<MessageId> invalidate = new LinkedList<MessageId>();
+				Queue<MessageId> invalidate = new LinkedList<>();
 				invalidate.add(m.getId());
 				invalidateNextMessageAsync(invalidate);
 			}
 		}
 	}
 
-	private void storeMessageContextAsync(final Message m, final ClientId c,
+	private void storeMessageContextAsync(Message m, ClientId c,
-			final MessageContext result) {
+			MessageContext result) {
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> storeMessageContext(m, c, result));
-			@Override
-			public void run() {
-				storeMessageContext(m, c, result);
-			}
-		});
 	}
 
 	@DatabaseExecutor
@@ -331,8 +299,7 @@ class ValidationManagerImpl implements ValidationManager, Service,
 							pending = getPendingDependents(txn, id);
 							if (result.share) {
 								db.setMessageShared(txn, id);
-								toShare =
+								toShare = new LinkedList<>(dependencies);
-										new LinkedList<MessageId>(dependencies);
 							}
 						} else {
 							invalidate = getDependentsToInvalidate(txn, id);
@@ -378,7 +345,7 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private Queue<MessageId> getPendingDependents(Transaction txn, MessageId m)
 			throws DbException {
-		Queue<MessageId> pending = new LinkedList<MessageId>();
+		Queue<MessageId> pending = new LinkedList<>();
 		Map<MessageId, State> states = db.getMessageDependents(txn, m);
 		for (Entry<MessageId, State> e : states.entrySet()) {
 			if (e.getValue() == PENDING) pending.add(e.getKey());
@@ -386,19 +353,14 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		return pending;
 	}
 
-	private void shareOutstandingMessagesAsync(final ClientId c) {
+	private void shareOutstandingMessagesAsync(ClientId c) {
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> shareOutstandingMessages(c));
-			@Override
-			public void run() {
-				shareOutstandingMessages(c);
-			}
-		});
 	}
 
 	@DatabaseExecutor
 	private void shareOutstandingMessages(ClientId c) {
 		try {
-			Queue<MessageId> toShare = new LinkedList<MessageId>();
+			Queue<MessageId> toShare = new LinkedList<>();
 			Transaction txn = db.startTransaction(true);
 			try {
 				toShare.addAll(db.getMessagesToShare(txn, c));
@@ -418,14 +380,9 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	 * This method should only be called for messages that have all their
 	 * dependencies delivered and have been delivered themselves.
 	 */
-	private void shareNextMessageAsync(final Queue<MessageId> toShare) {
+	private void shareNextMessageAsync(Queue<MessageId> toShare) {
 		if (toShare.isEmpty()) return;
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> shareNextMessage(toShare));
-			@Override
-			public void run() {
-				shareNextMessage(toShare);
-			}
-		});
 	}
 
 	@DatabaseExecutor
@@ -452,14 +409,9 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		}
 	}
 
-	private void invalidateNextMessageAsync(final Queue<MessageId> invalidate) {
+	private void invalidateNextMessageAsync(Queue<MessageId> invalidate) {
 		if (invalidate.isEmpty()) return;
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> invalidateNextMessage(invalidate));
-			@Override
-			public void run() {
-				invalidateNextMessage(invalidate);
-			}
-		});
 	}
 
 	@DatabaseExecutor
@@ -496,7 +448,7 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private Queue<MessageId> getDependentsToInvalidate(Transaction txn,
 			MessageId m) throws DbException {
-		Queue<MessageId> invalidate = new LinkedList<MessageId>();
+		Queue<MessageId> invalidate = new LinkedList<>();
 		Map<MessageId, State> states = db.getMessageDependents(txn, m);
 		for (Entry<MessageId, State> e : states.entrySet()) {
 			if (e.getValue() != INVALID) invalidate.add(e.getKey());
@@ -514,17 +466,12 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		}
 	}
 
-	private void loadGroupAndValidateAsync(final Message m) {
+	private void loadGroupAndValidateAsync(Message m) {
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> loadGroupAndValidate(m));
-			@Override
-			public void run() {
-				loadGroupAndValidate(m);
-			}
-		});
 	}
 
 	@DatabaseExecutor
-	private void loadGroupAndValidate(final Message m) {
+	private void loadGroupAndValidate(Message m) {
 		try {
 			Group g;
 			Transaction txn = db.startTransaction(true);

bramble-core/src/main/java/org/briarproject/bramble/transport/KeyManagerImpl.java

@@ -58,15 +58,14 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 		this.pluginConfig = pluginConfig;
 		this.transportKeyManagerFactory = transportKeyManagerFactory;
 		// Use a ConcurrentHashMap as a thread-safe set
-		activeContacts = new ConcurrentHashMap<ContactId, Boolean>();
+		activeContacts = new ConcurrentHashMap<>();
-		managers = new ConcurrentHashMap<TransportId, TransportKeyManager>();
+		managers = new ConcurrentHashMap<>();
 	}
 
 	@Override
 	public void startService() throws ServiceException {
 		if (used.getAndSet(true)) throw new IllegalStateException();
-		Map<TransportId, Integer> transports =
+		Map<TransportId, Integer> transports = new HashMap<>();
-				new HashMap<TransportId, Integer>();
 		for (SimplexPluginFactory f : pluginConfig.getSimplexFactories())
 			transports.put(f.getId(), f.getMaxLatency());
 		for (DuplexPluginFactory f : pluginConfig.getDuplexFactories())
@@ -156,14 +155,10 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 		}
 	}
 
-	private void removeContact(final ContactId c) {
+	private void removeContact(ContactId c) {
 		activeContacts.remove(c);
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> {
-			@Override
+			for (TransportKeyManager m : managers.values()) m.removeContact(c);
-			public void run() {
-				for (TransportKeyManager m : managers.values())
-					m.removeContact(c);
-			}
 		});
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/transport/ReorderingWindow.java

@@ -45,7 +45,7 @@ class ReorderingWindow {
 	}
 
 	List<Long> getUnseen() {
-		List<Long> unseen = new ArrayList<Long>(seen.length);
+		List<Long> unseen = new ArrayList<>(seen.length);
 		for (int i = 0; i < seen.length; i++)
 			if (!seen[i]) unseen.add(base + i);
 		return unseen;
@@ -69,8 +69,8 @@ class ReorderingWindow {
 			return new Change(added, removed);
 		}
 		// Record the elements that will be added and removed
-		List<Long> added = new ArrayList<Long>(slide);
+		List<Long> added = new ArrayList<>(slide);
-		List<Long> removed = new ArrayList<Long>(slide);
+		List<Long> removed = new ArrayList<>(slide);
 		for (int i = 0; i < slide; i++) {
 			if (!seen[i]) removed.add(base + i);
 			added.add(base + seen.length + i);

bramble-core/src/main/java/org/briarproject/bramble/transport/TransportKeyManagerFactoryImpl.java

@@ -1,6 +1,6 @@
 package org.briarproject.bramble.transport;
 
