Bump version numbers for beta release.

Backport: Enable LAN plugin when providing a wifi access point

See merge request akwizgran/briar!755

.gitignore

@@ -9,15 +9,18 @@ Thumbs.db
 .DS_Store
 
 # Eclipse project files
-#.classpath
-#.project
+.classpath
+.project
+.settings
 
 # Local configuration file (sdk path, etc)
 local.properties
 
 # Android Studio
 .idea/*
+!.idea/runConfigurations/
 !.idea/codeStyleSettings.xml
 .gradle
 build/
 *.iml
+projectFilesBackup/

.gitlab-ci.yml

@@ -0,0 +1,29 @@
+image: registry.gitlab.com/fdroid/ci-images-base:latest
+
+cache:
+  paths:
+    - .gradle/wrapper
+    - .gradle/caches
+
+before_script:
+  - set -e
+  - export GRADLE_USER_HOME=$PWD/.gradle
+  # Accept the license for the Android build tools
+  - echo y | /opt/android-sdk/tools/bin/sdkmanager "build-tools;26.0.2"
+  # Download OpenJDK 6 so we can compile against its standard library
+  - JDK_FILE=openjdk-6-jre-headless_6b38-1.13.10-1~deb7u1_amd64.deb
+  - if [ ! -d openjdk ]
+  - then
+  - wget -q http://ftp.uk.debian.org/debian/pool/main/o/openjdk-6/$JDK_FILE
+  - dpkg-deb -x $JDK_FILE openjdk
+  - fi
+  - export JAVA_6_HOME=$PWD/openjdk/usr/lib/jvm/java-6-openjdk-amd64
+
+test:
+  script:
+    - ./gradlew test
+
+after_script:
+    # this file changes every time but should not be cached
+    - rm -f $GRADLE_USER_HOME/caches/modules-2/modules-2.lock
+    - rm -fr $GRADLE_USER_HOME/caches/*/plugin-resolution/

.idea/runConfigurations/All_tests.xml

@@ -0,0 +1,28 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests" type="AndroidJUnit" factoryName="Android JUnit">
+    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
+    <module name="briar-android" />
+    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
+    <option name="ALTERNATIVE_JRE_PATH" />
+    <option name="PACKAGE_NAME" value="" />
+    <option name="MAIN_CLASS_NAME" value="" />
+    <option name="METHOD_NAME" value="" />
+    <option name="TEST_OBJECT" value="package" />
+    <option name="VM_PARAMETERS" value="-ea" />
+    <option name="PARAMETERS" value="" />
+    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/briar-android" />
+    <option name="ENV_VARIABLES" />
+    <option name="PASS_PARENT_ENVS" value="true" />
+    <option name="TEST_SEARCH_SCOPE">
+      <value defaultName="singleModule" />
+    </option>
+    <envs />
+    <patterns />
+    <method>
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in bramble-api" run_configuration_type="AndroidJUnit" />
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in bramble-core" run_configuration_type="AndroidJUnit" />
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in bramble-j2se" run_configuration_type="AndroidJUnit" />
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in briar-core" run_configuration_type="AndroidJUnit" />
+    </method>
+  </configuration>
+</component>

.idea/runConfigurations/All_tests_in_bramble_api.xml

@@ -0,0 +1,23 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests in bramble-api" type="AndroidJUnit" factoryName="Android JUnit">
+    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
+    <module name="bramble-api" />
+    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
+    <option name="ALTERNATIVE_JRE_PATH" />
+    <option name="PACKAGE_NAME" value="" />
+    <option name="MAIN_CLASS_NAME" value="" />
+    <option name="METHOD_NAME" value="" />
+    <option name="TEST_OBJECT" value="package" />
+    <option name="VM_PARAMETERS" value="-ea" />
+    <option name="PARAMETERS" value="" />
+    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/bramble-api" />
+    <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/All_tests_in_bramble_core.xml

@@ -0,0 +1,23 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests in bramble-core" 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="" />
+    <option name="MAIN_CLASS_NAME" value="" />
+    <option name="METHOD_NAME" value="" />
+    <option name="TEST_OBJECT" value="package" />
+    <option name="VM_PARAMETERS" value="-ea" />
+    <option name="PARAMETERS" value="" />
+    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/bramble-core" />
+    <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/All_tests_in_bramble_j2se.xml

@@ -0,0 +1,23 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests in bramble-j2se" type="AndroidJUnit" factoryName="Android JUnit">
+    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
+    <module name="bramble-j2se" />
+    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
+    <option name="ALTERNATIVE_JRE_PATH" />
+    <option name="PACKAGE_NAME" value="" />
+    <option name="MAIN_CLASS_NAME" value="" />
+    <option name="METHOD_NAME" value="" />
+    <option name="TEST_OBJECT" value="package" />
+    <option name="VM_PARAMETERS" value="-ea -Djava.library.path=libs" />
+    <option name="PARAMETERS" value="" />
+    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/bramble-j2se" />
+    <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/All_tests_in_briar_android.xml

@@ -0,0 +1,23 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests in briar-android" type="AndroidJUnit" factoryName="Android JUnit">
+    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
+    <module name="briar-android" />
+    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
+    <option name="ALTERNATIVE_JRE_PATH" />
+    <option name="PACKAGE_NAME" value="" />
+    <option name="MAIN_CLASS_NAME" value="" />
+    <option name="METHOD_NAME" value="" />
+    <option name="TEST_OBJECT" value="package" />
+    <option name="VM_PARAMETERS" value="-ea" />
+    <option name="PARAMETERS" value="" />
+    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/briar-android" />
+    <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/All_tests_in_briar_core.xml

@@ -0,0 +1,23 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests in briar-core" type="AndroidJUnit" factoryName="Android JUnit">
+    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
+    <module name="briar-core" />
+    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
+    <option name="ALTERNATIVE_JRE_PATH" />
+    <option name="PACKAGE_NAME" value="" />
+    <option name="MAIN_CLASS_NAME" value="" />
+    <option name="METHOD_NAME" value="" />
+    <option name="TEST_OBJECT" value="package" />
+    <option name="VM_PARAMETERS" value="-ea" />
+    <option name="PARAMETERS" value="" />
+    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/briar-core" />
+    <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/.gitignore

@@ -1,5 +1,5 @@
 bin
 gen
 build
-local.properties
 .settings
+src/main/res/raw/*.zip

bramble-android/build.gradle

@@ -0,0 +1,95 @@
+import de.undercouch.gradle.tasks.download.Download
+import de.undercouch.gradle.tasks.download.Verify
+
+apply plugin: 'com.android.library'
+apply plugin: 'witness'
+apply plugin: 'de.undercouch.download'
+
+android {
+	compileSdkVersion 27
+	buildToolsVersion '26.0.2'
+
+	defaultConfig {
+		minSdkVersion 14
+		targetSdkVersion 26
+		versionCode 1620
+		versionName "0.16.20"
+		consumerProguardFiles 'proguard-rules.txt'
+	}
+
+	compileOptions {
+		sourceCompatibility JavaVersion.VERSION_1_8
+		targetCompatibility JavaVersion.VERSION_1_8
+	}
+}
+
+dependencies {
+	implementation project(path: ':bramble-core', configuration: 'default')
+	implementation fileTree(dir: 'libs', include: '*.jar')
+
+	annotationProcessor 'com.google.dagger:dagger-compiler:2.0.2'
+
+	compileOnly 'javax.annotation:jsr250-api:1.0'
+}
+
+dependencyVerification {
+	verify = [
+			'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
+			'com.google.dagger:dagger-compiler:2.0.2:dagger-compiler-2.0.2.jar:b74bc9de063dd4c6400b232231f2ef5056145b8fbecbf5382012007dd1c071b3',
+			'com.google.dagger:dagger-producers:2.0-beta:dagger-producers-2.0-beta.jar:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
+			'com.google.dagger:dagger:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
+			'com.google.guava:guava:18.0:guava-18.0.jar:d664fbfc03d2e5ce9cab2a44fb01f1d0bf9dfebeccc1a473b1f9ea31f79f6f99',
+			'com.h2database:h2:1.4.192:h2-1.4.192.jar:225b22e9857235c46c93861410b60b8c81c10dc8985f4faf188985ba5445126c',
+			'com.madgag.spongycastle:core:1.58.0.0:core-1.58.0.0.jar:199617dd5698c5a9312b898c0a4cec7ce9dd8649d07f65d91629f58229d72728',
+			'javax.annotation:jsr250-api:1.0:jsr250-api-1.0.jar:a1a922d0d9b6d183ed3800dfac01d1e1eb159f0e8c6f94736931c1def54a941f',
+			'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
+			'org.bitlet:weupnp:0.1.4:weupnp-0.1.4.jar:88df7e6504929d00bdb832863761385c68ab92af945b04f0770b126270a444fb',
+			'org.jacoco:org.jacoco.agent:0.7.4.201502262128:org.jacoco.agent-0.7.4.201502262128-runtime.jar:e357a0f1d573c2f702a273992b1b6cb661734f66311854efb3778a888515c5b5',
+			'org.jacoco:org.jacoco.agent:0.7.4.201502262128:org.jacoco.agent-0.7.4.201502262128.jar:47b4bec6df11a1118da3953da8b9fa1e7079d6fec857faa1a3cf912e53a6fd4e',
+			'org.jacoco:org.jacoco.ant:0.7.4.201502262128:org.jacoco.ant-0.7.4.201502262128.jar:013ce2a68ba57a3c59215ae0dec4df3498c078062a38c3b94c841fc14450f283',
+			'org.jacoco:org.jacoco.core:0.7.4.201502262128:org.jacoco.core-0.7.4.201502262128.jar:ec4c74554312fac5116350164786f91b35c9e082fa4ea598bfa42b5db05d7abb',
+			'org.jacoco:org.jacoco.report:0.7.4.201502262128:org.jacoco.report-0.7.4.201502262128.jar:7a3554c605e088e7e323b1084656243f0444fa353e2f2dee1f1a4204eb64ff09',
+			'org.ow2.asm:asm-debug-all:5.0.1:asm-debug-all-5.0.1.jar:4734de5b515a454b0096db6971fb068e5f70e6f10bbee2b3bd2fdfe5d978ed57',
+	]
+}
+
+ext.torBinaryDir = 'src/main/res/raw'
+ext.torVersion = '0.2.9.14'
+ext.geoipVersion = '2017-11-06'
+ext.torDownloadUrl = 'https://briarproject.org/build/'
+
+def torBinaries = [
+		"tor_arm"    : '1710ea6c47b7f4c1a88bdf4858c7893837635db10e8866854eed8d61629f50e8',
+		"tor_arm_pie": '974e6949507db8fa2ea45231817c2c3677ed4ccf5488a2252317d744b0be1917',
+		"tor_x86"    : '3a5e45b3f051fcda9353b098b7086e762ffe7ba9242f7d7c8bf6523faaa8b1e9',
+		"tor_x86_pie": 'd1d96d8ce1a4b68accf04850185780d10cd5563d3552f7e1f040f8ca32cb4e51',
+		"geoip"      : '8239b98374493529a29096e45fc5877d4d6fdad0146ad8380b291f90d61484ea'
+]
+
+def downloadBinary(name) {
+	return tasks.create("downloadBinary${name}", Download) {
+		src "${torDownloadUrl}${name}.zip"
+				.replace('tor_', "tor-${torVersion}-")
+				.replace('geoip', "geoip-${geoipVersion}")
+				.replaceAll('_', '-')
+		dest "${torBinaryDir}/${name}.zip"
+		onlyIfNewer true
+	}
+}
+
+def verifyBinary(name, chksum) {
+	return tasks.create([
+			name     : "verifyBinary${name}",
+			type     : Verify,
+			dependsOn: downloadBinary(name)]) {
+		src "${torBinaryDir}/${name}.zip"
+		algorithm 'SHA-256'
+		checksum chksum
+	}
+}
+
+project.afterEvaluate {
+	torBinaries.every { key, value ->
+		preBuild.dependsOn.add(verifyBinary(key, value))
+	}
+}

bramble-android/proguard-rules.txt

@@ -0,0 +1,15 @@
+-keep,includedescriptorclasses class org.briarproject.** { *; }
+
+-keep class org.h2.** { *; }
+-dontwarn org.h2.**
+-dontnote org.h2.**
+
+-keep class dagger.** { *; }
+-dontwarn dagger.**
+-dontnote dagger.**
+
+-dontwarn sun.misc.Unsafe
+-dontnote com.google.common.**
+
+# UPnP library isn't used
+-dontwarn org.bitlet.weupnp.**

bramble-android/src/main/AndroidManifest.xml

@@ -0,0 +1,22 @@
+<manifest
+	package="org.briarproject.bramble"
+	xmlns:android="http://schemas.android.com/apk/res/android">
+
+	<uses-feature android:name="android.hardware.bluetooth"/>
+
+	<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
+	<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
+	<uses-permission android:name="android.permission.BLUETOOTH"/>
+	<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
+	<uses-permission android:name="android.permission.INTERNET"/>
+	<uses-permission android:name="android.permission.READ_LOGS"/>
+	<uses-permission android:name="android.permission.WAKE_LOCK"/>
+
+	<application
+		android:allowBackup="false"
+		android:label="@string/app_name"
+		android:supportsRtl="true">
+
+	</application>
+
+</manifest>

bramble-android/src/main/java/org/briarproject/bramble/BrambleAndroidModule.java

@@ -0,0 +1,13 @@
+package org.briarproject.bramble;
+
+import org.briarproject.bramble.plugin.AndroidPluginModule;
+import org.briarproject.bramble.system.AndroidSystemModule;
+
+import dagger.Module;
+
+@Module(includes = {
+		AndroidPluginModule.class,
+		AndroidSystemModule.class
+})
+public class BrambleAndroidModule {
+}

bramble-android/src/main/java/org/briarproject/bramble/api/system/AndroidExecutor.java

