DO NOT MERGE: Log contact name and alias.

Use the logger. Log the contact name, alias and message status.

.gitignore

@@ -9,15 +9,21 @@ Thumbs.db
 .DS_Store
 
 # