Add executor with high and low priority queues.

.idea/codeStyles/Project.xml

@@ -39,6 +39,31 @@
     <JetCodeStyleSettings>
       <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
     </JetCodeStyleSettings>
+    <Objective-C-extensions>
+      <file>
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Import" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Macro" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Typedef" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Enum" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Constant" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Global" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Struct" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="FunctionPredecl" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Function" />
+      </file>
+      <class>
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Property" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Synthesize" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="InitMethod" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="StaticMethod" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="InstanceMethod" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="DeallocMethod" />
+      </class>
+      <extensions>
+        <pair source="cpp" header="h" fileNamingConvention="NONE" />
+        <pair source="c" header="h" fileNamingConvention="NONE" />
+      </extensions>
+    </Objective-C-extensions>
     <XML>
       <option name="XML_LEGACY_SETTINGS_IMPORTED" value="true" />
     </XML>

bramble-android/build.gradle

@@ -11,8 +11,8 @@ android {
 	defaultConfig {
 		minSdkVersion 14
 		targetSdkVersion 26
-		versionCode 10107
+		versionCode 10105
-		versionName "1.1.7"
+		versionName "1.1.5"
 		consumerProguardFiles 'proguard-rules.txt'
 
 		testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
@@ -30,10 +30,10 @@ configurations {
 
 dependencies {
 	implementation project(path: ':bramble-core', configuration: 'default')
-	tor 'org.briarproject:tor-android:0.3.5.8@zip'
+	tor 'org.briarproject:tor-android:0.3.4.8@zip'
-	tor 'org.briarproject:obfs4proxy-android:0.0.9@zip'
+	tor 'org.briarproject:obfs4proxy-android:0.0.7@zip'
 
-	annotationProcessor 'com.google.dagger:dagger-compiler:2.22.1'
+	annotationProcessor 'com.google.dagger:dagger-compiler:2.19'
 
 	compileOnly 'javax.annotation:jsr250-api:1.0'
 

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

@@ -9,20 +9,14 @@ import org.briarproject.bramble.api.account.AccountManager;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.db.DatabaseConfig;
 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;
-import static java.util.logging.Level.INFO;
-import static org.briarproject.bramble.util.IoUtils.deleteFileOrDir;
-import static org.briarproject.bramble.util.LogUtils.logFileOrDir;
-
 class AndroidAccountManager extends AccountManagerImpl
 		implements AccountManager {
 
@@ -43,16 +37,6 @@ class AndroidAccountManager extends AccountManagerImpl
 		appContext = app.getApplicationContext();
 	}
 
-	@Override
-	public boolean accountExists() {
-		boolean exists = super.accountExists();
-		if (!exists && LOG.isLoggable(INFO)) {
-			LOG.info("Account does not exist. Contents of account directory:");
-			logFileOrDir(LOG, INFO, getDataDir());
-		}
-		return exists;
-	}
-
 	// Locking: stateChangeLock
 	@Override
 	@Nullable
@@ -86,17 +70,9 @@ class AndroidAccountManager extends AccountManagerImpl
 	@Override
 	public void deleteAccount() {
 		synchronized (stateChangeLock) {
-			if (LOG.isLoggable(INFO)) {
-				LOG.info("Contents of account directory before deleting:");
-				logFileOrDir(LOG, INFO, getDataDir());
-			}
 			super.deleteAccount();
 			SharedPreferences defaultPrefs = getDefaultSharedPreferences();
 			deleteAppData(prefs, defaultPrefs);
-			if (LOG.isLoggable(INFO)) {
-				LOG.info("Contents of account directory after deleting:");
-				logFileOrDir(LOG, INFO, getDataDir());
-			}
 		}
 	}
 
@@ -113,46 +89,20 @@ class AndroidAccountManager extends AccountManagerImpl
 				LOG.warning("Could not clear shared preferences");
 		}
 		// Delete files, except lib and shared_prefs directories
-		Set<File> files = new HashSet<>();
+		File dataDir = new File(appContext.getApplicationInfo().dataDir);
-		File dataDir = getDataDir();
+		File[] children = dataDir.listFiles();
-		@Nullable
+		if (children == null) {
-		File[] fileArray = dataDir.listFiles();
-		if (fileArray == null) {
 			LOG.warning("Could not list files in app data dir");
 		} else {
-			for (File file : fileArray) {
+			for (File child : children) {
-				String name = file.getName();
+				String name = child.getName();
 				if (!name.equals("lib") && !name.equals("shared_prefs")) {
-					files.add(file);
+					IoUtils.deleteFileOrDir(child);
 				}
 			}
 		}
-		files.add(appContext.getFilesDir());
-		files.add(appContext.getCacheDir());
-		addIfNotNull(files, appContext.getExternalCacheDir());
-		if (SDK_INT >= 19) {
-			for (File file : appContext.getExternalCacheDirs()) {
-				addIfNotNull(files, file);
-			}
-		}
-		if (SDK_INT >= 21) {
-			for (File file : appContext.getExternalMediaDirs()) {
-				addIfNotNull(files, file);
-			}
-		}
-		for (File file : files) {
-			deleteFileOrDir(file);
-		}
 		// Recreate the cache dir as some OpenGL drivers expect it to exist
-		if (!new File(dataDir, "cache").mkdirs())
+		if (!new File(dataDir, "cache").mkdir())
 			LOG.warning("Could not recreate cache dir");
 	}
-
-	private File getDataDir() {
-		return new File(appContext.getApplicationInfo().dataDir);
-	}
-
-	private void addIfNotNull(Set<File> files, @Nullable File file) {
-		if (file != null) files.add(file);
-	}
 }

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

@@ -32,6 +32,9 @@ 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;
 
@@ -52,7 +55,7 @@ class AndroidTorPlugin extends TorPlugin {
 				appContext.getSystemService(POWER_SERVICE);
 		if (pm == null) throw new AssertionError();
 		wakeLock = new RenewableWakeLock(pm, scheduler, PARTIAL_WAKE_LOCK,
-				getWakeLockTag(), 1, MINUTES);
+				WAKE_LOCK_TAG, 1, MINUTES);
 	}
 
 	@Override
@@ -84,17 +87,4 @@ class AndroidTorPlugin extends TorPlugin {
 		super.stop();
 		wakeLock.release();
 	}
-
-	private String getWakeLockTag() {
-		PackageManager pm = appContext.getPackageManager();
-		for (PackageInfo info : pm.getInstalledPackages(0)) {
-			String name = info.packageName.toLowerCase();
-			if (name.startsWith("com.huawei.powergenie")) {
-				return "LocationManagerService";
-			} else if (name.startsWith("com.evenwell.powermonitor")) {
-				return "AudioIn";
-			}
-		}
-		return getClass().getSimpleName();
-	}
 }

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

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

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

@@ -112,8 +112,6 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 		// Other directories should be deleted
 		File potatoDir = new File(testDir, ".potato");
 		File potatoFile = new File(potatoDir, "file");
-		File filesDir = new File(testDir, "filesDir");
-		File externalCacheDir = new File(testDir, "externalCacheDir");
 
 		context.checking(new Expectations() {{
 			oneOf(prefs).edit();
@@ -128,14 +126,8 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 			will(returnValue(editor));
 			oneOf(editor).commit();
 			will(returnValue(true));
-			allowing(app).getApplicationInfo();
+			oneOf(app).getApplicationInfo();
 			will(returnValue(applicationInfo));
-			oneOf(app).getFilesDir();
-			will(returnValue(filesDir));
-			oneOf(app).getCacheDir();
-			will(returnValue(cacheDir));
-			oneOf(app).getExternalCacheDir();
-			will(returnValue(externalCacheDir));
 		}});
 
 		assertTrue(dbDir.mkdirs());
@@ -148,8 +140,6 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 		assertTrue(cacheFile.createNewFile());
 		assertTrue(potatoDir.mkdirs());
 		assertTrue(potatoFile.createNewFile());
-		assertTrue(filesDir.mkdirs());
-		assertTrue(externalCacheDir.mkdirs());
 
 		accountManager.deleteAccount();
 
@@ -163,8 +153,6 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 		assertFalse(cacheFile.exists());
 		assertFalse(potatoDir.exists());
 		assertFalse(potatoFile.exists());
-		assertFalse(filesDir.exists());
-		assertFalse(externalCacheDir.exists());
 	}
 
