Bump version numbers for 1.1.7 release.

Adapt private group join notices to new threaded layout

Closes #1369

See merge request briar/briar!1097

.idea/codeStyles/Project.xml

@@ -39,31 +39,6 @@
     <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 10106
+		versionCode 10107
-		versionName "1.1.6"
+		versionName "1.1.7"
 		consumerProguardFiles 'proguard-rules.txt'
 
 		testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
@@ -33,7 +33,7 @@ dependencies {
 	tor 'org.briarproject:tor-android:0.3.5.8@zip'
 	tor 'org.briarproject:obfs4proxy-android:0.0.9@zip'
 
-	annotationProcessor 'com.google.dagger:dagger-compiler:2.19'
+	annotationProcessor 'com.google.dagger:dagger-compiler:2.22.1'
 
 	compileOnly 'javax.annotation:jsr250-api:1.0'
 

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

@@ -9,7 +9,6 @@ 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;
@@ -20,6 +19,9 @@ 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 {
@@ -41,6 +43,16 @@ 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
@@ -74,9 +86,17 @@ 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());
+			}
 		}
 	}
 
@@ -94,7 +114,7 @@ class AndroidAccountManager extends AccountManagerImpl
 		}
 		// Delete files, except lib and shared_prefs directories
 		Set<File> files = new HashSet<>();
-		File dataDir = new File(appContext.getApplicationInfo().dataDir);
+		File dataDir = getDataDir();
 		@Nullable
 		File[] fileArray = dataDir.listFiles();
 		if (fileArray == null) {
@@ -121,13 +141,17 @@ class AndroidAccountManager extends AccountManagerImpl
 			}
 		}
 		for (File file : files) {
-			IoUtils.deleteFileOrDir(file);
+			deleteFileOrDir(file);
 		}
 		// Recreate the cache dir as some OpenGL drivers expect it to exist
 		if (!new File(dataDir, "cache").mkdirs())
 			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/test/java/org/briarproject/bramble/account/AndroidAccountManagerTest.java

@@ -128,7 +128,7 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 			will(returnValue(editor));
 			oneOf(editor).commit();
 			will(returnValue(true));
-			oneOf(app).getApplicationInfo();
+			allowing(app).getApplicationInfo();
 			will(returnValue(applicationInfo));
 			oneOf(app).getFilesDir();
 			will(returnValue(filesDir));

bramble-android/witness.gradle

@@ -1,45 +1,45 @@
 dependencyVerification {
     verify = [
         'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
-        'com.android.tools.analytics-library:protos:26.3.2:protos-26.3.2.jar:50238fb4298b297217b184b9cd93c14f83536fcee829eb0ca850bdb5b53251f0',
+        'com.android.tools.analytics-library:protos:26.4.0:protos-26.4.0.jar:ad760915586797d39319f402837b378bff3bb4ed583e3e0c48c965631fb2135f',
-        'com.android.tools.analytics-library:shared:26.3.2:shared-26.3.2.jar:ddd80dcf21905018b7c0583ba72b7282f446084d4952422609a09fbf8237ef71',
+        'com.android.tools.analytics-library:shared:26.4.0:shared-26.4.0.jar:1332106a905d48909c81268c9e414946de3e83487db394c6073b0a9b5c3d0ed2',
-        'com.android.tools.analytics-library:tracker:26.3.2:tracker-26.3.2.jar:28c575d2d1af003e96d7b375a668ee10b2673a2dd0f6438750aa8c3b42e7d0ad',
+        'com.android.tools.analytics-library:tracker:26.4.0:tracker-26.4.0.jar:d0020cfbfd4cd75935f2972d6a24089840d4a10df6f3ef2a796093217dd37796',
-        'com.android.tools.build:apksig:3.3.2:apksig-3.3.2.jar:84c4aaa20127c6c1fe6bdd334b3f5df71f54ad080be9029c8a10f43b6a908acd',
+        'com.android.tools.build:apksig:3.4.0:apksig-3.4.0.jar:91d5a1866139c69756280355a6f61b4d619d0516841580114f45a10f2177327e',
-        'com.android.tools.build:apkzlib:3.3.2:apkzlib-3.3.2.jar:d34e523278e5dff565eba3ef3c089d515b2b5cc7b47dc77e2f3465e5e47176ac',
+        'com.android.tools.build:apkzlib:3.4.0:apkzlib-3.4.0.jar:8653c85f5fdf1dde840e8b8af7396aeb79c34b66e541b5860059616006535592',
-        'com.android.tools.build:builder-model:3.3.2:builder-model-3.3.2.jar:055e3db0ecee9e06b9f024034999a29cd92cb1885207b37542126bd8bcc57f46',
+        'com.android.tools.build:builder-model:3.4.0:builder-model-3.4.0.jar:a88f138124a9f016a70bcb4760359a502f65c7deed56507ee4014f4dd9ea853b',
-        'com.android.tools.build:builder-test-api:3.3.2:builder-test-api-3.3.2.jar:0b2e4cd7615bbcad14a3c91fe45ae26693508d06e40ba06c5968b8bc24416618',
+        'com.android.tools.build:builder-test-api:3.4.0:builder-test-api-3.4.0.jar:31089ab1ec19ca7687a010867d2f3807513c805b8226979706f4247b5d4df26f',
-        'com.android.tools.build:builder:3.3.2:builder-3.3.2.jar:65649704da7aef0487235fd326f0f2e99ed5cf958e80f204496e6e08a42bd9f5',
+        'com.android.tools.build:builder:3.4.0:builder-3.4.0.jar:476221b5203a7f50089bf185ed95000a34b6f5020ef0a17815afd58606922679',
-        'com.android.tools.build:gradle-api:3.3.2:gradle-api-3.3.2.jar:3cbd47e41bb70330dd72ec2c9fe51e6173554b484a03829b5a2de9e00841e040',
+        'com.android.tools.build:gradle-api:3.4.0:gradle-api-3.4.0.jar:215eca38f6719213c2f492b4d622cdd11676c66c9871f8a2aed0c66d00175628',
-        'com.android.tools.build:manifest-merger:26.3.2:manifest-merger-26.3.2.jar:05c4a6d8b02fb9f08744876477d0a68547c03a8a9069b1f086684fa04af97c33',
+        'com.android.tools.build:manifest-merger:26.4.0:manifest-merger-26.4.0.jar:29e45e690dedd165035e97c21c2ca94d0bd4ec16b6b210daa26669a582b6f220',
-        'com.android.tools.ddms:ddmlib:26.3.2:ddmlib-26.3.2.jar:d248da8a563d6e46d2c7ebbf371a4877e00510f4ca763c0bb272d5a281bf8b85',
+        'com.android.tools.ddms:ddmlib:26.4.0:ddmlib-26.4.0.jar:93f56fe4630c3166adbd6c51d7bb602d96abb91b07ba5b1165fdcd071e88c940',
-        'com.android.tools.external.com-intellij:intellij-core:26.3.2:intellij-core-26.3.2.jar:6c5ecc968230e9f4dcd0fef28885379feace1f0cd8130de6f61d649c86139bf3',
+        'com.android.tools.external.com-intellij:intellij-core:26.4.0:intellij-core-26.4.0.jar:30cb0e879d4424de9677a50b537fb628636b4a50f5470af5e52437980c41421f',
-        'com.android.tools.external.com-intellij:kotlin-compiler:26.3.2:kotlin-compiler-26.3.2.jar:1007d9b07ccb49cd8eaf30fda10ed4681d4714f2f9ab2ecda39b4e539cc51bbe',
+        'com.android.tools.external.com-intellij:kotlin-compiler:26.4.0:kotlin-compiler-26.4.0.jar:dd1fe225c31a0e012dc025336363a5b783e2c5c20ffb69e77f8f57e89420d998',
-        'com.android.tools.external.org-jetbrains:uast:26.3.2:uast-26.3.2.jar:5d1833e562ea4f38a89708dfde695f0a162cbd39d003d3dde818c3fdc2b05317',
+        'com.android.tools.external.org-jetbrains:uast:26.4.0:uast-26.4.0.jar:f25f3285b775a983327583ff6584dea54e447813ef69e0ce08b05a45b5f4aab0',
-        'com.android.tools.layoutlib:layoutlib-api:26.3.2:layoutlib-api-26.3.2.jar:d7e61e874ab95f5c350dd38b6a95b5c9dbe0083a02001884264cdb390cb255b8',
+        'com.android.tools.layoutlib:layoutlib-api:26.4.0:layoutlib-api-26.4.0.jar:52128f5cf293b224072be361919bfd416e59480ab7264ddcdbbf046b0d7a12e3',
-        'com.android.tools.lint:lint-api:26.3.2:lint-api-26.3.2.jar:5867dfd7fb4a4e161a816a5d29d045f9b542d34594c00a1efec46fb4cd0e1033',
+        'com.android.tools.lint:lint-api:26.4.0:lint-api-26.4.0.jar:fdb8fca8ae4c254f438338d03d72605e00ed106f2d5550405af41ca1c8509401',
-        'com.android.tools.lint:lint-checks:26.3.2:lint-checks-26.3.2.jar:4b163b9c93790d2771e92ba8de58a0d9e0671ffcf2ccef3cf496efd442e27517',
+        'com.android.tools.lint:lint-checks:26.4.0:lint-checks-26.4.0.jar:4ff52d40488cd3e22b9c6b2eb67784e0c3269d0b42ef9d17689cd75a7b2bceb4',
-        'com.android.tools.lint:lint-gradle-api:26.3.2:lint-gradle-api-26.3.2.jar:54cb282e0c054f9bed3f51302ce08b003c8ab7961dfd5a4f6de26c23cc23062f',
+        'com.android.tools.lint:lint-gradle-api:26.4.0:lint-gradle-api-26.4.0.jar:714b7a85c7d2aa10daeab16e969fe7530c659d0728a7f24021da456870418d0f',
-        'com.android.tools.lint:lint-gradle:26.3.2:lint-gradle-26.3.2.jar:bb139615f4ce97d42cc394b9389b49b76a6eb85be6785a5d272991543b519013',
+        'com.android.tools.lint:lint-gradle:26.4.0:lint-gradle-26.4.0.jar:b8c130d273f522388734457e1b96790f41528fcec6fda9e8eaa4e4d95a07cfbb',
-        'com.android.tools.lint:lint:26.3.2:lint-26.3.2.jar:ef7b369f8a56a92ccb0f4c1c357666b9339e4a711a9d84747d446441746cfe4e',
+        'com.android.tools.lint:lint:26.4.0:lint-26.4.0.jar:83aa062fb0405b60ed358d858c8c2955e1bae44a455b498068c6a60988755f00',
-        'com.android.tools:annotations:26.3.2:annotations-26.3.2.jar:5bcce8e98b6a2f5ccf13ebcefd8f734e0b35f8b19e456575665631442ce1f7a1',
+        'com.android.tools:annotations:26.4.0:annotations-26.4.0.jar:a7955b8e19c3a2a861d6faa43a58b7c0d46ea9112188ee3e235c6f9f439ecc1a',
-        'com.android.tools:common:26.3.2:common-26.3.2.jar:d9f8e7f0669e9a701568e3db6a87c89cf12d8fa6811c9991e969f950215ecfac',
+        'com.android.tools:common:26.4.0:common-26.4.0.jar:ea40b94b3c1284ea7700f011388e2906a8363a66abd902891722b3c557984852',
-        'com.android.tools:dvlib:26.3.2:dvlib-26.3.2.jar:d84aad56161c7773579303d69714ded6897c64c6ddfd7d456e453231e4dfe811',
+        'com.android.tools:dvlib:26.4.0:dvlib-26.4.0.jar:23af89c535b01ba36ceed1b6b309b672814eba624e643cd7dedf0519edad50cc',
-        'com.android.tools:repository:26.3.2:repository-26.3.2.jar:da611eeb06e9ab8750d25b9e2901e10db8e5ec6304eb4c8b7103d39e0921ea40',
+        'com.android.tools:repository:26.4.0:repository-26.4.0.jar:3d1763ab46199374dc6d94129bba11c70f1d5857e2c81a3ac4898abca40b176b',
-        'com.android.tools:sdk-common:26.3.2:sdk-common-26.3.2.jar:82823a3bf25e64fac33a286490f0cf5ac50c2cdb3c540149b030896bb44bf96c',
+        'com.android.tools:sdk-common:26.4.0:sdk-common-26.4.0.jar:78a522525b30ffc6b7bf1299c831d24ce385f68a9f4878f8f752e9baefa31b0f',
-        'com.android.tools:sdklib:26.3.2:sdklib-26.3.2.jar:424d15492af67321900963238646d27495ab60de2a5b19e6a416963bc5d6932b',
+        'com.android.tools:sdklib:26.4.0:sdklib-26.4.0.jar:b854c23892013a326d761cf071c72cf3e038ed0469d10f4a356829fa56e4c132',
         'com.google.code.findbugs:jsr305:1.3.9:jsr305-1.3.9.jar:905721a0eea90a81534abb7ee6ef4ea2e5e645fa1def0a5cd88402df1b46c9ed',
         'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
         'com.google.code.gson:gson:2.8.0:gson-2.8.0.jar:c6221763bd79c4f1c3dc7f750b5f29a0bb38b367b81314c4f71896e340c40825',
-        'com.google.dagger:dagger-compiler:2.19:dagger-compiler-2.19.jar:27a4b202a2de908182edb261f8c0a264e08e5e4733d7514bc7fbf0d31da5c0fc',
+        'com.google.dagger:dagger-compiler:2.22.1:dagger-compiler-2.22.1.jar:e5f28302cbe70a79d3620cddebfb8ec0736814f3980ffe1e673bfe3342f507d3',
-        'com.google.dagger:dagger-producers:2.19:dagger-producers-2.19.jar:a17663abe0fc38b676026950907d4c5f5e2bf338375415861eaff6e3bdb0b768',
+        'com.google.dagger:dagger-producers:2.22.1:dagger-producers-2.22.1.jar:f834a0082014213a68ff06a0f048d750178d02196c58b0b15beb367d32b97e35',
-        'com.google.dagger:dagger-spi:2.19:dagger-spi-2.19.jar:e7a6379d82c841f6aac2866948ad1eed716528707814602842a8d844ce04e2e1',
+        'com.google.dagger:dagger-spi:2.22.1:dagger-spi-2.22.1.jar:4b0b922793b3bcb91b99fabb75dba77c68afd7ae4c5f0c4fd6ba681f0a291c7d',
-        'com.google.dagger:dagger:2.19:dagger-2.19.jar:514b6f1e0727c6572e1d65cb27e4ae668b7aeaeb93a29515182965265b609939',
+        'com.google.dagger:dagger:2.22.1:dagger-2.22.1.jar:329d4340f24c4f5717af016c097e90668bfea2a5376e6aa9964b01cef3fd241a',
         '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: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 +48,7 @@ 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:1.9:commons-codec-1.9.jar:ad19d2601c3abf0b946b5c3a4113e226a8c1e3305e395b90013b78dd94a723ce',
+        'commons-codec:commons-codec:1.10:commons-codec-1.10.jar:4241dfa94e711d435f29a4604a3e2de5c4aa3c165e23bd066be6fc1fc4309569',
         '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',
@@ -60,9 +60,9 @@ 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:4.5.2:httpclient-4.5.2.jar:0dffc621400d6c632f55787d996b8aeca36b30746a716e079a985f24d8074057',
+        'org.apache.httpcomponents:httpclient:4.5.6:httpclient-4.5.6.jar:c03f813195e7a80e3608d0ddd8da80b21696a4c92a6a2298865bf149071551c7',
-        'org.apache.httpcomponents:httpcore:4.4.5:httpcore-4.4.5.jar:64d5453874cab7e40a7065cb01a9a9ca1053845a9786b478878b679e0580cec3',
+        'org.apache.httpcomponents:httpcore:4.4.10:httpcore-4.4.10.jar:78ba1096561957db1b55200a159b648876430342d15d461277e62360da19f6fd',
-        'org.apache.httpcomponents:httpmime:4.5.2:httpmime-4.5.2.jar:231a3f7e4962053db2be8461d5422e68fc458a3a7dd7d8ada803a348e21f8f07',
+        'org.apache.httpcomponents:httpmime:4.5.6:httpmime-4.5.6.jar:0b2b1102c18d3c7e05a77214b9b7501a6f6056174ae5604e0e256776eda7553e',
         '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',

bramble-api/build.gradle

@@ -7,7 +7,7 @@ apply plugin: 'witness'
 apply from: 'witness.gradle'
 
 dependencies {
-	implementation "com.google.dagger:dagger:2.19"
+	implementation "com.google.dagger:dagger:2.22.1"
 	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

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

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

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

@@ -33,7 +33,8 @@ public abstract class BdfIncomingMessageHook implements IncomingMessageHook {
 	/**
 	 * Called once for each incoming message that passes validation.
 	 *
-	 * @return whether or not this message should be shared
+	 * @param txn A read-write transaction
+	 * @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

@@ -1,6 +1,8 @@
 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;
@@ -96,14 +98,18 @@ public interface ClientHelper {
 
 	BdfList toList(Author a);
 
-	byte[] sign(String label, BdfList toSign, byte[] privateKey)
+	byte[] sign(String label, BdfList toSign, PrivateKey privateKey)
 			throws FormatException, GeneralSecurityException;
 
 	void verifySignature(byte[] signature, String label, BdfList signed,
-			byte[] publicKey) throws FormatException, GeneralSecurityException;
+			PublicKey publicKey)
+			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

@@ -1,5 +1,6 @@
 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;
@@ -8,7 +9,6 @@ import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
-import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
 import static org.briarproject.bramble.util.StringUtils.toUtf8;
 
 @Immutable
@@ -21,21 +21,17 @@ public class Contact {
 	@Nullable
 	private final String alias;
 	@Nullable
-	private final byte[] handshakePublicKey;
+	private final PublicKey handshakePublicKey;
 	private final boolean verified;
 
 	public Contact(ContactId id, Author author, AuthorId localAuthorId,
-			@Nullable String alias, @Nullable byte[] handshakePublicKey,
+			@Nullable String alias, @Nullable PublicKey handshakePublicKey,
 			boolean verified) {
 		if (alias != null) {
 			int aliasLength = toUtf8(alias).length;
 			if (aliasLength == 0 || aliasLength > MAX_AUTHOR_NAME_LENGTH)
 				throw new IllegalArgumentException();
 		}
-		if (handshakePublicKey != null && (handshakePublicKey.length == 0 ||
-				handshakePublicKey.length > MAX_PUBLIC_KEY_LENGTH)) {
-			throw new IllegalArgumentException();
-		}
 		this.id = id;
 		this.author = author;
 		this.localAuthorId = localAuthorId;
@@ -62,7 +58,7 @@ public class Contact {
 	}
 
 	@Nullable
-	public byte[] getHandshakePublicKey() {
+	public PublicKey getHandshakePublicKey() {
 		return handshakePublicKey;
 	}
 

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

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

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

@@ -1,7 +1,10 @@
 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;
@@ -53,34 +56,34 @@ public interface ContactManager {
 			throws DbException;
 
 	/**
-	 * Returns the static link that needs to be sent to the contact to be added.
+	 * Returns the handshake link that needs to be sent to a contact we want
+	 * to add.
 	 */
-	String getRemoteContactLink();
+	String getHandshakeLink() throws DbException;
 
 	/**
-	 * Returns true if the given link is syntactically valid.
+	 * Creates a {@link PendingContact} from the given handshake link and
-	 */
+	 * alias, adds it to the database and returns it.
-	boolean isValidRemoteContactLink(String link);
-
-	/**
-	 * Requests a new contact to be added via the given {@code link}.
 	 *
-	 * @param link The link received from the contact we want to add.
+	 * @param link The handshake link received from the contact we want to add
-	 * @param alias The alias the user has given this contact.
+	 * @param alias The alias the user has given this contact
-	 * @return A PendingContact representing the contact to be added.
+	 * @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 addRemoteContactRequest(String link, String alias);
+	PendingContact addPendingContact(String link, String alias)
+			throws DbException, FormatException;
 
 	/**
 	 * Returns a list of {@link PendingContact}s.
 	 */
-	Collection<PendingContact> getPendingContacts();
+	Collection<PendingContact> getPendingContacts() throws DbException;
 
 	/**
-	 * Removes a {@link PendingContact} that is in state
+	 * Removes a {@link PendingContact}.
-	 * {@link PendingContactState FAILED}.
 	 */
-	void removePendingContact(PendingContact pendingContact);
+	void removePendingContact(PendingContactId p) throws DbException;
 
 	/**
 	 * Returns the contact with the given ID.
@@ -91,7 +94,7 @@ public interface ContactManager {
 	 * Returns the contact with the given remoteAuthorId
 	 * that was added by the LocalAuthor with the given localAuthorId
 	 *
-	 * @throws org.briarproject.bramble.api.db.NoSuchContactException
+	 * @throws NoSuchContactException If the contact is not in the database
 	 */
 	Contact getContact(AuthorId remoteAuthorId, AuthorId localAuthorId)
 			throws DbException;
@@ -100,7 +103,7 @@ public interface ContactManager {
 	 * Returns the contact with the given remoteAuthorId
 	 * that was added by the LocalAuthor with the given localAuthorId
 	 *
-	 * @throws org.briarproject.bramble.api.db.NoSuchContactException
+	 * @throws NoSuchContactException If the contact is not in the database
 	 */
 	Contact getContact(Transaction txn, AuthorId remoteAuthorId,
 			AuthorId localAuthorId) throws DbException;
@@ -156,8 +159,20 @@ 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

@@ -0,0 +1,34 @@
+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

@@ -1,5 +1,6 @@
 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;
@@ -9,12 +10,12 @@ import javax.annotation.concurrent.Immutable;
 public class PendingContact {
 
 	private final PendingContactId id;
-	private final byte[] publicKey;
+	private final PublicKey publicKey;
 	private final String alias;
 	private final PendingContactState state;
 	private final long timestamp;
 
-	public PendingContact(PendingContactId id, byte[] publicKey,
+	public PendingContact(PendingContactId id, PublicKey publicKey,
 			String alias, PendingContactState state, long timestamp) {
 		this.id = id;
 		this.publicKey = publicKey;
@@ -27,7 +28,7 @@ public class PendingContact {
 		return id;
 	}
 
-	public byte[] getPublicKey() {
+	public PublicKey getPublicKey() {
 		return publicKey;
 	}
 

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

@@ -3,6 +3,7 @@ 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;
 
 /**
@@ -17,9 +18,8 @@ public class PendingContactId extends UniqueId {
 		super(id);
 	}
 
-
 	@Override
-	public boolean equals(Object o) {
+	public boolean equals(@Nullable Object o) {
 		return o instanceof PendingContactId && super.equals(o);
 	}
 }

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

@@ -1,4 +1,4 @@
-package org.briarproject.briar.api.introduction.event;
+package org.briarproject.bramble.api.contact.event;
 
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.event.Event;
@@ -8,11 +8,11 @@ import javax.annotation.concurrent.Immutable;
 
 @Immutable
 @NotNullByDefault
-public class IntroductionSucceededEvent extends Event {
+public class ContactAddedRemotelyEvent extends Event {
 
 	private final Contact contact;
 
