Remove local author from contacts.

Bump schema version to match migrations

See merge request briar/briar!1084

bramble-android/build.gradle

@@ -11,8 +11,8 @@ android {
 	defaultConfig {
 		minSdkVersion 14
 		targetSdkVersion 26
-		versionCode 10105
-		versionName "1.1.5"
+		versionCode 10106
+		versionName "1.1.6"
 		consumerProguardFiles 'proguard-rules.txt'
 
 		testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
@@ -30,8 +30,8 @@ configurations {
 
 dependencies {
 	implementation project(path: ':bramble-core', configuration: 'default')
-	tor 'org.briarproject:tor-android:0.3.4.8@zip'
-	tor 'org.briarproject:obfs4proxy-android:0.0.7@zip'
+	tor 'org.briarproject:tor-android:0.3.5.8@zip'
+	tor 'org.briarproject:obfs4proxy-android:0.0.9@zip'
 
 	annotationProcessor 'com.google.dagger:dagger-compiler:2.19'
 

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

@@ -12,11 +12,15 @@ import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.util.IoUtils;
 
 import java.io.File;
+import java.util.HashSet;
+import java.util.Set;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 
+import static android.os.Build.VERSION.SDK_INT;
+
 class AndroidAccountManager extends AccountManagerImpl
 		implements AccountManager {
 
@@ -89,20 +93,42 @@ 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[] children = dataDir.listFiles();
-		if (children == null) {
+		@Nullable
+		File[] fileArray = dataDir.listFiles();
+		if (fileArray == null) {
 			LOG.warning("Could not list files in app data dir");
 		} else {
-			for (File child : children) {
-				String name = child.getName();
+			for (File file : fileArray) {
+				String name = file.getName();
 				if (!name.equals("lib") && !name.equals("shared_prefs")) {
-					IoUtils.deleteFileOrDir(child);
+					files.add(file);
 				}
 			}
 		}
+		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) {
+			IoUtils.deleteFileOrDir(file);
+		}
 		// Recreate the cache dir as some OpenGL drivers expect it to exist
-		if (!new File(dataDir, "cache").mkdir())
+		if (!new File(dataDir, "cache").mkdirs())
 			LOG.warning("Could not recreate cache dir");
 	}
+
+	private void addIfNotNull(Set<File> files, @Nullable File file) {
+		if (file != null) files.add(file);
+	}
 }

bramble-android/src/main/java/org/briarproject/bramble/battery/AndroidBatteryManager.java

@@ -19,9 +19,7 @@ import javax.inject.Inject;
 import static android.content.Intent.ACTION_BATTERY_CHANGED;
 import static android.content.Intent.ACTION_POWER_CONNECTED;
 import static android.content.Intent.ACTION_POWER_DISCONNECTED;
-import static android.os.BatteryManager.BATTERY_STATUS_CHARGING;
-import static android.os.BatteryManager.BATTERY_STATUS_FULL;
-import static android.os.BatteryManager.EXTRA_STATUS;
+import static android.os.BatteryManager.EXTRA_PLUGGED;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Logger.getLogger;
 
@@ -48,9 +46,8 @@ class AndroidBatteryManager implements BatteryManager, Service {
 		IntentFilter filter = new IntentFilter(ACTION_BATTERY_CHANGED);
 		Intent i = appContext.registerReceiver(null, filter);
 		if (i == null) return false;
-		int status = i.getIntExtra(EXTRA_STATUS, -1);
-		return status == BATTERY_STATUS_CHARGING ||
-				status == BATTERY_STATUS_FULL;
+		int status = i.getIntExtra(EXTRA_PLUGGED, 0);
+		return status != 0;
 	}
 
 	@Override

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

@@ -32,9 +32,6 @@ import static java.util.concurrent.TimeUnit.MINUTES;
 @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;
 
@@ -55,7 +52,7 @@ class AndroidTorPlugin extends TorPlugin {
 				appContext.getSystemService(POWER_SERVICE);
 		if (pm == null) throw new AssertionError();
 		wakeLock = new RenewableWakeLock(pm, scheduler, PARTIAL_WAKE_LOCK,
-				WAKE_LOCK_TAG, 1, MINUTES);
+				getWakeLockTag(), 1, MINUTES);
 	}
 
 	@Override
@@ -87,4 +84,17 @@ 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/system/AndroidSystemModule.java

@@ -1,10 +1,13 @@
 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;
@@ -32,6 +35,13 @@ public class AndroidSystemModule {
 		return androidExecutor;
 	}
 
+	@Provides
+	@Singleton
+	@EventExecutor
+	Executor provideEventExecutor(AndroidExecutor androidExecutor) {
+		return androidExecutor::runOnUiThread;
+	}
+
 	@Provides
 	@Singleton
 	ResourceProvider provideResourceProvider(AndroidResourceProvider provider) {

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

@@ -112,6 +112,8 @@ 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();
@@ -128,6 +130,12 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 			will(returnValue(true));
 			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());
@@ -140,6 +148,8 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 		assertTrue(cacheFile.createNewFile());
 		assertTrue(potatoDir.mkdirs());
 		assertTrue(potatoFile.createNewFile());
+		assertTrue(filesDir.mkdirs());
+		assertTrue(externalCacheDir.mkdirs());
 
 		accountManager.deleteAccount();
 
@@ -153,6 +163,8 @@ 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

@@ -1,46 +1,44 @@
 dependencyVerification {
     verify = [
         'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
-        'com.android.tools.analytics-library:protos:26.2.1:protos-26.2.1.jar:2f371f5b1f551e85ab08be4d6a2873471b3d44afd1ebf6aa3298f3b796bf691f',
-        'com.android.tools.analytics-library:shared:26.2.1:shared-26.2.1.jar:4c1e4e705fa4d45f23aaea230557f6508155012d9c296337787c1d7b26a97f5a',
-        'com.android.tools.analytics-library:tracker:26.2.1:tracker-26.2.1.jar:4a624ecc976539f755ddb0bb8dfc2dd3d08326cfec59a098dbd70f701ca7fb75',
-        'com.android.tools.build:aapt2:3.2.1-4818971:aapt2-3.2.1-4818971-linux.jar:f431b6f96c91a2c155144b091a9c97d9805c589fe8efc9c930b6cd346cb60a1e',
-        'com.android.tools.build:apksig:3.2.1:apksig-3.2.1.jar:2b46f2feffea66037aab29e4261b2433c190194a6ef97b958511eb157f2ccba5',
-        'com.android.tools.build:apkzlib:3.2.1:apkzlib-3.2.1.jar:c39ad0313905932431fe81c8899c2cf39a4d92ad6c4edcaa4b25432f461452aa',
-        'com.android.tools.build:builder-model:3.2.1:builder-model-3.2.1.jar:a9f68e6abcec122f9cb5ad352d3f05a3eb03acbcdca95e4d25c16310c2c965ff',
-        'com.android.tools.build:builder-test-api:3.2.1:builder-test-api-3.2.1.jar:533ac6c2b5884bb54967a33791f2628dfdfac7981af39417a333b43d4379b6be',
-        'com.android.tools.build:builder:3.2.1:builder-3.2.1.jar:aedcbfd115dbe91d09b4113e66ef50589b558d0aa3b2f133b1d867c9b87fae83',
-        'com.android.tools.build:gradle-api:3.2.1:gradle-api-3.2.1.jar:57cf0ac5ac1dca8afdb3f62b94265e776e7dcfa641cc3844fb53a05193de208d',
-        'com.android.tools.build:manifest-merger:26.2.1:manifest-merger-26.2.1.jar:8830573263361035d38cfdcb51e2db94029c93865b21334f5fbf8a27984281a6',
-        'com.android.tools.ddms:ddmlib:26.2.1:ddmlib-26.2.1.jar:a4bf0a29a19980bf27269465cc782064656750b77c26728f82f9e148b705218b',
-        '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:26.2.1:kotlin-compiler-26.2.1.jar:daa064fd708f340ee25fb9823c4c74104ac77f1370b76d907eb9ae6daec0a2ae',
-        'com.android.tools.external.org-jetbrains:uast:26.2.1:uast-26.2.1.jar:f10f7258d2ab9189562cc0f9ad838c0378fdba439229173390a99de02ebac75b',
-        'com.android.tools.layoutlib:layoutlib-api:26.2.1:layoutlib-api-26.2.1.jar:ddbf4fca123733fa011595b1cc1f4ac2937ed327b60990711fafc33c775c2ade',
-        'com.android.tools.lint:lint-api:26.2.1:lint-api-26.2.1.jar:3b57e739de567b98bc9ab56c2c0ee66fc026b4adf5843e8f9804ca0666a6f66e',
-        'com.android.tools.lint:lint-checks:26.2.1:lint-checks-26.2.1.jar:c86f4cc9aaee722ee4ad70062f7b5af91e9b041914af27adc09f545ab0fb3bc6',
-        'com.android.tools.lint:lint-gradle-api:26.2.1:lint-gradle-api-26.2.1.jar:2283e7af32e301565f2a797e531f0fc8c648077d457afb3ffdddbee638976c2f',
-        'com.android.tools.lint:lint-gradle:26.2.1:lint-gradle-26.2.1.jar:8fd90b2f3ec788cbb9801c07ab3e1ea2255aa31a6093157d7ea0ff13d0315ecb',
-        'com.android.tools.lint:lint-kotlin:26.2.1:lint-kotlin-26.2.1.jar:7a6a5d2b18f69cf1b900d857c2632b4c683713c533295933b8b759f8cab4a877',
-        'com.android.tools.lint:lint:26.2.1:lint-26.2.1.jar:7848b82ae988b90dee259ae7c7e86e05cbf52db6cd21c8bbd38ce7df08f3f8c5',
-        'com.android.tools:annotations:26.2.1:annotations-26.2.1.jar:7391c6a1e080174b96e64ceb078dadd31ce4d8a2d2fee0ec65be202126f90f24',
-        'com.android.tools:common:26.2.1:common-26.2.1.jar:a50aab2d6411ff68f4004a87c7e93d87d8e980a0ec3b352246549897ea2d78e5',
-        'com.android.tools:dvlib:26.2.1:dvlib-26.2.1.jar:72a83bf2839b1df9b1fbf67ba45d1bfb9f966cd774da4320c762b2be8f1688aa',
-        'com.android.tools:repository:26.2.1:repository-26.2.1.jar:fa74dae09103faef703df38550ad8fa244c5b6d1bf90d6198be932292b3d9cc1',
-        'com.android.tools:sdk-common:26.2.1:sdk-common-26.2.1.jar:759d4b292ca69a35cf961fca377b54158fc6c88108978006999442e80a011cf4',
-        'com.android.tools:sdklib:26.2.1:sdklib-26.2.1.jar:248df7ad5eac4aeb6f96c394c76760de4b7b89ac056e54d0c21a739368b91b45',
+        'com.android.tools.analytics-library:protos:26.3.2:protos-26.3.2.jar:50238fb4298b297217b184b9cd93c14f83536fcee829eb0ca850bdb5b53251f0',
+        'com.android.tools.analytics-library:shared:26.3.2:shared-26.3.2.jar:ddd80dcf21905018b7c0583ba72b7282f446084d4952422609a09fbf8237ef71',
+        'com.android.tools.analytics-library:tracker:26.3.2:tracker-26.3.2.jar:28c575d2d1af003e96d7b375a668ee10b2673a2dd0f6438750aa8c3b42e7d0ad',
+        'com.android.tools.build:apksig:3.3.2:apksig-3.3.2.jar:84c4aaa20127c6c1fe6bdd334b3f5df71f54ad080be9029c8a10f43b6a908acd',
+        'com.android.tools.build:apkzlib:3.3.2:apkzlib-3.3.2.jar:d34e523278e5dff565eba3ef3c089d515b2b5cc7b47dc77e2f3465e5e47176ac',
+        'com.android.tools.build:builder-model:3.3.2:builder-model-3.3.2.jar:055e3db0ecee9e06b9f024034999a29cd92cb1885207b37542126bd8bcc57f46',
+        'com.android.tools.build:builder-test-api:3.3.2:builder-test-api-3.3.2.jar:0b2e4cd7615bbcad14a3c91fe45ae26693508d06e40ba06c5968b8bc24416618',
+        'com.android.tools.build:builder:3.3.2:builder-3.3.2.jar:65649704da7aef0487235fd326f0f2e99ed5cf958e80f204496e6e08a42bd9f5',
+        'com.android.tools.build:gradle-api:3.3.2:gradle-api-3.3.2.jar:3cbd47e41bb70330dd72ec2c9fe51e6173554b484a03829b5a2de9e00841e040',
+        'com.android.tools.build:manifest-merger:26.3.2:manifest-merger-26.3.2.jar:05c4a6d8b02fb9f08744876477d0a68547c03a8a9069b1f086684fa04af97c33',
+        'com.android.tools.ddms:ddmlib:26.3.2:ddmlib-26.3.2.jar:d248da8a563d6e46d2c7ebbf371a4877e00510f4ca763c0bb272d5a281bf8b85',
+        'com.android.tools.external.com-intellij:intellij-core:26.3.2:intellij-core-26.3.2.jar:6c5ecc968230e9f4dcd0fef28885379feace1f0cd8130de6f61d649c86139bf3',
+        'com.android.tools.external.com-intellij:kotlin-compiler:26.3.2:kotlin-compiler-26.3.2.jar:1007d9b07ccb49cd8eaf30fda10ed4681d4714f2f9ab2ecda39b4e539cc51bbe',
+        'com.android.tools.external.org-jetbrains:uast:26.3.2:uast-26.3.2.jar:5d1833e562ea4f38a89708dfde695f0a162cbd39d003d3dde818c3fdc2b05317',
+        'com.android.tools.layoutlib:layoutlib-api:26.3.2:layoutlib-api-26.3.2.jar:d7e61e874ab95f5c350dd38b6a95b5c9dbe0083a02001884264cdb390cb255b8',
+        'com.android.tools.lint:lint-api:26.3.2:lint-api-26.3.2.jar:5867dfd7fb4a4e161a816a5d29d045f9b542d34594c00a1efec46fb4cd0e1033',
+        'com.android.tools.lint:lint-checks:26.3.2:lint-checks-26.3.2.jar:4b163b9c93790d2771e92ba8de58a0d9e0671ffcf2ccef3cf496efd442e27517',
+        'com.android.tools.lint:lint-gradle-api:26.3.2:lint-gradle-api-26.3.2.jar:54cb282e0c054f9bed3f51302ce08b003c8ab7961dfd5a4f6de26c23cc23062f',
+        'com.android.tools.lint:lint-gradle:26.3.2:lint-gradle-26.3.2.jar:bb139615f4ce97d42cc394b9389b49b76a6eb85be6785a5d272991543b519013',
+        'com.android.tools.lint:lint:26.3.2:lint-26.3.2.jar:ef7b369f8a56a92ccb0f4c1c357666b9339e4a711a9d84747d446441746cfe4e',
+        'com.android.tools:annotations:26.3.2:annotations-26.3.2.jar:5bcce8e98b6a2f5ccf13ebcefd8f734e0b35f8b19e456575665631442ce1f7a1',
+        'com.android.tools:common:26.3.2:common-26.3.2.jar:d9f8e7f0669e9a701568e3db6a87c89cf12d8fa6811c9991e969f950215ecfac',
+        'com.android.tools:dvlib:26.3.2:dvlib-26.3.2.jar:d84aad56161c7773579303d69714ded6897c64c6ddfd7d456e453231e4dfe811',
+        'com.android.tools:repository:26.3.2:repository-26.3.2.jar:da611eeb06e9ab8750d25b9e2901e10db8e5ec6304eb4c8b7103d39e0921ea40',
+        'com.android.tools:sdk-common:26.3.2:sdk-common-26.3.2.jar:82823a3bf25e64fac33a286490f0cf5ac50c2cdb3c540149b030896bb44bf96c',
+        'com.android.tools:sdklib:26.3.2:sdklib-26.3.2.jar:424d15492af67321900963238646d27495ab60de2a5b19e6a416963bc5d6932b',
         'com.google.code.findbugs:jsr305:1.3.9:jsr305-1.3.9.jar:905721a0eea90a81534abb7ee6ef4ea2e5e645fa1def0a5cd88402df1b46c9ed',
+        'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
         'com.google.code.gson:gson:2.8.0:gson-2.8.0.jar:c6221763bd79c4f1c3dc7f750b5f29a0bb38b367b81314c4f71896e340c40825',
         'com.google.dagger:dagger-compiler:2.19:dagger-compiler-2.19.jar:27a4b202a2de908182edb261f8c0a264e08e5e4733d7514bc7fbf0d31da5c0fc',
         'com.google.dagger:dagger-producers:2.19:dagger-producers-2.19.jar:a17663abe0fc38b676026950907d4c5f5e2bf338375415861eaff6e3bdb0b768',
         'com.google.dagger:dagger-spi:2.19:dagger-spi-2.19.jar:e7a6379d82c841f6aac2866948ad1eed716528707814602842a8d844ce04e2e1',
         '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:guava:23.0:guava-23.0.jar:7baa80df284117e5b945b19b98d367a85ea7b7801bd358ff657946c3bd1b6596',
         'com.google.guava:guava:25.0-jre:guava-25.0-jre.jar:3fd4341776428c7e0e5c18a7c10de129475b69ab9d30aeafbb5c277bb6074fa9',
+        'com.google.guava:guava:26.0-jre:guava-26.0-jre.jar:a0e9cabad665bc20bcd2b01f108e5fc03f756e13aea80abaadb9f407033bea2c',
         'com.google.j2objc:j2objc-annotations:1.1:j2objc-annotations-1.1.jar:40ceb7157feb263949e0f503fe5f71689333a621021aa20ce0d0acee3badaa0f',
         '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',
@@ -68,21 +66,22 @@ dependencyVerification {
         '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:0.0.7:obfs4proxy-android-0.0.7.zip:abdfb5d889d848de9bf214f9276abbf454808a505b870819eccc9a9e985bf617',
-        'org.briarproject:tor-android:0.3.4.8:tor-android-0.3.4.8.zip:989a0352d9d8d8172cd6c2137654e165e5d2beb10ed1211bab3814e224ad1926',
+        'org.briarproject:obfs4proxy-android:0.0.9:obfs4proxy-android-0.0.9.zip:9b7e9181535ea8d8bbe8ae6338e08cf4c5fc1e357a779393e0ce49586d459ae0',
+        'org.briarproject:tor-android:0.3.5.8:tor-android-0.3.5.8.zip:42a13a6f185be1a62f42e3f30ce66a3c099ac5ec890a65e7593111b65b44a54a',
         'org.checkerframework:checker-compat-qual:2.5.3:checker-compat-qual-2.5.3.jar:d76b9afea61c7c082908023f0cbc1427fab9abd2df915c8b8a3e7a509bccbc6d',
-        'org.codehaus.groovy:groovy-all:2.4.12:groovy-all-2.4.12.jar:6a56af4bd48903d56bec62821876cadefafd007360cc6bd0d8f7aa8d72b38be4',
+        'org.checkerframework:checker-qual:2.5.2:checker-qual-2.5.2.jar:64b02691c8b9d4e7700f8ee2e742dce7ea2c6e81e662b7522c9ee3bf568c040a',
+        '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.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:1.2.0:kotlin-reflect-1.2.0.jar:4f48a872bad6e4d9c053f4ad610d11e4012ad7e58dc19a03dd5eb811f36069dd',
-        'org.jetbrains.kotlin:kotlin-stdlib-common:1.2.71:kotlin-stdlib-common-1.2.71.jar:63999687ff2fce8a592dd180ffbbf8f1d21c26b4044c55cdc74ff3cf3b3cf328',
-        'org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.2.71:kotlin-stdlib-jdk7-1.2.71.jar:b136bd61b240e07d4d92ce00d3bd1dbf584400a7bf5f220c2f3cd22446858082',
-        'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.2.71:kotlin-stdlib-jdk8-1.2.71.jar:ac3c8abf47790b64b4f7e2509a53f0c145e061ac1612a597520535d199946ea9',
-        'org.jetbrains.kotlin:kotlin-stdlib:1.2.71:kotlin-stdlib-1.2.71.jar:4c895c270b87f5fec2a2796e1d89c15407ee821de961527c28588bb46afbc68b',
+        'org.jetbrains.kotlin:kotlin-reflect:1.3.21:kotlin-reflect-1.3.21.jar:a3065c822633191e0a3e3ee12a29bec234fc4b2864a6bb87ef48cce3e9e0c26a',
+        'org.jetbrains.kotlin:kotlin-stdlib-common:1.3.21:kotlin-stdlib-common-1.3.21.jar:cea61f7b611895e64f58569a9757fc0ab0d582f107211e1930e0ce2a0add52a7',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.3.21:kotlin-stdlib-jdk7-1.3.21.jar:a87875604fd42140da6938ae4d35ee61081f4482536efc6d2615b8b626a198af',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.3.21:kotlin-stdlib-jdk8-1.3.21.jar:5823ed66ac122a1c55442ebca5a209a843ccd87f562edc31a787f3d2e47f74d4',
+        'org.jetbrains.kotlin:kotlin-stdlib:1.3.21:kotlin-stdlib-1.3.21.jar:38ba2370d9f06f50433e06b2ca775b94473c2e2785f410926079ab793c72b034',
         '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/src/main/java/org/briarproject/bramble/api/client/ContactGroupFactory.java

@@ -18,11 +18,10 @@ public interface ContactGroupFactory {
 	 * Creates a group for the given client to share with the given contact.
 	 */
 	Group createContactGroup(ClientId clientId, int majorVersion,
-			Contact contact);
+			Contact contact, AuthorId local);
 
 	/**
-	 * Creates a group for the given client to share between the given authors
-	 * identified by their AuthorIds.
+	 * Creates a group for the given client to share between the given authors.
 	 */
 	Group createContactGroup(ClientId clientId, int majorVersion,
 			AuthorId authorId1, AuthorId authorId2);

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

@@ -1,13 +1,13 @@
 package org.briarproject.bramble.api.contact;
 
 import org.briarproject.bramble.api.identity.Author;
-import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
 import static org.briarproject.bramble.util.StringUtils.toUtf8;
 
 @Immutable
@@ -16,24 +16,28 @@ public class Contact {
 
 	private final ContactId id;
 	private final Author author;
-	private final AuthorId localAuthorId;
 	@Nullable
 	private final String alias;
-	private final boolean verified, active;
+	@Nullable
+	private final byte[] handshakePublicKey;
+	private final boolean verified;
 
-	public Contact(ContactId id, Author author, AuthorId localAuthorId,
-			@Nullable String alias, boolean verified, boolean active) {
+	public Contact(ContactId id, Author author, @Nullable String alias,
+			@Nullable byte[] handshakePublicKey, boolean verified) {
 		if (alias != null) {
 			int aliasLength = toUtf8(alias).length;
 			if (aliasLength == 0 || aliasLength > MAX_AUTHOR_NAME_LENGTH)
 				throw new IllegalArgumentException();
 		}
+		if (handshakePublicKey != null && (handshakePublicKey.length == 0 ||
+				handshakePublicKey.length > MAX_PUBLIC_KEY_LENGTH)) {
+			throw new IllegalArgumentException();
+		}
 		this.id = id;
 		this.author = author;
-		this.localAuthorId = localAuthorId;
 		this.alias = alias;
+		this.handshakePublicKey = handshakePublicKey;
 		this.verified = verified;
-		this.active = active;
 	}
 
 	public ContactId getId() {
@@ -44,21 +48,18 @@ public class Contact {
 		return author;
 	}
 
-	public AuthorId getLocalAuthorId() {
-		return localAuthorId;
-	}
-
 	@Nullable
 	public String getAlias() {
 		return alias;
 	}
 
-	public boolean isVerified() {
-		return verified;
+	@Nullable
+	public byte[] getHandshakePublicKey() {
+		return handshakePublicKey;
 	}
 
-	public boolean isActive() {
-		return active;
+	public boolean isVerified() {
+		return verified;
 	}
 
 	@Override

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

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

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

@@ -18,31 +18,30 @@ public interface ContactExchangeTask {
 	byte PROTOCOL_VERSION = 1;
 
 	/**
-	 * Label for deriving Alice's header key from the master secret.
+	 * Label for deriving Alice's header key from the master key.
 	 */
 	String ALICE_KEY_LABEL =
 			"org.briarproject.bramble.contact/ALICE_HEADER_KEY";
 
 	/**
-	 * Label for deriving Bob's header key from the master secret.
+	 * Label for deriving Bob's header key from the master key.
 	 */
 	String BOB_KEY_LABEL = "org.briarproject.bramble.contact/BOB_HEADER_KEY";
 
 	/**
-	 * Label for deriving Alice's key binding nonce from the master secret.
+	 * Label for deriving Alice's key binding nonce from the master key.
 	 */
 	String ALICE_NONCE_LABEL = "org.briarproject.bramble.contact/ALICE_NONCE";
 
 	/**
-	 * Label for deriving Bob's key binding nonce from the master secret.
+	 * Label for deriving Bob's key binding nonce from the master key.
 	 */
 	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,
+	void startExchange(LocalAuthor localAuthor, SecretKey masterKey,
 			DuplexTransportConnection conn, TransportId transportId,
 			boolean alice);
 }

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

@@ -24,61 +24,80 @@ public interface ContactManager {
 	void registerContactHook(ContactHook hook);
 
 	/**
-	 * Stores a contact associated with the given local and remote pseudonyms,
-	 * derives and stores transport keys for each transport, and returns an ID
-	 * for the contact.
+	 * Stores a contact with the given pseudonym, derives and stores transport
+	 * keys for each transport, and returns an ID for the contact.
 	 *
 	 * @param alice true if the local party is Alice
 	 */
-	ContactId addContact(Transaction txn, Author remote, AuthorId local,
-			SecretKey master, long timestamp, boolean alice, boolean verified,
-			boolean active) throws DbException;
-
-	/**
-	 * Stores a contact associated with the given local and remote pseudonyms
-	 * and returns an ID for the contact.
-	 */
-	ContactId addContact(Transaction txn, Author remote, AuthorId local,
-			boolean verified, boolean active) throws DbException;
-
-	/**
-	 * Stores a contact associated with the given local and remote pseudonyms,
-	 * derives and stores transport keys for each transport, and returns an ID
-	 * for the contact.
-	 *
-	 * @param alice true if the local party is Alice
-	 */
-	ContactId addContact(Author remote, AuthorId local, SecretKey master,
+	ContactId addContact(Transaction txn, Author a, SecretKey rootKey,
 			long timestamp, boolean alice, boolean verified, boolean active)
 			throws DbException;
 
+	/**
+	 * Stores a contact with the given pseudonym and returns an ID for the
+	 * contact.
+	 */
+	ContactId addContact(Transaction txn, Author a, boolean verified)
+			throws DbException;
+
+	/**
+	 * Stores a contact with the given pseudonym, derives and stores transport
+	 * keys for each transport, and returns an ID for the contact.
+	 *
+	 * @param alice true if the local party is Alice
+	 */
+	ContactId addContact(Author a, SecretKey rootKey, long timestamp,
+			boolean alice, boolean verified, boolean active) throws DbException;
+
+	/**
+	 * Returns the static link that needs to be sent to the contact to be added.
+	 */
+	String getRemoteContactLink();
+
+	/**
+	 * Returns true if the given link is syntactically valid.
+	 */
+	boolean isValidRemoteContactLink(String link);
+
+	/**
+	 * Requests a new contact to be added via the given {@code link}.
+	 *
+	 * @param link The link received from the contact we want to add.
+	 * @param alias The alias the user has given this contact.
+	 * @return A PendingContact representing the contact to be added.
+	 */
+	PendingContact addRemoteContactRequest(String link, String alias);
+
+	/**
+	 * Returns a list of {@link PendingContact}s.
+	 */
+	Collection<PendingContact> getPendingContacts();
+
+	/**
+	 * Removes a {@link PendingContact} that is in state
+	 * {@link PendingContactState FAILED}.
+	 */
+	void removePendingContact(PendingContact pendingContact);
+
 	/**
 	 * Returns the contact with the given ID.
 	 */
 	Contact getContact(ContactId c) throws DbException;
 
 	/**
-	 * Returns the contact with the given remoteAuthorId
-	 * that was added by the LocalAuthor with the given localAuthorId
-	 *
-	 * @throws org.briarproject.bramble.api.db.NoSuchContactException
+	 * Returns the contact with the given ID.
 	 */
-	Contact getContact(AuthorId remoteAuthorId, AuthorId localAuthorId)
-			throws DbException;
+	Contact getContact(AuthorId a) throws DbException;
 
 	/**
-	 * Returns the contact with the given remoteAuthorId
-	 * that was added by the LocalAuthor with the given localAuthorId
-	 *
-	 * @throws org.briarproject.bramble.api.db.NoSuchContactException
+	 * Returns the contact with the given ID.
 	 */
-	Contact getContact(Transaction txn, AuthorId remoteAuthorId,
-			AuthorId localAuthorId) throws DbException;
+	Contact getContact(Transaction txn, AuthorId a) throws DbException;
 
 	/**
 	 * Returns all active contacts.
 	 */
-	Collection<Contact> getActiveContacts() throws DbException;
+	Collection<Contact> getContacts() throws DbException;
 
 	/**
 	 * Removes a contact and all associated state.
@@ -90,12 +109,6 @@ public interface ContactManager {
 	 */
 	void removeContact(Transaction txn, ContactId c) throws DbException;
 
-	/**
-	 * Marks a contact as active or inactive.
-	 */
-	void setContactActive(Transaction txn, ContactId c, boolean active)
-			throws DbException;
-
 	/**
 	 * Sets an alias name for the contact or unsets it if alias is null.
 	 */
@@ -109,16 +122,14 @@ public interface ContactManager {
 			throws DbException;
 
 	/**
-	 * Return true if a contact with this name and public key already exists
+	 * Returns true if a contact with this pseudonym already exists.
 	 */
-	boolean contactExists(Transaction txn, AuthorId remoteAuthorId,
-			AuthorId localAuthorId) throws DbException;
+	boolean contactExists(Transaction txn, AuthorId a) throws DbException;
 
 	/**
-	 * Return true if a contact with this name and public key already exists
+	 * Returns true if a contact with this pseudonym already exists.
 	 */
-	boolean contactExists(AuthorId remoteAuthorId, AuthorId localAuthorId)
-			throws DbException;
+	boolean contactExists(AuthorId a) throws DbException;
 
 	/**
 	 * Returns the {@link AuthorInfo} for the given author.

