@GuardedBy annotations.

.gitlab-ci.yml

@@ -1,11 +1,6 @@
 image: briar/ci-image-android:latest
 
-stages:
-- test
-- check_reproducibility
-
 test:
-  stage: test
   before_script:
     - set -e
     - export GRADLE_USER_HOME=$PWD/.gradle
@@ -17,7 +12,7 @@ test:
 
   script:
     - ./gradlew --no-daemon -Djava.security.egd=file:/dev/urandom animalSnifferMain animalSnifferTest
-    - ./gradlew --no-daemon -Djava.security.egd=file:/dev/urandom check compileOfficialDebugAndroidTestSources compileScreenshotDebugAndroidTestSources
+    - ./gradlew --no-daemon -Djava.security.egd=file:/dev/urandom test
 
   after_script:
     # these file change every time but should not be cached
@@ -26,7 +21,6 @@ test:
 
 
 test_reproducible:
-  stage: check_reproducibility
   script:
     - "curl -X POST -F token=${RELEASE_CHECK_TOKEN} -F ref=master -F variables[RELEASE_TAG]=${CI_COMMIT_REF_NAME} https://code.briarproject.org/api/v4/projects/61/trigger/pipeline"
   only:

.idea/codeStyles/Project.xml

@@ -1,10 +1,16 @@
 <component name="ProjectCodeStyleConfiguration">
   <code_scheme name="Project" version="173">
+    <option name="RIGHT_MARGIN" value="100" />
     <AndroidXmlCodeStyleSettings>
-      <option name="ARRANGEMENT_SETTINGS_MIGRATED_TO_191" value="true" />
+      <option name="USE_CUSTOM_SETTINGS" value="true" />
     </AndroidXmlCodeStyleSettings>
     <JavaCodeStyleSettings>
       <option name="ANNOTATION_PARAMETER_WRAP" value="1" />
+      <option name="CLASS_COUNT_TO_USE_IMPORT_ON_DEMAND" value="99" />
+      <option name="NAMES_COUNT_TO_USE_IMPORT_ON_DEMAND" value="99" />
+      <option name="PACKAGES_TO_USE_IMPORT_ON_DEMAND">
+        <value />
+      </option>
       <option name="IMPORT_LAYOUT_TABLE">
         <value>
           <package name="android" withSubpackages="true" static="false" />
@@ -33,6 +39,31 @@
     <JetCodeStyleSettings>
       <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
     </JetCodeStyleSettings>
+    <Objective-C-extensions>
+      <file>
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Import" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Macro" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Typedef" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Enum" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Constant" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Global" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Struct" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="FunctionPredecl" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Function" />
+      </file>
+      <class>
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Property" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Synthesize" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="InitMethod" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="StaticMethod" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="InstanceMethod" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="DeallocMethod" />
+      </class>
+      <extensions>
+        <pair source="cpp" header="h" fileNamingConvention="NONE" />
+        <pair source="c" header="h" fileNamingConvention="NONE" />
+      </extensions>
+    </Objective-C-extensions>
     <XML>
       <option name="XML_LEGACY_SETTINGS_IMPORTED" value="true" />
     </XML>
@@ -71,6 +102,7 @@
       </indentOptions>
     </codeStyleSettings>
     <codeStyleSettings language="XML">
+      <option name="FORCE_REARRANGE_MODE" value="1" />
       <indentOptions>
         <option name="CONTINUATION_INDENT_SIZE" value="4" />
         <option name="USE_TAB_CHARACTER" value="true" />
@@ -83,8 +115,7 @@
               <match>
                 <AND>
                   <NAME>xmlns:android</NAME>
-                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>Namespace:</XML_NAMESPACE>
-                  <XML_NAMESPACE>^$</XML_NAMESPACE>
                 </AND>
               </match>
             </rule>
@@ -94,8 +125,7 @@
               <match>
                 <AND>
                   <NAME>xmlns:.*</NAME>
-                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>Namespace:</XML_NAMESPACE>
-                  <XML_NAMESPACE>^$</XML_NAMESPACE>
                 </AND>
               </match>
               <order>BY_NAME</order>
@@ -106,7 +136,6 @@
               <match>
                 <AND>
                   <NAME>.*:id</NAME>
-                  <XML_ATTRIBUTE />
                   <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
                 </AND>
               </match>
@@ -117,7 +146,6 @@
               <match>
                 <AND>
                   <NAME>.*:name</NAME>
-                  <XML_ATTRIBUTE />
                   <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
                 </AND>
               </match>
@@ -128,7 +156,6 @@
               <match>
                 <AND>
                   <NAME>name</NAME>
-                  <XML_ATTRIBUTE />
                   <XML_NAMESPACE>^$</XML_NAMESPACE>
                 </AND>
               </match>
@@ -139,7 +166,6 @@
               <match>
                 <AND>
                   <NAME>style</NAME>
-                  <XML_ATTRIBUTE />
                   <XML_NAMESPACE>^$</XML_NAMESPACE>
                 </AND>
               </match>
@@ -150,7 +176,6 @@
               <match>
                 <AND>
                   <NAME>.*</NAME>
-                  <XML_ATTRIBUTE />
                   <XML_NAMESPACE>^$</XML_NAMESPACE>
                 </AND>
               </match>
@@ -161,12 +186,64 @@
             <rule>
               <match>
                 <AND>
-                  <NAME>.*</NAME>
+                  <NAME>.*:layout_width</NAME>
-                  <XML_ATTRIBUTE />
                   <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
                 </AND>
               </match>
-              <order>ANDROID_ATTRIBUTE_ORDER</order>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*:layout_height</NAME>
+                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*:layout_.*</NAME>
+                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
+                </AND>
+              </match>
+              <order>BY_NAME</order>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*:width</NAME>
+                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
+                </AND>
+              </match>
+              <order>BY_NAME</order>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*:height</NAME>
+                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
+                </AND>
+              </match>
+              <order>BY_NAME</order>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*</NAME>
+                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
+                </AND>
+              </match>
+              <order>BY_NAME</order>
             </rule>
           </section>
           <section>
@@ -174,7 +251,6 @@
               <match>
                 <AND>
                   <NAME>.*</NAME>
-                  <XML_ATTRIBUTE />
                   <XML_NAMESPACE>.*</XML_NAMESPACE>
                 </AND>
               </match>

.idea/runConfigurations/All_in_briar_headless.xml

@@ -0,0 +1,20 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All in briar-headless" type="AndroidJUnit" factoryName="Android JUnit" nameIsGenerated="true">
+    <module name="briar-headless" />
+    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
+    <option name="ALTERNATIVE_JRE_PATH" />
+    <option name="PACKAGE_NAME" value="org.briarproject.briar.headless" />
+    <option name="MAIN_CLASS_NAME" value="" />
+    <option name="METHOD_NAME" value="" />
+    <option name="TEST_OBJECT" value="package" />
+    <option name="VM_PARAMETERS" value="" />
+    <option name="PARAMETERS" value="" />
+    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/briar-headless" />
+    <option name="PASS_PARENT_ENVS" value="true" />
+    <option name="TEST_SEARCH_SCOPE">
+      <value defaultName="singleModule" />
+    </option>
+    <patterns />
+    <method />
+  </configuration>
+</component>

.idea/runConfigurations/All_tests.xml

@@ -1,20 +1,30 @@
 <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="$PROJECT_DIR$/briar-android" />
+    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/briar-android" />
-    <method v="2">
+    <option name="ENV_VARIABLES" />
-      <option name="Android.Gradle.BeforeRunTask" enabled="true" />
+    <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-android" run_configuration_type="AndroidJUnit" />
       <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in bramble-java" run_configuration_type="AndroidJUnit" />
       <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in briar-core" run_configuration_type="AndroidJUnit" />
-      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in briar-headless" run_configuration_type="AndroidJUnit" />
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All in briar-headless" run_configuration_type="AndroidJUnit" />
     </method>
   </configuration>
 </component>

.idea/runConfigurations/All_tests_in_briar_headless.xml

@@ -1,15 +0,0 @@
-<component name="ProjectRunConfigurationManager">
-  <configuration default="false" name="All tests in briar-headless" type="AndroidJUnit" factoryName="Android JUnit">
-    <module name="briar-headless" />
-    <option name="PACKAGE_NAME" value="org.briarproject.briar.headless" />
-    <option name="MAIN_CLASS_NAME" value="" />
-    <option name="METHOD_NAME" value="" />
-    <option name="TEST_OBJECT" value="package" />
-    <option name="VM_PARAMETERS" />
-    <option name="PARAMETERS" value="" />
-    <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$/briar-headless" />
-    <method v="2">
-      <option name="Android.Gradle.BeforeRunTask" enabled="true" />
-    </method>
-  </configuration>
-</component>

bramble-android/build.gradle

@@ -5,31 +5,23 @@ apply plugin: 'witness'
 apply from: 'witness.gradle'
 
 android {
-	compileSdkVersion 29
+	compileSdkVersion 28
-	buildToolsVersion '29.0.2'
+	buildToolsVersion '28.0.3'
 
 	defaultConfig {
-		minSdkVersion 16
+		minSdkVersion 14
-		targetSdkVersion 28
+		targetSdkVersion 26
-		versionCode 10205
+		versionCode 10105
-		versionName "1.2.5"
+		versionName "1.1.5"
 		consumerProguardFiles 'proguard-rules.txt'
 
-		testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+		testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
 	}
 
 	compileOptions {
 		sourceCompatibility JavaVersion.VERSION_1_8
 		targetCompatibility JavaVersion.VERSION_1_8
 	}
-
-	lintOptions {
-		// FIXME
-		warning "LintError"
-		warning "InvalidPackage"
-		warning "MissingPermission"
-		warning "InlinedApi", "ObsoleteSdkInt", "Override", "NewApi", "UnusedAttribute"
-	}
 }
 
 configurations {
@@ -38,10 +30,10 @@ configurations {
 
 dependencies {
 	implementation project(path: ':bramble-core', configuration: 'default')
-	tor 'org.briarproject:tor-android:0.3.5.9@zip'
+	tor 'org.briarproject:tor-android:0.3.4.8@zip'
-	tor 'org.briarproject:obfs4proxy-android:0.0.11-2@zip'
+	tor 'org.briarproject:obfs4proxy-android:0.0.7@zip'
 
-	annotationProcessor 'com.google.dagger:dagger-compiler:2.24'
+	annotationProcessor 'com.google.dagger:dagger-compiler:2.19'
 
 	compileOnly 'javax.annotation:jsr250-api:1.0'
 
@@ -67,8 +59,6 @@ task unpackTorBinaries {
 		copy {
 			from configurations.tor.collect { zipTree(it) }
 			into torBinariesDir
-			// TODO: Remove after next Tor upgrade, which won't include non-PIE binaries
-			include 'geoip.zip', '*_pie.zip'
 		}
 	}
 	dependsOn cleanTorBinaries

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

@@ -2,23 +2,10 @@ package org.briarproject.bramble;
 
 import org.briarproject.bramble.battery.AndroidBatteryModule;
 import org.briarproject.bramble.network.AndroidNetworkModule;
-import org.briarproject.bramble.reporting.ReportingModule;
 
 public interface BrambleAndroidEagerSingletons {
 
 	void inject(AndroidBatteryModule.EagerSingletons init);
 
 	void inject(AndroidNetworkModule.EagerSingletons init);
-
-	void inject(ReportingModule.EagerSingletons init);
-
-	class Helper {
-
-		public static void injectEagerSingletons(
-				BrambleAndroidEagerSingletons c) {
-			c.inject(new AndroidBatteryModule.EagerSingletons());
-			c.inject(new AndroidNetworkModule.EagerSingletons());
-			c.inject(new ReportingModule.EagerSingletons());
-		}
-	}
 }

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

@@ -3,8 +3,6 @@ package org.briarproject.bramble;
 import org.briarproject.bramble.battery.AndroidBatteryModule;
 import org.briarproject.bramble.network.AndroidNetworkModule;
 import org.briarproject.bramble.plugin.tor.CircumventionModule;
-import org.briarproject.bramble.reporting.ReportingModule;
-import org.briarproject.bramble.socks.SocksModule;
 import org.briarproject.bramble.system.AndroidSystemModule;
 
 import dagger.Module;
@@ -13,9 +11,12 @@ import dagger.Module;
 		AndroidBatteryModule.class,
 		AndroidNetworkModule.class,
 		AndroidSystemModule.class,
-		CircumventionModule.class,
+		CircumventionModule.class
-		ReportingModule.class,
-		SocksModule.class
 })
 public class BrambleAndroidModule {
+
+	public static void initEagerSingletons(BrambleAndroidEagerSingletons c) {
+		c.inject(new AndroidBatteryModule.EagerSingletons());
+		c.inject(new AndroidNetworkModule.EagerSingletons());
+	}
 }

bramble-android/src/main/java/org/briarproject/bramble/account/AndroidAccountManager.java

@@ -11,24 +11,22 @@ import org.briarproject.bramble.api.db.DatabaseConfig;
 import org.briarproject.bramble.api.identity.IdentityManager;
 
 import java.io.File;
-import java.util.HashSet;
-import java.util.Set;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.GuardedBy;
 import javax.inject.Inject;
 
-import static android.os.Build.VERSION.SDK_INT;
+import static java.util.logging.Logger.getLogger;
-import static java.util.logging.Level.INFO;
 import static org.briarproject.bramble.util.IoUtils.deleteFileOrDir;
-import static org.briarproject.bramble.util.LogUtils.logFileOrDir;
 
 class AndroidAccountManager extends AccountManagerImpl
 		implements AccountManager {
 
 	private static final Logger LOG =
-			Logger.getLogger(AndroidAccountManager.class.getName());
+			getLogger(AndroidAccountManager.class.getName());
+
+	private static final String PREF_DB_KEY = "key";
 
 	protected final Context appContext;
 	private final SharedPreferences prefs;
@@ -42,30 +40,42 @@ class AndroidAccountManager extends AccountManagerImpl
 		appContext = app.getApplicationContext();
 	}
 
+	@GuardedBy("stateChangeLock")
 	@Override
-	public boolean accountExists() {
+	@Nullable
-		boolean exists = super.accountExists();
+	protected String loadEncryptedDatabaseKey() {
-		if (!exists && LOG.isLoggable(INFO)) {
+		String key = getDatabaseKeyFromPreferences();
-			LOG.info("Account does not exist. Contents of account directory:");
+		if (key == null) key = super.loadEncryptedDatabaseKey();
-			logFileOrDir(LOG, INFO, getDataDir());
+		else migrateDatabaseKeyToFile(key);
+		return key;
+	}
+
+	@GuardedBy("stateChangeLock")
+	@Nullable
+	private String getDatabaseKeyFromPreferences() {
+		String key = prefs.getString(PREF_DB_KEY, null);
+		if (key == null) LOG.info("No database key in preferences");
+		else LOG.info("Found database key in preferences");
+		return key;
+	}
+
+	@GuardedBy("stateChangeLock")
+	private void migrateDatabaseKeyToFile(String key) {
+		if (storeEncryptedDatabaseKey(key)) {
+			if (prefs.edit().remove(PREF_DB_KEY).commit())
+				LOG.info("Database key migrated to file");
+			else LOG.warning("Database key not removed from preferences");
+		} else {
+			LOG.warning("Database key not migrated to file");
 		}
-		return exists;
 	}
 
 	@Override
 	public void deleteAccount() {
 		synchronized (stateChangeLock) {
-			if (LOG.isLoggable(INFO)) {
-				LOG.info("Contents of account directory before deleting:");
-				logFileOrDir(LOG, INFO, getDataDir());
-			}
 			super.deleteAccount();
 			SharedPreferences defaultPrefs = getDefaultSharedPreferences();
 			deleteAppData(prefs, defaultPrefs);
-			if (LOG.isLoggable(INFO)) {
-				LOG.info("Contents of account directory after deleting:");
-				logFileOrDir(LOG, INFO, getDataDir());
-			}
 		}
 	}
 
@@ -82,46 +92,20 @@ class AndroidAccountManager extends AccountManagerImpl
 				LOG.warning("Could not clear shared preferences");
 		}
 		// Delete files, except lib and shared_prefs directories
-		Set<File> files = new HashSet<>();
+		File dataDir = new File(appContext.getApplicationInfo().dataDir);
-		File dataDir = getDataDir();
+		File[] children = dataDir.listFiles();
-		@Nullable
+		if (children == null) {
-		File[] fileArray = dataDir.listFiles();
-		if (fileArray == null) {
 			LOG.warning("Could not list files in app data dir");
 		} else {
-			for (File file : fileArray) {
+			for (File child : children) {
-				String name = file.getName();
+				String name = child.getName();
 				if (!name.equals("lib") && !name.equals("shared_prefs")) {
-					files.add(file);
+					deleteFileOrDir(child);
 				}
 			}
 		}
-		files.add(appContext.getFilesDir());
-		files.add(appContext.getCacheDir());
-		addIfNotNull(files, appContext.getExternalCacheDir());
-		if (SDK_INT >= 19) {
-			for (File file : appContext.getExternalCacheDirs()) {
-				addIfNotNull(files, file);
-			}
-		}
-		if (SDK_INT >= 21) {
-			for (File file : appContext.getExternalMediaDirs()) {
-				addIfNotNull(files, file);
-			}
-		}
-		for (File file : files) {
-			deleteFileOrDir(file);
-		}
 		// Recreate the cache dir as some OpenGL drivers expect it to exist
-		if (!new File(dataDir, "cache").mkdirs())
+		if (!new File(dataDir, "cache").mkdir())
 			LOG.warning("Could not recreate cache dir");
 	}
-
-	private File getDataDir() {
-		return new File(appContext.getApplicationInfo().dataDir);
-	}
-
-	private void addIfNotNull(Set<File> files, @Nullable File file) {
-		if (file != null) files.add(file);
-	}
 }

bramble-android/src/main/java/org/briarproject/bramble/network/AndroidNetworkManager.java

@@ -13,8 +13,7 @@ import org.briarproject.bramble.api.lifecycle.Service;
 import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.network.NetworkStatus;
 import org.briarproject.bramble.api.network.event.NetworkStatusEvent;
-import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.system.Scheduler;
 
 import java.util.concurrent.Future;
@@ -34,16 +33,17 @@ 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 java.util.Objects.requireNonNull;
 import static java.util.concurrent.TimeUnit.MINUTES;
 import static java.util.concurrent.TimeUnit.SECONDS;
 import static java.util.logging.Level.INFO;
+import static java.util.logging.Logger.getLogger;
 
-@MethodsNotNullByDefault
+@NotNullByDefault
-@ParametersNotNullByDefault
 class AndroidNetworkManager implements NetworkManager, Service {
 
 	private static final Logger LOG =
-			Logger.getLogger(AndroidNetworkManager.class.getName());
+			getLogger(AndroidNetworkManager.class.getName());
 
 	// See android.net.wifi.WifiManager
 	private static final String WIFI_AP_STATE_CHANGED_ACTION =
@@ -56,6 +56,7 @@ class AndroidNetworkManager implements NetworkManager, Service {
 			new AtomicReference<>();
 	private final AtomicBoolean used = new AtomicBoolean(false);
 
+	@Nullable
 	private volatile BroadcastReceiver networkStateReceiver = null;
 
 	@Inject
@@ -89,9 +90,8 @@ class AndroidNetworkManager implements NetworkManager, Service {
 
 	@Override
 	public NetworkStatus getNetworkStatus() {
-		ConnectivityManager cm = (ConnectivityManager)
+		ConnectivityManager cm = (ConnectivityManager) requireNonNull(
-				appContext.getSystemService(CONNECTIVITY_SERVICE);
+				appContext.getSystemService(CONNECTIVITY_SERVICE));
-		if (cm == null) throw new AssertionError();
 		NetworkInfo net = cm.getActiveNetworkInfo();
 		boolean connected = net != null && net.isConnected();
 		boolean wifi = connected && net.getType() == TYPE_WIFI;