-	public IntroductionSucceededEvent(Contact contact) {
+	public ContactAddedRemotelyEvent(Contact contact) {
 		this.contact = contact;
 	}
 

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

@@ -0,0 +1,26 @@
+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/crypto/AgreementPrivateKey.java

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

@@ -0,0 +1,35 @@
+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, byte[] privateKey)
+	byte[] sign(String label, byte[] toSign, PrivateKey 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,
-			byte[] publicKey) throws GeneralSecurityException;
+			PublicKey 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

@@ -7,11 +7,21 @@ 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/KeyPair.java

@@ -15,6 +15,8 @@ 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

@@ -8,6 +8,11 @@ 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

@@ -8,6 +8,11 @@ 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

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

@@ -0,0 +1,35 @@
+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

@@ -1,7 +1,6 @@
 package org.briarproject.bramble.api.crypto;
 
 import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.transport.HandshakeKeys;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
 /**
@@ -11,35 +10,29 @@ import org.briarproject.bramble.api.transport.TransportKeys;
 public interface TransportCrypto {
 
 	/**
-	 * Derives initial transport keys for the given transport in the given
+	 * Derives initial rotation mode transport keys for the given transport in
-	 * time period from the given root key.
+	 * the given time period from the given root key.
 	 *
-	 * @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 deriveTransportKeys(TransportId t, SecretKey rootKey,
+	TransportKeys deriveRotationKeys(TransportId t, SecretKey rootKey,
 			long timePeriod, boolean alice, boolean active);
 
-	/**
-	 * Rotates the given transport keys to the given time period. If the keys
-	 * are for the given period or any later period they are not rotated.
-	 */
-	TransportKeys rotateTransportKeys(TransportKeys k, long timePeriod);
-
 	/**
 	 * Derives handshake keys for the given transport in the given time period
 	 * from the given root key.
 	 *
-	 * @param alice whether the keys are for use by Alice or Bob.
+	 * @param alice Whether the keys are for use by Alice or Bob
 	 */
-	HandshakeKeys deriveHandshakeKeys(TransportId t, SecretKey rootKey,
+	TransportKeys deriveHandshakeKeys(TransportId t, SecretKey rootKey,
 			long timePeriod, boolean alice);
 
 	/**
-	 * Updates the given handshake keys to the given time period. If the keys
+	 * 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.
 	 */
-	HandshakeKeys updateHandshakeKeys(HandshakeKeys k, long timePeriod);
+	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/DatabaseComponent.java

@@ -4,10 +4,12 @@ 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.LocalAuthor;
+import org.briarproject.bramble.api.identity.Identity;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.settings.Settings;
@@ -22,11 +24,8 @@ 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.HandshakeKeySet;
+import org.briarproject.bramble.api.transport.KeySetId;
-import org.briarproject.bramble.api.transport.HandshakeKeySetId;
-import org.briarproject.bramble.api.transport.HandshakeKeys;
 import org.briarproject.bramble.api.transport.TransportKeySet;
-import org.briarproject.bramble.api.transport.TransportKeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.util.Collection;
@@ -114,23 +113,9 @@ public interface DatabaseComponent {
 	void addGroup(Transaction txn, Group g) throws DbException;
 
 	/**
-	 * Stores the given handshake keys for the given contact and returns a
+	 * Stores an identity.
-	 * key set ID.
 	 */
-	HandshakeKeySetId addHandshakeKeys(Transaction txn, ContactId c,
+	void addIdentity(Transaction txn, Identity i) throws DbException;
-			HandshakeKeys k) throws DbException;
-
-	/**
-	 * Stores the given handshake keys for the given pending contact and
-	 * returns a key set ID.
-	 */
-	HandshakeKeySetId addHandshakeKeys(Transaction txn, PendingContactId p,
-			HandshakeKeys k) throws DbException;
-
-	/**
-	 * Stores a local pseudonym.
-	 */
-	void addLocalAuthor(Transaction txn, LocalAuthor a) throws DbException;
 
 	/**
 	 * Stores a local message.
@@ -154,7 +139,14 @@ public interface DatabaseComponent {
 	 * Stores the given transport keys for the given contact and returns a
 	 * key set ID.
 	 */
-	TransportKeySetId addTransportKeys(Transaction txn, ContactId c,
+	KeySetId addTransportKeys(Transaction txn, ContactId c, TransportKeys k)
+			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;
 
 	/**
@@ -174,12 +166,12 @@ public interface DatabaseComponent {
 	boolean containsGroup(Transaction txn, GroupId g) throws DbException;
 
 	/**
-	 * Returns true if the database contains the given local author.
+	 * Returns true if the database contains an identity for the given
+	 * pseudonym.
 	 * <p/>
 	 * Read-only.
 	 */
-	boolean containsLocalAuthor(Transaction txn, AuthorId local)
+	boolean containsIdentity(Transaction txn, AuthorId a) throws DbException;
-			throws DbException;
 
 	/**
 	 * Returns true if the database contains the given pending contact.
@@ -274,7 +266,7 @@ public interface DatabaseComponent {
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<ContactId> getContacts(Transaction txn, AuthorId a)
+	Collection<ContactId> getContacts(Transaction txn, AuthorId local)
 			throws DbException;
 
 	/**
@@ -309,26 +301,18 @@ public interface DatabaseComponent {
 			throws DbException;
 
 	/**
-	 * Returns all handshake keys for the given transport.
+	 * Returns the identity for the local pseudonym with the given ID.
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<HandshakeKeySet> getHandshakeKeys(Transaction txn, TransportId t)
+	Identity getIdentity(Transaction txn, AuthorId a) throws DbException;
-			throws DbException;
 
 	/**
-	 * Returns the local pseudonym with the given ID.
+	 * Returns the identities for all local pseudonyms.
 	 * <p/>
 	 * Read-only.
 	 */
-	LocalAuthor getLocalAuthor(Transaction txn, AuthorId a) throws DbException;
+	Collection<Identity> getIdentities(Transaction txn) throws DbException;
-
-	/**
-	 * Returns all local pseudonyms.
-	 * <p/>
-	 * Read-only.
-	 */
-	Collection<LocalAuthor> getLocalAuthors(Transaction txn) throws DbException;
 
 	/**
 	 * Returns the message with the given ID.
@@ -487,17 +471,11 @@ public interface DatabaseComponent {
 	Collection<TransportKeySet> getTransportKeys(Transaction txn, TransportId t)
 			throws DbException;
 
-	/**
-	 * Increments the outgoing stream counter for the given handshake keys.
-	 */
-	void incrementStreamCounter(Transaction txn, TransportId t,
-			HandshakeKeySetId k) throws DbException;
-
 	/**
 	 * Increments the outgoing stream counter for the given transport keys.
 	 */
-	void incrementStreamCounter(Transaction txn, TransportId t,
+	void incrementStreamCounter(Transaction txn, TransportId t, KeySetId k)
-			TransportKeySetId k) throws DbException;
+			throws DbException;
 
 	/**
 	 * Merges the given metadata with the existing metadata for the given
@@ -553,15 +531,9 @@ public interface DatabaseComponent {
 	void removeGroup(Transaction txn, Group g) throws DbException;
 
 	/**
-	 * Removes the given handshake keys from the database.
+	 * Removes an identity (and all associated state) from the database.
 	 */
-	void removeHandshakeKeys(Transaction txn, TransportId t,
+	void removeIdentity(Transaction txn, AuthorId a) throws DbException;
-			HandshakeKeySetId k) throws DbException;
-
-	/**
-	 * Removes a local pseudonym (and all associated state) from the database.
-	 */
-	void removeLocalAuthor(Transaction txn, AuthorId a) throws DbException;
 
 	/**
 	 * Removes a message (and all associated state) from the database.
@@ -582,8 +554,8 @@ public interface DatabaseComponent {
 	/**
 	 * Removes the given transport keys from the database.
 	 */
-	void removeTransportKeys(Transaction txn, TransportId t,
+	void removeTransportKeys(Transaction txn, TransportId t, KeySetId k)
-			TransportKeySetId k) throws DbException;
+			throws DbException;
 
 	/**
 	 * Marks the given contact as verified.
@@ -620,31 +592,22 @@ public interface DatabaseComponent {
 			Collection<MessageId> dependencies) throws DbException;
 
 	/**
-	 * Sets the reordering window for the given transport key set in the given
+	 * Sets the handshake key pair for the identity with the given ID.
-	 * time period.
 	 */
-	void setReorderingWindow(Transaction txn, TransportKeySetId k,
+	void setHandshakeKeyPair(Transaction txn, AuthorId local,
-			TransportId t, long timePeriod, long base, byte[] bitmap)
+			PublicKey publicKey, PrivateKey privateKey) throws DbException;
-			throws DbException;
 
 	/**
-	 * Sets the reordering window for the given handshake key set in the given
+	 * Sets the reordering window for the given transport keys in the given
 	 * time period.
 	 */
-	void setReorderingWindow(Transaction txn, HandshakeKeySetId k,
+	void setReorderingWindow(Transaction txn, KeySetId k, TransportId t,
-			TransportId t, long timePeriod, long base, byte[] bitmap)
+			long timePeriod, long base, byte[] bitmap) throws DbException;
-			throws DbException;
 
 	/**
 	 * Marks the given transport keys as usable for outgoing streams.
 	 */
-	void setTransportKeysActive(Transaction txn, TransportId t,
+	void setTransportKeysActive(Transaction txn, TransportId t, KeySetId k)
-			TransportKeySetId k) throws DbException;
-
-	/**
-	 * Stores the given handshake keys, deleting any keys they have replaced.
-	 */
-	void updateHandshakeKeys(Transaction txn, Collection<HandshakeKeySet> keys)
 			throws DbException;
 
 	/**

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

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

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

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

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

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

@@ -0,0 +1,88 @@
+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 a local identity with the given name.
+	 * Creates an identity with the given name. The identity includes a
+	 * handshake key pair.
 	 */
 	@CryptoExecutor
-	LocalAuthor createLocalAuthor(String name);
+	Identity createIdentity(String name);
 
 	/**
-	 * Registers the given local identity with the manager. The identity is
+	 * Registers the given identity with the manager. This method should be
-	 * not stored until {@link #storeLocalAuthor()} is called.
+	 * called before {@link LifecycleManager#startServices(SecretKey)}. The
+	 * identity is stored when {@link LifecycleManager#startServices(SecretKey)}
+	 * is called. The identity must include a handshake key pair.
 	 */
-	void registerLocalAuthor(LocalAuthor a);
+	void registerIdentity(Identity i);
-
-	/**
-	 * 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.
@@ -33,7 +33,15 @@ 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

@@ -1,11 +1,12 @@
 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.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
+import static org.briarproject.bramble.api.crypto.CryptoConstants.KEY_TYPE_SIGNATURE;
 
 /**
  * A pseudonym for the local user.
@@ -14,62 +15,20 @@ import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_K
 @NotNullByDefault
 public class LocalAuthor extends Author {
 
-	private final byte[] privateKey;
+	private final PrivateKey privateKey;
-	@Nullable
-	private final byte[] handshakePublicKey, handshakePrivateKey;
-	private final long created;
 
 	public LocalAuthor(AuthorId id, int formatVersion, String name,
-			byte[] publicKey, byte[] privateKey, long created) {
+			PublicKey publicKey, PrivateKey privateKey) {
 		super(id, formatVersion, name, publicKey);
-		this.privateKey = privateKey;
+		if (!privateKey.getKeyType().equals(KEY_TYPE_SIGNATURE))
-		this.created = created;
-		handshakePublicKey = null;
-		handshakePrivateKey = null;
-	}
-
-	public LocalAuthor(AuthorId id, int formatVersion, String name,
-			byte[] publicKey, byte[] privateKey, byte[] handshakePublicKey,
-			byte[] handshakePrivateKey, long created) {
-		super(id, formatVersion, name, publicKey);
-		if (handshakePublicKey.length == 0 ||
-				handshakePublicKey.length > MAX_PUBLIC_KEY_LENGTH) {
 			throw new IllegalArgumentException();
-		}
 		this.privateKey = privateKey;
-		this.handshakePublicKey = handshakePublicKey;
-		this.handshakePrivateKey = handshakePrivateKey;
-		this.created = created;
 	}
 
 	/**
 	 * Returns the private key used to generate the pseudonym's signatures.
 	 */
-	public byte[] getPrivateKey() {
+	public PrivateKey getPrivateKey() {
 		return privateKey;
 	}
-
-	/**
-	 * Returns the public key used for handshaking, or null if no key exists.
-	 */
-	@Nullable
-	public byte[] getHandshakePublicKey() {
-		return handshakePublicKey;
-	}
-
-	/**
-	 * Returns the private key used for handshaking, or null if no key exists.
-	 */
-	@Nullable
-	public byte[] getHandshakePrivateKey() {
-		return handshakePrivateKey;
-	}
-
-	/**
-	 * Returns the time the pseudonym was created, in milliseconds since the
-	 * Unix epoch.
-	 */
-	public long getTimeCreated() {
-		return created;
-	}
 }

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

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

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

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

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

@@ -1,20 +0,0 @@
-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, starting {@link Client Clients}, starting
+ * Manages the lifecycle of the app: opening and closing the
- * and stopping {@link Service Services}, shutting down
+ * {@link DatabaseComponent} starting and stopping {@link Service Services},
- * {@link ExecutorService ExecutorServices}, and opening and closing the
+ * and shutting down {@link ExecutorService ExecutorServices}.
- * {@link DatabaseComponent}.
  */
 @NotNullByDefault
 public interface LifecycleManager {
@@ -42,18 +42,19 @@ 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)}.
@@ -62,7 +63,7 @@ public interface LifecycleManager {
 
 	/**
 	 * Opens the {@link DatabaseComponent} using the given key and starts any
-	 * registered {@link Client Clients} and {@link Service Services}.
+	 * registered {@link Service Services}.
 	 */
 	StartResult startServices(SecretKey dbKey);
 
@@ -80,8 +81,7 @@ public interface LifecycleManager {
 
 	/**
 	 * Waits for the {@link DatabaseComponent} to be opened and all registered
-	 * {@link Client Clients} and {@link Service Services} to start before
+	 * {@link Service Services} to start before returning.
-	 * returning.
 	 */
 	void waitForStartup() throws InterruptedException;
 
@@ -97,4 +97,13 @@ 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

@@ -6,10 +6,20 @@ import javax.annotation.Nullable;
 public class NullSafety {
 
 	/**
-	 * Stand-in for `Objects.requireNonNull()`.
+	 * Stand-in for {@code 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

@@ -1,14 +0,0 @@
-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

@@ -11,7 +11,8 @@ public interface IncomingMessageHook {
 	/**
 	 * Called once for each incoming message that passes validation.
 	 *
-	 * @return whether or not this message should be shared
+	 * @param txn A read-write transaction
+	 * @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/AbstractTransportKeys.java

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

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

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

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

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

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

@@ -8,8 +8,8 @@ import javax.annotation.concurrent.Immutable;
 import static org.briarproject.bramble.api.transport.TransportConstants.REORDERING_WINDOW_SIZE;
 
 /**
- * Contains transport keys for receiving streams from a given contact over a
+ * Contains transport keys for receiving streams from a given contact or
- * given transport in a given time period.
+ * pending contact over a given transport in a given time period.
  */
 @Immutable
 @NotNullByDefault

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

@@ -1,6 +1,7 @@
 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;
@@ -18,23 +19,51 @@ public interface KeyManager {
 
 	/**
 	 * Informs the key manager that a new contact has been added. Derives and
-	 * stores a set of transport keys for communicating with the contact over
+	 * stores a set of rotation mode transport keys for communicating with the
-	 * each transport and returns the key set IDs.
+	 * 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
+	 * @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, TransportKeySetId> addContact(Transaction txn, ContactId c,
+	Map<TransportId, KeySetId> addContactWithRotationKeys(Transaction txn,
-			SecretKey rootKey, long timestamp, boolean alice, boolean active)
+			ContactId c, SecretKey rootKey, long timestamp, boolean alice,
+			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;
 
 	/**
 	 * Marks the given transport keys as usable for outgoing streams.
 	 */
-	void activateKeys(Transaction txn, Map<TransportId, TransportKeySetId> keys)
+	void activateKeys(Transaction txn, Map<TransportId, KeySetId> keys)
 			throws DbException;
 
 	/**
@@ -43,15 +72,28 @@ 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 or the
+	 * contact over the given transport, or null if an error occurs.
-	 * 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/KeySetId.java

@@ -5,17 +5,16 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import javax.annotation.concurrent.Immutable;
 
 /**
- * Type-safe wrapper for an integer that uniquely identifies a
+ * Type-safe wrapper for an integer that uniquely identifies a set of
- * {@link HandshakeKeySet set of handshake keys} within the scope of the local
+ * {@link TransportKeySet transport keys} within the scope of the local device.
- * device.
  */
 @Immutable
 @NotNullByDefault
-public class HandshakeKeySetId {
+public class KeySetId {
 
 	private final int id;
 
-	public HandshakeKeySetId(int id) {
+	public KeySetId(int id) {
 		this.id = id;
 	}
 
@@ -30,7 +29,6 @@ public class HandshakeKeySetId {
 
 	@Override
 	public boolean equals(Object o) {
-		return o instanceof HandshakeKeySetId &&
+		return o instanceof KeySetId && id == ((KeySetId) o).id;
-				id == ((HandshakeKeySetId) o).id;
 	}
 }

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

@@ -6,8 +6,8 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import javax.annotation.concurrent.Immutable;
 
 /**
- * Contains transport keys for sending streams to a given contact over a given
+ * Contains transport keys for sending streams to a given contact or pending
- * transport in a given time period.
+ * contact over a given transport in a given time period.
  */
 @Immutable
 @NotNullByDefault

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

@@ -1,34 +1,53 @@
 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(ContactId contactId, TransportId transportId,
+	public StreamContext(@Nullable ContactId contactId,
-			SecretKey tagKey, SecretKey headerKey, long streamNumber) {
+			@Nullable PendingContactId pendingContactId,
+			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;
 	}
@@ -44,4 +63,8 @@ public class StreamContext {
 	public long getStreamNumber() {
 		return streamNumber;
 	}
+
+	public boolean isHandshakeMode() {
+		return handshakeMode;
+	}
 }

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

@@ -1,37 +1,52 @@
 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 over a given transport.
+ * A set of keys for communicating with a given contact or pending contact
- * Unlike a {@link HandshakeKeySet} these keys provide forward secrecy.
+ * over a given transport.
  */
 @Immutable
 @NotNullByDefault
 public class TransportKeySet {
 
-	private final TransportKeySetId keySetId;
+	private final KeySetId keySetId;
+	@Nullable
 	private final ContactId contactId;
+	@Nullable
+	private final PendingContactId pendingContactId;
 	private final TransportKeys keys;
 
-	public TransportKeySet(TransportKeySetId keySetId, ContactId contactId,
+	public TransportKeySet(KeySetId keySetId, @Nullable ContactId contactId,
-			TransportKeys keys) {
+			@Nullable PendingContactId pendingContactId, TransportKeys keys) {
+		requireExactlyOneNull(contactId, pendingContactId);
 		this.keySetId = keySetId;
 		this.contactId = contactId;
+		this.pendingContactId = pendingContactId;
 		this.keys = keys;
 	}
 
-	public TransportKeySetId getKeySetId() {
+	public KeySetId getKeySetId() {
 		return keySetId;
 	}
 
+	@Nullable
 	public ContactId getContactId() {
 		return contactId;
 	}
 
+	@Nullable
+	public PendingContactId getPendingContactId() {
+		return pendingContactId;
+	}
+
 	public TransportKeys getKeys() {
 		return keys;
 	}

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

@@ -1,38 +0,0 @@
-package org.briarproject.bramble.api.transport;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-/**
- * Type-safe wrapper for an integer that uniquely identifies a
- * {@link TransportKeySet set of transport keys} within the scope of the local
- * device.
- * <p/>
- * Key sets created on a given device must have increasing identifiers.
- */
-@Immutable
-@NotNullByDefault
-public class TransportKeySetId {
-
-	private final int id;
-
-	public TransportKeySetId(int id) {
-		this.id = id;
-	}
-
-	public int getInt() {
-		return id;
-	}
-
-	@Override
-	public int hashCode() {
-		return id;
-	}
-
-	@Override
-	public boolean equals(Object o) {
-		return o instanceof TransportKeySetId &&
-				id == ((TransportKeySetId) o).id;
-	}
-}

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

@@ -1,20 +1,108 @@
 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 over a given transport. Unlike
+ * Keys for communicating with a given contact or pending contact over a given
- * {@link HandshakeKeys} these keys provide forward secrecy.
+ * transport.
  */
 @Immutable
 @NotNullByDefault
-public class TransportKeys extends AbstractTransportKeys {
+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) {
-		super(transportId, inPrev, inCurr, inNext, outCurr);
+		this(transportId, inPrev, inCurr, inNext, outCurr, null, false);
+	}
+
+	/**
+	 * 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())
+			throw new IllegalArgumentException();
+		if (inNext.getTimePeriod() != outCurr.getTimePeriod() + 1)
+			throw new IllegalArgumentException();
+		this.transportId = transportId;
+		this.inPrev = inPrev;
+		this.inCurr = inCurr;
+		this.inNext = inNext;
+		this.outCurr = outCurr;
+		this.rootKey = rootKey;
+		this.alice = alice;
+	}
+
+	public TransportId getTransportId() {
+		return transportId;
+	}
+
+	public IncomingKeys getPreviousIncomingKeys() {
+		return inPrev;
+	}
+
+	public IncomingKeys getCurrentIncomingKeys() {
+		return inCurr;
+	}
+
+	public IncomingKeys getNextIncomingKeys() {
+		return inNext;
+	}
+
+	public OutgoingKeys getCurrentOutgoingKeys() {
+		return outCurr;
+	}
+
+	public long getTimePeriod() {
+		return outCurr.getTimePeriod();
+	}
+
+	/**
+	 * 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

@@ -46,7 +46,14 @@ 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

@@ -0,0 +1,75 @@
+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

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.util;
 
+import java.io.File;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -19,6 +20,7 @@ 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()}
@@ -33,4 +35,26 @@ 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

@@ -153,4 +153,13 @@ 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

@@ -5,9 +5,17 @@ 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;
@@ -29,10 +37,10 @@ import java.util.Random;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import static java.util.Arrays.asList;
-import static org.briarproject.bramble.api.contact.PendingContactState.WAITING_FOR_CONNECTION;
+import static org.briarproject.bramble.api.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;
@@ -99,27 +107,46 @@ public class TestUtils {
 		return new SecretKey(getRandomBytes(SecretKey.LENGTH));
 	}
 
-	public static LocalAuthor getLocalAuthor() {
+	public static PublicKey getSignaturePublicKey() {
-		return getLocalAuthor(1 + random.nextInt(MAX_AUTHOR_NAME_LENGTH));
+		byte[] key = getRandomBytes(MAX_SIGNATURE_PUBLIC_KEY_BYTES);
+		return new SignaturePublicKey(key);
 	}
 