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

@@ -0,0 +1,56 @@
+package org.briarproject.bramble.api.contact;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+public class PendingContact {
+
+	private final PendingContactId id;
+	private final byte[] publicKey;
+	private final String alias;
+	private final PendingContactState state;
+	private final long timestamp;
+
+	public PendingContact(PendingContactId id, byte[] publicKey,
+			String alias, 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 byte[] getPublicKey() {
+		return publicKey;
+	}
+
+	public String getAlias() {
+		return alias;
+	}
+
+	public PendingContactState getState() {
+		return state;
+	}
+
+	public long getTimestamp() {
+		return timestamp;
+	}
+
+	@Override
+	public int hashCode() {
+		return id.hashCode();
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		return o instanceof PendingContact &&
+				id.equals(((PendingContact) o).id);
+	}
+}

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

@@ -0,0 +1,25 @@
+package org.briarproject.bramble.api.contact;
+
+import org.briarproject.bramble.api.UniqueId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+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(Object o) {
+		return o instanceof PendingContactId && super.equals(o);
+	}
+}

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

@@ -0,0 +1,30 @@
+package org.briarproject.bramble.api.contact;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+public enum PendingContactState {
+
+	WAITING_FOR_CONNECTION(0),
+	CONNECTED(1),
+	ADDING_CONTACT(2),
+	FAILED(3);
+
+	private final int value;
+
+	PendingContactState(int value) {
+		this.value = value;
+	}
+
+	public int getValue() {
+		return value;
+	}
+
+	public static PendingContactState fromValue(int value) {
+		for (PendingContactState s : values()) if (s.value == value) return s;
+		throw new IllegalArgumentException();
+	}
+}

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

@@ -14,18 +14,12 @@ import javax.annotation.concurrent.Immutable;
 public class ContactAddedEvent extends Event {
 
 	private final ContactId contactId;
-	private final boolean active;
 
-	public ContactAddedEvent(ContactId contactId, boolean active) {
+	public ContactAddedEvent(ContactId contactId) {
 		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/ContactExchangeFailedEvent.java

@@ -0,0 +1,32 @@
+package org.briarproject.bramble.api.contact.event;
+
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.Nullable;
+
+@NotNullByDefault
+public class ContactExchangeFailedEvent extends Event {
+
+	@Nullable
+	private final Author duplicateRemoteAuthor;
+
+	public ContactExchangeFailedEvent(@Nullable Author duplicateRemoteAuthor) {
+		this.duplicateRemoteAuthor = duplicateRemoteAuthor;
+	}
+
+	public ContactExchangeFailedEvent() {
+		this(null);
+	}
+
+	@Nullable
+	public Author getDuplicateRemoteAuthor() {
+		return duplicateRemoteAuthor;
+	}
+
+	public boolean wasDuplicateContact() {
+		return duplicateRemoteAuthor != null;
+	}
+
+}

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

@@ -0,0 +1,20 @@
+package org.briarproject.bramble.api.contact.event;
+
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public class ContactExchangeSucceededEvent extends Event {
+
+	private final Author remoteAuthor;
+
+	public ContactExchangeSucceededEvent(Author remoteAuthor) {
+		this.remoteAuthor = remoteAuthor;
+	}
+
+	public Author getRemoteAuthor() {
+		return remoteAuthor;
+	}
+
+}

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

@@ -1,31 +0,0 @@
-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/PendingContactStateChangedEvent.java

@@ -0,0 +1,34 @@
+package org.briarproject.bramble.api.contact.event;
+
+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;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that is broadcast when a pending contact's state is changed.
+ */
+@Immutable
+@NotNullByDefault
+public class PendingContactStateChangedEvent extends Event {
+
+	private final PendingContactId id;
+	private final PendingContactState state;
+
+	public PendingContactStateChangedEvent(PendingContactId id,
+			PendingContactState state) {
+		this.id = id;
+		this.state = state;
+	}
+
+	public PendingContactId getId() {
+		return id;
+	}
+
+	public PendingContactState getPendingContactState() {
+		return state;
+	}
+
+}

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/akwizgran/briar-spec/blob/master/protocols/BQP.md
+ * https://code.briarproject.org/briar/briar-spec/blob/master/protocols/BQP.md
  */
 public interface KeyAgreementCrypto {
 

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

@@ -1,29 +1,45 @@
 package org.briarproject.bramble.api.crypto;
 
 import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.transport.HandshakeKeys;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
 /**
  * Crypto operations for the transport security protocol - see
- * https://code.briarproject.org/akwizgran/briar-spec/blob/master/protocols/BTP.md
+ * https://code.briarproject.org/briar/briar-spec/blob/master/protocols/BTP.md
  */
 public interface TransportCrypto {
 
 	/**
 	 * Derives initial transport keys for the given transport in the given
-	 * rotation period from the given master secret.
+	 * time period from the given root key.
 	 *
 	 * @param alice whether the keys are for use by Alice or Bob.
 	 * @param active whether the keys are usable for outgoing streams.
 	 */
-	TransportKeys deriveTransportKeys(TransportId t, SecretKey master,
-			long rotationPeriod, boolean alice, boolean active);
+	TransportKeys deriveTransportKeys(TransportId t, SecretKey rootKey,
+			long timePeriod, boolean alice, boolean active);
 
 	/**
-	 * Rotates the given transport keys to the given rotation period. If the
-	 * keys are for the given period or any later period they are not rotated.
+	 * Rotates the given transport keys to the given time period. If the keys
+	 * are for the given period or any later period they are not rotated.
 	 */
-	TransportKeys rotateTransportKeys(TransportKeys k, long rotationPeriod);
+	TransportKeys rotateTransportKeys(TransportKeys k, long timePeriod);
+
+	/**
+	 * 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.
+	 */
+	HandshakeKeys deriveHandshakeKeys(TransportId t, SecretKey rootKey,
+			long timePeriod, boolean alice);
+
+	/**
+	 * Updates the given handshake keys to the given time period. If the keys
+	 * are for the given period or any later period they are not updated.
+	 */
+	HandshakeKeys updateHandshakeKeys(HandshakeKeys k, long timePeriod);
 
 	/**
 	 * Encodes the pseudo-random tag that is used to recognise a stream.

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

@@ -0,0 +1,20 @@
+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/DatabaseComponent.java

@@ -2,6 +2,8 @@ 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.SecretKey;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
@@ -20,8 +22,11 @@ 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.HandshakeKeySet;
+import org.briarproject.bramble.api.transport.HandshakeKeySetId;
+import org.briarproject.bramble.api.transport.HandshakeKeys;
+import org.briarproject.bramble.api.transport.TransportKeySet;
+import org.briarproject.bramble.api.transport.TransportKeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.util.Collection;
@@ -97,17 +102,31 @@ public interface DatabaseComponent {
 			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.
+	 * Stores a contact with the given pseudonym and returns an ID for the
+	 * contact.
 	 */
-	ContactId addContact(Transaction txn, Author remote, AuthorId local,
-			boolean verified, boolean active) throws DbException;
+	ContactId addContact(Transaction txn, Author a, boolean verified)
+			throws DbException;
 
 	/**
 	 * Stores a group.
 	 */
 	void addGroup(Transaction txn, Group g) throws DbException;
 
+	/**
+	 * Stores the given handshake keys for the given contact and returns a
+	 * key set ID.
+	 */
+	HandshakeKeySetId addHandshakeKeys(Transaction txn, ContactId c,
+			HandshakeKeys k) throws DbException;
+
+	/**
+	 * Stores the given handshake keys for the given pending contact and
+	 * returns a key set ID.
+	 */
+	HandshakeKeySetId addHandshakeKeys(Transaction txn, PendingContactId p,
+			HandshakeKeys k) throws DbException;
+
 	/**
 	 * Stores a local pseudonym.
 	 */
@@ -119,6 +138,12 @@ public interface DatabaseComponent {
 	void addLocalMessage(Transaction txn, Message m, Metadata meta,
 			boolean shared) throws DbException;
 
+	/**
+	 * Stores a pending contact.
+	 */
+	void addPendingContact(Transaction txn, PendingContact p)
+			throws DbException;
+
 	/**
 	 * Stores a transport.
 	 */
@@ -129,27 +154,39 @@ public interface DatabaseComponent {
 	 * Stores the given transport keys for the given contact and returns a
 	 * key set ID.
 	 */
-	KeySetId addTransportKeys(Transaction txn, ContactId c,
+	TransportKeySetId addTransportKeys(Transaction txn, ContactId c,
 			TransportKeys k) throws DbException;
 
 	/**
-	 * Returns true if the database contains the given contact for the given
-	 * local pseudonym.
+	 * Returns true if the database contains the given contact.
+	 * <p/>
+	 * Read-only.
 	 */
-	boolean containsContact(Transaction txn, AuthorId remote, AuthorId local)
-			throws DbException;
+	boolean containsContact(Transaction txn, AuthorId a) 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 the given local author.
+	 * <p/>
+	 * Read-only.
 	 */
 	boolean containsLocalAuthor(Transaction txn, AuthorId local)
 			throws DbException;
 
+	/**
+	 * Returns true if the database contains the given pending contact.
+	 * <p/>
+	 * Read-only.
+	 */
+	boolean containsPendingContact(Transaction txn, PendingContactId p)
+			throws DbException;
+
 	/**
 	 * Deletes the message with the given ID. Unlike
 	 * {@link #removeMessage(Transaction, MessageId)}, the message ID,
@@ -208,24 +245,6 @@ public interface DatabaseComponent {
 	Collection<Message> generateRequestedBatch(Transaction txn, ContactId c,
 			int maxLength, int maxLatency) throws DbException;
 
-	/**
-	 * Returns the number of blocks in the given message.
-	 * <p>
-	 * Read-only.
-	 */
-	int getBlockCount(Transaction txn, MessageId m) throws DbException;
-
-	/**
-	 * Returns the given block of the given message.
-	 * <p>
-	 * Read-only.
-	 *
-	 * @throws NoSuchBlockException if 'blockNumber' is greater than or equal
-	 * to the number of blocks in the message
-	 */
-	byte[] getBlock(Transaction txn, MessageId m, int blockNumber)
-			throws DbException;
-
 	/**
 	 * Returns the contact with the given ID.
 	 * <p/>
@@ -233,6 +252,13 @@ public interface DatabaseComponent {
 	 */
 	Contact getContact(Transaction txn, ContactId c) throws DbException;
 
+	/**
+	 * Returns the contact with the given author ID.
+	 * <p/>
+	 * Read-only.
+	 */
+	Contact getContact(Transaction txn, AuthorId a) throws DbException;
+
 	/**
 	 * Returns all contacts.
 	 * <p/>
@@ -240,22 +266,6 @@ public interface DatabaseComponent {
 	 */
 	Collection<Contact> getContacts(Transaction txn) throws DbException;
 
-	/**
-	 * Returns a possibly empty collection of contacts with the given author ID.
-	 * <p/>
-	 * Read-only.
-	 */
-	Collection<Contact> getContactsByAuthorId(Transaction txn, AuthorId remote)
-			throws DbException;
-
-	/**
-	 * Returns all contacts associated with the given local pseudonym.
-	 * <p/>
-	 * Read-only.
-	 */
-	Collection<ContactId> getContacts(Transaction txn, AuthorId a)
-			throws DbException;
-
 	/**
 	 * Returns the group with the given ID.
 	 * <p/>
@@ -287,6 +297,14 @@ public interface DatabaseComponent {
 	Visibility getGroupVisibility(Transaction txn, ContactId c, GroupId g)
 			throws DbException;
 
+	/**
+	 * Returns all handshake keys for the given transport.
+	 * <p/>
+	 * Read-only.
+	 */
+	Collection<HandshakeKeySet> getHandshakeKeys(Transaction txn, TransportId t)
+			throws DbException;
+
 	/**
 	 * Returns the local pseudonym with the given ID.
 	 * <p/>
@@ -435,6 +453,14 @@ public interface DatabaseComponent {
 	 */
 	long getNextSendTime(Transaction txn, ContactId c) throws DbException;
 
+	/**
+	 * Returns all pending contacts.
+	 * <p/>
+	 * Read-only.
+	 */
+	Collection<PendingContact> getPendingContacts(Transaction txn)
+			throws DbException;
+
 	/**
 	 * Returns all settings in the given namespace.
 	 * <p/>
@@ -447,14 +473,20 @@ public interface DatabaseComponent {
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<KeySet> getTransportKeys(Transaction txn, TransportId t)
+	Collection<TransportKeySet> getTransportKeys(Transaction txn, TransportId t)
 			throws DbException;
 
+	/**
+	 * Increments the outgoing stream counter for the given handshake keys.
+	 */
+	void incrementStreamCounter(Transaction txn, TransportId t,
+			HandshakeKeySetId k) throws DbException;
+
 	/**
 	 * Increments the outgoing stream counter for the given transport keys.
 	 */
-	void incrementStreamCounter(Transaction txn, TransportId t, KeySetId k)
-			throws DbException;
+	void incrementStreamCounter(Transaction txn, TransportId t,
+			TransportKeySetId k) throws DbException;
 
 	/**
 	 * Merges the given metadata with the existing metadata for the given
@@ -509,6 +541,12 @@ public interface DatabaseComponent {
 	 */
 	void removeGroup(Transaction txn, Group g) throws DbException;
 
+	/**
+	 * Removes the given handshake keys from the database.
+	 */
+	void removeHandshakeKeys(Transaction txn, TransportId t,
+			HandshakeKeySetId k) throws DbException;
+
 	/**
 	 * Removes a local pseudonym (and all associated state) from the database.
 	 */
@@ -519,6 +557,12 @@ public interface DatabaseComponent {
 	 */
 	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 a transport (and all associated state) from the database.
 	 */
@@ -527,20 +571,14 @@ public interface DatabaseComponent {
 	/**
 	 * Removes the given transport keys from the database.
 	 */
-	void removeTransportKeys(Transaction txn, TransportId t, KeySetId k)
-			throws DbException;
+	void removeTransportKeys(Transaction txn, TransportId t,
+			TransportKeySetId k) throws DbException;
 
 	/**
 	 * Marks the given contact as verified.
 	 */
 	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.
 	 */
@@ -571,21 +609,36 @@ public interface DatabaseComponent {
 			Collection<MessageId> dependencies) throws DbException;
 
 	/**
-	 * Sets the reordering window for the given key set and transport in the
-	 * given rotation period.
+	 * Sets the reordering window for the given transport key set in the given
+	 * time period.
 	 */
-	void setReorderingWindow(Transaction txn, KeySetId k, TransportId t,
-			long rotationPeriod, long base, byte[] bitmap) throws DbException;
+	void setReorderingWindow(Transaction txn, TransportKeySetId k,
+			TransportId t, long timePeriod, long base, byte[] bitmap)
+			throws DbException;
+
+	/**
+	 * Sets the reordering window for the given handshake key set in the given
+	 * time period.
+	 */
+	void setReorderingWindow(Transaction txn, HandshakeKeySetId k,
+			TransportId t, long timePeriod, long base, byte[] bitmap)
+			throws DbException;
 
 	/**
 	 * Marks the given transport keys as usable for outgoing streams.
 	 */
-	void setTransportKeysActive(Transaction txn, TransportId t, KeySetId k)
+	void setTransportKeysActive(Transaction txn, TransportId t,
+			TransportKeySetId k) throws DbException;
+
+	/**
+	 * Stores the given handshake keys, deleting any keys they have replaced.
+	 */
+	void updateHandshakeKeys(Transaction txn, Collection<HandshakeKeySet> keys)
 			throws DbException;
 
 	/**
 	 * Stores the given transport keys, deleting any keys they have replaced.
 	 */
-	void updateTransportKeys(Transaction txn, Collection<KeySet> keys)
+	void updateTransportKeys(Transaction txn, Collection<TransportKeySet> keys)
 			throws DbException;
 }

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

@@ -10,6 +10,4 @@ public interface DatabaseConfig {
 	File getDatabaseDirectory();
 
 	File getDatabaseKeyDirectory();
-
-	long getMaxSize();
 }

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

@@ -0,0 +1,24 @@
+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/NoSuchBlockException.java

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

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

@@ -0,0 +1,9 @@
+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

@@ -0,0 +1,9 @@
+package org.briarproject.bramble.api.db;
+
+/**
+ * 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 {
+}

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

@@ -0,0 +1,24 @@
+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

@@ -1,13 +1,15 @@
 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.Collections;
 import java.util.List;
 
 import javax.annotation.concurrent.NotThreadSafe;
 
+import static java.util.Collections.emptyList;
+
 /**
  * A wrapper around a database transaction. Transactions are not thread-safe.
  */
@@ -17,7 +19,7 @@ public class Transaction {
 	private final Object txn;
 	private final boolean readOnly;
 
-	private List<Event> events = null;
+	private List<CommitAction> actions = null;
 	private boolean committed = false;
 
 	public Transaction(Object txn, boolean readOnly) {
@@ -42,19 +44,27 @@ public class Transaction {
 
 	/**
 	 * Attaches an event to be broadcast when the transaction has been
-	 * committed.
+	 * committed. The event will be broadcast on the {@link EventExecutor}.
 	 */
 	public void attach(Event e) {
-		if (events == null) events = new ArrayList<>();
-		events.add(e);
+		if (actions == null) actions = new ArrayList<>();
+		actions.add(new EventAction(e));
 	}
 
 	/**
-	 * Returns any events attached to the transaction.
+	 * Attaches a task to be executed when the transaction has been
+	 * committed. The task will be run on the {@link EventExecutor}.
 	 */
-	public List<Event> getEvents() {
-		if (events == null) return Collections.emptyList();
-		return events;
+	public void attach(Runnable r) {
+		if (actions == null) actions = new ArrayList<>();
+		actions.add(new TaskAction(r));
+	}
+
+	/**
+	 * 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/event/EventBus.java

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

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

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

@@ -12,5 +12,6 @@ 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/LocalAuthor.java

@@ -2,8 +2,11 @@ package org.briarproject.bramble.api.identity;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
+import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 
+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
+
 /**
  * A pseudonym for the local user.
  */
@@ -12,6 +15,8 @@ import javax.annotation.concurrent.Immutable;
 public class LocalAuthor extends Author {
 
 	private final byte[] privateKey;
+	@Nullable
+	private final byte[] handshakePublicKey, handshakePrivateKey;
 	private final long created;
 
 	public LocalAuthor(AuthorId id, int formatVersion, String name,
@@ -19,6 +24,22 @@ public class LocalAuthor extends Author {
 		super(id, formatVersion, name, publicKey);
 		this.privateKey = privateKey;
 		this.created = created;
+		handshakePublicKey = null;
+		handshakePrivateKey = null;
+	}
+
+	public LocalAuthor(AuthorId id, int formatVersion, String name,
+			byte[] publicKey, byte[] privateKey, byte[] handshakePublicKey,
+			byte[] handshakePrivateKey, long created) {
+		super(id, formatVersion, name, publicKey);
+		if (handshakePublicKey.length == 0 ||
+				handshakePublicKey.length > MAX_PUBLIC_KEY_LENGTH) {
+			throw new IllegalArgumentException();
+		}
+		this.privateKey = privateKey;
+		this.handshakePublicKey = handshakePublicKey;
+		this.handshakePrivateKey = handshakePrivateKey;
+		this.created = created;
 	}
 
 	/**
@@ -28,6 +49,22 @@ public class LocalAuthor extends Author {
 		return privateKey;
 	}
 
+	/**
+	 * Returns the public key used for handshaking, or null if no key exists.
+	 */
+	@Nullable
+	public byte[] getHandshakePublicKey() {
+		return handshakePublicKey;
+	}
+
+	/**
+	 * Returns the private key used for handshaking, or null if no key exists.
+	 */
+	@Nullable
+	public byte[] getHandshakePrivateKey() {
+		return handshakePrivateKey;
+	}
+
 	/**
 	 * Returns the time the pseudonym was created, in milliseconds since the
 	 * Unix epoch.

bramble-api/src/main/java/org/briarproject/bramble/api/io/BlockSource.java

@@ -1,21 +0,0 @@
-package org.briarproject.bramble.api.io;
-
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.db.NoSuchBlockException;
-import org.briarproject.bramble.api.sync.MessageId;
-
-public interface BlockSource {
-
-	/**
-	 * Returns the number of blocks in the given message.
-	 */
-	int getBlockCount(MessageId m) throws DbException;
-
-	/**
-	 * Returns the given block of the given message.
-	 *
-	 * @throws NoSuchBlockException if 'blockNumber' is greater than or equal
-	 * to the number of blocks in the message
-	 */
-	byte[] getBlock(MessageId m, int blockNumber) throws DbException;
-}

bramble-api/src/main/java/org/briarproject/bramble/api/io/MessageInputStreamFactory.java

@@ -1,17 +0,0 @@
-package org.briarproject.bramble.api.io;
-
-import org.briarproject.bramble.api.sync.MessageId;
-
-import java.io.IOException;
-import java.io.InputStream;
-
-public interface MessageInputStreamFactory {
-
-	/**
-	 * Returns an {@link InputStream} for reading the given message from the
-	 * database. This method returns immediately. If the message is not in the
-	 * database or cannot be read, reading from the stream will throw an
-	 * {@link IOException};
-	 */
-	InputStream getMessageInputStream(MessageId m);
-}

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 secret.
+	 * Label for deriving the master key.
 	 */
-	String MASTER_SECRET_LABEL =
+	String MASTER_KEY_LABEL =
 			"org.briarproject.bramble.keyagreement/MASTER_SECRET";
 }

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

@@ -16,6 +16,7 @@ public interface TorConstants {
 	String PREF_TOR_NETWORK = "network2";
 	String PREF_TOR_PORT = "port";
 	String PREF_TOR_MOBILE = "useMobileData";
+	String PREF_TOR_ONLY_WHEN_CHARGING = "onlyWhenCharging";
 
 	int PREF_TOR_NETWORK_AUTOMATIC = 0;
 	int PREF_TOR_NETWORK_WITHOUT_BRIDGES = 1;

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

@@ -35,9 +35,4 @@ public interface SyncConstants {
 	 * The maximum number of message IDs in an ack, offer or request record.
 	 */
 	int MAX_MESSAGE_IDS = MAX_RECORD_PAYLOAD_BYTES / UniqueId.LENGTH;
-
-	/**
-	 * The maximum length of a message block in bytes.
-	 */
-	int MAX_BLOCK_LENGTH = 32 * 2014; // 32 KiB
 }

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

@@ -0,0 +1,57 @@
+package org.briarproject.bramble.api.transport;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.TransportId;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * Abstract superclass for {@link TransportKeys} and {@link HandshakeKeys}.
+ */
+@Immutable
+@NotNullByDefault
+public abstract class AbstractTransportKeys {
+
+	private final TransportId transportId;
+	private final IncomingKeys inPrev, inCurr, inNext;
+	private final OutgoingKeys outCurr;
+
+	AbstractTransportKeys(TransportId transportId, IncomingKeys inPrev,
+			IncomingKeys inCurr, IncomingKeys inNext, OutgoingKeys outCurr) {
+		if (inPrev.getTimePeriod() != outCurr.getTimePeriod() - 1)
+			throw new IllegalArgumentException();
+		if (inCurr.getTimePeriod() != outCurr.getTimePeriod())
+			throw new IllegalArgumentException();
+		if (inNext.getTimePeriod() != outCurr.getTimePeriod() + 1)
+			throw new IllegalArgumentException();
+		this.transportId = transportId;
+		this.inPrev = inPrev;
+		this.inCurr = inCurr;
+		this.inNext = inNext;
+		this.outCurr = outCurr;
+	}
+
+	public TransportId getTransportId() {
+		return transportId;
+	}
+
+	public IncomingKeys getPreviousIncomingKeys() {
+		return inPrev;
+	}
+
+	public IncomingKeys getCurrentIncomingKeys() {
+		return inCurr;
+	}
+
+	public IncomingKeys getNextIncomingKeys() {
+		return inNext;
+	}
+
+	public OutgoingKeys getCurrentOutgoingKeys() {
+		return outCurr;
+	}
+
+	public long getTimePeriod() {
+		return outCurr.getTimePeriod();
+	}
+}

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

@@ -0,0 +1,70 @@
+package org.briarproject.bramble.api.transport;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.PendingContactId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * A set of keys for handshaking with a given contact or pending contact over a
+ * given transport. Unlike a {@link TransportKeySet} these keys do not provide
+ * forward secrecy.
+ */
+@Immutable
+@NotNullByDefault
+public class HandshakeKeySet {
+
+	private final HandshakeKeySetId keySetId;
+	@Nullable
+	private final ContactId contactId;
+	@Nullable
+	private final PendingContactId pendingContactId;
+	private final HandshakeKeys keys;
+
+	public HandshakeKeySet(HandshakeKeySetId keySetId, ContactId contactId,
+			HandshakeKeys keys) {
+		this.keySetId = keySetId;
+		this.contactId = contactId;
+		this.keys = keys;
+		pendingContactId = null;
+	}
+
+	public HandshakeKeySet(HandshakeKeySetId keySetId,
+			PendingContactId pendingContactId, HandshakeKeys keys) {
+		this.keySetId = keySetId;
+		this.pendingContactId = pendingContactId;
+		this.keys = keys;
+		contactId = null;
+	}
+
+	public HandshakeKeySetId getKeySetId() {
+		return keySetId;
+	}
+
+	@Nullable
+	public ContactId getContactId() {
+		return contactId;
+	}
+
+	@Nullable
+	public PendingContactId getPendingContactId() {
+		return pendingContactId;
+	}
+
+	public HandshakeKeys getKeys() {
+		return keys;
+	}
+
+	@Override
+	public int hashCode() {
+		return keySetId.hashCode();
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		return o instanceof HandshakeKeySet &&
+				keySetId.equals(((HandshakeKeySet) o).keySetId);
+	}
+}

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

@@ -0,0 +1,36 @@
+package org.briarproject.bramble.api.transport;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * Type-safe wrapper for an integer that uniquely identifies a
+ * {@link HandshakeKeySet set of handshake keys} within the scope of the local
+ * device.
+ */
+@Immutable
+@NotNullByDefault
+public class HandshakeKeySetId {
+
+	private final int id;
+
+	public HandshakeKeySetId(int id) {
+		this.id = id;
+	}
+
+	public int getInt() {
+		return id;
+	}
+
+	@Override
+	public int hashCode() {
+		return id;
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		return o instanceof HandshakeKeySetId &&
+				id == ((HandshakeKeySetId) o).id;
+	}
+}

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

@@ -0,0 +1,36 @@
+package org.briarproject.bramble.api.transport;
+
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.TransportId;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * Keys for handshaking with a given contact or pending contact over a given
+ * transport. Unlike {@link TransportKeys} these keys do not provide forward
+ * secrecy.
+ */
+@Immutable
+@NotNullByDefault
+public class HandshakeKeys extends AbstractTransportKeys {
+
+	private final SecretKey rootKey;
+	private final boolean alice;
+
+	public HandshakeKeys(TransportId transportId, IncomingKeys inPrev,
+			IncomingKeys inCurr, IncomingKeys inNext, OutgoingKeys outCurr,
+			SecretKey rootKey, boolean alice) {
+		super(transportId, inPrev, inCurr, inNext, outCurr);
+		this.rootKey = rootKey;
+		this.alice = alice;
+	}
+
+	public SecretKey getRootKey() {
+		return rootKey;
+	}
+
+	public boolean isAlice() {
+		return alice;
+	}
+}

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

@@ -1,30 +1,35 @@
 package org.briarproject.bramble.api.transport;
 
 import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
 
 import static org.briarproject.bramble.api.transport.TransportConstants.REORDERING_WINDOW_SIZE;
 
 /**
  * Contains transport keys for receiving streams from a given contact over a
- * given transport in a given rotation period.
+ * given transport in a given time period.
  */
+@Immutable
+@NotNullByDefault
 public class IncomingKeys {
 
 	private final SecretKey tagKey, headerKey;
-	private final long rotationPeriod, windowBase;
+	private final long timePeriod, windowBase;
 	private final byte[] windowBitmap;
 
 	public IncomingKeys(SecretKey tagKey, SecretKey headerKey,
-			long rotationPeriod) {
-		this(tagKey, headerKey, rotationPeriod, 0,
+			long timePeriod) {
+		this(tagKey, headerKey, timePeriod, 0,
 				new byte[REORDERING_WINDOW_SIZE / 8]);
 	}
 
 	public IncomingKeys(SecretKey tagKey, SecretKey headerKey,
-			long rotationPeriod, long windowBase, byte[] windowBitmap) {
+			long timePeriod, long windowBase, byte[] windowBitmap) {
 		this.tagKey = tagKey;
 		this.headerKey = headerKey;
-		this.rotationPeriod = rotationPeriod;
+		this.timePeriod = timePeriod;
 		this.windowBase = windowBase;
 		this.windowBitmap = windowBitmap;
 	}
@@ -37,8 +42,8 @@ public class IncomingKeys {
 		return headerKey;
 	}
 
-	public long getRotationPeriod() {
-		return rotationPeriod;
+	public long getTimePeriod() {
+		return timePeriod;
 	}
 
 	public long getWindowBase() {

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

@@ -27,14 +27,14 @@ public interface KeyManager {
 	 * @param alice true if the local party is Alice
 	 * @param active whether the derived keys can be used for outgoing streams
 	 */
-	Map<TransportId, KeySetId> addContact(Transaction txn, ContactId c,
-			SecretKey master, long timestamp, boolean alice, boolean active)
+	Map<TransportId, TransportKeySetId> addContact(Transaction txn, ContactId c,
+			SecretKey rootKey, long timestamp, boolean alice, boolean active)
 			throws DbException;
 
 	/**
 	 * Marks the given transport keys as usable for outgoing streams.
 	 */
-	void activateKeys(Transaction txn, Map<TransportId, KeySetId> keys)
+	void activateKeys(Transaction txn, Map<TransportId, TransportKeySetId> keys)
 			throws DbException;
 
 	/**

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

@@ -1,47 +0,0 @@
-package org.briarproject.bramble.api.transport;
-
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-/**
- * A set of transport keys for communicating with a contact.
- */
-@Immutable
-@NotNullByDefault
-public class KeySet {
-
-	private final KeySetId keySetId;
-	private final ContactId contactId;
-	private final TransportKeys transportKeys;
-
-	public KeySet(KeySetId keySetId, ContactId contactId,
-			TransportKeys transportKeys) {
-		this.keySetId = keySetId;
-		this.contactId = contactId;
-		this.transportKeys = transportKeys;
-	}
-
-	public KeySetId getKeySetId() {
-		return keySetId;
-	}
-
-	public ContactId getContactId() {
-		return contactId;
-	}
-
-	public TransportKeys getTransportKeys() {
-		return transportKeys;
-	}
-
-	@Override
-	public int hashCode() {
-		return keySetId.hashCode();
-	}
-
-	@Override
-	public boolean equals(Object o) {
-		return o instanceof KeySet && keySetId.equals(((KeySet) o).keySetId);
-	}
-}

