Bump version number for beta release.

(cherry picked from commit f0d8532)

.idea/runConfigurations/H2_Performance_Test.xml

@@ -1,23 +0,0 @@
-<component name="ProjectRunConfigurationManager">
-  <configuration default="false" name="H2 Performance Test" type="AndroidJUnit" factoryName="Android JUnit">
-    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
-    <module name="bramble-core" />
-    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
-    <option name="ALTERNATIVE_JRE_PATH" />
-    <option name="PACKAGE_NAME" value="org.briarproject.bramble.db" />
-    <option name="MAIN_CLASS_NAME" value="org.briarproject.bramble.db.H2DatabasePerformanceTest" />
-    <option name="METHOD_NAME" value="" />
-    <option name="TEST_OBJECT" value="class" />
-    <option name="VM_PARAMETERS" value="-ea" />
-    <option name="PARAMETERS" value="" />
-    <option name="WORKING_DIRECTORY" value="" />
-    <option name="ENV_VARIABLES" />
-    <option name="PASS_PARENT_ENVS" value="true" />
-    <option name="TEST_SEARCH_SCOPE">
-      <value defaultName="singleModule" />
-    </option>
-    <envs />
-    <patterns />
-    <method />
-  </configuration>
-</component>

.idea/runConfigurations/HyperSQL_Performance_Test.xml

@@ -1,23 +0,0 @@
-<component name="ProjectRunConfigurationManager">
-  <configuration default="false" name="HyperSQL Performance Test" type="AndroidJUnit" factoryName="Android JUnit">
-    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
-    <module name="bramble-core" />
-    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
-    <option name="ALTERNATIVE_JRE_PATH" />
-    <option name="PACKAGE_NAME" value="org.briarproject.bramble.db" />
-    <option name="MAIN_CLASS_NAME" value="org.briarproject.bramble.db.HyperSqlDatabasePerformanceTest" />
-    <option name="METHOD_NAME" value="" />
-    <option name="TEST_OBJECT" value="class" />
-    <option name="VM_PARAMETERS" value="-ea" />
-    <option name="PARAMETERS" value="" />
-    <option name="WORKING_DIRECTORY" value="" />
-    <option name="ENV_VARIABLES" />
-    <option name="PASS_PARENT_ENVS" value="true" />
-    <option name="TEST_SEARCH_SCOPE">
-      <value defaultName="singleModule" />
-    </option>
-    <envs />
-    <patterns />
-    <method />
-  </configuration>
-</component>

bramble-android/build.gradle

@@ -12,8 +12,8 @@ android {
 	defaultConfig {
 		minSdkVersion 14
 		targetSdkVersion 26
-		versionCode 1700
+		versionCode 1613
-		versionName "0.17.0"
+		versionName "0.16.13"
 		consumerProguardFiles 'proguard-rules.txt'
 	}
 
@@ -43,7 +43,6 @@ dependencyVerification {
 			'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',
@@ -55,16 +54,16 @@ dependencyVerification {
 }
 
 ext.torBinaryDir = 'src/main/res/raw'
-ext.torVersion = '0.2.9.14'
+ext.torVersion = '0.2.9.12'
-ext.geoipVersion = '2017-11-06'
+ext.geoipVersion = '2017-09-06'
 ext.torDownloadUrl = 'https://briarproject.org/build/'
 
 def torBinaries = [
-		"tor_arm"    : '1710ea6c47b7f4c1a88bdf4858c7893837635db10e8866854eed8d61629f50e8',
+		"tor_arm"    : '8ed0b347ffed1d6a4d2fd14495118eb92be83e9cc06e057e15220dc288b31688',
-		"tor_arm_pie": '974e6949507db8fa2ea45231817c2c3677ed4ccf5488a2252317d744b0be1917',
+		"tor_arm_pie": '64403262511c29f462ca5e7c7621bfc3c944898364d1d5ad35a016bb8a034283',
-		"tor_x86"    : '3a5e45b3f051fcda9353b098b7086e762ffe7ba9242f7d7c8bf6523faaa8b1e9',
+		"tor_x86"    : '61e014607a2079bcf1646289c67bff6372b1aded6e1d8d83d7791efda9a4d5ab',
-		"tor_x86_pie": 'd1d96d8ce1a4b68accf04850185780d10cd5563d3552f7e1f040f8ca32cb4e51',
+		"tor_x86_pie": '18fbc98356697dd0895836ab46d5c9877d1c539193464f7db1e82a65adaaf288',
-		"geoip"      : '8239b98374493529a29096e45fc5877d4d6fdad0146ad8380b291f90d61484ea'
+		"geoip"      : 'fe49d3adb86d3c512373101422a017dbb86c85a570524663f09dd8ce143a24f3'
 ]
 
 def downloadBinary(name) {

bramble-android/proguard-rules.txt

@@ -8,10 +8,6 @@
 -dontwarn dagger.**
 -dontnote dagger.**
 
--keep class net.i2p.crypto.eddsa.** { *; }
-
--keep class org.whispersystems.curve25519.** { *; }
-
 -dontwarn sun.misc.Unsafe
 -dontnote com.google.common.**
 

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

@@ -13,8 +13,7 @@ import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
 import org.briarproject.bramble.api.reporting.DevReporter;
 import org.briarproject.bramble.api.system.AndroidExecutor;
 import org.briarproject.bramble.api.system.LocationUtils;
-import org.briarproject.bramble.api.system.Scheduler;
+import org.briarproject.bramble.plugin.droidtooth.DroidtoothPluginFactory;
-import org.briarproject.bramble.plugin.bluetooth.AndroidBluetoothPluginFactory;
 import org.briarproject.bramble.plugin.tcp.AndroidLanTcpPluginFactory;
 import org.briarproject.bramble.plugin.tor.TorPluginFactory;
 
@@ -23,7 +22,6 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.concurrent.Executor;
-import java.util.concurrent.ScheduledExecutorService;
 
 import javax.net.SocketFactory;
 
@@ -35,18 +33,16 @@ public class AndroidPluginModule {
 
 	@Provides
 	PluginConfig providePluginConfig(@IoExecutor Executor ioExecutor,
-			@Scheduler ScheduledExecutorService scheduler,
 			AndroidExecutor androidExecutor, SecureRandom random,
 			SocketFactory torSocketFactory, BackoffFactory backoffFactory,
 			Application app, LocationUtils locationUtils, DevReporter reporter,
 			EventBus eventBus) {
 		Context appContext = app.getApplicationContext();
-		DuplexPluginFactory bluetooth =
+		DuplexPluginFactory bluetooth = new DroidtoothPluginFactory(ioExecutor,
-				new AndroidBluetoothPluginFactory(ioExecutor, androidExecutor,
+				androidExecutor, appContext, random, eventBus, backoffFactory);
-						appContext, random, eventBus, backoffFactory);
+		DuplexPluginFactory tor = new TorPluginFactory(ioExecutor, appContext,
-		DuplexPluginFactory tor = new TorPluginFactory(ioExecutor, scheduler,
+				locationUtils, reporter, eventBus, torSocketFactory,
-				appContext, locationUtils, reporter, eventBus,
+				backoffFactory);
-				torSocketFactory, backoffFactory);
 		DuplexPluginFactory lan = new AndroidLanTcpPluginFactory(ioExecutor,
 				backoffFactory, appContext);
 		Collection<DuplexPluginFactory> duplex =

bramble-android/src/main/java/org/briarproject/bramble/plugin/bluetooth/AndroidBluetoothPlugin.java

@@ -1,206 +0,0 @@
-package org.briarproject.bramble.plugin.bluetooth;
-
-import android.bluetooth.BluetoothAdapter;
-import android.bluetooth.BluetoothDevice;
-import android.bluetooth.BluetoothServerSocket;
-import android.bluetooth.BluetoothSocket;
-import android.content.BroadcastReceiver;
-import android.content.Context;
-import android.content.Intent;
-import android.content.IntentFilter;
-
-import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
-import org.briarproject.bramble.api.plugin.Backoff;
-import org.briarproject.bramble.api.plugin.PluginException;
-import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-import org.briarproject.bramble.api.system.AndroidExecutor;
-import org.briarproject.bramble.util.AndroidUtils;
-
-import java.io.Closeable;
-import java.io.IOException;
-import java.security.SecureRandom;
-import java.util.UUID;
-import java.util.concurrent.ExecutionException;
-import java.util.concurrent.Executor;
-import java.util.logging.Logger;
-
-import javax.annotation.Nullable;
-
-import static android.bluetooth.BluetoothAdapter.ACTION_SCAN_MODE_CHANGED;
-import static android.bluetooth.BluetoothAdapter.ACTION_STATE_CHANGED;
-import static android.bluetooth.BluetoothAdapter.EXTRA_SCAN_MODE;
-import static android.bluetooth.BluetoothAdapter.EXTRA_STATE;
-import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE;
-import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE;
-import static android.bluetooth.BluetoothAdapter.SCAN_MODE_NONE;
-import static android.bluetooth.BluetoothAdapter.STATE_OFF;
-import static android.bluetooth.BluetoothAdapter.STATE_ON;
-import static java.util.logging.Level.WARNING;
-
-@MethodsNotNullByDefault
-@ParametersNotNullByDefault
-class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
-
-	private static final Logger LOG =
-			Logger.getLogger(AndroidBluetoothPlugin.class.getName());
-
-	private final AndroidExecutor androidExecutor;
-	private final Context appContext;
-
-	private volatile boolean wasEnabledByUs = false;
-	private volatile BluetoothStateReceiver receiver = null;
-
-	// Non-null if the plugin started successfully
-	private volatile BluetoothAdapter adapter = null;
-
-	AndroidBluetoothPlugin(Executor ioExecutor, AndroidExecutor androidExecutor,
-			Context appContext, SecureRandom secureRandom, Backoff backoff,
-			DuplexPluginCallback callback, int maxLatency) {
-		super(ioExecutor, secureRandom, backoff, callback, maxLatency);
-		this.androidExecutor = androidExecutor;
-		this.appContext = appContext;
-	}
-
-	@Override
-	public void start() throws PluginException {
-		super.start();
-		// Listen for changes to the Bluetooth state
-		IntentFilter filter = new IntentFilter();
-		filter.addAction(ACTION_STATE_CHANGED);
-		filter.addAction(ACTION_SCAN_MODE_CHANGED);
-		receiver = new BluetoothStateReceiver();
-		appContext.registerReceiver(receiver, filter);
-	}
-
-	@Override
-	public void stop() {
-		super.stop();
-		if (receiver != null) appContext.unregisterReceiver(receiver);
-	}
-
-	@Override
-	void initialiseAdapter() throws IOException {
-		// BluetoothAdapter.getDefaultAdapter() must be called on a thread
-		// with a message queue, so submit it to the AndroidExecutor
-		try {
-			adapter = androidExecutor.runOnBackgroundThread(
-					BluetoothAdapter::getDefaultAdapter).get();
-		} catch (InterruptedException | ExecutionException e) {
-			throw new IOException(e);
-		}
-		if (adapter == null)
-			throw new IOException("Bluetooth is not supported");
-	}
-
-	@Override
-	boolean isAdapterEnabled() {
-		return adapter != null && adapter.isEnabled();
-	}
-
-	@Override
-	void enableAdapter() {
-		if (adapter != null && !adapter.isEnabled()) {
-			if (adapter.enable()) {
-				LOG.info("Enabling Bluetooth");
-				wasEnabledByUs = true;
-			} else {
-				LOG.info("Could not enable Bluetooth");
-			}
-		}
-	}
-
-	@Override
-	void disableAdapterIfEnabledByUs() {
-		if (isAdapterEnabled() && wasEnabledByUs) {
-			if (adapter.disable()) LOG.info("Disabling Bluetooth");
-			else LOG.info("Could not disable Bluetooth");
-			wasEnabledByUs = false;
-		}
-	}
-
-	@Override
-	void setEnabledByUs() {
-		wasEnabledByUs = true;
-	}
-
-	@Override
-	@Nullable
-	String getBluetoothAddress() {
-		String address = AndroidUtils.getBluetoothAddress(appContext, adapter);
-		return address.isEmpty() ? null : address;
-	}
-
-	@Override
-	BluetoothServerSocket openServerSocket(String uuid) throws IOException {
-		return adapter.listenUsingInsecureRfcommWithServiceRecord(
-				"RFCOMM", UUID.fromString(uuid));
-	}
-
-	@Override
-	void tryToClose(@Nullable BluetoothServerSocket ss) {
-		try {
-			if (ss != null) ss.close();
-		} catch (IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		}
-	}
-
-	@Override
-	DuplexTransportConnection acceptConnection(BluetoothServerSocket ss)
-			throws IOException {
-		return wrapSocket(ss.accept());
-	}
-
-	private DuplexTransportConnection wrapSocket(BluetoothSocket s) {
-		return new AndroidBluetoothTransportConnection(this, s);
-	}
-
-	@Override
-	boolean isValidAddress(String address) {
-		return BluetoothAdapter.checkBluetoothAddress(address);
-	}
-
-	@Override
-	DuplexTransportConnection connectTo(String address, String uuid)
-			throws IOException {
-		BluetoothDevice d = adapter.getRemoteDevice(address);
-		UUID u = UUID.fromString(uuid);
-		BluetoothSocket s = null;
-		try {
-			s = d.createInsecureRfcommSocketToServiceRecord(u);
-			s.connect();
-			return wrapSocket(s);
-		} catch (IOException e) {
-			tryToClose(s);
-			throw e;
-		}
-	}
-
-	private void tryToClose(@Nullable Closeable c) {
-		try {
-			if (c != null) c.close();
-		} catch (IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		}
-	}
-
-	private class BluetoothStateReceiver extends BroadcastReceiver {
-
-		@Override
-		public void onReceive(Context ctx, Intent intent) {
-			int state = intent.getIntExtra(EXTRA_STATE, 0);
-			if (state == STATE_ON) onAdapterEnabled();
-			else if (state == STATE_OFF) onAdapterDisabled();
-			int scanMode = intent.getIntExtra(EXTRA_SCAN_MODE, 0);
-			if (scanMode == SCAN_MODE_NONE) {
-				LOG.info("Scan mode: None");
-			} else if (scanMode == SCAN_MODE_CONNECTABLE) {
-				LOG.info("Scan mode: Connectable");
-			} else if (scanMode == SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
-				LOG.info("Scan mode: Discoverable");
-			}
-		}
-	}
-}

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

@@ -0,0 +1,490 @@
+package org.briarproject.bramble.plugin.droidtooth;
+
+import android.bluetooth.BluetoothAdapter;
+import android.bluetooth.BluetoothDevice;
+import android.bluetooth.BluetoothServerSocket;
+import android.bluetooth.BluetoothSocket;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventListener;
+import org.briarproject.bramble.api.keyagreement.KeyAgreementConnection;
+import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.bramble.api.plugin.Backoff;
+import org.briarproject.bramble.api.plugin.PluginException;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
+import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.bramble.api.plugin.event.DisableBluetoothEvent;
+import org.briarproject.bramble.api.plugin.event.EnableBluetoothEvent;
+import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.bramble.util.AndroidUtils;
+import org.briarproject.bramble.util.StringUtils;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.security.SecureRandom;
+import java.util.Collection;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.UUID;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Executor;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+
+import static android.bluetooth.BluetoothAdapter.ACTION_SCAN_MODE_CHANGED;
+import static android.bluetooth.BluetoothAdapter.ACTION_STATE_CHANGED;
+import static android.bluetooth.BluetoothAdapter.EXTRA_SCAN_MODE;
+import static android.bluetooth.BluetoothAdapter.EXTRA_STATE;
+import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE;
+import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE;
+import static android.bluetooth.BluetoothAdapter.SCAN_MODE_NONE;
+import static android.bluetooth.BluetoothAdapter.STATE_OFF;
+import static android.bluetooth.BluetoothAdapter.STATE_ON;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
+import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.TRANSPORT_ID_BLUETOOTH;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.PREF_BT_ENABLE;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_ADDRESS;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_UUID;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.UUID_BYTES;
+import static org.briarproject.bramble.util.PrivacyUtils.scrubMacAddress;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+class DroidtoothPlugin implements DuplexPlugin, EventListener {
+
+	private static final Logger LOG =
+			Logger.getLogger(DroidtoothPlugin.class.getName());
+
+	private final Executor ioExecutor;
+	private final AndroidExecutor androidExecutor;
+	private final Context appContext;
+	private final SecureRandom secureRandom;
+	private final Backoff backoff;
+	private final DuplexPluginCallback callback;
+	private final int maxLatency;
+	private final AtomicBoolean used = new AtomicBoolean(false);
+
+	private volatile boolean running = false;
+	private volatile boolean wasEnabledByUs = false;
+	private volatile BluetoothStateReceiver receiver = null;
+	private volatile BluetoothServerSocket socket = null;
+
+	// Non-null if the plugin started successfully
+	private volatile BluetoothAdapter adapter = null;
+
+	DroidtoothPlugin(Executor ioExecutor, AndroidExecutor androidExecutor,
+			Context appContext, SecureRandom secureRandom, Backoff backoff,
+			DuplexPluginCallback callback, int maxLatency) {
+		this.ioExecutor = ioExecutor;
+		this.androidExecutor = androidExecutor;
+		this.appContext = appContext;
+		this.secureRandom = secureRandom;
+		this.backoff = backoff;
+		this.callback = callback;
+		this.maxLatency = maxLatency;
+	}
+
+	@Override
+	public TransportId getId() {
+		return ID;
+	}
+
+	@Override
+	public int getMaxLatency() {
+		return maxLatency;
+	}
+
+	@Override
+	public int getMaxIdleTime() {
+		// Bluetooth detects dead connections so we don't need keepalives
+		return Integer.MAX_VALUE;
+	}
+
+	@Override
+	public void start() throws PluginException {
+		if (used.getAndSet(true)) throw new IllegalStateException();
+		// BluetoothAdapter.getDefaultAdapter() must be called on a thread
+		// with a message queue, so submit it to the AndroidExecutor
+		try {
+			adapter = androidExecutor.runOnBackgroundThread(
+					BluetoothAdapter::getDefaultAdapter).get();
+		} catch (InterruptedException e) {
+			Thread.currentThread().interrupt();
+			LOG.warning("Interrupted while getting BluetoothAdapter");
+			throw new PluginException(e);
+		} catch (ExecutionException e) {
+			throw new PluginException(e);
+		}
+		if (adapter == null) {
+			LOG.info("Bluetooth is not supported");
+			throw new PluginException();
+		}
+		running = true;
+		// Listen for changes to the Bluetooth state
+		IntentFilter filter = new IntentFilter();
+		filter.addAction(ACTION_STATE_CHANGED);
+		filter.addAction(ACTION_SCAN_MODE_CHANGED);
+		receiver = new BluetoothStateReceiver();
+		appContext.registerReceiver(receiver, filter);
+		// If Bluetooth is enabled, bind a socket
+		if (adapter.isEnabled()) {
+			bind();
+		} else {
+			// Enable Bluetooth if settings allow
+			if (callback.getSettings().getBoolean(PREF_BT_ENABLE, false)) {
+				enableAdapter();
+			} else {
+				LOG.info("Not enabling Bluetooth");
+			}
+		}
+	}
+
+	private void bind() {
+		ioExecutor.execute(() -> {
+			if (!isRunning()) return;
+			String address = AndroidUtils.getBluetoothAddress(appContext,
+					adapter);
+			if (LOG.isLoggable(INFO))
+				LOG.info("Local address " + scrubMacAddress(address));
+			if (!StringUtils.isNullOrEmpty(address)) {
+				// Advertise the Bluetooth address to contacts
+				TransportProperties p = new TransportProperties();
+				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();
+		});
+	}
+
+	private UUID getUuid() {
+		String uuid = callback.getLocalProperties().get(PROP_UUID);
+		if (uuid == null) {
+			byte[] random = new byte[UUID_BYTES];
+			secureRandom.nextBytes(random);
+			uuid = UUID.nameUUIDFromBytes(random).toString();
+			TransportProperties p = new TransportProperties();
+			p.put(PROP_UUID, uuid);
+			callback.mergeLocalProperties(p);
+		}
+		return UUID.fromString(uuid);
+	}
+
+	private void tryToClose(@Nullable BluetoothServerSocket ss) {
+		try {
+			if (ss != null) ss.close();
+		} catch (IOException e) {
+			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+		} finally {
+			callback.transportDisabled();
+		}
+	}
+
+	private void acceptContactConnections() {
+		while (isRunning()) {
+			BluetoothSocket s;
+			try {
+				s = socket.accept();
+			} catch (IOException e) {
+				// This is expected when the socket is closed
+				if (LOG.isLoggable(INFO)) LOG.info(e.toString());
+				return;
+			}
+			if (LOG.isLoggable(INFO)) {
+				String address = s.getRemoteDevice().getAddress();
+				LOG.info("Connection from " + scrubMacAddress(address));
+			}
+			backoff.reset();
+			callback.incomingConnectionCreated(wrapSocket(s));
+		}
+	}
+
+	private DuplexTransportConnection wrapSocket(BluetoothSocket s) {
+		return new DroidtoothTransportConnection(this, s);
+	}
+
+	private void enableAdapter() {
+		if (adapter != null && !adapter.isEnabled()) {
+			if (adapter.enable()) {
+				LOG.info("Enabling Bluetooth");
+				wasEnabledByUs = true;
+			} else {
+				LOG.info("Could not enable Bluetooth");
+			}
+		}
+	}
+
+	@Override
+	public void stop() {
+		running = false;
+		if (receiver != null) appContext.unregisterReceiver(receiver);
+		tryToClose(socket);
+		disableAdapter();
+	}
+
+	private void disableAdapter() {
+		if (adapter != null && adapter.isEnabled() && wasEnabledByUs) {
+			if (adapter.disable()) LOG.info("Disabling Bluetooth");
+			else LOG.info("Could not disable Bluetooth");
+		}
+	}
+
+	@Override
+	public boolean isRunning() {
+		return running && adapter != null && adapter.isEnabled();
+	}
+
+	@Override
+	public boolean shouldPoll() {
+		return true;
+	}
+
+	@Override
+	public int getPollingInterval() {
+		return backoff.getPollingInterval();
+	}
+
+	@Override
+	public void poll(Collection<ContactId> connected) {
+		if (!isRunning()) return;
+		backoff.increment();
+		// Try to connect to known devices in parallel
+		Map<ContactId, TransportProperties> remote =
+				callback.getRemoteProperties();
+		for (Entry<ContactId, TransportProperties> e : remote.entrySet()) {
+			ContactId c = e.getKey();
+			if (connected.contains(c)) continue;
+			String address = e.getValue().get(PROP_ADDRESS);
+			if (StringUtils.isNullOrEmpty(address)) continue;
+			String uuid = e.getValue().get(PROP_UUID);
+			if (StringUtils.isNullOrEmpty(uuid)) continue;
+			ioExecutor.execute(() -> {
+				if (!running) return;
+				BluetoothSocket s = connect(address, uuid);
+				if (s != null) {
+					backoff.reset();
+					callback.outgoingConnectionCreated(c, wrapSocket(s));
+				}
+			});
+		}
+	}
+
+	@Nullable
+	private BluetoothSocket connect(String address, String uuid) {
+		// Validate the address
+		if (!BluetoothAdapter.checkBluetoothAddress(address)) {
+			if (LOG.isLoggable(WARNING))
+				// not scrubbing here to be able to figure out the problem
+				LOG.warning("Invalid address " + address);
+			return null;
+		}
+		// Validate the UUID
+		UUID u;
+		try {
+			u = UUID.fromString(uuid);
+		} catch (IllegalArgumentException e) {
+			if (LOG.isLoggable(WARNING)) LOG.warning("Invalid UUID " + uuid);
+			return null;
+		}
+		// Try to connect
+		BluetoothDevice d = adapter.getRemoteDevice(address);
+		BluetoothSocket s = null;
+		try {
+			s = d.createInsecureRfcommSocketToServiceRecord(u);
+			if (LOG.isLoggable(INFO))
+				LOG.info("Connecting to " + scrubMacAddress(address));
+			s.connect();
+			if (LOG.isLoggable(INFO))
+				LOG.info("Connected to " + scrubMacAddress(address));
+			return s;
+		} catch (IOException e) {
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Failed to connect to " + scrubMacAddress(address)
+						+ ": " + e);
+			}
+			tryToClose(s);
+			return null;
+		}
+	}
+
+	private void tryToClose(@Nullable Closeable c) {
+		try {
+			if (c != null) c.close();
+		} catch (IOException e) {
+			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+		}
+	}
+
+	@Override
+	public DuplexTransportConnection createConnection(ContactId c) {
+		if (!isRunning()) return null;
+		TransportProperties p = callback.getRemoteProperties(c);
+		String address = p.get(PROP_ADDRESS);
+		if (StringUtils.isNullOrEmpty(address)) return null;
+		String uuid = p.get(PROP_UUID);
+		if (StringUtils.isNullOrEmpty(uuid)) return null;
+		BluetoothSocket s = connect(address, uuid);
+		if (s == null) return null;
+		return new DroidtoothTransportConnection(this, s);
+	}
+
+	@Override
+	public boolean supportsKeyAgreement() {
+		return true;
+	}
+
+	@Override
+	public KeyAgreementListener createKeyAgreementListener(byte[] commitment) {
+		if (!isRunning()) return null;
+		// There's no point listening if we can't discover our own address
+		String address = AndroidUtils.getBluetoothAddress(appContext, adapter);
+		if (address.isEmpty()) return null;
+		// No truncation necessary because COMMIT_LENGTH = 16
+		UUID uuid = UUID.nameUUIDFromBytes(commitment);
+		if (LOG.isLoggable(INFO)) LOG.info("Key agreement UUID " + uuid);
+		// Bind a server socket for receiving key agreement connections
+		BluetoothServerSocket ss;
+		try {
+			ss = adapter.listenUsingInsecureRfcommWithServiceRecord(
+					"RFCOMM", uuid);
+		} catch (IOException e) {
+			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+			return null;
+		}
+		BdfList descriptor = new BdfList();
+		descriptor.add(TRANSPORT_ID_BLUETOOTH);
+		descriptor.add(StringUtils.macToBytes(address));
+		return new BluetoothKeyAgreementListener(descriptor, ss);
+	}
+
+	@Override
+	public DuplexTransportConnection createKeyAgreementConnection(
+			byte[] commitment, BdfList descriptor, long timeout) {
+		if (!isRunning()) return null;
+		String address;
+		try {
+			address = parseAddress(descriptor);
+		} catch (FormatException e) {
+			LOG.info("Invalid address in key agreement descriptor");
+			return null;
+		}
+		// No truncation necessary because COMMIT_LENGTH = 16
+		UUID uuid = UUID.nameUUIDFromBytes(commitment);
+		if (LOG.isLoggable(INFO))
+			LOG.info("Connecting to key agreement UUID " + uuid);
+		BluetoothSocket s = connect(address, uuid.toString());
+		if (s == null) return null;
+		return new DroidtoothTransportConnection(this, s);
+	}
+
+	private String parseAddress(BdfList descriptor) throws FormatException {
+		byte[] mac = descriptor.getRaw(1);
+		if (mac.length != 6) throw new FormatException();
+		return StringUtils.macToString(mac);
+	}
+
+	@Override
+	public void eventOccurred(Event e) {
+		if (e instanceof EnableBluetoothEvent) {
+			enableAdapterAsync();
+		} else if (e instanceof DisableBluetoothEvent) {
+			disableAdapterAsync();
+		}
+	}
+
+	private void enableAdapterAsync() {
+		ioExecutor.execute(this::enableAdapter);
+	}
+
+	private void disableAdapterAsync() {
+		ioExecutor.execute(this::disableAdapter);
+	}
+
+	private class BluetoothStateReceiver extends BroadcastReceiver {
+
+		@Override
+		public void onReceive(Context ctx, Intent intent) {
+			int state = intent.getIntExtra(EXTRA_STATE, 0);
+			if (state == STATE_ON) {
+				LOG.info("Bluetooth enabled");
+				bind();
+			} else if (state == STATE_OFF) {
+				LOG.info("Bluetooth disabled");
+				tryToClose(socket);
+			}
+			int scanMode = intent.getIntExtra(EXTRA_SCAN_MODE, 0);
+			if (scanMode == SCAN_MODE_NONE) {
+				LOG.info("Scan mode: None");
+			} else if (scanMode == SCAN_MODE_CONNECTABLE) {
+				LOG.info("Scan mode: Connectable");
+			} else if (scanMode == SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
+				LOG.info("Scan mode: Discoverable");
+			}
+		}
+	}
+
+	private class BluetoothKeyAgreementListener extends KeyAgreementListener {
+
+		private final BluetoothServerSocket ss;
+
+		private BluetoothKeyAgreementListener(BdfList descriptor,
+				BluetoothServerSocket ss) {
+			super(descriptor);
+			this.ss = ss;
+		}
+
+		@Override
+		public Callable<KeyAgreementConnection> listen() {
+			return () -> {
+				BluetoothSocket s = ss.accept();
+				if (LOG.isLoggable(INFO))
+					LOG.info(ID.getString() + ": Incoming connection");
+				return new KeyAgreementConnection(
+						new DroidtoothTransportConnection(
+								DroidtoothPlugin.this, s), ID);
+			};
+		}
+
+		@Override
+		public void close() {
+			try {
+				ss.close();
+			} catch (IOException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+			}
+		}
+	}
+}