@@ -1,4 +1,4 @@
-package org.briarproject.android.api;
+package org.briarproject.bramble.api.system;
 
 import java.util.concurrent.Callable;
 import java.util.concurrent.Future;

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

@@ -0,0 +1,69 @@
+package org.briarproject.bramble.plugin;
+
+import android.app.Application;
+import android.content.Context;
+
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.BackoffFactory;
+import org.briarproject.bramble.api.plugin.PluginConfig;
+import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
+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.bluetooth.AndroidBluetoothPluginFactory;
+import org.briarproject.bramble.plugin.tcp.AndroidLanTcpPluginFactory;
+import org.briarproject.bramble.plugin.tor.TorPluginFactory;
+
+import java.security.SecureRandom;
+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;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+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 =
+				new AndroidBluetoothPluginFactory(ioExecutor, androidExecutor,
+						appContext, random, eventBus, backoffFactory);
+		DuplexPluginFactory tor = new TorPluginFactory(ioExecutor, scheduler,
+				appContext, locationUtils, reporter, eventBus,
+				torSocketFactory, backoffFactory);
+		DuplexPluginFactory lan = new AndroidLanTcpPluginFactory(ioExecutor,
+				scheduler, backoffFactory, appContext);
+		Collection<DuplexPluginFactory> duplex =
+				Arrays.asList(bluetooth, tor, lan);
+		@NotNullByDefault
+		PluginConfig pluginConfig = new PluginConfig() {
+
+			@Override
+			public Collection<DuplexPluginFactory> getDuplexFactories() {
+				return duplex;
+			}
+
+			@Override
+			public Collection<SimplexPluginFactory> getSimplexFactories() {
+				return Collections.emptyList();
+			}
+		};
+		return pluginConfig;
+	}
+}

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

@@ -0,0 +1,206 @@
+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/bluetooth/AndroidBluetoothPluginFactory.java

@@ -0,0 +1,70 @@
+package org.briarproject.bramble.plugin.bluetooth;
+
+import android.content.Context;
+
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.Backoff;
+import org.briarproject.bramble.api.plugin.BackoffFactory;
+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.DuplexPluginFactory;
+import org.briarproject.bramble.api.system.AndroidExecutor;
+
+import java.security.SecureRandom;
+import java.util.concurrent.Executor;
+
+import javax.annotation.concurrent.Immutable;
+
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
+
+@Immutable
+@NotNullByDefault
+public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
+
+	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
+	private static final int MIN_POLLING_INTERVAL = 60 * 1000; // 1 minute
+	private static final int MAX_POLLING_INTERVAL = 10 * 60 * 1000; // 10 mins
+	private static final double BACKOFF_BASE = 1.2;
+
+	private final Executor ioExecutor;
+	private final AndroidExecutor androidExecutor;
+	private final Context appContext;
+	private final SecureRandom secureRandom;
+	private final EventBus eventBus;
+	private final BackoffFactory backoffFactory;
+
+	public AndroidBluetoothPluginFactory(Executor ioExecutor,
+			AndroidExecutor androidExecutor, Context appContext,
+			SecureRandom secureRandom, EventBus eventBus,
+			BackoffFactory backoffFactory) {
+		this.ioExecutor = ioExecutor;
+		this.androidExecutor = androidExecutor;
+		this.appContext = appContext;
+		this.secureRandom = secureRandom;
+		this.eventBus = eventBus;
+		this.backoffFactory = backoffFactory;
+	}
+
+	@Override
+	public TransportId getId() {
+		return ID;
+	}
+
+	@Override
+	public int getMaxLatency() {
+		return MAX_LATENCY;
+	}
+
+	@Override
+	public DuplexPlugin createPlugin(DuplexPluginCallback callback) {
+		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
+				MAX_POLLING_INTERVAL, BACKOFF_BASE);
+		AndroidBluetoothPlugin plugin = new AndroidBluetoothPlugin(ioExecutor,
+				androidExecutor, appContext, secureRandom, backoff, callback,
+				MAX_LATENCY);
+		eventBus.addListener(plugin);
+		return plugin;
+	}
+}

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

@@ -1,19 +1,22 @@
-package org.briarproject.plugins.droidtooth;
+package org.briarproject.bramble.plugin.bluetooth;
 
 import android.bluetooth.BluetoothSocket;
 
-import org.briarproject.api.plugins.Plugin;
-import org.briarproject.api.plugins.duplex.AbstractDuplexTransportConnection;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.Plugin;
+import org.briarproject.bramble.api.plugin.duplex.AbstractDuplexTransportConnection;
 
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 
-class DroidtoothTransportConnection extends AbstractDuplexTransportConnection {
+@NotNullByDefault
+class AndroidBluetoothTransportConnection
+		extends AbstractDuplexTransportConnection {
 
 	private final BluetoothSocket socket;
 
-	DroidtoothTransportConnection(Plugin plugin, BluetoothSocket socket) {
+	AndroidBluetoothTransportConnection(Plugin plugin, BluetoothSocket socket) {
 		super(plugin);
 		this.socket = socket;
 	}

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

@@ -0,0 +1,196 @@
+package org.briarproject.bramble.plugin.tcp;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.net.ConnectivityManager;
+import android.net.Network;
+import android.net.NetworkInfo;
+import android.net.wifi.WifiInfo;
+import android.net.wifi.WifiManager;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.Backoff;
+import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.Socket;
+import java.net.UnknownHostException;
+import java.util.Collection;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.net.SocketFactory;
+
+import static android.content.Context.CONNECTIVITY_SERVICE;
+import static android.content.Context.WIFI_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 android.os.Build.VERSION.SDK_INT;
+import static java.util.Collections.emptyList;
+import static java.util.Collections.singletonList;
+import static java.util.concurrent.TimeUnit.SECONDS;
+
+@NotNullByDefault
+class AndroidLanTcpPlugin extends LanTcpPlugin {
+
+	// See android.net.wifi.WifiManager
+	private static final String WIFI_AP_STATE_CHANGED_ACTION =
+			"android.net.wifi.WIFI_AP_STATE_CHANGED";
+	private static final int WIFI_AP_STATE_ENABLED = 13;
+
+	private static final byte[] WIFI_AP_ADDRESS_BYTES =
+			{(byte) 192, (byte) 168, 43, 1};
+	private static final InetAddress WIFI_AP_ADDRESS;
+
+	private static final Logger LOG =
+			Logger.getLogger(AndroidLanTcpPlugin.class.getName());
+
+	static {
+		try {
+			WIFI_AP_ADDRESS = InetAddress.getByAddress(WIFI_AP_ADDRESS_BYTES);
+		} catch (UnknownHostException e) {
+			// Should only be thrown if the address has an illegal length
+			throw new AssertionError(e);
+		}
+	}
+
+	private final ScheduledExecutorService scheduler;
+	private final Context appContext;
+	private final ConnectivityManager connectivityManager;
+	@Nullable
+	private final WifiManager wifiManager;
+
+	@Nullable
+	private volatile BroadcastReceiver networkStateReceiver = null;
+	private volatile SocketFactory socketFactory;
+
+	AndroidLanTcpPlugin(Executor ioExecutor, ScheduledExecutorService scheduler,
+			Backoff backoff, Context appContext, DuplexPluginCallback callback,
+			int maxLatency, int maxIdleTime) {
+		super(ioExecutor, backoff, callback, maxLatency, maxIdleTime);
+		this.scheduler = scheduler;
+		this.appContext = appContext;
+		ConnectivityManager connectivityManager = (ConnectivityManager)
+				appContext.getSystemService(CONNECTIVITY_SERVICE);
+		if (connectivityManager == null) throw new AssertionError();
+		this.connectivityManager = connectivityManager;
+		wifiManager = (WifiManager) appContext.getApplicationContext()
+				.getSystemService(WIFI_SERVICE);
+		socketFactory = SocketFactory.getDefault();
+	}
+
+	@Override
+	public void start() {
+		if (used.getAndSet(true)) throw new IllegalStateException();
+		running = true;
+		// Register to receive network status events
+		networkStateReceiver = new NetworkStateReceiver();
+		IntentFilter filter = new IntentFilter();
+		filter.addAction(CONNECTIVITY_ACTION);
+		filter.addAction(WIFI_AP_STATE_CHANGED_ACTION);
+		appContext.registerReceiver(networkStateReceiver, filter);
+	}
+
+	@Override
+	public void stop() {
+		running = false;
+		if (networkStateReceiver != null)
+			appContext.unregisterReceiver(networkStateReceiver);
+		tryToClose(socket);
+	}
+
+	@Override
+	protected Socket createSocket() throws IOException {
+		return socketFactory.createSocket();
+	}
+
+	@Override
+	protected Collection<InetAddress> getLocalIpAddresses() {
+		// If the device doesn't have wifi, don't open any sockets
+		if (wifiManager == null) return emptyList();
+		// If we're connected to a wifi network, use that network
+		WifiInfo info = wifiManager.getConnectionInfo();
+		if (info != null && info.getIpAddress() != 0)
+			return singletonList(intToInetAddress(info.getIpAddress()));
+		// If we're running an access point, return its address
+		if (super.getLocalIpAddresses().contains(WIFI_AP_ADDRESS))
+				return singletonList(WIFI_AP_ADDRESS);
+		// No suitable addresses
+		return emptyList();
+	}
+
+	private InetAddress intToInetAddress(int ip) {
+		byte[] ipBytes = new byte[4];
+		ipBytes[0] = (byte) (ip & 0xFF);
+		ipBytes[1] = (byte) ((ip >> 8) & 0xFF);
+		ipBytes[2] = (byte) ((ip >> 16) & 0xFF);
+		ipBytes[3] = (byte) ((ip >> 24) & 0xFF);
+		try {
+			return InetAddress.getByAddress(ipBytes);
+		} catch (UnknownHostException e) {
+			// Should only be thrown if address has illegal length
+			throw new AssertionError(e);
+		}
+	}
+
+	// On API 21 and later, a socket that is not created with the wifi
+	// network's socket factory may try to connect via another network
+	private SocketFactory getSocketFactory() {
+		if (SDK_INT < 21) return SocketFactory.getDefault();
+		for (Network net : connectivityManager.getAllNetworks()) {
+			NetworkInfo info = connectivityManager.getNetworkInfo(net);
+			if (info != null && info.getType() == TYPE_WIFI)
+				return net.getSocketFactory();
+		}
+		LOG.warning("Could not find suitable socket factory");
+		return SocketFactory.getDefault();
+	}
+
+	private class NetworkStateReceiver extends BroadcastReceiver {
+
+		@Override
+		public void onReceive(Context ctx, Intent i) {
+			if (!running) return;
+			if (isApEnabledEvent(i)) {
+				// The state change may be broadcast before the AP address is
+				// visible, so delay handling the event
+				scheduler.schedule(this::handleConnectivityChange, 1, SECONDS);
+			} else {
+				handleConnectivityChange();
+			}
+		}
+
+		private void handleConnectivityChange() {
+			if (!running) return;
+			Collection<InetAddress> addrs = getLocalIpAddresses();
+			if (addrs.contains(WIFI_AP_ADDRESS)) {
+				LOG.info("Providing wifi hotspot");
+				// There's no corresponding Network object and thus no way
+				// to get a suitable socket factory, so we won't be able to
+				// make outgoing connections on API 21+ if another network
+				// has internet access
+				socketFactory = SocketFactory.getDefault();
+				if (socket == null || socket.isClosed()) bind();
+			} else if (addrs.isEmpty()) {
+				LOG.info("Not connected to wifi");
+				socketFactory = SocketFactory.getDefault();
+				tryToClose(socket);
+			} else {
+				LOG.info("Connected to wifi");
+				socketFactory = getSocketFactory();
+				if (socket == null || socket.isClosed()) bind();
+			}
+		}
+
+		private boolean isApEnabledEvent(Intent i) {
+			return WIFI_AP_STATE_CHANGED_ACTION.equals(i.getAction()) &&
+					i.getIntExtra(EXTRA_WIFI_STATE, 0) == WIFI_AP_STATE_ENABLED;
+		}
+	}
+}

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

@@ -1,18 +1,24 @@
-package org.briarproject.plugins.tcp;
+package org.briarproject.bramble.plugin.tcp;
 
 import android.content.Context;
 
-import org.briarproject.api.TransportId;
-import org.briarproject.api.plugins.Backoff;
-import org.briarproject.api.plugins.BackoffFactory;
-import org.briarproject.api.plugins.duplex.DuplexPlugin;
-import org.briarproject.api.plugins.duplex.DuplexPluginCallback;
-import org.briarproject.api.plugins.duplex.DuplexPluginFactory;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.Backoff;
+import org.briarproject.bramble.api.plugin.BackoffFactory;
+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.DuplexPluginFactory;
 
 import java.util.concurrent.Executor;
+import java.util.concurrent.ScheduledExecutorService;
 
-import static org.briarproject.api.plugins.LanTcpConstants.ID;
+import javax.annotation.concurrent.Immutable;
 
+import static org.briarproject.bramble.api.plugin.LanTcpConstants.ID;
+
+@Immutable
+@NotNullByDefault
 public class AndroidLanTcpPluginFactory implements DuplexPluginFactory {
 
