Decouple poller from plugin manager.

Generate and store handshake key pair at startup if necessary

Closes #1538

See merge request briar/briar!1082

.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

@@ -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/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:shared:26.3.2:shared-26.3.2.jar:ddd80dcf21905018b7c0583ba72b7282f446084d4952422609a09fbf8237ef71',
-        'com.android.tools.analytics-library:tracker:26.3.2:tracker-26.3.2.jar:28c575d2d1af003e96d7b375a668ee10b2673a2dd0f6438750aa8c3b42e7d0ad',
-        'com.android.tools.build:apksig:3.3.2:apksig-3.3.2.jar:84c4aaa20127c6c1fe6bdd334b3f5df71f54ad080be9029c8a10f43b6a908acd',
-        'com.android.tools.build:apkzlib:3.3.2:apkzlib-3.3.2.jar:d34e523278e5dff565eba3ef3c089d515b2b5cc7b47dc77e2f3465e5e47176ac',
-        'com.android.tools.build:builder-model:3.3.2:builder-model-3.3.2.jar:055e3db0ecee9e06b9f024034999a29cd92cb1885207b37542126bd8bcc57f46',
-        'com.android.tools.build:builder-test-api:3.3.2:builder-test-api-3.3.2.jar:0b2e4cd7615bbcad14a3c91fe45ae26693508d06e40ba06c5968b8bc24416618',
-        'com.android.tools.build:builder:3.3.2:builder-3.3.2.jar:65649704da7aef0487235fd326f0f2e99ed5cf958e80f204496e6e08a42bd9f5',
-        'com.android.tools.build:gradle-api:3.3.2:gradle-api-3.3.2.jar:3cbd47e41bb70330dd72ec2c9fe51e6173554b484a03829b5a2de9e00841e040',
-        'com.android.tools.build:manifest-merger:26.3.2:manifest-merger-26.3.2.jar:05c4a6d8b02fb9f08744876477d0a68547c03a8a9069b1f086684fa04af97c33',
-        'com.android.tools.ddms:ddmlib:26.3.2:ddmlib-26.3.2.jar:d248da8a563d6e46d2c7ebbf371a4877e00510f4ca763c0bb272d5a281bf8b85',
-        'com.android.tools.external.com-intellij:intellij-core:26.3.2:intellij-core-26.3.2.jar:6c5ecc968230e9f4dcd0fef28885379feace1f0cd8130de6f61d649c86139bf3',
-        'com.android.tools.external.com-intellij:kotlin-compiler:26.3.2:kotlin-compiler-26.3.2.jar:1007d9b07ccb49cd8eaf30fda10ed4681d4714f2f9ab2ecda39b4e539cc51bbe',
-        'com.android.tools.external.org-jetbrains:uast:26.3.2:uast-26.3.2.jar:5d1833e562ea4f38a89708dfde695f0a162cbd39d003d3dde818c3fdc2b05317',
-        'com.android.tools.layoutlib:layoutlib-api:26.3.2:layoutlib-api-26.3.2.jar:d7e61e874ab95f5c350dd38b6a95b5c9dbe0083a02001884264cdb390cb255b8',
-        'com.android.tools.lint:lint-api:26.3.2:lint-api-26.3.2.jar:5867dfd7fb4a4e161a816a5d29d045f9b542d34594c00a1efec46fb4cd0e1033',
-        'com.android.tools.lint:lint-checks:26.3.2:lint-checks-26.3.2.jar:4b163b9c93790d2771e92ba8de58a0d9e0671ffcf2ccef3cf496efd442e27517',
-        'com.android.tools.lint:lint-gradle-api:26.3.2:lint-gradle-api-26.3.2.jar:54cb282e0c054f9bed3f51302ce08b003c8ab7961dfd5a4f6de26c23cc23062f',
-        'com.android.tools.lint:lint-gradle:26.3.2:lint-gradle-26.3.2.jar:bb139615f4ce97d42cc394b9389b49b76a6eb85be6785a5d272991543b519013',
-        'com.android.tools.lint:lint:26.3.2:lint-26.3.2.jar:ef7b369f8a56a92ccb0f4c1c357666b9339e4a711a9d84747d446441746cfe4e',
-        'com.android.tools:annotations:26.3.2:annotations-26.3.2.jar:5bcce8e98b6a2f5ccf13ebcefd8f734e0b35f8b19e456575665631442ce1f7a1',
-        'com.android.tools:common:26.3.2:common-26.3.2.jar:d9f8e7f0669e9a701568e3db6a87c89cf12d8fa6811c9991e969f950215ecfac',
-        'com.android.tools:dvlib:26.3.2:dvlib-26.3.2.jar:d84aad56161c7773579303d69714ded6897c64c6ddfd7d456e453231e4dfe811',
-        'com.android.tools:repository:26.3.2:repository-26.3.2.jar:da611eeb06e9ab8750d25b9e2901e10db8e5ec6304eb4c8b7103d39e0921ea40',
-        'com.android.tools:sdk-common:26.3.2:sdk-common-26.3.2.jar:82823a3bf25e64fac33a286490f0cf5ac50c2cdb3c540149b030896bb44bf96c',
-        'com.android.tools:sdklib:26.3.2:sdklib-26.3.2.jar:424d15492af67321900963238646d27495ab60de2a5b19e6a416963bc5d6932b',
+        'com.android.tools.analytics-library:protos:26.4.0:protos-26.4.0.jar:ad760915586797d39319f402837b378bff3bb4ed583e3e0c48c965631fb2135f',
+        'com.android.tools.analytics-library:shared:26.4.0:shared-26.4.0.jar:1332106a905d48909c81268c9e414946de3e83487db394c6073b0a9b5c3d0ed2',
+        'com.android.tools.analytics-library:tracker:26.4.0:tracker-26.4.0.jar:d0020cfbfd4cd75935f2972d6a24089840d4a10df6f3ef2a796093217dd37796',
+        'com.android.tools.build:apksig:3.4.0:apksig-3.4.0.jar:91d5a1866139c69756280355a6f61b4d619d0516841580114f45a10f2177327e',
+        'com.android.tools.build:apkzlib:3.4.0:apkzlib-3.4.0.jar:8653c85f5fdf1dde840e8b8af7396aeb79c34b66e541b5860059616006535592',
+        'com.android.tools.build:builder-model:3.4.0:builder-model-3.4.0.jar:a88f138124a9f016a70bcb4760359a502f65c7deed56507ee4014f4dd9ea853b',
+        'com.android.tools.build:builder-test-api:3.4.0:builder-test-api-3.4.0.jar:31089ab1ec19ca7687a010867d2f3807513c805b8226979706f4247b5d4df26f',
+        'com.android.tools.build:builder:3.4.0:builder-3.4.0.jar:476221b5203a7f50089bf185ed95000a34b6f5020ef0a17815afd58606922679',
+        'com.android.tools.build:gradle-api:3.4.0:gradle-api-3.4.0.jar:215eca38f6719213c2f492b4d622cdd11676c66c9871f8a2aed0c66d00175628',
+        'com.android.tools.build:manifest-merger:26.4.0:manifest-merger-26.4.0.jar:29e45e690dedd165035e97c21c2ca94d0bd4ec16b6b210daa26669a582b6f220',
+        'com.android.tools.ddms:ddmlib:26.4.0:ddmlib-26.4.0.jar:93f56fe4630c3166adbd6c51d7bb602d96abb91b07ba5b1165fdcd071e88c940',
+        '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:26.4.0:kotlin-compiler-26.4.0.jar:dd1fe225c31a0e012dc025336363a5b783e2c5c20ffb69e77f8f57e89420d998',
+        'com.android.tools.external.org-jetbrains:uast:26.4.0:uast-26.4.0.jar:f25f3285b775a983327583ff6584dea54e447813ef69e0ce08b05a45b5f4aab0',
+        'com.android.tools.layoutlib:layoutlib-api:26.4.0:layoutlib-api-26.4.0.jar:52128f5cf293b224072be361919bfd416e59480ab7264ddcdbbf046b0d7a12e3',
+        'com.android.tools.lint:lint-api:26.4.0:lint-api-26.4.0.jar:fdb8fca8ae4c254f438338d03d72605e00ed106f2d5550405af41ca1c8509401',
+        'com.android.tools.lint:lint-checks:26.4.0:lint-checks-26.4.0.jar:4ff52d40488cd3e22b9c6b2eb67784e0c3269d0b42ef9d17689cd75a7b2bceb4',
+        'com.android.tools.lint:lint-gradle-api:26.4.0:lint-gradle-api-26.4.0.jar:714b7a85c7d2aa10daeab16e969fe7530c659d0728a7f24021da456870418d0f',
+        'com.android.tools.lint:lint-gradle:26.4.0:lint-gradle-26.4.0.jar:b8c130d273f522388734457e1b96790f41528fcec6fda9e8eaa4e4d95a07cfbb',
+        'com.android.tools.lint:lint:26.4.0:lint-26.4.0.jar:83aa062fb0405b60ed358d858c8c2955e1bae44a455b498068c6a60988755f00',
+        'com.android.tools:annotations:26.4.0:annotations-26.4.0.jar:a7955b8e19c3a2a861d6faa43a58b7c0d46ea9112188ee3e235c6f9f439ecc1a',
+        'com.android.tools:common:26.4.0:common-26.4.0.jar:ea40b94b3c1284ea7700f011388e2906a8363a66abd902891722b3c557984852',
+        'com.android.tools:dvlib:26.4.0:dvlib-26.4.0.jar:23af89c535b01ba36ceed1b6b309b672814eba624e643cd7dedf0519edad50cc',
+        'com.android.tools:repository:26.4.0:repository-26.4.0.jar:3d1763ab46199374dc6d94129bba11c70f1d5857e2c81a3ac4898abca40b176b',
+        'com.android.tools:sdk-common:26.4.0:sdk-common-26.4.0.jar:78a522525b30ffc6b7bf1299c831d24ce385f68a9f4878f8f752e9baefa31b0f',
+        '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-producers:2.19:dagger-producers-2.19.jar:a17663abe0fc38b676026950907d4c5f5e2bf338375415861eaff6e3bdb0b768',
-        'com.google.dagger:dagger-spi:2.19:dagger-spi-2.19.jar:e7a6379d82c841f6aac2866948ad1eed716528707814602842a8d844ce04e2e1',
-        'com.google.dagger:dagger:2.19:dagger-2.19.jar:514b6f1e0727c6572e1d65cb27e4ae668b7aeaeb93a29515182965265b609939',
+        'com.google.dagger:dagger-compiler:2.22.1:dagger-compiler-2.22.1.jar:e5f28302cbe70a79d3620cddebfb8ec0736814f3980ffe1e673bfe3342f507d3',
+        'com.google.dagger:dagger-producers:2.22.1:dagger-producers-2.22.1.jar:f834a0082014213a68ff06a0f048d750178d02196c58b0b15beb367d32b97e35',
+        'com.google.dagger:dagger-spi:2.22.1:dagger-spi-2.22.1.jar:4b0b922793b3bcb91b99fabb75dba77c68afd7ae4c5f0c4fd6ba681f0a291c7d',
+        '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:httpcore:4.4.5:httpcore-4.4.5.jar:64d5453874cab7e40a7065cb01a9a9ca1053845a9786b478878b679e0580cec3',
-        'org.apache.httpcomponents:httpmime:4.5.2:httpmime-4.5.2.jar:231a3f7e4962053db2be8461d5422e68fc458a3a7dd7d8ada803a348e21f8f07',
+        'org.apache.httpcomponents:httpclient:4.5.6:httpclient-4.5.6.jar:c03f813195e7a80e3608d0ddd8da80b21696a4c92a6a2298865bf149071551c7',
+        'org.apache.httpcomponents:httpcore:4.4.10:httpcore-4.4.10.jar:78ba1096561957db1b55200a159b648876430342d15d461277e62360da19f6fd',
+        '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/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/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.
-	 */
-	boolean isValidRemoteContactLink(String link);
-
-	/**
-	 * Requests a new contact to be added via the given {@code link}.
+	 * Creates a {@link PendingContact} from the given handshake link and
+	 * alias, adds it to the database and returns it.
 	 *
-	 * @param link The link received from the contact we want to add.
-	 * @param alias The alias the user has given this contact.
-	 * @return A PendingContact representing the contact to be added.
+	 * @param link The handshake link received from the contact we want to add
+	 * @param alias The alias the user has given this contact
+	 * @return A PendingContact representing the contact to be added
+	 * @throws UnsupportedVersionException If the link uses a format version
+	 * that is not supported
+	 * @throws FormatException If the link is invalid
 	 */
-	PendingContact 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
-	 * {@link PendingContactState FAILED}.
+	 * Removes a {@link PendingContact}.
 	 */
-	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/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/db/DatabaseComponent.java

@@ -7,7 +7,7 @@ import org.briarproject.bramble.api.contact.PendingContactId;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
-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;
@@ -128,9 +128,9 @@ public interface DatabaseComponent {
 			HandshakeKeys k) throws DbException;
 
 	/**
-	 * Stores a local pseudonym.
+	 * Stores an identity.
 	 */
-	void addLocalAuthor(Transaction txn, LocalAuthor a) throws DbException;
+	void addIdentity(Transaction txn, Identity i) throws DbException;
 
 	/**
 	 * Stores a local message.
@@ -174,12 +174,12 @@ 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)
-			throws DbException;
+	boolean containsIdentity(Transaction txn, AuthorId a) throws DbException;
 
 	/**
 	 * Returns true if the database contains the given pending contact.
@@ -317,18 +317,18 @@ public interface DatabaseComponent {
 			throws DbException;
 
 	/**
-	 * Returns the local pseudonym with the given ID.
+	 * Returns the identity for the local pseudonym with the given ID.
 	 * <p/>
 	 * Read-only.
 	 */
-	LocalAuthor getLocalAuthor(Transaction txn, AuthorId a) throws DbException;
+	Identity getIdentity(Transaction txn, AuthorId a) throws DbException;
 
 	/**
-	 * Returns all local pseudonyms.
+	 * Returns the identities for all local pseudonyms.
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<LocalAuthor> getLocalAuthors(Transaction txn) throws DbException;
+	Collection<Identity> getIdentities(Transaction txn) throws DbException;
 
 	/**
 	 * Returns the message with the given ID.
@@ -559,9 +559,9 @@ public interface DatabaseComponent {
 			HandshakeKeySetId k) throws DbException;
 
 	/**
-	 * Removes a local pseudonym (and all associated state) from the database.
+	 * Removes an identity (and all associated state) from the database.
 	 */
-	void removeLocalAuthor(Transaction txn, AuthorId a) throws DbException;
+	void removeIdentity(Transaction txn, AuthorId a) throws DbException;
 
 	/**
 	 * Removes a message (and all associated state) from the database.
@@ -619,6 +619,12 @@ public interface DatabaseComponent {
 	void addMessageDependencies(Transaction txn, Message dependent,
 			Collection<MessageId> dependencies) throws DbException;
 
+	/**
+	 * Sets the handshake key pair for the identity with the given ID.
+	 */
+	void setHandshakeKeyPair(Transaction txn, AuthorId local, byte[] publicKey,
+			byte[] privateKey) throws DbException;
+
 	/**
 	 * Sets the reordering window for the given transport key set in the given
 	 * time period.

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/AuthorFactory.java

@@ -18,14 +18,7 @@ public interface AuthorFactory {
 
 	/**
 	 * Creates a local author with the current format version and the given
-	 * name and keys.
+	 * name.
 	 */
-	LocalAuthor createLocalAuthor(String name, byte[] publicKey,
-			byte[] privateKey);
-
-	/**
-	 * Creates a local author with the given format version, name and keys.
-	 */
-	LocalAuthor createLocalAuthor(int formatVersion, String name,
-			byte[] publicKey, byte[] privateKey);
+	LocalAuthor createLocalAuthor(String name);
 }

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

@@ -0,0 +1,96 @@
+package org.briarproject.bramble.api.identity;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.util.Arrays;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.Immutable;
+
+import static org.briarproject.bramble.api.crypto.CryptoConstants.MAX_AGREEMENT_PUBLIC_KEY_BYTES;
+
+@Immutable
+@NotNullByDefault
+public class Identity {
+
+	private final LocalAuthor localAuthor;
+	@Nullable
+	private final byte[] handshakePublicKey, handshakePrivateKey;
+	private final long created;
+
+	public Identity(LocalAuthor localAuthor,
+			@Nullable byte[] handshakePublicKey,
+			@Nullable byte[] handshakePrivateKey, long created) {
+		if (handshakePublicKey != null) {
+			int keyLength = handshakePublicKey.length;
+			if (keyLength == 0 || keyLength > MAX_AGREEMENT_PUBLIC_KEY_BYTES)
+				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 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 identity was created, in milliseconds since the
+	 * Unix epoch.
+	 */
+	public long getTimeCreated() {
+		return created;
+	}
+
+	@Override
+	public int hashCode() {
+		return localAuthor.getId().hashCode();
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if (o instanceof Identity) {
+			Identity i = (Identity) o;
+			return created == i.created &&
+					localAuthor.equals(i.localAuthor) &&
+					Arrays.equals(handshakePublicKey, i.handshakePublicKey) &&
+					Arrays.equals(handshakePrivateKey, i.handshakePrivateKey);
+		}
+		return false;
+	}
+}

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

@@ -1,30 +1,29 @@
 package org.briarproject.bramble.api.identity;
 
 import org.briarproject.bramble.api.crypto.CryptoExecutor;
+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
-	 * not stored until {@link #storeLocalAuthor()} is called.
+	 * Registers the given identity with the manager. This method should be
+	 * 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);
-
-	/**
-	 * Stores the local identity registered with
-	 * {@link #registerLocalAuthor(LocalAuthor)}, if any.
-	 */
-	void storeLocalAuthor() throws DbException;
+	void registerIdentity(Identity i);
 
 	/**
 	 * Returns the cached local identity or loads it from the database.
@@ -33,7 +32,18 @@ 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.
+	 *
+	 * @return A two-element array containing the public key in the first
+	 * element and the private key in the second
+	 */
+	byte[][] getHandshakeKeys(Transaction txn) throws DbException;
 }

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

@@ -2,11 +2,8 @@ package org.briarproject.bramble.api.identity;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
-import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 
-import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
-
 /**
  * A pseudonym for the local user.
  */
@@ -15,31 +12,11 @@ import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_K
 public class LocalAuthor extends Author {
 
 	private final byte[] privateKey;
-	@Nullable
-	private final byte[] handshakePublicKey, handshakePrivateKey;
-	private final long created;
 
 	public LocalAuthor(AuthorId id, int formatVersion, String name,
-			byte[] publicKey, byte[] privateKey, long created) {
+			byte[] publicKey, byte[] privateKey) {
 		super(id, formatVersion, name, publicKey);
 		this.privateKey = privateKey;
-		this.created = created;
-		handshakePublicKey = null;
-		handshakePrivateKey = null;
-	}
-
-	public LocalAuthor(AuthorId id, int formatVersion, String name,
-			byte[] publicKey, byte[] privateKey, byte[] handshakePublicKey,
-			byte[] handshakePrivateKey, long created) {
-		super(id, formatVersion, name, publicKey);
-		if (handshakePublicKey.length == 0 ||
-				handshakePublicKey.length > MAX_PUBLIC_KEY_LENGTH) {
-			throw new IllegalArgumentException();
-		}
-		this.privateKey = privateKey;
-		this.handshakePublicKey = handshakePublicKey;
-		this.handshakePrivateKey = handshakePrivateKey;
-		this.created = created;
 	}
 
 	/**
@@ -48,28 +25,4 @@ public class LocalAuthor extends Author {
 	public byte[] 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
- * and stopping {@link Service Services}, shutting down
- * {@link ExecutorService ExecutorServices}, and opening and closing the
- * {@link DatabaseComponent}.
+ * Manages the lifecycle of the app: opening and closing the
+ * {@link DatabaseComponent} starting and stopping {@link Service Services},
+ * and shutting down {@link ExecutorService ExecutorServices}.
  */
 @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
-	 * returning.
+	 * {@link Service Services} to start before 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/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/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/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

@@ -8,6 +8,7 @@ import org.briarproject.bramble.api.contact.PendingContactId;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
+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;
@@ -30,6 +31,7 @@ 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.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;
@@ -99,25 +101,26 @@ public class TestUtils {
 		return new SecretKey(getRandomBytes(SecretKey.LENGTH));
 	}
 
-	public static LocalAuthor getLocalAuthor() {
-		return getLocalAuthor(1 + random.nextInt(MAX_AUTHOR_NAME_LENGTH));
-	}
-
-	public static LocalAuthor getLocalAuthor(int nameLength) {
-		AuthorId id = new AuthorId(getRandomId());
-		String name = getRandomString(nameLength);
-		byte[] publicKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
-		byte[] privateKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
-		return new LocalAuthor(id, FORMAT_VERSION, name, publicKey, privateKey,
+	public static Identity getIdentity() {
+		LocalAuthor localAuthor = getLocalAuthor();
+		byte[] handshakePub = getRandomBytes(MAX_AGREEMENT_PUBLIC_KEY_BYTES);
+		byte[] handshakePriv = getRandomBytes(MAX_AGREEMENT_PUBLIC_KEY_BYTES);
+		return new Identity(localAuthor, handshakePub, handshakePriv,
 				timestamp);
 	}
 
-	public static Author getAuthor() {
-		return getAuthor(1 + random.nextInt(MAX_AUTHOR_NAME_LENGTH));
+	public static LocalAuthor getLocalAuthor() {
+		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);
+		byte[] privateKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
+		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);
 		return new Author(id, FORMAT_VERSION, name, publicKey);

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

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.PendingContactState.WAITING_FOR_CONNECTION;
+import static org.briarproject.bramble.api.contact.HandshakeLinkConstants.BASE32_LINK_BYTES;
 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);
-	private static final Pattern LINK_REGEX =
-			Pattern.compile("(briar://)?([a-z2-7]{" + LINK_LENGTH + "})");
+			"briar://" + getRandomBase32String(BASE32_LINK_BYTES);
 
 	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<>();
 	}
 
@@ -97,45 +95,28 @@ class ContactManagerImpl implements ContactManager {
 	}
 
 	@Override
-	public String getRemoteContactLink() {
+	public String getHandshakeLink() {
 		// TODO replace with real implementation
 		return REMOTE_CONTACT_LINK;
 	}
 
-	@SuppressWarnings("SameParameterValue")
-	private static String getRandomBase32String(int length) {
-		Random random = new Random();
-		char[] c = new char[length];
-		for (int i = 0; i < length; i++) {
-			int character = random.nextInt(32);
-			if (character < 26) c[i] = (char) ('a' + character);
-			else c[i] = (char) ('2' + (character - 26));
-		}
-		return new String(c);
+	@Override
+	public PendingContact addPendingContact(String link, String alias)
+			throws DbException, FormatException {
+		PendingContact p =
+				pendingContactFactory.createPendingContact(link, alias);
+		db.transaction(false, txn -> db.addPendingContact(txn, p));
+		return p;
 	}
 
 	@Override
-	public boolean isValidRemoteContactLink(String link) {
-		return LINK_REGEX.matcher(link).matches();
+	public Collection<PendingContact> getPendingContacts() throws DbException {
+		return db.transactionWithResult(true, db::getPendingContacts);
 	}
 
 	@Override
-	public PendingContact addRemoteContactRequest(String link, String alias) {
-		// TODO replace with real implementation
-		PendingContactId id = new PendingContactId(link.getBytes());
-		return new PendingContact(id, new byte[MAX_PUBLIC_KEY_LENGTH], alias,
-				WAITING_FOR_CONNECTION, System.currentTimeMillis());
-	}
-
-	@Override
-	public Collection<PendingContact> getPendingContacts() {
-		// TODO replace with real implementation
-		return emptyList();
-	}
-
-	@Override
-	public void removePendingContact(PendingContact pendingContact) {
-		// TODO replace with real implementation
+	public void removePendingContact(PendingContactId p) throws DbException {
+		db.transaction(false, txn -> db.removePendingContact(txn, p));
 	}
 
 	@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.getEncoded(), 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/db/Database.java