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

@@ -12,8 +12,8 @@ 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.PluginCallback;
 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.api.system.Clock;
@@ -24,7 +24,6 @@ import java.io.IOException;
 import java.security.SecureRandom;
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.List;
 import java.util.UUID;
 import java.util.concurrent.BlockingQueue;
@@ -48,6 +47,7 @@ import static android.bluetooth.BluetoothAdapter.STATE_OFF;
 import static android.bluetooth.BluetoothAdapter.STATE_ON;
 import static android.bluetooth.BluetoothDevice.ACTION_FOUND;
 import static android.bluetooth.BluetoothDevice.EXTRA_DEVICE;
+import static java.util.Collections.shuffle;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
@@ -76,7 +76,7 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 	AndroidBluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
 			Executor ioExecutor, AndroidExecutor androidExecutor,
 			Context appContext, SecureRandom secureRandom, Clock clock,
-			Backoff backoff, PluginCallback callback, int maxLatency) {
+			Backoff backoff, DuplexPluginCallback callback, int maxLatency) {
 		super(connectionLimiter, ioExecutor, secureRandom, backoff, callback,
 				maxLatency);
 		this.androidExecutor = androidExecutor;
@@ -260,7 +260,7 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 			appContext.unregisterReceiver(receiver);
 		}
 		// Shuffle the addresses so we don't always try the same one first
-		Collections.shuffle(addresses);
+		shuffle(addresses);
 		return addresses;
 	}
 

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

@@ -6,9 +6,9 @@ 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.PluginCallback;
 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 org.briarproject.bramble.api.system.Clock;
@@ -61,7 +61,7 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 	}
 
 	@Override
-	public DuplexPlugin createPlugin(PluginCallback callback) {
+	public DuplexPlugin createPlugin(DuplexPluginCallback callback) {
 		BluetoothConnectionLimiter connectionLimiter =
 				new BluetoothConnectionLimiterImpl();
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,

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

@@ -13,7 +13,7 @@ import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.network.event.NetworkStatusEvent;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
-import org.briarproject.bramble.api.plugin.PluginCallback;
+import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
 
 import java.io.IOException;
 import java.net.InetAddress;
@@ -32,6 +32,7 @@ import static android.net.ConnectivityManager.TYPE_WIFI;
 import static android.os.Build.VERSION.SDK_INT;
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
+import static java.util.Objects.requireNonNull;
 import static java.util.logging.Logger.getLogger;
 
 @NotNullByDefault
@@ -61,16 +62,14 @@ class AndroidLanTcpPlugin extends LanTcpPlugin implements EventListener {
 	private volatile SocketFactory socketFactory;
 
 	AndroidLanTcpPlugin(Executor ioExecutor, Context appContext,
-			Backoff backoff, PluginCallback callback, int maxLatency,
+			Backoff backoff, DuplexPluginCallback callback, int maxLatency,
 			int maxIdleTime) {
 		super(ioExecutor, backoff, callback, maxLatency, maxIdleTime);
 		// Don't execute more than one connection status check at a time
 		connectionStatusExecutor =
 				new PoliteExecutor("AndroidLanTcpPlugin", ioExecutor, 1);
-		ConnectivityManager connectivityManager = (ConnectivityManager)
+		connectivityManager = (ConnectivityManager) requireNonNull(
-				appContext.getSystemService(CONNECTIVITY_SERVICE);
+				appContext.getSystemService(CONNECTIVITY_SERVICE));
-		if (connectivityManager == null) throw new AssertionError();
-		this.connectivityManager = connectivityManager;
 		wifiManager = (WifiManager) appContext.getApplicationContext()
 				.getSystemService(WIFI_SERVICE);
 		socketFactory = SocketFactory.getDefault();

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

@@ -6,9 +6,9 @@ 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.PluginCallback;
 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;
@@ -51,7 +51,7 @@ public class AndroidLanTcpPluginFactory implements DuplexPluginFactory {
 	}
 
 	@Override
-	public DuplexPlugin createPlugin(PluginCallback callback) {
+	public DuplexPlugin createPlugin(DuplexPluginCallback callback) {
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		AndroidLanTcpPlugin plugin = new AndroidLanTcpPlugin(ioExecutor,

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

@@ -8,10 +8,9 @@ import android.os.PowerManager;
 
 import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.network.NetworkManager;
-import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
-import org.briarproject.bramble.api.plugin.PluginCallback;
+import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
 import org.briarproject.bramble.api.system.ResourceProvider;
@@ -26,12 +25,15 @@ import javax.net.SocketFactory;
 import static android.content.Context.MODE_PRIVATE;
 import static android.content.Context.POWER_SERVICE;
 import static android.os.PowerManager.PARTIAL_WAKE_LOCK;
+import static java.util.Objects.requireNonNull;
 import static java.util.concurrent.TimeUnit.MINUTES;
 
-@MethodsNotNullByDefault
+@NotNullByDefault
-@ParametersNotNullByDefault
 class AndroidTorPlugin extends TorPlugin {
 
+	// This tag may prevent Huawei's power manager from killing us
+	private static final String WAKE_LOCK_TAG = "LocationManagerService";
+
 	private final Context appContext;
 	private final RenewableWakeLock wakeLock;
 
@@ -41,19 +43,17 @@ class AndroidTorPlugin extends TorPlugin {
 			Clock clock, ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
 			BatteryManager batteryManager, Backoff backoff,
-			TorRendezvousCrypto torRendezvousCrypto,
+			DuplexPluginCallback callback, String architecture, int maxLatency,
-			PluginCallback callback, String architecture, int maxLatency,
 			int maxIdleTime) {
 		super(ioExecutor, networkManager, locationUtils, torSocketFactory,
 				clock, resourceProvider, circumventionProvider, batteryManager,
-				backoff, torRendezvousCrypto, callback, architecture, maxLatency, maxIdleTime,
+				backoff, callback, architecture, maxLatency, maxIdleTime,
 				appContext.getDir("tor", MODE_PRIVATE));
 		this.appContext = appContext;
 		PowerManager pm = (PowerManager)
-				appContext.getSystemService(POWER_SERVICE);
+				requireNonNull(appContext.getSystemService(POWER_SERVICE));
-		if (pm == null) throw new AssertionError();
 		wakeLock = new RenewableWakeLock(pm, scheduler, PARTIAL_WAKE_LOCK,
-				getWakeLockTag(), 1, MINUTES);
+				WAKE_LOCK_TAG, 1, MINUTES);
 	}
 
 	@Override
@@ -85,17 +85,4 @@ class AndroidTorPlugin extends TorPlugin {
 		super.stop();
 		wakeLock.release();
 	}
-
-	private String getWakeLockTag() {
-		PackageManager pm = appContext.getPackageManager();
-		for (PackageInfo info : pm.getInstalledPackages(0)) {
-			String name = info.packageName.toLowerCase();
-			if (name.startsWith("com.huawei.powergenie")) {
-				return "LocationManagerService";
-			} else if (name.startsWith("com.evenwell.powermonitor")) {
-				return "AudioIn";
-			}
-		}
-		return getClass().getSimpleName();
-	}
 }

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

@@ -8,10 +8,10 @@ import org.briarproject.bramble.api.network.NetworkManager;
 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.PluginCallback;
 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.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
@@ -25,12 +25,15 @@ import java.util.logging.Logger;
 import javax.annotation.concurrent.Immutable;
 import javax.net.SocketFactory;
 
+import static android.os.Build.VERSION.SDK_INT;
+import static java.util.logging.Logger.getLogger;
+
 @Immutable
 @NotNullByDefault
 public class AndroidTorPluginFactory implements DuplexPluginFactory {
 
 	private static final Logger LOG =
-			Logger.getLogger(AndroidTorPluginFactory.class.getName());
+			getLogger(AndroidTorPluginFactory.class.getName());
 
 	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
 	private static final int MAX_IDLE_TIME = 30 * 1000; // 30 seconds
@@ -83,20 +86,14 @@ public class AndroidTorPluginFactory implements DuplexPluginFactory {
 	}
 
 	@Override
-	public DuplexPlugin createPlugin(PluginCallback callback) {
+	public DuplexPlugin createPlugin(DuplexPluginCallback callback) {
 
 		// Check that we have a Tor binary for this architecture
 		String architecture = null;
 		for (String abi : AndroidUtils.getSupportedArchitectures()) {
-			if (abi.startsWith("x86_64")) {
+			if (abi.startsWith("x86")) {
-				architecture = "x86_64";
-				break;
-			} else if (abi.startsWith("x86")) {
 				architecture = "x86";
 				break;
-			} else if (abi.startsWith("arm64")) {
-				architecture = "arm64";
-				break;
 			} else if (abi.startsWith("armeabi")) {
 				architecture = "arm";
 				break;
@@ -106,17 +103,15 @@ public class AndroidTorPluginFactory implements DuplexPluginFactory {
 			LOG.info("Tor is not supported on this architecture");
 			return null;
 		}
-		// Use position-independent executable
+		// Use position-independent executable for SDK >= 16
-		architecture += "_pie";
+		if (SDK_INT >= 16) architecture += "_pie";
 
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		TorRendezvousCrypto torRendezvousCrypto = new TorRendezvousCryptoImpl();
 		AndroidTorPlugin plugin = new AndroidTorPlugin(ioExecutor, scheduler,
 				appContext, networkManager, locationUtils, torSocketFactory,
 				clock, resourceProvider, circumventionProvider, batteryManager,
-				backoff, torRendezvousCrypto, callback, architecture,
+				backoff, callback, architecture, MAX_LATENCY, MAX_IDLE_TIME);
-				MAX_LATENCY, MAX_IDLE_TIME);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

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

@@ -15,12 +15,13 @@ import java.util.logging.Logger;
 import javax.inject.Inject;
 
 import static android.content.Context.TELEPHONY_SERVICE;
+import static java.util.logging.Logger.getLogger;
 
 @NotNullByDefault
 class AndroidLocationUtils implements LocationUtils {
 
 	private static final Logger LOG =
-			Logger.getLogger(AndroidLocationUtils.class.getName());
+			getLogger(AndroidLocationUtils.class.getName());
 
 	private final Context appContext;
 
@@ -59,14 +60,14 @@ class AndroidLocationUtils implements LocationUtils {
 	}
 
 	private String getCountryFromPhoneNetwork() {
-		Object o = appContext.getSystemService(TELEPHONY_SERVICE);
+		TelephonyManager tm = (TelephonyManager)
-		TelephonyManager tm = (TelephonyManager) o;
+				appContext.getSystemService(TELEPHONY_SERVICE);
-		return tm.getNetworkCountryIso();
+		return tm == null ? "" : tm.getNetworkCountryIso();
 	}
 
 	private String getCountryFromSimCard() {
-		Object o = appContext.getSystemService(TELEPHONY_SERVICE);
+		TelephonyManager tm = (TelephonyManager)
-		TelephonyManager tm = (TelephonyManager) o;
+				appContext.getSystemService(TELEPHONY_SERVICE);
-		return tm.getSimCountryIso();
+		return tm == null ? "" : tm.getSimCountryIso();
 	}
 }

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

@@ -8,7 +8,6 @@ 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.os.StrictMode;
 import android.provider.Settings;
@@ -23,6 +22,8 @@ import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
 import static android.content.Context.WIFI_SERVICE;
+import static android.os.Build.FINGERPRINT;
+import static android.os.Build.SERIAL;
 import static android.os.Build.VERSION.SDK_INT;
 import static android.provider.Settings.Secure.ANDROID_ID;
 
@@ -46,8 +47,8 @@ class AndroidSecureRandomProvider extends UnixSecureRandomProvider {
 		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 (FINGERPRINT != null) out.writeUTF(FINGERPRINT);
-		if (Build.SERIAL != null) out.writeUTF(Build.SERIAL);
+		if (SERIAL != null) out.writeUTF(SERIAL);
 		ContentResolver contentResolver = appContext.getContentResolver();
 		String id = Settings.Secure.getString(contentResolver, ANDROID_ID);
 		if (id != null) out.writeUTF(id);
@@ -75,14 +76,13 @@ class AndroidSecureRandomProvider extends UnixSecureRandomProvider {
 		// Silence strict mode
 		StrictMode.ThreadPolicy tp = StrictMode.allowThreadDiskWrites();
 		super.writeSeed();
-		if (SDK_INT <= 18) applyOpenSslFix();
+		if (SDK_INT >= 16 && SDK_INT <= 18) applyOpenSslFix();
 		StrictMode.setThreadPolicy(tp);
 	}
 
 	// Based on https://android-developers.googleblog.com/2013/08/some-securerandom-thoughts.html
 	private void applyOpenSslFix() {
-		byte[] seed = new UnixSecureRandomSpi().engineGenerateSeed(
+		byte[] seed = new UnixSecureRandomSpi().engineGenerateSeed(SEED_LENGTH);
-				SEED_LENGTH);
 		try {
 			// Seed the OpenSSL PRNG
 			Class.forName("org.apache.harmony.xnet.provider.jsse.NativeCrypto")

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

@@ -1,13 +1,10 @@
 package org.briarproject.bramble.system;
 
-import org.briarproject.bramble.api.event.EventExecutor;
 import org.briarproject.bramble.api.system.AndroidExecutor;
 import org.briarproject.bramble.api.system.LocationUtils;
 import org.briarproject.bramble.api.system.ResourceProvider;
 import org.briarproject.bramble.api.system.SecureRandomProvider;
 
-import java.util.concurrent.Executor;
-
 import javax.inject.Singleton;
 
 import dagger.Module;
@@ -35,13 +32,6 @@ public class AndroidSystemModule {
 		return androidExecutor;
 	}
 
-	@Provides
-	@Singleton
-	@EventExecutor
-	Executor provideEventExecutor(AndroidExecutor androidExecutor) {
-		return androidExecutor::runOnUiThread;
-	}
-
 	@Provides
 	@Singleton
 	ResourceProvider provideResourceProvider(AndroidResourceProvider provider) {

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

@@ -3,28 +3,21 @@ package org.briarproject.bramble.util;
 import android.annotation.SuppressLint;
 import android.bluetooth.BluetoothAdapter;
 import android.content.Context;
-import android.os.Build;
 import android.provider.Settings;
 
-import org.briarproject.bramble.api.Pair;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
 import java.io.File;
-import java.lang.reflect.Field;
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
 
-import javax.annotation.Nullable;
-
 import static android.content.Context.MODE_PRIVATE;
+import static android.os.Build.CPU_ABI;
+import static android.os.Build.CPU_ABI2;
+import static android.os.Build.SUPPORTED_ABIS;
 import static android.os.Build.VERSION.SDK_INT;
 import static java.util.Arrays.asList;
-import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
+import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 
-@NotNullByDefault
 public class AndroidUtils {
 
 	// Fake Bluetooth address returned by BluetoothAdapter on API 23 and later
@@ -35,86 +28,35 @@ public class AndroidUtils {
 	public static Collection<String> getSupportedArchitectures() {
 		List<String> abis = new ArrayList<>();
 		if (SDK_INT >= 21) {
-			abis.addAll(asList(Build.SUPPORTED_ABIS));
+			abis.addAll(asList(SUPPORTED_ABIS));
 		} else {
-			abis.add(Build.CPU_ABI);
+			abis.add(CPU_ABI);
-			if (Build.CPU_ABI2 != null) abis.add(Build.CPU_ABI2);
+			if (CPU_ABI2 != null) abis.add(CPU_ABI2);
 		}
 		return abis;
 	}
 
 	public static String getBluetoothAddress(Context ctx,
 			BluetoothAdapter adapter) {
-		return getBluetoothAddressAndMethod(ctx, adapter).getFirst();
-	}
-
-	public static Pair<String, String> getBluetoothAddressAndMethod(Context ctx,
-			BluetoothAdapter adapter) {
 		// Return the adapter's address if it's valid and not fake
 		@SuppressLint("HardwareIds")
 		String address = adapter.getAddress();
-		if (isValidBluetoothAddress(address)) {
+		if (isValidBluetoothAddress(address)) return address;
-			return new Pair<>(address, "adapter");
-		}
 		// Return the address from settings if it's valid and not fake
 		address = Settings.Secure.getString(ctx.getContentResolver(),
 				"bluetooth_address");
-		if (isValidBluetoothAddress(address)) {
+		if (isValidBluetoothAddress(address)) return address;
-			return new Pair<>(address, "settings");
-		}
-		// Try to get the address via reflection
-		address = getBluetoothAddressByReflection(adapter);
-		if (isValidBluetoothAddress(address)) {
-			return new Pair<>(requireNonNull(address), "reflection");
-		}
 		// Let the caller know we can't find the address
-		return new Pair<>("", "");
+		return "";
 	}
 
-	private static boolean isValidBluetoothAddress(@Nullable String address) {
+	private static boolean isValidBluetoothAddress(String address) {
-		return !StringUtils.isNullOrEmpty(address)
+		return !isNullOrEmpty(address)
 				&& BluetoothAdapter.checkBluetoothAddress(address)
 				&& !address.equals(FAKE_BLUETOOTH_ADDRESS);
 	}
 
-	@Nullable
-	private static String getBluetoothAddressByReflection(
-			BluetoothAdapter adapter) {
-		try {
-			Field mServiceField =
-					adapter.getClass().getDeclaredField("mService");
-			mServiceField.setAccessible(true);
-			Object mService = mServiceField.get(adapter);
-			// mService may be null when Bluetooth is disabled
-			if (mService == null) throw new NoSuchFieldException();
-			Method getAddressMethod =
-					mService.getClass().getMethod("getAddress");
-			return (String) getAddressMethod.invoke(mService);
-		} catch (NoSuchFieldException e) {
-			return null;
-		} catch (IllegalAccessException e) {
-			return null;
-		} catch (NoSuchMethodException e) {
-			return null;
-		} catch (InvocationTargetException e) {
-			return null;
-		} catch (SecurityException e) {
-			return null;
-		}
-	}
-
 	public static File getReportDir(Context ctx) {
 		return ctx.getDir(STORED_REPORTS, MODE_PRIVATE);
 	}
-
-	/**
-	 * Returns an array of supported content types for image attachments.
-	 * GIFs can't be compressed on API < 24 so they're not supported.
-	 * <p>
-	 * TODO: Remove this restriction when large message support is added
-	 */
-	public static String[] getSupportedImageContentTypes() {
-		if (SDK_INT < 24) return new String[] {"image/jpeg", "image/png"};
-		else return new String[] {"image/jpeg", "image/png", "image/gif"};
-	}
 }

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

@@ -10,17 +10,19 @@ import java.util.concurrent.TimeUnit;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
+import javax.annotation.concurrent.GuardedBy;
 import javax.annotation.concurrent.ThreadSafe;
 
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.logging.Level.INFO;
+import static java.util.logging.Logger.getLogger;
 
 @ThreadSafe
 @NotNullByDefault
 public class RenewableWakeLock {
 
 	private static final Logger LOG =
-			Logger.getLogger(RenewableWakeLock.class.getName());
+			getLogger(RenewableWakeLock.class.getName());
 
 	/**
 	 * Automatically release the lock this many milliseconds after it's due
@@ -36,10 +38,12 @@ public class RenewableWakeLock {
 	private final Runnable renewTask;
 
 	private final Object lock = new Object();
+	@GuardedBy("lock")
 	@Nullable
-	private PowerManager.WakeLock wakeLock; // Locking: lock
+	private PowerManager.WakeLock wakeLock;
+	@GuardedBy("lock")
 	@Nullable
-	private ScheduledFuture future; // Locking: lock
+	private ScheduledFuture future;
 
 	public RenewableWakeLock(PowerManager powerManager,
 			ScheduledExecutorService scheduler, int levelAndFlags, String tag,

bramble-android/src/test/java/org/briarproject/bramble/account/AndroidAccountManagerTest.java

@@ -16,10 +16,13 @@ import org.junit.Test;
 
 import java.io.File;
 