 	@After

bramble-android/witness.gradle

@@ -1,45 +1,47 @@
 dependencyVerification {
     verify = [
         'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
-        'com.android.tools.analytics-library:protos:26.4.0:protos-26.4.0.jar:ad760915586797d39319f402837b378bff3bb4ed583e3e0c48c965631fb2135f',
+        'com.android.tools.analytics-library:protos:26.2.1:protos-26.2.1.jar:2f371f5b1f551e85ab08be4d6a2873471b3d44afd1ebf6aa3298f3b796bf691f',
-        'com.android.tools.analytics-library:shared:26.4.0:shared-26.4.0.jar:1332106a905d48909c81268c9e414946de3e83487db394c6073b0a9b5c3d0ed2',
+        'com.android.tools.analytics-library:shared:26.2.1:shared-26.2.1.jar:4c1e4e705fa4d45f23aaea230557f6508155012d9c296337787c1d7b26a97f5a',
-        'com.android.tools.analytics-library:tracker:26.4.0:tracker-26.4.0.jar:d0020cfbfd4cd75935f2972d6a24089840d4a10df6f3ef2a796093217dd37796',
+        'com.android.tools.analytics-library:tracker:26.2.1:tracker-26.2.1.jar:4a624ecc976539f755ddb0bb8dfc2dd3d08326cfec59a098dbd70f701ca7fb75',
-        'com.android.tools.build:apksig:3.4.0:apksig-3.4.0.jar:91d5a1866139c69756280355a6f61b4d619d0516841580114f45a10f2177327e',
+        'com.android.tools.build:aapt2:3.2.1-4818971:aapt2-3.2.1-4818971-linux.jar:f431b6f96c91a2c155144b091a9c97d9805c589fe8efc9c930b6cd346cb60a1e',
-        'com.android.tools.build:apkzlib:3.4.0:apkzlib-3.4.0.jar:8653c85f5fdf1dde840e8b8af7396aeb79c34b66e541b5860059616006535592',
+        'com.android.tools.build:apksig:3.2.1:apksig-3.2.1.jar:2b46f2feffea66037aab29e4261b2433c190194a6ef97b958511eb157f2ccba5',
-        'com.android.tools.build:builder-model:3.4.0:builder-model-3.4.0.jar:a88f138124a9f016a70bcb4760359a502f65c7deed56507ee4014f4dd9ea853b',
+        'com.android.tools.build:apkzlib:3.2.1:apkzlib-3.2.1.jar:c39ad0313905932431fe81c8899c2cf39a4d92ad6c4edcaa4b25432f461452aa',
-        'com.android.tools.build:builder-test-api:3.4.0:builder-test-api-3.4.0.jar:31089ab1ec19ca7687a010867d2f3807513c805b8226979706f4247b5d4df26f',
+        'com.android.tools.build:builder-model:3.2.1:builder-model-3.2.1.jar:a9f68e6abcec122f9cb5ad352d3f05a3eb03acbcdca95e4d25c16310c2c965ff',
-        'com.android.tools.build:builder:3.4.0:builder-3.4.0.jar:476221b5203a7f50089bf185ed95000a34b6f5020ef0a17815afd58606922679',
+        'com.android.tools.build:builder-test-api:3.2.1:builder-test-api-3.2.1.jar:533ac6c2b5884bb54967a33791f2628dfdfac7981af39417a333b43d4379b6be',
-        'com.android.tools.build:gradle-api:3.4.0:gradle-api-3.4.0.jar:215eca38f6719213c2f492b4d622cdd11676c66c9871f8a2aed0c66d00175628',
+        'com.android.tools.build:builder:3.2.1:builder-3.2.1.jar:aedcbfd115dbe91d09b4113e66ef50589b558d0aa3b2f133b1d867c9b87fae83',
-        'com.android.tools.build:manifest-merger:26.4.0:manifest-merger-26.4.0.jar:29e45e690dedd165035e97c21c2ca94d0bd4ec16b6b210daa26669a582b6f220',
+        'com.android.tools.build:gradle-api:3.2.1:gradle-api-3.2.1.jar:57cf0ac5ac1dca8afdb3f62b94265e776e7dcfa641cc3844fb53a05193de208d',
-        'com.android.tools.ddms:ddmlib:26.4.0:ddmlib-26.4.0.jar:93f56fe4630c3166adbd6c51d7bb602d96abb91b07ba5b1165fdcd071e88c940',
+        'com.android.tools.build:manifest-merger:26.2.1:manifest-merger-26.2.1.jar:8830573263361035d38cfdcb51e2db94029c93865b21334f5fbf8a27984281a6',
-        'com.android.tools.external.com-intellij:intellij-core:26.4.0:intellij-core-26.4.0.jar:30cb0e879d4424de9677a50b537fb628636b4a50f5470af5e52437980c41421f',
+        'com.android.tools.ddms:ddmlib:26.2.1:ddmlib-26.2.1.jar:a4bf0a29a19980bf27269465cc782064656750b77c26728f82f9e148b705218b',
-        'com.android.tools.external.com-intellij:kotlin-compiler:26.4.0:kotlin-compiler-26.4.0.jar:dd1fe225c31a0e012dc025336363a5b783e2c5c20ffb69e77f8f57e89420d998',
+        'com.android.tools.external.com-intellij:intellij-core:26.2.1:intellij-core-26.2.1.jar:4925ad1892c2687cb1a63427d440ef519c8c59215fefe0dc5d541d5d411fcafe',
-        'com.android.tools.external.org-jetbrains:uast:26.4.0:uast-26.4.0.jar:f25f3285b775a983327583ff6584dea54e447813ef69e0ce08b05a45b5f4aab0',
+        'com.android.tools.external.com-intellij:kotlin-compiler:26.2.1:kotlin-compiler-26.2.1.jar:daa064fd708f340ee25fb9823c4c74104ac77f1370b76d907eb9ae6daec0a2ae',
-        'com.android.tools.layoutlib:layoutlib-api:26.4.0:layoutlib-api-26.4.0.jar:52128f5cf293b224072be361919bfd416e59480ab7264ddcdbbf046b0d7a12e3',
+        'com.android.tools.external.org-jetbrains:uast:26.2.1:uast-26.2.1.jar:f10f7258d2ab9189562cc0f9ad838c0378fdba439229173390a99de02ebac75b',
-        'com.android.tools.lint:lint-api:26.4.0:lint-api-26.4.0.jar:fdb8fca8ae4c254f438338d03d72605e00ed106f2d5550405af41ca1c8509401',
+        'com.android.tools.layoutlib:layoutlib-api:26.2.1:layoutlib-api-26.2.1.jar:ddbf4fca123733fa011595b1cc1f4ac2937ed327b60990711fafc33c775c2ade',
-        'com.android.tools.lint:lint-checks:26.4.0:lint-checks-26.4.0.jar:4ff52d40488cd3e22b9c6b2eb67784e0c3269d0b42ef9d17689cd75a7b2bceb4',
+        'com.android.tools.lint:lint-api:26.2.1:lint-api-26.2.1.jar:3b57e739de567b98bc9ab56c2c0ee66fc026b4adf5843e8f9804ca0666a6f66e',
-        'com.android.tools.lint:lint-gradle-api:26.4.0:lint-gradle-api-26.4.0.jar:714b7a85c7d2aa10daeab16e969fe7530c659d0728a7f24021da456870418d0f',
+        'com.android.tools.lint:lint-checks:26.2.1:lint-checks-26.2.1.jar:c86f4cc9aaee722ee4ad70062f7b5af91e9b041914af27adc09f545ab0fb3bc6',
-        'com.android.tools.lint:lint-gradle:26.4.0:lint-gradle-26.4.0.jar:b8c130d273f522388734457e1b96790f41528fcec6fda9e8eaa4e4d95a07cfbb',
+        'com.android.tools.lint:lint-gradle-api:26.2.1:lint-gradle-api-26.2.1.jar:2283e7af32e301565f2a797e531f0fc8c648077d457afb3ffdddbee638976c2f',
-        'com.android.tools.lint:lint:26.4.0:lint-26.4.0.jar:83aa062fb0405b60ed358d858c8c2955e1bae44a455b498068c6a60988755f00',
+        'com.android.tools.lint:lint-gradle:26.2.1:lint-gradle-26.2.1.jar:8fd90b2f3ec788cbb9801c07ab3e1ea2255aa31a6093157d7ea0ff13d0315ecb',
-        'com.android.tools:annotations:26.4.0:annotations-26.4.0.jar:a7955b8e19c3a2a861d6faa43a58b7c0d46ea9112188ee3e235c6f9f439ecc1a',
+        'com.android.tools.lint:lint-kotlin:26.2.1:lint-kotlin-26.2.1.jar:7a6a5d2b18f69cf1b900d857c2632b4c683713c533295933b8b759f8cab4a877',
-        'com.android.tools:common:26.4.0:common-26.4.0.jar:ea40b94b3c1284ea7700f011388e2906a8363a66abd902891722b3c557984852',
+        'com.android.tools.lint:lint:26.2.1:lint-26.2.1.jar:7848b82ae988b90dee259ae7c7e86e05cbf52db6cd21c8bbd38ce7df08f3f8c5',
-        'com.android.tools:dvlib:26.4.0:dvlib-26.4.0.jar:23af89c535b01ba36ceed1b6b309b672814eba624e643cd7dedf0519edad50cc',
+        'com.android.tools:annotations:26.2.1:annotations-26.2.1.jar:7391c6a1e080174b96e64ceb078dadd31ce4d8a2d2fee0ec65be202126f90f24',
-        'com.android.tools:repository:26.4.0:repository-26.4.0.jar:3d1763ab46199374dc6d94129bba11c70f1d5857e2c81a3ac4898abca40b176b',
+        'com.android.tools:common:26.2.1:common-26.2.1.jar:a50aab2d6411ff68f4004a87c7e93d87d8e980a0ec3b352246549897ea2d78e5',
-        'com.android.tools:sdk-common:26.4.0:sdk-common-26.4.0.jar:78a522525b30ffc6b7bf1299c831d24ce385f68a9f4878f8f752e9baefa31b0f',
+        'com.android.tools:dvlib:26.2.1:dvlib-26.2.1.jar:72a83bf2839b1df9b1fbf67ba45d1bfb9f966cd774da4320c762b2be8f1688aa',
-        'com.android.tools:sdklib:26.4.0:sdklib-26.4.0.jar:b854c23892013a326d761cf071c72cf3e038ed0469d10f4a356829fa56e4c132',
+        '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.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:2.22.1:dagger-compiler-2.22.1.jar:e5f28302cbe70a79d3620cddebfb8ec0736814f3980ffe1e673bfe3342f507d3',
+        'com.google.dagger:dagger-compiler:2.19:dagger-compiler-2.19.jar:27a4b202a2de908182edb261f8c0a264e08e5e4733d7514bc7fbf0d31da5c0fc',
-        'com.google.dagger:dagger-producers:2.22.1:dagger-producers-2.22.1.jar:f834a0082014213a68ff06a0f048d750178d02196c58b0b15beb367d32b97e35',
+        'com.google.dagger:dagger-producers:2.19:dagger-producers-2.19.jar:a17663abe0fc38b676026950907d4c5f5e2bf338375415861eaff6e3bdb0b768',
-        'com.google.dagger:dagger-spi:2.22.1:dagger-spi-2.22.1.jar:4b0b922793b3bcb91b99fabb75dba77c68afd7ae4c5f0c4fd6ba681f0a291c7d',
+        'com.google.dagger:dagger-spi:2.19:dagger-spi-2.19.jar:e7a6379d82c841f6aac2866948ad1eed716528707814602842a8d844ce04e2e1',
-        'com.google.dagger:dagger:2.22.1:dagger-2.22.1.jar:329d4340f24c4f5717af016c097e90668bfea2a5376e6aa9964b01cef3fd241a',
+        '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.j2objc:j2objc-annotations:1.1:j2objc-annotations-1.1.jar:2994a7eb78f2710bd3d3bfb639b2c94e219cedac0d4d084d516e78c16dddecf6',
         'com.google.jimfs:jimfs:1.1:jimfs-1.1.jar:c4828e28d7c0a930af9387510b3bada7daa5c04d7c25a75c7b8b081f1c257ddd',
         'com.google.protobuf:protobuf-java:3.4.0:protobuf-java-3.4.0.jar:dce7e66b32456a1b1198da0caff3a8acb71548658391e798c79369241e6490a4',
         'com.googlecode.json-simple:json-simple:1.1:json-simple-1.1.jar:2d9484f4c649f708f47f9a479465fc729770ee65617dca3011836602264f6439',
@@ -48,7 +50,7 @@ dependencyVerification {
         'com.sun.activation:javax.activation:1.2.0:javax.activation-1.2.0.jar:993302b16cd7056f21e779cc577d175a810bb4900ef73cd8fbf2b50f928ba9ce',
         'com.sun.istack:istack-commons-runtime:2.21:istack-commons-runtime-2.21.jar:c33e67a0807095f02a0e2da139412dd7c4f9cc1a4c054b3e434f96831ba950f4',
         'com.sun.xml.fastinfoset:FastInfoset:1.2.13:FastInfoset-1.2.13.jar:27a77db909f3c2833c0b1a37c55af1db06045118ad2eed96ce567b6632bce038',
-        'commons-codec:commons-codec:1.10:commons-codec-1.10.jar:4241dfa94e711d435f29a4604a3e2de5c4aa3c165e23bd066be6fc1fc4309569',
+        'commons-codec:commons-codec:1.9:commons-codec-1.9.jar:ad19d2601c3abf0b946b5c3a4113e226a8c1e3305e395b90013b78dd94a723ce',
         'commons-logging:commons-logging:1.2:commons-logging-1.2.jar:daddea1ea0be0f56978ab3006b8ac92834afeefbd9b7e4e6316fca57df0fa636',
         'it.unimi.dsi:fastutil:7.2.0:fastutil-7.2.0.jar:74fa208043740642f7e6eb09faba15965218ad2f50ce3020efb100136e4b591c',
         'javax.annotation:jsr250-api:1.0:jsr250-api-1.0.jar:a1a922d0d9b6d183ed3800dfac01d1e1eb159f0e8c6f94736931c1def54a941f',
@@ -60,28 +62,27 @@ dependencyVerification {
         'org.apache.ant:ant-launcher:1.9.4:ant-launcher-1.9.4.jar:7bccea20b41801ca17bcbc909a78c835d0f443f12d639c77bd6ae3d05861608d',
         'org.apache.ant:ant:1.9.4:ant-1.9.4.jar:649ae0730251de07b8913f49286d46bba7b92d47c5f332610aa426c4f02161d8',
         'org.apache.commons:commons-compress:1.12:commons-compress-1.12.jar:2c1542faf343185b7cab9c3d55c8ae5471d6d095d3887a4adefdbdf2984dc0b6',
-        'org.apache.httpcomponents:httpclient:4.5.6:httpclient-4.5.6.jar:c03f813195e7a80e3608d0ddd8da80b21696a4c92a6a2298865bf149071551c7',
+        'org.apache.httpcomponents:httpclient:4.5.2:httpclient-4.5.2.jar:0dffc621400d6c632f55787d996b8aeca36b30746a716e079a985f24d8074057',
-        'org.apache.httpcomponents:httpcore:4.4.10:httpcore-4.4.10.jar:78ba1096561957db1b55200a159b648876430342d15d461277e62360da19f6fd',
+        'org.apache.httpcomponents:httpcore:4.4.5:httpcore-4.4.5.jar:64d5453874cab7e40a7065cb01a9a9ca1053845a9786b478878b679e0580cec3',
-        'org.apache.httpcomponents:httpmime:4.5.6:httpmime-4.5.6.jar:0b2b1102c18d3c7e05a77214b9b7501a6f6056174ae5604e0e256776eda7553e',
+        'org.apache.httpcomponents:httpmime:4.5.2:httpmime-4.5.2.jar:231a3f7e4962053db2be8461d5422e68fc458a3a7dd7d8ada803a348e21f8f07',
         'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
         'org.bouncycastle:bcpkix-jdk15on:1.56:bcpkix-jdk15on-1.56.jar:7043dee4e9e7175e93e0b36f45b1ec1ecb893c5f755667e8b916eb8dd201c6ca',
         'org.bouncycastle:bcprov-jdk15on:1.56:bcprov-jdk15on-1.56.jar:963e1ee14f808ffb99897d848ddcdb28fa91ddda867eb18d303e82728f878349',
-        'org.briarproject:obfs4proxy-android:0.0.9:obfs4proxy-android-0.0.9.zip:9b7e9181535ea8d8bbe8ae6338e08cf4c5fc1e357a779393e0ce49586d459ae0',
+        'org.briarproject:obfs4proxy-android:0.0.7:obfs4proxy-android-0.0.7.zip:abdfb5d889d848de9bf214f9276abbf454808a505b870819eccc9a9e985bf617',
-        'org.briarproject:tor-android:0.3.5.8:tor-android-0.3.5.8.zip:42a13a6f185be1a62f42e3f30ce66a3c099ac5ec890a65e7593111b65b44a54a',
+        'org.briarproject:tor-android:0.3.4.8:tor-android-0.3.4.8.zip:989a0352d9d8d8172cd6c2137654e165e5d2beb10ed1211bab3814e224ad1926',
         'org.checkerframework:checker-compat-qual:2.5.3:checker-compat-qual-2.5.3.jar:d76b9afea61c7c082908023f0cbc1427fab9abd2df915c8b8a3e7a509bccbc6d',
-        'org.checkerframework:checker-qual:2.5.2:checker-qual-2.5.2.jar:64b02691c8b9d4e7700f8ee2e742dce7ea2c6e81e662b7522c9ee3bf568c040a',
+        'org.codehaus.groovy:groovy-all:2.4.12:groovy-all-2.4.12.jar:6a56af4bd48903d56bec62821876cadefafd007360cc6bd0d8f7aa8d72b38be4',
-        'org.codehaus.groovy:groovy-all:2.4.15:groovy-all-2.4.15.jar:51d6c4e71782e85674239189499854359d380fb75e1a703756e3aaa5b98a5af0',
         'org.codehaus.mojo:animal-sniffer-annotations:1.14:animal-sniffer-annotations-1.14.jar:2068320bd6bad744c3673ab048f67e30bef8f518996fa380033556600669905d',
         'org.glassfish.jaxb:jaxb-core:2.2.11:jaxb-core-2.2.11.jar:37bcaee8ebb04362c8352a5bf6221b86967ecdab5164c696b10b9a2bb587b2aa',
         'org.glassfish.jaxb:jaxb-runtime:2.2.11:jaxb-runtime-2.2.11.jar:a874f2351cfba8e2946be3002d10c18a6da8f21b52ba2acf52f2b85d5520ed70',
         'org.glassfish.jaxb:txw2:2.2.11:txw2-2.2.11.jar:272a3ccad45a4511351920cd2a8633c53cab8d5220c7a92954da5526bb5eafea',
         'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
         'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
-        'org.jetbrains.kotlin:kotlin-reflect:1.3.21:kotlin-reflect-1.3.21.jar:a3065c822633191e0a3e3ee12a29bec234fc4b2864a6bb87ef48cce3e9e0c26a',
+        'org.jetbrains.kotlin:kotlin-reflect:1.2.0:kotlin-reflect-1.2.0.jar:4f48a872bad6e4d9c053f4ad610d11e4012ad7e58dc19a03dd5eb811f36069dd',
-        'org.jetbrains.kotlin:kotlin-stdlib-common:1.3.21:kotlin-stdlib-common-1.3.21.jar:cea61f7b611895e64f58569a9757fc0ab0d582f107211e1930e0ce2a0add52a7',
+        'org.jetbrains.kotlin:kotlin-stdlib-common:1.2.71:kotlin-stdlib-common-1.2.71.jar:63999687ff2fce8a592dd180ffbbf8f1d21c26b4044c55cdc74ff3cf3b3cf328',
-        'org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.3.21:kotlin-stdlib-jdk7-1.3.21.jar:a87875604fd42140da6938ae4d35ee61081f4482536efc6d2615b8b626a198af',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.2.71:kotlin-stdlib-jdk7-1.2.71.jar:b136bd61b240e07d4d92ce00d3bd1dbf584400a7bf5f220c2f3cd22446858082',
-        'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.3.21:kotlin-stdlib-jdk8-1.3.21.jar:5823ed66ac122a1c55442ebca5a209a843ccd87f562edc31a787f3d2e47f74d4',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.2.71:kotlin-stdlib-jdk8-1.2.71.jar:ac3c8abf47790b64b4f7e2509a53f0c145e061ac1612a597520535d199946ea9',
-        'org.jetbrains.kotlin:kotlin-stdlib:1.3.21:kotlin-stdlib-1.3.21.jar:38ba2370d9f06f50433e06b2ca775b94473c2e2785f410926079ab793c72b034',
+        'org.jetbrains.kotlin:kotlin-stdlib:1.2.71:kotlin-stdlib-1.2.71.jar:4c895c270b87f5fec2a2796e1d89c15407ee821de961527c28588bb46afbc68b',
         'org.jetbrains.trove4j:trove4j:20160824:trove4j-20160824.jar:1917871c8deb468307a584680c87a44572f5a8b0b98c6d397fc0f5f86596dbe7',
         'org.jetbrains:annotations:13.0:annotations-13.0.jar:ace2a10dc8e2d5fd34925ecac03e4988b2c0f851650c94b8cef49ba1bd111478',
         'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',

bramble-api/build.gradle

@@ -7,7 +7,7 @@ apply plugin: 'witness'
 apply from: 'witness.gradle'
 
 dependencies {
-	implementation "com.google.dagger:dagger:2.22.1"
+	implementation "com.google.dagger:dagger:2.19"
 	implementation 'com.google.code.findbugs:jsr305:3.0.2'
 
 	testImplementation 'junit:junit:4.12'

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

@@ -6,7 +6,6 @@ import org.briarproject.bramble.util.StringUtils;
 import java.util.Arrays;
 import java.util.Comparator;
 
-import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 
 /**
@@ -39,7 +38,7 @@ public class Bytes implements Comparable<Bytes> {
 	}
 
 	@Override
-	public boolean equals(@Nullable Object o) {
+	public boolean equals(Object o) {
 		return o instanceof Bytes && Arrays.equals(bytes, ((Bytes) o).bytes);
 	}
 

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

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

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

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

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

@@ -1,8 +1,6 @@
 package org.briarproject.bramble.api.client;
 
 import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.crypto.PrivateKey;
-import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.data.BdfDictionary;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.db.DbException;
@@ -98,18 +96,14 @@ public interface ClientHelper {
 
 	BdfList toList(Author a);
 
-	byte[] sign(String label, BdfList toSign, PrivateKey privateKey)
+	byte[] sign(String label, BdfList toSign, byte[] privateKey)
 			throws FormatException, GeneralSecurityException;
 
 	void verifySignature(byte[] signature, String label, BdfList signed,
-			PublicKey publicKey)
+			byte[] publicKey) throws FormatException, GeneralSecurityException;
-			throws FormatException, GeneralSecurityException;
 
 	Author parseAndValidateAuthor(BdfList author) throws FormatException;
 
-	PublicKey parseAndValidateAgreementPublicKey(byte[] publicKeyBytes)
-		throws FormatException;
-
 	TransportProperties parseAndValidateTransportProperties(
 			BdfDictionary properties) throws FormatException;
 

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

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

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

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

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

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

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

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

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

@@ -1,10 +1,7 @@
 package org.briarproject.bramble.api.contact;
 
-import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.UnsupportedVersionException;
 import org.briarproject.bramble.api.crypto.SecretKey;
 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;
@@ -16,6 +13,8 @@ import java.util.Collection;
 
 import javax.annotation.Nullable;
 
+import static org.briarproject.bramble.api.contact.PendingContact.PendingContactState.FAILED;
+
 @NotNullByDefault
 public interface ContactManager {
 
@@ -34,7 +33,7 @@ public interface ContactManager {
 	 * @param alice true if the local party is Alice
 	 */
 	ContactId addContact(Transaction txn, Author remote, AuthorId local,
-			SecretKey rootKey, long timestamp, boolean alice, boolean verified,
+			SecretKey master, long timestamp, boolean alice, boolean verified,
 			boolean active) throws DbException;
 
 	/**
@@ -42,7 +41,7 @@ public interface ContactManager {
 	 * and returns an ID for the contact.
 	 */
 	ContactId addContact(Transaction txn, Author remote, AuthorId local,
-			boolean verified) throws DbException;
+			boolean verified, boolean active) throws DbException;
 
 	/**
 	 * Stores a contact associated with the given local and remote pseudonyms,
@@ -51,39 +50,38 @@ public interface ContactManager {
 	 *
 	 * @param alice true if the local party is Alice
 	 */
-	ContactId addContact(Author remote, AuthorId local, SecretKey rootKey,
+	ContactId addContact(Author remote, AuthorId local, SecretKey master,
 			long timestamp, boolean alice, boolean verified, boolean active)
 			throws DbException;
 
 	/**
-	 * Returns the handshake link that needs to be sent to a contact we want
+	 * Returns the static link that needs to be sent to the contact to be added.
-	 * to add.
 	 */
-	String getHandshakeLink() throws DbException;
+	String getRemoteContactLink();
 
 	/**
-	 * Creates a {@link PendingContact} from the given handshake link and
+	 * Returns true if the given link is syntactically valid.
-	 * alias, adds it to the database and returns it.
-	 *
-	 * @param link The handshake 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
-	 * @throws UnsupportedVersionException If the link uses a format version
-	 * that is not supported
-	 * @throws FormatException If the link is invalid
 	 */
-	PendingContact addPendingContact(String link, String alias)
+	boolean isValidRemoteContactLink(String link);
-			throws DbException, FormatException;
+
+	/**
+	 * 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() throws DbException;
+	Collection<PendingContact> getPendingContacts();
 
 	/**
-	 * Removes a {@link PendingContact}.
+	 * Removes a {@link PendingContact} that is in state {@link FAILED}.
 	 */
-	void removePendingContact(PendingContactId p) throws DbException;
+	void removePendingContact(PendingContact pendingContact);
 
 	/**
 	 * Returns the contact with the given ID.
@@ -94,7 +92,7 @@ public interface ContactManager {
 	 * Returns the contact with the given remoteAuthorId
 	 * that was added by the LocalAuthor with the given localAuthorId
 	 *
-	 * @throws NoSuchContactException If the contact is not in the database
+	 * @throws org.briarproject.bramble.api.db.NoSuchContactException
 	 */
 	Contact getContact(AuthorId remoteAuthorId, AuthorId localAuthorId)
 			throws DbException;
@@ -103,7 +101,7 @@ public interface ContactManager {
 	 * Returns the contact with the given remoteAuthorId
 	 * that was added by the LocalAuthor with the given localAuthorId
 	 *
-	 * @throws NoSuchContactException If the contact is not in the database
+	 * @throws org.briarproject.bramble.api.db.NoSuchContactException
 	 */
 	Contact getContact(Transaction txn, AuthorId remoteAuthorId,
 			AuthorId localAuthorId) throws DbException;
@@ -111,7 +109,7 @@ public interface ContactManager {
 	/**
 	 * Returns all active contacts.
 	 */
-	Collection<Contact> getContacts() throws DbException;
+	Collection<Contact> getActiveContacts() throws DbException;
 
 	/**
 	 * Removes a contact and all associated state.
@@ -123,6 +121,12 @@ 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.
 	 */
@@ -159,20 +163,8 @@ public interface ContactManager {
 
 	interface ContactHook {
 
-		/**
-		 * Called when a contact is being added.
-		 *
-		 * @param txn A read-write transaction
-		 * @param c The contact that is being added
-		 */
 		void addingContact(Transaction txn, Contact c) throws DbException;
 
-		/**
-		 * Called when a contact is being removed
-		 *
-		 * @param txn A read-write transaction
-		 * @param c The contact that is being removed
-		 */
 		void removingContact(Transaction txn, Contact c) throws DbException;
 	}
 }

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

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

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

@@ -1,6 +1,5 @@
 package org.briarproject.bramble.api.contact;
 
-import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import javax.annotation.concurrent.Immutable;
@@ -9,29 +8,26 @@ import javax.annotation.concurrent.Immutable;
 @NotNullByDefault
 public class PendingContact {
 
+	public enum PendingContactState {
+		WAITING_FOR_CONNECTION,
+		CONNECTED,
+		ADDING_CONTACT,
+		FAILED
+	}
+
 	private final PendingContactId id;
-	private final PublicKey publicKey;
 	private final String alias;
 	private final PendingContactState state;
 	private final long timestamp;
 
-	public PendingContact(PendingContactId id, PublicKey publicKey,
+	public PendingContact(PendingContactId id, String alias,
-			String alias, PendingContactState state, long timestamp) {
+			PendingContactState state, long timestamp) {
 		this.id = id;
-		this.publicKey = publicKey;
 		this.alias = alias;
 		this.state = state;
 		this.timestamp = timestamp;
 	}
 
-	public PendingContactId getId() {
-		return id;
-	}
-
-	public PublicKey getPublicKey() {
-		return publicKey;
-	}
-
 	public String getAlias() {
 		return alias;
 	}
@@ -54,4 +50,5 @@ public class PendingContact {
 		return o instanceof PendingContact &&
 				id.equals(((PendingContact) o).id);
 	}
+
 }

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

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

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

@@ -1,30 +0,0 @@
-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

@@ -14,12 +14,18 @@ import javax.annotation.concurrent.Immutable;
 public class ContactAddedEvent extends Event {
 
 	private final ContactId contactId;
+	private final boolean active;
 
-	public ContactAddedEvent(ContactId contactId) {
+	public ContactAddedEvent(ContactId contactId, boolean active) {
 		this.contactId = contactId;
+		this.active = active;
 	}
 
 	public ContactId getContactId() {
 		return contactId;
 	}
+
+	public boolean isActive() {
+		return active;
+	}
 }

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

@@ -1,32 +0,0 @@
-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

@@ -1,20 +0,0 @@
-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

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

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

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

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

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

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

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

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

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

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

@@ -55,7 +55,7 @@ public interface CryptoComponent {
 	 * signature, to prevent it from being repurposed or colliding with a
 	 * signature created for another purpose
 	 */
-	byte[] sign(String label, byte[] toSign, PrivateKey privateKey)
+	byte[] sign(String label, byte[] toSign, byte[] privateKey)
 			throws GeneralSecurityException;
 
 	/**
@@ -68,7 +68,7 @@ public interface CryptoComponent {
 	 * @return true if the signature was valid, false otherwise.
 	 */
 	boolean verifySignature(byte[] signature, String label, byte[] signed,
-			PublicKey publicKey) throws GeneralSecurityException;
+			byte[] publicKey) throws GeneralSecurityException;
 
 	/**
 	 * Returns the hash of the given inputs. The inputs are unambiguously

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

@@ -5,34 +5,25 @@ import org.briarproject.bramble.api.transport.TransportKeys;
 
 /**
  * Crypto operations for the transport security protocol - see
- * https://code.briarproject.org/briar/briar-spec/blob/master/protocols/BTP.md
+ * https://code.briarproject.org/akwizgran/briar-spec/blob/master/protocols/BTP.md
  */
 public interface TransportCrypto {
 
 	/**
-	 * Derives initial rotation mode transport keys for the given transport in
+	 * Derives initial transport keys for the given transport in the given
-	 * the given time period from the given root key.
+	 * rotation period from the given master secret.
 	 *
-	 * @param alice Whether the keys are for use by Alice or Bob
+	 * @param alice whether the keys are for use by Alice or Bob.
-	 * @param active Whether the keys are usable for outgoing streams
+	 * @param active whether the keys are usable for outgoing streams.
 	 */
-	TransportKeys deriveRotationKeys(TransportId t, SecretKey rootKey,
+	TransportKeys deriveTransportKeys(TransportId t, SecretKey master,
-			long timePeriod, boolean alice, boolean active);
+			long rotationPeriod, boolean alice, boolean active);
 
 	/**
-	 * Derives handshake keys for the given transport in the given time period
+	 * Rotates the given transport keys to the given rotation period. If the
-	 * from the given root key.
+	 * keys are for the given period or any later period they are not rotated.
-	 *
-	 * @param alice Whether the keys are for use by Alice or Bob
 	 */
-	TransportKeys deriveHandshakeKeys(TransportId t, SecretKey rootKey,
+	TransportKeys rotateTransportKeys(TransportKeys k, long rotationPeriod);
-			long timePeriod, boolean alice);
-
-	/**
-	 * Updates the given transport keys to the given time period. If the keys
-	 * are for the given period or any later period they are not updated.
-	 */
-	TransportKeys updateTransportKeys(TransportKeys k, long timePeriod);
 
 	/**
 	 * Encodes the pseudo-random tag that is used to recognise a stream.