-import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.TransportCrypto;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
@@ -20,17 +20,18 @@ class TransportKeyManagerFactoryImpl implements
 		TransportKeyManagerFactory {
 
 	private final DatabaseComponent db;
-	private final CryptoComponent crypto;
+	private final TransportCrypto transportCrypto;
 	private final Executor dbExecutor;
 	private final ScheduledExecutorService scheduler;
 	private final Clock clock;
 
 	@Inject
-	TransportKeyManagerFactoryImpl(DatabaseComponent db, CryptoComponent crypto,
+	TransportKeyManagerFactoryImpl(DatabaseComponent db,
+			TransportCrypto transportCrypto,
 			@DatabaseExecutor Executor dbExecutor,
 			@Scheduler ScheduledExecutorService scheduler, Clock clock) {
 		this.db = db;
-		this.crypto = crypto;
+		this.transportCrypto = transportCrypto;
 		this.dbExecutor = dbExecutor;
 		this.scheduler = scheduler;
 		this.clock = clock;
@@ -39,8 +40,8 @@ class TransportKeyManagerFactoryImpl implements
 	@Override
 	public TransportKeyManager createTransportKeyManager(
 			TransportId transportId, long maxLatency) {
-		return new TransportKeyManagerImpl(db, crypto, dbExecutor, scheduler,
+		return new TransportKeyManagerImpl(db, transportCrypto, dbExecutor,
-				clock, transportId, maxLatency);
+				scheduler, clock, transportId, maxLatency);
 	}
 
 }

bramble-core/src/main/java/org/briarproject/bramble/transport/TransportKeyManagerImpl.java

@@ -2,8 +2,8 @@ package org.briarproject.bramble.transport;
 
 import org.briarproject.bramble.api.Bytes;
 import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.crypto.TransportCrypto;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
@@ -41,7 +41,7 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 			Logger.getLogger(TransportKeyManagerImpl.class.getName());
 
 	private final DatabaseComponent db;
-	private final CryptoComponent crypto;
+	private final TransportCrypto transportCrypto;
 	private final Executor dbExecutor;
 	private final ScheduledExecutorService scheduler;
 	private final Clock clock;
@@ -54,20 +54,21 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 	private final Map<ContactId, MutableOutgoingKeys> outContexts;
 	private final Map<ContactId, MutableTransportKeys> keys;
 
-	TransportKeyManagerImpl(DatabaseComponent db, CryptoComponent crypto,
+	TransportKeyManagerImpl(DatabaseComponent db,
-			Executor dbExecutor, @Scheduler ScheduledExecutorService scheduler,
+			TransportCrypto transportCrypto, Executor dbExecutor,
-			Clock clock, TransportId transportId, long maxLatency) {
+			@Scheduler ScheduledExecutorService scheduler, Clock clock,
+			TransportId transportId, long maxLatency) {
 		this.db = db;
-		this.crypto = crypto;
+		this.transportCrypto = transportCrypto;
 		this.dbExecutor = dbExecutor;
 		this.scheduler = scheduler;
 		this.clock = clock;
 		this.transportId = transportId;
 		rotationPeriodLength = maxLatency + MAX_CLOCK_DIFFERENCE;
 		lock = new ReentrantLock();
-		inContexts = new HashMap<Bytes, TagContext>();
+		inContexts = new HashMap<>();
-		outContexts = new HashMap<ContactId, MutableOutgoingKeys>();
+		outContexts = new HashMap<>();
-		keys = new HashMap<ContactId, MutableTransportKeys>();
+		keys = new HashMap<>();
 	}
 
 	@Override
@@ -99,7 +100,8 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 		for (Entry<ContactId, TransportKeys> e : keys.entrySet()) {
 			ContactId c = e.getKey();
 			TransportKeys k = e.getValue();
-			TransportKeys k1 = crypto.rotateTransportKeys(k, rotationPeriod);
+			TransportKeys k1 =
+					transportCrypto.rotateTransportKeys(k, rotationPeriod);
 			if (k1.getRotationPeriod() > k.getRotationPeriod())
 				rotationResult.rotated.put(c, k1);
 			rotationResult.current.put(c, k1);
@@ -127,39 +129,29 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 		for (long streamNumber : inKeys.getWindow().getUnseen()) {
 			TagContext tagCtx = new TagContext(c, inKeys, streamNumber);
 			byte[] tag = new byte[TAG_LENGTH];
-			crypto.encodeTag(tag, inKeys.getTagKey(), PROTOCOL_VERSION,
+			transportCrypto.encodeTag(tag, inKeys.getTagKey(), PROTOCOL_VERSION,
 					streamNumber);
 			inContexts.put(new Bytes(tag), tagCtx);
 		}
 	}
 
 	private void scheduleKeyRotation(long now) {
-		Runnable task = new Runnable() {
-			@Override
-			public void run() {
-				rotateKeys();
-			}
-		};
 		long delay = rotationPeriodLength - now % rotationPeriodLength;
-		scheduler.schedule(task, delay, MILLISECONDS);
+		scheduler.schedule((Runnable) this::rotateKeys, delay, MILLISECONDS);
 	}
 
 	private void rotateKeys() {
-		dbExecutor.execute(new Runnable() {
+		dbExecutor.execute(() -> {
-			@Override
+			try {
-			public void run() {
+				Transaction txn = db.startTransaction(false);
 				try {
-					Transaction txn = db.startTransaction(false);
+					rotateKeys(txn);
-					try {
+					db.commitTransaction(txn);
-						rotateKeys(txn);
+				} finally {
-						db.commitTransaction(txn);
+					db.endTransaction(txn);
-					} finally {
-						db.endTransaction(txn);
-					}
-				} catch (DbException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
 				}
+			} catch (DbException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			}
 		});
 	}
@@ -172,11 +164,11 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 			// Work out what rotation period the timestamp belongs to
 			long rotationPeriod = timestamp / rotationPeriodLength;
 			// Derive the transport keys
-			TransportKeys k = crypto.deriveTransportKeys(transportId, master,
+			TransportKeys k = transportCrypto.deriveTransportKeys(transportId,
-					rotationPeriod, alice);
+					master, rotationPeriod, alice);
 			// Rotate the keys to the current rotation period if necessary
 			rotationPeriod = clock.currentTimeMillis() / rotationPeriodLength;
-			k = crypto.rotateTransportKeys(k, rotationPeriod);
+			k = transportCrypto.rotateTransportKeys(k, rotationPeriod);
 			// Initialise mutable state for the contact
 			addKeys(c, new MutableTransportKeys(k));
 			// Write the keys back to the DB
@@ -244,8 +236,8 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 			// Add tags for any stream numbers added to the window
 			for (long streamNumber : change.getAdded()) {
 				byte[] addTag = new byte[TAG_LENGTH];
-				crypto.encodeTag(addTag, inKeys.getTagKey(), PROTOCOL_VERSION,
+				transportCrypto.encodeTag(addTag, inKeys.getTagKey(),
-						streamNumber);
+						PROTOCOL_VERSION, streamNumber);
 				inContexts.put(new Bytes(addTag), new TagContext(
 						tagCtx.contactId, inKeys, streamNumber));
 			}
@@ -253,7 +245,7 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 			for (long streamNumber : change.getRemoved()) {
 				if (streamNumber == tagCtx.streamNumber) continue;
 				byte[] removeTag = new byte[TAG_LENGTH];
-				crypto.encodeTag(removeTag, inKeys.getTagKey(),
+				transportCrypto.encodeTag(removeTag, inKeys.getTagKey(),
 						PROTOCOL_VERSION, streamNumber);
 				inContexts.remove(new Bytes(removeTag));
 			}
@@ -272,8 +264,7 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 		lock.lock();
 		try {
 			// Rotate the keys to the current rotation period
-			Map<ContactId, TransportKeys> snapshot =
+			Map<ContactId, TransportKeys> snapshot = new HashMap<>();
-					new HashMap<ContactId, TransportKeys>();
 			for (Entry<ContactId, MutableTransportKeys> e : keys.entrySet())
 				snapshot.put(e.getKey(), e.getValue().snapshot());
 			RotationResult rotationResult = rotateKeys(snapshot, now);
@@ -311,8 +302,8 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 		private final Map<ContactId, TransportKeys> current, rotated;
 
 		private RotationResult() {
-			current = new HashMap<ContactId, TransportKeys>();
+			current = new HashMap<>();
-			rotated = new HashMap<ContactId, TransportKeys>();
+			rotated = new HashMap<>();
 		}
 	}
 }

bramble-core/src/test/java/org/briarproject/bramble/PoliteExecutorTest.java

@@ -24,16 +24,13 @@ public class PoliteExecutorTest extends BrambleTestCase {
 		Executor delegate = Executors.newSingleThreadExecutor();
 		// Allow all the tasks to be delegated straight away
 		PoliteExecutor polite = new PoliteExecutor(TAG, delegate, TASKS * 2);
-		final List<Integer> list = new Vector<Integer>();
+		List<Integer> list = new Vector<>();
-		final CountDownLatch latch = new CountDownLatch(TASKS);
+		CountDownLatch latch = new CountDownLatch(TASKS);
 		for (int i = 0; i < TASKS; i++) {
-			final int result = i;
+			int result = i;
-			polite.execute(new Runnable() {
+			polite.execute(() -> {
-				@Override
+				list.add(result);
-				public void run() {
+				latch.countDown();
-					list.add(result);
-					latch.countDown();
-				}
 			});
 		}
 		// Wait for all the tasks to finish
@@ -49,16 +46,13 @@ public class PoliteExecutorTest extends BrambleTestCase {
 		Executor delegate = Executors.newSingleThreadExecutor();
 		// Allow two tasks to be delegated at a time
 		PoliteExecutor polite = new PoliteExecutor(TAG, delegate, 2);
-		final List<Integer> list = new Vector<Integer>();
+		List<Integer> list = new Vector<>();
-		final CountDownLatch latch = new CountDownLatch(TASKS);
+		CountDownLatch latch = new CountDownLatch(TASKS);
 		for (int i = 0; i < TASKS; i++) {
-			final int result = i;
+			int result = i;
-			polite.execute(new Runnable() {
+			polite.execute(() -> {
-				@Override
+				list.add(result);
-				public void run() {
+				latch.countDown();
-					list.add(result);
-					latch.countDown();
-				}
 			});
 		}
 		// Wait for all the tasks to finish
@@ -73,23 +67,20 @@ public class PoliteExecutorTest extends BrambleTestCase {
 		Executor delegate = Executors.newCachedThreadPool();
 		// Allow all the tasks to be delegated straight away
 		PoliteExecutor polite = new PoliteExecutor(TAG, delegate, TASKS * 2);
-		final List<Integer> list = new Vector<Integer>();
+		List<Integer> list = new Vector<>();
-		final CountDownLatch[] latches = new CountDownLatch[TASKS];
+		CountDownLatch[] latches = new CountDownLatch[TASKS];
 		for (int i = 0; i < TASKS; i++) latches[i] = new CountDownLatch(1);
 		for (int i = 0; i < TASKS; i++) {
-			final int result = i;
+			int result = i;
-			polite.execute(new Runnable() {
+			polite.execute(() -> {
-				@Override
+				try {
-				public void run() {
+					// Each task waits for the next task, if any, to finish
-					try {
+					if (result < TASKS - 1) latches[result + 1].await();
-						// Each task waits for the next task, if any, to finish
+					list.add(result);
-						if (result < TASKS - 1) latches[result + 1].await();
+				} catch (InterruptedException e) {
-						list.add(result);
+					fail();
-					} catch (InterruptedException e) {
-						fail();
-					}
-					latches[result].countDown();
 				}
+				latches[result].countDown();
 			});
 		}
 		// Wait for all the tasks to finish
@@ -104,22 +95,19 @@ public class PoliteExecutorTest extends BrambleTestCase {
 		Executor delegate = Executors.newCachedThreadPool();
 		// Allow one task to be delegated at a time
 		PoliteExecutor polite = new PoliteExecutor(TAG, delegate, 1);
-		final List<Integer> list = new Vector<Integer>();
+		List<Integer> list = new Vector<>();
-		final CountDownLatch latch = new CountDownLatch(TASKS);
+		CountDownLatch latch = new CountDownLatch(TASKS);
 		for (int i = 0; i < TASKS; i++) {
-			final int result = i;
+			int result = i;
-			polite.execute(new Runnable() {
+			polite.execute(() -> {
-				@Override
+				try {
-				public void run() {
+					// Each task runs faster than the previous task
-					try {
+					Thread.sleep(TASKS - result);
-						// Each task runs faster than the previous task
+					list.add(result);
-						Thread.sleep(TASKS - result);
+				} catch (InterruptedException e) {
-						list.add(result);
+					fail();
-					} catch (InterruptedException e) {
-						fail();
-					}
-					latch.countDown();
 				}
+				latch.countDown();
 			});
 		}
 		// Wait for all the tasks to finish

bramble-core/src/test/java/org/briarproject/bramble/client/BdfMessageValidatorTest.java

@@ -83,9 +83,9 @@ public class BdfMessageValidatorTest extends ValidatorTestCase {
 
 	@Test(expected = InvalidMessageException.class)
 	public void testRejectsTooShortMessage() throws Exception {
-		final byte[] invalidRaw = new byte[MESSAGE_HEADER_LENGTH];
+		byte[] invalidRaw = new byte[MESSAGE_HEADER_LENGTH];
 		// Use a mock message so the length of the raw message can be invalid
-		final Message invalidMessage = context.mock(Message.class);
+		Message invalidMessage = context.mock(Message.class);
 
 		context.checking(new Expectations() {{
 			oneOf(invalidMessage).getTimestamp();
@@ -101,8 +101,8 @@ public class BdfMessageValidatorTest extends ValidatorTestCase {
 
 	@Test
 	public void testAcceptsMinLengthMessage() throws Exception {
-		final byte[] shortRaw = new byte[MESSAGE_HEADER_LENGTH + 1];
+		byte[] shortRaw = new byte[MESSAGE_HEADER_LENGTH + 1];
-		final Message shortMessage =
+		Message shortMessage =
 				new Message(messageId, groupId, timestamp, shortRaw);
 
 		context.checking(new Expectations() {{

bramble-core/src/test/java/org/briarproject/bramble/client/ClientHelperImplTest.java

@@ -76,8 +76,8 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testAddLocalMessage() throws Exception {
-		final boolean shared = true;
+		boolean shared = true;
-		final Transaction txn = new Transaction(null, false);
+		Transaction txn = new Transaction(null, false);
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(false);
@@ -95,7 +95,7 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testCreateMessage() throws Exception {
-		final byte[] bytes = expectToByteArray(list);
+		byte[] bytes = expectToByteArray(list);
 
 		context.checking(new Expectations() {{
 			oneOf(messageFactory).createMessage(groupId, timestamp, bytes);
@@ -107,7 +107,7 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testGetMessageAsList() throws Exception {
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 
 		expectToList(true);
 		context.checking(new Expectations() {{
@@ -125,7 +125,7 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testGetGroupMetadataAsDictionary() throws Exception {
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
@@ -145,7 +145,7 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testGetMessageMetadataAsDictionary() throws Exception {
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
@@ -165,10 +165,9 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testGetMessageMetadataAsDictionaryMap() throws Exception {
-		final Map<MessageId, BdfDictionary> map =
+		Map<MessageId, BdfDictionary> map = new HashMap<>();
-				new HashMap<MessageId, BdfDictionary>();
 		map.put(messageId, dictionary);
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
@@ -188,14 +187,13 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testGetMessageMetadataAsDictionaryQuery() throws Exception {
-		final Map<MessageId, BdfDictionary> map =
+		Map<MessageId, BdfDictionary> map = new HashMap<>();
-				new HashMap<MessageId, BdfDictionary>();
 		map.put(messageId, dictionary);
-		final BdfDictionary query =
+		BdfDictionary query =
 				BdfDictionary.of(new BdfEntry("query", "me"));
-		final Metadata queryMetadata = new Metadata();
+		Metadata queryMetadata = new Metadata();
 		queryMetadata.put("query", getRandomBytes(42));
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
@@ -217,7 +215,7 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testMergeGroupMetadata() throws Exception {
-		final Transaction txn = new Transaction(null, false);
+		Transaction txn = new Transaction(null, false);
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(false);
@@ -235,7 +233,7 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testMergeMessageMetadata() throws Exception {
-		final Transaction txn = new Transaction(null, false);
+		Transaction txn = new Transaction(null, false);
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(false);
@@ -282,10 +280,10 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testSign() throws Exception {
-		final byte[] privateKey = getRandomBytes(42);
+		byte[] privateKey = getRandomBytes(42);
-		final byte[] signed = getRandomBytes(42);
+		byte[] signed = getRandomBytes(42);
 
-		final byte[] bytes = expectToByteArray(list);
+		byte[] bytes = expectToByteArray(list);
 		context.checking(new Expectations() {{
 			oneOf(cryptoComponent).sign(label, bytes, privateKey);
 			will(returnValue(signed));
@@ -297,8 +295,8 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testVerifySignature() throws Exception {
-		final byte[] publicKey = getRandomBytes(42);
+		byte[] publicKey = getRandomBytes(42);
-		final byte[] bytes = expectToByteArray(list);
+		byte[] bytes = expectToByteArray(list);
 
 		context.checking(new Expectations() {{
 			oneOf(cryptoComponent).verify(label, bytes, publicKey, rawMessage);
@@ -311,8 +309,8 @@ public class ClientHelperImplTest extends BrambleTestCase {
 
 	@Test
 	public void testVerifyWrongSignature() throws Exception {
-		final byte[] publicKey = getRandomBytes(42);
+		byte[] publicKey = getRandomBytes(42);
-		final byte[] bytes = expectToByteArray(list);
+		byte[] bytes = expectToByteArray(list);
 
 		context.checking(new Expectations() {{
 			oneOf(cryptoComponent).verify(label, bytes, publicKey, rawMessage);
@@ -329,8 +327,8 @@ public class ClientHelperImplTest extends BrambleTestCase {
 		}
 	}
 
-	private byte[] expectToByteArray(final BdfList list) throws Exception {
+	private byte[] expectToByteArray(BdfList list) throws Exception {
-		final BdfWriter bdfWriter = context.mock(BdfWriter.class);
+		BdfWriter bdfWriter = context.mock(BdfWriter.class);
 
 		context.checking(new Expectations() {{
 			oneOf(bdfWriterFactory)
@@ -341,8 +339,8 @@ public class ClientHelperImplTest extends BrambleTestCase {
 		return new byte[0];
 	}
 
-	private void expectToList(final boolean eof) throws Exception {
+	private void expectToList(boolean eof) throws Exception {
-		final BdfReader bdfReader = context.mock(BdfReader.class);
+		BdfReader bdfReader = context.mock(BdfReader.class);
 
 		context.checking(new Expectations() {{
 			oneOf(bdfReaderFactory)

bramble-core/src/test/java/org/briarproject/bramble/contact/ContactManagerImplTest.java

@@ -46,10 +46,10 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 
 	@Test
 	public void testAddContact() throws Exception {
-		final SecretKey master = getSecretKey();
+		SecretKey master = getSecretKey();
-		final long timestamp = 42;
+		long timestamp = 42;
-		final boolean alice = true;
+		boolean alice = true;
-		final Transaction txn = new Transaction(null, false);
+		Transaction txn = new Transaction(null, false);
 
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(false);
@@ -64,14 +64,13 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 			oneOf(db).endTransaction(txn);
 		}});
 
-		assertEquals(contactId, contactManager
+		assertEquals(contactId, contactManager.addContact(remote, local,
-				.addContact(remote, local, master, timestamp, alice, verified,
+				master, timestamp, alice, verified, active));
-						active));
 	}
 
 	@Test
 	public void testGetContact() throws Exception {
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
 			will(returnValue(txn));
@@ -86,8 +85,8 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 
 	@Test
 	public void testGetContactByAuthor() throws Exception {
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
-		final Collection<Contact> contacts = Collections.singleton(contact);
+		Collection<Contact> contacts = Collections.singleton(contact);
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
 			will(returnValue(txn));
@@ -102,7 +101,7 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 
 	@Test(expected = NoSuchContactException.class)
 	public void testGetContactByUnknownAuthor() throws Exception {
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
 			will(returnValue(txn));
@@ -116,8 +115,8 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 
 	@Test(expected = NoSuchContactException.class)
 	public void testGetContactByUnknownLocalAuthor() throws Exception {
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
-		final Collection<Contact> contacts = Collections.singleton(contact);
+		Collection<Contact> contacts = Collections.singleton(contact);
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
 			will(returnValue(txn));
@@ -132,10 +131,9 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	@Test
 	public void testActiveContacts() throws Exception {
 		Collection<Contact> activeContacts = Collections.singletonList(contact);
-		final Collection<Contact> contacts =
+		Collection<Contact> contacts = new ArrayList<>(activeContacts);
-				new ArrayList<Contact>(activeContacts);
 		contacts.add(new Contact(new ContactId(3), remote, local, true, false));
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
 			will(returnValue(txn));
@@ -150,7 +148,7 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 
 	@Test
 	public void testRemoveContact() throws Exception {
-		final Transaction txn = new Transaction(null, false);
+		Transaction txn = new Transaction(null, false);
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(false);
 			will(returnValue(txn));
@@ -166,7 +164,7 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 
 	@Test
 	public void testSetContactActive() throws Exception {
-		final Transaction txn = new Transaction(null, false);
+		Transaction txn = new Transaction(null, false);
 		context.checking(new Expectations() {{
 			oneOf(db).setContactActive(txn, contactId, active);
 		}});
@@ -176,7 +174,7 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 
 	@Test
 	public void testContactExists() throws Exception {
-		final Transaction txn = new Transaction(null, true);
+		Transaction txn = new Transaction(null, true);
 		context.checking(new Expectations() {{
 			oneOf(db).startTransaction(true);
 			will(returnValue(txn));

bramble-core/src/test/java/org/briarproject/bramble/crypto/EcdsaSignatureTest.java

@@ -0,0 +1,25 @@
+package org.briarproject.bramble.crypto;
+
+import org.briarproject.bramble.api.crypto.KeyPair;
+
+import java.security.GeneralSecurityException;
+
+public class EcdsaSignatureTest extends SignatureTest {
+
+	@Override
+	protected KeyPair generateKeyPair() {
+		return crypto.generateSignatureKeyPair();
+	}
+
+	@Override
+	protected byte[] sign(String label, byte[] toSign, byte[] privateKey)
+			throws GeneralSecurityException {
+		return crypto.sign(label, toSign, privateKey);
+	}
+
+	@Override
+	protected boolean verify(String label, byte[] signedData, byte[] publicKey,
+			byte[] signature) throws GeneralSecurityException {
+		return crypto.verify(label, signedData, publicKey, signature);
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/crypto/EdSignatureTest.java

@@ -0,0 +1,25 @@
+package org.briarproject.bramble.crypto;
+
+import org.briarproject.bramble.api.crypto.KeyPair;
+
+import java.security.GeneralSecurityException;
+
+public class EdSignatureTest extends SignatureTest {
+
+	@Override
+	protected KeyPair generateKeyPair() {
+		return crypto.generateEdKeyPair();
+	}
+
+	@Override
+	protected byte[] sign(String label, byte[] toSign, byte[] privateKey)
+			throws GeneralSecurityException {
+		return crypto.signEd(label, toSign, privateKey);
+	}
+
+	@Override
+	protected boolean verify(String label, byte[] signedData, byte[] publicKey,
+			byte[] signature) throws GeneralSecurityException {
+		return crypto.verifyEd(label, signedData, publicKey, signature);
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/crypto/EllipticCurvePerformanceTest.java

@@ -1,16 +1,19 @@
 package org.briarproject.bramble.crypto;
 
+import net.i2p.crypto.eddsa.EdDSASecurityProvider;
+import net.i2p.crypto.eddsa.KeyPairGenerator;
+
 import org.spongycastle.asn1.sec.SECNamedCurves;
 import org.spongycastle.asn1.teletrust.TeleTrusTNamedCurves;
 import org.spongycastle.asn1.x9.X9ECParameters;
 import org.spongycastle.crypto.AsymmetricCipherKeyPair;
+import org.spongycastle.crypto.BasicAgreement;
 import org.spongycastle.crypto.Digest;
+import org.spongycastle.crypto.agreement.ECDHBasicAgreement;
 import org.spongycastle.crypto.agreement.ECDHCBasicAgreement;
 import org.spongycastle.crypto.generators.ECKeyPairGenerator;
 import org.spongycastle.crypto.params.ECDomainParameters;
 import org.spongycastle.crypto.params.ECKeyGenerationParameters;
-import org.spongycastle.crypto.params.ECPrivateKeyParameters;
-import org.spongycastle.crypto.params.ECPublicKeyParameters;
 import org.spongycastle.crypto.params.ParametersWithRandom;
 import org.spongycastle.crypto.signers.DSADigestSigner;
 import org.spongycastle.crypto.signers.DSAKCalculator;
@@ -19,14 +22,23 @@ import org.spongycastle.crypto.signers.HMacDSAKCalculator;
 import org.spongycastle.math.ec.ECCurve;
 import org.spongycastle.math.ec.ECPoint;
 import org.spongycastle.math.ec.MontgomeryLadderMultiplier;
+import org.whispersystems.curve25519.Curve25519;
+import org.whispersystems.curve25519.Curve25519KeyPair;
 
 import java.math.BigInteger;
+import java.security.GeneralSecurityException;
+import java.security.KeyPair;
+import java.security.Provider;
 import java.security.SecureRandom;
+import java.security.Signature;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
+import static net.i2p.crypto.eddsa.EdDSAEngine.SIGNATURE_ALGORITHM;
+import static org.briarproject.bramble.crypto.EllipticCurveConstants.PARAMETERS;
+
 // Not a JUnit test
 public class EllipticCurvePerformanceTest {
 
@@ -37,8 +49,9 @@ public class EllipticCurvePerformanceTest {
 			"secp256k1", "secp256r1", "secp384r1", "secp521r1");
 	private static final List<String> BRAINPOOL_NAMES = Arrays.asList(
 			"brainpoolp256r1", "brainpoolp384r1", "brainpoolp512r1");
+	private static final Provider ED_PROVIDER = new EdDSASecurityProvider();
 
-	public static void main(String[] args) {
+	public static void main(String[] args) throws GeneralSecurityException {
 		for (String name : SEC_NAMES) {
 			ECDomainParameters params =
 					convertParams(SECNamedCurves.getByName(name));
@@ -51,43 +64,32 @@ public class EllipticCurvePerformanceTest {
 			runTest(name + " default", params);
 			runTest(name + " constant", constantTime(params));
 		}
-		runTest("ours", EllipticCurveConstants.PARAMETERS);
+		runTest("ours", PARAMETERS);
+		runCurve25519Test();
+		runEd25519Test();
 	}
 
 	private static void runTest(String name, ECDomainParameters params) {
 		// Generate two key pairs using the given parameters
-		ECKeyGenerationParameters generatorParams =
-				new ECKeyGenerationParameters(params, random);
 		ECKeyPairGenerator generator = new ECKeyPairGenerator();
-		generator.init(generatorParams);
+		generator.init(new ECKeyGenerationParameters(params, random));
 		AsymmetricCipherKeyPair keyPair1 = generator.generateKeyPair();
-		ECPublicKeyParameters public1 =
-				(ECPublicKeyParameters) keyPair1.getPublic();
-		ECPrivateKeyParameters private1 =
-				(ECPrivateKeyParameters) keyPair1.getPrivate();
 		AsymmetricCipherKeyPair keyPair2 = generator.generateKeyPair();
-		ECPublicKeyParameters public2 =
+		// Time some ECDH and ECDHC key agreements
-				(ECPublicKeyParameters) keyPair2.getPublic();
+		long agreementMedian = runAgreementTest(keyPair1, keyPair2, false);
-		// Time some ECDH key agreements
+		long agreementWithCofactorMedian =
-		List<Long> samples = new ArrayList<Long>();
+				runAgreementTest(keyPair1, keyPair2, true);
-		for (int i = 0; i < SAMPLES; i++) {
-			ECDHCBasicAgreement agreement = new ECDHCBasicAgreement();
-			long start = System.nanoTime();
-			agreement.init(private1);
-			agreement.calculateAgreement(public2);
-			samples.add(System.nanoTime() - start);
-		}
-		long agreementMedian = median(samples);
 		// Time some signatures
-		List<byte[]> signatures = new ArrayList<byte[]>();
+		List<Long> samples = new ArrayList<>();
-		samples.clear();
+		List<byte[]> signatures = new ArrayList<>();
 		for (int i = 0; i < SAMPLES; i++) {
 			Digest digest = new Blake2sDigest();
 			DSAKCalculator calculator = new HMacDSAKCalculator(digest);
 			DSADigestSigner signer = new DSADigestSigner(new ECDSASigner(
 					calculator), digest);
 			long start = System.nanoTime();
-			signer.init(true, new ParametersWithRandom(private1, random));
+			signer.init(true,
+					new ParametersWithRandom(keyPair1.getPrivate(), random));
 			signer.update(new byte[BYTES_TO_SIGN], 0, BYTES_TO_SIGN);
 			signatures.add(signer.generateSignature());
 			samples.add(System.nanoTime() - start);
@@ -101,17 +103,83 @@ public class EllipticCurvePerformanceTest {
 			DSADigestSigner signer = new DSADigestSigner(new ECDSASigner(
 					calculator), digest);
 			long start = System.nanoTime();
-			signer.init(false, public1);
+			signer.init(false, keyPair1.getPublic());
 			signer.update(new byte[BYTES_TO_SIGN], 0, BYTES_TO_SIGN);
 			if (!signer.verifySignature(signatures.get(i)))
 				throw new AssertionError();
 			samples.add(System.nanoTime() - start);
 		}
 		long verificationMedian = median(samples);
-		System.out.println(name + ": "
+		System.out.println(String.format("%s: %,d %,d %,d %,d", name,
-				+ agreementMedian + " "
+				agreementMedian, agreementWithCofactorMedian,
-				+ signatureMedian + " "
+				signatureMedian, verificationMedian));
-				+ verificationMedian);
+	}
+
+	private static long runAgreementTest(AsymmetricCipherKeyPair keyPair1,
+			AsymmetricCipherKeyPair keyPair2, boolean withCofactor) {
+		List<Long> samples = new ArrayList<>();
+		for (int i = 0; i < SAMPLES; i++) {
+			BasicAgreement agreement = createAgreement(withCofactor);
+			long start = System.nanoTime();
+			agreement.init(keyPair1.getPrivate());
+			agreement.calculateAgreement(keyPair2.getPublic());
+			samples.add(System.nanoTime() - start);
+		}
+		return median(samples);
+	}
+
+	private static BasicAgreement createAgreement(boolean withCofactor) {
+		if (withCofactor) return new ECDHCBasicAgreement();
+		else return new ECDHBasicAgreement();
+	}
+
+	private static void runCurve25519Test() {
+		Curve25519 curve25519 = Curve25519.getInstance("java");
+		Curve25519KeyPair keyPair1 = curve25519.generateKeyPair();
+		Curve25519KeyPair keyPair2 = curve25519.generateKeyPair();
+		// Time some key agreements
+		List<Long> samples = new ArrayList<>();
+		for (int i = 0; i < SAMPLES; i++) {
+			long start = System.nanoTime();
+			curve25519.calculateAgreement(keyPair1.getPublicKey(),
+					keyPair2.getPrivateKey());
+			samples.add(System.nanoTime() - start);
+		}
+		long agreementMedian = median(samples);
+		System.out.println(String.format("Curve25519: %,d - - -",
+				agreementMedian));
+	}
+
+	private static void runEd25519Test() throws GeneralSecurityException {
+		KeyPair keyPair = new KeyPairGenerator().generateKeyPair();
+		// Time some signatures
+		List<Long> samples = new ArrayList<>();
+		List<byte[]> signatures = new ArrayList<>();
+		for (int i = 0; i < SAMPLES; i++) {
+			Signature signature =
+					Signature.getInstance(SIGNATURE_ALGORITHM, ED_PROVIDER);
+			long start = System.nanoTime();
+			signature.initSign(keyPair.getPrivate(), random);
+			signature.update(new byte[BYTES_TO_SIGN], 0, BYTES_TO_SIGN);
+			signatures.add(signature.sign());
+			samples.add(System.nanoTime() - start);
+		}
+		long signatureMedian = median(samples);
+		// Time some signature verifications
+		samples.clear();
+		for (int i = 0; i < SAMPLES; i++) {
+			Signature signature =
+					Signature.getInstance(SIGNATURE_ALGORITHM, ED_PROVIDER);
+			long start = System.nanoTime();
+			signature.initVerify(keyPair.getPublic());
+			signature.update(new byte[BYTES_TO_SIGN], 0, BYTES_TO_SIGN);
+			if (!signature.verify(signatures.get(i)))
+				throw new AssertionError();
+			samples.add(System.nanoTime() - start);
+		}
+		long verificationMedian = median(samples);
+		System.out.println(String.format("Ed25519: - - %,d %,d",
+				signatureMedian, verificationMedian));
 	}
 
 	private static long median(List<Long> list) {

bramble-core/src/test/java/org/briarproject/bramble/crypto/KeyAgreementTest.java

@@ -3,40 +3,32 @@ package org.briarproject.bramble.crypto;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.KeyPair;
 import org.briarproject.bramble.api.crypto.SecretKey;
-import org.briarproject.bramble.api.system.SecureRandomProvider;
 import org.briarproject.bramble.test.BrambleTestCase;
 import org.briarproject.bramble.test.TestSecureRandomProvider;
 import org.junit.Test;
 
+import java.util.Random;
+
+import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.SHARED_SECRET_LABEL;
+import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
 import static org.junit.Assert.assertArrayEquals;
 
 public class KeyAgreementTest extends BrambleTestCase {
 
-	@Test
-	public void testDeriveMasterSecret() throws Exception {
-		SecureRandomProvider
-				secureRandomProvider = new TestSecureRandomProvider();
-		CryptoComponent crypto = new CryptoComponentImpl(secureRandomProvider);
-		KeyPair aPair = crypto.generateAgreementKeyPair();
-		byte[] aPub = aPair.getPublic().getEncoded();
-		KeyPair bPair = crypto.generateAgreementKeyPair();
-		byte[] bPub = bPair.getPublic().getEncoded();
-		SecretKey aMaster = crypto.deriveMasterSecret(aPub, bPair, true);
-		SecretKey bMaster = crypto.deriveMasterSecret(bPub, aPair, false);
-		assertArrayEquals(aMaster.getBytes(), bMaster.getBytes());
-	}
-
 	@Test
 	public void testDeriveSharedSecret() throws Exception {
-		SecureRandomProvider
+		CryptoComponent crypto =
-				secureRandomProvider = new TestSecureRandomProvider();
+				new CryptoComponentImpl(new TestSecureRandomProvider());
-		CryptoComponent crypto = new CryptoComponentImpl(secureRandomProvider);
 		KeyPair aPair = crypto.generateAgreementKeyPair();
-		byte[] aPub = aPair.getPublic().getEncoded();
 		KeyPair bPair = crypto.generateAgreementKeyPair();
-		byte[] bPub = bPair.getPublic().getEncoded();
+		Random random = new Random();
-		SecretKey aShared = crypto.deriveSharedSecret(bPub, aPair, true);
+		byte[][] inputs = new byte[random.nextInt(10) + 1][];
-		SecretKey bShared = crypto.deriveSharedSecret(aPub, bPair, false);
+		for (int i = 0; i < inputs.length; i++)
+			inputs[i] = getRandomBytes(random.nextInt(256));
+		SecretKey aShared = crypto.deriveSharedSecret(SHARED_SECRET_LABEL,
+				bPair.getPublic(), aPair, inputs);
+		SecretKey bShared = crypto.deriveSharedSecret(SHARED_SECRET_LABEL,
+				aPair.getPublic(), bPair, inputs);
 		assertArrayEquals(aShared.getBytes(), bShared.getBytes());
 	}
 }

bramble-core/src/test/java/org/briarproject/bramble/crypto/KeyDerivationTest.java

@@ -3,11 +3,11 @@ package org.briarproject.bramble.crypto;
 import org.briarproject.bramble.api.Bytes;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.crypto.TransportCrypto;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.transport.TransportKeys;
 import org.briarproject.bramble.test.BrambleTestCase;
 import org.briarproject.bramble.test.TestSecureRandomProvider;
-import org.briarproject.bramble.test.TestUtils;
 import org.junit.Test;
 
 import java.util.ArrayList;
@@ -16,35 +16,34 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
+import static org.briarproject.bramble.test.TestUtils.getSecretKey;
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 public class KeyDerivationTest extends BrambleTestCase {
 
+	private final CryptoComponent crypto =
+			new CryptoComponentImpl(new TestSecureRandomProvider());
+	private final TransportCrypto transportCrypto =
+			new TransportCryptoImpl(crypto);
 	private final TransportId transportId = new TransportId("id");
-	private final CryptoComponent crypto;
+	private final SecretKey master = getSecretKey();
-	private final SecretKey master;
-
-	public KeyDerivationTest() {
-		crypto = new CryptoComponentImpl(new TestSecureRandomProvider());
-		master = TestUtils.getSecretKey();
-	}
 
 	@Test
 	public void testKeysAreDistinct() {
-		TransportKeys k = crypto.deriveTransportKeys(transportId, master,
+		TransportKeys k = transportCrypto.deriveTransportKeys(transportId,
-				123, true);
+				master, 123, true);
 		assertAllDifferent(k);
 	}
 
 	@Test
 	public void testCurrentKeysMatchCurrentKeysOfContact() {
 		// Start in rotation period 123
-		TransportKeys kA = crypto.deriveTransportKeys(transportId, master,
+		TransportKeys kA = transportCrypto.deriveTransportKeys(transportId,
-				123, true);
+				master, 123, true);
-		TransportKeys kB = crypto.deriveTransportKeys(transportId, master,
+		TransportKeys kB = transportCrypto.deriveTransportKeys(transportId,
-				123, false);
+				master, 123, false);
 		// Alice's incoming keys should equal Bob's outgoing keys
 		assertArrayEquals(kA.getCurrentIncomingKeys().getTagKey().getBytes(),
 				kB.getCurrentOutgoingKeys().getTagKey().getBytes());
@@ -56,8 +55,8 @@ public class KeyDerivationTest extends BrambleTestCase {
 		assertArrayEquals(kA.getCurrentOutgoingKeys().getHeaderKey().getBytes(),
 				kB.getCurrentIncomingKeys().getHeaderKey().getBytes());
 		// Rotate into the future
-		kA = crypto.rotateTransportKeys(kA, 456);
+		kA = transportCrypto.rotateTransportKeys(kA, 456);
-		kB = crypto.rotateTransportKeys(kB, 456);
+		kB = transportCrypto.rotateTransportKeys(kB, 456);
 		// Alice's incoming keys should equal Bob's outgoing keys
 		assertArrayEquals(kA.getCurrentIncomingKeys().getTagKey().getBytes(),
 				kB.getCurrentOutgoingKeys().getTagKey().getBytes());
@@ -73,22 +72,23 @@ public class KeyDerivationTest extends BrambleTestCase {
 	@Test
 	public void testPreviousKeysMatchPreviousKeysOfContact() {
 		// Start in rotation period 123
-		TransportKeys kA = crypto.deriveTransportKeys(transportId, master,
+		TransportKeys kA = transportCrypto.deriveTransportKeys(transportId,
-				123, true);
+				master, 123, true);
-		TransportKeys kB = crypto.deriveTransportKeys(transportId, master,
+		TransportKeys kB = transportCrypto.deriveTransportKeys(transportId,
-				123, false);
+				master, 123, false);
 		// Compare Alice's previous keys in period 456 with Bob's current keys
 		// in period 455
-		kA = crypto.rotateTransportKeys(kA, 456);
+		kA = transportCrypto.rotateTransportKeys(kA, 456);
-		kB = crypto.rotateTransportKeys(kB, 455);
+		kB = transportCrypto.rotateTransportKeys(kB, 455);
 		// Alice's previous incoming keys should equal Bob's outgoing keys
 		assertArrayEquals(kA.getPreviousIncomingKeys().getTagKey().getBytes(),
 				kB.getCurrentOutgoingKeys().getTagKey().getBytes());
-		assertArrayEquals(kA.getPreviousIncomingKeys().getHeaderKey().getBytes(),
+		assertArrayEquals(
+				kA.getPreviousIncomingKeys().getHeaderKey().getBytes(),
 				kB.getCurrentOutgoingKeys().getHeaderKey().getBytes());
 		// Compare Alice's current keys in period 456 with Bob's previous keys
 		// in period 457
-		kB = crypto.rotateTransportKeys(kB, 457);
+		kB = transportCrypto.rotateTransportKeys(kB, 457);
 		// Alice's outgoing keys should equal Bob's previous incoming keys
 		assertArrayEquals(kA.getCurrentOutgoingKeys().getTagKey().getBytes(),
 				kB.getPreviousIncomingKeys().getTagKey().getBytes());
@@ -99,14 +99,14 @@ public class KeyDerivationTest extends BrambleTestCase {
 	@Test
 	public void testNextKeysMatchNextKeysOfContact() {
 		// Start in rotation period 123
-		TransportKeys kA = crypto.deriveTransportKeys(transportId, master,
+		TransportKeys kA = transportCrypto.deriveTransportKeys(transportId,
-				123, true);
+				master, 123, true);
-		TransportKeys kB = crypto.deriveTransportKeys(transportId, master,
+		TransportKeys kB = transportCrypto.deriveTransportKeys(transportId,
-				123, false);
+				master, 123, false);
 		// Compare Alice's current keys in period 456 with Bob's next keys in
 		// period 455
-		kA = crypto.rotateTransportKeys(kA, 456);
+		kA = transportCrypto.rotateTransportKeys(kA, 456);
-		kB = crypto.rotateTransportKeys(kB, 455);
+		kB = transportCrypto.rotateTransportKeys(kB, 455);
 		// Alice's outgoing keys should equal Bob's next incoming keys
 		assertArrayEquals(kA.getCurrentOutgoingKeys().getTagKey().getBytes(),
 				kB.getNextIncomingKeys().getTagKey().getBytes());
@@ -114,7 +114,7 @@ public class KeyDerivationTest extends BrambleTestCase {
 				kB.getNextIncomingKeys().getHeaderKey().getBytes());
 		// Compare Alice's next keys in period 456 with Bob's current keys
 		// in period 457
-		kB = crypto.rotateTransportKeys(kB, 457);
+		kB = transportCrypto.rotateTransportKeys(kB, 457);
 		// Alice's next incoming keys should equal Bob's outgoing keys
 		assertArrayEquals(kA.getNextIncomingKeys().getTagKey().getBytes(),
 				kB.getCurrentOutgoingKeys().getTagKey().getBytes());
@@ -124,12 +124,12 @@ public class KeyDerivationTest extends BrambleTestCase {
 