+import static junit.framework.Assert.assertEquals;
 import static junit.framework.Assert.assertFalse;
 import static junit.framework.Assert.assertTrue;
 import static org.briarproject.bramble.test.TestUtils.deleteTestDirectory;
+import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
 import static org.briarproject.bramble.test.TestUtils.getTestDirectory;
+import static org.briarproject.bramble.util.StringUtils.toHexString;
 
 public class AndroidAccountManagerTest extends BrambleMockTestCase {
 
@@ -37,8 +40,11 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 	private final Application app;
 	private final ApplicationInfo applicationInfo;
 
+	private final String encryptedKeyHex = toHexString(getRandomBytes(123));
 	private final File testDir = getTestDirectory();
 	private final File keyDir = new File(testDir, "key");
+	private final File keyFile = new File(keyDir, "db.key");
+	private final File keyBackupFile = new File(keyDir, "db.key.bak");
 	private final File dbDir = new File(testDir, "db");
 
 	private AndroidAccountManager accountManager;
@@ -69,6 +75,29 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 		};
 	}
 
+	@Test
+	public void testDbKeyIsMigratedFromPreferencesToFile() {
+		context.checking(new Expectations() {{
+			oneOf(prefs).getString("key", null);
+			will(returnValue(encryptedKeyHex));
+			oneOf(prefs).edit();
+			will(returnValue(editor));
+			oneOf(editor).remove("key");
+			will(returnValue(editor));
+			oneOf(editor).commit();
+			will(returnValue(true));
+		}});
+
+		assertFalse(keyFile.exists());
+		assertFalse(keyBackupFile.exists());
+
+		assertEquals(encryptedKeyHex,
+				accountManager.loadEncryptedDatabaseKey());
+
+		assertTrue(keyFile.exists());
+		assertTrue(keyBackupFile.exists());
+	}
+
 	@Test
 	public void testDeleteAccountClearsSharedPrefsAndDeletesFiles()
 			throws Exception {
@@ -83,8 +112,6 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 		// Other directories should be deleted
 		File potatoDir = new File(testDir, ".potato");
 		File potatoFile = new File(potatoDir, "file");
-		File filesDir = new File(testDir, "filesDir");
-		File externalCacheDir = new File(testDir, "externalCacheDir");
 
 		context.checking(new Expectations() {{
 			oneOf(prefs).edit();
@@ -99,14 +126,8 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 			will(returnValue(editor));
 			oneOf(editor).commit();
 			will(returnValue(true));
-			allowing(app).getApplicationInfo();
+			oneOf(app).getApplicationInfo();
 			will(returnValue(applicationInfo));
-			oneOf(app).getFilesDir();
-			will(returnValue(filesDir));
-			oneOf(app).getCacheDir();
-			will(returnValue(cacheDir));
-			oneOf(app).getExternalCacheDir();
-			will(returnValue(externalCacheDir));
 		}});
 
 		assertTrue(dbDir.mkdirs());
@@ -119,8 +140,6 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 		assertTrue(cacheFile.createNewFile());
 		assertTrue(potatoDir.mkdirs());
 		assertTrue(potatoFile.createNewFile());
-		assertTrue(filesDir.mkdirs());
-		assertTrue(externalCacheDir.mkdirs());
 
 		accountManager.deleteAccount();
 
@@ -134,8 +153,6 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 		assertFalse(cacheFile.exists());
 		assertFalse(potatoDir.exists());
 		assertFalse(potatoFile.exists());
-		assertFalse(filesDir.exists());
-		assertFalse(externalCacheDir.exists());
 	}
 
 	@After

bramble-android/witness.gradle

@@ -1,47 +1,47 @@
 dependencyVerification {
     verify = [
         'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
-        'com.android.tools.analytics-library:protos:26.5.1:protos-26.5.1.jar:8dde1130725461fe827f2a343d353f2b51e8870661fc860d7d5ebddb097ead4e',
+        'com.android.tools.analytics-library:protos:26.2.1:protos-26.2.1.jar:2f371f5b1f551e85ab08be4d6a2873471b3d44afd1ebf6aa3298f3b796bf691f',
-        'com.android.tools.analytics-library:shared:26.5.1:shared-26.5.1.jar:ccc2f3b00ec17b11401610ba68553544fc8fc517120e84439ac6eb86b875e18d',
+        'com.android.tools.analytics-library:shared:26.2.1:shared-26.2.1.jar:4c1e4e705fa4d45f23aaea230557f6508155012d9c296337787c1d7b26a97f5a',
-        'com.android.tools.analytics-library:tracker:26.5.1:tracker-26.5.1.jar:3a76984c0fe2e847ca7a8b35b4780ef0447a9d1666946cb8e60466318e0ab5ae',
+        'com.android.tools.analytics-library:tracker:26.2.1:tracker-26.2.1.jar:4a624ecc976539f755ddb0bb8dfc2dd3d08326cfec59a098dbd70f701ca7fb75',
-        'com.android.tools.build:aapt2-proto:0.4.0:aapt2-proto-0.4.0.jar:fac0435e08898f89eeeb9ca236bea707155ff816c12205ced285ad53604133ca',
+        'com.android.tools.build:aapt2:3.2.1-4818971:aapt2-3.2.1-4818971-linux.jar:f431b6f96c91a2c155144b091a9c97d9805c589fe8efc9c930b6cd346cb60a1e',
-        'com.android.tools.build:apksig:3.5.1:apksig-3.5.1.jar:1fd33e7f009a2a0da766cfeec4211a09f548034b015c289a66d75dd8a9302f4a',
+        'com.android.tools.build:apksig:3.2.1:apksig-3.2.1.jar:2b46f2feffea66037aab29e4261b2433c190194a6ef97b958511eb157f2ccba5',
-        'com.android.tools.build:apkzlib:3.5.1:apkzlib-3.5.1.jar:9f330167cbe973b7db407692f74f4f6453b7ffa5f2048934b06280c2ceee60fa',
+        'com.android.tools.build:apkzlib:3.2.1:apkzlib-3.2.1.jar:c39ad0313905932431fe81c8899c2cf39a4d92ad6c4edcaa4b25432f461452aa',
-        'com.android.tools.build:builder-model:3.5.1:builder-model-3.5.1.jar:39ea3c82b76b6e0c9f9fa88d93e0edc1dd4a0f1dfae0ef6fbf2d451da47e5450',
+        'com.android.tools.build:builder-model:3.2.1:builder-model-3.2.1.jar:a9f68e6abcec122f9cb5ad352d3f05a3eb03acbcdca95e4d25c16310c2c965ff',
-        'com.android.tools.build:builder-test-api:3.5.1:builder-test-api-3.5.1.jar:a1b59305584cbcaa078fdc9cfb80871012755b822dd32e8da19add6f7bbcb762',
+        'com.android.tools.build:builder-test-api:3.2.1:builder-test-api-3.2.1.jar:533ac6c2b5884bb54967a33791f2628dfdfac7981af39417a333b43d4379b6be',
-        'com.android.tools.build:builder:3.5.1:builder-3.5.1.jar:e3a8d382434c5f60990730c4719fc814e85a898a33a1e96c1df8d627d3c6eea6',
+        'com.android.tools.build:builder:3.2.1:builder-3.2.1.jar:aedcbfd115dbe91d09b4113e66ef50589b558d0aa3b2f133b1d867c9b87fae83',
-        'com.android.tools.build:gradle-api:3.5.1:gradle-api-3.5.1.jar:be9b41859bace11998f66b04ed944f87e413f3ad6da3c4665587699da125addc',
+        'com.android.tools.build:gradle-api:3.2.1:gradle-api-3.2.1.jar:57cf0ac5ac1dca8afdb3f62b94265e776e7dcfa641cc3844fb53a05193de208d',
-        'com.android.tools.build:manifest-merger:26.5.1:manifest-merger-26.5.1.jar:dcad9ecb967251f4d750f55a4204a2b400e8fbfe5cb930a1d0d5dbe10ae8bdfc',
+        'com.android.tools.build:manifest-merger:26.2.1:manifest-merger-26.2.1.jar:8830573263361035d38cfdcb51e2db94029c93865b21334f5fbf8a27984281a6',
-        'com.android.tools.ddms:ddmlib:26.5.1:ddmlib-26.5.1.jar:b081aef2a4ed3f4d47cae4cdb128469735f25a114e026d37123bf9ffdec742a8',
+        'com.android.tools.ddms:ddmlib:26.2.1:ddmlib-26.2.1.jar:a4bf0a29a19980bf27269465cc782064656750b77c26728f82f9e148b705218b',
-        'com.android.tools.external.com-intellij:intellij-core:26.5.1:intellij-core-26.5.1.jar:20eced30adc124805bd93488d9cd9d3e33e6bf7b48e9fe5a703d4983f894d450',
+        'com.android.tools.external.com-intellij:intellij-core:26.2.1:intellij-core-26.2.1.jar:4925ad1892c2687cb1a63427d440ef519c8c59215fefe0dc5d541d5d411fcafe',
-        'com.android.tools.external.com-intellij:kotlin-compiler:26.5.1:kotlin-compiler-26.5.1.jar:5aed762dd54875b77ae7018d97c05756ff0c5b9fd02ec595dd396ccd14cc22cb',
+        'com.android.tools.external.com-intellij:kotlin-compiler:26.2.1:kotlin-compiler-26.2.1.jar:daa064fd708f340ee25fb9823c4c74104ac77f1370b76d907eb9ae6daec0a2ae',
-        'com.android.tools.external.org-jetbrains:uast:26.5.1:uast-26.5.1.jar:4bc8653d6c0943f40fee963a149e36c6baa45683d2530968a13f5007e3c40740',
+        'com.android.tools.external.org-jetbrains:uast:26.2.1:uast-26.2.1.jar:f10f7258d2ab9189562cc0f9ad838c0378fdba439229173390a99de02ebac75b',
-        'com.android.tools.layoutlib:layoutlib-api:26.5.1:layoutlib-api-26.5.1.jar:88732f11396c427273e515d23042e35633f4fe4295528a99b866aa2adf0efd9c',
+        'com.android.tools.layoutlib:layoutlib-api:26.2.1:layoutlib-api-26.2.1.jar:ddbf4fca123733fa011595b1cc1f4ac2937ed327b60990711fafc33c775c2ade',
-        'com.android.tools.lint:lint-api:26.5.1:lint-api-26.5.1.jar:ec33fcd72bfaf70dd841e03fbfd93f109c2e575aec146067c606689c3972f0de',
+        'com.android.tools.lint:lint-api:26.2.1:lint-api-26.2.1.jar:3b57e739de567b98bc9ab56c2c0ee66fc026b4adf5843e8f9804ca0666a6f66e',
-        'com.android.tools.lint:lint-checks:26.5.1:lint-checks-26.5.1.jar:a1b9607d484aaae7a71dcecdc76f8003d8239af226c776894a2cf63f9e6c60d7',
+        'com.android.tools.lint:lint-checks:26.2.1:lint-checks-26.2.1.jar:c86f4cc9aaee722ee4ad70062f7b5af91e9b041914af27adc09f545ab0fb3bc6',
-        'com.android.tools.lint:lint-gradle-api:26.5.1:lint-gradle-api-26.5.1.jar:82453fd98a8394cc84ed995c04d2cd744abd1d6589403427ba7eef53115406f3',
+        'com.android.tools.lint:lint-gradle-api:26.2.1:lint-gradle-api-26.2.1.jar:2283e7af32e301565f2a797e531f0fc8c648077d457afb3ffdddbee638976c2f',
-        'com.android.tools.lint:lint-gradle:26.5.1:lint-gradle-26.5.1.jar:59465b56cf7db77c656d5f8195d721c3d48b6bdd0502d774de335bfe4baff00b',
+        'com.android.tools.lint:lint-gradle:26.2.1:lint-gradle-26.2.1.jar:8fd90b2f3ec788cbb9801c07ab3e1ea2255aa31a6093157d7ea0ff13d0315ecb',
-        'com.android.tools.lint:lint:26.5.1:lint-26.5.1.jar:336e4b04ec6f8b0f25879131b7a7862d77df83a1879ee5b71be26128755f8e2e',
+        'com.android.tools.lint:lint-kotlin:26.2.1:lint-kotlin-26.2.1.jar:7a6a5d2b18f69cf1b900d857c2632b4c683713c533295933b8b759f8cab4a877',
-        'com.android.tools:annotations:26.5.1:annotations-26.5.1.jar:2c43c82f8c59d8f7a61e3239e1a2dc9f69dc342ec09af9b7c9f69b25337c0b6e',
+        'com.android.tools.lint:lint:26.2.1:lint-26.2.1.jar:7848b82ae988b90dee259ae7c7e86e05cbf52db6cd21c8bbd38ce7df08f3f8c5',
-        'com.android.tools:common:26.5.1:common-26.5.1.jar:eccfa54486ed54c4e3123cc42195d023bd0dd21bcd2f0e4868e8c6fc70f8ef6b',
+        'com.android.tools:annotations:26.2.1:annotations-26.2.1.jar:7391c6a1e080174b96e64ceb078dadd31ce4d8a2d2fee0ec65be202126f90f24',
-        'com.android.tools:dvlib:26.5.1:dvlib-26.5.1.jar:46f93ad498b4756e7d867d2fe38c38890a80e7407a4ae459e4a8c8d5c5aeacfe',
+        'com.android.tools:common:26.2.1:common-26.2.1.jar:a50aab2d6411ff68f4004a87c7e93d87d8e980a0ec3b352246549897ea2d78e5',
-        'com.android.tools:repository:26.5.1:repository-26.5.1.jar:2b3ee791aa4c3e8ce60498c161a27ca7228816fc630eed4d9f25f2f36a106dce',
+        'com.android.tools:dvlib:26.2.1:dvlib-26.2.1.jar:72a83bf2839b1df9b1fbf67ba45d1bfb9f966cd774da4320c762b2be8f1688aa',
-        'com.android.tools:sdk-common:26.5.1:sdk-common-26.5.1.jar:365f749676c3574676fd465177c8a492f340816db2b520d6ed114d3b6e77bea7',
+        'com.android.tools:repository:26.2.1:repository-26.2.1.jar:fa74dae09103faef703df38550ad8fa244c5b6d1bf90d6198be932292b3d9cc1',
-        'com.android.tools:sdklib:26.5.1:sdklib-26.5.1.jar:007da104afb27c8c682a1628023fe9ec438249c8d15ef0fd6624c5bb8e23b696',
+        'com.android.tools:sdk-common:26.2.1:sdk-common-26.2.1.jar:759d4b292ca69a35cf961fca377b54158fc6c88108978006999442e80a011cf4',
-        'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
+        'com.android.tools:sdklib:26.2.1:sdklib-26.2.1.jar:248df7ad5eac4aeb6f96c394c76760de4b7b89ac056e54d0c21a739368b91b45',
-        'com.google.code.gson:gson:2.8.5:gson-2.8.5.jar:233a0149fc365c9f6edbd683cfe266b19bdc773be98eabdaf6b3c924b48e7d81',
+        'com.google.code.findbugs:jsr305:1.3.9:jsr305-1.3.9.jar:905721a0eea90a81534abb7ee6ef4ea2e5e645fa1def0a5cd88402df1b46c9ed',
-        'com.google.dagger:dagger-compiler:2.24:dagger-compiler-2.24.jar:3c5afb955fb188da485cb2c048eff37dce0e1530b9780a0f2f7187d16d1ccc1f',
+        'com.google.code.gson:gson:2.8.0:gson-2.8.0.jar:c6221763bd79c4f1c3dc7f750b5f29a0bb38b367b81314c4f71896e340c40825',
-        'com.google.dagger:dagger-producers:2.24:dagger-producers-2.24.jar:f10f45b95191954d5d6b043fca9e62fb621d21bf70634b8f8476c7988b504c3a',
+        'com.google.dagger:dagger-compiler:2.19:dagger-compiler-2.19.jar:27a4b202a2de908182edb261f8c0a264e08e5e4733d7514bc7fbf0d31da5c0fc',
-        'com.google.dagger:dagger-spi:2.24:dagger-spi-2.24.jar:c038445d14dbcb4054e61bf49e05009edf26fce4fdc7ec1a9db544784f68e718',
+        'com.google.dagger:dagger-producers:2.19:dagger-producers-2.19.jar:a17663abe0fc38b676026950907d4c5f5e2bf338375415861eaff6e3bdb0b768',
-        'com.google.dagger:dagger:2.24:dagger-2.24.jar:550a6e46a6dfcdf1d764887b6090cea94f783327e50e5c73754f18facfc70b64',
+        'com.google.dagger:dagger-spi:2.19:dagger-spi-2.19.jar:e7a6379d82c841f6aac2866948ad1eed716528707814602842a8d844ce04e2e1',
-        'com.google.errorprone:error_prone_annotations:2.2.0:error_prone_annotations-2.2.0.jar:6ebd22ca1b9d8ec06d41de8d64e0596981d9607b42035f9ed374f9de271a481a',
+        'com.google.dagger:dagger:2.19:dagger-2.19.jar:514b6f1e0727c6572e1d65cb27e4ae668b7aeaeb93a29515182965265b609939',
+        'com.google.errorprone:error_prone_annotations:2.0.18:error_prone_annotations-2.0.18.jar:cb4cfad870bf563a07199f3ebea5763f0dec440fcda0b318640b1feaa788656b',
+        'com.google.errorprone:error_prone_annotations:2.1.3:error_prone_annotations-2.1.3.jar:03d0329547c13da9e17c634d1049ea2ead093925e290567e1a364fd6b1fc7ff8',
         'com.google.errorprone:javac-shaded:9-dev-r4023-3:javac-shaded-9-dev-r4023-3.jar:65bfccf60986c47fbc17c9ebab0be626afc41741e0a6ec7109e0768817a36f30',
         'com.google.googlejavaformat:google-java-format:1.5:google-java-format-1.5.jar:aa19ad7850fb85178aa22f2fddb163b84d6ce4d0035872f30d4408195ca1144e',
-        'com.google.guava:failureaccess:1.0.1:failureaccess-1.0.1.jar:a171ee4c734dd2da837e4b16be9df4661afab72a41adaf31eb84dfdaf936ca26',
+        'com.google.guava:guava:23.0:guava-23.0.jar:7baa80df284117e5b945b19b98d367a85ea7b7801bd358ff657946c3bd1b6596',
-        'com.google.guava:guava:27.0.1-jre:guava-27.0.1-jre.jar:e1c814fd04492a27c38e0317eabeaa1b3e950ec8010239e400fe90ad6c9107b4',
+        'com.google.guava:guava:25.0-jre:guava-25.0-jre.jar:3fd4341776428c7e0e5c18a7c10de129475b69ab9d30aeafbb5c277bb6074fa9',
-        'com.google.guava:guava:27.1-jre:guava-27.1-jre.jar:4a5aa70cc968a4d137e599ad37553e5cfeed2265e8c193476d7119036c536fe7',
+        'com.google.j2objc:j2objc-annotations:1.1:j2objc-annotations-1.1.jar:40ceb7157feb263949e0f503fe5f71689333a621021aa20ce0d0acee3badaa0f',
-        'com.google.guava:listenablefuture:9999.0-empty-to-avoid-conflict-with-guava:listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar:b372a037d4230aa57fbeffdef30fd6123f9c0c2db85d0aced00c91b974f33f99',
-        'com.google.j2objc:j2objc-annotations:1.1:j2objc-annotations-1.1.jar:2994a7eb78f2710bd3d3bfb639b2c94e219cedac0d4d084d516e78c16dddecf6',
         'com.google.jimfs:jimfs:1.1:jimfs-1.1.jar:c4828e28d7c0a930af9387510b3bada7daa5c04d7c25a75c7b8b081f1c257ddd',
         'com.google.protobuf:protobuf-java:3.4.0:protobuf-java-3.4.0.jar:dce7e66b32456a1b1198da0caff3a8acb71548658391e798c79369241e6490a4',
         'com.googlecode.json-simple:json-simple:1.1:json-simple-1.1.jar:2d9484f4c649f708f47f9a479465fc729770ee65617dca3011836602264f6439',
@@ -50,41 +50,39 @@ dependencyVerification {
         'com.sun.activation:javax.activation:1.2.0:javax.activation-1.2.0.jar:993302b16cd7056f21e779cc577d175a810bb4900ef73cd8fbf2b50f928ba9ce',
         'com.sun.istack:istack-commons-runtime:2.21:istack-commons-runtime-2.21.jar:c33e67a0807095f02a0e2da139412dd7c4f9cc1a4c054b3e434f96831ba950f4',
         'com.sun.xml.fastinfoset:FastInfoset:1.2.13:FastInfoset-1.2.13.jar:27a77db909f3c2833c0b1a37c55af1db06045118ad2eed96ce567b6632bce038',
-        'commons-codec:commons-codec:1.10:commons-codec-1.10.jar:4241dfa94e711d435f29a4604a3e2de5c4aa3c165e23bd066be6fc1fc4309569',
+        'commons-codec:commons-codec:1.9:commons-codec-1.9.jar:ad19d2601c3abf0b946b5c3a4113e226a8c1e3305e395b90013b78dd94a723ce',
         'commons-logging:commons-logging:1.2:commons-logging-1.2.jar:daddea1ea0be0f56978ab3006b8ac92834afeefbd9b7e4e6316fca57df0fa636',
         'it.unimi.dsi:fastutil:7.2.0:fastutil-7.2.0.jar:74fa208043740642f7e6eb09faba15965218ad2f50ce3020efb100136e4b591c',
         'javax.annotation:jsr250-api:1.0:jsr250-api-1.0.jar:a1a922d0d9b6d183ed3800dfac01d1e1eb159f0e8c6f94736931c1def54a941f',
         'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
         'javax.xml.bind:jaxb-api:2.2.12-b140109.1041:jaxb-api-2.2.12-b140109.1041.jar:b5e60cd8b7b5ff01ce4a74c5dd008f4fbd14ced3495d0b47b85cfedc182211f2',
         'junit:junit:4.12:junit-4.12.jar:59721f0805e223d84b90677887d9ff567dc534d7c502ca903c0c2b17f05c116a',
-        'net.ltgt.gradle.incap:incap:0.2:incap-0.2.jar:b625b9806b0f1e4bc7a2e3457119488de3cd57ea20feedd513db070a573a4ffd',
         'net.sf.jopt-simple:jopt-simple:4.9:jopt-simple-4.9.jar:26c5856e954b5f864db76f13b86919b59c6eecf9fd930b96baa8884626baf2f5',
         'net.sf.kxml:kxml2:2.3.0:kxml2-2.3.0.jar:f264dd9f79a1fde10ce5ecc53221eff24be4c9331c830b7d52f2f08a7b633de2',
         '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.apache.commons:commons-compress:1.12:commons-compress-1.12.jar:2c1542faf343185b7cab9c3d55c8ae5471d6d095d3887a4adefdbdf2984dc0b6',
-        'org.apache.httpcomponents:httpclient:4.5.6:httpclient-4.5.6.jar:c03f813195e7a80e3608d0ddd8da80b21696a4c92a6a2298865bf149071551c7',
+        'org.apache.httpcomponents:httpclient:4.5.2:httpclient-4.5.2.jar:0dffc621400d6c632f55787d996b8aeca36b30746a716e079a985f24d8074057',
-        'org.apache.httpcomponents:httpcore:4.4.10:httpcore-4.4.10.jar:78ba1096561957db1b55200a159b648876430342d15d461277e62360da19f6fd',
+        'org.apache.httpcomponents:httpcore:4.4.5:httpcore-4.4.5.jar:64d5453874cab7e40a7065cb01a9a9ca1053845a9786b478878b679e0580cec3',
-        'org.apache.httpcomponents:httpmime:4.5.6:httpmime-4.5.6.jar:0b2b1102c18d3c7e05a77214b9b7501a6f6056174ae5604e0e256776eda7553e',
+        'org.apache.httpcomponents:httpmime:4.5.2:httpmime-4.5.2.jar:231a3f7e4962053db2be8461d5422e68fc458a3a7dd7d8ada803a348e21f8f07',
         'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
         'org.bouncycastle:bcpkix-jdk15on:1.56:bcpkix-jdk15on-1.56.jar:7043dee4e9e7175e93e0b36f45b1ec1ecb893c5f755667e8b916eb8dd201c6ca',
         'org.bouncycastle:bcprov-jdk15on:1.56:bcprov-jdk15on-1.56.jar:963e1ee14f808ffb99897d848ddcdb28fa91ddda867eb18d303e82728f878349',
-        'org.briarproject:obfs4proxy-android:0.0.11-2:obfs4proxy-android-0.0.11-2.zip:57e55cbe87aa2aac210fdbb6cd8cdeafe15f825406a08ebf77a8b787aa2c6a8a',
+        'org.briarproject:obfs4proxy-android:0.0.7:obfs4proxy-android-0.0.7.zip:abdfb5d889d848de9bf214f9276abbf454808a505b870819eccc9a9e985bf617',
-        'org.briarproject:tor-android:0.3.5.9:tor-android-0.3.5.9.zip:853b0440feccd6904bd03e6b2de53a62ebcde1d58068beeadc447a7dff950bc8',
+        'org.briarproject:tor-android:0.3.4.8:tor-android-0.3.4.8.zip:989a0352d9d8d8172cd6c2137654e165e5d2beb10ed1211bab3814e224ad1926',
         'org.checkerframework:checker-compat-qual:2.5.3:checker-compat-qual-2.5.3.jar:d76b9afea61c7c082908023f0cbc1427fab9abd2df915c8b8a3e7a509bccbc6d',
-        'org.checkerframework:checker-qual:2.5.2:checker-qual-2.5.2.jar:64b02691c8b9d4e7700f8ee2e742dce7ea2c6e81e662b7522c9ee3bf568c040a',
+        'org.codehaus.groovy:groovy-all:2.4.12:groovy-all-2.4.12.jar:6a56af4bd48903d56bec62821876cadefafd007360cc6bd0d8f7aa8d72b38be4',
-        'org.codehaus.groovy:groovy-all:2.4.15:groovy-all-2.4.15.jar:51d6c4e71782e85674239189499854359d380fb75e1a703756e3aaa5b98a5af0',
+        'org.codehaus.mojo:animal-sniffer-annotations:1.14:animal-sniffer-annotations-1.14.jar:2068320bd6bad744c3673ab048f67e30bef8f518996fa380033556600669905d',
-        'org.codehaus.mojo:animal-sniffer-annotations:1.17:animal-sniffer-annotations-1.17.jar:92654f493ecfec52082e76354f0ebf87648dc3d5cec2e3c3cdb947c016747a53',
         'org.glassfish.jaxb:jaxb-core:2.2.11:jaxb-core-2.2.11.jar:37bcaee8ebb04362c8352a5bf6221b86967ecdab5164c696b10b9a2bb587b2aa',
         'org.glassfish.jaxb:jaxb-runtime:2.2.11:jaxb-runtime-2.2.11.jar:a874f2351cfba8e2946be3002d10c18a6da8f21b52ba2acf52f2b85d5520ed70',
         'org.glassfish.jaxb:txw2:2.2.11:txw2-2.2.11.jar:272a3ccad45a4511351920cd2a8633c53cab8d5220c7a92954da5526bb5eafea',
         '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.jetbrains.kotlin:kotlin-reflect:1.3.50:kotlin-reflect-1.3.50.jar:64583199ea5a54aefd1bd1595288925f784226ee562d1dd279011c6075b3d7a4',
+        'org.jetbrains.kotlin:kotlin-reflect:1.2.0:kotlin-reflect-1.2.0.jar:4f48a872bad6e4d9c053f4ad610d11e4012ad7e58dc19a03dd5eb811f36069dd',
-        'org.jetbrains.kotlin:kotlin-stdlib-common:1.3.50:kotlin-stdlib-common-1.3.50.jar:8ce678e88e4ba018b66dacecf952471e4d7dfee156a8a819760a5a5ff29d323c',
+        'org.jetbrains.kotlin:kotlin-stdlib-common:1.2.71:kotlin-stdlib-common-1.2.71.jar:63999687ff2fce8a592dd180ffbbf8f1d21c26b4044c55cdc74ff3cf3b3cf328',
-        'org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.3.50:kotlin-stdlib-jdk7-1.3.50.jar:9a026639e76212f8d57b86d55b075394c2e009f1979110751d34c05c5f75d57b',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.2.71:kotlin-stdlib-jdk7-1.2.71.jar:b136bd61b240e07d4d92ce00d3bd1dbf584400a7bf5f220c2f3cd22446858082',
-        'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.3.50:kotlin-stdlib-jdk8-1.3.50.jar:1b351fb6e09c14b55525c74c1f4cf48942eae43c348b7bc764a5e6e423d4da0c',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.2.71:kotlin-stdlib-jdk8-1.2.71.jar:ac3c8abf47790b64b4f7e2509a53f0c145e061ac1612a597520535d199946ea9',
-        'org.jetbrains.kotlin:kotlin-stdlib:1.3.50:kotlin-stdlib-1.3.50.jar:e6f05746ee0366d0b52825a090fac474dcf44082c9083bbb205bd16976488d6c',
+        'org.jetbrains.kotlin:kotlin-stdlib:1.2.71:kotlin-stdlib-1.2.71.jar:4c895c270b87f5fec2a2796e1d89c15407ee821de961527c28588bb46afbc68b',
         'org.jetbrains.trove4j:trove4j:20160824:trove4j-20160824.jar:1917871c8deb468307a584680c87a44572f5a8b0b98c6d397fc0f5f86596dbe7',
         'org.jetbrains:annotations:13.0:annotations-13.0.jar:ace2a10dc8e2d5fd34925ecac03e4988b2c0f851650c94b8cef49ba1bd111478',
         'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',