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

@@ -1,4 +1,4 @@
-package org.briarproject.bramble.plugin.bluetooth;
+package org.briarproject.bramble.plugin.droidtooth;
 
 import android.content.Context;
 
@@ -21,7 +21,7 @@ import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
 
 @Immutable
 @NotNullByDefault
-public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
+public class DroidtoothPluginFactory implements DuplexPluginFactory {
 
 	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
 	private static final int MIN_POLLING_INTERVAL = 60 * 1000; // 1 minute
@@ -35,7 +35,7 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 	private final EventBus eventBus;
 	private final BackoffFactory backoffFactory;
 
-	public AndroidBluetoothPluginFactory(Executor ioExecutor,
+	public DroidtoothPluginFactory(Executor ioExecutor,
 			AndroidExecutor androidExecutor, Context appContext,
 			SecureRandom secureRandom, EventBus eventBus,
 			BackoffFactory backoffFactory) {
@@ -61,7 +61,7 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 	public DuplexPlugin createPlugin(DuplexPluginCallback callback) {
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		AndroidBluetoothPlugin plugin = new AndroidBluetoothPlugin(ioExecutor,
+		DroidtoothPlugin plugin = new DroidtoothPlugin(ioExecutor,
 				androidExecutor, appContext, secureRandom, backoff, callback,
 				MAX_LATENCY);
 		eventBus.addListener(plugin);

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

@@ -1,4 +1,4 @@
-package org.briarproject.bramble.plugin.bluetooth;
+package org.briarproject.bramble.plugin.droidtooth;
 
 import android.bluetooth.BluetoothSocket;
 
@@ -11,12 +11,11 @@ import java.io.InputStream;
 import java.io.OutputStream;
 
 @NotNullByDefault
-class AndroidBluetoothTransportConnection
+class DroidtoothTransportConnection extends AbstractDuplexTransportConnection {
-		extends AbstractDuplexTransportConnection {
 
 	private final BluetoothSocket socket;
 
-	AndroidBluetoothTransportConnection(Plugin plugin, BluetoothSocket socket) {
+	DroidtoothTransportConnection(Plugin plugin, BluetoothSocket socket) {
 		super(plugin);
 		this.socket = socket;
 	}

bramble-android/src/main/java/org/briarproject/bramble/plugin/tcp/AndroidLanTcpPlugin.java

@@ -6,7 +6,6 @@ import android.content.Intent;
 import android.content.IntentFilter;
 import android.net.ConnectivityManager;
 import android.net.NetworkInfo;
-import android.os.Bundle;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
@@ -20,15 +19,10 @@ import javax.annotation.Nullable;
 import static android.content.Context.CONNECTIVITY_SERVICE;
 import static android.net.ConnectivityManager.CONNECTIVITY_ACTION;
 import static android.net.ConnectivityManager.TYPE_WIFI;
-import static android.net.wifi.WifiManager.EXTRA_WIFI_STATE;
-import static java.util.logging.Level.INFO;
-import static org.briarproject.bramble.util.AndroidUtils.logNetworkState;
 
 @NotNullByDefault
 class AndroidLanTcpPlugin extends LanTcpPlugin {
 
-	private static final String WIFI_AP_STATE_ACTION =
-			"android.net.wifi.WIFI_AP_STATE_CHANGED";
 	private static final Logger LOG =
 			Logger.getLogger(AndroidLanTcpPlugin.class.getName());
 
@@ -50,11 +44,8 @@ class AndroidLanTcpPlugin extends LanTcpPlugin {
 		running = true;
 		// Register to receive network status events
 		networkStateReceiver = new NetworkStateReceiver();
-		IntentFilter filter = new IntentFilter();
+		IntentFilter filter = new IntentFilter(CONNECTIVITY_ACTION);
-		filter.addAction(CONNECTIVITY_ACTION);
-		filter.addAction(WIFI_AP_STATE_ACTION);
 		appContext.registerReceiver(networkStateReceiver, filter);
-		if (LOG.isLoggable(INFO)) logNetworkState(appContext, LOG);
 	}
 
 	@Override
@@ -70,27 +61,10 @@ class AndroidLanTcpPlugin extends LanTcpPlugin {
 		@Override
 		public void onReceive(Context ctx, Intent i) {
 			if (!running) return;
-			if (LOG.isLoggable(INFO)) {
-				if (CONNECTIVITY_ACTION.equals(i.getAction())) {
-					LOG.info("Connectivity change");
-					Bundle extras = i.getExtras();
-					if (extras != null) {
-						LOG.info("Extras:");
-						for (String key : extras.keySet())
-							LOG.info("\t" + key + ": " + extras.get(key));
-					}
-				} else if (WIFI_AP_STATE_ACTION.equals(i.getAction())) {
-					int state = i.getIntExtra(EXTRA_WIFI_STATE, 0);
-					if (state == 13) LOG.info("Wifi AP enabled");
-					else LOG.info("Wifi AP state " + state);
-				}
-				logNetworkState(appContext, LOG);
-			}
 			Object o = ctx.getSystemService(CONNECTIVITY_SERVICE);
 			ConnectivityManager cm = (ConnectivityManager) o;
 			NetworkInfo net = cm.getActiveNetworkInfo();
-			if (net != null && net.getType() == TYPE_WIFI
+			if (net != null && net.getType() == TYPE_WIFI && net.isConnected()) {
-					&& net.isConnected()) {
 				LOG.info("Connected to Wi-Fi");
 				if (socket == null || socket.isClosed()) bind();
 			} else {

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

@@ -59,12 +59,7 @@ import java.util.Map.Entry;
 import java.util.Scanner;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Executor;
-import java.util.concurrent.Future;
-import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicReference;
-import java.util.concurrent.locks.Lock;
-import java.util.concurrent.locks.ReentrantLock;
 import java.util.logging.Logger;
 import java.util.regex.Pattern;
 import java.util.zip.ZipInputStream;
@@ -75,15 +70,10 @@ import javax.net.SocketFactory;
 import static android.content.Context.CONNECTIVITY_SERVICE;
 import static android.content.Context.MODE_PRIVATE;
 import static android.content.Context.POWER_SERVICE;
-import static android.content.Intent.ACTION_SCREEN_OFF;
-import static android.content.Intent.ACTION_SCREEN_ON;
 import static android.net.ConnectivityManager.CONNECTIVITY_ACTION;
 import static android.net.ConnectivityManager.TYPE_WIFI;
-import static android.os.Build.VERSION.SDK_INT;
-import static android.os.PowerManager.ACTION_DEVICE_IDLE_MODE_CHANGED;
 import static android.os.PowerManager.PARTIAL_WAKE_LOCK;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
-import static java.util.concurrent.TimeUnit.MINUTES;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static net.freehaven.tor.control.TorControlCommands.HS_ADDRESS;
@@ -112,7 +102,6 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			Logger.getLogger(TorPlugin.class.getName());
 
 	private final Executor ioExecutor;
-	private final ScheduledExecutorService scheduler;
 	private final Context appContext;
 	private final LocationUtils locationUtils;
 	private final DevReporter reporter;
@@ -125,9 +114,6 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private final File torDirectory, torFile, geoIpFile, configFile;
 	private final File doneFile, cookieFile;
 	private final PowerManager.WakeLock wakeLock;
-	private final Lock connectionStatusLock;
-	private final AtomicReference<Future<?>> connectivityCheck =
-			new AtomicReference<>();
 	private final AtomicBoolean used = new AtomicBoolean(false);
 
 	private volatile boolean running = false;
@@ -136,13 +122,12 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private volatile TorControlConnection controlConnection = null;
 	private volatile BroadcastReceiver networkStateReceiver = null;
 
-	TorPlugin(Executor ioExecutor, ScheduledExecutorService scheduler,
+	TorPlugin(Executor ioExecutor, Context appContext,
-			Context appContext, LocationUtils locationUtils,
+			LocationUtils locationUtils, DevReporter reporter,
-			DevReporter reporter, SocketFactory torSocketFactory,
+			SocketFactory torSocketFactory, Backoff backoff,
-			Backoff backoff, DuplexPluginCallback callback,
+			DuplexPluginCallback callback, String architecture, int maxLatency,
-			String architecture, int maxLatency, int maxIdleTime) {
+			int maxIdleTime) {
 		this.ioExecutor = ioExecutor;
-		this.scheduler = scheduler;
 		this.appContext = appContext;
 		this.locationUtils = locationUtils;
 		this.reporter = reporter;
@@ -167,7 +152,6 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		// This tag will prevent Huawei's powermanager from killing us.
 		wakeLock = pm.newWakeLock(PARTIAL_WAKE_LOCK, "LocationManagerService");
 		wakeLock.setReferenceCounted(false);
-		connectionStatusLock = new ReentrantLock();
 	}
 
 	@Override
@@ -220,11 +204,11 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		if (LOG.isLoggable(INFO)) {
 			Scanner stdout = new Scanner(torProcess.getInputStream());
 			Scanner stderr = new Scanner(torProcess.getErrorStream());
-			while (stdout.hasNextLine() || stderr.hasNextLine()) {
+			while (stdout.hasNextLine() || stderr.hasNextLine()){
-				if (stdout.hasNextLine()) {
+				if(stdout.hasNextLine()) {
 					LOG.info(stdout.nextLine());
 				}
-				if (stderr.hasNextLine()) {
+				if(stderr.hasNextLine()){
 					LOG.info(stderr.nextLine());
 				}
 			}
@@ -273,11 +257,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		}
 		// Register to receive network status events
 		networkStateReceiver = new NetworkStateReceiver();
-		IntentFilter filter = new IntentFilter();
+		IntentFilter filter = new IntentFilter(CONNECTIVITY_ACTION);
-		filter.addAction(CONNECTIVITY_ACTION);
-		filter.addAction(ACTION_SCREEN_ON);
-		filter.addAction(ACTION_SCREEN_OFF);
-		if (SDK_INT >= 23) filter.addAction(ACTION_DEVICE_IDLE_MODE_CHANGED);
 		appContext.registerReceiver(networkStateReceiver, filter);
 		// Bind a server socket to receive incoming hidden service connections
 		bind();
@@ -614,7 +594,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
-			byte[] commitment, BdfList descriptor) {
+			byte[] commitment, BdfList descriptor, long timeout) {
 		throw new UnsupportedOperationException();
 	}
 
@@ -638,8 +618,6 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	@Override
 	public void orConnStatus(String status, String orName) {
 		if (LOG.isLoggable(INFO)) LOG.info("OR connection " + status);
-		if (status.equals("CLOSED") || status.equals("FAILED"))
-			updateConnectionStatus(); // Check whether we've lost connectivity
 	}
 
 	@Override
@@ -679,7 +657,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		}
 
 		@Override
-		public void onEvent(int event, @Nullable String path) {
+		public void onEvent(int event, String path) {
 			stopWatching();
 			latch.countDown();
 		}
@@ -699,72 +677,53 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private void updateConnectionStatus() {
 		ioExecutor.execute(() -> {
 			if (!running) return;
+
+			Object o = appContext.getSystemService(CONNECTIVITY_SERVICE);
+			ConnectivityManager cm = (ConnectivityManager) o;
+			NetworkInfo net = cm.getActiveNetworkInfo();
+			boolean online = net != null && net.isConnected();
+			boolean wifi = online && net.getType() == TYPE_WIFI;
+			String country = locationUtils.getCurrentCountry();
+			boolean blocked = TorNetworkMetadata.isTorProbablyBlocked(
+					country);
+			Settings s = callback.getSettings();
+			int network = s.getInt(PREF_TOR_NETWORK, PREF_TOR_NETWORK_ALWAYS);
+
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Online: " + online + ", wifi: " + wifi);
+				if ("".equals(country)) LOG.info("Country code unknown");
+				else LOG.info("Country code: " + country);
+			}
+
 			try {
-				connectionStatusLock.lock();
+				if (!online) {
-				updateConnectionStatusLocked();
+					LOG.info("Disabling network, device is offline");
-			} finally {
+					enableNetwork(false);
-				connectionStatusLock.unlock();
+				} else if (blocked) {
+					LOG.info("Disabling network, country is blocked");
+					enableNetwork(false);
+				} else if (network == PREF_TOR_NETWORK_NEVER
+						|| (network == PREF_TOR_NETWORK_WIFI && !wifi)) {
+					LOG.info("Disabling network due to data setting");
+					enableNetwork(false);
+				} else {
+					LOG.info("Enabling network");
+					enableNetwork(true);
+				}
+			} catch (IOException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			}
 		});
 	}
 
-	// Locking: connectionStatusLock
-	private void updateConnectionStatusLocked() {
-		Object o = appContext.getSystemService(CONNECTIVITY_SERVICE);
-		ConnectivityManager cm = (ConnectivityManager) o;
-		NetworkInfo net = cm.getActiveNetworkInfo();
-		boolean online = net != null && net.isConnected();
-		boolean wifi = online && net.getType() == TYPE_WIFI;
-		String country = locationUtils.getCurrentCountry();
-		boolean blocked = TorNetworkMetadata.isTorProbablyBlocked(country);
-		Settings s = callback.getSettings();
-		int network = s.getInt(PREF_TOR_NETWORK, PREF_TOR_NETWORK_ALWAYS);
-
-		if (LOG.isLoggable(INFO)) {
-			LOG.info("Online: " + online + ", wifi: " + wifi);
-			if ("".equals(country)) LOG.info("Country code unknown");
-			else LOG.info("Country code: " + country);
-		}
-
-		try {
-			if (!online) {
-				LOG.info("Disabling network, device is offline");
-				enableNetwork(false);
-			} else if (blocked) {
-				LOG.info("Disabling network, country is blocked");
-				enableNetwork(false);
-			} else if (network == PREF_TOR_NETWORK_NEVER
-					|| (network == PREF_TOR_NETWORK_WIFI && !wifi)) {
-				LOG.info("Disabling network due to data setting");
-				enableNetwork(false);
-			} else {
-				LOG.info("Enabling network");
-				enableNetwork(true);
-			}
-		} catch (IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		}
-	}
-
-	private void scheduleConnectionStatusUpdate() {
-		Future<?> newConnectivityCheck =
-				scheduler.schedule(this::updateConnectionStatus, 1, MINUTES);
-		Future<?> oldConnectivityCheck =
-				connectivityCheck.getAndSet(newConnectivityCheck);
-		if (oldConnectivityCheck != null) oldConnectivityCheck.cancel(false);
-	}
-
 	private class NetworkStateReceiver extends BroadcastReceiver {
 
 		@Override
 		public void onReceive(Context ctx, Intent i) {
 			if (!running) return;
-			String action = i.getAction();
+			if (CONNECTIVITY_ACTION.equals(i.getAction())) {
-			if (LOG.isLoggable(INFO)) LOG.info("Received broadcast " + action);
+				LOG.info("Detected connectivity change");
-			updateConnectionStatus();
+				updateConnectionStatus();
-			if (ACTION_SCREEN_ON.equals(action)
-					|| ACTION_SCREEN_OFF.equals(action)) {
-				scheduleConnectionStatusUpdate();
 			}
 		}
 	}

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

@@ -17,7 +17,6 @@ import org.briarproject.bramble.api.system.LocationUtils;
 import org.briarproject.bramble.util.AndroidUtils;
 
 import java.util.concurrent.Executor;
-import java.util.concurrent.ScheduledExecutorService;
 import java.util.logging.Logger;
 
 import javax.annotation.concurrent.Immutable;
@@ -37,7 +36,6 @@ public class TorPluginFactory implements DuplexPluginFactory {
 	private static final double BACKOFF_BASE = 1.2;
 
 	private final Executor ioExecutor;
-	private final ScheduledExecutorService scheduler;
 	private final Context appContext;
 	private final LocationUtils locationUtils;
 	private final DevReporter reporter;
@@ -45,13 +43,11 @@ public class TorPluginFactory implements DuplexPluginFactory {
 	private final SocketFactory torSocketFactory;
 	private final BackoffFactory backoffFactory;
 
-	public TorPluginFactory(Executor ioExecutor,
+	public TorPluginFactory(Executor ioExecutor, Context appContext,
-			ScheduledExecutorService scheduler, Context appContext,
 			LocationUtils locationUtils, DevReporter reporter,
 			EventBus eventBus, SocketFactory torSocketFactory,
 			BackoffFactory backoffFactory) {
 		this.ioExecutor = ioExecutor;
-		this.scheduler = scheduler;
 		this.appContext = appContext;
 		this.locationUtils = locationUtils;
 		this.reporter = reporter;
@@ -93,9 +89,9 @@ public class TorPluginFactory implements DuplexPluginFactory {
 
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		TorPlugin plugin = new TorPlugin(ioExecutor, scheduler, appContext,
+		TorPlugin plugin = new TorPlugin(ioExecutor, appContext, locationUtils,
-				locationUtils, reporter, torSocketFactory, backoff, callback,
+				reporter, torSocketFactory, backoff, callback, architecture,
-				architecture, MAX_LATENCY, MAX_IDLE_TIME);
+				MAX_LATENCY, MAX_IDLE_TIME);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

bramble-android/src/main/java/org/briarproject/bramble/util/AndroidUtils.java

@@ -1,41 +1,18 @@
 package org.briarproject.bramble.util;
 
-import android.annotation.SuppressLint;
 import android.bluetooth.BluetoothAdapter;
 import android.content.Context;
-import android.net.ConnectivityManager;
-import android.net.Network;
-import android.net.NetworkInfo;
-import android.net.wifi.WifiInfo;
-import android.net.wifi.WifiManager;
 import android.os.Build;
 import android.provider.Settings;
 
 import java.io.File;
-import java.net.InetAddress;
-import java.net.InterfaceAddress;
-import java.net.NetworkInterface;
-import java.net.SocketException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
-import java.util.logging.Logger;
 
-import javax.annotation.Nullable;
-
-import static android.content.Context.CONNECTIVITY_SERVICE;
 import static android.content.Context.MODE_PRIVATE;
-import static android.content.Context.WIFI_SERVICE;
-import static android.os.Build.VERSION.SDK_INT;
-import static java.net.NetworkInterface.getNetworkInterfaces;
-import static java.util.Collections.list;
-import static java.util.logging.Level.INFO;
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.StringUtils.ipToString;
-import static org.briarproject.bramble.util.StringUtils.toHexString;
 
-@SuppressLint("HardwareIds")
 public class AndroidUtils {
 
 	// Fake Bluetooth address returned by BluetoothAdapter on API 23 and later
@@ -46,7 +23,7 @@ public class AndroidUtils {
 	@SuppressWarnings("deprecation")
 	public static Collection<String> getSupportedArchitectures() {
 		List<String> abis = new ArrayList<>();
-		if (SDK_INT >= 21) {
+		if (Build.VERSION.SDK_INT >= 21) {
 			abis.addAll(Arrays.asList(Build.SUPPORTED_ABIS));
 		} else {
 			abis.add(Build.CPU_ABI);
@@ -90,123 +67,4 @@ public class AndroidUtils {
 	public static File getReportDir(Context ctx) {
 		return ctx.getDir(STORED_REPORTS, MODE_PRIVATE);
 	}
-
-	public static void logNetworkState(Context ctx, Logger logger) {
-		if (!logger.isLoggable(INFO)) return;
-
-		Object o = ctx.getSystemService(CONNECTIVITY_SERVICE);
-		if (o == null) throw new AssertionError();
-		ConnectivityManager cm = (ConnectivityManager) o;
-		o = ctx.getApplicationContext().getSystemService(WIFI_SERVICE);
-		if (o == null) throw new AssertionError();
-		WifiManager wm = (WifiManager) o;
-
-		StringBuilder s = new StringBuilder();
-		logWifiInfo(s, wm.getConnectionInfo());
-		logNetworkInfo(s, cm.getActiveNetworkInfo(), true);
-		if (SDK_INT >= 21) {
-			for (Network network : cm.getAllNetworks())
-				logNetworkInfo(s, cm.getNetworkInfo(network), false);
-		} else {
-			for (NetworkInfo info : cm.getAllNetworkInfo())
-				logNetworkInfo(s, info, false);
-		}
-		try {
-			for (NetworkInterface iface : list(getNetworkInterfaces()))
-				logNetworkInterface(s, iface);
-		} catch (SocketException e) {
-			logger.log(WARNING, e.toString(), e);
-		}
-		logger.log(INFO, s.toString());
-	}
-
-	private static void logWifiInfo(StringBuilder s, @Nullable WifiInfo info) {
-		if (info == null) {
-			s.append("Wifi info: null\n");
-			return;
-		}
-		s.append("Wifi info:\n");
-		s.append("\tSSID: ").append(info.getSSID()).append("\n");
-		s.append("\tBSSID: ").append(info.getBSSID()).append("\n");
-		s.append("\tMAC address: ").append(info.getMacAddress()).append("\n");
-		s.append("\tIP address: ")
-				.append(ipToString(info.getIpAddress())).append("\n");
-		s.append("\tSupplicant state: ")
-				.append(info.getSupplicantState()).append("\n");
-		s.append("\tNetwork ID: ").append(info.getNetworkId()).append("\n");
-		s.append("\tLink speed: ").append(info.getLinkSpeed()).append("\n");
-		s.append("\tRSSI: ").append(info.getRssi()).append("\n");
-		if (info.getHiddenSSID()) s.append("\tHidden SSID\n");
-		if (SDK_INT >= 21)
-			s.append("\tFrequency: ").append(info.getFrequency()).append("\n");
-	}
-
-	private static void logNetworkInfo(StringBuilder s,
-			@Nullable NetworkInfo info, boolean active) {
-		if (info == null) {
-			if (active) s.append("Active network info: null\n");
-			else s.append("Network info: null\n");
-			return;
-		}
-		if (active) s.append("Active network info:\n");
-		else s.append("Network info:\n");
-		s.append("\tType: ").append(info.getTypeName())
-				.append(" (").append(info.getType()).append(")\n");
-		s.append("\tSubtype: ").append(info.getSubtypeName())
-				.append(" (").append(info.getSubtype()).append(")\n");
-		s.append("\tState: ").append(info.getState()).append("\n");
-		s.append("\tDetailed state: ")
-				.append(info.getDetailedState()).append("\n");
-		s.append("\tReason: ").append(info.getReason()).append("\n");
-		s.append("\tExtra info: ").append(info.getExtraInfo()).append("\n");
-		if (info.isAvailable()) s.append("\tAvailable\n");
-		if (info.isConnected()) s.append("\tConnected\n");
-		if (info.isConnectedOrConnecting())
-			s.append("\tConnected or connecting\n");
-		if (info.isFailover()) s.append("\tFailover\n");
-		if (info.isRoaming()) s.append("\tRoaming\n");
-	}
-
-	private static void logNetworkInterface(StringBuilder s,
-			NetworkInterface iface) throws SocketException {
-		s.append("Network interface:\n");
-		s.append("\tName: ").append(iface.getName()).append("\n");
-		s.append("\tDisplay name: ")
-				.append(iface.getDisplayName()).append("\n");
-		s.append("\tHardware address: ")
-				.append(hexOrNull(iface.getHardwareAddress())).append("\n");
-		if (iface.isLoopback()) s.append("\tLoopback\n");
-		if (iface.isPointToPoint()) s.append("\tPoint-to-point\n");
-		if (iface.isVirtual()) s.append("\tVirtual\n");
-		if (iface.isUp()) s.append("\tUp\n");
-		if (SDK_INT >= 19)
-			s.append("\tIndex: ").append(iface.getIndex()).append("\n");
-		for (InterfaceAddress addr : iface.getInterfaceAddresses()) {
-			s.append("\tInterface address:\n");
-			logInetAddress(s, addr.getAddress());
-			s.append("\t\tPrefix length: ")
-					.append(addr.getNetworkPrefixLength()).append("\n");
-		}
-	}
-
-	private static void logInetAddress(StringBuilder s, InetAddress addr) {
-		s.append("\t\tAddress: ")
-				.append(hexOrNull(addr.getAddress())).append("\n");
-		s.append("\t\tHost address: ")
-				.append(addr.getHostAddress()).append("\n");
-		if (addr.isLoopbackAddress()) s.append("\t\tLoopback\n");
-		if (addr.isLinkLocalAddress()) s.append("\t\tLink-local\n");
-		if (addr.isSiteLocalAddress()) s.append("\t\tSite-local\n");
-		if (addr.isAnyLocalAddress()) s.append("\t\tAny local (wildcard)\n");
-		if (addr.isMCNodeLocal()) s.append("\t\tMulticast node-local\n");
-		if (addr.isMCLinkLocal()) s.append("\t\tMulticast link-local\n");
-		if (addr.isMCSiteLocal()) s.append("\t\tMulticast site-local\n");
-		if (addr.isMCOrgLocal()) s.append("\t\tMulticast org-local\n");
-		if (addr.isMCGlobal()) s.append("\t\tMulticast global\n");
-	}
-
-	@Nullable
-	private static String hexOrNull(@Nullable byte[] b) {
-		return b == null ? null : toHexString(b);
-	}
 }

bramble-api/src/main/java/org/briarproject/bramble/api/Multiset.java

@@ -1,101 +0,0 @@
-package org.briarproject.bramble.api;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.NoSuchElementException;
-import java.util.Set;
-
-import javax.annotation.concurrent.NotThreadSafe;
-
-@NotThreadSafe
-@NotNullByDefault
-public class Multiset<T> {
-
-	private final Map<T, Integer> map = new HashMap<>();
-
-	private int total = 0;
-
-	/**
-	 * Returns how many items the multiset contains in total.
-	 */
-	public int getTotal() {
-		return total;
-	}
-
-	/**
-	 * Returns how many unique items the multiset contains.
-	 */
-	public int getUnique() {
-		return map.size();
-	}
-
-	/**
-	 * Returns how many of the given item the multiset contains.
-	 */
-	public int getCount(T t) {
-		Integer count = map.get(t);
-		return count == null ? 0 : count;
-	}
-
-	/**
-	 * Adds the given item to the multiset and returns how many of the item
-	 * the multiset now contains.
-	 */
-	public int add(T t) {
-		Integer count = map.get(t);
-		if (count == null) count = 0;
-		map.put(t, count + 1);
-		total++;
-		return count + 1;
-	}
-
-	/**
-	 * Removes the given item from the multiset and returns how many of the
-	 * item the multiset now contains.
-	 * @throws NoSuchElementException if the item is not in the multiset.
-	 */
-	public int remove(T t) {
-		Integer count = map.get(t);
-		if (count == null) throw new NoSuchElementException();
-		if (count == 1) map.remove(t);
-		else map.put(t, count - 1);
-		total--;
-		return count - 1;
-	}
-
-	/**
-	 * Removes all occurrences of the given item from the multiset.
-	 */
-	public int removeAll(T t) {
-		Integer count = map.remove(t);
-		if (count == null) return 0;
-		total -= count;
-		return count;
-	}
-
-	/**
-	 * Returns true if the multiset contains any occurrences of the given item.
-	 */
-	public boolean contains(T t) {
-		return map.containsKey(t);
-	}
-
-	/**
-	 * Removes all items from the multiset.
-	 */
-	public void clear() {
-		map.clear();
-		total = 0;
-	}
-
-	/**
-	 * Returns the set of unique items the multiset contains. The returned set
-	 * is unmodifiable.
-	 */
-	public Set<T> keySet() {
-		return Collections.unmodifiableSet(map.keySet());
-	}
-}

bramble-api/src/main/java/org/briarproject/bramble/api/UnsupportedVersionException.java