-	public static LocalAuthor getLocalAuthor(int nameLength) {
+	public static PrivateKey getSignaturePrivateKey() {
-		AuthorId id = new AuthorId(getRandomId());
+		return new SignaturePrivateKey(getRandomBytes(123));
-		String name = getRandomString(nameLength);
+	}
-		byte[] publicKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
+
-		byte[] privateKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
+	public static PublicKey getAgreementPublicKey() {
-		return new LocalAuthor(id, FORMAT_VERSION, name, publicKey, privateKey,
+		byte[] key = getRandomBytes(MAX_AGREEMENT_PUBLIC_KEY_BYTES);
+		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 Author getAuthor() {
+	public static LocalAuthor getLocalAuthor() {
-		return getAuthor(1 + random.nextInt(MAX_AUTHOR_NAME_LENGTH));
+		AuthorId id = new AuthorId(getRandomId());
+		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(int nameLength) {
+	public static Author getAuthor() {
 		AuthorId id = new AuthorId(getRandomId());
+		int nameLength = 1 + random.nextInt(MAX_AUTHOR_NAME_LENGTH);
 		String name = getRandomString(nameLength);
-		byte[] publicKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
+		PublicKey publicKey = getSignaturePublicKey();
 		return new Author(id, FORMAT_VERSION, name, publicKey);
 	}
 
@@ -152,10 +179,12 @@ public class TestUtils {
 
 	public static PendingContact getPendingContact(int nameLength) {
 		PendingContactId id = new PendingContactId(getRandomId());
-		byte[] publicKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
+		PublicKey publicKey = getAgreementPublicKey();
 		String alias = getRandomString(nameLength);
-		return new PendingContact(id, publicKey, alias, WAITING_FOR_CONNECTION,
+		int stateIndex =
-				timestamp);
+				random.nextInt(PendingContactState.values().length - 1);
+		PendingContactState state = PendingContactState.values()[stateIndex];
+		return new PendingContact(id, publicKey, alias, state, timestamp);
 	}
 
 	public static ContactId getContactId() {
@@ -176,7 +205,7 @@ public class TestUtils {
 			boolean verified) {
 		return new Contact(c, remote, local,
 				getRandomString(MAX_AUTHOR_NAME_LENGTH),
-				getRandomBytes(MAX_PUBLIC_KEY_LENGTH), verified);
+				getAgreementPublicKey(), verified);
 	}
 
 	public static double getMedian(Collection<? extends Number> samples) {

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:2.19:dagger-2.19.jar:514b6f1e0727c6572e1d65cb27e4ae668b7aeaeb93a29515182965265b609939',
+        'com.google.dagger:dagger:2.22.1:dagger-2.22.1.jar:329d4340f24c4f5717af016c097e90668bfea2a5376e6aa9964b01cef3fd241a',
         '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:2.19'
+	annotationProcessor 'com.google.dagger:dagger-compiler:2.22.1'
 
 	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:2.19'
+	testAnnotationProcessor 'com.google.dagger:dagger-compiler:2.22.1'
 
 	signature 'org.codehaus.mojo.signature:java16:1.1@signature'
 }

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");
-			LocalAuthor localAuthor = identityManager.createLocalAuthor(name);
+			Identity identity = identityManager.createIdentity(name);
-			identityManager.registerLocalAuthor(localAuthor);
+			identityManager.registerIdentity(identity);
 			SecretKey key = crypto.generateSecretKey();
 			if (!encryptAndStoreDatabaseKey(key, password)) return false;
 			databaseKey = key;

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

@@ -3,6 +3,9 @@ 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;
@@ -305,14 +308,15 @@ class ClientHelperImpl implements ClientHelper {
 	}
 
 	@Override
-	public byte[] sign(String label, BdfList toSign, byte[] privateKey)
+	public byte[] sign(String label, BdfList toSign, PrivateKey privateKey)
 			throws FormatException, GeneralSecurityException {
 		return crypto.sign(label, toByteArray(toSign), privateKey);
 	}
 
 	@Override
 	public void verifySignature(byte[] signature, String label, BdfList signed,
-			byte[] publicKey) throws FormatException, GeneralSecurityException {
+			PublicKey publicKey)
+			throws FormatException, GeneralSecurityException {
 		if (!crypto.verifySignature(signature, label, toByteArray(signed),
 				publicKey)) {
 			throw new GeneralSecurityException("Invalid signature");
@@ -327,11 +331,29 @@ class ClientHelperImpl implements ClientHelper {
 		if (formatVersion != FORMAT_VERSION) throw new FormatException();
 		String name = author.getString(1);
 		checkLength(name, 1, MAX_AUTHOR_NAME_LENGTH);
-		byte[] publicKey = author.getRaw(2);
+		byte[] publicKeyBytes = author.getRaw(2);
-		checkLength(publicKey, 1, MAX_PUBLIC_KEY_LENGTH);
+		checkLength(publicKeyBytes, 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/ContactManagerImpl.java

@@ -1,5 +1,6 @@
 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;
@@ -20,45 +21,42 @@ import org.briarproject.bramble.api.transport.KeyManager;
 
 import java.util.Collection;
 import java.util.List;
-import java.util.Random;
 import java.util.concurrent.CopyOnWriteArrayList;
-import java.util.regex.Pattern;
 
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 import javax.inject.Inject;
 
-import static java.util.Collections.emptyList;
+import static org.briarproject.bramble.api.contact.HandshakeLinkConstants.BASE32_LINK_BYTES;
-import static org.briarproject.bramble.api.contact.PendingContactState.WAITING_FOR_CONNECTION;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
-import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorInfo.Status.OURSELVES;
 import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNKNOWN;
 import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNVERIFIED;
 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(LINK_LENGTH);
+			"briar://" + getRandomBase32String(BASE32_LINK_BYTES);
-	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<>();
 	}
 
@@ -72,7 +70,8 @@ class ContactManagerImpl implements ContactManager {
 			SecretKey rootKey, long timestamp, boolean alice, boolean verified,
 			boolean active) throws DbException {
 		ContactId c = db.addContact(txn, remote, local, verified);
-		keyManager.addContact(txn, c, rootKey, timestamp, alice, active);
+		keyManager.addContactWithRotationKeys(txn, c, rootKey, timestamp,
+				alice, active);
 		Contact contact = db.getContact(txn, c);
 		for (ContactHook hook : hooks) hook.addingContact(txn, contact);
 		return c;
@@ -97,45 +96,28 @@ class ContactManagerImpl implements ContactManager {
 	}
 
 	@Override
-	public String getRemoteContactLink() {
+	public String getHandshakeLink() {
 		// TODO replace with real implementation
 		return REMOTE_CONTACT_LINK;
 	}
 
-	@SuppressWarnings("SameParameterValue")
+	@Override
-	private static String getRandomBase32String(int length) {
+	public PendingContact addPendingContact(String link, String alias)
-		Random random = new Random();
+			throws DbException, FormatException {
-		char[] c = new char[length];
+		PendingContact p =
-		for (int i = 0; i < length; i++) {
+				pendingContactFactory.createPendingContact(link, alias);
-			int character = random.nextInt(32);
+		db.transaction(false, txn -> db.addPendingContact(txn, p));
-			if (character < 26) c[i] = (char) ('a' + character);
+		return p;
-			else c[i] = (char) ('2' + (character - 26));
-		}
-		return new String(c);
 	}
 
 	@Override
-	public boolean isValidRemoteContactLink(String link) {
+	public Collection<PendingContact> getPendingContacts() throws DbException {
-		return LINK_REGEX.matcher(link).matches();
+		return db.transactionWithResult(true, db::getPendingContacts);
 	}
 
 	@Override
-	public PendingContact addRemoteContactRequest(String link, String alias) {
+	public void removePendingContact(PendingContactId p) throws DbException {
-		// TODO replace with real implementation
+		db.transaction(false, txn -> db.removePendingContact(txn, p));
-		PendingContactId id = new PendingContactId(link.getBytes());
-		return new PendingContact(id, new byte[MAX_PUBLIC_KEY_LENGTH], alias,
-				WAITING_FOR_CONNECTION, System.currentTimeMillis());
-	}
-
-	@Override
-	public Collection<PendingContact> getPendingContacts() {
-		// TODO replace with real implementation
-		return emptyList();
-	}
-
-	@Override
-	public void removePendingContact(PendingContact pendingContact) {
-		// TODO replace with real implementation
 	}
 
 	@Override

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

@@ -28,4 +28,10 @@ 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

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

@@ -0,0 +1,70 @@
+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/AgreementKeyParser.java

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

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

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

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

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

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

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

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

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

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

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

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

@@ -17,6 +17,7 @@ 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 {
@@ -39,7 +40,7 @@ class EdSignature implements Signature {
 
 	@Override
 	public void initSign(PrivateKey k) throws GeneralSecurityException {
-		if (!(k instanceof EdPrivateKey))
+		if (!k.getKeyType().equals(KEY_TYPE_SIGNATURE))
 			throw new IllegalArgumentException();
 		EdDSAPrivateKey privateKey = new EdDSAPrivateKey(
 				new EdDSAPrivateKeySpec(k.getEncoded(), CURVE_SPEC));
@@ -48,7 +49,7 @@ class EdSignature implements Signature {
 
 	@Override
 	public void initVerify(PublicKey k) throws GeneralSecurityException {
-		if (!(k instanceof EdPublicKey))
+		if (!k.getKeyType().equals(KEY_TYPE_SIGNATURE))
 			throw new IllegalArgumentException();
 		EdDSAPublicKey publicKey = new EdDSAPublicKey(
 				new EdDSAPublicKeySpec(k.getEncoded(), CURVE_SPEC));

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

@@ -49,6 +49,7 @@ 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;
@@ -69,7 +70,7 @@ public class MessageEncrypter {
 	MessageEncrypter(SecureRandom random) {
 		generator = new ECKeyPairGenerator();
 		generator.init(new ECKeyGenerationParameters(PARAMETERS, random));
-		parser = new Sec1KeyParser(PARAMETERS, MESSAGE_KEY_BITS);
+		parser = new Sec1KeyParser(KEY_TYPE, PARAMETERS, MESSAGE_KEY_BITS);
 		KeyEncoder encoder = new PublicKeyEncoder();
 		ephemeralGenerator = new EphemeralKeyPairGenerator(generator, encoder);
 		ephemeralParser = new PublicKeyParser(PARAMETERS);
@@ -80,11 +81,11 @@ public class MessageEncrypter {
 		// Return a wrapper that uses the SEC 1 encoding
 		ECPublicKeyParameters ecPublicKey =
 				(ECPublicKeyParameters) keyPair.getPublic();
-		PublicKey publicKey = new Sec1PublicKey(ecPublicKey);
+		PublicKey publicKey = new Sec1PublicKey(KEY_TYPE, ecPublicKey);
 		ECPrivateKeyParameters ecPrivateKey =
 				(ECPrivateKeyParameters) keyPair.getPrivate();
 		PrivateKey privateKey =
-				new Sec1PrivateKey(ecPrivateKey, MESSAGE_KEY_BITS);
+				new Sec1PrivateKey(KEY_TYPE, ecPrivateKey, MESSAGE_KEY_BITS);
 		return new KeyPair(publicKey, privateKey);
 	}
 

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

@@ -31,11 +31,13 @@ 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(ECDomainParameters params, int keyBits) {
+	Sec1KeyParser(String keyType, ECDomainParameters params, int keyBits) {
+		this.keyType = keyType;
 		this.params = params;
 		this.keyBits = keyBits;
 		modulus = ((ECCurve.Fp) params.getCurve()).getQ();
@@ -80,7 +82,7 @@ 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(k);
+		PublicKey p = new Sec1PublicKey(keyType, k);
 		logDuration(LOG, "Parsing public key", start);
 		return p;
 	}
@@ -97,7 +99,7 @@ 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(k, keyBits);
+		PrivateKey p = new Sec1PrivateKey(keyType, k, keyBits);
 		logDuration(LOG, "Parsing private key", start);
 		return p;
 	}

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

@@ -10,14 +10,21 @@ import javax.annotation.concurrent.Immutable;
 @NotNullByDefault
 class Sec1PrivateKey implements PrivateKey {
 
+	private final String keyType;
 	private final ECPrivateKeyParameters key;
 	private final int bytesPerInt;
 
-	Sec1PrivateKey(ECPrivateKeyParameters key, int keyBits) {
+	Sec1PrivateKey(String keyType, 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

@@ -15,12 +15,19 @@ import javax.annotation.concurrent.Immutable;
 @NotNullByDefault
 class Sec1PublicKey implements PublicKey {
 
+	private final String keyType;
 	private final ECPublicKeyParameters key;
 
-	Sec1PublicKey(ECPublicKeyParameters key) {
+	Sec1PublicKey(String keyType, 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/SignatureKeyParser.java

@@ -3,24 +3,29 @@ 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 EdKeyParser implements KeyParser {
+class SignatureKeyParser implements KeyParser {
 
 	@Override
 	public PublicKey parsePublicKey(byte[] encodedKey)
 			throws GeneralSecurityException {
 		if (encodedKey.length != 32) throw new GeneralSecurityException();
-		return new EdPublicKey(encodedKey);
+		return new SignaturePublicKey(encodedKey);
 	}
 
 	@Override
 	public PrivateKey parsePrivateKey(byte[] encodedKey)
 			throws GeneralSecurityException {
 		if (encodedKey.length != 32) throw new GeneralSecurityException();
-		return new EdPrivateKey(encodedKey);
+		return new SignaturePrivateKey(encodedKey);
 	}
 }

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

@@ -4,7 +4,6 @@ import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.crypto.TransportCrypto;
 import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.transport.HandshakeKeys;
 import org.briarproject.bramble.api.transport.IncomingKeys;
 import org.briarproject.bramble.api.transport.OutgoingKeys;
 import org.briarproject.bramble.api.transport.TransportKeys;
@@ -42,7 +41,7 @@ class TransportCryptoImpl implements TransportCrypto {
 	}
 
 	@Override
-	public TransportKeys deriveTransportKeys(TransportId t,
+	public TransportKeys deriveRotationKeys(TransportId t,
 			SecretKey rootKey, long timePeriod, boolean weAreAlice,
 			boolean active) {
 		// Keys for the previous period are derived from the root key
@@ -70,31 +69,6 @@ class TransportCryptoImpl implements TransportCrypto {
 		return new TransportKeys(t, inPrev, inCurr, inNext, outCurr);
 	}
 
-	@Override
-	public TransportKeys rotateTransportKeys(TransportKeys k, long timePeriod) {
-		if (k.getTimePeriod() >= timePeriod) return k;
-		IncomingKeys inPrev = k.getPreviousIncomingKeys();
-		IncomingKeys inCurr = k.getCurrentIncomingKeys();
-		IncomingKeys inNext = k.getNextIncomingKeys();
-		OutgoingKeys outCurr = k.getCurrentOutgoingKeys();
-		long startPeriod = outCurr.getTimePeriod();
-		boolean active = outCurr.isActive();
-		// Rotate the keys
-		for (long p = startPeriod + 1; p <= timePeriod; p++) {
-			inPrev = inCurr;
-			inCurr = inNext;
-			SecretKey inNextTag = rotateKey(inNext.getTagKey(), p + 1);
-			SecretKey inNextHeader = rotateKey(inNext.getHeaderKey(), p + 1);
-			inNext = new IncomingKeys(inNextTag, inNextHeader, p + 1);
-			SecretKey outCurrTag = rotateKey(outCurr.getTagKey(), p);
-			SecretKey outCurrHeader = rotateKey(outCurr.getHeaderKey(), p);
-			outCurr = new OutgoingKeys(outCurrTag, outCurrHeader, p, active);
-		}
-		// Collect and return the keys
-		return new TransportKeys(k.getTransportId(), inPrev, inCurr, inNext,
-				outCurr);
-	}
-
 	private SecretKey rotateKey(SecretKey k, long timePeriod) {
 		byte[] period = new byte[INT_64_BYTES];
 		writeUint64(timePeriod, period, 0);
@@ -117,7 +91,7 @@ class TransportCryptoImpl implements TransportCrypto {
 	}
 
 	@Override
-	public HandshakeKeys deriveHandshakeKeys(TransportId t, SecretKey rootKey,
+	public TransportKeys deriveHandshakeKeys(TransportId t, SecretKey rootKey,
 			long timePeriod, boolean weAreAlice) {
 		if (timePeriod < 1) throw new IllegalArgumentException();
 		IncomingKeys inPrev = deriveIncomingHandshakeKeys(t, rootKey,
@@ -128,7 +102,7 @@ class TransportCryptoImpl implements TransportCrypto {
 				weAreAlice, timePeriod + 1);
 		OutgoingKeys outCurr = deriveOutgoingHandshakeKeys(t, rootKey,
 				weAreAlice, timePeriod);
-		return new HandshakeKeys(t, inPrev, inCurr, inNext, outCurr, rootKey,
+		return new TransportKeys(t, inPrev, inCurr, inNext, outCurr, rootKey,
 				weAreAlice);
 	}
 
@@ -171,7 +145,13 @@ class TransportCryptoImpl implements TransportCrypto {
 	}
 
 	@Override
-	public HandshakeKeys updateHandshakeKeys(HandshakeKeys k, long timePeriod) {
+	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();
@@ -188,7 +168,7 @@ class TransportCryptoImpl implements TransportCrypto {
 					weAreAlice, timePeriod + 1);
 			OutgoingKeys outCurr = deriveOutgoingHandshakeKeys(t, rootKey,
 					weAreAlice, timePeriod);
-			return new HandshakeKeys(t, inPrev, inCurr, inNext, outCurr,
+			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
@@ -200,7 +180,7 @@ class TransportCryptoImpl implements TransportCrypto {
 					weAreAlice, timePeriod + 1);
 			OutgoingKeys outCurr = deriveOutgoingHandshakeKeys(t, rootKey,
 					weAreAlice, timePeriod);
-			return new HandshakeKeys(t, inPrev, inCurr, inNext, outCurr,
+			return new TransportKeys(t, inPrev, inCurr, inNext, outCurr,
 					rootKey, weAreAlice);
 		} else {
 			// The keys are more than two periods old - derive fresh keys
@@ -208,6 +188,30 @@ class TransportCryptoImpl implements TransportCrypto {
 		}
 	}
 
+	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();
+		boolean active = outCurr.isActive();
+		// Rotate the keys
+		for (long p = startPeriod + 1; p <= timePeriod; p++) {
+			inPrev = inCurr;
+			inCurr = inNext;
+			SecretKey inNextTag = rotateKey(inNext.getTagKey(), p + 1);
+			SecretKey inNextHeader = rotateKey(inNext.getHeaderKey(), p + 1);
+			inNext = new IncomingKeys(inNextTag, inNextHeader, p + 1);
+			SecretKey outCurrTag = rotateKey(outCurr.getTagKey(), p);
+			SecretKey outCurrHeader = rotateKey(outCurr.getHeaderKey(), p);
+			outCurr = new OutgoingKeys(outCurrTag, outCurrHeader, p, active);
+		}
+		// Collect and return the keys
+		return new TransportKeys(k.getTransportId(), inPrev, inCurr, inNext,
+				outCurr);
+	}
+
 	@Override
 	public void encodeTag(byte[] tag, SecretKey tagKey, int protocolVersion,
 			long streamNumber) {

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

@@ -5,6 +5,8 @@ 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.PrivateKey;
+import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.DataTooNewException;
 import org.briarproject.bramble.api.db.DataTooOldException;
@@ -15,7 +17,7 @@ import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.MigrationListener;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
-import org.briarproject.bramble.api.identity.LocalAuthor;
+import org.briarproject.bramble.api.identity.Identity;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.settings.Settings;
@@ -27,11 +29,8 @@ import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.MessageStatus;
 import org.briarproject.bramble.api.sync.validation.MessageState;
-import org.briarproject.bramble.api.transport.HandshakeKeySet;
+import org.briarproject.bramble.api.transport.KeySetId;
-import org.briarproject.bramble.api.transport.HandshakeKeySetId;
-import org.briarproject.bramble.api.transport.HandshakeKeys;
 import org.briarproject.bramble.api.transport.TransportKeySet;
-import org.briarproject.bramble.api.transport.TransportKeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.util.Collection;
@@ -106,23 +105,9 @@ interface Database<T> {
 			throws DbException;
 
 	/**
-	 * Stores the given handshake keys for the given contact and returns a
+	 * Stores an identity.
-	 * key set ID.
 	 */
-	HandshakeKeySetId addHandshakeKeys(T txn, ContactId c, HandshakeKeys k)
+	void addIdentity(T txn, Identity i) throws DbException;
-			throws DbException;
-
-	/**
-	 * Stores the given handshake keys for the given pending contact and
-	 * returns a key set ID.
-	 */
-	HandshakeKeySetId addHandshakeKeys(T txn, PendingContactId p,
-			HandshakeKeys k) throws DbException;
-
-	/**
-	 * Stores a local pseudonym.
-	 */
-	void addLocalAuthor(T txn, LocalAuthor a) throws DbException;
 
 	/**
 	 * Stores a message.
@@ -160,7 +145,14 @@ interface Database<T> {
 	 * Stores the given transport keys for the given contact and returns a
 	 * key set ID.
 	 */
-	TransportKeySetId addTransportKeys(T txn, ContactId c, TransportKeys k)
+	KeySetId addTransportKeys(T txn, ContactId c, TransportKeys k)
+			throws DbException;
+
+	/**
+	 * Stores the given transport keys for the given pending contact and
+	 * returns a key set ID.
+	 */
+	KeySetId addTransportKeys(T txn, PendingContactId p, TransportKeys k)
 			throws DbException;
 
 	/**
@@ -187,11 +179,12 @@ interface Database<T> {
 	boolean containsGroup(T txn, GroupId g) throws DbException;
 
 	/**
-	 * Returns true if the database contains the given local pseudonym.
+	 * Returns true if the database contains an identity for the given
+	 * pseudonym.
 	 * <p/>
 	 * Read-only.
 	 */
-	boolean containsLocalAuthor(T txn, AuthorId a) throws DbException;
+	boolean containsIdentity(T txn, AuthorId a) throws DbException;
 
 	/**
 	 * Returns true if the database contains the given message.
@@ -272,7 +265,7 @@ interface Database<T> {
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<ContactId> getContacts(T txn, AuthorId a) throws DbException;
+	Collection<ContactId> getContacts(T txn, AuthorId local) throws DbException;
 
 	/**
 	 * Returns the group with the given ID.
@@ -315,26 +308,18 @@ interface Database<T> {
 			throws DbException;
 
 	/**
-	 * Returns all handshake keys for the given transport.
+	 * Returns the identity for local pseudonym with the given ID.
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<HandshakeKeySet> getHandshakeKeys(T txn, TransportId t)
+	Identity getIdentity(T txn, AuthorId a) throws DbException;
-			throws DbException;
 
 	/**
-	 * Returns the local pseudonym with the given ID.
+	 * Returns the identities for all local pseudonyms.
 	 * <p/>
 	 * Read-only.
 	 */
-	LocalAuthor getLocalAuthor(T txn, AuthorId a) throws DbException;
+	Collection<Identity> getIdentities(T txn) throws DbException;
-
-	/**
-	 * Returns all local pseudonyms.
-	 * <p/>
-	 * Read-only.
-	 */
-	Collection<LocalAuthor> getLocalAuthors(T txn) throws DbException;
 
 	/**
 	 * Returns the message with the given ID.
@@ -544,16 +529,10 @@ interface Database<T> {
 	Collection<TransportKeySet> getTransportKeys(T txn, TransportId t)
 			throws DbException;
 