@@ -15,7 +15,7 @@ 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;
@@ -120,9 +120,9 @@ interface Database<T> {
 			HandshakeKeys k) throws DbException;
 
 	/**
-	 * Stores a local pseudonym.
+	 * Stores an identity.
 	 */
-	void addLocalAuthor(T txn, LocalAuthor a) throws DbException;
+	void addIdentity(T txn, Identity i) throws DbException;
 
 	/**
 	 * Stores a message.
@@ -187,11 +187,12 @@ 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.
@@ -323,18 +324,18 @@ interface Database<T> {
 			throws DbException;
 
 	/**
-	 * Returns the local pseudonym with the given ID.
+	 * Returns the identity for local pseudonym with the given ID.
 	 * <p/>
 	 * Read-only.
 	 */
-	LocalAuthor getLocalAuthor(T txn, AuthorId a) throws DbException;
+	Identity getIdentity(T txn, AuthorId a) throws DbException;
 
 	/**
-	 * Returns all local pseudonyms.
+	 * Returns the identities for all local pseudonyms.
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<LocalAuthor> getLocalAuthors(T txn) throws DbException;
+	Collection<Identity> getIdentities(T txn) throws DbException;
 
 	/**
 	 * Returns the message with the given ID.
@@ -629,9 +630,9 @@ interface Database<T> {
 			throws DbException;
 
 	/**
-	 * Removes a local pseudonym (and all associated state) from the database.
+	 * Removes an identity (and all associated state) from the database.
 	 */
-	void removeLocalAuthor(T txn, AuthorId a) throws DbException;
+	void removeIdentity(T txn, AuthorId a) throws DbException;
 
 	/**
 	 * Removes a message (and all associated state) from the database.
@@ -685,6 +686,12 @@ 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, byte[] publicKey,
+			byte[] privateKey) throws DbException;
+
 	/**
 	 * Marks the given message as shared.
 	 */

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

@@ -20,7 +20,7 @@ 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 +32,9 @@ 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.event.LocalAuthorAddedEvent;
-import org.briarproject.bramble.api.identity.event.LocalAuthorRemovedEvent;
+import org.briarproject.bramble.api.identity.Identity;
+import org.briarproject.bramble.api.identity.event.IdentityAddedEvent;
+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;
@@ -237,9 +237,9 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
-		if (!db.containsLocalAuthor(txn, local))
-			throw new NoSuchLocalAuthorException();
-		if (db.containsLocalAuthor(txn, remote.getId()))
+		if (!db.containsIdentity(txn, local))
+			throw new NoSuchIdentityException();
+		if (db.containsIdentity(txn, remote.getId()))
 			throw new ContactExistsException();
 		if (db.containsContact(txn, remote.getId(), local))
 			throw new ContactExistsException();
@@ -283,13 +283,13 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public void addLocalAuthor(Transaction transaction, LocalAuthor a)
+	public void addIdentity(Transaction transaction, Identity i)
 			throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
-		if (!db.containsLocalAuthor(txn, a.getId())) {
-			db.addLocalAuthor(txn, a);
-			transaction.attach(new LocalAuthorAddedEvent(a.getId()));
+		if (!db.containsIdentity(txn, i.getId())) {
+			db.addIdentity(txn, i);
+			transaction.attach(new IdentityAddedEvent(i.getId()));
 		}
 	}
 
@@ -345,8 +345,8 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	public boolean containsContact(Transaction transaction, AuthorId remote,
 			AuthorId local) throws DbException {
 		T txn = unbox(transaction);
-		if (!db.containsLocalAuthor(txn, local))
-			throw new NoSuchLocalAuthorException();
+		if (!db.containsIdentity(txn, local))
+			throw new NoSuchIdentityException();
 		return db.containsContact(txn, remote, local);
 	}
 
@@ -358,10 +358,10 @@ 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
@@ -505,8 +505,8 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	public Collection<ContactId> getContacts(Transaction transaction,
 			AuthorId a) throws DbException {
 		T txn = unbox(transaction);
-		if (!db.containsLocalAuthor(txn, a))
-			throw new NoSuchLocalAuthorException();
+		if (!db.containsIdentity(txn, a))
+			throw new NoSuchIdentityException();
 		return db.getContacts(txn, a);
 	}
 
@@ -554,19 +554,19 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public LocalAuthor getLocalAuthor(Transaction transaction, AuthorId a)
+	public Identity getIdentity(Transaction transaction, AuthorId a)
 			throws DbException {
 		T txn = unbox(transaction);
-		if (!db.containsLocalAuthor(txn, a))
-			throw new NoSuchLocalAuthorException();
-		return db.getLocalAuthor(txn, a);
+		if (!db.containsIdentity(txn, a))
+			throw new NoSuchIdentityException();
+		return db.getIdentity(txn, a);
 	}
 
 	@Override
-	public Collection<LocalAuthor> getLocalAuthors(Transaction transaction)
+	public Collection<Identity> getIdentities(Transaction transaction)
 			throws DbException {
 		T txn = unbox(transaction);
-		return db.getLocalAuthors(txn);
+		return db.getIdentities(txn);
 	}
 
 	@Override
@@ -905,14 +905,14 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public void removeLocalAuthor(Transaction transaction, AuthorId a)
+	public void removeIdentity(Transaction transaction, AuthorId a)
 			throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
-		if (!db.containsLocalAuthor(txn, a))
-			throw new NoSuchLocalAuthorException();
-		db.removeLocalAuthor(txn, a);
-		transaction.attach(new LocalAuthorRemovedEvent(a));
+		if (!db.containsIdentity(txn, a))
+			throw new NoSuchIdentityException();
+		db.removeIdentity(txn, a);
+		transaction.attach(new IdentityRemovedEvent(a));
 	}
 
 	@Override
@@ -1035,6 +1035,16 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		}
 	}
 
+	@Override
+	public void setHandshakeKeyPair(Transaction transaction, AuthorId local,
+			byte[] publicKey, byte[] privateKey) throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsIdentity(txn, local))
+			throw new NoSuchIdentityException();
+		db.setHandshakeKeyPair(txn, local, publicKey, privateKey);
+	}
+
 	@Override
 	public void setReorderingWindow(Transaction transaction,
 			TransportKeySetId k, TransportId t, long timePeriod, long base,

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

@@ -15,6 +15,7 @@ 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;
@@ -874,8 +875,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public void addLocalAuthor(Connection txn, LocalAuthor a)
-			throws DbException {
+	public void addIdentity(Connection txn, Identity i) throws DbException {
 		PreparedStatement ps = null;
 		try {
 			String sql = "INSERT INTO localAuthors"
@@ -883,16 +883,17 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " handshakePublicKey, handshakePrivateKey, created)"
 					+ " VALUES (?, ?, ?, ?, ?, ?, ?, ?)";
 			ps = txn.prepareStatement(sql);
-			ps.setBytes(1, a.getId().getBytes());
-			ps.setInt(2, a.getFormatVersion());
-			ps.setString(3, a.getName());
-			ps.setBytes(4, a.getPublicKey());
-			ps.setBytes(5, a.getPrivateKey());
-			if (a.getHandshakePublicKey() == null) ps.setNull(6, BINARY);
-			else ps.setBytes(6, a.getHandshakePublicKey());
-			if (a.getHandshakePrivateKey() == null) ps.setNull(7, BINARY);
-			else ps.setBytes(7, a.getHandshakePrivateKey());
-			ps.setLong(8, a.getTimeCreated());
+			LocalAuthor local = i.getLocalAuthor();
+			ps.setBytes(1, local.getId().getBytes());
+			ps.setInt(2, local.getFormatVersion());
+			ps.setString(3, local.getName());
+			ps.setBytes(4, local.getPublicKey());
+			ps.setBytes(5, local.getPrivateKey());
+			if (i.getHandshakePublicKey() == null) ps.setNull(6, BINARY);
+			else ps.setBytes(6, i.getHandshakePublicKey());
+			if (i.getHandshakePrivateKey() == null) ps.setNull(7, BINARY);
+			else ps.setBytes(7, i.getHandshakePrivateKey());
+			ps.setLong(8, i.getTimeCreated());
 			int affected = ps.executeUpdate();
 			if (affected != 1) throw new DbStateException();
 			ps.close();
@@ -1248,7 +1249,7 @@ 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;
@@ -1660,41 +1661,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
-	@Override
-	public LocalAuthor getLocalAuthor(Connection txn, AuthorId a)
-			throws DbException {
-		PreparedStatement ps = null;
-		ResultSet rs = null;
-		try {
-			String sql = "SELECT formatVersion, name, publicKey, privateKey,"
-					+ " handshakePublicKey, handshakePrivateKey, created"
-					+ " FROM localAuthors"
-					+ " WHERE authorId = ?";
-			ps = txn.prepareStatement(sql);
-			ps.setBytes(1, a.getBytes());
-			rs = ps.executeQuery();
-			if (!rs.next()) throw new DbStateException();
-			int formatVersion = rs.getInt(1);
-			String name = rs.getString(2);
-			byte[] publicKey = rs.getBytes(3);
-			byte[] privateKey = rs.getBytes(4);
-			byte[] handshakePublicKey = rs.getBytes(5);
-			byte[] handshakePrivateKey = 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;
-		} catch (SQLException e) {
-			tryToClose(rs, LOG, WARNING);
-			tryToClose(ps, LOG, WARNING);
-			throw new DbException(e);
-		}
-	}
-
 	@Override
 	public Collection<HandshakeKeySet> getHandshakeKeys(Connection txn,
 			TransportId t) throws DbException {
@@ -1776,30 +1742,69 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public Collection<LocalAuthor> getLocalAuthors(Connection txn)
+	public Identity getIdentity(Connection txn, AuthorId a) throws DbException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT formatVersion, name, publicKey, privateKey,"
+					+ " handshakePublicKey, handshakePrivateKey, created"
+					+ " FROM localAuthors"
+					+ " WHERE authorId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, a.getBytes());
+			rs = ps.executeQuery();
+			if (!rs.next()) throw new DbStateException();
+			int formatVersion = rs.getInt(1);
+			String name = rs.getString(2);
+			byte[] publicKey = rs.getBytes(3);
+			byte[] privateKey = rs.getBytes(4);
+			byte[] handshakePublicKey = rs.getBytes(5);
+			byte[] handshakePrivateKey = rs.getBytes(6);
+			long created = rs.getLong(7);
+			if (rs.next()) throw new DbStateException();
+			rs.close();
+			ps.close();
+			LocalAuthor local = new LocalAuthor(a, formatVersion, name,
+					publicKey, privateKey);
+			return new Identity(local, handshakePublicKey, handshakePrivateKey,
+					created);
+		} catch (SQLException e) {
+			tryToClose(rs, LOG, WARNING);
+			tryToClose(ps, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+
+	@Override
+	public Collection<Identity> getIdentities(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);
 				byte[] privateKey = rs.getBytes(5);
-				long created = rs.getLong(6);
-				authors.add(new LocalAuthor(authorId, formatVersion, name,
-						publicKey, privateKey, created));
+				byte[] handshakePublicKey = rs.getBytes(6);
+				byte[] handshakePrivateKey = rs.getBytes(7);
+				long created = rs.getLong(8);
+				LocalAuthor local = new LocalAuthor(authorId, formatVersion,
+						name, publicKey, privateKey);
+				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);
@@ -2958,8 +2963,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public void removeLocalAuthor(Connection txn, AuthorId a)
-			throws DbException {
+	public void removeIdentity(Connection txn, AuthorId a) throws DbException {
 		PreparedStatement ps = null;
 		try {
 			String sql = "DELETE FROM localAuthors WHERE authorId = ?";
@@ -3176,6 +3180,27 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	@Override
+	public void setHandshakeKeyPair(Connection txn, AuthorId local,
+			byte[] publicKey, byte[] privateKey) throws DbException {
+		PreparedStatement ps = null;
+		try {
+			String sql = "UPDATE localAuthors"
+					+ " SET handshakePublicKey = ?, handshakePrivateKey = ?"
+					+ " WHERE authorId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, publicKey);
+			ps.setBytes(2, privateKey);
+			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 {

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

@@ -1,12 +1,12 @@
 package org.briarproject.bramble.identity;
 
 import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.KeyPair;
 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;
 
@@ -22,12 +22,10 @@ import static org.briarproject.bramble.util.ByteUtils.INT_32_BYTES;
 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
@@ -43,17 +41,12 @@ class AuthorFactoryImpl implements AuthorFactory {
 	}
 
 	@Override
-	public LocalAuthor createLocalAuthor(String name, byte[] publicKey,
-			byte[] privateKey) {
-		return createLocalAuthor(FORMAT_VERSION, name, publicKey, privateKey);
-	}
-
-	@Override
-	public LocalAuthor createLocalAuthor(int formatVersion, String name,
-			byte[] publicKey, byte[] privateKey) {
-		AuthorId id = getId(formatVersion, name, publicKey);
-		return new LocalAuthor(id, formatVersion, name, publicKey, privateKey,
-				clock.currentTimeMillis());
+	public LocalAuthor createLocalAuthor(String name) {
+		KeyPair signatureKeyPair = crypto.generateSignatureKeyPair();
+		byte[] publicKey = signatureKeyPair.getPublic().getEncoded();
+		byte[] privateKey = signatureKeyPair.getPrivate().getEncoded();
+		AuthorId id = getId(FORMAT_VERSION, name, publicKey);
+		return new LocalAuthor(id, FORMAT_VERSION, name, publicKey, privateKey);
 	}
 
 	private AuthorId getId(int formatVersion, String name, byte[] publicKey) {

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

@@ -6,97 +6,164 @@ 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();
-		byte[] publicKey = keyPair.getPublic().getEncoded();
-		byte[] privateKey = keyPair.getPrivate().getEncoded();
-		LocalAuthor localAuthor = authorFactory.createLocalAuthor(name,
-				publicKey, privateKey);
-		logDuration(LOG, "Creating local author", start);
-		return localAuthor;
+		LocalAuthor localAuthor = authorFactory.createLocalAuthor(name);
+		KeyPair handshakeKeyPair = crypto.generateAgreementKeyPair();
+		byte[] handshakePub = handshakeKeyPair.getPublic().getEncoded();
+		byte[] handshakePriv = handshakeKeyPair.getPrivate().getEncoded();
+		logDuration(LOG, "Creating identity", start);
+		return new Identity(localAuthor, handshakePub, handshakePriv,
+				clock.currentTimeMillis());
 	}
 
 	@Override
-	public void registerLocalAuthor(LocalAuthor a) {
-		cachedAuthor = a;
-		LOG.info("Local author registered");
+	public void registerIdentity(Identity i) {
+		if (!i.hasHandshakeKeyPair()) throw new IllegalArgumentException();
+		cachedIdentity = i;
+		shouldStoreIdentity = true;
+		LOG.info("Identity registered");
 	}
 
 	@Override
-	public void storeLocalAuthor() throws DbException {
-		LocalAuthor cached = cachedAuthor;
-		if (cached == null) {
-			LOG.info("No local author to store");
-			return;
+	public void onDatabaseOpened(Transaction txn) throws DbException {
+		Identity cached = getCachedIdentity(txn);
+		if (shouldStoreIdentity) {
+			// The identity was registered at startup - store it
+			db.addIdentity(txn, cached);
+			LOG.info("Identity stored");
+		} else if (shouldStoreKeys) {
+			// Handshake keys were generated when loading the identity -
+			// store them
+			byte[] handshakePub =
+					requireNonNull(cached.getHandshakePublicKey());
+			byte[] 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) {
-			cachedAuthor =
-					db.transactionWithResult(true, this::loadLocalAuthor);
-			LOG.info("Local author loaded");
-		}
-		LocalAuthor cached = cachedAuthor;
-		if (cached == null) throw new AssertionError();
-		return cached;
+		Identity cached = cachedIdentity;
+		if (cached == null)
+			cached = db.transactionWithResult(true, this::getCachedIdentity);
+		return cached.getLocalAuthor();
 	}
 
-
 	@Override
 	public LocalAuthor getLocalAuthor(Transaction txn) throws DbException {
-		if (cachedAuthor == null) {
-			cachedAuthor = loadLocalAuthor(txn);
-			LOG.info("Local author loaded");
-		}
-		LocalAuthor cached = cachedAuthor;
-		if (cached == null) throw new AssertionError();
+		return getCachedIdentity(txn).getLocalAuthor();
+	}
+
+	@Override
+	public byte[][] getHandshakeKeys(Transaction txn) throws DbException {
+		Identity cached = getCachedIdentity(txn);
+		return new byte[][] {
+				cached.getHandshakePublicKey(),
+				cached.getHandshakePrivateKey()
+		};
+	}
+
+	/**
+	 * 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();
+		byte[] handshakePub = handshakeKeyPair.getPublic().getEncoded();
+		byte[] handshakePriv = handshakeKeyPair.getPrivate().getEncoded();
+		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,
-			IdentityManager identityManager) {
+	LifecycleManagerImpl(DatabaseComponent db, EventBus eventBus) {
 		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) {
-		if (LOG.isLoggable(INFO))
-			LOG.info("Registering client " + c.getClass().getSimpleName());
-		clients.add(c);
+	public void registerOpenDatabaseHook(OpenDatabaseHook hook) {
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Registering open database hook "
+					+ 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/PluginManagerImpl.java

@@ -8,7 +8,6 @@ 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.plugin.ConnectionManager;
-import org.briarproject.bramble.api.plugin.ConnectionRegistry;
 import org.briarproject.bramble.api.plugin.Plugin;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.PluginConfig;
@@ -30,10 +29,7 @@ import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.properties.TransportPropertyManager;
 import org.briarproject.bramble.api.settings.Settings;
 import org.briarproject.bramble.api.settings.SettingsManager;
-import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.bramble.api.system.Scheduler;
 
-import java.security.SecureRandom;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
@@ -42,7 +38,6 @@ import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Executor;
-import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
 
@@ -64,15 +59,11 @@ class PluginManagerImpl implements PluginManager, Service {
 			Logger.getLogger(PluginManagerImpl.class.getName());
 
 	private final Executor ioExecutor;
-	private final ScheduledExecutorService scheduler;
 	private final EventBus eventBus;
 	private final PluginConfig pluginConfig;
 	private final ConnectionManager connectionManager;
-	private final ConnectionRegistry connectionRegistry;
 	private final SettingsManager settingsManager;
 	private final TransportPropertyManager transportPropertyManager;
-	private final SecureRandom random;
-	private final Clock clock;
 	private final Map<TransportId, Plugin> plugins;
 	private final List<SimplexPlugin> simplexPlugins;
 	private final List<DuplexPlugin> duplexPlugins;
@@ -80,41 +71,25 @@ class PluginManagerImpl implements PluginManager, Service {
 	private final AtomicBoolean used = new AtomicBoolean(false);
 
 	@Inject
-	PluginManagerImpl(@IoExecutor Executor ioExecutor,
-			@Scheduler ScheduledExecutorService scheduler, EventBus eventBus,
+	PluginManagerImpl(@IoExecutor Executor ioExecutor, EventBus eventBus,
 			PluginConfig pluginConfig, ConnectionManager connectionManager,
-			ConnectionRegistry connectionRegistry,
 			SettingsManager settingsManager,
-			TransportPropertyManager transportPropertyManager,
-			SecureRandom random, Clock clock) {
+			TransportPropertyManager transportPropertyManager) {
 		this.ioExecutor = ioExecutor;
-		this.scheduler = scheduler;
 		this.eventBus = eventBus;
 		this.pluginConfig = pluginConfig;
 		this.connectionManager = connectionManager;
-		this.connectionRegistry = connectionRegistry;
 		this.settingsManager = settingsManager;
 		this.transportPropertyManager = transportPropertyManager;
-		this.random = random;
-		this.clock = clock;
 		plugins = new ConcurrentHashMap<>();
 		simplexPlugins = new CopyOnWriteArrayList<>();
 		duplexPlugins = new CopyOnWriteArrayList<>();
 		startLatches = new ConcurrentHashMap<>();
-
 	}
 
 	@Override
 	public void startService() {
 		if (used.getAndSet(true)) throw new IllegalStateException();
-		// Instantiate the poller
-		if (pluginConfig.shouldPoll()) {
-			LOG.info("Starting poller");
-			Poller poller = new Poller(ioExecutor, scheduler, connectionManager,
-					connectionRegistry, this, transportPropertyManager, random,
-					clock);
-			eventBus.addListener(poller);
-		}
 		// Instantiate the simplex plugins and start them asynchronously
 		LOG.info("Starting simplex plugins");
 		for (SimplexPluginFactory f : pluginConfig.getSimplexFactories()) {

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

@@ -1,9 +1,11 @@
 package org.briarproject.bramble.plugin;
 
+import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.plugin.BackoffFactory;
 import org.briarproject.bramble.api.plugin.ConnectionManager;
 import org.briarproject.bramble.api.plugin.ConnectionRegistry;
+import org.briarproject.bramble.api.plugin.PluginConfig;
 import org.briarproject.bramble.api.plugin.PluginManager;
 
 import javax.inject.Inject;
@@ -18,6 +20,8 @@ public class PluginModule {
 	public static class EagerSingletons {
 		@Inject
 		PluginManager pluginManager;
+		@Inject
+		Poller poller;
 	}
 
 	@Provides
@@ -46,4 +50,12 @@ public class PluginModule {
 		lifecycleManager.registerService(pluginManager);
 		return pluginManager;
 	}
+
+	@Provides
+	@Singleton
+	Poller providePoller(PluginConfig config, EventBus eventBus,
+			PollerImpl poller) {
+		if (config.shouldPoll()) eventBus.addListener(poller);
+		return poller;
+	}
 }

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

@@ -1,259 +1,7 @@
 package org.briarproject.bramble.plugin;
 
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.contact.event.ContactAddedEvent;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.event.EventListener;
-import org.briarproject.bramble.api.lifecycle.IoExecutor;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.ConnectionManager;
-import org.briarproject.bramble.api.plugin.ConnectionRegistry;
-import org.briarproject.bramble.api.plugin.Plugin;
-import org.briarproject.bramble.api.plugin.PluginManager;
-import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
-import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
-import org.briarproject.bramble.api.plugin.event.TransportDisabledEvent;
-import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
-import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
-import org.briarproject.bramble.api.properties.TransportProperties;
-import org.briarproject.bramble.api.properties.TransportPropertyManager;
-import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.bramble.api.system.Scheduler;
-
-import java.security.SecureRandom;
-import java.util.Collection;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.concurrent.Executor;
-import java.util.concurrent.Future;
-import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.locks.Lock;
-import java.util.concurrent.locks.ReentrantLock;
-import java.util.logging.Logger;
-
-import javax.annotation.concurrent.ThreadSafe;
-
-import static java.util.concurrent.TimeUnit.MILLISECONDS;
-import static java.util.logging.Level.INFO;
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.LogUtils.logException;
-
-@ThreadSafe
-@NotNullByDefault
-class Poller implements EventListener {
-
-	private static final Logger LOG = Logger.getLogger(Poller.class.getName());
-
-	private final Executor ioExecutor;
-	private final ScheduledExecutorService scheduler;
-	private final ConnectionManager connectionManager;
-	private final ConnectionRegistry connectionRegistry;
-	private final PluginManager pluginManager;
-	private final TransportPropertyManager transportPropertyManager;
-	private final SecureRandom random;
-	private final Clock clock;
-	private final Lock lock;
-	private final Map<TransportId, ScheduledPollTask> tasks; // Locking: lock
-
-	Poller(@IoExecutor Executor ioExecutor,
-			@Scheduler ScheduledExecutorService scheduler,
-			ConnectionManager connectionManager,
-			ConnectionRegistry connectionRegistry, PluginManager pluginManager,
-			TransportPropertyManager transportPropertyManager,
-			SecureRandom random, Clock clock) {
-		this.ioExecutor = ioExecutor;
-		this.scheduler = scheduler;
-		this.connectionManager = connectionManager;
-		this.connectionRegistry = connectionRegistry;
-		this.pluginManager = pluginManager;
-		this.transportPropertyManager = transportPropertyManager;
-		this.random = random;
-		this.clock = clock;
-		lock = new ReentrantLock();
-		tasks = new HashMap<>();
-	}
-
-	@Override
-	public void eventOccurred(Event e) {
-		if (e instanceof ContactAddedEvent) {
-			ContactAddedEvent c = (ContactAddedEvent) e;
-			// Connect to the newly activated contact
-			connectToContact(c.getContactId());
-		} else if (e instanceof ConnectionClosedEvent) {
-			ConnectionClosedEvent c = (ConnectionClosedEvent) e;
-			// Reschedule polling, the polling interval may have decreased
-			reschedule(c.getTransportId());
-			if (!c.isIncoming()) {
-				// Connect to the disconnected contact
-				connectToContact(c.getContactId(), c.getTransportId());
-			}
-		} else if (e instanceof ConnectionOpenedEvent) {
-			ConnectionOpenedEvent c = (ConnectionOpenedEvent) e;
-			// Reschedule polling, the polling interval may have decreased
-			reschedule(c.getTransportId());
-		} else if (e instanceof TransportEnabledEvent) {
-			TransportEnabledEvent t = (TransportEnabledEvent) e;
-			// Poll the newly enabled transport
-			pollNow(t.getTransportId());
-		} else if (e instanceof TransportDisabledEvent) {
-			TransportDisabledEvent t = (TransportDisabledEvent) e;
-			// Cancel polling for the disabled transport
-			cancel(t.getTransportId());
-		}
-	}
-
-	private void connectToContact(ContactId c) {
-		for (SimplexPlugin s : pluginManager.getSimplexPlugins())
-			if (s.shouldPoll()) connectToContact(c, s);
-		for (DuplexPlugin d : pluginManager.getDuplexPlugins())
-			if (d.shouldPoll()) connectToContact(c, d);
-	}
-
-	private void connectToContact(ContactId c, TransportId t) {
-		Plugin p = pluginManager.getPlugin(t);
-		if (p instanceof SimplexPlugin && p.shouldPoll())
-			connectToContact(c, (SimplexPlugin) p);
-		else if (p instanceof DuplexPlugin && p.shouldPoll())
-			connectToContact(c, (DuplexPlugin) p);
-	}
-
-	private void connectToContact(ContactId c, SimplexPlugin p) {
-		ioExecutor.execute(() -> {
-			TransportId t = p.getId();
-			if (connectionRegistry.isConnected(c, t)) return;
-			try {
-				TransportProperties props =
-						transportPropertyManager.getRemoteProperties(c, t);
-				TransportConnectionWriter w = p.createWriter(props);
-				if (w != null)
-					connectionManager.manageOutgoingConnection(c, t, w);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
-	}
-
-	private void connectToContact(ContactId c, DuplexPlugin p) {
-		ioExecutor.execute(() -> {
-			TransportId t = p.getId();
-			if (connectionRegistry.isConnected(c, t)) return;
-			try {
-				TransportProperties props =
-						transportPropertyManager.getRemoteProperties(c, t);
-				DuplexTransportConnection d = p.createConnection(props);
-				if (d != null)
-					connectionManager.manageOutgoingConnection(c, t, d);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
-	}
-
-	private void reschedule(TransportId t) {
-		Plugin p = pluginManager.getPlugin(t);
-		if (p != null && p.shouldPoll())
-			schedule(p, p.getPollingInterval(), false);
-	}
-
-	private void pollNow(TransportId t) {
-		Plugin p = pluginManager.getPlugin(t);
-		// Randomise next polling interval
-		if (p != null && p.shouldPoll()) schedule(p, 0, true);
-	}
-
-	private void schedule(Plugin p, int delay, boolean randomiseNext) {
-		// Replace any later scheduled task for this plugin
-		long due = clock.currentTimeMillis() + delay;
-		TransportId t = p.getId();
-		lock.lock();
-		try {
-			ScheduledPollTask scheduled = tasks.get(t);
-			if (scheduled == null || due < scheduled.task.due) {
-				// If a later task exists, cancel it. If it's already started
-				// it will abort safely when it finds it's been replaced
-				if (scheduled != null) scheduled.future.cancel(false);
-				PollTask task = new PollTask(p, due, randomiseNext);
-				Future future = scheduler.schedule(
-						() -> ioExecutor.execute(task), delay, MILLISECONDS);
-				tasks.put(t, new ScheduledPollTask(task, future));
-			}
-		} finally {
-			lock.unlock();
-		}
-	}
-
-	private void cancel(TransportId t) {
-		lock.lock();
-		try {
-			ScheduledPollTask scheduled = tasks.remove(t);
-			if (scheduled != null) scheduled.future.cancel(false);
-		} finally {
-			lock.unlock();
-		}
-	}
-
-	@IoExecutor
-	private void poll(Plugin p) {
-		TransportId t = p.getId();
-		if (LOG.isLoggable(INFO)) LOG.info("Polling plugin " + t);
-		try {
-			Map<ContactId, TransportProperties> remote =
-					transportPropertyManager.getRemoteProperties(t);
-			Collection<ContactId> connected =
-					connectionRegistry.getConnectedContacts(t);
-			remote = new HashMap<>(remote);
-			remote.keySet().removeAll(connected);
-			if (!remote.isEmpty()) p.poll(remote);
-		} catch (DbException e) {
-			logException(LOG, WARNING, e);
-		}
-	}
-
-	private class ScheduledPollTask {
-
-		private final PollTask task;
-		private final Future future;
-
-		private ScheduledPollTask(PollTask task, Future future) {
-			this.task = task;
-			this.future = future;
-		}
-	}
-
-	private class PollTask implements Runnable {
-
-		private final Plugin plugin;
-		private final long due;
-		private final boolean randomiseNext;
-
-		private PollTask(Plugin plugin, long due, boolean randomiseNext) {
-			this.plugin = plugin;
-			this.due = due;
-			this.randomiseNext = randomiseNext;
-		}
-
-		@Override
-		@IoExecutor
-		public void run() {
-			lock.lock();
-			try {
-				TransportId t = plugin.getId();
-				ScheduledPollTask scheduled = tasks.get(t);
-				if (scheduled != null && scheduled.task != this)
-					return; // Replaced by another task
-				tasks.remove(t);
-			} finally {
-				lock.unlock();
-			}
-			int delay = plugin.getPollingInterval();
-			if (randomiseNext) delay = (int) (delay * random.nextDouble());
-			schedule(plugin, delay, false);
-			poll(plugin);
-		}
-	}
+/**
+ * Empty interface used for injecting the poller.
+ */
+interface Poller {
 }

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

@@ -0,0 +1,264 @@
+package org.briarproject.bramble.plugin;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.event.ContactAddedEvent;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventListener;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.ConnectionManager;
+import org.briarproject.bramble.api.plugin.ConnectionRegistry;
+import org.briarproject.bramble.api.plugin.Plugin;
+import org.briarproject.bramble.api.plugin.PluginManager;
+import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
+import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
+import org.briarproject.bramble.api.plugin.event.TransportDisabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
+import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
+import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.bramble.api.properties.TransportPropertyManager;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.system.Scheduler;
+
+import java.security.SecureRandom;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Future;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.logging.Logger;
+
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+import javax.inject.Inject;
+
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+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.util.LogUtils.logException;
+
+@ThreadSafe
+@NotNullByDefault
+class PollerImpl implements Poller, EventListener {
+
+	private static final Logger LOG = getLogger(PollerImpl.class.getName());
+
+	private final Executor ioExecutor;
+	private final ScheduledExecutorService scheduler;
+	private final ConnectionManager connectionManager;
+	private final ConnectionRegistry connectionRegistry;
+	private final PluginManager pluginManager;
+	private final TransportPropertyManager transportPropertyManager;
+	private final SecureRandom random;
+	private final Clock clock;
+	private final Lock lock;
+	@GuardedBy("lock")
+	private final Map<TransportId, ScheduledPollTask> tasks;
+
+	@Inject
+	PollerImpl(@IoExecutor Executor ioExecutor,
+			@Scheduler ScheduledExecutorService scheduler,
+			ConnectionManager connectionManager,
+			ConnectionRegistry connectionRegistry, PluginManager pluginManager,
+			TransportPropertyManager transportPropertyManager,
+			SecureRandom random, Clock clock) {
+		this.ioExecutor = ioExecutor;
+		this.scheduler = scheduler;
+		this.connectionManager = connectionManager;
+		this.connectionRegistry = connectionRegistry;
+		this.pluginManager = pluginManager;
+		this.transportPropertyManager = transportPropertyManager;
+		this.random = random;
+		this.clock = clock;
+		lock = new ReentrantLock();
+		tasks = new HashMap<>();
+	}
+
+	@Override
+	public void eventOccurred(Event e) {
+		if (e instanceof ContactAddedEvent) {
+			ContactAddedEvent c = (ContactAddedEvent) e;
+			// Connect to the newly added contact
+			connectToContact(c.getContactId());
+		} else if (e instanceof ConnectionClosedEvent) {
+			ConnectionClosedEvent c = (ConnectionClosedEvent) e;
+			// Reschedule polling, the polling interval may have decreased
+			reschedule(c.getTransportId());
+			if (!c.isIncoming()) {
+				// Connect to the disconnected contact
+				connectToContact(c.getContactId(), c.getTransportId());
+			}
+		} else if (e instanceof ConnectionOpenedEvent) {
+			ConnectionOpenedEvent c = (ConnectionOpenedEvent) e;
+			// Reschedule polling, the polling interval may have decreased
+			reschedule(c.getTransportId());
+		} else if (e instanceof TransportEnabledEvent) {
+			TransportEnabledEvent t = (TransportEnabledEvent) e;
+			// Poll the newly enabled transport
+			pollNow(t.getTransportId());
+		} else if (e instanceof TransportDisabledEvent) {
+			TransportDisabledEvent t = (TransportDisabledEvent) e;
+			// Cancel polling for the disabled transport
+			cancel(t.getTransportId());
+		}
+	}
+
+	private void connectToContact(ContactId c) {
+		for (SimplexPlugin s : pluginManager.getSimplexPlugins())
+			if (s.shouldPoll()) connectToContact(c, s);
+		for (DuplexPlugin d : pluginManager.getDuplexPlugins())
+			if (d.shouldPoll()) connectToContact(c, d);
+	}
+
+	private void connectToContact(ContactId c, TransportId t) {
+		Plugin p = pluginManager.getPlugin(t);
+		if (p instanceof SimplexPlugin && p.shouldPoll())
+			connectToContact(c, (SimplexPlugin) p);
+		else if (p instanceof DuplexPlugin && p.shouldPoll())
+			connectToContact(c, (DuplexPlugin) p);
+	}
+
+	private void connectToContact(ContactId c, SimplexPlugin p) {
+		ioExecutor.execute(() -> {
+			TransportId t = p.getId();
+			if (connectionRegistry.isConnected(c, t)) return;
+			try {
+				TransportProperties props =
+						transportPropertyManager.getRemoteProperties(c, t);
+				TransportConnectionWriter w = p.createWriter(props);
+				if (w != null)
+					connectionManager.manageOutgoingConnection(c, t, w);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	private void connectToContact(ContactId c, DuplexPlugin p) {
+		ioExecutor.execute(() -> {
+			TransportId t = p.getId();
+			if (connectionRegistry.isConnected(c, t)) return;
+			try {
+				TransportProperties props =
+						transportPropertyManager.getRemoteProperties(c, t);
+				DuplexTransportConnection d = p.createConnection(props);
+				if (d != null)
+					connectionManager.manageOutgoingConnection(c, t, d);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	private void reschedule(TransportId t) {
+		Plugin p = pluginManager.getPlugin(t);
+		if (p != null && p.shouldPoll())
+			schedule(p, p.getPollingInterval(), false);
+	}
+
+	private void pollNow(TransportId t) {
+		Plugin p = pluginManager.getPlugin(t);
+		// Randomise next polling interval
+		if (p != null && p.shouldPoll()) schedule(p, 0, true);
+	}
+
+	private void schedule(Plugin p, int delay, boolean randomiseNext) {
+		// Replace any later scheduled task for this plugin
+		long due = clock.currentTimeMillis() + delay;
+		TransportId t = p.getId();
+		lock.lock();
+		try {
+			ScheduledPollTask scheduled = tasks.get(t);
+			if (scheduled == null || due < scheduled.task.due) {
+				// If a later task exists, cancel it. If it's already started
+				// it will abort safely when it finds it's been replaced
+				if (scheduled != null) scheduled.future.cancel(false);
+				PollTask task = new PollTask(p, due, randomiseNext);
+				Future future = scheduler.schedule(() ->
+						ioExecutor.execute(task), delay, MILLISECONDS);
+				tasks.put(t, new ScheduledPollTask(task, future));
+			}
+		} finally {
+			lock.unlock();
+		}
+	}
+
+	private void cancel(TransportId t) {
+		lock.lock();
+		try {
+			ScheduledPollTask scheduled = tasks.remove(t);
+			if (scheduled != null) scheduled.future.cancel(false);
+		} finally {
+			lock.unlock();
+		}
+	}
+
+	@IoExecutor
+	private void poll(Plugin p) {
+		TransportId t = p.getId();
+		if (LOG.isLoggable(INFO)) LOG.info("Polling plugin " + t);
+		try {
+			Map<ContactId, TransportProperties> remote =
+					transportPropertyManager.getRemoteProperties(t);
+			Collection<ContactId> connected =
+					connectionRegistry.getConnectedContacts(t);
+			remote = new HashMap<>(remote);
+			remote.keySet().removeAll(connected);
+			if (!remote.isEmpty()) p.poll(remote);
+		} catch (DbException e) {
+			logException(LOG, WARNING, e);
+		}
+	}
+
+	private class ScheduledPollTask {
+
+		private final PollTask task;
+		private final Future future;
+
+		private ScheduledPollTask(PollTask task, Future future) {
+			this.task = task;
+			this.future = future;
+		}
+	}
+
+	private class PollTask implements Runnable {
+
+		private final Plugin plugin;
+		private final long due;
+		private final boolean randomiseNext;
+
+		private PollTask(Plugin plugin, long due, boolean randomiseNext) {
+			this.plugin = plugin;
+			this.due = due;
+			this.randomiseNext = randomiseNext;
+		}
+
+		@Override
+		@IoExecutor
+		public void run() {
+			lock.lock();
+			try {
+				TransportId t = plugin.getId();
+				ScheduledPollTask scheduled = tasks.get(t);
+				if (scheduled != null && scheduled.task != this)
+					return; // Replaced by another task
+				tasks.remove(t);
+			} finally {
+				lock.unlock();
+			}
+			int delay = plugin.getPollingInterval();
+			if (randomiseNext) delay = (int) (delay * random.nextDouble());
+			schedule(plugin, delay, false);
+			poll(plugin);
+		}
+	}
+}

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/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,
-		Service, ContactHook, IncomingMessageHook {
+class ClientVersioningManagerImpl implements ClientVersioningManager,
+		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,

bramble-core/src/test/java/org/briarproject/bramble/account/AccountManagerImplTest.java

@@ -3,6 +3,7 @@ package org.briarproject.bramble.account;
 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.test.BrambleMockTestCase;
@@ -24,7 +25,7 @@ import static junit.framework.Assert.assertFalse;
 import static junit.framework.Assert.assertNull;
 import static junit.framework.Assert.assertTrue;
 import static org.briarproject.bramble.test.TestUtils.deleteTestDirectory;
-import static org.briarproject.bramble.test.TestUtils.getLocalAuthor;
+import static org.briarproject.bramble.test.TestUtils.getIdentity;
 import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
 import static org.briarproject.bramble.test.TestUtils.getSecretKey;
 import static org.briarproject.bramble.test.TestUtils.getTestDirectory;
@@ -47,7 +48,8 @@ public class AccountManagerImplTest extends BrambleMockTestCase {
 	private final String encryptedKeyHex = toHexString(encryptedKey);
 	private final byte[] newEncryptedKey = getRandomBytes(123);
 	private final String newEncryptedKeyHex = toHexString(newEncryptedKey);
-	private final LocalAuthor localAuthor = getLocalAuthor();
+	private final Identity identity = getIdentity();
+	private final LocalAuthor localAuthor = identity.getLocalAuthor();
 	private final String authorName = localAuthor.getName();
 	private final String password = getRandomString(10);
 	private final String newPassword = getRandomString(10);
@@ -251,9 +253,9 @@ public class AccountManagerImplTest extends BrambleMockTestCase {
 	@Test
 	public void testCreateAccountStoresDbKey() throws Exception {
 		context.checking(new Expectations() {{
-			oneOf(identityManager).createLocalAuthor(authorName);
-			will(returnValue(localAuthor));
-			oneOf(identityManager).registerLocalAuthor(localAuthor);
+			oneOf(identityManager).createIdentity(authorName);
+			will(returnValue(identity));
+			oneOf(identityManager).registerIdentity(identity);
 			oneOf(crypto).generateSecretKey();
 			will(returnValue(key));
 			oneOf(crypto).encryptWithPassword(key.getBytes(), password);

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

@@ -47,6 +47,8 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	private final KeyManager keyManager = context.mock(KeyManager.class);
 	private final IdentityManager identityManager =
 			context.mock(IdentityManager.class);
+	private final PendingContactFactory pendingContactFactory =
+			context.mock(PendingContactFactory.class);
 	private final ContactManager contactManager;
 	private final Author remote = getAuthor();
 	private final LocalAuthor localAuthor = getLocalAuthor();
@@ -56,8 +58,8 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	private final ContactId contactId = contact.getId();
 
 	public ContactManagerImplTest() {
-		contactManager =
-				new ContactManagerImpl(db, keyManager, identityManager);
+		contactManager = new ContactManagerImpl(db, keyManager,
+				identityManager, pendingContactFactory);
 	}
 
 	@Test

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

@@ -0,0 +1,129 @@
+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.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.test.BrambleMockTestCase;
+import org.briarproject.bramble.util.Base32;
+import org.jmock.Expectations;
+import org.junit.Test;
+
+import java.security.GeneralSecurityException;
+
+import static java.lang.System.arraycopy;
+import static org.briarproject.bramble.api.contact.HandshakeLinkConstants.BASE32_LINK_BYTES;
+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.RAW_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.test.TestUtils.getRandomBytes;
+import static org.briarproject.bramble.test.TestUtils.getRandomId;
+import static org.briarproject.bramble.util.StringUtils.getRandomString;
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.fail;
+
+public class PendingContactFactoryImplTest extends BrambleMockTestCase {
+
+	private final CryptoComponent crypto = context.mock(CryptoComponent.class);
+	private final Clock clock = context.mock(Clock.class);
+	private final KeyParser keyParser = context.mock(KeyParser.class);
+	private final PublicKey publicKey = context.mock(PublicKey.class);
+
+	private final PendingContactFactory pendingContactFactory =
+			new PendingContactFactoryImpl(crypto, clock);
+	private final String alias = getRandomString(MAX_AUTHOR_NAME_LENGTH);
+	private final byte[] publicKeyBytes = getRandomBytes(RAW_LINK_BYTES - 1);
+	private final byte[] idBytes = getRandomId();
+	private final long timestamp = System.currentTimeMillis();
+
+	@Test(expected = FormatException.class)
+	public void testRejectsSyntacticallyInvalidLink() throws Exception {
+		pendingContactFactory.createPendingContact("briar://potato", alias);
+	}
+
+	@Test
+	public void testRejectsLinkWithUnknownFormatVersion() throws Exception {
+		String link = encodeLink(FORMAT_VERSION + 1);
+		try {
+			pendingContactFactory.createPendingContact(link, alias);
+			fail();
+		} catch (UnsupportedVersionException e) {
+			assertFalse(e.isTooOld());
+		}
+	}
+
+	@Test(expected = FormatException.class)
+	public void testRejectsLinkWithInvalidPublicKey() throws Exception {
+		context.checking(new Expectations() {{
+			oneOf(crypto).getAgreementKeyParser();
+			will(returnValue(keyParser));
+			oneOf(keyParser).parsePublicKey(with(equal(publicKeyBytes)));
+			will(throwException(new GeneralSecurityException()));
+		}});
+
+		pendingContactFactory.createPendingContact(encodeLink(), alias);
+	}
+
+	@Test
+	public void testAcceptsValidLinkWithoutPrefix() throws Exception {
+		testAcceptsValidLink(encodeLink());
+	}
+
+	@Test
+	public void testAcceptsValidLinkWithPrefix() throws Exception {
+		testAcceptsValidLink("briar://" + encodeLink());
+	}
+
+	@Test
+	public void testAcceptsValidLinkWithRubbish() throws Exception {
+		testAcceptsValidLink("before " + encodeLink() + " after");
+	}
+
+	@Test
+	public void testAcceptsValidLinkWithPrefixAndRubbish() throws Exception {
+		testAcceptsValidLink("before briar://" + encodeLink() + " after");
+	}
+
+	private void testAcceptsValidLink(String link) throws Exception {
+		context.checking(new Expectations() {{
+			oneOf(crypto).getAgreementKeyParser();
+			will(returnValue(keyParser));
+			oneOf(keyParser).parsePublicKey(with(equal(publicKeyBytes)));
+			will(returnValue(publicKey));
+			allowing(publicKey).getEncoded();
+			will(returnValue(publicKeyBytes));
+			oneOf(crypto).hash(ID_LABEL, publicKeyBytes);
+			will(returnValue(idBytes));
+			oneOf(clock).currentTimeMillis();
+			will(returnValue(timestamp));
+		}});
+
+		PendingContact p =
+				pendingContactFactory.createPendingContact(link, alias);
+		assertArrayEquals(idBytes, p.getId().getBytes());
+		assertArrayEquals(publicKeyBytes, p.getPublicKey());
+		assertEquals(alias, p.getAlias());
+		assertEquals(WAITING_FOR_CONNECTION, p.getState());
+		assertEquals(timestamp, p.getTimestamp());
+	}
+
+	private String encodeLink() {
+		return encodeLink(FORMAT_VERSION);
+	}
+
+	private String encodeLink(int formatVersion) {
+		byte[] rawLink = new byte[RAW_LINK_BYTES];
+		rawLink[0] = (byte) formatVersion;
+		arraycopy(publicKeyBytes, 0, rawLink, 1, publicKeyBytes.length);
+		String base32 = Base32.encode(rawLink).toLowerCase();
+		assertEquals(BASE32_LINK_BYTES, base32.length());
+		return base32;
+	}
+}

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

@@ -11,16 +11,17 @@ import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.Metadata;
 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;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.identity.Identity;
 import org.briarproject.bramble.api.identity.LocalAuthor;
-import org.briarproject.bramble.api.identity.event.LocalAuthorAddedEvent;
-import org.briarproject.bramble.api.identity.event.LocalAuthorRemovedEvent;
+import org.briarproject.bramble.api.identity.event.IdentityAddedEvent;
+import org.briarproject.bramble.api.identity.event.IdentityRemovedEvent;
 import org.briarproject.bramble.api.lifecycle.ShutdownManager;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.settings.Settings;
@@ -65,6 +66,7 @@ import java.util.concurrent.atomic.AtomicReference;
 import static java.util.Arrays.asList;
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonList;
+import static org.briarproject.bramble.api.crypto.CryptoConstants.MAX_AGREEMENT_PUBLIC_KEY_BYTES;
 import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
 import static org.briarproject.bramble.api.sync.Group.Visibility.VISIBLE;
@@ -77,8 +79,9 @@ import static org.briarproject.bramble.test.TestUtils.getAuthor;
 import static org.briarproject.bramble.test.TestUtils.getClientId;
 import static org.briarproject.bramble.test.TestUtils.getContact;
 import static org.briarproject.bramble.test.TestUtils.getGroup;
-import static org.briarproject.bramble.test.TestUtils.getLocalAuthor;
+import static org.briarproject.bramble.test.TestUtils.getIdentity;
 import static org.briarproject.bramble.test.TestUtils.getMessage;
+import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
 import static org.briarproject.bramble.test.TestUtils.getRandomId;
 import static org.briarproject.bramble.test.TestUtils.getSecretKey;
 import static org.briarproject.bramble.test.TestUtils.getTransportId;
@@ -104,6 +107,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 	private final GroupId groupId;
 	private final Group group;
 	private final Author author;
+	private final Identity identity;
 	private final LocalAuthor localAuthor;
 	private final String alias;
 	private final Message message, message1;
@@ -122,7 +126,8 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		group = getGroup(clientId, majorVersion);
 		groupId = group.getId();
 		author = getAuthor();
-		localAuthor = getLocalAuthor();
+		identity = getIdentity();
+		localAuthor = identity.getLocalAuthor();
 		message = getMessage(groupId);
 		message1 = getMessage(groupId);
 		messageId = message.getId();
@@ -157,15 +162,15 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			// startTransaction()
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
-			// registerLocalAuthor()
-			oneOf(database).containsLocalAuthor(txn, localAuthor.getId());
+			// addIdentity()
+			oneOf(database).containsIdentity(txn, localAuthor.getId());
 			will(returnValue(false));
-			oneOf(database).addLocalAuthor(txn, localAuthor);
-			oneOf(eventBus).broadcast(with(any(LocalAuthorAddedEvent.class)));
+			oneOf(database).addIdentity(txn, identity);
+			oneOf(eventBus).broadcast(with(any(IdentityAddedEvent.class)));
 			// addContact()
-			oneOf(database).containsLocalAuthor(txn, localAuthor.getId());
+			oneOf(database).containsIdentity(txn, localAuthor.getId());
 			will(returnValue(true));
-			oneOf(database).containsLocalAuthor(txn, author.getId());
+			oneOf(database).containsIdentity(txn, author.getId());
 			will(returnValue(false));
 			oneOf(database).containsContact(txn, author.getId(),
 					localAuthor.getId());
@@ -201,11 +206,11 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			will(returnValue(true));
 			oneOf(database).removeContact(txn, contactId);
 			oneOf(eventBus).broadcast(with(any(ContactRemovedEvent.class)));
-			// removeLocalAuthor()
-			oneOf(database).containsLocalAuthor(txn, localAuthor.getId());
+			// removeIdentity()
+			oneOf(database).containsIdentity(txn, localAuthor.getId());
 			will(returnValue(true));
-			oneOf(database).removeLocalAuthor(txn, localAuthor.getId());
-			oneOf(eventBus).broadcast(with(any(LocalAuthorRemovedEvent.class)));
+			oneOf(database).removeIdentity(txn, localAuthor.getId());
+			oneOf(eventBus).broadcast(with(any(IdentityRemovedEvent.class)));
 			// endTransaction()
 			oneOf(database).commitTransaction(txn);
 			// close()
@@ -216,7 +221,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 
 		assertFalse(db.open(key, null));
 		db.transaction(false, transaction -> {
-			db.addLocalAuthor(transaction, localAuthor);
+			db.addIdentity(transaction, identity);
 			assertEquals(contactId, db.addContact(transaction, author,
 					localAuthor.getId(), true));
 			assertEquals(singletonList(contact),
@@ -227,7 +232,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 					db.getGroups(transaction, clientId, majorVersion));
 			db.removeGroup(transaction, group);
 			db.removeContact(transaction, contactId);
-			db.removeLocalAuthor(transaction, localAuthor.getId());
+			db.removeIdentity(transaction, localAuthor.getId());
 		});
 		db.close();
 	}
@@ -432,16 +437,15 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 	}
 
 	@Test
-	public void testVariousMethodsThrowExceptionIfLocalAuthorIsMissing()
+	public void testVariousMethodsThrowExceptionIfIdentityIsMissing()
 			throws Exception {
 		context.checking(new Expectations() {{
-			// Check whether the pseudonym is in the DB (which it's not)
-			exactly(3).of(database).startTransaction();
+			// Check whether the identity is in the DB (which it's not)
+			exactly(4).of(database).startTransaction();
 			will(returnValue(txn));
-			exactly(3).of(database).containsLocalAuthor(txn,
-					localAuthor.getId());
+			exactly(4).of(database).containsIdentity(txn, localAuthor.getId());
 			will(returnValue(false));
-			exactly(3).of(database).abortTransaction(txn);
+			exactly(4).of(database).abortTransaction(txn);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
 				eventExecutor, shutdownManager);
@@ -451,23 +455,34 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 					db.addContact(transaction, author, localAuthor.getId(),
 							true));
 			fail();
-		} catch (NoSuchLocalAuthorException expected) {
+		} catch (NoSuchIdentityException expected) {
 			// Expected
 		}
 
 		try {
 			db.transaction(false, transaction ->
-					db.getLocalAuthor(transaction, localAuthor.getId()));
+					db.getIdentity(transaction, localAuthor.getId()));
 			fail();
-		} catch (NoSuchLocalAuthorException expected) {
+		} catch (NoSuchIdentityException expected) {
 			// Expected
 		}
 
 		try {
 			db.transaction(false, transaction ->
-					db.removeLocalAuthor(transaction, localAuthor.getId()));
+					db.removeIdentity(transaction, localAuthor.getId()));
 			fail();
-		} catch (NoSuchLocalAuthorException expected) {
+		} catch (NoSuchIdentityException expected) {
+			// Expected
+		}
+
+		try {
+			byte[] publicKey = getRandomBytes(MAX_AGREEMENT_PUBLIC_KEY_BYTES);
+			byte[] privateKey = getRandomBytes(123);
+			db.transaction(false, transaction ->
+					db.setHandshakeKeyPair(transaction, localAuthor.getId(),
+							publicKey, privateKey));
+			fail();
+		} catch (NoSuchIdentityException expected) {
 			// Expected
 		}
 	}
@@ -1403,10 +1418,10 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
-			oneOf(database).containsLocalAuthor(txn, localAuthor.getId());
+			oneOf(database).containsIdentity(txn, localAuthor.getId());
 			will(returnValue(true));
 			// Contact is a local identity
-			oneOf(database).containsLocalAuthor(txn, author.getId());
+			oneOf(database).containsIdentity(txn, author.getId());
 			will(returnValue(true));
 			oneOf(database).abortTransaction(txn);
 		}});
@@ -1429,9 +1444,9 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		context.checking(new Expectations() {{
 			oneOf(database).startTransaction();
 			will(returnValue(txn));
-			oneOf(database).containsLocalAuthor(txn, localAuthor.getId());
+			oneOf(database).containsIdentity(txn, localAuthor.getId());
 			will(returnValue(true));
-			oneOf(database).containsLocalAuthor(txn, author.getId());
+			oneOf(database).containsIdentity(txn, author.getId());
 			will(returnValue(false));
 			// Contact already exists for this local identity
 			oneOf(database).containsContact(txn, author.getId(),
@@ -1454,7 +1469,6 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 	}
 
 	@Test
-	@SuppressWarnings("unchecked")
 	public void testMessageDependencies() throws Exception {
 		int shutdownHandle = 12345;
 		MessageId messageId2 = new MessageId(getRandomId());

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

@@ -5,6 +5,7 @@ import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Metadata;
 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.sync.ClientId;
 import org.briarproject.bramble.api.sync.Group;
@@ -37,7 +38,7 @@ import static org.briarproject.bramble.api.sync.validation.MessageState.DELIVERE
 import static org.briarproject.bramble.test.TestUtils.deleteTestDirectory;
 import static org.briarproject.bramble.test.TestUtils.getAuthor;
 import static org.briarproject.bramble.test.TestUtils.getGroup;
-import static org.briarproject.bramble.test.TestUtils.getLocalAuthor;
+import static org.briarproject.bramble.test.TestUtils.getIdentity;
 import static org.briarproject.bramble.test.TestUtils.getMessage;
 import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
 import static org.briarproject.bramble.test.TestUtils.getRandomId;
@@ -161,11 +162,11 @@ public abstract class DatabasePerformanceTest extends BrambleTestCase {
 	}
 
 	@Test
-	public void testContainsLocalAuthor() throws Exception {
-		String name = "containsLocalAuthor(T, AuthorId)";
+	public void testContainsIdentity() throws Exception {
+		String name = "containsIdentity(T, AuthorId)";
 		benchmark(name, db -> {
 			Connection txn = db.startTransaction();
-			db.containsLocalAuthor(txn, localAuthor.getId());
+			db.containsIdentity(txn, localAuthor.getId());
 			db.commitTransaction(txn);
 		});
 	}
@@ -295,21 +296,21 @@ public abstract class DatabasePerformanceTest extends BrambleTestCase {
 	}
 
 	@Test
-	public void testGetLocalAuthor() throws Exception {
-		String name = "getLocalAuthor(T, AuthorId)";
+	public void testGetIdentity() throws Exception {
+		String name = "getIdentity(T, AuthorId)";
 		benchmark(name, db -> {
 			Connection txn = db.startTransaction();
-			db.getLocalAuthor(txn, localAuthor.getId());
+			db.getIdentity(txn, localAuthor.getId());
 			db.commitTransaction(txn);
 		});
 	}
 
 	@Test
-	public void testGetLocalAuthors() throws Exception {
-		String name = "getLocalAuthors(T)";
+	public void testGetIdentities() throws Exception {
+		String name = "getIdentities(T)";
 		benchmark(name, db -> {
 			Connection txn = db.startTransaction();
-			db.getLocalAuthors(txn);
+			db.getIdentities(txn);
 			db.commitTransaction(txn);
 		});
 	}
@@ -531,7 +532,8 @@ public abstract class DatabasePerformanceTest extends BrambleTestCase {
 	}
 
 	void populateDatabase(Database<Connection> db) throws DbException {
-		localAuthor = getLocalAuthor();
+		Identity identity = getIdentity();
+		localAuthor = identity.getLocalAuthor();
 		clientIds = new ArrayList<>();
 		contacts = new ArrayList<>();
 		groups = new ArrayList<>();
@@ -543,7 +545,7 @@ public abstract class DatabasePerformanceTest extends BrambleTestCase {
 		for (int i = 0; i < CLIENTS; i++) clientIds.add(getClientId());
 
 		Connection txn = db.startTransaction();
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		for (int i = 0; i < CONTACTS; i++) {
 			ContactId c = db.addContact(txn, getAuthor(), localAuthor.getId(),
 					random.nextBoolean());

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

@@ -9,6 +9,7 @@ import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.MessageDeletedException;
 import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.identity.Author;
+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.settings.Settings;
@@ -57,6 +58,7 @@ import static java.util.Collections.singletonList;
 import static java.util.Collections.singletonMap;
 import static java.util.concurrent.TimeUnit.SECONDS;
 import static org.briarproject.bramble.api.contact.PendingContactState.FAILED;
+import static org.briarproject.bramble.api.crypto.CryptoConstants.MAX_AGREEMENT_PUBLIC_KEY_BYTES;
 import static org.briarproject.bramble.api.db.Metadata.REMOVE;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
 import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
@@ -73,9 +75,10 @@ import static org.briarproject.bramble.test.TestUtils.deleteTestDirectory;
 import static org.briarproject.bramble.test.TestUtils.getAuthor;
 import static org.briarproject.bramble.test.TestUtils.getClientId;
 import static org.briarproject.bramble.test.TestUtils.getGroup;
-import static org.briarproject.bramble.test.TestUtils.getLocalAuthor;
+import static org.briarproject.bramble.test.TestUtils.getIdentity;
 import static org.briarproject.bramble.test.TestUtils.getMessage;
 import static org.briarproject.bramble.test.TestUtils.getPendingContact;
+import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
 import static org.briarproject.bramble.test.TestUtils.getRandomId;
 import static org.briarproject.bramble.test.TestUtils.getSecretKey;
 import static org.briarproject.bramble.test.TestUtils.getTestDirectory;
@@ -103,6 +106,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 	private final int majorVersion;
 	private final Group group;
 	private final Author author;
+	private final Identity identity;
 	private final LocalAuthor localAuthor;
 	private final Message message;
 	private final MessageId messageId;
@@ -119,7 +123,8 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		group = getGroup(clientId, majorVersion);
 		groupId = group.getId();
 		author = getAuthor();
-		localAuthor = getLocalAuthor();
+		identity = getIdentity();
+		localAuthor = identity.getLocalAuthor();
 		message = getMessage(groupId);
 		messageId = message.getId();
 		transportId = getTransportId();
@@ -145,7 +150,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Database<Connection> db = open(false);
 		Connection txn = db.startTransaction();
 		assertFalse(db.containsContact(txn, contactId));
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		assertTrue(db.containsContact(txn, contactId));
@@ -208,7 +213,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact, a shared group and a shared message
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addGroup(txn, group);
@@ -239,7 +244,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact, a shared group and a shared but unvalidated message
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addGroup(txn, group);
@@ -284,7 +289,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact, an invisible group and a shared message
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addGroup(txn, group);
@@ -335,7 +340,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact, a shared group and an unshared message
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addGroup(txn, group);
@@ -366,7 +371,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact, a shared group and a shared message
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addGroup(txn, group);
@@ -393,7 +398,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact and a visible group
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addGroup(txn, group);
@@ -434,7 +439,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact, a shared group and a shared message
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addGroup(txn, group);
@@ -566,7 +571,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact and a shared group
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addGroup(txn, group);
@@ -586,7 +591,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 
@@ -604,7 +609,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact, an invisible group and a message
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addGroup(txn, group);
@@ -623,7 +628,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact and a group
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addGroup(txn, group);
@@ -675,7 +680,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertEquals(emptyList(), db.getTransportKeys(txn, transportId));
 
 		// Add the contact, the transport and the transport keys
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addTransport(txn, transportId, 123);
@@ -776,7 +781,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertEquals(emptyList(), db.getHandshakeKeys(txn, transportId));
 
 		// Add the contact, the transport and the handshake keys
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addTransport(txn, transportId, 123);
@@ -929,7 +934,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add the contact, transport and transport keys
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addTransport(txn, transportId, 123);
@@ -973,7 +978,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add the contact, transport and handshake keys
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addTransport(txn, transportId, 123);
@@ -1020,7 +1025,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add the contact, transport and transport keys
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addTransport(txn, transportId, 123);
@@ -1067,7 +1072,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add the contact, transport and handshake keys
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addTransport(txn, transportId, 123);
@@ -1109,14 +1114,15 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Database<Connection> db = open(false);
 		Connection txn = db.startTransaction();
 
-		// Add a local author - no contacts should be associated
-		db.addLocalAuthor(txn, localAuthor);
+		// Add an identity for a local author - no contacts should be
+		// associated
+		db.addIdentity(txn, identity);
 
 		// Add a contact associated with the local author
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 
-		// Ensure contact is returned from database by Author ID
+		// Ensure contact is returned from database by author ID
 		Collection<Contact> contacts =
 				db.getContactsByAuthorId(txn, author.getId());
 		assertEquals(1, contacts.size());
@@ -1136,8 +1142,9 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Database<Connection> db = open(false);
 		Connection txn = db.startTransaction();
 
-		// Add a local author - no contacts should be associated
-		db.addLocalAuthor(txn, localAuthor);
+		// Add an identity for a local author - no contacts should be
+		// associated
+		db.addIdentity(txn, identity);
 		Collection<ContactId> contacts =
 				db.getContacts(txn, localAuthor.getId());
 		assertEquals(emptyList(), contacts);
@@ -1148,8 +1155,8 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		contacts = db.getContacts(txn, localAuthor.getId());
 		assertEquals(singletonList(contactId), contacts);
 
-		// Remove the local author - the contact should be removed
-		db.removeLocalAuthor(txn, localAuthor.getId());
+		// Remove the identity - the contact should be removed
+		db.removeIdentity(txn, localAuthor.getId());
 		contacts = db.getContacts(txn, localAuthor.getId());
 		assertEquals(emptyList(), contacts);
 		assertFalse(db.containsContact(txn, contactId));
@@ -1164,7 +1171,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact - initially there should be no offered messages
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		assertEquals(0, db.countOfferedMessages(txn, contactId));
@@ -1748,7 +1755,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact, a shared group and a shared message
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addGroup(txn, group);
@@ -1850,14 +1857,15 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 	@Test
 	public void testDifferentLocalAuthorsCanHaveTheSameContact()
 			throws Exception {
-		LocalAuthor localAuthor1 = getLocalAuthor();
+		Identity identity1 = getIdentity();
+		LocalAuthor localAuthor1 = identity1.getLocalAuthor();
 
 		Database<Connection> db = open(false);
 		Connection txn = db.startTransaction();
 
-		// Add two local authors
-		db.addLocalAuthor(txn, localAuthor);
-		db.addLocalAuthor(txn, localAuthor1);
+		// Add identities for two local authors
+		db.addIdentity(txn, identity);
+		db.addIdentity(txn, identity1);
 
 		// Add the same contact for each local author
 		ContactId contactId =
@@ -1881,7 +1889,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact, a shared group and a shared message
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addGroup(txn, group);
@@ -1935,7 +1943,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 
@@ -1992,7 +2000,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact, a group and a message
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addGroup(txn, group);
@@ -2076,7 +2084,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact, a shared group and a shared message
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addGroup(txn, group);
@@ -2121,7 +2129,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		Connection txn = db.startTransaction();
 
 		// Add a contact, a shared group and a shared message
-		db.addLocalAuthor(txn, localAuthor);
+		db.addIdentity(txn, identity);
 		assertEquals(contactId,
 				db.addContact(txn, author, localAuthor.getId(), true));
 		db.addGroup(txn, group);
@@ -2237,6 +2245,30 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		db.close();
 	}
 
+	@Test
+	public void testSetHandshakeKeyPair() throws Exception {
+		Identity withoutKeys =
+				new Identity(localAuthor, null, null, identity.getTimeCreated());
+		assertFalse(withoutKeys.hasHandshakeKeyPair());
+		byte[] publicKey = getRandomBytes(MAX_AGREEMENT_PUBLIC_KEY_BYTES);
+		byte[] privateKey = getRandomBytes(123);
+
+		Database<Connection> db = open(false);
+		Connection txn = db.startTransaction();
+
+		db.addIdentity(txn, withoutKeys);
+		Identity retrieved = db.getIdentity(txn, localAuthor.getId());
+		assertFalse(retrieved.hasHandshakeKeyPair());
+		db.setHandshakeKeyPair(txn, localAuthor.getId(), publicKey, privateKey);
+		retrieved = db.getIdentity(txn, localAuthor.getId());
+		assertTrue(retrieved.hasHandshakeKeyPair());
+		assertArrayEquals(publicKey, retrieved.getHandshakePublicKey());
+		assertArrayEquals(privateKey, retrieved.getHandshakePrivateKey());
+
+		db.commitTransaction(txn);
+		db.close();
+	}
+
 	private Database<Connection> open(boolean resume) throws Exception {
 		return open(resume, new TestMessageFactory(), new SystemClock());
 	}

bramble-core/src/test/java/org/briarproject/bramble/identity/IdentityManagerImplTest.java

@@ -8,18 +8,17 @@ 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.IdentityManager;
+import org.briarproject.bramble.api.identity.Identity;
 import org.briarproject.bramble.api.identity.LocalAuthor;
+import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.test.BrambleMockTestCase;
 import org.briarproject.bramble.test.DbExpectations;
 import org.jmock.Expectations;
 import org.junit.Before;
 import org.junit.Test;
 
-import java.util.Collection;
-import java.util.Collections;
-
-import static org.briarproject.bramble.test.TestUtils.getLocalAuthor;
+import static java.util.Collections.singletonList;
+import static org.briarproject.bramble.test.TestUtils.getIdentity;
 import static org.junit.Assert.assertEquals;
 
 public class IdentityManagerImplTest extends BrambleMockTestCase {
@@ -28,67 +27,100 @@ public class IdentityManagerImplTest extends BrambleMockTestCase {
 	private final CryptoComponent crypto = context.mock(CryptoComponent.class);
 	private final AuthorFactory authorFactory =
 			context.mock(AuthorFactory.class);
-	private final PublicKey publicKey = context.mock(PublicKey.class);
-	private final PrivateKey privateKey = context.mock(PrivateKey.class);
+	private final Clock clock = context.mock(Clock.class);
+	private final PublicKey handshakePublicKey = context.mock(PublicKey.class);
+	private final PrivateKey handshakePrivateKey =
+			context.mock(PrivateKey.class);
 
 	private final Transaction txn = new Transaction(null, false);
-	private final LocalAuthor localAuthor = getLocalAuthor();
-	private final Collection<LocalAuthor> localAuthors =
-			Collections.singletonList(localAuthor);
-	private final String authorName = localAuthor.getName();
-	private final KeyPair keyPair = new KeyPair(publicKey, privateKey);
-	private final byte[] publicKeyBytes = localAuthor.getPublicKey();
-	private final byte[] privateKeyBytes = localAuthor.getPrivateKey();
-	private IdentityManager identityManager;
+	private final Identity identityWithKeys = getIdentity();
+	private final LocalAuthor localAuthor = identityWithKeys.getLocalAuthor();
+	private final Identity identityWithoutKeys = new Identity(localAuthor,
+			null, null, identityWithKeys.getTimeCreated());
+	private final KeyPair handshakeKeyPair =
+			new KeyPair(handshakePublicKey, handshakePrivateKey);
+	private final byte[] handshakePublicKeyBytes =
+			identityWithKeys.getHandshakePublicKey();
+	private final byte[] handshakePrivateKeyBytes =
+			identityWithKeys.getHandshakePrivateKey();
+
+	private IdentityManagerImpl identityManager;
 
 	@Before
 	public void setUp() {
-		identityManager = new IdentityManagerImpl(db, crypto, authorFactory);
+		identityManager =
+				new IdentityManagerImpl(db, crypto, authorFactory, clock);
 	}
 
 	@Test
-	public void testCreateLocalAuthor() {
+	public void testOpenDatabaseIdentityRegistered() throws Exception {
 		context.checking(new Expectations() {{
-			oneOf(crypto).generateSignatureKeyPair();
-			will(returnValue(keyPair));
-			oneOf(publicKey).getEncoded();
-			will(returnValue(publicKeyBytes));
-			oneOf(privateKey).getEncoded();
-			will(returnValue(privateKeyBytes));
-			oneOf(authorFactory).createLocalAuthor(authorName,
-					publicKeyBytes, privateKeyBytes);
-			will(returnValue(localAuthor));
+			oneOf(db).addIdentity(txn, identityWithKeys);
 		}});
 
-		assertEquals(localAuthor,
-				identityManager.createLocalAuthor(authorName));
+		identityManager.registerIdentity(identityWithKeys);
+		identityManager.onDatabaseOpened(txn);
 	}
 
 	@Test
-	public void testRegisterAndStoreLocalAuthor() throws Exception {
-		context.checking(new DbExpectations() {{
-			oneOf(db).transaction(with(false), withDbRunnable(txn));
-			oneOf(db).addLocalAuthor(txn, localAuthor);
+	public void testOpenDatabaseHandshakeKeysGenerated() throws Exception {
+		context.checking(new Expectations() {{
+			oneOf(db).getIdentities(txn);
+			will(returnValue(singletonList(identityWithoutKeys)));
+			oneOf(crypto).generateAgreementKeyPair();
+			will(returnValue(handshakeKeyPair));
+			oneOf(handshakePublicKey).getEncoded();
+			will(returnValue(handshakePublicKeyBytes));
+			oneOf(handshakePrivateKey).getEncoded();
+			will(returnValue(handshakePrivateKeyBytes));
+			oneOf(db).setHandshakeKeyPair(txn, localAuthor.getId(),
+					handshakePublicKeyBytes, handshakePrivateKeyBytes);
 		}});
 
-		identityManager.registerLocalAuthor(localAuthor);
+		identityManager.onDatabaseOpened(txn);
+	}
+
+	@Test
+	public void testOpenDatabaseNoHandshakeKeysGenerated() throws Exception {
+		context.checking(new Expectations() {{
+			oneOf(db).getIdentities(txn);
+			will(returnValue(singletonList(identityWithKeys)));
+		}});
+
+		identityManager.onDatabaseOpened(txn);
+	}
+
+	@Test
+	public void testGetLocalAuthorIdentityRegistered() throws DbException {
+		identityManager.registerIdentity(identityWithKeys);
 		assertEquals(localAuthor, identityManager.getLocalAuthor());
-		identityManager.storeLocalAuthor();
 	}
 
 	@Test
-	public void testGetLocalAuthor() throws Exception {
+	public void testGetLocalAuthorHandshakeKeysGenerated() throws Exception {
 		context.checking(new DbExpectations() {{
 			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			oneOf(db).getLocalAuthors(txn);
-			will(returnValue(localAuthors));
+			oneOf(db).getIdentities(txn);
+			will(returnValue(singletonList(identityWithoutKeys)));
+			oneOf(crypto).generateAgreementKeyPair();
+			will(returnValue(handshakeKeyPair));
+			oneOf(handshakePublicKey).getEncoded();
+			will(returnValue(handshakePublicKeyBytes));
+			oneOf(handshakePrivateKey).getEncoded();
+			will(returnValue(handshakePrivateKeyBytes));
 		}});
+
 		assertEquals(localAuthor, identityManager.getLocalAuthor());
 	}
 
 	@Test
-	public void testGetCachedLocalAuthor() throws DbException {
-		identityManager.registerLocalAuthor(localAuthor);
+	public void testGetLocalAuthorNoHandshakeKeysGenerated() throws Exception {
+		context.checking(new DbExpectations() {{
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
+			oneOf(db).getIdentities(txn);
+			will(returnValue(singletonList(identityWithKeys)));
+		}});
+
 		assertEquals(localAuthor, identityManager.getLocalAuthor());
 	}
 

bramble-core/src/test/java/org/briarproject/bramble/keyagreement/PayloadParserImplTest.java

@@ -2,11 +2,11 @@ package org.briarproject.bramble.keyagreement;
 
 import org.briarproject.bramble.api.Bytes;
 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.UnsupportedVersionException;
 import org.briarproject.bramble.test.BrambleMockTestCase;
 import org.jmock.Expectations;
 import org.junit.Test;

bramble-core/src/test/java/org/briarproject/bramble/lifecycle/LifecycleManagerImplTest.java

@@ -0,0 +1,53 @@
+package org.briarproject.bramble.lifecycle;
+
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager.OpenDatabaseHook;
+import org.briarproject.bramble.api.lifecycle.event.LifecycleEvent;
+import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.briarproject.bramble.test.DbExpectations;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static junit.framework.TestCase.assertTrue;
+import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.SUCCESS;
+import static org.briarproject.bramble.test.TestUtils.getSecretKey;
+import static org.junit.Assert.assertEquals;
+
+public class LifecycleManagerImplTest extends BrambleMockTestCase {
+
+	private final DatabaseComponent db = context.mock(DatabaseComponent.class);
+	private final EventBus eventBus = context.mock(EventBus.class);
+
+	private final SecretKey dbKey = getSecretKey();
+
+	private LifecycleManagerImpl lifecycleManager;
+
+	@Before
+	public void setUp() {
+		lifecycleManager = new LifecycleManagerImpl(db, eventBus);
+	}
+
+	@Test
+	public void testOpenDatabaseHooksAreCalledAtStartup() throws Exception {
+		Transaction txn = new Transaction(null, false);
+		AtomicBoolean called = new AtomicBoolean(false);
+		OpenDatabaseHook hook = transaction -> called.set(true);
+
+		context.checking(new DbExpectations() {{
+			oneOf(db).open(dbKey, lifecycleManager);
+			will(returnValue(false));
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
+			allowing(eventBus).broadcast(with(any(LifecycleEvent.class)));
+		}});
+
+		lifecycleManager.registerOpenDatabaseHook(hook);
+
+		assertEquals(SUCCESS, lifecycleManager.startServices(dbKey));
+		assertTrue(called.get());
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/plugin/PluginManagerImplTest.java

@@ -2,7 +2,6 @@ package org.briarproject.bramble.plugin;
 
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.plugin.ConnectionManager;
-import org.briarproject.bramble.api.plugin.ConnectionRegistry;
 import org.briarproject.bramble.api.plugin.PluginConfig;
 import org.briarproject.bramble.api.plugin.PluginException;
 import org.briarproject.bramble.api.plugin.TransportId;
@@ -14,18 +13,15 @@ import org.briarproject.bramble.api.plugin.simplex.SimplexPluginCallback;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
 import org.briarproject.bramble.api.properties.TransportPropertyManager;
 import org.briarproject.bramble.api.settings.SettingsManager;
-import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.test.BrambleTestCase;
 import org.jmock.Expectations;
 import org.jmock.Mockery;
 import org.jmock.lib.concurrent.Synchroniser;
 import org.junit.Test;
 
-import java.security.SecureRandom;
 import java.util.Arrays;
 import java.util.concurrent.Executor;
 import java.util.concurrent.Executors;
-import java.util.concurrent.ScheduledExecutorService;
 
 import static org.briarproject.bramble.test.TestUtils.getTransportId;
 
@@ -37,16 +33,10 @@ public class PluginManagerImplTest extends BrambleTestCase {
 			setThreadingPolicy(new Synchroniser());
 		}};
 		Executor ioExecutor = Executors.newSingleThreadExecutor();
-		ScheduledExecutorService scheduler =
-				context.mock(ScheduledExecutorService.class);
-		SecureRandom random = new SecureRandom();
-		Clock clock = context.mock(Clock.class);
 		EventBus eventBus = context.mock(EventBus.class);
 		PluginConfig pluginConfig = context.mock(PluginConfig.class);
 		ConnectionManager connectionManager =
 				context.mock(ConnectionManager.class);
-		ConnectionRegistry connectionRegistry =
-				context.mock(ConnectionRegistry.class);
 		SettingsManager settingsManager =
 				context.mock(SettingsManager.class);
 		TransportPropertyManager transportPropertyManager =
@@ -122,9 +112,9 @@ public class PluginManagerImplTest extends BrambleTestCase {
 			oneOf(duplexPlugin).stop();
 		}});
 
-		PluginManagerImpl p = new PluginManagerImpl(ioExecutor, scheduler,
-				eventBus, pluginConfig, connectionManager, connectionRegistry,
-				settingsManager, transportPropertyManager, random, clock);
+		PluginManagerImpl p = new PluginManagerImpl(ioExecutor, eventBus,
+				pluginConfig, connectionManager, settingsManager,
+				transportPropertyManager);
 
 		// Two plugins should be started and stopped
 		p.startService();

bramble-core/src/test/java/org/briarproject/bramble/plugin/PollerImplTest.java

@@ -23,6 +23,7 @@ import org.briarproject.bramble.test.ImmediateExecutor;
 import org.briarproject.bramble.test.RunAction;
 import org.jmock.Expectations;
 import org.jmock.lib.legacy.ClassImposteriser;
+import org.junit.Before;
 import org.junit.Test;
 
 import java.security.SecureRandom;
@@ -39,7 +40,7 @@ import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static org.briarproject.bramble.test.TestUtils.getContactId;
 import static org.briarproject.bramble.test.TestUtils.getTransportId;
 
-public class PollerTest extends BrambleMockTestCase {
+public class PollerImplTest extends BrambleMockTestCase {
 
 	private final ScheduledExecutorService scheduler =
 			context.mock(ScheduledExecutorService.class);
@@ -62,11 +63,20 @@ public class PollerTest extends BrambleMockTestCase {
 	private final int pollingInterval = 60 * 1000;
 	private final long now = System.currentTimeMillis();
 
-	public PollerTest() {
+	private PollerImpl poller;
+
+	public PollerImplTest() {
 		context.setImposteriser(ClassImposteriser.INSTANCE);
 		random = context.mock(SecureRandom.class);
 	}
 
+	@Before
+	public void setUp() {
+		poller = new PollerImpl(ioExecutor, scheduler, connectionManager,
+				connectionRegistry, pluginManager, transportPropertyManager,
+				random, clock);
+	}
+
 	@Test
 	public void testConnectOnContactAdded() throws Exception {
 		// Two simplex plugins: one supports polling, the other doesn't
@@ -140,11 +150,7 @@ public class PollerTest extends BrambleMockTestCase {
 			will(returnValue(false));
 		}});
 
-		Poller p = new Poller(ioExecutor, scheduler, connectionManager,
-				connectionRegistry, pluginManager, transportPropertyManager,
-				random, clock);
-
-		p.eventOccurred(new ContactAddedEvent(contactId));
+		poller.eventOccurred(new ContactAddedEvent(contactId));
 	}
 
 	@Test
@@ -194,11 +200,7 @@ public class PollerTest extends BrambleMockTestCase {
 					transportId, duplexConnection);
 		}});
 
-		Poller p = new Poller(ioExecutor, scheduler, connectionManager,
-				connectionRegistry, pluginManager, transportPropertyManager,
-				random, clock);
-
-		p.eventOccurred(new ConnectionClosedEvent(contactId, transportId,
+		poller.eventOccurred(new ConnectionClosedEvent(contactId, transportId,
 				false));
 	}
 
@@ -225,11 +227,7 @@ public class PollerTest extends BrambleMockTestCase {
 			will(returnValue(future));
 		}});
 
-		Poller p = new Poller(ioExecutor, scheduler, connectionManager,
-				connectionRegistry, pluginManager, transportPropertyManager,
-				random, clock);
-
-		p.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
+		poller.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
 				false));
 	}
 
@@ -269,13 +267,9 @@ public class PollerTest extends BrambleMockTestCase {
 			will(returnValue(now + 1));
 		}});
 
-		Poller p = new Poller(ioExecutor, scheduler, connectionManager,
-				connectionRegistry, pluginManager, transportPropertyManager,
-				random, clock);
-
-		p.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
+		poller.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
 				false));
-		p.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
+		poller.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
 				false));
 	}
 
@@ -318,13 +312,9 @@ public class PollerTest extends BrambleMockTestCase {
 					with((long) pollingInterval - 2), with(MILLISECONDS));
 		}});
 
-		Poller p = new Poller(ioExecutor, scheduler, connectionManager,
-				connectionRegistry, pluginManager, transportPropertyManager,
-				random, clock);
-
-		p.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
+		poller.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
 				false));
-		p.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
+		poller.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
 				false));
 	}
 
@@ -367,11 +357,7 @@ public class PollerTest extends BrambleMockTestCase {
 			oneOf(plugin).poll(singletonMap(contactId, properties));
 		}});
 
-		Poller p = new Poller(ioExecutor, scheduler, connectionManager,
-				connectionRegistry, pluginManager, transportPropertyManager,
-				random, clock);
-
-		p.eventOccurred(new TransportEnabledEvent(transportId));
+		poller.eventOccurred(new TransportEnabledEvent(transportId));
 	}
 
 	@Test
@@ -412,11 +398,7 @@ public class PollerTest extends BrambleMockTestCase {
 			// All contacts are connected, so don't poll the plugin
 		}});
 
-		Poller p = new Poller(ioExecutor, scheduler, connectionManager,
-				connectionRegistry, pluginManager, transportPropertyManager,
-				random, clock);
-
-		p.eventOccurred(new TransportEnabledEvent(transportId));
+		poller.eventOccurred(new TransportEnabledEvent(transportId));
 	}
 
 	@Test
@@ -442,11 +424,7 @@ public class PollerTest extends BrambleMockTestCase {
 			oneOf(future).cancel(false);
 		}});
 
-		Poller p = new Poller(ioExecutor, scheduler, connectionManager,
-				connectionRegistry, pluginManager, transportPropertyManager,
-				random, clock);
-
-		p.eventOccurred(new TransportEnabledEvent(transportId));
-		p.eventOccurred(new TransportDisabledEvent(transportId));
+		poller.eventOccurred(new TransportEnabledEvent(transportId));
+		poller.eventOccurred(new TransportDisabledEvent(transportId));
 	}
 }

bramble-core/src/test/java/org/briarproject/bramble/properties/TransportPropertyManagerImplTest.java

@@ -115,7 +115,7 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 				1, true, true);
 
 		TransportPropertyManagerImpl t = createInstance();
-		t.createLocalState(txn);
+		t.onDatabaseOpened(txn);
 	}
 
 	@Test
@@ -129,7 +129,7 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		}});
 
 		TransportPropertyManagerImpl t = createInstance();
-		t.createLocalState(txn);
+		t.onDatabaseOpened(txn);
 	}
 
 	@Test

bramble-core/src/test/java/org/briarproject/bramble/test/TestLifecycleModule.java

@@ -6,7 +6,6 @@ import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.lifecycle.Service;
 import org.briarproject.bramble.api.lifecycle.ShutdownManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.sync.Client;
 
 import java.util.concurrent.Executor;
 import java.util.concurrent.ExecutorService;
@@ -32,7 +31,7 @@ public class TestLifecycleModule {
 			}
 
 			@Override
-			public void registerClient(Client c) {
+			public void registerOpenDatabaseHook(OpenDatabaseHook hook) {
 			}
 
 			@Override

bramble-core/src/test/java/org/briarproject/bramble/util/Base32Test.java

@@ -0,0 +1,71 @@
+package org.briarproject.bramble.util;
+
+import org.briarproject.bramble.test.BrambleTestCase;
+import org.junit.Test;
+
+import java.util.Random;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+
+public class Base32Test extends BrambleTestCase {
+
+	// Test vectors from RFC 4648
+	// https://tools.ietf.org/html/rfc4648#section-10
+
+	@Test
+	public void testEncoding() {
+		assertEquals("", Base32.encode(new byte[0]));
+		assertEquals("MY", Base32.encode(new byte[] {'f'}));
+		assertEquals("MZXQ", Base32.encode(new byte[] {'f', 'o'}));
+		assertEquals("MZXW6", Base32.encode(new byte[] {'f', 'o', 'o'}));
+		assertEquals("MZXW6YQ", Base32.encode(new byte[] {'f', 'o', 'o', 'b'}));
+		assertEquals("MZXW6YTB",
+				Base32.encode(new byte[] {'f', 'o', 'o', 'b', 'a'}));
+		assertEquals("MZXW6YTBOI",
+				Base32.encode(new byte[] {'f', 'o', 'o', 'b', 'a', 'r'}));
+	}
+
+	@Test
+	public void testStrictDecoding() {
+		testDecoding(true);
+	}
+
+	@Test
+	public void testNonStrictDecoding() {
+		testDecoding(false);
+	}
+
+	private void testDecoding(boolean strict) {
+		assertArrayEquals(new byte[0], Base32.decode("", strict));
+		assertArrayEquals(new byte[] {'f'}, Base32.decode("MY", strict));
+		assertArrayEquals(new byte[] {'f', 'o'}, Base32.decode("MZXQ", strict));
+		assertArrayEquals(new byte[] {'f', 'o', 'o'},
+				Base32.decode("MZXW6", strict));
+		assertArrayEquals(new byte[] {'f', 'o', 'o', 'b'},
+				Base32.decode("MZXW6YQ", strict));
+		assertArrayEquals(new byte[] {'f', 'o', 'o', 'b', 'a'},
+				Base32.decode("MZXW6YTB", strict));
+		assertArrayEquals(new byte[] {'f', 'o', 'o', 'b', 'a', 'r'},
+				Base32.decode("MZXW6YTBOI", strict));
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void testStrictDecodingRejectsNonZeroUnusedBits() {
+		Base32.decode("MZ", true);
+	}
+
+	@Test
+	public void testNonStrictDecodingAcceptsNonZeroUnusedBits() {
+		assertArrayEquals(new byte[] {'f'}, Base32.decode("MZ", false));
+	}
+
+	@Test
+	public void testRoundTrip() {
+		Random random = new Random();
+		byte[] data = new byte[100 + random.nextInt(100)];
+		random.nextBytes(data);
+		assertArrayEquals(data, Base32.decode(Base32.encode(data), true));
+		assertArrayEquals(data, Base32.decode(Base32.encode(data), false));
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/versioning/ClientVersioningManagerImplTest.java

@@ -83,7 +83,7 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 		expectAddingContact();
 
 		ClientVersioningManagerImpl c = createInstance();
-		c.createLocalState(txn);
+		c.onDatabaseOpened(txn);
 	}
 
 	@Test
@@ -95,7 +95,7 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 		}});
 
 		ClientVersioningManagerImpl c = createInstance();
-		c.createLocalState(txn);
+		c.onDatabaseOpened(txn);
 	}
 
 	@Test

bramble-core/witness.gradle

@@ -2,15 +2,15 @@ dependencyVerification {
     verify = [
         'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
         'com.google.code.findbugs:jsr305:1.3.9:jsr305-1.3.9.jar:905721a0eea90a81534abb7ee6ef4ea2e5e645fa1def0a5cd88402df1b46c9ed',
-        'com.google.dagger:dagger-compiler:2.19:dagger-compiler-2.19.jar:27a4b202a2de908182edb261f8c0a264e08e5e4733d7514bc7fbf0d31da5c0fc',
-        'com.google.dagger:dagger-producers:2.19:dagger-producers-2.19.jar:a17663abe0fc38b676026950907d4c5f5e2bf338375415861eaff6e3bdb0b768',
-        'com.google.dagger:dagger-spi:2.19:dagger-spi-2.19.jar:e7a6379d82c841f6aac2866948ad1eed716528707814602842a8d844ce04e2e1',
-        'com.google.dagger:dagger:2.19:dagger-2.19.jar:514b6f1e0727c6572e1d65cb27e4ae668b7aeaeb93a29515182965265b609939',
+        'com.google.dagger:dagger-compiler:2.22.1:dagger-compiler-2.22.1.jar:e5f28302cbe70a79d3620cddebfb8ec0736814f3980ffe1e673bfe3342f507d3',
+        'com.google.dagger:dagger-producers:2.22.1:dagger-producers-2.22.1.jar:f834a0082014213a68ff06a0f048d750178d02196c58b0b15beb367d32b97e35',
+        'com.google.dagger:dagger-spi:2.22.1:dagger-spi-2.22.1.jar:4b0b922793b3bcb91b99fabb75dba77c68afd7ae4c5f0c4fd6ba681f0a291c7d',
+        '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.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.h2database:h2:1.4.192:h2-1.4.192.jar:225b22e9857235c46c93861410b60b8c81c10dc8985f4faf188985ba5445126c',
         'com.madgag.spongycastle:core:1.58.0.0:core-1.58.0.0.jar:199617dd5698c5a9312b898c0a4cec7ce9dd8649d07f65d91629f58229d72728',
         'com.squareup:javapoet:1.11.1:javapoet-1.11.1.jar:9cbf2107be499ec6e95afd36b58e3ca122a24166cdd375732e51267d64058e90',

bramble-java/build.gradle

@@ -19,7 +19,7 @@ dependencies {
 	tor 'org.briarproject:tor:0.3.5.8@zip'
 	tor 'org.briarproject:obfs4proxy:0.0.7@zip'
 
-	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 project(path: ':bramble-core', configuration: 'testOutput')
@@ -28,7 +28,7 @@ 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'
 }
 
 def torBinariesDir = 'src/main/resources'

bramble-java/witness.gradle

@@ -2,15 +2,15 @@ dependencyVerification {
     verify = [
         'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
         'com.google.code.findbugs:jsr305:1.3.9:jsr305-1.3.9.jar:905721a0eea90a81534abb7ee6ef4ea2e5e645fa1def0a5cd88402df1b46c9ed',
-        'com.google.dagger:dagger-compiler:2.19:dagger-compiler-2.19.jar:27a4b202a2de908182edb261f8c0a264e08e5e4733d7514bc7fbf0d31da5c0fc',
-        'com.google.dagger:dagger-producers:2.19:dagger-producers-2.19.jar:a17663abe0fc38b676026950907d4c5f5e2bf338375415861eaff6e3bdb0b768',
-        'com.google.dagger:dagger-spi:2.19:dagger-spi-2.19.jar:e7a6379d82c841f6aac2866948ad1eed716528707814602842a8d844ce04e2e1',
-        'com.google.dagger:dagger:2.19:dagger-2.19.jar:514b6f1e0727c6572e1d65cb27e4ae668b7aeaeb93a29515182965265b609939',
+        'com.google.dagger:dagger-compiler:2.22.1:dagger-compiler-2.22.1.jar:e5f28302cbe70a79d3620cddebfb8ec0736814f3980ffe1e673bfe3342f507d3',
+        'com.google.dagger:dagger-producers:2.22.1:dagger-producers-2.22.1.jar:f834a0082014213a68ff06a0f048d750178d02196c58b0b15beb367d32b97e35',
+        'com.google.dagger:dagger-spi:2.22.1:dagger-spi-2.22.1.jar:4b0b922793b3bcb91b99fabb75dba77c68afd7ae4c5f0c4fd6ba681f0a291c7d',
+        '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.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.squareup:javapoet:1.11.1:javapoet-1.11.1.jar:9cbf2107be499ec6e95afd36b58e3ca122a24166cdd375732e51267d64058e90',
         'javax.annotation:jsr250-api:1.0:jsr250-api-1.0.jar:a1a922d0d9b6d183ed3800dfac01d1e1eb159f0e8c6f94736931c1def54a941f',
         'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',

briar-android/artwork/ic_nearby.svg

@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   width="24"
+   height="24"
+   viewBox="0 0 24 24"
+   version="1.1"
+   id="svg12"
+   sodipodi:docname="nearby.svg"
+   style="fill:none"
+   inkscape:version="0.92.3 (2405546, 2018-03-11)">
+  <metadata
+     id="metadata18">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <defs
+     id="defs16" />
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="1920"
+     inkscape:window-height="1020"
+     id="namedview14"
+     showgrid="false"
+     inkscape:zoom="15.170655"
+     inkscape:cx="9.6488139"
+     inkscape:cy="11.430963"
+     inkscape:window-x="1440"
+     inkscape:window-y="24"
+     inkscape:window-maximized="0"
+     inkscape:current-layer="svg12" />
+  <path
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+     id="path832-3-6"
+     inkscape:connector-curvature="0" />
+</svg>

briar-android/artwork/nickname.svg

@@ -0,0 +1,176 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   width="150"
+   height="178"
+   viewBox="0 0 150 178"
+   fill="none"
+   version="1.1"
+   id="svg129"
+   sodipodi:docname="nickname.svg"
+   inkscape:version="0.92.3 (2405546, 2018-03-11)">
+  <metadata
+     id="metadata133">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="1920"
+     inkscape:window-height="1020"
+     id="namedview131"
+     showgrid="false"
+     inkscape:zoom="3.7500494"
+     inkscape:cx="84.461975"
+     inkscape:cy="96.344913"
+     inkscape:window-x="1440"
+     inkscape:window-y="24"
+     inkscape:window-maximized="0"
+     inkscape:current-layer="svg129" />
+  <path
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+     id="path2"
+     inkscape:connector-curvature="0"
+     style="display:inline;opacity:0.25;fill:url(#paint0_linear)" />
+  <path
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+     inkscape:connector-curvature="0"
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+         stop-opacity="0.25"
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+         stop-opacity="0.1"
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+    </linearGradient>
+    <clipPath
+       id="clip0">
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+         width="150"
+         height="178"
+         fill="white"
+         id="rect124" />
+    </clipPath>
+  </defs>
+</svg>

briar-android/build.gradle

@@ -118,14 +118,15 @@ dependencies {
 	implementation 'com.google.zxing:core:3.3.3'
 	implementation 'uk.co.samuelwall:material-tap-target-prompt:2.14.0'
 	implementation 'com.vanniktech:emoji-google:0.5.1'
-	def glideVersion = '4.8.0'
+	implementation 'com.github.kobakei:MaterialFabSpeedDial:1.2.1' // later versions already use androidx
+	def glideVersion = '4.9.0'
 	implementation("com.github.bumptech.glide:glide:$glideVersion") {
 		exclude group: 'com.android.support'
 		exclude module: 'disklrucache' // when there's no disk cache, we can't accidentally use it
 	}
 	implementation 'com.github.chrisbanes:PhotoView:2.1.4' // later versions already use androidx
 
-	annotationProcessor 'com.google.dagger:dagger-compiler:2.19'
+	annotationProcessor 'com.google.dagger:dagger-compiler:2.22.1'
 	annotationProcessor "com.github.bumptech.glide:compiler:$glideVersion"
 
 	compileOnly 'javax.annotation:jsr250-api:1.0'
@@ -134,7 +135,7 @@ dependencies {
 	testImplementation project(path: ':bramble-core', configuration: 'testOutput')
 	testImplementation 'org.robolectric:robolectric:4.0.1'
 	testImplementation 'org.robolectric:shadows-support-v4:3.3.2'
-	testImplementation 'org.mockito:mockito-core:2.19.0'
+	testImplementation 'org.mockito:mockito-core:2.25.0'
 	testImplementation 'junit:junit:4.12'
 	testImplementation "org.jmock:jmock:2.8.2"
 	testImplementation "org.jmock:jmock-junit4:2.8.2"
@@ -144,7 +145,7 @@ dependencies {
 	androidTestImplementation "com.android.support.test.espresso:espresso-core:$espressoVersion"
 	androidTestImplementation "com.android.support.test.espresso:espresso-contrib:$espressoVersion"
 	androidTestImplementation "com.android.support.test.espresso:espresso-intents:$espressoVersion"
-	androidTestAnnotationProcessor "com.google.dagger:dagger-compiler:2.19"
+	androidTestAnnotationProcessor "com.google.dagger:dagger-compiler:2.22.1"
 	androidTestCompileOnly 'javax.annotation:jsr250-api:1.0'
 	androidTestImplementation 'junit:junit:4.12'
 	androidTestScreenshotImplementation "tools.fastlane:screengrab:1.2.0"

briar-android/src/main/AndroidManifest.xml

@@ -425,5 +425,31 @@
 			android:launchMode="singleTask"
 			android:theme="@style/BriarTheme.NoActionBar"/>
 
+		<activity
+			android:name=".android.contact.add.remote.AddContactActivity"
+			android:label="@string/add_contact_remotely_title_case"
+			android:launchMode="singleTask"
+			android:theme="@style/BriarTheme"
+			android:windowSoftInputMode="stateHidden|adjustResize">
+			<intent-filter>
+				<action android:name="android.intent.action.VIEW"/>
+
+				<category android:name="android.intent.category.DEFAULT"/>
+				<category android:name="android.intent.category.BROWSABLE"/>
+
+				<data android:scheme="briar"/>
+			</intent-filter>
+			<intent-filter>
+				<action android:name="android.intent.action.SEND"/>
+				<category android:name="android.intent.category.DEFAULT"/>
+				<data android:mimeType="text/plain"/>
+			</intent-filter>
+		</activity>
+
+		<activity
+			android:name=".android.contact.add.remote.PendingContactListActivity"
+			android:label="@string/pending_contact_requests"
+			android:theme="@style/BriarTheme"/>
+
 	</application>
 </manifest>

briar-android/src/main/java/org/briarproject/briar/android/AndroidNotificationManagerImpl.java

@@ -42,7 +42,7 @@ import org.briarproject.briar.api.android.AndroidNotificationManager;
 import org.briarproject.briar.api.blog.event.BlogPostAddedEvent;
 import org.briarproject.briar.api.conversation.event.ConversationMessageReceivedEvent;
 import org.briarproject.briar.api.forum.event.ForumPostReceivedEvent;
-import org.briarproject.briar.api.introduction.event.IntroductionSucceededEvent;
+import org.briarproject.bramble.api.contact.event.ContactAddedRemotelyEvent;
 import org.briarproject.briar.api.privategroup.event.GroupMessageAddedEvent;
 
 import java.util.Set;
@@ -99,7 +99,7 @@ class AndroidNotificationManagerImpl implements AndroidNotificationManager,
 	private final Multiset<GroupId> groupCounts = new Multiset<>();
 	private final Multiset<GroupId> forumCounts = new Multiset<>();
 	private final Multiset<GroupId> blogCounts = new Multiset<>();
-	private int introductionTotal = 0;
+	private int contactAddedTotal = 0;
 	private int nextRequestId = 0;
 	private ContactId blockedContact = null;
 	private GroupId blockedGroup = null;
@@ -171,7 +171,7 @@ class AndroidNotificationManagerImpl implements AndroidNotificationManager,
 			clearGroupMessageNotification();
 			clearForumPostNotification();
 			clearBlogPostNotification();
-			clearIntroductionSuccessNotification();
+			clearContactAddedNotification();
 			return null;
 		});
 		try {
@@ -206,9 +206,9 @@ class AndroidNotificationManagerImpl implements AndroidNotificationManager,
 	}
 
 	@UiThread
-	private void clearIntroductionSuccessNotification() {
-		introductionTotal = 0;
-		notificationManager.cancel(INTRODUCTION_SUCCESS_NOTIFICATION_ID);
+	private void clearContactAddedNotification() {
+		contactAddedTotal = 0;
+		notificationManager.cancel(CONTACT_ADDED_NOTIFICATION_ID);
 	}
 
 	@Override
@@ -230,8 +230,8 @@ class AndroidNotificationManagerImpl implements AndroidNotificationManager,
 		} else if (e instanceof BlogPostAddedEvent) {
 			BlogPostAddedEvent b = (BlogPostAddedEvent) e;
 			if (!b.isLocal()) showBlogPostNotification(b.getGroupId());
-		} else if (e instanceof IntroductionSucceededEvent) {
-			showIntroductionNotification();
+		} else if (e instanceof ContactAddedRemotelyEvent) {
+			showContactAddedNotification();
 		}
 	}
 
@@ -563,24 +563,24 @@ class AndroidNotificationManagerImpl implements AndroidNotificationManager,
 	}
 
 	@UiThread
-	private void showIntroductionNotification() {
-		introductionTotal++;
-		updateIntroductionNotification();
+	private void showContactAddedNotification() {
+		contactAddedTotal++;
+		updateContactAddedNotification();
 	}
 
 	@UiThread
-	private void updateIntroductionNotification() {
+	private void updateContactAddedNotification() {
 		BriarNotificationBuilder b =
 				new BriarNotificationBuilder(appContext, CONTACT_CHANNEL_ID);
-		b.setSmallIcon(R.drawable.notification_introduction);
+		b.setSmallIcon(R.drawable.notification_contact_added);
 		b.setColorRes(R.color.briar_primary);
 		b.setContentTitle(appContext.getText(R.string.app_name));
 		b.setContentText(appContext.getResources().getQuantityString(
-				R.plurals.introduction_notification_text, introductionTotal,
-				introductionTotal));
+				R.plurals.contact_added_notification_text, contactAddedTotal,
+				contactAddedTotal));
 		b.setNotificationCategory(CATEGORY_MESSAGE);
 		setAlertProperties(b);
-		setDeleteIntent(b, INTRODUCTION_URI);
+		setDeleteIntent(b, CONTACT_ADDED_URI);
 		// Touching the notification shows the contact list
 		Intent i = new Intent(appContext, NavDrawerActivity.class);
 		i.putExtra(INTENT_CONTACTS, true);
@@ -591,14 +591,13 @@ class AndroidNotificationManagerImpl implements AndroidNotificationManager,
 		t.addNextIntent(i);
 		b.setContentIntent(t.getPendingIntent(nextRequestId++, 0));
 
-		notificationManager.notify(INTRODUCTION_SUCCESS_NOTIFICATION_ID,
+		notificationManager.notify(CONTACT_ADDED_NOTIFICATION_ID,
 				b.build());
 	}
 
 	@Override
-	public void clearAllIntroductionNotifications() {
-		androidExecutor.runOnUiThread(
-				this::clearIntroductionSuccessNotification);
+	public void clearAllContactAddedNotifications() {
+		androidExecutor.runOnUiThread(this::clearContactAddedNotification);
 	}
 
 	@Override

briar-android/src/main/java/org/briarproject/briar/android/AppModule.java

@@ -226,7 +226,7 @@ public class AppModule {
 	@Singleton
 	RecentEmoji provideRecentEmoji(LifecycleManager lifecycleManager,
 			RecentEmojiImpl recentEmoji) {
-		lifecycleManager.registerClient(recentEmoji);
+		lifecycleManager.registerOpenDatabaseHook(recentEmoji);
 		return recentEmoji;
 	}
 }

briar-android/src/main/java/org/briarproject/briar/android/NotificationCleanupService.java

@@ -12,7 +12,7 @@ import static org.briarproject.briar.api.android.AndroidNotificationManager.BLOG
 import static org.briarproject.briar.api.android.AndroidNotificationManager.CONTACT_URI;
 import static org.briarproject.briar.api.android.AndroidNotificationManager.FORUM_URI;
 import static org.briarproject.briar.api.android.AndroidNotificationManager.GROUP_URI;
-import static org.briarproject.briar.api.android.AndroidNotificationManager.INTRODUCTION_URI;
+import static org.briarproject.briar.api.android.AndroidNotificationManager.CONTACT_ADDED_URI;
 
 public class NotificationCleanupService extends IntentService {
 
@@ -46,8 +46,8 @@ public class NotificationCleanupService extends IntentService {
 			notificationManager.clearAllForumPostNotifications();
 		} else if (uri.equals(BLOG_URI)) {
 			notificationManager.clearAllBlogPostNotifications();
-		} else if (uri.equals(INTRODUCTION_URI)) {
-			notificationManager.clearAllIntroductionNotifications();
+		} else if (uri.equals(CONTACT_ADDED_URI)) {
+			notificationManager.clearAllContactAddedNotifications();
 		}
 	}
 }

briar-android/src/main/java/org/briarproject/briar/android/RecentEmojiImpl.java

@@ -8,11 +8,11 @@ import com.vanniktech.emoji.emoji.Emoji;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager.OpenDatabaseHook;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.settings.Settings;
 import org.briarproject.bramble.api.settings.SettingsManager;
-import org.briarproject.bramble.api.sync.Client;
 import org.briarproject.bramble.api.system.AndroidExecutor;
 import org.briarproject.bramble.util.StringUtils;
 
@@ -30,7 +30,7 @@ import static org.briarproject.briar.android.settings.SettingsFragment.SETTINGS_
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-class RecentEmojiImpl implements RecentEmoji, Client {
+class RecentEmojiImpl implements RecentEmoji, OpenDatabaseHook {
 
 	private static final Logger LOG =
 			Logger.getLogger(RecentEmojiImpl.class.getName());
@@ -72,7 +72,7 @@ class RecentEmojiImpl implements RecentEmoji, Client {
 	}
 
 	@Override
-	public void createLocalState(Transaction txn) throws DbException {
+	public void onDatabaseOpened(Transaction txn) throws DbException {
 		Settings settings =
 				settingsManager.getSettings(txn, SETTINGS_NAMESPACE);
 		String serialized = settings.get(EMOJI_LRU_PREFERENCE);

briar-android/src/main/java/org/briarproject/briar/android/TestingConstants.java

@@ -36,4 +36,9 @@ public interface TestingConstants {
 	 */
 	boolean FEATURE_FLAG_IMAGE_ATTACHMENTS = IS_DEBUG_BUILD;
 
+	/**
+	 * Feature flag for enabling adding contacts at a distance.
+	 */
+	boolean FEATURE_FLAG_REMOTE_CONTACTS = IS_DEBUG_BUILD;
+
 }

briar-android/src/main/java/org/briarproject/briar/android/activity/ActivityComponent.java

@@ -15,8 +15,12 @@ import org.briarproject.briar.android.blog.ReblogFragment;
 import org.briarproject.briar.android.blog.RssFeedImportActivity;
 import org.briarproject.briar.android.blog.RssFeedManageActivity;
 import org.briarproject.briar.android.blog.WriteBlogPostActivity;
+import org.briarproject.briar.android.contact.add.remote.AddContactActivity;
+import org.briarproject.briar.android.contact.add.remote.LinkExchangeFragment;
 import org.briarproject.briar.android.contact.ContactListFragment;
 import org.briarproject.briar.android.contact.ContactModule;
+import org.briarproject.briar.android.contact.add.remote.NicknameFragment;
+import org.briarproject.briar.android.contact.add.remote.PendingContactListActivity;
 import org.briarproject.briar.android.conversation.AliasDialogFragment;
 import org.briarproject.briar.android.conversation.ConversationActivity;
 import org.briarproject.briar.android.conversation.ImageActivity;
@@ -168,6 +172,10 @@ public interface ActivityComponent {
 
 	void inject(UnlockActivity activity);
 
+	void inject(AddContactActivity activity);
+
+	void inject(PendingContactListActivity activity);
+
 	// Fragments
 	void inject(AuthorNameFragment fragment);
 
@@ -191,6 +199,10 @@ public interface ActivityComponent {
 
 	void inject(KeyAgreementFragment fragment);
 
+	void inject(LinkExchangeFragment fragment);
+
+	void inject(NicknameFragment fragment);
+
 	void inject(ContactChooserFragment fragment);
 
 	void inject(ShareForumFragment fragment);

briar-android/src/main/java/org/briarproject/briar/android/blog/BlogFragment.java

@@ -5,8 +5,6 @@ import android.content.Intent;
 import android.os.Bundle;
 import android.os.Parcelable;
 import android.support.annotation.UiThread;
-import android.support.design.widget.Snackbar;
-import android.support.v4.content.ContextCompat;
 import android.support.v7.app.ActionBar;
 import android.support.v7.app.AlertDialog;
 import android.support.v7.widget.LinearLayoutManager;
@@ -34,6 +32,7 @@ import org.briarproject.briar.android.controller.handler.UiResultExceptionHandle
 import org.briarproject.briar.android.fragment.BaseFragment;
 import org.briarproject.briar.android.sharing.BlogSharingStatusActivity;
 import org.briarproject.briar.android.sharing.ShareBlogActivity;
+import org.briarproject.briar.android.util.BriarSnackbarBuilder;
 import org.briarproject.briar.android.view.BriarRecyclerView;
 import org.briarproject.briar.api.blog.BlogPostHeader;
 
@@ -44,6 +43,7 @@ import javax.inject.Inject;
 
 import static android.app.Activity.RESULT_OK;
 import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
+import static android.support.design.widget.Snackbar.LENGTH_LONG;
 import static android.widget.Toast.LENGTH_SHORT;
 import static java.util.Objects.requireNonNull;
 import static org.briarproject.briar.android.activity.BriarActivity.GROUP_ID;
@@ -356,17 +356,12 @@ public class BlogFragment extends BaseFragment
 	}
 
 	private void displaySnackbar(int stringId, boolean scroll) {
-		Snackbar snackbar =
-				Snackbar.make(list, stringId, Snackbar.LENGTH_LONG);
-		snackbar.getView().setBackgroundResource(R.color.briar_primary);
+		BriarSnackbarBuilder sb = new BriarSnackbarBuilder();
 		if (scroll) {
-			View.OnClickListener onClick = v -> list.smoothScrollToPosition(0);
-			snackbar.setActionTextColor(ContextCompat
-					.getColor(getContext(),
-							R.color.briar_button_text_positive));
-			snackbar.setAction(R.string.blogs_blog_post_scroll_to, onClick);
+			sb.setAction(R.string.blogs_blog_post_scroll_to,
+					v -> list.smoothScrollToPosition(0));
 		}
-		snackbar.show();
+		sb.make(list, stringId, LENGTH_LONG).show();
 	}
 
 	private void showDeleteDialog() {

briar-android/src/main/java/org/briarproject/briar/android/blog/FeedFragment.java

@@ -4,15 +4,12 @@ import android.content.Intent;
 import android.os.Bundle;
 import android.os.Parcelable;
 import android.support.annotation.UiThread;
-import android.support.design.widget.Snackbar;
-import android.support.v4.content.ContextCompat;
 import android.support.v7.widget.LinearLayoutManager;
 import android.view.LayoutInflater;
 import android.view.Menu;
 import android.view.MenuInflater;
 import android.view.MenuItem;
 import android.view.View;
-import android.view.View.OnClickListener;
 import android.view.ViewGroup;
 
 import org.briarproject.bramble.api.db.DbException;
@@ -23,6 +20,7 @@ import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.blog.FeedController.FeedListener;
 import org.briarproject.briar.android.controller.handler.UiResultExceptionHandler;
 import org.briarproject.briar.android.fragment.BaseFragment;
+import org.briarproject.briar.android.util.BriarSnackbarBuilder;
 import org.briarproject.briar.android.view.BriarRecyclerView;
 import org.briarproject.briar.api.blog.Blog;
 import org.briarproject.briar.api.blog.BlogPostHeader;
@@ -270,16 +268,12 @@ public class FeedFragment extends BaseFragment implements
 		int count = adapter.getItemCount();
 		boolean scroll = count > (lastVisible - firstVisible + 1);
 
-		Snackbar s = Snackbar.make(list, stringRes, LENGTH_LONG);
-		s.getView().setBackgroundResource(R.color.briar_primary);
+		BriarSnackbarBuilder sb = new BriarSnackbarBuilder();
 		if (scroll) {
-			OnClickListener onClick = v -> list.smoothScrollToPosition(0);
-			s.setActionTextColor(ContextCompat
-					.getColor(getContext(),
-							R.color.briar_button_text_positive));
-			s.setAction(R.string.blogs_blog_post_scroll_to, onClick);
+			sb.setAction(R.string.blogs_blog_post_scroll_to,
+					v -> list.smoothScrollToPosition(0));
 		}
-		s.show();
+		sb.make(list, stringRes, LENGTH_LONG).show();
 	}
 
 	@Override

briar-android/src/main/java/org/briarproject/briar/android/contact/ContactListFragment.java

@@ -3,22 +3,25 @@ package org.briarproject.briar.android.contact;
 import android.content.Intent;
 import android.os.Bundle;
 import android.support.annotation.UiThread;
+import android.support.design.widget.FloatingActionButton;
+import android.support.design.widget.Snackbar;
 import android.support.v4.app.ActivityCompat;
 import android.support.v4.app.ActivityOptionsCompat;
 import android.support.v4.util.Pair;
 import android.support.v7.widget.LinearLayoutManager;
 import android.view.LayoutInflater;
-import android.view.Menu;
-import android.view.MenuInflater;
-import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
+import android.widget.TextView;
 
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
 import org.briarproject.bramble.api.contact.event.ContactAddedEvent;
+import org.briarproject.bramble.api.contact.event.ContactAddedRemotelyEvent;
 import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
+import org.briarproject.bramble.api.contact.event.PendingContactRemovedEvent;
+import org.briarproject.bramble.api.contact.event.PendingContactStateChangedEvent;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.NoSuchContactException;
 import org.briarproject.bramble.api.event.Event;
@@ -32,9 +35,12 @@ import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
+import org.briarproject.briar.android.contact.add.remote.AddContactActivity;
+import org.briarproject.briar.android.contact.add.remote.PendingContactListActivity;
 import org.briarproject.briar.android.conversation.ConversationActivity;
 import org.briarproject.briar.android.fragment.BaseFragment;
 import org.briarproject.briar.android.keyagreement.ContactExchangeActivity;
+import org.briarproject.briar.android.util.BriarSnackbarBuilder;
 import org.briarproject.briar.android.view.BriarRecyclerView;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
 import org.briarproject.briar.api.client.MessageTracker.GroupCount;
@@ -49,20 +55,28 @@ import java.util.logging.Logger;
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 
+import io.github.kobakei.materialfabspeeddial.FabSpeedDial;
+import io.github.kobakei.materialfabspeeddial.FabSpeedDial.OnMenuItemClickListener;
+import io.github.kobakei.materialfabspeeddial.FabSpeedDialMenu;
+
 import static android.os.Build.VERSION.SDK_INT;
+import static android.support.design.widget.Snackbar.LENGTH_INDEFINITE;
 import static android.support.v4.app.ActivityOptionsCompat.makeSceneTransitionAnimation;
 import static android.support.v4.view.ViewCompat.getTransitionName;
 import static java.util.Objects.requireNonNull;
 import static java.util.logging.Level.WARNING;
+import static org.briarproject.bramble.api.contact.PendingContactState.WAITING_FOR_CONNECTION;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.LogUtils.now;
+import static org.briarproject.briar.android.TestingConstants.FEATURE_FLAG_REMOTE_CONTACTS;
 import static org.briarproject.briar.android.conversation.ConversationActivity.CONTACT_ID;
 import static org.briarproject.briar.android.util.UiUtils.isSamsung7;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-public class ContactListFragment extends BaseFragment implements EventListener {
+public class ContactListFragment extends BaseFragment implements EventListener,
+		OnMenuItemClickListener {
 
 	public static final String TAG = ContactListFragment.class.getName();
 	private static final Logger LOG = Logger.getLogger(TAG);
@@ -76,6 +90,7 @@ public class ContactListFragment extends BaseFragment implements EventListener {
 
 	private ContactListAdapter adapter;
 	private BriarRecyclerView list;
+	private Snackbar snackbar;
 
 	// Fields that are accessed from background threads must be volatile
 	@Inject
@@ -107,7 +122,23 @@ public class ContactListFragment extends BaseFragment implements EventListener {
 			@Nullable Bundle savedInstanceState) {
 		requireNonNull(getActivity()).setTitle(R.string.contact_list_button);
 
-		View contentView = inflater.inflate(R.layout.list, container, false);
+		View contentView = inflater.inflate(R.layout.fragment_contact_list,
+				container, false);
+
+		FabSpeedDial speedDial = contentView.findViewById(R.id.speedDial);
+		if (FEATURE_FLAG_REMOTE_CONTACTS) {
+			speedDial.addOnMenuItemClickListener(this);
+		} else {
+			speedDial.setMenu(new FabSpeedDialMenu(contentView.getContext()));
+			speedDial.addOnStateChangeListener(open -> {
+				if (open) {
+					Intent intent = new Intent(getContext(),
+							ContactExchangeActivity.class);
+					startActivity(intent);
+					speedDial.closeMenu();
+				}
+			});
+		}
 
 		OnContactClickListener<ContactListItem> onContactClickListener =
 				(view, item) -> {
@@ -146,26 +177,28 @@ public class ContactListFragment extends BaseFragment implements EventListener {
 		list.setEmptyText(getString(R.string.no_contacts));
 		list.setEmptyAction(getString(R.string.no_contacts_action));
 
+		snackbar = new BriarSnackbarBuilder()
+				.setAction(R.string.show, v ->
+						startActivity(new Intent(getContext(),
+								PendingContactListActivity.class)))
+				.make(contentView, R.string.pending_contact_requests_snackbar,
+						LENGTH_INDEFINITE);
+
 		return contentView;
 	}
 
 	@Override
-	public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
-		inflater.inflate(R.menu.contact_list_actions, menu);
-		super.onCreateOptionsMenu(menu, inflater);
-	}
-
-	@Override
-	public boolean onOptionsItemSelected(MenuItem item) {
-		// Handle presses on the action bar items
-		switch (item.getItemId()) {
-			case R.id.action_add_contact:
+	public void onMenuItemClick(FloatingActionButton fab, @Nullable TextView v,
+			int itemId) {
+		switch (itemId) {
+			case R.id.action_add_contact_nearby:
 				Intent intent =
 						new Intent(getContext(), ContactExchangeActivity.class);
 				startActivity(intent);
-				return true;
-			default:
-				return super.onOptionsItemSelected(item);
+				return;
+			case R.id.action_add_contact_remotely:
+				startActivity(
+						new Intent(getContext(), AddContactActivity.class));
 		}
 	}
 
@@ -174,11 +207,26 @@ public class ContactListFragment extends BaseFragment implements EventListener {
 		super.onStart();
 		eventBus.addListener(this);
 		notificationManager.clearAllContactNotifications();
-		notificationManager.clearAllIntroductionNotifications();
+		notificationManager.clearAllContactAddedNotifications();
 		loadContacts();
+		checkForPendingContacts();
 		list.startPeriodicUpdate();
 	}
 
+	private void checkForPendingContacts() {
+		listener.runOnDbThread(() -> {
+			try {
+				if (contactManager.getPendingContacts().isEmpty()) {
+					runOnUiThreadUnlessDestroyed(() -> snackbar.dismiss());
+				} else {
+					runOnUiThreadUnlessDestroyed(() -> snackbar.show());
+				}
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
 	@Override
 	public void onStop() {
 		super.onStop();
@@ -245,6 +293,16 @@ public class ContactListFragment extends BaseFragment implements EventListener {
 					(ConversationMessageReceivedEvent) e;
 			ConversationMessageHeader h = p.getMessageHeader();
 			updateItem(p.getContactId(), h);
+		} else if (e instanceof PendingContactStateChangedEvent) {
+			PendingContactStateChangedEvent pe =
+					(PendingContactStateChangedEvent) e;
+			// only re-check pending contacts for initial state
+			if (pe.getPendingContactState() == WAITING_FOR_CONNECTION) {
+				checkForPendingContacts();
+			}
+		} else if (e instanceof PendingContactRemovedEvent ||
+				e instanceof ContactAddedRemotelyEvent) {
+			checkForPendingContacts();
 		}
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/contact/add/remote/AddContactActivity.java

@@ -0,0 +1,105 @@
+package org.briarproject.briar.android.contact.add.remote;
+
+import android.arch.lifecycle.ViewModelProvider;
+import android.arch.lifecycle.ViewModelProviders;
+import android.content.Intent;
+import android.os.Bundle;
+import android.support.v7.app.ActionBar;
+import android.view.MenuItem;
+import android.widget.Toast;
+
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.activity.BriarActivity;
+import org.briarproject.briar.android.fragment.BaseFragment.BaseFragmentListener;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+
+import static android.content.Intent.ACTION_SEND;
+import static android.content.Intent.ACTION_VIEW;
+import static android.content.Intent.EXTRA_TEXT;
+import static android.widget.Toast.LENGTH_LONG;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public class AddContactActivity extends BriarActivity implements
+		BaseFragmentListener {
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+	private AddContactViewModel viewModel;
+
+	@Override
+	public void injectActivity(ActivityComponent component) {
+		component.inject(this);
+	}
+
+	@Override
+	public void onCreate(@Nullable Bundle state) {
+		super.onCreate(state);
+		setContentView(R.layout.activity_fragment_container);
+
+		ActionBar ab = getSupportActionBar();
+		if (ab != null) {
+			ab.setDisplayHomeAsUpEnabled(true);
+		}
+
+		viewModel = ViewModelProviders.of(this, viewModelFactory)
+				.get(AddContactViewModel.class);
+		viewModel.getRemoteLinkEntered().observeEvent(this, entered -> {
+			if (entered) {
+				NicknameFragment f = new NicknameFragment();
+				showNextFragment(f);
+			}
+		});
+
+		Intent i = getIntent();
+		if (i != null) {
+			onNewIntent(i);
+			setIntent(null);  // don't keep the intent for configuration changes
+		}
+
+		if (state == null) {
+			showInitialFragment(new LinkExchangeFragment());
+		}
+	}
+
+	@Override
+	protected void onNewIntent(Intent i) {
+		super.onNewIntent(i);
+		String action = i.getAction();
+		if (ACTION_SEND.equals(action) || ACTION_VIEW.equals(action)) {
+			String text = i.getStringExtra(EXTRA_TEXT);
+			String uri = i.getDataString();
+			if (text != null) handleIncomingLink(text);
+			else if (uri != null) handleIncomingLink(uri);
+		}
+	}
+
+	private void handleIncomingLink(String link) {
+		if (link.equals(viewModel.getHandshakeLink().getValue())) {
+			Toast.makeText(this, R.string.intent_own_link, LENGTH_LONG)
+					.show();
+		} else if (viewModel.isValidRemoteContactLink(link)) {
+			viewModel.setRemoteHandshakeLink(link);
+		} else {
+			Toast.makeText(this, R.string.invalid_link, LENGTH_LONG)
+					.show();
+		}
+	}
+
+	@Override
+	public boolean onOptionsItemSelected(MenuItem item) {
+		switch (item.getItemId()) {
+			case android.R.id.home:
+				onBackPressed();
+				return true;
+			default:
+				return super.onOptionsItemSelected(item);
+		}
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/contact/add/remote/AddContactViewModel.java

@@ -0,0 +1,112 @@
+package org.briarproject.briar.android.contact.add.remote;
+
+import android.app.Application;
+import android.arch.lifecycle.AndroidViewModel;
+import android.arch.lifecycle.LiveData;
+import android.arch.lifecycle.MutableLiveData;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.contact.ContactManager;
+import org.briarproject.bramble.api.db.DatabaseExecutor;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.android.viewmodel.LiveEvent;
+import org.briarproject.briar.android.viewmodel.MutableLiveEvent;
+
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.contact.HandshakeLinkConstants.LINK_REGEX;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+@NotNullByDefault
+public class AddContactViewModel extends AndroidViewModel {
+
+	private final static Logger LOG =
+			getLogger(AddContactViewModel.class.getName());
+
+	private final ContactManager contactManager;
+	@DatabaseExecutor
+	private final Executor dbExecutor;
+
+	private final MutableLiveData<String> handshakeLink =
+			new MutableLiveData<>();
+	private final MutableLiveEvent<Boolean> remoteLinkEntered =
+			new MutableLiveEvent<>();
+	private final MutableLiveData<Boolean> addContactResult =
+			new MutableLiveData<>();
+	@Nullable
+	private String remoteHandshakeLink;
+
+	@Inject
+	public AddContactViewModel(@NonNull Application application,
+			ContactManager contactManager,
+			@DatabaseExecutor Executor dbExecutor) {
+		super(application);
+		this.contactManager = contactManager;
+		this.dbExecutor = dbExecutor;
+		loadHandshakeLink();
+	}
+
+	private void loadHandshakeLink() {
+		dbExecutor.execute(() -> {
+			try {
+				handshakeLink.postValue(contactManager.getHandshakeLink());
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+				// the UI should stay disable in this case,
+				// leaving the user unable to proceed
+			}
+		});
+	}
+
+	LiveData<String> getHandshakeLink() {
+		return handshakeLink;
+	}
+
+	@Nullable
+	String getRemoteHandshakeLink() {
+		return remoteHandshakeLink;
+	}
+
+	void setRemoteHandshakeLink(String link) {
+		remoteHandshakeLink = link;
+	}
+
+	boolean isValidRemoteContactLink(@Nullable CharSequence link) {
+		return link != null && LINK_REGEX.matcher(link).find();
+	}
+
+	LiveEvent<Boolean> getRemoteLinkEntered() {
+		return remoteLinkEntered;
+	}
+
+	void onRemoteLinkEntered() {
+		if (remoteHandshakeLink == null) throw new IllegalStateException();
+		remoteLinkEntered.setEvent(true);
+	}
+
+	void addContact(String nickname) {
+		if (remoteHandshakeLink == null) throw new IllegalStateException();
+		dbExecutor.execute(() -> {
+			try {
+				contactManager.addPendingContact(remoteHandshakeLink, nickname);
+				addContactResult.postValue(true);
+			} catch (DbException | FormatException e) {
+				logException(LOG, WARNING, e);
+				addContactResult.postValue(false);
+			}
+		});
+	}
+
+	LiveData<Boolean> getAddContactResult() {
+		return addContactResult;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/contact/add/remote/LinkExchangeFragment.java

@@ -0,0 +1,164 @@
+package org.briarproject.briar.android.contact.add.remote;
+
+import android.arch.lifecycle.ViewModelProvider;
+import android.arch.lifecycle.ViewModelProviders;
+import android.content.ClipData;
+import android.content.ClipboardManager;
+import android.os.Bundle;
+import android.support.design.widget.TextInputEditText;
+import android.support.design.widget.TextInputLayout;
+import android.support.v4.app.ShareCompat.IntentBuilder;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Button;
+import android.widget.TextView;
+import android.widget.Toast;
+
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.fragment.BaseFragment;
+
+import java.util.regex.Matcher;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+
+import static android.content.Context.CLIPBOARD_SERVICE;
+import static android.widget.Toast.LENGTH_SHORT;
+import static java.util.Objects.requireNonNull;
+import static org.briarproject.bramble.api.contact.HandshakeLinkConstants.LINK_REGEX;
+import static org.briarproject.briar.android.util.UiUtils.observeOnce;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public class LinkExchangeFragment extends BaseFragment {
+
+	private static final String TAG = LinkExchangeFragment.class.getName();
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private AddContactViewModel viewModel;
+
+	private ClipboardManager clipboard;
+	private TextInputLayout linkInputLayout;
+	private TextInputEditText linkInput;
+
+	@Override
+	public String getUniqueTag() {
+		return TAG;
+	}
+
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+	}
+
+	@Nullable
+	@Override
+	public View onCreateView(LayoutInflater inflater,
+			@Nullable ViewGroup container,
+			@Nullable Bundle savedInstanceState) {
+		if (getActivity() == null || getContext() == null) return null;
+
+		viewModel = ViewModelProviders.of(getActivity(), viewModelFactory)
+				.get(AddContactViewModel.class);
+
+		View v = inflater.inflate(R.layout.fragment_link_exchange,
+				container, false);
+
+		linkInputLayout = v.findViewById(R.id.linkInputLayout);
+		linkInput = v.findViewById(R.id.linkInput);
+		if (viewModel.getRemoteHandshakeLink() != null) {
+			// This can happen if the link was set via an incoming Intent
+			linkInput.setText(viewModel.getRemoteHandshakeLink());
+		}
+
+		clipboard = (ClipboardManager) requireNonNull(
+				getContext().getSystemService(CLIPBOARD_SERVICE));
+
+		Button pasteButton = v.findViewById(R.id.pasteButton);
+		pasteButton.setOnClickListener(view -> {
+			ClipData clipData = clipboard.getPrimaryClip();
+			if (clipData != null && clipData.getItemCount() > 0)
+				linkInput.setText(clipData.getItemAt(0).getText());
+		});
+
+		observeOnce(viewModel.getHandshakeLink(), this,
+				this::onHandshakeLinkLoaded);
+
+		return v;
+	}
+
+	private void onHandshakeLinkLoaded(String link) {
+		View v = requireNonNull(getView());
+
+		TextView linkView = v.findViewById(R.id.linkView);
+		linkView.setText(link);
+
+		Button copyButton = v.findViewById(R.id.copyButton);
+		ClipData clip = ClipData.newPlainText(
+				getString(R.string.link_clip_label), link);
+		copyButton.setOnClickListener(view -> {
+			clipboard.setPrimaryClip(clip);
+			Toast.makeText(getContext(), R.string.link_copied_toast,
+					LENGTH_SHORT).show();
+		});
+		copyButton.setEnabled(true);
+
+		Button shareButton = v.findViewById(R.id.shareButton);
+		shareButton.setOnClickListener(view ->
+				IntentBuilder.from(requireActivity())
+						.setText(link)
+						.setType("text/plain")
+						.startChooser());
+		shareButton.setEnabled(true);
+
+		Button continueButton = v.findViewById(R.id.addButton);
+		continueButton.setOnClickListener(view -> onContinueButtonClicked());
+		continueButton.setEnabled(true);
+	}
+
+	/**
+	 * Requires {@link AddContactViewModel#getHandshakeLink()} to be loaded.
+	 */
+	@Nullable
+	private String getRemoteHandshakeLinkOrNull() {
+		CharSequence link = linkInput.getText();
+		if (link == null || link.length() == 0) {
+			linkInputLayout.setError(getString(R.string.missing_link));
+			linkInput.requestFocus();
+			return null;
+		}
+
+		Matcher matcher = LINK_REGEX.matcher(link);
+		if (matcher.find()) {
+			String linkWithoutSchema = matcher.group(2);
+			// Check also if this is our own link. This was loaded already,
+			// because it enables the Continue button which is the only caller.
+			if (("briar://" + linkWithoutSchema)
+					.equals(viewModel.getHandshakeLink().getValue())) {
+				linkInputLayout.setError(getString(R.string.own_link_error));
+				linkInput.requestFocus();
+				return null;
+			}
+			linkInputLayout.setError(null);
+			return linkWithoutSchema;
+		}
+		linkInputLayout.setError(getString(R.string.invalid_link));
+		linkInput.requestFocus();
+		return null;
+	}
+
+	private void onContinueButtonClicked() {
+		String link = getRemoteHandshakeLinkOrNull();
+		if (link == null) return;  // invalid link
+
+		viewModel.setRemoteHandshakeLink(link);
+		viewModel.onRemoteLinkEntered();
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/contact/add/remote/NicknameFragment.java

@@ -0,0 +1,121 @@
+package org.briarproject.briar.android.contact.add.remote;
+
+import android.arch.lifecycle.ViewModelProvider;
+import android.arch.lifecycle.ViewModelProviders;
+import android.content.Intent;
+import android.os.Bundle;
+import android.support.design.widget.TextInputEditText;
+import android.support.design.widget.TextInputLayout;
+import android.text.Editable;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Button;
+import android.widget.ProgressBar;
+import android.widget.Toast;
+
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.fragment.BaseFragment;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+
+import static android.view.View.INVISIBLE;
+import static android.view.View.VISIBLE;
+import static android.widget.Toast.LENGTH_LONG;
+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
+import static org.briarproject.bramble.util.StringUtils.utf8IsTooLong;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public class NicknameFragment extends BaseFragment {
+
+	private static final String TAG = NicknameFragment.class.getName();
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private AddContactViewModel viewModel;
+
+	private TextInputLayout contactNameLayout;
+	private TextInputEditText contactNameInput;
+	private Button addButton;
+	private ProgressBar progressBar;
+
+	@Override
+	public String getUniqueTag() {
+		return TAG;
+	}
+
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+	}
+
+	@Nullable
+	@Override
+	public View onCreateView(LayoutInflater inflater,
+			@Nullable ViewGroup container,
+			@Nullable Bundle savedInstanceState) {
+		if (getActivity() == null || getContext() == null) return null;
+
+		View v = inflater.inflate(R.layout.fragment_nickname,
+				container, false);
+
+		viewModel = ViewModelProviders.of(getActivity(), viewModelFactory)
+				.get(AddContactViewModel.class);
+
+		contactNameLayout = v.findViewById(R.id.contactNameLayout);
+		contactNameInput = v.findViewById(R.id.contactNameInput);
+
+		addButton = v.findViewById(R.id.addButton);
+		addButton.setOnClickListener(view -> onAddButtonClicked());
+
+		progressBar = v.findViewById(R.id.progressBar);
+
+		return v;
+	}
+
+	@Nullable
+	private String getNicknameOrNull() {
+		Editable name = contactNameInput.getText();
+		if (name == null || name.toString().trim().length() == 0) {
+			contactNameLayout.setError(getString(R.string.nickname_missing));
+			contactNameInput.requestFocus();
+			return null;
+		}
+		if (utf8IsTooLong(name.toString(), MAX_AUTHOR_NAME_LENGTH)) {
+			contactNameLayout.setError(getString(R.string.name_too_long));
+			contactNameInput.requestFocus();
+			return null;
+		}
+		contactNameLayout.setError(null);
+		return name.toString().trim();
+	}
+
+	private void onAddButtonClicked() {
+		String name = getNicknameOrNull();
+		if (name == null) return;  // invalid nickname
+
+		addButton.setVisibility(INVISIBLE);
+		progressBar.setVisibility(VISIBLE);
+
+		viewModel.getAddContactResult().observe(this, success -> {
+			if (success == null) return;
+			if (success) {
+				Intent intent = new Intent(getActivity(),
+						PendingContactListActivity.class);
+				startActivity(intent);
+			} else {
+				Toast.makeText(getContext(), R.string.adding_contact_error,
+						LENGTH_LONG).show();
+			}
+			finish();
+		});
+		viewModel.addContact(name);
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/contact/add/remote/PendingContactListActivity.java

@@ -0,0 +1,105 @@
+package org.briarproject.briar.android.contact.add.remote;
+
+import android.arch.lifecycle.ViewModelProvider;
+import android.arch.lifecycle.ViewModelProviders;
+import android.os.Bundle;
+import android.support.v7.app.ActionBar;
+import android.support.v7.widget.LinearLayoutManager;
+import android.view.MenuItem;
+
+import org.briarproject.bramble.api.contact.PendingContact;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.activity.BriarActivity;
+import org.briarproject.briar.android.view.BriarRecyclerView;
+
+import java.util.Collection;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public class PendingContactListActivity extends BriarActivity
+		implements PendingContactListener {
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private PendingContactListViewModel viewModel;
+	private PendingContactListAdapter adapter;
+	private BriarRecyclerView list;
+
+	@Override
+	public void injectActivity(ActivityComponent component) {
+		component.inject(this);
+	}
+
+	@Override
+	public void onCreate(@Nullable Bundle state) {
+		super.onCreate(state);
+
+		setContentView(R.layout.list);
+
+		ActionBar ab = getSupportActionBar();
+		if (ab != null) {
+			ab.setDisplayHomeAsUpEnabled(true);
+		}
+
+		viewModel = ViewModelProviders.of(this, viewModelFactory)
+				.get(PendingContactListViewModel.class);
+		viewModel.getPendingContacts()
+				.observe(this, this::onPendingContactsChanged);
+
+		adapter = new PendingContactListAdapter(this, this, PendingContact.class);
+		list = findViewById(R.id.list);
+		list.setEmptyText(R.string.no_pending_contacts);
+		list.setLayoutManager(new LinearLayoutManager(this));
+		list.setAdapter(adapter);
+		list.showProgressBar();
+	}
+
+	@Override
+	public void onStart() {
+		super.onStart();
+		list.startPeriodicUpdate();
+	}
+
+	@Override
+	protected void onStop() {
+		super.onStop();
+		list.stopPeriodicUpdate();
+	}
+
+	@Override
+	public boolean onOptionsItemSelected(MenuItem item) {
+		switch (item.getItemId()) {
+			case android.R.id.home:
+				onBackPressed();
+				return true;
+			default:
+				return super.onOptionsItemSelected(item);
+		}
+	}
+
+	@Override
+	public void onFailedPendingContactRemoved(PendingContact pendingContact) {
+		viewModel.removePendingContact(pendingContact.getId());
+	}
+
+	private void onPendingContactsChanged(Collection<PendingContact> contacts) {
+		if (contacts.isEmpty()) {
+			if (adapter.isEmpty()) {
+				list.showData();  // hides progress bar, shows empty text
+			} else {
+				// all previous contacts have been removed, so we can finish
+				supportFinishAfterTransition();
+			}
+		} else {
+			adapter.setItems(contacts);
+		}
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/contact/add/remote/PendingContactListAdapter.java

@@ -0,0 +1,59 @@
+package org.briarproject.briar.android.contact.add.remote;
+
+import android.content.Context;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+
+import org.briarproject.bramble.api.contact.PendingContact;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.util.BriarAdapter;
+
+@NotNullByDefault
+class PendingContactListAdapter extends
+		BriarAdapter<PendingContact, PendingContactViewHolder> {
+
+	private final PendingContactListener listener;
+
+	PendingContactListAdapter(Context ctx, PendingContactListener listener,
+			Class<PendingContact> c) {
+		super(ctx, c);
+		this.listener = listener;
+	}
+
+	@Override
+	public PendingContactViewHolder onCreateViewHolder(ViewGroup viewGroup,
+			int i) {
+		View v = LayoutInflater.from(viewGroup.getContext()).inflate(
+				R.layout.list_item_pending_contact, viewGroup, false);
+		return new PendingContactViewHolder(v, listener);
+	}
+
+	@Override
+	public void onBindViewHolder(
+			PendingContactViewHolder pendingContactViewHolder, int i) {
+		pendingContactViewHolder.bind(items.get(i));
+	}
+
+	@Override
+	public int compare(PendingContact item1, PendingContact item2) {
+		return (int) (item1.getTimestamp() - item2.getTimestamp());
+	}
+
+	@Override
+	public boolean areContentsTheSame(PendingContact item1,
+			PendingContact item2) {
+		return item1.getId().equals(item2.getId()) &&
+				item1.getAlias().equals(item2.getAlias()) &&
+				item1.getTimestamp() == item2.getTimestamp() &&
+				item1.getState() == item2.getState();
+	}
+
+	@Override
+	public boolean areItemsTheSame(PendingContact item1,
+			PendingContact item2) {
+		return item1.getId().equals(item2.getId());
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/contact/add/remote/PendingContactListViewModel.java

@@ -0,0 +1,97 @@
+package org.briarproject.briar.android.contact.add.remote;
+
+import android.app.Application;
+import android.arch.lifecycle.AndroidViewModel;
+import android.arch.lifecycle.LiveData;
+import android.arch.lifecycle.MutableLiveData;
+
+import org.briarproject.bramble.api.contact.ContactManager;
+import org.briarproject.bramble.api.contact.PendingContact;
+import org.briarproject.bramble.api.contact.PendingContactId;
+import org.briarproject.bramble.api.contact.event.ContactAddedRemotelyEvent;
+import org.briarproject.bramble.api.contact.event.PendingContactRemovedEvent;
+import org.briarproject.bramble.api.contact.event.PendingContactStateChangedEvent;
+import org.briarproject.bramble.api.db.DatabaseExecutor;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventListener;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.util.Collection;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+@NotNullByDefault
+public class PendingContactListViewModel extends AndroidViewModel
+		implements EventListener {
+
+	private final Logger LOG =
+			getLogger(PendingContactListViewModel.class.getName());
+
+	@DatabaseExecutor
+	private final Executor dbExecutor;
+	private final ContactManager contactManager;
+	private final EventBus eventBus;
+
+	private final MutableLiveData<Collection<PendingContact>> pendingContacts =
+			new MutableLiveData<>();
+
+	@Inject
+	public PendingContactListViewModel(Application application,
+			@DatabaseExecutor Executor dbExecutor,
+			ContactManager contactManager, EventBus eventBus) {
+		super(application);
+		this.dbExecutor = dbExecutor;
+		this.contactManager = contactManager;
+		this.eventBus = eventBus;
+		this.eventBus.addListener(this);
+		loadPendingContacts();
+	}
+
+	@Override
+	protected void onCleared() {
+		super.onCleared();
+		eventBus.removeListener(this);
+	}
+
+	@Override
+	public void eventOccurred(Event e) {
+		if (e instanceof ContactAddedRemotelyEvent ||
+				e instanceof PendingContactStateChangedEvent ||
+				e instanceof PendingContactRemovedEvent) {
+			loadPendingContacts();
+		}
+	}
+
+	private void loadPendingContacts() {
+		dbExecutor.execute(() -> {
+			try {
+				pendingContacts.postValue(contactManager.getPendingContacts());
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	LiveData<Collection<PendingContact>> getPendingContacts() {
+		return pendingContacts;
+	}
+
+	void removePendingContact(PendingContactId id) {
+		dbExecutor.execute(() -> {
+			try {
+				contactManager.removePendingContact(id);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/contact/add/remote/PendingContactListener.java

@@ -0,0 +1,9 @@
+package org.briarproject.briar.android.contact.add.remote;
+
+import org.briarproject.bramble.api.contact.PendingContact;
+
+interface PendingContactListener {
+
+	void onFailedPendingContactRemoved(PendingContact pendingContact);
+
+}

briar-android/src/main/java/org/briarproject/briar/android/contact/add/remote/PendingContactViewHolder.java

@@ -0,0 +1,77 @@
+package org.briarproject.briar.android.contact.add.remote;
+
+import android.support.v4.content.ContextCompat;
+import android.support.v7.widget.RecyclerView.ViewHolder;
+import android.view.View;
+import android.widget.Button;
+import android.widget.TextView;
+
+import org.briarproject.bramble.api.contact.PendingContact;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.view.TextAvatarView;
+
+import static android.view.View.GONE;
+import static android.view.View.VISIBLE;
+import static org.briarproject.briar.android.util.UiUtils.formatDate;
+
+@NotNullByDefault
+class PendingContactViewHolder extends ViewHolder {
+
+	private final PendingContactListener listener;
+	private final TextAvatarView avatar;
+	private final TextView name;
+	private final TextView time;
+	private final TextView status;
+	private final Button removeButton;
+
+	PendingContactViewHolder(View v, PendingContactListener listener) {
+		super(v);
+		avatar = v.findViewById(R.id.avatar);
+		name = v.findViewById(R.id.name);
+		time = v.findViewById(R.id.time);
+		status = v.findViewById(R.id.status);
+		removeButton = v.findViewById(R.id.removeButton);
+		this.listener = listener;
+	}
+
+	public void bind(PendingContact item) {
+		avatar.setText(item.getAlias());
+		avatar.setBackgroundBytes(item.getId().getBytes());
+		name.setText(item.getAlias());
+		time.setText(formatDate(time.getContext(), item.getTimestamp()));
+		removeButton.setOnClickListener(v -> {
+			listener.onFailedPendingContactRemoved(item);
+			removeButton.setEnabled(false);
+		});
+
+		int color = ContextCompat
+				.getColor(status.getContext(), R.color.briar_green);
+		int buttonVisibility = GONE;
+		switch (item.getState()) {
+			case WAITING_FOR_CONNECTION:
+				color = ContextCompat
+						.getColor(status.getContext(), R.color.briar_yellow);
+				status.setText(R.string.waiting_for_contact_to_come_online);
+				break;
+			case CONNECTED:
+				status.setText(R.string.connecting);
+				break;
+			case ADDING_CONTACT:
+				status.setText(R.string.adding_contact);
+				break;
+			case FAILED:
+				color = ContextCompat
+						.getColor(status.getContext(), R.color.briar_red);
+				status.setText(R.string.adding_contact_failed);
+				buttonVisibility = VISIBLE;
+				break;
+			default:
+				throw new IllegalStateException();
+		}
+		status.setTextColor(color);
+		removeButton.setVisibility(buttonVisibility);
+		removeButton.setEnabled(true);
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationActivity.java