@@ -1,9 +0,0 @@
-package org.briarproject.bramble.api;
-
-import java.io.IOException;
-
-/**
- * An exception that indicates an unrecoverable version mismatch.
- */
-public class UnsupportedVersionException extends IOException {
-}

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

@@ -5,7 +5,6 @@ import org.briarproject.bramble.api.data.BdfDictionary;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
-import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.Message;
@@ -94,13 +93,10 @@ public interface ClientHelper {
 
 	BdfList toList(Message m) throws FormatException;
 
-	BdfList toList(Author a);
-
 	byte[] sign(String label, BdfList toSign, byte[] privateKey)
 			throws FormatException, GeneralSecurityException;
 
 	void verifySignature(String label, byte[] sig, byte[] publicKey,
 			BdfList signed) throws FormatException, GeneralSecurityException;
 
-	Author parseAndValidateAuthor(BdfList author) throws FormatException;
 }

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

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

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

@@ -12,32 +12,6 @@ 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

@@ -1,13 +1,11 @@
 package org.briarproject.bramble.api.crypto;
 
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.security.GeneralSecurityException;
 import java.security.SecureRandom;
 
-import javax.annotation.Nullable;
-
-@NotNullByDefault
 public interface CryptoComponent {
 
 	SecretKey generateSecretKey();
@@ -25,46 +23,127 @@ public interface CryptoComponent {
 	KeyParser getMessageKeyParser();
 
 	/**
-	 * Derives another secret key from the given secret key.
+	 * Derives a stream header key from the given master secret.
-	 *
+	 * @param alice whether the key is for use by Alice or Bob.
-	 * @param label a namespaced label indicating the purpose of the derived
-	 * key, to prevent it from being repurposed or colliding with a key derived
-	 * for another purpose
 	 */
-	SecretKey deriveKey(String label, SecretKey k, byte[]... inputs);
+	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
+	 * @return the commitment to the provided public key.
+	 */
+	byte[] deriveKeyCommitment(byte[] publicKey);
 
 	/**
 	 * Derives a common shared secret from two public keys and one of the
 	 * corresponding private keys.
+	 * <p/>
+	 * Part of BQP.
 	 *
-	 * @param label a namespaced label indicating the purpose of this shared
+	 * @param theirPublicKey the ephemeral public key of the remote party
-	 * secret, to prevent it from being repurposed or colliding with a shared
+	 * @param ourKeyPair our ephemeral keypair
-	 * secret derived for another purpose
+	 * @param alice true if ourKeyPair belongs to Alice
-	 * @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(String label, PublicKey theirPublicKey,
+	SecretKey deriveSharedSecret(byte[] theirPublicKey, KeyPair ourKeyPair,
-			KeyPair ourKeyPair, byte[]... inputs)
+			boolean alice) throws GeneralSecurityException;
-			throws GeneralSecurityException;
 
 	/**
-	 * Signs the given byte[] with the given private key.
+	 * Derives the content of a confirmation record.
+	 * <p/>
+	 * Part of BQP.
 	 *
-	 * @param label a namespaced label indicating the purpose of this
+	 * @param sharedSecret the common shared secret
-	 * signature, to prevent it from being repurposed or colliding with a
+	 * @param theirPayload the commit payload from the remote party
-	 * signature created for another purpose
+	 * @param ourPayload the commit payload we sent
+	 * @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 signed data
+	 * Verifies that the given signature is valid for the signedData
-	 * and the given public key.
+	 * and the given publicKey.
 	 *
-	 * @param label a namespaced label indicating the purpose of this
+	 * @param label A label that was specific to this signature
-	 * signature, to prevent it from being repurposed or colliding with a
+	 *              to ensure that the signature cannot be repurposed
-	 * signature created for another purpose
 	 * @return true if the signature was valid, false otherwise.
 	 */
 	boolean verify(String label, byte[] signedData, byte[] publicKey,
@@ -74,22 +153,23 @@ public interface CryptoComponent {
 	 * Returns the hash of 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 hash, to
+	 * @param label A label specific to this hash to ensure that hashes
-	 * prevent it from being repurposed or colliding with a hash created for
+	 *              calculated for distinct purposes don't collide.
-	 * 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(String label, SecretKey macKey, byte[]... inputs);
+	byte[] mac(SecretKey macKey, byte[]... inputs);
 
 	/**
 	 * Encrypts and authenticates the given plaintext so it can be written to
@@ -105,7 +185,6 @@ public interface CryptoComponent {
 	 * given password. Returns null if the ciphertext cannot be decrypted and
 	 * authenticated (for example, if the password is wrong).
 	 */
-	@Nullable
 	byte[] decryptWithPassword(byte[] ciphertext, String password);
 
 	/**

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

@@ -1,19 +0,0 @@
-package org.briarproject.bramble.api.crypto;
-
-public interface CryptoConstants {
-
-	/**
-	 * The maximum length of an agreement public key in bytes.
-	 */
-	int MAX_AGREEMENT_PUBLIC_KEY_BYTES = 32;
-
-	/**
-	 * The maximum length of a signature public key in bytes.
-	 */
-	int MAX_SIGNATURE_PUBLIC_KEY_BYTES = 32;
-
-	/**
-	 * The maximum length of a signature in bytes.
-	 */
-	int MAX_SIGNATURE_BYTES = 64;
-}

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

@@ -1,50 +0,0 @@
-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

@@ -1,32 +0,0 @@
-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/ObjectReader.java

@@ -0,0 +1,11 @@
+package org.briarproject.bramble.api.data;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.io.IOException;
+
+@NotNullByDefault
+public interface ObjectReader<T> {
+
+	T readObject(BdfReader r) throws IOException;
+}

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

@@ -1,7 +0,0 @@
-package org.briarproject.bramble.api.db;
-
-/**
- * Thrown when the database uses a newer schema than the current code.
- */
-public class DataTooNewException extends DbException {
-}

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

@@ -1,8 +0,0 @@
-package org.briarproject.bramble.api.db;
-
-/**
- * Thrown when the database uses an older schema than the current code and
- * cannot be migrated.
- */
-public class DataTooOldException extends DbException {
-}

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

@@ -37,13 +37,8 @@ public interface DatabaseComponent {
 
 	/**
 	 * Opens the database and returns true if the database already existed.
-	 *
-	 * @throws DataTooNewException if the data uses a newer schema than the
-	 * current code
-	 * @throws DataTooOldException if the data uses an older schema than the
-	 * current code and cannot be migrated
 	 */
-	boolean open(@Nullable MigrationListener listener) throws DbException;
+	boolean open() throws DbException;
 
 	/**
 	 * Waits for any open transactions to finish and closes the database.
@@ -259,30 +254,31 @@ public interface DatabaseComponent {
 	Collection<LocalAuthor> getLocalAuthors(Transaction txn) throws DbException;
 
 	/**
-	 * Returns the IDs of any messages that need to be validated.
+	 * Returns the IDs of any messages that need to be validated by the given
+	 * client.
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<MessageId> getMessagesToValidate(Transaction txn)
+	Collection<MessageId> getMessagesToValidate(Transaction txn, ClientId c)
 			throws DbException;
 
 	/**
-	 * Returns the IDs of any messages that are pending delivery due to
+	 * Returns the IDs of any messages that are valid but pending delivery due
-	 * dependencies on other messages.
+	 * to dependencies on other messages for the given client.
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<MessageId> getPendingMessages(Transaction txn)
+	Collection<MessageId> getPendingMessages(Transaction txn, ClientId c)
 			throws DbException;
 
 	/**
-	 * Returns the IDs of any messages that have shared dependents but have
+	 * Returns the IDs of any messages from the given client
-	 * not yet been shared themselves.
+	 * that have a shared dependent, but are still not shared themselves.
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<MessageId> getMessagesToShare(Transaction txn)
+	Collection<MessageId> getMessagesToShare(Transaction txn,
-			throws DbException;
+			ClientId c) throws DbException;
 
 	/**
 	 * Returns the message with the given ID, in serialised form, or null if
@@ -377,16 +373,6 @@ public interface DatabaseComponent {
 	MessageStatus getMessageStatus(Transaction txn, ContactId c, MessageId m)
 			throws DbException;
 
-	/*
-	 * Returns the next time (in milliseconds since the Unix epoch) when a
-	 * message is due to be sent to the given contact. The returned value may
-	 * be zero if a message is due to be sent immediately, or Long.MAX_VALUE if
-	 * no messages are scheduled to be sent.
-	 * <p/>
-	 * Read-only.
-	 */
-	long getNextSendTime(Transaction txn, ContactId c) throws DbException;
-
 	/**
 	 * Returns all settings in the given namespace.
 	 * <p/>

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

@@ -1,11 +0,0 @@
-package org.briarproject.bramble.api.db;
-
-public interface MigrationListener {
-
-	/**
-	 * This is called when a migration is started while opening the database.
-	 * It will be called once for each migration being applied.
-	 */
-	void onMigrationRun();
-
-}

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

@@ -1,13 +1,11 @@
 package org.briarproject.bramble.api.identity;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.util.StringUtils;
+
+import java.io.UnsupportedEncodingException;
 
 import javax.annotation.concurrent.Immutable;
 
-import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
-import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
-
 /**
  * A pseudonym for a user.
  */
@@ -19,25 +17,20 @@ public class Author {
 		NONE, ANONYMOUS, UNKNOWN, UNVERIFIED, VERIFIED, OURSELVES
 	}
 
-	/**
-	 * The current version of the author structure.
-	 */
-	public static final int FORMAT_VERSION = 1;
-
 	private final AuthorId id;
-	private final int formatVersion;
 	private final String name;
 	private final byte[] publicKey;
 
-	public Author(AuthorId id, int formatVersion, String name,
+	public Author(AuthorId id, String name, byte[] publicKey) {
-			byte[] publicKey) {
+		int length;
-		int nameLength = StringUtils.toUtf8(name).length;
+		try {
-		if (nameLength == 0 || nameLength > MAX_AUTHOR_NAME_LENGTH)
+			length = name.getBytes("UTF-8").length;
-			throw new IllegalArgumentException();
+		} catch (UnsupportedEncodingException e) {
-		if (publicKey.length == 0 || publicKey.length > MAX_PUBLIC_KEY_LENGTH)
+			throw new RuntimeException(e);
+		}
+		if (length == 0 || length > AuthorConstants.MAX_AUTHOR_NAME_LENGTH)
 			throw new IllegalArgumentException();
 		this.id = id;
-		this.formatVersion = formatVersion;
 		this.name = name;
 		this.publicKey = publicKey;
 	}
@@ -49,13 +42,6 @@ public class Author {
 		return id;
 	}
 
-	/**
-	 * Returns the version of the author structure used to create the author.
-	 */
-	public int getFormatVersion() {
-		return formatVersion;
-	}
-
 	/**
 	 * Returns the author's name.
 	 */

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

@@ -1,8 +1,5 @@
 package org.briarproject.bramble.api.identity;
 
-import static org.briarproject.bramble.api.crypto.CryptoConstants.MAX_SIGNATURE_BYTES;
-import static org.briarproject.bramble.api.crypto.CryptoConstants.MAX_SIGNATURE_PUBLIC_KEY_BYTES;
-
 public interface AuthorConstants {
 
 	/**
@@ -11,14 +8,26 @@ public interface AuthorConstants {
 	int MAX_AUTHOR_NAME_LENGTH = 50;
 
 	/**
-	 * The maximum length of a public key in bytes. This applies to the
+	 * The maximum length of a public key in bytes.
-	 * signature algorithm used by the current {@link Author format version}.
+	 * <p>
+	 * Public keys use SEC1 format: 0x04 x y, where x and y are unsigned
+	 * big-endian integers.
+	 * <p>
+	 * For a 256-bit elliptic curve, the maximum length is 2 * 256 / 8 + 1.
 	 */
-	int MAX_PUBLIC_KEY_LENGTH = MAX_SIGNATURE_PUBLIC_KEY_BYTES;
+	int MAX_PUBLIC_KEY_LENGTH = 65;
 
 	/**
-	 * The maximum length of a signature in bytes. This applies to the
+	 * The maximum length of a signature in bytes.
-	 * signature algorithm used by the current {@link Author format version}.
+	 * <p>
+	 * A signature is an ASN.1 DER sequence containing two integers, r and s.
+	 * The format is 0x30 len1 0x02 len2 r 0x02 len3 s, where len1 is
+	 * len(0x02 len2 r 0x02 len3 s) as a DER length, len2 is len(r) as a DER
+	 * length, len3 is len(s) as a DER length, and r and s are signed
+	 * big-endian integers of minimal length.
+	 * <p>
+	 * For a 256-bit elliptic curve, the lengths are one byte each, so the
+	 * maximum length is 2 * 256 / 8 + 8.
 	 */
-	int MAX_SIGNATURE_LENGTH = MAX_SIGNATURE_BYTES;
+	int MAX_SIGNATURE_LENGTH = 72;
 }

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

@@ -5,27 +5,8 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 @NotNullByDefault
 public interface AuthorFactory {
 
-	/**
-	 * Creates an author with the current format version and the given name and
-	 * public key.
-	 */
 	Author createAuthor(String name, byte[] publicKey);
 
-	/**
-	 * Creates an author with the given format version, name and public key.
-	 */
-	Author createAuthor(int formatVersion, String name, byte[] publicKey);
-
-	/**
-	 * Creates a local author with the current format version and the given
-	 * name and keys.
-	 */
 	LocalAuthor createLocalAuthor(String name, byte[] publicKey,
 			byte[] privateKey);
-
-	/**
-	 * Creates a local author with the given format version, name and keys.
-	 */
-	LocalAuthor createLocalAuthor(int formatVersion, String name,
-			byte[] publicKey, byte[] privateKey);
 }

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/identity/LocalAuthor.java

@@ -14,9 +14,9 @@ public class LocalAuthor extends Author {
 	private final byte[] privateKey;
 	private final long created;
 
-	public LocalAuthor(AuthorId id, int formatVersion, String name,
+	public LocalAuthor(AuthorId id, String name, byte[] publicKey,
-			byte[] publicKey, byte[] privateKey, long created) {
+			byte[] privateKey, long created) {
-		super(id, formatVersion, name, publicKey);
+		super(id, name, publicKey);
 		this.privateKey = privateKey;
 		this.created = created;
 	}

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

@@ -3,9 +3,9 @@ package org.briarproject.bramble.api.keyagreement;
 public interface KeyAgreementConstants {
 
 	/**
-	 * The current version of the BQP protocol. Version number 89 is reserved.
+	 * The current version of the BQP protocol.
 	 */
-	byte PROTOCOL_VERSION = 4;
+	byte PROTOCOL_VERSION = 2;
 
 	/**
 	 * The length of the record header in bytes.
@@ -22,10 +22,7 @@ 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.
@@ -36,16 +33,4 @@ 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/KeyAgreementListener.java

@@ -2,7 +2,7 @@ package org.briarproject.bramble.api.keyagreement;
 
 import org.briarproject.bramble.api.data.BdfList;
 
-import java.io.IOException;
+import java.util.concurrent.Callable;
 
 /**
  * An class for managing a particular key agreement listener.
@@ -24,11 +24,11 @@ public abstract class KeyAgreementListener {
 	}
 
 	/**
-	 * Blocks until an incoming connection is received and returns it.
+	 * Starts listening for incoming connections, and returns a Callable that
-	 *
+	 * will return a KeyAgreementConnection when an incoming connection is
-	 * @throws IOException if an error occurs or {@link #close()} is called.
+	 * received.
 	 */
-	public abstract KeyAgreementConnection accept() throws IOException;
+	public abstract Callable<KeyAgreementConnection> listen();
 
 	/**
 	 * Closes the underlying server socket.

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

@@ -0,0 +1,15 @@
+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/lifecycle/LifecycleManager.java

@@ -21,25 +21,7 @@ public interface LifecycleManager {
 	 * The result of calling {@link #startServices(String)}.
 	 */
 	enum StartResult {
-		ALREADY_RUNNING,
+		ALREADY_RUNNING, DB_ERROR, SERVICE_ERROR, SUCCESS
-		DB_ERROR,
-		DATA_TOO_OLD_ERROR,
-		DATA_TOO_NEW_ERROR,
-		SERVICE_ERROR,
-		SUCCESS
-	}
-
-	/**
-	 * The state the lifecycle can be in.
-	 * Returned by {@link #getLifecycleState()}
-	 */
-	enum LifecycleState {
-
-		STARTING, MIGRATING_DATABASE, STARTING_SERVICES, RUNNING, STOPPING;
-
-		public boolean isAfter(LifecycleState state) {
-			return ordinal() > state.ordinal();
-		}
 	}
 
 	/**
@@ -89,10 +71,4 @@ public interface LifecycleManager {
 	 * the {@link DatabaseComponent} to be closed before returning.
 	 */
 	void waitForShutdown() throws InterruptedException;
-
-	/**
-	 * Returns the current state of the lifecycle.
-	 */
-	LifecycleState getLifecycleState();
-
 }

bramble-api/src/main/java/org/briarproject/bramble/api/lifecycle/event/LifecycleEvent.java

@@ -1,20 +0,0 @@
-package org.briarproject.bramble.api.lifecycle.event;
-
-import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState;
-
-/**
- * An event that is broadcast when the app enters a new lifecycle state.
- */
-public class LifecycleEvent extends Event {
-
-	private final LifecycleState state;
-
-	public LifecycleEvent(LifecycleState state) {
-		this.state = state;
-	}
-
-	public LifecycleState getLifecycleState() {
-		return state;
-	}
-}

bramble-api/src/main/java/org/briarproject/bramble/api/lifecycle/event/ShutdownEvent.java

@@ -0,0 +1,9 @@
+package org.briarproject.bramble.api.lifecycle.event;
+
+import org.briarproject.bramble.api.event.Event;
+
+/**
+ * An event that is broadcast when the app is shutting down.
+ */
+public class ShutdownEvent extends Event {
+}

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/duplex/DuplexPlugin.java

@@ -36,9 +36,9 @@ public interface DuplexPlugin extends Plugin {
 
 	/**
 	 * Attempts to connect to the remote peer specified in the given descriptor.
-	 * Returns null if no connection can be established.
+	 * Returns null if no connection can be established within the given time.
 	 */
 	@Nullable
 	DuplexTransportConnection createKeyAgreementConnection(
-			byte[] remoteCommitment, BdfList descriptor);
+			byte[] remoteCommitment, BdfList descriptor, long timeout);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/event/BluetoothEnabledEvent.java

@@ -1,15 +0,0 @@
-package org.briarproject.bramble.api.plugin.event;
-
-import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-/**
- * An event that informs the Bluetooth plugin that we have enabled the
- * Bluetooth adapter.
- */
-@Immutable
-@NotNullByDefault
-public class BluetoothEnabledEvent extends Event {
-}

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/event/EnableBluetoothEvent.java

@@ -6,7 +6,7 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import javax.annotation.concurrent.Immutable;
 
 /**
- * An event that asks the Bluetooth plugin to enable the Bluetooth adapter.
+ * An event asks the Bluetooth plugin to enable the Bluetooth adapter.
  */
 @Immutable
 @NotNullByDefault

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

@@ -17,11 +17,6 @@ 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.

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

@@ -36,8 +36,4 @@ 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, client version and descriptor.
+	 * Creates a group with the given client ID and descriptor.
 	 */
-	Group createGroup(ClientId c, int clientVersion, byte[] descriptor);
+	Group createGroup(ClientId c, 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/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 = 4;
+	int PROTOCOL_VERSION = 3;
 
 	/**
 	 * The length of the pseudo-random tag in bytes.
@@ -80,32 +80,4 @@ 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/main/java/org/briarproject/bramble/util/StringUtils.java

@@ -126,10 +126,6 @@ public class StringUtils {
 		return toUtf8(s).length > maxLength;
 	}
 
-	public static boolean isValidMac(String mac) {
-		return MAC.matcher(mac).matches();
-	}
-
 	public static byte[] macToBytes(String mac) {
 		if (!MAC.matcher(mac).matches()) throw new IllegalArgumentException();
 		return fromHexString(mac.replaceAll(":", ""));
@@ -146,14 +142,6 @@ public class StringUtils {
 		return s.toString();
 	}
 
-	public static String ipToString(int ip) {
-		int ip1 = ip & 0xFF;
-		int ip2 = (ip >> 8) & 0xFF;
-		int ip3 = (ip >> 16) & 0xFF;
-		int ip4 = (ip >> 24) & 0xFF;
-		return ip1 + "." + ip2 + "." + ip3 + "." + ip4;
-	}
-
 	public static String getRandomString(int length) {
 		char[] c = new char[length];
 		for (int i = 0; i < length; i++)

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

@@ -2,32 +2,12 @@ package org.briarproject.bramble.test;
 
 import org.briarproject.bramble.api.UniqueId;
 import org.briarproject.bramble.api.crypto.SecretKey;
-import org.briarproject.bramble.api.identity.Author;
-import org.briarproject.bramble.api.identity.AuthorId;
-import org.briarproject.bramble.api.identity.LocalAuthor;
-import org.briarproject.bramble.api.sync.ClientId;
-import org.briarproject.bramble.api.sync.Group;
-import org.briarproject.bramble.api.sync.GroupId;
-import org.briarproject.bramble.api.sync.Message;
-import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.util.IoUtils;
 
 import java.io.File;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.List;
 import java.util.Random;
 import java.util.concurrent.atomic.AtomicInteger;
 
-import static org.briarproject.bramble.api.identity.Author.FORMAT_VERSION;
-import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
-import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
-import static org.briarproject.bramble.api.sync.SyncConstants.MAX_GROUP_DESCRIPTOR_LENGTH;
-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.util.StringUtils.getRandomString;
-
 public class TestUtils {
 
 	private static final AtomicInteger nextTestDir =
@@ -58,85 +38,4 @@ public class TestUtils {
 		return new SecretKey(getRandomBytes(SecretKey.LENGTH));
 	}
 
-	public static LocalAuthor getLocalAuthor() {
-		return getLocalAuthor(1 + random.nextInt(MAX_AUTHOR_NAME_LENGTH));
-	}
-
-	public static LocalAuthor getLocalAuthor(int nameLength) {
-		AuthorId id = new AuthorId(getRandomId());
-		String name = getRandomString(nameLength);
-		byte[] publicKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
-		byte[] privateKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
-		long created = System.currentTimeMillis();
-		return new LocalAuthor(id, FORMAT_VERSION, name, publicKey, privateKey,
-				created);
-	}
-
-	public static Author getAuthor() {
-		return getAuthor(1 + random.nextInt(MAX_AUTHOR_NAME_LENGTH));
-	}
-
-	public static Author getAuthor(int nameLength) {
-		AuthorId id = new AuthorId(getRandomId());
-		String name = getRandomString(nameLength);
-		byte[] publicKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
-		return new Author(id, FORMAT_VERSION, name, publicKey);
-	}
-
-	public static Group getGroup(ClientId clientId) {
-		int descriptorLength = 1 + random.nextInt(MAX_GROUP_DESCRIPTOR_LENGTH);
-		return getGroup(clientId, descriptorLength);
-	}
-
-	public static Group getGroup(ClientId clientId, int descriptorLength) {
-		GroupId groupId = new GroupId(getRandomId());
-		byte[] descriptor = getRandomBytes(descriptorLength);
-		return new Group(groupId, clientId, descriptor);
-	}
-
-	public static Message getMessage(GroupId groupId) {
-		int bodyLength = 1 + random.nextInt(MAX_MESSAGE_BODY_LENGTH);
-		return getMessage(groupId, MESSAGE_HEADER_LENGTH + bodyLength);
-	}
-
-	public static Message getMessage(GroupId groupId, int rawLength) {
-		MessageId id = new MessageId(getRandomId());
-		byte[] raw = getRandomBytes(rawLength);
-		long timestamp = System.currentTimeMillis();
-		return new Message(id, groupId, timestamp, raw);
-	}
-
-	public static double getMedian(Collection<? extends Number> samples) {
-		int size = samples.size();
-		if (size == 0) throw new IllegalArgumentException();
-		List<Double> sorted = new ArrayList<>(size);
-		for (Number n : samples) sorted.add(n.doubleValue());
-		Collections.sort(sorted);
-		if (size % 2 == 1) return sorted.get(size / 2);
-		double low = sorted.get(size / 2 - 1), high = sorted.get(size / 2);
-		return (low + high) / 2;
-	}
-
-	public static double getMean(Collection<? extends Number> samples) {
-		if (samples.isEmpty()) throw new IllegalArgumentException();
-		double sum = 0;
-		for (Number n : samples) sum += n.doubleValue();
-		return sum / samples.size();
-	}
-
-	public static double getVariance(Collection<? extends Number> samples) {
-		if (samples.size() < 2) throw new IllegalArgumentException();
-		double mean = getMean(samples);
-		double sumSquareDiff = 0;
-		for (Number n : samples) {
-			double diff = n.doubleValue() - mean;
-			sumSquareDiff += diff * diff;
-		}
-		return sumSquareDiff / (samples.size() - 1);
-	}
-
-	public static double getStandardDeviation(
-			Collection<? extends Number> samples) {
-		return Math.sqrt(getVariance(samples));
-	}
 }

bramble-core/build.gradle

@@ -9,15 +9,12 @@ apply plugin: 'witness'
 dependencies {
 	implementation project(path: ':bramble-api', configuration: 'default')
 	implementation 'com.madgag.spongycastle:core:1.58.0.0'
-	implementation 'com.h2database:h2:1.4.192' // The last version that supports Java 1.6
+	implementation 'com.h2database:h2:1.4.192' // This is the last version that supports Java 1.6
 	implementation 'org.bitlet:weupnp:0.1.4'
-	implementation 'net.i2p.crypto:eddsa:0.2.0'
-	implementation 'org.whispersystems:curve25519-java:0.4.1'
 