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

@@ -1,27 +1,32 @@
 package org.briarproject.bramble.api.transport;
 
 import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
 
 /**
  * Contains transport keys for sending streams to a given contact over a given
- * transport in a given rotation period.
+ * transport in a given time period.
  */
+@Immutable
+@NotNullByDefault
 public class OutgoingKeys {
 
 	private final SecretKey tagKey, headerKey;
-	private final long rotationPeriod, streamCounter;
+	private final long timePeriod, streamCounter;
 	private final boolean active;
 
 	public OutgoingKeys(SecretKey tagKey, SecretKey headerKey,
-			long rotationPeriod, boolean active) {
-		this(tagKey, headerKey, rotationPeriod, 0, active);
+			long timePeriod, boolean active) {
+		this(tagKey, headerKey, timePeriod, 0, active);
 	}
 
 	public OutgoingKeys(SecretKey tagKey, SecretKey headerKey,
-			long rotationPeriod, long streamCounter, boolean active) {
+			long timePeriod, long streamCounter, boolean active) {
 		this.tagKey = tagKey;
 		this.headerKey = headerKey;
-		this.rotationPeriod = rotationPeriod;
+		this.timePeriod = timePeriod;
 		this.streamCounter = streamCounter;
 		this.active = active;
 	}
@@ -34,8 +39,8 @@ public class OutgoingKeys {
 		return headerKey;
 	}
 
-	public long getRotationPeriod() {
-		return rotationPeriod;
+	public long getTimePeriod() {
+		return timePeriod;
 	}
 
 	public long getStreamCounter() {

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

@@ -2,8 +2,13 @@ package org.briarproject.bramble.api.transport;
 
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
 public class StreamContext {
 
 	private final ContactId contactId;

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

@@ -82,30 +82,58 @@ public interface TransportConstants {
 	int REORDERING_WINDOW_SIZE = 32;
 
 	/**
-	 * Label for deriving Alice's initial tag key from the master secret.
+	 * Label for deriving Alice's initial tag key from the root key in
+	 * rotation mode.
 	 */
 	String ALICE_TAG_LABEL = "org.briarproject.bramble.transport/ALICE_TAG_KEY";
 
 	/**
-	 * Label for deriving Bob's initial tag key from the master secret.
+	 * Label for deriving Bob's initial tag key from the root key in rotation
+	 * mode.
 	 */
 	String BOB_TAG_LABEL = "org.briarproject.bramble.transport/BOB_TAG_KEY";
 
 	/**
-	 * Label for deriving Alice's initial header key from the master secret.
+	 * Label for deriving Alice's initial header key from the root key in
+	 * rotation mode.
 	 */
 	String ALICE_HEADER_LABEL =
 			"org.briarproject.bramble.transport/ALICE_HEADER_KEY";
 
 	/**
-	 * Label for deriving Bob's initial header key from the master secret.
+	 * Label for deriving Bob's initial header key from the root key in
+	 * rotation mode.
 	 */
 	String BOB_HEADER_LABEL =
 			"org.briarproject.bramble.transport/BOB_HEADER_KEY";
 
 	/**
-	 * Label for deriving the next period's key in key rotation.
+	 * Label for deriving the next period's key in rotation mode.
 	 */
 	String ROTATE_LABEL = "org.briarproject.bramble.transport/ROTATE";
 
+	/**
+	 * Label for deriving Alice's tag key from the root key in handshake mode.
+	 */
+	String ALICE_HANDSHAKE_TAG_LABEL =
+			"org.briarproject.bramble.transport/ALICE_HANDSHAKE_TAG_KEY";
+
+	/**
+	 * Label for deriving Bob's tag key from the root key in handshake mode.
+	 */
+	String BOB_HANDSHAKE_TAG_LABEL =
+			"org.briarproject.bramble.transport/BOB_HANDSHAKE_TAG_KEY";
+
+	/**
+	 * Label for deriving Alice's header key from the root key in handshake
+	 * mode.
+	 */
+	String ALICE_HANDSHAKE_HEADER_LABEL =
+			"org.briarproject.bramble.transport/ALICE_HANDSHAKE_HEADER_KEY";
+
+	/**
+	 * Label for deriving Bob's header key from the root key in handshake mode.
+	 */
+	String BOB_HANDSHAKE_HEADER_LABEL =
+			"org.briarproject.bramble.transport/BOB_HANDSHAKE_HEADER_KEY";
 }

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

@@ -0,0 +1,49 @@
+package org.briarproject.bramble.api.transport;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * A set of keys for communicating with a given contact over a given transport.
+ * Unlike a {@link HandshakeKeySet} these keys provide forward secrecy.
+ */
+@Immutable
+@NotNullByDefault
+public class TransportKeySet {
+
+	private final TransportKeySetId keySetId;
+	private final ContactId contactId;
+	private final TransportKeys keys;
+
+	public TransportKeySet(TransportKeySetId keySetId, ContactId contactId,
+			TransportKeys keys) {
+		this.keySetId = keySetId;
+		this.contactId = contactId;
+		this.keys = keys;
+	}
+
+	public TransportKeySetId getKeySetId() {
+		return keySetId;
+	}
+
+	public ContactId getContactId() {
+		return contactId;
+	}
+
+	public TransportKeys getKeys() {
+		return keys;
+	}
+
+	@Override
+	public int hashCode() {
+		return keySetId.hashCode();
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		return o instanceof TransportKeySet &&
+				keySetId.equals(((TransportKeySet) o).keySetId);
+	}
+}

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

@@ -5,18 +5,19 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import javax.annotation.concurrent.Immutable;
 
 /**
- * Type-safe wrapper for an integer that uniquely identifies a set of transport
- * keys within the scope of the local device.
+ * Type-safe wrapper for an integer that uniquely identifies a
+ * {@link TransportKeySet set of transport keys} within the scope of the local
+ * device.
  * <p/>
  * Key sets created on a given device must have increasing identifiers.
  */
 @Immutable
 @NotNullByDefault
-public class KeySetId {
+public class TransportKeySetId {
 
 	private final int id;
 
-	public KeySetId(int id) {
+	public TransportKeySetId(int id) {
 		this.id = id;
 	}
 
@@ -31,6 +32,7 @@ public class KeySetId {
 
 	@Override
 	public boolean equals(Object o) {
-		return o instanceof KeySetId && id == ((KeySetId) o).id;
+		return o instanceof TransportKeySetId &&
+				id == ((TransportKeySetId) o).id;
 	}
 }

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

@@ -1,52 +1,20 @@
 package org.briarproject.bramble.api.transport;
 
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 
-/**
- * Keys for communicating with a given contact over a given transport.
- */
-public class TransportKeys {
+import javax.annotation.concurrent.Immutable;
 
-	private final TransportId transportId;
-	private final IncomingKeys inPrev, inCurr, inNext;
-	private final OutgoingKeys outCurr;
+/**
+ * Keys for communicating with a given contact over a given transport. Unlike
+ * {@link HandshakeKeys} these keys provide forward secrecy.
+ */
+@Immutable
+@NotNullByDefault
+public class TransportKeys extends AbstractTransportKeys {
 
 	public TransportKeys(TransportId transportId, IncomingKeys inPrev,
 			IncomingKeys inCurr, IncomingKeys inNext, OutgoingKeys outCurr) {
-		if (inPrev.getRotationPeriod() != inCurr.getRotationPeriod() - 1)
-			throw new IllegalArgumentException();
-		if (inNext.getRotationPeriod() != inCurr.getRotationPeriod() + 1)
-			throw new IllegalArgumentException();
-		if (outCurr.getRotationPeriod() != inCurr.getRotationPeriod())
-			throw new IllegalArgumentException();
-		this.transportId = transportId;
-		this.inPrev = inPrev;
-		this.inCurr = inCurr;
-		this.inNext = inNext;
-		this.outCurr = outCurr;
-	}
-
-	public TransportId getTransportId() {
-		return transportId;
-	}
-
-	public IncomingKeys getPreviousIncomingKeys() {
-		return inPrev;
-	}
-
-	public IncomingKeys getCurrentIncomingKeys() {
-		return inCurr;
-	}
-
-	public IncomingKeys getNextIncomingKeys() {
-		return inNext;
-	}
-
-	public OutgoingKeys getCurrentOutgoingKeys() {
-		return outCurr;
-	}
-
-	public long getRotationPeriod() {
-		return outCurr.getRotationPeriod();
+		super(transportId, inPrev, inCurr, inNext, outCurr);
 	}
 }

bramble-api/src/main/java/org/briarproject/bramble/api/versioning/ClientVersioningManager.java

@@ -38,6 +38,13 @@ public interface ClientVersioningManager {
 	Visibility getClientVisibility(Transaction txn, ContactId contactId,
 			ClientId clientId, int majorVersion) throws DbException;
 
+	/**
+	 * Returns the minor version of the given client that is supported by the
+	 * given contact, or -1 if the contact does not support the client.
+	 */
+	int getClientMinorVersion(Transaction txn, ContactId contactId,
+			ClientId clientId, int majorVersion) throws DbException;
+
 	interface ClientVersioningHook {
 
 		void onClientVisibilityChanging(Transaction txn, Contact c,

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

@@ -1,6 +1,10 @@
 package org.briarproject.bramble.test;
 
 import org.briarproject.bramble.api.UniqueId;
+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.SecretKey;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
@@ -25,6 +29,7 @@ import java.util.Random;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import static java.util.Arrays.asList;
+import static org.briarproject.bramble.api.contact.PendingContactState.WAITING_FOR_CONNECTION;
 import static org.briarproject.bramble.api.identity.Author.FORMAT_VERSION;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
@@ -41,6 +46,7 @@ public class TestUtils {
 			new AtomicInteger((int) (Math.random() * 1000 * 1000));
 	private static final Random random = new Random();
 	private static final long timestamp = System.currentTimeMillis();
+	private static final AtomicInteger nextContactId = new AtomicInteger(1);
 
 	public static File getTestDirectory() {
 		int name = nextTestDir.getAndIncrement();
@@ -140,6 +146,35 @@ public class TestUtils {
 		return new Message(id, groupId, timestamp, body);
 	}
 
+	public static PendingContact getPendingContact() {
+		return getPendingContact(1 + random.nextInt(MAX_AUTHOR_NAME_LENGTH));
+	}
+
+	public static PendingContact getPendingContact(int nameLength) {
+		PendingContactId id = new PendingContactId(getRandomId());
+		byte[] publicKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
+		String alias = getRandomString(nameLength);
+		return new PendingContact(id, publicKey, alias, WAITING_FOR_CONNECTION,
+				timestamp);
+	}
+
+	public static ContactId getContactId() {
+		return new ContactId(nextContactId.getAndIncrement());
+	}
+
+	public static Contact getContact() {
+		return getContact(getAuthor(), random.nextBoolean());
+	}
+
+	public static Contact getContact(Author a, boolean verified) {
+		return getContact(getContactId(), a, verified);
+	}
+
+	public static Contact getContact(ContactId c, Author a, boolean verified) {
+		return new Contact(c, a, getRandomString(MAX_AUTHOR_NAME_LENGTH),
+				getRandomBytes(MAX_PUBLIC_KEY_LENGTH), verified);
+	}
+
 	public static double getMedian(Collection<? extends Number> samples) {
 		int size = samples.size();
 		if (size == 0) throw new IllegalArgumentException();

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

@@ -9,7 +9,6 @@ import org.briarproject.bramble.db.DatabaseExecutorModule;
 import org.briarproject.bramble.db.DatabaseModule;
 import org.briarproject.bramble.event.EventModule;
 import org.briarproject.bramble.identity.IdentityModule;
-import org.briarproject.bramble.io.IoModule;
 import org.briarproject.bramble.keyagreement.KeyAgreementModule;
 import org.briarproject.bramble.lifecycle.LifecycleModule;
 import org.briarproject.bramble.plugin.PluginModule;
@@ -37,7 +36,6 @@ import dagger.Module;
 		DatabaseExecutorModule.class,
 		EventModule.class,
 		IdentityModule.class,
-		IoModule.class,
 		KeyAgreementModule.class,
 		LifecycleModule.class,
 		PluginModule.class,

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

@@ -39,8 +39,7 @@ class ContactGroupFactoryImpl implements ContactGroupFactory {
 
 	@Override
 	public Group createContactGroup(ClientId clientId, int majorVersion,
-			Contact contact) {
-		AuthorId local = contact.getLocalAuthorId();
+			Contact contact, AuthorId local) {
 		AuthorId remote = contact.getAuthor().getId();
 		byte[] descriptor = createGroupDescriptor(local, remote);
 		return groupFactory.createGroup(clientId, majorVersion, descriptor);

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

@@ -2,10 +2,11 @@ package org.briarproject.bramble.contact;
 
 import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.api.client.ClientHelper;
-import org.briarproject.bramble.api.contact.ContactExchangeListener;
 import org.briarproject.bramble.api.contact.ContactExchangeTask;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
+import org.briarproject.bramble.api.contact.event.ContactExchangeFailedEvent;
+import org.briarproject.bramble.api.contact.event.ContactExchangeSucceededEvent;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.data.BdfDictionary;
@@ -13,6 +14,7 @@ import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.db.ContactExistsException;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
@@ -63,6 +65,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 	private final ClientHelper clientHelper;
 	private final RecordReaderFactory recordReaderFactory;
 	private final RecordWriterFactory recordWriterFactory;
+	private final EventBus eventBus;
 	private final Clock clock;
 	private final ConnectionManager connectionManager;
 	private final ContactManager contactManager;
@@ -71,18 +74,18 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 	private final StreamReaderFactory streamReaderFactory;
 	private final StreamWriterFactory streamWriterFactory;
 
-	private volatile ContactExchangeListener listener;
 	private volatile LocalAuthor localAuthor;
 	private volatile DuplexTransportConnection conn;
 	private volatile TransportId transportId;
-	private volatile SecretKey masterSecret;
+	private volatile SecretKey masterKey;
 	private volatile boolean alice;
 
 	@Inject
 	ContactExchangeTaskImpl(DatabaseComponent db, ClientHelper clientHelper,
 			RecordReaderFactory recordReaderFactory,
-			RecordWriterFactory recordWriterFactory, Clock clock,
-			ConnectionManager connectionManager, ContactManager contactManager,
+			RecordWriterFactory recordWriterFactory, EventBus eventBus,
+			Clock clock, ConnectionManager connectionManager,
+			ContactManager contactManager,
 			TransportPropertyManager transportPropertyManager,
 			CryptoComponent crypto, StreamReaderFactory streamReaderFactory,
 			StreamWriterFactory streamWriterFactory) {
@@ -90,6 +93,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		this.clientHelper = clientHelper;
 		this.recordReaderFactory = recordReaderFactory;
 		this.recordWriterFactory = recordWriterFactory;
+		this.eventBus = eventBus;
 		this.clock = clock;
 		this.connectionManager = connectionManager;
 		this.contactManager = contactManager;
@@ -100,15 +104,13 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 	}
 
 	@Override
-	public void startExchange(ContactExchangeListener listener,
-			LocalAuthor localAuthor, SecretKey masterSecret,
+	public void startExchange(LocalAuthor localAuthor, SecretKey masterKey,
 			DuplexTransportConnection conn, TransportId transportId,
 			boolean alice) {
-		this.listener = listener;
 		this.localAuthor = localAuthor;
 		this.conn = conn;
 		this.transportId = transportId;
-		this.masterSecret = masterSecret;
+		this.masterKey = masterKey;
 		this.alice = alice;
 		start();
 	}
@@ -123,8 +125,8 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 			out = conn.getWriter().getOutputStream();
 		} catch (IOException e) {
 			logException(LOG, WARNING, e);
-			listener.contactExchangeFailed();
 			tryToClose(conn);
+			eventBus.broadcast(new ContactExchangeFailedEvent());
 			return;
 		}
 
@@ -134,15 +136,15 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 			localProperties = transportPropertyManager.getLocalProperties();
 		} catch (DbException e) {
 			logException(LOG, WARNING, e);
-			listener.contactExchangeFailed();
+			eventBus.broadcast(new ContactExchangeFailedEvent());
 			tryToClose(conn);
 			return;
 		}
 
 		// Derive the header keys for the transport streams
-		SecretKey aliceHeaderKey = crypto.deriveKey(ALICE_KEY_LABEL,
-				masterSecret, new byte[] {PROTOCOL_VERSION});
-		SecretKey bobHeaderKey = crypto.deriveKey(BOB_KEY_LABEL, masterSecret,
+		SecretKey aliceHeaderKey = crypto.deriveKey(ALICE_KEY_LABEL, masterKey,
+				new byte[] {PROTOCOL_VERSION});
+		SecretKey bobHeaderKey = crypto.deriveKey(BOB_KEY_LABEL, masterKey,
 				new byte[] {PROTOCOL_VERSION});
 
 		// Create the readers
@@ -161,9 +163,9 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 						.createRecordWriter(streamWriter.getOutputStream());
 
 		// Derive the nonces to be signed
-		byte[] aliceNonce = crypto.mac(ALICE_NONCE_LABEL, masterSecret,
+		byte[] aliceNonce = crypto.mac(ALICE_NONCE_LABEL, masterKey,
 				new byte[] {PROTOCOL_VERSION});
-		byte[] bobNonce = crypto.mac(BOB_NONCE_LABEL, masterSecret,
+		byte[] bobNonce = crypto.mac(BOB_NONCE_LABEL, masterKey,
 				new byte[] {PROTOCOL_VERSION});
 		byte[] localNonce = alice ? aliceNonce : bobNonce;
 		byte[] remoteNonce = alice ? bobNonce : aliceNonce;
@@ -196,7 +198,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 			}
 		} catch (IOException e) {
 			logException(LOG, WARNING, e);
-			listener.contactExchangeFailed();
+			eventBus.broadcast(new ContactExchangeFailedEvent());
 			tryToClose(conn);
 			return;
 		}
@@ -204,7 +206,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		// Verify the contact's signature
 		if (!verify(remoteInfo.author, remoteNonce, remoteInfo.signature)) {
 			LOG.warning("Invalid signature");
-			listener.contactExchangeFailed();
+			eventBus.broadcast(new ContactExchangeFailedEvent());
 			tryToClose(conn);
 			return;
 		}
@@ -221,15 +223,17 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 					conn);
 			// Pseudonym exchange succeeded
 			LOG.info("Pseudonym exchange succeeded");
-			listener.contactExchangeSucceeded(remoteInfo.author);
+			eventBus.broadcast(
+					new ContactExchangeSucceededEvent(remoteInfo.author));
 		} catch (ContactExistsException e) {
 			logException(LOG, WARNING, e);
 			tryToClose(conn);
-			listener.duplicateContact(remoteInfo.author);
+			eventBus.broadcast(
+					new ContactExchangeFailedEvent(remoteInfo.author));
 		} catch (DbException e) {
 			logException(LOG, WARNING, e);
 			tryToClose(conn);
-			listener.contactExchangeFailed();
+			eventBus.broadcast(new ContactExchangeFailedEvent());
 		}
 	}
 
@@ -289,8 +293,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 			throws DbException {
 		return db.transactionWithResult(false, txn -> {
 			ContactId contactId = contactManager.addContact(txn, remoteAuthor,
-					localAuthor.getId(), masterSecret, timestamp, alice,
-					true, true);
+					masterKey, timestamp, alice, true, true);
 			transportPropertyManager.addRemoteProperties(txn, contactId,
 					remoteProperties);
 			return contactId;

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

@@ -3,10 +3,11 @@ package org.briarproject.bramble.contact;
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
+import org.briarproject.bramble.api.contact.PendingContact;
+import org.briarproject.bramble.api.contact.PendingContactId;
 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.NoSuchContactException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
@@ -16,16 +17,20 @@ import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.transport.KeyManager;
 
-import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import java.util.Random;
 import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.regex.Pattern;
 
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 import javax.inject.Inject;
 
+import static java.util.Collections.emptyList;
+import static org.briarproject.bramble.api.contact.PendingContactState.WAITING_FOR_CONNECTION;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorInfo.Status.OURSELVES;
 import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNKNOWN;
 import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNVERIFIED;
@@ -36,6 +41,12 @@ import static org.briarproject.bramble.util.StringUtils.toUtf8;
 @NotNullByDefault
 class ContactManagerImpl implements ContactManager {
 
+	private static final int LINK_LENGTH = 64;
+	private static final String REMOTE_CONTACT_LINK =
+			"briar://" + getRandomBase32String(LINK_LENGTH);
+	private static final Pattern LINK_REGEX =
+			Pattern.compile("(briar://)?([a-z2-7]{" + LINK_LENGTH + "})");
+
 	private final DatabaseComponent db;
 	private final KeyManager keyManager;
 	private final IdentityManager identityManager;
@@ -56,66 +67,94 @@ class ContactManagerImpl implements ContactManager {
 	}
 
 	@Override
-	public ContactId addContact(Transaction txn, Author remote, AuthorId local,
-			SecretKey master, long timestamp, boolean alice, boolean verified,
-			boolean active) throws DbException {
-		ContactId c = db.addContact(txn, remote, local, verified, active);
-		keyManager.addContact(txn, c, master, timestamp, alice, active);
-		Contact contact = db.getContact(txn, c);
-		for (ContactHook hook : hooks) hook.addingContact(txn, contact);
-		return c;
-	}
-
-	@Override
-	public ContactId addContact(Transaction txn, Author remote, AuthorId local,
-			boolean verified, boolean active) throws DbException {
-		ContactId c = db.addContact(txn, remote, local, verified, active);
-		Contact contact = db.getContact(txn, c);
-		for (ContactHook hook : hooks) hook.addingContact(txn, contact);
-		return c;
-	}
-
-	@Override
-	public ContactId addContact(Author remote, AuthorId local, SecretKey master,
+	public ContactId addContact(Transaction txn, Author a, SecretKey rootKey,
 			long timestamp, boolean alice, boolean verified, boolean active)
 			throws DbException {
+		ContactId c = db.addContact(txn, a, verified);
+		keyManager.addContact(txn, c, rootKey, timestamp, alice, active);
+		Contact contact = db.getContact(txn, c);
+		for (ContactHook hook : hooks) hook.addingContact(txn, contact);
+		return c;
+	}
+
+	@Override
+	public ContactId addContact(Transaction txn, Author a, boolean verified)
+			throws DbException {
+		ContactId c = db.addContact(txn, a, verified);
+		Contact contact = db.getContact(txn, c);
+		for (ContactHook hook : hooks) hook.addingContact(txn, contact);
+		return c;
+	}
+
+	@Override
+	public ContactId addContact(Author a, SecretKey rootKey, long timestamp,
+			boolean alice, boolean verified, boolean active)
+			throws DbException {
 		return db.transactionWithResult(false, txn ->
-				addContact(txn, remote, local, master, timestamp, alice,
+				addContact(txn, a, rootKey, timestamp, alice,
 						verified, active));
 	}
 
+	@Override
+	public String getRemoteContactLink() {
+		// TODO replace with real implementation
+		return REMOTE_CONTACT_LINK;
+	}
+
+	@SuppressWarnings("SameParameterValue")
+	private static String getRandomBase32String(int length) {
+		Random random = new Random();
+		char[] c = new char[length];
+		for (int i = 0; i < length; i++) {
+			int character = random.nextInt(32);
+			if (character < 26) c[i] = (char) ('a' + character);
+			else c[i] = (char) ('2' + (character - 26));
+		}
+		return new String(c);
+	}
+
+	@Override
+	public boolean isValidRemoteContactLink(String link) {
+		return LINK_REGEX.matcher(link).matches();
+	}
+
+	@Override
+	public PendingContact addRemoteContactRequest(String link, String alias) {
+		// TODO replace with real implementation
+		PendingContactId id = new PendingContactId(link.getBytes());
+		return new PendingContact(id, new byte[MAX_PUBLIC_KEY_LENGTH], alias,
+				WAITING_FOR_CONNECTION, System.currentTimeMillis());
+	}
+
+	@Override
+	public Collection<PendingContact> getPendingContacts() {
+		// TODO replace with real implementation
+		return emptyList();
+	}
+
+	@Override
+	public void removePendingContact(PendingContact pendingContact) {
+		// TODO replace with real implementation
+	}
+
 	@Override
 	public Contact getContact(ContactId c) throws DbException {
 		return db.transactionWithResult(true, txn -> db.getContact(txn, c));
 	}
 
 	@Override
-	public Contact getContact(AuthorId remoteAuthorId, AuthorId localAuthorId)
-			throws DbException {
-		return db.transactionWithResult(true, txn ->
-				getContact(txn, remoteAuthorId, localAuthorId));
+	public Contact getContact(AuthorId a) throws DbException {
+		return db.transactionWithResult(true, txn -> getContact(txn, a));
 	}
 
 	@Override
-	public Contact getContact(Transaction txn, AuthorId remoteAuthorId,
-			AuthorId localAuthorId) throws DbException {
-		Collection<Contact> contacts =
-				db.getContactsByAuthorId(txn, remoteAuthorId);
-		for (Contact c : contacts) {
-			if (c.getLocalAuthorId().equals(localAuthorId)) {
-				return c;
-			}
-		}
-		throw new NoSuchContactException();
+	public Contact getContact(Transaction txn, AuthorId a) throws DbException {
+		return db.getContact(txn, a);
 	}
 
 	@Override
-	public Collection<Contact> getActiveContacts() throws DbException {
-		Collection<Contact> contacts =
-				db.transactionWithResult(true, db::getContacts);
-		List<Contact> active = new ArrayList<>(contacts.size());
-		for (Contact c : contacts) if (c.isActive()) active.add(c);
-		return active;
+	public Collection<Contact> getContacts() throws DbException {
+		return db.transactionWithResult(true, db::getContacts);
 	}
 
 	@Override
@@ -123,12 +162,6 @@ class ContactManagerImpl implements ContactManager {
 		db.transaction(false, txn -> removeContact(txn, c));
 	}
 
-	@Override
-	public void setContactActive(Transaction txn, ContactId c, boolean active)
-			throws DbException {
-		db.setContactActive(txn, c, active);
-	}
-
 	@Override
 	public void setContactAlias(Transaction txn, ContactId c,
 			@Nullable String alias) throws DbException {
@@ -147,16 +180,14 @@ class ContactManagerImpl implements ContactManager {
 	}
 
 	@Override
-	public boolean contactExists(Transaction txn, AuthorId remoteAuthorId,
-			AuthorId localAuthorId) throws DbException {
-		return db.containsContact(txn, remoteAuthorId, localAuthorId);
+	public boolean contactExists(Transaction txn, AuthorId a)
+			throws DbException {
+		return db.containsContact(txn, a);
 	}
 
 	@Override
-	public boolean contactExists(AuthorId remoteAuthorId,
-			AuthorId localAuthorId) throws DbException {
-		return db.transactionWithResult(true, txn ->
-				contactExists(txn, remoteAuthorId, localAuthorId));
+	public boolean contactExists(AuthorId a) throws DbException {
+		return db.transactionWithResult(true, txn -> contactExists(txn, a));
 	}
 
 	@Override
@@ -178,12 +209,12 @@ class ContactManagerImpl implements ContactManager {
 		LocalAuthor localAuthor = identityManager.getLocalAuthor(txn);
 		if (localAuthor.getId().equals(authorId))
 			return new AuthorInfo(OURSELVES);
-		Collection<Contact> contacts = db.getContactsByAuthorId(txn, authorId);
-		if (contacts.isEmpty()) return new AuthorInfo(UNKNOWN);
-		if (contacts.size() > 1) throw new AssertionError();
-		Contact c = contacts.iterator().next();
-		if (c.isVerified()) return new AuthorInfo(VERIFIED, c.getAlias());
-		else return new AuthorInfo(UNVERIFIED, c.getAlias());
+		if (db.containsContact(txn, authorId)) {
+			Contact c = db.getContact(txn, authorId);
+			if (c.isVerified()) return new AuthorInfo(VERIFIED, c.getAlias());
+			else return new AuthorInfo(UNVERIFIED, c.getAlias());
+		}
+		return new AuthorInfo(UNKNOWN);
 	}
 
 }

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

@@ -4,18 +4,22 @@ import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.crypto.TransportCrypto;
 import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.transport.HandshakeKeys;
 import org.briarproject.bramble.api.transport.IncomingKeys;
 import org.briarproject.bramble.api.transport.OutgoingKeys;
 import org.briarproject.bramble.api.transport.TransportKeys;
-import org.briarproject.bramble.util.ByteUtils;
-import org.briarproject.bramble.util.StringUtils;
 import org.spongycastle.crypto.Digest;
 import org.spongycastle.crypto.digests.Blake2bDigest;
 
 import javax.inject.Inject;
 
