WIP: Store descriptor in metadata so invite can be deleted.

WIP: Test effect of deleting private messages on delivery.
Merge branch 'location-permission-sdk-23' into 'master'
2026-04-18 22:18:14 +02:00 · 2018-11-27 12:44:45 +00:00 · 2018-11-27 10:07:16 +00:00 · 2018-11-22 12:03:07 +00:00 · 2018-11-20 16:16:47 +00:00 · 2018-11-16 13:44:39 +00:00
794 changed files with 19436 additions and 13701 deletions
@@ -11,8 +11,8 @@ test:
      - .gradle/caches

  script:
-    - ./gradlew --no-daemon animalSnifferMain animalSnifferTest
-    - ./gradlew --no-daemon test
+    - ./gradlew --no-daemon -Djava.security.egd=file:/dev/urandom animalSnifferMain animalSnifferTest
+    - ./gradlew --no-daemon -Djava.security.egd=file:/dev/urandom test --continue

  after_script:
    # these file change every time but should not be cached
@@ -36,6 +36,9 @@
      <option name="JD_ALIGN_PARAM_COMMENTS" value="false" />
      <option name="JD_ALIGN_EXCEPTION_COMMENTS" value="false" />
    </JavaCodeStyleSettings>
+    <JetCodeStyleSettings>
+      <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
+    </JetCodeStyleSettings>
    <Objective-C-extensions>
      <file>
        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Import" />
@@ -257,5 +260,11 @@
        </rules>
      </arrangement>
    </codeStyleSettings>
+    <codeStyleSettings language="kotlin">
+      <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
+      <option name="PARAMETER_ANNOTATION_WRAP" value="1" />
+      <option name="VARIABLE_ANNOTATION_WRAP" value="1" />
+      <option name="ENUM_CONSTANTS_WRAP" value="1" />
+    </codeStyleSettings>
  </code_scheme>
 </component>
@@ -0,0 +1,20 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All in briar-headless" type="AndroidJUnit" factoryName="Android JUnit" nameIsGenerated="true">
+    <module name="briar-headless" />
+    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
+    <option name="ALTERNATIVE_JRE_PATH" />
+    <option name="PACKAGE_NAME" value="org.briarproject.briar.headless" />
+    <option name="MAIN_CLASS_NAME" value="" />
+    <option name="METHOD_NAME" value="" />
+    <option name="TEST_OBJECT" value="package" />
+    <option name="VM_PARAMETERS" value="" />
+    <option name="PARAMETERS" value="" />
+    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/briar-headless" />
+    <option name="PASS_PARENT_ENVS" value="true" />
+    <option name="TEST_SEARCH_SCOPE">
+      <value defaultName="singleModule" />
+    </option>
+    <patterns />
+    <method />
+  </configuration>
+</component>
@@ -22,8 +22,9 @@
      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in bramble-api" run_configuration_type="AndroidJUnit" />
      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in bramble-core" run_configuration_type="AndroidJUnit" />
      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in bramble-android" run_configuration_type="AndroidJUnit" />
-      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in bramble-j2se" run_configuration_type="AndroidJUnit" />
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in bramble-java" run_configuration_type="AndroidJUnit" />
      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in briar-core" run_configuration_type="AndroidJUnit" />
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All in briar-headless" run_configuration_type="AndroidJUnit" />
    </method>
  </configuration>
 </component>
@@ -1,6 +1,5 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="All tests in bramble-android" type="AndroidJUnit" factoryName="Android JUnit">
-    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
    <module name="bramble-android" />
    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
    <option name="ALTERNATIVE_JRE_PATH" />
@@ -11,12 +10,10 @@
    <option name="VM_PARAMETERS" value="-ea" />
    <option name="PARAMETERS" value="" />
    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/bramble-android" />
-    <option name="ENV_VARIABLES" />
    <option name="PASS_PARENT_ENVS" value="true" />
    <option name="TEST_SEARCH_SCOPE">
      <value defaultName="singleModule" />
    </option>
-    <envs />
    <patterns />
    <method />
  </configuration>
@@ -1,6 +1,5 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="All tests in bramble-api" type="AndroidJUnit" factoryName="Android JUnit">
-    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
    <module name="bramble-api" />
    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
    <option name="ALTERNATIVE_JRE_PATH" />
@@ -11,12 +10,10 @@
    <option name="VM_PARAMETERS" value="-ea" />
    <option name="PARAMETERS" value="" />
    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/bramble-api" />
-    <option name="ENV_VARIABLES" />
    <option name="PASS_PARENT_ENVS" value="true" />
    <option name="TEST_SEARCH_SCOPE">
      <value defaultName="singleModule" />
    </option>
-    <envs />
    <patterns />
    <method />
  </configuration>
@@ -1,6 +1,5 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="All tests in bramble-core" type="AndroidJUnit" factoryName="Android JUnit">
-    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
    <module name="bramble-core" />
    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
    <option name="ALTERNATIVE_JRE_PATH" />
@@ -11,12 +10,10 @@
    <option name="VM_PARAMETERS" value="-ea" />
    <option name="PARAMETERS" value="" />
    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/bramble-core" />
-    <option name="ENV_VARIABLES" />
    <option name="PASS_PARENT_ENVS" value="true" />
    <option name="TEST_SEARCH_SCOPE">
      <value defaultName="singleModule" />
    </option>
-    <envs />
    <patterns />
    <method />
  </configuration>
@@ -1,7 +1,6 @@
 <component name="ProjectRunConfigurationManager">
-  <configuration default="false" name="All tests in bramble-j2se" type="AndroidJUnit" factoryName="Android JUnit">
-    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
-    <module name="bramble-j2se" />
+  <configuration default="false" name="All tests in bramble-java" type="AndroidJUnit" factoryName="Android JUnit">
+    <module name="bramble-java" />
    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
    <option name="ALTERNATIVE_JRE_PATH" />
    <option name="PACKAGE_NAME" value="" />
@@ -10,13 +9,11 @@
    <option name="TEST_OBJECT" value="package" />
    <option name="VM_PARAMETERS" value="-ea -Djava.library.path=libs" />
    <option name="PARAMETERS" value="" />
-    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/bramble-j2se" />
-    <option name="ENV_VARIABLES" />
+    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/bramble-java" />
    <option name="PASS_PARENT_ENVS" value="true" />
    <option name="TEST_SEARCH_SCOPE">
      <value defaultName="singleModule" />
    </option>
-    <envs />
    <patterns />
    <method />
  </configuration>
@@ -1,6 +1,5 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="All tests in briar-android" type="AndroidJUnit" factoryName="Android JUnit">
-    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
    <module name="briar-android" />
    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
    <option name="ALTERNATIVE_JRE_PATH" />
@@ -11,12 +10,10 @@
    <option name="VM_PARAMETERS" value="-ea" />
    <option name="PARAMETERS" value="" />
    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/briar-android" />
-    <option name="ENV_VARIABLES" />
    <option name="PASS_PARENT_ENVS" value="true" />
    <option name="TEST_SEARCH_SCOPE">
      <value defaultName="singleModule" />
    </option>
-    <envs />
    <patterns />
    <method />
  </configuration>
@@ -1,6 +1,5 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="All tests in briar-core" type="AndroidJUnit" factoryName="Android JUnit">
-    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
    <module name="briar-core" />
    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
    <option name="ALTERNATIVE_JRE_PATH" />
@@ -11,12 +10,10 @@
    <option name="VM_PARAMETERS" value="-ea" />
    <option name="PARAMETERS" value="" />
    <option name="WORKING_DIRECTORY" value="file://$PROJECT_DIR$/briar-core" />
-    <option name="ENV_VARIABLES" />
    <option name="PASS_PARENT_ENVS" value="true" />
    <option name="TEST_SEARCH_SCOPE">
      <value defaultName="singleModule" />
    </option>
-    <envs />
    <patterns />
    <method />
  </configuration>
@@ -1,6 +1,5 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="H2 Performance Test" type="AndroidJUnit" factoryName="Android JUnit">
-    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
    <module name="bramble-core" />
    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
    <option name="ALTERNATIVE_JRE_PATH" />
@@ -11,12 +10,10 @@
    <option name="VM_PARAMETERS" value="-ea" />
    <option name="PARAMETERS" value="" />
    <option name="WORKING_DIRECTORY" value="" />
-    <option name="ENV_VARIABLES" />
    <option name="PASS_PARENT_ENVS" value="true" />
    <option name="TEST_SEARCH_SCOPE">
      <value defaultName="singleModule" />
    </option>
-    <envs />
    <patterns />
    <method />
  </configuration>
@@ -1,6 +1,5 @@
 <component name="ProjectRunConfigurationManager">
  <configuration default="false" name="HyperSQL Performance Test" type="AndroidJUnit" factoryName="Android JUnit">
-    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
    <module name="bramble-core" />
    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
    <option name="ALTERNATIVE_JRE_PATH" />
@@ -11,12 +10,10 @@
    <option name="VM_PARAMETERS" value="-ea" />
    <option name="PARAMETERS" value="" />
    <option name="WORKING_DIRECTORY" value="" />
-    <option name="ENV_VARIABLES" />
    <option name="PASS_PARENT_ENVS" value="true" />
    <option name="TEST_SEARCH_SCOPE">
      <value defaultName="singleModule" />
    </option>
-    <envs />
    <patterns />
    <method />
  </configuration>
@@ -0,0 +1,17 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="briar-headless" type="JetRunConfigurationType" factoryName="Kotlin" singleton="true">
+    <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
+    <option name="VM_PARAMETERS" value="" />
+    <option name="PROGRAM_PARAMETERS" value="-v" />
+    <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
+    <option name="ALTERNATIVE_JRE_PATH" />
+    <option name="PASS_PARENT_ENVS" value="true" />
+    <option name="MAIN_CLASS_NAME" value="org.briarproject.briar.headless.MainKt" />
+    <option name="WORKING_DIRECTORY" value="" />
+    <module name="briar-headless" />
+    <envs />
+    <method>
+      <option name="Gradle.BeforeRunTask" enabled="true" tasks="jar" externalProjectPath="$PROJECT_DIR$/briar-headless" vmOptions="" scriptParameters="" />
+    </method>
+  </configuration>
+</component>
@@ -1,15 +1,18 @@
+import com.android.build.gradle.tasks.MergeResources
+
 apply plugin: 'com.android.library'
 apply plugin: 'witness'
+apply from: 'witness.gradle'

 android {
-	compileSdkVersion 27
-	buildToolsVersion '27.0.3'
+	compileSdkVersion 28
+	buildToolsVersion '28.0.3'

 	defaultConfig {
 		minSdkVersion 14
 		targetSdkVersion 26
-		versionCode 10013
-		versionName "1.0.13"
+		versionCode 10105
+		versionName "1.1.5"
 		consumerProguardFiles 'proguard-rules.txt'

 		testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
@@ -27,10 +30,10 @@ configurations {

 dependencies {
 	implementation project(path: ':bramble-core', configuration: 'default')
-	implementation 'org.briarproject:jtorctl:0.3'
-	tor 'org.briarproject:tor-android:0.2.9.16@zip'
+	tor 'org.briarproject:tor-android:0.3.4.8@zip'
+	tor 'org.briarproject:obfs4proxy-android:0.0.7@zip'

-	annotationProcessor 'com.google.dagger:dagger-compiler:2.0.2'
+	annotationProcessor 'com.google.dagger:dagger-compiler:2.19'

 	compileOnly 'javax.annotation:jsr250-api:1.0'

@@ -39,115 +42,29 @@ dependencies {
 	testImplementation "org.jmock:jmock:2.8.2"
 	testImplementation "org.jmock:jmock-junit4:2.8.2"
 	testImplementation "org.jmock:jmock-legacy:2.8.2"
-	testImplementation "org.hamcrest:hamcrest-library:1.3"
-	testImplementation "org.hamcrest:hamcrest-core:1.3"
-
-	androidTestImplementation project(path: ':bramble-api', configuration: 'testOutput')
-	androidTestImplementation project(path: ':bramble-core', configuration: 'testOutput')
-	androidTestImplementation 'com.android.support.test:runner:1.0.2'
-	androidTestAnnotationProcessor 'com.google.dagger:dagger-compiler:2.0.2'
-	androidTestCompileOnly 'javax.annotation:jsr250-api:1.0'
 }

-dependencyVerification {
-	verify = [
-			'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
-			'com.android.support.test:monitor:1.0.2:monitor-1.0.2.aar:38ef4fa98a32dc55550ff49bb36a583e178b3a9b830fcb8dcc27bfc4254bc2bc',
-			'com.android.support.test:runner:1.0.2:runner-1.0.2.aar:f04b9ae342975ba1cb3e4a06e13426e3e6b8a73faa45acba604493d83c9a4f00',
-			'com.android.support:support-annotations:27.1.1:support-annotations-27.1.1.jar:3365960206c3d2b09e845f555e7f88f8effc8d2f00b369e66c4be384029299cf',
-			'com.android.tools.analytics-library:protos:26.1.3:protos-26.1.3.jar:818c9f256f141d9dafec03a1aa2b94d240b2c140acfd7ee31a8b3e6c2b9479e3',
-			'com.android.tools.analytics-library:shared:26.1.3:shared-26.1.3.jar:7110706c7ada96c8b6f5ca80c478291bc7899d46277de2c48527e045442401a3',
-			'com.android.tools.analytics-library:tracker:26.1.3:tracker-26.1.3.jar:4155424bf2ce4872da83332579a1707252bc66cbd77c5144fdc4483d0f2e1418',
-			'com.android.tools.build:apksig:3.1.3:apksig-3.1.3.jar:7e1f8e675a6e768e5b56405e41d6c3cc05befe62e601b04177de1029902c9c89',
-			'com.android.tools.build:builder-model:3.1.3:builder-model-3.1.3.jar:06ad1c422d679fc698451479cb40ba863849d67bfd1de23f6d2c16d78b024b0b',
-			'com.android.tools.build:builder-test-api:3.1.3:builder-test-api-3.1.3.jar:4d989f780436794f0f8b2f50e9e079b786571eac90f26c208ab2ae6d4012f389',
-			'com.android.tools.build:builder:3.1.3:builder-3.1.3.jar:8a1092012c89d0ec1ee2eff09c5708c71ef4482a6862df8d3a44a67fccace01c',
-			'com.android.tools.build:gradle-api:3.1.3:gradle-api-3.1.3.jar:01e4df521456aef66514336f1d492346730dd1fb8f6433a89f62da834941ed72',
-			'com.android.tools.build:manifest-merger:26.1.3:manifest-merger-26.1.3.jar:1e4fc7e932adb4607082409800e5e6fccb42e6c5360ae5990094bf522f3ada55',
-			'com.android.tools.ddms:ddmlib:26.1.3:ddmlib-26.1.3.jar:c54931cd68df5d1ea2923b3b320eae47cd2307a5a916bb8674c0acf93cd1d3cd',
-			'com.android.tools.external.com-intellij:intellij-core:26.1.3:intellij-core-26.1.3.jar:af67f5535fef2e1a28b1007a4acb8c5deb6a1e33b8afe7b11d012c9e778ebcec',
-			'com.android.tools.external.com-intellij:kotlin-compiler:26.1.3:kotlin-compiler-26.1.3.jar:c746d2859dc11cc05c84b692b3498d3a621e0929511f8440ee009c6557838fd4',
-			'com.android.tools.external.org-jetbrains:uast:26.1.3:uast-26.1.3.jar:3f3f6651d0c7685a77ecb22e9c82d6b49fdf24322c17360768dc530678f43265',
-			'com.android.tools.layoutlib:layoutlib-api:26.1.3:layoutlib-api-26.1.3.jar:10bc73ce706c45629872d6a999dbe12116df64e24f47ff93b7b13121ff57b4b0',
-			'com.android.tools.lint:lint-api:26.1.3:lint-api-26.1.3.jar:6f97323f9af8deda86278717885b5c927f3766757db89709f52d11d42b6fb751',
-			'com.android.tools.lint:lint-checks:26.1.3:lint-checks-26.1.3.jar:73c3d53784c9ce3e6d5968506581918e0179645d20809927ca4a001dd766b001',
-			'com.android.tools.lint:lint-gradle-api:26.1.3:lint-gradle-api-26.1.3.jar:7ca3c4866ec21dc21d53a9d86f752b77ace6f6c610a0c9dc877313856c733d9d',
-			'com.android.tools.lint:lint-gradle:26.1.3:lint-gradle-26.1.3.jar:db0c354b8f4b6f6637e31f91c564785a59ff896325331fcbc3de7458e0b6c067',
-			'com.android.tools.lint:lint-kotlin:26.1.3:lint-kotlin-26.1.3.jar:94e2b0f4565a241561cfb8fc1222bb3f132a3b98d2a90421dbb72ee8358e7d68',
-			'com.android.tools.lint:lint:26.1.3:lint-26.1.3.jar:8d5f32c989c6d191d712e90ad3ca2d1c409313599551d04d834caa44d26c78df',
-			'com.android.tools:annotations:26.1.3:annotations-26.1.3.jar:c950430b24ac5d58fc97e7283b8f0115f99587e76e08b4e1e2aaa780f2d77323',
-			'com.android.tools:common:26.1.3:common-26.1.3.jar:7c31a90581a148ab219f615a59667f0dded7fa39b248529784474da3c2274ef2',
-			'com.android.tools:dvlib:26.1.3:dvlib-26.1.3.jar:0cae87906f53d3f1088366a916ed180a7312b6d9919b90797f238875c8492855',
-			'com.android.tools:repository:26.1.3:repository-26.1.3.jar:52d4539cc68db91b261e2a33b2c8206b26e05539078758dc28cfb3854adb4f59',
-			'com.android.tools:sdk-common:26.1.3:sdk-common-26.1.3.jar:1948603ca9ff22c7ebb3178000bffa3a9dd2ca1cc5cb0c793cae08468b8fcfc1',
-			'com.android.tools:sdklib:26.1.3:sdklib-26.1.3.jar:4adcfaad9514607098d2c51503c39811112d3050f4d1e744c01c7f08f591032b',
-			'com.google.code.findbugs:jsr305:1.3.9:jsr305-1.3.9.jar:905721a0eea90a81534abb7ee6ef4ea2e5e645fa1def0a5cd88402df1b46c9ed',
-			'com.google.code.gson:gson:2.7:gson-2.7.jar:2d43eb5ea9e133d2ee2405cc14f5ee08951b8361302fdd93494a3a997b508d32',
-			'com.google.dagger:dagger-compiler:2.0.2:dagger-compiler-2.0.2.jar:b74bc9de063dd4c6400b232231f2ef5056145b8fbecbf5382012007dd1c071b3',
-			'com.google.dagger:dagger-producers:2.0-beta:dagger-producers-2.0-beta.jar:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
-			'com.google.dagger:dagger:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
-			'com.google.errorprone:error_prone_annotations:2.0.18:error_prone_annotations-2.0.18.jar:cb4cfad870bf563a07199f3ebea5763f0dec440fcda0b318640b1feaa788656b',
-			'com.google.guava:guava:18.0:guava-18.0.jar:d664fbfc03d2e5ce9cab2a44fb01f1d0bf9dfebeccc1a473b1f9ea31f79f6f99',
-			'com.google.guava:guava:22.0:guava-22.0.jar:1158e94c7de4da480873f0b4ab4a1da14c0d23d4b1902cc94a58a6f0f9ab579e',
-			'com.google.j2objc:j2objc-annotations:1.1:j2objc-annotations-1.1.jar:40ceb7157feb263949e0f503fe5f71689333a621021aa20ce0d0acee3badaa0f',
-			'com.google.jimfs:jimfs:1.1:jimfs-1.1.jar:c4828e28d7c0a930af9387510b3bada7daa5c04d7c25a75c7b8b081f1c257ddd',
-			'com.google.protobuf:protobuf-java:3.4.0:protobuf-java-3.4.0.jar:dce7e66b32456a1b1198da0caff3a8acb71548658391e798c79369241e6490a4',
-			'com.googlecode.json-simple:json-simple:1.1:json-simple-1.1.jar:2d9484f4c649f708f47f9a479465fc729770ee65617dca3011836602264f6439',
-			'com.squareup:javawriter:2.5.0:javawriter-2.5.0.jar:fcfb09fb0ea0aa97d3cfe7ea792398081348e468f126b3603cb3803f240197f0',
-			'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:1.6:commons-codec-1.6.jar:54b34e941b8e1414bd3e40d736efd3481772dc26db3296f6aa45cec9f6203d86',
-			'commons-logging:commons-logging:1.1.1:commons-logging-1.1.1.jar:ce6f913cad1f0db3aad70186d65c5bc7ffcc9a99e3fe8e0b137312819f7c362f',
-			'it.unimi.dsi:fastutil:7.2.0:fastutil-7.2.0.jar:74fa208043740642f7e6eb09faba15965218ad2f50ce3020efb100136e4b591c',
-			'javax.annotation:jsr250-api:1.0:jsr250-api-1.0.jar:a1a922d0d9b6d183ed3800dfac01d1e1eb159f0e8c6f94736931c1def54a941f',
-			'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
-			'javax.xml.bind:jaxb-api:2.2.12-b140109.1041:jaxb-api-2.2.12-b140109.1041.jar:b5e60cd8b7b5ff01ce4a74c5dd008f4fbd14ced3495d0b47b85cfedc182211f2',
-			'junit:junit:4.12:junit-4.12.jar:59721f0805e223d84b90677887d9ff567dc534d7c502ca903c0c2b17f05c116a',
-			'net.sf.jopt-simple:jopt-simple:4.9:jopt-simple-4.9.jar:26c5856e954b5f864db76f13b86919b59c6eecf9fd930b96baa8884626baf2f5',
-			'net.sf.kxml:kxml2:2.3.0:kxml2-2.3.0.jar:f264dd9f79a1fde10ce5ecc53221eff24be4c9331c830b7d52f2f08a7b633de2',
-			'org.apache.ant:ant-launcher:1.9.4:ant-launcher-1.9.4.jar:7bccea20b41801ca17bcbc909a78c835d0f443f12d639c77bd6ae3d05861608d',
-			'org.apache.ant:ant:1.9.4:ant-1.9.4.jar:649ae0730251de07b8913f49286d46bba7b92d47c5f332610aa426c4f02161d8',
-			'org.apache.commons:commons-compress:1.12:commons-compress-1.12.jar:2c1542faf343185b7cab9c3d55c8ae5471d6d095d3887a4adefdbdf2984dc0b6',
-			'org.apache.httpcomponents:httpclient:4.2.6:httpclient-4.2.6.jar:362e9324ee7c697e21279e20077b52737ddef3f1b2c1a7abe5ad34b465145550',
-			'org.apache.httpcomponents:httpcore:4.2.5:httpcore-4.2.5.jar:e5e82da4cc66c8d917bbf743e3c0752efe8522735e7fc9dbddb65bccea81cfe9',
-			'org.apache.httpcomponents:httpmime:4.1:httpmime-4.1.jar:31629566148e8a47688ae43b420abc3ecd783ed15b33bebc00824bf24c9b15aa',
-			'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
-			'org.bouncycastle:bcpkix-jdk15on:1.56:bcpkix-jdk15on-1.56.jar:7043dee4e9e7175e93e0b36f45b1ec1ecb893c5f755667e8b916eb8dd201c6ca',
-			'org.bouncycastle:bcprov-jdk15on:1.56:bcprov-jdk15on-1.56.jar:963e1ee14f808ffb99897d848ddcdb28fa91ddda867eb18d303e82728f878349',
-			'org.briarproject:jtorctl:0.3:jtorctl-0.3.jar:f2939238a097898998432effe93b0334d97a787972ab3a91a8973a1d309fc864',
-			'org.briarproject:tor-android:0.2.9.16:tor-android-0.2.9.16.zip:515e33dda6a30853c885a2de2c79ae1ab9ad8b6db44f5db8890333ec2e24f4ae',
-			'org.codehaus.groovy:groovy-all:2.4.12:groovy-all-2.4.12.jar:6a56af4bd48903d56bec62821876cadefafd007360cc6bd0d8f7aa8d72b38be4',
-			'org.codehaus.mojo:animal-sniffer-annotations:1.14:animal-sniffer-annotations-1.14.jar:2068320bd6bad744c3673ab048f67e30bef8f518996fa380033556600669905d',
-			'org.glassfish.jaxb:jaxb-core:2.2.11:jaxb-core-2.2.11.jar:37bcaee8ebb04362c8352a5bf6221b86967ecdab5164c696b10b9a2bb587b2aa',
-			'org.glassfish.jaxb:jaxb-runtime:2.2.11:jaxb-runtime-2.2.11.jar:a874f2351cfba8e2946be3002d10c18a6da8f21b52ba2acf52f2b85d5520ed70',
-			'org.glassfish.jaxb:txw2:2.2.11:txw2-2.2.11.jar:272a3ccad45a4511351920cd2a8633c53cab8d5220c7a92954da5526bb5eafea',
-			'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
-			'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
-			'org.jetbrains.kotlin:kotlin-reflect:1.2.0:kotlin-reflect-1.2.0.jar:4f48a872bad6e4d9c053f4ad610d11e4012ad7e58dc19a03dd5eb811f36069dd',
-			'org.jetbrains.kotlin:kotlin-stdlib-jre7:1.2.0:kotlin-stdlib-jre7-1.2.0.jar:c7a20fb951d437797afe8980aff6c1e5a03f310c661ba58ba1d4fa90cb0f2926',
-			'org.jetbrains.kotlin:kotlin-stdlib-jre8:1.2.0:kotlin-stdlib-jre8-1.2.0.jar:633524eee6ef1941f7cb1dab7ee3927b0a221ceee9047aeb5515f4cbb990c82a',
-			'org.jetbrains.kotlin:kotlin-stdlib:1.2.0:kotlin-stdlib-1.2.0.jar:05cfd9f5ac0b41910703a8925f7211a495909b27a2ffdd1c5106f1689aeafcd4',
-			'org.jetbrains.trove4j:trove4j:20160824:trove4j-20160824.jar:1917871c8deb468307a584680c87a44572f5a8b0b98c6d397fc0f5f86596dbe7',
-			'org.jetbrains:annotations:13.0:annotations-13.0.jar:ace2a10dc8e2d5fd34925ecac03e4988b2c0f851650c94b8cef49ba1bd111478',
-			'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',
-			'org.jmock:jmock-legacy:2.8.2:jmock-legacy-2.8.2.jar:f2b985a5c08a9edb7f37612330c058809da3f6a6d63ce792426ebf8ff0d6d31b',
-			'org.jmock:jmock-testjar:2.8.2:jmock-testjar-2.8.2.jar:8900860f72c474e027cf97fe78dcbf154a1aa7fc62b6845c5fb4e4f3c7bc8760',
-			'org.jmock:jmock:2.8.2:jmock-2.8.2.jar:6c73cb4a2e6dbfb61fd99c9a768539c170ab6568e57846bd60dbf19596b65b16',
-			'org.jvnet.staxex:stax-ex:1.7.7:stax-ex-1.7.7.jar:a31ff7d77163c0deb09e7fee59ad35ae44c2cee2cc8552a116ccd1583d813fb4',
-			'org.objenesis:objenesis:2.1:objenesis-2.1.jar:c74330cc6b806c804fd37e74487b4fe5d7c2750c5e15fbc6efa13bdee1bdef80',
-			'org.ow2.asm:asm-analysis:5.1:asm-analysis-5.1.jar:a34658f5c5de4b573eef21131cc32cc25f7b66407944f312b28ec2e56abb1fa9',
-			'org.ow2.asm:asm-commons:5.1:asm-commons-5.1.jar:97b3786e1f55e74bddf8ad102bf50e33bbcbc1f6b7fd7b36f0bbbb25cd4981be',
-			'org.ow2.asm:asm-tree:5.1:asm-tree-5.1.jar:c0de2bbc4cb8297419659813ecd4ed1d077ed1dd5c1f5544cc5143e493e84c10',
-			'org.ow2.asm:asm-util:5.1:asm-util-5.1.jar:ee032c39ae5e3cd099148fbba9a2124f9ed613e5cb93e03ee0fa8808ce364040',
-			'org.ow2.asm:asm:5.0.4:asm-5.0.4.jar:896618ed8ae62702521a78bc7be42b7c491a08e6920a15f89a3ecdec31e9a220',
-			'org.ow2.asm:asm:5.1:asm-5.1.jar:d2da399a9967c69f0a21739256fa79d284222c223082cacadc17372244764b54',
-	]
+def torBinariesDir = 'src/main/res/raw'
+
+task cleanTorBinaries {
+	doLast {
+		delete fileTree(torBinariesDir) { include '*.zip' }
+	}
 }