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

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

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

@@ -2,14 +2,10 @@ package org.briarproject.bramble.api.db;
 
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.contact.PendingContact;
-import org.briarproject.bramble.api.contact.PendingContactId;
-import org.briarproject.bramble.api.crypto.PrivateKey;
-import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
-import org.briarproject.bramble.api.identity.Identity;
+import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.settings.Settings;
@@ -24,8 +20,8 @@ import org.briarproject.bramble.api.sync.MessageStatus;
 import org.briarproject.bramble.api.sync.Offer;
 import org.briarproject.bramble.api.sync.Request;
 import org.briarproject.bramble.api.sync.validation.MessageState;
+import org.briarproject.bramble.api.transport.KeySet;
 import org.briarproject.bramble.api.transport.KeySetId;
-import org.briarproject.bramble.api.transport.TransportKeySet;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.util.Collection;
@@ -105,7 +101,7 @@ public interface DatabaseComponent {
 	 * and returns an ID for the contact.
 	 */
 	ContactId addContact(Transaction txn, Author remote, AuthorId local,
-			boolean verified) throws DbException;
+			boolean verified, boolean active) throws DbException;
 
 	/**
 	 * Stores a group.
@@ -113,9 +109,9 @@ public interface DatabaseComponent {
 	void addGroup(Transaction txn, Group g) throws DbException;
 
 	/**
-	 * Stores an identity.
+	 * Stores a local pseudonym.
 	 */
-	void addIdentity(Transaction txn, Identity i) throws DbException;
+	void addLocalAuthor(Transaction txn, LocalAuthor a) throws DbException;
 
 	/**
 	 * Stores a local message.
@@ -123,12 +119,6 @@ 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.
 	 */
@@ -139,46 +129,25 @@ public interface DatabaseComponent {
 	 * Stores the given transport keys for the given contact and returns a
 	 * key set ID.
 	 */
-	KeySetId addTransportKeys(Transaction txn, ContactId c, TransportKeys k)
+	KeySetId addTransportKeys(Transaction txn, ContactId c,
-			throws DbException;
-
-	/**
-	 * Stores the given transport keys for the given pending contact and
-	 * returns a key set ID.
-	 */
-	KeySetId addTransportKeys(Transaction txn, PendingContactId p,
 			TransportKeys k) throws DbException;
 
 	/**
 	 * Returns true if the database contains the given contact for the given
 	 * local pseudonym.
-	 * <p/>
-	 * Read-only.
 	 */
 	boolean containsContact(Transaction txn, AuthorId remote, AuthorId local)
 			throws DbException;
 
 	/**
 	 * Returns true if the database contains the given group.
-	 * <p/>
-	 * Read-only.
 	 */
 	boolean containsGroup(Transaction txn, GroupId g) throws DbException;
 
 	/**
-	 * Returns true if the database contains an identity for the given
+	 * Returns true if the database contains the given local author.
-	 * pseudonym.
-	 * <p/>
-	 * Read-only.
 	 */
-	boolean containsIdentity(Transaction txn, AuthorId a) throws DbException;
+	boolean containsLocalAuthor(Transaction txn, AuthorId local)
-
-	/**
-	 * Returns true if the database contains the given pending contact.
-	 * <p/>
-	 * Read-only.
-	 */
-	boolean containsPendingContact(Transaction txn, PendingContactId p)
 			throws DbException;
 
 	/**
@@ -266,7 +235,7 @@ public interface DatabaseComponent {
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<ContactId> getContacts(Transaction txn, AuthorId local)
+	Collection<ContactId> getContacts(Transaction txn, AuthorId a)
 			throws DbException;
 
 	/**
@@ -301,18 +270,18 @@ public interface DatabaseComponent {
 			throws DbException;
 
 	/**
-	 * Returns the identity for the local pseudonym with the given ID.
+	 * Returns the local pseudonym with the given ID.
 	 * <p/>
 	 * Read-only.
 	 */
-	Identity getIdentity(Transaction txn, AuthorId a) throws DbException;
+	LocalAuthor getLocalAuthor(Transaction txn, AuthorId a) throws DbException;
 
 	/**
-	 * Returns the identities for all local pseudonyms.
+	 * Returns all local pseudonyms.
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<Identity> getIdentities(Transaction txn) throws DbException;
+	Collection<LocalAuthor> getLocalAuthors(Transaction txn) throws DbException;
 
 	/**
 	 * Returns the message with the given ID.
@@ -448,14 +417,6 @@ 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/>
@@ -468,7 +429,7 @@ public interface DatabaseComponent {
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<TransportKeySet> getTransportKeys(Transaction txn, TransportId t)
+	Collection<KeySet> getTransportKeys(Transaction txn, TransportId t)
 			throws DbException;
 
 	/**
@@ -531,21 +492,15 @@ public interface DatabaseComponent {
 	void removeGroup(Transaction txn, Group g) throws DbException;
 
 	/**
-	 * Removes an identity (and all associated state) from the database.
+	 * Removes a local pseudonym (and all associated state) from the database.
 	 */
-	void removeIdentity(Transaction txn, AuthorId a) throws DbException;
+	void removeLocalAuthor(Transaction txn, AuthorId a) throws DbException;
 
 	/**
 	 * Removes a message (and all associated state) from the database.
 	 */
 	void removeMessage(Transaction txn, MessageId m) throws DbException;
 
-	/**
-	 * Removes a pending contact (and all associated state) from the database.
-	 */
-	void removePendingContact(Transaction txn, PendingContactId p)
-			throws DbException;
-
 	/**
 	 * Removes a transport (and all associated state) from the database.
 	 */
@@ -562,6 +517,12 @@ public interface DatabaseComponent {
 	 */
 	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.
 	 */
@@ -592,17 +553,11 @@ public interface DatabaseComponent {
 			Collection<MessageId> dependencies) throws DbException;
 
 	/**
-	 * Sets the handshake key pair for the identity with the given ID.
+	 * Sets the reordering window for the given key set and transport in the
-	 */
+	 * given rotation period.
-	void setHandshakeKeyPair(Transaction txn, AuthorId local,
-			PublicKey publicKey, PrivateKey privateKey) throws DbException;
-
-	/**
-	 * Sets the reordering window for the given transport keys in the given
-	 * time period.
 	 */
 	void setReorderingWindow(Transaction txn, KeySetId k, TransportId t,
-			long timePeriod, long base, byte[] bitmap) throws DbException;
+			long rotationPeriod, long base, byte[] bitmap) throws DbException;
 
 	/**
 	 * Marks the given transport keys as usable for outgoing streams.
@@ -613,6 +568,6 @@ public interface DatabaseComponent {
 	/**
 	 * Stores the given transport keys, deleting any keys they have replaced.
 	 */
-	void updateTransportKeys(Transaction txn, Collection<TransportKeySet> keys)
+	void updateTransportKeys(Transaction txn, Collection<KeySet> keys)
 			throws DbException;
 }

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

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

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

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

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

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

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

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

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

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

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

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

@@ -1,15 +1,13 @@
 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.
  */
@@ -19,7 +17,7 @@ public class Transaction {
 	private final Object txn;
 	private final boolean readOnly;
 
-	private List<CommitAction> actions = null;
+	private List<Event> events = null;
 	private boolean committed = false;
 
 	public Transaction(Object txn, boolean readOnly) {
@@ -44,27 +42,19 @@ public class Transaction {
 
 	/**
 	 * Attaches an event to be broadcast when the transaction has been
-	 * committed. The event will be broadcast on the {@link EventExecutor}.
+	 * committed.
 	 */
 	public void attach(Event e) {
-		if (actions == null) actions = new ArrayList<>();
+		if (events == null) events = new ArrayList<>();
-		actions.add(new EventAction(e));
+		events.add(e);
 	}
 
 	/**
-	 * Attaches a task to be executed when the transaction has been
+	 * Returns any events attached to the transaction.
-	 * committed. The task will be run on the {@link EventExecutor}.
 	 */
-	public void attach(Runnable r) {
+	public List<Event> getEvents() {
-		if (actions == null) actions = new ArrayList<>();
+		if (events == null) return Collections.emptyList();
-		actions.add(new TaskAction(r));
+		return events;
-	}
-
-	/**
-	 * Returns any actions attached to the transaction.
-	 */
-	public List<CommitAction> getActions() {
-		return actions == null ? emptyList() : actions;
 	}
 
 	/**

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

@@ -6,20 +6,10 @@ import javax.annotation.Nullable;
 public class NullSafety {
 
 	/**
-	 * Stand-in for {@code Objects.requireNonNull()}.
+	 * Stand-in for `Objects.requireNonNull()`.
 	 */
 	public static <T> T requireNonNull(@Nullable T t) {
 		if (t == null) throw new NullPointerException();
 		return t;
 	}
-
-	/**
-	 * Checks that exactly one of the arguments is null.
-	 *
-	 * @throws AssertionError If both or neither of the arguments are null
-	 */
-	public static void requireExactlyOneNull(@Nullable Object a,
-			@Nullable Object b) {
-		if ((a == null) == (b == null)) throw new AssertionError();
-	}
 }

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

@@ -0,0 +1,14 @@
+package org.briarproject.bramble.api.sync;
+
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface Client {
+
+	/**
+	 * Called at startup to create any local state needed by the client.
+	 */
+	void createLocalState(Transaction txn) throws DbException;
+}

bramble-api/src/main/java/org/briarproject/bramble/api/sync/validation/IncomingMessageHook.java

@@ -11,8 +11,7 @@ public interface IncomingMessageHook {
 	/**
 	 * Called once for each incoming message that passes validation.
 	 *
-	 * @param txn A read-write transaction
+	 * @return whether or not this message should be shared
-	 * @return Whether or not this message should be shared
 	 * @throws DbException Should only be used for real database errors.
 	 * If this is thrown, delivery will be attempted again at next startup,
 	 * whereas if an InvalidMessageException is thrown,

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

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

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

@@ -1,7 +1,6 @@
 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.crypto.SecretKey;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
@@ -19,45 +18,17 @@ public interface KeyManager {
 
 	/**
 	 * Informs the key manager that a new contact has been added. Derives and
-	 * stores a set of rotation mode transport keys for communicating with the
+	 * stores a set of transport keys for communicating with the contact over
-	 * contact over each transport and returns the key set IDs.
+	 * each transport and returns the key set IDs.
 	 * <p/>
 	 * {@link StreamContext StreamContexts} for the contact can be created
 	 * after this method has returned.
 	 *
-	 * @param alice True if the local party is Alice
+	 * @param alice true if the local party is Alice
-	 * @param active Whether the derived keys can be used for outgoing streams
+	 * @param active whether the derived keys can be used for outgoing streams
 	 */
-	Map<TransportId, KeySetId> addContactWithRotationKeys(Transaction txn,
+	Map<TransportId, KeySetId> addContact(Transaction txn, ContactId c,
-			ContactId c, SecretKey rootKey, long timestamp, boolean alice,
+			SecretKey master, long timestamp, boolean alice, boolean active)
-			boolean active) throws DbException;
-
-	/**
-	 * Informs the key manager that a new contact has been added. Derives and
-	 * stores a set of handshake mode transport keys for communicating with the
-	 * contact over each transport and returns the key set IDs.
-	 * <p/>
-	 * {@link StreamContext StreamContexts} for the contact can be created
-	 * after this method has returned.
-	 *
-	 * @param alice True if the local party is Alice
-	 */
-	Map<TransportId, KeySetId> addContactWithHandshakeKeys(Transaction txn,
-			ContactId c, SecretKey rootKey, boolean alice) throws DbException;
-
-	/**
-	 * Informs the key manager that a new pending contact has been added.
-	 * Derives and stores a set of handshake mode transport keys for
-	 * communicating with the pending contact over each transport and returns
-	 * the key set IDs.
-	 * <p/>
-	 * {@link StreamContext StreamContexts} for the pending contact can be
-	 * created after this method has returned.
-	 *
-	 * @param alice True if the local party is Alice
-	 */
-	Map<TransportId, KeySetId> addPendingContact(Transaction txn,
-			PendingContactId p, SecretKey rootKey, boolean alice)
 			throws DbException;
 
 	/**
@@ -72,28 +43,15 @@ public interface KeyManager {
 	 */
 	boolean canSendOutgoingStreams(ContactId c, TransportId t);
 
-	/**
-	 * Returns true if we have keys that can be used for outgoing streams to
-	 * the given pending contact over the given transport.
-	 */
-	boolean canSendOutgoingStreams(PendingContactId p, TransportId t);
-
 	/**
 	 * Returns a {@link StreamContext} for sending a stream to the given
-	 * contact over the given transport, or null if an error occurs.
+	 * contact over the given transport, or null if an error occurs or the
+	 * contact does not support the transport.
 	 */
 	@Nullable
 	StreamContext getStreamContext(ContactId c, TransportId t)
 			throws DbException;
 
-	/**
-	 * Returns a {@link StreamContext} for sending a stream to the given
-	 * pending contact over the given transport, or null if an error occurs.
-	 */
-	@Nullable
-	StreamContext getStreamContext(PendingContactId p, TransportId t)
-			throws DbException;
-
 	/**
 	 * Looks up the given tag and returns a {@link StreamContext} for reading
 	 * from the corresponding stream, or null if an error occurs or the tag was

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

@@ -0,0 +1,47 @@
+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/KeySetId.java

@@ -5,8 +5,10 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import javax.annotation.concurrent.Immutable;
 
 /**
- * Type-safe wrapper for an integer that uniquely identifies a set of
+ * Type-safe wrapper for an integer that uniquely identifies a set of transport
- * {@link TransportKeySet transport keys} within the scope of the local device.
+ * keys within the scope of the local device.
+ * <p/>
+ * Key sets created on a given device must have increasing identifiers.
  */
 @Immutable
 @NotNullByDefault

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

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

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

@@ -1,53 +1,29 @@
 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.crypto.SecretKey;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 
-import javax.annotation.Nullable;
-import javax.annotation.concurrent.Immutable;
-
-import static org.briarproject.bramble.api.nullsafety.NullSafety.requireExactlyOneNull;
-
-@Immutable
-@NotNullByDefault
 public class StreamContext {
 
-	@Nullable
 	private final ContactId contactId;
-	@Nullable
-	private final PendingContactId pendingContactId;
 	private final TransportId transportId;
 	private final SecretKey tagKey, headerKey;
 	private final long streamNumber;
-	private final boolean handshakeMode;
 
-	public StreamContext(@Nullable ContactId contactId,
+	public StreamContext(ContactId contactId, TransportId transportId,
-			@Nullable PendingContactId pendingContactId,
+			SecretKey tagKey, SecretKey headerKey, long streamNumber) {
-			TransportId transportId, SecretKey tagKey, SecretKey headerKey,
-			long streamNumber, boolean handshakeMode) {
-		requireExactlyOneNull(contactId, pendingContactId);
 		this.contactId = contactId;
-		this.pendingContactId = pendingContactId;
 		this.transportId = transportId;
 		this.tagKey = tagKey;
 		this.headerKey = headerKey;
 		this.streamNumber = streamNumber;
-		this.handshakeMode = handshakeMode;
 	}
 
-	@Nullable
 	public ContactId getContactId() {
 		return contactId;
 	}
 
-	@Nullable
-	public PendingContactId getPendingContactId() {
-		return pendingContactId;
-	}
-
 	public TransportId getTransportId() {
 		return transportId;
 	}
@@ -63,8 +39,4 @@ public class StreamContext {
 	public long getStreamNumber() {
 		return streamNumber;
 	}
-
-	public boolean isHandshakeMode() {
-		return handshakeMode;
-	}
 }

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

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

@@ -1,64 +0,0 @@
-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;
-
-import static org.briarproject.bramble.api.nullsafety.NullSafety.requireExactlyOneNull;
-
-/**
- * A set of keys for communicating with a given contact or pending contact
- * over a given transport.
- */
-@Immutable
-@NotNullByDefault
-public class TransportKeySet {
-
-	private final KeySetId keySetId;
-	@Nullable
-	private final ContactId contactId;
-	@Nullable
-	private final PendingContactId pendingContactId;
-	private final TransportKeys keys;
-
-	public TransportKeySet(KeySetId keySetId, @Nullable ContactId contactId,
-			@Nullable PendingContactId pendingContactId, TransportKeys keys) {
-		requireExactlyOneNull(contactId, pendingContactId);
-		this.keySetId = keySetId;
-		this.contactId = contactId;
-		this.pendingContactId = pendingContactId;
-		this.keys = keys;
-	}
-
-	public KeySetId getKeySetId() {
-		return keySetId;
-	}
-
-	@Nullable
-	public ContactId getContactId() {
-		return contactId;
-	}
-
-	@Nullable
-	public PendingContactId getPendingContactId() {
-		return pendingContactId;
-	}
-
-	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/TransportKeys.java

@@ -1,54 +1,29 @@
 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.Nullable;
-import javax.annotation.concurrent.Immutable;
-
 /**
- * Keys for communicating with a given contact or pending contact over a given
+ * Keys for communicating with a given contact over a given transport.
- * transport.
  */
-@Immutable
-@NotNullByDefault
 public class TransportKeys {
 
 	private final TransportId transportId;
 	private final IncomingKeys inPrev, inCurr, inNext;
 	private final OutgoingKeys outCurr;
-	@Nullable
-	private final SecretKey rootKey;
-	private final boolean alice;
 
-	/**
-	 * Constructor for rotation mode.
-	 */
 	public TransportKeys(TransportId transportId, IncomingKeys inPrev,
 			IncomingKeys inCurr, IncomingKeys inNext, OutgoingKeys outCurr) {
-		this(transportId, inPrev, inCurr, inNext, outCurr, null, false);
+		if (inPrev.getRotationPeriod() != inCurr.getRotationPeriod() - 1)
-	}
-
-	/**
-	 * Constructor for handshake mode.
-	 */
-	public TransportKeys(TransportId transportId, IncomingKeys inPrev,
-			IncomingKeys inCurr, IncomingKeys inNext, OutgoingKeys outCurr,
-			@Nullable SecretKey rootKey, boolean alice) {
-		if (inPrev.getTimePeriod() != outCurr.getTimePeriod() - 1)
 			throw new IllegalArgumentException();
-		if (inCurr.getTimePeriod() != outCurr.getTimePeriod())
+		if (inNext.getRotationPeriod() != inCurr.getRotationPeriod() + 1)
 			throw new IllegalArgumentException();
-		if (inNext.getTimePeriod() != outCurr.getTimePeriod() + 1)
+		if (outCurr.getRotationPeriod() != inCurr.getRotationPeriod())
 			throw new IllegalArgumentException();
 		this.transportId = transportId;
 		this.inPrev = inPrev;
 		this.inCurr = inCurr;
 		this.inNext = inNext;
 		this.outCurr = outCurr;
-		this.rootKey = rootKey;
-		this.alice = alice;
 	}
 
 	public TransportId getTransportId() {
@@ -71,38 +46,7 @@ public class TransportKeys {
 		return outCurr;
 	}
 
-	public long getTimePeriod() {
+	public long getRotationPeriod() {
-		return outCurr.getTimePeriod();
+		return outCurr.getRotationPeriod();
-	}
-
-	/**
-	 * Returns true if these keys are for use in handshake mode or false if
-	 * they're for use in rotation mode.
-	 */
-	public boolean isHandshakeMode() {
-		return rootKey != null;
-	}
-
-	/**
-	 * If these keys are for use in handshake mode, returns the root key.
-	 *
-	 * @throws UnsupportedOperationException If these keys are for use in
-	 * rotation mode
-	 */
-	public SecretKey getRootKey() {
-		if (rootKey == null) throw new UnsupportedOperationException();
-		return rootKey;
-	}
-
-	/**
-	 * If these keys are for use in handshake mode, returns true if the local
-	 * party is Alice.
-	 *
-	 * @throws UnsupportedOperationException If these keys are for use in
-	 * rotation mode
-	 */
-	public boolean isAlice() {
-		if (rootKey == null) throw new UnsupportedOperationException();
-		return alice;
 	}
 }

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

@@ -46,14 +46,7 @@ public interface ClientVersioningManager {
 			ClientId clientId, int majorVersion) throws DbException;
 
 	interface ClientVersioningHook {
-		/**
+
-		 * Called when the visibility of a client with respect to a contact is
-		 * changing.
-		 *
-		 * @param txn A read-write transaction
-		 * @param c The contact affected by the visibility change
-		 * @param v The new visibility of the client
-		 */
 		void onClientVisibilityChanging(Transaction txn, Contact c,
 				Visibility v) throws DbException;
 	}

bramble-api/src/main/java/org/briarproject/bramble/util/Base32.java

@@ -1,75 +0,0 @@
-package org.briarproject.bramble.util;
-
-import java.io.ByteArrayOutputStream;
-
-public class Base32 {
-
-	private static final char[] DIGITS = {
-			'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L',
-			'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
-			'Y', 'Z', '2', '3', '4', '5', '6', '7'
-	};
-
-	public static String encode(byte[] b) {
-		StringBuilder s = new StringBuilder();
-		int byteIndex = 0, currentCode = 0x00;
-		int byteMask = 0x80, codeMask = 0x10;
-		while (byteIndex < b.length) {
-			if ((b[byteIndex] & byteMask) != 0) currentCode |= codeMask;
-			// After every 8 bits, move on to the next byte
-			if (byteMask == 0x01) {
-				byteMask = 0x80;
-				byteIndex++;
-			} else {
-				byteMask >>>= 1;
-			}
-			// After every 5 bits, move on to the next digit
-			if (codeMask == 0x01) {
-				s.append(DIGITS[currentCode]);
-				codeMask = 0x10;
-				currentCode = 0x00;
-			} else {
-				codeMask >>>= 1;
-			}
-		}
-		// If we're part-way through a digit, output it
-		if (codeMask != 0x10) s.append(DIGITS[currentCode]);
-		return s.toString();
-	}
-
-	public static byte[] decode(String s, boolean strict) {
-		ByteArrayOutputStream b = new ByteArrayOutputStream();
-		int digitIndex = 0, digitCount = s.length(), currentByte = 0x00;
-		int byteMask = 0x80, codeMask = 0x10;
-		while (digitIndex < digitCount) {
-			int code = decodeDigit(s.charAt(digitIndex));
-			if ((code & codeMask) != 0) currentByte |= byteMask;
-			// After every 8 bits, move on to the next byte
-			if (byteMask == 0x01) {
-				b.write(currentByte);
-				byteMask = 0x80;
-				currentByte = 0x00;
-			} else {
-				byteMask >>>= 1;
-			}
-			// After every 5 bits, move on to the next digit
-			if (codeMask == 0x01) {
-				codeMask = 0x10;
-				digitIndex++;
-			} else {
-				codeMask >>>= 1;
-			}
-		}
-		// If any extra bits were used for encoding, they should all be zero
-		if (strict && byteMask != 0x80 && currentByte != 0x00)
-			throw new IllegalArgumentException();
-		return b.toByteArray();
-	}
-
-	private static int decodeDigit(char c) {
-		if (c >= 'A' && c <= 'Z') return c - 'A';
-		if (c >= 'a' && c <= 'z') return c - 'a';
-		if (c >= '2' && c <= '7') return c - '2' + 26;
-		throw new IllegalArgumentException("Not a base32 digit: " + c);
-	}
-}

bramble-api/src/main/java/org/briarproject/bramble/util/LogUtils.java

@@ -1,6 +1,5 @@
 package org.briarproject.bramble.util;
 
-import java.io.File;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -20,7 +19,6 @@ public class LogUtils {
 
 	/**
 	 * Logs the duration of a task.
-	 *
 	 * @param logger the logger to use
 	 * @param task a description of the task
 	 * @param start the start time of the task, as returned by {@link #now()}
@@ -35,26 +33,4 @@ public class LogUtils {
 	public static void logException(Logger logger, Level level, Throwable t) {
 		if (logger.isLoggable(level)) logger.log(level, t.toString(), t);
 	}
-
-	public static void logFileOrDir(Logger logger, Level level, File f) {
-		if (logger.isLoggable(level)) {
-			if (f.isFile()) {
-				logWithType(logger, level, f, "F");
-			} else if (f.isDirectory()) {
-				logWithType(logger, level, f, "D");
-				File[] children = f.listFiles();
-				if (children != null) {
-					for (File child : children)
-						logFileOrDir(logger, level, child);
-				}
-			} else if (f.exists()) {
-				logWithType(logger, level, f, "?");
-			}
-		}
-	}
-
-	private static void logWithType(Logger logger, Level level, File f,
-			String type) {
-		logger.log(level, type + " " + f.getAbsolutePath() + " " + f.length());
-	}
 }

bramble-api/src/main/java/org/briarproject/bramble/util/StringUtils.java

@@ -153,13 +153,4 @@ public class StringUtils {
 		return new String(c);
 	}
 
-	public static String getRandomBase32String(int length) {
-		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);
-	}
 }

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

@@ -1,21 +1,9 @@
 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.contact.PendingContactState;
-import org.briarproject.bramble.api.crypto.AgreementPrivateKey;
-import org.briarproject.bramble.api.crypto.AgreementPublicKey;
-import org.briarproject.bramble.api.crypto.PrivateKey;
-import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.crypto.SecretKey;
-import org.briarproject.bramble.api.crypto.SignaturePrivateKey;
-import org.briarproject.bramble.api.crypto.SignaturePublicKey;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
-import org.briarproject.bramble.api.identity.Identity;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.properties.TransportProperties;
@@ -37,10 +25,9 @@ import java.util.Random;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import static java.util.Arrays.asList;
-import static org.briarproject.bramble.api.crypto.CryptoConstants.MAX_AGREEMENT_PUBLIC_KEY_BYTES;
-import static org.briarproject.bramble.api.crypto.CryptoConstants.MAX_SIGNATURE_PUBLIC_KEY_BYTES;
 import static org.briarproject.bramble.api.identity.Author.FORMAT_VERSION;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
 import static org.briarproject.bramble.api.plugin.TransportId.MAX_TRANSPORT_ID_LENGTH;
 import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MAX_PROPERTY_LENGTH;
 import static org.briarproject.bramble.api.sync.ClientId.MAX_CLIENT_ID_LENGTH;
@@ -54,7 +41,6 @@ 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();
@@ -107,46 +93,27 @@ public class TestUtils {
 		return new SecretKey(getRandomBytes(SecretKey.LENGTH));
 	}
 
-	public static PublicKey getSignaturePublicKey() {
+	public static LocalAuthor getLocalAuthor() {
-		byte[] key = getRandomBytes(MAX_SIGNATURE_PUBLIC_KEY_BYTES);
+		return getLocalAuthor(1 + random.nextInt(MAX_AUTHOR_NAME_LENGTH));
-		return new SignaturePublicKey(key);
 	}
 
-	public static PrivateKey getSignaturePrivateKey() {
+	public static LocalAuthor getLocalAuthor(int nameLength) {
-		return new SignaturePrivateKey(getRandomBytes(123));
+		AuthorId id = new AuthorId(getRandomId());
-	}
+		String name = getRandomString(nameLength);
-
+		byte[] publicKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
-	public static PublicKey getAgreementPublicKey() {
+		byte[] privateKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
-		byte[] key = getRandomBytes(MAX_AGREEMENT_PUBLIC_KEY_BYTES);
+		return new LocalAuthor(id, FORMAT_VERSION, name, publicKey, privateKey,
-		return new AgreementPublicKey(key);
-	}
-
-	public static PrivateKey getAgreementPrivateKey() {
-		return new AgreementPrivateKey(getRandomBytes(123));
-	}
-
-	public static Identity getIdentity() {
-		LocalAuthor localAuthor = getLocalAuthor();
-		PublicKey handshakePub = getAgreementPublicKey();
-		PrivateKey handshakePriv = getAgreementPrivateKey();
-		return new Identity(localAuthor, handshakePub, handshakePriv,
 				timestamp);
 	}
 
-	public static LocalAuthor getLocalAuthor() {
+	public static Author getAuthor() {
-		AuthorId id = new AuthorId(getRandomId());
+		return getAuthor(1 + random.nextInt(MAX_AUTHOR_NAME_LENGTH));
-		int nameLength = 1 + random.nextInt(MAX_AUTHOR_NAME_LENGTH);
-		String name = getRandomString(nameLength);
-		PublicKey publicKey = getSignaturePublicKey();
-		PrivateKey privateKey = getSignaturePrivateKey();
-		return new LocalAuthor(id, FORMAT_VERSION, name, publicKey, privateKey);
 	}
 
-	public static Author getAuthor() {
+	public static Author getAuthor(int nameLength) {
 		AuthorId id = new AuthorId(getRandomId());
-		int nameLength = 1 + random.nextInt(MAX_AUTHOR_NAME_LENGTH);
 		String name = getRandomString(nameLength);
-		PublicKey publicKey = getSignaturePublicKey();
+		byte[] publicKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
 		return new Author(id, FORMAT_VERSION, name, publicKey);
 	}
 
@@ -173,41 +140,6 @@ 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());
-		PublicKey publicKey = getAgreementPublicKey();
-		String alias = getRandomString(nameLength);
-		int stateIndex =
-				random.nextInt(PendingContactState.values().length - 1);
-		PendingContactState state = PendingContactState.values()[stateIndex];
-		return new PendingContact(id, publicKey, alias, state, timestamp);
-	}
-
-	public static ContactId getContactId() {
-		return new ContactId(nextContactId.getAndIncrement());
-	}
-
-	public static Contact getContact() {
-		return getContact(getAuthor(), new AuthorId(getRandomId()),
-				random.nextBoolean());
-	}
-
-	public static Contact getContact(Author remote, AuthorId local,
-			boolean verified) {
-		return getContact(getContactId(), remote, local, verified);
-	}
-
-	public static Contact getContact(ContactId c, Author remote, AuthorId local,
-			boolean verified) {
-		return new Contact(c, remote, local,
-				getRandomString(MAX_AUTHOR_NAME_LENGTH),
-				getAgreementPublicKey(), verified);
-	}
-
 	public static double getMedian(Collection<? extends Number> samples) {
 		int size = samples.size();
 		if (size == 0) throw new IllegalArgumentException();

bramble-api/witness.gradle

@@ -2,7 +2,7 @@ dependencyVerification {
     verify = [
         'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
         'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
-        'com.google.dagger:dagger:2.22.1:dagger-2.22.1.jar:329d4340f24c4f5717af016c097e90668bfea2a5376e6aa9964b01cef3fd241a',
+        'com.google.dagger:dagger:2.19:dagger-2.19.jar:514b6f1e0727c6572e1d65cb27e4ae668b7aeaeb93a29515182965265b609939',
         'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
         'junit:junit:4.12:junit-4.12.jar:59721f0805e223d84b90677887d9ff567dc534d7c502ca903c0c2b17f05c116a',
         'org.apache.ant:ant-launcher:1.9.4:ant-launcher-1.9.4.jar:7bccea20b41801ca17bcbc909a78c835d0f443f12d639c77bd6ae3d05861608d',

bramble-core/build.gradle

@@ -17,7 +17,7 @@ dependencies {
 	implementation 'org.whispersystems:curve25519-java:0.5.0'
 	implementation 'org.briarproject:jtorctl:0.3'
 
-	annotationProcessor 'com.google.dagger:dagger-compiler:2.22.1'
+	annotationProcessor 'com.google.dagger:dagger-compiler:2.19'
 
 	testImplementation project(path: ':bramble-api', configuration: 'testOutput')
 	testImplementation 'org.hsqldb:hsqldb:2.3.5' // The last version that supports Java 1.6
@@ -26,7 +26,7 @@ dependencies {
 	testImplementation "org.jmock:jmock-junit4:2.8.2"
 	testImplementation "org.jmock:jmock-legacy:2.8.2"
 
-	testAnnotationProcessor 'com.google.dagger:dagger-compiler:2.22.1'
+	testAnnotationProcessor 'com.google.dagger:dagger-compiler:2.19'
 
 	signature 'org.codehaus.mojo.signature:java16:1.1@signature'
 }

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

@@ -0,0 +1,67 @@
+package org.briarproject.bramble;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.util.LinkedList;
+import java.util.Queue;
+import java.util.concurrent.Executor;
+
+import javax.annotation.concurrent.GuardedBy;
+
+@NotNullByDefault
+public class PriorityExecutor {
+
+	private final Object lock = new Object();
+	private final Executor delegate, high, low;
+	@GuardedBy("lock")
+	private final Queue<Runnable> highQueue = new LinkedList<>();
+	@GuardedBy("lock")
+	private final Queue<Runnable> lowQueue = new LinkedList<>();
+
+	@GuardedBy("lock")
+	private boolean isTaskRunning = false;
+
+	public PriorityExecutor(Executor delegate) {
+		this.delegate = delegate;
+		high = r -> submit(r, true);
+		low = r -> submit(r, false);
+	}
+
+	public Executor getHighPriorityExecutor() {
+		return high;
+	}
+
+	public Executor getLowPriorityExecutor() {
+		return low;
+	}
+
+	private void submit(Runnable r, boolean isHighPriority) {
+		Runnable wrapped = () -> {
+			try {
+				r.run();
+			} finally {
+				scheduleNext();
+			}
+		};
+		synchronized (lock) {
+			if (!isTaskRunning && highQueue.isEmpty() &&
+					(isHighPriority || lowQueue.isEmpty())) {
+				isTaskRunning = true;
+				delegate.execute(wrapped);
+			} else if (isHighPriority) {
+				highQueue.add(wrapped);
+			} else {
+				lowQueue.add(wrapped);
+			}
+		}
+	}
+
+	private void scheduleNext() {
+		synchronized (lock) {
+			Runnable next = highQueue.poll();
+			if (next == null) next = lowQueue.poll();
+			if (next == null) isTaskRunning = false;
+			else delegate.execute(next);
+		}
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/account/AccountManagerImpl.java

@@ -4,8 +4,8 @@ import org.briarproject.bramble.api.account.AccountManager;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.DatabaseConfig;
-import org.briarproject.bramble.api.identity.Identity;
 import org.briarproject.bramble.api.identity.IdentityManager;
+import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.util.IoUtils;
@@ -161,8 +161,8 @@ class AccountManagerImpl implements AccountManager {
 		synchronized (stateChangeLock) {
 			if (hasDatabaseKey())
 				throw new AssertionError("Already have a database key");
-			Identity identity = identityManager.createIdentity(name);
+			LocalAuthor localAuthor = identityManager.createLocalAuthor(name);
-			identityManager.registerIdentity(identity);
+			identityManager.registerLocalAuthor(localAuthor);
 			SecretKey key = crypto.generateSecretKey();
 			if (!encryptAndStoreDatabaseKey(key, password)) return false;
 			databaseKey = key;

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

@@ -3,9 +3,6 @@ package org.briarproject.bramble.client;
 import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.api.client.ClientHelper;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
-import org.briarproject.bramble.api.crypto.KeyParser;
-import org.briarproject.bramble.api.crypto.PrivateKey;
-import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.data.BdfDictionary;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.data.BdfReader;
@@ -308,15 +305,14 @@ class ClientHelperImpl implements ClientHelper {
 	}
 
 	@Override
-	public byte[] sign(String label, BdfList toSign, PrivateKey privateKey)
+	public byte[] sign(String label, BdfList toSign, byte[] privateKey)
 			throws FormatException, GeneralSecurityException {
 		return crypto.sign(label, toByteArray(toSign), privateKey);
 	}
 
 	@Override
 	public void verifySignature(byte[] signature, String label, BdfList signed,
-			PublicKey publicKey)
+			byte[] publicKey) throws FormatException, GeneralSecurityException {
-			throws FormatException, GeneralSecurityException {
 		if (!crypto.verifySignature(signature, label, toByteArray(signed),
 				publicKey)) {
 			throw new GeneralSecurityException("Invalid signature");
@@ -331,29 +327,11 @@ class ClientHelperImpl implements ClientHelper {
 		if (formatVersion != FORMAT_VERSION) throw new FormatException();
 		String name = author.getString(1);
 		checkLength(name, 1, MAX_AUTHOR_NAME_LENGTH);
-		byte[] publicKeyBytes = author.getRaw(2);
+		byte[] publicKey = author.getRaw(2);
-		checkLength(publicKeyBytes, 1, MAX_PUBLIC_KEY_LENGTH);
+		checkLength(publicKey, 1, MAX_PUBLIC_KEY_LENGTH);
-		KeyParser parser = crypto.getSignatureKeyParser();
-		PublicKey publicKey;
-		try {
-			publicKey = parser.parsePublicKey(publicKeyBytes);
-		} catch (GeneralSecurityException e) {
-			throw new FormatException();
-		}
 		return authorFactory.createAuthor(formatVersion, name, publicKey);
 	}
 
-	@Override
-	public PublicKey parseAndValidateAgreementPublicKey(byte[] publicKeyBytes)
-			throws FormatException {
-		KeyParser parser = crypto.getAgreementKeyParser();
-		try {
-			return parser.parsePublicKey(publicKeyBytes);
-		} catch (GeneralSecurityException e) {
-			throw new FormatException();
-		}
-	}
-
 	@Override
 	public TransportProperties parseAndValidateTransportProperties(
 			BdfDictionary properties) throws FormatException {

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

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

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

@@ -1,6 +1,5 @@
 package org.briarproject.bramble.contact;
 
-import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
@@ -19,44 +18,47 @@ 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 org.briarproject.bramble.api.contact.HandshakeLinkConstants.BASE32_LINK_BYTES;
+import static java.util.Collections.emptyList;
+import static org.briarproject.bramble.api.contact.PendingContact.PendingContactState.WAITING_FOR_CONNECTION;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_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;
 import static org.briarproject.bramble.api.identity.AuthorInfo.Status.VERIFIED;
-import static org.briarproject.bramble.util.StringUtils.getRandomBase32String;
 import static org.briarproject.bramble.util.StringUtils.toUtf8;
 
 @ThreadSafe
 @NotNullByDefault
 class ContactManagerImpl implements ContactManager {
 
+	private static final int LINK_LENGTH = 64;
 	private static final String REMOTE_CONTACT_LINK =
-			"briar://" + getRandomBase32String(BASE32_LINK_BYTES);
+			"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;
-	private final PendingContactFactory pendingContactFactory;
 	private final List<ContactHook> hooks;
 
 	@Inject
 	ContactManagerImpl(DatabaseComponent db, KeyManager keyManager,
-			IdentityManager identityManager,
+			IdentityManager identityManager) {
-			PendingContactFactory pendingContactFactory) {
 		this.db = db;
 		this.keyManager = keyManager;
 		this.identityManager = identityManager;
-		this.pendingContactFactory = pendingContactFactory;
 		hooks = new CopyOnWriteArrayList<>();
 	}
 
@@ -67,11 +69,10 @@ class ContactManagerImpl implements ContactManager {
 
 	@Override
 	public ContactId addContact(Transaction txn, Author remote, AuthorId local,
-			SecretKey rootKey, long timestamp, boolean alice, boolean verified,
+			SecretKey master, long timestamp, boolean alice, boolean verified,
 			boolean active) throws DbException {
-		ContactId c = db.addContact(txn, remote, local, verified);
+		ContactId c = db.addContact(txn, remote, local, verified, active);
-		keyManager.addContactWithRotationKeys(txn, c, rootKey, timestamp,
+		keyManager.addContact(txn, c, master, timestamp, alice, active);
-				alice, active);
 		Contact contact = db.getContact(txn, c);
 		for (ContactHook hook : hooks) hook.addingContact(txn, contact);
 		return c;
@@ -79,45 +80,62 @@ class ContactManagerImpl implements ContactManager {
 
 	@Override
 	public ContactId addContact(Transaction txn, Author remote, AuthorId local,
-			boolean verified) throws DbException {
+			boolean verified, boolean active) throws DbException {
-		ContactId c = db.addContact(txn, remote, local, verified);
+		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,
+	public ContactId addContact(Author remote, AuthorId local, SecretKey master,
-			SecretKey rootKey, long timestamp, boolean alice, boolean verified,
+			long timestamp, boolean alice, boolean verified, boolean active)
-			boolean active) throws DbException {
+			throws DbException {
 		return db.transactionWithResult(false, txn ->
-				addContact(txn, remote, local, rootKey, timestamp, alice,
+				addContact(txn, remote, local, master, timestamp, alice,
 						verified, active));
 	}
 
 	@Override
-	public String getHandshakeLink() {
+	public String getRemoteContactLink() {
 		// TODO replace with real implementation
 		return REMOTE_CONTACT_LINK;
 	}
 
-	@Override
+	@SuppressWarnings("SameParameterValue")
-	public PendingContact addPendingContact(String link, String alias)
+	private static String getRandomBase32String(int length) {
-			throws DbException, FormatException {
+		Random random = new Random();
-		PendingContact p =
+		char[] c = new char[length];
-				pendingContactFactory.createPendingContact(link, alias);
+		for (int i = 0; i < length; i++) {
-		db.transaction(false, txn -> db.addPendingContact(txn, p));
+			int character = random.nextInt(32);
-		return p;
+			if (character < 26) c[i] = (char) ('a' + character);
+			else c[i] = (char) ('2' + (character - 26));
+		}
+		return new String(c);
 	}
 
 	@Override
-	public Collection<PendingContact> getPendingContacts() throws DbException {
+	public boolean isValidRemoteContactLink(String link) {
-		return db.transactionWithResult(true, db::getPendingContacts);
+		return LINK_REGEX.matcher(link).matches();
 	}
 