+import static java.lang.System.arraycopy;
+import static org.briarproject.bramble.api.transport.TransportConstants.ALICE_HANDSHAKE_HEADER_LABEL;
+import static org.briarproject.bramble.api.transport.TransportConstants.ALICE_HANDSHAKE_TAG_LABEL;
 import static org.briarproject.bramble.api.transport.TransportConstants.ALICE_HEADER_LABEL;
 import static org.briarproject.bramble.api.transport.TransportConstants.ALICE_TAG_LABEL;
+import static org.briarproject.bramble.api.transport.TransportConstants.BOB_HANDSHAKE_HEADER_LABEL;
+import static org.briarproject.bramble.api.transport.TransportConstants.BOB_HANDSHAKE_TAG_LABEL;
 import static org.briarproject.bramble.api.transport.TransportConstants.BOB_HEADER_LABEL;
 import static org.briarproject.bramble.api.transport.TransportConstants.BOB_TAG_LABEL;
 import static org.briarproject.bramble.api.transport.TransportConstants.ROTATE_LABEL;
@@ -24,6 +28,9 @@ import static org.briarproject.bramble.util.ByteUtils.INT_16_BYTES;
 import static org.briarproject.bramble.util.ByteUtils.INT_64_BYTES;
 import static org.briarproject.bramble.util.ByteUtils.MAX_16_BIT_UNSIGNED;
 import static org.briarproject.bramble.util.ByteUtils.MAX_32_BIT_UNSIGNED;
+import static org.briarproject.bramble.util.ByteUtils.writeUint16;
+import static org.briarproject.bramble.util.ByteUtils.writeUint64;
+import static org.briarproject.bramble.util.StringUtils.toUtf8;
 
 class TransportCryptoImpl implements TransportCrypto {
 
@@ -36,45 +43,44 @@ class TransportCryptoImpl implements TransportCrypto {
 
 	@Override
 	public TransportKeys deriveTransportKeys(TransportId t,
-			SecretKey master, long rotationPeriod, boolean alice,
+			SecretKey rootKey, long timePeriod, boolean weAreAlice,
 			boolean active) {
-		// Keys for the previous period are derived from the master secret
-		SecretKey inTagPrev = deriveTagKey(master, t, !alice);
-		SecretKey inHeaderPrev = deriveHeaderKey(master, t, !alice);
-		SecretKey outTagPrev = deriveTagKey(master, t, alice);
-		SecretKey outHeaderPrev = deriveHeaderKey(master, t, alice);
+		// Keys for the previous period are derived from the root key
+		SecretKey inTagPrev = deriveTagKey(rootKey, t, !weAreAlice);
+		SecretKey inHeaderPrev = deriveHeaderKey(rootKey, t, !weAreAlice);
+		SecretKey outTagPrev = deriveTagKey(rootKey, t, weAreAlice);
+		SecretKey outHeaderPrev = deriveHeaderKey(rootKey, t, weAreAlice);
 		// Derive the keys for the current and next periods
-		SecretKey inTagCurr = rotateKey(inTagPrev, rotationPeriod);
-		SecretKey inHeaderCurr = rotateKey(inHeaderPrev, rotationPeriod);
-		SecretKey inTagNext = rotateKey(inTagCurr, rotationPeriod + 1);
-		SecretKey inHeaderNext = rotateKey(inHeaderCurr, rotationPeriod + 1);
-		SecretKey outTagCurr = rotateKey(outTagPrev, rotationPeriod);
-		SecretKey outHeaderCurr = rotateKey(outHeaderPrev, rotationPeriod);
+		SecretKey inTagCurr = rotateKey(inTagPrev, timePeriod);
+		SecretKey inHeaderCurr = rotateKey(inHeaderPrev, timePeriod);
+		SecretKey inTagNext = rotateKey(inTagCurr, timePeriod + 1);
+		SecretKey inHeaderNext = rotateKey(inHeaderCurr, timePeriod + 1);
+		SecretKey outTagCurr = rotateKey(outTagPrev, timePeriod);
+		SecretKey outHeaderCurr = rotateKey(outHeaderPrev, timePeriod);
 		// Initialise the reordering windows and stream counters
 		IncomingKeys inPrev = new IncomingKeys(inTagPrev, inHeaderPrev,
-				rotationPeriod - 1);
+				timePeriod - 1);
 		IncomingKeys inCurr = new IncomingKeys(inTagCurr, inHeaderCurr,
-				rotationPeriod);
+				timePeriod);
 		IncomingKeys inNext = new IncomingKeys(inTagNext, inHeaderNext,
-				rotationPeriod + 1);
+				timePeriod + 1);
 		OutgoingKeys outCurr = new OutgoingKeys(outTagCurr, outHeaderCurr,
-				rotationPeriod, active);
+				timePeriod, active);
 		// Collect and return the keys
 		return new TransportKeys(t, inPrev, inCurr, inNext, outCurr);
 	}
 
 	@Override
-	public TransportKeys rotateTransportKeys(TransportKeys k,
-			long rotationPeriod) {
-		if (k.getRotationPeriod() >= rotationPeriod) return k;
+	public TransportKeys rotateTransportKeys(TransportKeys k, long timePeriod) {
+		if (k.getTimePeriod() >= timePeriod) return k;
 		IncomingKeys inPrev = k.getPreviousIncomingKeys();
 		IncomingKeys inCurr = k.getCurrentIncomingKeys();
 		IncomingKeys inNext = k.getNextIncomingKeys();
 		OutgoingKeys outCurr = k.getCurrentOutgoingKeys();
-		long startPeriod = outCurr.getRotationPeriod();
+		long startPeriod = outCurr.getTimePeriod();
 		boolean active = outCurr.isActive();
 		// Rotate the keys
-		for (long p = startPeriod + 1; p <= rotationPeriod; p++) {
+		for (long p = startPeriod + 1; p <= timePeriod; p++) {
 			inPrev = inCurr;
 			inCurr = inNext;
 			SecretKey inNextTag = rotateKey(inNext.getTagKey(), p + 1);
@@ -89,24 +95,117 @@ class TransportCryptoImpl implements TransportCrypto {
 				outCurr);
 	}
 
-	private SecretKey rotateKey(SecretKey k, long rotationPeriod) {
+	private SecretKey rotateKey(SecretKey k, long timePeriod) {
 		byte[] period = new byte[INT_64_BYTES];
-		ByteUtils.writeUint64(rotationPeriod, period, 0);
+		writeUint64(timePeriod, period, 0);
 		return crypto.deriveKey(ROTATE_LABEL, k, period);
 	}
 
-	private SecretKey deriveTagKey(SecretKey master, TransportId t,
-			boolean alice) {
-		String label = alice ? ALICE_TAG_LABEL : BOB_TAG_LABEL;
-		byte[] id = StringUtils.toUtf8(t.getString());
-		return crypto.deriveKey(label, master, id);
+	private SecretKey deriveTagKey(SecretKey rootKey, TransportId t,
+			boolean keyBelongsToAlice) {
+		String label = keyBelongsToAlice ? ALICE_TAG_LABEL : BOB_TAG_LABEL;
+		byte[] id = toUtf8(t.getString());
+		return crypto.deriveKey(label, rootKey, id);
 	}
 
-	private SecretKey deriveHeaderKey(SecretKey master, TransportId t,
-			boolean alice) {
-		String label = alice ? ALICE_HEADER_LABEL : BOB_HEADER_LABEL;
-		byte[] id = StringUtils.toUtf8(t.getString());
-		return crypto.deriveKey(label, master, id);
+	private SecretKey deriveHeaderKey(SecretKey rootKey, TransportId t,
+			boolean keyBelongsToAlice) {
+		String label = keyBelongsToAlice ? ALICE_HEADER_LABEL :
+				BOB_HEADER_LABEL;
+		byte[] id = toUtf8(t.getString());
+		return crypto.deriveKey(label, rootKey, id);
+	}
+
+	@Override
+	public HandshakeKeys deriveHandshakeKeys(TransportId t, SecretKey rootKey,
+			long timePeriod, boolean weAreAlice) {
+		if (timePeriod < 1) throw new IllegalArgumentException();
+		IncomingKeys inPrev = deriveIncomingHandshakeKeys(t, rootKey,
+				weAreAlice, timePeriod - 1);
+		IncomingKeys inCurr = deriveIncomingHandshakeKeys(t, rootKey,
+				weAreAlice, timePeriod);
+		IncomingKeys inNext = deriveIncomingHandshakeKeys(t, rootKey,
+				weAreAlice, timePeriod + 1);
+		OutgoingKeys outCurr = deriveOutgoingHandshakeKeys(t, rootKey,
+				weAreAlice, timePeriod);
+		return new HandshakeKeys(t, inPrev, inCurr, inNext, outCurr, rootKey,
+				weAreAlice);
+	}
+
+	private IncomingKeys deriveIncomingHandshakeKeys(TransportId t,
+			SecretKey rootKey, boolean weAreAlice, long timePeriod) {
+		SecretKey tag = deriveHandshakeTagKey(t, rootKey, !weAreAlice,
+				timePeriod);
+		SecretKey header = deriveHandshakeHeaderKey(t, rootKey, !weAreAlice,
+				timePeriod);
+		return new IncomingKeys(tag, header, timePeriod);
+	}
+
+	private OutgoingKeys deriveOutgoingHandshakeKeys(TransportId t,
+			SecretKey rootKey, boolean weAreAlice, long timePeriod) {
+		SecretKey tag = deriveHandshakeTagKey(t, rootKey, weAreAlice,
+				timePeriod);
+		SecretKey header = deriveHandshakeHeaderKey(t, rootKey, weAreAlice,
+				timePeriod);
+		return new OutgoingKeys(tag, header, timePeriod, true);
+	}
+
+	private SecretKey deriveHandshakeTagKey(TransportId t, SecretKey rootKey,
+			boolean keyBelongsToAlice, long timePeriod) {
+		String label = keyBelongsToAlice ? ALICE_HANDSHAKE_TAG_LABEL :
+				BOB_HANDSHAKE_TAG_LABEL;
+		byte[] id = toUtf8(t.getString());
+		byte[] period = new byte[INT_64_BYTES];
+		writeUint64(timePeriod, period, 0);
+		return crypto.deriveKey(label, rootKey, id, period);
+	}
+
+	private SecretKey deriveHandshakeHeaderKey(TransportId t, SecretKey rootKey,
+			boolean keyBelongsToAlice, long timePeriod) {
+		String label = keyBelongsToAlice ? ALICE_HANDSHAKE_HEADER_LABEL :
+				BOB_HANDSHAKE_HEADER_LABEL;
+		byte[] id = toUtf8(t.getString());
+		byte[] period = new byte[INT_64_BYTES];
+		writeUint64(timePeriod, period, 0);
+		return crypto.deriveKey(label, rootKey, id, period);
+	}
+
+	@Override
+	public HandshakeKeys updateHandshakeKeys(HandshakeKeys k, long timePeriod) {
+		long elapsed = timePeriod - k.getTimePeriod();
+		TransportId t = k.getTransportId();
+		SecretKey rootKey = k.getRootKey();
+		boolean weAreAlice = k.isAlice();
+		if (elapsed <= 0) {
+			// The keys are for the given period or later - don't update them
+			return k;
+		} else if (elapsed == 1) {
+			// The keys are one period old - shift by one period, keeping the
+			// reordering windows for keys we retain
+			IncomingKeys inPrev = k.getCurrentIncomingKeys();
+			IncomingKeys inCurr = k.getNextIncomingKeys();
+			IncomingKeys inNext = deriveIncomingHandshakeKeys(t, rootKey,
+					weAreAlice, timePeriod + 1);
+			OutgoingKeys outCurr = deriveOutgoingHandshakeKeys(t, rootKey,
+					weAreAlice, timePeriod);
+			return new HandshakeKeys(t, inPrev, inCurr, inNext, outCurr,
+					rootKey, weAreAlice);
+		} else if (elapsed == 2) {
+			// The keys are two periods old - shift by two periods, keeping
+			// the reordering windows for keys we retain
+			IncomingKeys inPrev = k.getNextIncomingKeys();
+			IncomingKeys inCurr = deriveIncomingHandshakeKeys(t, rootKey,
+					weAreAlice, timePeriod);
+			IncomingKeys inNext = deriveIncomingHandshakeKeys(t, rootKey,
+					weAreAlice, timePeriod + 1);
+			OutgoingKeys outCurr = deriveOutgoingHandshakeKeys(t, rootKey,
+					weAreAlice, timePeriod);
+			return new HandshakeKeys(t, inPrev, inCurr, inNext, outCurr,
+					rootKey, weAreAlice);
+		} else {
+			// The keys are more than two periods old - derive fresh keys
+			return deriveHandshakeKeys(t, rootKey, timePeriod, weAreAlice);
+		}
 	}
 
 	@Override
@@ -125,14 +224,14 @@ class TransportCryptoImpl implements TransportCrypto {
 		// The input is the protocol version as a 16-bit integer, followed by
 		// the stream number as a 64-bit integer
 		byte[] protocolVersionBytes = new byte[INT_16_BYTES];
-		ByteUtils.writeUint16(protocolVersion, protocolVersionBytes, 0);
+		writeUint16(protocolVersion, protocolVersionBytes, 0);
 		prf.update(protocolVersionBytes, 0, protocolVersionBytes.length);
 		byte[] streamNumberBytes = new byte[INT_64_BYTES];
-		ByteUtils.writeUint64(streamNumber, streamNumberBytes, 0);
+		writeUint64(streamNumber, streamNumberBytes, 0);
 		prf.update(streamNumberBytes, 0, streamNumberBytes.length);
 		byte[] mac = new byte[macLength];
 		prf.doFinal(mac, 0);
 		// The output is the first TAG_LENGTH bytes of the MAC
-		System.arraycopy(mac, 0, tag, 0, TAG_LENGTH);
+		arraycopy(mac, 0, tag, 0, TAG_LENGTH);
 	}
 }

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

@@ -1,29 +0,0 @@
-package org.briarproject.bramble.db;
-
-import org.briarproject.bramble.api.db.DatabaseComponent;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.io.BlockSource;
-import org.briarproject.bramble.api.sync.MessageId;
-
-import javax.inject.Inject;
-
-class BlockSourceImpl implements BlockSource {
-
-	private final DatabaseComponent db;
-
-	@Inject
-	BlockSourceImpl(DatabaseComponent db) {
-		this.db = db;
-	}
-
-	@Override
-	public int getBlockCount(MessageId m) throws DbException {
-		return db.transactionWithResult(true, txn -> db.getBlockCount(txn, m));
-	}
-
-	@Override
-	public byte[] getBlock(MessageId m, int blockNumber) throws DbException {
-		return db.transactionWithResult(true, txn ->
-				db.getBlock(txn, m, blockNumber));
-	}
-}

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

@@ -2,9 +2,13 @@ package org.briarproject.bramble.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.contact.PendingContactState;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.DataTooNewException;
 import org.briarproject.bramble.api.db.DataTooOldException;
+import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.MessageDeletedException;
 import org.briarproject.bramble.api.db.Metadata;
@@ -23,8 +27,11 @@ import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.MessageStatus;
 import org.briarproject.bramble.api.sync.validation.MessageState;
-import org.briarproject.bramble.api.transport.KeySet;
-import org.briarproject.bramble.api.transport.KeySetId;
+import org.briarproject.bramble.api.transport.HandshakeKeySet;
+import org.briarproject.bramble.api.transport.HandshakeKeySetId;
+import org.briarproject.bramble.api.transport.HandshakeKeys;
+import org.briarproject.bramble.api.transport.TransportKeySet;
+import org.briarproject.bramble.api.transport.TransportKeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.util.Collection;
@@ -33,11 +40,14 @@ import java.util.Map;
 import javax.annotation.Nullable;
 
 /**
- * A low-level interface to the database (DatabaseComponent provides a
- * high-level interface). Most operations take a transaction argument, which is
- * obtained by calling {@link #startTransaction()}. Every transaction must be
- * terminated by calling either {@link #abortTransaction(Object) abortTransaction(T)} or
- * {@link #commitTransaction(Object) commitTransaction(T)}, even if an exception is thrown.
+ * A low-level interface to the database ({@link DatabaseComponent} provides a
+ * high-level interface).
+ * <p/>
+ * Most operations take a transaction argument, which is obtained by calling
+ * {@link #startTransaction()}. Every transaction must be terminated by calling
+ * either {@link #abortTransaction(Object) abortTransaction(T)} or
+ * {@link #commitTransaction(Object) commitTransaction(T)}, even if an
+ * exception is thrown.
  */
 @NotNullByDefault
 interface Database<T> {
@@ -77,11 +87,10 @@ interface Database<T> {
 	void commitTransaction(T txn) throws DbException;
 
 	/**
-	 * Stores a contact associated with the given local and remote pseudonyms,
-	 * and returns an ID for the contact.
+	 * Stores a contact with the given pseudonym and returns an ID for the
+	 * contact.
 	 */
-	ContactId addContact(T txn, Author remote, AuthorId local, boolean verified,
-			boolean active) throws DbException;
+	ContactId addContact(T txn, Author a, boolean verified) throws DbException;
 
 	/**
 	 * Stores a group.
@@ -95,6 +104,20 @@ interface Database<T> {
 	void addGroupVisibility(T txn, ContactId c, GroupId g, boolean shared)
 			throws DbException;
 
+	/**
+	 * Stores the given handshake keys for the given contact and returns a
+	 * key set ID.
+	 */
+	HandshakeKeySetId addHandshakeKeys(T txn, ContactId c, HandshakeKeys k)
+			throws DbException;
+
+	/**
+	 * Stores the given handshake keys for the given pending contact and
+	 * returns a key set ID.
+	 */
+	HandshakeKeySetId addHandshakeKeys(T txn, PendingContactId p,
+			HandshakeKeys k) throws DbException;
+
 	/**
 	 * Stores a local pseudonym.
 	 */
@@ -121,6 +144,11 @@ interface Database<T> {
 	 */
 	void addOfferedMessage(T txn, ContactId c, MessageId m) throws DbException;
 
+	/**
+	 * Stores a pending contact.
+	 */
+	void addPendingContact(T txn, PendingContact p) throws DbException;
+
 	/**
 	 * Stores a transport.
 	 */
@@ -131,17 +159,15 @@ interface Database<T> {
 	 * Stores the given transport keys for the given contact and returns a
 	 * key set ID.
 	 */
-	KeySetId addTransportKeys(T txn, ContactId c, TransportKeys k)
+	TransportKeySetId addTransportKeys(T txn, ContactId c, TransportKeys k)
 			throws DbException;
 
 	/**
-	 * Returns true if the database contains the given contact for the given
-	 * local pseudonym.
+	 * Returns true if the database contains the given contact.
 	 * <p/>
 	 * Read-only.
 	 */
-	boolean containsContact(T txn, AuthorId remote, AuthorId local)
-			throws DbException;
+	boolean containsContact(T txn, AuthorId a) throws DbException;
 
 	/**
 	 * Returns true if the database contains the given contact.
@@ -171,6 +197,14 @@ interface Database<T> {
 	 */
 	boolean containsMessage(T txn, MessageId m) throws DbException;
 
+	/**
+	 * Returns true if the database contains the given pending contact.
+	 * <p/>
+	 * Read-only.
+	 */
+	boolean containsPendingContact(T txn, PendingContactId p)
+			throws DbException;
+
 	/**
 	 * Returns true if the database contains the given transport.
 	 * <p/>
@@ -215,6 +249,13 @@ interface Database<T> {
 	 */
 	Contact getContact(T txn, ContactId c) throws DbException;
 
+	/**
+	 * Returns the contact with the given author ID.
+	 * <p/>
+	 * Read-only.
+	 */
+	Contact getContact(T txn, AuthorId a) throws DbException;
+
 	/**
 	 * Returns all contacts.
 	 * <p/>
@@ -222,28 +263,6 @@ interface Database<T> {
 	 */
 	Collection<Contact> getContacts(T txn) throws DbException;
 
-	/**
-	 * Returns a possibly empty collection of contacts with the given author ID.
-	 * <p/>
-	 * Read-only.
-	 */
-	Collection<Contact> getContactsByAuthorId(T txn, AuthorId remote)
-			throws DbException;
-
-	/**
-	 * Returns all contacts associated with the given local pseudonym.
-	 * <p/>
-	 * Read-only.
-	 */
-	Collection<ContactId> getContacts(T txn, AuthorId a) throws DbException;
-
-	/**
-	 * Returns the amount of free storage space available to the database, in
-	 * bytes. This is based on the minimum of the space available on the device
-	 * where the database is stored and the database's configured size.
-	 */
-	long getFreeSpace() throws DbException;
-
 	/**
 	 * Returns the group with the given ID.
 	 * <p/>
@@ -284,6 +303,14 @@ interface Database<T> {
 	Map<ContactId, Boolean> getGroupVisibility(T txn, GroupId g)
 			throws DbException;
 
+	/**
+	 * Returns all handshake keys for the given transport.
+	 * <p/>
+	 * Read-only.
+	 */
+	Collection<HandshakeKeySet> getHandshakeKeys(T txn, TransportId t)
+			throws DbException;
+
 	/**
 	 * Returns the local pseudonym with the given ID.
 	 * <p/>
@@ -474,6 +501,13 @@ interface Database<T> {
 	 */
 	long getNextSendTime(T txn, ContactId c) throws DbException;
 
+	/**
+	 * Returns all pending contacts.
+	 * <p/>
+	 * Read-only.
+	 */
+	Collection<PendingContact> getPendingContacts(T txn) throws DbException;
+
 	/**
 	 * Returns the IDs of some messages that are eligible to be sent to the
 	 * given contact and have been requested by the contact, up to the given
@@ -496,13 +530,19 @@ interface Database<T> {
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<KeySet> getTransportKeys(T txn, TransportId t)
+	Collection<TransportKeySet> getTransportKeys(T txn, TransportId t)
+			throws DbException;
+
+	/**
+	 * Increments the outgoing stream counter for the given handshake keys.
+	 */
+	void incrementStreamCounter(T txn, TransportId t, HandshakeKeySetId k)
 			throws DbException;
 
 	/**
 	 * Increments the outgoing stream counter for the given transport keys.
 	 */
-	void incrementStreamCounter(T txn, TransportId t, KeySetId k)
+	void incrementStreamCounter(T txn, TransportId t, TransportKeySetId k)
 			throws DbException;
 
 	/**
@@ -571,6 +611,12 @@ interface Database<T> {
 	void removeGroupVisibility(T txn, ContactId c, GroupId g)
 			throws DbException;
 
+	/**
+	 * Removes the given handshake keys from the database.
+	 */
+	void removeHandshakeKeys(T txn, TransportId t, HandshakeKeySetId k)
+			throws DbException;
+
 	/**
 	 * Removes a local pseudonym (and all associated state) from the database.
 	 */
@@ -588,6 +634,11 @@ interface Database<T> {
 	void removeOfferedMessages(T txn, ContactId c,
 			Collection<MessageId> requested) throws DbException;
 
+	/**
+	 * Removes a pending contact (and all associated state) from the database.
+	 */
+	void removePendingContact(T txn, PendingContactId p) throws DbException;
+
 	/**
 	 * Removes a transport (and all associated state) from the database.
 	 */
@@ -596,7 +647,7 @@ interface Database<T> {
 	/**
 	 * Removes the given transport keys from the database.
 	 */
-	void removeTransportKeys(T txn, TransportId t, KeySetId k)
+	void removeTransportKeys(T txn, TransportId t, TransportKeySetId k)
 			throws DbException;
 
 	/**
@@ -610,12 +661,6 @@ interface Database<T> {
 	 */
 	void setContactVerified(T txn, ContactId c) throws DbException;
 
-	/**
-	 * Marks the given contact as active or inactive.
-	 */
-	void setContactActive(T txn, ContactId c, boolean active)
-			throws DbException;
-
 	/**
 	 * Sets an alias name for a contact.
 	 */
@@ -641,16 +686,29 @@ interface Database<T> {
 			throws DbException;
 
 	/**
-	 * Sets the reordering window for the given key set and transport in the
-	 * given rotation period.
+	 * Sets the state of the given pending contact.
 	 */
-	void setReorderingWindow(T txn, KeySetId k, TransportId t,
-			long rotationPeriod, long base, byte[] bitmap) throws DbException;
+	void setPendingContactState(T txn, PendingContactId p,
+			PendingContactState state) throws DbException;
+
+	/**
+	 * Sets the reordering window for the given transport key set in the given
+	 * time period.
+	 */
+	void setReorderingWindow(T txn, TransportKeySetId k, TransportId t,
+			long timePeriod, long base, byte[] bitmap) throws DbException;
+
+	/**
+	 * Sets the reordering window for the given handshake key set in the given
+	 * time period.
+	 */
+	void setReorderingWindow(T txn, HandshakeKeySetId k, TransportId t,
+			long timePeriod, long base, byte[] bitmap) throws DbException;
 
 	/**
 	 * Marks the given transport keys as usable for outgoing streams.
 	 */
-	void setTransportKeysActive(T txn, TransportId t, KeySetId k)
+	void setTransportKeysActive(T txn, TransportId t, TransportKeySetId k)
 			throws DbException;
 
 	/**
@@ -661,8 +719,13 @@ interface Database<T> {
 	void updateExpiryTimeAndEta(T txn, ContactId c, MessageId m, int maxLatency)
 			throws DbException;
 
+	/**
+	 * Updates the given handshake keys.
+	 */
+	void updateHandshakeKeys(T txn, HandshakeKeySet ks) throws DbException;
+
 	/**
 	 * Updates the given transport keys following key rotation.
 	 */
-	void updateTransportKeys(T txn, KeySet ks) throws DbException;
+	void updateTransportKeys(T txn, TransportKeySet ks) throws DbException;
 }

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

@@ -2,28 +2,34 @@ package org.briarproject.bramble.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.contact.event.ContactAddedEvent;
 import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
-import org.briarproject.bramble.api.contact.event.ContactStatusChangedEvent;
 import org.briarproject.bramble.api.contact.event.ContactVerifiedEvent;
 import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.db.CommitAction;
+import org.briarproject.bramble.api.db.CommitAction.Visitor;
 import org.briarproject.bramble.api.db.ContactExistsException;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbCallable;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.DbRunnable;
+import org.briarproject.bramble.api.db.EventAction;
 import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.MigrationListener;
-import org.briarproject.bramble.api.db.NoSuchBlockException;
 import org.briarproject.bramble.api.db.NoSuchContactException;
 import org.briarproject.bramble.api.db.NoSuchGroupException;
 import org.briarproject.bramble.api.db.NoSuchLocalAuthorException;
 import org.briarproject.bramble.api.db.NoSuchMessageException;
+import org.briarproject.bramble.api.db.NoSuchPendingContactException;
 import org.briarproject.bramble.api.db.NoSuchTransportException;
 import org.briarproject.bramble.api.db.NullableDbCallable;
+import org.briarproject.bramble.api.db.PendingContactExistsException;
+import org.briarproject.bramble.api.db.TaskAction;
 import org.briarproject.bramble.api.db.Transaction;
-import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventExecutor;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.identity.LocalAuthor;
@@ -56,8 +62,11 @@ import org.briarproject.bramble.api.sync.event.MessageToRequestEvent;
 import org.briarproject.bramble.api.sync.event.MessagesAckedEvent;
 import org.briarproject.bramble.api.sync.event.MessagesSentEvent;
 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.HandshakeKeySet;
+import org.briarproject.bramble.api.transport.HandshakeKeySetId;
+import org.briarproject.bramble.api.transport.HandshakeKeys;
+import org.briarproject.bramble.api.transport.TransportKeySet;
+import org.briarproject.bramble.api.transport.TransportKeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.util.ArrayList;
@@ -65,6 +74,7 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 import java.util.logging.Logger;
@@ -93,25 +103,29 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	private final Database<T> db;
 	private final Class<T> txnClass;
 	private final EventBus eventBus;
-	private final ShutdownManager shutdown;
+	private final Executor eventExecutor;
+	private final ShutdownManager shutdownManager;
 	private final AtomicBoolean closed = new AtomicBoolean(false);
 	private final ReentrantReadWriteLock lock =
 			new ReentrantReadWriteLock(true);
+	private final Visitor visitor = new CommitActionVisitor();
 
 	@Inject
 	DatabaseComponentImpl(Database<T> db, Class<T> txnClass, EventBus eventBus,
-			ShutdownManager shutdown) {
+			@EventExecutor Executor eventExecutor,
+			ShutdownManager shutdownManager) {
 		this.db = db;
 		this.txnClass = txnClass;
 		this.eventBus = eventBus;
-		this.shutdown = shutdown;
+		this.eventExecutor = eventExecutor;
+		this.shutdownManager = shutdownManager;
 	}
 
 	@Override
 	public boolean open(SecretKey key, @Nullable MigrationListener listener)
 			throws DbException {
 		boolean reopened = db.open(key, listener);
-		shutdown.addShutdownHook(() -> {
+		shutdownManager.addShutdownHook(() -> {
 			try {
 				close();
 			} catch (DbException e) {
@@ -161,13 +175,16 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	public void endTransaction(Transaction transaction) {
 		try {
 			T txn = txnClass.cast(transaction.unbox());
-			if (!transaction.isCommitted()) db.abortTransaction(txn);
+			if (transaction.isCommitted()) {
+				for (CommitAction a : transaction.getActions())
+					a.accept(visitor);
+			} else {
+				db.abortTransaction(txn);
+			}
 		} finally {
 			if (transaction.isReadOnly()) lock.readLock().unlock();
 			else lock.writeLock().unlock();
 		}
-		if (transaction.isCommitted())
-			for (Event e : transaction.getEvents()) eventBus.broadcast(e);
 	}
 
 	@Override
@@ -215,20 +232,16 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public ContactId addContact(Transaction transaction, Author remote,
-			AuthorId local, boolean verified, boolean active)
-			throws DbException {
+	public ContactId addContact(Transaction transaction, Author a,
+			boolean verified) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
-		if (!db.containsLocalAuthor(txn, local))
-			throw new NoSuchLocalAuthorException();
-		if (db.containsLocalAuthor(txn, remote.getId()))
+		if (db.containsLocalAuthor(txn, a.getId()))
 			throw new ContactExistsException();
-		if (db.containsContact(txn, remote.getId(), local))
+		if (db.containsContact(txn, a.getId()))
 			throw new ContactExistsException();
-		ContactId c = db.addContact(txn, remote, local, verified, active);
-		transaction.attach(new ContactAddedEvent(c, active));
-		if (active) transaction.attach(new ContactStatusChangedEvent(c, true));
+		ContactId c = db.addContact(txn, a, verified);
+		transaction.attach(new ContactAddedEvent(c));
 		return c;
 	}
 
@@ -242,6 +255,30 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		}
 	}
 
+	@Override
+	public HandshakeKeySetId addHandshakeKeys(Transaction transaction,
+			ContactId c, HandshakeKeys k) throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsContact(txn, c))
+			throw new NoSuchContactException();
+		if (!db.containsTransport(txn, k.getTransportId()))
+			throw new NoSuchTransportException();
+		return db.addHandshakeKeys(txn, c, k);
+	}
+
+	@Override
+	public HandshakeKeySetId addHandshakeKeys(Transaction transaction,
+			PendingContactId p, HandshakeKeys k) throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsPendingContact(txn, p))
+			throw new NoSuchPendingContactException();
+		if (!db.containsTransport(txn, k.getTransportId()))
+			throw new NoSuchTransportException();
+		return db.addHandshakeKeys(txn, p, k);
+	}
+
 	@Override
 	public void addLocalAuthor(Transaction transaction, LocalAuthor a)
 			throws DbException {
@@ -270,6 +307,16 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		db.mergeMessageMetadata(txn, m.getId(), meta);
 	}
 
+	@Override
+	public void addPendingContact(Transaction transaction, PendingContact p)
+			throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (db.containsPendingContact(txn, p.getId()))
+			throw new PendingContactExistsException();
+		db.addPendingContact(txn, p);
+	}
+
 	@Override
 	public void addTransport(Transaction transaction, TransportId t,
 			int maxLatency) throws DbException {
@@ -280,8 +327,8 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public KeySetId addTransportKeys(Transaction transaction, ContactId c,
-			TransportKeys k) throws DbException {
+	public TransportKeySetId addTransportKeys(Transaction transaction,
+			ContactId c, TransportKeys k) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
 		if (!db.containsContact(txn, c))
@@ -292,12 +339,10 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public boolean containsContact(Transaction transaction, AuthorId remote,
-			AuthorId local) throws DbException {
+	public boolean containsContact(Transaction transaction, AuthorId a)
+			throws DbException {
 		T txn = unbox(transaction);
-		if (!db.containsLocalAuthor(txn, local))
-			throw new NoSuchLocalAuthorException();
-		return db.containsContact(txn, remote, local);
+		return db.containsContact(txn, a);
 	}
 
 	@Override
@@ -314,6 +359,13 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.containsLocalAuthor(txn, local);
 	}
 