-project.afterEvaluate {
+clean.dependsOn cleanTorBinaries
+
+task unpackTorBinaries {
+	doLast {
 		copy {
 			from configurations.tor.collect { zipTree(it) }
-		into 'src/main/res/raw'
+			into torBinariesDir
 		}
 	}
+	dependsOn cleanTorBinaries
+}
+
+tasks.withType(MergeResources) {
+	inputs.dir torBinariesDir
+	dependsOn unpackTorBinaries
+}
@@ -1,129 +0,0 @@
-package org.briarproject.bramble.plugin.tor;
-
-import android.content.Context;
-import android.support.test.runner.AndroidJUnit4;
-
-import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.network.NetworkManager;
-import org.briarproject.bramble.api.plugin.BackoffFactory;
-import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
-import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.bramble.api.system.LocationUtils;
-import org.briarproject.bramble.test.BrambleAndroidIntegrationTestComponent;
-import org.briarproject.bramble.test.BrambleTestCase;
-import org.briarproject.bramble.test.DaggerBrambleAndroidIntegrationTestComponent;
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-import java.util.List;
-import java.util.concurrent.Executor;
-import java.util.concurrent.Executors;
-import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.ScheduledThreadPoolExecutor;
-import java.util.logging.Logger;
-
-import javax.inject.Inject;
-import javax.net.SocketFactory;
-
-import static android.support.test.InstrumentationRegistry.getTargetContext;
-import static java.util.Collections.singletonList;
-import static java.util.concurrent.TimeUnit.SECONDS;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
-
-
-@RunWith(AndroidJUnit4.class)
-public class BridgeTest extends BrambleTestCase {
-
-	private final static long TIMEOUT = SECONDS.toMillis(23);
-
-	private final static Logger LOG =
-			Logger.getLogger(BridgeTest.class.getSimpleName());
-
-	@Inject
-	NetworkManager networkManager;
-	@Inject
-	EventBus eventBus;
-	@Inject
-	BackoffFactory backoffFactory;
-	@Inject
-	Clock clock;
-
-	private final Context appContext = getTargetContext();
-	private final CircumventionProvider circumventionProvider;
-	private final List<String> bridges;
-	private TorPluginFactory factory;
-	private volatile int currentBridge = 0;
-
-	public BridgeTest() {
-		super();
-		circumventionProvider = new CircumventionProvider() {
-			@Override
-			public boolean isTorProbablyBlocked(String countryCode) {
-				return true;
-			}
-
-			@Override
-			public boolean doBridgesWork(String countryCode) {
-				return true;
-			}
-
-			@Override
-			public List<String> getBridges() {
-				return singletonList(bridges.get(currentBridge));
-			}
-		};
-		bridges = new CircumventionProviderImpl(appContext).getBridges();
-	}
-
-	@Before
-	public void setUp() {
-		BrambleAndroidIntegrationTestComponent component =
-				DaggerBrambleAndroidIntegrationTestComponent.builder().build();
-		component.inject(this);
-
-		Executor ioExecutor = Executors.newCachedThreadPool();
-		ScheduledExecutorService scheduler = new ScheduledThreadPoolExecutor(1);
-		LocationUtils locationUtils = () -> "US";
-		SocketFactory torSocketFactory = SocketFactory.getDefault();
-
-		factory = new TorPluginFactory(ioExecutor, scheduler, appContext,
-				networkManager, locationUtils, eventBus, torSocketFactory,
-				backoffFactory, circumventionProvider, clock);
-	}
-
-	@Test
-	public void testBridges() throws Exception {
-		assertTrue(bridges.size() > 0);
-
-		for (int i = 0; i < bridges.size(); i++) {
-			testBridge(i);
-		}
-	}
-
-	private void testBridge(int bridge) throws Exception {
-		DuplexPlugin duplexPlugin =
-				factory.createPlugin(new TorPluginCallBack());
-		assertNotNull(duplexPlugin);
-		TorPlugin plugin = (TorPlugin) duplexPlugin;
-
-		currentBridge = bridge;
-		LOG.warning("Testing " + bridges.get(currentBridge));
-		try {
-			plugin.start();
-			long start = clock.currentTimeMillis();
-			while (clock.currentTimeMillis() - start < TIMEOUT) {
-				if (plugin.isRunning()) return;
-				clock.sleep(500);
-			}
-			if (!plugin.isRunning()) {
-				fail("Could not connect to Tor within timeout.");
-			}
-		} finally {
-			plugin.stop();
-		}
-	}
-
-}
@@ -1,20 +0,0 @@
-package org.briarproject.bramble.test;
-
-import android.app.Application;
-import android.support.test.InstrumentationRegistry;
-
-import javax.inject.Singleton;
-
-import dagger.Module;
-import dagger.Provides;
-
-@Module
-class ApplicationModule {
-
-	@Provides
-	@Singleton
-	Application provideApplication() {
-		return (Application) InstrumentationRegistry.getTargetContext()
-						.getApplicationContext();
-	}
-}
@@ -0,0 +1,11 @@
+package org.briarproject.bramble;
+
+import org.briarproject.bramble.battery.AndroidBatteryModule;
+import org.briarproject.bramble.network.AndroidNetworkModule;
+
+public interface BrambleAndroidEagerSingletons {
+
+	void inject(AndroidBatteryModule.EagerSingletons init);
+
+	void inject(AndroidNetworkModule.EagerSingletons init);
+}
@@ -1,27 +1,22 @@
 package org.briarproject.bramble;

-import android.app.Application;
-
+import org.briarproject.bramble.battery.AndroidBatteryModule;
 import org.briarproject.bramble.network.AndroidNetworkModule;
-import org.briarproject.bramble.plugin.tor.CircumventionProvider;
-import org.briarproject.bramble.plugin.tor.CircumventionProviderImpl;
+import org.briarproject.bramble.plugin.tor.CircumventionModule;
 import org.briarproject.bramble.system.AndroidSystemModule;

-import javax.inject.Singleton;
-
 import dagger.Module;
-import dagger.Provides;

@Module(includes = {
+		AndroidBatteryModule.class,
 		AndroidNetworkModule.class,
-		AndroidSystemModule.class
+		AndroidSystemModule.class,
+		CircumventionModule.class
 })
 public class BrambleAndroidModule {

-	@Provides
-	@Singleton
-	CircumventionProvider provideCircumventionProvider(Application app) {
-		return new CircumventionProviderImpl(app.getApplicationContext());
+	public static void initEagerSingletons(BrambleAndroidEagerSingletons c) {
+		c.inject(new AndroidBatteryModule.EagerSingletons());
+		c.inject(new AndroidNetworkModule.EagerSingletons());
 	}
-
 }
@@ -0,0 +1,84 @@
+package org.briarproject.bramble.battery;
+
+import android.app.Application;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+
+import org.briarproject.bramble.api.battery.BatteryManager;
+import org.briarproject.bramble.api.battery.event.BatteryEvent;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.lifecycle.Service;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import static android.content.Intent.ACTION_BATTERY_CHANGED;
+import static android.content.Intent.ACTION_POWER_CONNECTED;
+import static android.content.Intent.ACTION_POWER_DISCONNECTED;
+import static android.os.BatteryManager.BATTERY_STATUS_CHARGING;
+import static android.os.BatteryManager.BATTERY_STATUS_FULL;
+import static android.os.BatteryManager.EXTRA_STATUS;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Logger.getLogger;
+
+class AndroidBatteryManager implements BatteryManager, Service {
+
+	private static final Logger LOG =
+			getLogger(AndroidBatteryManager.class.getName());
+
+	private final Context appContext;
+	private final EventBus eventBus;
+	private final AtomicBoolean used = new AtomicBoolean(false);
+
+	private volatile BroadcastReceiver batteryReceiver = null;
+
+	@Inject
+	AndroidBatteryManager(Application app, EventBus eventBus) {
+		this.appContext = app.getApplicationContext();
+		this.eventBus = eventBus;
+	}
+
+	@Override
+	public boolean isCharging() {
+		// Get the sticky intent for ACTION_BATTERY_CHANGED
+		IntentFilter filter = new IntentFilter(ACTION_BATTERY_CHANGED);
+		Intent i = appContext.registerReceiver(null, filter);
+		if (i == null) return false;
+		int status = i.getIntExtra(EXTRA_STATUS, -1);
+		return status == BATTERY_STATUS_CHARGING ||
+				status == BATTERY_STATUS_FULL;
+	}
+
+	@Override
+	public void startService() {
+		if (used.getAndSet(true)) throw new IllegalStateException();
+		batteryReceiver = new BatteryReceiver();
+		IntentFilter filter = new IntentFilter();
+		filter.addAction(ACTION_POWER_CONNECTED);
+		filter.addAction(ACTION_POWER_DISCONNECTED);
+		appContext.registerReceiver(batteryReceiver, filter);
+	}
+
+	@Override
+	public void stopService() {
+		if (batteryReceiver != null)
+			appContext.unregisterReceiver(batteryReceiver);
+	}
+
+	private class BatteryReceiver extends BroadcastReceiver {
+
+		@Override
+		public void onReceive(Context ctx, Intent i) {
+			String action = i.getAction();
+			if (LOG.isLoggable(INFO)) LOG.info("Received broadcast " + action);
+			if (ACTION_POWER_CONNECTED.equals(action))
+				eventBus.broadcast(new BatteryEvent(true));
+			else if (ACTION_POWER_DISCONNECTED.equals(action))
+				eventBus.broadcast(new BatteryEvent(false));
+		}
+	}
+}
@@ -0,0 +1,27 @@
+package org.briarproject.bramble.battery;
+
+import org.briarproject.bramble.api.battery.BatteryManager;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class AndroidBatteryModule {
+
+	public static class EagerSingletons {
+		@Inject
+		BatteryManager batteryManager;
+	}
+
+	@Provides
+	@Singleton
+	BatteryManager provideBatteryManager(LifecycleManager lifecycleManager,
+			AndroidBatteryManager batteryManager) {
+		lifecycleManager.registerService(batteryManager);
+		return batteryManager;
+	}
+}
@@ -91,7 +91,7 @@ class AndroidNetworkManager implements NetworkManager, Service {
 	public NetworkStatus getNetworkStatus() {
 		ConnectivityManager cm = (ConnectivityManager)
 				appContext.getSystemService(CONNECTIVITY_SERVICE);
-		assert cm != null;
+		if (cm == null) throw new AssertionError();
 		NetworkInfo net = cm.getActiveNetworkInfo();
 		boolean connected = net != null && net.isConnected();
 		boolean wifi = connected && net.getType() == TYPE_WIFI;
@@ -3,6 +3,7 @@ package org.briarproject.bramble.network;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.network.NetworkManager;

+import javax.inject.Inject;
 import javax.inject.Singleton;

 import dagger.Module;
@@ -11,6 +12,11 @@ import dagger.Provides;
@Module
 public class AndroidNetworkModule {

+	public static class EagerSingletons {
+		@Inject
+		NetworkManager networkManager;
+	}
+
 	@Provides
 	@Singleton
 	NetworkManager provideNetworkManager(LifecycleManager lifecycleManager,
@@ -16,18 +16,27 @@ import org.briarproject.bramble.api.plugin.PluginException;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.util.AndroidUtils;

 import java.io.Closeable;
 import java.io.IOException;
 import java.security.SecureRandom;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
 import java.util.UUID;
+import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Executor;
+import java.util.concurrent.LinkedBlockingQueue;
 import java.util.logging.Logger;

 import javax.annotation.Nullable;

+import static android.bluetooth.BluetoothAdapter.ACTION_DISCOVERY_FINISHED;
+import static android.bluetooth.BluetoothAdapter.ACTION_DISCOVERY_STARTED;
 import static android.bluetooth.BluetoothAdapter.ACTION_SCAN_MODE_CHANGED;
 import static android.bluetooth.BluetoothAdapter.ACTION_STATE_CHANGED;
 import static android.bluetooth.BluetoothAdapter.EXTRA_SCAN_MODE;
@@ -37,8 +46,13 @@ import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERA
 import static android.bluetooth.BluetoothAdapter.SCAN_MODE_NONE;
 import static android.bluetooth.BluetoothAdapter.STATE_OFF;
 import static android.bluetooth.BluetoothAdapter.STATE_ON;
+import static android.bluetooth.BluetoothDevice.ACTION_FOUND;
+import static android.bluetooth.BluetoothDevice.EXTRA_DEVICE;
+import static java.util.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;
+import static org.briarproject.bramble.util.PrivacyUtils.scrubMacAddress;

@MethodsNotNullByDefault
@ParametersNotNullByDefault
@@ -47,8 +61,11 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 	private static final Logger LOG =
 			Logger.getLogger(AndroidBluetoothPlugin.class.getName());

+	private static final int MAX_DISCOVERY_MS = 10_000;
+
 	private final AndroidExecutor androidExecutor;
 	private final Context appContext;
+	private final Clock clock;

 	private volatile boolean wasEnabledByUs = false;
 	private volatile BluetoothStateReceiver receiver = null;
@@ -58,12 +75,13 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {

 	AndroidBluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
 			Executor ioExecutor, AndroidExecutor androidExecutor,
-			Context appContext, SecureRandom secureRandom, Backoff backoff,
-			DuplexPluginCallback callback, int maxLatency) {
+			Context appContext, SecureRandom secureRandom, Clock clock,
+			Backoff backoff, DuplexPluginCallback callback, int maxLatency) {
 		super(connectionLimiter, ioExecutor, secureRandom, backoff, callback,
 				maxLatency);
 		this.androidExecutor = androidExecutor;
 		this.appContext = appContext;
+		this.clock = clock;
 	}

 	@Override
@@ -182,6 +200,74 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 		}
 	}

+	@Override
+	@Nullable
+	DuplexTransportConnection discoverAndConnect(String uuid) {
+		if (adapter == null) return null;
+		for (String address : discoverDevices()) {
+			try {
+				if (LOG.isLoggable(INFO))
+					LOG.info("Connecting to " + scrubMacAddress(address));
+				return connectTo(address, uuid);
+			} catch (IOException e) {
+				if (LOG.isLoggable(INFO)) {
+					LOG.info("Could not connect to "
+							+ scrubMacAddress(address));
+				}
+			}
+		}
+		LOG.info("Could not connect to any devices");
+		return null;
+	}
+
+	private Collection<String> discoverDevices() {
+		List<String> addresses = new ArrayList<>();
+		BlockingQueue<Intent> intents = new LinkedBlockingQueue<>();
+		DiscoveryReceiver receiver = new DiscoveryReceiver(intents);
+		IntentFilter filter = new IntentFilter();
+		filter.addAction(ACTION_DISCOVERY_STARTED);
+		filter.addAction(ACTION_DISCOVERY_FINISHED);
+		filter.addAction(ACTION_FOUND);
+		appContext.registerReceiver(receiver, filter);
+		try {
+			if (adapter.startDiscovery()) {
+				long now = clock.currentTimeMillis();
+				long end = now + MAX_DISCOVERY_MS;
+				while (now < end) {
+					Intent i = intents.poll(end - now, MILLISECONDS);
+					if (i == null) break;
+					String action = i.getAction();
+					if (ACTION_DISCOVERY_STARTED.equals(action)) {
+						LOG.info("Discovery started");
+					} else if (ACTION_DISCOVERY_FINISHED.equals(action)) {
+						LOG.info("Discovery finished");
+						break;
+					} else if (ACTION_FOUND.equals(action)) {
+						BluetoothDevice d = i.getParcelableExtra(EXTRA_DEVICE);
+						String address = d.getAddress();
+						if (LOG.isLoggable(INFO))
+							LOG.info("Discovered " + scrubMacAddress(address));
+						if (!addresses.contains(address))
+							addresses.add(address);
+					}
+					now = clock.currentTimeMillis();
+				}
+			} else {
+				LOG.info("Could not start discovery");
+			}
+		} catch (InterruptedException e) {
+			LOG.info("Interrupted while discovering devices");
+			Thread.currentThread().interrupt();
+		} finally {
+			LOG.info("Cancelling discovery");
+			adapter.cancelDiscovery();
+			appContext.unregisterReceiver(receiver);
+		}
+		// Shuffle the addresses so we don't always try the same one first
+		Collections.shuffle(addresses);
+		return addresses;
+	}
+
 	private void tryToClose(@Nullable Closeable c) {
 		try {
 			if (c != null) c.close();
@@ -207,4 +293,18 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 			}
 		}
 	}
+
+	private static class DiscoveryReceiver extends BroadcastReceiver {
+
+		private final BlockingQueue<Intent> intents;
+
+		private DiscoveryReceiver(BlockingQueue<Intent> intents) {
+			this.intents = intents;
+		}
+
+		@Override
+		public void onReceive(Context ctx, Intent intent) {
+			intents.add(intent);
+		}
+	}
 }
@@ -11,6 +11,7 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
 import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.bramble.api.system.Clock;

 import java.security.SecureRandom;
 import java.util.concurrent.Executor;
@@ -33,17 +34,19 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 	private final Context appContext;
 	private final SecureRandom secureRandom;
 	private final EventBus eventBus;
+	private final Clock clock;
 	private final BackoffFactory backoffFactory;

 	public AndroidBluetoothPluginFactory(Executor ioExecutor,
 			AndroidExecutor androidExecutor, Context appContext,
-			SecureRandom secureRandom, EventBus eventBus,
+			SecureRandom secureRandom, EventBus eventBus, Clock clock,
 			BackoffFactory backoffFactory) {
 		this.ioExecutor = ioExecutor;
 		this.androidExecutor = androidExecutor;
 		this.appContext = appContext;
 		this.secureRandom = secureRandom;
 		this.eventBus = eventBus;
+		this.clock = clock;
 		this.backoffFactory = backoffFactory;
 	}

@@ -65,7 +68,7 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		AndroidBluetoothPlugin plugin = new AndroidBluetoothPlugin(
 				connectionLimiter, ioExecutor, androidExecutor, appContext,
-				secureRandom, backoff, callback, MAX_LATENCY);
+				secureRandom, clock, backoff, callback, MAX_LATENCY);
 		eventBus.addListener(plugin);
 		return plugin;
 	}
@@ -68,7 +68,7 @@ class AndroidLanTcpPlugin extends LanTcpPlugin implements EventListener {
 				new PoliteExecutor("AndroidLanTcpPlugin", ioExecutor, 1);
 		ConnectivityManager connectivityManager = (ConnectivityManager)
 				appContext.getSystemService(CONNECTIVITY_SERVICE);
-		assert connectivityManager != null;
+		if (connectivityManager == null) throw new AssertionError();
 		this.connectivityManager = connectivityManager;
 		wifiManager = (WifiManager) appContext.getApplicationContext()
 				.getSystemService(WIFI_SERVICE);
@@ -0,0 +1,90 @@
+package org.briarproject.bramble.plugin.tor;
+
+import android.content.Context;
+import android.content.pm.PackageInfo;
+import android.content.pm.PackageManager;
+import android.content.pm.PackageManager.NameNotFoundException;
+import android.os.PowerManager;
+
+import org.briarproject.bramble.api.battery.BatteryManager;
+import org.briarproject.bramble.api.network.NetworkManager;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.bramble.api.plugin.Backoff;
+import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.system.LocationUtils;
+import org.briarproject.bramble.api.system.ResourceProvider;
+import org.briarproject.bramble.util.RenewableWakeLock;
+
+import java.io.IOException;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ScheduledExecutorService;
+
+import javax.net.SocketFactory;
+
+import static android.content.Context.MODE_PRIVATE;
+import static android.content.Context.POWER_SERVICE;
+import static android.os.PowerManager.PARTIAL_WAKE_LOCK;
+import static java.util.concurrent.TimeUnit.MINUTES;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+class AndroidTorPlugin extends TorPlugin {
+
+	// This tag may prevent Huawei's power manager from killing us
+	private static final String WAKE_LOCK_TAG = "LocationManagerService";
+
+	private final Context appContext;
+	private final RenewableWakeLock wakeLock;
+
+	AndroidTorPlugin(Executor ioExecutor, ScheduledExecutorService scheduler,
+			Context appContext, NetworkManager networkManager,
+			LocationUtils locationUtils, SocketFactory torSocketFactory,
+			Clock clock, ResourceProvider resourceProvider,
+			CircumventionProvider circumventionProvider,
+			BatteryManager batteryManager, Backoff backoff,
+			DuplexPluginCallback callback, String architecture, int maxLatency,
+			int maxIdleTime) {
+		super(ioExecutor, networkManager, locationUtils, torSocketFactory,
+				clock, resourceProvider, circumventionProvider, batteryManager,
+				backoff, callback, architecture, maxLatency, maxIdleTime,
+				appContext.getDir("tor", MODE_PRIVATE));
+		this.appContext = appContext;
+		PowerManager pm = (PowerManager)
+				appContext.getSystemService(POWER_SERVICE);
+		if (pm == null) throw new AssertionError();
+		wakeLock = new RenewableWakeLock(pm, scheduler, PARTIAL_WAKE_LOCK,
+				WAKE_LOCK_TAG, 1, MINUTES);
+	}
+
+	@Override
+	protected int getProcessId() {
+		return android.os.Process.myPid();
+	}
+
+	@Override
+	protected long getLastUpdateTime() {
+		try {
+			PackageManager pm = appContext.getPackageManager();
+			PackageInfo pi = pm.getPackageInfo(appContext.getPackageName(), 0);
+			return pi.lastUpdateTime;
+		} catch (NameNotFoundException e) {
+			throw new AssertionError(e);
+		}
+	}
+
+	@Override
+	protected void enableNetwork(boolean enable) throws IOException {
+		if (!running) return;
+		if (enable) wakeLock.acquire();
+		super.enableNetwork(enable);
+		if (!enable) wakeLock.release();
+	}
+
+	@Override
+	public void stop() {
+		super.stop();
+		wakeLock.release();
+	}
+}
@@ -3,6 +3,7 @@ package org.briarproject.bramble.plugin.tor;
 import android.content.Context;
 import android.os.Build;

+import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
@@ -15,6 +16,7 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
+import org.briarproject.bramble.api.system.ResourceProvider;
 import org.briarproject.bramble.util.AndroidUtils;

 import java.util.concurrent.Executor;
@@ -26,10 +28,10 @@ import javax.net.SocketFactory;