 	@Override
-	public void removePendingContact(PendingContactId p) throws DbException {
+	public PendingContact addRemoteContactRequest(String link, String alias) {
-		db.transaction(false, txn -> db.removePendingContact(txn, p));
+		// TODO replace with real implementation
+		PendingContactId id = new PendingContactId(link.getBytes());
+		return new PendingContact(id, 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
@@ -146,8 +164,12 @@ class ContactManagerImpl implements ContactManager {
 	}
 
 	@Override
-	public Collection<Contact> getContacts() throws DbException {
+	public Collection<Contact> getActiveContacts() throws DbException {
-		return db.transactionWithResult(true, db::getContacts);
+		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;
 	}
 
 	@Override
@@ -155,6 +177,12 @@ 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 {

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

@@ -28,10 +28,4 @@ public class ContactModule {
 			ContactExchangeTaskImpl contactExchangeTask) {
 		return contactExchangeTask;
 	}
-
-	@Provides
-	PendingContactFactory providePendingContactFactory(
-			PendingContactFactoryImpl pendingContactFactory) {
-		return pendingContactFactory;
-	}
 }

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

@@ -1,18 +0,0 @@
-package org.briarproject.bramble.contact;
-
-import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.UnsupportedVersionException;
-import org.briarproject.bramble.api.contact.PendingContact;
-
-interface PendingContactFactory {
-
-	/**
-	 * Creates a {@link PendingContact} from the given handshake link and alias.
-	 *
-	 * @throws UnsupportedVersionException If the link uses a format version
-	 * that is not supported
-	 * @throws FormatException If the link is invalid
-	 */
-	PendingContact createPendingContact(String link, String alias)
-			throws FormatException;
-}

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

@@ -1,70 +0,0 @@
-package org.briarproject.bramble.contact;
-
-import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.UnsupportedVersionException;
-import org.briarproject.bramble.api.contact.PendingContact;
-import org.briarproject.bramble.api.contact.PendingContactId;
-import org.briarproject.bramble.api.crypto.CryptoComponent;
-import org.briarproject.bramble.api.crypto.KeyParser;
-import org.briarproject.bramble.api.crypto.PublicKey;
-import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.bramble.util.Base32;
-
-import java.security.GeneralSecurityException;
-import java.util.regex.Matcher;
-
-import javax.inject.Inject;
-
-import static java.lang.System.arraycopy;
-import static org.briarproject.bramble.api.contact.HandshakeLinkConstants.FORMAT_VERSION;
-import static org.briarproject.bramble.api.contact.HandshakeLinkConstants.ID_LABEL;
-import static org.briarproject.bramble.api.contact.HandshakeLinkConstants.LINK_REGEX;
-import static org.briarproject.bramble.api.contact.HandshakeLinkConstants.RAW_LINK_BYTES;
-import static org.briarproject.bramble.api.contact.PendingContactState.WAITING_FOR_CONNECTION;
-
-class PendingContactFactoryImpl implements PendingContactFactory {
-
-	private final CryptoComponent crypto;
-	private final Clock clock;
-
-	@Inject
-	PendingContactFactoryImpl(CryptoComponent crypto, Clock clock) {
-		this.crypto = crypto;
-		this.clock = clock;
-	}
-
-	@Override
-	public PendingContact createPendingContact(String link, String alias)
-			throws FormatException {
-		PublicKey publicKey = parseHandshakeLink(link);
-		PendingContactId id = getPendingContactId(publicKey);
-		long timestamp = clock.currentTimeMillis();
-		return new PendingContact(id, publicKey, alias, WAITING_FOR_CONNECTION,
-				timestamp);
-	}
-
-	private PublicKey parseHandshakeLink(String link) throws FormatException {
-		Matcher matcher = LINK_REGEX.matcher(link);
-		if (!matcher.find()) throw new FormatException();
-		// Discard 'briar://' and anything before or after the link
-		link = matcher.group(2);
-		byte[] base32 = Base32.decode(link, false);
-		if (base32.length != RAW_LINK_BYTES) throw new AssertionError();
-		byte version = base32[0];
-		if (version != FORMAT_VERSION)
-			throw new UnsupportedVersionException(version < FORMAT_VERSION);
-		byte[] publicKeyBytes = new byte[base32.length - 1];
-		arraycopy(base32, 1, publicKeyBytes, 0, publicKeyBytes.length);
-		try {
-			KeyParser parser = crypto.getAgreementKeyParser();
-			return parser.parsePublicKey(publicKeyBytes);
-		} catch (GeneralSecurityException e) {
-			throw new FormatException();
-		}
-	}
-
-	private PendingContactId getPendingContactId(PublicKey publicKey) {
-		byte[] hash = crypto.hash(ID_LABEL, publicKey.getEncoded());
-		return new PendingContactId(hash);
-	}
-}

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

@@ -4,16 +4,12 @@ import net.i2p.crypto.eddsa.EdDSAPrivateKey;
 import net.i2p.crypto.eddsa.EdDSAPublicKey;
 import net.i2p.crypto.eddsa.KeyPairGenerator;
 
-import org.briarproject.bramble.api.crypto.AgreementPrivateKey;
-import org.briarproject.bramble.api.crypto.AgreementPublicKey;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.KeyPair;
 import org.briarproject.bramble.api.crypto.KeyParser;
 import org.briarproject.bramble.api.crypto.PrivateKey;
 import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.crypto.SecretKey;
-import org.briarproject.bramble.api.crypto.SignaturePrivateKey;
-import org.briarproject.bramble.api.crypto.SignaturePublicKey;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.system.SecureRandomProvider;
 import org.briarproject.bramble.util.ByteUtils;
@@ -35,8 +31,6 @@ import javax.annotation.Nullable;
 import javax.inject.Inject;
 
 import static java.util.logging.Level.INFO;
-import static org.briarproject.bramble.api.crypto.CryptoConstants.KEY_TYPE_AGREEMENT;
-import static org.briarproject.bramble.api.crypto.CryptoConstants.KEY_TYPE_SIGNATURE;
 import static org.briarproject.bramble.util.ByteUtils.INT_32_BYTES;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.now;
@@ -86,8 +80,8 @@ class CryptoComponentImpl implements CryptoComponent {
 		signatureKeyPairGenerator = new KeyPairGenerator();
 		signatureKeyPairGenerator.initialize(SIGNATURE_KEY_PAIR_BITS,
 				secureRandom);
-		agreementKeyParser = new AgreementKeyParser();
+		agreementKeyParser = new Curve25519KeyParser();
-		signatureKeyParser = new SignatureKeyParser();
+		signatureKeyParser = new EdKeyParser();
 		messageEncrypter = new MessageEncrypter(secureRandom);
 	}
 
@@ -131,9 +125,9 @@ class CryptoComponentImpl implements CryptoComponent {
 	// Package access for testing
 	byte[] performRawKeyAgreement(PrivateKey priv, PublicKey pub)
 			throws GeneralSecurityException {
-		if (!priv.getKeyType().equals(KEY_TYPE_AGREEMENT))
+		if (!(priv instanceof Curve25519PrivateKey))
 			throw new IllegalArgumentException();
-		if (!pub.getKeyType().equals(KEY_TYPE_AGREEMENT))
+		if (!(pub instanceof Curve25519PublicKey))
 			throw new IllegalArgumentException();
 		long start = now();
 		byte[] secret = curve25519.calculateAgreement(pub.getEncoded(),
@@ -149,8 +143,8 @@ class CryptoComponentImpl implements CryptoComponent {
 	@Override
 	public KeyPair generateAgreementKeyPair() {
 		Curve25519KeyPair keyPair = curve25519.generateKeyPair();
-		PublicKey pub = new AgreementPublicKey(keyPair.getPublicKey());
+		PublicKey pub = new Curve25519PublicKey(keyPair.getPublicKey());
-		PrivateKey priv = new AgreementPrivateKey(keyPair.getPrivateKey());
+		PrivateKey priv = new Curve25519PrivateKey(keyPair.getPrivateKey());
 		return new KeyPair(pub, priv);
 	}
 
@@ -164,9 +158,9 @@ class CryptoComponentImpl implements CryptoComponent {
 		java.security.KeyPair keyPair =
 				signatureKeyPairGenerator.generateKeyPair();
 		EdDSAPublicKey edPublicKey = (EdDSAPublicKey) keyPair.getPublic();
-		PublicKey publicKey = new SignaturePublicKey(edPublicKey.getAbyte());
+		PublicKey publicKey = new EdPublicKey(edPublicKey.getAbyte());
 		EdDSAPrivateKey edPrivateKey = (EdDSAPrivateKey) keyPair.getPrivate();
-		PrivateKey privateKey = new SignaturePrivateKey(edPrivateKey.getSeed());
+		PrivateKey privateKey = new EdPrivateKey(edPrivateKey.getSeed());
 		return new KeyPair(publicKey, privateKey);
 	}
 
@@ -201,22 +195,21 @@ class CryptoComponentImpl implements CryptoComponent {
 	}
 
 	@Override
-	public byte[] sign(String label, byte[] toSign, PrivateKey privateKey)
+	public byte[] sign(String label, byte[] toSign, byte[] privateKey)
 			throws GeneralSecurityException {
+		PrivateKey key = signatureKeyParser.parsePrivateKey(privateKey);
 		Signature sig = new EdSignature();
-		sig.initSign(privateKey);
+		sig.initSign(key);
 		updateSignature(sig, label, toSign);
 		return sig.sign();
 	}
 
 	@Override
 	public boolean verifySignature(byte[] signature, String label,
-			byte[] signed, PublicKey publicKey)
+			byte[] signed, byte[] publicKey) throws GeneralSecurityException {
-			throws GeneralSecurityException {
+		PublicKey key = signatureKeyParser.parsePublicKey(publicKey);
-		if (!publicKey.getKeyType().equals(KEY_TYPE_SIGNATURE))
-			throw new IllegalArgumentException();
 		Signature sig = new EdSignature();
-		sig.initVerify(publicKey);
+		sig.initVerify(key);
 		updateSignature(sig, label, signed);
 		return sig.verify(signature);
 	}

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

@@ -1,7 +1,5 @@
 package org.briarproject.bramble.crypto;
 
-import org.briarproject.bramble.api.crypto.AgreementPrivateKey;
-import org.briarproject.bramble.api.crypto.AgreementPublicKey;
 import org.briarproject.bramble.api.crypto.KeyParser;
 import org.briarproject.bramble.api.crypto.PrivateKey;
 import org.briarproject.bramble.api.crypto.PublicKey;
@@ -9,24 +7,21 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.security.GeneralSecurityException;
 
-import javax.annotation.concurrent.Immutable;
-
-@Immutable
 @NotNullByDefault
-class AgreementKeyParser implements KeyParser {
+class Curve25519KeyParser implements KeyParser {
 
 	@Override
 	public PublicKey parsePublicKey(byte[] encodedKey)
 			throws GeneralSecurityException {
 		if (encodedKey.length != 32) throw new GeneralSecurityException();
-		return new AgreementPublicKey(encodedKey);
+		return new Curve25519PublicKey(encodedKey);
 	}
 
 	@Override
 	public PrivateKey parsePrivateKey(byte[] encodedKey)
 			throws GeneralSecurityException {
 		if (encodedKey.length != 32) throw new GeneralSecurityException();
-		return new AgreementPrivateKey(clamp(encodedKey));
+		return new Curve25519PrivateKey(clamp(encodedKey));
 	}
 
 	static byte[] clamp(byte[] b) {

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

@@ -0,0 +1,18 @@
+package org.briarproject.bramble.crypto;
+
+import org.briarproject.bramble.api.Bytes;
+import org.briarproject.bramble.api.crypto.PrivateKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+class Curve25519PrivateKey extends Bytes implements PrivateKey {
+
+	Curve25519PrivateKey(byte[] bytes) {
+		super(bytes);
+	}
+
+	@Override
+	public byte[] getEncoded() {
+		return getBytes();
+	}
+}

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

@@ -0,0 +1,18 @@
+package org.briarproject.bramble.crypto;
+
+import org.briarproject.bramble.api.Bytes;
+import org.briarproject.bramble.api.crypto.PublicKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+class Curve25519PublicKey extends Bytes implements PublicKey {
+
+	Curve25519PublicKey(byte[] bytes) {
+		super(bytes);
+	}
+
+	@Override
+	public byte[] getEncoded() {
+		return getBytes();
+	}
+}

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

@@ -3,29 +3,24 @@ package org.briarproject.bramble.crypto;
 import org.briarproject.bramble.api.crypto.KeyParser;
 import org.briarproject.bramble.api.crypto.PrivateKey;
 import org.briarproject.bramble.api.crypto.PublicKey;
-import org.briarproject.bramble.api.crypto.SignaturePrivateKey;
-import org.briarproject.bramble.api.crypto.SignaturePublicKey;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.security.GeneralSecurityException;
 
-import javax.annotation.concurrent.Immutable;
-
-@Immutable
 @NotNullByDefault
-class SignatureKeyParser implements KeyParser {
+class EdKeyParser implements KeyParser {
 
 	@Override
 	public PublicKey parsePublicKey(byte[] encodedKey)
 			throws GeneralSecurityException {
 		if (encodedKey.length != 32) throw new GeneralSecurityException();
-		return new SignaturePublicKey(encodedKey);
+		return new EdPublicKey(encodedKey);
 	}
 
 	@Override
 	public PrivateKey parsePrivateKey(byte[] encodedKey)
 			throws GeneralSecurityException {
 		if (encodedKey.length != 32) throw new GeneralSecurityException();
-		return new SignaturePrivateKey(encodedKey);
+		return new EdPrivateKey(encodedKey);
 	}
 }

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

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

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

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

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

@@ -17,7 +17,6 @@ import java.security.NoSuchAlgorithmException;
 import java.security.Provider;
 
 import static net.i2p.crypto.eddsa.EdDSAEngine.SIGNATURE_ALGORITHM;
-import static org.briarproject.bramble.api.crypto.CryptoConstants.KEY_TYPE_SIGNATURE;
 