+	@Override
+	public boolean containsPendingContact(Transaction transaction,
+			PendingContactId p) throws DbException {
+		T txn = unbox(transaction);
+		return db.containsPendingContact(txn, p);
+	}
+
 	@Override
 	public void deleteMessage(Transaction transaction, MessageId m)
 			throws DbException {
@@ -421,26 +473,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return messages;
 	}
 
-	@Override
-	public int getBlockCount(Transaction transaction, MessageId m)
-			throws DbException {
-		T txn = unbox(transaction);
-		if (!db.containsMessage(txn, m))
-			throw new NoSuchMessageException();
-		return 1;
-	}
-
-	@Override
-	public byte[] getBlock(Transaction transaction, MessageId m,
-			int blockNumber) throws DbException {
-		T txn = unbox(transaction);
-		if (!db.containsMessage(txn, m))
-			throw new NoSuchMessageException();
-		if (blockNumber != 0)
-			throw new NoSuchBlockException();
-		return db.getMessage(txn, m).getBody();
-	}
-
 	@Override
 	public Contact getContact(Transaction transaction, ContactId c)
 			throws DbException {
@@ -450,6 +482,15 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.getContact(txn, c);
 	}
 
+	@Override
+	public Contact getContact(Transaction transaction, AuthorId a)
+			throws DbException {
+		T txn = unbox(transaction);
+		if (!db.containsContact(txn, a))
+			throw new NoSuchContactException();
+		return db.getContact(txn, a);
+	}
+
 	@Override
 	public Collection<Contact> getContacts(Transaction transaction)
 			throws DbException {
@@ -457,22 +498,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.getContacts(txn);
 	}
 
-	@Override
-	public Collection<Contact> getContactsByAuthorId(Transaction transaction,
-			AuthorId remote) throws DbException {
-		T txn = unbox(transaction);
-		return db.getContactsByAuthorId(txn, remote);
-	}
-
-	@Override
-	public Collection<ContactId> getContacts(Transaction transaction,
-			AuthorId a) throws DbException {
-		T txn = unbox(transaction);
-		if (!db.containsLocalAuthor(txn, a))
-			throw new NoSuchLocalAuthorException();
-		return db.getContacts(txn, a);
-	}
-
 	@Override
 	public Group getGroup(Transaction transaction, GroupId g)
 			throws DbException {
@@ -507,6 +532,15 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.getGroupVisibility(txn, c, g);
 	}
 
+	@Override
+	public Collection<HandshakeKeySet> getHandshakeKeys(Transaction transaction,
+			TransportId t) throws DbException {
+		T txn = unbox(transaction);
+		if (!db.containsTransport(txn, t))
+			throw new NoSuchTransportException();
+		return db.getHandshakeKeys(txn, t);
+	}
+
 	@Override
 	public LocalAuthor getLocalAuthor(Transaction transaction, AuthorId a)
 			throws DbException {
@@ -664,6 +698,13 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.getNextSendTime(txn, c);
 	}
 
+	@Override
+	public Collection<PendingContact> getPendingContacts(
+			Transaction transaction) throws DbException {
+		T txn = unbox(transaction);
+		return db.getPendingContacts(txn);
+	}
+
 	@Override
 	public Settings getSettings(Transaction transaction, String namespace)
 			throws DbException {
@@ -672,7 +713,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public Collection<KeySet> getTransportKeys(Transaction transaction,
+	public Collection<TransportKeySet> getTransportKeys(Transaction transaction,
 			TransportId t) throws DbException {
 		T txn = unbox(transaction);
 		if (!db.containsTransport(txn, t))
@@ -682,7 +723,17 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 
 	@Override
 	public void incrementStreamCounter(Transaction transaction, TransportId t,
-			KeySetId k) throws DbException {
+			HandshakeKeySetId k) throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsTransport(txn, t))
+			throw new NoSuchTransportException();
+		db.incrementStreamCounter(txn, t, k);
+	}
+
+	@Override
+	public void incrementStreamCounter(Transaction transaction, TransportId t,
+			TransportKeySetId k) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
 		if (!db.containsTransport(txn, t))
@@ -831,6 +882,16 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		transaction.attach(new GroupVisibilityUpdatedEvent(affected));
 	}
 
+	@Override
+	public void removeHandshakeKeys(Transaction transaction,
+			TransportId t, HandshakeKeySetId k) throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsTransport(txn, t))
+			throw new NoSuchTransportException();
+		db.removeHandshakeKeys(txn, t, k);
+	}
+
 	@Override
 	public void removeLocalAuthor(Transaction transaction, AuthorId a)
 			throws DbException {
@@ -853,6 +914,16 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		db.removeMessage(txn, m);
 	}
 
+	@Override
+	public void removePendingContact(Transaction transaction,
+			PendingContactId p) throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsPendingContact(txn, p))
+			throw new NoSuchPendingContactException();
+		db.removePendingContact(txn, p);
+	}
+
 	@Override
 	public void removeTransport(Transaction transaction, TransportId t)
 			throws DbException {
@@ -865,7 +936,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 
 	@Override
 	public void removeTransportKeys(Transaction transaction,
-			TransportId t, KeySetId k) throws DbException {
+			TransportId t, TransportKeySetId k) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
 		if (!db.containsTransport(txn, t))
@@ -884,17 +955,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		transaction.attach(new ContactVerifiedEvent(c));
 	}
 
-	@Override
-	public void setContactActive(Transaction transaction, ContactId c,
-			boolean active) throws DbException {
-		if (transaction.isReadOnly()) throw new IllegalArgumentException();
-		T txn = unbox(transaction);
-		if (!db.containsContact(txn, c))
-			throw new NoSuchContactException();
-		db.setContactActive(txn, c, active);
-		transaction.attach(new ContactStatusChangedEvent(c, active));
-	}
-
 	@Override
 	public void setContactAlias(Transaction transaction, ContactId c,
 			@Nullable String alias) throws DbException {
@@ -964,19 +1024,30 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public void setReorderingWindow(Transaction transaction, KeySetId k,
-			TransportId t, long rotationPeriod, long base, byte[] bitmap)
-			throws DbException {
+	public void setReorderingWindow(Transaction transaction,
+			TransportKeySetId k, TransportId t, long timePeriod, long base,
+			byte[] bitmap) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
 		if (!db.containsTransport(txn, t))
 			throw new NoSuchTransportException();
-		db.setReorderingWindow(txn, k, t, rotationPeriod, base, bitmap);
+		db.setReorderingWindow(txn, k, t, timePeriod, base, bitmap);
+	}
+
+	@Override
+	public void setReorderingWindow(Transaction transaction,
+			HandshakeKeySetId k, TransportId t, long timePeriod, long base,
+			byte[] bitmap) throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsTransport(txn, t))
+			throw new NoSuchTransportException();
+		db.setReorderingWindow(txn, k, t, timePeriod, base, bitmap);
 	}
 
 	@Override
 	public void setTransportKeysActive(Transaction transaction, TransportId t,
-			KeySetId k) throws DbException {
+			TransportKeySetId k) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
 		if (!db.containsTransport(txn, t))
@@ -985,14 +1056,39 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public void updateTransportKeys(Transaction transaction,
-			Collection<KeySet> keys) throws DbException {
+	public void updateHandshakeKeys(Transaction transaction,
+			Collection<HandshakeKeySet> keys) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
-		for (KeySet ks : keys) {
-			TransportId t = ks.getTransportKeys().getTransportId();
+		for (HandshakeKeySet ks : keys) {
+			TransportId t = ks.getKeys().getTransportId();
+			if (db.containsTransport(txn, t))
+				db.updateHandshakeKeys(txn, ks);
+		}
+	}
+
+	@Override
+	public void updateTransportKeys(Transaction transaction,
+			Collection<TransportKeySet> keys) throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		for (TransportKeySet ks : keys) {
+			TransportId t = ks.getKeys().getTransportId();
 			if (db.containsTransport(txn, t))
 				db.updateTransportKeys(txn, ks);
 		}
 	}
+
+	private class CommitActionVisitor implements Visitor {
+
+		@Override
+		public void visit(EventAction a) {
+			eventBus.broadcast(a.getEvent());
+		}
+
+		@Override
+		public void visit(TaskAction a) {
+			eventExecutor.execute(a.getTask());
+		}
+	}
 }

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

@@ -3,12 +3,13 @@ package org.briarproject.bramble.db;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseConfig;
 import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.io.BlockSource;
+import org.briarproject.bramble.api.event.EventExecutor;
 import org.briarproject.bramble.api.lifecycle.ShutdownManager;
 import org.briarproject.bramble.api.sync.MessageFactory;
 import org.briarproject.bramble.api.system.Clock;
 
 import java.sql.Connection;
+import java.util.concurrent.Executor;
 
 import javax.inject.Singleton;
 
@@ -28,13 +29,9 @@ public class DatabaseModule {
 	@Provides
 	@Singleton
 	DatabaseComponent provideDatabaseComponent(Database<Connection> db,
-			EventBus eventBus, ShutdownManager shutdown) {
+			EventBus eventBus, @EventExecutor Executor eventExecutor,
+			ShutdownManager shutdownManager) {
 		return new DatabaseComponentImpl<>(db, Connection.class, eventBus,
-				shutdown);
-	}
-
-	@Provides
-	BlockSource provideBlockSource(BlockSourceImpl blockSource) {
-		return blockSource;
+				eventExecutor, shutdownManager);
 	}
 }

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

@@ -76,30 +76,6 @@ class H2Database extends JdbcDatabase {
 		}
 	}
 
-	@Override
-	public long getFreeSpace() {
-		File dir = config.getDatabaseDirectory();
-		long maxSize = config.getMaxSize();
-		long free = dir.getFreeSpace();
-		long used = getDiskSpace(dir);
-		long quota = maxSize - used;
-		return Math.min(free, quota);
-	}
-
-	private long getDiskSpace(File f) {
-		if (f.isDirectory()) {
-			long total = 0;
-			File[] children = f.listFiles();
-			if (children != null)
-				for (File child : children) total += getDiskSpace(child);
-			return total;
-		} else if (f.isFile()) {
-			return f.length();
-		} else {
-			return 0;
-		}
-	}
-
 	@Override
 	protected Connection createConnection() throws SQLException {
 		SecretKey key = this.key;

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

@@ -86,30 +86,6 @@ class HyperSqlDatabase extends JdbcDatabase {
 		}
 	}
 
-	@Override
-	public long getFreeSpace() {
-		File dir = config.getDatabaseDirectory();
-		long maxSize = config.getMaxSize();
-		long free = dir.getFreeSpace();
-		long used = getDiskSpace(dir);
-		long quota = maxSize - used;
-		return Math.min(free, quota);
-	}
-
-	private long getDiskSpace(File f) {
-		if (f.isDirectory()) {
-			long total = 0;
-			File[] children = f.listFiles();
-			if (children != null)
-				for (File child : children) total += getDiskSpace(child);
-			return total;
-		} else if (f.isFile()) {
-			return f.length();
-		} else {
-			return 0;
-		}
-	}
-
 	@Override
 	protected Connection createConnection() throws SQLException {
 		SecretKey key = this.key;

bramble-core/src/main/java/org/briarproject/bramble/db/Migration40_41.java

@@ -17,7 +17,7 @@ class Migration40_41 implements Migration<Connection> {
 
 	private final DatabaseTypes dbTypes;
 
-	public Migration40_41(DatabaseTypes databaseTypes) {
+	Migration40_41(DatabaseTypes databaseTypes) {
 		this.dbTypes = databaseTypes;
 	}
 

bramble-core/src/main/java/org/briarproject/bramble/db/Migration41_42.java

@@ -0,0 +1,97 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.db.DbException;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.logging.Logger;
+
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.db.JdbcUtils.tryToClose;
+
+class Migration41_42 implements Migration<Connection> {
+
+	private static final Logger LOG = getLogger(Migration41_42.class.getName());
+
+	private final DatabaseTypes dbTypes;
+
+	Migration41_42(DatabaseTypes dbTypes) {
+		this.dbTypes = dbTypes;
+	}
+
+	@Override
+	public int getStartVersion() {
+		return 41;
+	}
+
+	@Override
+	public int getEndVersion() {
+		return 42;
+	}
+
+	@Override
+	public void migrate(Connection txn) throws DbException {
+		Statement s = null;
+		try {
+			s = txn.createStatement();
+			s.execute("ALTER TABLE outgoingKeys"
+					+ " ALTER COLUMN rotationPeriod"
+					+ " RENAME TO timePeriod");
+			s.execute("ALTER TABLE incomingKeys"
+					+ " ALTER COLUMN rotationPeriod"
+					+ " RENAME TO timePeriod");
+			s.execute("ALTER TABLE incomingKeys"
+					+ " DROP COLUMN contactId");
+			s.execute(dbTypes.replaceTypes("CREATE TABLE pendingContacts"
+					+ " (pendingContactId _HASH NOT NULL,"
+					+ " publicKey _BINARY NOT NULL,"
+					+ " alias _STRING NOT NULL,"
+					+ " state INT NOT NULL,"
+					+ " timestamp BIGINT NOT NULL,"
+					+ " PRIMARY KEY (pendingContactId))"));
+			s.execute(dbTypes.replaceTypes("CREATE TABLE outgoingHandshakeKeys"
+					+ " (transportId _STRING NOT NULL,"
+					+ " keySetId _COUNTER,"
+					+ " timePeriod BIGINT NOT NULL,"
+					+ " contactId INT," // Null if contact is pending
+					+ " pendingContactId _HASH," // Null if not pending
+					+ " rootKey _SECRET NOT NULL,"
+					+ " alice BOOLEAN NOT NULL,"
+					+ " tagKey _SECRET NOT NULL,"
+					+ " headerKey _SECRET NOT NULL,"
+					+ " stream BIGINT NOT NULL,"
+					+ " PRIMARY KEY (transportId, keySetId),"
+					+ " FOREIGN KEY (transportId)"
+					+ " REFERENCES transports (transportId)"
+					+ " ON DELETE CASCADE,"
+					+ " UNIQUE (keySetId),"
+					+ " FOREIGN KEY (contactId)"
+					+ " REFERENCES contacts (contactId)"
+					+ " ON DELETE CASCADE,"
+					+ " FOREIGN KEY (pendingContactId)"
+					+ " REFERENCES pendingContacts (pendingContactId)"
+					+ " ON DELETE CASCADE)"));
+			s.execute(dbTypes.replaceTypes("CREATE TABLE incomingHandshakeKeys"
+					+ " (transportId _STRING NOT NULL,"
+					+ " keySetId INT NOT NULL,"
+					+ " timePeriod BIGINT NOT NULL,"
+					+ " tagKey _SECRET NOT NULL,"
+					+ " headerKey _SECRET NOT NULL,"
+					+ " base BIGINT NOT NULL,"
+					+ " bitmap _BINARY NOT NULL,"
+					+ " periodOffset INT NOT NULL,"
+					+ " PRIMARY KEY (transportId, keySetId, periodOffset),"
+					+ " FOREIGN KEY (transportId)"
+					+ " REFERENCES transports (transportId)"
+					+ " ON DELETE CASCADE,"
+					+ " FOREIGN KEY (keySetId)"
+					+ " REFERENCES outgoingHandshakeKeys (keySetId)"
+					+ " ON DELETE CASCADE)"));
+		} catch (SQLException e) {
+			tryToClose(s, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/db/Migration42_43.java

@@ -0,0 +1,52 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.db.DbException;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.logging.Logger;
+
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.db.JdbcUtils.tryToClose;
+
+class Migration42_43 implements Migration<Connection> {
+
+	private static final Logger LOG = getLogger(Migration42_43.class.getName());
+
+	private final DatabaseTypes dbTypes;
+
+	Migration42_43(DatabaseTypes dbTypes) {
+		this.dbTypes = dbTypes;
+	}
+
+	@Override
+	public int getStartVersion() {
+		return 42;
+	}
+
+	@Override
+	public int getEndVersion() {
+		return 43;
+	}
+
+	@Override
+	public void migrate(Connection txn) throws DbException {
+		Statement s = null;
+		try {
+			s = txn.createStatement();
+			s.execute(dbTypes.replaceTypes("ALTER TABLE localAuthors"
+					+ " ADD COLUMN handshakePublicKey _BINARY"));
+			s.execute(dbTypes.replaceTypes("ALTER TABLE localAuthors"
+					+ " ADD COLUMN handshakePrivateKey _BINARY"));
+			s.execute(dbTypes.replaceTypes("ALTER TABLE contacts"
+					+ " ADD COLUMN handshakePublicKey _BINARY"));
+			s.execute("ALTER TABLE contacts"
+					+ " DROP COLUMN active");
+		} catch (SQLException e) {
+			tryToClose(s, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/db/Migration43_44.java

@@ -0,0 +1,40 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.db.DbException;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.logging.Logger;
+
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.db.JdbcUtils.tryToClose;
+
+class Migration43_44 implements Migration<Connection> {
+
+	private static final Logger LOG = getLogger(Migration43_44.class.getName());
+
+	@Override
+	public int getStartVersion() {
+		return 43;
+	}
+
+	@Override
+	public int getEndVersion() {
+		return 44;
+	}
+
+	@Override
+	public void migrate(Connection txn) throws DbException {
+		Statement s = null;
+		try {
+			s = txn.createStatement();
+			s.execute("ALTER TABLE contacts"
+					+ " DROP COLUMN localAuthorId");
+		} catch (SQLException e) {
+			tryToClose(s, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+}

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

@@ -0,0 +1,32 @@
+package org.briarproject.bramble.event;
+
+import org.briarproject.bramble.api.event.EventExecutor;
+
+import java.util.concurrent.Executor;
+
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+import static java.util.concurrent.Executors.newSingleThreadExecutor;
+
+/**
+ * Default implementation of {@link EventExecutor} that uses a dedicated thread
+ * to notify listeners of events. Applications may prefer to supply an
+ * implementation that uses an existing thread, such as the UI thread.
+ */
+@Module
+public class DefaultEventExecutorModule {
+
+	@Provides
+	@Singleton
+	@EventExecutor
+	Executor provideEventExecutor() {
+		return newSingleThreadExecutor(r -> {
+			Thread t = new Thread(r);
+			t.setDaemon(true);
+			return t;
+		});
+	}
+}

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

@@ -2,13 +2,16 @@ package org.briarproject.bramble.event;
 
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventExecutor;
 import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.util.Collection;
 import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.Executor;
 
 import javax.annotation.concurrent.ThreadSafe;
+import javax.inject.Inject;
 
 @ThreadSafe
 @NotNullByDefault
@@ -16,6 +19,12 @@ class EventBusImpl implements EventBus {
 
 	private final Collection<EventListener> listeners =
 			new CopyOnWriteArrayList<>();
+	private final Executor eventExecutor;
+
+	@Inject
+	EventBusImpl(@EventExecutor Executor eventExecutor) {
+		this.eventExecutor = eventExecutor;
+	}
 
 	@Override
 	public void addListener(EventListener l) {
@@ -29,6 +38,8 @@ class EventBusImpl implements EventBus {
 
 	@Override
 	public void broadcast(Event e) {
-		for (EventListener l : listeners) l.eventOccurred(e);
+		eventExecutor.execute(() -> {
+			for (EventListener l : listeners) l.eventOccurred(e);
+		});
 	}
 }

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

@@ -12,7 +12,7 @@ public class EventModule {
 
 	@Provides
 	@Singleton
-	EventBus provideEventBus() {
-		return new EventBusImpl();
+	EventBus provideEventBus(EventBusImpl eventBus) {
+		return eventBus;
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/io/BlockInputStream.java

@@ -1,155 +0,0 @@
-package org.briarproject.bramble.io;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.InterruptedIOException;
-import java.util.concurrent.ArrayBlockingQueue;
-import java.util.concurrent.BlockingQueue;
-
-import javax.annotation.Nullable;
-import javax.annotation.concurrent.GuardedBy;
-import javax.annotation.concurrent.ThreadSafe;
-
-import static java.lang.System.arraycopy;
-import static java.lang.Thread.currentThread;
-
-/**
- * An {@link InputStream} that asynchronously fetches blocks of data on demand.
- */
-@ThreadSafe
-@NotNullByDefault
-abstract class BlockInputStream extends InputStream {
-
-	private final int minBufferBytes;
-	private final BlockingQueue<Buffer> queue = new ArrayBlockingQueue<>(1);
-	private final Object lock = new Object();
-
-	@GuardedBy("lock")
-	@Nullable
-	private Buffer buffer = null;
-
-	@GuardedBy("lock")
-	private int offset = 0;
-
-	@GuardedBy("lock")
-	private boolean fetchingBlock = false;
-
-	abstract void fetchBlockAsync(int blockNumber);
-
-	BlockInputStream(int minBufferBytes) {
-		this.minBufferBytes = minBufferBytes;
-	}
-
-	@Override
-	public int read() throws IOException {
-		synchronized (lock) {
-			if (!prepareRead()) return -1;
-			if (buffer == null) throw new AssertionError();
-			return buffer.data[offset++] & 0xFF;
-		}
-	}
-
-	@Override
-	public int read(byte[] b) throws IOException {
-		return read(b, 0, b.length);
-	}
-
-	@Override
-	public int read(byte[] b, int off, int len) throws IOException {
-		if (off < 0 || len < 0 || off + len > b.length)
-			throw new IllegalArgumentException();
-		synchronized (lock) {
-			if (!prepareRead()) return -1;
-			if (buffer == null) throw new AssertionError();
-			len = Math.min(len, buffer.length - offset);
-			if (len < 0) throw new AssertionError();
-			arraycopy(buffer.data, offset, b, off, len);
-			offset += len;
-			return len;
-		}
-	}
-
-	private boolean prepareRead() throws IOException {
-		throwExceptionIfNecessary();
-		if (isEndOfStream()) return false;
-		if (shouldFetchBlock()) fetchBlockAsync();
-		waitForBlock();
-		if (buffer == null) throw new AssertionError();
-		return offset < buffer.length;
-	}
-
-	@GuardedBy("lock")
-	private void throwExceptionIfNecessary() throws IOException {
-		if (buffer != null && buffer.exception != null)
-			throw new IOException(buffer.exception);
-	}
-
-	@GuardedBy("lock")
-	private boolean isEndOfStream() {
-		return buffer != null && offset == buffer.length && !fetchingBlock;
-	}
-
-	@GuardedBy("lock")
-	private boolean shouldFetchBlock() {
-		if (fetchingBlock) return false;
-		if (buffer == null) return true;
-		if (buffer.length == 0) return false;
-		return buffer.length - offset < minBufferBytes;
-	}
-
-	@GuardedBy("lock")
-	private void fetchBlockAsync() {
-		if (buffer == null) fetchBlockAsync(0);
-		else fetchBlockAsync(buffer.blockNumber + 1);
-		fetchingBlock = true;
-	}
-
-	@GuardedBy("lock")
-	private void waitForBlock() throws IOException {
-		if (buffer != null && offset < buffer.length) return;
-		try {
-			buffer = queue.take();
-		} catch (InterruptedException e) {
-			currentThread().interrupt();
-			throw new InterruptedIOException();
-		}
-		fetchingBlock = false;
-		offset = 0;
-		throwExceptionIfNecessary();
-	}
-
-	void fetchSucceeded(int blockNumber, byte[] data, int length) {
-		queue.add(new Buffer(blockNumber, data, length));
-	}
-
-	void fetchFailed(int blockNumber, Exception exception) {
-		queue.add(new Buffer(blockNumber, exception));
-	}
-
-	private static class Buffer {
-
-		private final int blockNumber;
-		private final byte[] data;
-		private final int length;
-		@Nullable
-		private final Exception exception;
-
-		private Buffer(int blockNumber, byte[] data, int length) {
-			if (length < 0 || length > data.length)
-				throw new IllegalArgumentException();
-			this.blockNumber = blockNumber;
-			this.data = data;
-			this.length = length;
-			exception = null;
-		}
-
-		private Buffer(int blockNumber, Exception exception) {
-			this.blockNumber = blockNumber;
-			this.exception = exception;
-			data = new byte[0];
-			length = 0;
-		}
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/io/BlockSourceInputStream.java

@@ -1,53 +0,0 @@
-package org.briarproject.bramble.io;
-
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.io.BlockSource;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.sync.MessageId;
-
-import java.util.concurrent.Executor;
-
-import javax.annotation.concurrent.ThreadSafe;
-
-/**
- * A {@link BlockInputStream} that fetches data from a {@link BlockSource}.
- */
-@ThreadSafe
-@NotNullByDefault
-class BlockSourceInputStream extends BlockInputStream {
-
-	private final Executor executor;
-	private final BlockSource blockSource;
-	private final MessageId messageId;
-
-	private volatile int blockCount = -1;
-
-	BlockSourceInputStream(int minBufferBytes, Executor executor,
-			BlockSource blockSource, MessageId messageId) {
-		super(minBufferBytes);
-		this.executor = executor;
-		this.blockSource = blockSource;
-		this.messageId = messageId;
-	}
-
-	@Override
-	void fetchBlockAsync(int blockNumber) {
-		executor.execute(() -> {
-			try {
-				if (blockCount == -1) {
-					blockCount = blockSource.getBlockCount(messageId);
-				}
-				if (blockNumber > blockCount) {
-					fetchFailed(blockNumber, new IllegalArgumentException());
-				} else if (blockNumber == blockCount) {
-					fetchSucceeded(blockNumber, new byte[0], 0); // EOF
-				} else {
-					byte[] block = blockSource.getBlock(messageId, blockNumber);
-					fetchSucceeded(blockNumber, block, block.length);
-				}
-			} catch (DbException e) {
-				fetchFailed(blockNumber, e);
-			}
-		});
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/io/IoModule.java

@@ -1,16 +0,0 @@
-package org.briarproject.bramble.io;
-
-import org.briarproject.bramble.api.io.MessageInputStreamFactory;
-
-import dagger.Module;
-import dagger.Provides;
-
-@Module
-public class IoModule {
-
-	@Provides
-	MessageInputStreamFactory provideMessageInputStreamFactory(
-			MessageInputStreamFactoryImpl messageInputStreamFactory) {
-		return messageInputStreamFactory;
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/io/MessageInputStreamFactoryImpl.java

@@ -1,32 +0,0 @@
-package org.briarproject.bramble.io;
-
-import org.briarproject.bramble.api.db.DatabaseExecutor;
-import org.briarproject.bramble.api.io.BlockSource;
-import org.briarproject.bramble.api.io.MessageInputStreamFactory;
-import org.briarproject.bramble.api.sync.MessageId;
-
-import java.io.InputStream;
-import java.util.concurrent.Executor;
-
-import javax.inject.Inject;
-
-import static org.briarproject.bramble.api.sync.SyncConstants.MAX_BLOCK_LENGTH;
-
-class MessageInputStreamFactoryImpl implements MessageInputStreamFactory {
-
-	private final Executor dbExecutor;
-	private final BlockSource blockSource;
-
-	@Inject
-	MessageInputStreamFactoryImpl(@DatabaseExecutor Executor dbExecutor,
-			BlockSource blockSource) {
-		this.dbExecutor = dbExecutor;
-		this.blockSource = blockSource;
-	}
-
-	@Override
-	public InputStream getMessageInputStream(MessageId m) {
-		return new BlockSourceInputStream(MAX_BLOCK_LENGTH, dbExecutor,
-				blockSource, m);
-	}
-}

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

@@ -14,7 +14,7 @@ import java.io.IOException;
 import java.security.GeneralSecurityException;
 import java.util.Arrays;
 
-import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.MASTER_SECRET_LABEL;
+import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.MASTER_KEY_LABEL;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.PROTOCOL_VERSION;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.SHARED_SECRET_LABEL;
 
@@ -90,7 +90,7 @@ class KeyAgreementProtocol {
 	/**
 	 * Perform the BQP protocol.
 	 *
-	 * @return the negotiated master secret.
+	 * @return the negotiated master key.
 	 * @throws AbortException when the protocol may have been tampered with.
 	 * @throws IOException for all other other connection errors.
 	 */
@@ -115,7 +115,7 @@ class KeyAgreementProtocol {
 				receiveConfirm(s, theirPublicKey);
 				sendConfirm(s, theirPublicKey);
 			}
-			return crypto.deriveKey(MASTER_SECRET_LABEL, s);
+			return crypto.deriveKey(MASTER_KEY_LABEL, s);
 		} catch (AbortException e) {
 			sendAbort(e.getCause() != null);
 			throw e;

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

@@ -114,9 +114,9 @@ class KeyAgreementTaskImpl extends Thread implements KeyAgreementTask,
 				keyAgreementCrypto, payloadEncoder, transport, remotePayload,
 				localPayload, localKeyPair, alice);
 		try {
-			SecretKey master = protocol.perform();
+			SecretKey masterKey = protocol.perform();
 			KeyAgreementResult result =
-					new KeyAgreementResult(master, transport.getConnection(),
+					new KeyAgreementResult(masterKey, transport.getConnection(),
 							transport.getTransportId(), alice);
 			LOG.info("Finished BQP protocol");
 			// Broadcast result to caller

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

@@ -1,7 +1,7 @@
 package org.briarproject.bramble.plugin;
 
 import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.contact.event.ContactStatusChangedEvent;
+import org.briarproject.bramble.api.contact.event.ContactAddedEvent;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventListener;
@@ -80,12 +80,10 @@ class Poller implements EventListener {
 
 	@Override
 	public void eventOccurred(Event e) {
-		if (e instanceof ContactStatusChangedEvent) {
-			ContactStatusChangedEvent c = (ContactStatusChangedEvent) e;
-			if (c.isActive()) {
-				// Connect to the newly activated contact
-				connectToContact(c.getContactId());
-			}
+		if (e instanceof ContactAddedEvent) {
+			ContactAddedEvent c = (ContactAddedEvent) e;
+			// Connect to the newly activated contact
+			connectToContact(c.getContactId());
 		} else if (e instanceof ConnectionClosedEvent) {
 			ConnectionClosedEvent c = (ConnectionClosedEvent) e;
 			// Reschedule polling, the polling interval may have decreased

bramble-core/src/main/java/org/briarproject/bramble/plugin/tor/CircumventionProvider.java

@@ -17,16 +17,24 @@ public interface CircumventionProvider {
 	String[] BLOCKED = {"CN", "IR", "EG", "BY", "TR", "SY", "VE"};
 
 	/**
-	 * Countries where vanilla bridge connection are likely to work.
+	 * Countries where obfs4 bridge connection are likely to work.
 	 * Should be a subset of {@link #BLOCKED}.
 	 */
-	String[] BRIDGES = { "EG", "BY", "TR", "SY", "VE" };
+	String[] BRIDGES = { "CN", "IR", "EG", "BY", "TR", "SY", "VE" };
+
+	/**
+	 * Countries where obfs4 bridges won't work and meek is needed.
+	 * Should be a subset of {@link #BRIDGES}.
+	 */
+	String[] NEEDS_MEEK = {"CN", "IR"};
 
 	boolean isTorProbablyBlocked(String countryCode);
 
 	boolean doBridgesWork(String countryCode);
 
+	boolean needsMeek(String countryCode);
+
 	@IoExecutor
-	List<String> getBridges();
+	List<String> getBridges(boolean meek);
 
 }

bramble-core/src/main/java/org/briarproject/bramble/plugin/tor/CircumventionProviderImpl.java

@@ -22,6 +22,8 @@ class CircumventionProviderImpl implements CircumventionProvider {
 			new HashSet<>(asList(BLOCKED));
 	private static final Set<String> BRIDGES_WORK_IN_COUNTRIES =
 			new HashSet<>(asList(BRIDGES));
+	private static final Set<String> BRIDGES_NEED_MEEK =
+			new HashSet<>(asList(NEEDS_MEEK));
 
 	@Nullable
 	private volatile List<String> bridges = null;
@@ -40,9 +42,14 @@ class CircumventionProviderImpl implements CircumventionProvider {
 		return BRIDGES_WORK_IN_COUNTRIES.contains(countryCode);
 	}
 
+	@Override
+	public boolean needsMeek(String countryCode) {
+		return BRIDGES_NEED_MEEK.contains(countryCode);
+	}
+
 	@Override
 	@IoExecutor
-	public List<String> getBridges() {
+	public List<String> getBridges(boolean useMeek) {
 		List<String> bridges = this.bridges;
 		if (bridges != null) return new ArrayList<>(bridges);
 
@@ -53,6 +60,8 @@ class CircumventionProviderImpl implements CircumventionProvider {
 		bridges = new ArrayList<>();
 		while (scanner.hasNextLine()) {
 			String line = scanner.nextLine();
+			boolean isMeekBridge = line.startsWith("Bridge meek");
+			if (useMeek && !isMeekBridge || !useMeek && isMeekBridge) continue;
 			if (!line.startsWith("#")) bridges.add(line);
 		}
 		scanner.close();

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

@@ -69,6 +69,7 @@ import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_AUTOMATIC;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_NEVER;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_WITH_BRIDGES;
+import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_ONLY_WHEN_CHARGING;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_PORT;
 import static org.briarproject.bramble.api.plugin.TorConstants.PROP_ONION_V2;
 import static org.briarproject.bramble.api.plugin.TorConstants.PROP_ONION_V3;
@@ -469,13 +470,19 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		if (!enable) callback.transportDisabled();
 	}
 
-	private void enableBridges(boolean enable) throws IOException {
+	private void enableBridges(boolean enable, boolean needsMeek)
+			throws IOException {
 		if (enable) {
 			Collection<String> conf = new ArrayList<>();
 			conf.add("UseBridges 1");
-			conf.add("ClientTransportPlugin obfs4 exec " +
-					obfs4File.getAbsolutePath());
-			conf.addAll(circumventionProvider.getBridges());
+			if (needsMeek) {
+				conf.add("ClientTransportPlugin meek_lite exec " +
+						obfs4File.getAbsolutePath());
+			} else {
+				conf.add("ClientTransportPlugin obfs4 exec " +
+						obfs4File.getAbsolutePath());
+			}
+			conf.addAll(circumventionProvider.getBridges(needsMeek));
 			controlConnection.setConf(conf);
 		} else {
 			controlConnection.setConf("UseBridges", "0");
@@ -648,8 +655,10 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			if (s.getNamespace().equals(ID.getString())) {
 				LOG.info("Tor settings updated");
 				settings = s.getSettings();
-				// Works around a bug introduced in Tor 0.3.4.8. Could be
-				// replaced with callback.transportDisabled() when fixed.
+				// Works around a bug introduced in Tor 0.3.4.8.
+				// https://trac.torproject.org/projects/tor/ticket/28027
+				// Could be replaced with callback.transportDisabled()
+				// when fixed.
 				disableNetwork();
 				updateConnectionStatus(networkManager.getNetworkStatus(),
 						batteryManager.isCharging());
@@ -685,6 +694,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			int network = settings.getInt(PREF_TOR_NETWORK,
 					PREF_TOR_NETWORK_AUTOMATIC);
 			boolean useMobile = settings.getBoolean(PREF_TOR_MOBILE, true);
+			boolean onlyWhenCharging =
+					settings.getBoolean(PREF_TOR_ONLY_WHEN_CHARGING, false);
 			boolean bridgesWork = circumventionProvider.doBridgesWork(country);
 			boolean automatic = network == PREF_TOR_NETWORK_AUTOMATIC;
 
@@ -699,21 +710,29 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 				if (!online) {
 					LOG.info("Disabling network, device is offline");
 					enableNetwork(false);
+				} else if (!charging && onlyWhenCharging) {
+					LOG.info("Disabling network, device is on battery");
+					enableNetwork(false);
 				} else if (network == PREF_TOR_NETWORK_NEVER ||
 						(!useMobile && !wifi)) {
-					LOG.info("Disabling network due to setting");
+					LOG.info("Disabling network, device is using mobile data");
 					enableNetwork(false);
 				} else if (automatic && blocked && !bridgesWork) {
 					LOG.info("Disabling network, country is blocked");
 					enableNetwork(false);
 				} else if (network == PREF_TOR_NETWORK_WITH_BRIDGES ||
 						(automatic && bridgesWork)) {
-					LOG.info("Enabling network, using bridges");
-					enableBridges(true);
+					if (circumventionProvider.needsMeek(country)) {
+						LOG.info("Enabling network, using meek bridges");
+						enableBridges(true, true);
+					} else {
+						LOG.info("Enabling network, using obfs4 bridges");
+						enableBridges(true, false);
+					}
 					enableNetwork(true);
 				} else {
 					LOG.info("Enabling network, not using bridges");
-					enableBridges(false);
+					enableBridges(false, false);
 					enableNetwork(true);
 				}
 				if (online && wifi && charging) {

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

@@ -13,6 +13,8 @@ import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.properties.TransportProperties;
@@ -44,6 +46,7 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 
 	private final DatabaseComponent db;
 	private final ClientHelper clientHelper;
+	private final IdentityManager identityManager;
 	private final ClientVersioningManager clientVersioningManager;
 	private final MetadataParser metadataParser;
 	private final ContactGroupFactory contactGroupFactory;
@@ -53,11 +56,13 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	@Inject
 	TransportPropertyManagerImpl(DatabaseComponent db,
 			ClientHelper clientHelper,
+			IdentityManager identityManager,
 			ClientVersioningManager clientVersioningManager,
 			MetadataParser metadataParser,
 			ContactGroupFactory contactGroupFactory, Clock clock) {
 		this.db = db;
 		this.clientHelper = clientHelper;
+		this.identityManager = identityManager;
 		this.clientVersioningManager = clientVersioningManager;
 		this.metadataParser = metadataParser;
 		this.contactGroupFactory = contactGroupFactory;
@@ -77,7 +82,7 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	@Override
 	public void addingContact(Transaction txn, Contact c) throws DbException {
 		// Create a group to share with the contact
-		Group g = getContactGroup(c);
+		Group g = getContactGroup(c, getLocalAuthorId(txn));
 		db.addGroup(txn, g);
 		// Apply the client's visibility to the contact group
 		Visibility client = clientVersioningManager.getClientVisibility(txn,
@@ -93,14 +98,14 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 
 	@Override
 	public void removingContact(Transaction txn, Contact c) throws DbException {
-		db.removeGroup(txn, getContactGroup(c));
+		db.removeGroup(txn, getContactGroup(c, getLocalAuthorId(txn)));
 	}
 
 	@Override
 	public void onClientVisibilityChanging(Transaction txn, Contact c,
 			Visibility v) throws DbException {
 		// Apply the client's visibility to the contact group
-		Group g = getContactGroup(c);
+		Group g = getContactGroup(c, getLocalAuthorId(txn));
 		db.setGroupVisibility(txn, c.getId(), g.getId(), v);
 	}
 
@@ -132,7 +137,7 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	@Override
 	public void addRemoteProperties(Transaction txn, ContactId c,
 			Map<TransportId, TransportProperties> props) throws DbException {
-		Group g = getContactGroup(db.getContact(txn, c));
+		Group g = getContactGroup(db.getContact(txn, c), getLocalAuthorId(txn));
 		for (Entry<TransportId, TransportProperties> e : props.entrySet()) {
 			storeMessage(txn, g.getId(), e.getKey(), e.getValue(), 0,
 					false, false);
@@ -191,17 +196,16 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 			TransportId t) throws DbException {
 		return db.transactionWithResult(true, txn -> {
 			Map<ContactId, TransportProperties> remote = new HashMap<>();
+			AuthorId local = getLocalAuthorId(txn);
 			for (Contact c : db.getContacts(txn))
-				remote.put(c.getId(), getRemoteProperties(txn, c, t));
+				remote.put(c.getId(), getRemoteProperties(txn, c, local, t));
 			return remote;
 		});
 	}
 
 	private TransportProperties getRemoteProperties(Transaction txn, Contact c,
-			TransportId t) throws DbException {
-		// Don't return properties for inactive contacts
-		if (!c.isActive()) return new TransportProperties();
-		Group g = getContactGroup(c);
+			AuthorId local, TransportId t) throws DbException {
+		Group g = getContactGroup(c, local);
 		try {
 			// Find the latest remote update
 			LatestUpdate latest = findLatest(txn, g.getId(), t, false);
@@ -218,8 +222,11 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	@Override
 	public TransportProperties getRemoteProperties(ContactId c, TransportId t)
 			throws DbException {
-		return db.transactionWithResult(true, txn ->
-				getRemoteProperties(txn, db.getContact(txn, c), t));
+		return db.transactionWithResult(true, txn -> {
+			Contact contact = db.getContact(txn ,c);
+			AuthorId local = getLocalAuthorId(txn);
+			return getRemoteProperties(txn, contact, local, t);
+		});
 	}
 
 	@Override
@@ -252,8 +259,9 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 					if (latest != null)
 						db.removeMessage(txn, latest.messageId);
 					// Store the merged properties in each contact's group
+					AuthorId localAuthorId = getLocalAuthorId(txn);
 					for (Contact c : db.getContacts(txn)) {
-						Group g = getContactGroup(c);
+						Group g = getContactGroup(c, localAuthorId);
 						latest = findLatest(txn, g.getId(), t, true);
 						version = latest == null ? 1 : latest.version + 1;
 						storeMessage(txn, g.getId(), t, merged, version,
@@ -269,9 +277,13 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 		}
 	}
 
-	private Group getContactGroup(Contact c) {
+	private AuthorId getLocalAuthorId(Transaction txn) throws DbException {
+		return identityManager.getLocalAuthor(txn).getId();
+	}
+
+	private Group getContactGroup(Contact c, AuthorId local) {
 		return contactGroupFactory.createContactGroup(CLIENT_ID,
-				MAJOR_VERSION, c);
+				MAJOR_VERSION, c, local);
 	}
 
 	private void storeMessage(Transaction txn, GroupId g, TransportId t,

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

@@ -1,9 +1,7 @@
 package org.briarproject.bramble.transport;
 
-import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
-import org.briarproject.bramble.api.contact.event.ContactStatusChangedEvent;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
@@ -19,8 +17,8 @@ import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
 import org.briarproject.bramble.api.transport.KeyManager;
-import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.StreamContext;
+import org.briarproject.bramble.api.transport.TransportKeySetId;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -46,7 +44,6 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 	private final Executor dbExecutor;
 	private final PluginConfig pluginConfig;
 	private final TransportKeyManagerFactory transportKeyManagerFactory;
-	private final Map<ContactId, Boolean> activeContacts;
 	private final ConcurrentHashMap<TransportId, TransportKeyManager> managers;
 	private final AtomicBoolean used = new AtomicBoolean(false);
 
@@ -58,8 +55,6 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 		this.dbExecutor = dbExecutor;
 		this.pluginConfig = pluginConfig;
 		this.transportKeyManagerFactory = transportKeyManagerFactory;
-		// Use a ConcurrentHashMap as a thread-safe set
-		activeContacts = new ConcurrentHashMap<>();
 		managers = new ConcurrentHashMap<>();
 	}
 
@@ -73,8 +68,6 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 			transports.put(f.getId(), f.getMaxLatency());
 		try {
 			db.transaction(false, txn -> {
-				for (Contact c : db.getContacts(txn))
-					if (c.isActive()) activeContacts.put(c.getId(), true);
 				for (Entry<TransportId, Integer> e : transports.entrySet())
 					db.addTransport(txn, e.getKey(), e.getValue());
 				for (Entry<TransportId, Integer> e : transports.entrySet()) {
@@ -95,22 +88,22 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 	}
 
 	@Override
-	public Map<TransportId, KeySetId> addContact(Transaction txn, ContactId c,
-			SecretKey master, long timestamp, boolean alice, boolean active)
-			throws DbException {
-		Map<TransportId, KeySetId> ids = new HashMap<>();
+	public Map<TransportId, TransportKeySetId> addContact(Transaction txn,
+			ContactId c, SecretKey rootKey, long timestamp, boolean alice,
+			boolean active) throws DbException {
+		Map<TransportId, TransportKeySetId> ids = new HashMap<>();
 		for (Entry<TransportId, TransportKeyManager> e : managers.entrySet()) {
 			TransportId t = e.getKey();
 			TransportKeyManager m = e.getValue();
-			ids.put(t, m.addContact(txn, c, master, timestamp, alice, active));
+			ids.put(t, m.addContact(txn, c, rootKey, timestamp, alice, active));
 		}
 		return ids;
 	}
 
 	@Override
-	public void activateKeys(Transaction txn, Map<TransportId, KeySetId> keys)
-			throws DbException {
-		for (Entry<TransportId, KeySetId> e : keys.entrySet()) {
+	public void activateKeys(Transaction txn, Map<TransportId,
+			TransportKeySetId> keys) throws DbException {
+		for (Entry<TransportId, TransportKeySetId> e : keys.entrySet()) {
 			TransportId t = e.getKey();
 			TransportKeyManager m = managers.get(t);
 			if (m == null) {
@@ -130,8 +123,6 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 	@Override
 	public StreamContext getStreamContext(ContactId c, TransportId t)
 			throws DbException {
-		// Don't allow outgoing streams to inactive contacts
-		if (!activeContacts.containsKey(c)) return null;
 		TransportKeyManager m = managers.get(t);
 		if (m == null) {
 			if (LOG.isLoggable(INFO)) LOG.info("No key manager for " + t);
@@ -157,15 +148,10 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 	public void eventOccurred(Event e) {
 		if (e instanceof ContactRemovedEvent) {
 			removeContact(((ContactRemovedEvent) e).getContactId());
-		} else if (e instanceof ContactStatusChangedEvent) {
-			ContactStatusChangedEvent c = (ContactStatusChangedEvent) e;
-			if (c.isActive()) activeContacts.put(c.getContactId(), true);
-			else activeContacts.remove(c.getContactId());
 		}
 	}
 
 	private void removeContact(ContactId c) {
-		activeContacts.remove(c);
 		dbExecutor.execute(() -> {
 			for (TransportKeyManager m : managers.values()) m.removeContact(c);
 		});

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

@@ -11,18 +11,18 @@ import javax.annotation.concurrent.NotThreadSafe;
 class MutableIncomingKeys {
 
 	private final SecretKey tagKey, headerKey;
-	private final long rotationPeriod;
+	private final long timePeriod;
 	private final ReorderingWindow window;
 
 	MutableIncomingKeys(IncomingKeys in) {
 		tagKey = in.getTagKey();
 		headerKey = in.getHeaderKey();
-		rotationPeriod = in.getRotationPeriod();
+		timePeriod = in.getTimePeriod();
 		window = new ReorderingWindow(in.getWindowBase(), in.getWindowBitmap());
 	}
 
 	IncomingKeys snapshot() {
-		return new IncomingKeys(tagKey, headerKey, rotationPeriod,
+		return new IncomingKeys(tagKey, headerKey, timePeriod,
 				window.getBase(), window.getBitmap());
 	}
 
@@ -34,8 +34,8 @@ class MutableIncomingKeys {
 		return headerKey;
 	}
 
-	long getRotationPeriod() {
-		return rotationPeriod;
+	long getTimePeriod() {
+		return timePeriod;
 	}
 
 	ReorderingWindow getWindow() {

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

@@ -1,22 +1,22 @@
 package org.briarproject.bramble.transport;
 
 import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.transport.KeySetId;
+import org.briarproject.bramble.api.transport.TransportKeySetId;
 
 class MutableKeySet {
 
-	private final KeySetId keySetId;
+	private final TransportKeySetId keySetId;
 	private final ContactId contactId;
 	private final MutableTransportKeys transportKeys;
 
-	MutableKeySet(KeySetId keySetId, ContactId contactId,
+	MutableKeySet(TransportKeySetId keySetId, ContactId contactId,
 			MutableTransportKeys transportKeys) {
 		this.keySetId = keySetId;
 		this.contactId = contactId;
 		this.transportKeys = transportKeys;
 	}
 
-	KeySetId getKeySetId() {
+	TransportKeySetId getKeySetId() {
 		return keySetId;
 	}
 

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

@@ -11,20 +11,20 @@ import javax.annotation.concurrent.NotThreadSafe;
 class MutableOutgoingKeys {
 
 	private final SecretKey tagKey, headerKey;
-	private final long rotationPeriod;
+	private final long timePeriod;
 	private long streamCounter;
 	private boolean active;
 
 	MutableOutgoingKeys(OutgoingKeys out) {
 		tagKey = out.getTagKey();
 		headerKey = out.getHeaderKey();
-		rotationPeriod = out.getRotationPeriod();
+		timePeriod = out.getTimePeriod();
 		streamCounter = out.getStreamCounter();
 		active = out.isActive();
 	}
 
 	OutgoingKeys snapshot() {
-		return new OutgoingKeys(tagKey, headerKey, rotationPeriod,
+		return new OutgoingKeys(tagKey, headerKey, timePeriod,
 				streamCounter, active);
 	}
 
@@ -36,8 +36,8 @@ class MutableOutgoingKeys {
 		return headerKey;
 	}
 
-	long getRotationPeriod() {
-		return rotationPeriod;
+	long getTimePeriod() {
+		return timePeriod;
 	}
 
 	long getStreamCounter() {

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

@@ -5,8 +5,8 @@ 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.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.StreamContext;
+import org.briarproject.bramble.api.transport.TransportKeySetId;
 
 import javax.annotation.Nullable;
 
@@ -15,10 +15,11 @@ interface TransportKeyManager {
 
 	void start(Transaction txn) throws DbException;
 
-	KeySetId addContact(Transaction txn, ContactId c, SecretKey master,
-			long timestamp, boolean alice, boolean active) throws DbException;
+	TransportKeySetId addContact(Transaction txn, ContactId c,
+			SecretKey rootKey, long timestamp, boolean alice, boolean active)
+			throws DbException;
 
-	void activateKeys(Transaction txn, KeySetId k) throws DbException;
+	void activateKeys(Transaction txn, TransportKeySetId k) throws DbException;
 
 	void removeContact(ContactId c);
 

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

@@ -11,9 +11,9 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.Scheduler;
-import org.briarproject.bramble.api.transport.KeySet;
-import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.StreamContext;
+import org.briarproject.bramble.api.transport.TransportKeySet;
+import org.briarproject.bramble.api.transport.TransportKeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
 import org.briarproject.bramble.transport.ReorderingWindow.Change;
 
@@ -51,12 +51,12 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 	private final ScheduledExecutorService scheduler;
 	private final Clock clock;
 	private final TransportId transportId;
-	private final long rotationPeriodLength;
+	private final long timePeriodLength;
 	private final AtomicBoolean used = new AtomicBoolean(false);
 	private final ReentrantLock lock = new ReentrantLock();
 
 	// The following are locking: lock
-	private final Map<KeySetId, MutableKeySet> keys = new HashMap<>();
+	private final Map<TransportKeySetId, MutableKeySet> keys = new HashMap<>();
 	private final Map<Bytes, TagContext> inContexts = new HashMap<>();
 	private final Map<ContactId, MutableKeySet> outContexts = new HashMap<>();
 
@@ -70,7 +70,7 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 		this.scheduler = scheduler;
 		this.clock = clock;
 		this.transportId = transportId;
-		rotationPeriodLength = maxLatency + MAX_CLOCK_DIFFERENCE;
+		timePeriodLength = maxLatency + MAX_CLOCK_DIFFERENCE;
 	}
 
 	@Override
@@ -80,8 +80,9 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 		lock.lock();
 		try {
 			// Load the transport keys from the DB
-			Collection<KeySet> loaded = db.getTransportKeys(txn, transportId);
-			// Rotate the keys to the current rotation period
+			Collection<TransportKeySet> loaded =
+					db.getTransportKeys(txn, transportId);
+			// Rotate the keys to the current time period
 			RotationResult rotationResult = rotateKeys(loaded, now);
 			// Initialise mutable state for all contacts
 			addKeys(rotationResult.current);
@@ -95,15 +96,17 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 		scheduleKeyRotation(now);
 	}
 
-	private RotationResult rotateKeys(Collection<KeySet> keys, long now) {
+	private RotationResult rotateKeys(Collection<TransportKeySet> keys,
+			long now) {
 		RotationResult rotationResult = new RotationResult();
-		long rotationPeriod = now / rotationPeriodLength;
-		for (KeySet ks : keys) {
-			TransportKeys k = ks.getTransportKeys();
-			TransportKeys k1 =
-					transportCrypto.rotateTransportKeys(k, rotationPeriod);
-			KeySet ks1 = new KeySet(ks.getKeySetId(), ks.getContactId(), k1);
-			if (k1.getRotationPeriod() > k.getRotationPeriod())
+		long timePeriod = now / timePeriodLength;
+		for (TransportKeySet ks : keys) {
+			TransportKeys k = ks.getKeys();
+			TransportKeys k1 = transportCrypto.rotateTransportKeys(k,
+					timePeriod);
+			TransportKeySet ks1 = new TransportKeySet(ks.getKeySetId(),
+					ks.getContactId(), k1);
+			if (k1.getTimePeriod() > k.getTimePeriod())
 				rotationResult.rotated.add(ks1);
 			rotationResult.current.add(ks1);
 		}
@@ -111,15 +114,15 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 	}
 
 	// Locking: lock
-	private void addKeys(Collection<KeySet> keys) {
-		for (KeySet ks : keys) {
+	private void addKeys(Collection<TransportKeySet> keys) {
+		for (TransportKeySet ks : keys) {
 			addKeys(ks.getKeySetId(), ks.getContactId(),
-					new MutableTransportKeys(ks.getTransportKeys()));
+					new MutableTransportKeys(ks.getKeys()));
 		}
 	}
 
 	// Locking: lock
-	private void addKeys(KeySetId keySetId, ContactId contactId,
+	private void addKeys(TransportKeySetId keySetId, ContactId contactId,
 			MutableTransportKeys m) {
 		MutableKeySet ks = new MutableKeySet(keySetId, contactId, m);
 		keys.put(keySetId, ks);
@@ -130,7 +133,7 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 	}
 
 	// Locking: lock
-	private void encodeTags(KeySetId keySetId, ContactId contactId,
+	private void encodeTags(TransportKeySetId keySetId, ContactId contactId,
 			MutableIncomingKeys inKeys) {
 		for (long streamNumber : inKeys.getWindow().getUnseen()) {
 			TagContext tagCtx =
@@ -155,7 +158,7 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 	}
 
 	private void scheduleKeyRotation(long now) {
-		long delay = rotationPeriodLength - now % rotationPeriodLength;
+		long delay = timePeriodLength - now % timePeriodLength;
 		scheduler.schedule((Runnable) this::rotateKeys, delay, MILLISECONDS);
 	}
 
@@ -170,20 +173,21 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 	}
 
 	@Override
-	public KeySetId addContact(Transaction txn, ContactId c, SecretKey master,
-			long timestamp, boolean alice, boolean active) throws DbException {
+	public TransportKeySetId addContact(Transaction txn, ContactId c,
+			SecretKey rootKey, long timestamp, boolean alice, boolean active)
+			throws DbException {
 		lock.lock();
 		try {
-			// Work out what rotation period the timestamp belongs to
-			long rotationPeriod = timestamp / rotationPeriodLength;
+			// Work out what time period the timestamp belongs to
+			long timePeriod = timestamp / timePeriodLength;
 			// Derive the transport keys
 			TransportKeys k = transportCrypto.deriveTransportKeys(transportId,
-					master, rotationPeriod, alice, active);
-			// Rotate the keys to the current rotation period if necessary
-			rotationPeriod = clock.currentTimeMillis() / rotationPeriodLength;
-			k = transportCrypto.rotateTransportKeys(k, rotationPeriod);
+					rootKey, timePeriod, alice, active);
+			// Rotate the keys to the current time period if necessary
+			timePeriod = clock.currentTimeMillis() / timePeriodLength;
+			k = transportCrypto.rotateTransportKeys(k, timePeriod);
 			// Write the keys back to the DB
-			KeySetId keySetId = db.addTransportKeys(txn, c, k);
+			TransportKeySetId keySetId = db.addTransportKeys(txn, c, k);
 			// Initialise mutable state for the contact
 			addKeys(keySetId, c, new MutableTransportKeys(k));
 			return keySetId;
@@ -193,7 +197,8 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 	}
 
 	@Override
-	public void activateKeys(Transaction txn, KeySetId k) throws DbException {
+	public void activateKeys(Transaction txn, TransportKeySetId k)
+			throws DbException {
 		lock.lock();
 		try {
 			MutableKeySet ks = keys.get(k);
@@ -300,7 +305,7 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 			}
 			// Write the window back to the DB
 			db.setReorderingWindow(txn, tagCtx.keySetId, transportId,
-					inKeys.getRotationPeriod(), window.getBase(),
+					inKeys.getTimePeriod(), window.getBase(),
 					window.getBitmap());
 			// If the outgoing keys are inactive, activate them
 			MutableKeySet ks = keys.get(tagCtx.keySetId);
@@ -322,11 +327,11 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 		long now = clock.currentTimeMillis();
 		lock.lock();
 		try {
-			// Rotate the keys to the current rotation period
-			Collection<KeySet> snapshot = new ArrayList<>(keys.size());
+			// Rotate the keys to the current time period
+			Collection<TransportKeySet> snapshot = new ArrayList<>(keys.size());
 			for (MutableKeySet ks : keys.values()) {
-				snapshot.add(new KeySet(ks.getKeySetId(), ks.getContactId(),
-						ks.getTransportKeys().snapshot()));
+				snapshot.add(new TransportKeySet(ks.getKeySetId(),
+						ks.getContactId(), ks.getTransportKeys().snapshot()));
 			}
 			RotationResult rotationResult = rotateKeys(snapshot, now);
 			// Rebuild the mutable state for all contacts
@@ -346,12 +351,12 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 
 	private static class TagContext {
 
-		private final KeySetId keySetId;
+		private final TransportKeySetId keySetId;
 		private final ContactId contactId;
 		private final MutableIncomingKeys inKeys;
 		private final long streamNumber;
 
-		private TagContext(KeySetId keySetId, ContactId contactId,
+		private TagContext(TransportKeySetId keySetId, ContactId contactId,
 				MutableIncomingKeys inKeys, long streamNumber) {
 			this.keySetId = keySetId;
 			this.contactId = contactId;
@@ -362,7 +367,7 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 
 	private static class RotationResult {
 
-		private final Collection<KeySet> current = new ArrayList<>();
-		private final Collection<KeySet> rotated = new ArrayList<>();
+		private final Collection<TransportKeySet> current = new ArrayList<>();
+		private final Collection<TransportKeySet> rotated = new ArrayList<>();
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/versioning/ClientVersioningManagerImpl.java

@@ -12,6 +12,8 @@ import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.lifecycle.Service;
 import org.briarproject.bramble.api.lifecycle.ServiceException;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
@@ -58,6 +60,7 @@ class ClientVersioningManagerImpl implements ClientVersioningManager, Client,
 
 	private final DatabaseComponent db;
 	private final ClientHelper clientHelper;
+	private final IdentityManager identityManager;
 	private final ContactGroupFactory contactGroupFactory;
 	private final Clock clock;
 	private final Group localGroup;
@@ -68,9 +71,11 @@ class ClientVersioningManagerImpl implements ClientVersioningManager, Client,
 
 	@Inject
 	ClientVersioningManagerImpl(DatabaseComponent db, ClientHelper clientHelper,
+			IdentityManager identityManager,
 			ContactGroupFactory contactGroupFactory, Clock clock) {
 		this.db = db;
 		this.clientHelper = clientHelper;
+		this.identityManager = identityManager;
 		this.contactGroupFactory = contactGroupFactory;
 		this.clock = clock;
 		localGroup = contactGroupFactory.createLocalGroup(CLIENT_ID,
@@ -89,14 +94,9 @@ class ClientVersioningManagerImpl implements ClientVersioningManager, Client,
 	public Visibility getClientVisibility(Transaction txn, ContactId contactId,
 			ClientId clientId, int majorVersion) throws DbException {
 		try {
-			Contact contact = db.getContact(txn, contactId);
-			Group g = getContactGroup(contact);
-			// Contact may be in the process of being added or removed, so
-			// contact group may not exist
-			if (!db.containsGroup(txn, g.getId())) return INVISIBLE;
-			LatestUpdates latest = findLatestUpdates(txn, g.getId());
+			LatestUpdates latest = findLatestUpdates(txn, contactId);
+			if (latest == null || latest.remote == null) return INVISIBLE;
 			if (latest.local == null) throw new DbException();
-			if (latest.remote == null) return INVISIBLE;
 			Update localUpdate = loadUpdate(txn, latest.local.messageId);
 			Update remoteUpdate = loadUpdate(txn, latest.remote.messageId);
 			Map<ClientMajorVersion, Visibility> visibilities =
@@ -110,6 +110,24 @@ class ClientVersioningManagerImpl implements ClientVersioningManager, Client,
 		}
 	}
 
+	@Override
+	public int getClientMinorVersion(Transaction txn, ContactId contactId,
+			ClientId clientId, int majorVersion) throws DbException {
+		try {
+			LatestUpdates latest = findLatestUpdates(txn, contactId);
+			if (latest == null || latest.remote == null) return -1;
+			Update remoteUpdate = loadUpdate(txn, latest.remote.messageId);
+			ClientMajorVersion cv =
+					new ClientMajorVersion(clientId, majorVersion);
+			for (ClientState remote : remoteUpdate.states) {
+				if (remote.majorVersion.equals(cv)) return remote.minorVersion;
+			}
+			return -1;
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	public void createLocalState(Transaction txn) throws DbException {
 		if (db.containsGroup(txn, localGroup.getId())) return;
@@ -141,7 +159,7 @@ class ClientVersioningManagerImpl implements ClientVersioningManager, Client,
 	@Override
 	public void addingContact(Transaction txn, Contact c) throws DbException {
 		// Create a group and share it with the contact
-		Group g = getContactGroup(c);
+		Group g = getContactGroup(c, getLocalAuthorId(txn));
 		db.addGroup(txn, g);
 		db.setGroupVisibility(txn, c.getId(), g.getId(), SHARED);
 		// Attach the contact ID to the group
@@ -160,7 +178,7 @@ class ClientVersioningManagerImpl implements ClientVersioningManager, Client,
 