@Immutable
@NotNullByDefault
-public class TorPluginFactory implements DuplexPluginFactory {
+public class AndroidTorPluginFactory implements DuplexPluginFactory {

 	private static final Logger LOG =
-			Logger.getLogger(TorPluginFactory.class.getName());
+			Logger.getLogger(AndroidTorPluginFactory.class.getName());

 	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
 	private static final int MAX_IDLE_TIME = 30 * 1000; // 30 seconds
@@ -45,15 +47,18 @@ public class TorPluginFactory implements DuplexPluginFactory {
 	private final EventBus eventBus;
 	private final SocketFactory torSocketFactory;
 	private final BackoffFactory backoffFactory;
+	private final ResourceProvider resourceProvider;
 	private final CircumventionProvider circumventionProvider;
+	private final BatteryManager batteryManager;
 	private final Clock clock;

-	public TorPluginFactory(Executor ioExecutor,
+	public AndroidTorPluginFactory(Executor ioExecutor,
 			ScheduledExecutorService scheduler, Context appContext,
 			NetworkManager networkManager, LocationUtils locationUtils,
 			EventBus eventBus, SocketFactory torSocketFactory,
-			BackoffFactory backoffFactory,
-			CircumventionProvider circumventionProvider, Clock clock) {
+			BackoffFactory backoffFactory, ResourceProvider resourceProvider,
+			CircumventionProvider circumventionProvider,
+			BatteryManager batteryManager, Clock clock) {
 		this.ioExecutor = ioExecutor;
 		this.scheduler = scheduler;
 		this.appContext = appContext;
@@ -62,7 +67,9 @@ public class TorPluginFactory implements DuplexPluginFactory {
 		this.eventBus = eventBus;
 		this.torSocketFactory = torSocketFactory;
 		this.backoffFactory = backoffFactory;
+		this.resourceProvider = resourceProvider;
 		this.circumventionProvider = circumventionProvider;
+		this.batteryManager = batteryManager;
 		this.clock = clock;
 	}

@@ -99,10 +106,10 @@ public class TorPluginFactory implements DuplexPluginFactory {

 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		TorPlugin plugin = new TorPlugin(ioExecutor, scheduler, appContext,
-				networkManager, locationUtils, torSocketFactory, clock,
-				circumventionProvider, backoff, callback, architecture,
-				MAX_LATENCY, MAX_IDLE_TIME);
+		AndroidTorPlugin plugin = new AndroidTorPlugin(ioExecutor, scheduler,
+				appContext, networkManager, locationUtils, torSocketFactory,
+				clock, resourceProvider, circumventionProvider, batteryManager,
+				backoff, callback, architecture, MAX_LATENCY, MAX_IDLE_TIME);
 		eventBus.addListener(plugin);
 		return plugin;
 	}
@@ -0,0 +1,32 @@
+package org.briarproject.bramble.system;
+
+import android.app.Application;
+import android.content.Context;
+import android.content.res.Resources;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.ResourceProvider;
+
+import java.io.InputStream;
+
+import javax.inject.Inject;
+
+@NotNullByDefault
+class AndroidResourceProvider implements ResourceProvider {
+
+	private final Context appContext;
+
+	@Inject
+	AndroidResourceProvider(Application app) {
+		this.appContext = app.getApplicationContext();
+	}
+
+	@Override
+	public InputStream getResourceInputStream(String name, String extension) {
+		Resources res = appContext.getResources();
+		// extension is ignored on Android, resources are retrieved without it
+		int resId =
+				res.getIdentifier(name, "raw", appContext.getPackageName());
+		return res.openRawResource(resId);
+	}
+}
@@ -1,9 +1,8 @@
 package org.briarproject.bramble.system;

-import android.app.Application;
-
 import org.briarproject.bramble.api.system.AndroidExecutor;
 import org.briarproject.bramble.api.system.LocationUtils;
+import org.briarproject.bramble.api.system.ResourceProvider;
 import org.briarproject.bramble.api.system.SecureRandomProvider;

 import javax.inject.Singleton;
@@ -16,18 +15,26 @@ public class AndroidSystemModule {

 	@Provides
 	@Singleton
-	SecureRandomProvider provideSecureRandomProvider(Application app) {
-		return new AndroidSecureRandomProvider(app);
+	SecureRandomProvider provideSecureRandomProvider(
+			AndroidSecureRandomProvider provider) {
+		return provider;
 	}

 	@Provides
-	LocationUtils provideLocationUtils(Application app) {
-		return new AndroidLocationUtils(app);
+	LocationUtils provideLocationUtils(AndroidLocationUtils locationUtils) {
+		return locationUtils;
 	}

 	@Provides
 	@Singleton
-	AndroidExecutor provideAndroidExecutor(Application app) {
-		return new AndroidExecutorImpl(app);
+	AndroidExecutor provideAndroidExecutor(
+			AndroidExecutorImpl androidExecutor) {
+		return androidExecutor;
+	}
+
+	@Provides
+	@Singleton
+	ResourceProvider provideResourceProvider(AndroidResourceProvider provider) {
+		return provider;
 	}
 }
@@ -11,15 +11,12 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
-import java.util.logging.Logger;

 import static android.content.Context.MODE_PRIVATE;
+import static android.os.Build.VERSION.SDK_INT;

 public class AndroidUtils {

-	private static final Logger LOG =
-			Logger.getLogger(AndroidUtils.class.getName());
-
 	// Fake Bluetooth address returned by BluetoothAdapter on API 23 and later
 	private static final String FAKE_BLUETOOTH_ADDRESS = "02:00:00:00:00:00";

@@ -28,7 +25,7 @@ public class AndroidUtils {
 	@SuppressWarnings("deprecation")
 	public static Collection<String> getSupportedArchitectures() {
 		List<String> abis = new ArrayList<>();
-		if (Build.VERSION.SDK_INT >= 21) {
+		if (SDK_INT >= 21) {
 			abis.addAll(Arrays.asList(Build.SUPPORTED_ABIS));
 		} else {
 			abis.add(Build.CPU_ABI);
@@ -1,8 +0,0 @@
-Bridge 131.252.210.150:8081 0E858AC201BF0F3FA3C462F64844CBFFC7297A42
-Bridge 67.205.189.122:8443 12D64D5D44E20169585E7378580C0D33A872AD98
-Bridge 45.32.148.146:8443 0CE016FB2462D8BF179AE71F7D702D09DEAC3F1D
-Bridge 148.251.90.59:7510 019F727CA6DCA6CA5C90B55E477B7D87981E75BC
-Bridge 195.91.239.8:9001 BA83F62551545655BBEBBFF353A45438D73FD45A
-Bridge 185.165.184.217:6429 64CC94BEC51254E4409AD059192833854CCB95F0
-Bridge 45.55.1.74:8443 6F18FEFBB0CAECD5ABA755312FCCB34FC11A7AB8
-Bridge 95.85.40.163:9001 40057BE9CF76B6C5BDBE713753468BE0A990DE9C
@@ -0,0 +1,101 @@
+dependencyVerification {
+    verify = [
+        'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
+        'com.android.tools.analytics-library:protos:26.2.1:protos-26.2.1.jar:2f371f5b1f551e85ab08be4d6a2873471b3d44afd1ebf6aa3298f3b796bf691f',
+        'com.android.tools.analytics-library:shared:26.2.1:shared-26.2.1.jar:4c1e4e705fa4d45f23aaea230557f6508155012d9c296337787c1d7b26a97f5a',
+        'com.android.tools.analytics-library:tracker:26.2.1:tracker-26.2.1.jar:4a624ecc976539f755ddb0bb8dfc2dd3d08326cfec59a098dbd70f701ca7fb75',
+        'com.android.tools.build:aapt2:3.2.1-4818971:aapt2-3.2.1-4818971-linux.jar:f431b6f96c91a2c155144b091a9c97d9805c589fe8efc9c930b6cd346cb60a1e',
+        'com.android.tools.build:apksig:3.2.1:apksig-3.2.1.jar:2b46f2feffea66037aab29e4261b2433c190194a6ef97b958511eb157f2ccba5',
+        'com.android.tools.build:apkzlib:3.2.1:apkzlib-3.2.1.jar:c39ad0313905932431fe81c8899c2cf39a4d92ad6c4edcaa4b25432f461452aa',
+        'com.android.tools.build:builder-model:3.2.1:builder-model-3.2.1.jar:a9f68e6abcec122f9cb5ad352d3f05a3eb03acbcdca95e4d25c16310c2c965ff',
+        'com.android.tools.build:builder-test-api:3.2.1:builder-test-api-3.2.1.jar:533ac6c2b5884bb54967a33791f2628dfdfac7981af39417a333b43d4379b6be',
+        'com.android.tools.build:builder:3.2.1:builder-3.2.1.jar:aedcbfd115dbe91d09b4113e66ef50589b558d0aa3b2f133b1d867c9b87fae83',
+        'com.android.tools.build:gradle-api:3.2.1:gradle-api-3.2.1.jar:57cf0ac5ac1dca8afdb3f62b94265e776e7dcfa641cc3844fb53a05193de208d',
+        'com.android.tools.build:manifest-merger:26.2.1:manifest-merger-26.2.1.jar:8830573263361035d38cfdcb51e2db94029c93865b21334f5fbf8a27984281a6',
+        'com.android.tools.ddms:ddmlib:26.2.1:ddmlib-26.2.1.jar:a4bf0a29a19980bf27269465cc782064656750b77c26728f82f9e148b705218b',
+        'com.android.tools.external.com-intellij:intellij-core:26.2.1:intellij-core-26.2.1.jar:4925ad1892c2687cb1a63427d440ef519c8c59215fefe0dc5d541d5d411fcafe',
+        'com.android.tools.external.com-intellij:kotlin-compiler:26.2.1:kotlin-compiler-26.2.1.jar:daa064fd708f340ee25fb9823c4c74104ac77f1370b76d907eb9ae6daec0a2ae',
+        'com.android.tools.external.org-jetbrains:uast:26.2.1:uast-26.2.1.jar:f10f7258d2ab9189562cc0f9ad838c0378fdba439229173390a99de02ebac75b',
+        'com.android.tools.layoutlib:layoutlib-api:26.2.1:layoutlib-api-26.2.1.jar:ddbf4fca123733fa011595b1cc1f4ac2937ed327b60990711fafc33c775c2ade',
+        'com.android.tools.lint:lint-api:26.2.1:lint-api-26.2.1.jar:3b57e739de567b98bc9ab56c2c0ee66fc026b4adf5843e8f9804ca0666a6f66e',
+        'com.android.tools.lint:lint-checks:26.2.1:lint-checks-26.2.1.jar:c86f4cc9aaee722ee4ad70062f7b5af91e9b041914af27adc09f545ab0fb3bc6',
+        'com.android.tools.lint:lint-gradle-api:26.2.1:lint-gradle-api-26.2.1.jar:2283e7af32e301565f2a797e531f0fc8c648077d457afb3ffdddbee638976c2f',
+        'com.android.tools.lint:lint-gradle:26.2.1:lint-gradle-26.2.1.jar:8fd90b2f3ec788cbb9801c07ab3e1ea2255aa31a6093157d7ea0ff13d0315ecb',
+        'com.android.tools.lint:lint-kotlin:26.2.1:lint-kotlin-26.2.1.jar:7a6a5d2b18f69cf1b900d857c2632b4c683713c533295933b8b759f8cab4a877',
+        'com.android.tools.lint:lint:26.2.1:lint-26.2.1.jar:7848b82ae988b90dee259ae7c7e86e05cbf52db6cd21c8bbd38ce7df08f3f8c5',
+        'com.android.tools:annotations:26.2.1:annotations-26.2.1.jar:7391c6a1e080174b96e64ceb078dadd31ce4d8a2d2fee0ec65be202126f90f24',
+        'com.android.tools:common:26.2.1:common-26.2.1.jar:a50aab2d6411ff68f4004a87c7e93d87d8e980a0ec3b352246549897ea2d78e5',
+        'com.android.tools:dvlib:26.2.1:dvlib-26.2.1.jar:72a83bf2839b1df9b1fbf67ba45d1bfb9f966cd774da4320c762b2be8f1688aa',
+        'com.android.tools:repository:26.2.1:repository-26.2.1.jar:fa74dae09103faef703df38550ad8fa244c5b6d1bf90d6198be932292b3d9cc1',
+        'com.android.tools:sdk-common:26.2.1:sdk-common-26.2.1.jar:759d4b292ca69a35cf961fca377b54158fc6c88108978006999442e80a011cf4',
+        'com.android.tools:sdklib:26.2.1:sdklib-26.2.1.jar:248df7ad5eac4aeb6f96c394c76760de4b7b89ac056e54d0c21a739368b91b45',
+        'com.google.code.findbugs:jsr305:1.3.9:jsr305-1.3.9.jar:905721a0eea90a81534abb7ee6ef4ea2e5e645fa1def0a5cd88402df1b46c9ed',
+        'com.google.code.gson:gson:2.8.0:gson-2.8.0.jar:c6221763bd79c4f1c3dc7f750b5f29a0bb38b367b81314c4f71896e340c40825',
+        'com.google.dagger:dagger-compiler:2.19:dagger-compiler-2.19.jar:27a4b202a2de908182edb261f8c0a264e08e5e4733d7514bc7fbf0d31da5c0fc',
+        'com.google.dagger:dagger-producers:2.19:dagger-producers-2.19.jar:a17663abe0fc38b676026950907d4c5f5e2bf338375415861eaff6e3bdb0b768',
+        'com.google.dagger:dagger-spi:2.19:dagger-spi-2.19.jar:e7a6379d82c841f6aac2866948ad1eed716528707814602842a8d844ce04e2e1',
+        'com.google.dagger:dagger:2.19:dagger-2.19.jar:514b6f1e0727c6572e1d65cb27e4ae668b7aeaeb93a29515182965265b609939',
+        'com.google.errorprone:error_prone_annotations:2.0.18:error_prone_annotations-2.0.18.jar:cb4cfad870bf563a07199f3ebea5763f0dec440fcda0b318640b1feaa788656b',
+        'com.google.errorprone:error_prone_annotations:2.1.3:error_prone_annotations-2.1.3.jar:03d0329547c13da9e17c634d1049ea2ead093925e290567e1a364fd6b1fc7ff8',
+        'com.google.errorprone:javac-shaded:9-dev-r4023-3:javac-shaded-9-dev-r4023-3.jar:65bfccf60986c47fbc17c9ebab0be626afc41741e0a6ec7109e0768817a36f30',
+        'com.google.googlejavaformat:google-java-format:1.5:google-java-format-1.5.jar:aa19ad7850fb85178aa22f2fddb163b84d6ce4d0035872f30d4408195ca1144e',
+        'com.google.guava:guava:23.0:guava-23.0.jar:7baa80df284117e5b945b19b98d367a85ea7b7801bd358ff657946c3bd1b6596',
+        'com.google.guava:guava:25.0-jre:guava-25.0-jre.jar:3fd4341776428c7e0e5c18a7c10de129475b69ab9d30aeafbb5c277bb6074fa9',
+        'com.google.j2objc:j2objc-annotations:1.1:j2objc-annotations-1.1.jar:40ceb7157feb263949e0f503fe5f71689333a621021aa20ce0d0acee3badaa0f',
+        'com.google.jimfs:jimfs:1.1:jimfs-1.1.jar:c4828e28d7c0a930af9387510b3bada7daa5c04d7c25a75c7b8b081f1c257ddd',
+        'com.google.protobuf:protobuf-java:3.4.0:protobuf-java-3.4.0.jar:dce7e66b32456a1b1198da0caff3a8acb71548658391e798c79369241e6490a4',
+        'com.googlecode.json-simple:json-simple:1.1:json-simple-1.1.jar:2d9484f4c649f708f47f9a479465fc729770ee65617dca3011836602264f6439',
+        'com.squareup:javapoet:1.11.1:javapoet-1.11.1.jar:9cbf2107be499ec6e95afd36b58e3ca122a24166cdd375732e51267d64058e90',
+        'com.squareup:javawriter:2.5.0:javawriter-2.5.0.jar:fcfb09fb0ea0aa97d3cfe7ea792398081348e468f126b3603cb3803f240197f0',
+        '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-logging:commons-logging:1.2:commons-logging-1.2.jar:daddea1ea0be0f56978ab3006b8ac92834afeefbd9b7e4e6316fca57df0fa636',
+        'it.unimi.dsi:fastutil:7.2.0:fastutil-7.2.0.jar:74fa208043740642f7e6eb09faba15965218ad2f50ce3020efb100136e4b591c',
+        'javax.annotation:jsr250-api:1.0:jsr250-api-1.0.jar:a1a922d0d9b6d183ed3800dfac01d1e1eb159f0e8c6f94736931c1def54a941f',
+        'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
+        'javax.xml.bind:jaxb-api:2.2.12-b140109.1041:jaxb-api-2.2.12-b140109.1041.jar:b5e60cd8b7b5ff01ce4a74c5dd008f4fbd14ced3495d0b47b85cfedc182211f2',
+        'junit:junit:4.12:junit-4.12.jar:59721f0805e223d84b90677887d9ff567dc534d7c502ca903c0c2b17f05c116a',
+        'net.sf.jopt-simple:jopt-simple:4.9:jopt-simple-4.9.jar:26c5856e954b5f864db76f13b86919b59c6eecf9fd930b96baa8884626baf2f5',
+        'net.sf.kxml:kxml2:2.3.0:kxml2-2.3.0.jar:f264dd9f79a1fde10ce5ecc53221eff24be4c9331c830b7d52f2f08a7b633de2',
+        'org.apache.ant:ant-launcher:1.9.4:ant-launcher-1.9.4.jar:7bccea20b41801ca17bcbc909a78c835d0f443f12d639c77bd6ae3d05861608d',
+        'org.apache.ant:ant:1.9.4:ant-1.9.4.jar:649ae0730251de07b8913f49286d46bba7b92d47c5f332610aa426c4f02161d8',
+        'org.apache.commons:commons-compress:1.12:commons-compress-1.12.jar:2c1542faf343185b7cab9c3d55c8ae5471d6d095d3887a4adefdbdf2984dc0b6',
+        'org.apache.httpcomponents:httpclient:4.5.2: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.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
+        'org.bouncycastle:bcpkix-jdk15on:1.56:bcpkix-jdk15on-1.56.jar:7043dee4e9e7175e93e0b36f45b1ec1ecb893c5f755667e8b916eb8dd201c6ca',
+        'org.bouncycastle:bcprov-jdk15on:1.56:bcprov-jdk15on-1.56.jar:963e1ee14f808ffb99897d848ddcdb28fa91ddda867eb18d303e82728f878349',
+        'org.briarproject:obfs4proxy-android:0.0.7:obfs4proxy-android-0.0.7.zip:abdfb5d889d848de9bf214f9276abbf454808a505b870819eccc9a9e985bf617',
+        'org.briarproject:tor-android:0.3.4.8:tor-android-0.3.4.8.zip:989a0352d9d8d8172cd6c2137654e165e5d2beb10ed1211bab3814e224ad1926',
+        'org.checkerframework:checker-compat-qual:2.5.3:checker-compat-qual-2.5.3.jar:d76b9afea61c7c082908023f0cbc1427fab9abd2df915c8b8a3e7a509bccbc6d',
+        'org.codehaus.groovy:groovy-all:2.4.12:groovy-all-2.4.12.jar:6a56af4bd48903d56bec62821876cadefafd007360cc6bd0d8f7aa8d72b38be4',
+        'org.codehaus.mojo:animal-sniffer-annotations:1.14:animal-sniffer-annotations-1.14.jar:2068320bd6bad744c3673ab048f67e30bef8f518996fa380033556600669905d',
+        'org.glassfish.jaxb:jaxb-core:2.2.11:jaxb-core-2.2.11.jar:37bcaee8ebb04362c8352a5bf6221b86967ecdab5164c696b10b9a2bb587b2aa',
+        'org.glassfish.jaxb:jaxb-runtime:2.2.11:jaxb-runtime-2.2.11.jar:a874f2351cfba8e2946be3002d10c18a6da8f21b52ba2acf52f2b85d5520ed70',
+        'org.glassfish.jaxb:txw2:2.2.11:txw2-2.2.11.jar:272a3ccad45a4511351920cd2a8633c53cab8d5220c7a92954da5526bb5eafea',
+        'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
+        'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
+        'org.jetbrains.kotlin:kotlin-reflect:1.2.0:kotlin-reflect-1.2.0.jar:4f48a872bad6e4d9c053f4ad610d11e4012ad7e58dc19a03dd5eb811f36069dd',
+        'org.jetbrains.kotlin:kotlin-stdlib-common:1.2.71:kotlin-stdlib-common-1.2.71.jar:63999687ff2fce8a592dd180ffbbf8f1d21c26b4044c55cdc74ff3cf3b3cf328',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.2.71:kotlin-stdlib-jdk7-1.2.71.jar:b136bd61b240e07d4d92ce00d3bd1dbf584400a7bf5f220c2f3cd22446858082',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.2.71:kotlin-stdlib-jdk8-1.2.71.jar:ac3c8abf47790b64b4f7e2509a53f0c145e061ac1612a597520535d199946ea9',
+        'org.jetbrains.kotlin:kotlin-stdlib:1.2.71:kotlin-stdlib-1.2.71.jar:4c895c270b87f5fec2a2796e1d89c15407ee821de961527c28588bb46afbc68b',
+        'org.jetbrains.trove4j:trove4j:20160824:trove4j-20160824.jar:1917871c8deb468307a584680c87a44572f5a8b0b98c6d397fc0f5f86596dbe7',
+        'org.jetbrains:annotations:13.0:annotations-13.0.jar:ace2a10dc8e2d5fd34925ecac03e4988b2c0f851650c94b8cef49ba1bd111478',
+        'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',
+        'org.jmock:jmock-legacy:2.8.2:jmock-legacy-2.8.2.jar:f2b985a5c08a9edb7f37612330c058809da3f6a6d63ce792426ebf8ff0d6d31b',
+        'org.jmock:jmock-testjar:2.8.2:jmock-testjar-2.8.2.jar:8900860f72c474e027cf97fe78dcbf154a1aa7fc62b6845c5fb4e4f3c7bc8760',
+        'org.jmock:jmock:2.8.2:jmock-2.8.2.jar:6c73cb4a2e6dbfb61fd99c9a768539c170ab6568e57846bd60dbf19596b65b16',
+        'org.jvnet.staxex:stax-ex:1.7.7:stax-ex-1.7.7.jar:a31ff7d77163c0deb09e7fee59ad35ae44c2cee2cc8552a116ccd1583d813fb4',
+        'org.objenesis:objenesis:2.1:objenesis-2.1.jar:c74330cc6b806c804fd37e74487b4fe5d7c2750c5e15fbc6efa13bdee1bdef80',
+        'org.ow2.asm:asm-analysis:6.0:asm-analysis-6.0.jar:2f1a6387219c3a6cc4856481f221b03bd9f2408a326d416af09af5d6f608c1f4',
+        'org.ow2.asm:asm-commons:6.0:asm-commons-6.0.jar:f1bce5c648a96a017bdcd01fe5d59af9845297fd7b79b81c015a6fbbd9719abf',
+        'org.ow2.asm:asm-tree:6.0:asm-tree-6.0.jar:887998fb69727c8759e4d253f856822801e33f9fd4caa566b3ac58ee92106215',
+        'org.ow2.asm:asm-util:6.0:asm-util-6.0.jar:356afebdb0f870175262e5188f8709a3b17aa2a5a6a4b0340b04d4b449bca5f6',
+        'org.ow2.asm:asm:5.0.4:asm-5.0.4.jar:896618ed8ae62702521a78bc7be42b7c491a08e6920a15f89a3ecdec31e9a220',
+        'org.ow2.asm:asm:6.0:asm-6.0.jar:dd8971c74a4e697899a8e95caae4ea8760ea6c486dc6b97b1795e75760420461',
+    ]
+}
@@ -4,46 +4,20 @@ targetCompatibility = 1.8

 apply plugin: 'ru.vyarus.animalsniffer'
 apply plugin: 'witness'
+apply from: 'witness.gradle'

 dependencies {
-	implementation "com.google.dagger:dagger:2.0.2"
+	implementation "com.google.dagger:dagger:2.19"
 	implementation 'com.google.code.findbugs:jsr305:3.0.2'

 	testImplementation 'junit:junit:4.12'
 	testImplementation "org.jmock:jmock:2.8.2"
 	testImplementation "org.jmock:jmock-junit4:2.8.2"
 	testImplementation "org.jmock:jmock-legacy:2.8.2"
-	testImplementation "org.hamcrest:hamcrest-library:1.3"
-	testImplementation "org.hamcrest:hamcrest-core:1.3"

 	signature 'org.codehaus.mojo.signature:java16:1.1@signature'
 }

-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:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
-			'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',
-			'org.apache.ant:ant:1.9.4:ant-1.9.4.jar:649ae0730251de07b8913f49286d46bba7b92d47c5f332610aa426c4f02161d8',
-			'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
-			'org.codehaus.mojo.signature:java16:1.1:java16-1.1.signature:53799223a2c98dba2d0add810bed76315460df285c69e4f397ae6098f87dd619',
-			'org.codehaus.mojo:animal-sniffer-ant-tasks:1.16:animal-sniffer-ant-tasks-1.16.jar:890040976fbe2d584619a6a61b1fd2e925b3b5eb342a85eb2762c467c0d64e90',
-			'org.codehaus.mojo:animal-sniffer:1.16:animal-sniffer-1.16.jar:72be8bcc226ba43b937c722a08a07852bfa1b11400089265d5df0ee7b38b1d52',
-			'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
-			'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
-			'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',
-			'org.jmock:jmock-legacy:2.8.2:jmock-legacy-2.8.2.jar:f2b985a5c08a9edb7f37612330c058809da3f6a6d63ce792426ebf8ff0d6d31b',
-			'org.jmock:jmock-testjar:2.8.2:jmock-testjar-2.8.2.jar:8900860f72c474e027cf97fe78dcbf154a1aa7fc62b6845c5fb4e4f3c7bc8760',
-			'org.jmock:jmock:2.8.2:jmock-2.8.2.jar:6c73cb4a2e6dbfb61fd99c9a768539c170ab6568e57846bd60dbf19596b65b16',
-			'org.objenesis:objenesis:2.1:objenesis-2.1.jar:c74330cc6b806c804fd37e74487b4fe5d7c2750c5e15fbc6efa13bdee1bdef80',
-			'org.ow2.asm:asm-all:5.2:asm-all-5.2.jar:7fbffbc1db3422e2101689fd88df8384b15817b52b9b2b267b9f6d2511dc198d',
-			'org.ow2.asm:asm:5.0.4:asm-5.0.4.jar:896618ed8ae62702521a78bc7be42b7c491a08e6920a15f89a3ecdec31e9a220',
-	]
-}
-
 // needed to make test output available to bramble-core and briar-core
 configurations {
 	testOutput.extendsFrom(testCompile)
@@ -0,0 +1,10 @@
+package org.briarproject.bramble.api;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface Nameable {
+
+	String getName();
+
+}
@@ -0,0 +1,26 @@
+package org.briarproject.bramble.api;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+public class Pair<A, B> {
+
+	private final A first;
+	private final B second;
+
+	public Pair(A first, B second) {
+		this.first = first;
+		this.second = second;
+	}
+
+	public A getFirst() {
+		return first;
+	}
+
+	public B getSecond() {
+		return second;
+	}
+}
@@ -38,4 +38,18 @@ public abstract class StringMap extends Hashtable<String, String> {
 	public void putInt(String key, int value) {
 		put(key, String.valueOf(value));
 	}
+
+	public long getLong(String key, long defaultValue) {
+		String s = get(key);
+		if (s == null) return defaultValue;
+		try {
+			return Long.valueOf(s);
+		} catch (NumberFormatException e) {
+			return defaultValue;
+		}
+	}
+
+	public void putLong(String key, long value) {
+		put(key, String.valueOf(value));
+	}
 }
@@ -1,9 +0,0 @@
-package org.briarproject.bramble.api;
-
-import java.io.IOException;
-
-/**
- * An exception that indicates an unrecoverable version mismatch.
- */
-public class UnsupportedVersionException extends IOException {
-}
@@ -0,0 +1,6 @@
+package org.briarproject.bramble.api.battery;
+
+public interface BatteryManager {
+
+	boolean isCharging();
+}
@@ -0,0 +1,19 @@
+package org.briarproject.bramble.api.battery.event;
+
+import org.briarproject.bramble.api.event.Event;
+
+/**
+ * An event that is broadcast when the device starts or stops charging.
+ */
+public class BatteryEvent extends Event {
+
+	private final boolean charging;
+
+	public BatteryEvent(boolean charging) {
+		this.charging = charging;
+	}
+
+	public boolean isCharging() {
+		return charging;
+	}
+}
@@ -1,7 +1,6 @@
-package org.briarproject.briar.client;
+package org.briarproject.bramble.api.client;

 import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.client.ClientHelper;
 import org.briarproject.bramble.api.data.BdfDictionary;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.data.MetadataParser;
@@ -12,7 +11,7 @@ import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.InvalidMessageException;
 import org.briarproject.bramble.api.sync.Message;
-import org.briarproject.bramble.api.sync.ValidationManager.IncomingMessageHook;
+import org.briarproject.bramble.api.sync.validation.IncomingMessageHook;

 import javax.annotation.concurrent.Immutable;

@@ -62,5 +61,4 @@ public abstract class BdfIncomingMessageHook implements IncomingMessageHook {
 			throw new InvalidMessageException(e);
 		}
 	}
-
 }
@@ -9,14 +9,13 @@ import org.briarproject.bramble.api.sync.Group;
 import org.briarproject.bramble.api.sync.InvalidMessageException;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageContext;
-import org.briarproject.bramble.api.sync.ValidationManager.MessageValidator;
+import org.briarproject.bramble.api.sync.validation.MessageValidator;
 import org.briarproject.bramble.api.system.Clock;

 import java.util.logging.Logger;

 import javax.annotation.concurrent.Immutable;

-import static org.briarproject.bramble.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
 import static org.briarproject.bramble.api.transport.TransportConstants.MAX_CLOCK_DIFFERENCE;

@Immutable
@@ -49,14 +48,9 @@ public abstract class BdfMessageValidator implements MessageValidator {
 			throw new InvalidMessageException(
 					"Timestamp is too far in the future");
 		}
-		byte[] raw = m.getRaw();
-		if (raw.length <= MESSAGE_HEADER_LENGTH) {
-			throw new InvalidMessageException("Message is too short");
-		}
 		try {
-			BdfList body = clientHelper.toList(raw, MESSAGE_HEADER_LENGTH,
-					raw.length - MESSAGE_HEADER_LENGTH);
-			BdfMessageContext result = validateMessage(m, g, body);
+			BdfList bodyList = clientHelper.toList(m.getBody());
+			BdfMessageContext result = validateMessage(m, g, bodyList);
 			Metadata meta = metadataEncoder.encode(result.getDictionary());
 			return new MessageContext(meta, result.getDependencies());
 		} catch (FormatException e) {
@@ -16,8 +16,6 @@ import org.briarproject.bramble.api.sync.MessageId;
 import java.security.GeneralSecurityException;
 import java.util.Map;

-import javax.annotation.Nullable;
-
@NotNullByDefault
 public interface ClientHelper {

@@ -32,16 +30,12 @@ public interface ClientHelper {

 	Message createMessageForStoringMetadata(GroupId g);

-	@Nullable
 	Message getMessage(MessageId m) throws DbException;

-	@Nullable
 	Message getMessage(Transaction txn, MessageId m) throws DbException;

-	@Nullable
 	BdfList getMessageAsList(MessageId m) throws DbException, FormatException;

-	@Nullable
 	BdfList getMessageAsList(Transaction txn, MessageId m) throws DbException,
 			FormatException;

@@ -4,8 +4,12 @@ import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;

+import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;

+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
+import static org.briarproject.bramble.util.StringUtils.toUtf8;
+
@Immutable
@NotNullByDefault
 public class Contact {
@@ -13,13 +17,21 @@ public class Contact {
 	private final ContactId id;
 	private final Author author;
 	private final AuthorId localAuthorId;
+	@Nullable
+	private final String alias;
 	private final boolean verified, active;

 	public Contact(ContactId id, Author author, AuthorId localAuthorId,
-			boolean verified, boolean active) {
+			@Nullable String alias, boolean verified, boolean active) {
+		if (alias != null) {
+			int aliasLength = toUtf8(alias).length;
+			if (aliasLength == 0 || aliasLength > MAX_AUTHOR_NAME_LENGTH)
+				throw new IllegalArgumentException();
+		}
 		this.id = id;
 		this.author = author;
 		this.localAuthorId = localAuthorId;
+		this.alias = alias;
 		this.verified = verified;
 		this.active = active;
 	}
@@ -36,6 +48,11 @@ public class Contact {
 		return localAuthorId;
 	}

+	@Nullable
+	public String getAlias() {
+		return alias;
+	}
+
 	public boolean isVerified() {
 		return verified;
 	}
@@ -5,11 +5,14 @@ import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.identity.AuthorInfo;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;

 import java.util.Collection;

+import javax.annotation.Nullable;
+
@NotNullByDefault
 public interface ContactManager {

@@ -93,6 +96,18 @@ public interface ContactManager {
 	void setContactActive(Transaction txn, ContactId c, boolean active)
 			throws DbException;

+	/**
+	 * Sets an alias name for the contact or unsets it if alias is null.
+	 */
+	void setContactAlias(Transaction txn, ContactId c, @Nullable String alias)
+			throws DbException;
+
+	/**
+	 * Sets an alias name for the contact or unsets it if alias is null.
+	 */
+	void setContactAlias(ContactId c, @Nullable String alias)
+			throws DbException;
+
 	/**
 	 * Return true if a contact with this name and public key already exists
 	 */
@@ -105,6 +120,16 @@ public interface ContactManager {
 	boolean contactExists(AuthorId remoteAuthorId, AuthorId localAuthorId)
 			throws DbException;

+	/**
+	 * Returns the {@link AuthorInfo} for the given author.
+	 */
+	AuthorInfo getAuthorInfo(AuthorId a) throws DbException;
+
+	/**
+	 * Returns the {@link AuthorInfo} for the given author.
+	 */
+	AuthorInfo getAuthorInfo(Transaction txn, AuthorId a) throws DbException;
+
 	interface ContactHook {

 		void addingContact(Transaction txn, Contact c) throws DbException;
@@ -0,0 +1,71 @@
+package org.briarproject.bramble.api.data;
+
+import org.briarproject.bramble.api.Bytes;
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import javax.annotation.Nullable;
+
+import static org.briarproject.bramble.api.data.BdfDictionary.NULL_VALUE;
+import static org.briarproject.bramble.util.StringUtils.toHexString;
+
+@NotNullByDefault
+public class BdfStringUtils {
+
+	public static String toString(@Nullable Object o) throws FormatException {
+		return toString(o, 0);
+	}
+
+	private static String toString(@Nullable Object o, int indent)
+			throws FormatException {
+		if (o == null || o == NULL_VALUE) return "null";
+		if (o instanceof Boolean) return o.toString();
+		if (o instanceof Number) return o.toString();
+		if (o instanceof String) return "\"" + o + "\"";
+		if (o instanceof Bytes)
+			return "x" + toHexString(((Bytes) o).getBytes());
+		if (o instanceof byte[])
+			return "x" + toHexString((byte[]) o);
+		if (o instanceof List) {
+			List<?> list = (List) o;
+			StringBuilder sb = new StringBuilder();
+			sb.append("[\n");
+			int i = 0, size = list.size();
+			for (Object e : list) {
+				indent(sb, indent + 1);
+				sb.append(toString(e, indent + 1));
+				if (i++ < size - 1) sb.append(',');
+				sb.append('\n');
+			}
+			indent(sb, indent);
+			sb.append(']');
+			return sb.toString();
+		}
+		if (o instanceof Map) {
+			Map<?, ?> map = (Map) o;
+			StringBuilder sb = new StringBuilder();
+			sb.append("{\n");
+			int i = 0, size = map.size();
+			for (Entry e : map.entrySet()) {
+				indent(sb, indent + 1);
+				sb.append(toString(e.getKey(), indent + 1));
+				sb.append(": ");
+				sb.append(toString(e.getValue(), indent + 1));
+				if (i++ < size - 1) sb.append(',');
+				sb.append('\n');
+			}
+			indent(sb, indent);
+			sb.append('}');
+			return sb.toString();
+		}
+		throw new FormatException();
+	}
+
+	private static void indent(StringBuilder sb, int indent) {
+		for (int i = 0; i < indent; i++) sb.append('\t');
+	}
+}
@@ -19,6 +19,7 @@ import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.MessageStatus;
 import org.briarproject.bramble.api.sync.Offer;
 import org.briarproject.bramble.api.sync.Request;
+import org.briarproject.bramble.api.sync.validation.MessageState;
 import org.briarproject.bramble.api.transport.KeySet;
 import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
@@ -28,8 +29,6 @@ import java.util.Map;

 import javax.annotation.Nullable;

-import static org.briarproject.bramble.api.sync.ValidationManager.State;
-
 /**
 * Encapsulates the database implementation and exposes high-level operations
 * to other components.
@@ -76,6 +75,27 @@ public interface DatabaseComponent {
 	 */
 	void endTransaction(Transaction txn);

+	/**
+	 * Runs the given task within a transaction.
+	 */
+	<E extends Exception> void transaction(boolean readOnly,
+			DbRunnable<E> task) throws DbException, E;
+
+	/**
+	 * Runs the given task within a transaction and returns the result of the
+	 * task.
+	 */
+	<R, E extends Exception> R transactionWithResult(boolean readOnly,
+			DbCallable<R, E> task) throws DbException, E;
+
+	/**
+	 * Runs the given task within a transaction and returns the result of the
+	 * task, which may be null.
+	 */
+	@Nullable
+	<R, E extends Exception> R transactionWithNullableResult(boolean readOnly,
+			NullableDbCallable<R, E> task) throws DbException, E;
+
 	/**
 	 * Stores a contact associated with the given local and remote pseudonyms,
 	 * and returns an ID for the contact.
@@ -151,13 +171,13 @@ public interface DatabaseComponent {
 			throws DbException;

 	/**
-	 * Returns a batch of raw messages for the given contact, with a total
-	 * length less than or equal to the given length, for transmission over a
+	 * Returns a batch of messages for the given contact, with a total length
+	 * less than or equal to the given length, for transmission over a
 	 * transport with the given maximum latency. Returns null if there are no
 	 * sendable messages that fit in the given length.
 	 */
 	@Nullable
-	Collection<byte[]> generateBatch(Transaction txn, ContactId c,
+	Collection<Message> generateBatch(Transaction txn, ContactId c,
 			int maxLength, int maxLatency) throws DbException;

 	/**
@@ -178,14 +198,14 @@ public interface DatabaseComponent {
 			throws DbException;

 	/**
-	 * Returns a batch of raw messages for the given contact, with a total
-	 * length less than or equal to the given length, for transmission over a
+	 * Returns a batch of messages for the given contact, with a total length
+	 * less than or equal to the given length, for transmission over a
 	 * transport with the given maximum latency. Only messages that have been
 	 * requested by the contact are returned. Returns null if there are no
 	 * sendable messages that fit in the given length.
 	 */
 	@Nullable
-	Collection<byte[]> generateRequestedBatch(Transaction txn, ContactId c,
+	Collection<Message> generateRequestedBatch(Transaction txn, ContactId c,
 			int maxLength, int maxLatency) throws DbException;

 	/**
@@ -263,6 +283,15 @@ public interface DatabaseComponent {
 	 */
 	Collection<LocalAuthor> getLocalAuthors(Transaction txn) throws DbException;

+	/**
+	 * Returns the message with the given ID.
+	 * <p/>
+	 * Read-only.
+	 *
+	 * @throws MessageDeletedException if the message has been deleted
+	 */
+	Message getMessage(Transaction txn, MessageId m) throws DbException;
+
 	/**
 	 * Returns the IDs of all delivered messages in the given group.
 	 * <p/>
@@ -297,15 +326,6 @@ public interface DatabaseComponent {
 	Collection<MessageId> getMessagesToShare(Transaction txn)
 			throws DbException;

-	/**
-	 * Returns the message with the given ID, in serialised form, or null if
-	 * the message has been deleted.
-	 * <p/>
-	 * Read-only.
-	 */
-	@Nullable
-	byte[] getRawMessage(Transaction txn, MessageId m) throws DbException;
-
 	/**
 	 * Returns the metadata for all delivered messages in the given group.
 	 * <p/>
@@ -353,12 +373,12 @@ public interface DatabaseComponent {
 	/**
 	 * Returns the IDs and states of all dependencies of the given message.
 	 * For missing dependencies and dependencies in other groups, the state
-	 * {@link State UNKNOWN} is returned.
+	 * {@link MessageState UNKNOWN} is returned.
 	 * <p/>
 	 * Read-only.
 	 */
-	Map<MessageId, State> getMessageDependencies(Transaction txn, MessageId m)
-			throws DbException;
+	Map<MessageId, MessageState> getMessageDependencies(Transaction txn,
+			MessageId m) throws DbException;

 	/**
 	 * Returns the IDs and states of all dependents of the given message.
@@ -367,15 +387,16 @@ public interface DatabaseComponent {
 	 * <p/>
 	 * Read-only.
 	 */
-	Map<MessageId, State> getMessageDependents(Transaction txn, MessageId m)
-			throws DbException;
+	Map<MessageId, MessageState> getMessageDependents(Transaction txn,
+			MessageId m) throws DbException;

 	/**
 	 * Gets the validation and delivery state of the given message.
 	 * <p/>
 	 * Read-only.
 	 */
-	State getMessageState(Transaction txn, MessageId m) throws DbException;
+	MessageState getMessageState(Transaction txn, MessageId m)
+			throws DbException;

 	/**
 	 * Returns the status of the given delivered message with respect to the
@@ -502,6 +523,12 @@ public interface DatabaseComponent {
 	void setContactActive(Transaction txn, ContactId c, boolean active)
 			throws DbException;

+	/**
+	 * Sets an alias name for the contact or unsets it if alias is null.
+	 */
+	void setContactAlias(Transaction txn, ContactId c, @Nullable String alias)
+			throws DbException;
+
 	/**
 	 * Sets the given group's visibility to the given contact.
 	 */
@@ -516,7 +543,7 @@ public interface DatabaseComponent {
 	/**
 	 * Sets the validation and delivery state of the given message.
 	 */
-	void setMessageState(Transaction txn, MessageId m, State state)
+	void setMessageState(Transaction txn, MessageId m, MessageState state)
 			throws DbException;

 	/**
@@ -0,0 +1,9 @@
+package org.briarproject.bramble.api.db;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface DbCallable<R, E extends Exception> {
+
+	R call(Transaction txn) throws DbException, E;
+}
@@ -0,0 +1,9 @@
+package org.briarproject.bramble.api.db;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface DbRunnable<E extends Exception> {
+
+	void run(Transaction txn) throws DbException, E;
+}
@@ -0,0 +1,9 @@
+package org.briarproject.bramble.api.db;
+
+/**
+ * Thrown when a message that has been deleted is requested from the database.
+ * This exception may occur due to concurrent updates and does not indicate a
+ * database error.
+ */
+public class MessageDeletedException extends DbException {
+}
@@ -6,6 +6,10 @@ public interface MigrationListener {
 	 * This is called when a migration is started while opening the database.
 	 * It will be called once for each migration being applied.
 	 */
-	void onMigrationRun();
+	void onDatabaseMigration();

+	/**
+	 * This is called when compaction is started while opening the database.
+	 */
+	void onDatabaseCompaction();
 }
@@ -0,0 +1,12 @@
+package org.briarproject.bramble.api.db;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.Nullable;
+
+@NotNullByDefault
+public interface NullableDbCallable<R, E extends Exception> {
+
+	@Nullable
+	R call(Transaction txn) throws DbException, E;
+}
@@ -1,5 +1,6 @@
 package org.briarproject.bramble.api.identity;

+import org.briarproject.bramble.api.Nameable;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.util.StringUtils;

@@ -13,11 +14,7 @@ import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_K
 */
@Immutable
@NotNullByDefault
-public class Author {
-
-	public enum Status {
-		NONE, ANONYMOUS, UNKNOWN, UNVERIFIED, VERIFIED, OURSELVES
-	}
+public class Author implements Nameable {

 	/**
 	 * The current version of the author structure.
@@ -0,0 +1,56 @@
+package org.briarproject.bramble.api.identity;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+public class AuthorInfo {
+
+	public enum Status {
+		NONE, ANONYMOUS, UNKNOWN, UNVERIFIED, VERIFIED, OURSELVES;
+
+		public boolean isContact() {
+			return this == UNVERIFIED || this == VERIFIED;
+		}
+	}
+
+	private final Status status;
+	@Nullable
+	private final String alias;
+
+	public AuthorInfo(Status status, @Nullable String alias) {
+		this.status = status;
+		this.alias = alias;
+	}
+
+	public AuthorInfo(Status status) {
+		this(status, null);
+	}
+
+	public Status getStatus() {
+		return status;
+	}
+
+	@Nullable
+	public String getAlias() {
+		return alias;
+	}
+
+	@Override
+	public int hashCode() {
+		int hashCode = status.ordinal();
+		if (alias != null) hashCode += alias.hashCode();
+		return hashCode;
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if (!(o instanceof AuthorInfo)) return false;
+		AuthorInfo info = (AuthorInfo) o;
+		return status == info.status &&
+				(alias == null ? info.alias == null : alias.equals(info.alias));
+	}
+}
@@ -3,7 +3,6 @@ package org.briarproject.bramble.api.identity;
 import org.briarproject.bramble.api.crypto.CryptoExecutor;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
-import org.briarproject.bramble.api.identity.Author.Status;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;

@NotNullByDefault
@@ -37,14 +36,4 @@ public interface IdentityManager {
 	 */
 	LocalAuthor getLocalAuthor(Transaction txn) throws DbException;

-	/**
-	 * Returns the {@link Status} of the given author.
-	 */
-	Status getAuthorStatus(AuthorId a) throws DbException;
-
-	/**
-	 * Returns the {@link Status} of the given author.
-	 */
-	Status getAuthorStatus(Transaction txn, AuthorId a) throws DbException;
-
 }
@@ -3,20 +3,16 @@ package org.briarproject.bramble.api.keyagreement;
 public interface KeyAgreementConstants {

 	/**
-	 * The current version of the BQP protocol. Version number 89 is reserved.
+	 * The version of the BQP protocol used in beta releases. This version
+	 * number is reserved.
+	 */
+	byte BETA_PROTOCOL_VERSION = 89;
+
+	/**
+	 * The current version of the BQP protocol.
 	 */
 	byte PROTOCOL_VERSION = 4;

-	/**
-	 * The length of the record header in bytes.
-	 */
-	int RECORD_HEADER_LENGTH = 4;
-
-	/**
-	 * The offset of the payload length in the record header, in bytes.
-	 */
-	int RECORD_HEADER_PAYLOAD_LENGTH_OFFSET = 2;
-
 	/**
 	 * The length of the BQP key commitment in bytes.
 	 */
@@ -25,7 +21,7 @@ public interface KeyAgreementConstants {
 	/**
 	 * The connection timeout in milliseconds.
 	 */
-	long CONNECTION_TIMEOUT = 20 * 1000;
+	long CONNECTION_TIMEOUT = 60_000;

 	/**
 	 * The transport identifier for Bluetooth.
@@ -0,0 +1,20 @@
+package org.briarproject.bramble.api.keyagreement;
+
+import java.io.IOException;
+
+/**
+ * Thrown when a QR code that has been scanned uses a protocol version that is
+ * not supported.
+ */
+public class UnsupportedVersionException extends IOException {
+
+	private final boolean tooOld;
+
+	public UnsupportedVersionException(boolean tooOld) {
+		this.tooOld = tooOld;
+	}
+
+	public boolean isTooOld() {
+		return tooOld;
+	}
+}
@@ -34,7 +34,8 @@ public interface LifecycleManager {
 	 */
 	enum LifecycleState {

-		STARTING, MIGRATING_DATABASE, STARTING_SERVICES, RUNNING, STOPPING;
+		STARTING, MIGRATING_DATABASE, COMPACTING_DATABASE, STARTING_SERVICES,
+		RUNNING, STOPPING;

 		public boolean isAfter(LifecycleState state) {
 			return ordinal() > state.ordinal();
@@ -0,0 +1,15 @@
+package org.briarproject.bramble.api.nullsafety;
+
+import javax.annotation.Nullable;
+
+@NotNullByDefault
+public class NullSafety {
+
+	/**
+	 * Stand-in for `Objects.requireNonNull()`.
+	 */
+	public static <T> T requireNonNull(@Nullable T t) {
+		if (t == null) throw new NullPointerException();
+		return t;
+	}
+}
@@ -4,7 +4,8 @@ public interface TorConstants {

 	TransportId ID = new TransportId("org.briarproject.bramble.tor");

-	String PROP_ONION = "onion";
+	String PROP_ONION_V2 = "onion";
+	String PROP_ONION_V3 = "onion3";

 	int SOCKS_PORT = 59050;
 	int CONTROL_PORT = 59051;
@@ -12,12 +13,13 @@ public interface TorConstants {
 	int CONNECT_TO_PROXY_TIMEOUT = 5000; // Milliseconds
 	int EXTRA_SOCKET_TIMEOUT = 30000; // Milliseconds

-	String PREF_TOR_NETWORK = "network";
+	String PREF_TOR_NETWORK = "network2";
 	String PREF_TOR_PORT = "port";
-	String PREF_TOR_DISABLE_BLOCKED = "disableWhenBlocked";
+	String PREF_TOR_MOBILE = "useMobileData";

-	int PREF_TOR_NETWORK_NEVER = 0;
-	int PREF_TOR_NETWORK_WIFI = 1;
-	int PREF_TOR_NETWORK_ALWAYS = 2;
+	int PREF_TOR_NETWORK_AUTOMATIC = 0;
+	int PREF_TOR_NETWORK_WITHOUT_BRIDGES = 1;
+	int PREF_TOR_NETWORK_WITH_BRIDGES = 2;
+	int PREF_TOR_NETWORK_NEVER = 3;

 }
@@ -1,6 +1,7 @@
 package org.briarproject.bramble.api.settings;

 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;

@NotNullByDefault
@@ -11,6 +12,11 @@ public interface SettingsManager {
 	 */
 	Settings getSettings(String namespace) throws DbException;

+	/**
+	 * Returns all settings in the given namespace.
+	 */
+	Settings getSettings(Transaction txn, String namespace) throws DbException;
+
 	/**
 	 * Merges the given settings with any existing settings in the given
 	 * namespace.
@@ -2,6 +2,7 @@ package org.briarproject.bramble.api.settings.event;

 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.settings.Settings;

 import javax.annotation.concurrent.Immutable;

@@ -13,12 +14,18 @@ import javax.annotation.concurrent.Immutable;
 public class SettingsUpdatedEvent extends Event {

 	private final String namespace;
+	private final Settings settings;

-	public SettingsUpdatedEvent(String namespace) {
+	public SettingsUpdatedEvent(String namespace, Settings settings) {
 		this.namespace = namespace;
+		this.settings = settings;
 	}

 	public String getNamespace() {
 		return namespace;
 	}
+
+	public Settings getSettings() {
+		return settings;
+	}
 }
@@ -1,6 +1,6 @@
 package org.briarproject.bramble.api.sync;

-import static org.briarproject.bramble.api.sync.SyncConstants.MAX_MESSAGE_LENGTH;
+import static org.briarproject.bramble.api.sync.SyncConstants.MAX_MESSAGE_BODY_LENGTH;
 import static org.briarproject.bramble.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;

 public class Message {
@@ -13,17 +13,16 @@ public class Message {
 	private final MessageId id;
 	private final GroupId groupId;
 	private final long timestamp;
-	private final byte[] raw;
+	private final byte[] body;

-	public Message(MessageId id, GroupId groupId, long timestamp, byte[] raw) {
-		if (raw.length <= MESSAGE_HEADER_LENGTH)
-			throw new IllegalArgumentException();
-		if (raw.length > MAX_MESSAGE_LENGTH)
+	public Message(MessageId id, GroupId groupId, long timestamp, byte[] body) {
+		if (body.length == 0) throw new IllegalArgumentException();
+		if (body.length > MAX_MESSAGE_BODY_LENGTH)
 			throw new IllegalArgumentException();
 		this.id = id;
 		this.groupId = groupId;
 		this.timestamp = timestamp;
-		this.raw = raw;
+		this.body = body;
 	}

 	/**
@@ -50,15 +49,15 @@ public class Message {
 	/**
 	 * Returns the length of the raw message in bytes.
 	 */
-	public int getLength() {
-		return raw.length;
+	public int getRawLength() {
+		return MESSAGE_HEADER_LENGTH + body.length;
 	}

 	/**
-	 * Returns the raw message.
+	 * Returns the message body.
 	 */
-	public byte[] getRaw() {
-		return raw;
+	public byte[] getBody() {
+		return body;
 	}

 	@Override
@@ -9,5 +9,5 @@ public interface MessageFactory {

 	Message createMessage(byte[] raw);

-	Message createMessage(MessageId m, byte[] raw);
+	byte[] getRawMessage(Message m);
 }
@@ -9,7 +9,7 @@ public interface SyncRecordWriter {

 	void writeAck(Ack a) throws IOException;

-	void writeMessage(byte[] raw) throws IOException;
+	void writeMessage(Message m) throws IOException;

 	void writeOffer(Offer o) throws IOException;

@@ -1,87 +0,0 @@
-package org.briarproject.bramble.api.sync;
-
-import org.briarproject.bramble.api.crypto.SecretKey;
-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;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-/**
- * Responsible for managing message validators and passing them messages to
- * validate.
- */
-@NotNullByDefault
-public interface ValidationManager {
-
-	enum State {
-
-		UNKNOWN(0), INVALID(1), PENDING(2), DELIVERED(3);
-
-		private final int value;
-
-		State(int value) {
-			this.value = value;
-		}
-
-		public int getValue() {
-			return value;
-		}
-
-		public static State fromValue(int value) {
-			for (State s : values()) if (s.value == value) return s;
-			throw new IllegalArgumentException();
-		}
-	}
-
-	/**
-	 * Registers the message validator for the given client. This method
-	 * should be called before
-	 * {@link LifecycleManager#startServices(SecretKey)}.
-	 */
-	void registerMessageValidator(ClientId c, int majorVersion,
-			MessageValidator v);
-
-	/**
-	 * Registers the incoming message hook for the given client. The hook will
-	 * be called once for each incoming message that passes validation. This
-	 * method should be called before
-	 * {@link LifecycleManager#startServices(SecretKey)}.
-	 */
-	void registerIncomingMessageHook(ClientId c, int majorVersion,
-			IncomingMessageHook hook);
-
-	interface MessageValidator {
-
-		/**
-		 * Validates the given message and returns its metadata and
-		 * dependencies.
-		 */
-		MessageContext validateMessage(Message m, Group g)
-				throws InvalidMessageException;
-	}
-
-	interface IncomingMessageHook {
-
-		/**
-		 * Called once for each incoming message that passes validation.
-		 *
-		 * @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,
-		 * the message will be permanently invalidated.
-		 * @throws InvalidMessageException for any non-database error
-		 * that occurs while handling remotely created data.
-		 * This includes errors that occur while handling locally created data
-		 * in a context controlled by remotely created data
-		 * (for example, parsing the metadata of a dependency
-		 * of an incoming message).
-		 * Throwing this will delete the incoming message and its metadata
-		 * marking it as invalid in the database.
-		 * Never rethrow DbException as InvalidMessageException!
-		 */
-		boolean incomingMessage(Transaction txn, Message m, Metadata meta)
-				throws DbException, InvalidMessageException;
-	}
-}
@@ -3,11 +3,10 @@ package org.briarproject.bramble.api.sync.event;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.bramble.api.sync.validation.MessageState;

 import javax.annotation.concurrent.Immutable;

-import static org.briarproject.bramble.api.sync.ValidationManager.State;
-
 /**
 * An event that is broadcast when a message state changed.
 */
@@ -17,10 +16,10 @@ public class MessageStateChangedEvent extends Event {

 	private final MessageId messageId;
 	private final boolean local;
-	private final State state;
+	private final MessageState state;

 	public MessageStateChangedEvent(MessageId messageId, boolean local,
-			State state) {
+			MessageState state) {
 		this.messageId = messageId;
 		this.local = local;
 		this.state = state;
@@ -34,7 +33,7 @@ public class MessageStateChangedEvent extends Event {
 		return local;
 	}

-	public State getState() {
+	public MessageState getState() {
 		return state;
 	}

@@ -0,0 +1,31 @@
+package org.briarproject.bramble.api.sync.validation;
+
+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.sync.InvalidMessageException;
+import org.briarproject.bramble.api.sync.Message;
+
+public interface IncomingMessageHook {
+
+	/**
+	 * Called once for each incoming message that passes validation.
+	 *
+	 * @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,
+	 * the message will be permanently invalidated.
+	 * @throws InvalidMessageException for any non-database error
+	 * that occurs while handling remotely created data.
+	 * This includes errors that occur while handling locally created data
+	 * in a context controlled by remotely created data
+	 * (for example, parsing the metadata of a dependency
+	 * of an incoming message).
+	 * Throwing this will delete the incoming message and its metadata
+	 * marking it as invalid in the database.
+	 * Never rethrow DbException as InvalidMessageException!
+	 */
+	boolean incomingMessage(Transaction txn, Message m, Metadata meta)
+			throws DbException, InvalidMessageException;
+}
@@ -0,0 +1,21 @@
+package org.briarproject.bramble.api.sync.validation;
+
+public enum MessageState {
+
+	UNKNOWN(0), INVALID(1), PENDING(2), DELIVERED(3);
+
+	private final int value;
+
+	MessageState(int value) {
+		this.value = value;
+	}
+
+	public int getValue() {
+		return value;
+	}
+
+	public static MessageState fromValue(int value) {
+		for (MessageState s : values()) if (s.value == value) return s;
+		throw new IllegalArgumentException();
+	}
+}
@@ -0,0 +1,16 @@
+package org.briarproject.bramble.api.sync.validation;
+
+import org.briarproject.bramble.api.sync.Group;
+import org.briarproject.bramble.api.sync.InvalidMessageException;
+import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.sync.MessageContext;
+
+public interface MessageValidator {
+
+	/**
+	 * Validates the given message and returns its metadata and
+	 * dependencies.
+	 */
+	MessageContext validateMessage(Message m, Group g)
+			throws InvalidMessageException;
+}
@@ -0,0 +1,31 @@
+package org.briarproject.bramble.api.sync.validation;
+
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.ClientId;
+
+/**
+ * Responsible for managing message validators and passing them messages to
+ * validate.
+ */
+@NotNullByDefault
+public interface ValidationManager {
+
+	/**
+	 * Registers the {@link MessageValidator} for the given client. This method
+	 * should be called before
+	 * {@link LifecycleManager#startServices(SecretKey)}.
+	 */
+	void registerMessageValidator(ClientId c, int majorVersion,
+			MessageValidator v);
+
+	/**
+	 * Registers the {@link IncomingMessageHook} for the given client. The hook
+	 * will be called once for each incoming message that passes validation.
+	 * This method should be called before
+	 * {@link LifecycleManager#startServices(SecretKey)}.
+	 */
+	void registerIncomingMessageHook(ClientId c, int majorVersion,
+			IncomingMessageHook hook);
+}
@@ -0,0 +1,11 @@
+package org.briarproject.bramble.api.system;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.io.InputStream;
+
+@NotNullByDefault
+public interface ResourceProvider {
+
+	InputStream getResourceInputStream(String name, String extension);
+}
@@ -47,7 +47,7 @@ public class StringUtils {
 		try {
 			return s.getBytes("UTF-8");
 		} catch (UnsupportedEncodingException e) {
-			throw new RuntimeException(e);
+			throw new AssertionError(e);
 		}
 	}

@@ -63,7 +63,7 @@ public class StringUtils {
 		try {
 			return decoder.decode(buffer).toString();
 		} catch (CharacterCodingException e) {
-			throw new RuntimeException(e);
+			throw new AssertionError(e);
 		}
 	}

@@ -0,0 +1,42 @@
+package org.briarproject.bramble.api.identity;
+
+import org.briarproject.bramble.test.BrambleTestCase;
+import org.junit.Test;
+
+import static org.briarproject.bramble.api.identity.AuthorInfo.Status.NONE;
+import static org.briarproject.bramble.api.identity.AuthorInfo.Status.VERIFIED;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+
+public class AuthorInfoTest extends BrambleTestCase {
+
+	@Test
+	public void testEquals() {
+		assertEquals(
+				new AuthorInfo(NONE),
+				new AuthorInfo(NONE, null)
+		);
+		assertEquals(
+				new AuthorInfo(NONE, "test"),
+				new AuthorInfo(NONE, "test")
+		);
+
+		assertNotEquals(
+				new AuthorInfo(NONE),
+				new AuthorInfo(VERIFIED)
+		);
+		assertNotEquals(
+				new AuthorInfo(NONE, "test"),
+				new AuthorInfo(NONE)
+		);
+		assertNotEquals(
+				new AuthorInfo(NONE),
+				new AuthorInfo(NONE, "test")
+		);
+		assertNotEquals(
+				new AuthorInfo(NONE, "a"),
+				new AuthorInfo(NONE, "b")
+		);
+	}
+
+}
@@ -0,0 +1,23 @@
+package org.briarproject.bramble.test;
+
+import org.briarproject.bramble.api.system.Clock;
+
+public class ArrayClock implements Clock {
+
+	private final long[] times;
+	private int index = 0;
+
+	public ArrayClock(long... times) {
+		this.times = times;
+	}
+
+	@Override
+	public long currentTimeMillis() {
+		return times[index++];
+	}
+
+	@Override
+	public void sleep(long milliseconds) throws InterruptedException {
+		Thread.sleep(milliseconds);
+	}
+}
@@ -0,0 +1,24 @@
+package org.briarproject.bramble.test;
+
+import org.briarproject.bramble.api.system.Clock;
+
+import java.util.concurrent.atomic.AtomicLong;
+
+public class SettableClock implements Clock {
+
+	private final AtomicLong time;
+
+	public SettableClock(AtomicLong time) {
+		this.time = time;
+	}
+
+	@Override
+	public long currentTimeMillis() {
+		return time.get();
+	}
+
+	@Override
+	public void sleep(long milliseconds) throws InterruptedException {
+		Thread.sleep(milliseconds);
+	}
+}
@@ -24,6 +24,7 @@ import java.util.Map;
 import java.util.Random;
 import java.util.concurrent.atomic.AtomicInteger;

+import static java.util.Arrays.asList;
 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;
@@ -32,7 +33,6 @@ import static org.briarproject.bramble.api.properties.TransportPropertyConstants
 import static org.briarproject.bramble.api.sync.ClientId.MAX_CLIENT_ID_LENGTH;
 import static org.briarproject.bramble.api.sync.SyncConstants.MAX_GROUP_DESCRIPTOR_LENGTH;
 import static org.briarproject.bramble.api.sync.SyncConstants.MAX_MESSAGE_BODY_LENGTH;
-import static org.briarproject.bramble.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
 import static org.briarproject.bramble.util.StringUtils.getRandomString;

 public class TestUtils {
@@ -40,6 +40,7 @@ public class TestUtils {
 	private static final AtomicInteger nextTestDir =
 			new AtomicInteger((int) (Math.random() * 1000 * 1000));
 	private static final Random random = new Random();
+	private static final long timestamp = System.currentTimeMillis();

 	public static File getTestDirectory() {
 		int name = nextTestDir.getAndIncrement();
@@ -101,9 +102,8 @@ public class TestUtils {
 		String name = getRandomString(nameLength);
 		byte[] publicKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
 		byte[] privateKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
-		long created = System.currentTimeMillis();
 		return new LocalAuthor(id, FORMAT_VERSION, name, publicKey, privateKey,
-				created);
+				timestamp);
 	}

 	public static Author getAuthor() {
@@ -131,14 +131,13 @@ public class TestUtils {

 	public static Message getMessage(GroupId groupId) {
 		int bodyLength = 1 + random.nextInt(MAX_MESSAGE_BODY_LENGTH);
-		return getMessage(groupId, MESSAGE_HEADER_LENGTH + bodyLength);
+		return getMessage(groupId, bodyLength);
 	}

-	public static Message getMessage(GroupId groupId, int rawLength) {
+	public static Message getMessage(GroupId groupId, int bodyLength) {
 		MessageId id = new MessageId(getRandomId());
-		byte[] raw = getRandomBytes(rawLength);
-		long timestamp = System.currentTimeMillis();
-		return new Message(id, groupId, timestamp, raw);
+		byte[] body = getRandomBytes(bodyLength);
+		return new Message(id, groupId, timestamp, body);
 	}

 	public static double getMedian(Collection<? extends Number> samples) {
@@ -174,4 +173,10 @@ public class TestUtils {
 			Collection<? extends Number> samples) {
 		return Math.sqrt(getVariance(samples));
 	}
+
+	public static boolean isOptionalTestEnabled(Class testClass) {
+		String optionalTests = System.getenv("OPTIONAL_TESTS");
+		return optionalTests != null &&
+				asList(optionalTests.split(",")).contains(testClass.getName());
+	}
 }
@@ -0,0 +1,24 @@
+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',
+        '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',
+        'org.apache.ant:ant:1.9.4:ant-1.9.4.jar:649ae0730251de07b8913f49286d46bba7b92d47c5f332610aa426c4f02161d8',
+        'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
+        'org.codehaus.mojo.signature:java16:1.1:java16-1.1.signature:53799223a2c98dba2d0add810bed76315460df285c69e4f397ae6098f87dd619',
+        'org.codehaus.mojo:animal-sniffer-ant-tasks:1.16:animal-sniffer-ant-tasks-1.16.jar:890040976fbe2d584619a6a61b1fd2e925b3b5eb342a85eb2762c467c0d64e90',
+        'org.codehaus.mojo:animal-sniffer:1.16:animal-sniffer-1.16.jar:72be8bcc226ba43b937c722a08a07852bfa1b11400089265d5df0ee7b38b1d52',
+        'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
+        'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
+        'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',
+        'org.jmock:jmock-legacy:2.8.2:jmock-legacy-2.8.2.jar:f2b985a5c08a9edb7f37612330c058809da3f6a6d63ce792426ebf8ff0d6d31b',
+        'org.jmock:jmock-testjar:2.8.2:jmock-testjar-2.8.2.jar:8900860f72c474e027cf97fe78dcbf154a1aa7fc62b6845c5fb4e4f3c7bc8760',
+        'org.jmock:jmock:2.8.2:jmock-2.8.2.jar:6c73cb4a2e6dbfb61fd99c9a768539c170ab6568e57846bd60dbf19596b65b16',
+        'org.objenesis:objenesis:2.1:objenesis-2.1.jar:c74330cc6b806c804fd37e74487b4fe5d7c2750c5e15fbc6efa13bdee1bdef80',
+        'org.ow2.asm:asm-all:5.2:asm-all-5.2.jar:7fbffbc1db3422e2101689fd88df8384b15817b52b9b2b267b9f6d2511dc198d',
+        'org.ow2.asm:asm:5.0.4:asm-5.0.4.jar:896618ed8ae62702521a78bc7be42b7c491a08e6920a15f89a3ecdec31e9a220',
+    ]
+}
@@ -3,9 +3,10 @@ sourceCompatibility = 1.8
 targetCompatibility = 1.8

 apply plugin: 'ru.vyarus.animalsniffer'
-apply plugin: 'net.ltgt.apt'
 apply plugin: 'idea'
 apply plugin: 'witness'
+apply from: 'witness.gradle'
+apply from: '../dagger.gradle'

 dependencies {
 	implementation project(path: ':bramble-api', configuration: 'default')
@@ -13,9 +14,10 @@ dependencies {
 	implementation 'com.h2database:h2:1.4.192' // The last version that supports Java 1.6
 	implementation 'org.bitlet:weupnp:0.1.4'
 	implementation 'net.i2p.crypto:eddsa:0.2.0'
-	implementation 'org.whispersystems:curve25519-java:0.4.1'
+	implementation 'org.whispersystems:curve25519-java:0.5.0'
+	implementation 'org.briarproject:jtorctl:0.3'

-	apt 'com.google.dagger:dagger-compiler:2.0.2'
+	annotationProcessor 'com.google.dagger:dagger-compiler:2.19'

 	testImplementation project(path: ':bramble-api', configuration: 'testOutput')
 	testImplementation 'org.hsqldb:hsqldb:2.3.5' // The last version that supports Java 1.6
@@ -23,48 +25,13 @@ dependencies {
 	testImplementation "org.jmock:jmock:2.8.2"
 	testImplementation "org.jmock:jmock-junit4:2.8.2"
 	testImplementation "org.jmock:jmock-legacy:2.8.2"
-	testImplementation "org.hamcrest:hamcrest-library:1.3"
-	testImplementation "org.hamcrest:hamcrest-core:1.3"

-	testApt 'com.google.dagger:dagger-compiler:2.0.2'
+	testAnnotationProcessor 'com.google.dagger:dagger-compiler:2.19'

 	signature 'org.codehaus.mojo.signature:java16:1.1@signature'
 }

-dependencyVerification {
-	verify = [
-			'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
-			'com.google.dagger:dagger-compiler:2.0.2:dagger-compiler-2.0.2.jar:b74bc9de063dd4c6400b232231f2ef5056145b8fbecbf5382012007dd1c071b3',
-			'com.google.dagger:dagger-producers:2.0-beta:dagger-producers-2.0-beta.jar:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
-			'com.google.dagger:dagger:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
-			'com.google.guava:guava:18.0:guava-18.0.jar:d664fbfc03d2e5ce9cab2a44fb01f1d0bf9dfebeccc1a473b1f9ea31f79f6f99',
-			'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',
-			'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
-			'junit:junit:4.12:junit-4.12.jar:59721f0805e223d84b90677887d9ff567dc534d7c502ca903c0c2b17f05c116a',
-			'net.i2p.crypto:eddsa:0.2.0:eddsa-0.2.0.jar:a7cb1b85c16e2f0730b9204106929a1d9aaae1df728adc7041a8b8b605692140',
-			'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.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
-			'org.bitlet:weupnp:0.1.4:weupnp-0.1.4.jar:88df7e6504929d00bdb832863761385c68ab92af945b04f0770b126270a444fb',
-			'org.codehaus.mojo.signature:java16:1.1:java16-1.1.signature:53799223a2c98dba2d0add810bed76315460df285c69e4f397ae6098f87dd619',
-			'org.codehaus.mojo:animal-sniffer-ant-tasks:1.16:animal-sniffer-ant-tasks-1.16.jar:890040976fbe2d584619a6a61b1fd2e925b3b5eb342a85eb2762c467c0d64e90',
-			'org.codehaus.mojo:animal-sniffer:1.16:animal-sniffer-1.16.jar:72be8bcc226ba43b937c722a08a07852bfa1b11400089265d5df0ee7b38b1d52',
-			'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
-			'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
-			'org.hsqldb:hsqldb:2.3.5:hsqldb-2.3.5.jar:6676a6977ac98997a80f827ddbd3fe8ca1e0853dad1492512135fd1a222ccfad',
-			'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',
-			'org.jmock:jmock-legacy:2.8.2:jmock-legacy-2.8.2.jar:f2b985a5c08a9edb7f37612330c058809da3f6a6d63ce792426ebf8ff0d6d31b',
-			'org.jmock:jmock-testjar:2.8.2:jmock-testjar-2.8.2.jar:8900860f72c474e027cf97fe78dcbf154a1aa7fc62b6845c5fb4e4f3c7bc8760',
-			'org.jmock:jmock:2.8.2:jmock-2.8.2.jar:6c73cb4a2e6dbfb61fd99c9a768539c170ab6568e57846bd60dbf19596b65b16',
-			'org.objenesis:objenesis:2.1:objenesis-2.1.jar:c74330cc6b806c804fd37e74487b4fe5d7c2750c5e15fbc6efa13bdee1bdef80',
-			'org.ow2.asm:asm-all:5.2:asm-all-5.2.jar:7fbffbc1db3422e2101689fd88df8384b15817b52b9b2b267b9f6d2511dc198d',
-			'org.ow2.asm:asm:5.0.4:asm-5.0.4.jar:896618ed8ae62702521a78bc7be42b7c491a08e6920a15f89a3ecdec31e9a220',
-			'org.whispersystems:curve25519-java:0.4.1:curve25519-java-0.4.1.jar:7dd659d8822c06c3aea1a47f18fac9e5761e29cab8100030b877db445005f03e',
-	]
-}
-
-// needed to make test output available to bramble-j2se
+// needed to make test output available to bramble-java
 configurations {
 	testOutput.extendsFrom(testCompile)
 }
@@ -8,7 +8,7 @@ import org.briarproject.bramble.lifecycle.LifecycleModule;
 import org.briarproject.bramble.plugin.PluginModule;
 import org.briarproject.bramble.properties.PropertiesModule;
 import org.briarproject.bramble.reporting.ReportingModule;
-import org.briarproject.bramble.sync.SyncModule;
+import org.briarproject.bramble.sync.validation.ValidationModule;
 import org.briarproject.bramble.system.SystemModule;
 import org.briarproject.bramble.transport.TransportModule;
 import org.briarproject.bramble.versioning.VersioningModule;
@@ -31,11 +31,11 @@ public interface BrambleCoreEagerSingletons {

 	void inject(ReportingModule.EagerSingletons init);

-	void inject(SyncModule.EagerSingletons init);
-
 	void inject(SystemModule.EagerSingletons init);

 	void inject(TransportModule.EagerSingletons init);

+	void inject(ValidationModule.EagerSingletons init);
+
 	void inject(VersioningModule.EagerSingletons init);
 }
@@ -19,6 +19,7 @@ import org.briarproject.bramble.reporting.ReportingModule;
 import org.briarproject.bramble.settings.SettingsModule;
 import org.briarproject.bramble.socks.SocksModule;
 import org.briarproject.bramble.sync.SyncModule;
+import org.briarproject.bramble.sync.validation.ValidationModule;
 import org.briarproject.bramble.system.SystemModule;
 import org.briarproject.bramble.transport.TransportModule;
 import org.briarproject.bramble.versioning.VersioningModule;
@@ -47,6 +48,7 @@ import dagger.Module;
 		SyncModule.class,
 		SystemModule.class,
 		TransportModule.class,
+		ValidationModule.class,
 		VersioningModule.class
 })
 public class BrambleCoreModule {
@@ -60,9 +62,9 @@ public class BrambleCoreModule {
 		c.inject(new PluginModule.EagerSingletons());
 		c.inject(new PropertiesModule.EagerSingletons());
 		c.inject(new ReportingModule.EagerSingletons());
-		c.inject(new SyncModule.EagerSingletons());
 		c.inject(new SystemModule.EagerSingletons());
 		c.inject(new TransportModule.EagerSingletons());
+		c.inject(new ValidationModule.EagerSingletons());
 		c.inject(new VersioningModule.EagerSingletons());
 	}
 }
@@ -159,6 +159,8 @@ class AccountManagerImpl implements AccountManager {
 	@Override
 	public boolean createAccount(String name, String password) {
 		synchronized (stateChangeLock) {
+			if (hasDatabaseKey())
+				throw new AssertionError("Already have a database key");
 			LocalAuthor localAuthor = identityManager.createLocalAuthor(name);
 			identityManager.registerLocalAuthor(localAuthor);
 			SecretKey key = crypto.generateSecretKey();
@@ -181,6 +183,7 @@ class AccountManagerImpl implements AccountManager {
 			LOG.info("Deleting account");
 			IoUtils.deleteFileOrDir(databaseConfig.getDatabaseKeyDirectory());
 			IoUtils.deleteFileOrDir(databaseConfig.getDatabaseDirectory());
+			databaseKey = null;
 		}
 	}

@@ -0,0 +1,19 @@
+package org.briarproject.bramble.battery;
+
+import org.briarproject.bramble.api.battery.BatteryManager;
+
+import dagger.Module;
+import dagger.Provides;
+
+/**
+ * Provides a default implementation of {@link BatteryManager} for systems
+ * without batteries.
+ */
+@Module
+public class DefaultBatteryManagerModule {
+
+	@Provides
+	BatteryManager provideBatteryManager() {
+		return () -> false;
+	}
+}
@@ -41,7 +41,6 @@ import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_N
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
 import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MAX_PROPERTIES_PER_TRANSPORT;
 import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MAX_PROPERTY_LENGTH;
-import static org.briarproject.bramble.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
 import static org.briarproject.bramble.util.ValidationUtils.checkLength;
 import static org.briarproject.bramble.util.ValidationUtils.checkSize;

@@ -83,13 +82,7 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public void addLocalMessage(Message m, BdfDictionary metadata,
 			boolean shared) throws DbException, FormatException {
-		Transaction txn = db.startTransaction(false);
-		try {
-			addLocalMessage(txn, m, metadata, shared);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
+		db.transaction(false, txn -> addLocalMessage(txn, m, metadata, shared));
 	}

 	@Override
@@ -114,59 +107,31 @@ class ClientHelperImpl implements ClientHelper {

 	@Override
 	public Message getMessage(MessageId m) throws DbException {
-		Message message;
-		Transaction txn = db.startTransaction(true);
-		try {
-			message = getMessage(txn, m);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return message;
+		return db.transactionWithResult(true, txn -> getMessage(txn, m));
 	}

 	@Override
 	public Message getMessage(Transaction txn, MessageId m) throws DbException {
-		byte[] raw = db.getRawMessage(txn, m);
-		if (raw == null) return null;
-		return messageFactory.createMessage(m, raw);
+		return db.getMessage(txn, m);
 	}

 	@Override
 	public BdfList getMessageAsList(MessageId m) throws DbException,
 			FormatException {
-		BdfList list;
-		Transaction txn = db.startTransaction(true);
-		try {
-			list = getMessageAsList(txn, m);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return list;
+		return db.transactionWithResult(true, txn -> getMessageAsList(txn, m));
 	}

 	@Override
 	public BdfList getMessageAsList(Transaction txn, MessageId m)
 			throws DbException, FormatException {
-		byte[] raw = db.getRawMessage(txn, m);
-		if (raw == null) return null;
-		return toList(raw, MESSAGE_HEADER_LENGTH,
-				raw.length - MESSAGE_HEADER_LENGTH);
+		return toList(db.getMessage(txn, m).getBody());
 	}

 	@Override
 	public BdfDictionary getGroupMetadataAsDictionary(GroupId g)
 			throws DbException, FormatException {
-		BdfDictionary dictionary;
-		Transaction txn = db.startTransaction(true);
-		try {
-			dictionary = getGroupMetadataAsDictionary(txn, g);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return dictionary;
+		return db.transactionWithResult(true, txn ->
+				getGroupMetadataAsDictionary(txn, g));
 	}

 	@Override
@@ -179,15 +144,8 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public BdfDictionary getMessageMetadataAsDictionary(MessageId m)
 			throws DbException, FormatException {
-		BdfDictionary dictionary;
-		Transaction txn = db.startTransaction(true);
-		try {
-			dictionary = getMessageMetadataAsDictionary(txn, m);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return dictionary;
+		return db.transactionWithResult(true, txn ->
+				getMessageMetadataAsDictionary(txn, m));
 	}

 	@Override
@@ -200,15 +158,8 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public Map<MessageId, BdfDictionary> getMessageMetadataAsDictionary(
 			GroupId g) throws DbException, FormatException {
-		Map<MessageId, BdfDictionary> map;
-		Transaction txn = db.startTransaction(true);
-		try {
-			map = getMessageMetadataAsDictionary(txn, g);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return map;
+		return db.transactionWithResult(true, txn ->
+				getMessageMetadataAsDictionary(txn, g));
 	}

 	@Override
@@ -225,15 +176,8 @@ class ClientHelperImpl implements ClientHelper {
 	public Map<MessageId, BdfDictionary> getMessageMetadataAsDictionary(
 			GroupId g, BdfDictionary query) throws DbException,
 			FormatException {
-		Map<MessageId, BdfDictionary> map;
-		Transaction txn = db.startTransaction(true);
-		try {
-			map = getMessageMetadataAsDictionary(txn, g, query);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return map;
+		return db.transactionWithResult(true, txn ->
+				getMessageMetadataAsDictionary(txn, g, query));
 	}

 	@Override
@@ -251,13 +195,7 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public void mergeGroupMetadata(GroupId g, BdfDictionary metadata)
 			throws DbException, FormatException {
-		Transaction txn = db.startTransaction(false);
-		try {
-			mergeGroupMetadata(txn, g, metadata);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
+		db.transaction(false, txn -> mergeGroupMetadata(txn, g, metadata));
 	}

 	@Override
@@ -269,13 +207,7 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public void mergeMessageMetadata(MessageId m, BdfDictionary metadata)
 			throws DbException, FormatException {
-		Transaction txn = db.startTransaction(false);
-		try {
-			mergeMessageMetadata(txn, m, metadata);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
+		db.transaction(false, txn -> mergeMessageMetadata(txn, m, metadata));
 	}

 	@Override
@@ -364,9 +296,7 @@ class ClientHelperImpl implements ClientHelper {

 	@Override
 	public BdfList toList(Message m) throws FormatException {
-		byte[] raw = m.getRaw();
-		return toList(raw, MESSAGE_HEADER_LENGTH,
-				raw.length - MESSAGE_HEADER_LENGTH);
+		return toList(m.getBody());
 	}

 	@Override
@@ -13,7 +13,6 @@ import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.db.ContactExistsException;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
@@ -158,7 +157,8 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 				streamWriterFactory.createContactExchangeStreamWriter(out,
 						alice ? aliceHeaderKey : bobHeaderKey);
 		RecordWriter recordWriter =
-				recordWriterFactory.createRecordWriter(streamWriter.getOutputStream());
+				recordWriterFactory
+						.createRecordWriter(streamWriter.getOutputStream());

 		// Derive the nonces to be signed
 		byte[] aliceNonce = crypto.mac(ALICE_NONCE_LABEL, masterSecret,
@@ -287,19 +287,14 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 	private ContactId addContact(Author remoteAuthor, long timestamp,
 			Map<TransportId, TransportProperties> remoteProperties)
 			throws DbException {
-		ContactId contactId;
-		Transaction txn = db.startTransaction(false);
-		try {
-			contactId = contactManager.addContact(txn, remoteAuthor,
+		return db.transactionWithResult(false, txn -> {
+			ContactId contactId = contactManager.addContact(txn, remoteAuthor,
 					localAuthor.getId(), masterSecret, timestamp, alice,
 					true, true);
 			transportPropertyManager.addRemoteProperties(txn, contactId,
 					remoteProperties);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
 			return contactId;
+		});
 	}

 	private void tryToClose(DuplexTransportConnection conn) {
@@ -10,6 +10,9 @@ import org.briarproject.bramble.api.db.NoSuchContactException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.identity.AuthorInfo;
+import org.briarproject.bramble.api.identity.IdentityManager;
+import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.transport.KeyManager;

@@ -18,21 +21,32 @@ import java.util.Collection;
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;

+import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 import javax.inject.Inject;

+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
+import static org.briarproject.bramble.api.identity.AuthorInfo.Status.OURSELVES;
+import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNKNOWN;
+import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNVERIFIED;
+import static org.briarproject.bramble.api.identity.AuthorInfo.Status.VERIFIED;
+import static org.briarproject.bramble.util.StringUtils.toUtf8;
+
@ThreadSafe
@NotNullByDefault
 class ContactManagerImpl implements ContactManager {

 	private final DatabaseComponent db;
 	private final KeyManager keyManager;
+	private final IdentityManager identityManager;
 	private final List<ContactHook> hooks;

 	@Inject
-	ContactManagerImpl(DatabaseComponent db, KeyManager keyManager) {
+	ContactManagerImpl(DatabaseComponent db, KeyManager keyManager,
+			IdentityManager identityManager) {
 		this.db = db;
 		this.keyManager = keyManager;
+		this.identityManager = identityManager;
 		hooks = new CopyOnWriteArrayList<>();
 	}

@@ -65,42 +79,21 @@ class ContactManagerImpl implements ContactManager {
 	public ContactId addContact(Author remote, AuthorId local, SecretKey master,
 			long timestamp, boolean alice, boolean verified, boolean active)
 			throws DbException {
-		ContactId c;
-		Transaction txn = db.startTransaction(false);
-		try {
-			c = addContact(txn, remote, local, master, timestamp, alice,
-					verified, active);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return c;
+		return db.transactionWithResult(false, txn ->
+				addContact(txn, remote, local, master, timestamp, alice,
+						verified, active));
 	}

 	@Override
 	public Contact getContact(ContactId c) throws DbException {
-		Contact contact;
-		Transaction txn = db.startTransaction(true);
-		try {
-			contact = db.getContact(txn, c);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return contact;
+		return db.transactionWithResult(true, txn -> db.getContact(txn, c));
 	}

 	@Override
 	public Contact getContact(AuthorId remoteAuthorId, AuthorId localAuthorId)
 			throws DbException {
-		Transaction txn = db.startTransaction(true);
-		try {
-			Contact c = getContact(txn, remoteAuthorId, localAuthorId);
-			db.commitTransaction(txn);
-			return c;
-		} finally {
-			db.endTransaction(txn);
-		}
+		return db.transactionWithResult(true, txn ->
+				getContact(txn, remoteAuthorId, localAuthorId));
 	}

 	@Override
@@ -118,14 +111,8 @@ class ContactManagerImpl implements ContactManager {

 	@Override
 	public Collection<Contact> getActiveContacts() throws DbException {
-		Collection<Contact> contacts;
-		Transaction txn = db.startTransaction(true);
-		try {
-			contacts = db.getContacts(txn);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
+		Collection<Contact> contacts =
+				db.transactionWithResult(true, db::getContacts);
 		List<Contact> active = new ArrayList<>(contacts.size());
 		for (Contact c : contacts) if (c.isActive()) active.add(c);
 		return active;
@@ -133,13 +120,7 @@ class ContactManagerImpl implements ContactManager {

 	@Override
 	public void removeContact(ContactId c) throws DbException {
-		Transaction txn = db.startTransaction(false);
-		try {
-			removeContact(txn, c);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
+		db.transaction(false, txn -> removeContact(txn, c));
 	}

 	@Override
@@ -148,6 +129,23 @@ class ContactManagerImpl implements ContactManager {
 		db.setContactActive(txn, c, active);
 	}

+	@Override
+	public void setContactAlias(Transaction txn, ContactId c,
+			@Nullable String alias) throws DbException {
+		if (alias != null) {
+			int aliasLength = toUtf8(alias).length;
+			if (aliasLength == 0 || aliasLength > MAX_AUTHOR_NAME_LENGTH)
+				throw new IllegalArgumentException();
+		}
+		db.setContactAlias(txn, c, alias);
+	}
+
+	@Override
+	public void setContactAlias(ContactId c, @Nullable String alias)
+			throws DbException {
+		db.transaction(false, txn -> setContactAlias(txn, c, alias));
+	}
+
 	@Override
 	public boolean contactExists(Transaction txn, AuthorId remoteAuthorId,
 			AuthorId localAuthorId) throws DbException {
@@ -157,15 +155,8 @@ class ContactManagerImpl implements ContactManager {
 	@Override
 	public boolean contactExists(AuthorId remoteAuthorId,
 			AuthorId localAuthorId) throws DbException {
-		boolean exists;
-		Transaction txn = db.startTransaction(true);
-		try {
-			exists = contactExists(txn, remoteAuthorId, localAuthorId);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return exists;
+		return db.transactionWithResult(true, txn ->
+				contactExists(txn, remoteAuthorId, localAuthorId));
 	}

 	@Override
@@ -176,4 +167,23 @@ class ContactManagerImpl implements ContactManager {
 		db.removeContact(txn, c);
 	}

+	@Override
+	public AuthorInfo getAuthorInfo(AuthorId a) throws DbException {
+		return db.transactionWithResult(true, txn -> getAuthorInfo(txn, a));
+	}
+
+	@Override
+	public AuthorInfo getAuthorInfo(Transaction txn, AuthorId authorId)
+			throws DbException {
+		LocalAuthor localAuthor = identityManager.getLocalAuthor(txn);
+		if (localAuthor.getId().equals(authorId))
+			return new AuthorInfo(OURSELVES);
+		Collection<Contact> contacts = db.getContactsByAuthorId(txn, authorId);
+		if (contacts.isEmpty()) return new AuthorInfo(UNKNOWN);
+		if (contacts.size() > 1) throw new AssertionError();
+		Contact c = contacts.iterator().next();
+		if (c.isVerified()) return new AuthorInfo(VERIFIED, c.getAlias());
+		else return new AuthorInfo(UNVERIFIED, c.getAlias());
+	}
+
 }
@@ -29,6 +29,7 @@ import static org.briarproject.bramble.data.Types.STRING_16;
 import static org.briarproject.bramble.data.Types.STRING_32;
 import static org.briarproject.bramble.data.Types.STRING_8;
 import static org.briarproject.bramble.data.Types.TRUE;
+import static org.briarproject.bramble.util.StringUtils.fromUtf8;

@NotThreadSafe
@NotNullByDefault
@@ -253,7 +254,7 @@ class BdfReaderImpl implements BdfReader {
 		if (length < 0 || length > maxBufferSize) throw new FormatException();
 		if (length == 0) return "";
 		readIntoBuffer(length);
-		return new String(buf, 0, length, "UTF-8");
+		return fromUtf8(buf, 0, length);
 	}

 	private int readStringLength() throws IOException {
@@ -6,6 +6,7 @@ import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.DataTooNewException;
 import org.briarproject.bramble.api.db.DataTooOldException;
 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.MessageDeletedException;
 import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.MigrationListener;
 import org.briarproject.bramble.api.identity.Author;
@@ -21,7 +22,7 @@ import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.MessageStatus;
-import org.briarproject.bramble.api.sync.ValidationManager.State;
+import org.briarproject.bramble.api.sync.validation.MessageState;
 import org.briarproject.bramble.api.transport.KeySet;
 import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
@@ -105,7 +106,7 @@ interface Database<T> {
 	 * @param sender the contact from whom the message was received, or null
 	 * if the message was created locally.
 	 */
-	void addMessage(T txn, Message m, State state, boolean shared,
+	void addMessage(T txn, Message m, MessageState state, boolean shared,
 			@Nullable ContactId sender) throws DbException;

 	/**
@@ -113,7 +114,7 @@ interface Database<T> {
 	 * in the given state.
 	 */
 	void addMessageDependency(T txn, Message dependent, MessageId dependency,
-			State dependentState) throws DbException;
+			MessageState dependentState) throws DbException;

 	/**
 	 * Records that a message has been offered by the given contact.
@@ -297,14 +298,23 @@ interface Database<T> {
 	 */
 	Collection<LocalAuthor> getLocalAuthors(T txn) throws DbException;

+	/**
+	 * Returns the message with the given ID.
+	 * <p/>
+	 * Read-only.
+	 *
+	 * @throws MessageDeletedException if the message has been deleted
+	 */
+	Message getMessage(T txn, MessageId m) throws DbException;
+
 	/**
 	 * Returns the IDs and states of all dependencies of the given message.
 	 * For missing dependencies and dependencies in other groups, the state
-	 * {@link State UNKNOWN} is returned.
+	 * {@link MessageState UNKNOWN} is returned.
 	 * <p/>
 	 * Read-only.
 	 */
-	Map<MessageId, State> getMessageDependencies(T txn, MessageId m)
+	Map<MessageId, MessageState> getMessageDependencies(T txn, MessageId m)
 			throws DbException;

 	/**
@@ -314,7 +324,7 @@ interface Database<T> {
 	 * <p/>
 	 * Read-only.
 	 */
-	Map<MessageId, State> getMessageDependents(T txn, MessageId m)
+	Map<MessageId, MessageState> getMessageDependents(T txn, MessageId m)
 			throws DbException;

 	/**
@@ -373,7 +383,7 @@ interface Database<T> {
 	 * <p/>
 	 * Read-only.
 	 */
-	State getMessageState(T txn, MessageId m) throws DbException;
+	MessageState getMessageState(T txn, MessageId m) throws DbException;

 	/**
 	 * Returns the status of all delivered messages in the given group with
@@ -411,7 +421,7 @@ interface Database<T> {
 	 * Read-only.
 	 */
 	Collection<MessageId> getMessagesToOffer(T txn, ContactId c,
-			int maxMessages) throws DbException;
+			int maxMessages, int maxLatency) throws DbException;

 	/**
 	 * Returns the IDs of some messages that are eligible to be requested from
@@ -428,8 +438,8 @@ interface Database<T> {
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<MessageId> getMessagesToSend(T txn, ContactId c, int maxLength)
-			throws DbException;
+	Collection<MessageId> getMessagesToSend(T txn, ContactId c, int maxLength,
+			int maxLatency) throws DbException;

 	/**
 	 * Returns the IDs of any messages that need to be validated.
@@ -464,15 +474,6 @@ interface Database<T> {
 	 */
 	long getNextSendTime(T txn, ContactId c) throws DbException;

-	/**
-	 * Returns the message with the given ID, in serialised form, or null if
-	 * the message has been deleted.
-	 * <p/>
-	 * Read-only.
-	 */
-	@Nullable
-	byte[] getRawMessage(T txn, MessageId m) throws DbException;
-
 	/**
 	 * Returns the IDs of some messages that are eligible to be sent to the
 	 * given contact and have been requested by the contact, up to the given
@@ -481,7 +482,7 @@ interface Database<T> {
 	 * Read-only.
 	 */
 	Collection<MessageId> getRequestedMessagesToSend(T txn, ContactId c,
-			int maxLength) throws DbException;
+			int maxLength, int maxLatency) throws DbException;

 	/**
 	 * Returns all settings in the given namespace.
@@ -615,6 +616,12 @@ interface Database<T> {
 	void setContactActive(T txn, ContactId c, boolean active)
 			throws DbException;

+	/**
+	 * Sets an alias name for a contact.
+	 */
+	void setContactAlias(T txn, ContactId c, @Nullable String alias)
+			throws DbException;
+
 	/**
 	 * Sets the given group's visibility to the given contact to either
 	 * {@link Visibility VISIBLE} or {@link Visibility SHARED}.
@@ -630,7 +637,8 @@ interface Database<T> {
 	/**
 	 * Sets the validation and delivery state of the given message.
 	 */
-	void setMessageState(T txn, MessageId m, State state) throws DbException;
+	void setMessageState(T txn, MessageId m, MessageState state)
+			throws DbException;

 	/**
 	 * Sets the reordering window for the given key set and transport in the
@@ -646,11 +654,11 @@ interface Database<T> {
 			throws DbException;

 	/**
-	 * Updates the transmission count and expiry time of the given message
-	 * with respect to the given contact, using the latency of the transport
-	 * over which it was sent.
+	 * Updates the transmission count, expiry time and estimated time of arrival
+	 * of the given message with respect to the given contact, using the latency
+	 * of the transport over which it was sent.
 	 */
-	void updateExpiryTime(T txn, ContactId c, MessageId m, int maxLatency)
+	void updateExpiryTimeAndEta(T txn, ContactId c, MessageId m, int maxLatency)
 			throws DbException;

 	/**
@@ -9,7 +9,9 @@ import org.briarproject.bramble.api.contact.event.ContactVerifiedEvent;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.ContactExistsException;
 import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.DbCallable;
 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.DbRunnable;
 import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.MigrationListener;
 import org.briarproject.bramble.api.db.NoSuchContactException;
@@ -17,6 +19,7 @@ import org.briarproject.bramble.api.db.NoSuchGroupException;
 import org.briarproject.bramble.api.db.NoSuchLocalAuthorException;
 import org.briarproject.bramble.api.db.NoSuchMessageException;
 import org.briarproject.bramble.api.db.NoSuchTransportException;
+import org.briarproject.bramble.api.db.NullableDbCallable;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
@@ -40,7 +43,6 @@ import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.MessageStatus;
 import org.briarproject.bramble.api.sync.Offer;
 import org.briarproject.bramble.api.sync.Request;
-import org.briarproject.bramble.api.sync.ValidationManager.State;
 import org.briarproject.bramble.api.sync.event.GroupAddedEvent;
 import org.briarproject.bramble.api.sync.event.GroupRemovedEvent;
 import org.briarproject.bramble.api.sync.event.GroupVisibilityUpdatedEvent;
@@ -52,6 +54,7 @@ import org.briarproject.bramble.api.sync.event.MessageToAckEvent;
 import org.briarproject.bramble.api.sync.event.MessageToRequestEvent;
 import org.briarproject.bramble.api.sync.event.MessagesAckedEvent;
 import org.briarproject.bramble.api.sync.event.MessagesSentEvent;
+import org.briarproject.bramble.api.sync.validation.MessageState;
 import org.briarproject.bramble.api.transport.KeySet;
 import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
@@ -72,8 +75,8 @@ import javax.inject.Inject;
 import static java.util.logging.Level.WARNING;
 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.ValidationManager.State.DELIVERED;
-import static org.briarproject.bramble.api.sync.ValidationManager.State.UNKNOWN;
+import static org.briarproject.bramble.api.sync.validation.MessageState.DELIVERED;
+import static org.briarproject.bramble.api.sync.validation.MessageState.UNKNOWN;
 import static org.briarproject.bramble.db.DatabaseConstants.MAX_OFFERED_MESSAGES;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.logException;
@@ -166,6 +169,45 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			for (Event e : transaction.getEvents()) eventBus.broadcast(e);
 	}

+	@Override
+	public <E extends Exception> void transaction(boolean readOnly,
+			DbRunnable<E> task) throws DbException, E {
+		Transaction txn = startTransaction(readOnly);
+		try {
+			task.run(txn);
+			commitTransaction(txn);
+		} finally {
+			endTransaction(txn);
+		}
+	}
+
+	@Override
+	public <R, E extends Exception> R transactionWithResult(boolean readOnly,
+			DbCallable<R, E> task) throws DbException, E {
+		Transaction txn = startTransaction(readOnly);
+		try {
+			R result = task.call(txn);
+			commitTransaction(txn);
+			return result;
+		} finally {
+			endTransaction(txn);
+		}
+	}
+
+	@Override
+	public <R, E extends Exception> R transactionWithNullableResult(
+			boolean readOnly, NullableDbCallable<R, E> task)
+			throws DbException, E {
+		Transaction txn = startTransaction(readOnly);
+		try {
+			R result = task.call(txn);
+			commitTransaction(txn);
+			return result;
+		} finally {
+			endTransaction(txn);
+		}
+	}
+
 	private T unbox(Transaction transaction) {
 		if (transaction.isCommitted()) throw new IllegalStateException();
 		return txnClass.cast(transaction.unbox());
@@ -307,17 +349,18 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {

 	@Nullable
 	@Override
-	public Collection<byte[]> generateBatch(Transaction transaction,
+	public Collection<Message> generateBatch(Transaction transaction,
 			ContactId c, int maxLength, int maxLatency) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
 		if (!db.containsContact(txn, c))
 			throw new NoSuchContactException();
-		Collection<MessageId> ids = db.getMessagesToSend(txn, c, maxLength);
-		List<byte[]> messages = new ArrayList<>(ids.size());
+		Collection<MessageId> ids =
+				db.getMessagesToSend(txn, c, maxLength, maxLatency);
+		List<Message> messages = new ArrayList<>(ids.size());
 		for (MessageId m : ids) {
-			messages.add(db.getRawMessage(txn, m));
-			db.updateExpiryTime(txn, c, m, maxLatency);
+			messages.add(db.getMessage(txn, m));
+			db.updateExpiryTimeAndEta(txn, c, m, maxLatency);
 		}
 		if (ids.isEmpty()) return null;
 		db.lowerRequestedFlag(txn, c, ids);
@@ -333,9 +376,11 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		T txn = unbox(transaction);
 		if (!db.containsContact(txn, c))
 			throw new NoSuchContactException();
-		Collection<MessageId> ids = db.getMessagesToOffer(txn, c, maxMessages);
+		Collection<MessageId> ids =
+				db.getMessagesToOffer(txn, c, maxMessages, maxLatency);
 		if (ids.isEmpty()) return null;
-		for (MessageId m : ids) db.updateExpiryTime(txn, c, m, maxLatency);
+		for (MessageId m : ids)
+			db.updateExpiryTimeAndEta(txn, c, m, maxLatency);
 		return new Offer(ids);
 	}

@@ -356,18 +401,18 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {

 	@Nullable
 	@Override
-	public Collection<byte[]> generateRequestedBatch(Transaction transaction,
+	public Collection<Message> generateRequestedBatch(Transaction transaction,
 			ContactId c, int maxLength, int maxLatency) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
 		if (!db.containsContact(txn, c))
 			throw new NoSuchContactException();
-		Collection<MessageId> ids = db.getRequestedMessagesToSend(txn, c,
-				maxLength);
-		List<byte[]> messages = new ArrayList<>(ids.size());
+		Collection<MessageId> ids =
+				db.getRequestedMessagesToSend(txn, c, maxLength, maxLatency);
+		List<Message> messages = new ArrayList<>(ids.size());
 		for (MessageId m : ids) {
-			messages.add(db.getRawMessage(txn, m));
-			db.updateExpiryTime(txn, c, m, maxLatency);
+			messages.add(db.getMessage(txn, m));
+			db.updateExpiryTimeAndEta(txn, c, m, maxLatency);
 		}
 		if (ids.isEmpty()) return null;
 		db.lowerRequestedFlag(txn, c, ids);
@@ -457,6 +502,15 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.getLocalAuthors(txn);
 	}

+	@Override
+	public Message getMessage(Transaction transaction, MessageId m)
+			throws DbException {
+		T txn = unbox(transaction);
+		if (!db.containsMessage(txn, m))
+			throw new NoSuchMessageException();
+		return db.getMessage(txn, m);
+	}
+
 	@Override
 	public Collection<MessageId> getMessageIds(Transaction transaction,
 			GroupId g) throws DbException {
@@ -487,16 +541,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.getMessagesToShare(txn);
 	}

-	@Nullable
-	@Override
-	public byte[] getRawMessage(Transaction transaction, MessageId m)
-			throws DbException {
-		T txn = unbox(transaction);
-		if (!db.containsMessage(txn, m))
-			throw new NoSuchMessageException();
-		return db.getRawMessage(txn, m);
-	}
-
 	@Override
 	public Map<MessageId, Metadata> getMessageMetadata(Transaction transaction,
 			GroupId g) throws DbException {
@@ -535,7 +579,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}

 	@Override
-	public State getMessageState(Transaction transaction, MessageId m)
+	public MessageState getMessageState(Transaction transaction, MessageId m)
 			throws DbException {
 		T txn = unbox(transaction);
 		if (!db.containsMessage(txn, m))
@@ -575,8 +619,8 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}

 	@Override
-	public Map<MessageId, State> getMessageDependencies(Transaction transaction,
-			MessageId m) throws DbException {
+	public Map<MessageId, MessageState> getMessageDependencies(
+			Transaction transaction, MessageId m) throws DbException {
 		T txn = unbox(transaction);
 		if (!db.containsMessage(txn, m))
 			throw new NoSuchMessageException();
@@ -584,8 +628,8 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}

 	@Override
-	public Map<MessageId, State> getMessageDependents(Transaction transaction,
-			MessageId m) throws DbException {
+	public Map<MessageId, MessageState> getMessageDependents(
+			Transaction transaction, MessageId m) throws DbException {
 		T txn = unbox(transaction);
 		if (!db.containsMessage(txn, m))
 			throw new NoSuchMessageException();
@@ -656,7 +700,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		merged.putAll(s);
 		if (!merged.equals(old)) {
 			db.mergeSettings(txn, s, namespace);
-			transaction.attach(new SettingsUpdatedEvent(namespace));
+			transaction.attach(new SettingsUpdatedEvent(namespace, merged));
 		}
 	}

@@ -830,6 +874,16 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		transaction.attach(new ContactStatusChangedEvent(c, active));
 	}

+	@Override
+	public void setContactAlias(Transaction transaction, ContactId c,
+			@Nullable String alias) throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsContact(txn, c))
+			throw new NoSuchContactException();
+		db.setContactAlias(txn, c, alias);
+	}
+
 	@Override
 	public void setGroupVisibility(Transaction transaction, ContactId c,
 			GroupId g, Visibility v) throws DbException {
@@ -856,14 +910,15 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		if (!db.containsMessage(txn, m))
 			throw new NoSuchMessageException();
 		if (db.getMessageState(txn, m) != DELIVERED)
-			throw new IllegalArgumentException("Shared undelivered message");
+			throw new IllegalArgumentException(
+					"Shared undelivered message");
 		db.setMessageShared(txn, m);
 		transaction.attach(new MessageSharedEvent(m));
 	}

 	@Override
 	public void setMessageState(Transaction transaction, MessageId m,
-			State state) throws DbException {
+			MessageState state) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
 		if (!db.containsMessage(txn, m))
@@ -880,7 +935,8 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		T txn = unbox(transaction);
 		if (!db.containsMessage(txn, dependent.getId()))
 			throw new NoSuchMessageException();
-		State dependentState = db.getMessageState(txn, dependent.getId());
+		MessageState dependentState =
+				db.getMessageState(txn, dependent.getId());
 		for (MessageId dependency : dependencies) {
 			db.addMessageDependency(txn, dependent, dependency, dependentState);
 		}
@@ -914,7 +970,8 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		T txn = unbox(transaction);
 		for (KeySet ks : keys) {
 			TransportId t = ks.getTransportKeys().getTransportId();
-			if (db.containsTransport(txn, t)) db.updateTransportKeys(txn, ks);
+			if (db.containsTransport(txn, t))
+				db.updateTransportKeys(txn, ks);
 		}
 	}
 }
@@ -2,6 +2,8 @@ package org.briarproject.bramble.db;

 import org.briarproject.bramble.api.settings.Settings;

+import static java.util.concurrent.TimeUnit.DAYS;
+
 interface DatabaseConstants {

 	/**
@@ -23,4 +25,16 @@ interface DatabaseConstants {
 	 */
 	String SCHEMA_VERSION_KEY = "schemaVersion";

+	/**
+	 * The {@link Settings} key under which the time of the last database
+	 * compaction is stored.
+	 */
+	String LAST_COMPACTED_KEY = "lastCompacted";
+
+	/**
+	 * The maximum time between database compactions in milliseconds. When the
+	 * database is opened it will be compacted if more than this amount of time
+	 * has passed since the last compaction.
+	 */
+	long MAX_COMPACTION_INTERVAL_MS = DAYS.toMillis(30);
 }
@@ -4,6 +4,7 @@ import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseConfig;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.lifecycle.ShutdownManager;
+import org.briarproject.bramble.api.sync.MessageFactory;
 import org.briarproject.bramble.api.system.Clock;

 import java.sql.Connection;
@@ -18,8 +19,9 @@ public class DatabaseModule {

 	@Provides
 	@Singleton
-	Database<Connection> provideDatabase(DatabaseConfig config, Clock clock) {
-		return new H2Database(config, clock);
+	Database<Connection> provideDatabase(DatabaseConfig config,
+			MessageFactory messageFactory, Clock clock) {
+		return new H2Database(config, messageFactory, clock);
 	}

 	@Provides
@@ -0,0 +1,34 @@
+package org.briarproject.bramble.db;
+
+class DatabaseTypes {
+
+	private final String hashType, secretType, binaryType;
+	private final String counterType, stringType;
+
+	public DatabaseTypes(String hashType, String secretType, String binaryType,
+			String counterType, String stringType) {
+		this.hashType = hashType;
+		this.secretType = secretType;
+		this.binaryType = binaryType;
+		this.counterType = counterType;
+		this.stringType = stringType;
+	}
+
+	/**
+	 * Replaces database type placeholders in a statement with the actual types.
+	 * These placeholders are currently supported:
+	 * <li> _HASH
+	 * <li> _SECRET
+	 * <li> _BINARY
+	 * <li> _COUNTER
+	 * <li> _STRING
+	 */
+	String replaceTypes(String s) {
+		s = s.replaceAll("_HASH", hashType);
+		s = s.replaceAll("_SECRET", secretType);
+		s = s.replaceAll("_BINARY", binaryType);
+		s = s.replaceAll("_COUNTER", counterType);
+		s = s.replaceAll("_STRING", stringType);
+		return s;
+	}
+}
@@ -5,6 +5,7 @@ import org.briarproject.bramble.api.db.DatabaseConfig;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.MigrationListener;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.MessageFactory;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.util.StringUtils;

@@ -12,6 +13,7 @@ import java.io.File;
 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;
+import java.sql.Statement;
 import java.util.Properties;

 import javax.annotation.Nullable;
@@ -28,6 +30,8 @@ class H2Database extends JdbcDatabase {
 	private static final String BINARY_TYPE = "BINARY";
 	private static final String COUNTER_TYPE = "INT NOT NULL AUTO_INCREMENT";
 	private static final String STRING_TYPE = "VARCHAR";
+	private static final DatabaseTypes dbTypes = new DatabaseTypes(HASH_TYPE,
+			SECRET_TYPE, BINARY_TYPE, COUNTER_TYPE, STRING_TYPE);

 	private final DatabaseConfig config;
 	private final String url;
@@ -36,9 +40,9 @@ class H2Database extends JdbcDatabase {
 	private volatile SecretKey key = null;

 	@Inject
-	H2Database(DatabaseConfig config, Clock clock) {
-		super(HASH_TYPE, SECRET_TYPE, BINARY_TYPE, COUNTER_TYPE, STRING_TYPE,
-				clock);
+	H2Database(DatabaseConfig config, MessageFactory messageFactory,
+			Clock clock) {
+		super(dbTypes, messageFactory, clock);
 		this.config = config;
 		File dir = config.getDatabaseDirectory();
 		String path = new File(dir, "db").getAbsolutePath();
@@ -104,4 +108,22 @@ class H2Database extends JdbcDatabase {
 	String getUrl() {
 		return url;
 	}
+
+	@Override
+	protected void compactAndClose() throws DbException {
+		Connection c = null;
+		Statement s = null;
+		try {
+			c = createConnection();
+			closeAllConnections();
+			s = c.createStatement();
+			s.execute("SHUTDOWN COMPACT");
+			s.close();
+			c.close();
+		} catch (SQLException e) {
+			tryToClose(s);
+			tryToClose(c);
+			throw new DbException(e);
+		}
+	}
 }
@@ -5,6 +5,7 @@ import org.briarproject.bramble.api.db.DatabaseConfig;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.MigrationListener;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.MessageFactory;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.util.StringUtils;

@@ -29,6 +30,8 @@ class HyperSqlDatabase extends JdbcDatabase {
 	private static final String COUNTER_TYPE =
 			"INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY(START WITH 1)";
 	private static final String STRING_TYPE = "VARCHAR";
+	private static final DatabaseTypes dbTypes = new DatabaseTypes(HASH_TYPE,
+			SECRET_TYPE, BINARY_TYPE, COUNTER_TYPE, STRING_TYPE);

 	private final DatabaseConfig config;
 	private final String url;
@@ -37,9 +40,9 @@ class HyperSqlDatabase extends JdbcDatabase {
 	private volatile SecretKey key = null;

 	@Inject
-	HyperSqlDatabase(DatabaseConfig config, Clock clock) {
-		super(HASH_TYPE, SECRET_TYPE, BINARY_TYPE, COUNTER_TYPE, STRING_TYPE,
-				clock);
+	HyperSqlDatabase(DatabaseConfig config, MessageFactory messageFactory,
+			Clock clock) {
+		super(dbTypes, messageFactory, clock);
 		this.config = config;
 		File dir = config.getDatabaseDirectory();
 		String path = new File(dir, "db").getAbsolutePath();
@@ -59,20 +62,24 @@ class HyperSqlDatabase extends JdbcDatabase {

 	@Override
 	public void close() throws DbException {
+		Connection c = null;
+		Statement s = null;
 		try {
 			super.closeAllConnections();
-			Connection c = createConnection();
-			Statement s = c.createStatement();
+			c = createConnection();
+			s = c.createStatement();
 			s.executeQuery("SHUTDOWN");
 			s.close();
 			c.close();
 		} catch (SQLException e) {
+			tryToClose(s);
+			tryToClose(c);
 			throw new DbException(e);
 		}
 	}

 	@Override
-	public long getFreeSpace() throws DbException {
+	public long getFreeSpace() {
 		File dir = config.getDatabaseDirectory();
 		long maxSize = config.getMaxSize();
 		long free = dir.getFreeSpace();
@@ -102,4 +109,22 @@ class HyperSqlDatabase extends JdbcDatabase {
 		String hex = StringUtils.toHexString(key.getBytes());
 		return DriverManager.getConnection(url + ";crypt_key=" + hex);
 	}
+
+	@Override
+	protected void compactAndClose() throws DbException {
+		Connection c = null;
+		Statement s = null;
+		try {
+			super.closeAllConnections();
+			c = createConnection();
+			s = c.createStatement();
+			s.executeQuery("SHUTDOWN COMPACT");
+			s.close();
+			c.close();
+		} catch (SQLException e) {
+			tryToClose(s);
+			tryToClose(c);
+			throw new DbException(e);
+		}
+	}
 }
@@ -7,6 +7,7 @@ import org.briarproject.bramble.api.db.DataTooNewException;
 import org.briarproject.bramble.api.db.DataTooOldException;
 import org.briarproject.bramble.api.db.DbClosedException;
 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.db.MigrationListener;
 import org.briarproject.bramble.api.identity.Author;
@@ -20,9 +21,10 @@ import org.briarproject.bramble.api.sync.Group;
 import org.briarproject.bramble.api.sync.Group.Visibility;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.sync.MessageFactory;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.MessageStatus;
-import org.briarproject.bramble.api.sync.ValidationManager.State;
+import org.briarproject.bramble.api.sync.validation.MessageState;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.transport.IncomingKeys;
 import org.briarproject.bramble.api.transport.KeySet;
@@ -36,6 +38,7 @@ import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -53,20 +56,25 @@ import java.util.logging.Logger;
 import javax.annotation.Nullable;

 import static java.sql.Types.INTEGER;
-import static java.util.Collections.singletonList;
+import static java.sql.Types.VARCHAR;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.api.db.Metadata.REMOVE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
 import static org.briarproject.bramble.api.sync.Group.Visibility.VISIBLE;
-import static org.briarproject.bramble.api.sync.ValidationManager.State.DELIVERED;
-import static org.briarproject.bramble.api.sync.ValidationManager.State.PENDING;
-import static org.briarproject.bramble.api.sync.ValidationManager.State.UNKNOWN;
+import static org.briarproject.bramble.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
+import static org.briarproject.bramble.api.sync.validation.MessageState.DELIVERED;
+import static org.briarproject.bramble.api.sync.validation.MessageState.PENDING;
+import static org.briarproject.bramble.api.sync.validation.MessageState.UNKNOWN;
 import static org.briarproject.bramble.db.DatabaseConstants.DB_SETTINGS_NAMESPACE;
+import static org.briarproject.bramble.db.DatabaseConstants.LAST_COMPACTED_KEY;
+import static org.briarproject.bramble.db.DatabaseConstants.MAX_COMPACTION_INTERVAL_MS;
 import static org.briarproject.bramble.db.DatabaseConstants.SCHEMA_VERSION_KEY;
 import static org.briarproject.bramble.db.ExponentialBackoff.calculateExpiry;
+import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.logException;
+import static org.briarproject.bramble.util.LogUtils.now;

 /**
 * A generic database implementation that can be used with any JDBC-compatible
@@ -76,7 +84,7 @@ import static org.briarproject.bramble.util.LogUtils.logException;
 abstract class JdbcDatabase implements Database<Connection> {

 	// Package access for testing
-	static final int CODE_SCHEMA_VERSION = 39;
+	static final int CODE_SCHEMA_VERSION = 41;

 	// Rotation period offsets for incoming transport keys
 	private static final int OFFSET_PREV = -1;
@@ -106,6 +114,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " authorId _HASH NOT NULL,"
 					+ " formatVersion INT NOT NULL,"
 					+ " name _STRING NOT NULL,"
+					+ " alias _STRING," // Null if no alias exists
 					+ " publicKey _BINARY NOT NULL,"
 					+ " localAuthorId _HASH NOT NULL,"
 					+ " verified BOOLEAN NOT NULL,"
@@ -216,6 +225,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " requested BOOLEAN NOT NULL,"
 					+ " expiry BIGINT NOT NULL,"
 					+ " txCount INT NOT NULL,"
+					+ " eta BIGINT NOT NULL,"
 					+ " PRIMARY KEY (messageId, contactId),"
 					+ " FOREIGN KEY (messageId)"
 					+ " REFERENCES messages (messageId)"
@@ -302,9 +312,9 @@ abstract class JdbcDatabase implements Database<Connection> {
 			Logger.getLogger(JdbcDatabase.class.getName());

 	// Different database libraries use different names for certain types
-	private final String hashType, secretType, binaryType;
-	private final String counterType, stringType;
+	private final MessageFactory messageFactory;
 	private final Clock clock;
+	private final DatabaseTypes dbTypes;

 	// Locking: connectionsLock
 	private final LinkedList<Connection> connections = new LinkedList<>();
@@ -312,19 +322,17 @@ abstract class JdbcDatabase implements Database<Connection> {
 	private int openConnections = 0; // Locking: connectionsLock
 	private boolean closed = false; // Locking: connectionsLock

-	@Nullable
 	protected abstract Connection createConnection() throws SQLException;

+	protected abstract void compactAndClose() throws DbException;
+
 	private final Lock connectionsLock = new ReentrantLock();
 	private final Condition connectionsChanged = connectionsLock.newCondition();

-	JdbcDatabase(String hashType, String secretType, String binaryType,
-			String counterType, String stringType, Clock clock) {
-		this.hashType = hashType;
-		this.secretType = secretType;
-		this.binaryType = binaryType;
-		this.counterType = counterType;
-		this.stringType = stringType;
+	JdbcDatabase(DatabaseTypes databaseTypes, MessageFactory messageFactory,
+			Clock clock) {
+		this.dbTypes = databaseTypes;
+		this.messageFactory = messageFactory;
 		this.clock = clock;
 	}

@@ -337,13 +345,16 @@ abstract class JdbcDatabase implements Database<Connection> {
 			throw new DbException(e);
 		}
 		// Open the database and create the tables and indexes if necessary
+		boolean compact;
 		Connection txn = startTransaction();
 		try {
 			if (reopen) {
-				checkSchemaVersion(txn, listener);
+				Settings s = getSettings(txn, DB_SETTINGS_NAMESPACE);
+				compact = migrateSchema(txn, s, listener) || isCompactionDue(s);
 			} else {
 				createTables(txn);
-				storeSchemaVersion(txn, CODE_SCHEMA_VERSION);
+				initialiseSettings(txn);
+				compact = false;
 			}
 			createIndexes(txn);
 			commitTransaction(txn);
@@ -351,6 +362,25 @@ abstract class JdbcDatabase implements Database<Connection> {
 			abortTransaction(txn);
 			throw e;
 		}
+		// Compact the database if necessary
+		if (compact) {
+			if (listener != null) listener.onDatabaseCompaction();
+			long start = now();
+			compactAndClose();
+			logDuration(LOG, "Compacting database", start);
+			// Allow the next transaction to reopen the DB
+			synchronized (connectionsLock) {
+				closed = false;
+			}
+			txn = startTransaction();
+			try {
+				storeLastCompacted(txn);
+				commitTransaction(txn);
+			} catch (DbException e) {
+				abortTransaction(txn);
+				throw e;
+			}
+		}
 	}

 	/**
@@ -358,17 +388,18 @@ abstract class JdbcDatabase implements Database<Connection> {
 	 * version used by the current code and applies any suitable migrations to
 	 * the data if necessary.
 	 *
+	 * @return true if any migrations were applied, false if the schema was
+	 * already current
 	 * @throws DataTooNewException if the data uses a newer schema than the
 	 * current code
 	 * @throws DataTooOldException if the data uses an older schema than the
 	 * current code and cannot be migrated
 	 */
-	private void checkSchemaVersion(Connection txn,
+	private boolean migrateSchema(Connection txn, Settings s,
 			@Nullable MigrationListener listener) throws DbException {
-		Settings s = getSettings(txn, DB_SETTINGS_NAMESPACE);
 		int dataSchemaVersion = s.getInt(SCHEMA_VERSION_KEY, -1);
 		if (dataSchemaVersion == -1) throw new DbException();
-		if (dataSchemaVersion == CODE_SCHEMA_VERSION) return;
+		if (dataSchemaVersion == CODE_SCHEMA_VERSION) return false;
 		if (CODE_SCHEMA_VERSION < dataSchemaVersion)
 			throw new DataTooNewException();
 		// Apply any suitable migrations in order
@@ -377,7 +408,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			if (start == dataSchemaVersion) {
 				if (LOG.isLoggable(INFO))
 					LOG.info("Migrating from schema " + start + " to " + end);
-				if (listener != null) listener.onMigrationRun();
+				if (listener != null) listener.onDatabaseMigration();
 				// Apply the migration
 				m.migrate(txn);
 				// Store the new schema version
@@ -387,11 +418,24 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 		if (dataSchemaVersion != CODE_SCHEMA_VERSION)
 			throw new DataTooOldException();
+		return true;
 	}

 	// Package access for testing
 	List<Migration<Connection>> getMigrations() {
-		return singletonList(new Migration38_39());
+		return Arrays.asList(
+				new Migration38_39(),
+				new Migration39_40(),
+				new Migration40_41(dbTypes)
+		);
+	}
+
+	private boolean isCompactionDue(Settings s) {
+		long lastCompacted = s.getLong(LAST_COMPACTED_KEY, 0);
+		long elapsed = clock.currentTimeMillis() - lastCompacted;
+		if (LOG.isLoggable(INFO))
+			LOG.info(elapsed + " ms since last compaction");
+		return elapsed > MAX_COMPACTION_INTERVAL_MS;
 	}

 	private void storeSchemaVersion(Connection txn, int version)
@@ -401,6 +445,19 @@ abstract class JdbcDatabase implements Database<Connection> {
 		mergeSettings(txn, s, DB_SETTINGS_NAMESPACE);
 	}

+	private void storeLastCompacted(Connection txn) throws DbException {
+		Settings s = new Settings();
+		s.putLong(LAST_COMPACTED_KEY, clock.currentTimeMillis());
+		mergeSettings(txn, s, DB_SETTINGS_NAMESPACE);
+	}
+
+	private void initialiseSettings(Connection txn) throws DbException {
+		Settings s = new Settings();
+		s.putInt(SCHEMA_VERSION_KEY, CODE_SCHEMA_VERSION);
+		s.putLong(LAST_COMPACTED_KEY, clock.currentTimeMillis());
+		mergeSettings(txn, s, DB_SETTINGS_NAMESPACE);
+	}
+
 	private void tryToClose(@Nullable ResultSet rs) {
 		try {
 			if (rs != null) rs.close();
@@ -409,7 +466,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}

-	private void tryToClose(@Nullable Statement s) {
+	protected void tryToClose(@Nullable Statement s) {
 		try {
 			if (s != null) s.close();
 		} catch (SQLException e) {
@@ -417,24 +474,32 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}

+	protected void tryToClose(@Nullable Connection c) {
+		try {
+			if (c != null) c.close();
+		} catch (SQLException e) {
+			logException(LOG, WARNING, e);
+		}
+	}
+
 	private void createTables(Connection txn) throws DbException {
 		Statement s = null;
 		try {
 			s = txn.createStatement();
-			s.executeUpdate(insertTypeNames(CREATE_SETTINGS));
-			s.executeUpdate(insertTypeNames(CREATE_LOCAL_AUTHORS));
-			s.executeUpdate(insertTypeNames(CREATE_CONTACTS));
-			s.executeUpdate(insertTypeNames(CREATE_GROUPS));
-			s.executeUpdate(insertTypeNames(CREATE_GROUP_METADATA));
-			s.executeUpdate(insertTypeNames(CREATE_GROUP_VISIBILITIES));
-			s.executeUpdate(insertTypeNames(CREATE_MESSAGES));
-			s.executeUpdate(insertTypeNames(CREATE_MESSAGE_METADATA));
-			s.executeUpdate(insertTypeNames(CREATE_MESSAGE_DEPENDENCIES));
-			s.executeUpdate(insertTypeNames(CREATE_OFFERS));
-			s.executeUpdate(insertTypeNames(CREATE_STATUSES));
-			s.executeUpdate(insertTypeNames(CREATE_TRANSPORTS));
-			s.executeUpdate(insertTypeNames(CREATE_OUTGOING_KEYS));
-			s.executeUpdate(insertTypeNames(CREATE_INCOMING_KEYS));
+			s.executeUpdate(dbTypes.replaceTypes(CREATE_SETTINGS));
+			s.executeUpdate(dbTypes.replaceTypes(CREATE_LOCAL_AUTHORS));
+			s.executeUpdate(dbTypes.replaceTypes(CREATE_CONTACTS));
+			s.executeUpdate(dbTypes.replaceTypes(CREATE_GROUPS));
+			s.executeUpdate(dbTypes.replaceTypes(CREATE_GROUP_METADATA));
+			s.executeUpdate(dbTypes.replaceTypes(CREATE_GROUP_VISIBILITIES));
+			s.executeUpdate(dbTypes.replaceTypes(CREATE_MESSAGES));
+			s.executeUpdate(dbTypes.replaceTypes(CREATE_MESSAGE_METADATA));
+			s.executeUpdate(dbTypes.replaceTypes(CREATE_MESSAGE_DEPENDENCIES));
+			s.executeUpdate(dbTypes.replaceTypes(CREATE_OFFERS));
+			s.executeUpdate(dbTypes.replaceTypes(CREATE_STATUSES));
+			s.executeUpdate(dbTypes.replaceTypes(CREATE_TRANSPORTS));
+			s.executeUpdate(dbTypes.replaceTypes(CREATE_OUTGOING_KEYS));
+			s.executeUpdate(dbTypes.replaceTypes(CREATE_INCOMING_KEYS));
 			s.close();
 		} catch (SQLException e) {
 			tryToClose(s);
@@ -459,15 +524,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}

-	private String insertTypeNames(String s) {
-		s = s.replaceAll("_HASH", hashType);
-		s = s.replaceAll("_SECRET", secretType);
-		s = s.replaceAll("_BINARY", binaryType);
-		s = s.replaceAll("_COUNTER", counterType);
-		s = s.replaceAll("_STRING", stringType);
-		return s;
-	}
-
 	@Override
 	public Connection startTransaction() throws DbException {
 		Connection txn;
@@ -482,7 +538,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 			if (txn == null) {
 				// Open a new connection
 				txn = createConnection();
-				if (txn == null) throw new DbException();
 				txn.setAutoCommit(false);
 				connectionsLock.lock();
 				try {
@@ -669,7 +724,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			while (rs.next()) {
 				MessageId id = new MessageId(rs.getBytes(1));
 				long timestamp = rs.getLong(2);
-				State state = State.fromValue(rs.getInt(3));
+				MessageState state = MessageState.fromValue(rs.getInt(3));
 				boolean messageShared = rs.getBoolean(4);
 				int length = rs.getInt(5);
 				boolean deleted = rs.getBoolean(6);
@@ -712,7 +767,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}

 	@Override
-	public void addMessage(Connection txn, Message m, State state,
+	public void addMessage(Connection txn, Message m, MessageState state,
 			boolean messageShared, @Nullable ContactId sender)
 			throws DbException {
 		PreparedStatement ps = null;
@@ -726,7 +781,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setLong(3, m.getTimestamp());
 			ps.setInt(4, state.getValue());
 			ps.setBoolean(5, messageShared);
-			byte[] raw = m.getRaw();
+			byte[] raw = messageFactory.getRawMessage(m);
 			ps.setInt(6, raw.length);
 			ps.setBytes(7, raw);
 			int affected = ps.executeUpdate();
@@ -740,7 +795,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 				boolean offered = removeOfferedMessage(txn, c, m.getId());
 				boolean seen = offered || (sender != null && c.equals(sender));
 				addStatus(txn, m.getId(), c, m.getGroupId(), m.getTimestamp(),
-						m.getLength(), state, e.getValue(), messageShared,
+						raw.length, state, e.getValue(), messageShared,
 						false, seen);
 			}
 			// Update denormalised column in messageDependencies if dependency
@@ -792,15 +847,16 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}

 	private void addStatus(Connection txn, MessageId m, ContactId c, GroupId g,
-			long timestamp, int length, State state, boolean groupShared,
+			long timestamp, int length, MessageState state, boolean groupShared,
 			boolean messageShared, boolean deleted, boolean seen)
 			throws DbException {
 		PreparedStatement ps = null;
 		try {
 			String sql = "INSERT INTO statuses (messageId, contactId, groupId,"
 					+ " timestamp, length, state, groupShared, messageShared,"
-					+ " deleted, ack, seen, requested, expiry, txCount)"
-					+ " VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, FALSE, 0, 0)";
+					+ " deleted, ack, seen, requested, expiry, txCount, eta)"
+					+ " VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, FALSE, 0, 0,"
+					+ " 0)";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			ps.setInt(2, c.getInt());
@@ -824,7 +880,8 @@ abstract class JdbcDatabase implements Database<Connection> {

 	@Override
 	public void addMessageDependency(Connection txn, Message dependent,
-			MessageId dependency, State dependentState) throws DbException {
+			MessageId dependency, MessageState dependentState)
+			throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
@@ -835,9 +892,9 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setBytes(1, dependency.getBytes());
 			ps.setBytes(2, dependent.getGroupId().getBytes());
 			rs = ps.executeQuery();
-			State dependencyState = null;
+			MessageState dependencyState = null;
 			if (rs.next()) {
-				dependencyState = State.fromValue(rs.getInt(1));
+				dependencyState = MessageState.fromValue(rs.getInt(1));
 				if (rs.next()) throw new DbStateException();
 			}
 			rs.close();
@@ -1193,8 +1250,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT authorId, formatVersion, name, publicKey,"
-					+ " localAuthorId, verified, active"
+			String sql = "SELECT authorId, formatVersion, name, alias,"
+					+ " publicKey, localAuthorId, verified, active"
 					+ " FROM contacts"
 					+ " WHERE contactId = ?";
 			ps = txn.prepareStatement(sql);
@@ -1204,15 +1261,17 @@ abstract class JdbcDatabase implements Database<Connection> {
 			AuthorId authorId = new AuthorId(rs.getBytes(1));
 			int formatVersion = rs.getInt(2);
 			String name = rs.getString(3);
-			byte[] publicKey = rs.getBytes(4);
-			AuthorId localAuthorId = new AuthorId(rs.getBytes(5));
-			boolean verified = rs.getBoolean(6);
-			boolean active = rs.getBoolean(7);
+			String alias = rs.getString(4);
+			byte[] publicKey = rs.getBytes(5);
+			AuthorId localAuthorId = new AuthorId(rs.getBytes(6));
+			boolean verified = rs.getBoolean(7);
+			boolean active = rs.getBoolean(8);
 			rs.close();
 			ps.close();
 			Author author =
 					new Author(authorId, formatVersion, name, publicKey);
-			return new Contact(c, author, localAuthorId, verified, active);
+			return new Contact(c, author, localAuthorId, alias, verified,
+					active);
 		} catch (SQLException e) {
 			tryToClose(rs);
 			tryToClose(ps);
@@ -1227,7 +1286,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		ResultSet rs = null;
 		try {
 			String sql = "SELECT contactId, authorId, formatVersion, name,"
-					+ " publicKey, localAuthorId, verified, active"
+					+ " alias, publicKey, localAuthorId, verified, active"
 					+ " FROM contacts";
 			ps = txn.prepareStatement(sql);
 			rs = ps.executeQuery();
@@ -1237,14 +1296,15 @@ abstract class JdbcDatabase implements Database<Connection> {
 				AuthorId authorId = new AuthorId(rs.getBytes(2));
 				int formatVersion = rs.getInt(3);
 				String name = rs.getString(4);
-				byte[] publicKey = rs.getBytes(5);
+				String alias = rs.getString(5);
+				byte[] publicKey = rs.getBytes(6);
 				Author author =
 						new Author(authorId, formatVersion, name, publicKey);
-				AuthorId localAuthorId = new AuthorId(rs.getBytes(6));
-				boolean verified = rs.getBoolean(7);
-				boolean active = rs.getBoolean(8);
+				AuthorId localAuthorId = new AuthorId(rs.getBytes(7));
+				boolean verified = rs.getBoolean(8);
+				boolean active = rs.getBoolean(9);
 				contacts.add(new Contact(contactId, author, localAuthorId,
-						verified, active));
+						alias, verified, active));
 			}
 			rs.close();
 			ps.close();
@@ -1285,8 +1345,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT contactId, formatVersion, name, publicKey,"
-					+ " localAuthorId, verified, active"
+			String sql = "SELECT contactId, formatVersion, name, alias,"
+					+ " publicKey, localAuthorId, verified, active"
 					+ " FROM contacts"
 					+ " WHERE authorId = ?";
 			ps = txn.prepareStatement(sql);
@@ -1297,14 +1357,15 @@ abstract class JdbcDatabase implements Database<Connection> {
 				ContactId c = new ContactId(rs.getInt(1));
 				int formatVersion = rs.getInt(2);
 				String name = rs.getString(3);
-				byte[] publicKey = rs.getBytes(4);
-				AuthorId localAuthorId = new AuthorId(rs.getBytes(5));
-				boolean verified = rs.getBoolean(6);
-				boolean active = rs.getBoolean(7);
+				String alias = rs.getString(4);
+				byte[] publicKey = rs.getBytes(5);
+				AuthorId localAuthorId = new AuthorId(rs.getBytes(6));
+				boolean verified = rs.getBoolean(7);
+				boolean active = rs.getBoolean(8);
 				Author author =
 						new Author(remote, formatVersion, name, publicKey);
-				contacts.add(new Contact(c, author, localAuthorId, verified,
-						active));
+				contacts.add(new Contact(c, author, localAuthorId, alias,
+						verified, active));
 			}
 			rs.close();
 			ps.close();
@@ -1482,6 +1543,35 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}

+	@Override
+	public Message getMessage(Connection txn, MessageId m) throws DbException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT groupId, timestamp, raw FROM messages"
+					+ " WHERE messageId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			rs = ps.executeQuery();
+			if (!rs.next()) throw new DbStateException();
+			GroupId g = new GroupId(rs.getBytes(1));
+			long timestamp = rs.getLong(2);
+			byte[] raw = rs.getBytes(3);
+			if (rs.next()) throw new DbStateException();
+			rs.close();
+			ps.close();
+			if (raw == null) throw new MessageDeletedException();
+			if (raw.length <= MESSAGE_HEADER_LENGTH) throw new AssertionError();
+			byte[] body = new byte[raw.length - MESSAGE_HEADER_LENGTH];
+			System.arraycopy(raw, MESSAGE_HEADER_LENGTH, body, 0, body.length);
+			return new Message(m, g, timestamp, body);
+		} catch (SQLException e) {
+			tryToClose(rs);
+			tryToClose(ps);
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	public Collection<MessageId> getMessageIds(Connection txn, GroupId g)
 			throws DbException {
@@ -1724,7 +1814,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}

 	@Override
-	public Map<MessageId, State> getMessageDependencies(Connection txn,
+	public Map<MessageId, MessageState> getMessageDependencies(Connection txn,
 			MessageId m) throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
@@ -1735,10 +1825,10 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			rs = ps.executeQuery();
-			Map<MessageId, State> dependencies = new HashMap<>();
+			Map<MessageId, MessageState> dependencies = new HashMap<>();
 			while (rs.next()) {
 				MessageId dependency = new MessageId(rs.getBytes(1));
-				State state = State.fromValue(rs.getInt(2));
+				MessageState state = MessageState.fromValue(rs.getInt(2));
 				if (rs.wasNull())
 					state = UNKNOWN; // Missing or in a different group
 				dependencies.put(dependency, state);
@@ -1754,7 +1844,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}

 	@Override
-	public Map<MessageId, State> getMessageDependents(Connection txn,
+	public Map<MessageId, MessageState> getMessageDependents(Connection txn,
 			MessageId m) throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
@@ -1768,10 +1858,10 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			rs = ps.executeQuery();
-			Map<MessageId, State> dependents = new HashMap<>();
+			Map<MessageId, MessageState> dependents = new HashMap<>();
 			while (rs.next()) {
 				MessageId dependent = new MessageId(rs.getBytes(1));
-				State state = State.fromValue(rs.getInt(2));
+				MessageState state = MessageState.fromValue(rs.getInt(2));
 				dependents.put(dependent, state);
 			}
 			rs.close();
@@ -1785,7 +1875,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}

 	@Override
-	public State getMessageState(Connection txn, MessageId m)
+	public MessageState getMessageState(Connection txn, MessageId m)
 			throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
@@ -1795,7 +1885,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setBytes(1, m.getBytes());
 			rs = ps.executeQuery();
 			if (!rs.next()) throw new DbStateException();
-			State state = State.fromValue(rs.getInt(1));
+			MessageState state = MessageState.fromValue(rs.getInt(1));
 			if (rs.next()) throw new DbStateException();
 			rs.close();
 			ps.close();
@@ -1834,8 +1924,9 @@ abstract class JdbcDatabase implements Database<Connection> {

 	@Override
 	public Collection<MessageId> getMessagesToOffer(Connection txn,
-			ContactId c, int maxMessages) throws DbException {
+			ContactId c, int maxMessages, int maxLatency) throws DbException {
 		long now = clock.currentTimeMillis();
+		long eta = now + maxLatency;
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
@@ -1844,13 +1935,14 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " AND groupShared = TRUE AND messageShared = TRUE"
 					+ " AND deleted = FALSE"
 					+ " AND seen = FALSE AND requested = FALSE"
-					+ " AND expiry < ?"
+					+ " AND (expiry <= ? OR eta > ?)"
 					+ " ORDER BY timestamp LIMIT ?";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, c.getInt());
 			ps.setInt(2, DELIVERED.getValue());
 			ps.setLong(3, now);
-			ps.setInt(4, maxMessages);
+			ps.setLong(4, eta);
+			ps.setInt(5, maxMessages);
 			rs = ps.executeQuery();
 			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
@@ -1891,8 +1983,9 @@ abstract class JdbcDatabase implements Database<Connection> {

 	@Override
 	public Collection<MessageId> getMessagesToSend(Connection txn, ContactId c,
-			int maxLength) throws DbException {
+			int maxLength, int maxLatency) throws DbException {
 		long now = clock.currentTimeMillis();
+		long eta = now + maxLatency;
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
@@ -1901,12 +1994,13 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " AND groupShared = TRUE AND messageShared = TRUE"
 					+ " AND deleted = FALSE"
 					+ " AND seen = FALSE"
-					+ " AND expiry < ?"
+					+ " AND (expiry <= ? OR eta > ?)"
 					+ " ORDER BY timestamp";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, c.getInt());
 			ps.setInt(2, DELIVERED.getValue());
 			ps.setLong(3, now);
+			ps.setLong(4, eta);
 			rs = ps.executeQuery();
 			List<MessageId> ids = new ArrayList<>();
 			int total = 0;
@@ -1939,7 +2033,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}

 	private Collection<MessageId> getMessagesInState(Connection txn,
-			State state) throws DbException {
+			MessageState state) throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
@@ -2018,34 +2112,11 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}

-	@Override
-	@Nullable
-	public byte[] getRawMessage(Connection txn, MessageId m)
-			throws DbException {
-		PreparedStatement ps = null;
-		ResultSet rs = null;
-		try {
-			String sql = "SELECT raw FROM messages WHERE messageId = ?";
-			ps = txn.prepareStatement(sql);
-			ps.setBytes(1, m.getBytes());
-			rs = ps.executeQuery();
-			if (!rs.next()) throw new DbStateException();
-			byte[] raw = rs.getBytes(1);
-			if (rs.next()) throw new DbStateException();
-			rs.close();
-			ps.close();
-			return raw;
-		} catch (SQLException e) {
-			tryToClose(rs);
-			tryToClose(ps);
-			throw new DbException(e);
-		}
-	}
-
 	@Override
 	public Collection<MessageId> getRequestedMessagesToSend(Connection txn,
-			ContactId c, int maxLength) throws DbException {
+			ContactId c, int maxLength, int maxLatency) throws DbException {
 		long now = clock.currentTimeMillis();
+		long eta = now + maxLatency;
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
@@ -2054,12 +2125,13 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " AND groupShared = TRUE AND messageShared = TRUE"
 					+ " AND deleted = FALSE"
 					+ " AND seen = FALSE AND requested = TRUE"
-					+ " AND expiry < ?"
+					+ " AND (expiry <= ? OR eta > ?)"
 					+ " ORDER BY timestamp";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, c.getInt());
 			ps.setInt(2, DELIVERED.getValue());
 			ps.setLong(3, now);
+			ps.setLong(4, eta);
 			rs = ps.executeQuery();
 			List<MessageId> ids = new ArrayList<>();
 			int total = 0;
@@ -2288,7 +2360,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			rs = ps.executeQuery();
 			if (!rs.next()) throw new DbStateException();
 			GroupId g = new GroupId(rs.getBytes(1));
-			State state = State.fromValue(rs.getInt(2));
+			MessageState state = MessageState.fromValue(rs.getInt(2));
 			rs.close();
 			ps.close();
 			// Insert any keys that don't already exist
@@ -2718,6 +2790,25 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}

+	@Override
+	public void setContactAlias(Connection txn, ContactId c,
+			@Nullable String alias) throws DbException {
+		PreparedStatement ps = null;
+		try {
+			String sql = "UPDATE contacts SET alias = ? WHERE contactId = ?";
+			ps = txn.prepareStatement(sql);
+			if (alias == null) ps.setNull(1, VARCHAR);
+			else ps.setString(1, alias);
+			ps.setInt(2, c.getInt());
+			int affected = ps.executeUpdate();
+			if (affected < 0 || affected > 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			tryToClose(ps);
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	public void setGroupVisibility(Connection txn, ContactId c, GroupId g,
 			boolean shared) throws DbException {
@@ -2775,7 +2866,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}

 	@Override
-	public void setMessageState(Connection txn, MessageId m, State state)
+	public void setMessageState(Connection txn, MessageId m, MessageState state)
 			throws DbException {
 		PreparedStatement ps = null;
 		try {
@@ -2870,7 +2961,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}

 	@Override
-	public void updateExpiryTime(Connection txn, ContactId c, MessageId m,
+	public void updateExpiryTimeAndEta(Connection txn, ContactId c, MessageId m,
 			int maxLatency) throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
@@ -2886,13 +2977,16 @@ abstract class JdbcDatabase implements Database<Connection> {
 			if (rs.next()) throw new DbStateException();
 			rs.close();
 			ps.close();
-			sql = "UPDATE statuses SET expiry = ?, txCount = txCount + 1"
+			sql = "UPDATE statuses"
+					+ " SET expiry = ?, txCount = txCount + 1, eta = ?"
 					+ " WHERE messageId = ? AND contactId = ?";
 			ps = txn.prepareStatement(sql);
 			long now = clock.currentTimeMillis();
+			long eta = now + maxLatency;
 			ps.setLong(1, calculateExpiry(now, maxLatency, txCount));
-			ps.setBytes(2, m.getBytes());
-			ps.setInt(3, c.getInt());
+			ps.setLong(2, eta);
+			ps.setBytes(3, m.getBytes());
+			ps.setInt(4, c.getInt());
 			int affected = ps.executeUpdate();
 			if (affected != 1) throw new DbStateException();
 			ps.close();
@@ -0,0 +1,54 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.db.DbException;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+
+import static java.util.logging.Level.WARNING;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+class Migration39_40 implements Migration<Connection> {
+
+	private static final Logger LOG =
+			Logger.getLogger(Migration39_40.class.getName());
+
+	@Override
+	public int getStartVersion() {
+		return 39;
+	}
+
+	@Override
+	public int getEndVersion() {
+		return 40;
+	}
+
+	@Override
+	public void migrate(Connection txn) throws DbException {
+		Statement s = null;
+		try {
+			s = txn.createStatement();
+			s.execute("ALTER TABLE statuses"
+					+ " ADD eta BIGINT");
+			s.execute("UPDATE statuses SET eta = 0");
+			s.execute("ALTER TABLE statuses"
+					+ " ALTER COLUMN eta"
+					+ " SET NOT NULL");
+		} catch (SQLException e) {
+			tryToClose(s);
+			throw new DbException(e);
+		}
+	}
+
+	private void tryToClose(@Nullable Statement s) {
+		try {
+			if (s != null) s.close();
+		} catch (SQLException e) {
+			logException(LOG, WARNING, e);
+		}
+	}
+}
@@ -0,0 +1,56 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.db.DbException;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+class Migration40_41 implements Migration<Connection> {
+
+	private static final Logger LOG = getLogger(Migration40_41.class.getName());
+
+	private final DatabaseTypes dbTypes;
+
+	public Migration40_41(DatabaseTypes databaseTypes) {
+		this.dbTypes = databaseTypes;
+	}
+
+	@Override
+	public int getStartVersion() {
+		return 40;
+	}
+
+	@Override
+	public int getEndVersion() {
+		return 41;
+	}
+
+	@Override
+	public void migrate(Connection txn) throws DbException {
+		Statement s = null;
+		try {
+			s = txn.createStatement();
+			s.execute("ALTER TABLE contacts"
+					+ dbTypes.replaceTypes(" ADD alias _STRING"));
+		} catch (SQLException e) {
+			tryToClose(s);
+			throw new DbException(e);
+		}
+	}
+
+	private void tryToClose(@Nullable Statement s) {
+		try {
+			if (s != null) s.close();
+		} catch (SQLException e) {
+			logException(LOG, WARNING, e);
+		}
+	}
+}
@@ -1,29 +1,21 @@
 package org.briarproject.bramble.identity;

-import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.KeyPair;
 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.Author.Status;
 import org.briarproject.bramble.api.identity.AuthorFactory;
-import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;

-import java.util.Collection;
 import java.util.logging.Logger;

 import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 import javax.inject.Inject;

-import static org.briarproject.bramble.api.identity.Author.Status.OURSELVES;
-import static org.briarproject.bramble.api.identity.Author.Status.UNKNOWN;
-import static org.briarproject.bramble.api.identity.Author.Status.UNVERIFIED;
-import static org.briarproject.bramble.api.identity.Author.Status.VERIFIED;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.now;

@@ -75,27 +67,16 @@ class IdentityManagerImpl implements IdentityManager {
 			LOG.info("No local author to store");
 			return;
 		}
-		Transaction txn = db.startTransaction(false);
-		try {
-			db.addLocalAuthor(txn, cached);
-			db.commitTransaction(txn);
+		db.transaction(false, txn -> db.addLocalAuthor(txn, cached));
 		LOG.info("Local author stored");
-		} finally {
-			db.endTransaction(txn);
-		}
 	}

 	@Override
 	public LocalAuthor getLocalAuthor() throws DbException {
 		if (cachedAuthor == null) {
-			Transaction txn = db.startTransaction(true);
-			try {
-				cachedAuthor = loadLocalAuthor(txn);
+			cachedAuthor =
+					db.transactionWithResult(true, this::loadLocalAuthor);
 			LOG.info("Local author loaded");
-				db.commitTransaction(txn);
-			} finally {
-				db.endTransaction(txn);
-			}
 		}
 		LocalAuthor cached = cachedAuthor;
 		if (cached == null) throw new AssertionError();
@@ -118,26 +99,4 @@ class IdentityManagerImpl implements IdentityManager {
 		return db.getLocalAuthors(txn).iterator().next();
 	}

-	@Override
-	public Status getAuthorStatus(AuthorId authorId) throws DbException {
-		Transaction txn = db.startTransaction(true);
-		try {
-			return getAuthorStatus(txn, authorId);
-		} finally {
-			db.endTransaction(txn);
-		}
-	}
-
-	@Override
-	public Status getAuthorStatus(Transaction txn, AuthorId authorId)
-			throws DbException {
-		if (getLocalAuthor(txn).getId().equals(authorId)) return OURSELVES;
-		Collection<Contact> contacts = db.getContactsByAuthorId(txn, authorId);
-		if (contacts.isEmpty()) return UNKNOWN;
-		for (Contact c : contacts) {
-			if (c.isVerified()) return VERIFIED;
-		}
-		return UNVERIFIED;
-	}
-
 }
@@ -102,6 +102,7 @@ class KeyAgreementTaskImpl extends Thread implements KeyAgreementTask,
 		KeyAgreementTransport transport =
 				connector.connect(remotePayload, alice);
 		if (transport == null) {
+			LOG.warning("Key agreement failed. Transport was null.");
 			// Notify caller that the connection failed
 			eventBus.broadcast(new KeyAgreementFailedEvent());
 			return;
@@ -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;
@@ -21,6 +21,7 @@ import java.util.List;
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;

+import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.BETA_PROTOCOL_VERSION;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.COMMIT_LENGTH;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.PROTOCOL_VERSION;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.TRANSPORT_ID_BLUETOOTH;
@@ -43,8 +44,11 @@ class PayloadParserImpl implements PayloadParser {
 		// First byte: the protocol version
 		int protocolVersion = in.read();
 		if (protocolVersion == -1) throw new FormatException();
-		if (protocolVersion != PROTOCOL_VERSION)
-			throw new UnsupportedVersionException();
+		if (protocolVersion != PROTOCOL_VERSION) {
+			boolean tooOld = protocolVersion < PROTOCOL_VERSION ||
+					protocolVersion == BETA_PROTOCOL_VERSION;
+			throw new UnsupportedVersionException(tooOld);
+		}
 		// The rest of the payload is a BDF list with one or more elements
 		BdfReader r = bdfReaderFactory.createReader(in);
 		BdfList payload = r.readList();
@@ -6,7 +6,6 @@ import org.briarproject.bramble.api.db.DataTooOldException;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.MigrationListener;
-import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
@@ -29,6 +28,7 @@ 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 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;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.STARTING;
@@ -114,20 +114,16 @@ class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
 			dbLatch.countDown();
 			eventBus.broadcast(new LifecycleEvent(STARTING_SERVICES));

-			Transaction txn = db.startTransaction(false);
-			try {
+			db.transaction(false, txn -> {
 				for (Client c : clients) {
-					start = now();
+					long start1 = now();
 					c.createLocalState(txn);
 					if (LOG.isLoggable(FINE)) {
 						logDuration(LOG, "Starting client "
-								+ c.getClass().getSimpleName(), start);
+								+ c.getClass().getSimpleName(), start1);
 					}
 				}
-				db.commitTransaction(txn);
-			} finally {
-				db.endTransaction(txn);
-			}
+			});
 			for (Service s : services) {
 				start = now();
 				s.startService();
@@ -159,11 +155,17 @@ class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
 	}

 	@Override
-	public void onMigrationRun() {
+	public void onDatabaseMigration() {
 		state = MIGRATING_DATABASE;
 		eventBus.broadcast(new LifecycleEvent(MIGRATING_DATABASE));
 	}

+	@Override
+	public void onDatabaseCompaction() {
+		state = COMPACTING_DATABASE;
+		eventBus.broadcast(new LifecycleEvent(COMPACTING_DATABASE));
+	}
+
 	@Override
 	public void stopServices() {
 		try {
--- a/Show More
+++ b/Show More