 	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"
@@ -40,21 +37,18 @@ dependencyVerification {
 			'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',
 	]
 }
 

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

@@ -15,8 +15,6 @@ 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.identity.Author;
-import org.briarproject.bramble.api.identity.AuthorFactory;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.Message;
@@ -34,12 +32,7 @@ import java.util.Map.Entry;
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
-import static org.briarproject.bramble.api.identity.Author.FORMAT_VERSION;
-import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
-import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
 import static org.briarproject.bramble.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
-import static org.briarproject.bramble.util.ValidationUtils.checkLength;
-import static org.briarproject.bramble.util.ValidationUtils.checkSize;
 
 @Immutable
 @NotNullByDefault
@@ -58,14 +51,12 @@ class ClientHelperImpl implements ClientHelper {
 	private final MetadataParser metadataParser;
 	private final MetadataEncoder metadataEncoder;
 	private final CryptoComponent crypto;
-	private final AuthorFactory authorFactory;
 
 	@Inject
 	ClientHelperImpl(DatabaseComponent db, MessageFactory messageFactory,
 			BdfReaderFactory bdfReaderFactory,
 			BdfWriterFactory bdfWriterFactory, MetadataParser metadataParser,
-			MetadataEncoder metadataEncoder, CryptoComponent crypto,
+			MetadataEncoder metadataEncoder, CryptoComponent crypto) {
-			AuthorFactory authorFactory) {
 		this.db = db;
 		this.messageFactory = messageFactory;
 		this.bdfReaderFactory = bdfReaderFactory;
@@ -73,7 +64,6 @@ class ClientHelperImpl implements ClientHelper {
 		this.metadataParser = metadataParser;
 		this.metadataEncoder = metadataEncoder;
 		this.crypto = crypto;
-		this.authorFactory = authorFactory;
 	}
 
 	@Override
@@ -351,11 +341,6 @@ class ClientHelperImpl implements ClientHelper {
 				raw.length - MESSAGE_HEADER_LENGTH);
 	}
 
-	@Override
-	public BdfList toList(Author a) {
-		return BdfList.of(a.getFormatVersion(), a.getName(), a.getPublicKey());
-	}
-
 	@Override
 	public byte[] sign(String label, BdfList toSign, byte[] privateKey)
 			throws FormatException, GeneralSecurityException {
@@ -370,16 +355,4 @@ class ClientHelperImpl implements ClientHelper {
 		}
 	}
 
-	@Override
-	public Author parseAndValidateAuthor(BdfList author)
-			throws FormatException {
-		checkSize(author, 3);
-		int formatVersion = author.getLong(0).intValue();
-		if (formatVersion != FORMAT_VERSION) throw new FormatException();
-		String name = author.getString(1);
-		checkLength(name, 1, MAX_AUTHOR_NAME_LENGTH);
-		byte[] publicKey = author.getRaw(2);
-		checkLength(publicKey, 1, MAX_PUBLIC_KEY_LENGTH);
-		return authorFactory.createAuthor(formatVersion, name, publicKey);
-	}
 }

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

@@ -2,6 +2,14 @@ package org.briarproject.bramble.client;
 
 import org.briarproject.bramble.api.client.ClientHelper;
 import org.briarproject.bramble.api.client.ContactGroupFactory;
+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.data.MetadataEncoder;
+import org.briarproject.bramble.api.data.MetadataParser;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.sync.GroupFactory;
+import org.briarproject.bramble.api.sync.MessageFactory;
 
 import dagger.Module;
 import dagger.Provides;
@@ -10,14 +18,19 @@ import dagger.Provides;
 public class ClientModule {
 
 	@Provides
-	ClientHelper provideClientHelper(ClientHelperImpl clientHelper) {
+	ClientHelper provideClientHelper(DatabaseComponent db,
-		return clientHelper;
+			MessageFactory messageFactory, BdfReaderFactory bdfReaderFactory,
+			BdfWriterFactory bdfWriterFactory, MetadataParser metadataParser,
+			MetadataEncoder metadataEncoder, CryptoComponent cryptoComponent) {
+		return new ClientHelperImpl(db, messageFactory, bdfReaderFactory,
+				bdfWriterFactory, metadataParser, metadataEncoder,
+				cryptoComponent);
 	}
 
 	@Provides
-	ContactGroupFactory provideContactGroupFactory(
+	ContactGroupFactory provideContactGroupFactory(GroupFactory groupFactory,
-			ContactGroupFactoryImpl contactGroupFactory) {
+			ClientHelper clientHelper) {
-		return contactGroupFactory;
+		return new ContactGroupFactoryImpl(groupFactory, clientHelper);
 	}
 
 }

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

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

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

@@ -43,7 +43,6 @@ import javax.inject.Inject;
 
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.api.identity.Author.FORMAT_VERSION;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_SIGNATURE_LENGTH;
@@ -142,10 +141,8 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		}
 
 		// Derive the header keys for the transport streams
-		SecretKey aliceHeaderKey = crypto.deriveKey(ALICE_KEY_LABEL,
+		SecretKey aliceHeaderKey = crypto.deriveHeaderKey(masterSecret, true);
-				masterSecret, new byte[] {PROTOCOL_VERSION});
+		SecretKey bobHeaderKey = crypto.deriveHeaderKey(masterSecret, false);
-		SecretKey bobHeaderKey = crypto.deriveKey(BOB_KEY_LABEL, masterSecret,
-				new byte[] {PROTOCOL_VERSION});
 
 		// Create the readers
 		InputStream streamReader =
@@ -159,10 +156,8 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		BdfWriter w = bdfWriterFactory.createWriter(streamWriter);
 
 		// Derive the nonces to be signed
-		byte[] aliceNonce = crypto.mac(ALICE_NONCE_LABEL, masterSecret,
+		byte[] aliceNonce = crypto.deriveSignatureNonce(masterSecret, true);
-				new byte[] {PROTOCOL_VERSION});
+		byte[] bobNonce = crypto.deriveSignatureNonce(masterSecret, false);
-		byte[] bobNonce = crypto.mac(BOB_NONCE_LABEL, masterSecret,
-				new byte[] {PROTOCOL_VERSION});
 
 		// Exchange pseudonyms, signed nonces, and timestamps
 		long localTimestamp = clock.currentTimeMillis();
@@ -201,8 +196,8 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 
 		try {
 			// Add the contact
-			ContactId contactId = addContact(remoteAuthor, timestamp,
+			ContactId contactId = addContact(remoteAuthor, masterSecret,
-					remoteProperties);
+					timestamp, alice, remoteProperties);
 			// Reuse the connection as a transport connection
 			connectionManager.manageOutgoingConnection(contactId, transportId,
 					conn);
@@ -228,7 +223,6 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 
 		// Write the name, public key and signature
 		w.writeListStart();
-		w.writeLong(localAuthor.getFormatVersion());
 		w.writeString(localAuthor.getName());
 		w.writeRaw(localAuthor.getPublicKey());
 		w.writeRaw(sig);
@@ -238,16 +232,11 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 
 	private Author receivePseudonym(BdfReader r, byte[] nonce)
 			throws GeneralSecurityException, IOException {
-		// Read the format version, name, public key and signature
+		// Read the name, public key and signature
 		r.readListStart();
-		int formatVersion = (int) r.readLong();
-		if (formatVersion != FORMAT_VERSION) throw new FormatException();
 		String name = r.readString(MAX_AUTHOR_NAME_LENGTH);
-		if (name.isEmpty()) throw new FormatException();
 		byte[] publicKey = r.readRaw(MAX_PUBLIC_KEY_LENGTH);
-		if (publicKey.length == 0) throw new FormatException();
 		byte[] sig = r.readRaw(MAX_SIGNATURE_LENGTH);
-		if (sig.length == 0) throw new FormatException();
 		r.readListEnd();
 		LOG.info("Received pseudonym");
 		// Verify the signature
@@ -256,7 +245,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 				LOG.info("Invalid signature");
 			throw new GeneralSecurityException();
 		}
-		return authorFactory.createAuthor(formatVersion, name, publicKey);
+		return authorFactory.createAuthor(name, publicKey);
 	}
 
 	private void sendTimestamp(BdfWriter w, long timestamp)
@@ -305,15 +294,15 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		return remote;
 	}
 
-	private ContactId addContact(Author remoteAuthor, long timestamp,
+	private ContactId addContact(Author remoteAuthor, SecretKey master,
+			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(), masterSecret, timestamp, alice,
+					localAuthor.getId(), master, timestamp, alice, true, true);
-					true, true);
 			transportPropertyManager.addRemoteProperties(txn, contactId,
 					remoteProperties);
 			db.commitTransaction(txn);
@@ -323,7 +312,8 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		return contactId;
 	}
 
-	private void tryToClose(DuplexTransportConnection conn, boolean exception) {
+	private void tryToClose(DuplexTransportConnection conn,
+			boolean exception) {
 		try {
 			LOG.info("Closing connection");
 			conn.getReader().dispose(exception, true);

bramble-core/src/main/java/org/briarproject/bramble/crypto/Blake2sDigest.java

@@ -0,0 +1,547 @@
+package org.briarproject.bramble.crypto;
+
+/*
+  The BLAKE2 cryptographic hash function was designed by Jean-
+  Philippe Aumasson, Samuel Neves, Zooko Wilcox-O'Hearn, and Christian
+  Winnerlein.
+
+  Reference Implementation and Description can be found at: https://blake2.net/
+  RFC: https://tools.ietf.org/html/rfc7693
+
+  This implementation does not support the Tree Hashing Mode.
+
+  For unkeyed hashing, developers adapting BLAKE2 to ASN.1 - based
+  message formats SHOULD use the OID tree at x = 1.3.6.1.4.1.1722.12.2.
+
+         Algorithm     | Target | Collision | Hash | Hash ASN.1 |
+            Identifier |  Arch  |  Security |  nn  | OID Suffix |
+        ---------------+--------+-----------+------+------------+
+         id-blake2s128 | 32-bit |   2**64   |  16  |   x.2.4    |
+         id-blake2s160 | 32-bit |   2**80   |  20  |   x.2.5    |
+         id-blake2s224 | 32-bit |   2**112  |  28  |   x.2.7    |
+         id-blake2s256 | 32-bit |   2**128  |  32  |   x.2.8    |
+        ---------------+--------+-----------+------+------------+
+
+  Based on the BouncyCastle implementation of BLAKE2b. License:
+
+  Copyright (c) 2000 - 2015 The Legion of the Bouncy Castle Inc.
+  (http://www.bouncycastle.org)
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+ */
+
+import org.spongycastle.crypto.ExtendedDigest;
+import org.spongycastle.util.Arrays;
+
+/**
+ * Implementation of the cryptographic hash function BLAKE2s.
+ * <p/>
+ * BLAKE2s offers a built-in keying mechanism to be used directly
+ * for authentication ("Prefix-MAC") rather than a HMAC construction.
+ * <p/>
+ * BLAKE2s offers a built-in support for a salt for randomized hashing
+ * and a personal string for defining a unique hash function for each application.
+ * <p/>
+ * BLAKE2s is optimized for 32-bit platforms and produces digests of any size
+ * between 1 and 32 bytes.
+ */
+public class Blake2sDigest implements ExtendedDigest {
+	/** BLAKE2s Initialization Vector **/
+	private static final int blake2s_IV[] =
+			// Produced from the square root of primes 2, 3, 5, 7, 11, 13, 17, 19.
+			// The same as SHA-256 IV.
+			{
+					0x6a09e667, 0xbb67ae85, 0x3c6ef372,
+					0xa54ff53a, 0x510e527f, 0x9b05688c,
+					0x1f83d9ab, 0x5be0cd19
+			};
+
+	/** Message word permutations **/
+	private static final byte[][] blake2s_sigma =
+			{
+					{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 },
+					{ 14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3 },
+					{ 11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4 },
+					{ 7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8 },
+					{ 9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13 },
+					{ 2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9 },
+					{ 12, 5, 1, 15, 14, 13, 4, 10, 0, 7, 6, 3, 9, 2, 8, 11 },
+					{ 13, 11, 7, 14, 12, 1, 3, 9, 5, 0, 15, 4, 8, 6, 2, 10 },
+					{ 6, 15, 14, 9, 11, 3, 0, 8, 12, 2, 13, 7, 1, 4, 10, 5 },
+					{ 10, 2, 8, 4, 7, 6, 1, 5, 15, 11, 9, 14, 3, 12, 13, 0 }
+			};
+
+	private static final int ROUNDS = 10; // to use for Catenas H'
+	private static final int BLOCK_LENGTH_BYTES = 64;// bytes
+
+	// General parameters:
+	private int digestLength = 32; // 1- 32 bytes
+	private int keyLength = 0; // 0 - 32 bytes for keyed hashing for MAC
+	private byte[] salt = null;
+	private byte[] personalization = null;
+	private byte[] key = null;
+
+	// Tree hashing parameters:
+	// Because this class does not implement the Tree Hashing Mode,
+	// these parameters can be treated as constants (see init() function)
+	/*
+	 * private int fanout = 1; // 0-255
+	 * private int depth = 1; // 1 - 255
+	 * private int leafLength= 0;
+	 * private long nodeOffset = 0L;
+	 * private int nodeDepth = 0;
+	 * private int innerHashLength = 0;
+	 */
+
+	/**
+	 * Whenever this buffer overflows, it will be processed in the compress()
+	 * function. For performance issues, long messages will not use this buffer.
+	 */
+	private byte[] buffer = null;
+	/** Position of last inserted byte **/
+	private int bufferPos = 0;// a value from 0 up to BLOCK_LENGTH_BYTES
+
+	/** Internal state, in the BLAKE2 paper it is called v **/
+	private int[] internalState = new int[16];
+	/** State vector, in the BLAKE2 paper it is called h **/
+	private int[] chainValue = null;
+
+	// counter (counts bytes): Length up to 2^64 are supported
+	/** holds least significant bits of counter **/
+	private int t0 = 0;
+	/** holds most significant bits of counter **/
+	private int t1 = 0;
+	/** finalization flag, for last block: ~0 **/
+	private int f0 = 0;
+
+	// For Tree Hashing Mode, not used here:
+	// private long f1 = 0L; // finalization flag, for last node: ~0L
+
+	/**
+	 * BLAKE2s-256 for hashing.
+	 */
+	public Blake2sDigest() {
+		this(256);
+	}
+
+	public Blake2sDigest(Blake2sDigest digest) {
+		this.bufferPos = digest.bufferPos;
+		this.buffer = Arrays.clone(digest.buffer);
+		this.keyLength = digest.keyLength;
+		this.key = Arrays.clone(digest.key);
+		this.digestLength = digest.digestLength;
+		this.chainValue = Arrays.clone(digest.chainValue);
+		this.personalization = Arrays.clone(digest.personalization);
+	}
+
+	/**
+	 * BLAKE2s for hashing.
+	 *
+	 * @param digestBits the desired digest length in bits. Must be one of
+	 *                     [128, 160, 224, 256].
+	 */
+	public Blake2sDigest(int digestBits) {
+		if (digestBits != 128 && digestBits != 160 &&
+				digestBits != 224 && digestBits != 256) {
+			throw new IllegalArgumentException(
+					"BLAKE2s digest restricted to one of [128, 160, 224, 256]");
+		}
+		buffer = new byte[BLOCK_LENGTH_BYTES];
+		keyLength = 0;
+		digestLength = digestBits / 8;
+		init();
+	}
+
+	/**
+	 * BLAKE2s for authentication ("Prefix-MAC mode").
+	 * <p/>
+	 * After calling the doFinal() method, the key will remain to be used for
+	 * further computations of this instance. The key can be overwritten using
+	 * the clearKey() method.
+	 *
+	 * @param key a key up to 32 bytes or null
+	 */
+	public Blake2sDigest(byte[] key) {
+		buffer = new byte[BLOCK_LENGTH_BYTES];
+		if (key != null) {
+			if (key.length > 32) {
+				throw new IllegalArgumentException(
+						"Keys > 32 are not supported");
+			}
+			this.key = new byte[key.length];
+			System.arraycopy(key, 0, this.key, 0, key.length);
+
+			keyLength = key.length;
+			System.arraycopy(key, 0, buffer, 0, key.length);
+			bufferPos = BLOCK_LENGTH_BYTES; // zero padding
+		}
+		digestLength = 32;
+		init();
+	}
+
+	/**
+	 * BLAKE2s with key, required digest length, salt and personalization.
+	 * <p/>
+	 * After calling the doFinal() method, the key, the salt and the personal
+	 * string will remain and might be used for further computations with this
+	 * instance. The key can be overwritten using the clearKey() method, the
+	 * salt (pepper) can be overwritten using the clearSalt() method.
+	 *
+	 * @param key a key up to 32 bytes or null
+	 * @param digestBytes from 1 up to 32 bytes
+	 * @param salt 8 bytes or null
+	 * @param personalization 8 bytes or null
+	 */
+	public Blake2sDigest(byte[] key, int digestBytes, byte[] salt,
+			byte[] personalization) {
+		buffer = new byte[BLOCK_LENGTH_BYTES];
+		if (digestBytes < 1 || digestBytes > 32) {
+			throw new IllegalArgumentException(
+					"Invalid digest length (required: 1 - 32)");
+		}
+		digestLength = digestBytes;
+		if (salt != null) {
+			if (salt.length != 8) {
+				throw new IllegalArgumentException(
+						"Salt length must be exactly 8 bytes");
+			}
+			this.salt = new byte[8];
+			System.arraycopy(salt, 0, this.salt, 0, salt.length);
+		}
+		if (personalization != null) {
+			if (personalization.length != 8) {
+				throw new IllegalArgumentException(
+						"Personalization length must be exactly 8 bytes");
+			}
+			this.personalization = new byte[8];
+			System.arraycopy(personalization, 0, this.personalization, 0,
+					personalization.length);
+		}
+		if (key != null) {
+			if (key.length > 32) {
+				throw new IllegalArgumentException(
+						"Keys > 32 bytes are not supported");
+			}
+			this.key = new byte[key.length];
+			System.arraycopy(key, 0, this.key, 0, key.length);
+
+			keyLength = key.length;
+			System.arraycopy(key, 0, buffer, 0, key.length);
+			bufferPos = BLOCK_LENGTH_BYTES; // zero padding
+		}
+		init();
+	}
+
+	// initialize chainValue
+	private void init() {
+		if (chainValue == null) {
+			chainValue = new int[8];
+
+			chainValue[0] = blake2s_IV[0]
+					^ (digestLength | (keyLength << 8) | 0x1010000);
+			// 0x1010000 = ((fanout << 16) | (depth << 24));
+			// with fanout = 1; depth = 0;
+			chainValue[1] = blake2s_IV[1];// ^ leafLength; with leafLength = 0;
+			chainValue[2] = blake2s_IV[2];// ^ nodeOffset; with nodeOffset = 0;
+			chainValue[3] = blake2s_IV[3];// ^ ( (nodeOffset << 32) |
+			// (nodeDepth << 16) | (innerHashLength << 24) );
+			// with nodeDepth = 0; innerHashLength = 0;
+
+			chainValue[4] = blake2s_IV[4];
+			chainValue[5] = blake2s_IV[5];
+			if (salt != null) {
+				chainValue[4] ^= (bytes2int(salt, 0));
+				chainValue[5] ^= (bytes2int(salt, 4));
+			}
+
+			chainValue[6] = blake2s_IV[6];
+			chainValue[7] = blake2s_IV[7];
+			if (personalization != null) {
+				chainValue[6] ^= (bytes2int(personalization, 0));
+				chainValue[7] ^= (bytes2int(personalization, 4));
+			}
+		}
+	}
+
+	private void initializeInternalState() {
+		// initialize v:
+		System.arraycopy(chainValue, 0, internalState, 0, chainValue.length);
+		System.arraycopy(blake2s_IV, 0, internalState, chainValue.length, 4);
+		internalState[12] = t0 ^ blake2s_IV[4];
+		internalState[13] = t1 ^ blake2s_IV[5];
+		internalState[14] = f0 ^ blake2s_IV[6];
+		internalState[15] = blake2s_IV[7];// ^ f1 with f1 = 0
+	}
+
+	/**
+	 * Update the message digest with a single byte.
+	 *
+	 * @param b the input byte to be entered.
+	 */
+	public void update(byte b) {
+		int remainingLength; // left bytes of buffer
+
+		// process the buffer if full else add to buffer:
+		remainingLength = BLOCK_LENGTH_BYTES - bufferPos;
+		if (remainingLength == 0) { // full buffer
+			t0 += BLOCK_LENGTH_BYTES;
+			if (t0 == 0) { // if message > 2^32
+				t1++;
+			}
+			compress(buffer, 0);
+			Arrays.fill(buffer, (byte)0);// clear buffer
+			buffer[0] = b;
+			bufferPos = 1;
+		} else {
+			buffer[bufferPos] = b;
+			bufferPos++;
+		}
+	}
+
+	/**
+	 * Update the message digest with a block of bytes.
+	 *
+	 * @param message the byte array containing the data.
+	 * @param offset the offset into the byte array where the data starts.
+	 * @param len the length of the data.
+	 */
+	public void update(byte[] message, int offset, int len) {
+		if (message == null || len == 0)
+			return;
+
+		int remainingLength = 0; // left bytes of buffer
+
+		if (bufferPos != 0) { // commenced, incomplete buffer
+
+			// complete the buffer:
+			remainingLength = BLOCK_LENGTH_BYTES - bufferPos;
+			if (remainingLength < len) { // full buffer + at least 1 byte
+				System.arraycopy(message, offset, buffer, bufferPos,
+						remainingLength);
+				t0 += BLOCK_LENGTH_BYTES;
+				if (t0 == 0) { // if message > 2^32
+					t1++;
+				}
+				compress(buffer, 0);
+				bufferPos = 0;
+				Arrays.fill(buffer, (byte) 0);// clear buffer
+			} else {
+				System.arraycopy(message, offset, buffer, bufferPos, len);
+				bufferPos += len;
+				return;
+			}
+		}
+
+		// process blocks except last block (also if last block is full)
+		int messagePos;
+		int blockWiseLastPos = offset + len - BLOCK_LENGTH_BYTES;
+		for (messagePos = offset + remainingLength;
+				messagePos < blockWiseLastPos;
+				messagePos += BLOCK_LENGTH_BYTES) { // block wise 64 bytes
+			// without buffer:
+			t0 += BLOCK_LENGTH_BYTES;
+			if (t0 == 0) {
+				t1++;
+			}
+			compress(message, messagePos);
+		}
+
+		// fill the buffer with left bytes, this might be a full block
+		System.arraycopy(message, messagePos, buffer, 0, offset + len
+				- messagePos);
+		bufferPos += offset + len - messagePos;
+	}
+
+	/**
+	 * Close the digest, producing the final digest value. The doFinal() call
+	 * leaves the digest reset. Key, salt and personal string remain.
+	 *
+	 * @param out the array the digest is to be copied into.
+	 * @param outOffset the offset into the out array the digest is to start at.
+	 */
+	public int doFinal(byte[] out, int outOffset) {
+		f0 = 0xFFFFFFFF;
+		t0 += bufferPos;
+		// bufferPos may be < 64, so (t0 == 0) does not work
+		// for 2^32 < message length > 2^32 - 63
+		if ((t0 < 0) && (bufferPos > -t0)) {
+			t1++;
+		}
+		compress(buffer, 0);
+		Arrays.fill(buffer, (byte) 0);// Holds eventually the key if input is null
+		Arrays.fill(internalState, 0);
+
+		for (int i = 0; i < chainValue.length && (i * 4 < digestLength); i++) {
+			byte[] bytes = int2bytes(chainValue[i]);
+
+			if (i * 4 < digestLength - 4) {
+				System.arraycopy(bytes, 0, out, outOffset + i * 4, 4);
+			} else {
+				System.arraycopy(bytes, 0, out, outOffset + i * 4,
+						digestLength - (i * 4));
+			}
+		}
+
+		Arrays.fill(chainValue, 0);
+
+		reset();
+
+		return digestLength;
+	}
+
+	/**
+	 * Reset the digest back to its initial state. The key, the salt and the
+	 * personal string will remain for further computations.
+	 */
+	public void reset() {
+		bufferPos = 0;
+		f0 = 0;
+		t0 = 0;
+		t1 = 0;
+		chainValue = null;
+		if (key != null) {
+			Arrays.fill(buffer, (byte) 0);
+			System.arraycopy(key, 0, buffer, 0, key.length);
+			bufferPos = BLOCK_LENGTH_BYTES; // zero padding
+		}
+		init();
+	}
+
+	private void compress(byte[] message, int messagePos) {
+		initializeInternalState();
+
+		int[] m = new int[16];
+		for (int j = 0; j < 16; j++) {
+			m[j] = bytes2int(message, messagePos + j * 4);
+		}
+
+		for (int round = 0; round < ROUNDS; round++) {
+
+			// G apply to columns of internalState:m[blake2s_sigma[round][2 *
+			// blockPos]] /+1
+			G(m[blake2s_sigma[round][0]], m[blake2s_sigma[round][1]], 0, 4, 8,
+					12);
+			G(m[blake2s_sigma[round][2]], m[blake2s_sigma[round][3]], 1, 5, 9,
+					13);
+			G(m[blake2s_sigma[round][4]], m[blake2s_sigma[round][5]], 2, 6, 10,
+					14);
+			G(m[blake2s_sigma[round][6]], m[blake2s_sigma[round][7]], 3, 7, 11,
+					15);
+			// G apply to diagonals of internalState:
+			G(m[blake2s_sigma[round][8]], m[blake2s_sigma[round][9]], 0, 5, 10,
+					15);
+			G(m[blake2s_sigma[round][10]], m[blake2s_sigma[round][11]], 1, 6,
+					11, 12);
+			G(m[blake2s_sigma[round][12]], m[blake2s_sigma[round][13]], 2, 7,
+					8, 13);
+			G(m[blake2s_sigma[round][14]], m[blake2s_sigma[round][15]], 3, 4,
+					9, 14);
+		}
+
+		// update chain values:
+		for (int offset = 0; offset < chainValue.length; offset++) {
+			chainValue[offset] = chainValue[offset] ^ internalState[offset]
+					^ internalState[offset + 8];
+		}
+	}
+
+	private void G(int m1, int m2, int posA, int posB, int posC, int posD) {
+		internalState[posA] = internalState[posA] + internalState[posB] + m1;
+		internalState[posD] = rotr32(internalState[posD] ^ internalState[posA],
+				16);
+		internalState[posC] = internalState[posC] + internalState[posD];
+		internalState[posB] = rotr32(internalState[posB] ^ internalState[posC],
+				12);
+		internalState[posA] = internalState[posA] + internalState[posB] + m2;
+		internalState[posD] = rotr32(internalState[posD] ^ internalState[posA],
+				8);
+		internalState[posC] = internalState[posC] + internalState[posD];
+		internalState[posB] = rotr32(internalState[posB] ^ internalState[posC],
+				7);
+	}
+
+	private int rotr32(int x, int rot) {
+		return x >>> rot | (x << (32 - rot));
+	}
+
+	// convert one int value in byte array
+	// little-endian byte order!
+	private byte[] int2bytes(int intValue) {
+		return new byte[] {
+				(byte) intValue, (byte) (intValue >> 8),
+				(byte) (intValue >> 16), (byte) (intValue >> 24)
+		};
+	}
+
+	// little-endian byte order!
+	private int bytes2int(byte[] byteArray, int offset) {
+		return (((int) byteArray[offset] & 0xFF)
+				| (((int) byteArray[offset + 1] & 0xFF) << 8)
+				| (((int) byteArray[offset + 2] & 0xFF) << 16)
+				| (((int) byteArray[offset + 3] & 0xFF) << 24));
+	}
+
+	/**
+	 * Return the algorithm name.
+	 *
+	 * @return the algorithm name
+	 */
+	public String getAlgorithmName() {
+		return "BLAKE2s";
+	}
+
+	/**
+	 * Return the size in bytes of the digest produced by this message digest.
+	 *
+	 * @return the size in bytes of the digest produced by this message digest.
+	 */
+	public int getDigestSize() {
+		return digestLength;
+	}
+
+	/**
+	 * Return the size in bytes of the internal buffer the digest applies its
+	 * compression function to.
+	 *
+	 * @return byte length of the digest's internal buffer.
+	 */
+	public int getByteLength() {
+		return BLOCK_LENGTH_BYTES;
+	}
+
+	/**
+	 * Overwrite the key if it is no longer used (zeroization).
+	 */
+	public void clearKey() {
+		if (key != null) {
+			Arrays.fill(key, (byte) 0);
+			Arrays.fill(buffer,  (byte) 0);
+		}
+	}
+
+	/**
+	 * Overwrite the salt (pepper) if it is secret and no longer used
+	 * (zeroization).
+	 */
+	public void clearSalt() {
+		if (salt != null) {
+			Arrays.fill(salt, (byte) 0);
+		}
+	}
+}

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

@@ -1,59 +1,107 @@
 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.nullsafety.NotNullByDefault;
+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;
+import org.spongycastle.crypto.CipherParameters;
 import org.spongycastle.crypto.CryptoException;
 import org.spongycastle.crypto.Digest;
-import org.spongycastle.crypto.digests.Blake2bDigest;
+import org.spongycastle.crypto.agreement.ECDHCBasicAgreement;
-import org.whispersystems.curve25519.Curve25519;
+import org.spongycastle.crypto.digests.SHA256Digest;
-import org.whispersystems.curve25519.Curve25519KeyPair;
+import org.spongycastle.crypto.generators.ECKeyPairGenerator;
+import org.spongycastle.crypto.generators.PKCS5S2ParametersGenerator;
+import org.spongycastle.crypto.params.ECKeyGenerationParameters;
+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;
 import java.security.SecureRandom;
 import java.security.Security;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 import java.util.logging.Logger;
 
-import javax.annotation.Nullable;
 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;
 
-@NotNullByDefault
 class CryptoComponentImpl implements CryptoComponent {
 
 	private static final Logger LOG =
 			Logger.getLogger(CryptoComponentImpl.class.getName());
 
+	private static final int AGREEMENT_KEY_PAIR_BITS = 256;
 	private static final int SIGNATURE_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_FORMAT_SCRYPT = 0;
+	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 PasswordBasedKdf passwordBasedKdf;
+	private final ECKeyPairGenerator agreementKeyPairGenerator;
-	private final Curve25519 curve25519;
+	private final ECKeyPairGenerator signatureKeyPairGenerator;
-	private final KeyPairGenerator signatureKeyPairGenerator;
 	private final KeyParser agreementKeyParser, signatureKeyParser;
 	private final MessageEncrypter messageEncrypter;
 
 	@Inject
-	CryptoComponentImpl(SecureRandomProvider secureRandomProvider,
+	CryptoComponentImpl(SecureRandomProvider secureRandomProvider) {
-			PasswordBasedKdf passwordBasedKdf) {
 		if (LOG.isLoggable(INFO)) {
 			SecureRandom defaultSecureRandom = new SecureRandom();
 			String name = defaultSecureRandom.getProvider().getName();
@@ -73,13 +121,16 @@ class CryptoComponentImpl implements CryptoComponent {
 			}
 		}
 		secureRandom = new SecureRandom();
-		this.passwordBasedKdf = passwordBasedKdf;
+		ECKeyGenerationParameters params = new ECKeyGenerationParameters(
-		curve25519 = Curve25519.getInstance("java");
+				PARAMETERS, secureRandom);
-		signatureKeyPairGenerator = new KeyPairGenerator();
+		agreementKeyPairGenerator = new ECKeyPairGenerator();
-		signatureKeyPairGenerator.initialize(SIGNATURE_KEY_PAIR_BITS,
+		agreementKeyPairGenerator.init(params);
-				secureRandom);
+		signatureKeyPairGenerator = new ECKeyPairGenerator();
-		agreementKeyParser = new Curve25519KeyParser();
+		signatureKeyPairGenerator.init(params);
-		signatureKeyParser = new EdKeyParser();
+		agreementKeyParser = new Sec1KeyParser(PARAMETERS,
+				AGREEMENT_KEY_PAIR_BITS);
+		signatureKeyParser = new Sec1KeyParser(PARAMETERS,
+				SIGNATURE_KEY_PAIR_BITS);
 		messageEncrypter = new MessageEncrypter(secureRandom);
 	}
 
@@ -123,17 +174,16 @@ class CryptoComponentImpl implements CryptoComponent {
 	// Package access for testing
 	byte[] performRawKeyAgreement(PrivateKey priv, PublicKey pub)
 			throws GeneralSecurityException {
-		if (!(priv instanceof Curve25519PrivateKey))
+		if (!(priv instanceof Sec1PrivateKey))
 			throw new IllegalArgumentException();
-		if (!(pub instanceof Curve25519PublicKey))
+		if (!(pub instanceof Sec1PublicKey))
 			throw new IllegalArgumentException();
+		ECPrivateKeyParameters ecPriv = ((Sec1PrivateKey) priv).getKey();
+		ECPublicKeyParameters ecPub = ((Sec1PublicKey) pub).getKey();
 		long now = System.currentTimeMillis();
-		byte[] secret = curve25519.calculateAgreement(pub.getEncoded(),
+		ECDHCBasicAgreement agreement = new ECDHCBasicAgreement();
-				priv.getEncoded());
+		agreement.init(ecPriv);
-		// If the shared secret is all zeroes, the public key is invalid
+		byte[] secret = agreement.calculateAgreement(ecPub).toByteArray();
-		byte allZero = 0;
-		for (byte b : secret) allZero |= b;
-		if (allZero == 0) throw new GeneralSecurityException();
 		long duration = System.currentTimeMillis() - now;
 		if (LOG.isLoggable(INFO))
 			LOG.info("Deriving shared secret took " + duration + " ms");
@@ -142,10 +192,18 @@ class CryptoComponentImpl implements CryptoComponent {
 
 	@Override
 	public KeyPair generateAgreementKeyPair() {
-		Curve25519KeyPair keyPair = curve25519.generateKeyPair();
+		AsymmetricCipherKeyPair keyPair =
-		PublicKey pub = new Curve25519PublicKey(keyPair.getPublicKey());
+				agreementKeyPairGenerator.generateKeyPair();
-		PrivateKey priv = new Curve25519PrivateKey(keyPair.getPrivateKey());
+		// Return a wrapper that uses the SEC 1 encoding
-		return new KeyPair(pub, priv);
+		ECPublicKeyParameters ecPublicKey =
+				(ECPublicKeyParameters) keyPair.getPublic();
+		PublicKey publicKey = new Sec1PublicKey(ecPublicKey
+		);
+		ECPrivateKeyParameters ecPrivateKey =
+				(ECPrivateKeyParameters) keyPair.getPrivate();
+		PrivateKey privateKey = new Sec1PrivateKey(ecPrivateKey,
+				AGREEMENT_KEY_PAIR_BITS);
+		return new KeyPair(publicKey, privateKey);
 	}
 
 	@Override
@@ -155,12 +213,17 @@ class CryptoComponentImpl implements CryptoComponent {
 
 	@Override
 	public KeyPair generateSignatureKeyPair() {
-		java.security.KeyPair keyPair =
+		AsymmetricCipherKeyPair keyPair =
 				signatureKeyPairGenerator.generateKeyPair();
-		EdDSAPublicKey edPublicKey = (EdDSAPublicKey) keyPair.getPublic();
+		// Return a wrapper that uses the SEC 1 encoding
-		PublicKey publicKey = new EdPublicKey(edPublicKey.getAbyte());
+		ECPublicKeyParameters ecPublicKey =
-		EdDSAPrivateKey edPrivateKey = (EdDSAPrivateKey) keyPair.getPrivate();
+				(ECPublicKeyParameters) keyPair.getPublic();
-		PrivateKey privateKey = new EdPrivateKey(edPrivateKey.getSeed());
+		PublicKey publicKey = new Sec1PublicKey(ecPublicKey
+		);
+		ECPrivateKeyParameters ecPrivateKey =
+				(ECPrivateKeyParameters) keyPair.getPrivate();
+		PrivateKey privateKey = new Sec1PrivateKey(ecPrivateKey,
+				SIGNATURE_KEY_PAIR_BITS);
 		return new KeyPair(publicKey, privateKey);
 	}
 
@@ -175,47 +238,205 @@ class CryptoComponentImpl implements CryptoComponent {
 	}
 
 	@Override
-	public SecretKey deriveKey(String label, SecretKey k, byte[]... inputs) {
+	public SecretKey deriveHeaderKey(SecretKey master,
-		byte[] mac = mac(label, k, inputs);
+			boolean alice) {
-		if (mac.length != SecretKey.LENGTH) throw new IllegalStateException();
+		return new SecretKey(macKdf(master, alice ? A_INVITE : B_INVITE));
-		return new SecretKey(mac);
 	}
 
 	@Override
-	public SecretKey deriveSharedSecret(String label, PublicKey theirPublicKey,
+	public SecretKey deriveMacKey(SecretKey master, boolean alice) {
-			KeyPair ourKeyPair, byte[]... inputs)
+		return new SecretKey(macKdf(master, alice ? A_MAC : B_MAC));
-			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();
-		byte[][] hashInputs = new byte[inputs.length + 1][];
+		PublicKey theirPub = agreementKeyParser.parsePublicKey(theirPublicKey);
-		hashInputs[0] = performRawKeyAgreement(ourPriv, theirPublicKey);
+		byte[] raw = performRawKeyAgreement(ourPriv, theirPub);
-		System.arraycopy(inputs, 0, hashInputs, 1, inputs.length);
+		byte[] alicePub, bobPub;
-		byte[] hash = hash(label, hashInputs);
+		if (alice) {
-		if (hash.length != SecretKey.LENGTH) throw new IllegalStateException();
+			alicePub = ourKeyPair.getPublic().getEncoded();
-		return new SecretKey(hash);
+			bobPub = theirPublicKey;
+		} 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 {
-		PrivateKey key = signatureKeyParser.parsePrivateKey(privateKey);
+		Signature signature = new SignatureImpl(secureRandom);
-		Signature sig = new EdSignature();
+		KeyParser keyParser = getSignatureKeyParser();
-		sig.initSign(key);
+		PrivateKey key = keyParser.parsePrivateKey(privateKey);
-		updateSignature(sig, label, toSign);
+		signature.initSign(key);
-		return sig.sign();
+		updateSignature(signature, label, toSign);
+		return signature.sign();
 	}
 
 	@Override
 	public boolean verify(String label, byte[] signedData, byte[] publicKey,
 			byte[] signature) throws GeneralSecurityException {
-		PublicKey key = signatureKeyParser.parsePublicKey(publicKey);
+		Signature sig = new SignatureImpl(secureRandom);
-		Signature sig = new EdSignature();
+		KeyParser keyParser = getSignatureKeyParser();
+		PublicKey key = keyParser.parsePublicKey(publicKey);
 		sig.initVerify(key);
 		updateSignature(sig, label, signedData);
 		return sig.verify(signature);
 	}
 
 	private void updateSignature(Signature signature, String label,
-			byte[] toSign) throws GeneralSecurityException {
+			byte[] toSign) {
 		byte[] labelBytes = StringUtils.toUtf8(label);
 		byte[] length = new byte[INT_32_BYTES];
 		ByteUtils.writeUint32(labelBytes.length, length, 0);
@@ -229,7 +450,7 @@ class CryptoComponentImpl implements CryptoComponent {
 	@Override
 	public byte[] hash(String label, byte[]... inputs) {
 		byte[] labelBytes = StringUtils.toUtf8(label);
-		Digest digest = new Blake2bDigest(256);
+		Digest digest = new Blake2sDigest();
 		byte[] length = new byte[INT_32_BYTES];
 		ByteUtils.writeUint32(labelBytes.length, length, 0);
 		digest.update(length, 0, length.length);
@@ -245,13 +466,14 @@ class CryptoComponentImpl implements CryptoComponent {
 	}
 
 	@Override
-	public byte[] mac(String label, SecretKey macKey, byte[]... inputs) {
+	public int getHashLength() {
-		byte[] labelBytes = StringUtils.toUtf8(label);
+		return HASH_SIZE;
-		Digest mac = new Blake2bDigest(macKey.getBytes(), 32, null, null);
+	}
+
+	@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);
@@ -270,33 +492,23 @@ class CryptoComponentImpl implements CryptoComponent {
 		byte[] salt = new byte[PBKDF_SALT_BYTES];
 		secureRandom.nextBytes(salt);
 		// Calibrate the KDF
-		int cost = passwordBasedKdf.chooseCostParameter();
+		int iterations = chooseIterationCount(PBKDF_TARGET_MILLIS);
 		// Derive the key from the password
-		SecretKey key = passwordBasedKdf.deriveKey(password, salt, cost);
+		SecretKey key = new SecretKey(pbkdf2(password, salt, iterations));
 		// Generate a random IV
 		byte[] iv = new byte[STORAGE_IV_BYTES];
 		secureRandom.nextBytes(iv);
-		// The output contains the format version, salt, cost parameter, IV,
+		// The output contains the salt, iterations, IV, ciphertext and MAC
-		// ciphertext and MAC
+		int outputLen = salt.length + INT_32_BYTES + iv.length + input.length
-		int outputLen = 1 + salt.length + INT_32_BYTES + iv.length
+				+ macBytes;
-				+ input.length + macBytes;
 		byte[] output = new byte[outputLen];
-		int outputOff = 0;
+		System.arraycopy(salt, 0, output, 0, salt.length);
-		// Format version
+		ByteUtils.writeUint32(iterations, output, salt.length);
-		output[outputOff] = PBKDF_FORMAT_SCRYPT;
+		System.arraycopy(iv, 0, output, salt.length + INT_32_BYTES, iv.length);
-		outputOff++;
-		// Salt
-		System.arraycopy(salt, 0, output, outputOff, salt.length);
-		outputOff += salt.length;
-		// Cost parameter
-		ByteUtils.writeUint32(cost, output, outputOff);
-		outputOff += INT_32_BYTES;
-		// IV
-		System.arraycopy(iv, 0, output, outputOff, iv.length);
-		outputOff += iv.length;
 		// Initialise the cipher and encrypt the plaintext
 		try {
 			cipher.init(true, key, iv);
+			int outputOff = salt.length + INT_32_BYTES + iv.length;
 			cipher.process(input, 0, input.length, output, outputOff);
 			return output;
 		} catch (GeneralSecurityException e) {
@@ -305,36 +517,22 @@ class CryptoComponentImpl implements CryptoComponent {
 	}
 
 	@Override
-	@Nullable
 	public byte[] decryptWithPassword(byte[] input, String password) {
 		AuthenticatedCipher cipher = new XSalsa20Poly1305AuthenticatedCipher();
 		int macBytes = cipher.getMacBytes();
-		// The input contains the format version, salt, cost parameter, IV,
+		// The input contains the salt, iterations, IV, ciphertext and MAC
-		// ciphertext and MAC
+		if (input.length < PBKDF_SALT_BYTES + INT_32_BYTES + STORAGE_IV_BYTES
-		if (input.length < 1 + PBKDF_SALT_BYTES + INT_32_BYTES
+				+ macBytes)
-				+ STORAGE_IV_BYTES + macBytes)
 			return null; // Invalid input
-		int inputOff = 0;
-		// Format version
-		byte formatVersion = input[inputOff];
-		inputOff++;
-		if (formatVersion != PBKDF_FORMAT_SCRYPT)
-			return null; // Unknown format
-		// Salt
 		byte[] salt = new byte[PBKDF_SALT_BYTES];
-		System.arraycopy(input, inputOff, salt, 0, salt.length);
+		System.arraycopy(input, 0, salt, 0, salt.length);
-		inputOff += salt.length;
+		long iterations = ByteUtils.readUint32(input, salt.length);
-		// Cost parameter
+		if (iterations < 0 || iterations > Integer.MAX_VALUE)
-		long cost = ByteUtils.readUint32(input, inputOff);
+			return null; // Invalid iteration count
-		inputOff += INT_32_BYTES;
-		if (cost < 2 || cost > Integer.MAX_VALUE)
-			return null; // Invalid cost parameter
-		// IV
 		byte[] iv = new byte[STORAGE_IV_BYTES];
-		System.arraycopy(input, inputOff, iv, 0, iv.length);
+		System.arraycopy(input, salt.length + INT_32_BYTES, iv, 0, iv.length);
-		inputOff += iv.length;
 		// Derive the key from the password
-		SecretKey key = passwordBasedKdf.deriveKey(password, salt, (int) cost);
+		SecretKey key = new SecretKey(pbkdf2(password, salt, (int) iterations));
 		// Initialise the cipher
 		try {
 			cipher.init(false, key, iv);
@@ -343,6 +541,7 @@ class CryptoComponentImpl implements CryptoComponent {
 		}
 		// Try to decrypt the ciphertext (may be invalid)
 		try {
+			int inputOff = salt.length + INT_32_BYTES + iv.length;
 			int inputLen = input.length - inputOff;
 			byte[] output = new byte[inputLen - macBytes];
 			cipher.process(input, inputOff, inputLen, output, 0);
@@ -365,4 +564,88 @@ class CryptoComponentImpl implements CryptoComponent {
 	public String asciiArmour(byte[] b, int lineLength) {
 		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);
+		Digest digest = new SHA256Digest();
+		PKCS5S2ParametersGenerator gen = new PKCS5S2ParametersGenerator(digest);
+		gen.init(utf8, salt, iterations);
+		int keyLengthInBits = SecretKey.LENGTH * 8;
+		CipherParameters p = gen.generateDerivedParameters(keyLengthInBits);
+		return ((KeyParameter) p).getKey();
+	}
+
+	// Package access for testing
+	int chooseIterationCount(int targetMillis) {
+		List<Long> quickSamples = new ArrayList<>(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
+			for (int i = 0; i < PBKDF_SAMPLES; i++) {
+				quickSamples.add(sampleRunningTime(1));
+				slowSamples.add(sampleRunningTime(2));
+			}
+			// Calculate the iteration time and the initialisation time
+			long quickMedian = median(quickSamples);
+			long slowMedian = median(slowSamples);
+			iterationNanos = slowMedian - quickMedian;
+			initNanos = quickMedian - iterationNanos;
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Init: " + initNanos + ", iteration: "
+						+ iterationNanos);
+			}
+		}
+		long targetNanos = targetMillis * 1000L * 1000L;
+		long iterations = (targetNanos - initNanos) / iterationNanos;
+		if (LOG.isLoggable(INFO)) LOG.info("Target iterations: " + iterations);
+		if (iterations < 1) return 1;
+		if (iterations > Integer.MAX_VALUE) return Integer.MAX_VALUE;
+		return (int) iterations;
+	}
+
+	private long sampleRunningTime(int iterations) {
+		byte[] password = {'p', 'a', 's', 's', 'w', 'o', 'r', 'd'};
+		byte[] salt = new byte[PBKDF_SALT_BYTES];
+		int keyLengthInBits = SecretKey.LENGTH * 8;
+		long start = System.nanoTime();
+		Digest digest = new SHA256Digest();
+		PKCS5S2ParametersGenerator gen = new PKCS5S2ParametersGenerator(digest);
+		gen.init(password, salt, iterations);
+		gen.generateDerivedParameters(keyLengthInBits);
+		return System.nanoTime() - start;
+	}
+
+	private long median(List<Long> list) {
+		int size = list.size();
+		if (size == 0) throw new IllegalArgumentException();
+		Collections.sort(list);
+		if (size % 2 == 1) return list.get(size / 2);
+		return list.get(size / 2 - 1) + list.get(size / 2) / 2;
+	}
 }

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

@@ -3,11 +3,9 @@ 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;
 
@@ -67,9 +65,8 @@ public class CryptoModule {
 	@Provides
 	@Singleton
 	CryptoComponent provideCryptoComponent(
-			SecureRandomProvider secureRandomProvider,
+			SecureRandomProvider secureRandomProvider) {
-			ScryptKdf passwordBasedKdf) {
+		return new CryptoComponentImpl(secureRandomProvider);
-		return new CryptoComponentImpl(secureRandomProvider, passwordBasedKdf);
 	}
 
 	@Provides
@@ -77,12 +74,6 @@ public class CryptoModule {
 		return new PasswordStrengthEstimatorImpl();
 	}
 
-	@Provides
-	TransportCrypto provideTransportCrypto(
-			TransportCryptoImpl transportCrypto) {
-		return transportCrypto;
-	}
-
 	@Provides
 	StreamDecrypterFactory provideStreamDecrypterFactory(
 			Provider<AuthenticatedCipher> cipherProvider) {
@@ -90,17 +81,9 @@ public class CryptoModule {
 	}
 
 	@Provides
-	StreamEncrypterFactory provideStreamEncrypterFactory(
+	StreamEncrypterFactory provideStreamEncrypterFactory(CryptoComponent crypto,
-			CryptoComponent crypto, TransportCrypto transportCrypto,
 			Provider<AuthenticatedCipher> cipherProvider) {
-		return new StreamEncrypterFactoryImpl(crypto, transportCrypto,
+		return new StreamEncrypterFactoryImpl(crypto, cipherProvider);
-				cipherProvider);
-	}
-
-	@Provides
-	KeyAgreementCrypto provideKeyAgreementCrypto(
-			KeyAgreementCryptoImpl keyAgreementCrypto) {
-		return keyAgreementCrypto;
 	}
 
 	@Provides

bramble-core/src/main/java/org/briarproject/bramble/crypto/Curve25519KeyParser.java

@@ -1,35 +0,0 @@
-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 Curve25519KeyParser implements KeyParser {
-
-	@Override
-	public PublicKey parsePublicKey(byte[] encodedKey)
-			throws GeneralSecurityException {
-		if (encodedKey.length != 32) throw new GeneralSecurityException();
-		return new Curve25519PublicKey(encodedKey);
-	}
-
-	@Override
-	public PrivateKey parsePrivateKey(byte[] encodedKey)
-			throws GeneralSecurityException {
-		if (encodedKey.length != 32) throw new GeneralSecurityException();
-		return new Curve25519PrivateKey(clamp(encodedKey));
-	}
-
-	static byte[] clamp(byte[] b) {
-		byte[] clamped = new byte[32];
-		System.arraycopy(b, 0, clamped, 0, 32);
-		clamped[0] &= 248;
-		clamped[31] &= 127;
-		clamped[31] |= 64;
-		return clamped;
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/crypto/Curve25519PrivateKey.java

@@ -1,18 +0,0 @@
-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 Curve25519PrivateKey extends Bytes implements PrivateKey {
-
-	Curve25519PrivateKey(byte[] bytes) {
-		super(bytes);
-	}
-
-	@Override
-	public byte[] getEncoded() {
-		return getBytes();
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/crypto/Curve25519PublicKey.java

@@ -1,18 +0,0 @@
-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 Curve25519PublicKey extends Bytes implements PublicKey {
-
-	Curve25519PublicKey(byte[] bytes) {
-		super(bytes);
-	}
-
-	@Override
-	public byte[] getEncoded() {
-		return getBytes();
-	}
-}

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

@@ -1,26 +0,0 @@
-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

@@ -1,18 +0,0 @@
-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

@@ -1,18 +0,0 @@
-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

@@ -1,83 +0,0 @@
-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/EllipticCurveConstants.java

@@ -0,0 +1,32 @@
+package org.briarproject.bramble.crypto;
+
+import org.spongycastle.asn1.teletrust.TeleTrusTNamedCurves;
+import org.spongycastle.asn1.x9.X9ECParameters;
+import org.spongycastle.crypto.params.ECDomainParameters;
+import org.spongycastle.math.ec.ECCurve;
+import org.spongycastle.math.ec.ECMultiplier;
+import org.spongycastle.math.ec.ECPoint;
+import org.spongycastle.math.ec.MontgomeryLadderMultiplier;
+
+import java.math.BigInteger;
+
+/**
+ * Parameters for curve brainpoolp256r1 - see RFC 5639.
+ */
+class EllipticCurveConstants {
+
+	static final ECDomainParameters PARAMETERS;
+
+	static {
+		// Start with the default implementation of the curve
+		X9ECParameters x9 = TeleTrusTNamedCurves.getByName("brainpoolp256r1");
+		// Use a constant-time multiplier
+		ECMultiplier monty = new MontgomeryLadderMultiplier();
+		ECCurve curve = x9.getCurve().configure().setMultiplier(monty).create();
+		BigInteger gX = x9.getG().getAffineXCoord().toBigInteger();
+		BigInteger gY = x9.getG().getAffineYCoord().toBigInteger();
+		ECPoint g = curve.createPoint(gX, gY);
+		// Convert to ECDomainParameters using the new multiplier
+		PARAMETERS = new ECDomainParameters(curve, g, x9.getN(), x9.getH());
+	}
+}

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

@@ -1,56 +0,0 @@
-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/PasswordBasedKdf.java

@@ -1,10 +0,0 @@
-package org.briarproject.bramble.crypto;
-
-import org.briarproject.bramble.api.crypto.SecretKey;
-
-interface PasswordBasedKdf {
-
-	int chooseCostParameter();
-
-	SecretKey deriveKey(String password, byte[] salt, int cost);
-}

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

@@ -1,62 +0,0 @@
-package org.briarproject.bramble.crypto;
-
-import org.briarproject.bramble.api.crypto.SecretKey;
-import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.bramble.util.StringUtils;
-import org.spongycastle.crypto.generators.SCrypt;
-
-import java.util.logging.Logger;
-
-import javax.inject.Inject;
-
-import static java.util.logging.Level.INFO;
-
-class ScryptKdf implements PasswordBasedKdf {
-
-	private static final Logger LOG =
-			Logger.getLogger(ScryptKdf.class.getName());
-
-	private static final int MIN_COST = 256; // Min parameter N
-	private static final int MAX_COST = 1024 * 1024; // Max parameter N
-	private static final int BLOCK_SIZE = 8; // Parameter r
-	private static final int PARALLELIZATION = 1; // Parameter p
-	private static final int TARGET_MS = 1000;
-
-	private final Clock clock;
-
-	@Inject
-	ScryptKdf(Clock clock) {
-		this.clock = clock;
-	}
-
-	@Override
-	public int chooseCostParameter() {
-		// Increase the cost from min to max while measuring performance
-		int cost = MIN_COST;
-		while (cost * 2 <= MAX_COST && measureDuration(cost) * 2 <= TARGET_MS)
-			cost *= 2;
-		if (LOG.isLoggable(INFO))
-			LOG.info("KDF cost parameter " + cost);
-		return cost;
-	}
-
-	private long measureDuration(int cost) {
-		byte[] password = new byte[16], salt = new byte[32];
-		long start = clock.currentTimeMillis();
-		SCrypt.generate(password, salt, cost, BLOCK_SIZE, PARALLELIZATION,
-				SecretKey.LENGTH);
-		return clock.currentTimeMillis() - start;
-	}
-
-	@Override
-	public SecretKey deriveKey(String password, byte[] salt, int cost) {
-		long start = System.currentTimeMillis();
-		byte[] passwordBytes = StringUtils.toUtf8(password);
-		SecretKey k = new SecretKey(SCrypt.generate(passwordBytes, salt, cost,
-				BLOCK_SIZE, PARALLELIZATION, SecretKey.LENGTH));
-		long duration = System.currentTimeMillis() - start;
-		if (LOG.isLoggable(INFO))
-			LOG.info("Deriving key from password took " + duration + " ms");
-		return k;
-	}
-}

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

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

@@ -0,0 +1,90 @@
+package org.briarproject.bramble.crypto;
+
+import org.briarproject.bramble.api.crypto.PrivateKey;
+import org.briarproject.bramble.api.crypto.PublicKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.spongycastle.crypto.Digest;
+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;
+import org.spongycastle.crypto.signers.ECDSASigner;
+import org.spongycastle.crypto.signers.HMacDSAKCalculator;
+
+import java.security.GeneralSecurityException;
+import java.security.SecureRandom;
+import java.util.logging.Logger;
+
+import javax.annotation.concurrent.NotThreadSafe;
+
+import static java.util.logging.Level.INFO;
+
+@NotThreadSafe
+@NotNullByDefault
+class SignatureImpl implements Signature {
+
+	private static final Logger LOG =
+			Logger.getLogger(SignatureImpl.class.getName());
+
+	private final SecureRandom secureRandom;
+	private final DSADigestSigner signer;
+
+	SignatureImpl(SecureRandom secureRandom) {
+		this.secureRandom = secureRandom;
+		Digest digest = new Blake2sDigest();
+		DSAKCalculator calculator = new HMacDSAKCalculator(digest);
+		signer = new DSADigestSigner(new ECDSASigner(calculator), digest);
+	}
+
+	@Override
+	public void initSign(PrivateKey k) throws GeneralSecurityException {
+		if (!(k instanceof Sec1PrivateKey))
+			throw new IllegalArgumentException();
+		ECPrivateKeyParameters priv = ((Sec1PrivateKey) k).getKey();
+		signer.init(true, new ParametersWithRandom(priv, secureRandom));
+	}
+
+	@Override
+	public void initVerify(PublicKey k) throws GeneralSecurityException {
+		if (!(k instanceof Sec1PublicKey))
+			throw new IllegalArgumentException();
+		ECPublicKeyParameters pub = ((Sec1PublicKey) k).getKey();
+		signer.init(false, pub);
+	}
+
+	@Override
+	public void update(byte b) {
+		signer.update(b);
+	}
+
+	@Override
+	public void update(byte[] b) {
+		update(b, 0, b.length);
+	}
+
+	@Override
+	public void update(byte[] b, int off, int len) {
+		signer.update(b, off, len);
+	}
+
+	@Override
+	public byte[] sign() {
+		long now = System.currentTimeMillis();
+		byte[] signature = signer.generateSignature();
+		long duration = System.currentTimeMillis() - now;
+		if (LOG.isLoggable(INFO))
+			LOG.info("Generating signature took " + duration + " ms");
+		return signature;
+	}
+
+	@Override
+	public boolean verify(byte[] signature) {
+		long now = System.currentTimeMillis();
+		boolean valid = signer.verifySignature(signature);
+		long duration = System.currentTimeMillis() - now;
+		if (LOG.isLoggable(INFO))
+			LOG.info("Verifying signature took " + duration + " ms");
+		return valid;
+	}
+}

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

@@ -4,7 +4,6 @@ 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;
 
@@ -23,15 +22,12 @@ 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;
 	}
 
@@ -41,8 +37,7 @@ class StreamEncrypterFactoryImpl implements StreamEncrypterFactory {
 		AuthenticatedCipher cipher = cipherProvider.get();
 		long streamNumber = ctx.getStreamNumber();
 		byte[] tag = new byte[TAG_LENGTH];
-		transportCrypto.encodeTag(tag, ctx.getTagKey(), PROTOCOL_VERSION,
+		crypto.encodeTag(tag, ctx.getTagKey(), PROTOCOL_VERSION, streamNumber);
-				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

@@ -1,136 +0,0 @@
-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 org.spongycastle.crypto.digests.Blake2bDigest;
-
-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 Blake2bDigest(tagKey.getBytes(), 32, null, null);
-		// 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/Database.java

@@ -2,11 +2,8 @@ package org.briarproject.bramble.db;
 
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.db.DataTooNewException;
-import org.briarproject.bramble.api.db.DataTooOldException;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Metadata;
-import org.briarproject.bramble.api.db.MigrationListener;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.identity.LocalAuthor;
@@ -40,13 +37,8 @@ interface Database<T> {
 
 	/**
 	 * Opens the database and returns true if the database already existed.
-	 *
-	 * @throws DataTooNewException if the data uses a newer schema than the
-	 * current code
-	 * @throws DataTooOldException if the data uses an older schema than the
-	 * current code and cannot be migrated
 	 */
-	boolean open(@Nullable MigrationListener listener) throws DbException;
+	boolean open() throws DbException;
 
 	/**
 	 * Prevents new transactions from starting, waits for all current
@@ -97,12 +89,9 @@ interface Database<T> {
 
 	/**
 	 * Stores a message.
-	 *
-	 * @param sender the contact from whom the message was received, or null
-	 * if the message was created locally.
 	 */
-	void addMessage(T txn, Message m, State state, boolean shared,
+	void addMessage(T txn, Message m, State state, boolean shared)
-			@Nullable ContactId sender) throws DbException;
+			throws DbException;
 
 	/**
 	 * Adds a dependency between two messages in the given group.
@@ -115,6 +104,16 @@ interface Database<T> {
 	 */
 	void addOfferedMessage(T txn, ContactId c, MessageId m) throws DbException;
 
+	/**
+	 * Initialises the status of the given message with respect to the given
+	 * contact.
+	 *
+	 * @param ack whether the message needs to be acknowledged.
+	 * @param seen whether the contact has seen the message.
+	 */
+	void addStatus(T txn, ContactId c, MessageId m, boolean ack, boolean seen)
+			throws DbException;
+
 	/**
 	 * Stores a transport.
 	 */
@@ -273,7 +272,7 @@ interface Database<T> {
 	 * <p/>
 	 * Read-only.
 	 */
-	Map<ContactId, Boolean> getGroupVisibility(T txn, GroupId g)
+	Collection<ContactId> getGroupVisibility(T txn, GroupId g)
 			throws DbException;
 
 	/**
@@ -424,37 +423,31 @@ interface Database<T> {
 			throws DbException;
 
 	/**
-	 * Returns the IDs of any messages that need to be validated.
+	 * Returns the IDs of any messages that need to be validated by the given
+	 * client.
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<MessageId> getMessagesToValidate(T txn) throws DbException;
+	Collection<MessageId> getMessagesToValidate(T txn, ClientId c)
+			throws DbException;
 
 	/**
-	 * Returns the IDs of any messages that are pending delivery due to
+	 * Returns the IDs of any messages that are still pending due to
-	 * dependencies on other messages.
+	 * dependencies to other messages for the given client.
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<MessageId> getPendingMessages(T txn) throws DbException;
+	Collection<MessageId> getPendingMessages(T txn, ClientId c)
+			throws DbException;
 
 	/**
-	 * Returns the IDs of any messages that have a shared dependent but have
+	 * Returns the IDs of any messages from the given client
-	 * not yet been shared themselves.
+	 * that have a shared dependent, but are still not shared themselves.
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<MessageId> getMessagesToShare(T txn) throws DbException;
+	Collection<MessageId> getMessagesToShare(T txn, ClientId c)
-
+			throws DbException;
-	/**
-	 * Returns the next time (in milliseconds since the Unix epoch) when a
-	 * message is due to be sent to the given contact. The returned value may
-	 * be zero if a message is due to be sent immediately, or Long.MAX_VALUE
-	 * if no messages are scheduled to be sent.
-	 * <p/>
-	 * Read-only.
-	 */
-	long getNextSendTime(T txn, ContactId c) throws DbException;
 
 	/**
 	 * Returns the message with the given ID, in serialised form, or null if
@@ -573,6 +566,13 @@ interface Database<T> {
 	 */
 	void removeMessage(T txn, MessageId m) throws DbException;
 
+	/**
+	 * Removes an offered message that was offered by the given contact, or
+	 * returns false if there is no such message.
+	 */
+	boolean removeOfferedMessage(T txn, ContactId c, MessageId m)
+			throws DbException;
+
 	/**
 	 * Removes the given offered messages that were offered by the given
 	 * contact.
@@ -580,6 +580,12 @@ interface Database<T> {
 	void removeOfferedMessages(T txn, ContactId c,
 			Collection<MessageId> requested) throws DbException;
 
+	/**
+	 * Removes the status of the given message with respect to the given
+	 * contact.
+	 */
+	void removeStatus(T txn, ContactId c, MessageId m) throws DbException;
+
 	/**
 	 * Removes a transport (and all associated state) from the database.
 	 */

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

@@ -10,7 +10,6 @@ import org.briarproject.bramble.api.db.ContactExistsException;
 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.MigrationListener;
 import org.briarproject.bramble.api.db.NoSuchContactException;
 import org.briarproject.bramble.api.db.NoSuchGroupException;
 import org.briarproject.bramble.api.db.NoSuchLocalAuthorException;
@@ -91,6 +90,8 @@ 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) {
@@ -101,22 +102,23 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public boolean open(@Nullable MigrationListener listener)
+	public boolean open() throws DbException {
-			throws DbException {
+		Runnable shutdownHook = () -> {
-		boolean reopened = db.open(listener);
-		shutdown.addShutdownHook(() -> {
 			try {
 				close();
 			} catch (DbException e) {
 				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			}
-		});
+		};
+		boolean reopened = db.open();
+		shutdownHandle = shutdown.addShutdownHook(shutdownHook);
 		return reopened;
 	}
 
 	@Override
 	public void close() throws DbException {
 		if (closed.getAndSet(true)) return;
+		shutdown.removeShutdownHook(shutdownHandle);
 		db.close();
 	}
 
@@ -215,7 +217,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		if (!db.containsGroup(txn, m.getGroupId()))
 			throw new NoSuchGroupException();
 		if (!db.containsMessage(txn, m.getId())) {
-			db.addMessage(txn, m, DELIVERED, shared, null);
+			addMessage(txn, m, DELIVERED, shared, null);
 			transaction.attach(new MessageAddedEvent(m, null));
 			transaction.attach(new MessageStateChangedEvent(m.getId(), true,
 					DELIVERED));
@@ -224,6 +226,16 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		db.mergeMessageMetadata(txn, m.getId(), meta);
 	}
 
+	private void addMessage(T txn, Message m, State state, boolean shared,
+			@Nullable ContactId sender) throws DbException {
+		db.addMessage(txn, m, state, shared);
+		for (ContactId c : db.getGroupVisibility(txn, m.getGroupId())) {
+			boolean offered = db.removeOfferedMessage(txn, c, m.getId());
+			boolean seen = offered || (sender != null && c.equals(sender));
+			db.addStatus(txn, c, m.getId(), seen, seen);
+		}
+	}
+
 	@Override
 	public void addTransport(Transaction transaction, TransportId t,
 			int maxLatency) throws DbException {
@@ -455,24 +467,24 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public Collection<MessageId> getMessagesToValidate(Transaction transaction)
+	public Collection<MessageId> getMessagesToValidate(Transaction transaction,
-			throws DbException {
+			ClientId c) throws DbException {
 		T txn = unbox(transaction);
-		return db.getMessagesToValidate(txn);
+		return db.getMessagesToValidate(txn, c);
 	}
 
 	@Override
-	public Collection<MessageId> getPendingMessages(Transaction transaction)
+	public Collection<MessageId> getPendingMessages(Transaction transaction,
-			throws DbException {
+			ClientId c) throws DbException {
 		T txn = unbox(transaction);
-		return db.getPendingMessages(txn);
+		return db.getPendingMessages(txn, c);
 	}
 
 	@Override
-	public Collection<MessageId> getMessagesToShare(Transaction transaction)
+	public Collection<MessageId> getMessagesToShare(
-			throws DbException {
+			Transaction transaction, ClientId c) throws DbException {
 		T txn = unbox(transaction);
-		return db.getMessagesToShare(txn);
+		return db.getMessagesToShare(txn, c);
 	}
 
 	@Nullable
@@ -571,13 +583,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.getMessageDependents(txn, m);
 	}
 
-	@Override
-	public long getNextSendTime(Transaction transaction, ContactId c)
-			throws DbException {
-		T txn = unbox(transaction);
-		return db.getNextSendTime(txn, c);
-	}
-
 	@Override
 	public Settings getSettings(Transaction transaction, String namespace)
 			throws DbException {
@@ -672,7 +677,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 				db.raiseSeenFlag(txn, c, m.getId());
 				db.raiseAckFlag(txn, c, m.getId());
 			} else {
-				db.addMessage(txn, m, UNKNOWN, false, c);
+				addMessage(txn, m, UNKNOWN, false, c);
 				transaction.attach(new MessageAddedEvent(m, c));
 			}
 			transaction.attach(new MessageToAckEvent(c));
@@ -740,8 +745,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		GroupId id = g.getId();
 		if (!db.containsGroup(txn, id))
 			throw new NoSuchGroupException();
-		Collection<ContactId> affected =
+		Collection<ContactId> affected = db.getGroupVisibility(txn, id);
-				db.getGroupVisibility(txn, id).keySet();
 		db.removeGroup(txn, id);
 		transaction.attach(new GroupRemovedEvent(g));
 		transaction.attach(new GroupVisibilityUpdatedEvent(affected));
@@ -811,9 +815,19 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			throw new NoSuchGroupException();
 		Visibility old = db.getGroupVisibility(txn, c, g);
 		if (old == v) return;
-		if (old == INVISIBLE) db.addGroupVisibility(txn, c, g, v == SHARED);
+		if (old == INVISIBLE) {
-		else if (v == INVISIBLE) db.removeGroupVisibility(txn, c, g);
+			db.addGroupVisibility(txn, c, g, v == SHARED);
-		else db.setGroupVisibility(txn, c, g, v == SHARED);
+			for (MessageId m : db.getMessageIds(txn, g)) {
+				boolean seen = db.removeOfferedMessage(txn, c, m);
+				db.addStatus(txn, c, m, seen, seen);
+			}
+		} else if (v == INVISIBLE) {
+			db.removeGroupVisibility(txn, c, g);
+			for (MessageId m : db.getMessageIds(txn, g))
+				db.removeStatus(txn, c, m);
+		} else {
+			db.setGroupVisibility(txn, c, g, v == SHARED);
+		}
 		List<ContactId> affected = Collections.singletonList(c);
 		transaction.attach(new GroupVisibilityUpdatedEvent(affected));
 	}

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

@@ -23,4 +23,10 @@ interface DatabaseConstants {
 	 */
 	String SCHEMA_VERSION_KEY = "schemaVersion";
 
+	/**
+	 * The {@link Settings} key under which the minimum supported database
+	 * schema version is stored.
+	 */
+	String MIN_SCHEMA_VERSION_KEY = "minSchemaVersion";
+
 }

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

@@ -3,7 +3,6 @@ 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.db.MigrationListener;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.util.StringUtils;
@@ -14,7 +13,6 @@ import java.sql.DriverManager;
 import java.sql.SQLException;
 import java.util.Properties;
 
-import javax.annotation.Nullable;
 import javax.inject.Inject;
 
 /**
@@ -24,31 +22,28 @@ 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 STRING_TYPE = "VARCHAR";
+	private static final String SECRET_TYPE = "BINARY(32)";
 
 	private final DatabaseConfig config;
 	private final String url;
 
 	@Inject
 	H2Database(DatabaseConfig config, Clock clock) {
-		super(HASH_TYPE, SECRET_TYPE, BINARY_TYPE, COUNTER_TYPE, STRING_TYPE,
+		super(HASH_TYPE, BINARY_TYPE, COUNTER_TYPE, SECRET_TYPE, clock);
-				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";
+				+ ";WRITE_DELAY=0;DB_CLOSE_ON_EXIT=false";
 	}
 
 	@Override
-	public boolean open(@Nullable MigrationListener listener)
+	public boolean open() throws DbException {
-			throws DbException {
 		boolean reopen = config.databaseExists();
 		if (!reopen) config.getDatabaseDirectory().mkdirs();
-		super.open("org.h2.Driver", reopen, listener);
+		super.open("org.h2.Driver", reopen);
 		return reopen;
 	}
 
@@ -95,10 +90,6 @@ class H2Database extends JdbcDatabase {
 		// Separate the file password from the user password with a space
 		String hex = StringUtils.toHexString(key.getBytes());
 		props.put("password", hex + " password");
-		return DriverManager.getConnection(getUrl(), props);
+		return DriverManager.getConnection(url, props);
-	}
-
-	String getUrl() {
-		return url;
 	}
 }

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

@@ -1,101 +0,0 @@
-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.db.MigrationListener;
-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.annotation.Nullable;
-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(@Nullable MigrationListener listener) throws DbException {
-		boolean reopen = config.databaseExists();
-		if (!reopen) config.getDatabaseDirectory().mkdirs();
-		super.open("org.hsqldb.jdbc.JDBCDriver", reopen, listener);
-		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/Migration.java

@@ -1,18 +0,0 @@
-package org.briarproject.bramble.db;
-
-import org.briarproject.bramble.api.db.DbException;
-
-interface Migration<T> {
-
-	/**
-	 * Returns the schema version from which this migration starts.
-	 */
-	int getStartVersion();
-
-	/**
-	 * Returns the schema version at which this migration ends.
-	 */
-	int getEndVersion();
-
-	void migrate(T txn) throws DbException;
-}

bramble-core/src/main/java/org/briarproject/bramble/identity/AuthorFactoryImpl.java

@@ -1,65 +1,61 @@
 package org.briarproject.bramble.identity;
 
 import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.data.BdfWriter;
+import org.briarproject.bramble.api.data.BdfWriterFactory;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorFactory;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.bramble.util.ByteUtils;
+
-import org.briarproject.bramble.util.StringUtils;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
 
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
-import static org.briarproject.bramble.api.identity.Author.FORMAT_VERSION;
-import static org.briarproject.bramble.api.identity.AuthorId.LABEL;
-import static org.briarproject.bramble.util.ByteUtils.INT_32_BYTES;
-
 @Immutable
 @NotNullByDefault
 class AuthorFactoryImpl implements AuthorFactory {
 
 	private final CryptoComponent crypto;
+	private final BdfWriterFactory bdfWriterFactory;
 	private final Clock clock;
 
 	@Inject
-	AuthorFactoryImpl(CryptoComponent crypto, Clock clock) {
+	AuthorFactoryImpl(CryptoComponent crypto, BdfWriterFactory bdfWriterFactory,
+			Clock clock) {
 		this.crypto = crypto;
+		this.bdfWriterFactory = bdfWriterFactory;
 		this.clock = clock;
 	}
 
 	@Override
 	public Author createAuthor(String name, byte[] publicKey) {
-		return createAuthor(FORMAT_VERSION, name, publicKey);
+		return new Author(getId(name, publicKey), name, publicKey);
-	}
-
-	@Override
-	public Author createAuthor(int formatVersion, String name,
-			byte[] publicKey) {
-		AuthorId id = getId(formatVersion, name, publicKey);
-		return new Author(id, formatVersion, name, publicKey);
 	}
 
 	@Override
 	public LocalAuthor createLocalAuthor(String name, byte[] publicKey,
 			byte[] privateKey) {
-		return createLocalAuthor(FORMAT_VERSION, name, publicKey, privateKey);
+		return new LocalAuthor(getId(name, publicKey), name, publicKey,
+				privateKey, clock.currentTimeMillis());
 	}
 
-	@Override
+	private AuthorId getId(String name, byte[] publicKey) {
-	public LocalAuthor createLocalAuthor(int formatVersion, String name,
+		ByteArrayOutputStream out = new ByteArrayOutputStream();
-			byte[] publicKey, byte[] privateKey) {
+		BdfWriter w = bdfWriterFactory.createWriter(out);
-		AuthorId id = getId(formatVersion, name, publicKey);
+		try {
-		return new LocalAuthor(id, formatVersion, name, publicKey, privateKey,
+			w.writeListStart();
-				clock.currentTimeMillis());
+			w.writeString(name);
-	}
+			w.writeRaw(publicKey);
-
+			w.writeListEnd();
-	private AuthorId getId(int formatVersion, String name, byte[] publicKey) {
+		} catch (IOException e) {
-		byte[] formatVersionBytes = new byte[INT_32_BYTES];
+			// Shouldn't happen with ByteArrayOutputStream
-		ByteUtils.writeUint32(formatVersion, formatVersionBytes, 0);
+			throw new RuntimeException(e);
-		return new AuthorId(crypto.hash(LABEL, formatVersionBytes,
+		}
-				StringUtils.toUtf8(name), publicKey));
+		return new AuthorId(crypto.hash(AuthorId.LABEL, out.toByteArray()));
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/identity/AuthorReader.java

@@ -0,0 +1,36 @@
+package org.briarproject.bramble.identity;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.data.BdfReader;
+import org.briarproject.bramble.api.data.ObjectReader;
+import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.identity.AuthorFactory;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.io.IOException;
+
+import javax.annotation.concurrent.Immutable;
+
+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
+
+@Immutable
+@NotNullByDefault
+class AuthorReader implements ObjectReader<Author> {
+
+	private final AuthorFactory authorFactory;
+
+	AuthorReader(AuthorFactory authorFactory) {
+		this.authorFactory = authorFactory;
+	}
+
+	@Override
+	public Author readObject(BdfReader r) throws IOException {
+		r.readListStart();
+		String name = r.readString(MAX_AUTHOR_NAME_LENGTH);
+		if (name.length() == 0) throw new FormatException();
+		byte[] publicKey = r.readRaw(MAX_PUBLIC_KEY_LENGTH);
+		r.readListEnd();
+		return authorFactory.createAuthor(name, publicKey);
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/identity/IdentityModule.java

@@ -1,7 +1,13 @@
 package org.briarproject.bramble.identity;
 
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.data.BdfWriterFactory;
+import org.briarproject.bramble.api.data.ObjectReader;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorFactory;
 import org.briarproject.bramble.api.identity.IdentityManager;
+import org.briarproject.bramble.api.system.Clock;
 
 import javax.inject.Inject;
 import javax.inject.Singleton;
@@ -18,14 +24,19 @@ public class IdentityModule {
 	}
 
 	@Provides
-	AuthorFactory provideAuthorFactory(AuthorFactoryImpl authorFactory) {
+	AuthorFactory provideAuthorFactory(CryptoComponent crypto,
-		return authorFactory;
+			BdfWriterFactory bdfWriterFactory, Clock clock) {
+		return new AuthorFactoryImpl(crypto, bdfWriterFactory, clock);
 	}
 
 	@Provides
 	@Singleton
-	IdentityManager provideIdentityManager(
+	IdentityManager provideIdentityModule(DatabaseComponent db) {
-			IdentityManagerImpl identityManager) {
+		return new IdentityManagerImpl(db);
-		return identityManager;
+	}
+
+	@Provides
+	ObjectReader<Author> provideAuthorReader(AuthorFactory authorFactory) {
+		return new AuthorReader(authorFactory);
 	}
 }

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

@@ -1,36 +0,0 @@
-package org.briarproject.bramble.keyagreement;
-
-import org.briarproject.bramble.api.keyagreement.KeyAgreementConnection;
-
-import java.util.concurrent.Callable;
-
-import javax.annotation.Nullable;
-
-interface ConnectionChooser {
-
-	/**
-	 * Submits a connection task to the chooser.
-	 */
-	void submit(Callable<KeyAgreementConnection> task);
-
-	/**
-	 * Returns a connection returned by any of the tasks submitted to the
-	 * chooser, waiting up to the given amount of time for a connection if
-	 * necessary. Returns null if the time elapses without a connection
-	 * becoming available.
-	 *
-	 * @param timeout the timeout in milliseconds
-	 * @throws InterruptedException if the thread is interrupted while waiting
-	 * for a connection to become available
-	 */
-	@Nullable
-	KeyAgreementConnection poll(long timeout) throws InterruptedException;
-
-	/**
-	 * Stops the chooser. Any connections already returned to the chooser are
-	 * closed unless they have been removed from the chooser by calling
-	 * {@link #poll(long)}. Any connections subsequently returned to the
-	 * chooser will also be closed.
-	 */
-	void stop();
-}

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

@@ -1,112 +0,0 @@
-package org.briarproject.bramble.keyagreement;
-
-import org.briarproject.bramble.api.keyagreement.KeyAgreementConnection;
-import org.briarproject.bramble.api.lifecycle.IoExecutor;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-import org.briarproject.bramble.api.system.Clock;
-
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.LinkedList;
-import java.util.List;
-import java.util.Queue;
-import java.util.concurrent.Callable;
-import java.util.concurrent.Executor;
-import java.util.logging.Logger;
-
-import javax.annotation.Nullable;
-import javax.annotation.concurrent.ThreadSafe;
-import javax.inject.Inject;
-
-import static java.util.logging.Level.INFO;
-
-@NotNullByDefault
-@ThreadSafe
-class ConnectionChooserImpl implements ConnectionChooser {
-
-	private static final Logger LOG =
-			Logger.getLogger(ConnectionChooserImpl.class.getName());
-
-	private final Clock clock;
-	private final Executor ioExecutor;
-	private final Object lock = new Object();
-
-	// The following are locking: lock
-	private boolean stopped = false;
-	private final Queue<KeyAgreementConnection> results = new LinkedList<>();
-
-	@Inject
-	ConnectionChooserImpl(Clock clock, @IoExecutor Executor ioExecutor) {
-		this.clock = clock;
-		this.ioExecutor = ioExecutor;
-	}
-
-	@Override
-	public void submit(Callable<KeyAgreementConnection> task) {
-		ioExecutor.execute(() -> {
-			try {
-				KeyAgreementConnection c = task.call();
-				if (c != null) addResult(c);
-			} catch (Exception e) {
-				if (LOG.isLoggable(INFO)) LOG.info(e.toString());
-			}
-		});
-	}
-
-	@Nullable
-	@Override
-	public KeyAgreementConnection poll(long timeout)
-			throws InterruptedException {
-		long now = clock.currentTimeMillis();
-		long end = now + timeout;
-		synchronized (lock) {
-			while (!stopped && results.isEmpty() && now < end) {
-				lock.wait(end - now);
-				now = clock.currentTimeMillis();
-			}
-			return results.poll();
-		}
-	}
-
-	@Override
-	public void stop() {
-		List<KeyAgreementConnection> unused;
-		synchronized (lock) {
-			unused = new ArrayList<>(results);
-			results.clear();
-			stopped = true;
-			lock.notifyAll();
-		}
-		if (LOG.isLoggable(INFO))
-			LOG.info("Closing " + unused.size() + " unused connections");
-		for (KeyAgreementConnection c : unused) tryToClose(c.getConnection());
-	}
-
-	private void addResult(KeyAgreementConnection c) {
-		if (LOG.isLoggable(INFO))
-			LOG.info("Got connection for " + c.getTransportId());
-		boolean close = false;
-		synchronized (lock) {
-			if (stopped) {
-				close = true;
-			} else {
-				results.add(c);
-				lock.notifyAll();
-			}
-		}
-		if (close) {
-			LOG.info("Already stopped");
-			tryToClose(c.getConnection());
-		}
-	}
-
-	private void tryToClose(DuplexTransportConnection conn) {
-		try {
-			conn.getReader().dispose(false, true);
-			conn.getWriter().dispose(false);
-		} catch (IOException e) {
-			if (LOG.isLoggable(INFO)) LOG.info(e.toString());
-		}
-	}
-}

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.KeyAgreementCrypto;
+import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.KeyPair;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementConnection;
@@ -13,19 +13,23 @@ import org.briarproject.bramble.api.plugin.PluginManager;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.bramble.api.system.Clock;
 
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.Callable;
-import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.CompletionService;
-import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
-import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ExecutorCompletionService;
+import java.util.concurrent.Future;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.CONNECTION_TIMEOUT;
@@ -41,31 +45,33 @@ class KeyAgreementConnector {
 			Logger.getLogger(KeyAgreementConnector.class.getName());
 
 	private final Callbacks callbacks;
-	private final KeyAgreementCrypto keyAgreementCrypto;
+	private final Clock clock;
+	private final CryptoComponent crypto;
 	private final PluginManager pluginManager;
-	private final ConnectionChooser connectionChooser;
+	private final CompletionService<KeyAgreementConnection> connect;
 
-	private final List<KeyAgreementListener> listeners =
+	private final List<KeyAgreementListener> listeners = new ArrayList<>();
-			new CopyOnWriteArrayList<>();
+	private final List<Future<KeyAgreementConnection>> pending =
-	private final CountDownLatch aliceLatch = new CountDownLatch(1);
+			new ArrayList<>();
-	private final AtomicBoolean waitingSent = new AtomicBoolean(false);
 
-	private volatile boolean alice = false, stopped = false;
+	private volatile boolean connecting = false;
+	private volatile boolean alice = false;
 
-	KeyAgreementConnector(Callbacks callbacks,
+	KeyAgreementConnector(Callbacks callbacks, Clock clock,
-			KeyAgreementCrypto keyAgreementCrypto, PluginManager pluginManager,
+			CryptoComponent crypto, PluginManager pluginManager,
-			ConnectionChooser connectionChooser) {
+			Executor ioExecutor) {
 		this.callbacks = callbacks;
-		this.keyAgreementCrypto = keyAgreementCrypto;
+		this.clock = clock;
+		this.crypto = crypto;
 		this.pluginManager = pluginManager;
-		this.connectionChooser = connectionChooser;
+		connect = new ExecutorCompletionService<>(ioExecutor);
 	}
 
-	Payload listen(KeyPair localKeyPair) {
+	public Payload listen(KeyPair localKeyPair) {
 		LOG.info("Starting BQP listeners");
 		// Derive commitment
-		byte[] commitment = keyAgreementCrypto.deriveKeyCommitment(
+		byte[] commitment = crypto.deriveKeyCommitment(
-				localKeyPair.getPublic());
+				localKeyPair.getPublic().getEncoded());
 		// Start all listeners and collect their descriptors
 		List<TransportDescriptor> descriptors = new ArrayList<>();
 		for (DuplexPlugin plugin : pluginManager.getKeyAgreementPlugins()) {
@@ -74,9 +80,8 @@ class KeyAgreementConnector {
 			if (l != null) {
 				TransportId id = plugin.getId();
 				descriptors.add(new TransportDescriptor(id, l.getDescriptor()));
-				if (LOG.isLoggable(INFO)) LOG.info("Listening via " + id);
+				pending.add(connect.submit(new ReadableTask(l.listen())));
 				listeners.add(l);
-				connectionChooser.submit(new ReadableTask(l::accept));
 			}
 		}
 		return new Payload(commitment, descriptors);
@@ -84,92 +89,125 @@ class KeyAgreementConnector {
 
 	void stopListening() {
 		LOG.info("Stopping BQP listeners");
-		stopped = true;
+		for (KeyAgreementListener l : listeners) {
-		aliceLatch.countDown();
+			l.close();
-		for (KeyAgreementListener l : listeners) l.close();
+		}
-		connectionChooser.stop();
+		listeners.clear();
 	}
 
 	@Nullable
-	public KeyAgreementTransport connect(Payload remotePayload, boolean alice) {
+	public KeyAgreementTransport connect(Payload remotePayload,
-		// Let the ReadableTasks know if we are Alice
+			boolean alice) {
+		// Let the listeners know if we are Alice
+		this.connecting = true;
 		this.alice = alice;
-		aliceLatch.countDown();
+		long end = clock.currentTimeMillis() + CONNECTION_TIMEOUT;
 
 		// Start connecting over supported transports
-		if (LOG.isLoggable(INFO)) {
+		LOG.info("Starting outgoing BQP connections");
-			LOG.info("Starting outgoing BQP connections as "
-					+ (alice ? "Alice" : "Bob"));
-		}
 		for (TransportDescriptor d : remotePayload.getTransportDescriptors()) {
 			Plugin p = pluginManager.getPlugin(d.getId());
 			if (p instanceof DuplexPlugin) {
-				if (LOG.isLoggable(INFO))
-					LOG.info("Connecting via " + d.getId());
 				DuplexPlugin plugin = (DuplexPlugin) p;
-				byte[] commitment = remotePayload.getCommitment();
+				pending.add(connect.submit(new ReadableTask(
-				BdfList descriptor = d.getDescriptor();
+						new ConnectorTask(plugin, remotePayload.getCommitment(),
-				connectionChooser.submit(new ReadableTask(
+								d.getDescriptor(), end))));
-						new ConnectorTask(plugin, commitment, descriptor)));
 			}
 		}
 
 		// Get chosen connection
+		KeyAgreementConnection chosen = null;
 		try {
-			KeyAgreementConnection chosen =
+			long now = clock.currentTimeMillis();
-					connectionChooser.poll(CONNECTION_TIMEOUT);
+			Future<KeyAgreementConnection> f =
-			if (chosen == null) return null;
+					connect.poll(end - now, MILLISECONDS);
+			if (f == null)
+				return null; // No task completed within the timeout.
+			chosen = f.get();
 			return new KeyAgreementTransport(chosen);
 		} catch (InterruptedException e) {
 			LOG.info("Interrupted while waiting for connection");
 			Thread.currentThread().interrupt();
 			return null;
-		} catch (IOException e) {
+		} catch (ExecutionException | IOException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			return null;
 		} finally {
 			stopListening();
+			// Close all other connections
+			closePending(chosen);
 		}
 	}
 
-	private void waitingForAlice() {
+	private void closePending(@Nullable KeyAgreementConnection chosen) {
-		if (!waitingSent.getAndSet(true)) callbacks.connectionWaiting();
+		for (Future<KeyAgreementConnection> f : pending) {
+			try {
+				if (f.cancel(true)) {
+					LOG.info("Cancelled task");
+				} else if (!f.isCancelled()) {
+					KeyAgreementConnection c = f.get();
+					if (c != null && c != chosen)
+						tryToClose(c.getConnection(), false);
+				}
+			} catch (InterruptedException e) {
+				LOG.info("Interrupted while closing sockets");
+				Thread.currentThread().interrupt();
+				return;
+			} catch (ExecutionException e) {
+				if (LOG.isLoggable(INFO)) LOG.info(e.toString());
+			}
+		}
+	}
+
+	private void tryToClose(DuplexTransportConnection conn, boolean exception) {
+		try {
+			if (LOG.isLoggable(INFO))
+				LOG.info("Closing connection, exception: " + exception);
+			conn.getReader().dispose(exception, true);
+			conn.getWriter().dispose(exception);
+		} catch (IOException e) {
+			if (LOG.isLoggable(INFO)) LOG.info(e.toString());
+		}
 	}
 
 	private class ConnectorTask implements Callable<KeyAgreementConnection> {
 
 		private final byte[] commitment;
 		private final BdfList descriptor;
+		private final long end;
 		private final DuplexPlugin plugin;
 
 		private ConnectorTask(DuplexPlugin plugin, byte[] commitment,
-				BdfList descriptor) {
+				BdfList descriptor, long end) {
 			this.plugin = plugin;
 			this.commitment = commitment;
 			this.descriptor = descriptor;
+			this.end = end;
 		}
 
-		@Nullable
 		@Override
 		public KeyAgreementConnection call() throws Exception {
-			// Repeat attempts until we connect, get stopped, or get interrupted
+			// Repeat attempts until we connect, get interrupted, or time out
-			while (!stopped) {
+			while (true) {
+				long now = clock.currentTimeMillis();
+				if (now > end) throw new IOException();
 				DuplexTransportConnection conn =
 						plugin.createKeyAgreementConnection(commitment,
-								descriptor);
+								descriptor, end - now);
 				if (conn != null) {
 					if (LOG.isLoggable(INFO))
-						LOG.info(plugin.getId() + ": Outgoing connection");
+						LOG.info(plugin.getId().getString() +
+								": Outgoing connection");
 					return new KeyAgreementConnection(conn, plugin.getId());
 				}
 				// Wait 2s before retry (to circumvent transient failures)
 				Thread.sleep(2000);
 			}
-			return null;
 		}
 	}
 
-	private class ReadableTask implements Callable<KeyAgreementConnection> {
+	private class ReadableTask
+			implements Callable<KeyAgreementConnection> {
 
 		private final Callable<KeyAgreementConnection> connectionTask;
 
@@ -177,23 +215,24 @@ class KeyAgreementConnector {
 			this.connectionTask = connectionTask;
 		}
 
-		@Nullable
 		@Override
 		public KeyAgreementConnection call() throws Exception {
 			KeyAgreementConnection c = connectionTask.call();
-			if (c == null) return null;
-			aliceLatch.await();
-			if (alice || stopped) return c;
-			// Bob waits here for Alice to scan his QR code, determine her
-			// role, and send her key
 			InputStream in = c.getConnection().getReader().getInputStream();
-			while (!stopped && in.available() == 0) {
+			boolean waitingSent = false;
-				if (LOG.isLoggable(INFO))
+			while (!alice && in.available() == 0) {
-					LOG.info(c.getTransportId() + ": Waiting for data");
+				if (!waitingSent && connecting && !alice) {
-				waitingForAlice();
+					// Bob waits here until Alice obtains his payload.
-				Thread.sleep(500);
+					callbacks.connectionWaiting();
+					waitingSent = true;
+				}
+				if (LOG.isLoggable(INFO)) {
+					LOG.info(c.getTransportId().getString() +
+							": Waiting for connection");
+				}
+				Thread.sleep(1000);
 			}
-			if (!stopped && LOG.isLoggable(INFO))
+			if (!alice && LOG.isLoggable(INFO))
 				LOG.info(c.getTransportId().getString() + ": Data available");
 			return c;
 		}

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

@@ -1,10 +1,19 @@
 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.keyagreement.KeyAgreementTask;
+import org.briarproject.bramble.api.event.EventBus;
+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;
@@ -13,9 +22,13 @@ import dagger.Provides;
 public class KeyAgreementModule {
 
 	@Provides
-	KeyAgreementTask provideKeyAgreementTask(
+	@Singleton
-			KeyAgreementTaskImpl keyAgreementTask) {
+	KeyAgreementTaskFactory provideKeyAgreementTaskFactory(Clock clock,
-		return keyAgreementTask;
+			CryptoComponent crypto, EventBus eventBus,
+			@IoExecutor Executor ioExecutor, PayloadEncoder payloadEncoder,
+			PluginManager pluginManager) {
+		return new KeyAgreementTaskFactoryImpl(clock, crypto, eventBus,
+				ioExecutor, payloadEncoder, pluginManager);
 	}
 
 	@Provides
@@ -27,10 +40,4 @@ public class KeyAgreementModule {
 	PayloadParser providePayloadParser(BdfReaderFactory bdfReaderFactory) {
 		return new PayloadParserImpl(bdfReaderFactory);
 	}
-
-	@Provides
-	ConnectionChooser provideConnectionChooser(
-			ConnectionChooserImpl connectionChooser) {
-		return connectionChooser;
-	}
 }

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

@@ -1,10 +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.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;
@@ -14,10 +11,6 @@ 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/>
@@ -64,7 +57,6 @@ 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;
@@ -72,13 +64,11 @@ 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;
@@ -96,11 +86,10 @@ class KeyAgreementProtocol {
 	 */
 	SecretKey perform() throws AbortException, IOException {
 		try {
-			PublicKey theirPublicKey;
+			byte[] theirPublicKey;
 			if (alice) {
 				sendKey();
-				// Alice waits here for Bob to scan her QR code, determine his
+				// Alice waits here until Bob obtains her payload.
-				// role, receive her key and respond with his key
 				callbacks.connectionWaiting();
 				theirPublicKey = receiveKey();
 			} else {
@@ -115,7 +104,7 @@ class KeyAgreementProtocol {
 				receiveConfirm(s, theirPublicKey);
 				sendConfirm(s, theirPublicKey);
 			}
-			return crypto.deriveKey(MASTER_SECRET_LABEL, s);
+			return crypto.deriveMasterSecret(s);
 		} catch (AbortException e) {
 			sendAbort(e.getCause() != null);
 			throw e;
@@ -126,41 +115,27 @@ class KeyAgreementProtocol {
 		transport.sendKey(ourKeyPair.getPublic().getEncoded());
 	}
 
-	private PublicKey receiveKey() throws AbortException {
+	private byte[] receiveKey() throws AbortException {
-		byte[] publicKeyBytes = transport.receiveKey();
+		byte[] publicKey = transport.receiveKey();
 		callbacks.initialRecordReceived();
-		KeyParser keyParser = crypto.getAgreementKeyParser();
+		byte[] expected = crypto.deriveKeyCommitment(publicKey);
-		try {
+		if (!Arrays.equals(expected, theirPayload.getCommitment()))
-			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(PublicKey theirPublicKey)
+	private SecretKey deriveSharedSecret(byte[] theirPublicKey)
 			throws AbortException {
 		try {
-			byte[] ourPublicKeyBytes = ourKeyPair.getPublic().getEncoded();
+			return crypto.deriveSharedSecret(theirPublicKey, ourKeyPair, alice);
-			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, PublicKey theirPublicKey)
+	private void sendConfirm(SecretKey s, byte[] theirPublicKey)
 			throws IOException {
-		byte[] confirm = keyAgreementCrypto.deriveConfirmationRecord(s,
+		byte[] confirm = crypto.deriveConfirmationRecord(s,
 				payloadEncoder.encode(theirPayload),
 				payloadEncoder.encode(ourPayload),
 				theirPublicKey, ourKeyPair,
@@ -168,10 +143,10 @@ class KeyAgreementProtocol {
 		transport.sendConfirm(confirm);
 	}
 
-	private void receiveConfirm(SecretKey s, PublicKey theirPublicKey)
+	private void receiveConfirm(SecretKey s, byte[] theirPublicKey)
 			throws AbortException {
 		byte[] confirm = transport.receiveConfirm();
-		byte[] expected = keyAgreementCrypto.deriveConfirmationRecord(s,
+		byte[] expected = crypto.deriveConfirmationRecord(s,
 				payloadEncoder.encode(theirPayload),
 				payloadEncoder.encode(ourPayload),
 				theirPublicKey, ourKeyPair,

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

@@ -0,0 +1,46 @@
+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

@@ -1,7 +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.crypto.SecretKey;
 import org.briarproject.bramble.api.event.EventBus;
@@ -18,24 +17,24 @@ import org.briarproject.bramble.api.keyagreement.event.KeyAgreementWaitingEvent;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.PluginManager;
+import org.briarproject.bramble.api.system.Clock;
 
 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
 @ParametersNotNullByDefault
-class KeyAgreementTaskImpl extends Thread implements KeyAgreementTask,
+class KeyAgreementTaskImpl extends Thread implements
-		KeyAgreementProtocol.Callbacks, KeyAgreementConnector.Callbacks {
+		KeyAgreementTask, KeyAgreementConnector.Callbacks,
+		KeyAgreementProtocol.Callbacks {
 
 	private static final Logger LOG =
 			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;
@@ -44,18 +43,15 @@ class KeyAgreementTaskImpl extends Thread implements KeyAgreementTask,
 	private Payload localPayload;
 	private Payload remotePayload;
 
-	@Inject
+	KeyAgreementTaskImpl(Clock clock, CryptoComponent crypto,
-	KeyAgreementTaskImpl(CryptoComponent crypto,
+			EventBus eventBus, PayloadEncoder payloadEncoder,
-			KeyAgreementCrypto keyAgreementCrypto, EventBus eventBus,
+			PluginManager pluginManager, Executor ioExecutor) {
-			PayloadEncoder payloadEncoder, PluginManager pluginManager,
-			ConnectionChooser connectionChooser) {
 		this.crypto = crypto;
-		this.keyAgreementCrypto = keyAgreementCrypto;
 		this.eventBus = eventBus;
 		this.payloadEncoder = payloadEncoder;
 		localKeyPair = crypto.generateAgreementKeyPair();
-		connector = new KeyAgreementConnector(this, keyAgreementCrypto,
+		connector = new KeyAgreementConnector(this, clock, crypto,
-				pluginManager, connectionChooser);
+				pluginManager, ioExecutor);
 	}
 
 	@Override
@@ -69,8 +65,10 @@ class KeyAgreementTaskImpl extends Thread implements KeyAgreementTask,
 	@Override
 	public synchronized void stopListening() {
 		if (localPayload != null) {
-			if (remotePayload == null) connector.stopListening();
+			if (remotePayload == null)
-			else interrupt();
+				connector.stopListening();
+			else
+				interrupt();
 		}
 	}
 
@@ -102,8 +100,8 @@ class KeyAgreementTaskImpl extends Thread implements KeyAgreementTask,
 		// Run BQP protocol over the connection
 		LOG.info("Starting BQP protocol");
 		KeyAgreementProtocol protocol = new KeyAgreementProtocol(this, crypto,
-				keyAgreementCrypto, payloadEncoder, transport, remotePayload,
+				payloadEncoder, transport, remotePayload, localPayload,
-				localPayload, localKeyPair, alice);
+				localKeyPair, alice);
 		try {
 			SecretKey master = protocol.perform();
 			KeyAgreementResult result =

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

@@ -29,10 +29,10 @@ class PayloadEncoderImpl implements PayloadEncoder {
 	@Override
 	public byte[] encode(Payload p) {
 		ByteArrayOutputStream out = new ByteArrayOutputStream();
-		out.write(PROTOCOL_VERSION);
 		BdfWriter w = bdfWriterFactory.createWriter(out);
 		try {
 			w.writeListStart(); // Payload start
+			w.writeLong(PROTOCOL_VERSION);
 			w.writeRaw(p.getCommitment());
 			for (TransportDescriptor d : p.getTransportDescriptors())
 				w.writeList(d.getDescriptor());

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

@@ -1,7 +1,6 @@
 package org.briarproject.bramble.keyagreement;
 
 import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.UnsupportedVersionException;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.data.BdfReader;
 import org.briarproject.bramble.api.data.BdfReaderFactory;
@@ -40,22 +39,20 @@ class PayloadParserImpl implements PayloadParser {
 	@Override
 	public Payload parse(byte[] raw) throws IOException {
 		ByteArrayInputStream in = new ByteArrayInputStream(raw);
-		// First byte: the protocol version
-		int protocolVersion = in.read();
-		if (protocolVersion == -1) throw new FormatException();
-		if (protocolVersion != PROTOCOL_VERSION)
-			throw new UnsupportedVersionException();
-		// The rest of the payload is a BDF list with one or more elements
 		BdfReader r = bdfReaderFactory.createReader(in);
+		// The payload is a BDF list with two or more elements
 		BdfList payload = r.readList();
-		if (payload.isEmpty()) throw new FormatException();
+		if (payload.size() < 2) throw new FormatException();
 		if (!r.eof()) throw new FormatException();
-		// First element: the public key commitment
+		// First element: the protocol version
-		byte[] commitment = payload.getRaw(0);
+		long protocolVersion = payload.getLong(0);
+		if (protocolVersion != PROTOCOL_VERSION) throw new FormatException();
+		// Second element: the public key commitment
+		byte[] commitment = payload.getRaw(1);
 		if (commitment.length != COMMIT_LENGTH) throw new FormatException();
 		// Remaining elements: transport descriptors
 		List<TransportDescriptor> recognised = new ArrayList<>();
-		for (int i = 1; i < payload.size(); i++) {
+		for (int i = 2; i < payload.size(); i++) {
 			BdfList descriptor = payload.getList(i);
 			long transportId = descriptor.getLong(0);
 			if (transportId == TRANSPORT_ID_BLUETOOTH) {

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

@@ -2,11 +2,8 @@ package org.briarproject.bramble.lifecycle;
 
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.KeyPair;
-import org.briarproject.bramble.api.db.DataTooNewException;
-import org.briarproject.bramble.api.db.DataTooOldException;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.db.MigrationListener;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.identity.AuthorFactory;
@@ -15,7 +12,7 @@ import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.lifecycle.Service;
 import org.briarproject.bramble.api.lifecycle.ServiceException;
-import org.briarproject.bramble.api.lifecycle.event.LifecycleEvent;
+import org.briarproject.bramble.api.lifecycle.event.ShutdownEvent;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.Client;
 
@@ -32,21 +29,14 @@ import javax.inject.Inject;
 
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.MIGRATING_DATABASE;
-import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.RUNNING;
-import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.STARTING;
-import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.STARTING_SERVICES;
-import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.STOPPING;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.ALREADY_RUNNING;
-import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.DATA_TOO_NEW_ERROR;
-import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.DATA_TOO_OLD_ERROR;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.DB_ERROR;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.SERVICE_ERROR;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.SUCCESS;
 
 @ThreadSafe
 @NotNullByDefault
-class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
+class LifecycleManagerImpl implements LifecycleManager {
 
 	private static final Logger LOG =
 			Logger.getLogger(LifecycleManagerImpl.class.getName());
@@ -64,8 +54,6 @@ class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
 	private final CountDownLatch startupLatch = new CountDownLatch(1);
 	private final CountDownLatch shutdownLatch = new CountDownLatch(1);
 
-	private volatile LifecycleState state = STARTING;
-
 	@Inject
 	LifecycleManagerImpl(DatabaseComponent db, EventBus eventBus,
 			CryptoComponent crypto, AuthorFactory authorFactory,
@@ -131,7 +119,7 @@ class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
 			LOG.info("Starting services");
 			long start = System.currentTimeMillis();
 
-			boolean reopened = db.open(this);
+			boolean reopened = db.open();
 			long duration = System.currentTimeMillis() - start;
 			if (LOG.isLoggable(INFO)) {
 				if (reopened)
@@ -143,10 +131,7 @@ class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
 				registerLocalAuthor(createLocalAuthor(nickname));
 			}
 
-			state = STARTING_SERVICES;
 			dbLatch.countDown();
-			eventBus.broadcast(new LifecycleEvent(STARTING_SERVICES));
-
 			Transaction txn = db.startTransaction(false);
 			try {
 				for (Client c : clients) {
@@ -172,17 +157,8 @@ class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
 							+ " took " + duration + " ms");
 				}
 			}
-
-			state = RUNNING;
 			startupLatch.countDown();
-			eventBus.broadcast(new LifecycleEvent(RUNNING));
 			return SUCCESS;
-		} catch (DataTooOldException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			return DATA_TOO_OLD_ERROR;
-		} catch (DataTooNewException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			return DATA_TOO_NEW_ERROR;
 		} catch (DbException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			return DB_ERROR;
@@ -194,12 +170,6 @@ class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
 		}
 	}
 
-	@Override
-	public void onMigrationRun() {
-		state = MIGRATING_DATABASE;
-		eventBus.broadcast(new LifecycleEvent(MIGRATING_DATABASE));
-	}
-
 	@Override
 	public void stopServices() {
 		try {
@@ -210,8 +180,7 @@ class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
 		}
 		try {
 			LOG.info("Stopping services");
-			state = STOPPING;
+			eventBus.broadcast(new ShutdownEvent());
-			eventBus.broadcast(new LifecycleEvent(STOPPING));
 			for (Service s : services) {
 				long start = System.currentTimeMillis();
 				s.stopService();
@@ -256,8 +225,4 @@ class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
 		shutdownLatch.await();
 	}
 
-	@Override
-	public LifecycleState getLifecycleState() {
-		return state;
-	}
 }

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

@@ -1,6 +1,5 @@
 package org.briarproject.bramble.plugin;
 
-import org.briarproject.bramble.api.Multiset;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
@@ -37,14 +36,14 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 	private final Lock lock = new ReentrantLock();
 
 	// The following are locking: lock
-	private final Map<TransportId, Multiset<ContactId>> connections;
+	private final Map<TransportId, Map<ContactId, Integer>> connections;
-	private final Multiset<ContactId> contactCounts;
+	private final Map<ContactId, Integer> contactCounts;
 
 	@Inject
 	ConnectionRegistryImpl(EventBus eventBus) {
 		this.eventBus = eventBus;
 		connections = new HashMap<>();
-		contactCounts = new Multiset<>();
+		contactCounts = new HashMap<>();
 	}
 