@@ -59,6 +59,7 @@ import org.briarproject.briar.android.conversation.ConversationVisitor.TextCache
 import org.briarproject.briar.android.forum.ForumActivity;
 import org.briarproject.briar.android.introduction.IntroductionActivity;
 import org.briarproject.briar.android.privategroup.conversation.GroupActivity;
+import org.briarproject.briar.android.util.BriarSnackbarBuilder;
 import org.briarproject.briar.android.view.BriarRecyclerView;
 import org.briarproject.briar.android.view.ImagePreview;
 import org.briarproject.briar.android.view.TextAttachmentController;
@@ -296,10 +297,10 @@ public class ConversationActivity extends BriarActivity
 		super.onActivityResult(request, result, data);
 
 		if (request == REQUEST_INTRODUCTION && result == RESULT_OK) {
-			Snackbar snackbar = Snackbar.make(list, R.string.introduction_sent,
-					Snackbar.LENGTH_SHORT);
-			snackbar.getView().setBackgroundResource(R.color.briar_primary);
-			snackbar.show();
+			new BriarSnackbarBuilder()
+					.make(list, R.string.introduction_sent,
+							Snackbar.LENGTH_SHORT)
+					.show();
 		} else if (request == REQUEST_ATTACH_IMAGE && result == RESULT_OK) {
 			// remove cast when removing FEATURE_FLAG_IMAGE_ATTACHMENTS
 			((TextAttachmentController) sendController).onImageReceived(data);
@@ -362,7 +363,7 @@ public class ConversationActivity extends BriarActivity
 			if (enable != null && enable) {
 				menu.findItem(R.id.action_introduction).setEnabled(true);
 				// show introduction onboarding, if needed
-				observeOnce(viewModel.showIntroductionOnboarding(), this,
+				viewModel.showIntroductionOnboarding().observeEvent(this,
 						this::showIntroductionOnboarding);
 			}
 		});
@@ -473,9 +474,8 @@ public class ConversationActivity extends BriarActivity
 			if (revision == adapter.getRevision()) {
 				adapter.incrementRevision();
 				textInputView.setReady(true);
-				// start observing onboarding after enabling (only once, because
-				// we only update this when an onboarding should be shown)
-				observeOnce(viewModel.showImageOnboarding(), this,
+				// start observing onboarding after enabling
+				viewModel.showImageOnboarding().observeEvent(this,
 						this::showImageOnboarding);
 				List<ConversationItem> items = createItems(headers);
 				adapter.addAll(items);
@@ -498,7 +498,6 @@ public class ConversationActivity extends BriarActivity
 	 * <p>
 	 * Attention: Call this only after contactName has been initialized.
 	 */
-	@SuppressWarnings("ConstantConditions")
 	private List<ConversationItem> createItems(
 			Collection<ConversationMessageHeader> headers) {
 		List<ConversationItem> items = new ArrayList<>(headers.size());
@@ -714,8 +713,8 @@ public class ConversationActivity extends BriarActivity
 		});
 	}
 
-	private void showImageOnboarding(@Nullable Boolean show) {
-		if (show == null || !show) return;
+	private void showImageOnboarding(Boolean show) {
+		if (!show) return;
 		if (SDK_INT >= 21) {
 			// show onboarding only after the enter transition has ended
 			// otherwise the tap target animation won't play

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationViewModel.java

@@ -28,6 +28,8 @@ import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.briar.android.util.UiUtils;
+import org.briarproject.briar.android.viewmodel.LiveEvent;
+import org.briarproject.briar.android.viewmodel.MutableLiveEvent;
 import org.briarproject.briar.api.messaging.Attachment;
 import org.briarproject.briar.api.messaging.AttachmentHeader;
 import org.briarproject.briar.api.messaging.MessagingManager;
@@ -87,10 +89,10 @@ public class ConversationViewModel extends AndroidViewModel {
 			Transformations.map(contact, UiUtils::getContactDisplayName);
 	private final MutableLiveData<Boolean> imageSupport =
 			new MutableLiveData<>();
-	private final MutableLiveData<Boolean> showImageOnboarding =
-			new MutableLiveData<>();
-	private final MutableLiveData<Boolean> showIntroductionOnboarding =
-			new MutableLiveData<>();
+	private final MutableLiveEvent<Boolean> showImageOnboarding =
+			new MutableLiveEvent<>();
+	private final MutableLiveEvent<Boolean> showIntroductionOnboarding =
+			new MutableLiveEvent<>();
 	private final MutableLiveData<Boolean> showIntroductionAction =
 			new MutableLiveData<>();
 	private final MutableLiveData<Boolean> contactDeleted =
@@ -212,32 +214,30 @@ public class ConversationViewModel extends AndroidViewModel {
 		if (imagesSupported &&
 				settings.getBoolean(SHOW_ONBOARDING_IMAGE, true)) {
 			// check if we should show onboarding, only if images are supported
-			showImageOnboarding.postValue(true);
+			showImageOnboarding.postEvent(true);
 			// allow observer to stop listening for changes
-			showIntroductionOnboarding.postValue(false);
+			showIntroductionOnboarding.postEvent(false);
 		} else {
 			// allow observer to stop listening for changes
-			showImageOnboarding.postValue(false);
+			showImageOnboarding.postEvent(false);
 			// we only show one onboarding dialog at a time
 			if (introductionSupported &&
 					settings.getBoolean(SHOW_ONBOARDING_INTRODUCTION, true)) {
-				showIntroductionOnboarding.postValue(true);
+				showIntroductionOnboarding.postEvent(true);
 			} else {
 				// allow observer to stop listening for changes
-				showIntroductionOnboarding.postValue(false);
+				showIntroductionOnboarding.postEvent(false);
 			}
 		}
 	}
 
 	@UiThread
 	void onImageOnboardingSeen() {
-		showImageOnboarding.setValue(false);
 		onOnboardingSeen(SHOW_ONBOARDING_IMAGE);
 	}
 
 	@UiThread
 	void onIntroductionOnboardingSeen() {
-		showIntroductionOnboarding.setValue(false);
 		onOnboardingSeen(SHOW_ONBOARDING_INTRODUCTION);
 	}
 
@@ -365,11 +365,11 @@ public class ConversationViewModel extends AndroidViewModel {
 		return imageSupport;
 	}
 
-	LiveData<Boolean> showImageOnboarding() {
+	LiveEvent<Boolean> showImageOnboarding() {
 		return showImageOnboarding;
 	}
 
-	LiveData<Boolean> showIntroductionOnboarding() {
+	LiveEvent<Boolean> showIntroductionOnboarding() {
 		return showIntroductionOnboarding;
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/conversation/ImageActivity.java

@@ -9,7 +9,6 @@ import android.os.Bundle;
 import android.support.annotation.Nullable;
 import android.support.annotation.RequiresApi;
 import android.support.design.widget.AppBarLayout;
-import android.support.design.widget.Snackbar;
 import android.support.v4.app.Fragment;
 import android.support.v4.app.FragmentManager;
 import android.support.v4.app.FragmentStatePagerAdapter;
@@ -32,6 +31,7 @@ import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
+import org.briarproject.briar.android.util.BriarSnackbarBuilder;
 import org.briarproject.briar.android.view.PullDownLayout;
 
 import java.text.SimpleDateFormat;
@@ -100,7 +100,8 @@ public class ImageActivity extends BriarActivity
 		// get View Model
 		viewModel = ViewModelProviders.of(this, viewModelFactory)
 				.get(ImageViewModel.class);
-		viewModel.getSaveState().observe(this, this::onImageSaveStateChanged);
+		viewModel.getSaveState().observeEvent(this,
+				this::onImageSaveStateChanged);
 
 		// inflate layout
 		setContentView(R.layout.activity_image);
@@ -141,7 +142,8 @@ public class ImageActivity extends BriarActivity
 		viewPager.setCurrentItem(position);
 
 		if (SDK_INT >= 16) {
-			viewModel.getOnImageClicked().observe(this, this::onImageClicked);
+			viewModel.getOnImageClicked()
+					.observeEvent(this, this::onImageClicked);
 			window.getDecorView().setSystemUiVisibility(UI_FLAGS_DEFAULT);
 		}
 	}
@@ -222,7 +224,6 @@ public class ImageActivity extends BriarActivity
 	private void onImageClicked(@Nullable Boolean clicked) {
 		if (clicked != null && clicked) {
 			toggleSystemUi();
-			viewModel.onOnImageClickSeen();
 		}
 	}
 
@@ -308,10 +309,10 @@ public class ImageActivity extends BriarActivity
 				R.string.save_image_error : R.string.save_image_success;
 		int colorRes = error ?
 				R.color.briar_red : R.color.briar_primary;
-		Snackbar s = Snackbar.make(layout, stringRes, LENGTH_LONG);
-		s.getView().setBackgroundResource(colorRes);
-		s.show();
-		viewModel.onSaveStateSeen();
+		new BriarSnackbarBuilder()
+				.setBackgroundColor(colorRes)
+				.make(layout, stringRes, LENGTH_LONG)
+				.show();
 	}
 
 	AttachmentItem getVisibleAttachment() {

briar-android/src/main/java/org/briarproject/briar/android/conversation/ImageViewModel.java

@@ -2,8 +2,6 @@ package org.briarproject.briar.android.conversation;
 
 import android.app.Application;
 import android.arch.lifecycle.AndroidViewModel;
-import android.arch.lifecycle.LiveData;
-import android.arch.lifecycle.MutableLiveData;
 import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.support.annotation.Nullable;
@@ -15,6 +13,8 @@ import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.briar.android.viewmodel.LiveEvent;
+import org.briarproject.briar.android.viewmodel.MutableLiveEvent;
 import org.briarproject.briar.api.messaging.Attachment;
 import org.briarproject.briar.api.messaging.MessagingManager;
 
@@ -53,9 +53,10 @@ public class ImageViewModel extends AndroidViewModel {
 	/**
 	 * true means there was an error saving the image, false if image was saved.
 	 */
-	private final MutableLiveData<Boolean> saveState = new MutableLiveData<>();
-	private final MutableLiveData<Boolean> imageClicked =
-			new MutableLiveData<>();
+	private final MutableLiveEvent<Boolean> saveState =
+			new MutableLiveEvent<>();
+	private final MutableLiveEvent<Boolean> imageClicked =
+			new MutableLiveEvent<>();
 	private int toolbarTop, toolbarBottom;
 
 	@Inject
@@ -70,24 +71,17 @@ public class ImageViewModel extends AndroidViewModel {
 	}
 
 	void clickImage() {
-		imageClicked.setValue(true);
+		imageClicked.setEvent(true);
 	}
 
 	/**
-	 * A LiveData that is true if the image was clicked,
+	 * A LiveEvent that is true if the image was clicked,
 	 * false if it wasn't.
-	 *
-	 * Call {@link #onOnImageClickSeen()} after consuming an update.
 	 */
-	LiveData<Boolean> getOnImageClicked() {
+	LiveEvent<Boolean> getOnImageClicked() {
 		return imageClicked;
 	}
 
-	@UiThread
-	void onOnImageClickSeen() {
-		imageClicked.setValue(false);
-	}
-
 	void setToolbarPosition(int top, int bottom) {
 		toolbarTop = top;
 		toolbarBottom = bottom;
@@ -111,26 +105,18 @@ public class ImageViewModel extends AndroidViewModel {
 	/**
 	 * A LiveData that is true if there was an error
 	 * and false if the image was saved.
-	 * It can be null otherwise, if no image was saved recently.
-	 *
-	 * Call {@link #onSaveStateSeen()} after consuming an update.
 	 */
-	LiveData<Boolean> getSaveState() {
+	LiveEvent<Boolean> getSaveState() {
 		return saveState;
 	}
 
-	@UiThread
-	void onSaveStateSeen() {
-		saveState.setValue(null);
-	}
-
 	/**
 	 * Saves the attachment to a writeable {@link Uri}.
 	 */
 	@UiThread
 	void saveImage(AttachmentItem attachment, @Nullable Uri uri) {
 		if (uri == null) {
-			saveState.setValue(true);
+			saveState.setEvent(true);
 		} else {
 			saveImage(attachment, () -> getOutputStream(uri), null);
 		}
@@ -155,7 +141,7 @@ public class ImageViewModel extends AndroidViewModel {
 				copyImageFromDb(a, osp, afterCopy);
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
-				saveState.postValue(true);
+				saveState.postEvent(true);
 			}
 		});
 	}
@@ -168,10 +154,10 @@ public class ImageViewModel extends AndroidViewModel {
 				OutputStream os = osp.getOutputStream();
 				copyAndClose(is, os);
 				if (afterCopy != null) afterCopy.run();
-				saveState.postValue(false);
+				saveState.postEvent(false);
 			} catch (IOException e) {
 				logException(LOG, WARNING, e);
-				saveState.postValue(true);
+				saveState.postEvent(true);
 			}
 		});
 	}

briar-android/src/main/java/org/briarproject/briar/android/forum/ForumListFragment.java

@@ -4,7 +4,6 @@ import android.content.Intent;
 import android.os.Bundle;
 import android.support.annotation.UiThread;
 import android.support.design.widget.Snackbar;
-import android.support.v4.content.ContextCompat;
 import android.support.v7.widget.LinearLayoutManager;
 import android.view.LayoutInflater;
 import android.view.Menu;
@@ -27,6 +26,7 @@ import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.fragment.BaseEventFragment;
 import org.briarproject.briar.android.sharing.ForumInvitationActivity;
+import org.briarproject.briar.android.util.BriarSnackbarBuilder;
 import org.briarproject.briar.android.view.BriarRecyclerView;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
 import org.briarproject.briar.api.client.MessageTracker.GroupCount;
@@ -105,11 +105,9 @@ public class ForumListFragment extends BaseEventFragment implements
 		list.setLayoutManager(new LinearLayoutManager(getActivity()));
 		list.setAdapter(adapter);
 
-		snackbar = Snackbar.make(list, "", LENGTH_INDEFINITE);
-		snackbar.getView().setBackgroundResource(R.color.briar_primary);
-		snackbar.setAction(R.string.show, this);
-		snackbar.setActionTextColor(ContextCompat
-				.getColor(getActivity(), R.color.briar_button_text_positive));
+		snackbar = new BriarSnackbarBuilder()
+				.setAction(R.string.show, this)
+				.make(list, "", LENGTH_INDEFINITE);
 
 		return contentView;
 	}

briar-android/src/main/java/org/briarproject/briar/android/keyagreement/KeyAgreementFragment.java

@@ -15,6 +15,7 @@ import android.widget.Toast;
 
 import com.google.zxing.Result;
 
+import org.briarproject.bramble.api.UnsupportedVersionException;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementResult;
@@ -22,7 +23,6 @@ import org.briarproject.bramble.api.keyagreement.KeyAgreementTask;
 import org.briarproject.bramble.api.keyagreement.Payload;
 import org.briarproject.bramble.api.keyagreement.PayloadEncoder;
 import org.briarproject.bramble.api.keyagreement.PayloadParser;
-import org.briarproject.bramble.api.keyagreement.UnsupportedVersionException;
 import org.briarproject.bramble.api.keyagreement.event.KeyAgreementAbortedEvent;
 import org.briarproject.bramble.api.keyagreement.event.KeyAgreementFailedEvent;
 import org.briarproject.bramble.api.keyagreement.event.KeyAgreementFinishedEvent;

briar-android/src/main/java/org/briarproject/briar/android/privategroup/conversation/GroupActivity.java

@@ -4,7 +4,6 @@ import android.content.DialogInterface;
 import android.content.DialogInterface.OnClickListener;
 import android.content.Intent;
 import android.os.Bundle;
-import android.support.annotation.StringRes;
 import android.support.v7.app.AlertDialog;
 import android.support.v7.widget.LinearLayoutManager;
 import android.support.v7.widget.Toolbar;
@@ -198,7 +197,7 @@ public class GroupActivity extends
 
 	private void setGroupEnabled(boolean enabled) {
 		isDissolved = !enabled;
-		textInput.setEnabled(enabled);
+		sendController.setReady(enabled);
 		list.getRecyclerView().setAlpha(enabled ? 1f : 0.5f);
 
 		if (!enabled) {

briar-android/src/main/java/org/briarproject/briar/android/privategroup/list/GroupListFragment.java

@@ -4,7 +4,6 @@ import android.content.Intent;
 import android.os.Bundle;
 import android.support.annotation.UiThread;
 import android.support.design.widget.Snackbar;
-import android.support.v4.content.ContextCompat;
 import android.support.v7.widget.LinearLayoutManager;
 import android.view.LayoutInflater;
 import android.view.Menu;
@@ -27,6 +26,7 @@ import org.briarproject.briar.android.privategroup.creation.CreateGroupActivity;
 import org.briarproject.briar.android.privategroup.invitation.GroupInvitationActivity;
 import org.briarproject.briar.android.privategroup.list.GroupListController.GroupListListener;
 import org.briarproject.briar.android.privategroup.list.GroupViewHolder.OnGroupRemoveClickListener;
+import org.briarproject.briar.android.util.BriarSnackbarBuilder;
 import org.briarproject.briar.android.view.BriarRecyclerView;
 import org.briarproject.briar.api.privategroup.GroupMessageHeader;
 
@@ -82,11 +82,9 @@ public class GroupListFragment extends BaseFragment implements
 		list.setLayoutManager(new LinearLayoutManager(getContext()));
 		list.setAdapter(adapter);
 
-		snackbar = Snackbar.make(list, "", LENGTH_INDEFINITE);
-		snackbar.getView().setBackgroundResource(R.color.briar_primary);
-		snackbar.setAction(R.string.show, this);
-		snackbar.setActionTextColor(ContextCompat
-				.getColor(getActivity(), R.color.briar_button_text_positive));
+		snackbar = new BriarSnackbarBuilder()
+				.setAction(R.string.show, this)
+				.make(list, "", LENGTH_INDEFINITE);
 
 		return v;
 	}

briar-android/src/main/java/org/briarproject/briar/android/sharing/BaseMessageFragment.java

@@ -28,6 +28,7 @@ public abstract class BaseMessageFragment extends BaseFragment
 		implements SendListener {
 
 	protected LargeTextInputView message;
+	private TextSendController sendController;
 	private MessageFragmentListener listener;
 
 	@Override
@@ -45,8 +46,7 @@ public abstract class BaseMessageFragment extends BaseFragment
 		View v = inflater.inflate(R.layout.fragment_message, container,
 				false);
 		message = v.findViewById(R.id.messageView);
-		TextSendController sendController =
-				new TextSendController(message, this, true);
+		sendController = new TextSendController(message, this, true);
 		message.setSendController(sendController);
 		message.setMaxTextLength(listener.getMaximumTextLength());
 		message.setButtonText(getString(getButtonText()));
@@ -85,7 +85,7 @@ public abstract class BaseMessageFragment extends BaseFragment
 	@Override
 	public void onSendClick(@Nullable String text, List<Uri> imageUris) {
 		// disable button to prevent accidental double actions
-		message.setEnabled(false);
+		sendController.setReady(false);
 		message.hideSoftKeyboard();
 
 		listener.onButtonClick(text);

briar-android/src/main/java/org/briarproject/briar/android/threaded/ThreadListActivity.java

@@ -26,6 +26,7 @@ import org.briarproject.briar.android.controller.handler.UiResultExceptionHandle
 import org.briarproject.briar.android.threaded.ThreadItemAdapter.ThreadItemListener;
 import org.briarproject.briar.android.threaded.ThreadListController.ThreadListDataSource;
 import org.briarproject.briar.android.threaded.ThreadListController.ThreadListListener;
+import org.briarproject.briar.android.util.BriarSnackbarBuilder;
 import org.briarproject.briar.android.view.BriarRecyclerView;
 import org.briarproject.briar.android.view.KeyboardAwareLinearLayout;
 import org.briarproject.briar.android.view.TextInputView;
@@ -41,7 +42,6 @@ import java.util.logging.Logger;
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 
-import static android.support.design.widget.Snackbar.make;
 import static android.support.v7.widget.RecyclerView.NO_POSITION;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 
@@ -62,6 +62,7 @@ public abstract class ThreadListActivity<G extends NamedGroup, I extends ThreadI
 	protected BriarRecyclerView list;
 	private LinearLayoutManager layoutManager;
 	protected TextInputView textInput;
+	protected TextSendController sendController;
 	protected GroupId groupId;
 	@Nullable
 	private Parcelable layoutManagerState;
@@ -87,8 +88,7 @@ public abstract class ThreadListActivity<G extends NamedGroup, I extends ThreadI
 		getController().setGroupId(groupId);
 
 		textInput = findViewById(R.id.text_input_container);
-		TextSendController sendController =
-				new TextSendController(textInput, this, false);
+		sendController = new TextSendController(textInput, this, false);
 		textInput.setSendController(sendController);
 		textInput.setMaxTextLength(getMaxTextLength());
 		textInput.setReady(true);
@@ -324,9 +324,9 @@ public abstract class ThreadListActivity<G extends NamedGroup, I extends ThreadI
 	}
 
 	protected void displaySnackbar(@StringRes int stringId) {
-		Snackbar snackbar = make(list, stringId, Snackbar.LENGTH_SHORT);
-		snackbar.getView().setBackgroundResource(R.color.briar_primary);
-		snackbar.show();
+		new BriarSnackbarBuilder()
+				.make(list, stringId, Snackbar.LENGTH_SHORT)
+				.show();
 	}
 
 	private void updateTextInput() {

briar-android/src/main/java/org/briarproject/briar/android/util/BriarSnackbarBuilder.java

@@ -0,0 +1,53 @@
+package org.briarproject.briar.android.util;
+
+import android.support.annotation.ColorRes;
+import android.support.annotation.Nullable;
+import android.support.annotation.StringRes;
+import android.support.design.widget.Snackbar;
+import android.view.View;
+import android.view.View.OnClickListener;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.R;
+
+import static android.support.v4.content.ContextCompat.getColor;
+
+@NotNullByDefault
+public class BriarSnackbarBuilder {
+
+	@ColorRes
+	private int backgroundResId = R.color.briar_primary;
+	@StringRes
+	private int actionResId;
+	@Nullable
+	private OnClickListener onClickListener;
+
+	public Snackbar make(View view, CharSequence text, int duration) {
+		Snackbar s = Snackbar.make(view, text, duration);
+		s.getView().setBackgroundResource(backgroundResId);
+		if (onClickListener != null) {
+			s.setActionTextColor(getColor(view.getContext(),
+					R.color.briar_button_text_positive));
+			s.setAction(actionResId, onClickListener);
+		}
+		return s;
+	}
+
+	public Snackbar make(View view, @StringRes int resId, int duration) {
+		return make(view, view.getResources().getText(resId), duration);
+	}
+
+	public BriarSnackbarBuilder setBackgroundColor(
+			@ColorRes int backgroundResId) {
+		this.backgroundResId = backgroundResId;
+		return this;
+	}
+
+	public BriarSnackbarBuilder setAction(@StringRes int actionResId,
+			OnClickListener onClickListener) {
+		this.actionResId = actionResId;
+		this.onClickListener = onClickListener;
+		return this;
+	}
+
+}