 	@Test
 	public void testMasterKeyAffectsOutput() {
-		SecretKey master1 = TestUtils.getSecretKey();
+		SecretKey master1 = getSecretKey();
 		assertFalse(Arrays.equals(master.getBytes(), master1.getBytes()));
-		TransportKeys k = crypto.deriveTransportKeys(transportId, master,
+		TransportKeys k = transportCrypto.deriveTransportKeys(transportId,
-				123, true);
+				master, 123, true);
-		TransportKeys k1 = crypto.deriveTransportKeys(transportId, master1,
+		TransportKeys k1 = transportCrypto.deriveTransportKeys(transportId,
-				123, true);
+				master1, 123, true);
 		assertAllDifferent(k, k1);
 	}
 
@@ -137,15 +137,15 @@ public class KeyDerivationTest extends BrambleTestCase {
 	public void testTransportIdAffectsOutput() {
 		TransportId transportId1 = new TransportId("id1");
 		assertFalse(transportId.getString().equals(transportId1.getString()));
-		TransportKeys k = crypto.deriveTransportKeys(transportId, master,
+		TransportKeys k = transportCrypto.deriveTransportKeys(transportId,
-				123, true);
+				master, 123, true);
-		TransportKeys k1 = crypto.deriveTransportKeys(transportId1, master,
+		TransportKeys k1 = transportCrypto.deriveTransportKeys(transportId1,
-				123, true);
+				master, 123, true);
 		assertAllDifferent(k, k1);
 	}
 
 	private void assertAllDifferent(TransportKeys... transportKeys) {
-		List<SecretKey> secretKeys = new ArrayList<SecretKey>();
+		List<SecretKey> secretKeys = new ArrayList<>();
 		for (TransportKeys k : transportKeys) {
 			secretKeys.add(k.getPreviousIncomingKeys().getTagKey());
 			secretKeys.add(k.getPreviousIncomingKeys().getHeaderKey());
@@ -160,7 +160,7 @@ public class KeyDerivationTest extends BrambleTestCase {
 	}
 
 	private void assertAllDifferent(List<SecretKey> keys) {
-		Set<Bytes> set = new HashSet<Bytes>();
+		Set<Bytes> set = new HashSet<>();
 		for (SecretKey k : keys) assertTrue(set.add(new Bytes(k.getBytes())));
 	}
 }

bramble-core/src/test/java/org/briarproject/bramble/crypto/MacTest.java

@@ -4,42 +4,49 @@ import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.test.BrambleTestCase;
 import org.briarproject.bramble.test.TestSecureRandomProvider;
-import org.briarproject.bramble.test.TestUtils;
 import org.junit.Test;
 
 import java.util.Arrays;
 
+import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
+import static org.briarproject.bramble.test.TestUtils.getSecretKey;
+import static org.briarproject.bramble.util.StringUtils.getRandomString;
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertFalse;
 
 public class MacTest extends BrambleTestCase {
 
-	private final CryptoComponent crypto;
+	private final CryptoComponent crypto =
+			new CryptoComponentImpl(new TestSecureRandomProvider());
 
-	private final SecretKey k = TestUtils.getSecretKey();
+	private final SecretKey key1 = getSecretKey(), key2 = getSecretKey();
-	private final byte[] inputBytes = TestUtils.getRandomBytes(123);
+	private final String label1 = getRandomString(123);
-	private final byte[] inputBytes1 = TestUtils.getRandomBytes(234);
+	private final String label2 = getRandomString(123);
-	private final byte[] inputBytes2 = new byte[0];
+	private final byte[] input1 = getRandomBytes(123);
-
+	private final byte[] input2 = getRandomBytes(234);
-	public MacTest() {
+	private final byte[] input3 = new byte[0];
-		crypto = new CryptoComponentImpl(new TestSecureRandomProvider());
-	}
 
 	@Test
 	public void testIdenticalKeysAndInputsProduceIdenticalMacs() {
 		// Calculate the MAC twice - the results should be identical
-		byte[] mac = crypto.mac(k, inputBytes, inputBytes1, inputBytes2);
+		byte[] mac = crypto.mac(label1, key1, input1, input2, input3);
-		byte[] mac1 = crypto.mac(k, inputBytes, inputBytes1, inputBytes2);
+		byte[] mac1 = crypto.mac(label1, key1, input1, input2, input3);
 		assertArrayEquals(mac, mac1);
 	}
 
+	@Test
+	public void testDifferentLabelsProduceDifferentMacs() {
+		// Calculate the MAC with each label - the results should be different
+		byte[] mac = crypto.mac(label1, key1, input1, input2, input3);
+		byte[] mac1 = crypto.mac(label2, key1, input1, input2, input3);
+		assertFalse(Arrays.equals(mac, mac1));
+	}
+
 	@Test
 	public void testDifferentKeysProduceDifferentMacs() {
-		// Generate second random key
-		SecretKey k1 = TestUtils.getSecretKey();
 		// Calculate the MAC with each key - the results should be different
-		byte[] mac = crypto.mac(k, inputBytes, inputBytes1, inputBytes2);
+		byte[] mac = crypto.mac(label1, key1, input1, input2, input3);
-		byte[] mac1 = crypto.mac(k1, inputBytes, inputBytes1, inputBytes2);
+		byte[] mac1 = crypto.mac(label1, key2, input1, input2, input3);
 		assertFalse(Arrays.equals(mac, mac1));
 	}
 
@@ -47,8 +54,8 @@ public class MacTest extends BrambleTestCase {
 	public void testDifferentInputsProduceDifferentMacs() {
 		// Calculate the MAC with the inputs in different orders - the results
 		// should be different
-		byte[] mac = crypto.mac(k, inputBytes, inputBytes1, inputBytes2);
+		byte[] mac = crypto.mac(label1, key1, input1, input2, input3);
-		byte[] mac1 = crypto.mac(k, inputBytes2, inputBytes1, inputBytes);
+		byte[] mac1 = crypto.mac(label1, key1, input3, input2, input1);
 		assertFalse(Arrays.equals(mac, mac1));
 	}