 	@Override
@@ -57,13 +56,21 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 		boolean firstConnection = false;
 		lock.lock();
 		try {
-			Multiset<ContactId> m = connections.get(t);
+			Map<ContactId, Integer> m = connections.get(t);
 			if (m == null) {
-				m = new Multiset<>();
+				m = new HashMap<>();
 				connections.put(t, m);
 			}
-			m.add(c);
+			Integer count = m.get(c);
-			if (contactCounts.add(c) == 1) firstConnection = true;
+			if (count == null) m.put(c, 1);
+			else m.put(c, count + 1);
+			count = contactCounts.get(c);
+			if (count == null) {
+				firstConnection = true;
+				contactCounts.put(c, 1);
+			} else {
+				contactCounts.put(c, count + 1);
+			}
 		} finally {
 			lock.unlock();
 		}
@@ -84,10 +91,23 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 		boolean lastConnection = false;
 		lock.lock();
 		try {
-			Multiset<ContactId> m = connections.get(t);
+			Map<ContactId, Integer> m = connections.get(t);
 			if (m == null) throw new IllegalArgumentException();
-			m.remove(c);
+			Integer count = m.remove(c);
-			if (contactCounts.remove(c) == 0) lastConnection = true;
+			if (count == null) throw new IllegalArgumentException();
+			if (count == 1) {
+				if (m.isEmpty()) connections.remove(t);
+			} else {
+				m.put(c, count - 1);
+			}
+			count = contactCounts.get(c);
+			if (count == null) throw new IllegalArgumentException();
+			if (count == 1) {
+				lastConnection = true;
+				contactCounts.remove(c);
+			} else {
+				contactCounts.put(c, count - 1);
+			}
 		} finally {
 			lock.unlock();
 		}
@@ -102,7 +122,7 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 	public Collection<ContactId> getConnectedContacts(TransportId t) {
 		lock.lock();
 		try {
-			Multiset<ContactId> m = connections.get(t);
+			Map<ContactId, Integer> m = connections.get(t);
 			if (m == null) return Collections.emptyList();
 			List<ContactId> ids = new ArrayList<>(m.keySet());
 			if (LOG.isLoggable(INFO))
@@ -117,8 +137,8 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 	public boolean isConnected(ContactId c, TransportId t) {
 		lock.lock();
 		try {
-			Multiset<ContactId> m = connections.get(t);
+			Map<ContactId, Integer> m = connections.get(t);
-			return m != null && m.contains(c);
+			return m != null && m.containsKey(c);
 		} finally {
 			lock.unlock();
 		}
@@ -128,7 +148,7 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 	public boolean isConnected(ContactId c) {
 		lock.lock();
 		try {
-			return contactCounts.contains(c);
+			return contactCounts.containsKey(c);
 		} finally {
 			lock.unlock();
 		}

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

@@ -16,7 +16,6 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
 import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
-import org.briarproject.bramble.api.plugin.event.TransportDisabledEvent;
 import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
 import org.briarproject.bramble.api.system.Clock;
@@ -26,7 +25,6 @@ import java.security.SecureRandom;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.Executor;
-import java.util.concurrent.Future;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
@@ -52,7 +50,7 @@ class Poller implements EventListener {
 	private final SecureRandom random;
 	private final Clock clock;
 	private final Lock lock;
-	private final Map<TransportId, ScheduledPollTask> tasks; // Locking: lock
+	private final Map<TransportId, PollTask> tasks; // Locking: lock
 
 	@Inject
 	Poller(@IoExecutor Executor ioExecutor,
@@ -95,10 +93,6 @@ class Poller implements EventListener {
 			TransportEnabledEvent t = (TransportEnabledEvent) e;
 			// Poll the newly enabled transport
 			pollNow(t.getTransportId());
-		} else if (e instanceof TransportDisabledEvent) {
-			TransportDisabledEvent t = (TransportDisabledEvent) e;
-			// Cancel polling for the disabled transport
-			cancel(t.getTransportId());
 		}
 	}
 
@@ -157,31 +151,18 @@ class Poller implements EventListener {
 		TransportId t = p.getId();
 		lock.lock();
 		try {
-			ScheduledPollTask scheduled = tasks.get(t);
+			PollTask scheduled = tasks.get(t);
-			if (scheduled == null || due < scheduled.task.due) {
+			if (scheduled == null || due < scheduled.due) {
-				// If a later task exists, cancel it. If it's already started
-				// it will abort safely when it finds it's been replaced
-				if (scheduled != null) scheduled.future.cancel(false);
 				PollTask task = new PollTask(p, due, randomiseNext);
-				Future future = scheduler.schedule(
+				tasks.put(t, task);
+				scheduler.schedule(
 						() -> ioExecutor.execute(task), delay, MILLISECONDS);
-				tasks.put(t, new ScheduledPollTask(task, future));
 			}
 		} finally {
 			lock.unlock();
 		}
 	}
 
-	private void cancel(TransportId t) {
-		lock.lock();
-		try {
-			ScheduledPollTask scheduled = tasks.remove(t);
-			if (scheduled != null) scheduled.future.cancel(false);
-		} finally {
-			lock.unlock();
-		}
-	}
-
 	@IoExecutor
 	private void poll(Plugin p) {
 		TransportId t = p.getId();
@@ -189,17 +170,6 @@ class Poller implements EventListener {
 		p.poll(connectionRegistry.getConnectedContacts(t));
 	}
 
-	private class ScheduledPollTask {
-
-		private final PollTask task;
-		private final Future future;
-
-		private ScheduledPollTask(PollTask task, Future future) {
-			this.task = task;
-			this.future = future;
-		}
-	}
-
 	private class PollTask implements Runnable {
 
 		private final Plugin plugin;
@@ -218,9 +188,7 @@ class Poller implements EventListener {
 			lock.lock();
 			try {
 				TransportId t = plugin.getId();
-				ScheduledPollTask scheduled = tasks.get(t);
+				if (tasks.get(t) != this) return; // Replaced by another task
-				if (scheduled != null && scheduled.task != this)
-					return; // Replaced by another task
 				tasks.remove(t);
 			} finally {
 				lock.unlock();

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

@@ -23,8 +23,9 @@ import java.net.SocketAddress;
 import java.net.UnknownHostException;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.Comparator;
+import java.util.LinkedList;
 import java.util.List;
+import java.util.concurrent.Callable;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
@@ -43,9 +44,6 @@ class LanTcpPlugin extends TcpPlugin {
 	private static final Logger LOG =
 			Logger.getLogger(LanTcpPlugin.class.getName());
 
-	private static final LanAddressComparator ADDRESS_COMPARATOR =
-			new LanAddressComparator();
-
 	private static final int MAX_ADDRESSES = 4;
 	private static final String SEPARATOR = ",";
 
@@ -65,18 +63,19 @@ class LanTcpPlugin extends TcpPlugin {
 		TransportProperties p = callback.getLocalProperties();
 		String oldIpPorts = p.get(PROP_IP_PORTS);
 		List<InetSocketAddress> olds = parseSocketAddresses(oldIpPorts);
-		List<InetSocketAddress> locals = new ArrayList<>();
+		List<InetSocketAddress> locals = new LinkedList<>();
 		for (InetAddress local : getLocalIpAddresses()) {
 			if (isAcceptableAddress(local)) {
 				// If this is the old address, try to use the same port
 				for (InetSocketAddress old : olds) {
-					if (old.getAddress().equals(local))
+					if (old.getAddress().equals(local)) {
-						locals.add(new InetSocketAddress(local, old.getPort()));
+						int port = old.getPort();
+						locals.add(0, new InetSocketAddress(local, port));
+					}
 				}
 				locals.add(new InetSocketAddress(local, 0));
 			}
 		}
-		Collections.sort(locals, ADDRESS_COMPARATOR);
 		return locals;
 	}
 
@@ -154,39 +153,17 @@ class LanTcpPlugin extends TcpPlugin {
 	// Package access for testing
 	boolean addressesAreOnSameLan(byte[] localIp, byte[] remoteIp) {
 		// 10.0.0.0/8
-		if (isPrefix10(localIp)) return isPrefix10(remoteIp);
+		if (localIp[0] == 10) return remoteIp[0] == 10;
 		// 172.16.0.0/12
-		if (isPrefix172(localIp)) return isPrefix172(remoteIp);
+		if (localIp[0] == (byte) 172 && (localIp[1] & 0xF0) == 16)
+			return remoteIp[0] == (byte) 172 && (remoteIp[1] & 0xF0) == 16;
 		// 192.168.0.0/16
-		if (isPrefix192(localIp)) return isPrefix192(remoteIp);
+		if (localIp[0] == (byte) 192 && localIp[1] == (byte) 168)
+			return remoteIp[0] == (byte) 192 && remoteIp[1] == (byte) 168;
 		// Unrecognised prefix - may be compatible
 		return true;
 	}
 
-	private static boolean isPrefix10(byte[] ipv4) {
-		return ipv4[0] == 10;
-	}
-
-	private static boolean isPrefix172(byte[] ipv4) {
-		return ipv4[0] == (byte) 172 && (ipv4[1] & 0xF0) == 16;
-	}
-
-	private static boolean isPrefix192(byte[] ipv4) {
-		return ipv4[0] == (byte) 192 && ipv4[1] == (byte) 168;
-	}
-
-	// Returns the prefix length for an RFC 1918 address, or 0 for any other
-	// address
-	private static int getRfc1918PrefixLength(InetAddress addr) {
-		if (!(addr instanceof Inet4Address)) return 0;
-		if (!addr.isSiteLocalAddress()) return 0;
-		byte[] ipv4 = addr.getAddress();
-		if (isPrefix10(ipv4)) return 8;
-		if (isPrefix172(ipv4)) return 12;
-		if (isPrefix192(ipv4)) return 16;
-		return 0;
-	}
-
 	@Override
 	public boolean supportsKeyAgreement() {
 		return true;
@@ -223,7 +200,7 @@ class LanTcpPlugin extends TcpPlugin {
 
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
-			byte[] commitment, BdfList descriptor) {
+			byte[] commitment, BdfList descriptor, long timeout) {
 		if (!isRunning()) return null;
 		InetSocketAddress remote;
 		try {
@@ -282,11 +259,14 @@ class LanTcpPlugin extends TcpPlugin {
 		}
 
 		@Override
-		public KeyAgreementConnection accept() throws IOException {
+		public Callable<KeyAgreementConnection> listen() {
-			Socket s = ss.accept();
+			return () -> {
-			if (LOG.isLoggable(INFO)) LOG.info(ID + ": Incoming connection");
+				Socket s = ss.accept();
-			return new KeyAgreementConnection(new TcpTransportConnection(
+				if (LOG.isLoggable(INFO))
-					LanTcpPlugin.this, s), ID);
+					LOG.info(ID.getString() + ": Incoming connection");
+				return new KeyAgreementConnection(
+						new TcpTransportConnection(LanTcpPlugin.this, s), ID);
+			};
 		}
 
 		@Override
@@ -298,19 +278,4 @@ class LanTcpPlugin extends TcpPlugin {
 			}
 		}
 	}
-
-	static class LanAddressComparator implements Comparator<InetSocketAddress> {
-
-		@Override
-		public int compare(InetSocketAddress a, InetSocketAddress b) {
-			// Prefer addresses with non-zero ports
-			int aPort = a.getPort(), bPort = b.getPort();
-			if (aPort > 0 && bPort == 0) return -1;
-			if (aPort == 0 && bPort > 0) return 1;
-			// Prefer addresses with longer RFC 1918 prefixes
-			int aPrefix = getRfc1918PrefixLength(a.getAddress());
-			int bPrefix = getRfc1918PrefixLength(b.getAddress());
-			return bPrefix - aPrefix;
-		}
-	}
 }

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

@@ -297,7 +297,7 @@ abstract class TcpPlugin implements DuplexPlugin {
 
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
-			byte[] commitment, BdfList descriptor) {
+			byte[] commitment, BdfList descriptor, long timeout) {
 		throw new UnsupportedOperationException();
 	}
 

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

@@ -58,13 +58,11 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 		this.metadataParser = metadataParser;
 		this.contactGroupFactory = contactGroupFactory;
 		this.clock = clock;
-		localGroup = contactGroupFactory.createLocalGroup(CLIENT_ID,
+		localGroup = contactGroupFactory.createLocalGroup(CLIENT_ID);
-				CLIENT_VERSION);
 	}
 
 	@Override
 	public void createLocalState(Transaction txn) throws DbException {
-		if (db.containsGroup(txn, localGroup.getId())) return;
 		db.addGroup(txn, localGroup);
 		// Ensure we've set things up for any pre-existing contacts
 		for (Contact c : db.getContacts(txn)) addingContact(txn, c);
@@ -131,7 +129,8 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	public Map<TransportId, TransportProperties> getLocalProperties()
 			throws DbException {
 		Map<TransportId, TransportProperties> local;
-		Transaction txn = db.startTransaction(true);
+		// TODO: Transaction can be read-only when code is simplified
+		Transaction txn = db.startTransaction(false);
 		try {
 			local = getLocalProperties(txn);
 			db.commitTransaction(txn);
@@ -166,7 +165,8 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 			throws DbException {
 		try {
 			TransportProperties p = null;
-			Transaction txn = db.startTransaction(true);
+			// TODO: Transaction can be read-only when code is simplified
+			Transaction txn = db.startTransaction(false);
 			try {
 				// Find the latest local update
 				LatestUpdate latest = findLatest(txn, localGroup.getId(), t,
@@ -192,7 +192,8 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	public Map<ContactId, TransportProperties> getRemoteProperties(
 			TransportId t) throws DbException {
 		Map<ContactId, TransportProperties> remote = new HashMap<>();
-		Transaction txn = db.startTransaction(true);
+		// TODO: Transaction can be read-only when code is simplified
+		Transaction txn = db.startTransaction(false);
 		try {
 			for (Contact c : db.getContacts(txn))
 				remote.put(c.getId(), getRemoteProperties(txn, c, t));
@@ -226,7 +227,8 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	public TransportProperties getRemoteProperties(ContactId c, TransportId t)
 			throws DbException {
 		TransportProperties p;
-		Transaction txn = db.startTransaction(true);
+		// TODO: Transaction can be read-only when code is simplified
+		Transaction txn = db.startTransaction(false);
 		try {
 			p = getRemoteProperties(txn, db.getContact(txn, c), t);
 			db.commitTransaction(txn);
@@ -289,8 +291,7 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	}
 
 	private Group getContactGroup(Contact c) {
-		return contactGroupFactory.createContactGroup(CLIENT_ID,
+		return contactGroupFactory.createContactGroup(CLIENT_ID, c);
-				CLIENT_VERSION, c);
 	}
 
 	private void storeMessage(Transaction txn, GroupId g, TransportId t,
@@ -317,6 +318,7 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 
 	private Map<TransportId, LatestUpdate> findLatestLocal(Transaction txn)
 			throws DbException, FormatException {
+		// TODO: This can be simplified before 1.0
 		Map<TransportId, LatestUpdate> latestUpdates = new HashMap<>();
 		Map<MessageId, BdfDictionary> metadata = clientHelper
 				.getMessageMetadataAsDictionary(txn, localGroup.getId());
@@ -324,7 +326,17 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 			BdfDictionary meta = e.getValue();
 			TransportId t = new TransportId(meta.getString("transportId"));
 			long version = meta.getLong("version");
-			latestUpdates.put(t, new LatestUpdate(e.getKey(), version));
+			LatestUpdate latest = latestUpdates.get(t);
+			if (latest == null) {
+				latestUpdates.put(t, new LatestUpdate(e.getKey(), version));
+			} else if (version > latest.version) {
+				// This update is newer - delete the previous one
+				db.removeMessage(txn, latest.messageId);
+				latestUpdates.put(t, new LatestUpdate(e.getKey(), version));
+			} else {
+				// We've already found a newer update - delete this one
+				db.removeMessage(txn, e.getKey());
+			}
 		}
 		return latestUpdates;
 	}
@@ -332,16 +344,38 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	@Nullable
 	private LatestUpdate findLatest(Transaction txn, GroupId g, TransportId t,
 			boolean local) throws DbException, FormatException {
+		// TODO: This can be simplified before 1.0
+		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) {
-				return new LatestUpdate(e.getKey(), meta.getLong("version"));
+				long version = meta.getLong("version");
+				if (latest == null) {
+					latest = new LatestUpdate(e.getKey(), version);
+				} else if (version > latest.version) {
+					// This update is newer - delete the previous one
+					if (local) {
+						db.removeMessage(txn, latest.messageId);
+					} else {
+						db.deleteMessage(txn, latest.messageId);
+						db.deleteMessageMetadata(txn, latest.messageId);
+					}
+					latest = new LatestUpdate(e.getKey(), version);
+				} else {
+					// We've already found a newer update - delete this one
+					if (local) {
+						db.removeMessage(txn, e.getKey());
+					} else {
+						db.deleteMessage(txn, e.getKey());
+						db.deleteMessageMetadata(txn, e.getKey());
+					}
+				}
 			}
 		}
-		return null;
+		return latest;
 	}
 
 	private TransportProperties parseProperties(BdfList message)

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

@@ -10,7 +10,7 @@ import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
-import org.briarproject.bramble.api.lifecycle.event.LifecycleEvent;
+import org.briarproject.bramble.api.lifecycle.event.ShutdownEvent;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.Ack;
 import org.briarproject.bramble.api.sync.Offer;
@@ -29,8 +29,6 @@ import java.util.Collection;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.Executor;
 import java.util.concurrent.LinkedBlockingQueue;
-import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicLong;
 import java.util.logging.Logger;
 
 import javax.annotation.concurrent.ThreadSafe;
@@ -38,7 +36,6 @@ import javax.annotation.concurrent.ThreadSafe;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.STOPPING;
 import static org.briarproject.bramble.api.sync.SyncConstants.MAX_MESSAGE_IDS;
 import static org.briarproject.bramble.api.sync.SyncConstants.MAX_RECORD_PAYLOAD_LENGTH;
 
@@ -52,14 +49,12 @@ import static org.briarproject.bramble.api.sync.SyncConstants.MAX_RECORD_PAYLOAD
 @NotNullByDefault
 class DuplexOutgoingSession implements SyncSession, EventListener {
 
+	// Check for retransmittable records once every 60 seconds
+	private static final int RETX_QUERY_INTERVAL = 60 * 1000;
 	private static final Logger LOG =
 			Logger.getLogger(DuplexOutgoingSession.class.getName());
 
-	private static final ThrowingRunnable<IOException> CLOSE = () -> {
+	private static final ThrowingRunnable<IOException> CLOSE = () -> {};
-	};
-	private static final ThrowingRunnable<IOException>
-			NEXT_SEND_TIME_DECREASED = () -> {
-	};
 
 	private final DatabaseComponent db;
 	private final Executor dbExecutor;
@@ -70,13 +65,6 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 	private final RecordWriter recordWriter;
 	private final BlockingQueue<ThrowingRunnable<IOException>> writerTasks;
 
-	private final AtomicBoolean generateAckQueued = new AtomicBoolean(false);
-	private final AtomicBoolean generateBatchQueued = new AtomicBoolean(false);
-	private final AtomicBoolean generateOfferQueued = new AtomicBoolean(false);
-	private final AtomicBoolean generateRequestQueued =
-			new AtomicBoolean(false);
-	private final AtomicLong nextSendTime = new AtomicLong(Long.MAX_VALUE);
-
 	private volatile boolean interrupted = false;
 
 	DuplexOutgoingSession(DatabaseComponent db, Executor dbExecutor,
@@ -99,21 +87,21 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		eventBus.addListener(this);
 		try {
 			// Start a query for each type of record
-			generateAck();
+			dbExecutor.execute(new GenerateAck());
-			generateBatch();
+			dbExecutor.execute(new GenerateBatch());
-			generateOffer();
+			dbExecutor.execute(new GenerateOffer());
-			generateRequest();
+			dbExecutor.execute(new GenerateRequest());
 			long now = clock.currentTimeMillis();
 			long nextKeepalive = now + maxIdleTime;
+			long nextRetxQuery = now + RETX_QUERY_INTERVAL;
 			boolean dataToFlush = true;
 			// Write records until interrupted
 			try {
 				while (!interrupted) {
 					// Work out how long we should wait for a record
 					now = clock.currentTimeMillis();
-					long keepaliveWait = Math.max(0, nextKeepalive - now);
+					long wait = Math.min(nextKeepalive, nextRetxQuery) - now;
-					long sendWait = Math.max(0, nextSendTime.get() - now);
+					if (wait < 0) wait = 0;
-					long wait = Math.min(keepaliveWait, sendWait);
 					// Flush any unflushed data if we're going to wait
 					if (wait > 0 && dataToFlush && writerTasks.isEmpty()) {
 						recordWriter.flush();
@@ -125,25 +113,20 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 							MILLISECONDS);
 					if (task == null) {
 						now = clock.currentTimeMillis();
-						if (now >= nextSendTime.get()) {
+						if (now >= nextRetxQuery) {
-							// Check for retransmittable messages
+							// Check for retransmittable records
-							LOG.info("Checking for retransmittable messages");
+							dbExecutor.execute(new GenerateBatch());
-							setNextSendTime(Long.MAX_VALUE);
+							dbExecutor.execute(new GenerateOffer());
-							generateBatch();
+							nextRetxQuery = now + RETX_QUERY_INTERVAL;
-							generateOffer();
 						}
 						if (now >= nextKeepalive) {
 							// Flush the stream to keep it alive
-							LOG.info("Sending keepalive");
 							recordWriter.flush();
 							dataToFlush = false;
 							nextKeepalive = now + maxIdleTime;
 						}
 					} else if (task == CLOSE) {
-						LOG.info("Closed");
 						break;
-					} else if (task == NEXT_SEND_TIME_DECREASED) {
-						LOG.info("Next send time decreased");
 					} else {
 						task.run();
 						dataToFlush = true;
@@ -159,31 +142,6 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		}
 	}
 
-	private void generateAck() {
-		if (generateAckQueued.compareAndSet(false, true))
-			dbExecutor.execute(new GenerateAck());
-	}
-
-	private void generateBatch() {
-		if (generateBatchQueued.compareAndSet(false, true))
-			dbExecutor.execute(new GenerateBatch());
-	}
-
-	private void generateOffer() {
-		if (generateOfferQueued.compareAndSet(false, true))
-			dbExecutor.execute(new GenerateOffer());
-	}
-
-	private void generateRequest() {
-		if (generateRequestQueued.compareAndSet(false, true))
-			dbExecutor.execute(new GenerateRequest());
-	}
-
-	private void setNextSendTime(long time) {
-		long old = nextSendTime.getAndSet(time);
-		if (time < old) writerTasks.add(NEXT_SEND_TIME_DECREASED);
-	}
-
 	@Override
 	public void interrupt() {
 		interrupted = true;
@@ -196,23 +154,22 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			ContactRemovedEvent c = (ContactRemovedEvent) e;
 			if (c.getContactId().equals(contactId)) interrupt();
 		} else if (e instanceof MessageSharedEvent) {
-			generateOffer();
+			dbExecutor.execute(new GenerateOffer());
 		} else if (e instanceof GroupVisibilityUpdatedEvent) {
 			GroupVisibilityUpdatedEvent g = (GroupVisibilityUpdatedEvent) e;
 			if (g.getAffectedContacts().contains(contactId))
-				generateOffer();
+				dbExecutor.execute(new GenerateOffer());
 		} else if (e instanceof MessageRequestedEvent) {
 			if (((MessageRequestedEvent) e).getContactId().equals(contactId))
-				generateBatch();
+				dbExecutor.execute(new GenerateBatch());
 		} else if (e instanceof MessageToAckEvent) {
 			if (((MessageToAckEvent) e).getContactId().equals(contactId))
-				generateAck();
+				dbExecutor.execute(new GenerateAck());
 		} else if (e instanceof MessageToRequestEvent) {
 			if (((MessageToRequestEvent) e).getContactId().equals(contactId))
-				generateRequest();
+				dbExecutor.execute(new GenerateRequest());
-		} else if (e instanceof LifecycleEvent) {
+		} else if (e instanceof ShutdownEvent) {
-			LifecycleEvent l = (LifecycleEvent) e;
+			interrupt();
-			if (l.getLifecycleState() == STOPPING) interrupt();
 		}
 	}
 
@@ -222,7 +179,6 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		@Override
 		public void run() {
 			if (interrupted) return;
-			if (!generateAckQueued.getAndSet(false)) throw new AssertionError();
 			try {
 				Ack a;
 				Transaction txn = db.startTransaction(false);
@@ -256,7 +212,7 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			if (interrupted) return;
 			recordWriter.writeAck(ack);
 			LOG.info("Sent ack");
-			generateAck();
+			dbExecutor.execute(new GenerateAck());
 		}
 	}
 
@@ -266,15 +222,12 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		@Override
 		public void run() {
 			if (interrupted) return;
-			if (!generateBatchQueued.getAndSet(false))
-				throw new AssertionError();
 			try {
 				Collection<byte[]> b;
 				Transaction txn = db.startTransaction(false);
 				try {
 					b = db.generateRequestedBatch(txn, contactId,
 							MAX_RECORD_PAYLOAD_LENGTH, maxLatency);
-					setNextSendTime(db.getNextSendTime(txn, contactId));
 					db.commitTransaction(txn);
 				} finally {
 					db.endTransaction(txn);
@@ -303,7 +256,7 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			if (interrupted) return;
 			for (byte[] raw : batch) recordWriter.writeMessage(raw);
 			LOG.info("Sent batch");
-			generateBatch();
+			dbExecutor.execute(new GenerateBatch());
 		}
 	}
 
@@ -313,15 +266,12 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		@Override
 		public void run() {
 			if (interrupted) return;
-			if (!generateOfferQueued.getAndSet(false))
-				throw new AssertionError();
 			try {
 				Offer o;
 				Transaction txn = db.startTransaction(false);
 				try {
 					o = db.generateOffer(txn, contactId, MAX_MESSAGE_IDS,
 							maxLatency);
-					setNextSendTime(db.getNextSendTime(txn, contactId));
 					db.commitTransaction(txn);
 				} finally {
 					db.endTransaction(txn);
@@ -350,7 +300,7 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			if (interrupted) return;
 			recordWriter.writeOffer(offer);
 			LOG.info("Sent offer");
-			generateOffer();
+			dbExecutor.execute(new GenerateOffer());
 		}
 	}
 
@@ -360,8 +310,6 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		@Override
 		public void run() {
 			if (interrupted) return;
-			if (!generateRequestQueued.getAndSet(false))
-				throw new AssertionError();
 			try {
 				Request r;
 				Transaction txn = db.startTransaction(false);
@@ -395,7 +343,7 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			if (interrupted) return;
 			recordWriter.writeRequest(request);
 			LOG.info("Sent request");
-			generateRequest();
+			dbExecutor.execute(new GenerateRequest());
 		}
 	}
 }

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

@@ -6,16 +6,11 @@ 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 {
@@ -28,12 +23,9 @@ class GroupFactoryImpl implements GroupFactory {
 	}
 
 	@Override
-	public Group createGroup(ClientId c, int clientVersion, byte[] descriptor) {
+	public Group createGroup(ClientId c, byte[] descriptor) {
-		byte[] clientVersionBytes = new byte[INT_32_BYTES];
+		byte[] hash = crypto.hash(GroupId.LABEL,
-		ByteUtils.writeUint32(clientVersion, clientVersionBytes, 0);
+				StringUtils.toUtf8(c.getString()), descriptor);
-		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/IncomingSession.java

@@ -11,7 +11,7 @@ import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
-import org.briarproject.bramble.api.lifecycle.event.LifecycleEvent;
+import org.briarproject.bramble.api.lifecycle.event.ShutdownEvent;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.Ack;
 import org.briarproject.bramble.api.sync.Message;
@@ -27,7 +27,6 @@ import java.util.logging.Logger;
 import javax.annotation.concurrent.ThreadSafe;
 
 import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.STOPPING;
 
 /**
  * An incoming {@link SyncSession}.
@@ -97,9 +96,8 @@ class IncomingSession implements SyncSession, EventListener {
 		if (e instanceof ContactRemovedEvent) {
 			ContactRemovedEvent c = (ContactRemovedEvent) e;
 			if (c.getContactId().equals(contactId)) interrupt();
-		} else if (e instanceof LifecycleEvent) {
+		} else if (e instanceof ShutdownEvent) {
-			LifecycleEvent l = (LifecycleEvent) e;
+			interrupt();
-			if (l.getLifecycleState() == STOPPING) interrupt();
 		}
 	}