-	/**
-	 * Increments the outgoing stream counter for the given handshake keys.
-	 */
-	void incrementStreamCounter(T txn, TransportId t, HandshakeKeySetId k)
-			throws DbException;
-
 	/**
 	 * Increments the outgoing stream counter for the given transport keys.
 	 */
-	void incrementStreamCounter(T txn, TransportId t, TransportKeySetId k)
+	void incrementStreamCounter(T txn, TransportId t, KeySetId k)
 			throws DbException;
 
 	/**
@@ -623,15 +602,9 @@ interface Database<T> {
 			throws DbException;
 
 	/**
-	 * Removes the given handshake keys from the database.
+	 * Removes an identity (and all associated state) from the database.
 	 */
-	void removeHandshakeKeys(T txn, TransportId t, HandshakeKeySetId k)
+	void removeIdentity(T txn, AuthorId a) throws DbException;
-			throws DbException;
-
-	/**
-	 * Removes a local pseudonym (and all associated state) from the database.
-	 */
-	void removeLocalAuthor(T txn, AuthorId a) throws DbException;
 
 	/**
 	 * Removes a message (and all associated state) from the database.
@@ -658,8 +631,7 @@ interface Database<T> {
 	/**
 	 * Removes the given transport keys from the database.
 	 */
-	void removeTransportKeys(T txn, TransportId t, TransportKeySetId k)
+	void removeTransportKeys(T txn, TransportId t, KeySetId k) throws DbException;
-			throws DbException;
 
 	/**
 	 * Resets the transmission count and expiry time of the given message with
@@ -685,6 +657,12 @@ interface Database<T> {
 	void setGroupVisibility(T txn, ContactId c, GroupId g, boolean shared)
 			throws DbException;
 
+	/**
+	 * Sets the handshake key pair for the identity with the given ID.
+	 */
+	void setHandshakeKeyPair(T txn, AuthorId local, PublicKey publicKey,
+			PrivateKey privateKey) throws DbException;
+
 	/**
 	 * Marks the given message as shared.
 	 */
@@ -703,23 +681,16 @@ interface Database<T> {
 			PendingContactState state) throws DbException;
 
 	/**
-	 * Sets the reordering window for the given transport key set in the given
+	 * Sets the reordering window for the given transport keys in the given
 	 * time period.
 	 */
-	void setReorderingWindow(T txn, TransportKeySetId k, TransportId t,
+	void setReorderingWindow(T txn, KeySetId k, TransportId t,
-			long timePeriod, long base, byte[] bitmap) throws DbException;
-
-	/**
-	 * Sets the reordering window for the given handshake key set in the given
-	 * time period.
-	 */
-	void setReorderingWindow(T txn, HandshakeKeySetId k, TransportId t,
 			long timePeriod, long base, byte[] bitmap) throws DbException;
 
 	/**
 	 * Marks the given transport keys as usable for outgoing streams.
 	 */
-	void setTransportKeysActive(T txn, TransportId t, TransportKeySetId k)
+	void setTransportKeysActive(T txn, TransportId t, KeySetId k)
 			throws DbException;
 
 	/**
@@ -731,12 +702,7 @@ interface Database<T> {
 			throws DbException;
 
 	/**
-	 * Updates the given handshake keys.
+	 * Stores the given transport keys, deleting any keys they have replaced.
-	 */
-	void updateHandshakeKeys(T txn, HandshakeKeySet ks) throws DbException;
-
-	/**
-	 * Updates the given transport keys following key rotation.
 	 */
 	void updateTransportKeys(T txn, TransportKeySet ks) throws DbException;
 }

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

@@ -7,6 +7,10 @@ import org.briarproject.bramble.api.contact.PendingContactId;
 import org.briarproject.bramble.api.contact.event.ContactAddedEvent;
 import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
 import org.briarproject.bramble.api.contact.event.ContactVerifiedEvent;
+import org.briarproject.bramble.api.contact.event.PendingContactRemovedEvent;
+import org.briarproject.bramble.api.contact.event.PendingContactStateChangedEvent;
+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.db.CommitAction;
 import org.briarproject.bramble.api.db.CommitAction.Visitor;
@@ -20,7 +24,7 @@ import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.MigrationListener;
 import org.briarproject.bramble.api.db.NoSuchContactException;
 import org.briarproject.bramble.api.db.NoSuchGroupException;
-import org.briarproject.bramble.api.db.NoSuchLocalAuthorException;
+import org.briarproject.bramble.api.db.NoSuchIdentityException;
 import org.briarproject.bramble.api.db.NoSuchMessageException;
 import org.briarproject.bramble.api.db.NoSuchPendingContactException;
 import org.briarproject.bramble.api.db.NoSuchTransportException;
@@ -32,9 +36,9 @@ import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.event.EventExecutor;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
-import org.briarproject.bramble.api.identity.LocalAuthor;
+import org.briarproject.bramble.api.identity.Identity;
-import org.briarproject.bramble.api.identity.event.LocalAuthorAddedEvent;
+import org.briarproject.bramble.api.identity.event.IdentityAddedEvent;
-import org.briarproject.bramble.api.identity.event.LocalAuthorRemovedEvent;
+import org.briarproject.bramble.api.identity.event.IdentityRemovedEvent;
 import org.briarproject.bramble.api.lifecycle.ShutdownManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
@@ -62,11 +66,8 @@ import org.briarproject.bramble.api.sync.event.MessageToRequestEvent;
 import org.briarproject.bramble.api.sync.event.MessagesAckedEvent;
 import org.briarproject.bramble.api.sync.event.MessagesSentEvent;
 import org.briarproject.bramble.api.sync.validation.MessageState;
-import org.briarproject.bramble.api.transport.HandshakeKeySet;
+import org.briarproject.bramble.api.transport.KeySetId;
-import org.briarproject.bramble.api.transport.HandshakeKeySetId;
-import org.briarproject.bramble.api.transport.HandshakeKeys;
 import org.briarproject.bramble.api.transport.TransportKeySet;
-import org.briarproject.bramble.api.transport.TransportKeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.util.ArrayList;
@@ -237,9 +238,9 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
-		if (!db.containsLocalAuthor(txn, local))
+		if (!db.containsIdentity(txn, local))
-			throw new NoSuchLocalAuthorException();
+			throw new NoSuchIdentityException();
-		if (db.containsLocalAuthor(txn, remote.getId()))
+		if (db.containsIdentity(txn, remote.getId()))
 			throw new ContactExistsException();
 		if (db.containsContact(txn, remote.getId(), local))
 			throw new ContactExistsException();
@@ -259,37 +260,13 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public HandshakeKeySetId addHandshakeKeys(Transaction transaction,
+	public void addIdentity(Transaction transaction, Identity i)
-			ContactId c, HandshakeKeys k) throws DbException {
-		if (transaction.isReadOnly()) throw new IllegalArgumentException();
-		T txn = unbox(transaction);
-		if (!db.containsContact(txn, c))
-			throw new NoSuchContactException();
-		if (!db.containsTransport(txn, k.getTransportId()))
-			throw new NoSuchTransportException();
-		return db.addHandshakeKeys(txn, c, k);
-	}
-
-	@Override
-	public HandshakeKeySetId addHandshakeKeys(Transaction transaction,
-			PendingContactId p, HandshakeKeys k) throws DbException {
-		if (transaction.isReadOnly()) throw new IllegalArgumentException();
-		T txn = unbox(transaction);
-		if (!db.containsPendingContact(txn, p))
-			throw new NoSuchPendingContactException();
-		if (!db.containsTransport(txn, k.getTransportId()))
-			throw new NoSuchTransportException();
-		return db.addHandshakeKeys(txn, p, k);
-	}
-
-	@Override
-	public void addLocalAuthor(Transaction transaction, LocalAuthor a)
 			throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
-		if (!db.containsLocalAuthor(txn, a.getId())) {
+		if (!db.containsIdentity(txn, i.getId())) {
-			db.addLocalAuthor(txn, a);
+			db.addIdentity(txn, i);
-			transaction.attach(new LocalAuthorAddedEvent(a.getId()));
+			transaction.attach(new IdentityAddedEvent(i.getId()));
 		}
 	}
 
@@ -318,6 +295,8 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		if (db.containsPendingContact(txn, p.getId()))
 			throw new PendingContactExistsException();
 		db.addPendingContact(txn, p);
+		transaction.attach(new PendingContactStateChangedEvent(p.getId(),
+				p.getState()));
 	}
 
 	@Override
@@ -330,8 +309,8 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public TransportKeySetId addTransportKeys(Transaction transaction,
+	public KeySetId addTransportKeys(Transaction transaction, ContactId c,
-			ContactId c, TransportKeys k) throws DbException {
+			TransportKeys k) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
 		if (!db.containsContact(txn, c))
@@ -341,12 +320,24 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.addTransportKeys(txn, c, k);
 	}
 
+	@Override
+	public KeySetId addTransportKeys(Transaction transaction,
+			PendingContactId p, TransportKeys k) throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsPendingContact(txn, p))
+			throw new NoSuchPendingContactException();
+		if (!db.containsTransport(txn, k.getTransportId()))
+			throw new NoSuchTransportException();
+		return db.addTransportKeys(txn, p, k);
+	}
+
 	@Override
 	public boolean containsContact(Transaction transaction, AuthorId remote,
 			AuthorId local) throws DbException {
 		T txn = unbox(transaction);
-		if (!db.containsLocalAuthor(txn, local))
+		if (!db.containsIdentity(txn, local))
-			throw new NoSuchLocalAuthorException();
+			throw new NoSuchIdentityException();
 		return db.containsContact(txn, remote, local);
 	}
 
@@ -358,10 +349,10 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public boolean containsLocalAuthor(Transaction transaction, AuthorId local)
+	public boolean containsIdentity(Transaction transaction, AuthorId a)
 			throws DbException {
 		T txn = unbox(transaction);
-		return db.containsLocalAuthor(txn, local);
+		return db.containsIdentity(txn, a);
 	}
 
 	@Override
@@ -503,11 +494,11 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 
 	@Override
 	public Collection<ContactId> getContacts(Transaction transaction,
-			AuthorId a) throws DbException {
+			AuthorId local) throws DbException {
 		T txn = unbox(transaction);
-		if (!db.containsLocalAuthor(txn, a))
+		if (!db.containsIdentity(txn, local))
-			throw new NoSuchLocalAuthorException();
+			throw new NoSuchIdentityException();
-		return db.getContacts(txn, a);
+		return db.getContacts(txn, local);
 	}
 
 	@Override
@@ -545,28 +536,19 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public Collection<HandshakeKeySet> getHandshakeKeys(Transaction transaction,
+	public Identity getIdentity(Transaction transaction, AuthorId a)
-			TransportId t) throws DbException {
+			throws DbException {
 		T txn = unbox(transaction);
-		if (!db.containsTransport(txn, t))
+		if (!db.containsIdentity(txn, a))
-			throw new NoSuchTransportException();
+			throw new NoSuchIdentityException();
-		return db.getHandshakeKeys(txn, t);
+		return db.getIdentity(txn, a);
 	}
 
 	@Override
-	public LocalAuthor getLocalAuthor(Transaction transaction, AuthorId a)
+	public Collection<Identity> getIdentities(Transaction transaction)
 			throws DbException {
 		T txn = unbox(transaction);
-		if (!db.containsLocalAuthor(txn, a))
+		return db.getIdentities(txn);
-			throw new NoSuchLocalAuthorException();
-		return db.getLocalAuthor(txn, a);
-	}
-
-	@Override
-	public Collection<LocalAuthor> getLocalAuthors(Transaction transaction)
-			throws DbException {
-		T txn = unbox(transaction);
-		return db.getLocalAuthors(txn);
 	}
 
 	@Override
@@ -735,17 +717,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 
 	@Override
 	public void incrementStreamCounter(Transaction transaction, TransportId t,
-			HandshakeKeySetId k) throws DbException {
+			KeySetId k) throws DbException {
-		if (transaction.isReadOnly()) throw new IllegalArgumentException();
-		T txn = unbox(transaction);
-		if (!db.containsTransport(txn, t))
-			throw new NoSuchTransportException();
-		db.incrementStreamCounter(txn, t, k);
-	}
-
-	@Override
-	public void incrementStreamCounter(Transaction transaction, TransportId t,
-			TransportKeySetId k) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
 		if (!db.containsTransport(txn, t))
@@ -895,24 +867,14 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public void removeHandshakeKeys(Transaction transaction,
+	public void removeIdentity(Transaction transaction, AuthorId a)
-			TransportId t, HandshakeKeySetId k) throws DbException {
-		if (transaction.isReadOnly()) throw new IllegalArgumentException();
-		T txn = unbox(transaction);
-		if (!db.containsTransport(txn, t))
-			throw new NoSuchTransportException();
-		db.removeHandshakeKeys(txn, t, k);
-	}
-
-	@Override
-	public void removeLocalAuthor(Transaction transaction, AuthorId a)
 			throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
-		if (!db.containsLocalAuthor(txn, a))
+		if (!db.containsIdentity(txn, a))
-			throw new NoSuchLocalAuthorException();
+			throw new NoSuchIdentityException();
-		db.removeLocalAuthor(txn, a);
+		db.removeIdentity(txn, a);
-		transaction.attach(new LocalAuthorRemovedEvent(a));
+		transaction.attach(new IdentityRemovedEvent(a));
 	}
 
 	@Override
@@ -934,6 +896,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		if (!db.containsPendingContact(txn, p))
 			throw new NoSuchPendingContactException();
 		db.removePendingContact(txn, p);
+		transaction.attach(new PendingContactRemovedEvent(p));
 	}
 
 	@Override
@@ -947,8 +910,8 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public void removeTransportKeys(Transaction transaction,
+	public void removeTransportKeys(Transaction transaction, TransportId t,
-			TransportId t, TransportKeySetId k) throws DbException {
+			KeySetId k) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
 		if (!db.containsTransport(txn, t))
@@ -1036,20 +999,19 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public void setReorderingWindow(Transaction transaction,
+	public void setHandshakeKeyPair(Transaction transaction, AuthorId local,
-			TransportKeySetId k, TransportId t, long timePeriod, long base,
+			PublicKey publicKey, PrivateKey privateKey) throws DbException {
-			byte[] bitmap) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
-		if (!db.containsTransport(txn, t))
+		if (!db.containsIdentity(txn, local))
-			throw new NoSuchTransportException();
+			throw new NoSuchIdentityException();
-		db.setReorderingWindow(txn, k, t, timePeriod, base, bitmap);
+		db.setHandshakeKeyPair(txn, local, publicKey, privateKey);
 	}
 
 	@Override
-	public void setReorderingWindow(Transaction transaction,
+	public void setReorderingWindow(Transaction transaction, KeySetId k,
-			HandshakeKeySetId k, TransportId t, long timePeriod, long base,
+			TransportId t, long timePeriod, long base, byte[] bitmap)
-			byte[] bitmap) throws DbException {
+			throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
 		if (!db.containsTransport(txn, t))
@@ -1059,7 +1021,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 
 	@Override
 	public void setTransportKeysActive(Transaction transaction, TransportId t,
-			TransportKeySetId k) throws DbException {
+			KeySetId k) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
 		if (!db.containsTransport(txn, t))
@@ -1067,18 +1029,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		db.setTransportKeysActive(txn, t, k);
 	}
 
-	@Override
-	public void updateHandshakeKeys(Transaction transaction,
-			Collection<HandshakeKeySet> keys) throws DbException {
-		if (transaction.isReadOnly()) throw new IllegalArgumentException();
-		T txn = unbox(transaction);
-		for (HandshakeKeySet ks : keys) {
-			TransportId t = ks.getKeys().getTransportId();
-			if (db.containsTransport(txn, t))
-				db.updateHandshakeKeys(txn, ks);
-		}
-	}
-
 	@Override
 	public void updateTransportKeys(Transaction transaction,
 			Collection<TransportKeySet> keys) throws DbException {

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

@@ -20,9 +20,11 @@ import java.util.logging.Logger;
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 
+import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.db.JdbcUtils.tryToClose;
+import static org.briarproject.bramble.util.LogUtils.logFileOrDir;
 
 /**
  * Contains all the H2-specific code for the database.
@@ -61,8 +63,18 @@ class H2Database extends JdbcDatabase {
 	public boolean open(SecretKey key, @Nullable MigrationListener listener)
 			throws DbException {
 		this.key = key;
-		boolean reopen = !config.getDatabaseDirectory().mkdirs();
+		File dir = config.getDatabaseDirectory();
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Contents of account directory before opening DB:");
+			logFileOrDir(LOG, INFO, dir.getParentFile());
+		}
+		boolean reopen = !dir.mkdirs();
+		if (LOG.isLoggable(INFO)) LOG.info("Reopening DB: " + reopen);
 		super.open("org.h2.Driver", reopen, key, listener);
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Contents of account directory after opening DB:");
+			logFileOrDir(LOG, INFO, dir.getParentFile());
+		}
 		return reopen;
 	}
 

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

@@ -5,7 +5,13 @@ 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.db.DataTooNewException;
 import org.briarproject.bramble.api.db.DataTooOldException;
 import org.briarproject.bramble.api.db.DbClosedException;
@@ -15,6 +21,7 @@ import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.MigrationListener;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.identity.Identity;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
@@ -29,13 +36,10 @@ import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.MessageStatus;
 import org.briarproject.bramble.api.sync.validation.MessageState;
 import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.bramble.api.transport.HandshakeKeySet;
-import org.briarproject.bramble.api.transport.HandshakeKeySetId;
-import org.briarproject.bramble.api.transport.HandshakeKeys;
 import org.briarproject.bramble.api.transport.IncomingKeys;
+import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.OutgoingKeys;
 import org.briarproject.bramble.api.transport.TransportKeySet;
-import org.briarproject.bramble.api.transport.TransportKeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.sql.Connection;
@@ -61,11 +65,13 @@ import java.util.logging.Logger;
 import javax.annotation.Nullable;
 
 import static java.sql.Types.BINARY;
+import static java.sql.Types.BOOLEAN;
 import static java.sql.Types.INTEGER;
 import static java.sql.Types.VARCHAR;
 import static java.util.Arrays.asList;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.db.Metadata.REMOVE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
@@ -92,7 +98,7 @@ import static org.briarproject.bramble.util.LogUtils.now;
 abstract class JdbcDatabase implements Database<Connection> {
 
 	// Package access for testing
-	static final int CODE_SCHEMA_VERSION = 43;
+	static final int CODE_SCHEMA_VERSION = 44;
 
 	// Time period offsets for incoming transport keys
 	private static final int OFFSET_PREV = -1;
@@ -253,16 +259,28 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " maxLatency INT NOT NULL,"
 					+ " PRIMARY KEY (transportId))";
 
+	private static final String CREATE_PENDING_CONTACTS =
+			"CREATE TABLE pendingContacts"
+					+ " (pendingContactId _HASH NOT NULL,"
+					+ " publicKey _BINARY NOT NULL,"
+					+ " alias _STRING NOT NULL,"
+					+ " state INT NOT NULL,"
+					+ " timestamp BIGINT NOT NULL,"
+					+ " PRIMARY KEY (pendingContactId))";
+
 	private static final String CREATE_OUTGOING_KEYS =
 			"CREATE TABLE outgoingKeys"
 					+ " (transportId _STRING NOT NULL,"
 					+ " keySetId _COUNTER,"
 					+ " timePeriod BIGINT NOT NULL,"
-					+ " contactId INT NOT NULL,"
+					+ " contactId INT," // Null if contact is pending
+					+ " pendingContactId _HASH," // Null if not pending
 					+ " tagKey _SECRET NOT NULL,"
 					+ " headerKey _SECRET NOT NULL,"
 					+ " stream BIGINT NOT NULL,"
 					+ " active BOOLEAN NOT NULL,"
+					+ " rootKey _SECRET," // Null for rotation keys
+					+ " alice BOOLEAN," // Null for rotation keys
 					+ " PRIMARY KEY (transportId, keySetId),"
 					+ " FOREIGN KEY (transportId)"
 					+ " REFERENCES transports (transportId)"
@@ -270,6 +288,9 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " UNIQUE (keySetId),"
 					+ " FOREIGN KEY (contactId)"
 					+ " REFERENCES contacts (contactId)"
+					+ " ON DELETE CASCADE,"
+					+ " FOREIGN KEY (pendingContactId)"
+					+ " REFERENCES pendingContacts (pendingContactId)"
 					+ " ON DELETE CASCADE)";
 
 	private static final String CREATE_INCOMING_KEYS =
@@ -290,57 +311,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " REFERENCES outgoingKeys (keySetId)"
 					+ " ON DELETE CASCADE)";
 
-	private static final String CREATE_PENDING_CONTACTS =
-			"CREATE TABLE pendingContacts"
-					+ " (pendingContactId _HASH NOT NULL,"
-					+ " publicKey _BINARY NOT NULL,"
-					+ " alias _STRING NOT NULL,"
-					+ " state INT NOT NULL,"
-					+ " timestamp BIGINT NOT NULL,"
-					+ " PRIMARY KEY (pendingContactId))";
-
-	private static final String CREATE_OUTGOING_HANDSHAKE_KEYS =
-			"CREATE TABLE outgoingHandshakeKeys"
-					+ " (transportId _STRING NOT NULL,"
-					+ " keySetId _COUNTER,"
-					+ " timePeriod BIGINT NOT NULL,"
-					+ " contactId INT," // Null if contact is pending
-					+ " pendingContactId _HASH," // Null if not pending
-					+ " rootKey _SECRET NOT NULL,"
-					+ " alice BOOLEAN NOT NULL,"
-					+ " tagKey _SECRET NOT NULL,"
-					+ " headerKey _SECRET NOT NULL,"
-					+ " stream BIGINT NOT NULL,"
-					+ " PRIMARY KEY (transportId, keySetId),"
-					+ " FOREIGN KEY (transportId)"
-					+ " REFERENCES transports (transportId)"
-					+ " ON DELETE CASCADE,"
-					+ " UNIQUE (keySetId),"
-					+ " FOREIGN KEY (contactId)"
-					+ " REFERENCES contacts (contactId)"
-					+ " ON DELETE CASCADE,"
-					+ " FOREIGN KEY (pendingContactId)"
-					+ " REFERENCES pendingContacts (pendingContactId)"
-					+ " ON DELETE CASCADE)";
-
-	private static final String CREATE_INCOMING_HANDSHAKE_KEYS =
-			"CREATE TABLE incomingHandshakeKeys"
-					+ " (transportId _STRING NOT NULL,"
-					+ " keySetId INT NOT NULL,"
-					+ " timePeriod BIGINT NOT NULL,"
-					+ " tagKey _SECRET NOT NULL,"
-					+ " headerKey _SECRET NOT NULL,"
-					+ " base BIGINT NOT NULL,"
-					+ " bitmap _BINARY NOT NULL,"
-					+ " periodOffset INT NOT NULL,"
-					+ " PRIMARY KEY (transportId, keySetId, periodOffset),"
-					+ " FOREIGN KEY (transportId)"
-					+ " REFERENCES transports (transportId)"
-					+ " ON DELETE CASCADE,"
-					+ " FOREIGN KEY (keySetId)"
-					+ " REFERENCES outgoingHandshakeKeys (keySetId)"
-					+ " ON DELETE CASCADE)";
-
 	private static final String INDEX_CONTACTS_BY_AUTHOR_ID =
 			"CREATE INDEX IF NOT EXISTS contactsByAuthorId"
 					+ " ON contacts (authorId)";
@@ -366,7 +336,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " ON statuses (contactId, timestamp)";
 
 	private static final Logger LOG =
-			Logger.getLogger(JdbcDatabase.class.getName());
+			getLogger(JdbcDatabase.class.getName());
 
 	// Different database libraries use different names for certain types
 	private final MessageFactory messageFactory;
@@ -486,7 +456,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 				new Migration39_40(),
 				new Migration40_41(dbTypes),
 				new Migration41_42(dbTypes),
-				new Migration42_43(dbTypes)
+				new Migration42_43(dbTypes),
+				new Migration43_44(dbTypes)
 		);
 	}
 
@@ -534,13 +505,9 @@ abstract class JdbcDatabase implements Database<Connection> {
 			s.executeUpdate(dbTypes.replaceTypes(CREATE_OFFERS));
 			s.executeUpdate(dbTypes.replaceTypes(CREATE_STATUSES));
 			s.executeUpdate(dbTypes.replaceTypes(CREATE_TRANSPORTS));
+			s.executeUpdate(dbTypes.replaceTypes(CREATE_PENDING_CONTACTS));
 			s.executeUpdate(dbTypes.replaceTypes(CREATE_OUTGOING_KEYS));
 			s.executeUpdate(dbTypes.replaceTypes(CREATE_INCOMING_KEYS));
-			s.executeUpdate(dbTypes.replaceTypes(CREATE_PENDING_CONTACTS));
-			s.executeUpdate(dbTypes.replaceTypes(
-					CREATE_OUTGOING_HANDSHAKE_KEYS));
-			s.executeUpdate(dbTypes.replaceTypes(
-					CREATE_INCOMING_HANDSHAKE_KEYS));
 			s.close();
 		} catch (SQLException e) {
 			tryToClose(s, LOG, WARNING);
@@ -676,7 +643,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setBytes(1, remote.getId().getBytes());
 			ps.setInt(2, remote.getFormatVersion());
 			ps.setString(3, remote.getName());
-			ps.setBytes(4, remote.getPublicKey());
+			ps.setBytes(4, remote.getPublicKey().getEncoded());
 			ps.setBytes(5, local.getBytes());
 			ps.setBoolean(6, verified);
 			int affected = ps.executeUpdate();
@@ -777,105 +744,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public HandshakeKeySetId addHandshakeKeys(Connection txn, ContactId c,
+	public void addIdentity(Connection txn, Identity i) throws DbException {
-			HandshakeKeys k) throws DbException {
-		return addHandshakeKeys(txn, c, null, k);
-	}
-
-	@Override
-	public HandshakeKeySetId addHandshakeKeys(Connection txn,
-			PendingContactId p, HandshakeKeys k) throws DbException {
-		return addHandshakeKeys(txn, null, p, k);
-	}
-
-	private HandshakeKeySetId addHandshakeKeys(Connection txn,
-			@Nullable ContactId c, @Nullable PendingContactId p,
-			HandshakeKeys k) throws DbException {
-		PreparedStatement ps = null;
-		ResultSet rs = null;
-		try {
-			// Store the outgoing keys
-			String sql = "INSERT INTO outgoingHandshakeKeys (contactId,"
-					+ " pendingContactId, transportId, rootKey, alice,"
-					+ " timePeriod, tagKey, headerKey, stream)"
-					+ " VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)";
-			ps = txn.prepareStatement(sql);
-			if (c == null) ps.setNull(1, INTEGER);
-			else ps.setInt(1, c.getInt());
-			if (p == null) ps.setNull(2, BINARY);
-			else ps.setBytes(2, p.getBytes());
-			ps.setString(3, k.getTransportId().getString());
-			ps.setBytes(4, k.getRootKey().getBytes());
-			ps.setBoolean(5, k.isAlice());
-			OutgoingKeys outCurr = k.getCurrentOutgoingKeys();
-			ps.setLong(6, outCurr.getTimePeriod());
-			ps.setBytes(7, outCurr.getTagKey().getBytes());
-			ps.setBytes(8, outCurr.getHeaderKey().getBytes());
-			ps.setLong(9, outCurr.getStreamCounter());
-			int affected = ps.executeUpdate();
-			if (affected != 1) throw new DbStateException();
-			ps.close();
-			// Get the new (highest) key set ID
-			sql = "SELECT keySetId FROM outgoingHandshakeKeys"
-					+ " ORDER BY keySetId DESC LIMIT 1";
-			ps = txn.prepareStatement(sql);
-			rs = ps.executeQuery();
-			if (!rs.next()) throw new DbStateException();
-			HandshakeKeySetId keySetId = new HandshakeKeySetId(rs.getInt(1));
-			if (rs.next()) throw new DbStateException();
-			rs.close();
-			ps.close();
-			// Store the incoming keys
-			sql = "INSERT INTO incomingHandshakeKeys (keySetId, transportId,"
-					+ " timePeriod, tagKey, headerKey, base, bitmap,"
-					+ " periodOffset)"
-					+ " VALUES (?, ?, ?, ?, ?, ?, ?, ?)";
-			ps = txn.prepareStatement(sql);
-			ps.setInt(1, keySetId.getInt());
-			ps.setString(2, k.getTransportId().getString());
-			// Previous time period
-			IncomingKeys inPrev = k.getPreviousIncomingKeys();
-			ps.setLong(3, inPrev.getTimePeriod());
-			ps.setBytes(4, inPrev.getTagKey().getBytes());
-			ps.setBytes(5, inPrev.getHeaderKey().getBytes());
-			ps.setLong(6, inPrev.getWindowBase());
-			ps.setBytes(7, inPrev.getWindowBitmap());
-			ps.setInt(8, OFFSET_PREV);
-			ps.addBatch();
-			// Current time period
-			IncomingKeys inCurr = k.getCurrentIncomingKeys();
-			ps.setLong(3, inCurr.getTimePeriod());
-			ps.setBytes(4, inCurr.getTagKey().getBytes());
-			ps.setBytes(5, inCurr.getHeaderKey().getBytes());
-			ps.setLong(6, inCurr.getWindowBase());
-			ps.setBytes(7, inCurr.getWindowBitmap());
-			ps.setInt(8, OFFSET_CURR);
-			ps.addBatch();
-			// Next time period
-			IncomingKeys inNext = k.getNextIncomingKeys();
-			ps.setLong(3, inNext.getTimePeriod());
-			ps.setBytes(4, inNext.getTagKey().getBytes());
-			ps.setBytes(5, inNext.getHeaderKey().getBytes());
-			ps.setLong(6, inNext.getWindowBase());
-			ps.setBytes(7, inNext.getWindowBitmap());
-			ps.setInt(8, OFFSET_NEXT);
-			ps.addBatch();
-			int[] batchAffected = ps.executeBatch();
-			if (batchAffected.length != 3) throw new DbStateException();
-			for (int rows : batchAffected)
-				if (rows != 1) throw new DbStateException();
-			ps.close();
-			return keySetId;
-		} catch (SQLException e) {
-			tryToClose(rs, LOG, WARNING);
-			tryToClose(ps, LOG, WARNING);
-			throw new DbException(e);
-		}
-	}
-
-	@Override
-	public void addLocalAuthor(Connection txn, LocalAuthor a)
-			throws DbException {
 		PreparedStatement ps = null;
 		try {
 			String sql = "INSERT INTO localAuthors"
@@ -883,16 +752,17 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " handshakePublicKey, handshakePrivateKey, created)"
 					+ " VALUES (?, ?, ?, ?, ?, ?, ?, ?)";
 			ps = txn.prepareStatement(sql);
-			ps.setBytes(1, a.getId().getBytes());
+			LocalAuthor local = i.getLocalAuthor();
-			ps.setInt(2, a.getFormatVersion());
+			ps.setBytes(1, local.getId().getBytes());
-			ps.setString(3, a.getName());
+			ps.setInt(2, local.getFormatVersion());
-			ps.setBytes(4, a.getPublicKey());
+			ps.setString(3, local.getName());
-			ps.setBytes(5, a.getPrivateKey());
+			ps.setBytes(4, local.getPublicKey().getEncoded());
-			if (a.getHandshakePublicKey() == null) ps.setNull(6, BINARY);
+			ps.setBytes(5, local.getPrivateKey().getEncoded());
-			else ps.setBytes(6, a.getHandshakePublicKey());
+			if (i.getHandshakePublicKey() == null) ps.setNull(6, BINARY);
-			if (a.getHandshakePrivateKey() == null) ps.setNull(7, BINARY);
+			else ps.setBytes(6, i.getHandshakePublicKey().getEncoded());
-			else ps.setBytes(7, a.getHandshakePrivateKey());
+			if (i.getHandshakePrivateKey() == null) ps.setNull(7, BINARY);
-			ps.setLong(8, a.getTimeCreated());
+			else ps.setBytes(7, i.getHandshakePrivateKey().getEncoded());
+			ps.setLong(8, i.getTimeCreated());
 			int affected = ps.executeUpdate();
 			if (affected != 1) throw new DbStateException();
 			ps.close();
@@ -1067,7 +937,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " VALUES (?, ?, ?, ?, ?)";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, p.getId().getBytes());
-			ps.setBytes(2, p.getPublicKey());
+			ps.setBytes(2, p.getPublicKey().getEncoded());
 			ps.setString(3, p.getAlias());
 			ps.setInt(4, p.getState().getValue());
 			ps.setLong(5, p.getTimestamp());
@@ -1100,24 +970,47 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public TransportKeySetId addTransportKeys(Connection txn, ContactId c,
+	public KeySetId addTransportKeys(Connection txn, ContactId c,
+			TransportKeys k) throws DbException {
+		return addTransportKeys(txn, c, null, k);
+	}
+
+	@Override
+	public KeySetId addTransportKeys(Connection txn,
+			PendingContactId p, TransportKeys k) throws DbException {
+		return addTransportKeys(txn, null, p, k);
+	}
+
+	private KeySetId addTransportKeys(Connection txn,
+			@Nullable ContactId c, @Nullable PendingContactId p,
 			TransportKeys k) throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
 			// Store the outgoing keys
-			String sql = "INSERT INTO outgoingKeys (contactId, transportId,"
+			String sql = "INSERT INTO outgoingKeys (transportId, timePeriod,"
-					+ " timePeriod, tagKey, headerKey, stream, active)"
+					+ " contactId, pendingContactId, tagKey, headerKey,"
-					+ " VALUES (?, ?, ?, ?, ?, ?, ?)";
+					+ " stream, active, rootKey, alice)"
+					+ " VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)";
 			ps = txn.prepareStatement(sql);
-			ps.setInt(1, c.getInt());
+			ps.setString(1, k.getTransportId().getString());
-			ps.setString(2, k.getTransportId().getString());
+			ps.setLong(2, k.getTimePeriod());
+			if (c == null) ps.setNull(3, INTEGER);
+			else ps.setInt(3, c.getInt());
+			if (p == null) ps.setNull(4, BINARY);
+			else ps.setBytes(4, p.getBytes());
 			OutgoingKeys outCurr = k.getCurrentOutgoingKeys();
-			ps.setLong(3, outCurr.getTimePeriod());
+			ps.setBytes(5, outCurr.getTagKey().getBytes());
-			ps.setBytes(4, outCurr.getTagKey().getBytes());
+			ps.setBytes(6, outCurr.getHeaderKey().getBytes());
-			ps.setBytes(5, outCurr.getHeaderKey().getBytes());
+			ps.setLong(7, outCurr.getStreamCounter());
-			ps.setLong(6, outCurr.getStreamCounter());
+			ps.setBoolean(8, outCurr.isActive());
-			ps.setBoolean(7, outCurr.isActive());
+			if (k.isHandshakeMode()) {
+				ps.setBytes(9, k.getRootKey().getBytes());
+				ps.setBoolean(10, k.isAlice());
+			} else {
+				ps.setNull(9, BINARY);
+				ps.setNull(10, BOOLEAN);
+			}
 			int affected = ps.executeUpdate();
 			if (affected != 1) throw new DbStateException();
 			ps.close();
@@ -1127,18 +1020,18 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			rs = ps.executeQuery();
 			if (!rs.next()) throw new DbStateException();
-			TransportKeySetId keySetId = new TransportKeySetId(rs.getInt(1));
+			KeySetId keySetId = new KeySetId(rs.getInt(1));
 			if (rs.next()) throw new DbStateException();
 			rs.close();
 			ps.close();
 			// Store the incoming keys
-			sql = "INSERT INTO incomingKeys (keySetId, transportId,"
+			sql = "INSERT INTO incomingKeys (transportId, keySetId,"
 					+ " timePeriod, tagKey, headerKey, base, bitmap,"
 					+ " periodOffset)"
 					+ " VALUES (?, ?, ?, ?, ?, ?, ?, ?)";
 			ps = txn.prepareStatement(sql);
-			ps.setInt(1, keySetId.getInt());
+			ps.setString(1, k.getTransportId().getString());
-			ps.setString(2, k.getTransportId().getString());
+			ps.setInt(2, keySetId.getInt());
 			// Previous time period
 			IncomingKeys inPrev = k.getPreviousIncomingKeys();
 			ps.setLong(3, inPrev.getTimePeriod());
@@ -1248,7 +1141,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public boolean containsLocalAuthor(Connection txn, AuthorId a)
+	public boolean containsIdentity(Connection txn, AuthorId a)
 			throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
@@ -1443,14 +1336,16 @@ abstract class JdbcDatabase implements Database<Connection> {
 			int formatVersion = rs.getInt(2);
 			String name = rs.getString(3);
 			String alias = rs.getString(4);
-			byte[] publicKey = rs.getBytes(5);
+			PublicKey publicKey = new SignaturePublicKey(rs.getBytes(5));
-			byte[] handshakePublicKey = rs.getBytes(6);
+			byte[] handshakePub = rs.getBytes(6);
 			AuthorId localAuthorId = new AuthorId(rs.getBytes(7));
 			boolean verified = rs.getBoolean(8);
 			rs.close();
 			ps.close();
 			Author author =
 					new Author(authorId, formatVersion, name, publicKey);
+			PublicKey handshakePublicKey = handshakePub == null ?
+					null : new AgreementPublicKey(handshakePub);
 			return new Contact(c, author, localAuthorId, alias,
 					handshakePublicKey, verified);
 		} catch (SQLException e) {
@@ -1478,12 +1373,14 @@ abstract class JdbcDatabase implements Database<Connection> {
 				int formatVersion = rs.getInt(3);
 				String name = rs.getString(4);
 				String alias = rs.getString(5);
-				byte[] publicKey = rs.getBytes(6);
+				PublicKey publicKey = new SignaturePublicKey(rs.getBytes(6));
-				byte[] handshakePublicKey = rs.getBytes(7);
+				byte[] handshakePub = rs.getBytes(7);
 				AuthorId localAuthorId = new AuthorId(rs.getBytes(8));
 				boolean verified = rs.getBoolean(9);
 				Author author =
 						new Author(authorId, formatVersion, name, publicKey);
+				PublicKey handshakePublicKey = handshakePub == null ?
+						null : new AgreementPublicKey(handshakePub);
 				contacts.add(new Contact(contactId, author, localAuthorId,
 						alias, handshakePublicKey, verified));
 			}
@@ -1539,12 +1436,14 @@ abstract class JdbcDatabase implements Database<Connection> {
 				int formatVersion = rs.getInt(2);
 				String name = rs.getString(3);
 				String alias = rs.getString(4);
-				byte[] publicKey = rs.getBytes(5);
+				PublicKey publicKey = new SignaturePublicKey(rs.getBytes(5));
-				byte[] handshakePublicKey = rs.getBytes(6);
+				byte[] handshakePub = rs.getBytes(6);
 				AuthorId localAuthorId = new AuthorId(rs.getBytes(7));
 				boolean verified = rs.getBoolean(8);
 				Author author =
 						new Author(remote, formatVersion, name, publicKey);
+				PublicKey handshakePublicKey = handshakePub == null ?
+						null : new AgreementPublicKey(handshakePub);
 				contacts.add(new Contact(contactId, author, localAuthorId,
 						alias, handshakePublicKey, verified));
 			}
@@ -1661,8 +1560,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public LocalAuthor getLocalAuthor(Connection txn, AuthorId a)
+	public Identity getIdentity(Connection txn, AuthorId a) throws DbException {
-			throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
@@ -1676,18 +1574,22 @@ abstract class JdbcDatabase implements Database<Connection> {
 			if (!rs.next()) throw new DbStateException();
 			int formatVersion = rs.getInt(1);
 			String name = rs.getString(2);
-			byte[] publicKey = rs.getBytes(3);
+			PublicKey publicKey = new SignaturePublicKey(rs.getBytes(3));
-			byte[] privateKey = rs.getBytes(4);
+			PrivateKey privateKey = new SignaturePrivateKey(rs.getBytes(4));
-			byte[] handshakePublicKey = rs.getBytes(5);
+			byte[] handshakePub = rs.getBytes(5);
-			byte[] handshakePrivateKey = rs.getBytes(6);
+			byte[] handshakePriv = rs.getBytes(6);
 			long created = rs.getLong(7);
-			LocalAuthor localAuthor = new LocalAuthor(a, formatVersion, name,
-					publicKey, privateKey, handshakePublicKey,
-					handshakePrivateKey, created);
 			if (rs.next()) throw new DbStateException();
 			rs.close();
 			ps.close();
-			return localAuthor;
+			LocalAuthor local = new LocalAuthor(a, formatVersion, name,
+					publicKey, privateKey);
+			PublicKey handshakePublicKey = handshakePub == null ?
+					null : new AgreementPublicKey(handshakePub);
+			PrivateKey handshakePrivateKey = handshakePriv == null ?
+					null : new AgreementPrivateKey(handshakePriv);
+			return new Identity(local, handshakePublicKey, handshakePrivateKey,
+					created);
 		} catch (SQLException e) {
 			tryToClose(rs, LOG, WARNING);
 			tryToClose(ps, LOG, WARNING);
@@ -1696,110 +1598,39 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public Collection<HandshakeKeySet> getHandshakeKeys(Connection txn,
+	public Collection<Identity> getIdentities(Connection txn)
-			TransportId t) throws DbException {
-		PreparedStatement ps = null;
-		ResultSet rs = null;
-		try {
-			// Retrieve the incoming keys
-			String sql = "SELECT timePeriod, tagKey, headerKey, base, bitmap"
-					+ " FROM incomingHandshakeKeys"
-					+ " WHERE transportId = ?"
-					+ " ORDER BY keySetId, periodOffset";
-			ps = txn.prepareStatement(sql);
-			ps.setString(1, t.getString());
-			rs = ps.executeQuery();
-			List<IncomingKeys> inKeys = new ArrayList<>();
-			while (rs.next()) {
-				long timePeriod = rs.getLong(1);
-				SecretKey tagKey = new SecretKey(rs.getBytes(2));
-				SecretKey headerKey = new SecretKey(rs.getBytes(3));
-				long windowBase = rs.getLong(4);
-				byte[] windowBitmap = rs.getBytes(5);
-				inKeys.add(new IncomingKeys(tagKey, headerKey, timePeriod,
-						windowBase, windowBitmap));
-			}
-			rs.close();
-			ps.close();
-			// Retrieve the outgoing keys in the same order
-			sql = "SELECT keySetId, contactId, pendingContactId, timePeriod,"
-					+ " tagKey, headerKey, rootKey, alice, stream"
-					+ " FROM outgoingHandshakeKeys"
-					+ " WHERE transportId = ?"
-					+ " ORDER BY keySetId";
-			ps = txn.prepareStatement(sql);
-			ps.setString(1, t.getString());
-			rs = ps.executeQuery();
-			Collection<HandshakeKeySet> keys = new ArrayList<>();
-			for (int i = 0; rs.next(); i++) {
-				// There should be three times as many incoming keys
-				if (inKeys.size() < (i + 1) * 3) throw new DbStateException();
-				HandshakeKeySetId keySetId =
-						new HandshakeKeySetId(rs.getInt(1));
-				ContactId contactId = null;
-				int cId = rs.getInt(2);
-				if (!rs.wasNull()) contactId = new ContactId(cId);
-				PendingContactId pendingContactId = null;
-				byte[] pId = rs.getBytes(3);
-				if (!rs.wasNull()) pendingContactId = new PendingContactId(pId);
-				long timePeriod = rs.getLong(4);
-				SecretKey tagKey = new SecretKey(rs.getBytes(5));
-				SecretKey headerKey = new SecretKey(rs.getBytes(6));
-				SecretKey rootKey = new SecretKey(rs.getBytes(7));
-				boolean alice = rs.getBoolean(8);
-				long streamCounter = rs.getLong(9);
-				OutgoingKeys outCurr = new OutgoingKeys(tagKey, headerKey,
-						timePeriod, streamCounter, true);
-				IncomingKeys inPrev = inKeys.get(i * 3);
-				IncomingKeys inCurr = inKeys.get(i * 3 + 1);
-				IncomingKeys inNext = inKeys.get(i * 3 + 2);
-				HandshakeKeys handshakeKeys = new HandshakeKeys(t, inPrev,
-						inCurr, inNext, outCurr, rootKey, alice);
-				if (contactId == null) {
-					if (pendingContactId == null) throw new DbStateException();
-					keys.add(new HandshakeKeySet(keySetId, pendingContactId,
-							handshakeKeys));
-				} else {
-					if (pendingContactId != null) throw new DbStateException();
-					keys.add(new HandshakeKeySet(keySetId, contactId,
-							handshakeKeys));
-				}
-			}
-			rs.close();
-			ps.close();
-			return keys;
-		} catch (SQLException e) {
-			tryToClose(rs, LOG, WARNING);
-			tryToClose(ps, LOG, WARNING);
-			throw new DbException(e);
-		}
-	}
-
-	@Override
-	public Collection<LocalAuthor> getLocalAuthors(Connection txn)
 			throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
 			String sql = "SELECT authorId, formatVersion, name, publicKey,"
-					+ " privateKey, created"
+					+ " privateKey, handshakePublicKey, handshakePrivateKey,"
+					+ " created"
 					+ " FROM localAuthors";
 			ps = txn.prepareStatement(sql);
 			rs = ps.executeQuery();
-			List<LocalAuthor> authors = new ArrayList<>();
+			List<Identity> identities = new ArrayList<>();
 			while (rs.next()) {
 				AuthorId authorId = new AuthorId(rs.getBytes(1));
 				int formatVersion = rs.getInt(2);
 				String name = rs.getString(3);
-				byte[] publicKey = rs.getBytes(4);
+				PublicKey publicKey = new SignaturePublicKey(rs.getBytes(4));
-				byte[] privateKey = rs.getBytes(5);
+				PrivateKey privateKey = new SignaturePrivateKey(rs.getBytes(5));
-				long created = rs.getLong(6);
+				byte[] handshakePub = rs.getBytes(6);
-				authors.add(new LocalAuthor(authorId, formatVersion, name,
+				byte[] handshakePriv = rs.getBytes(7);
-						publicKey, privateKey, created));
+				long created = rs.getLong(8);
+				LocalAuthor local = new LocalAuthor(authorId, formatVersion,
+						name, publicKey, privateKey);
+				PublicKey handshakePublicKey = handshakePub == null ?
+						null : new AgreementPublicKey(handshakePub);
+				PrivateKey handshakePrivateKey = handshakePriv == null ?
+						null : new AgreementPrivateKey(handshakePriv);
+				identities.add(new Identity(local, handshakePublicKey,
+						handshakePrivateKey, created));
 			}
 			rs.close();
 			ps.close();
-			return authors;
+			return identities;
 		} catch (SQLException e) {
 			tryToClose(rs, LOG, WARNING);
 			tryToClose(ps, LOG, WARNING);
@@ -2390,7 +2221,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			List<PendingContact> pendingContacts = new ArrayList<>();
 			while (rs.next()) {
 				PendingContactId id = new PendingContactId(rs.getBytes(1));
-				byte[] publicKey = rs.getBytes(2);
+				PublicKey publicKey = new AgreementPublicKey(rs.getBytes(2));
 				String alias = rs.getString(3);
 				PendingContactState state =
 						PendingContactState.fromValue(rs.getInt(4));
@@ -2497,8 +2328,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 			rs.close();
 			ps.close();
 			// Retrieve the outgoing keys in the same order
-			sql = "SELECT keySetId, contactId, timePeriod,"
+			sql = "SELECT keySetId, timePeriod, contactId, pendingContactId,"
-					+ " tagKey, headerKey, stream, active"
+					+ " tagKey, headerKey, stream, active, rootKey, alice"
 					+ " FROM outgoingKeys"
 					+ " WHERE transportId = ?"
 					+ " ORDER BY keySetId";
@@ -2509,23 +2340,34 @@ abstract class JdbcDatabase implements Database<Connection> {
 			for (int i = 0; rs.next(); i++) {
 				// There should be three times as many incoming keys
 				if (inKeys.size() < (i + 1) * 3) throw new DbStateException();
-				TransportKeySetId keySetId =
+				KeySetId keySetId = new KeySetId(rs.getInt(1));
-						new TransportKeySetId(rs.getInt(1));
+				long timePeriod = rs.getLong(2);
-				ContactId contactId = new ContactId(rs.getInt(2));
+				int cId = rs.getInt(3);
-				long timePeriod = rs.getLong(3);
+				ContactId contactId = rs.wasNull() ? null : new ContactId(cId);
-				SecretKey tagKey = new SecretKey(rs.getBytes(4));
+				byte[] pId = rs.getBytes(4);
-				SecretKey headerKey = new SecretKey(rs.getBytes(5));
+				PendingContactId pendingContactId = pId == null ?
-				long streamCounter = rs.getLong(6);
+						null : new PendingContactId(pId);
-				boolean active = rs.getBoolean(7);
+				SecretKey tagKey = new SecretKey(rs.getBytes(5));
+				SecretKey headerKey = new SecretKey(rs.getBytes(6));
+				long streamCounter = rs.getLong(7);
+				boolean active = rs.getBoolean(8);
+				byte[] rootKey = rs.getBytes(9);
+				boolean alice = rs.getBoolean(10);
 				OutgoingKeys outCurr = new OutgoingKeys(tagKey, headerKey,
 						timePeriod, streamCounter, active);
 				IncomingKeys inPrev = inKeys.get(i * 3);
 				IncomingKeys inCurr = inKeys.get(i * 3 + 1);
 				IncomingKeys inNext = inKeys.get(i * 3 + 2);
-				TransportKeys transportKeys = new TransportKeys(t, inPrev,
+				TransportKeys transportKeys;
-						inCurr, inNext, outCurr);
+				if (rootKey == null) {
+					transportKeys = new TransportKeys(t, inPrev, inCurr,
+							inNext, outCurr);
+				} else {
+					transportKeys = new TransportKeys(t, inPrev, inCurr,
+							inNext, outCurr, new SecretKey(rootKey), alice);
+				}
 				keys.add(new TransportKeySet(keySetId, contactId,
-						transportKeys));
+						pendingContactId, transportKeys));
 			}
 			rs.close();
 			ps.close();
@@ -2539,26 +2381,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 
 	@Override
 	public void incrementStreamCounter(Connection txn, TransportId t,
-			HandshakeKeySetId k) throws DbException {
+			KeySetId k) throws DbException {
-		PreparedStatement ps = null;
-		try {
-			String sql = "UPDATE outgoingHandshakeKeys SET stream = stream + 1"
-					+ " WHERE transportId = ? AND keySetId = ?";
-			ps = txn.prepareStatement(sql);
-			ps.setString(1, t.getString());
-			ps.setInt(2, k.getInt());
-			int affected = ps.executeUpdate();
-			if (affected != 1) throw new DbStateException();
-			ps.close();
-		} catch (SQLException e) {
-			tryToClose(ps, LOG, WARNING);
-			throw new DbException(e);
-		}
-	}
-
-	@Override
-	public void incrementStreamCounter(Connection txn, TransportId t,
-			TransportKeySetId k) throws DbException {
 		PreparedStatement ps = null;
 		try {
 			String sql = "UPDATE outgoingKeys SET stream = stream + 1"
@@ -2937,29 +2760,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public void removeHandshakeKeys(Connection txn, TransportId t,
+	public void removeIdentity(Connection txn, AuthorId a) throws DbException {
-			HandshakeKeySetId k) throws DbException {
-		PreparedStatement ps = null;
-		try {
-			// Delete any existing outgoing keys - this will also remove any
-			// incoming keys with the same key set ID
-			String sql = "DELETE FROM outgoingHandshakeKeys"
-					+ " WHERE transportId = ? AND keySetId = ?";
-			ps = txn.prepareStatement(sql);
-			ps.setString(1, t.getString());
-			ps.setInt(2, k.getInt());
-			int affected = ps.executeUpdate();
-			if (affected < 0) throw new DbStateException();
-			ps.close();
-		} catch (SQLException e) {
-			tryToClose(ps, LOG, WARNING);
-			throw new DbException(e);
-		}
-	}
-
-	@Override
-	public void removeLocalAuthor(Connection txn, AuthorId a)
-			throws DbException {
 		PreparedStatement ps = null;
 		try {
 			String sql = "DELETE FROM localAuthors WHERE authorId = ?";
@@ -3070,8 +2871,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public void removeTransportKeys(Connection txn, TransportId t,
+	public void removeTransportKeys(Connection txn, TransportId t, KeySetId k)
-			TransportKeySetId k) throws DbException {
+			throws DbException {
 		PreparedStatement ps = null;
 		try {
 			// Delete any existing outgoing keys - this will also remove any
@@ -3176,6 +2977,27 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	@Override
+	public void setHandshakeKeyPair(Connection txn, AuthorId local,
+			PublicKey publicKey, PrivateKey privateKey) throws DbException {
+		PreparedStatement ps = null;
+		try {
+			String sql = "UPDATE localAuthors"
+					+ " SET handshakePublicKey = ?, handshakePrivateKey = ?"
+					+ " WHERE authorId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, publicKey.getEncoded());
+			ps.setBytes(2, privateKey.getEncoded());
+			ps.setBytes(3, local.getBytes());
+			int affected = ps.executeUpdate();
+			if (affected < 0 || affected > 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			tryToClose(ps, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	public void setMessageShared(Connection txn, MessageId m)
 			throws DbException {
@@ -3266,7 +3088,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(1, state.getValue());
 			ps.setBytes(2, p.getBytes());
 			int affected = ps.executeUpdate();
-			if (affected != 1) throw new DbStateException();
+			if (affected < 0 || affected > 1) throw new DbStateException();
 			ps.close();
 		} catch (SQLException e) {
 			tryToClose(ps, LOG, WARNING);
@@ -3275,7 +3097,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public void setReorderingWindow(Connection txn, TransportKeySetId k,
+	public void setReorderingWindow(Connection txn, KeySetId k,
 			TransportId t, long timePeriod, long base, byte[] bitmap)
 			throws DbException {
 		PreparedStatement ps = null;
@@ -3298,33 +3120,9 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
-	@Override
-	public void setReorderingWindow(Connection txn, HandshakeKeySetId k,
-			TransportId t, long timePeriod, long base, byte[] bitmap)
-			throws DbException {
-		PreparedStatement ps = null;
-		try {
-			String sql = "UPDATE incomingHandshakeKeys SET base = ?, bitmap = ?"
-					+ " WHERE transportId = ? AND keySetId = ?"
-					+ " AND timePeriod = ?";
-			ps = txn.prepareStatement(sql);
-			ps.setLong(1, base);
-			ps.setBytes(2, bitmap);
-			ps.setString(3, t.getString());
-			ps.setInt(4, k.getInt());
-			ps.setLong(5, timePeriod);
-			int affected = ps.executeUpdate();
-			if (affected < 0 || affected > 1) throw new DbStateException();
-			ps.close();
-		} catch (SQLException e) {
-			tryToClose(ps, LOG, WARNING);
-			throw new DbException(e);
-		}
-	}
-
 	@Override
 	public void setTransportKeysActive(Connection txn, TransportId t,
-			TransportKeySetId k) throws DbException {
+			KeySetId k) throws DbException {
 		PreparedStatement ps = null;
 		try {
 			String sql = "UPDATE outgoingKeys SET active = true"
@@ -3444,71 +3242,4 @@ abstract class JdbcDatabase implements Database<Connection> {
 			throw new DbException(e);
 		}
 	}
-
-	@Override
-	public void updateHandshakeKeys(Connection txn, HandshakeKeySet ks)
-			throws DbException {
-		PreparedStatement ps = null;
-		try {
-			// Update the outgoing keys
-			String sql = "UPDATE outgoingHandshakeKeys SET timePeriod = ?,"
-					+ " tagKey = ?, headerKey = ?, stream = ?"
-					+ " WHERE transportId = ? AND keySetId = ?";
-			ps = txn.prepareStatement(sql);
-			HandshakeKeys k = ks.getKeys();
-			OutgoingKeys outCurr = k.getCurrentOutgoingKeys();
-			ps.setLong(1, outCurr.getTimePeriod());
-			ps.setBytes(2, outCurr.getTagKey().getBytes());
-			ps.setBytes(3, outCurr.getHeaderKey().getBytes());
-			ps.setLong(4, outCurr.getStreamCounter());
-			ps.setString(5, k.getTransportId().getString());
-			ps.setInt(6, ks.getKeySetId().getInt());
-			int affected = ps.executeUpdate();
-			if (affected < 0 || affected > 1) throw new DbStateException();
-			ps.close();
-			// Update the incoming keys
-			sql = "UPDATE incomingHandshakeKeys SET timePeriod = ?,"
-					+ " tagKey = ?, headerKey = ?, base = ?, bitmap = ?"
-					+ " WHERE transportId = ? AND keySetId = ?"
-					+ " AND periodOffset = ?";
-			ps = txn.prepareStatement(sql);
-			ps.setString(6, k.getTransportId().getString());
-			ps.setInt(7, ks.getKeySetId().getInt());
-			// Previous time period
-			IncomingKeys inPrev = k.getPreviousIncomingKeys();
-			ps.setLong(1, inPrev.getTimePeriod());
-			ps.setBytes(2, inPrev.getTagKey().getBytes());
-			ps.setBytes(3, inPrev.getHeaderKey().getBytes());
-			ps.setLong(4, inPrev.getWindowBase());
-			ps.setBytes(5, inPrev.getWindowBitmap());
-			ps.setInt(8, OFFSET_PREV);
-			ps.addBatch();
-			// Current time period
-			IncomingKeys inCurr = k.getCurrentIncomingKeys();
-			ps.setLong(1, inCurr.getTimePeriod());
-			ps.setBytes(2, inCurr.getTagKey().getBytes());
-			ps.setBytes(3, inCurr.getHeaderKey().getBytes());
-			ps.setLong(4, inCurr.getWindowBase());
-			ps.setBytes(5, inCurr.getWindowBitmap());
-			ps.setInt(8, OFFSET_CURR);
-			ps.addBatch();
-			// Next time period
-			IncomingKeys inNext = k.getNextIncomingKeys();
-			ps.setLong(1, inNext.getTimePeriod());
-			ps.setBytes(2, inNext.getTagKey().getBytes());
-			ps.setBytes(3, inNext.getHeaderKey().getBytes());
-			ps.setLong(4, inNext.getWindowBase());
-			ps.setBytes(5, inNext.getWindowBitmap());
-			ps.setInt(8, OFFSET_NEXT);
-			ps.addBatch();
-			int[] batchAffected = ps.executeBatch();
-			if (batchAffected.length != 3) throw new DbStateException();
-			for (int rows : batchAffected)
-				if (rows < 0 || rows > 1) throw new DbStateException();
-			ps.close();
-		} catch (SQLException e) {
-			tryToClose(ps, LOG, WARNING);
-			throw new DbException(e);
-		}
-	}
 }

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

@@ -0,0 +1,58 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.db.DbException;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.logging.Logger;
+
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.db.JdbcUtils.tryToClose;
+
+class Migration43_44 implements Migration<Connection> {
+
+	private static final Logger LOG = getLogger(Migration43_44.class.getName());
+
+	private final DatabaseTypes dbTypes;
+
+	Migration43_44(DatabaseTypes dbTypes) {
+		this.dbTypes = dbTypes;
+	}
+
+	@Override
+	public int getStartVersion() {
+		return 43;
+	}
+
+	@Override
+	public int getEndVersion() {
+		return 44;
+	}
+
+	@Override
+	public void migrate(Connection txn) throws DbException {
+		Statement s = null;
+		try {
+			s = txn.createStatement();
+			s.execute("DROP TABLE outgoingHandshakeKeys");
+			s.execute("DROP TABLE incomingHandshakeKeys");
+			s.execute("ALTER TABLE outgoingKeys"
+					+ " ALTER COLUMN contactId DROP NOT NULL");
+			s.execute(dbTypes.replaceTypes("ALTER TABLE outgoingKeys"
+					+ " ADD COLUMN pendingContactId _HASH"));
+			s.execute("ALTER TABLE outgoingKeys"
+					+ " ADD FOREIGN KEY (pendingContactId)"
+					+ " REFERENCES pendingContacts (pendingContactId)"
+					+ " ON DELETE CASCADE");
+			s.execute(dbTypes.replaceTypes("ALTER TABLE outgoingKeys"
+					+ " ADD COLUMN rootKey _SECRET"));
+			s.execute("ALTER TABLE outgoingKeys"
+					+ " ADD COLUMN alice BOOLEAN");
+		} catch (SQLException e) {
+			tryToClose(s, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+}

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

@@ -1,14 +1,14 @@
 package org.briarproject.bramble.identity;
 
 import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.KeyPair;
+import org.briarproject.bramble.api.crypto.PrivateKey;
+import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorFactory;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.bramble.util.ByteUtils;
-import org.briarproject.bramble.util.StringUtils;
 
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
@@ -16,50 +16,46 @@ import javax.inject.Inject;
 import static org.briarproject.bramble.api.identity.Author.FORMAT_VERSION;
 import static org.briarproject.bramble.api.identity.AuthorId.LABEL;
 import static org.briarproject.bramble.util.ByteUtils.INT_32_BYTES;
+import static org.briarproject.bramble.util.ByteUtils.writeUint32;
+import static org.briarproject.bramble.util.StringUtils.toUtf8;
 
 @Immutable
 @NotNullByDefault
 class AuthorFactoryImpl implements AuthorFactory {
 
 	private final CryptoComponent crypto;
-	private final Clock clock;
 
 	@Inject
-	AuthorFactoryImpl(CryptoComponent crypto, Clock clock) {
+	AuthorFactoryImpl(CryptoComponent crypto) {
 		this.crypto = crypto;
-		this.clock = clock;
 	}
 
 	@Override
-	public Author createAuthor(String name, byte[] publicKey) {
+	public Author createAuthor(String name, PublicKey publicKey) {
 		return createAuthor(FORMAT_VERSION, name, publicKey);
 	}
 
 	@Override
 	public Author createAuthor(int formatVersion, String name,
-			byte[] publicKey) {
+			PublicKey publicKey) {
 		AuthorId id = getId(formatVersion, name, publicKey);
 		return new Author(id, formatVersion, name, publicKey);
 	}
 
 	@Override
-	public LocalAuthor createLocalAuthor(String name, byte[] publicKey,
+	public LocalAuthor createLocalAuthor(String name) {
-			byte[] privateKey) {
+		KeyPair signatureKeyPair = crypto.generateSignatureKeyPair();
-		return createLocalAuthor(FORMAT_VERSION, name, publicKey, privateKey);
+		PublicKey publicKey = signatureKeyPair.getPublic();
+		PrivateKey privateKey = signatureKeyPair.getPrivate();
+		AuthorId id = getId(FORMAT_VERSION, name, publicKey);
+		return new LocalAuthor(id, FORMAT_VERSION, name, publicKey, privateKey);
 	}
 
-	@Override
+	private AuthorId getId(int formatVersion, String name,
-	public LocalAuthor createLocalAuthor(int formatVersion, String name,
+			PublicKey publicKey) {
-			byte[] publicKey, byte[] privateKey) {
-		AuthorId id = getId(formatVersion, name, publicKey);
-		return new LocalAuthor(id, formatVersion, name, publicKey, privateKey,
-				clock.currentTimeMillis());
-	}
-
-	private AuthorId getId(int formatVersion, String name, byte[] publicKey) {
 		byte[] formatVersionBytes = new byte[INT_32_BYTES];
-		ByteUtils.writeUint32(formatVersion, formatVersionBytes, 0);
+		writeUint32(formatVersion, formatVersionBytes, 0);
 		return new AuthorId(crypto.hash(LABEL, formatVersionBytes,
-				StringUtils.toUtf8(name), publicKey));
+				toUtf8(name), publicKey.getEncoded()));
 	}
 }

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

@@ -2,101 +2,170 @@ package org.briarproject.bramble.identity;
 
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.KeyPair;
+import org.briarproject.bramble.api.crypto.PrivateKey;
+import org.briarproject.bramble.api.crypto.PublicKey;
 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.identity.AuthorFactory;
+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.lifecycle.LifecycleManager.OpenDatabaseHook;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.Clock;
 
+import java.util.Collection;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 import javax.inject.Inject;
 
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.now;
 
 @ThreadSafe
 @NotNullByDefault
-class IdentityManagerImpl implements IdentityManager {
+class IdentityManagerImpl implements IdentityManager, OpenDatabaseHook {
 
 	private static final Logger LOG =
-			Logger.getLogger(IdentityManagerImpl.class.getName());
+			getLogger(IdentityManagerImpl.class.getName());
 
 	private final DatabaseComponent db;
 	private final CryptoComponent crypto;
 	private final AuthorFactory authorFactory;
+	private final Clock clock;
 
-	// The local author is immutable so we can cache it
+	/**
+	 * The user's identity, or null if no identity has been registered or
+	 * loaded. If non-null, this identity always has handshake keys.
+	 */
 	@Nullable
-	private volatile LocalAuthor cachedAuthor;
+	private volatile Identity cachedIdentity = null;
+
+	/**
+	 * True if {@code cachedIdentity} was registered via
+	 * {@link #registerIdentity(Identity)} and should be stored when
+	 * {@link #onDatabaseOpened(Transaction)} is called.
+	 */
+
+	private volatile boolean shouldStoreIdentity = false;
+
+	/**
+	 * True if the handshake keys in {@code cachedIdentity} were generated
+	 * when the identity was loaded and should be stored when
+	 * {@link #onDatabaseOpened(Transaction)} is called.
+	 */
+	private volatile boolean shouldStoreKeys = false;
 
 	@Inject
 	IdentityManagerImpl(DatabaseComponent db, CryptoComponent crypto,
-			AuthorFactory authorFactory) {
+			AuthorFactory authorFactory, Clock clock) {
 		this.db = db;
 		this.crypto = crypto;
 		this.authorFactory = authorFactory;
+		this.clock = clock;
 	}
 
 	@Override
-	public LocalAuthor createLocalAuthor(String name) {
+	public Identity createIdentity(String name) {
 		long start = now();
-		KeyPair keyPair = crypto.generateSignatureKeyPair();
+		LocalAuthor localAuthor = authorFactory.createLocalAuthor(name);
-		byte[] publicKey = keyPair.getPublic().getEncoded();
+		KeyPair handshakeKeyPair = crypto.generateAgreementKeyPair();
-		byte[] privateKey = keyPair.getPrivate().getEncoded();
+		PublicKey handshakePub = handshakeKeyPair.getPublic();
-		LocalAuthor localAuthor = authorFactory.createLocalAuthor(name,
+		PrivateKey handshakePriv = handshakeKeyPair.getPrivate();
-				publicKey, privateKey);
+		logDuration(LOG, "Creating identity", start);
-		logDuration(LOG, "Creating local author", start);
+		return new Identity(localAuthor, handshakePub, handshakePriv,
-		return localAuthor;
+				clock.currentTimeMillis());
 	}
 
 	@Override
-	public void registerLocalAuthor(LocalAuthor a) {
+	public void registerIdentity(Identity i) {
-		cachedAuthor = a;
+		if (!i.hasHandshakeKeyPair()) throw new IllegalArgumentException();
-		LOG.info("Local author registered");
+		cachedIdentity = i;
+		shouldStoreIdentity = true;
+		LOG.info("Identity registered");
 	}
 
 	@Override
-	public void storeLocalAuthor() throws DbException {
+	public void onDatabaseOpened(Transaction txn) throws DbException {
-		LocalAuthor cached = cachedAuthor;
+		Identity cached = getCachedIdentity(txn);
-		if (cached == null) {
+		if (shouldStoreIdentity) {
-			LOG.info("No local author to store");
+			// The identity was registered at startup - store it
-			return;
+			db.addIdentity(txn, cached);
+			LOG.info("Identity stored");
+		} else if (shouldStoreKeys) {
+			// Handshake keys were generated when loading the identity -
+			// store them
+			PublicKey handshakePub =
+					requireNonNull(cached.getHandshakePublicKey());
+			PrivateKey handshakePriv =
+					requireNonNull(cached.getHandshakePrivateKey());
+			db.setHandshakeKeyPair(txn, cached.getId(), handshakePub,
+					handshakePriv);
+			LOG.info("Handshake key pair stored");
 		}
-		db.transaction(false, txn -> db.addLocalAuthor(txn, cached));
-		LOG.info("Local author stored");
 	}
 
 	@Override
 	public LocalAuthor getLocalAuthor() throws DbException {
-		if (cachedAuthor == null) {
+		Identity cached = cachedIdentity;
-			cachedAuthor =
+		if (cached == null)
-					db.transactionWithResult(true, this::loadLocalAuthor);
+			cached = db.transactionWithResult(true, this::getCachedIdentity);
-			LOG.info("Local author loaded");
+		return cached.getLocalAuthor();
-		}
-		LocalAuthor cached = cachedAuthor;
-		if (cached == null) throw new AssertionError();
-		return cached;
 	}
 