bramble-api/build.gradle

@@ -7,7 +7,7 @@ apply plugin: 'witness'
 apply from: 'witness.gradle'
 
 dependencies {
-	implementation "com.google.dagger:dagger:2.24"
+	implementation "com.google.dagger:dagger:2.19"
 	implementation 'com.google.code.findbugs:jsr305:3.0.2'
 
 	testImplementation 'junit:junit:4.12'

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

@@ -1,13 +1,14 @@
 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.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 
+import static org.briarproject.bramble.util.StringUtils.toHexString;
+
 /**
  * A wrapper around a byte array, to allow it to be stored in maps etc.
  */
@@ -15,6 +16,8 @@ import javax.annotation.concurrent.ThreadSafe;
 @NotNullByDefault
 public class Bytes implements Comparable<Bytes> {
 
+	public static final BytesComparator COMPARATOR = new BytesComparator();
+
 	private final byte[] bytes;
 
 	private int hashCode = -1;
@@ -36,28 +39,32 @@ public class Bytes implements Comparable<Bytes> {
 	}
 
 	@Override
-	public boolean equals(@Nullable Object o) {
+	public boolean equals(Object o) {
 		return o instanceof Bytes && Arrays.equals(bytes, ((Bytes) o).bytes);
 	}
 
 	@Override
 	public int compareTo(Bytes other) {
-		return compare(bytes, other.bytes);
+		byte[] aBytes = bytes, bBytes = other.bytes;
+		int length = Math.min(aBytes.length, bBytes.length);
+		for (int i = 0; i < length; i++) {
+			int aUnsigned = aBytes[i] & 0xFF, bUnsigned = bBytes[i] & 0xFF;
+			if (aUnsigned < bUnsigned) return -1;
+			if (aUnsigned > bUnsigned) return 1;
+		}
+		return aBytes.length - bBytes.length;
 	}
 
 	@Override
 	public String toString() {
-		return getClass().getSimpleName() +
+		return getClass().getSimpleName() + "(" + toHexString(getBytes()) + ")";
-				"(" + StringUtils.toHexString(getBytes()) + ")";
 	}
 
-	public static int compare(byte[] a, byte[] b) {
+	public static class BytesComparator implements Comparator<Bytes> {
-		int length = Math.min(a.length, b.length);
+
-		for (int i = 0; i < length; i++) {
+		@Override
-			int aUnsigned = a[i] & 0xFF, bUnsigned = b[i] & 0xFF;
+		public int compare(Bytes a, Bytes b) {
-			if (aUnsigned < bUnsigned) return -1;
+			return a.compareTo(b);
-			if (aUnsigned > bUnsigned) return 1;
 		}
-		return a.length - b.length;
 	}
 }

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

@@ -1,9 +0,0 @@
-package org.briarproject.bramble.api;
-
-/**
- * Interface for specifying which features are enabled in a build.
- */
-public interface FeatureFlags {
-
-	boolean shouldEnableImageAttachments();
-}

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

@@ -2,7 +2,6 @@ package org.briarproject.bramble.api;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.NoSuchElementException;
@@ -10,6 +9,8 @@ import java.util.Set;
 
 import javax.annotation.concurrent.NotThreadSafe;
 
+import static java.util.Collections.unmodifiableSet;
+
 @NotThreadSafe
 @NotNullByDefault
 public class Multiset<T> {
@@ -96,6 +97,6 @@ public class Multiset<T> {
 	 * is unmodifiable.
 	 */
 	public Set<T> keySet() {
-		return Collections.unmodifiableSet(map.keySet());
+		return unmodifiableSet(map.keySet());
 	}
 }

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

@@ -1,9 +0,0 @@
-package org.briarproject.bramble.api;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-@NotNullByDefault
-public interface Predicate<T> {
-
-	boolean test(T t);
-}

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

@@ -1,18 +0,0 @@
-package org.briarproject.bramble.api;
-
-/**
- * Thrown when data being parsed uses a protocol or format version that is not
- * supported.
- */
-public class UnsupportedVersionException extends FormatException {
-
-	private final boolean tooOld;
-
-	public UnsupportedVersionException(boolean tooOld) {
-		this.tooOld = tooOld;
-	}
-
-	public boolean isTooOld() {
-		return tooOld;
-	}
-}

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

@@ -33,8 +33,7 @@ public abstract class BdfIncomingMessageHook implements IncomingMessageHook {
 	/**
 	 * Called once for each incoming message that passes validation.
 	 *
-	 * @param txn A read-write transaction
+	 * @return whether or not this message should be shared
-	 * @return Whether or not this message should be shared
 	 * @throws DbException Should only be used for real database errors.
 	 * If this is thrown, delivery will be attempted again at next startup,
 	 * whereas if a FormatException is thrown, the message will be permanently

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

@@ -5,10 +5,11 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.MessageId;
 
 import java.util.Collection;
-import java.util.Collections;
 
 import javax.annotation.concurrent.Immutable;
 
+import static java.util.Collections.emptyList;
+
 @Immutable
 @NotNullByDefault
 public class BdfMessageContext {
@@ -23,7 +24,7 @@ public class BdfMessageContext {
 	}
 
 	public BdfMessageContext(BdfDictionary dictionary) {
-		this(dictionary, Collections.emptyList());
+		this(dictionary, emptyList());
 	}
 
 	public BdfDictionary getDictionary() {

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

@@ -16,6 +16,7 @@ import java.util.logging.Logger;
 
 import javax.annotation.concurrent.Immutable;
 
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.transport.TransportConstants.MAX_CLOCK_DIFFERENCE;
 
 @Immutable
@@ -23,7 +24,7 @@ import static org.briarproject.bramble.api.transport.TransportConstants.MAX_CLOC
 public abstract class BdfMessageValidator implements MessageValidator {
 
 	protected static final Logger LOG =
-			Logger.getLogger(BdfMessageValidator.class.getName());
+			getLogger(BdfMessageValidator.class.getName());
 
 	protected final ClientHelper clientHelper;
 	protected final MetadataEncoder metadataEncoder;

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

@@ -1,8 +1,6 @@
 package org.briarproject.bramble.api.client;
 
 import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.crypto.PrivateKey;
-import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.data.BdfDictionary;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.db.DbException;
@@ -25,10 +23,7 @@ public interface ClientHelper {
 			throws DbException, FormatException;
 
 	void addLocalMessage(Transaction txn, Message m, BdfDictionary metadata,
-			boolean shared, boolean temporary)
+			boolean shared) throws DbException, FormatException;
-			throws DbException, FormatException;
-
-	Message createMessage(GroupId g, long timestamp, byte[] body);
 
 	Message createMessage(GroupId g, long timestamp, BdfList body)
 			throws FormatException;
@@ -101,18 +96,14 @@ public interface ClientHelper {
 
 	BdfList toList(Author a);
 
-	byte[] sign(String label, BdfList toSign, PrivateKey privateKey)
+	byte[] sign(String label, BdfList toSign, byte[] privateKey)
 			throws FormatException, GeneralSecurityException;
 
 	void verifySignature(byte[] signature, String label, BdfList signed,
-			PublicKey publicKey)
+			byte[] publicKey) throws FormatException, GeneralSecurityException;
-			throws FormatException, GeneralSecurityException;
 
 	Author parseAndValidateAuthor(BdfList author) throws FormatException;
 
-	PublicKey parseAndValidateAgreementPublicKey(byte[] publicKeyBytes)
-			throws FormatException;
-
 	TransportProperties parseAndValidateTransportProperties(
 			BdfDictionary properties) throws FormatException;
 

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

@@ -1,6 +1,5 @@
 package org.briarproject.bramble.api.contact;
 
-import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
@@ -20,13 +19,10 @@ public class Contact {
 	private final AuthorId localAuthorId;
 	@Nullable
 	private final String alias;
-	@Nullable
+	private final boolean verified, active;
-	private final PublicKey handshakePublicKey;
-	private final boolean verified;
 
 	public Contact(ContactId id, Author author, AuthorId localAuthorId,
-			@Nullable String alias, @Nullable PublicKey handshakePublicKey,
+			@Nullable String alias, boolean verified, boolean active) {
-			boolean verified) {
 		if (alias != null) {
 			int aliasLength = toUtf8(alias).length;
 			if (aliasLength == 0 || aliasLength > MAX_AUTHOR_NAME_LENGTH)
@@ -36,8 +32,8 @@ public class Contact {
 		this.author = author;
 		this.localAuthorId = localAuthorId;
 		this.alias = alias;
-		this.handshakePublicKey = handshakePublicKey;
 		this.verified = verified;
+		this.active = active;
 	}
 
 	public ContactId getId() {
@@ -57,15 +53,14 @@ public class Contact {
 		return alias;
 	}
 
-	@Nullable
-	public PublicKey getHandshakePublicKey() {
-		return handshakePublicKey;
-	}
-
 	public boolean isVerified() {
 		return verified;
 	}
 
+	public boolean isActive() {
+		return active;
+	}
+
 	@Override
 	public int hashCode() {
 		return id.hashCode();

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/ContactExchangeManager.java

@@ -1,37 +0,0 @@
-package org.briarproject.bramble.api.contact;
-
-import org.briarproject.bramble.api.crypto.SecretKey;
-import org.briarproject.bramble.api.db.ContactExistsException;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-
-import java.io.IOException;
-
-@NotNullByDefault
-public interface ContactExchangeManager {
-
-	/**
-	 * Exchanges contact information with a remote peer and adds the peer
-	 * as a contact.
-	 *
-	 * @param alice Whether the local peer takes the role of Alice
-	 * @return The newly added contact
-	 * @throws ContactExistsException If the contact already exists
-	 */
-	Contact exchangeContacts(DuplexTransportConnection conn,
-			SecretKey masterKey, boolean alice, boolean verified)
-			throws IOException, DbException;
-
-	/**
-	 * Exchanges contact information with a remote peer and adds the peer
-	 * as a contact, replacing the given pending contact.
-	 *
-	 * @param alice Whether the local peer takes the role of Alice
-	 * @return The newly added contact
-	 * @throws ContactExistsException If the contact already exists
-	 */
-	Contact exchangeContacts(PendingContactId p, DuplexTransportConnection conn,
-			SecretKey masterKey, boolean alice, boolean verified)
-			throws IOException, DbException;
-}