 	@Override
 	public void removingContact(Transaction txn, Contact c) throws DbException {
-		db.removeGroup(txn, getContactGroup(c));
+		db.removeGroup(txn, getContactGroup(c, getLocalAuthorId(txn)));
 	}
 
 	@Override
@@ -295,7 +313,7 @@ class ClientVersioningManagerImpl implements ClientVersioningManager, Client,
 			List<ClientVersion> versions) throws DbException {
 		try {
 			// Find the latest local and remote updates
-			Group g = getContactGroup(c);
+			Group g = getContactGroup(c, getLocalAuthorId(txn));
 			LatestUpdates latest = findLatestUpdates(txn, g.getId());
 			// Load and parse the latest local update
 			if (latest.local == null) throw new DbException();
@@ -331,9 +349,24 @@ class ClientVersioningManagerImpl implements ClientVersioningManager, Client,
 		}
 	}
 
-	private Group getContactGroup(Contact c) {
+	private AuthorId getLocalAuthorId(Transaction txn) throws DbException {
+		return identityManager.getLocalAuthor(txn).getId();
+	}
+
+	private Group getContactGroup(Contact c, AuthorId local) {
 		return contactGroupFactory.createContactGroup(CLIENT_ID,
-				MAJOR_VERSION, c);
+				MAJOR_VERSION, c, local);
+	}
+
+	@Nullable
+	private LatestUpdates findLatestUpdates(Transaction txn, ContactId c)
+			throws DbException, FormatException {
+		Contact contact = db.getContact(txn, c);
+		Group g = getContactGroup(contact, getLocalAuthorId(txn));
+		// Contact may be in the process of being added or removed, so
+		// contact group may not exist
+		if (!db.containsGroup(txn, g.getId())) return null;
+		return findLatestUpdates(txn, g.getId());
 	}
 
 	private LatestUpdates findLatestUpdates(Transaction txn, GroupId g)

bramble-core/src/main/resources/bridges

@@ -1,4 +1,5 @@
 Bridge obfs4 78.46.188.239:37356 5A2D2F4158D0453E00C7C176978D3F41D69C45DB cert=3c0SwxpOisbohNxEc4tb875RVW8eOu1opRTVXJhafaKA/PNNtI7ElQIVOVZg1AdL5bxGCw iat-mode=0
 Bridge obfs4 52.15.78.72:9443 02069A3C5362476936B62BA6F5ACC41ABD573A9B cert=ijYG/OKc7kqu2YzKNFfeXN7/BG2BOgfEP2KyYEiGDQthnHbsOiTWHeIG0WJVW+BckzDgKw iat-mode=0
 Bridge obfs4 13.58.29.242:9443 0C58939A77DA6B6B29D4B5236A75865659607AE0 cert=OylWIEHb/ezpq1zWxW0sgKRn+9ARH2eOcQOZ8/Gew+4l+oKOhQ2jUX/Y+FSl61JorXZUWA iat-mode=0
-Bridge obfs4 45.33.37.112:9443 60A609BB4ABE8D46E634AE81ED29ADAB7776B399 cert=t5v19WmNv5Sc2YPNr8RQids365W7MY8zJwQVkOxBjUMFomMWARDzsbYpcWLLcw0J9Gm+BQ iat-mode=0
+Bridge obfs4 45.33.37.112:9443 60A609BB4ABE8D46E634AE81ED29ADAB7776B399 cert=t5v19WmNv5Sc2YPNr8RQids365W7MY8zJwQVkOxBjUMFomMWARDzsbYpcWLLcw0J9Gm+BQ iat-mode=0
+Bridge meek_lite 0.0.2.0:2 97700DFE9F483596DDA6264C4D7DF7641E1E39CE url=https://meek.azureedge.net/ front=ajax.aspnetcdn.com

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

@@ -5,27 +5,20 @@ import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
 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.NoSuchContactException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
-import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.identity.AuthorInfo;
 import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.transport.KeyManager;
 import org.briarproject.bramble.test.BrambleMockTestCase;
 import org.briarproject.bramble.test.DbExpectations;
-import org.jmock.Expectations;
 import org.jmock.Mockery;
 import org.junit.Test;
 
-import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.Random;
 
-import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorInfo.Status.OURSELVES;
@@ -33,8 +26,8 @@ import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNKNOWN;
 import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNVERIFIED;
 import static org.briarproject.bramble.api.identity.AuthorInfo.Status.VERIFIED;
 import static org.briarproject.bramble.test.TestUtils.getAuthor;
+import static org.briarproject.bramble.test.TestUtils.getContact;
 import static org.briarproject.bramble.test.TestUtils.getLocalAuthor;
-import static org.briarproject.bramble.test.TestUtils.getRandomId;
 import static org.briarproject.bramble.test.TestUtils.getSecretKey;
 import static org.briarproject.bramble.util.StringUtils.getRandomString;
 import static org.junit.Assert.assertEquals;
@@ -49,42 +42,40 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	private final IdentityManager identityManager =
 			context.mock(IdentityManager.class);
 	private final ContactManager contactManager;
-	private final ContactId contactId = new ContactId(42);
-	private final Author remote = getAuthor();
-	private final AuthorId local = new AuthorId(getRandomId());
+	private final Author author = getAuthor();
 	private final LocalAuthor localAuthor = getLocalAuthor();
-	private final String alias = getRandomString(MAX_AUTHOR_NAME_LENGTH);
 	private final boolean verified = false, active = true;
-	private final Contact contact =
-			new Contact(contactId, remote, local, alias, verified, active);
+	private final Contact contact = getContact(author, verified);
+	private final ContactId contactId = contact.getId();
 
 	public ContactManagerImplTest() {
-		contactManager = new ContactManagerImpl(db, keyManager, identityManager);
+		contactManager =
+				new ContactManagerImpl(db, keyManager, identityManager);
 	}
 
 	@Test
 	public void testAddContact() throws Exception {
-		SecretKey master = getSecretKey();
+		SecretKey rootKey = getSecretKey();
 		long timestamp = System.currentTimeMillis();
 		boolean alice = new Random().nextBoolean();
 		Transaction txn = new Transaction(null, false);
 
 		context.checking(new DbExpectations() {{
 			oneOf(db).transactionWithResult(with(false), withDbCallable(txn));
-			oneOf(db).addContact(txn, remote, local, verified, active);
+			oneOf(db).addContact(txn, author, verified);
 			will(returnValue(contactId));
-			oneOf(keyManager).addContact(txn, contactId, master, timestamp,
+			oneOf(keyManager).addContact(txn, contactId, rootKey, timestamp,
 					alice, active);
 			oneOf(db).getContact(txn, contactId);
 			will(returnValue(contact));
 		}});
 
-		assertEquals(contactId, contactManager.addContact(remote, local,
-				master, timestamp, alice, verified, active));
+		assertEquals(contactId, contactManager.addContact(author, rootKey,
+				timestamp, alice, verified, active));
 	}
 
 	@Test
-	public void testGetContact() throws Exception {
+	public void testGetContactByContactId() throws Exception {
 		Transaction txn = new Transaction(null, true);
 		context.checking(new DbExpectations() {{
 			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
@@ -96,49 +87,20 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	}
 
 	@Test
-	public void testGetContactByAuthor() throws Exception {
-		Transaction txn = new Transaction(null, true);
-		Collection<Contact> contacts = Collections.singleton(contact);
-		context.checking(new DbExpectations() {{
-			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			oneOf(db).getContactsByAuthorId(txn, remote.getId());
-			will(returnValue(contacts));
-		}});
-
-		assertEquals(contact, contactManager.getContact(remote.getId(), local));
-	}
-
-	@Test(expected = NoSuchContactException.class)
-	public void testGetContactByUnknownAuthor() throws Exception {
+	public void testGetContactByAuthorId() throws Exception {
 		Transaction txn = new Transaction(null, true);
 		context.checking(new DbExpectations() {{
 			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			oneOf(db).getContactsByAuthorId(txn, remote.getId());
-			will(returnValue(emptyList()));
+			oneOf(db).getContact(txn, author.getId());
+			will(returnValue(contact));
 		}});
 
-		contactManager.getContact(remote.getId(), local);
-	}
-
-	@Test(expected = NoSuchContactException.class)
-	public void testGetContactByUnknownLocalAuthor() throws Exception {
-		Transaction txn = new Transaction(null, true);
-		Collection<Contact> contacts = Collections.singleton(contact);
-		context.checking(new DbExpectations() {{
-			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			oneOf(db).getContactsByAuthorId(txn, remote.getId());
-			will(returnValue(contacts));
-		}});
-
-		contactManager.getContact(remote.getId(), new AuthorId(getRandomId()));
+		assertEquals(contact, contactManager.getContact(author.getId()));
 	}
 
 	@Test
-	public void testGetActiveContacts() throws Exception {
-		Collection<Contact> activeContacts = Collections.singletonList(contact);
-		Collection<Contact> contacts = new ArrayList<>(activeContacts);
-		contacts.add(new Contact(new ContactId(3), remote, local, alias, true,
-				false));
+	public void testGetContacts() throws Exception {
+		Collection<Contact> contacts = singletonList(contact);
 		Transaction txn = new Transaction(null, true);
 		context.checking(new DbExpectations() {{
 			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
@@ -146,7 +108,7 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 			will(returnValue(contacts));
 		}});
 
-		assertEquals(activeContacts, contactManager.getActiveContacts());
+		assertEquals(contacts, contactManager.getContacts());
 	}
 
 	@Test
@@ -162,19 +124,11 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 		contactManager.removeContact(contactId);
 	}
 
-	@Test
-	public void testSetContactActive() throws Exception {
-		Transaction txn = new Transaction(null, false);
-		context.checking(new Expectations() {{
-			oneOf(db).setContactActive(txn, contactId, active);
-		}});
-
-		contactManager.setContactActive(txn, contactId, active);
-	}
-
 	@Test
 	public void testSetContactAlias() throws Exception {
 		Transaction txn = new Transaction(null, false);
+		String alias = getRandomString(MAX_AUTHOR_NAME_LENGTH);
+
 		context.checking(new DbExpectations() {{
 			oneOf(db).transaction(with(false), withDbRunnable(txn));
 			oneOf(db).setContactAlias(txn, contactId, alias);
@@ -195,85 +149,82 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 		Transaction txn = new Transaction(null, true);
 		context.checking(new DbExpectations() {{
 			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			oneOf(db).containsContact(txn, remote.getId(), local);
+			oneOf(db).containsContact(txn, author.getId());
 			will(returnValue(true));
 		}});
 
-		assertTrue(contactManager.contactExists(remote.getId(), local));
+		assertTrue(contactManager.contactExists(author.getId()));
 	}
 
 	@Test
-	public void testGetAuthorInfo() throws Exception {
+	public void testGetAuthorInfoOurselves() throws Exception {
 		Transaction txn = new Transaction(null, true);
-		Collection<Contact> contacts = singletonList(
-				new Contact(new ContactId(1), remote, localAuthor.getId(),
-						alias, false, true));
 
 		context.checking(new DbExpectations() {{
 			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
 			oneOf(identityManager).getLocalAuthor(txn);
 			will(returnValue(localAuthor));
-			oneOf(db).getContactsByAuthorId(txn, remote.getId());
-			will(returnValue(contacts));
 		}});
 		AuthorInfo authorInfo =
-				contactManager.getAuthorInfo(txn, remote.getId());
-		assertEquals(UNVERIFIED, authorInfo.getStatus());
-		assertEquals(alias, contact.getAlias());
-	}
-
-	@Test
-	public void testGetAuthorInfoTransaction() throws DbException {
-		Transaction txn = new Transaction(null, true);
-
-		// check unknown author
-		context.checking(new Expectations() {{
-			oneOf(identityManager).getLocalAuthor(txn);
-			will(returnValue(localAuthor));
-			oneOf(db).getContactsByAuthorId(txn, remote.getId());
-			will(returnValue(emptyList()));
-		}});
-		AuthorInfo authorInfo =
-				contactManager.getAuthorInfo(txn, remote.getId());
-		assertEquals(UNKNOWN, authorInfo.getStatus());
-		assertNull(authorInfo.getAlias());
-
-		// check unverified contact
-		Collection<Contact> contacts = singletonList(
-				new Contact(new ContactId(1), remote, localAuthor.getId(),
-						alias, false, true));
-		checkAuthorInfoContext(txn, remote.getId(), contacts);
-		authorInfo = contactManager.getAuthorInfo(txn, remote.getId());
-		assertEquals(UNVERIFIED, authorInfo.getStatus());
-		assertEquals(alias, contact.getAlias());
-
-		// check verified contact
-		contacts = singletonList(new Contact(new ContactId(1), remote,
-				localAuthor.getId(), alias, true, true));
-		checkAuthorInfoContext(txn, remote.getId(), contacts);
-		authorInfo = contactManager.getAuthorInfo(txn, remote.getId());
-		assertEquals(VERIFIED, authorInfo.getStatus());
-		assertEquals(alias, contact.getAlias());
-
-		// check ourselves
-		context.checking(new Expectations() {{
-			oneOf(identityManager).getLocalAuthor(txn);
-			will(returnValue(localAuthor));
-			never(db).getContactsByAuthorId(txn, remote.getId());
-		}});
-		authorInfo = contactManager.getAuthorInfo(txn, localAuthor.getId());
+				contactManager.getAuthorInfo(txn, localAuthor.getId());
 		assertEquals(OURSELVES, authorInfo.getStatus());
 		assertNull(authorInfo.getAlias());
 	}
 
-	private void checkAuthorInfoContext(Transaction txn, AuthorId authorId,
-			Collection<Contact> contacts) throws DbException {
-		context.checking(new Expectations() {{
+	@Test
+	public void testGetAuthorInfoVerified() throws Exception {
+		Transaction txn = new Transaction(null, true);
+		Contact verified = getContact(author, true);
+
+		context.checking(new DbExpectations() {{
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
 			oneOf(identityManager).getLocalAuthor(txn);
 			will(returnValue(localAuthor));
-			oneOf(db).getContactsByAuthorId(txn, authorId);
-			will(returnValue(contacts));
+			oneOf(db).containsContact(txn, author.getId());
+			will(returnValue(true));
+			oneOf(db).getContact(txn, author.getId());
+			will(returnValue(verified));
 		}});
+		AuthorInfo authorInfo =
+				contactManager.getAuthorInfo(txn, author.getId());
+		assertEquals(VERIFIED, authorInfo.getStatus());
+		assertEquals(verified.getAlias(), authorInfo.getAlias());
 	}
 
+	@Test
+	public void testGetAuthorInfoUnverified() throws Exception {
+		Transaction txn = new Transaction(null, true);
+		Contact unverified = getContact(author, false);
+
+		context.checking(new DbExpectations() {{
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
+			oneOf(db).containsContact(txn, author.getId());
+			will(returnValue(true));
+			oneOf(db).getContact(txn, author.getId());
+			will(returnValue(unverified));
+		}});
+		AuthorInfo authorInfo =
+				contactManager.getAuthorInfo(txn, author.getId());
+		assertEquals(UNVERIFIED, authorInfo.getStatus());
+		assertEquals(unverified.getAlias(), authorInfo.getAlias());
+	}
+
+	@Test
+	public void testGetAuthorInfoUnknown() throws Exception {
+		Transaction txn = new Transaction(null, true);
+
+		context.checking(new DbExpectations() {{
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
+			oneOf(db).containsContact(txn, author.getId());
+			will(returnValue(false));
+		}});
+		AuthorInfo authorInfo =
+				contactManager.getAuthorInfo(txn, author.getId());
+		assertEquals(UNKNOWN, authorInfo.getStatus());
+		assertNull(authorInfo.getAlias());
+	}
 }

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

@@ -0,0 +1,167 @@
+package org.briarproject.bramble.crypto;
+
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.crypto.TransportCrypto;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.transport.HandshakeKeys;
+import org.briarproject.bramble.test.BrambleTestCase;
+import org.briarproject.bramble.test.TestSecureRandomProvider;
+import org.junit.Test;
+
+import java.util.Arrays;
+
+import static org.briarproject.bramble.crypto.KeyDerivationTestUtils.assertAllDifferent;
+import static org.briarproject.bramble.crypto.KeyDerivationTestUtils.assertMatches;
+import static org.briarproject.bramble.test.TestUtils.getSecretKey;
+import static org.briarproject.bramble.test.TestUtils.getTransportId;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertSame;
+
+public class HandshakeKeyDerivationTest extends BrambleTestCase {
+
+	private final CryptoComponent crypto =
+			new CryptoComponentImpl(new TestSecureRandomProvider(), null);
+	private final TransportCrypto transportCrypto =
+			new TransportCryptoImpl(crypto);
+	private final TransportId transportId = getTransportId();
+	private final SecretKey rootKey = getSecretKey();
+
+	@Test
+	public void testKeysAreDistinct() {
+		HandshakeKeys kA = transportCrypto.deriveHandshakeKeys(transportId,
+				rootKey, 123, true);
+		HandshakeKeys kB = transportCrypto.deriveHandshakeKeys(transportId,
+				rootKey, 123, false);
+		assertAllDifferent(kA);
+		assertAllDifferent(kB);
+	}
+
+	@Test
+	public void testKeysAreNotUpdatedToPreviousPeriod() {
+		HandshakeKeys k = transportCrypto.deriveHandshakeKeys(transportId,
+				rootKey, 123, true);
+		HandshakeKeys k1 = transportCrypto.updateHandshakeKeys(k, 122);
+		assertSame(k, k1);
+	}
+
+	@Test
+	public void testKeysAreNotUpdatedToCurrentPeriod() {
+		HandshakeKeys k = transportCrypto.deriveHandshakeKeys(transportId,
+				rootKey, 123, true);
+		HandshakeKeys k1 = transportCrypto.updateHandshakeKeys(k, 123);
+		assertSame(k, k1);
+	}
+
+	@Test
+	public void testKeysAreUpdatedByOnePeriod() {
+		HandshakeKeys k = transportCrypto.deriveHandshakeKeys(transportId,
+				rootKey, 123, true);
+		HandshakeKeys k1 = transportCrypto.updateHandshakeKeys(k, 124);
+		assertSame(k.getCurrentIncomingKeys(), k1.getPreviousIncomingKeys());
+		assertSame(k.getNextIncomingKeys(), k1.getCurrentIncomingKeys());
+	}
+
+	@Test
+	public void testKeysAreUpdatedByTwoPeriods() {
+		HandshakeKeys k = transportCrypto.deriveHandshakeKeys(transportId,
+				rootKey, 123, true);
+		HandshakeKeys k1 = transportCrypto.updateHandshakeKeys(k, 125);
+		assertSame(k.getNextIncomingKeys(), k1.getPreviousIncomingKeys());
+	}
+
+	@Test
+	public void testKeysAreUpdatedByThreePeriods() {
+		HandshakeKeys k = transportCrypto.deriveHandshakeKeys(transportId,
+				rootKey, 123, true);
+		HandshakeKeys k1 = transportCrypto.updateHandshakeKeys(k, 126);
+		assertAllDifferent(k, k1);
+	}
+
+	@Test
+	public void testCurrentKeysMatchContact() {
+		// Start in time period 123
+		HandshakeKeys kA = transportCrypto.deriveHandshakeKeys(transportId,
+				rootKey, 123, true);
+		HandshakeKeys kB = transportCrypto.deriveHandshakeKeys(transportId,
+				rootKey, 123, false);
+		// Alice's incoming keys should equal Bob's outgoing keys
+		assertMatches(kA.getCurrentIncomingKeys(), kB.getCurrentOutgoingKeys());
+		// Bob's incoming keys should equal Alice's outgoing keys
+		assertMatches(kB.getCurrentIncomingKeys(), kA.getCurrentOutgoingKeys());
+		// Update into the future
+		kA = transportCrypto.updateHandshakeKeys(kA, 456);
+		kB = transportCrypto.updateHandshakeKeys(kB, 456);
+		// Alice's incoming keys should equal Bob's outgoing keys
+		assertMatches(kA.getCurrentIncomingKeys(), kB.getCurrentOutgoingKeys());
+		// Bob's incoming keys should equal Alice's outgoing keys
+		assertMatches(kB.getCurrentIncomingKeys(), kA.getCurrentOutgoingKeys());
+	}
+
+	@Test
+	public void testPreviousKeysMatchContact() {
+		// Start in time period 123
+		HandshakeKeys kA = transportCrypto.deriveHandshakeKeys(transportId,
+				rootKey, 123, true);
+		HandshakeKeys kB = transportCrypto.deriveHandshakeKeys(transportId,
+				rootKey, 123, false);
+		// Compare Alice's previous keys in period 456 with Bob's current keys
+		// in period 455
+		kA = transportCrypto.updateHandshakeKeys(kA, 456);
+		kB = transportCrypto.updateHandshakeKeys(kB, 455);
+		// Alice's previous incoming keys should equal Bob's current
+		// outgoing keys
+		assertMatches(kA.getPreviousIncomingKeys(),
+				kB.getCurrentOutgoingKeys());
+		// Compare Alice's current keys in period 456 with Bob's previous keys
+		// in period 457
+		kB = transportCrypto.updateHandshakeKeys(kB, 457);
+		// Bob's previous incoming keys should equal Alice's current
+		// outgoing keys
+		assertMatches(kB.getPreviousIncomingKeys(),
+				kA.getCurrentOutgoingKeys());
+	}
+
+	@Test
+	public void testNextKeysMatchContact() {
+		// Start in time period 123
+		HandshakeKeys kA = transportCrypto.deriveHandshakeKeys(transportId,
+				rootKey, 123, true);
+		HandshakeKeys kB = transportCrypto.deriveHandshakeKeys(transportId,
+				rootKey, 123, false);
+		// Compare Alice's current keys in period 456 with Bob's next keys in
+		// period 455
+		kA = transportCrypto.updateHandshakeKeys(kA, 456);
+		kB = transportCrypto.updateHandshakeKeys(kB, 455);
+		// Bob's next incoming keys should equal Alice's current outgoing keys
+		assertMatches(kB.getNextIncomingKeys(), kA.getCurrentOutgoingKeys());
+		// Compare Alice's next keys in period 456 with Bob's current keys
+		// in period 457
+		kB = transportCrypto.updateHandshakeKeys(kB, 457);
+		// Alice's next incoming keys should equal Bob's current outgoing keys
+		assertMatches(kA.getNextIncomingKeys(), kB.getCurrentOutgoingKeys());
+	}
+
+	@Test
+	public void testRootKeyAffectsOutput() {
+		SecretKey rootKey1 = getSecretKey();
+		assertFalse(Arrays.equals(rootKey.getBytes(), rootKey1.getBytes()));
+		HandshakeKeys k = transportCrypto.deriveHandshakeKeys(transportId,
+				rootKey, 123, true);
+		HandshakeKeys k1 = transportCrypto.deriveHandshakeKeys(transportId,
+				rootKey1, 123, true);
+		assertAllDifferent(k, k1);
+	}
+
+	@Test
+	public void testTransportIdAffectsOutput() {
+		TransportId transportId1 = getTransportId();
+		assertNotEquals(transportId.getString(), transportId1.getString());
+		HandshakeKeys k = transportCrypto.deriveHandshakeKeys(transportId,
+				rootKey, 123, true);
+		HandshakeKeys k1 = transportCrypto.deriveHandshakeKeys(transportId1,
+				rootKey, 123, true);
+		assertAllDifferent(k, k1);
+	}
+}

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

@@ -1,167 +0,0 @@
-package org.briarproject.bramble.crypto;
-
-import org.briarproject.bramble.api.Bytes;
-import org.briarproject.bramble.api.crypto.CryptoComponent;
-import org.briarproject.bramble.api.crypto.SecretKey;
-import org.briarproject.bramble.api.crypto.TransportCrypto;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.transport.TransportKeys;
-import org.briarproject.bramble.test.BrambleTestCase;
-import org.briarproject.bramble.test.TestSecureRandomProvider;
-import org.junit.Test;
-
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
-
-import static org.briarproject.bramble.test.TestUtils.getSecretKey;
-import static org.briarproject.bramble.test.TestUtils.getTransportId;
-import static org.junit.Assert.assertArrayEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-public class KeyDerivationTest extends BrambleTestCase {
-
-	private final CryptoComponent crypto =
-			new CryptoComponentImpl(new TestSecureRandomProvider(), null);
-	private final TransportCrypto transportCrypto =
-			new TransportCryptoImpl(crypto);
-	private final TransportId transportId = getTransportId();
-	private final SecretKey master = getSecretKey();
-
-	@Test
-	public void testKeysAreDistinct() {
-		TransportKeys k = transportCrypto.deriveTransportKeys(transportId,
-				master, 123, true, true);
-		assertAllDifferent(k);
-	}
-
-	@Test
-	public void testCurrentKeysMatchCurrentKeysOfContact() {
-		// Start in rotation period 123
-		TransportKeys kA = transportCrypto.deriveTransportKeys(transportId,
-				master, 123, true, true);
-		TransportKeys kB = transportCrypto.deriveTransportKeys(transportId,
-				master, 123, false, true);
-		// Alice's incoming keys should equal Bob's outgoing keys
-		assertArrayEquals(kA.getCurrentIncomingKeys().getTagKey().getBytes(),
-				kB.getCurrentOutgoingKeys().getTagKey().getBytes());
-		assertArrayEquals(kA.getCurrentIncomingKeys().getHeaderKey().getBytes(),
-				kB.getCurrentOutgoingKeys().getHeaderKey().getBytes());
-		// Alice's outgoing keys should equal Bob's incoming keys
-		assertArrayEquals(kA.getCurrentOutgoingKeys().getTagKey().getBytes(),
-				kB.getCurrentIncomingKeys().getTagKey().getBytes());
-		assertArrayEquals(kA.getCurrentOutgoingKeys().getHeaderKey().getBytes(),
-				kB.getCurrentIncomingKeys().getHeaderKey().getBytes());
-		// Rotate into the future
-		kA = transportCrypto.rotateTransportKeys(kA, 456);
-		kB = transportCrypto.rotateTransportKeys(kB, 456);
-		// Alice's incoming keys should equal Bob's outgoing keys
-		assertArrayEquals(kA.getCurrentIncomingKeys().getTagKey().getBytes(),
-				kB.getCurrentOutgoingKeys().getTagKey().getBytes());
-		assertArrayEquals(kA.getCurrentIncomingKeys().getHeaderKey().getBytes(),
-				kB.getCurrentOutgoingKeys().getHeaderKey().getBytes());
-		// Alice's outgoing keys should equal Bob's incoming keys
-		assertArrayEquals(kA.getCurrentOutgoingKeys().getTagKey().getBytes(),
-				kB.getCurrentIncomingKeys().getTagKey().getBytes());
-		assertArrayEquals(kA.getCurrentOutgoingKeys().getHeaderKey().getBytes(),
-				kB.getCurrentIncomingKeys().getHeaderKey().getBytes());
-	}
-
-	@Test
-	public void testPreviousKeysMatchPreviousKeysOfContact() {
-		// Start in rotation period 123
-		TransportKeys kA = transportCrypto.deriveTransportKeys(transportId,
-				master, 123, true, true);
-		TransportKeys kB = transportCrypto.deriveTransportKeys(transportId,
-				master, 123, false, true);
-		// Compare Alice's previous keys in period 456 with Bob's current keys
-		// in period 455
-		kA = transportCrypto.rotateTransportKeys(kA, 456);
-		kB = transportCrypto.rotateTransportKeys(kB, 455);
-		// Alice's previous incoming keys should equal Bob's outgoing keys
-		assertArrayEquals(kA.getPreviousIncomingKeys().getTagKey().getBytes(),
-				kB.getCurrentOutgoingKeys().getTagKey().getBytes());
-		assertArrayEquals(
-				kA.getPreviousIncomingKeys().getHeaderKey().getBytes(),
-				kB.getCurrentOutgoingKeys().getHeaderKey().getBytes());
-		// Compare Alice's current keys in period 456 with Bob's previous keys
-		// in period 457
-		kB = transportCrypto.rotateTransportKeys(kB, 457);
-		// Alice's outgoing keys should equal Bob's previous incoming keys
-		assertArrayEquals(kA.getCurrentOutgoingKeys().getTagKey().getBytes(),
-				kB.getPreviousIncomingKeys().getTagKey().getBytes());
-		assertArrayEquals(kA.getCurrentOutgoingKeys().getHeaderKey().getBytes(),
-				kB.getPreviousIncomingKeys().getHeaderKey().getBytes());
-	}
-
-	@Test
-	public void testNextKeysMatchNextKeysOfContact() {
-		// Start in rotation period 123
-		TransportKeys kA = transportCrypto.deriveTransportKeys(transportId,
-				master, 123, true, true);
-		TransportKeys kB = transportCrypto.deriveTransportKeys(transportId,
-				master, 123, false, true);
-		// Compare Alice's current keys in period 456 with Bob's next keys in
-		// period 455
-		kA = transportCrypto.rotateTransportKeys(kA, 456);
-		kB = transportCrypto.rotateTransportKeys(kB, 455);
-		// Alice's outgoing keys should equal Bob's next incoming keys
-		assertArrayEquals(kA.getCurrentOutgoingKeys().getTagKey().getBytes(),
-				kB.getNextIncomingKeys().getTagKey().getBytes());
-		assertArrayEquals(kA.getCurrentOutgoingKeys().getHeaderKey().getBytes(),
-				kB.getNextIncomingKeys().getHeaderKey().getBytes());
-		// Compare Alice's next keys in period 456 with Bob's current keys
-		// in period 457
-		kB = transportCrypto.rotateTransportKeys(kB, 457);
-		// Alice's next incoming keys should equal Bob's outgoing keys
-		assertArrayEquals(kA.getNextIncomingKeys().getTagKey().getBytes(),
-				kB.getCurrentOutgoingKeys().getTagKey().getBytes());
-		assertArrayEquals(kA.getNextIncomingKeys().getHeaderKey().getBytes(),
-				kB.getCurrentOutgoingKeys().getHeaderKey().getBytes());
-	}
-
-	@Test
-	public void testMasterKeyAffectsOutput() {
-		SecretKey master1 = getSecretKey();
-		assertFalse(Arrays.equals(master.getBytes(), master1.getBytes()));
-		TransportKeys k = transportCrypto.deriveTransportKeys(transportId,
-				master, 123, true, true);
-		TransportKeys k1 = transportCrypto.deriveTransportKeys(transportId,
-				master1, 123, true, true);
-		assertAllDifferent(k, k1);
-	}
-
-	@Test
-	public void testTransportIdAffectsOutput() {
-		TransportId transportId1 = getTransportId();
-		assertFalse(transportId.getString().equals(transportId1.getString()));
-		TransportKeys k = transportCrypto.deriveTransportKeys(transportId,
-				master, 123, true, true);
-		TransportKeys k1 = transportCrypto.deriveTransportKeys(transportId1,
-				master, 123, true, true);
-		assertAllDifferent(k, k1);
-	}
-
-	private void assertAllDifferent(TransportKeys... transportKeys) {
-		List<SecretKey> secretKeys = new ArrayList<>();
-		for (TransportKeys k : transportKeys) {
-			secretKeys.add(k.getPreviousIncomingKeys().getTagKey());
-			secretKeys.add(k.getPreviousIncomingKeys().getHeaderKey());
-			secretKeys.add(k.getCurrentIncomingKeys().getTagKey());
-			secretKeys.add(k.getCurrentIncomingKeys().getHeaderKey());
-			secretKeys.add(k.getNextIncomingKeys().getTagKey());
-			secretKeys.add(k.getNextIncomingKeys().getHeaderKey());
-			secretKeys.add(k.getCurrentOutgoingKeys().getTagKey());
-			secretKeys.add(k.getCurrentOutgoingKeys().getHeaderKey());
-		}
-		assertAllDifferent(secretKeys);
-	}
-
-	private void assertAllDifferent(List<SecretKey> keys) {
-		Set<Bytes> set = new HashSet<>();
-		for (SecretKey k : keys) assertTrue(set.add(new Bytes(k.getBytes())));
-	}
-}