-
 	@Override
 	public LocalAuthor getLocalAuthor(Transaction txn) throws DbException {
-		if (cachedAuthor == null) {
+		return getCachedIdentity(txn).getLocalAuthor();
-			cachedAuthor = loadLocalAuthor(txn);
+	}
-			LOG.info("Local author loaded");
+
-		}
+	@Override
-		LocalAuthor cached = cachedAuthor;
+	public KeyPair getHandshakeKeys(Transaction txn) throws DbException {
-		if (cached == null) throw new AssertionError();
+		Identity cached = getCachedIdentity(txn);
+		PublicKey handshakePub = requireNonNull(cached.getHandshakePublicKey());
+		PrivateKey handshakePriv =
+				requireNonNull(cached.getHandshakePrivateKey());
+		return new KeyPair(handshakePub, handshakePriv);
+	}
+
+	/**
+	 * Loads the identity if necessary and returns it. If
+	 * {@code cachedIdentity} was not already set by calling
+	 * {@link #registerIdentity(Identity)}, this method sets it. If
+	 * {@code cachedIdentity} was already set, either by calling
+	 * {@link #registerIdentity(Identity)} or by a previous call to this
+	 * method, then this method returns the cached identity without hitting
+	 * the database.
+	 */
+	private Identity getCachedIdentity(Transaction txn) throws DbException {
+		Identity cached = cachedIdentity;
+		if (cached == null)
+			cachedIdentity = cached = loadIdentityWithKeyPair(txn);
 		return cached;
 	}
 
-	private LocalAuthor loadLocalAuthor(Transaction txn) throws DbException {
+	/**
-		return db.getLocalAuthors(txn).iterator().next();
+	 * Loads and returns the identity, generating a handshake key pair if
+	 * necessary and setting {@code shouldStoreKeys} if a handshake key pair
+	 * was generated.
+	 */
+	private Identity loadIdentityWithKeyPair(Transaction txn)
+			throws DbException {
+		Collection<Identity> identities = db.getIdentities(txn);
+		if (identities.size() != 1) throw new DbException();
+		Identity i = identities.iterator().next();
+		LOG.info("Identity loaded");
+		if (i.hasHandshakeKeyPair()) return i;
+		KeyPair handshakeKeyPair = crypto.generateAgreementKeyPair();
+		PublicKey handshakePub = handshakeKeyPair.getPublic();
+		PrivateKey handshakePriv = handshakeKeyPair.getPrivate();
+		LOG.info("Handshake key pair generated");
+		shouldStoreKeys = true;
+		return new Identity(i.getLocalAuthor(), handshakePub, handshakePriv,
+				i.getTimeCreated());
 	}
-
 }

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

@@ -2,6 +2,7 @@ package org.briarproject.bramble.identity;
 
 import org.briarproject.bramble.api.identity.AuthorFactory;
 import org.briarproject.bramble.api.identity.IdentityManager;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 
 import javax.inject.Inject;
 import javax.inject.Singleton;
@@ -24,8 +25,9 @@ public class IdentityModule {
 
 	@Provides
 	@Singleton
-	IdentityManager provideIdentityManager(
+	IdentityManager provideIdentityManager(LifecycleManager lifecycleManager,
 			IdentityManagerImpl identityManager) {
+		lifecycleManager.registerOpenDatabaseHook(identityManager);
 		return identityManager;
 	}
 }

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

@@ -1,13 +1,13 @@
 package org.briarproject.bramble.keyagreement;
 
 import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.UnsupportedVersionException;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.data.BdfReader;
 import org.briarproject.bramble.api.data.BdfReaderFactory;
 import org.briarproject.bramble.api.keyagreement.Payload;
 import org.briarproject.bramble.api.keyagreement.PayloadParser;
 import org.briarproject.bramble.api.keyagreement.TransportDescriptor;
-import org.briarproject.bramble.api.keyagreement.UnsupportedVersionException;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.BluetoothConstants;
 import org.briarproject.bramble.api.plugin.LanTcpConstants;

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

@@ -7,13 +7,11 @@ import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.MigrationListener;
 import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.lifecycle.Service;
 import org.briarproject.bramble.api.lifecycle.ServiceException;
 import org.briarproject.bramble.api.lifecycle.event.LifecycleEvent;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.sync.Client;
 
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
@@ -28,6 +26,7 @@ import javax.inject.Inject;
 import static java.util.logging.Level.FINE;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.COMPACTING_DATABASE;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.MIGRATING_DATABASE;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.RUNNING;
@@ -49,14 +48,13 @@ import static org.briarproject.bramble.util.LogUtils.now;
 class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
 
 	private static final Logger LOG =
-			Logger.getLogger(LifecycleManagerImpl.class.getName());
+			getLogger(LifecycleManagerImpl.class.getName());
 
 	private final DatabaseComponent db;
 	private final EventBus eventBus;
 	private final List<Service> services;
-	private final List<Client> clients;
+	private final List<OpenDatabaseHook> openDatabaseHooks;
 	private final List<ExecutorService> executors;
-	private final IdentityManager identityManager;
 	private final Semaphore startStopSemaphore = new Semaphore(1);
 	private final CountDownLatch dbLatch = new CountDownLatch(1);
 	private final CountDownLatch startupLatch = new CountDownLatch(1);
@@ -65,13 +63,11 @@ class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
 	private volatile LifecycleState state = STARTING;
 
 	@Inject
-	LifecycleManagerImpl(DatabaseComponent db, EventBus eventBus,
+	LifecycleManagerImpl(DatabaseComponent db, EventBus eventBus) {
-			IdentityManager identityManager) {
 		this.db = db;
 		this.eventBus = eventBus;
-		this.identityManager = identityManager;
 		services = new CopyOnWriteArrayList<>();
-		clients = new CopyOnWriteArrayList<>();
+		openDatabaseHooks = new CopyOnWriteArrayList<>();
 		executors = new CopyOnWriteArrayList<>();
 	}
 
@@ -83,10 +79,12 @@ class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
 	}
 
 	@Override
-	public void registerClient(Client c) {
+	public void registerOpenDatabaseHook(OpenDatabaseHook hook) {
-		if (LOG.isLoggable(INFO))
+		if (LOG.isLoggable(INFO)) {
-			LOG.info("Registering client " + c.getClass().getSimpleName());
+			LOG.info("Registering open database hook "
-		clients.add(c);
+					+ hook.getClass().getSimpleName());
+		}
+		openDatabaseHooks.add(hook);
 	}
 
 	@Override
@@ -102,28 +100,28 @@ class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
 			return ALREADY_RUNNING;
 		}
 		try {
-			LOG.info("Starting services");
+			LOG.info("Opening database");
 			long start = now();
-
 			boolean reopened = db.open(dbKey, this);
 			if (reopened) logDuration(LOG, "Reopening database", start);
 			else logDuration(LOG, "Creating database", start);
-			identityManager.storeLocalAuthor();
 
+			db.transaction(false, txn -> {
+				for (OpenDatabaseHook hook : openDatabaseHooks) {
+					long start1 = now();
+					hook.onDatabaseOpened(txn);
+					if (LOG.isLoggable(FINE)) {
+						logDuration(LOG, "Calling open database hook "
+								+ hook.getClass().getSimpleName(), start1);
+					}
+				}
+			});
+
+			LOG.info("Starting services");
 			state = STARTING_SERVICES;
 			dbLatch.countDown();
 			eventBus.broadcast(new LifecycleEvent(STARTING_SERVICES));
 
-			db.transaction(false, txn -> {
-				for (Client c : clients) {
-					long start1 = now();
-					c.createLocalState(txn);
-					if (LOG.isLoggable(FINE)) {
-						logDuration(LOG, "Starting client "
-								+ c.getClass().getSimpleName(), start1);
-					}
-				}
-			});
 			for (Service s : services) {
 				start = now();
 				s.startService();

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

@@ -96,6 +96,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			TransportConnectionReader r) throws IOException {
 		InputStream streamReader = streamReaderFactory.createStreamReader(
 				r.getInputStream(), ctx);
+		// TODO: Pending contacts, handshake mode
 		return syncSessionFactory.createIncomingSession(ctx.getContactId(),
 				streamReader);
 	}
@@ -104,6 +105,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			TransportConnectionWriter w) throws IOException {
 		StreamWriter streamWriter = streamWriterFactory.createStreamWriter(
 				w.getOutputStream(), ctx);
+		// TODO: Pending contacts, handshake mode
 		return syncSessionFactory.createSimplexOutgoingSession(
 				ctx.getContactId(), w.getMaxLatency(), streamWriter);
 	}
@@ -112,6 +114,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			TransportConnectionWriter w) throws IOException {
 		StreamWriter streamWriter = streamWriterFactory.createStreamWriter(
 				w.getOutputStream(), ctx);
+		// TODO: Pending contacts, handshake mode
 		return syncSessionFactory.createDuplexOutgoingSession(
 				ctx.getContactId(), w.getMaxLatency(), w.getMaxIdleTime(),
 				streamWriter);
@@ -145,6 +148,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 				disposeReader(false, false);
 				return;
 			}
+			// TODO: Pending contacts
 			ContactId contactId = ctx.getContactId();
 			connectionRegistry.registerConnection(contactId, transportId, true);
 			try {
@@ -388,7 +392,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 				return;
 			}
 			// Check that the stream comes from the expected contact
-			if (!ctx.getContactId().equals(contactId)) {
+			if (!contactId.equals(ctx.getContactId())) {
 				LOG.warning("Wrong contact ID for returning stream");
 				disposeReader(true, true);
 				return;

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

@@ -48,7 +48,7 @@ public class PropertiesModule {
 			ValidationManager validationManager, ContactManager contactManager,
 			ClientVersioningManager clientVersioningManager,
 			TransportPropertyManagerImpl transportPropertyManager) {
-		lifecycleManager.registerClient(transportPropertyManager);
+		lifecycleManager.registerOpenDatabaseHook(transportPropertyManager);
 		validationManager.registerIncomingMessageHook(CLIENT_ID, MAJOR_VERSION,
 				transportPropertyManager);
 		contactManager.registerContactHook(transportPropertyManager);

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

@@ -13,11 +13,11 @@ import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager.OpenDatabaseHook;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.properties.TransportPropertyManager;
-import org.briarproject.bramble.api.sync.Client;
 import org.briarproject.bramble.api.sync.Group;
 import org.briarproject.bramble.api.sync.Group.Visibility;
 import org.briarproject.bramble.api.sync.GroupId;
@@ -40,7 +40,8 @@ import javax.inject.Inject;
 @Immutable
 @NotNullByDefault
 class TransportPropertyManagerImpl implements TransportPropertyManager,
-		Client, ContactHook, ClientVersioningHook, IncomingMessageHook {
+		OpenDatabaseHook, ContactHook, ClientVersioningHook,
+		IncomingMessageHook {
 
 	private final DatabaseComponent db;
 	private final ClientHelper clientHelper;
@@ -67,7 +68,7 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	}
 
 	@Override
-	public void createLocalState(Transaction txn) throws DbException {
+	public void onDatabaseOpened(Transaction txn) throws DbException {
 		if (db.containsGroup(txn, localGroup.getId())) return;
 		db.addGroup(txn, localGroup);
 		// Set things up for any pre-existing contacts

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

@@ -1,6 +1,7 @@
 package org.briarproject.bramble.transport;
 
 import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.PendingContactId;
 import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.DatabaseComponent;
@@ -17,8 +18,8 @@ import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
 import org.briarproject.bramble.api.transport.KeyManager;
+import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.StreamContext;
-import org.briarproject.bramble.api.transport.TransportKeySetId;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -28,6 +29,7 @@ import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
 
+import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 import javax.inject.Inject;
 
@@ -88,29 +90,53 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 	}
 
 	@Override
-	public Map<TransportId, TransportKeySetId> addContact(Transaction txn,
+	public Map<TransportId, KeySetId> addContactWithRotationKeys(
-			ContactId c, SecretKey rootKey, long timestamp, boolean alice,
+			Transaction txn, ContactId c, SecretKey rootKey, long timestamp,
-			boolean active) throws DbException {
+			boolean alice, boolean active) throws DbException {
-		Map<TransportId, TransportKeySetId> ids = new HashMap<>();
+		Map<TransportId, KeySetId> ids = new HashMap<>();
 		for (Entry<TransportId, TransportKeyManager> e : managers.entrySet()) {
 			TransportId t = e.getKey();
 			TransportKeyManager m = e.getValue();
-			ids.put(t, m.addContact(txn, c, rootKey, timestamp, alice, active));
+			ids.put(t, m.addContactWithRotationKeys(txn, c, rootKey, timestamp,
+					alice, active));
 		}
 		return ids;
 	}
 
 	@Override
-	public void activateKeys(Transaction txn, Map<TransportId,
+	public Map<TransportId, KeySetId> addContactWithHandshakeKeys(
-			TransportKeySetId> keys) throws DbException {
+			Transaction txn, ContactId c, SecretKey rootKey, boolean alice)
-		for (Entry<TransportId, TransportKeySetId> e : keys.entrySet()) {
+			throws DbException {
+		Map<TransportId, KeySetId> ids = new HashMap<>();
+		for (Entry<TransportId, TransportKeyManager> e : managers.entrySet()) {
 			TransportId t = e.getKey();
-			TransportKeyManager m = managers.get(t);
+			TransportKeyManager m = e.getValue();
-			if (m == null) {
+			ids.put(t, m.addContactWithHandshakeKeys(txn, c, rootKey, alice));
-				if (LOG.isLoggable(INFO)) LOG.info("No key manager for " + t);
+		}
-			} else {
+		return ids;
+	}
+
+	@Override
+	public Map<TransportId, KeySetId> addPendingContact(Transaction txn,
+			PendingContactId p, SecretKey rootKey, boolean alice)
+			throws DbException {
+		Map<TransportId, KeySetId> ids = new HashMap<>();
+		for (Entry<TransportId, TransportKeyManager> e : managers.entrySet()) {
+			TransportId t = e.getKey();
+			TransportKeyManager m = e.getValue();
+			ids.put(t, m.addPendingContact(txn, p, rootKey, alice));
+		}
+		return ids;
+	}
+
+	@Override
+	public void activateKeys(Transaction txn, Map<TransportId, KeySetId> keys)
+			throws DbException {
+		for (Entry<TransportId, KeySetId> e : keys.entrySet()) {
+			withManager(e.getKey(), m -> {
 				m.activateKeys(txn, e.getValue());
-			}
+				return null;
+			});
 		}
 	}
 
@@ -120,28 +146,34 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 		return m != null && m.canSendOutgoingStreams(c);
 	}
 
+	@Override
+	public boolean canSendOutgoingStreams(PendingContactId p, TransportId t) {
+		TransportKeyManager m = managers.get(t);
+		return m != null && m.canSendOutgoingStreams(p);
+	}
+
 	@Override
 	public StreamContext getStreamContext(ContactId c, TransportId t)
 			throws DbException {
-		TransportKeyManager m = managers.get(t);
+		return withManager(t, m ->
-		if (m == null) {
+				db.transactionWithNullableResult(false, txn ->
-			if (LOG.isLoggable(INFO)) LOG.info("No key manager for " + t);
+						m.getStreamContext(txn, c)));
-			return null;
+	}
-		}
+
-		return db.transactionWithNullableResult(false, txn ->
+	@Override
-				m.getStreamContext(txn, c));
+	public StreamContext getStreamContext(PendingContactId p, TransportId t)
+			throws DbException {
+		return withManager(t, m ->
+				db.transactionWithNullableResult(false, txn ->
+						m.getStreamContext(txn, p)));
 	}
 
 	@Override
 	public StreamContext getStreamContext(TransportId t, byte[] tag)
 			throws DbException {
-		TransportKeyManager m = managers.get(t);
+		return withManager(t, m ->
-		if (m == null) {
+				db.transactionWithNullableResult(false, txn ->
-			if (LOG.isLoggable(INFO)) LOG.info("No key manager for " + t);
+						m.getStreamContext(txn, tag)));
-			return null;
-		}
-		return db.transactionWithNullableResult(false, txn ->
-				m.getStreamContext(txn, tag));
 	}
 
 	@Override
@@ -156,4 +188,20 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 			for (TransportKeyManager m : managers.values()) m.removeContact(c);
 		});
 	}
+
+	@Nullable
+	private <T> T withManager(TransportId t, ManagerTask<T> task)
+			throws DbException {
+		TransportKeyManager m = managers.get(t);
+		if (m == null) {
+			if (LOG.isLoggable(INFO)) LOG.info("No key manager for " + t);
+			return null;
+		}
+		return task.run(m);
+	}
+
+	private interface ManagerTask<T> {
+		@Nullable
+		T run(TransportKeyManager m) throws DbException;
+	}
 }

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

@@ -1,30 +0,0 @@
-package org.briarproject.bramble.transport;
-
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.transport.TransportKeySetId;
-
-class MutableKeySet {
-
-	private final TransportKeySetId keySetId;
-	private final ContactId contactId;
-	private final MutableTransportKeys transportKeys;
-
-	MutableKeySet(TransportKeySetId keySetId, ContactId contactId,
-			MutableTransportKeys transportKeys) {
-		this.keySetId = keySetId;
-		this.contactId = contactId;
-		this.transportKeys = transportKeys;
-	}
-
-	TransportKeySetId getKeySetId() {
-		return keySetId;
-	}
-
-	ContactId getContactId() {
-		return contactId;
-	}
-
-	MutableTransportKeys getTransportKeys() {
-		return transportKeys;
-	}
-}

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

@@ -0,0 +1,51 @@
+package org.briarproject.bramble.transport;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.PendingContactId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.transport.KeySetId;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.NotThreadSafe;
+
+import static org.briarproject.bramble.api.nullsafety.NullSafety.requireExactlyOneNull;
+
+@NotThreadSafe
+@NotNullByDefault
+class MutableTransportKeySet {
+
+	private final KeySetId keySetId;
+	@Nullable
+	private final ContactId contactId;
+	@Nullable
+	private final PendingContactId pendingContactId;
+	private final MutableTransportKeys keys;
+
+	MutableTransportKeySet(KeySetId keySetId, @Nullable ContactId contactId,
+			@Nullable PendingContactId pendingContactId,
+			MutableTransportKeys keys) {
+		requireExactlyOneNull(contactId, pendingContactId);
+		this.keySetId = keySetId;
+		this.contactId = contactId;
+		this.pendingContactId = pendingContactId;
+		this.keys = keys;
+	}
+
+	KeySetId getKeySetId() {
+		return keySetId;
+	}
+
+	@Nullable
+	ContactId getContactId() {
+		return contactId;
+	}
+
+	@Nullable
+	PendingContactId getPendingContactId() {
+		return pendingContactId;
+	}
+
+	MutableTransportKeys getKeys() {
+		return keys;
+	}
+}

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

@@ -1,9 +1,11 @@
 package org.briarproject.bramble.transport;
 
+import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
+import javax.annotation.Nullable;
 import javax.annotation.concurrent.NotThreadSafe;
 
 @NotThreadSafe
@@ -13,6 +15,9 @@ class MutableTransportKeys {
 	private final TransportId transportId;
 	private final MutableIncomingKeys inPrev, inCurr, inNext;
 	private final MutableOutgoingKeys outCurr;
+	@Nullable
+	private final SecretKey rootKey;
+	private final boolean alice;
 
 	MutableTransportKeys(TransportKeys k) {
 		transportId = k.getTransportId();
@@ -20,11 +25,24 @@ class MutableTransportKeys {
 		inCurr = new MutableIncomingKeys(k.getCurrentIncomingKeys());
 		inNext = new MutableIncomingKeys(k.getNextIncomingKeys());
 		outCurr = new MutableOutgoingKeys(k.getCurrentOutgoingKeys());
+		if (k.isHandshakeMode()) {
+			rootKey = k.getRootKey();
+			alice = k.isAlice();
+		} else {
+			rootKey = null;
+			alice = false;
+		}
 	}
 
 	TransportKeys snapshot() {
-		return new TransportKeys(transportId, inPrev.snapshot(),
+		if (rootKey == null) {
-				inCurr.snapshot(), inNext.snapshot(), outCurr.snapshot());
+			return new TransportKeys(transportId, inPrev.snapshot(),
+					inCurr.snapshot(), inNext.snapshot(), outCurr.snapshot());
+		} else {
+			return new TransportKeys(transportId, inPrev.snapshot(),
+					inCurr.snapshot(), inNext.snapshot(), outCurr.snapshot(),
+					rootKey, alice);
+		}
 	}
 
 	TransportId getTransportId() {
@@ -46,4 +64,18 @@ class MutableTransportKeys {
 	MutableOutgoingKeys getCurrentOutgoingKeys() {
 		return outCurr;
 	}
+
+	boolean isHandshakeMode() {
+		return rootKey != null;
+	}
+
+	SecretKey getRootKey() {
+		if (rootKey == null) throw new UnsupportedOperationException();
+		return rootKey;
+	}
+
+	boolean isAlice() {
+		if (rootKey == null) throw new UnsupportedOperationException();
+		return alice;
+	}
 }

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

@@ -1,12 +1,13 @@
 package org.briarproject.bramble.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;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.StreamContext;
-import org.briarproject.bramble.api.transport.TransportKeySetId;
 
 import javax.annotation.Nullable;
 
@@ -15,20 +16,34 @@ interface TransportKeyManager {
 
 	void start(Transaction txn) throws DbException;
 
-	TransportKeySetId addContact(Transaction txn, ContactId c,
+	KeySetId addContactWithRotationKeys(Transaction txn, ContactId c,
 			SecretKey rootKey, long timestamp, boolean alice, boolean active)
 			throws DbException;
 
-	void activateKeys(Transaction txn, TransportKeySetId k) throws DbException;
+	KeySetId addContactWithHandshakeKeys(Transaction txn, ContactId c,
+			SecretKey rootKey, boolean alice) throws DbException;
+
+	KeySetId addPendingContact(Transaction txn, PendingContactId p,
+			SecretKey rootKey, boolean alice) throws DbException;
+
+	void activateKeys(Transaction txn, KeySetId k) throws DbException;
 
 	void removeContact(ContactId c);
 
+	void removePendingContact(PendingContactId p);
+
 	boolean canSendOutgoingStreams(ContactId c);
 
+	boolean canSendOutgoingStreams(PendingContactId p);
+
 	@Nullable
 	StreamContext getStreamContext(Transaction txn, ContactId c)
 			throws DbException;
 
+	@Nullable
+	StreamContext getStreamContext(Transaction txn, PendingContactId p)
+			throws DbException;
+
 	@Nullable
 	StreamContext getStreamContext(Transaction txn, byte[] tag)
 			throws DbException;

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

@@ -2,6 +2,7 @@ package org.briarproject.bramble.transport;
 
 import org.briarproject.bramble.api.Bytes;
 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.crypto.TransportCrypto;
 import org.briarproject.bramble.api.db.DatabaseComponent;
@@ -11,9 +12,9 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.Scheduler;
+import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.StreamContext;
 import org.briarproject.bramble.api.transport.TransportKeySet;
-import org.briarproject.bramble.api.transport.TransportKeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
 import org.briarproject.bramble.transport.ReorderingWindow.Change;
 
@@ -28,10 +29,14 @@ import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.logging.Logger;
 
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.GuardedBy;
 import javax.annotation.concurrent.ThreadSafe;
 