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

@@ -0,0 +1,48 @@
+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 {
+
+	/**
+	 * The current version of the contact exchange protocol.
+	 */
+	byte PROTOCOL_VERSION = 1;
+
+	/**
+	 * Label for deriving Alice's header key from the master secret.
+	 */
+	String ALICE_KEY_LABEL =
+			"org.briarproject.bramble.contact/ALICE_HEADER_KEY";
+
+	/**
+	 * Label for deriving Bob's header key from the master secret.
+	 */
+	String BOB_KEY_LABEL = "org.briarproject.bramble.contact/BOB_HEADER_KEY";
+
+	/**
+	 * Label for deriving Alice's key binding nonce from the master secret.
+	 */
+	String ALICE_NONCE_LABEL = "org.briarproject.bramble.contact/ALICE_NONCE";
+
+	/**
+	 * Label for deriving Bob's key binding nonce from the master secret.
+	 */
+	String BOB_NONCE_LABEL = "org.briarproject.bramble.contact/BOB_NONCE";
+
+	/**
+	 * Exchanges contact information with a remote peer.
+	 */
+	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

@@ -2,7 +2,6 @@ package org.briarproject.bramble.api.contact;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
-import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 
 /**
@@ -29,7 +28,7 @@ public class ContactId {
 	}
 
 	@Override
-	public boolean equals(@Nullable Object o) {
+	public boolean equals(Object o) {
 		return o instanceof ContactId && id == ((ContactId) o).id;
 	}
 }

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

@@ -1,13 +1,7 @@
 package org.briarproject.bramble.api.contact;
 
-import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.Pair;
-import org.briarproject.bramble.api.UnsupportedVersionException;
 import org.briarproject.bramble.api.crypto.SecretKey;
-import org.briarproject.bramble.api.db.ContactExistsException;
 import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.db.NoSuchContactException;
-import org.briarproject.bramble.api.db.PendingContactExistsException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
@@ -15,11 +9,12 @@ import org.briarproject.bramble.api.identity.AuthorInfo;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
-import java.security.GeneralSecurityException;
 import java.util.Collection;
 
 import javax.annotation.Nullable;
 
+import static org.briarproject.bramble.api.contact.PendingContact.PendingContactState.FAILED;
+
 @NotNullByDefault
 public interface ContactManager {
 
@@ -32,119 +27,61 @@ public interface ContactManager {
 
 	/**
 	 * Stores a contact associated with the given local and remote pseudonyms,
-	 * derives and stores rotation mode transport keys for each transport, and
+	 * derives and stores transport keys for each transport, and returns an ID
-	 * returns an ID for the contact.
-	 *
-	 * @param rootKey The root key for a set of rotation mode transport keys
-	 * @param timestamp The timestamp for deriving rotation mode transport
-	 * keys from the root key
-	 * @param alice True if the local party is Alice
-	 * @param verified True if the contact's identity has been verified, which
-	 * is true if the contact was added in person or false if the contact was
-	 * introduced or added remotely
-	 * @param active True if the rotation mode transport keys can be used for
-	 * outgoing streams
-	 */
-	ContactId addContact(Transaction txn, Author remote, AuthorId local,
-			SecretKey rootKey, long timestamp, boolean alice, boolean verified,
-			boolean active) throws DbException;
-
-	/**
-	 * Stores a contact associated with the given local and remote pseudonyms,
-	 * replacing the given pending contact, derives and stores handshake mode
-	 * and rotation mode transport keys for each transport, and returns an ID
 	 * for the contact.
 	 *
-	 * @param rootKey The root key for a set of rotation mode transport keys
+	 * @param alice true if the local party is Alice
-	 * @param timestamp The timestamp for deriving rotation mode transport
-	 * keys from the root key
-	 * @param alice True if the local party is Alice
-	 * @param verified True if the contact's identity has been verified, which
-	 * is true if the contact was added in person or false if the contact was
-	 * introduced or added remotely
-	 * @param active True if the rotation mode transport keys can be used for
-	 * outgoing streams
-	 * @throws GeneralSecurityException If the pending contact's handshake
-	 * public key is invalid
 	 */
-	ContactId addContact(Transaction txn, PendingContactId p, Author remote,
+	ContactId addContact(Transaction txn, Author remote, AuthorId local,
-			AuthorId local, SecretKey rootKey, long timestamp, boolean alice,
+			SecretKey master, long timestamp, boolean alice, boolean verified,
-			boolean verified, boolean active)
+			boolean active) throws DbException;
-			throws DbException, GeneralSecurityException;
 
 	/**
 	 * Stores a contact associated with the given local and remote pseudonyms
 	 * and returns an ID for the contact.
-	 *
-	 * @param verified True if the contact's identity has been verified, which
-	 * is true if the contact was added in person or false if the contact was
-	 * introduced or added remotely
 	 */
 	ContactId addContact(Transaction txn, Author remote, AuthorId local,
-			boolean verified) throws DbException;
+			boolean verified, boolean active) throws DbException;
 
 	/**
 	 * Stores a contact associated with the given local and remote pseudonyms,
-	 * derives and stores rotation mode transport keys for each transport, and
+	 * derives and stores transport keys for each transport, and returns an ID
-	 * returns an ID for the contact.
+	 * for the contact.
 	 *
-	 * @param rootKey The root key for a set of rotation mode transport keys
+	 * @param alice true if the local party is Alice
-	 * @param timestamp The timestamp for deriving rotation mode transport
-	 * keys from the root key
-	 * @param alice True if the local party is Alice
-	 * @param verified True if the contact's identity has been verified, which
-	 * is true if the contact was added in person or false if the contact was
-	 * introduced or added remotely
-	 * @param active True if the rotation mode transport keys can be used for
-	 * outgoing streams
 	 */
-	ContactId addContact(Author remote, AuthorId local, SecretKey rootKey,
+	ContactId addContact(Author remote, AuthorId local, SecretKey master,
 			long timestamp, boolean alice, boolean verified, boolean active)
 			throws DbException;
 
 	/**
-	 * Returns the handshake link that needs to be sent to a contact we want
+	 * Returns the static link that needs to be sent to the contact to be added.
-	 * to add.
 	 */
-	String getHandshakeLink() throws DbException;
+	String getRemoteContactLink();
 
 	/**
-	 * Creates a {@link PendingContact} from the given handshake link and
+	 * Returns true if the given link is syntactically valid.
-	 * alias, adds it to the database and returns it.
+	 */
+	boolean isValidRemoteContactLink(String link);
+
+	/**
+	 * Requests a new contact to be added via the given {@code link}.
 	 *
-	 * @param link The handshake link received from the pending contact
+	 * @param link The link received from the contact we want to add.
-	 * @param alias The alias the user has given this pending contact
+	 * @param alias The alias the user has given this contact.
-	 * @throws UnsupportedVersionException If the link uses a format version
+	 * @return A PendingContact representing the contact to be added.
-	 * that is not supported
-	 * @throws FormatException If the link is invalid
-	 * @throws GeneralSecurityException If the pending contact's handshake
-	 * public key is invalid
-	 * @throws ContactExistsException If a contact with the same handshake
-	 * public key already exists
-	 * @throws PendingContactExistsException If a pending contact with the same
-	 * handshake public key already exists
 	 */
-	PendingContact addPendingContact(String link, String alias)
+	PendingContact addRemoteContactRequest(String link, String alias);
-			throws DbException, FormatException, GeneralSecurityException,
-			ContactExistsException, PendingContactExistsException;
 
 	/**
-	 * Returns the pending contact with the given ID.
+	 * Returns a list of {@link PendingContact}s.
 	 */
-	PendingContact getPendingContact(Transaction txn, PendingContactId p)
+	Collection<PendingContact> getPendingContacts();
-			throws DbException;
 
 	/**
-	 * Returns a list of {@link PendingContact PendingContacts} and their
+	 * Removes a {@link PendingContact} that is in state {@link FAILED}.
-	 * {@link PendingContactState states}.
 	 */
-	Collection<Pair<PendingContact, PendingContactState>> getPendingContacts()
+	void removePendingContact(PendingContact pendingContact);
-			throws DbException;
-
-	/**
-	 * Removes a {@link PendingContact}.
-	 */
-	void removePendingContact(PendingContactId p) throws DbException;
 
 	/**
 	 * Returns the contact with the given ID.
@@ -152,32 +89,27 @@ public interface ContactManager {
 	Contact getContact(ContactId c) throws DbException;
 
 	/**
-	 * Returns the contact with the given ID.
+	 * Returns the contact with the given remoteAuthorId
-	 */
+	 * that was added by the LocalAuthor with the given localAuthorId
-	Contact getContact(Transaction txn, ContactId c) throws DbException;
-
-	/**
-	 * Returns the contact with the given {@code remoteAuthorId}
-	 * that belongs to the local pseudonym with the given {@code localAuthorId}.
 	 *
-	 * @throws NoSuchContactException If the contact is not in the database
+	 * @throws org.briarproject.bramble.api.db.NoSuchContactException
 	 */
 	Contact getContact(AuthorId remoteAuthorId, AuthorId localAuthorId)
 			throws DbException;
 
 	/**
-	 * Returns the contact with the given {@code remoteAuthorId}
+	 * Returns the contact with the given remoteAuthorId
-	 * that belongs to the local pseudonym with the given {@code localAuthorId}.
+	 * that was added by the LocalAuthor with the given localAuthorId
 	 *
-	 * @throws NoSuchContactException If the contact is not in the database
+	 * @throws org.briarproject.bramble.api.db.NoSuchContactException
 	 */
 	Contact getContact(Transaction txn, AuthorId remoteAuthorId,
 			AuthorId localAuthorId) throws DbException;
 
 	/**
-	 * Returns all contacts.
+	 * Returns all active contacts.
 	 */
-	Collection<Contact> getContacts() throws DbException;
+	Collection<Contact> getActiveContacts() throws DbException;
 
 	/**
 	 * Removes a contact and all associated state.
@@ -190,27 +122,31 @@ public interface ContactManager {
 	void removeContact(Transaction txn, ContactId c) throws DbException;
 
 	/**
-	 * Sets an alias for the contact or unsets it if {@code alias} is null.
+	 * Marks a contact as active or inactive.
+	 */
+	void setContactActive(Transaction txn, ContactId c, boolean active)
+			throws DbException;
+
+	/**
+	 * Sets an alias name for the contact or unsets it if alias is null.
 	 */
 	void setContactAlias(Transaction txn, ContactId c, @Nullable String alias)
 			throws DbException;
 
 	/**
-	 * Sets an alias for the contact or unsets it if {@code alias} is null.
+	 * Sets an alias name for the contact or unsets it if alias is null.
 	 */
 	void setContactAlias(ContactId c, @Nullable String alias)
 			throws DbException;
 
 	/**
-	 * Returns true if a contact with this {@code remoteAuthorId} belongs to
+	 * Return true if a contact with this name and public key already exists
-	 * the local pseudonym with this {@code localAuthorId}.
 	 */
 	boolean contactExists(Transaction txn, AuthorId remoteAuthorId,
 			AuthorId localAuthorId) throws DbException;
 
 	/**
-	 * Returns true if a contact with this {@code remoteAuthorId} belongs to
+	 * Return true if a contact with this name and public key already exists
-	 * the local pseudonym with this {@code localAuthorId}.
 	 */
 	boolean contactExists(AuthorId remoteAuthorId, AuthorId localAuthorId)
 			throws DbException;
@@ -227,20 +163,8 @@ public interface ContactManager {
 
 	interface ContactHook {
 
-		/**
-		 * Called when a contact is being added.
-		 *
-		 * @param txn A read-write transaction
-		 * @param c The contact that is being added
-		 */
 		void addingContact(Transaction txn, Contact c) throws DbException;
 
-		/**
-		 * Called when a contact is being removed
-		 *
-		 * @param txn A read-write transaction
-		 * @param c The contact that is being removed
-		 */
 		void removingContact(Transaction txn, Contact c) throws DbException;
 	}
 }

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

@@ -1,34 +0,0 @@
-package org.briarproject.bramble.api.contact;
-
-import java.util.regex.Pattern;
-
-public interface HandshakeLinkConstants {
-
-	/**
-	 * The current version of the handshake link format.
-	 */
-	int FORMAT_VERSION = 0;
-
-	/**
-	 * The length of a base32-encoded handshake link in bytes, excluding the
-	 * 'briar://' prefix.
-	 */
-	int BASE32_LINK_BYTES = 53;
-
-	/**
-	 * The length of a raw handshake link in bytes, before base32 encoding.
-	 */
-	int RAW_LINK_BYTES = 33;
-
-	/**
-	 * Regular expression for matching handshake links, including or excluding
-	 * the 'briar://' prefix.
-	 */
-	Pattern LINK_REGEX =
-			Pattern.compile("(briar://)?([a-z2-7]{" + BASE32_LINK_BYTES + "})");
-
-	/**
-	 * Label for hashing handshake public keys to calculate their identifiers.
-	 */
-	String ID_LABEL = "org.briarproject.bramble/HANDSHAKE_KEY_ID";
-}

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

@@ -1,45 +0,0 @@
-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.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.transport.StreamWriter;
-
-import java.io.IOException;
-import java.io.InputStream;
-
-@NotNullByDefault
-public interface HandshakeManager {
-
-	/**
-	 * Handshakes with the given pending contact. Returns an ephemeral master
-	 * key authenticated with both parties' handshake key pairs and a flag
-	 * indicating whether the local peer is Alice or Bob.
-	 *
-	 * @param in An incoming stream for the handshake, which must be secured in
-	 * handshake mode
-	 * @param out An outgoing stream for the handshake, which must be secured
-	 * in handshake mode
-	 */
-	HandshakeResult handshake(PendingContactId p, InputStream in,
-			StreamWriter out) throws DbException, IOException;
-
-	class HandshakeResult {
-
-		private final SecretKey masterKey;
-		private final boolean alice;
-
-		public HandshakeResult(SecretKey masterKey, boolean alice) {
-			this.masterKey = masterKey;
-			this.alice = alice;
-		}
-
-		public SecretKey getMasterKey() {
-			return masterKey;
-		}
-
-		public boolean isAlice() {
-			return alice;
-		}
-	}
-}

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

@@ -1,6 +1,5 @@
 package org.briarproject.bramble.api.contact;
 
-import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import javax.annotation.concurrent.Immutable;
@@ -9,31 +8,34 @@ import javax.annotation.concurrent.Immutable;
 @NotNullByDefault
 public class PendingContact {
 
+	public enum PendingContactState {
+		WAITING_FOR_CONNECTION,
+		CONNECTED,
+		ADDING_CONTACT,
+		FAILED
+	}
+
 	private final PendingContactId id;
-	private final PublicKey publicKey;
 	private final String alias;
+	private final PendingContactState state;
 	private final long timestamp;
 
-	public PendingContact(PendingContactId id, PublicKey publicKey,
+	public PendingContact(PendingContactId id, String alias,
-			String alias, long timestamp) {
+			PendingContactState state, long timestamp) {
 		this.id = id;
-		this.publicKey = publicKey;
 		this.alias = alias;
+		this.state = state;
 		this.timestamp = timestamp;
 	}
 
-	public PendingContactId getId() {
-		return id;
-	}
-
-	public PublicKey getPublicKey() {
-		return publicKey;
-	}
-
 	public String getAlias() {
 		return alias;
 	}
 
+	public PendingContactState getState() {
+		return state;
+	}
+
 	public long getTimestamp() {
 		return timestamp;
 	}
@@ -48,4 +50,5 @@ public class PendingContact {
 		return o instanceof PendingContact &&
 				id.equals(((PendingContact) o).id);
 	}
+
 }

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

@@ -1,25 +1,11 @@
 package org.briarproject.bramble.api.contact;
 
 import org.briarproject.bramble.api.UniqueId;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
-import javax.annotation.Nullable;
-import javax.annotation.concurrent.ThreadSafe;
-
-/**
- * Type-safe wrapper for a byte array that uniquely identifies a
- * {@link PendingContact}.
- */
-@ThreadSafe
-@NotNullByDefault
 public class PendingContactId extends UniqueId {
 
 	public PendingContactId(byte[] id) {
 		super(id);
 	}
 
-	@Override
-	public boolean equals(@Nullable Object o) {
-		return o instanceof PendingContactId && super.equals(o);
-	}
 }

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

@@ -1,10 +0,0 @@
-package org.briarproject.bramble.api.contact;
-
-public enum PendingContactState {
-
-	WAITING_FOR_CONNECTION,
-	OFFLINE,
-	CONNECTING,
-	ADDING_CONTACT,
-	FAILED
-}

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

@@ -1,9 +1,9 @@
-package org.briarproject.bramble.contact;
+package org.briarproject.bramble.api.contact;
 
 /**
  * Record types for the contact exchange protocol.
  */
-interface ContactExchangeRecordTypes {
+public interface RecordTypes {
 
 	byte CONTACT_INFO = 0;
 }

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

@@ -14,18 +14,18 @@ import javax.annotation.concurrent.Immutable;
 public class ContactAddedEvent extends Event {
 
 	private final ContactId contactId;
-	private final boolean verified;
+	private final boolean active;
 
-	public ContactAddedEvent(ContactId contactId, boolean verified) {
+	public ContactAddedEvent(ContactId contactId, boolean active) {
 		this.contactId = contactId;
-		this.verified = verified;
+		this.active = active;
 	}
 
 	public ContactId getContactId() {
 		return contactId;
 	}
 
-	public boolean isVerified() {
+	public boolean isActive() {
-		return verified;
+		return active;
 	}
 }

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/PendingContactAddedEvent.java

@@ -1,25 +0,0 @@
-package org.briarproject.bramble.api.contact.event;
-
-import org.briarproject.bramble.api.contact.PendingContact;
-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 pending contact is added.
- */
-@Immutable
-@NotNullByDefault
-public class PendingContactAddedEvent extends Event {
-
-	private final PendingContact pendingContact;
-
-	public PendingContactAddedEvent(PendingContact pendingContact) {
-		this.pendingContact = pendingContact;
-	}
-
-	public PendingContact getPendingContact() {
-		return pendingContact;
-	}
-}

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

@@ -1,26 +0,0 @@
-package org.briarproject.bramble.api.contact.event;
-
-import org.briarproject.bramble.api.contact.PendingContactId;
-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 pending contact is removed.
- */
-@Immutable
-@NotNullByDefault
-public class PendingContactRemovedEvent extends Event {
-
-	private final PendingContactId id;
-
-	public PendingContactRemovedEvent(PendingContactId id) {
-		this.id = id;
-	}
-
-	public PendingContactId getId() {
-		return id;
-	}
-
-}

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

@@ -1,7 +1,7 @@
 package org.briarproject.bramble.api.contact.event;
 
+import org.briarproject.bramble.api.contact.PendingContact.PendingContactState;
 import org.briarproject.bramble.api.contact.PendingContactId;
-import org.briarproject.bramble.api.contact.PendingContactState;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 

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

@@ -1,30 +0,0 @@
-package org.briarproject.bramble.api.crypto;
-
-import org.briarproject.bramble.api.Bytes;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-import static org.briarproject.bramble.api.crypto.CryptoConstants.KEY_TYPE_AGREEMENT;
-
-/**
- * Type-safe wrapper for a private key used for key agreement.
- */
-@Immutable
-@NotNullByDefault
-public class AgreementPrivateKey extends Bytes implements PrivateKey {
-
-	public AgreementPrivateKey(byte[] encoded) {
-		super(encoded);
-	}
-
-	@Override
-	public String getKeyType() {
-		return KEY_TYPE_AGREEMENT;
-	}
-
-	@Override
-	public byte[] getEncoded() {
-		return getBytes();
-	}
-}