 @NotNullByDefault
 class EdSignature implements Signature {
@@ -40,7 +39,7 @@ class EdSignature implements Signature {
 
 	@Override
 	public void initSign(PrivateKey k) throws GeneralSecurityException {
-		if (!k.getKeyType().equals(KEY_TYPE_SIGNATURE))
+		if (!(k instanceof EdPrivateKey))
 			throw new IllegalArgumentException();
 		EdDSAPrivateKey privateKey = new EdDSAPrivateKey(
 				new EdDSAPrivateKeySpec(k.getEncoded(), CURVE_SPEC));
@@ -49,7 +48,7 @@ class EdSignature implements Signature {
 
 	@Override
 	public void initVerify(PublicKey k) throws GeneralSecurityException {
-		if (!k.getKeyType().equals(KEY_TYPE_SIGNATURE))
+		if (!(k instanceof EdPublicKey))
 			throw new IllegalArgumentException();
 		EdDSAPublicKey publicKey = new EdDSAPublicKey(
 				new EdDSAPublicKeySpec(k.getEncoded(), CURVE_SPEC));

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

@@ -49,7 +49,6 @@ import javax.annotation.concurrent.Immutable;
 @NotNullByDefault
 public class MessageEncrypter {
 
-	private static final String KEY_TYPE = "SEC1_brainpoolp512r1";
 	private static final ECDomainParameters PARAMETERS;
 	private static final int MESSAGE_KEY_BITS = 512;
 	private static final int MAC_KEY_BITS = 256;
@@ -70,7 +69,7 @@ public class MessageEncrypter {
 	MessageEncrypter(SecureRandom random) {
 		generator = new ECKeyPairGenerator();
 		generator.init(new ECKeyGenerationParameters(PARAMETERS, random));
-		parser = new Sec1KeyParser(KEY_TYPE, PARAMETERS, MESSAGE_KEY_BITS);
+		parser = new Sec1KeyParser(PARAMETERS, MESSAGE_KEY_BITS);
 		KeyEncoder encoder = new PublicKeyEncoder();
 		ephemeralGenerator = new EphemeralKeyPairGenerator(generator, encoder);
 		ephemeralParser = new PublicKeyParser(PARAMETERS);
@@ -81,11 +80,11 @@ public class MessageEncrypter {
 		// Return a wrapper that uses the SEC 1 encoding
 		ECPublicKeyParameters ecPublicKey =
 				(ECPublicKeyParameters) keyPair.getPublic();
-		PublicKey publicKey = new Sec1PublicKey(KEY_TYPE, ecPublicKey);
+		PublicKey publicKey = new Sec1PublicKey(ecPublicKey);
 		ECPrivateKeyParameters ecPrivateKey =
 				(ECPrivateKeyParameters) keyPair.getPrivate();
 		PrivateKey privateKey =
-				new Sec1PrivateKey(KEY_TYPE, ecPrivateKey, MESSAGE_KEY_BITS);
+				new Sec1PrivateKey(ecPrivateKey, MESSAGE_KEY_BITS);
 		return new KeyPair(publicKey, privateKey);
 	}
 

bramble-core/src/main/java/org/briarproject/bramble/crypto/Sec1KeyParser.java

@@ -31,13 +31,11 @@ class Sec1KeyParser implements KeyParser {
 	private static final Logger LOG =
 			Logger.getLogger(Sec1KeyParser.class.getName());
 
-	private final String keyType;
 	private final ECDomainParameters params;
 	private final BigInteger modulus;
 	private final int keyBits, bytesPerInt, publicKeyBytes, privateKeyBytes;
 
-	Sec1KeyParser(String keyType, ECDomainParameters params, int keyBits) {
+	Sec1KeyParser(ECDomainParameters params, int keyBits) {
-		this.keyType = keyType;
 		this.params = params;
 		this.keyBits = keyBits;
 		modulus = ((ECCurve.Fp) params.getCurve()).getQ();
@@ -82,7 +80,7 @@ class Sec1KeyParser implements KeyParser {
 			throw new GeneralSecurityException();
 		// Construct a public key from the point (x, y) and the params
 		ECPublicKeyParameters k = new ECPublicKeyParameters(pub, params);
-		PublicKey p = new Sec1PublicKey(keyType, k);
+		PublicKey p = new Sec1PublicKey(k);
 		logDuration(LOG, "Parsing public key", start);
 		return p;
 	}
@@ -99,7 +97,7 @@ class Sec1KeyParser implements KeyParser {
 			throw new GeneralSecurityException();
 		// Construct a private key from the private value and the params
 		ECPrivateKeyParameters k = new ECPrivateKeyParameters(d, params);
-		PrivateKey p = new Sec1PrivateKey(keyType, k, keyBits);
+		PrivateKey p = new Sec1PrivateKey(k, keyBits);
 		logDuration(LOG, "Parsing private key", start);
 		return p;
 	}

bramble-core/src/main/java/org/briarproject/bramble/crypto/Sec1PrivateKey.java

@@ -10,21 +10,14 @@ import javax.annotation.concurrent.Immutable;
 @NotNullByDefault
 class Sec1PrivateKey implements PrivateKey {
 
-	private final String keyType;
 	private final ECPrivateKeyParameters key;
 	private final int bytesPerInt;
 
-	Sec1PrivateKey(String keyType, ECPrivateKeyParameters key, int keyBits) {
+	Sec1PrivateKey(ECPrivateKeyParameters key, int keyBits) {
-		this.keyType = keyType;
 		this.key = key;
 		bytesPerInt = (keyBits + 7) / 8;
 	}
 
-	@Override
-	public String getKeyType() {
-		return keyType;
-	}
-
 	@Override
 	public byte[] getEncoded() {
 		byte[] encodedKey = new byte[bytesPerInt];

bramble-core/src/main/java/org/briarproject/bramble/crypto/Sec1PublicKey.java

@@ -15,19 +15,12 @@ import javax.annotation.concurrent.Immutable;
 @NotNullByDefault
 class Sec1PublicKey implements PublicKey {
 
-	private final String keyType;
 	private final ECPublicKeyParameters key;
 
-	Sec1PublicKey(String keyType, ECPublicKeyParameters key) {
+	Sec1PublicKey(ECPublicKeyParameters key) {
-		this.keyType = keyType;
 		this.key = key;
 	}
 
-	@Override
-	public String getKeyType() {
-		return keyType;
-	}
-
 	@Override
 	public byte[] getEncoded() {
 		return key.getQ().getEncoded(false);

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

@@ -7,18 +7,15 @@ import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.transport.IncomingKeys;
 import org.briarproject.bramble.api.transport.OutgoingKeys;
 import org.briarproject.bramble.api.transport.TransportKeys;
+import org.briarproject.bramble.util.ByteUtils;
+import org.briarproject.bramble.util.StringUtils;
 import org.spongycastle.crypto.Digest;
 import org.spongycastle.crypto.digests.Blake2bDigest;
 
 import javax.inject.Inject;
 
-import static 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;
@@ -27,9 +24,6 @@ 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 {
 
@@ -41,163 +35,46 @@ class TransportCryptoImpl implements TransportCrypto {
 	}
 
 	@Override
-	public TransportKeys deriveRotationKeys(TransportId t,
+	public TransportKeys deriveTransportKeys(TransportId t,
-			SecretKey rootKey, long timePeriod, boolean weAreAlice,
+			SecretKey master, long rotationPeriod, boolean alice,
 			boolean active) {
-		// Keys for the previous period are derived from the root key
+		// Keys for the previous period are derived from the master secret
-		SecretKey inTagPrev = deriveTagKey(rootKey, t, !weAreAlice);
+		SecretKey inTagPrev = deriveTagKey(master, t, !alice);
-		SecretKey inHeaderPrev = deriveHeaderKey(rootKey, t, !weAreAlice);
+		SecretKey inHeaderPrev = deriveHeaderKey(master, t, !alice);
-		SecretKey outTagPrev = deriveTagKey(rootKey, t, weAreAlice);
+		SecretKey outTagPrev = deriveTagKey(master, t, alice);
-		SecretKey outHeaderPrev = deriveHeaderKey(rootKey, t, weAreAlice);
+		SecretKey outHeaderPrev = deriveHeaderKey(master, t, alice);
 		// Derive the keys for the current and next periods
-		SecretKey inTagCurr = rotateKey(inTagPrev, timePeriod);
+		SecretKey inTagCurr = rotateKey(inTagPrev, rotationPeriod);
-		SecretKey inHeaderCurr = rotateKey(inHeaderPrev, timePeriod);
+		SecretKey inHeaderCurr = rotateKey(inHeaderPrev, rotationPeriod);
-		SecretKey inTagNext = rotateKey(inTagCurr, timePeriod + 1);
+		SecretKey inTagNext = rotateKey(inTagCurr, rotationPeriod + 1);
-		SecretKey inHeaderNext = rotateKey(inHeaderCurr, timePeriod + 1);
+		SecretKey inHeaderNext = rotateKey(inHeaderCurr, rotationPeriod + 1);
-		SecretKey outTagCurr = rotateKey(outTagPrev, timePeriod);
+		SecretKey outTagCurr = rotateKey(outTagPrev, rotationPeriod);
-		SecretKey outHeaderCurr = rotateKey(outHeaderPrev, timePeriod);
+		SecretKey outHeaderCurr = rotateKey(outHeaderPrev, rotationPeriod);
 		// Initialise the reordering windows and stream counters
 		IncomingKeys inPrev = new IncomingKeys(inTagPrev, inHeaderPrev,
-				timePeriod - 1);
+				rotationPeriod - 1);
 		IncomingKeys inCurr = new IncomingKeys(inTagCurr, inHeaderCurr,
-				timePeriod);
+				rotationPeriod);
 		IncomingKeys inNext = new IncomingKeys(inTagNext, inHeaderNext,
-				timePeriod + 1);
+				rotationPeriod + 1);
 		OutgoingKeys outCurr = new OutgoingKeys(outTagCurr, outHeaderCurr,
-				timePeriod, active);
+				rotationPeriod, active);
 		// Collect and return the keys
 		return new TransportKeys(t, inPrev, inCurr, inNext, outCurr);
 	}
 
-	private SecretKey rotateKey(SecretKey k, long timePeriod) {
-		byte[] period = new byte[INT_64_BYTES];
-		writeUint64(timePeriod, period, 0);
-		return crypto.deriveKey(ROTATE_LABEL, k, period);
-	}
-
-	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 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 TransportKeys deriveHandshakeKeys(TransportId t, SecretKey rootKey,
+	public TransportKeys rotateTransportKeys(TransportKeys k,
-			long timePeriod, boolean weAreAlice) {
+			long rotationPeriod) {
-		if (timePeriod < 1) throw new IllegalArgumentException();
+		if (k.getRotationPeriod() >= rotationPeriod) return k;
-		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 TransportKeys(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 TransportKeys updateTransportKeys(TransportKeys k, long timePeriod) {
-		if (k.isHandshakeMode()) return updateHandshakeKeys(k, timePeriod);
-		else return updateRotationKeys(k, timePeriod);
-	}
-
-	private TransportKeys updateHandshakeKeys(TransportKeys 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 TransportKeys(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 TransportKeys(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);
-		}
-	}
-
-	private TransportKeys updateRotationKeys(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.getTimePeriod();
+		long startPeriod = outCurr.getRotationPeriod();
 		boolean active = outCurr.isActive();
 		// Rotate the keys
-		for (long p = startPeriod + 1; p <= timePeriod; p++) {
+		for (long p = startPeriod + 1; p <= rotationPeriod; p++) {
 			inPrev = inCurr;
 			inCurr = inNext;
 			SecretKey inNextTag = rotateKey(inNext.getTagKey(), p + 1);
@@ -212,6 +89,26 @@ class TransportCryptoImpl implements TransportCrypto {
 				outCurr);
 	}
 
+	private SecretKey rotateKey(SecretKey k, long rotationPeriod) {
+		byte[] period = new byte[INT_64_BYTES];
+		ByteUtils.writeUint64(rotationPeriod, period, 0);
+		return crypto.deriveKey(ROTATE_LABEL, k, period);
+	}
+
+	private SecretKey deriveTagKey(SecretKey master, TransportId t,
+			boolean alice) {
+		String label = alice ? ALICE_TAG_LABEL : BOB_TAG_LABEL;
+		byte[] id = StringUtils.toUtf8(t.getString());
+		return crypto.deriveKey(label, master, id);
+	}
+
+	private SecretKey deriveHeaderKey(SecretKey master, TransportId t,
+			boolean alice) {
+		String label = alice ? ALICE_HEADER_LABEL : BOB_HEADER_LABEL;
+		byte[] id = StringUtils.toUtf8(t.getString());
+		return crypto.deriveKey(label, master, id);
+	}
+
 	@Override
 	public void encodeTag(byte[] tag, SecretKey tagKey, int protocolVersion,
 			long streamNumber) {
@@ -228,14 +125,14 @@ 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];
-		writeUint16(protocolVersion, protocolVersionBytes, 0);
+		ByteUtils.writeUint16(protocolVersion, protocolVersionBytes, 0);
 		prf.update(protocolVersionBytes, 0, protocolVersionBytes.length);
 		byte[] streamNumberBytes = new byte[INT_64_BYTES];
-		writeUint64(streamNumber, streamNumberBytes, 0);
+		ByteUtils.writeUint64(streamNumber, streamNumberBytes, 0);
 		prf.update(streamNumberBytes, 0, streamNumberBytes.length);
 		byte[] mac = new byte[macLength];
 		prf.doFinal(mac, 0);
 		// The output is the first TAG_LENGTH bytes of the MAC
-		arraycopy(mac, 0, tag, 0, TAG_LENGTH);
+		System.arraycopy(mac, 0, tag, 0, TAG_LENGTH);
 	}
 }