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.nullsafety.NullSafety.requireExactlyOneNull;
 import static org.briarproject.bramble.api.transport.TransportConstants.MAX_CLOCK_DIFFERENCE;
 import static org.briarproject.bramble.api.transport.TransportConstants.PROTOCOL_VERSION;
 import static org.briarproject.bramble.api.transport.TransportConstants.TAG_LENGTH;
@@ -43,7 +48,7 @@ import static org.briarproject.bramble.util.LogUtils.logException;
 class TransportKeyManagerImpl implements TransportKeyManager {
 
 	private static final Logger LOG =
-			Logger.getLogger(TransportKeyManagerImpl.class.getName());
+			getLogger(TransportKeyManagerImpl.class.getName());
 
 	private final DatabaseComponent db;
 	private final TransportCrypto transportCrypto;
@@ -55,10 +60,16 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 	private final AtomicBoolean used = new AtomicBoolean(false);
 	private final ReentrantLock lock = new ReentrantLock();
 
-	// The following are locking: lock
+	@GuardedBy("lock")
-	private final Map<TransportKeySetId, MutableKeySet> keys = new HashMap<>();
+	private final Map<KeySetId, MutableTransportKeySet> keys = new HashMap<>();
+	@GuardedBy("lock")
 	private final Map<Bytes, TagContext> inContexts = new HashMap<>();
-	private final Map<ContactId, MutableKeySet> outContexts = new HashMap<>();
+	@GuardedBy("lock")
+	private final Map<ContactId, MutableTransportKeySet>
+			contactOutContexts = new HashMap<>();
+	@GuardedBy("lock")
+	private final Map<PendingContactId, MutableTransportKeySet>
+			pendingContactOutContexts = new HashMap<>();
 
 	TransportKeyManagerImpl(DatabaseComponent db,
 			TransportCrypto transportCrypto, Executor dbExecutor,
@@ -82,62 +93,71 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 			// Load the transport keys from the DB
 			Collection<TransportKeySet> loaded =
 					db.getTransportKeys(txn, transportId);
-			// Rotate the keys to the current time period
+			// Update the keys to the current time period
-			RotationResult rotationResult = rotateKeys(loaded, now);
+			UpdateResult updateResult = updateKeys(loaded, now);
 			// Initialise mutable state for all contacts
-			addKeys(rotationResult.current);
+			addKeys(updateResult.current);
-			// Write any rotated keys back to the DB
+			// Write any updated keys back to the DB
-			if (!rotationResult.rotated.isEmpty())
+			if (!updateResult.updated.isEmpty())
-				db.updateTransportKeys(txn, rotationResult.rotated);
+				db.updateTransportKeys(txn, updateResult.updated);
 		} finally {
 			lock.unlock();
 		}
-		// Schedule the next key rotation
+		// Schedule the next key update
-		scheduleKeyRotation(now);
+		scheduleKeyUpdate(now);
 	}
 
-	private RotationResult rotateKeys(Collection<TransportKeySet> keys,
+	private UpdateResult updateKeys(Collection<TransportKeySet> keys,
 			long now) {
-		RotationResult rotationResult = new RotationResult();
+		UpdateResult updateResult = new UpdateResult();
 		long timePeriod = now / timePeriodLength;
 		for (TransportKeySet ks : keys) {
 			TransportKeys k = ks.getKeys();
-			TransportKeys k1 = transportCrypto.rotateTransportKeys(k,
+			TransportKeys k1 = transportCrypto.updateTransportKeys(k,
 					timePeriod);
 			TransportKeySet ks1 = new TransportKeySet(ks.getKeySetId(),
-					ks.getContactId(), k1);
+					ks.getContactId(), null, k1);
 			if (k1.getTimePeriod() > k.getTimePeriod())
-				rotationResult.rotated.add(ks1);
+				updateResult.updated.add(ks1);
-			rotationResult.current.add(ks1);
+			updateResult.current.add(ks1);
 		}
-		return rotationResult;
+		return updateResult;
 	}
 
-	// Locking: lock
+	@GuardedBy("lock")
 	private void addKeys(Collection<TransportKeySet> keys) {
 		for (TransportKeySet ks : keys) {
 			addKeys(ks.getKeySetId(), ks.getContactId(),
+					ks.getPendingContactId(),
 					new MutableTransportKeys(ks.getKeys()));
 		}
 	}
 
-	// Locking: lock
+	@GuardedBy("lock")
-	private void addKeys(TransportKeySetId keySetId, ContactId contactId,
+	private void addKeys(KeySetId keySetId, @Nullable ContactId contactId,
-			MutableTransportKeys m) {
+			@Nullable PendingContactId pendingContactId,
-		MutableKeySet ks = new MutableKeySet(keySetId, contactId, m);
+			MutableTransportKeys keys) {
-		keys.put(keySetId, ks);
+		requireExactlyOneNull(contactId, pendingContactId);
-		encodeTags(keySetId, contactId, m.getPreviousIncomingKeys());
+		MutableTransportKeySet ks = new MutableTransportKeySet(keySetId,
-		encodeTags(keySetId, contactId, m.getCurrentIncomingKeys());
+				contactId, pendingContactId, keys);
-		encodeTags(keySetId, contactId, m.getNextIncomingKeys());
+		this.keys.put(keySetId, ks);
+		boolean handshakeMode = keys.isHandshakeMode();
+		encodeTags(keySetId, contactId, pendingContactId,
+				keys.getPreviousIncomingKeys(), handshakeMode);
+		encodeTags(keySetId, contactId, pendingContactId,
+				keys.getCurrentIncomingKeys(), handshakeMode);
+		encodeTags(keySetId, contactId, pendingContactId,
+				keys.getNextIncomingKeys(), handshakeMode);
 		considerReplacingOutgoingKeys(ks);
 	}
 
-	// Locking: lock
+	@GuardedBy("lock")
-	private void encodeTags(TransportKeySetId keySetId, ContactId contactId,
+	private void encodeTags(KeySetId keySetId, @Nullable ContactId contactId,
-			MutableIncomingKeys inKeys) {
+			@Nullable PendingContactId pendingContactId,
+			MutableIncomingKeys inKeys, boolean handshakeMode) {
 		for (long streamNumber : inKeys.getWindow().getUnseen()) {
-			TagContext tagCtx =
+			TagContext tagCtx = new TagContext(keySetId, contactId,
-					new TagContext(keySetId, contactId, inKeys, streamNumber);
+					pendingContactId, inKeys, streamNumber, handshakeMode);
 			byte[] tag = new byte[TAG_LENGTH];
 			transportCrypto.encodeTag(tag, inKeys.getTagKey(), PROTOCOL_VERSION,
 					streamNumber);
@@ -145,27 +165,41 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 		}
 	}
 
-	// Locking: lock
+	@GuardedBy("lock")
-	private void considerReplacingOutgoingKeys(MutableKeySet ks) {
+	private void considerReplacingOutgoingKeys(MutableTransportKeySet ks) {
-		// Use the active outgoing keys with the highest key set ID
+		// Use the active outgoing keys with the highest key set ID, preferring
-		if (ks.getTransportKeys().getCurrentOutgoingKeys().isActive()) {
+		// rotation keys to handshake keys
-			MutableKeySet old = outContexts.get(ks.getContactId());
+		if (ks.getKeys().getCurrentOutgoingKeys().isActive()) {
-			if (old == null ||
+			MutableTransportKeySet old = getOutgoingKeySet(ks.getContactId(),
+					ks.getPendingContactId());
+			if (old == null || (old.getKeys().isHandshakeMode() &&
+					!ks.getKeys().isHandshakeMode()) ||
 					old.getKeySetId().getInt() < ks.getKeySetId().getInt()) {
-				outContexts.put(ks.getContactId(), ks);
+				if (ks.getContactId() == null)
+					pendingContactOutContexts.put(ks.getPendingContactId(), ks);
+				else contactOutContexts.put(ks.getContactId(), ks);
 			}
 		}
 	}
 
-	private void scheduleKeyRotation(long now) {
+	@GuardedBy("lock")
-		long delay = timePeriodLength - now % timePeriodLength;
+	@Nullable
-		scheduler.schedule((Runnable) this::rotateKeys, delay, MILLISECONDS);
+	private MutableTransportKeySet getOutgoingKeySet(@Nullable ContactId c,
+			@Nullable PendingContactId p) {
+		requireExactlyOneNull(c, p);
+		if (c == null) return pendingContactOutContexts.get(p);
+		else return contactOutContexts.get(c);
 	}
 
-	private void rotateKeys() {
+	private void scheduleKeyUpdate(long now) {
+		long delay = timePeriodLength - now % timePeriodLength;
+		scheduler.schedule((Runnable) this::updateKeys, delay, MILLISECONDS);
+	}
+
+	private void updateKeys() {
 		dbExecutor.execute(() -> {
 			try {
-				db.transaction(false, this::rotateKeys);
+				db.transaction(false, this::updateKeys);
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 			}
@@ -173,7 +207,7 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 	}
 
 	@Override
-	public TransportKeySetId addContact(Transaction txn, ContactId c,
+	public KeySetId addContactWithRotationKeys(Transaction txn, ContactId c,
 			SecretKey rootKey, long timestamp, boolean alice, boolean active)
 			throws DbException {
 		lock.lock();
@@ -181,15 +215,15 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 			// Work out what time period the timestamp belongs to
 			long timePeriod = timestamp / timePeriodLength;
 			// Derive the transport keys
-			TransportKeys k = transportCrypto.deriveTransportKeys(transportId,
+			TransportKeys k = transportCrypto.deriveRotationKeys(transportId,
 					rootKey, timePeriod, alice, active);
-			// Rotate the keys to the current time period if necessary
+			// Update the keys to the current time period if necessary
 			timePeriod = clock.currentTimeMillis() / timePeriodLength;
-			k = transportCrypto.rotateTransportKeys(k, timePeriod);
+			k = transportCrypto.updateTransportKeys(k, timePeriod);
 			// Write the keys back to the DB
-			TransportKeySetId keySetId = db.addTransportKeys(txn, c, k);
+			KeySetId keySetId = db.addTransportKeys(txn, c, k);
 			// Initialise mutable state for the contact
-			addKeys(keySetId, c, new MutableTransportKeys(k));
+			addKeys(keySetId, c, null, new MutableTransportKeys(k));
 			return keySetId;
 		} finally {
 			lock.unlock();
@@ -197,13 +231,52 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 	}
 
 	@Override
-	public void activateKeys(Transaction txn, TransportKeySetId k)
+	public KeySetId addContactWithHandshakeKeys(Transaction txn, ContactId c,
-			throws DbException {
+			SecretKey rootKey, boolean alice) throws DbException {
 		lock.lock();
 		try {
-			MutableKeySet ks = keys.get(k);
+			// Work out what time period we're in
+			long timePeriod = clock.currentTimeMillis() / timePeriodLength;
+			// Derive the transport keys
+			TransportKeys k = transportCrypto.deriveHandshakeKeys(transportId,
+					rootKey, timePeriod, alice);
+			// Write the keys back to the DB
+			KeySetId keySetId = db.addTransportKeys(txn, c, k);
+			// Initialise mutable state for the contact
+			addKeys(keySetId, c, null, new MutableTransportKeys(k));
+			return keySetId;
+		} finally {
+			lock.unlock();
+		}
+	}
+
+	@Override
+	public KeySetId addPendingContact(Transaction txn, PendingContactId p,
+			SecretKey rootKey, boolean alice) throws DbException {
+		lock.lock();
+		try {
+			// Work out what time period we're in
+			long timePeriod = clock.currentTimeMillis() / timePeriodLength;
+			// Derive the transport keys
+			TransportKeys k = transportCrypto.deriveHandshakeKeys(transportId,
+					rootKey, timePeriod, alice);
+			// Write the keys back to the DB
+			KeySetId keySetId = db.addTransportKeys(txn, p, k);
+			// Initialise mutable state for the pending contact
+			addKeys(keySetId, null, p, new MutableTransportKeys(k));
+			return keySetId;
+		} finally {
+			lock.unlock();
+		}
+	}
+
+	@Override
+	public void activateKeys(Transaction txn, KeySetId k) throws DbException {
+		lock.lock();
+		try {
+			MutableTransportKeySet ks = keys.get(k);
 			if (ks == null) throw new IllegalArgumentException();
-			MutableTransportKeys m = ks.getTransportKeys();
+			MutableTransportKeys m = ks.getKeys();
 			m.getCurrentOutgoingKeys().activate();
 			considerReplacingOutgoingKeys(ks);
 			db.setTransportKeysActive(txn, m.getTransportId(), k);
@@ -218,13 +291,29 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 		try {
 			// Remove mutable state for the contact
 			Iterator<TagContext> it = inContexts.values().iterator();
-			while (it.hasNext()) if (it.next().contactId.equals(c)) it.remove();
+			while (it.hasNext())
-			outContexts.remove(c);
+				if (c.equals(it.next().contactId)) it.remove();
-			Iterator<MutableKeySet> it1 = keys.values().iterator();
+			contactOutContexts.remove(c);
-			while (it1.hasNext()) {
+			Iterator<MutableTransportKeySet> it1 = keys.values().iterator();
-				ContactId c1 = it1.next().getContactId();
+			while (it1.hasNext())
-				if (c1 != null && c1.equals(c)) it1.remove();
+				if (c.equals(it1.next().getContactId())) it1.remove();
-			}
+		} finally {
+			lock.unlock();
+		}
+	}
+
+	@Override
+	public void removePendingContact(PendingContactId p) {
+		lock.lock();
+		try {
+			// Remove mutable state for the pending contact
+			Iterator<TagContext> it = inContexts.values().iterator();
+			while (it.hasNext())
+				if (p.equals(it.next().pendingContactId)) it.remove();
+			pendingContactOutContexts.remove(p);
+			Iterator<MutableTransportKeySet> it1 = keys.values().iterator();
+			while (it1.hasNext())
+				if (p.equals(it1.next().getPendingContactId())) it1.remove();
 		} finally {
 			lock.unlock();
 		}
@@ -232,12 +321,21 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 
 	@Override
 	public boolean canSendOutgoingStreams(ContactId c) {
+		return canSendOutgoingStreams(c, null);
+	}
+
+	@Override
+	public boolean canSendOutgoingStreams(PendingContactId p) {
+		return canSendOutgoingStreams(null, p);
+	}
+
+	private boolean canSendOutgoingStreams(@Nullable ContactId c,
+			@Nullable PendingContactId p) {
 		lock.lock();
 		try {
-			MutableKeySet ks = outContexts.get(c);
+			MutableTransportKeySet ks = getOutgoingKeySet(c, p);
 			if (ks == null) return false;
-			MutableOutgoingKeys outKeys =
+			MutableOutgoingKeys outKeys = ks.getKeys().getCurrentOutgoingKeys();
-					ks.getTransportKeys().getCurrentOutgoingKeys();
 			if (!outKeys.isActive()) throw new AssertionError();
 			return outKeys.getStreamCounter() <= MAX_32_BIT_UNSIGNED;
 		} finally {
@@ -248,19 +346,32 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 	@Override
 	public StreamContext getStreamContext(Transaction txn, ContactId c)
 			throws DbException {
+		return getStreamContext(txn, c, null);
+	}
+
+	@Override
+	public StreamContext getStreamContext(Transaction txn, PendingContactId p)
+			throws DbException {
+		return getStreamContext(txn, null, p);
+	}
+
+	@Nullable
+	private StreamContext getStreamContext(Transaction txn,
+			@Nullable ContactId c, @Nullable PendingContactId p)
+			throws DbException {
 		lock.lock();
 		try {
 			// Look up the outgoing keys for the contact
-			MutableKeySet ks = outContexts.get(c);
+			MutableTransportKeySet ks = getOutgoingKeySet(c, p);
 			if (ks == null) return null;
-			MutableOutgoingKeys outKeys =
+			MutableTransportKeys keys = ks.getKeys();
-					ks.getTransportKeys().getCurrentOutgoingKeys();
+			MutableOutgoingKeys outKeys = keys.getCurrentOutgoingKeys();
 			if (!outKeys.isActive()) throw new AssertionError();
 			if (outKeys.getStreamCounter() > MAX_32_BIT_UNSIGNED) return null;
 			// Create a stream context
-			StreamContext ctx = new StreamContext(c, transportId,
+			StreamContext ctx = new StreamContext(c, p, transportId,
 					outKeys.getTagKey(), outKeys.getHeaderKey(),
-					outKeys.getStreamCounter());
+					outKeys.getStreamCounter(), keys.isHandshakeMode());
 			// Increment the stream counter and write it back to the DB
 			outKeys.incrementStreamCounter();
 			db.incrementStreamCounter(txn, transportId, ks.getKeySetId());
@@ -280,9 +391,10 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 			if (tagCtx == null) return null;
 			MutableIncomingKeys inKeys = tagCtx.inKeys;
 			// Create a stream context
-			StreamContext ctx = new StreamContext(tagCtx.contactId, transportId,
+			StreamContext ctx = new StreamContext(tagCtx.contactId,
+					tagCtx.pendingContactId, transportId,
 					inKeys.getTagKey(), inKeys.getHeaderKey(),
-					tagCtx.streamNumber);
+					tagCtx.streamNumber, tagCtx.handshakeMode);
 			// Update the reordering window
 			ReorderingWindow window = inKeys.getWindow();
 			Change change = window.setSeen(tagCtx.streamNumber);
@@ -292,7 +404,8 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 				transportCrypto.encodeTag(addTag, inKeys.getTagKey(),
 						PROTOCOL_VERSION, streamNumber);
 				TagContext tagCtx1 = new TagContext(tagCtx.keySetId,
-						tagCtx.contactId, inKeys, streamNumber);
+						tagCtx.contactId, tagCtx.pendingContactId, inKeys,
+						streamNumber, tagCtx.handshakeMode);
 				inContexts.put(new Bytes(addTag), tagCtx1);
 			}
 			// Remove tags for any stream numbers removed from the window
@@ -308,9 +421,9 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 					inKeys.getTimePeriod(), window.getBase(),
 					window.getBitmap());
 			// If the outgoing keys are inactive, activate them
-			MutableKeySet ks = keys.get(tagCtx.keySetId);
+			MutableTransportKeySet ks = keys.get(tagCtx.keySetId);
 			MutableOutgoingKeys outKeys =
-					ks.getTransportKeys().getCurrentOutgoingKeys();
+					ks.getKeys().getCurrentOutgoingKeys();
 			if (!outKeys.isActive()) {
 				LOG.info("Activating outgoing keys");
 				outKeys.activate();
@@ -323,51 +436,62 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 		}
 	}
 
-	private void rotateKeys(Transaction txn) throws DbException {
+	private void updateKeys(Transaction txn) throws DbException {
 		long now = clock.currentTimeMillis();
 		lock.lock();
 		try {
-			// Rotate the keys to the current time period
+			// Update the keys to the current time period
 			Collection<TransportKeySet> snapshot = new ArrayList<>(keys.size());
-			for (MutableKeySet ks : keys.values()) {
+			for (MutableTransportKeySet ks : keys.values()) {
 				snapshot.add(new TransportKeySet(ks.getKeySetId(),
-						ks.getContactId(), ks.getTransportKeys().snapshot()));
+						ks.getContactId(), ks.getPendingContactId(),
+						ks.getKeys().snapshot()));
 			}
-			RotationResult rotationResult = rotateKeys(snapshot, now);
+			UpdateResult updateResult = updateKeys(snapshot, now);
 			// Rebuild the mutable state for all contacts
 			inContexts.clear();
-			outContexts.clear();
+			contactOutContexts.clear();
+			pendingContactOutContexts.clear();
 			keys.clear();
-			addKeys(rotationResult.current);
+			addKeys(updateResult.current);
-			// Write any rotated keys back to the DB
+			// Write any updated keys back to the DB
-			if (!rotationResult.rotated.isEmpty())
+			if (!updateResult.updated.isEmpty())
-				db.updateTransportKeys(txn, rotationResult.rotated);
+				db.updateTransportKeys(txn, updateResult.updated);
 		} finally {
 			lock.unlock();
 		}
-		// Schedule the next key rotation
+		// Schedule the next key update
-		scheduleKeyRotation(now);
+		scheduleKeyUpdate(now);
 	}
 
 	private static class TagContext {
 
-		private final TransportKeySetId keySetId;
+		private final KeySetId keySetId;
+		@Nullable
 		private final ContactId contactId;
+		@Nullable
+		private final PendingContactId pendingContactId;
 		private final MutableIncomingKeys inKeys;
 		private final long streamNumber;
+		private final boolean handshakeMode;
 
-		private TagContext(TransportKeySetId keySetId, ContactId contactId,
+		private TagContext(KeySetId keySetId, @Nullable ContactId contactId,
-				MutableIncomingKeys inKeys, long streamNumber) {
+				@Nullable PendingContactId pendingContactId,
+				MutableIncomingKeys inKeys, long streamNumber,
+				boolean handshakeMode) {
+			requireExactlyOneNull(contactId, pendingContactId);
 			this.keySetId = keySetId;
 			this.contactId = contactId;
+			this.pendingContactId = pendingContactId;
 			this.inKeys = inKeys;
 			this.streamNumber = streamNumber;
+			this.handshakeMode = handshakeMode;
 		}
 	}
 
-	private static class RotationResult {
+	private static class UpdateResult {
 
 		private final Collection<TransportKeySet> current = new ArrayList<>();
-		private final Collection<TransportKeySet> rotated = new ArrayList<>();
+		private final Collection<TransportKeySet> updated = new ArrayList<>();
 	}
 }

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

@@ -12,10 +12,10 @@ import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager.OpenDatabaseHook;
 import org.briarproject.bramble.api.lifecycle.Service;
 import org.briarproject.bramble.api.lifecycle.ServiceException;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.sync.Client;
 import org.briarproject.bramble.api.sync.ClientId;
 import org.briarproject.bramble.api.sync.Group;
 import org.briarproject.bramble.api.sync.Group.Visibility;
@@ -53,8 +53,8 @@ import static org.briarproject.bramble.versioning.ClientVersioningConstants.MSG_
 import static org.briarproject.bramble.versioning.ClientVersioningConstants.MSG_KEY_UPDATE_VERSION;
 
 @NotNullByDefault
-class ClientVersioningManagerImpl implements ClientVersioningManager, Client,
+class ClientVersioningManagerImpl implements ClientVersioningManager,
-		Service, ContactHook, IncomingMessageHook {
+		Service, OpenDatabaseHook, ContactHook, IncomingMessageHook {
 
 	private final DatabaseComponent db;
 	private final ClientHelper clientHelper;
@@ -124,7 +124,7 @@ class ClientVersioningManagerImpl implements ClientVersioningManager, Client,
 	}
 
 	@Override
-	public void createLocalState(Transaction txn) throws DbException {
+	public void onDatabaseOpened(Transaction txn) throws DbException {
 		if (db.containsGroup(txn, localGroup.getId())) return;
 		db.addGroup(txn, localGroup);
 		// Set things up for any pre-existing contacts

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

@@ -34,7 +34,7 @@ public class VersioningModule {
 			ClientVersioningManagerImpl clientVersioningManager,
 			LifecycleManager lifecycleManager, ContactManager contactManager,
 			ValidationManager validationManager) {
-		lifecycleManager.registerClient(clientVersioningManager);
+		lifecycleManager.registerOpenDatabaseHook(clientVersioningManager);
 		lifecycleManager.registerService(clientVersioningManager);
 		contactManager.registerContactHook(clientVersioningManager);
 		validationManager.registerIncomingMessageHook(CLIENT_ID, MAJOR_VERSION,