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

@@ -1,35 +0,0 @@
-package org.briarproject.bramble.api.crypto;
-
-import org.briarproject.bramble.api.Bytes;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-import static org.briarproject.bramble.api.crypto.CryptoConstants.KEY_TYPE_AGREEMENT;
-import static org.briarproject.bramble.api.crypto.CryptoConstants.MAX_AGREEMENT_PUBLIC_KEY_BYTES;
-
-/**
- * Type-safe wrapper for a public key used for key agreement.
- */
-@Immutable
-@NotNullByDefault
-public class AgreementPublicKey extends Bytes implements PublicKey {
-
-	public AgreementPublicKey(byte[] encoded) {
-		super(encoded);
-		if (encoded.length == 0 ||
-				encoded.length > MAX_AGREEMENT_PUBLIC_KEY_BYTES) {
-			throw new IllegalArgumentException();
-		}
-	}
-
-	@Override
-	public String getKeyType() {
-		return KEY_TYPE_AGREEMENT;
-	}
-
-	@Override
-	public byte[] getEncoded() {
-		return getBytes();
-	}
-}

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

@@ -27,78 +27,54 @@ public interface CryptoComponent {
 	/**
 	 * Derives another secret key from the given secret key.
 	 *
-	 * @param label A namespaced label indicating the purpose of the derived
+	 * @param label a namespaced label indicating the purpose of the derived
 	 * key, to prevent it from being repurposed or colliding with a key derived
 	 * for another purpose
-	 * @param inputs Additional inputs that will be included in the derivation
-	 * of the key
 	 */
 	SecretKey deriveKey(String label, SecretKey k, byte[]... inputs);
 
 	/**
-	 * Derives a shared secret from two key pairs.
+	 * Derives a common shared secret from two public keys and one of the
+	 * corresponding private keys.
 	 *
-	 * @param label A namespaced label indicating the purpose of this shared
+	 * @param label a namespaced label indicating the purpose of this shared
 	 * secret, to prevent it from being repurposed or colliding with a shared
 	 * secret derived for another purpose
-	 * @param theirPublicKey The public key of the remote party
+	 * @param theirPublicKey the public key of the remote party
-	 * @param ourKeyPair The key pair of the local party
+	 * @param ourKeyPair the key pair of the local party
-	 * @param inputs Additional inputs that will be included in the derivation
+	 * @return the shared secret
-	 * of the shared secret
-	 * @return The shared secret
 	 */
 	SecretKey deriveSharedSecret(String label, PublicKey theirPublicKey,
 			KeyPair ourKeyPair, byte[]... inputs)
 			throws GeneralSecurityException;
 
-	/**
-	 * Derives a shared secret from two static and two ephemeral key pairs.
-	 *
-	 * @param label A namespaced label indicating the purpose of this shared
-	 * secret, to prevent it from being repurposed or colliding with a shared
-	 * secret derived for another purpose
-	 * @param theirStaticPublicKey The static public key of the remote party
-	 * @param theirEphemeralPublicKey The ephemeral public key of the remote
-	 * party
-	 * @param ourStaticKeyPair The static key pair of the local party
-	 * @param ourEphemeralKeyPair The ephemeral key pair of the local party
-	 * @param alice True if the local party is Alice
-	 * @param inputs Additional inputs that will be included in the
-	 * derivation of the shared secret
-	 * @return The shared secret
-	 */
-	SecretKey deriveSharedSecret(String label, PublicKey theirStaticPublicKey,
-			PublicKey theirEphemeralPublicKey, KeyPair ourStaticKeyPair,
-			KeyPair ourEphemeralKeyPair, boolean alice, byte[]... inputs)
-			throws GeneralSecurityException;
-
 	/**
 	 * Signs the given byte[] with the given private key.
 	 *
-	 * @param label A namespaced label indicating the purpose of this
+	 * @param label a namespaced label indicating the purpose of this
 	 * signature, to prevent it from being repurposed or colliding with a
 	 * signature created for another purpose
 	 */
-	byte[] sign(String label, byte[] toSign, PrivateKey privateKey)
+	byte[] sign(String label, byte[] toSign, byte[] privateKey)
 			throws GeneralSecurityException;
 
 	/**
 	 * Verifies that the given signature is valid for the signed data
 	 * and the given public key.
 	 *
-	 * @param label A namespaced label indicating the purpose of this
+	 * @param label a namespaced label indicating the purpose of this
 	 * signature, to prevent it from being repurposed or colliding with a
 	 * signature created for another purpose
-	 * @return True if the signature was valid, false otherwise.
+	 * @return true if the signature was valid, false otherwise.
 	 */
 	boolean verifySignature(byte[] signature, String label, byte[] signed,
-			PublicKey publicKey) throws GeneralSecurityException;
+			byte[] publicKey) throws GeneralSecurityException;
 
 	/**
 	 * Returns the hash of the given inputs. The inputs are unambiguously
 	 * combined by prefixing each input with its length.
 	 *
-	 * @param label A namespaced label indicating the purpose of this hash, to
+	 * @param label a namespaced label indicating the purpose of this hash, to
 	 * prevent it from being repurposed or colliding with a hash created for
 	 * another purpose
 	 */
@@ -109,7 +85,7 @@ public interface CryptoComponent {
 	 * given inputs. The inputs are unambiguously combined by prefixing each
 	 * input with its length.
 	 *
-	 * @param label A namespaced label indicating the purpose of this MAC, to
+	 * @param label a namespaced label indicating the purpose of this MAC, to
 	 * prevent it from being repurposed or colliding with a MAC created for
 	 * another purpose
 	 */
@@ -119,10 +95,10 @@ public interface CryptoComponent {
 	 * Verifies that the given message authentication code is valid for the
 	 * given secret key and inputs.
 	 *
-	 * @param label A namespaced label indicating the purpose of this MAC, to
+	 * @param label a namespaced label indicating the purpose of this MAC, to
 	 * prevent it from being repurposed or colliding with a MAC created for
 	 * another purpose
-	 * @return True if the MAC was valid, false otherwise.
+	 * @return true if the MAC was valid, false otherwise.
 	 */
 	boolean verifyMac(byte[] mac, String label, SecretKey macKey,
 			byte[]... inputs);
@@ -132,32 +108,17 @@ public interface CryptoComponent {
 	 * storage. The encryption and authentication keys are derived from the
 	 * given password. The ciphertext will be decryptable using the same
 	 * password after the app restarts.
-	 *
-	 * @param keyStrengthener Used to strengthen the password-based key. If
-	 * null, the password-based key will not be strengthened
 	 */
-	byte[] encryptWithPassword(byte[] plaintext, String password,
+	byte[] encryptWithPassword(byte[] plaintext, String password);
-			@Nullable KeyStrengthener keyStrengthener);
 
 	/**
 	 * Decrypts and authenticates the given ciphertext that has been read from
 	 * storage. The encryption and authentication keys are derived from the
 	 * given password. Returns null if the ciphertext cannot be decrypted and
 	 * authenticated (for example, if the password is wrong).
-	 *
-	 * @param keyStrengthener Used to strengthen the password-based key. If
-	 * null, or if strengthening was not used when encrypting the ciphertext,
-	 * the password-based key will not be strengthened
 	 */
 	@Nullable
-	byte[] decryptWithPassword(byte[] ciphertext, String password,
+	byte[] decryptWithPassword(byte[] ciphertext, String password);
-			@Nullable KeyStrengthener keyStrengthener);
-
-	/**
-	 * Returns true if the given ciphertext was encrypted using a strengthened
-	 * key. The validity of the ciphertext is not checked.
-	 */
-	boolean isEncryptedWithStrengthenedKey(byte[] ciphertext);
 
 	/**
 	 * Encrypts the given plaintext to the given public key.

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

@@ -7,21 +7,11 @@ public interface CryptoConstants {
 	 */
 	int MAX_AGREEMENT_PUBLIC_KEY_BYTES = 32;
 
-	/**
-	 * The key type for agreement key pairs.
-	 */
-	String KEY_TYPE_AGREEMENT = "Curve25519";
-
 	/**
 	 * The maximum length of a signature public key in bytes.
 	 */
 	int MAX_SIGNATURE_PUBLIC_KEY_BYTES = 32;
 
-	/**
-	 * The key type for signature key pairs.
-	 */
-	String KEY_TYPE_SIGNATURE = "Ed25519";
-
 	/**
 	 * The maximum length of a signature in bytes.
 	 */

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

@@ -2,7 +2,7 @@ package org.briarproject.bramble.api.crypto;
 
 /**
  * Crypto operations for the key agreement protocol - see
- * https://code.briarproject.org/briar/briar-spec/blob/master/protocols/BQP.md
+ * https://code.briarproject.org/akwizgran/briar-spec/blob/master/protocols/BQP.md
  */
 public interface KeyAgreementCrypto {
 

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

@@ -15,8 +15,6 @@ public class KeyPair {
 	private final PrivateKey privateKey;
 
 	public KeyPair(PublicKey publicKey, PrivateKey privateKey) {
-		if (!publicKey.getKeyType().equals(privateKey.getKeyType()))
-			throw new IllegalArgumentException();
 		this.publicKey = publicKey;
 		this.privateKey = privateKey;
 	}

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

@@ -1,23 +0,0 @@
-package org.briarproject.bramble.api.crypto;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-/**
- * Interface for strengthening a password-based key, for example by using a
- * key stored in a key management service or hardware security module.
- */
-@NotNullByDefault
-public interface KeyStrengthener {
-
-	/**
-	 * Returns true if the strengthener has been initialised.
-	 */
-	@SuppressWarnings("BooleanMethodIsAlwaysInverted")
-	boolean isInitialised();
-
-	/**
-	 * Initialises the strengthener if necessary and returns a strong key
-	 * derived from the given key.
-	 */
-	SecretKey strengthenKey(SecretKey k);
-}

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

@@ -8,11 +8,6 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 @NotNullByDefault
 public interface PrivateKey {
 
-	/**
-	 * Returns the type of this key pair.
-	 */
-	String getKeyType();
-
 	/**
 	 * Returns the encoded representation of this key.
 	 */

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

@@ -8,11 +8,6 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 @NotNullByDefault
 public interface PublicKey {
 
-	/**
-	 * Returns the type of this key pair.
-	 */
-	String getKeyType();
-
 	/**
 	 * Returns the encoded representation of this key.
 	 */

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

@@ -1,30 +0,0 @@
-package org.briarproject.bramble.api.crypto;
-
-import org.briarproject.bramble.api.Bytes;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-import static org.briarproject.bramble.api.crypto.CryptoConstants.KEY_TYPE_SIGNATURE;
-
-/**
- * Type-safe wrapper for a public key used for signing.
- */
-@Immutable
-@NotNullByDefault
-public class SignaturePrivateKey extends Bytes implements PrivateKey {
-
-	public SignaturePrivateKey(byte[] bytes) {
-		super(bytes);
-	}
-
-	@Override
-	public String getKeyType() {
-		return KEY_TYPE_SIGNATURE;
-	}
-
-	@Override
-	public byte[] getEncoded() {
-		return getBytes();
-	}
-}

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

@@ -1,35 +0,0 @@
-package org.briarproject.bramble.api.crypto;
-
-import org.briarproject.bramble.api.Bytes;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-import static org.briarproject.bramble.api.crypto.CryptoConstants.KEY_TYPE_SIGNATURE;
-import static org.briarproject.bramble.api.crypto.CryptoConstants.MAX_SIGNATURE_PUBLIC_KEY_BYTES;
-
-/**
- * Type-safe wrapper for a public key used for verifying signatures.
- */
-@Immutable
-@NotNullByDefault
-public class SignaturePublicKey extends Bytes implements PublicKey {
-
-	public SignaturePublicKey(byte[] encoded) {
-		super(encoded);
-		if (encoded.length == 0 ||
-				encoded.length > MAX_SIGNATURE_PUBLIC_KEY_BYTES) {
-			throw new IllegalArgumentException();
-		}
-	}
-
-	@Override
-	public String getKeyType() {
-		return KEY_TYPE_SIGNATURE;
-	}
-
-	@Override
-	public byte[] getEncoded() {
-		return getBytes();
-	}
-}

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

@@ -3,61 +3,27 @@ package org.briarproject.bramble.api.crypto;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
-import java.security.GeneralSecurityException;
-
 /**
  * Crypto operations for the transport security protocol - see
- * https://code.briarproject.org/briar/briar-spec/blob/master/protocols/BTP.md
+ * https://code.briarproject.org/akwizgran/briar-spec/blob/master/protocols/BTP.md
  */
 public interface TransportCrypto {
 
 	/**
-	 * Returns true if the local peer is Alice.
+	 * Derives initial transport keys for the given transport in the given
-	 */
+	 * rotation period from the given master secret.
-	boolean isAlice(PublicKey theirHandshakePublicKey,
-			KeyPair ourHandshakeKeyPair);
-
-	/**
-	 * Derives the static master key shared with a contact or pending contact.
-	 */
-	SecretKey deriveStaticMasterKey(PublicKey theirHandshakePublicKey,
-			KeyPair ourHandshakeKeyPair) throws GeneralSecurityException;
-
-	/**
-	 * Derives the handshake mode root key from the static master key. To
-	 * prevent tag reuse, separate root keys are derived for contacts and
-	 * pending contacts.
 	 *
-	 * @param pendingContact Whether the static master key is shared with a
+	 * @param alice whether the keys are for use by Alice or Bob.
-	 * pending contact or a contact
+	 * @param active whether the keys are usable for outgoing streams.
 	 */
-	SecretKey deriveHandshakeRootKey(SecretKey staticMasterKey,
+	TransportKeys deriveTransportKeys(TransportId t, SecretKey master,
-			boolean pendingContact);
+			long rotationPeriod, boolean alice, boolean active);
 
 	/**
-	 * Derives initial rotation mode transport keys for the given transport in
+	 * Rotates the given transport keys to the given rotation period. If the
-	 * the given time period from the given root key.
+	 * keys are for the given period or any later period they are not rotated.
-	 *
-	 * @param alice Whether the keys are for use by Alice or Bob
-	 * @param active Whether the keys are usable for outgoing streams
 	 */
-	TransportKeys deriveRotationKeys(TransportId t, SecretKey rootKey,
+	TransportKeys rotateTransportKeys(TransportKeys k, long rotationPeriod);
-			long timePeriod, boolean alice, boolean active);
-
-	/**
-	 * Derives handshake keys for the given transport in the given time period
-	 * from the given root key.
-	 *
-	 * @param alice Whether the keys are for use by Alice or Bob
-	 */
-	TransportKeys deriveHandshakeKeys(TransportId t, SecretKey rootKey,
-			long timePeriod, boolean alice);
-
-	/**
-	 * Updates the given transport keys to the given time period. If the keys
-	 * are for the given period or any later period they are not updated.
-	 */
-	TransportKeys updateTransportKeys(TransportKeys k, long timePeriod);
 
 	/**
 	 * Encodes the pseudo-random tag that is used to recognise a stream.

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

@@ -4,7 +4,6 @@ import org.briarproject.bramble.api.Bytes;
 import org.briarproject.bramble.api.FormatException;
 
 import java.util.Map;
-import java.util.Map.Entry;
 import java.util.TreeMap;
 
 import javax.annotation.Nullable;
@@ -24,9 +23,9 @@ public class BdfDictionary extends TreeMap<String, Object> {
 	 * );
 	 * </pre>
 	 */
-	public static BdfDictionary of(Entry<String, ?>... entries) {
+	public static BdfDictionary of(BdfEntry... entries) {
 		BdfDictionary d = new BdfDictionary();
-		for (Entry<String, ?> e : entries) d.put(e.getKey(), e.getValue());
+		for (BdfEntry e : entries) d.put(e.getKey(), e.getValue());
 		return d;
 	}
 

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

@@ -4,12 +4,12 @@ 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 javax.annotation.Nullable;
 import javax.annotation.concurrent.NotThreadSafe;
 
+import static java.util.Arrays.asList;
 import static org.briarproject.bramble.api.data.BdfDictionary.NULL_VALUE;
 
 @NotThreadSafe
@@ -22,7 +22,7 @@ public class BdfList extends ArrayList<Object> {
 	 * </pre>
 	 */
 	public static BdfList of(Object... items) {
-		return new BdfList(Arrays.asList(items));
+		return new BdfList(asList(items));
 	}
 
 	public BdfList() {
@@ -33,6 +33,7 @@ public class BdfList extends ArrayList<Object> {
 		super(items);
 	}
 
+	@SuppressWarnings("BooleanMethodIsAlwaysInverted")
 	private boolean isInRange(int index) {
 		return index >= 0 && index < size();
 	}

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

@@ -1,20 +0,0 @@
-package org.briarproject.bramble.api.db;
-
-import org.briarproject.bramble.api.event.EventExecutor;
-
-/**
- * An action that's taken when a {@link Transaction} is committed.
- */
-public interface CommitAction {
-
-	void accept(Visitor visitor);
-
-	interface Visitor {
-
-		@EventExecutor
-		void visit(EventAction a);
-
-		@EventExecutor
-		void visit(TaskAction a);
-	}
-}

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

@@ -1,27 +1,8 @@
 package org.briarproject.bramble.api.db;
 
-import org.briarproject.bramble.api.identity.Author;
-import org.briarproject.bramble.api.identity.AuthorId;
-
 /**
  * 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 {
-
-	private final AuthorId local;
-	private final Author remote;
-
-	public ContactExistsException(AuthorId local, Author remote) {
-		this.local = local;
-		this.remote = remote;
-	}
-
-	public AuthorId getLocalAuthorId() {
-		return local;
-	}
-
-	public Author getRemoteAuthor() {
-		return remote;
-	}
 }

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

@@ -2,14 +2,10 @@ package org.briarproject.bramble.api.db;
 
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.contact.PendingContact;
-import org.briarproject.bramble.api.contact.PendingContactId;
-import org.briarproject.bramble.api.crypto.PrivateKey;
-import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
-import org.briarproject.bramble.api.identity.Identity;
+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;
@@ -24,12 +20,11 @@ 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.validation.MessageState;
+import org.briarproject.bramble.api.transport.KeySet;
 import org.briarproject.bramble.api.transport.KeySetId;
-import org.briarproject.bramble.api.transport.TransportKeySet;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.util.Collection;
-import java.util.List;
 import java.util.Map;
 
 import javax.annotation.Nullable;
@@ -39,7 +34,7 @@ import javax.annotation.Nullable;
  * to other components.
  */
 @NotNullByDefault
-public interface DatabaseComponent extends TransactionManager {
+public interface DatabaseComponent {
 
 	/**
 	 * Opens the database and returns true if the database already existed.
@@ -57,12 +52,56 @@ public interface DatabaseComponent extends TransactionManager {
 	 */
 	void close() throws DbException;
 
+	/**
+	 * Starts a new transaction and returns an object representing it.
+	 * <p/>
+	 * This method acquires locks, so it must not be called while holding a
+	 * lock.
+	 *
+	 * @param readOnly true if the transaction will only be used for reading.
+	 */
+	Transaction startTransaction(boolean readOnly) throws DbException;
+
+	/**
+	 * Commits a transaction to the database.
+	 */
+	void commitTransaction(Transaction txn) throws DbException;
+
+	/**
+	 * Ends a transaction. If the transaction has not been committed,
+	 * it will be aborted. If the transaction has been committed,
+	 * any events attached to the transaction are broadcast.
+	 * The database lock will be released in either case.
+	 */
+	void endTransaction(Transaction txn);
+
+	/**
+	 * Runs the given task within a transaction.
+	 */
+	<E extends Exception> void transaction(boolean readOnly,
+			DbRunnable<E> task) throws DbException, E;
+
+	/**
+	 * Runs the given task within a transaction and returns the result of the
+	 * task.
+	 */
+	<R, E extends Exception> R transactionWithResult(boolean readOnly,
+			DbCallable<R, E> task) throws DbException, E;
+
+	/**
+	 * Runs the given task within a transaction and returns the result of the
+	 * task, which may be null.
+	 */
+	@Nullable
+	<R, E extends Exception> R transactionWithNullableResult(boolean readOnly,
+			NullableDbCallable<R, E> task) throws DbException, E;
+
 	/**
 	 * Stores a contact associated with the given local and remote pseudonyms,
 	 * and returns an ID for the contact.
 	 */
 	ContactId addContact(Transaction txn, Author remote, AuthorId local,
-			@Nullable PublicKey handshake, boolean verified) throws DbException;
+			boolean verified, boolean active) throws DbException;
 