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

@@ -0,0 +1,45 @@
+package org.briarproject.bramble.crypto;
+
+import org.briarproject.bramble.api.Bytes;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.transport.AbstractTransportKeys;
+import org.briarproject.bramble.api.transport.IncomingKeys;
+import org.briarproject.bramble.api.transport.OutgoingKeys;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertTrue;
+
+class KeyDerivationTestUtils {
+
+	static void assertAllDifferent(AbstractTransportKeys... transportKeys) {
+		List<SecretKey> secretKeys = new ArrayList<>();
+		for (AbstractTransportKeys k : transportKeys) {
+			secretKeys.add(k.getPreviousIncomingKeys().getTagKey());
+			secretKeys.add(k.getPreviousIncomingKeys().getHeaderKey());
+			secretKeys.add(k.getCurrentIncomingKeys().getTagKey());
+			secretKeys.add(k.getCurrentIncomingKeys().getHeaderKey());
+			secretKeys.add(k.getNextIncomingKeys().getTagKey());
+			secretKeys.add(k.getNextIncomingKeys().getHeaderKey());
+			secretKeys.add(k.getCurrentOutgoingKeys().getTagKey());
+			secretKeys.add(k.getCurrentOutgoingKeys().getHeaderKey());
+		}
+		assertAllDifferent(secretKeys);
+	}
+
+	static void assertAllDifferent(List<SecretKey> keys) {
+		Set<Bytes> set = new HashSet<>();
+		for (SecretKey k : keys) assertTrue(set.add(new Bytes(k.getBytes())));
+	}
+
+	static void assertMatches(IncomingKeys in, OutgoingKeys out) {
+		assertArrayEquals(in.getTagKey().getBytes(),
+				out.getTagKey().getBytes());
+		assertArrayEquals(in.getHeaderKey().getBytes(),
+				out.getHeaderKey().getBytes());
+	}
+}

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

@@ -0,0 +1,167 @@
+package org.briarproject.bramble.crypto;
+
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.crypto.TransportCrypto;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.transport.TransportKeys;
+import org.briarproject.bramble.test.BrambleTestCase;
+import org.briarproject.bramble.test.TestSecureRandomProvider;
+import org.junit.Test;
+
+import java.util.Arrays;
+
+import static org.briarproject.bramble.crypto.KeyDerivationTestUtils.assertAllDifferent;
+import static org.briarproject.bramble.crypto.KeyDerivationTestUtils.assertMatches;
+import static org.briarproject.bramble.test.TestUtils.getSecretKey;
+import static org.briarproject.bramble.test.TestUtils.getTransportId;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertSame;
+
+public class TransportKeyDerivationTest extends BrambleTestCase {
+
+	private final CryptoComponent crypto =
+			new CryptoComponentImpl(new TestSecureRandomProvider(), null);
+	private final TransportCrypto transportCrypto =
+			new TransportCryptoImpl(crypto);
+	private final TransportId transportId = getTransportId();
+	private final SecretKey rootKey = getSecretKey();
+
+	@Test
+	public void testKeysAreDistinct() {
+		TransportKeys kA = transportCrypto.deriveTransportKeys(transportId,
+				rootKey, 123, true, true);
+		TransportKeys kB = transportCrypto.deriveTransportKeys(transportId,
+				rootKey, 123, false, true);
+		assertAllDifferent(kA);
+		assertAllDifferent(kB);
+	}
+
+	@Test
+	public void testKeysAreNotRotatedToPreviousPeriod() {
+		TransportKeys k = transportCrypto.deriveTransportKeys(transportId,
+				rootKey, 123, true, true);
+		TransportKeys k1 = transportCrypto.rotateTransportKeys(k, 122);
+		assertSame(k, k1);
+	}
+
+	@Test
+	public void testKeysAreNotRotatedToCurrentPeriod() {
+		TransportKeys k = transportCrypto.deriveTransportKeys(transportId,
+				rootKey, 123, true, true);
+		TransportKeys k1 = transportCrypto.rotateTransportKeys(k, 123);
+		assertSame(k, k1);
+	}
+
+	@Test
+	public void testKeysAreRotatedByOnePeriod() {
+		TransportKeys k = transportCrypto.deriveTransportKeys(transportId,
+				rootKey, 123, true, true);
+		TransportKeys k1 = transportCrypto.rotateTransportKeys(k, 124);
+		assertSame(k.getCurrentIncomingKeys(), k1.getPreviousIncomingKeys());
+		assertSame(k.getNextIncomingKeys(), k1.getCurrentIncomingKeys());
+	}
+
+	@Test
+	public void testKeysAreRotatedByTwoPeriods() {
+		TransportKeys k = transportCrypto.deriveTransportKeys(transportId,
+				rootKey, 123, true, true);
+		TransportKeys k1 = transportCrypto.rotateTransportKeys(k, 125);
+		assertSame(k.getNextIncomingKeys(), k1.getPreviousIncomingKeys());
+	}
+
+	@Test
+	public void testKeysAreRotatedByThreePeriods() {
+		TransportKeys k = transportCrypto.deriveTransportKeys(transportId,
+				rootKey, 123, true, true);
+		TransportKeys k1 = transportCrypto.rotateTransportKeys(k, 126);
+		assertAllDifferent(k, k1);
+	}
+
+	@Test
+	public void testCurrentKeysMatchContact() {
+		// Start in time period 123
+		TransportKeys kA = transportCrypto.deriveTransportKeys(transportId,
+				rootKey, 123, true, true);
+		TransportKeys kB = transportCrypto.deriveTransportKeys(transportId,
+				rootKey, 123, false, true);
+		// Alice's incoming keys should equal Bob's outgoing keys
+		assertMatches(kA.getCurrentIncomingKeys(), kB.getCurrentOutgoingKeys());
+		// Bob's incoming keys should equal Alice's outgoing keys
+		assertMatches(kB.getCurrentIncomingKeys(), kA.getCurrentOutgoingKeys());
+		// Rotate into the future
+		kA = transportCrypto.rotateTransportKeys(kA, 456);
+		kB = transportCrypto.rotateTransportKeys(kB, 456);
+		// Alice's incoming keys should equal Bob's outgoing keys
+		assertMatches(kA.getCurrentIncomingKeys(), kB.getCurrentOutgoingKeys());
+		// Bob's incoming keys should equal Alice's outgoing keys
+		assertMatches(kB.getCurrentIncomingKeys(), kA.getCurrentOutgoingKeys());
+	}
+
+	@Test
+	public void testPreviousKeysMatchContact() {
+		// Start in time period 123
+		TransportKeys kA = transportCrypto.deriveTransportKeys(transportId,
+				rootKey, 123, true, true);
+		TransportKeys kB = transportCrypto.deriveTransportKeys(transportId,
+				rootKey, 123, false, true);
+		// Compare Alice's previous keys in period 456 with Bob's current keys
+		// in period 455
+		kA = transportCrypto.rotateTransportKeys(kA, 456);
+		kB = transportCrypto.rotateTransportKeys(kB, 455);
+		// Alice's previous incoming keys should equal Bob's current
+		// outgoing keys
+		assertMatches(kA.getPreviousIncomingKeys(),
+				kB.getCurrentOutgoingKeys());
+		// Compare Alice's current keys in period 456 with Bob's previous keys
+		// in period 457
+		kB = transportCrypto.rotateTransportKeys(kB, 457);
+		// Bob's previous incoming keys should equal Alice's current
+		// outgoing keys
+		assertMatches(kB.getPreviousIncomingKeys(),
+				kA.getCurrentOutgoingKeys());
+	}
+
+	@Test
+	public void testNextKeysMatchContact() {
+		// Start in time period 123
+		TransportKeys kA = transportCrypto.deriveTransportKeys(transportId,
+				rootKey, 123, true, true);
+		TransportKeys kB = transportCrypto.deriveTransportKeys(transportId,
+				rootKey, 123, false, true);
+		// Compare Alice's current keys in period 456 with Bob's next keys in
+		// period 455
+		kA = transportCrypto.rotateTransportKeys(kA, 456);
+		kB = transportCrypto.rotateTransportKeys(kB, 455);
+		// Bob's next incoming keys should equal Alice's current outgoing keys
+		assertMatches(kB.getNextIncomingKeys(), kA.getCurrentOutgoingKeys());
+		// Compare Alice's next keys in period 456 with Bob's current keys
+		// in period 457
+		kB = transportCrypto.rotateTransportKeys(kB, 457);
+		// Alice's next incoming keys should equal Bob's current outgoing keys
+		assertMatches(kA.getNextIncomingKeys(), kB.getCurrentOutgoingKeys());
+	}
+
+	@Test
+	public void testRootKeyAffectsOutput() {
+		SecretKey rootKey1 = getSecretKey();
+		assertFalse(Arrays.equals(rootKey.getBytes(), rootKey1.getBytes()));
+		TransportKeys k = transportCrypto.deriveTransportKeys(transportId,
+				rootKey, 123, true, true);
+		TransportKeys k1 = transportCrypto.deriveTransportKeys(transportId,
+				rootKey1, 123, true, true);
+		assertAllDifferent(k, k1);
+	}
+
+	@Test
+	public void testTransportIdAffectsOutput() {
+		TransportId transportId1 = getTransportId();
+		assertNotEquals(transportId.getString(), transportId1.getString());
+		TransportKeys k = transportCrypto.deriveTransportKeys(transportId,
+				rootKey, 123, true, true);
+		TransportKeys k1 = transportCrypto.deriveTransportKeys(transportId1,
+				rootKey, 123, true, true);
+		assertAllDifferent(k, k1);
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/db/DatabaseComponentImplTest.java

@@ -2,9 +2,9 @@ package org.briarproject.bramble.db;
 
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.PendingContactId;
 import org.briarproject.bramble.api.contact.event.ContactAddedEvent;
 import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
-import org.briarproject.bramble.api.contact.event.ContactStatusChangedEvent;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.ContactExistsException;
 import org.briarproject.bramble.api.db.DatabaseComponent;
@@ -13,7 +13,9 @@ import org.briarproject.bramble.api.db.NoSuchContactException;
 import org.briarproject.bramble.api.db.NoSuchGroupException;
 import org.briarproject.bramble.api.db.NoSuchLocalAuthorException;
 import org.briarproject.bramble.api.db.NoSuchMessageException;
+import org.briarproject.bramble.api.db.NoSuchPendingContactException;
 import org.briarproject.bramble.api.db.NoSuchTransportException;
+import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.LocalAuthor;
@@ -43,18 +45,21 @@ import org.briarproject.bramble.api.sync.event.MessageToAckEvent;
 import org.briarproject.bramble.api.sync.event.MessageToRequestEvent;
 import org.briarproject.bramble.api.sync.event.MessagesAckedEvent;
 import org.briarproject.bramble.api.sync.event.MessagesSentEvent;
+import org.briarproject.bramble.api.transport.HandshakeKeys;
 import org.briarproject.bramble.api.transport.IncomingKeys;
-import org.briarproject.bramble.api.transport.KeySet;
-import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.OutgoingKeys;
+import org.briarproject.bramble.api.transport.TransportKeySet;
+import org.briarproject.bramble.api.transport.TransportKeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
 import org.briarproject.bramble.test.BrambleMockTestCase;
 import org.briarproject.bramble.test.CaptureArgumentAction;
 import org.jmock.Expectations;
+import org.jmock.Sequence;
 import org.junit.Test;
 
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicReference;
 
 import static java.util.Arrays.asList;
@@ -70,13 +75,13 @@ import static org.briarproject.bramble.api.transport.TransportConstants.REORDERI
 import static org.briarproject.bramble.db.DatabaseConstants.MAX_OFFERED_MESSAGES;
 import static org.briarproject.bramble.test.TestUtils.getAuthor;
 import static org.briarproject.bramble.test.TestUtils.getClientId;
+import static org.briarproject.bramble.test.TestUtils.getContact;
 import static org.briarproject.bramble.test.TestUtils.getGroup;
 import static org.briarproject.bramble.test.TestUtils.getLocalAuthor;
 import static org.briarproject.bramble.test.TestUtils.getMessage;
 import static org.briarproject.bramble.test.TestUtils.getRandomId;
 import static org.briarproject.bramble.test.TestUtils.getSecretKey;
 import static org.briarproject.bramble.test.TestUtils.getTransportId;
-import static org.briarproject.bramble.util.StringUtils.getRandomString;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
@@ -87,9 +92,10 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 
 	@SuppressWarnings("unchecked")
 	private final Database<Object> database = context.mock(Database.class);
-	private final ShutdownManager shutdown =
+	private final ShutdownManager shutdownManager =
 			context.mock(ShutdownManager.class);
 	private final EventBus eventBus = context.mock(EventBus.class);
+	private final Executor eventExecutor = context.mock(Executor.class);
 
 	private final SecretKey key = getSecretKey();
 	private final Object txn = new Object();
@@ -107,7 +113,8 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 	private final int maxLatency;
 	private final ContactId contactId;
 	private final Contact contact;
-	private final KeySetId keySetId;
+	private final TransportKeySetId keySetId;
+	private final PendingContactId pendingContactId;
 
 	public DatabaseComponentImplTest() {
 		clientId = getClientId();
@@ -116,7 +123,6 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		groupId = group.getId();
 		author = getAuthor();
 		localAuthor = getLocalAuthor();
-		alias = getRandomString(5);
 		message = getMessage(groupId);
 		message1 = getMessage(groupId);
 		messageId = message.getId();
@@ -125,16 +131,18 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		metadata.put("foo", new byte[] {'b', 'a', 'r'});
 		transportId = getTransportId();
 		maxLatency = Integer.MAX_VALUE;
-		contactId = new ContactId(234);
-		contact = new Contact(contactId, author, localAuthor.getId(), alias,
-				true, true);
-		keySetId = new KeySetId(345);
+		contact = getContact(author, true);
+		contactId = contact.getId();
+		alias = contact.getAlias();
+		keySetId = new TransportKeySetId(345);
+		pendingContactId = new PendingContactId(getRandomId());
 	}
 
 	private DatabaseComponent createDatabaseComponent(Database<Object> database,
-			EventBus eventBus, ShutdownManager shutdown) {
+			EventBus eventBus, Executor eventExecutor,
+			ShutdownManager shutdownManager) {
 		return new DatabaseComponentImpl<>(database, Object.class, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 	}
 
 	@Test
@@ -144,7 +152,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			// open()
 			oneOf(database).open(key, null);
 			will(returnValue(false));
-			oneOf(shutdown).addShutdownHook(with(any(Runnable.class)));
+			oneOf(shutdownManager).addShutdownHook(with(any(Runnable.class)));
 			will(returnValue(shutdownHandle));
 			// startTransaction()
 			oneOf(database).startTransaction();
@@ -155,19 +163,13 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).addLocalAuthor(txn, localAuthor);
 			oneOf(eventBus).broadcast(with(any(LocalAuthorAddedEvent.class)));
 			// addContact()
-			oneOf(database).containsLocalAuthor(txn, localAuthor.getId());
-			will(returnValue(true));
 			oneOf(database).containsLocalAuthor(txn, author.getId());
 			will(returnValue(false));
-			oneOf(database).containsContact(txn, author.getId(),
-					localAuthor.getId());
+			oneOf(database).containsContact(txn, author.getId());
 			will(returnValue(false));
-			oneOf(database).addContact(txn, author, localAuthor.getId(),
-					true, true);
+			oneOf(database).addContact(txn, author, true);
 			will(returnValue(contactId));
 			oneOf(eventBus).broadcast(with(any(ContactAddedEvent.class)));
-			oneOf(eventBus).broadcast(with(any(
-					ContactStatusChangedEvent.class)));
 			// getContacts()
 			oneOf(database).getContacts(txn);
 			will(returnValue(singletonList(contact)));
@@ -207,13 +209,12 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).close();
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		assertFalse(db.open(key, null));
 		db.transaction(false, transaction -> {
 			db.addLocalAuthor(transaction, localAuthor);
-			assertEquals(contactId, db.addContact(transaction, author,
-					localAuthor.getId(), true, true));
+			assertEquals(contactId, db.addContact(transaction, author, true));
 			assertEquals(singletonList(contact),
 					db.getContacts(transaction));
 			db.addGroup(transaction, group); // First time - listeners called
@@ -238,7 +239,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).abortTransaction(txn);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(false, transaction ->
 				db.addLocalMessage(transaction, message, metadata, true));
@@ -263,7 +264,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(any(MessageSharedEvent.class)));
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(false, transaction ->
 				db.addLocalMessage(transaction, message, metadata, true));
@@ -274,14 +275,25 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			throws Exception {
 		context.checking(new Expectations() {{
 			// Check whether the contact is in the DB (which it's not)
-			exactly(17).of(database).startTransaction();
+			exactly(18).of(database).startTransaction();
 			will(returnValue(txn));
 			exactly(17).of(database).containsContact(txn, contactId);
 			will(returnValue(false));
-			exactly(17).of(database).abortTransaction(txn);
+			oneOf(database).containsContact(txn, author.getId());
+			will(returnValue(false));
+			exactly(18).of(database).abortTransaction(txn);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
+
+		try {
+			db.transaction(false, transaction ->
+					db.addHandshakeKeys(transaction, contactId,
+							createHandshakeKeys()));
+			fail();
+		} catch (NoSuchContactException expected) {
+			// Expected
+		}
 
 		try {
 			db.transaction(false, transaction ->
@@ -332,6 +344,14 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			// Expected
 		}
 
+		try {
+			db.transaction(false, transaction ->
+					db.getContact(transaction, author.getId()));
+			fail();
+		} catch (NoSuchContactException expected) {
+			// Expected
+		}
+
 		try {
 			db.transaction(false, transaction ->
 					db.getMessageStatus(transaction, contactId, groupId));
@@ -399,14 +419,6 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			// Expected
 		}
 
-		try {
-			db.transaction(false, transaction ->
-					db.setContactActive(transaction, contactId, true));
-			fail();
-		} catch (NoSuchContactException expected) {
-			// Expected
-		}
-
 		try {
 			db.transaction(false, transaction ->
 					db.setContactAlias(transaction, contactId, alias));
@@ -430,24 +442,15 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			throws Exception {
 		context.checking(new Expectations() {{
 			// Check whether the pseudonym is in the DB (which it's not)
-			exactly(3).of(database).startTransaction();
+			exactly(2).of(database).startTransaction();
 			will(returnValue(txn));
-			exactly(3).of(database).containsLocalAuthor(txn,
+			exactly(2).of(database).containsLocalAuthor(txn,
 					localAuthor.getId());
 			will(returnValue(false));
-			exactly(3).of(database).abortTransaction(txn);
+			exactly(2).of(database).abortTransaction(txn);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
-
-		try {
-			db.transaction(false, transaction ->
-					db.addContact(transaction, author, localAuthor.getId(),
-							true, true));
-			fail();
-		} catch (NoSuchLocalAuthorException expected) {
-			// Expected
-		}
+				eventExecutor, shutdownManager);
 
 		try {
 			db.transaction(false, transaction ->
@@ -481,7 +484,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			will(returnValue(true));
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		try {
 			db.transaction(false, transaction ->
@@ -565,7 +568,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			will(returnValue(true));
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		try {
 			db.transaction(false, transaction ->
@@ -668,7 +671,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			exactly(5).of(database).abortTransaction(txn);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		try {
 			db.transaction(false, transaction ->
@@ -713,6 +716,39 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}
 	}
 
+	@Test
+	public void testVariousMethodsThrowExceptionIfPendingContactIsMissing()
+			throws Exception {
+		context.checking(new Expectations() {{
+			// Check whether the pending contact is in the DB (which it's not)
+			exactly(2).of(database).startTransaction();
+			will(returnValue(txn));
+			exactly(2).of(database).containsPendingContact(txn,
+					pendingContactId);
+			will(returnValue(false));
+			exactly(2).of(database).abortTransaction(txn);
+		}});
+		DatabaseComponent db = createDatabaseComponent(database, eventBus,
+				eventExecutor, shutdownManager);
+
+		try {
+			db.transaction(false, transaction ->
+					db.addHandshakeKeys(transaction, pendingContactId,
+							createHandshakeKeys()));
+			fail();
+		} catch (NoSuchPendingContactException expected) {
+			// Expected
+		}
+
+		try {
+			db.transaction(false, transaction ->
+					db.removePendingContact(transaction, pendingContactId));
+			fail();
+		} catch (NoSuchPendingContactException expected) {
+			// Expected
+		}
+	}
+
 	@Test
 	public void testGenerateAck() throws Exception {
 		Collection<MessageId> messagesToAck = asList(messageId, messageId1);
@@ -727,7 +763,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).commitTransaction(txn);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(false, transaction -> {
 			Ack a = db.generateAck(transaction, contactId, 123);
@@ -761,7 +797,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(any(MessagesSentEvent.class)));
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(false, transaction ->
 				assertEquals(messages, db.generateBatch(transaction, contactId,
@@ -786,7 +822,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).commitTransaction(txn);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(false, transaction -> {
 			Offer o = db.generateOffer(transaction, contactId, 123, maxLatency);
@@ -810,7 +846,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).commitTransaction(txn);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(false, transaction -> {
 			Request r = db.generateRequest(transaction, contactId, 123);
@@ -844,7 +880,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(any(MessagesSentEvent.class)));
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(false, transaction ->
 				assertEquals(messages, db.generateRequestedBatch(transaction,
@@ -865,7 +901,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(any(MessagesAckedEvent.class)));
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(false, transaction -> {
 			Ack a = new Ack(singletonList(messageId));
@@ -903,7 +939,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(any(MessageToAckEvent.class)));
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(false, transaction -> {
 			// Receive the message twice
@@ -931,7 +967,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(any(MessageToAckEvent.class)));
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(false, transaction ->
 				db.receiveMessage(transaction, contactId, message));
@@ -949,7 +985,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).commitTransaction(txn);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(false, transaction ->
 				db.receiveMessage(transaction, contactId, message));
@@ -989,7 +1025,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(any(MessageToRequestEvent.class)));
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		Offer o = new Offer(asList(messageId, messageId1,
 				messageId2, messageId3));
@@ -1012,7 +1048,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(any(MessageRequestedEvent.class)));
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		Request r = new Request(singletonList(messageId));
 		db.transaction(false, transaction ->
@@ -1042,7 +1078,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 					GroupVisibilityUpdatedEvent.class, 0));
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(false, transaction ->
 				db.setGroupVisibility(transaction, contactId, groupId,
@@ -1076,7 +1112,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 					GroupVisibilityUpdatedEvent.class, 0));
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(false, transaction ->
 				db.setGroupVisibility(transaction, contactId, groupId,
@@ -1102,7 +1138,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).commitTransaction(txn);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(false, transaction ->
 				db.setGroupVisibility(transaction, contactId, groupId,
@@ -1112,8 +1148,9 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 	@Test
 	public void testTransportKeys() throws Exception {
 		TransportKeys transportKeys = createTransportKeys();
-		KeySet ks = new KeySet(keySetId, contactId, transportKeys);
-		Collection<KeySet> keys = singletonList(ks);
+		TransportKeySet ks =
+				new TransportKeySet(keySetId, contactId, transportKeys);
+		Collection<TransportKeySet> keys = singletonList(ks);
 
 		context.checking(new Expectations() {{
 			// startTransaction()
@@ -1132,7 +1169,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).commitTransaction(txn);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(false, transaction -> {
 			db.updateTransportKeys(transaction, keys);
@@ -1171,7 +1208,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).commitTransaction(txn);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(true, transaction -> {
 			// With visible group - return stored status
@@ -1221,7 +1258,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).commitTransaction(txn);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(true, transaction -> {
 			// With visible group - return stored status
@@ -1240,6 +1277,27 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		});
 	}
 
+	private HandshakeKeys createHandshakeKeys() {
+		SecretKey inPrevTagKey = getSecretKey();
+		SecretKey inPrevHeaderKey = getSecretKey();
+		IncomingKeys inPrev = new IncomingKeys(inPrevTagKey, inPrevHeaderKey,
+				1, 123, new byte[4]);
+		SecretKey inCurrTagKey = getSecretKey();
+		SecretKey inCurrHeaderKey = getSecretKey();
+		IncomingKeys inCurr = new IncomingKeys(inCurrTagKey, inCurrHeaderKey,
+				2, 234, new byte[4]);
+		SecretKey inNextTagKey = getSecretKey();
+		SecretKey inNextHeaderKey = getSecretKey();
+		IncomingKeys inNext = new IncomingKeys(inNextTagKey, inNextHeaderKey,
+				3, 345, new byte[4]);
+		SecretKey outCurrTagKey = getSecretKey();
+		SecretKey outCurrHeaderKey = getSecretKey();
+		OutgoingKeys outCurr = new OutgoingKeys(outCurrTagKey, outCurrHeaderKey,
+				2, 456, true);
+		return new HandshakeKeys(transportId, inPrev, inCurr, inNext, outCurr,
+				getSecretKey(), true);
+	}
+
 	private TransportKeys createTransportKeys() {
 		SecretKey inPrevTagKey = getSecretKey();
 		SecretKey inPrevHeaderKey = getSecretKey();
@@ -1287,7 +1345,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}});
 
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		db.transaction(false, transaction -> {
 			// First merge should broadcast an event
@@ -1330,7 +1388,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}});
 
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		assertNotNull(db.startTransaction(firstTxnReadOnly));
 		db.startTransaction(secondTxnReadOnly);
@@ -1342,8 +1400,6 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
-			oneOf(database).containsLocalAuthor(txn, localAuthor.getId());
-			will(returnValue(true));
 			// Contact is a local identity
 			oneOf(database).containsLocalAuthor(txn, author.getId());
 			will(returnValue(true));
@@ -1351,12 +1407,11 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}});
 
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		try {
 			db.transaction(false, transaction ->
-					db.addContact(transaction, author, localAuthor.getId(),
-							true, true));
+					db.addContact(transaction, author, true));
 			fail();
 		} catch (ContactExistsException expected) {
 			// Expected
@@ -1368,24 +1423,20 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
-			oneOf(database).containsLocalAuthor(txn, localAuthor.getId());
-			will(returnValue(true));
 			oneOf(database).containsLocalAuthor(txn, author.getId());
 			will(returnValue(false));
-			// Contact already exists for this local identity
-			oneOf(database).containsContact(txn, author.getId(),
-					localAuthor.getId());
+			// Contact already exists
+			oneOf(database).containsContact(txn, author.getId());
 			will(returnValue(true));
 			oneOf(database).abortTransaction(txn);
 		}});
 
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		try {
 			db.transaction(false, transaction ->
-					db.addContact(transaction, author, localAuthor.getId(),
-							true, true));
+					db.addContact(transaction, author, true));
 			fail();
 		} catch (ContactExistsException expected) {
 			// Expected
@@ -1401,7 +1452,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			// open()
 			oneOf(database).open(key, null);
 			will(returnValue(false));
-			oneOf(shutdown).addShutdownHook(with(any(Runnable.class)));
+			oneOf(shutdownManager).addShutdownHook(with(any(Runnable.class)));
 			will(returnValue(shutdownHandle));
 			// startTransaction()
 			oneOf(database).startTransaction();
@@ -1441,7 +1492,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).close();
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
-				shutdown);
+				eventExecutor, shutdownManager);
 
 		assertFalse(db.open(key, null));
 		db.transaction(false, transaction -> {
@@ -1455,4 +1506,43 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		});
 		db.close();
 	}
+
+	@Test
+	public void testCommitActionsOccurInOrder() throws Exception {
+		TestEvent action1 = new TestEvent();
+		Runnable action2 = () -> {
+		};
+		TestEvent action3 = new TestEvent();
+		Runnable action4 = () -> {
+		};
+
+		Sequence sequence = context.sequence("sequence");
+		context.checking(new Expectations() {{
+			oneOf(database).startTransaction();
+			will(returnValue(txn));
+			inSequence(sequence);
+			oneOf(database).commitTransaction(txn);
+			inSequence(sequence);
+			oneOf(eventBus).broadcast(action1);
+			inSequence(sequence);
+			oneOf(eventExecutor).execute(action2);
+			inSequence(sequence);
+			oneOf(eventBus).broadcast(action3);
+			inSequence(sequence);
+			oneOf(eventExecutor).execute(action4);
+			inSequence(sequence);
+		}});
+		DatabaseComponent db = createDatabaseComponent(database, eventBus,
+				eventExecutor, shutdownManager);
+
+		db.transaction(false, transaction -> {
+			transaction.attach(action1);
+			transaction.attach(action2);
+			transaction.attach(action3);
+			transaction.attach(action4);
+		});
+	}
+
+	private static class TestEvent extends Event {
+	}
 }

bramble-core/src/test/java/org/briarproject/bramble/db/DatabaseMigrationTest.java

@@ -45,8 +45,7 @@ public abstract class DatabaseMigrationTest extends BrambleMockTestCase {
 	private final Migration<Connection> migration1 =
 			context.mock(Migration.class, "migration1");
 
-	protected final DatabaseConfig config =
-			new TestDatabaseConfig(testDir, 1024 * 1024);
+	protected final DatabaseConfig config = new TestDatabaseConfig(testDir);
 	protected final MessageFactory messageFactory = new TestMessageFactory();
 	protected final SecretKey key = getSecretKey();
 	protected final Clock clock = new SystemClock();