 	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
@@ -22,12 +28,15 @@ public class AndroidLanTcpPluginFactory implements DuplexPluginFactory {
 	private static final double BACKOFF_BASE = 1.2;
 
 	private final Executor ioExecutor;
+	private final ScheduledExecutorService scheduler;
 	private final BackoffFactory backoffFactory;
 	private final Context appContext;
 
 	public AndroidLanTcpPluginFactory(Executor ioExecutor,
-			BackoffFactory backoffFactory, Context appContext) {
+			ScheduledExecutorService scheduler, BackoffFactory backoffFactory,
+			Context appContext) {
 		this.ioExecutor = ioExecutor;
+		this.scheduler = scheduler;
 		this.backoffFactory = backoffFactory;
 		this.appContext = appContext;
 	}
@@ -46,7 +55,7 @@ public class AndroidLanTcpPluginFactory implements DuplexPluginFactory {
 	public DuplexPlugin createPlugin(DuplexPluginCallback callback) {
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		return new AndroidLanTcpPlugin(ioExecutor, backoff, appContext,
-				callback, MAX_LATENCY, MAX_IDLE_TIME);
+		return new AndroidLanTcpPlugin(ioExecutor, scheduler, backoff,
+				appContext, callback, MAX_LATENCY, MAX_IDLE_TIME);
 	}
 }

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

@@ -1,18 +1,18 @@
-package org.briarproject.plugins.tor;
+package org.briarproject.bramble.plugin.tor;
 
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Set;
 
-public class TorNetworkMetadata {
+class TorNetworkMetadata {
 
 	// See https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2
 	// and https://trac.torproject.org/projects/tor/wiki/doc/OONI/censorshipwiki
 	// TODO: get a more complete list
 	private static final Set<String> BLOCKED_IN_COUNTRIES =
-			new HashSet<String>(Arrays.asList("CN", "IR", "SY", "ZZ"));
+			new HashSet<>(Arrays.asList("CN", "IR", "SY", "ZZ"));
 
-	public static boolean isTorProbablyBlocked(String countryCode) {
+	static boolean isTorProbablyBlocked(String countryCode) {
 		return BLOCKED_IN_COUNTRIES.contains(countryCode);
 	}
 }

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

@@ -1,4 +1,4 @@
-package org.briarproject.plugins.tor;
+package org.briarproject.bramble.plugin.tor;
 
 import android.content.BroadcastReceiver;
 import android.content.Context;
@@ -7,6 +7,7 @@ import android.content.IntentFilter;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageManager.NameNotFoundException;
+import android.content.res.Resources;
 import android.net.ConnectivityManager;
 import android.net.NetworkInfo;
 import android.os.FileObserver;
@@ -15,27 +16,29 @@ import android.os.PowerManager;
 import net.freehaven.tor.control.EventHandler;
 import net.freehaven.tor.control.TorControlConnection;
 
-import org.briarproject.android.util.AndroidUtils;
-import org.briarproject.api.TransportId;
-import org.briarproject.api.contact.ContactId;
-import org.briarproject.api.crypto.PseudoRandom;
-import org.briarproject.api.data.BdfList;
-import org.briarproject.api.event.Event;
-import org.briarproject.api.event.EventListener;
-import org.briarproject.api.event.SettingsUpdatedEvent;
-import org.briarproject.api.keyagreement.KeyAgreementListener;
-import org.briarproject.api.nullsafety.NotNullByDefault;
-import org.briarproject.api.plugins.Backoff;
-import org.briarproject.api.plugins.TorConstants;
-import org.briarproject.api.plugins.duplex.DuplexPlugin;
-import org.briarproject.api.plugins.duplex.DuplexPluginCallback;
-import org.briarproject.api.plugins.duplex.DuplexTransportConnection;
-import org.briarproject.api.properties.TransportProperties;
-import org.briarproject.api.reporting.DevReporter;
-import org.briarproject.api.settings.Settings;
-import org.briarproject.api.system.LocationUtils;
-import org.briarproject.util.IoUtils;
-import org.briarproject.util.StringUtils;
+import org.briarproject.bramble.PoliteExecutor;
+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.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.TorConstants;
+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.properties.TransportProperties;
+import org.briarproject.bramble.api.reporting.DevReporter;
+import org.briarproject.bramble.api.settings.Settings;
+import org.briarproject.bramble.api.settings.event.SettingsUpdatedEvent;
+import org.briarproject.bramble.api.system.LocationUtils;
+import org.briarproject.bramble.util.AndroidUtils;
+import org.briarproject.bramble.util.IoUtils;
+import org.briarproject.bramble.util.StringUtils;
 
 import java.io.Closeable;
 import java.io.EOFException;
@@ -53,10 +56,14 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+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.logging.Logger;
 import java.util.regex.Pattern;
 import java.util.zip.ZipInputStream;
@@ -67,21 +74,33 @@ 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;
 import static net.freehaven.tor.control.TorControlCommands.HS_PRIVKEY;
-import static org.briarproject.api.plugins.TorConstants.CONTROL_PORT;
-import static org.briarproject.util.PrivacyUtils.scrubOnion;
+import static org.briarproject.bramble.api.plugin.TorConstants.CONTROL_PORT;
+import static org.briarproject.bramble.api.plugin.TorConstants.ID;
+import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK;
+import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_ALWAYS;
+import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_NEVER;
+import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_WIFI;
+import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_PORT;
+import static org.briarproject.bramble.api.plugin.TorConstants.PROP_ONION;
+import static org.briarproject.bramble.util.PrivacyUtils.scrubOnion;
 
-@NotNullByDefault
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
 class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
-	private static final String PROP_ONION = "onion";
 	private static final String[] EVENTS = {
 			"CIRC", "ORCONN", "HS_DESC", "NOTICE", "WARN", "ERR"
 	};
@@ -91,7 +110,8 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private static final Logger LOG =
 			Logger.getLogger(TorPlugin.class.getName());
 
-	private final Executor ioExecutor;
+	private final Executor ioExecutor, connectionStatusExecutor;
+	private final ScheduledExecutorService scheduler;
 	private final Context appContext;
 	private final LocationUtils locationUtils;
 	private final DevReporter reporter;
@@ -104,24 +124,23 @@ 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 AtomicReference<Future<?>> connectivityCheck =
+			new AtomicReference<>();
 	private final AtomicBoolean used = new AtomicBoolean(false);
 
 	private volatile boolean running = false;
-	@Nullable
 	private volatile ServerSocket socket = null;
-	@Nullable
 	private volatile Socket controlSocket = null;
-	@Nullable
 	private volatile TorControlConnection controlConnection = null;
-	@Nullable
 	private volatile BroadcastReceiver networkStateReceiver = null;
 
-	TorPlugin(Executor ioExecutor, Context appContext,
-			LocationUtils locationUtils, DevReporter reporter,
-			SocketFactory torSocketFactory, Backoff backoff,
-			DuplexPluginCallback callback, String architecture, int maxLatency,
-			int maxIdleTime) {
+	TorPlugin(Executor ioExecutor, ScheduledExecutorService scheduler,
+			Context appContext, LocationUtils locationUtils,
+			DevReporter reporter, SocketFactory torSocketFactory,
+			Backoff backoff, DuplexPluginCallback callback,
+			String architecture, int maxLatency, int maxIdleTime) {
 		this.ioExecutor = ioExecutor;
+		this.scheduler = scheduler;
 		this.appContext = appContext;
 		this.locationUtils = locationUtils;
 		this.reporter = reporter;
@@ -143,8 +162,12 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		cookieFile = new File(torDirectory, ".tor/control_auth_cookie");
 		Object o = appContext.getSystemService(POWER_SERVICE);
 		PowerManager pm = (PowerManager) o;
-		wakeLock = pm.newWakeLock(PARTIAL_WAKE_LOCK, "TorPlugin");
+		// This tag will prevent Huawei's powermanager from killing us.
+		wakeLock = pm.newWakeLock(PARTIAL_WAKE_LOCK, "LocationManagerService");
 		wakeLock.setReferenceCounted(false);
+		// Don't execute more than one connection status check at a time
+		connectionStatusExecutor = new PoliteExecutor("TorPlugin",
+				ioExecutor, 1);
 	}
 
 	@Override
@@ -163,14 +186,18 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	@Override
-	public boolean start() throws IOException {
+	public void start() throws PluginException {
 		if (used.getAndSet(true)) throw new IllegalStateException();
 		// Install or update the assets if necessary
 		if (!assetsAreUpToDate()) installAssets();
 		LOG.info("Starting Tor");
 		// Watch for the auth cookie file being updated
-		cookieFile.getParentFile().mkdirs();
-		cookieFile.createNewFile();
+		try {
+			cookieFile.getParentFile().mkdirs();
+			cookieFile.createNewFile();
+		} catch (IOException e) {
+			throw new PluginException(e);
+		}
 		CountDownLatch latch = new CountDownLatch(1);
 		FileObserver obs = new WriteObserver(cookieFile, latch);
 		obs.startWatching();
@@ -178,19 +205,31 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		String torPath = torFile.getAbsolutePath();
 		String configPath = configFile.getAbsolutePath();
 		String pid = String.valueOf(android.os.Process.myPid());
-		String[] cmd = {torPath, "-f", configPath, OWNER, pid};
-		String[] env = {"HOME=" + torDirectory.getAbsolutePath()};
 		Process torProcess;
+		ProcessBuilder pb =
+				new ProcessBuilder(torPath, "-f", configPath, OWNER, pid);
+		Map<String, String> env = pb.environment();
+		env.put("HOME", torDirectory.getAbsolutePath());
+		pb.directory(torDirectory);
 		try {
-			torProcess = Runtime.getRuntime().exec(cmd, env, torDirectory);
-		} catch (SecurityException e) {
-			throw new IOException(e);
+			torProcess = pb.start();
+		} catch (SecurityException | IOException e) {
+			throw new PluginException(e);
 		}
 		// Log the process's standard output until it detaches
 		if (LOG.isLoggable(INFO)) {
 			Scanner stdout = new Scanner(torProcess.getInputStream());
-			while (stdout.hasNextLine()) LOG.info(stdout.nextLine());
+			Scanner stderr = new Scanner(torProcess.getErrorStream());
+			while (stdout.hasNextLine() || stderr.hasNextLine()) {
+				if (stdout.hasNextLine()) {
+					LOG.info(stdout.nextLine());
+				}
+				if (stderr.hasNextLine()) {
+					LOG.info(stderr.nextLine());
+				}
+			}
 			stdout.close();
+			stderr.close();
 		}
 		try {
 			// Wait for the process to detach or exit
@@ -198,43 +237,50 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			if (exit != 0) {
 				if (LOG.isLoggable(WARNING))
 					LOG.warning("Tor exited with value " + exit);
-				return false;
+				throw new PluginException();
 			}
 			// Wait for the auth cookie file to be created/updated
 			if (!latch.await(COOKIE_TIMEOUT, MILLISECONDS)) {
 				LOG.warning("Auth cookie not created");
 				if (LOG.isLoggable(INFO)) listFiles(torDirectory);
-				return false;
+				throw new PluginException();
 			}
 		} catch (InterruptedException e) {
 			LOG.warning("Interrupted while starting Tor");
 			Thread.currentThread().interrupt();
-			return false;
+			throw new PluginException();
 		}
-		// Open a control connection and authenticate using the cookie file
-		controlSocket = new Socket("127.0.0.1", CONTROL_PORT);
-		controlConnection = new TorControlConnection(controlSocket);
-		controlConnection.authenticate(read(cookieFile));
-		// Tell Tor to exit when the control connection is closed
-		controlConnection.takeOwnership();
-		controlConnection.resetConf(Collections.singletonList(OWNER));
-		running = true;
-		// Register to receive events from the Tor process
-		controlConnection.setEventHandler(this);
-		controlConnection.setEvents(Arrays.asList(EVENTS));
-		// Check whether Tor has already bootstrapped
-		String phase = controlConnection.getInfo("status/bootstrap-phase");
-		if (phase != null && phase.contains("PROGRESS=100")) {
-			LOG.info("Tor has already bootstrapped");
-			connectionStatus.setBootstrapped();
+		try {
+			// Open a control connection and authenticate using the cookie file
+			controlSocket = new Socket("127.0.0.1", CONTROL_PORT);
+			controlConnection = new TorControlConnection(controlSocket);
+			controlConnection.authenticate(read(cookieFile));
+			// Tell Tor to exit when the control connection is closed
+			controlConnection.takeOwnership();
+			controlConnection.resetConf(Collections.singletonList(OWNER));
+			running = true;
+			// Register to receive events from the Tor process
+			controlConnection.setEventHandler(this);
+			controlConnection.setEvents(Arrays.asList(EVENTS));
+			// Check whether Tor has already bootstrapped
+			String phase = controlConnection.getInfo("status/bootstrap-phase");
+			if (phase != null && phase.contains("PROGRESS=100")) {
+				LOG.info("Tor has already bootstrapped");
+				connectionStatus.setBootstrapped();
+			}
+		} catch (IOException e) {
+			throw new PluginException(e);
 		}
 		// Register to receive network status events
 		networkStateReceiver = new NetworkStateReceiver();
-		IntentFilter filter = new IntentFilter(CONNECTIVITY_ACTION);
+		IntentFilter filter = new IntentFilter();
+		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();
-		return true;
 	}
 
 	private boolean assetsAreUpToDate() {
@@ -247,7 +293,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		}
 	}
 
-	private void installAssets() throws IOException {
+	private void installAssets() throws PluginException {
 		InputStream in = null;
 		OutputStream out = null;
 		try {
@@ -270,30 +316,36 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		} catch (IOException e) {
 			tryToClose(in);
 			tryToClose(out);
-			throw e;
+			throw new PluginException(e);
 		}
 	}
 
 	private InputStream getTorInputStream() throws IOException {
 		if (LOG.isLoggable(INFO))
 			LOG.info("Installing Tor binary for " + architecture);
-		String filename = "tor-" + architecture + ".zip";
-		InputStream in = appContext.getResources().getAssets().open(filename);
+		int resId = getResourceId("tor_" + architecture);
+		InputStream in = appContext.getResources().openRawResource(resId);
 		ZipInputStream zin = new ZipInputStream(in);
 		if (zin.getNextEntry() == null) throw new IOException();
 		return zin;
 	}
 
 	private InputStream getGeoIpInputStream() throws IOException {
-		String filename = "geoip.zip";
-		InputStream in = appContext.getResources().getAssets().open(filename);
+		int resId = getResourceId("geoip");
+		InputStream in = appContext.getResources().openRawResource(resId);
 		ZipInputStream zin = new ZipInputStream(in);
 		if (zin.getNextEntry() == null) throw new IOException();
 		return zin;
 	}
 
 	private InputStream getConfigInputStream() throws IOException {
-		return appContext.getResources().getAssets().open("torrc");
+		int resId = getResourceId("torrc");
+		return appContext.getResources().openRawResource(resId);
+	}
+
+	private int getResourceId(String filename) {
+		Resources res = appContext.getResources();
+		return res.getIdentifier(filename, "raw", appContext.getPackageName());
 	}
 
 	private void tryToClose(@Nullable Closeable c) {
@@ -338,57 +390,45 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void sendDevReports() {
-		ioExecutor.execute(new Runnable() {
-			@Override
-			public void run() {
-				// TODO: Trigger this with a TransportEnabledEvent
-				File reportDir = AndroidUtils.getReportDir(appContext);
-				reporter.sendReports(reportDir);
-			}
+		ioExecutor.execute(() -> {
+			// TODO: Trigger this with a TransportEnabledEvent
+			File reportDir = AndroidUtils.getReportDir(appContext);
+			reporter.sendReports(reportDir);
 		});
 	}
 
 	private void bind() {
-		ioExecutor.execute(new Runnable() {
-			@Override
-			public void run() {
-				// If there's already a port number stored in config, reuse it
-				String portString = callback.getSettings().get("port");
-				int port;
-				if (StringUtils.isNullOrEmpty(portString)) port = 0;
-				else port = Integer.parseInt(portString);
-				// Bind a server socket to receive connections from Tor
-				ServerSocket ss = null;
-				try {
-					ss = new ServerSocket();
-					ss.bind(new InetSocketAddress("127.0.0.1", port));
-				} catch (IOException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
-					tryToClose(ss);
-					return;
-				}
-				if (!running) {
-					tryToClose(ss);
-					return;
-				}
-				socket = ss;
-				// Store the port number
-				final String localPort = String.valueOf(ss.getLocalPort());
-				Settings s = new Settings();
-				s.put("port", localPort);
-				callback.mergeSettings(s);
-				// Create a hidden service if necessary
-				ioExecutor.execute(new Runnable() {
-					@Override
-					public void run() {
-						publishHiddenService(localPort);
-					}
-				});
-				backoff.reset();
-				// Accept incoming hidden service connections from Tor
-				acceptContactConnections(ss);
+		ioExecutor.execute(() -> {
+			// If there's already a port number stored in config, reuse it
+			String portString = callback.getSettings().get(PREF_TOR_PORT);
+			int port;
+			if (StringUtils.isNullOrEmpty(portString)) port = 0;
+			else port = Integer.parseInt(portString);
+			// Bind a server socket to receive connections from Tor
+			ServerSocket ss = null;
+			try {
+				ss = new ServerSocket();
+				ss.bind(new InetSocketAddress("127.0.0.1", port));
+			} catch (IOException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+				tryToClose(ss);
+				return;
 			}
+			if (!running) {
+				tryToClose(ss);
+				return;
+			}
+			socket = ss;
+			// Store the port number
+			String localPort = String.valueOf(ss.getLocalPort());
+			Settings s = new Settings();
+			s.put(PREF_TOR_PORT, localPort);
+			callback.mergeSettings(s);
+			// Create a hidden service if necessary
+			ioExecutor.execute(() -> publishHiddenService(localPort));
+			backoff.reset();
+			// Accept incoming hidden service connections from Tor
+			acceptContactConnections(ss);
 		});
 	}
 
@@ -471,7 +511,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	@Override
-	public void stop() throws IOException {
+	public void stop() throws PluginException {
 		running = false;
 		tryToClose(socket);
 		if (networkStateReceiver != null)
@@ -508,20 +548,21 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	public void poll(Collection<ContactId> connected) {
 		if (!isRunning()) return;
 		backoff.increment();
-		// TODO: Pass properties to connectAndCallBack()
-		for (ContactId c : callback.getRemoteProperties().keySet())
-			if (!connected.contains(c)) connectAndCallBack(c);
+		Map<ContactId, TransportProperties> remote =
+				callback.getRemoteProperties();
+		for (Entry<ContactId, TransportProperties> e : remote.entrySet()) {
+			ContactId c = e.getKey();
+			if (!connected.contains(c)) connectAndCallBack(c, e.getValue());
+		}
 	}
 
-	private void connectAndCallBack(final ContactId c) {
-		ioExecutor.execute(new Runnable() {
-			@Override
-			public void run() {
-				DuplexTransportConnection d = createConnection(c);
-				if (d != null) {
-					backoff.reset();
-					callback.outgoingConnectionCreated(c, d);
-				}
+	private void connectAndCallBack(ContactId c, TransportProperties p) {
+		ioExecutor.execute(() -> {
+			if (!isRunning()) return;
+			DuplexTransportConnection d = createConnection(p);
+			if (d != null) {
+				backoff.reset();
+				callback.outgoingConnectionCreated(c, d);
 			}
 		});
 	}
@@ -529,8 +570,11 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	@Override
 	public DuplexTransportConnection createConnection(ContactId c) {
 		if (!isRunning()) return null;
-		TransportProperties p = callback.getRemoteProperties().get(c);
-		if (p == null) return null;
+		return createConnection(callback.getRemoteProperties(c));
+	}
+
+	@Nullable
+	private DuplexTransportConnection createConnection(TransportProperties p) {
 		String onion = p.get(PROP_ONION);
 		if (StringUtils.isNullOrEmpty(onion)) return null;
 		if (!ONION.matcher(onion).matches()) {
@@ -558,17 +602,6 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		}
 	}
 
-	@Override
-	public boolean supportsInvitations() {
-		return false;
-	}
-
-	@Override
-	public DuplexTransportConnection createInvitationConnection(PseudoRandom r,
-			long timeout, boolean alice) {
-		throw new UnsupportedOperationException();
-	}
-
 	@Override
 	public boolean supportsKeyAgreement() {
 		return false;
@@ -581,7 +614,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
-			byte[] commitment, BdfList descriptor, long timeout) {
+			byte[] commitment, BdfList descriptor) {
 		throw new UnsupportedOperationException();
 	}
 
@@ -605,6 +638,8 @@ 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
@@ -644,7 +679,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		}
 
 		@Override
-		public void onEvent(int event, String path) {
+		public void onEvent(int event, @Nullable String path) {
 			stopWatching();
 			latch.countDown();
 		}
@@ -653,7 +688,8 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	@Override
 	public void eventOccurred(Event e) {
 		if (e instanceof SettingsUpdatedEvent) {
-			if (((SettingsUpdatedEvent) e).getNamespace().equals("tor")) {
+			SettingsUpdatedEvent s = (SettingsUpdatedEvent) e;
+			if (s.getNamespace().equals(ID.getString())) {
 				LOG.info("Tor settings updated");
 				updateConnectionStatus();
 			}
@@ -661,58 +697,65 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void updateConnectionStatus() {
-		ioExecutor.execute(new Runnable() {
-			@Override
-			public void run() {
-				if (!running) return;
+		connectionStatusExecutor.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);
 
-				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();
-				boolean useMobileData = s.getBoolean("torOverMobile", true);
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Online: " + online + ", wifi: " + wifi);
+				if ("".equals(country)) LOG.info("Country code unknown");
+				else LOG.info("Country code: " + country);
+			}
 
-				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 (!wifi && !useMobileData) {
-						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);
+			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;
-			if (CONNECTIVITY_ACTION.equals(i.getAction())) {
-				LOG.info("Detected connectivity change");
-				updateConnectionStatus();
+			String action = i.getAction();
+			if (LOG.isLoggable(INFO)) LOG.info("Received broadcast " + action);
+			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

@@ -1,25 +1,30 @@
-package org.briarproject.plugins.tor;
+package org.briarproject.bramble.plugin.tor;
 
 import android.content.Context;
 import android.os.Build;
 
-import org.briarproject.android.util.AndroidUtils;
-import org.briarproject.api.TransportId;
-import org.briarproject.api.event.EventBus;
-import org.briarproject.api.plugins.Backoff;
-import org.briarproject.api.plugins.BackoffFactory;
-import org.briarproject.api.plugins.TorConstants;
-import org.briarproject.api.plugins.duplex.DuplexPlugin;
-import org.briarproject.api.plugins.duplex.DuplexPluginCallback;
-import org.briarproject.api.plugins.duplex.DuplexPluginFactory;
-import org.briarproject.api.reporting.DevReporter;
-import org.briarproject.api.system.LocationUtils;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.Backoff;
+import org.briarproject.bramble.api.plugin.BackoffFactory;
+import org.briarproject.bramble.api.plugin.TorConstants;
+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.DuplexPluginFactory;
+import org.briarproject.bramble.api.reporting.DevReporter;
+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;
 import javax.net.SocketFactory;
 
+@Immutable
+@NotNullByDefault
 public class TorPluginFactory implements DuplexPluginFactory {
 
 	private static final Logger LOG =
@@ -32,6 +37,7 @@ 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;
@@ -39,11 +45,13 @@ public class TorPluginFactory implements DuplexPluginFactory {
 	private final SocketFactory torSocketFactory;
 	private final BackoffFactory backoffFactory;
 
-	public TorPluginFactory(Executor ioExecutor, Context appContext,
+	public TorPluginFactory(Executor ioExecutor,
+			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;
@@ -81,13 +89,13 @@ public class TorPluginFactory implements DuplexPluginFactory {
 			return null;
 		}
 		// Use position-independent executable for SDK >= 16
-		if (Build.VERSION.SDK_INT >= 16) architecture += "-pie";
+		if (Build.VERSION.SDK_INT >= 16) architecture += "_pie";
 
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		TorPlugin plugin = new TorPlugin(ioExecutor, appContext, locationUtils,
-				reporter, torSocketFactory, backoff, callback, architecture,
-				MAX_LATENCY, MAX_IDLE_TIME);
+		TorPlugin plugin = new TorPlugin(ioExecutor, scheduler, appContext,
+				locationUtils, reporter, torSocketFactory, backoff, callback,
+				architecture, MAX_LATENCY, MAX_IDLE_TIME);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

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

@@ -1,13 +1,16 @@
-package org.briarproject.plugins.tor;
+package org.briarproject.bramble.plugin.tor;
 
-import org.briarproject.api.plugins.Plugin;
-import org.briarproject.api.plugins.duplex.AbstractDuplexTransportConnection;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.Plugin;
+import org.briarproject.bramble.api.plugin.duplex.AbstractDuplexTransportConnection;
+import org.briarproject.bramble.util.IoUtils;
 
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.Socket;
 
+@NotNullByDefault
 class TorTransportConnection extends AbstractDuplexTransportConnection {
 
 	private final Socket socket;
@@ -19,12 +22,12 @@ class TorTransportConnection extends AbstractDuplexTransportConnection {
 
 	@Override
 	protected InputStream getInputStream() throws IOException {
-		return socket.getInputStream();
+		return IoUtils.getInputStream(socket);
 	}
 
 	@Override
 	protected OutputStream getOutputStream() throws IOException {
-		return socket.getOutputStream();
+		return IoUtils.getOutputStream(socket);
 	}
 
 	@Override

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

@@ -1,10 +1,10 @@
-package org.briarproject.system;
+package org.briarproject.bramble.system;
 
 import android.app.Application;
 import android.os.Handler;
 import android.os.Looper;
 
-import org.briarproject.android.api.AndroidExecutor;
+import org.briarproject.bramble.api.system.AndroidExecutor;
 
 import java.util.concurrent.Callable;
 import java.util.concurrent.CountDownLatch;
@@ -27,14 +27,11 @@ class AndroidExecutorImpl implements AndroidExecutor {
 	@Inject
 	AndroidExecutorImpl(Application app) {
 		uiHandler = new Handler(app.getApplicationContext().getMainLooper());
-		loop = new Runnable() {
-			@Override
-			public void run() {
-				Looper.prepare();
-				backgroundHandler = new Handler();
-				startLatch.countDown();
-				Looper.loop();
-			}
+		loop = () -> {
+			Looper.prepare();
+			backgroundHandler = new Handler();
+			startLatch.countDown();
+			Looper.loop();
 		};
 	}
 

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

@@ -1,4 +1,4 @@
-package org.briarproject.system;
+package org.briarproject.bramble.system;
 
 import android.annotation.SuppressLint;
 import android.app.Application;
@@ -6,7 +6,8 @@ import android.content.Context;
 import android.telephony.TelephonyManager;
 import android.text.TextUtils;
 
-import org.briarproject.api.system.LocationUtils;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.LocationUtils;
 
 import java.util.Locale;
 import java.util.logging.Logger;
@@ -15,6 +16,7 @@ import javax.inject.Inject;
 
 import static android.content.Context.TELEPHONY_SERVICE;
 
+@NotNullByDefault
 class AndroidLocationUtils implements LocationUtils {
 
 	private static final Logger LOG =
@@ -23,7 +25,7 @@ class AndroidLocationUtils implements LocationUtils {
 	private final Context appContext;
 
 	@Inject
-	public AndroidLocationUtils(Application app) {
+	AndroidLocationUtils(Application app) {
 		appContext = app.getApplicationContext();
 	}
 
@@ -44,6 +46,7 @@ class AndroidLocationUtils implements LocationUtils {
 	 * some reason - both that class and {@code Context.COUNTRY_CODE} are
 	 * annotated {@code @hide}.
 	 */
+	@Override
 	@SuppressLint("DefaultLocale")
 	public String getCurrentCountry() {
 		String countryCode = getCountryFromPhoneNetwork();

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

@@ -0,0 +1,93 @@
+package org.briarproject.bramble.system;
+
+import android.app.Application;
+import android.bluetooth.BluetoothAdapter;
+import android.bluetooth.BluetoothDevice;
+import android.content.ContentResolver;
+import android.content.Context;
+import android.net.wifi.WifiConfiguration;
+import android.net.wifi.WifiManager;
+import android.os.Build;
+import android.os.Parcel;
+import android.provider.Settings;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.util.List;
+
+import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
+
+import static android.content.Context.WIFI_SERVICE;
+import static android.provider.Settings.Secure.ANDROID_ID;
+
+@Immutable
+@NotNullByDefault
+class AndroidSecureRandomProvider extends LinuxSecureRandomProvider {
+
+	private static final int SEED_LENGTH = 32;
+
+	private final Context appContext;
+
+	@Inject
+	AndroidSecureRandomProvider(Application app) {
+		appContext = app.getApplicationContext();
+	}
+
+	@Override
+	protected void writeToEntropyPool(DataOutputStream out) throws IOException {
+		super.writeToEntropyPool(out);
+		out.writeInt(android.os.Process.myPid());
+		out.writeInt(android.os.Process.myTid());
+		out.writeInt(android.os.Process.myUid());
+		if (Build.FINGERPRINT != null) out.writeUTF(Build.FINGERPRINT);
+		if (Build.SERIAL != null) out.writeUTF(Build.SERIAL);
+		ContentResolver contentResolver = appContext.getContentResolver();
+		String id = Settings.Secure.getString(contentResolver, ANDROID_ID);
+		if (id != null) out.writeUTF(id);
+		Parcel parcel = Parcel.obtain();
+		WifiManager wm =
+				(WifiManager) appContext.getSystemService(WIFI_SERVICE);
+		List<WifiConfiguration> configs = wm.getConfiguredNetworks();
+		if (configs != null) {
+			for (WifiConfiguration config : configs)
+				parcel.writeParcelable(config, 0);
+		}
+		BluetoothAdapter bt = BluetoothAdapter.getDefaultAdapter();
+		if (bt != null) {
+			for (BluetoothDevice device : bt.getBondedDevices())
+				parcel.writeParcelable(device, 0);
+		}
+		out.write(parcel.marshall());
+		parcel.recycle();
+	}
+
+	@Override
+	protected void writeSeed() {
+		super.writeSeed();
+		if (Build.VERSION.SDK_INT >= 16 && Build.VERSION.SDK_INT <= 18)
+			applyOpenSslFix();
+	}
+
+	// Based on https://android-developers.googleblog.com/2013/08/some-securerandom-thoughts.html
+	private void applyOpenSslFix() {
+		byte[] seed = new LinuxSecureRandomSpi().engineGenerateSeed(
+				SEED_LENGTH);
+		try {
+			// Seed the OpenSSL PRNG
+			Class.forName("org.apache.harmony.xnet.provider.jsse.NativeCrypto")
+					.getMethod("RAND_seed", byte[].class)
+					.invoke(null, seed);
+			// Mix the output of the Linux PRNG into the OpenSSL PRNG
+			int bytesRead = (Integer) Class.forName(
+					"org.apache.harmony.xnet.provider.jsse.NativeCrypto")
+					.getMethod("RAND_load_file", String.class, long.class)
+					.invoke(null, "/dev/urandom", 1024);
+			if (bytesRead != 1024) throw new IOException();
+		} catch (Exception e) {
+			throw new SecurityException(e);
+		}
+	}
+}

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

@@ -0,0 +1,33 @@
+package org.briarproject.bramble.system;
+
+import android.app.Application;
+
+import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.bramble.api.system.LocationUtils;
+import org.briarproject.bramble.api.system.SecureRandomProvider;
+
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class AndroidSystemModule {
+
+	@Provides
+	@Singleton
+	SecureRandomProvider provideSecureRandomProvider(Application app) {
+		return new AndroidSecureRandomProvider(app);
+	}
+
+	@Provides
+	LocationUtils provideLocationUtils(Application app) {
+		return new AndroidLocationUtils(app);
+	}
+
+	@Provides
+	@Singleton
+	AndroidExecutor provideAndroidExecutor(Application app) {
+		return new AndroidExecutorImpl(app);
+	}
+}

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

@@ -0,0 +1,70 @@
+package org.briarproject.bramble.util;
+
+import android.bluetooth.BluetoothAdapter;
+import android.content.Context;
+import android.os.Build;
+import android.provider.Settings;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+
+import static android.content.Context.MODE_PRIVATE;
+
+public class AndroidUtils {
+
+	// Fake Bluetooth address returned by BluetoothAdapter on API 23 and later
+	private static final String FAKE_BLUETOOTH_ADDRESS = "02:00:00:00:00:00";
+
+	private static final String STORED_REPORTS = "dev-reports";
+
+	@SuppressWarnings("deprecation")
+	public static Collection<String> getSupportedArchitectures() {
+		List<String> abis = new ArrayList<>();
+		if (Build.VERSION.SDK_INT >= 21) {
+			abis.addAll(Arrays.asList(Build.SUPPORTED_ABIS));
+		} else {
+			abis.add(Build.CPU_ABI);
+			if (Build.CPU_ABI2 != null) abis.add(Build.CPU_ABI2);
+		}
+		return abis;
+	}
+
+	public static String getBluetoothAddress(Context ctx,
+			BluetoothAdapter adapter) {
+		// Return the adapter's address if it's valid and not fake
+		String address = adapter.getAddress();
+		if (isValidBluetoothAddress(address)) return address;
+		// Return the address from settings if it's valid and not fake
+		address = Settings.Secure.getString(ctx.getContentResolver(),
+				"bluetooth_address");
+		if (isValidBluetoothAddress(address)) return address;
+		// Let the caller know we can't find the address
+		return "";
+	}
+
+	private static boolean isValidBluetoothAddress(String address) {
+		return !StringUtils.isNullOrEmpty(address)
+				&& BluetoothAdapter.checkBluetoothAddress(address)
+				&& !address.equals(FAKE_BLUETOOTH_ADDRESS);
+	}
+
+	public static void deleteAppData(Context ctx) {
+		File dataDir = new File(ctx.getApplicationInfo().dataDir);
+		File[] children = dataDir.listFiles();
+		if (children != null) {
+			for (File child : children) {
+				if (!child.getName().equals("lib"))
+					IoUtils.deleteFileOrDir(child);
+			}
+		}
+		// Recreate the cache dir as some OpenGL drivers expect it to exist
+		new File(dataDir, "cache").mkdir();
+	}
+
+	public static File getReportDir(Context ctx) {
+		return ctx.getDir(STORED_REPORTS, MODE_PRIVATE);
+	}
+}

bramble-android/src/main/res/values/strings.xml

@@ -0,0 +1,3 @@
+<resources>
+	<string name="app_name">Bramble</string>
+</resources>

bramble-api/build.gradle

@@ -0,0 +1,55 @@
+apply plugin: 'java-library'
+sourceCompatibility = 1.8
+targetCompatibility = 1.8
+
+apply plugin: 'witness'
+
+dependencies {
+	implementation "com.google.dagger:dagger:2.0.2"
+	implementation 'com.google.code.findbugs:jsr305:3.0.2'
+
+	testImplementation 'junit:junit:4.12'
+	testImplementation "org.jmock:jmock:2.8.2"
+	testImplementation "org.jmock:jmock-junit4:2.8.2"
+	testImplementation "org.jmock:jmock-legacy:2.8.2"
+	testImplementation "org.hamcrest:hamcrest-library:1.3"
+	testImplementation "org.hamcrest:hamcrest-core:1.3"
+}
+
+dependencyVerification {
+	verify = [
+			'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
+			'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
+			'com.google.dagger:dagger:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
+			'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
+			'junit:junit:4.12:junit-4.12.jar:59721f0805e223d84b90677887d9ff567dc534d7c502ca903c0c2b17f05c116a',
+			'org.apache.ant:ant-launcher:1.9.4:ant-launcher-1.9.4.jar:7bccea20b41801ca17bcbc909a78c835d0f443f12d639c77bd6ae3d05861608d',
+			'org.apache.ant:ant:1.9.4:ant-1.9.4.jar:649ae0730251de07b8913f49286d46bba7b92d47c5f332610aa426c4f02161d8',
+			'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
+			'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
+			'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
+			'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',
+			'org.jmock:jmock-legacy:2.8.2:jmock-legacy-2.8.2.jar:f2b985a5c08a9edb7f37612330c058809da3f6a6d63ce792426ebf8ff0d6d31b',
+			'org.jmock:jmock-testjar:2.8.2:jmock-testjar-2.8.2.jar:8900860f72c474e027cf97fe78dcbf154a1aa7fc62b6845c5fb4e4f3c7bc8760',
+			'org.jmock:jmock:2.8.2:jmock-2.8.2.jar:6c73cb4a2e6dbfb61fd99c9a768539c170ab6568e57846bd60dbf19596b65b16',
+			'org.objenesis:objenesis:2.1:objenesis-2.1.jar:c74330cc6b806c804fd37e74487b4fe5d7c2750c5e15fbc6efa13bdee1bdef80',
+			'org.ow2.asm:asm:5.0.4:asm-5.0.4.jar:896618ed8ae62702521a78bc7be42b7c491a08e6920a15f89a3ecdec31e9a220',
+	]
+}
+
+// needed to make test output available to bramble-core and briar-core
+configurations {
+	testOutput.extendsFrom(testCompile)
+}
+task jarTest(type: Jar, dependsOn: testClasses) {
+	from sourceSets.test.output
+	classifier = 'test'
+}
+artifacts {
+	testOutput jarTest
+}
+
+// If a Java 6 JRE is available, check we're not using any Java 7 or 8 APIs
+tasks.withType(JavaCompile) {
+	useJava6StandardLibrary(it)
+}

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

@@ -1,11 +1,18 @@
-package org.briarproject.api;
+package org.briarproject.bramble.api;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.util.StringUtils;
 
 import java.util.Arrays;
 import java.util.Comparator;
 
+import javax.annotation.concurrent.ThreadSafe;
+
 /**
  * A wrapper around a byte array, to allow it to be stored in maps etc.
  */
+@ThreadSafe
+@NotNullByDefault
 public class Bytes implements Comparable<Bytes> {
 
 	public static final BytesComparator COMPARATOR = new BytesComparator();
@@ -47,6 +54,12 @@ public class Bytes implements Comparable<Bytes> {
 		return aBytes.length - bBytes.length;
 	}
 
+	@Override
+	public String toString() {
+		return getClass().getSimpleName() +
+				"(" + StringUtils.toHexString(getBytes()) + ")";
+	}
+
 	public static class BytesComparator implements Comparator<Bytes> {
 
 		@Override

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

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

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

@@ -1,12 +1,10 @@
-package org.briarproject.api;
+package org.briarproject.bramble.api;
 
 import java.util.Hashtable;
 import java.util.Map;
 
 public abstract class StringMap extends Hashtable<String, String> {
 
-	private static final long serialVersionUID = 2497176435908100448L;
-
 	protected StringMap(Map<String, String> m) {
 		super(m);
 	}

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

@@ -0,0 +1,20 @@
+package org.briarproject.bramble.api;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.ThreadSafe;
+
+@ThreadSafe
+@NotNullByDefault
+public abstract class UniqueId extends Bytes {
+
+	/**
+	 * The length of a unique identifier in bytes.
+	 */
+	public static final int LENGTH = 32;
+
+	protected UniqueId(byte[] id) {
+		super(id);
+		if (id.length != LENGTH) throw new IllegalArgumentException();
+	}
+}

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

@@ -1,8 +1,8 @@
-package org.briarproject.api.clients;
+package org.briarproject.bramble.api.client;
 
-import org.briarproject.api.data.BdfDictionary;
-import org.briarproject.api.nullsafety.NotNullByDefault;
-import org.briarproject.api.sync.MessageId;
+import org.briarproject.bramble.api.data.BdfDictionary;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.MessageId;
 
 import java.util.Collection;
 import java.util.Collections;
@@ -23,7 +23,7 @@ public class BdfMessageContext {
 	}
 
 	public BdfMessageContext(BdfDictionary dictionary) {
-		this(dictionary, Collections.<MessageId>emptyList());
+		this(dictionary, Collections.emptyList());
 	}
 
 	public BdfDictionary getDictionary() {

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

@@ -0,0 +1,66 @@
+package org.briarproject.bramble.api.client;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.data.MetadataEncoder;
+import org.briarproject.bramble.api.db.Metadata;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.Group;
+import org.briarproject.bramble.api.sync.InvalidMessageException;
+import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.sync.MessageContext;
+import org.briarproject.bramble.api.sync.ValidationManager.MessageValidator;
+import org.briarproject.bramble.api.system.Clock;
+
+import java.util.logging.Logger;
+
+import javax.annotation.concurrent.Immutable;
+
+import static org.briarproject.bramble.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
+import static org.briarproject.bramble.api.transport.TransportConstants.MAX_CLOCK_DIFFERENCE;
+
+@Immutable
+@NotNullByDefault
+public abstract class BdfMessageValidator implements MessageValidator {
+
+	protected static final Logger LOG =
+			Logger.getLogger(BdfMessageValidator.class.getName());
+
+	protected final ClientHelper clientHelper;
+	protected final MetadataEncoder metadataEncoder;
+	protected final Clock clock;
+
+	protected BdfMessageValidator(ClientHelper clientHelper,
+			MetadataEncoder metadataEncoder, Clock clock) {
+		this.clientHelper = clientHelper;
+		this.metadataEncoder = metadataEncoder;
+		this.clock = clock;
+	}
+
+	protected abstract BdfMessageContext validateMessage(Message m, Group g,
+			BdfList body) throws InvalidMessageException, FormatException;
+
+	@Override
+	public MessageContext validateMessage(Message m, Group g)
+			throws InvalidMessageException {
+		// Reject the message if it's too far in the future
+		long now = clock.currentTimeMillis();
+		if (m.getTimestamp() - now > MAX_CLOCK_DIFFERENCE) {
+			throw new InvalidMessageException(
+					"Timestamp is too far in the future");
+		}
+		byte[] raw = m.getRaw();
+		if (raw.length <= MESSAGE_HEADER_LENGTH) {
+			throw new InvalidMessageException("Message is too short");
+		}
+		try {
+			BdfList body = clientHelper.toList(raw, MESSAGE_HEADER_LENGTH,
+					raw.length - MESSAGE_HEADER_LENGTH);
+			BdfMessageContext result = validateMessage(m, g, body);
+			Metadata meta = metadataEncoder.encode(result.getDictionary());
+			return new MessageContext(meta, result.getDependencies());
+		} catch (FormatException e) {
+			throw new InvalidMessageException(e);
+		}
+	}
+}

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

@@ -1,14 +1,14 @@
-package org.briarproject.api.clients;
+package org.briarproject.bramble.api.client;
 
-import org.briarproject.api.FormatException;
-import org.briarproject.api.data.BdfDictionary;
-import org.briarproject.api.data.BdfList;
-import org.briarproject.api.db.DbException;
-import org.briarproject.api.db.Transaction;
-import org.briarproject.api.nullsafety.NotNullByDefault;
-import org.briarproject.api.sync.GroupId;
-import org.briarproject.api.sync.Message;
-import org.briarproject.api.sync.MessageId;
+import org.briarproject.bramble.api.FormatException;
+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.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.sync.MessageId;
 
 import java.security.GeneralSecurityException;
 import java.util.Map;
@@ -48,7 +48,8 @@ public interface ClientHelper {
 	BdfDictionary getGroupMetadataAsDictionary(Transaction txn, GroupId g)
 			throws DbException, FormatException;
 
-	BdfDictionary getMessageMetadataAsDictionary(MessageId m) throws DbException,
+	BdfDictionary getMessageMetadataAsDictionary(MessageId m)
+			throws DbException,
 			FormatException;
 
 	BdfDictionary getMessageMetadataAsDictionary(Transaction txn, MessageId m)

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

@@ -0,0 +1,29 @@
+package org.briarproject.bramble.api.client;
+
+import org.briarproject.bramble.api.contact.Contact;
+import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.ClientId;
+import org.briarproject.bramble.api.sync.Group;
+
+@NotNullByDefault
+public interface ContactGroupFactory {
+
+	/**
+	 * Creates a group that is not shared with any contacts.
+	 */
+	Group createLocalGroup(ClientId clientId);
+
+	/**
+	 * Creates a group for the given client to share with the given contact.
+	 */
+	Group createContactGroup(ClientId clientId, Contact contact);
+
+	/**
+	 * Creates a group for the given client to share between the given authors
+	 * identified by their AuthorIds.
+	 */
+	Group createContactGroup(ClientId clientId, AuthorId authorId1,
+			AuthorId authorId2);
+
+}

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

@@ -1,8 +1,13 @@
-package org.briarproject.api.contact;
+package org.briarproject.bramble.api.contact;
 
-import org.briarproject.api.identity.Author;
-import org.briarproject.api.identity.AuthorId;
+import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
 public class Contact {
 
 	private final ContactId id;

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

@@ -0,0 +1,20 @@
+package org.briarproject.bramble.api.contact;
+
+import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface ContactExchangeListener {
+
+	void contactExchangeSucceeded(Author remoteAuthor);
+
+	/**
+	 * The exchange failed because the contact already exists.
+	 */
+	void duplicateContact(Author remoteAuthor);
+
+	/**
+	 * A general failure.
+	 */
+	void contactExchangeFailed();
+}

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

@@ -0,0 +1,22 @@
+package org.briarproject.bramble.api.contact;
+
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.identity.LocalAuthor;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+
+/**
+ * A task for conducting a contact information exchange with a remote peer.
+ */
+@NotNullByDefault
+public interface ContactExchangeTask {
+
+	/**
+	 * Exchanges contact information with a remote peer.
+	 */
+	void startExchange(ContactExchangeListener listener,
+			LocalAuthor localAuthor, SecretKey masterSecret,
+			DuplexTransportConnection conn, TransportId transportId,
+			boolean alice);
+}

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

@@ -1,9 +1,15 @@
-package org.briarproject.api.contact;
+package org.briarproject.bramble.api.contact;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
 
 /**
  * Type-safe wrapper for an integer that uniquely identifies a contact within
  * the scope of a single node.
  */
+@Immutable
+@NotNullByDefault
 public class ContactId {
 
 	private final int id;

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

@@ -0,0 +1,104 @@
+package org.briarproject.bramble.api.contact;
+
+import org.briarproject.bramble.api.crypto.SecretKey;
+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.identity.AuthorId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.util.Collection;
+
+@NotNullByDefault
+public interface ContactManager {
+
+	/**
+	 * Registers a hook to be called whenever a contact is added.
+	 */
+	void registerAddContactHook(AddContactHook hook);
+
+	/**
+	 * Registers a hook to be called whenever a contact is removed.
+	 */
+	void registerRemoveContactHook(RemoveContactHook hook);
+
+	/**
+	 * Stores a contact within the given transaction associated with the given
+	 * local and remote pseudonyms, and returns an ID for the contact.
+	 */
+	ContactId addContact(Transaction txn, Author remote, AuthorId local,
+			SecretKey master, long timestamp, boolean alice, boolean verified,
+			boolean active) throws DbException;
+
+	/**
+	 * Stores a contact associated with the given local and remote pseudonyms,
+	 * and returns an ID for the contact.
+	 */
+	ContactId addContact(Author remote, AuthorId local,
+			SecretKey master, long timestamp, boolean alice, boolean verified,
+			boolean active) throws DbException;
+
+	/**
+	 * Returns the contact with the given ID.
+	 */
+	Contact getContact(ContactId c) throws DbException;
+
+	/**
+	 * Returns the contact with the given remoteAuthorId
+	 * that was added by the LocalAuthor with the given localAuthorId
+	 *
+	 * @throws org.briarproject.bramble.api.db.NoSuchContactException
+	 */
+	Contact getContact(AuthorId remoteAuthorId, AuthorId localAuthorId)
+			throws DbException;
+
+	/**
+	 * Returns the contact with the given remoteAuthorId
+	 * that was added by the LocalAuthor with the given localAuthorId
+	 *
+	 * @throws org.briarproject.bramble.api.db.NoSuchContactException
+	 */
+	Contact getContact(Transaction txn, AuthorId remoteAuthorId,
+			AuthorId localAuthorId) throws DbException;
+
+	/**
+	 * Returns all active contacts.
+	 */
+	Collection<Contact> getActiveContacts() throws DbException;
+
+	/**
+	 * Removes a contact and all associated state.
+	 */
+	void removeContact(ContactId c) throws DbException;
+
+	/**
+	 * Removes a contact and all associated state.
+	 */
+	void removeContact(Transaction txn, ContactId c) throws DbException;
+
+	/**
+	 * Marks a contact as active or inactive.
+	 */
+	void setContactActive(Transaction txn, ContactId c, boolean active)
+			throws DbException;
+
+	/**
+	 * Return true if a contact with this name and public key already exists
+	 */
+	boolean contactExists(Transaction txn, AuthorId remoteAuthorId,
+			AuthorId localAuthorId) throws DbException;
+
+	/**
+	 * Return true if a contact with this name and public key already exists
+	 */
+	boolean contactExists(AuthorId remoteAuthorId, AuthorId localAuthorId)
+			throws DbException;
+
+	interface AddContactHook {
+		void addingContact(Transaction txn, Contact c) throws DbException;
+	}
+
+	interface RemoveContactHook {
+		void removingContact(Transaction txn, Contact c) throws DbException;
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/contact/event/ContactAddedEvent.java

@@ -0,0 +1,31 @@
+package org.briarproject.bramble.api.contact.event;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that is broadcast when a contact is added.
+ */
+@Immutable
+@NotNullByDefault
+public class ContactAddedEvent extends Event {
+
+	private final ContactId contactId;
+	private final boolean active;
+
+	public ContactAddedEvent(ContactId contactId, boolean active) {
+		this.contactId = contactId;
+		this.active = active;
+	}
+
+	public ContactId getContactId() {
+		return contactId;
+	}
+
+	public boolean isActive() {
+		return active;
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/contact/event/ContactRemovedEvent.java

@@ -0,0 +1,25 @@
+package org.briarproject.bramble.api.contact.event;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that is broadcast when a contact is removed.
+ */
+@Immutable
+@NotNullByDefault
+public class ContactRemovedEvent extends Event {
+
+	private final ContactId contactId;
+
+	public ContactRemovedEvent(ContactId contactId) {
+		this.contactId = contactId;
+	}
+
+	public ContactId getContactId() {
+		return contactId;
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/contact/event/ContactStatusChangedEvent.java

@@ -0,0 +1,31 @@
+package org.briarproject.bramble.api.contact.event;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that is broadcast when a contact is marked active or inactive.
+ */
+@Immutable
+@NotNullByDefault
+public class ContactStatusChangedEvent extends Event {
+
+	private final ContactId contactId;
+	private final boolean active;
+
+	public ContactStatusChangedEvent(ContactId contactId, boolean active) {
+		this.contactId = contactId;
+		this.active = active;
+	}
+
+	public ContactId getContactId() {
+		return contactId;
+	}
+
+	public boolean isActive() {
+		return active;
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/contact/event/ContactVerifiedEvent.java

@@ -0,0 +1,26 @@
+package org.briarproject.bramble.api.contact.event;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that is broadcast when a contact is verified.
+ */
+@Immutable
+@NotNullByDefault
+public class ContactVerifiedEvent extends Event {
+
+	private final ContactId contactId;
+
+	public ContactVerifiedEvent(ContactId contactId) {
+		this.contactId = contactId;
+	}
+
+	public ContactId getContactId() {
+		return contactId;
+	}
+
+}

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

@@ -1,7 +1,7 @@
-package org.briarproject.api.crypto;
+package org.briarproject.bramble.api.crypto;
 
-import org.briarproject.api.TransportId;
-import org.briarproject.api.transport.TransportKeys;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.security.GeneralSecurityException;
 import java.security.SecureRandom;
@@ -10,10 +10,6 @@ public interface CryptoComponent {
 
 	SecretKey generateSecretKey();
 
-	MessageDigest getMessageDigest();
-
-	PseudoRandom getPseudoRandom(int seed1, int seed2);
-
 	SecureRandom getSecureRandom();
 
 	KeyPair generateAgreementKeyPair();
@@ -26,15 +22,6 @@ public interface CryptoComponent {
 
 	KeyParser getMessageKeyParser();
 
-	/** Generates a random invitation code. */
-	int generateBTInvitationCode();
-
-	/**
-	 * Derives a confirmation code from the given master secret.
-	 * @param alice whether the code is for use by Alice or Bob.
-	 */
-	int deriveBTConfirmationCode(SecretKey master, boolean alice);
-
 	/**
 	 * Derives a stream header key from the given master secret.
 	 * @param alice whether the key is for use by Alice or Bob.
@@ -139,7 +126,8 @@ public interface CryptoComponent {
 	TransportKeys rotateTransportKeys(TransportKeys k, long rotationPeriod);
 
 	/** Encodes the pseudo-random tag that is used to recognise a stream. */
-	void encodeTag(byte[] tag, SecretKey tagKey, long streamNumber);
+	void encodeTag(byte[] tag, SecretKey tagKey, int protocolVersion,
+			long streamNumber);
 
 	/**
 	 * Signs the given byte[] with the given PrivateKey.
@@ -164,8 +152,17 @@ 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 label specific to this hash to ensure that hashes
+	 *              calculated for distinct purposes don't collide.
 	 */
-	byte[] hash(byte[]... inputs);
+	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

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

@@ -1,4 +1,4 @@
-package org.briarproject.api.crypto;
+package org.briarproject.bramble.api.crypto;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.Target;

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

@@ -1,6 +1,14 @@
-package org.briarproject.api.crypto;
+package org.briarproject.bramble.api.crypto;
 
-/** A key pair consisting of a {@link PublicKey} and a {@link PrivateKey). */
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * A key pair consisting of a {@link PublicKey} and a {@link PrivateKey).
+ */
+@Immutable
+@NotNullByDefault
 public class KeyPair {
 
 	private final PublicKey publicKey;

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

@@ -1,7 +1,10 @@
-package org.briarproject.api.crypto;
+package org.briarproject.bramble.api.crypto;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.security.GeneralSecurityException;
 
+@NotNullByDefault
 public interface KeyParser {
 
 	PublicKey parsePublicKey(byte[] encodedKey) throws GeneralSecurityException;

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

@@ -1,11 +1,14 @@
-package org.briarproject.api.crypto;
+package org.briarproject.bramble.api.crypto;
 
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
 public interface PasswordStrengthEstimator {
 
 	float NONE = 0;
-	float WEAK = 0.4f;
-	float QUITE_WEAK = 0.6f;
-	float QUITE_STRONG = 0.8f;
+	float WEAK = 0.25f;
+	float QUITE_WEAK = 0.5f;
+	float QUITE_STRONG = 0.75f;
 	float STRONG = 1;
 
 	/**

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

@@ -0,0 +1,15 @@
+package org.briarproject.bramble.api.crypto;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+/**
+ * The private half of a public/private {@link KeyPair}.
+ */
+@NotNullByDefault
+public interface PrivateKey {
+
+	/**
+	 * Returns the encoded representation of this key.
+	 */
+	byte[] getEncoded();
+}

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

@@ -0,0 +1,15 @@
+package org.briarproject.bramble.api.crypto;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+/**
+ * The public half of a public/private {@link KeyPair}.
+ */
+@NotNullByDefault
+public interface PublicKey {
+
+	/**
+	 * Returns the encoded representation of this key.
+	 */
+	byte[] getEncoded();
+}

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

@@ -1,9 +1,14 @@
-package org.briarproject.api.crypto;
+package org.briarproject.bramble.api.crypto;
 
-/** A secret key used for encryption and/or authentication. */
+/**
+ * A secret key used for encryption and/or authentication.
+ */
 public class SecretKey {
 
-	public static final int LENGTH = 32; // Bytes
+	/**
+	 * The length of a secret key in bytes.
+	 */
+	public static final int LENGTH = 32;
 
 	private final byte[] key;
 

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

@@ -1,13 +1,17 @@
-package org.briarproject.api.crypto;
+package org.briarproject.bramble.api.crypto;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.io.IOException;
 
+@NotNullByDefault
 public interface StreamDecrypter {
 
 	/**
 	 * Reads a frame, decrypts its payload into the given buffer and returns
 	 * the payload length, or -1 if no more frames can be read from the stream.
-	 * @throws java.io.IOException if an error occurs while reading the frame,
+	 *
+	 * @throws IOException if an error occurs while reading the frame,
 	 * or if authenticated decryption fails.
 	 */
 	int readFrame(byte[] payload) throws IOException;

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

@@ -0,0 +1,22 @@
+package org.briarproject.bramble.api.crypto;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.transport.StreamContext;
+
+import java.io.InputStream;
+
+@NotNullByDefault
+public interface StreamDecrypterFactory {
+
+	/**
+	 * Creates a {@link StreamDecrypter} for decrypting a transport stream.
+	 */
+	StreamDecrypter createStreamDecrypter(InputStream in, StreamContext ctx);
+
+	/**
+	 * Creates a {@link StreamDecrypter} for decrypting a contact exchange
+	 * stream.
+	 */
+	StreamDecrypter createContactExchangeStreamDecrypter(InputStream in,
+			SecretKey headerKey);
+}

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

@@ -0,0 +1,20 @@
+package org.briarproject.bramble.api.crypto;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.io.IOException;
+
+@NotNullByDefault
+public interface StreamEncrypter {
+
+	/**
+	 * Encrypts the given frame and writes it to the stream.
+	 */
+	void writeFrame(byte[] payload, int payloadLength, int paddingLength,
+			boolean finalFrame) throws IOException;
+
+	/**
+	 * Flushes the stream.
+	 */
+	void flush() throws IOException;
+}

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

@@ -0,0 +1,22 @@
+package org.briarproject.bramble.api.crypto;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.transport.StreamContext;
+
+import java.io.OutputStream;
+
+@NotNullByDefault
+public interface StreamEncrypterFactory {
+
+	/**
+	 * Creates a {@link StreamEncrypter} for encrypting a transport stream.
+	 */
+	StreamEncrypter createStreamEncrypter(OutputStream out, StreamContext ctx);
+
+	/**
+	 * Creates a {@link StreamEncrypter} for encrypting a contact exchange
+	 * stream.
+	 */
+	StreamEncrypter createContactExchangeStreamDecrypter(OutputStream out,
+			SecretKey headerKey);
+}

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

@@ -1,14 +1,17 @@
-package org.briarproject.api.data;
+package org.briarproject.bramble.api.data;
 
-import org.briarproject.api.Bytes;
-import org.briarproject.api.FormatException;
+import org.briarproject.bramble.api.Bytes;
+import org.briarproject.bramble.api.FormatException;
 
 import java.util.Map;
-import java.util.concurrent.ConcurrentSkipListMap;
+import java.util.Map.Entry;
+import java.util.TreeMap;
 
 import javax.annotation.Nullable;
+import javax.annotation.concurrent.NotThreadSafe;
 
-public class BdfDictionary extends ConcurrentSkipListMap<String, Object> {
+@NotThreadSafe
+public class BdfDictionary extends TreeMap<String, Object> {
 
 	public static final Object NULL_VALUE = new Object();
 

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

@@ -1,7 +1,13 @@
-package org.briarproject.api.data;
+package org.briarproject.bramble.api.data;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.util.Map.Entry;
 
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
 public class BdfEntry implements Entry<String, Object>, Comparable<BdfEntry> {
 
 	private final String key;

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

@@ -1,16 +1,19 @@
-package org.briarproject.api.data;
+package org.briarproject.bramble.api.data;
 
-import org.briarproject.api.Bytes;
-import org.briarproject.api.FormatException;
-import org.jetbrains.annotations.Nullable;
+import org.briarproject.bramble.api.Bytes;
+import org.briarproject.bramble.api.FormatException;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
-import java.util.Vector;
 
-import static org.briarproject.api.data.BdfDictionary.NULL_VALUE;
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.NotThreadSafe;
 
-public class BdfList extends Vector<Object> {
+import static org.briarproject.bramble.api.data.BdfDictionary.NULL_VALUE;
+
+@NotThreadSafe
+public class BdfList extends ArrayList<Object> {
 
 	/**
 	 * Factory method for constructing lists inline.

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

@@ -1,49 +1,75 @@
-package org.briarproject.api.data;
+package org.briarproject.bramble.api.data;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.io.IOException;
 
+@NotNullByDefault
 public interface BdfReader {
 
 	int DEFAULT_NESTED_LIMIT = 5;
 
 	boolean eof() throws IOException;
+
 	void close() throws IOException;
 
 	boolean hasNull() throws IOException;
+
 	void readNull() throws IOException;
+
 	void skipNull() throws IOException;
 
 	boolean hasBoolean() throws IOException;
+
 	boolean readBoolean() throws IOException;
+
 	void skipBoolean() throws IOException;
 
 	boolean hasLong() throws IOException;
+
 	long readLong() throws IOException;
+
 	void skipLong() throws IOException;
 
 	boolean hasDouble() throws IOException;
+
 	double readDouble() throws IOException;
+
 	void skipDouble() throws IOException;
 
 	boolean hasString() throws IOException;
+
 	String readString(int maxLength) throws IOException;
+
 	void skipString() throws IOException;
 
 	boolean hasRaw() throws IOException;
+
 	byte[] readRaw(int maxLength) throws IOException;
+
 	void skipRaw() throws IOException;
 
 	boolean hasList() throws IOException;
+
 	BdfList readList() throws IOException;
+
 	void readListStart() throws IOException;
+
 	boolean hasListEnd() throws IOException;
+
 	void readListEnd() throws IOException;
+
 	void skipList() throws IOException;
 
 	boolean hasDictionary() throws IOException;
+
 	BdfDictionary readDictionary() throws IOException;
+
 	void readDictionaryStart() throws IOException;
+
 	boolean hasDictionaryEnd() throws IOException;
+
 	void readDictionaryEnd() throws IOException;
+
 	void skipDictionary() throws IOException;
 }

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

@@ -1,7 +1,10 @@
-package org.briarproject.api.data;
+package org.briarproject.bramble.api.data;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.io.InputStream;
 
+@NotNullByDefault
 public interface BdfReaderFactory {
 
 	BdfReader createReader(InputStream in);

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

@@ -1,4 +1,4 @@
-package org.briarproject.api.data;
+package org.briarproject.bramble.api.data;
 
 import java.io.IOException;
 import java.util.Collection;
@@ -7,20 +7,30 @@ import java.util.Map;
 public interface BdfWriter {
 
 	void flush() throws IOException;
+
 	void close() throws IOException;
 
 	void writeNull() throws IOException;
+
 	void writeBoolean(boolean b) throws IOException;
+
 	void writeLong(long l) throws IOException;
+
 	void writeDouble(double d) throws IOException;
+
 	void writeString(String s) throws IOException;
+
 	void writeRaw(byte[] b) throws IOException;
 
 	void writeList(Collection<?> c) throws IOException;
+
 	void writeListStart() throws IOException;
+
 	void writeListEnd() throws IOException;
 
 	void writeDictionary(Map<?, ?> m) throws IOException;
+
 	void writeDictionaryStart() throws IOException;
+
 	void writeDictionaryEnd() throws IOException;
 }

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

@@ -0,0 +1,11 @@
+package org.briarproject.bramble.api.data;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.io.OutputStream;
+
+@NotNullByDefault
+public interface BdfWriterFactory {
+
+	BdfWriter createWriter(OutputStream out);
+}

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

@@ -0,0 +1,11 @@
+package org.briarproject.bramble.api.data;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.db.Metadata;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface MetadataEncoder {
+
+	Metadata encode(BdfDictionary d) throws FormatException;
+}

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

@@ -0,0 +1,11 @@
+package org.briarproject.bramble.api.data;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.db.Metadata;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface MetadataParser {
+
+	BdfDictionary parse(Metadata m) throws FormatException;
+}

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/ContactExistsException.java

@@ -1,9 +1,8 @@
-package org.briarproject.api.db;
+package org.briarproject.bramble.api.db;
 
 /**
  * Thrown when a duplicate contact is added to the database. This exception may
  * occur due to concurrent updates and does not indicate a database error.
  */
 public class ContactExistsException extends DbException {
-
 }

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

@@ -0,0 +1,7 @@
+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

@@ -0,0 +1,8 @@
+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

@@ -1,40 +1,49 @@
-package org.briarproject.api.db;
+package org.briarproject.bramble.api.db;
 
-import org.briarproject.api.TransportId;
-import org.briarproject.api.contact.Contact;
-import org.briarproject.api.contact.ContactId;
-import org.briarproject.api.identity.Author;
-import org.briarproject.api.identity.AuthorId;
-import org.briarproject.api.identity.LocalAuthor;
-import org.briarproject.api.settings.Settings;
-import org.briarproject.api.sync.Ack;
-import org.briarproject.api.sync.ClientId;
-import org.briarproject.api.sync.Group;
-import org.briarproject.api.sync.Group.Visibility;
-import org.briarproject.api.sync.GroupId;
-import org.briarproject.api.sync.Message;
-import org.briarproject.api.sync.MessageId;
-import org.briarproject.api.sync.MessageStatus;
-import org.briarproject.api.sync.Offer;
-import org.briarproject.api.sync.Request;
-import org.briarproject.api.transport.TransportKeys;
-import org.jetbrains.annotations.Nullable;
+import org.briarproject.bramble.api.contact.Contact;
+import org.briarproject.bramble.api.contact.ContactId;
+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.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.settings.Settings;
+import org.briarproject.bramble.api.sync.Ack;
+import org.briarproject.bramble.api.sync.ClientId;
+import org.briarproject.bramble.api.sync.Group;
+import org.briarproject.bramble.api.sync.Group.Visibility;
+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.api.sync.MessageStatus;
+import org.briarproject.bramble.api.sync.Offer;
+import org.briarproject.bramble.api.sync.Request;
+import org.briarproject.bramble.api.sync.ValidationManager;
+import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.util.Collection;
 import java.util.Map;
 
-import static org.briarproject.api.sync.ValidationManager.State;
+import javax.annotation.Nullable;
+
+import static org.briarproject.bramble.api.sync.ValidationManager.State;
 
 /**
  * Encapsulates the database implementation and exposes high-level operations
  * to other components.
  */
+@NotNullByDefault
 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() throws DbException;
+	boolean open(@Nullable MigrationListener listener) throws DbException;
 
 	/**
 	 * Waits for any open transactions to finish and closes the database.
@@ -118,8 +127,9 @@ public interface DatabaseComponent {
 			throws DbException;
 
 	/**
-	 * Deletes the message with the given ID. The message ID and any other
-	 * associated data are not deleted.
+	 * Deletes the message with the given ID. Unlike
+	 * {@link #removeMessage(Transaction, MessageId)}, the message ID and any
+	 * other associated data are not deleted.
 	 */
 	void deleteMessage(Transaction txn, MessageId m) throws DbException;
 
@@ -249,31 +259,30 @@ public interface DatabaseComponent {
 	Collection<LocalAuthor> getLocalAuthors(Transaction txn) throws DbException;
 
 	/**
-	 * Returns the IDs of any messages that need to be validated by the given
-	 * client.
+	 * Returns the IDs of any messages that need to be validated.
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<MessageId> getMessagesToValidate(Transaction txn, ClientId c)
+	Collection<MessageId> getMessagesToValidate(Transaction txn)
 			throws DbException;
 
 	/**
-	 * Returns the IDs of any messages that are valid but pending delivery due
-	 * to dependencies on other messages for the given client.
+	 * Returns the IDs of any messages that are pending delivery due to
+	 * dependencies on other messages.
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<MessageId> getPendingMessages(Transaction txn, ClientId c)
+	Collection<MessageId> getPendingMessages(Transaction txn)
 			throws DbException;
 
 	/**
-	 * Returns the IDs of any messages from the given client
-	 * that have a shared dependent, but are still not shared themselves.
+	 * Returns the IDs of any messages that have shared dependents but have
+	 * not yet been shared themselves.
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<MessageId> getMessagesToShare(Transaction txn,
-			ClientId c) throws DbException;
+	Collection<MessageId> getMessagesToShare(Transaction txn)
+			throws DbException;
 
 	/**
 	 * Returns the message with the given ID, in serialised form, or null if
@@ -330,10 +339,10 @@ public interface DatabaseComponent {
 
 	/**
 	 * Returns the IDs and states of all dependencies of the given message.
-	 * Missing dependencies have the state {@link
-	 * org.briarproject.api.sync.ValidationManager.State UNKNOWN}.
-	 * Dependencies in other groups have the state {@link
-	 * org.briarproject.api.sync.ValidationManager.State INVALID}.
+	 * Missing dependencies have the state
+	 * {@link ValidationManager.State UNKNOWN}.
+	 * Dependencies in other groups have the state
+	 * {@link ValidationManager.State INVALID}.
 	 * Note that these states are not set on the dependencies themselves; the
 	 * returned states should only be taken in the context of the given message.
 	 * <p/>
@@ -368,6 +377,16 @@ 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/>
@@ -448,6 +467,11 @@ public interface DatabaseComponent {
 	 */
 	void removeLocalAuthor(Transaction txn, AuthorId a) throws DbException;
 
+	/**
+	 * Removes a message (and all associated state) from the database.
+	 */
+	void removeMessage(Transaction txn, MessageId m) throws DbException;
+
 	/**
 	 * Removes a transport (and all associated state) from the database.
 	 */

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

@@ -1,9 +1,13 @@
-package org.briarproject.api.db;
+package org.briarproject.bramble.api.db;
 
-import org.briarproject.api.crypto.SecretKey;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.io.File;
 
+import javax.annotation.Nullable;
+
+@NotNullByDefault
 public interface DatabaseConfig {
 
 	boolean databaseExists();
@@ -12,10 +16,12 @@ public interface DatabaseConfig {
 
 	void setEncryptionKey(SecretKey key);
 
+	@Nullable
 	SecretKey getEncryptionKey();
 
 	void setLocalAuthorName(String nickname);
 
+	@Nullable
 	String getLocalAuthorName();
 
 	long getMaxSize();

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

@@ -1,4 +1,4 @@
-package org.briarproject.api.db;
+package org.briarproject.bramble.api.db;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.Target;
@@ -20,6 +20,7 @@ import static java.lang.annotation.RetentionPolicy.RUNTIME;
  * discarded.
  */
 @Qualifier
-@Target({ FIELD, METHOD, PARAMETER })
+@Target({FIELD, METHOD, PARAMETER})
 @Retention(RUNTIME)
-public @interface DatabaseExecutor {}
+public @interface DatabaseExecutor {
+}

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

@@ -1,8 +1,7 @@
-package org.briarproject.api.db;
+package org.briarproject.bramble.api.db;
 
 /**
  * Thrown when a database operation is attempted and the database is closed.
  */
 public class DbClosedException extends DbException {
-
 }

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

@@ -1,4 +1,4 @@
-package org.briarproject.api.db;
+package org.briarproject.bramble.api.db;
 
 public class DbException extends Exception {
 

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

@@ -0,0 +1,14 @@
+package org.briarproject.bramble.api.db;
+
+import java.util.TreeMap;
+
+import javax.annotation.concurrent.NotThreadSafe;
+
+@NotThreadSafe
+public class Metadata extends TreeMap<String, byte[]> {
+
+	/**
+	 * Special value to indicate that a key is being removed.
+	 */
+	public static final byte[] REMOVE = new byte[0];
+}

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

@@ -0,0 +1,11 @@
+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/db/NoSuchContactException.java

@@ -1,4 +1,4 @@
-package org.briarproject.api.db;
+package org.briarproject.bramble.api.db;
 
 /**
  * Thrown when a database operation is attempted for a contact that is not in
@@ -6,5 +6,4 @@ package org.briarproject.api.db;
  * not indicate a database error.
  */
 public class NoSuchContactException extends DbException {
-
 }

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

@@ -1,4 +1,4 @@
-package org.briarproject.api.db;
+package org.briarproject.bramble.api.db;
 
 /**
  * Thrown when a database operation is attempted for a group that is not in the
@@ -6,5 +6,4 @@ package org.briarproject.api.db;
  * indicate a database error.
  */
 public class NoSuchGroupException extends DbException {
-
 }

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

@@ -1,4 +1,4 @@
-package org.briarproject.api.db;
+package org.briarproject.bramble.api.db;
 
 /**
  * Thrown when a database operation is attempted for a pseudonym that is not in
@@ -6,5 +6,4 @@ package org.briarproject.api.db;
  * not indicate a database error.
  */
 public class NoSuchLocalAuthorException extends DbException {
-
 }

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

@@ -1,4 +1,4 @@
-package org.briarproject.api.db;
+package org.briarproject.bramble.api.db;
 
 /**
  * Thrown when a database operation is attempted for a message that is not in
@@ -6,5 +6,4 @@ package org.briarproject.api.db;
  * not indicate a database error.
  */
 public class NoSuchMessageException extends DbException {
-
 }

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

@@ -1,4 +1,4 @@
-package org.briarproject.api.db;
+package org.briarproject.bramble.api.db;
 
 /**
  * Thrown when a database operation is attempted for a transport that is not in
@@ -6,5 +6,4 @@ package org.briarproject.api.db;
  * not indicate a database error.
  */
 public class NoSuchTransportException extends DbException {
-
 }

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

@@ -1,14 +1,17 @@
-package org.briarproject.api.db;
+package org.briarproject.bramble.api.db;
 
-import org.briarproject.api.event.Event;
+import org.briarproject.bramble.api.event.Event;
 
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
+import javax.annotation.concurrent.NotThreadSafe;
+
 /**
  * A wrapper around a database transaction. Transactions are not thread-safe.
  */
+@NotThreadSafe
 public class Transaction {
 
 	private final Object txn;
@@ -42,7 +45,7 @@ public class Transaction {
 	 * committed.
 	 */
 	public void attach(Event e) {
-		if (events == null) events = new ArrayList<Event>();
+		if (events == null) events = new ArrayList<>();
 		events.add(e);
 	}
 

bramble-api/src/main/java/org/briarproject/bramble/api/event/Event.java

@@ -0,0 +1,7 @@
+package org.briarproject.bramble.api.event;
+
+/**
+ * An abstract superclass for events.
+ */
+public abstract class Event {
+}

bramble-api/src/main/java/org/briarproject/bramble/api/event/EventBus.java

@@ -0,0 +1,22 @@
+package org.briarproject.bramble.api.event;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface EventBus {
+
+	/**
+	 * Adds a listener to be notified when events occur.
+	 */
+	void addListener(EventListener l);
+
+	/**
+	 * Removes a listener.
+	 */
+	void removeListener(EventListener l);
+
+	/**
+	 * Notifies all listeners of an event.
+	 */
+	void broadcast(Event e);
+}

bramble-api/src/main/java/org/briarproject/bramble/api/event/EventListener.java

@@ -0,0 +1,16 @@
+package org.briarproject.bramble.api.event;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+/**
+ * An interface for receiving notifications when events occur.
+ */
+@NotNullByDefault
+public interface EventListener {
+
+	/**
+	 * Called when an event is broadcast. Implementations of this method must
+	 * not block.
+	 */
+	void eventOccurred(Event e);
+}

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

@@ -1,11 +1,21 @@
-package org.briarproject.api.identity;
+package org.briarproject.bramble.api.identity;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.io.UnsupportedEncodingException;
 
-/** A pseudonym for a user. */
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * A pseudonym for a user.
+ */
+@Immutable
+@NotNullByDefault
 public class Author {
 
-	public enum Status { ANONYMOUS, UNKNOWN, UNVERIFIED, VERIFIED, OURSELVES }
+	public enum Status {
+		NONE, ANONYMOUS, UNKNOWN, UNVERIFIED, VERIFIED, OURSELVES
+	}
 
 	private final AuthorId id;
 	private final String name;
@@ -25,17 +35,23 @@ public class Author {
 		this.publicKey = publicKey;
 	}
 
-	/** Returns the author's unique identifier. */
+	/**
+	 * Returns the author's unique identifier.
+	 */
 	public AuthorId getId() {
 		return id;
 	}
 
-	/** Returns the author's name. */
+	/**
+	 * Returns the author's name.
+	 */
 	public String getName() {
 		return name;
 	}
 
-	/** Returns the public key used to verify the pseudonym's signatures. */
+	/**
+	 * Returns the public key used to verify the pseudonym's signatures.
+	 */
 	public byte[] getPublicKey() {
 		return publicKey;
 	}

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

@@ -1,8 +1,10 @@
-package org.briarproject.api.identity;
+package org.briarproject.bramble.api.identity;
 
 public interface AuthorConstants {
 
-	/** The maximum length of an author's name in UTF-8 bytes. */
+	/**
+	 * The maximum length of an author's name in UTF-8 bytes.
+	 */
 	int MAX_AUTHOR_NAME_LENGTH = 50;
 
 	/**

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

@@ -1,5 +1,8 @@
-package org.briarproject.api.identity;
+package org.briarproject.bramble.api.identity;
 
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
 public interface AuthorFactory {
 
 	Author createAuthor(String name, byte[] publicKey);

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

@@ -1,20 +1,22 @@
-package org.briarproject.api.identity;
+package org.briarproject.bramble.api.identity;
 
-import org.briarproject.api.UniqueId;
+import org.briarproject.bramble.api.UniqueId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
-import java.nio.charset.Charset;
+import javax.annotation.concurrent.ThreadSafe;
 
 /**
  * Type-safe wrapper for a byte array that uniquely identifies an
- * {@link org.briarproject.api.identity.Author Author}.
+ * {@link Author}.
  */
+@ThreadSafe
+@NotNullByDefault
 public class AuthorId extends UniqueId {
 
 	/**
 	 * Label for hashing authors to calculate their identities.
 	 */
-	public static final byte[] LABEL =
-			"AUTHOR_ID".getBytes(Charset.forName("US-ASCII"));
+	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/IdentityManager.java

@@ -0,0 +1,38 @@
+package org.briarproject.bramble.api.identity;
+
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.identity.Author.Status;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface IdentityManager {
+
+	/**
+	 * Stores the local pseudonym.
+	 */
+	void registerLocalAuthor(LocalAuthor a) throws DbException;
+
+	/**
+	 * Returns the cached main local identity, non-blocking, or loads it from
+	 * the db, blocking
+	 */
+	LocalAuthor getLocalAuthor() throws DbException;
+
+	/**
+	 * Returns the cached main local identity, non-blocking, or loads it from
+	 * the db, blocking, within the given Transaction.
+	 */
+	LocalAuthor getLocalAuthor(Transaction txn) throws DbException;
+
+	/**
+	 * Returns the trust-level status of the author
+	 */
+	Status getAuthorStatus(AuthorId a) throws DbException;
+
+	/**
+	 * Returns the trust-level status of the author
+	 */
+	Status getAuthorStatus(Transaction txn, AuthorId a) throws DbException;
+
+}

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

@@ -1,6 +1,14 @@
-package org.briarproject.api.identity;
+package org.briarproject.bramble.api.identity;
 
-/** A pseudonym for the local user. */
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * A pseudonym for the local user.
+ */
+@Immutable
+@NotNullByDefault
 public class LocalAuthor extends Author {
 
 	private final byte[] privateKey;
@@ -13,7 +21,9 @@ public class LocalAuthor extends Author {
 		this.created = created;
 	}
 
-	/**  Returns the private key used to generate the pseudonym's signatures. */
+	/**
+	 * Returns the private key used to generate the pseudonym's signatures.
+	 */
 	public byte[] getPrivateKey() {
 		return privateKey;
 	}

bramble-api/src/main/java/org/briarproject/bramble/api/identity/event/LocalAuthorAddedEvent.java

@@ -0,0 +1,25 @@
+package org.briarproject.bramble.api.identity.event;
+
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that is broadcast when a local pseudonym is added.
+ */
+@Immutable
+@NotNullByDefault
+public class LocalAuthorAddedEvent extends Event {
+
+	private final AuthorId authorId;
+
+	public LocalAuthorAddedEvent(AuthorId authorId) {
+		this.authorId = authorId;
+	}
+
+	public AuthorId getAuthorId() {
+		return authorId;
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/identity/event/LocalAuthorRemovedEvent.java

@@ -0,0 +1,25 @@
+package org.briarproject.bramble.api.identity.event;
+
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that is broadcast when a local pseudonym is removed.
+ */
+@Immutable
+@NotNullByDefault
+public class LocalAuthorRemovedEvent extends Event {
+
+	private final AuthorId authorId;
+
+	public LocalAuthorRemovedEvent(AuthorId authorId) {
+		this.authorId = authorId;
+	}
+
+	public AuthorId getAuthorId() {
+		return authorId;
+	}
+}