 	/**
 	 * Stores a group.
@@ -70,21 +109,15 @@ public interface DatabaseComponent extends TransactionManager {
 	void addGroup(Transaction txn, Group g) throws DbException;
 
 	/**
-	 * Stores an identity.
+	 * Stores a local pseudonym.
 	 */
-	void addIdentity(Transaction txn, Identity i) throws DbException;
+	void addLocalAuthor(Transaction txn, LocalAuthor a) throws DbException;
 
 	/**
 	 * Stores a local message.
 	 */
 	void addLocalMessage(Transaction txn, Message m, Metadata meta,
-			boolean shared, boolean temporary) throws DbException;
+			boolean shared) throws DbException;
-
-	/**
-	 * Stores a pending contact.
-	 */
-	void addPendingContact(Transaction txn, PendingContact p, AuthorId local)
-			throws DbException;
 
 	/**
 	 * Stores a transport.
@@ -96,46 +129,25 @@ public interface DatabaseComponent extends TransactionManager {
 	 * Stores the given transport keys for the given contact and returns a
 	 * key set ID.
 	 */
-	KeySetId addTransportKeys(Transaction txn, ContactId c, TransportKeys k)
+	KeySetId addTransportKeys(Transaction txn, ContactId c,
-			throws DbException;
-
-	/**
-	 * Stores the given transport keys for the given pending contact and
-	 * returns a key set ID.
-	 */
-	KeySetId addTransportKeys(Transaction txn, PendingContactId p,
 			TransportKeys k) throws DbException;
 
 	/**
 	 * Returns true if the database contains the given contact for the given
 	 * local pseudonym.
-	 * <p/>
-	 * Read-only.
 	 */
 	boolean containsContact(Transaction txn, AuthorId remote, AuthorId local)
 			throws DbException;
 
 	/**
 	 * Returns true if the database contains the given group.
-	 * <p/>
-	 * Read-only.
 	 */
 	boolean containsGroup(Transaction txn, GroupId g) throws DbException;
 
 	/**
-	 * Returns true if the database contains an identity for the given
+	 * Returns true if the database contains the given local author.
-	 * pseudonym.
-	 * <p/>
-	 * Read-only.
 	 */
-	boolean containsIdentity(Transaction txn, AuthorId a) throws DbException;
+	boolean containsLocalAuthor(Transaction txn, AuthorId local)
-
-	/**
-	 * Returns true if the database contains the given pending contact.
-	 * <p/>
-	 * Read-only.
-	 */
-	boolean containsPendingContact(Transaction txn, PendingContactId p)
 			throws DbException;
 
 	/**
@@ -223,7 +235,7 @@ public interface DatabaseComponent extends TransactionManager {
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<ContactId> getContacts(Transaction txn, AuthorId local)
+	Collection<ContactId> getContacts(Transaction txn, AuthorId a)
 			throws DbException;
 
 	/**
@@ -258,18 +270,18 @@ public interface DatabaseComponent extends TransactionManager {
 			throws DbException;
 
 	/**
-	 * Returns the identity for the local pseudonym with the given ID.
+	 * Returns the local pseudonym with the given ID.
 	 * <p/>
 	 * Read-only.
 	 */
-	Identity getIdentity(Transaction txn, AuthorId a) throws DbException;
+	LocalAuthor getLocalAuthor(Transaction txn, AuthorId a) throws DbException;
 
 	/**
-	 * Returns the identities for all local pseudonyms.
+	 * Returns all local pseudonyms.
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<Identity> getIdentities(Transaction txn) throws DbException;
+	Collection<LocalAuthor> getLocalAuthors(Transaction txn) throws DbException;
 
 	/**
 	 * Returns the message with the given ID.
@@ -405,22 +417,6 @@ public interface DatabaseComponent extends TransactionManager {
 	 */
 	long getNextSendTime(Transaction txn, ContactId c) throws DbException;
 
-	/**
-	 * Returns the pending contact with the given ID.
-	 * <p/>
-	 * Read-only.
-	 */
-	PendingContact getPendingContact(Transaction txn, PendingContactId p)
-			throws DbException;
-
-	/**
-	 * Returns all pending contacts.
-	 * <p/>
-	 * Read-only.
-	 */
-	Collection<PendingContact> getPendingContacts(Transaction txn)
-			throws DbException;
-
 	/**
 	 * Returns all settings in the given namespace.
 	 * <p/>
@@ -428,19 +424,12 @@ public interface DatabaseComponent extends TransactionManager {
 	 */
 	Settings getSettings(Transaction txn, String namespace) throws DbException;
 
-	/**
-	 * Returns the versions of the sync protocol supported by the given contact.
-	 * <p/>
-	 * Read-only.
-	 */
-	List<Byte> getSyncVersions(Transaction txn, ContactId c) throws DbException;
-
 	/**
 	 * Returns all transport keys for the given transport.
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<TransportKeySet> getTransportKeys(Transaction txn, TransportId t)
+	Collection<KeySet> getTransportKeys(Transaction txn, TransportId t)
 			throws DbException;
 
 	/**
@@ -503,27 +492,15 @@ public interface DatabaseComponent extends TransactionManager {
 	void removeGroup(Transaction txn, Group g) throws DbException;
 
 	/**
-	 * Removes an identity (and all associated state) from the database.
+	 * Removes a local pseudonym (and all associated state) from the database.
 	 */
-	void removeIdentity(Transaction txn, AuthorId a) throws DbException;
+	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 pending contact (and all associated state) from the database.
-	 */
-	void removePendingContact(Transaction txn, PendingContactId p)
-			throws DbException;
-
-	/**
-	 * Removes all temporary messages (and all associated state) from the
-	 * database.
-	 */
-	void removeTemporaryMessages(Transaction txn) throws DbException;
-
 	/**
 	 * Removes a transport (and all associated state) from the database.
 	 */
@@ -540,6 +517,12 @@ public interface DatabaseComponent extends TransactionManager {
 	 */
 	void setContactVerified(Transaction txn, ContactId c) throws DbException;
 
+	/**
+	 * Marks the given contact as active or inactive.
+	 */
+	void setContactActive(Transaction txn, ContactId c, boolean active)
+			throws DbException;
+
 	/**
 	 * Sets an alias name for the contact or unsets it if alias is null.
 	 */
@@ -552,11 +535,6 @@ public interface DatabaseComponent extends TransactionManager {
 	void setGroupVisibility(Transaction txn, ContactId c, GroupId g,
 			Visibility v) throws DbException;
 
-	/**
-	 * Marks the given message as permanent, i.e. not temporary.
-	 */
-	void setMessagePermanent(Transaction txn, MessageId m) throws DbException;
-
 	/**
 	 * Marks the given message as shared.
 	 */
@@ -575,23 +553,11 @@ public interface DatabaseComponent extends TransactionManager {
 			Collection<MessageId> dependencies) throws DbException;
 
 	/**
-	 * Sets the handshake key pair for the identity with the given ID.
+	 * Sets the reordering window for the given key set and transport in the
-	 */
+	 * given rotation period.
-	void setHandshakeKeyPair(Transaction txn, AuthorId local,
-			PublicKey publicKey, PrivateKey privateKey) throws DbException;
-
-	/**
-	 * Sets the reordering window for the given transport keys in the given
-	 * time period.
 	 */
 	void setReorderingWindow(Transaction txn, KeySetId k, TransportId t,
-			long timePeriod, long base, byte[] bitmap) throws DbException;
+			long rotationPeriod, long base, byte[] bitmap) throws DbException;
-
-	/**
-	 * Sets the versions of the sync protocol supported by the given contact.
-	 */
-	void setSyncVersions(Transaction txn, ContactId c, List<Byte> supported)
-			throws DbException;
 
 	/**
 	 * Marks the given transport keys as usable for outgoing streams.
@@ -602,6 +568,6 @@ public interface DatabaseComponent extends TransactionManager {
 	/**
 	 * Stores the given transport keys, deleting any keys they have replaced.
 	 */
-	void updateTransportKeys(Transaction txn, Collection<TransportKeySet> keys)
+	void updateTransportKeys(Transaction txn, Collection<KeySet> keys)
 			throws DbException;
 }

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

@@ -1,29 +1,15 @@
 package org.briarproject.bramble.api.db;
 
-import org.briarproject.bramble.api.crypto.KeyStrengthener;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.io.File;
 
-import javax.annotation.Nullable;
-
 @NotNullByDefault
 public interface DatabaseConfig {
 
-	/**
-	 * Returns the directory where the database stores its data.
-	 */
 	File getDatabaseDirectory();
 
-	/**
-	 * Returns the directory where the encrypted database key is stored.
-	 */
 	File getDatabaseKeyDirectory();
 
-	/**
+	long getMaxSize();
-	 * Returns a {@link KeyStrengthener} for strengthening the encryption of
-	 * the database key, or null if no strengthener should be used.
-	 */
-	@Nullable
-	KeyStrengthener getKeyStrengthener();
 }

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

@@ -1,24 +0,0 @@
-package org.briarproject.bramble.api.db;
-
-import org.briarproject.bramble.api.event.Event;
-
-/**
- * A {@link CommitAction} that broadcasts an event.
- */
-public class EventAction implements CommitAction {
-
-	private final Event event;
-
-	EventAction(Event event) {
-		this.event = event;
-	}
-
-	public Event getEvent() {
-		return event;
-	}
-
-	@Override
-	public void accept(Visitor visitor) {
-		visitor.visit(this);
-	}
-}

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

@@ -1,9 +1,9 @@
 package org.briarproject.bramble.api.db;
 
 /**
- * Thrown when a database operation is attempted for an identity that is not in
+ * Thrown when a database operation is attempted for a pseudonym that is not in
  * the database. This exception may occur due to concurrent updates and does
  * not indicate a database error.
  */
-public class NoSuchIdentityException extends DbException {
+public class NoSuchLocalAuthorException extends DbException {
 }

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

@@ -1,9 +0,0 @@
-package org.briarproject.bramble.api.db;
-
-/**
- * Thrown when a database operation is attempted for a pending contact that is
- * not in the database. This exception may occur due to concurrent updates and
- * does not indicate a database error.
- */
-public class NoSuchPendingContactException extends DbException {
-}

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

@@ -1,21 +0,0 @@
-package org.briarproject.bramble.api.db;
-
-import org.briarproject.bramble.api.contact.PendingContact;
-
-/**
- * Thrown when a duplicate pending contact is added to the database. This
- * exception may occur due to concurrent updates and does not indicate a
- * database error.
- */
-public class PendingContactExistsException extends DbException {
-
-	private final PendingContact pendingContact;
-
-	public PendingContactExistsException(PendingContact pendingContact) {
-		this.pendingContact = pendingContact;
-	}
-
-	public PendingContact getPendingContact() {
-		return pendingContact;
-	}
-}

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

@@ -1,24 +0,0 @@
-package org.briarproject.bramble.api.db;
-
-import org.briarproject.bramble.api.event.EventExecutor;
-
-/**
- * A {@link CommitAction} that submits a task to the {@link EventExecutor}.
- */
-public class TaskAction implements CommitAction {
-
-	private final Runnable task;
-
-	TaskAction(Runnable task) {
-		this.task = task;
-	}
-
-	public Runnable getTask() {
-		return task;
-	}
-
-	@Override
-	public void accept(Visitor visitor) {
-		visitor.visit(this);
-	}
-}

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

@@ -1,7 +1,6 @@
 package org.briarproject.bramble.api.db;
 
 import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.event.EventExecutor;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -19,7 +18,7 @@ public class Transaction {
 	private final Object txn;
 	private final boolean readOnly;
 
-	private List<CommitAction> actions = null;
+	private List<Event> events = null;
 	private boolean committed = false;
 
 	public Transaction(Object txn, boolean readOnly) {
@@ -44,27 +43,19 @@ public class Transaction {
 
 	/**
 	 * Attaches an event to be broadcast when the transaction has been
-	 * committed. The event will be broadcast on the {@link EventExecutor}.
+	 * committed.
 	 */
 	public void attach(Event e) {
-		if (actions == null) actions = new ArrayList<>();
+		if (events == null) events = new ArrayList<>();
-		actions.add(new EventAction(e));
+		events.add(e);
 	}
 
 	/**
-	 * Attaches a task to be executed when the transaction has been
+	 * Returns any events attached to the transaction.
-	 * committed. The task will be run on the {@link EventExecutor}.
 	 */
-	public void attach(Runnable r) {
+	public List<Event> getEvents() {
-		if (actions == null) actions = new ArrayList<>();
+		if (events == null) return emptyList();
-		actions.add(new TaskAction(r));
+		return events;
-	}
-
-	/**
-	 * Returns any actions attached to the transaction.
-	 */
-	public List<CommitAction> getActions() {
-		return actions == null ? emptyList() : actions;
 	}
 
 	/**

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

@@ -1,54 +0,0 @@
-package org.briarproject.bramble.api.db;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.Nullable;
-
-@NotNullByDefault
-public interface TransactionManager {
-
-	/**
-	 * Starts a new transaction and returns an object representing it.
-	 * <p/>
-	 * This method acquires locks, so it must not be called while holding a
-	 * lock.
-	 *
-	 * @param readOnly true if the transaction will only be used for reading.
-	 */
-	Transaction startTransaction(boolean readOnly) throws DbException;
-
-	/**
-	 * Commits a transaction to the database.
-	 */
-	void commitTransaction(Transaction txn) throws DbException;
-
-	/**
-	 * Ends a transaction. If the transaction has not been committed,
-	 * it will be aborted. If the transaction has been committed,
-	 * any events attached to the transaction are broadcast.
-	 * The database lock will be released in either case.
-	 */
-	void endTransaction(Transaction txn);
-
-	/**
-	 * Runs the given task within a transaction.
-	 */
-	<E extends Exception> void transaction(boolean readOnly,
-			DbRunnable<E> task) throws DbException, E;
-
-	/**
-	 * Runs the given task within a transaction and returns the result of the
-	 * task.
-	 */
-	<R, E extends Exception> R transactionWithResult(boolean readOnly,
-			DbCallable<R, E> task) throws DbException, E;
-
-	/**
-	 * Runs the given task within a transaction and returns the result of the
-	 * task, which may be null.
-	 */
-	@Nullable
-	<R, E extends Exception> R transactionWithNullableResult(boolean readOnly,
-			NullableDbCallable<R, E> task) throws DbException, E;
-
-}

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

@@ -16,8 +16,7 @@ public interface EventBus {
 	void removeListener(EventListener l);
 
 	/**
-	 * Asynchronously notifies all listeners of an event. Listeners are
+	 * Notifies all listeners of an event.
-	 * notified on the {@link EventExecutor}.
 	 */
 	void broadcast(Event e);
 }

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

@@ -1,26 +0,0 @@
-package org.briarproject.bramble.api.event;
-
-import java.lang.annotation.Retention;
-import java.lang.annotation.Target;
-
-import javax.inject.Qualifier;
-
-import static java.lang.annotation.ElementType.FIELD;
-import static java.lang.annotation.ElementType.METHOD;
-import static java.lang.annotation.ElementType.PARAMETER;
-import static java.lang.annotation.RetentionPolicy.RUNTIME;
-
-/**
- * Annotation for injecting the executor for broadcasting events and running
- * tasks that need to run in a defined order with respect to events. Also used
- * for annotating methods that should run on the event executor.
- * <p>
- * The contract of this executor is that tasks are run in the order they're
- * submitted, tasks are not run concurrently, and submitting a task will never
- * block. Tasks must not block. Tasks submitted during shutdown are discarded.
- */
-@Qualifier
-@Target({FIELD, METHOD, PARAMETER})
-@Retention(RUNTIME)
-public @interface EventExecutor {
-}

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

@@ -12,6 +12,5 @@ public interface EventListener {
 	 * Called when an event is broadcast. Implementations of this method must
 	 * not block.
 	 */
-	@EventExecutor
 	void eventOccurred(Event e);
 }

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

@@ -1,13 +1,12 @@
 package org.briarproject.bramble.api.identity;
 
 import org.briarproject.bramble.api.Nameable;
-import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import javax.annotation.concurrent.Immutable;
 
-import static org.briarproject.bramble.api.crypto.CryptoConstants.KEY_TYPE_SIGNATURE;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
 import static org.briarproject.bramble.util.StringUtils.toUtf8;
 
 /**
@@ -25,14 +24,14 @@ public class Author implements Nameable {
 	private final AuthorId id;
 	private final int formatVersion;
 	private final String name;
-	private final PublicKey publicKey;
+	private final byte[] publicKey;
 
 	public Author(AuthorId id, int formatVersion, String name,
-			PublicKey publicKey) {
+			byte[] publicKey) {
 		int nameLength = toUtf8(name).length;
 		if (nameLength == 0 || nameLength > MAX_AUTHOR_NAME_LENGTH)
 			throw new IllegalArgumentException();
-		if (!publicKey.getKeyType().equals(KEY_TYPE_SIGNATURE))
+		if (publicKey.length == 0 || publicKey.length > MAX_PUBLIC_KEY_LENGTH)
 			throw new IllegalArgumentException();
 		this.id = id;
 		this.formatVersion = formatVersion;
@@ -64,7 +63,7 @@ public class Author implements Nameable {
 	/**
 	 * Returns the public key used to verify the pseudonym's signatures.
 	 */
-	public PublicKey getPublicKey() {
+	public byte[] getPublicKey() {
 		return publicKey;
 	}
 

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

@@ -1,6 +1,5 @@
 package org.briarproject.bramble.api.identity;
 
-import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 @NotNullByDefault
@@ -10,16 +9,23 @@ public interface AuthorFactory {
 	 * Creates an author with the current format version and the given name and
 	 * public key.
 	 */
-	Author createAuthor(String name, PublicKey publicKey);
+	Author createAuthor(String name, byte[] publicKey);
 
 	/**
 	 * Creates an author with the given format version, name and public key.
 	 */
-	Author createAuthor(int formatVersion, String name, PublicKey publicKey);
+	Author createAuthor(int formatVersion, String name, byte[] publicKey);
 
 	/**
 	 * Creates a local author with the current format version and the given
-	 * name.
+	 * name and keys.
 	 */
-	LocalAuthor createLocalAuthor(String name);
+	LocalAuthor createLocalAuthor(String name, byte[] publicKey,
+			byte[] privateKey);
+
+	/**
+	 * Creates a local author with the given format version, name and keys.
+	 */
+	LocalAuthor createLocalAuthor(int formatVersion, String name,
+			byte[] publicKey, byte[] privateKey);
 }

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

@@ -1,88 +0,0 @@
-package org.briarproject.bramble.api.identity;
-
-import org.briarproject.bramble.api.crypto.PrivateKey;
-import org.briarproject.bramble.api.crypto.PublicKey;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.Nullable;
-import javax.annotation.concurrent.Immutable;
-
-import static org.briarproject.bramble.api.crypto.CryptoConstants.KEY_TYPE_AGREEMENT;
-
-@Immutable
-@NotNullByDefault
-public class Identity {
-
-	private final LocalAuthor localAuthor;
-	@Nullable
-	private final PublicKey handshakePublicKey;
-	@Nullable
-	private final PrivateKey handshakePrivateKey;
-	private final long created;
-
-	public Identity(LocalAuthor localAuthor,
-			@Nullable PublicKey handshakePublicKey,
-			@Nullable PrivateKey handshakePrivateKey, long created) {
-		if (handshakePublicKey != null) {
-			if (handshakePrivateKey == null)
-				throw new IllegalArgumentException();
-			if (!handshakePublicKey.getKeyType().equals(KEY_TYPE_AGREEMENT))
-				throw new IllegalArgumentException();
-		}
-		if (handshakePrivateKey != null) {
-			if (handshakePublicKey == null)
-				throw new IllegalArgumentException();
-			if (!handshakePrivateKey.getKeyType().equals(KEY_TYPE_AGREEMENT))
-				throw new IllegalArgumentException();
-		}
-		this.localAuthor = localAuthor;
-		this.handshakePublicKey = handshakePublicKey;
-		this.handshakePrivateKey = handshakePrivateKey;
-		this.created = created;
-	}
-
-	/**
-	 * Returns the ID of the user's pseudonym.
-	 */
-	public AuthorId getId() {
-		return localAuthor.getId();
-	}
-
-	/**
-	 * Returns the user's pseudonym.
-	 */
-	public LocalAuthor getLocalAuthor() {
-		return localAuthor;
-	}
-
-	/**
-	 * Returns true if the identity has a handshake key pair.
-	 */
-	public boolean hasHandshakeKeyPair() {
-		return handshakePublicKey != null && handshakePrivateKey != null;
-	}
-
-	/**
-	 * Returns the public key used for handshaking, or null if no key exists.
-	 */
-	@Nullable
-	public PublicKey getHandshakePublicKey() {
-		return handshakePublicKey;
-	}
-
-	/**
-	 * Returns the private key used for handshaking, or null if no key exists.
-	 */
-	@Nullable
-	public PrivateKey getHandshakePrivateKey() {
-		return handshakePrivateKey;
-	}
-
-	/**
-	 * Returns the time the identity was created, in milliseconds since the
-	 * Unix epoch.
-	 */
-	public long getTimeCreated() {
-		return created;
-	}
-}

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

@@ -1,30 +1,30 @@
 package org.briarproject.bramble.api.identity;
 
 import org.briarproject.bramble.api.crypto.CryptoExecutor;
-import org.briarproject.bramble.api.crypto.KeyPair;
-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.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 @NotNullByDefault
 public interface IdentityManager {
 
 	/**
-	 * Creates an identity with the given name. The identity includes a
+	 * Creates a local identity with the given name.
-	 * handshake key pair.
 	 */
 	@CryptoExecutor
-	Identity createIdentity(String name);
+	LocalAuthor createLocalAuthor(String name);
 
 	/**
-	 * Registers the given identity with the manager. This method should be
+	 * Registers the given local identity with the manager. The identity is
-	 * called before {@link LifecycleManager#startServices(SecretKey)}. The
+	 * not stored until {@link #storeLocalAuthor()} is called.
-	 * identity is stored when {@link LifecycleManager#startServices(SecretKey)}
-	 * is called. The identity must include a handshake key pair.
 	 */
-	void registerIdentity(Identity i);
+	void registerLocalAuthor(LocalAuthor a);
+
+	/**
+	 * Stores the local identity registered with
+	 * {@link #registerLocalAuthor(LocalAuthor)}, if any.
+	 */
+	void storeLocalAuthor() throws DbException;
 
 	/**
 	 * Returns the cached local identity or loads it from the database.
@@ -33,15 +33,7 @@ public interface IdentityManager {
 
 	/**
 	 * Returns the cached local identity or loads it from the database.
-	 * <p/>
-	 * Read-only.
 	 */
 	LocalAuthor getLocalAuthor(Transaction txn) throws DbException;
 
-	/**
-	 * Returns the cached handshake keys or loads them from the database.
-	 * <p/>
-	 * Read-only.
-	 */
-	KeyPair getHandshakeKeys(Transaction txn) throws DbException;
 }

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

@@ -1,13 +1,9 @@
 package org.briarproject.bramble.api.identity;
 
-import org.briarproject.bramble.api.crypto.PrivateKey;
-import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import javax.annotation.concurrent.Immutable;
 
-import static org.briarproject.bramble.api.crypto.CryptoConstants.KEY_TYPE_SIGNATURE;
-
 /**
  * A pseudonym for the local user.
  */
@@ -15,20 +11,28 @@ import static org.briarproject.bramble.api.crypto.CryptoConstants.KEY_TYPE_SIGNA
 @NotNullByDefault
 public class LocalAuthor extends Author {
 
-	private final PrivateKey privateKey;
+	private final byte[] privateKey;
+	private final long created;
 
 	public LocalAuthor(AuthorId id, int formatVersion, String name,
-			PublicKey publicKey, PrivateKey privateKey) {
+			byte[] publicKey, byte[] privateKey, long created) {
 		super(id, formatVersion, name, publicKey);
-		if (!privateKey.getKeyType().equals(KEY_TYPE_SIGNATURE))
-			throw new IllegalArgumentException();
 		this.privateKey = privateKey;
+		this.created = created;
 	}
 
 	/**
 	 * Returns the private key used to generate the pseudonym's signatures.
 	 */
-	public PrivateKey getPrivateKey() {
+	public byte[] getPrivateKey() {
 		return privateKey;
 	}
+
+	/**
+	 * Returns the time the pseudonym was created, in milliseconds since the
+	 * Unix epoch.
+	 */
+	public long getTimeCreated() {
+		return created;
+	}
 }

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

@@ -7,15 +7,15 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import javax.annotation.concurrent.Immutable;
 
 /**
- * An event that is broadcast when an identity is added.
+ * An event that is broadcast when a local pseudonym is added.
  */
 @Immutable
 @NotNullByDefault
-public class IdentityAddedEvent extends Event {
+public class LocalAuthorAddedEvent extends Event {
 
 	private final AuthorId authorId;
 
-	public IdentityAddedEvent(AuthorId authorId) {
+	public LocalAuthorAddedEvent(AuthorId authorId) {
 		this.authorId = authorId;
 	}
 

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

@@ -7,15 +7,15 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import javax.annotation.concurrent.Immutable;
 
 /**
- * An event that is broadcast when an identity is removed.
+ * An event that is broadcast when a local pseudonym is removed.
  */
 @Immutable
 @NotNullByDefault
-public class IdentityRemovedEvent extends Event {
+public class LocalAuthorRemovedEvent extends Event {
 
 	private final AuthorId authorId;
 
-	public IdentityRemovedEvent(AuthorId authorId) {
+	public LocalAuthorRemovedEvent(AuthorId authorId) {
 		this.authorId = authorId;
 	}
 

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

@@ -40,8 +40,8 @@ public interface KeyAgreementConstants {
 			"org.briarproject.bramble.keyagreement/SHARED_SECRET";
 
 	/**
-	 * Label for deriving the master key.
+	 * Label for deriving the master secret.
 	 */
-	String MASTER_KEY_LABEL =
+	String MASTER_SECRET_LABEL =
 			"org.briarproject.bramble.keyagreement/MASTER_SECRET";
 }

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

@@ -5,7 +5,7 @@ import org.briarproject.bramble.api.data.BdfList;
 import java.io.IOException;
 
 /**
- * Accepts key agreement connections over a given transport.
+ * An class for managing a particular key agreement listener.
  */
 public abstract class KeyAgreementListener {
 

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

@@ -0,0 +1,20 @@
+package org.briarproject.bramble.api.keyagreement;
+
+import java.io.IOException;
+
+/**
+ * Thrown when a QR code that has been scanned uses a protocol version that is
+ * not supported.
+ */
+public class UnsupportedVersionException extends IOException {
+
+	private final boolean tooOld;
+
+	public UnsupportedVersionException(boolean tooOld) {
+		this.tooOld = tooOld;
+	}
+
+	public boolean isTooOld() {
+		return tooOld;
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/lifecycle/LifecycleManager.java

@@ -2,16 +2,16 @@ package org.briarproject.bramble.api.lifecycle;
 
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.DatabaseComponent;
-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.Client;
 
 import java.util.concurrent.ExecutorService;
 
 /**
- * Manages the lifecycle of the app: opening and closing the
+ * Manages the lifecycle of the app, starting {@link Client Clients}, starting
- * {@link DatabaseComponent} starting and stopping {@link Service Services},
+ * and stopping {@link Service Services}, shutting down
- * and shutting down {@link ExecutorService ExecutorServices}.
+ * {@link ExecutorService ExecutorServices}, and opening and closing the
+ * {@link DatabaseComponent}.
  */
 @NotNullByDefault
 public interface LifecycleManager {
@@ -42,19 +42,18 @@ public interface LifecycleManager {
 		}
 	}
 
-	/**
-	 * Registers a hook to be called after the database is opened and before
-	 * {@link Service services} are started. This method should be called
-	 * before {@link #startServices(SecretKey)}.
-	 */
-	void registerOpenDatabaseHook(OpenDatabaseHook hook);
-
 	/**
 	 * Registers a {@link Service} to be started and stopped. This method
 	 * should be called before {@link #startServices(SecretKey)}.
 	 */
 	void registerService(Service s);
 
+	/**
+	 * Registers a {@link Client} to be started. This method should be called
+	 * before {@link #startServices(SecretKey)}.
+	 */
+	void registerClient(Client c);
+
 	/**
 	 * Registers an {@link ExecutorService} to be shut down. This method
 	 * should be called before {@link #startServices(SecretKey)}.
@@ -63,7 +62,7 @@ public interface LifecycleManager {
 
 	/**
 	 * Opens the {@link DatabaseComponent} using the given key and starts any
-	 * registered {@link Service Services}.
+	 * registered {@link Client Clients} and {@link Service Services}.
 	 */
 	StartResult startServices(SecretKey dbKey);
 
@@ -81,7 +80,8 @@ public interface LifecycleManager {
 
 	/**
 	 * Waits for the {@link DatabaseComponent} to be opened and all registered
-	 * {@link Service Services} to start before returning.
+	 * {@link Client Clients} and {@link Service Services} to start before
+	 * returning.
 	 */
 	void waitForStartup() throws InterruptedException;
 
@@ -97,13 +97,4 @@ public interface LifecycleManager {
 	 */
 	LifecycleState getLifecycleState();
 
-	interface OpenDatabaseHook {
-		/**
-		 * Called when the database is being opened, before
-		 * {@link #waitForDatabase()} returns.
-		 *
-		 * @param txn A read-write transaction
-		 */
-		void onDatabaseOpened(Transaction txn) throws DbException;
-	}
 }

bramble-api/src/main/java/org/briarproject/bramble/api/nullsafety/NullSafety.java

@@ -6,27 +6,10 @@ import javax.annotation.Nullable;
 public class NullSafety {
 
 	/**
-	 * Stand-in for {@code Objects.requireNonNull()}.
+	 * Stand-in for `Objects.requireNonNull()`.
 	 */
 	public static <T> T requireNonNull(@Nullable T t) {
 		if (t == null) throw new NullPointerException();
 		return t;
 	}
-
-	/**
-	 * Checks that exactly one of the arguments is null.
-	 *
-	 * @throws AssertionError If both or neither of the arguments are null
-	 */
-	public static void requireExactlyOneNull(@Nullable Object a,
-			@Nullable Object b) {
-		if ((a == null) == (b == null)) throw new AssertionError();
-	}
-
-	/**
-	 * Checks that the argument is null.
-	 */
-	public static void requireNull(@Nullable Object o) {
-		if (o != null) throw new AssertionError();
-	}
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/ConnectionHandler.java

@@ -1,28 +0,0 @@
-package org.briarproject.bramble.api.plugin;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
-
-/**
- * An interface for handling connections created by transport plugins.
- */
-@NotNullByDefault
-public interface ConnectionHandler {
-
-	/**
-	 * Handles a connection created by a {@link DuplexPlugin}.
-	 */
-	void handleConnection(DuplexTransportConnection c);
-
-	/**
-	 * Handles a reader created by a {@link SimplexPlugin}.
-	 */
-	void handleReader(TransportConnectionReader r);
-
-	/**
-	 * Handles a writer created by a {@link SimplexPlugin}.
-	 */
-	void handleWriter(TransportConnectionWriter w);
-}

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/ConnectionManager.java

@@ -1,46 +1,17 @@
 package org.briarproject.bramble.api.plugin;
 
 import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.contact.PendingContactId;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 
-@NotNullByDefault
 public interface ConnectionManager {
 
-	/**
-	 * Manages an incoming connection from a contact over a simplex transport.
-	 */
 	void manageIncomingConnection(TransportId t, TransportConnectionReader r);
 
-	/**
-	 * Manages an incoming connection from a contact over a duplex transport.
-	 */
 	void manageIncomingConnection(TransportId t, DuplexTransportConnection d);
 
-	/**
-	 * Manages an incoming handshake connection from a pending contact over a
-	 * duplex transport.
-	 */
-	void manageIncomingConnection(PendingContactId p, TransportId t,
-			DuplexTransportConnection d);
-
-	/**
-	 * Manages an outgoing connection to a contact over a simplex transport.
-	 */
 	void manageOutgoingConnection(ContactId c, TransportId t,
 			TransportConnectionWriter w);
 
-	/**
-	 * Manages an outgoing connection to a contact over a duplex transport.
-	 */
 	void manageOutgoingConnection(ContactId c, TransportId t,
 			DuplexTransportConnection d);
-
-	/**
-	 * Manages an outgoing handshake connection to a pending contact over a
-	 * duplex transport.
-	 */
-	void manageOutgoingConnection(PendingContactId p, TransportId t,
-			DuplexTransportConnection d);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/ConnectionRegistry.java

@@ -1,14 +1,7 @@
 package org.briarproject.bramble.api.plugin;
 
 import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.contact.PendingContactId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
-import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
-import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
-import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
-import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionClosedEvent;
-import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionOpenedEvent;
 
 import java.util.Collection;
 
@@ -18,50 +11,13 @@ import java.util.Collection;
 @NotNullByDefault
 public interface ConnectionRegistry {
 
-	/**
-	 * Registers a connection with the given contact over the given transport.
-	 * Broadcasts {@link ConnectionOpenedEvent}. Also broadcasts
-	 * {@link ContactConnectedEvent} if this is the only connection with the
-	 * contact.
-	 */
 	void registerConnection(ContactId c, TransportId t, boolean incoming);
 
-	/**
-	 * Unregisters a connection with the given contact over the given transport.
-	 * Broadcasts {@link ConnectionClosedEvent}. Also broadcasts
-	 * {@link ContactDisconnectedEvent} if this is the only connection with
-	 * the contact.
-	 */
 	void unregisterConnection(ContactId c, TransportId t, boolean incoming);
 
-	/**
-	 * Returns any contacts that are connected via the given transport.
-	 */
 	Collection<ContactId> getConnectedContacts(TransportId t);
 
-	/**
-	 * Returns true if the given contact is connected via the given transport.
-	 */
 	boolean isConnected(ContactId c, TransportId t);
 
-	/**
-	 * Returns true if the given contact is connected via any transport.
-	 */
 	boolean isConnected(ContactId c);
-
-	/**
-	 * Registers a connection with the given pending contact. Broadcasts
-	 * {@link RendezvousConnectionOpenedEvent} if this is the only connection
-	 * with the pending contact.
-	 *
-	 * @return True if this is the only connection with the pending contact,
-	 * false if it is redundant and should be closed
-	 */
-	boolean registerConnection(PendingContactId p);
-
-	/**
-	 * Unregisters a connection with the given pending contact. Broadcasts
-	 * {@link RendezvousConnectionClosedEvent}.
-	 */
-	void unregisterConnection(PendingContactId p, boolean success);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/Plugin.java

@@ -1,10 +1,10 @@
 package org.briarproject.bramble.api.plugin;
 
-import org.briarproject.bramble.api.Pair;
+import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.properties.TransportProperties;
 
-import java.util.Collection;
+import java.util.Map;
 
 @NotNullByDefault
 public interface Plugin {
@@ -51,9 +51,8 @@ public interface Plugin {
 	int getPollingInterval();
 
 	/**
-	 * Attempts to create connections using the given transport properties,
+	 * Attempts to establish connections to the given contacts, passing any
-	 * passing any created connections to the corresponding handlers.
+	 * created connections to the callback.
 	 */
-	void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
+	void poll(Map<ContactId, TransportProperties> contacts);
-			properties);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/PluginCallback.java

@@ -9,7 +9,7 @@ import org.briarproject.bramble.api.settings.Settings;
  * the application.
  */
 @NotNullByDefault
-public interface PluginCallback extends ConnectionHandler {
+public interface PluginCallback {
 
 	/**
 	 * Returns the plugin's settings

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/PluginManager.java

@@ -36,9 +36,4 @@ public interface PluginManager {
 	 * Returns any duplex plugins that support key agreement.
 	 */
 	Collection<DuplexPlugin> getKeyAgreementPlugins();
-
-	/**
-	 * Returns any duplex plugins that support rendezvous.
-	 */
-	Collection<DuplexPlugin> getRendezvousPlugins();
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/TransportId.java

@@ -1,6 +1,6 @@
 package org.briarproject.bramble.api.plugin;
 
-import org.briarproject.bramble.util.StringUtils;
+import static org.briarproject.bramble.util.StringUtils.toUtf8;
 
 /**
  * Type-safe wrapper for a namespaced string that uniquely identifies a
@@ -11,12 +11,12 @@ public class TransportId {
 	/**
 	 * The maximum length of a transport identifier in UTF-8 bytes.
 	 */
-	public static int MAX_TRANSPORT_ID_LENGTH = 100;
+	public static final int MAX_TRANSPORT_ID_LENGTH = 100;
 
 	private final String id;
 
 	public TransportId(String id) {
-		int length = StringUtils.toUtf8(id).length;
+		int length = toUtf8(id).length;
 		if (length == 0 || length > MAX_TRANSPORT_ID_LENGTH)
 			throw new IllegalArgumentException();
 		this.id = id;

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

@@ -3,11 +3,8 @@ package org.briarproject.bramble.api.plugin.duplex;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.ConnectionHandler;
 import org.briarproject.bramble.api.plugin.Plugin;
 import org.briarproject.bramble.api.properties.TransportProperties;
-import org.briarproject.bramble.api.rendezvous.KeyMaterialSource;
-import org.briarproject.bramble.api.rendezvous.RendezvousEndpoint;
 
 import javax.annotation.Nullable;
 
@@ -43,19 +40,4 @@ public interface DuplexPlugin extends Plugin {
 	@Nullable
 	DuplexTransportConnection createKeyAgreementConnection(
 			byte[] remoteCommitment, BdfList descriptor);
-
-	/**
-	 * Returns true if the plugin supports rendezvous connections.
-	 */
-	boolean supportsRendezvous();
-
-	/**
-	 * Creates and returns an endpoint that uses the given key material to
-	 * rendezvous with a pending contact, and the given connection handler to
-	 * handle incoming connections. Returns null if an endpoint cannot be
-	 * created.
-	 */
-	@Nullable
-	RendezvousEndpoint createRendezvousEndpoint(KeyMaterialSource k,
-			boolean alice, ConnectionHandler incoming);
 }

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

@@ -0,0 +1,17 @@
+package org.briarproject.bramble.api.plugin.duplex;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.PluginCallback;
+
+/**
+ * An interface through which a duplex plugin interacts with the rest of the
+ * application.
+ */
+@NotNullByDefault
+public interface DuplexPluginCallback extends PluginCallback {
+
+	void incomingConnectionCreated(DuplexTransportConnection d);
+
+	void outgoingConnectionCreated(ContactId c, DuplexTransportConnection d);
+}

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

@@ -1,7 +1,6 @@
 package org.briarproject.bramble.api.plugin.duplex;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.TransportId;
 
 import javax.annotation.Nullable;
@@ -26,5 +25,5 @@ public interface DuplexPluginFactory {
 	 * Creates and returns a plugin, or null if no plugin can be created.
 	 */
 	@Nullable
-	DuplexPlugin createPlugin(PluginCallback callback);
+	DuplexPlugin createPlugin(DuplexPluginCallback callback);
 }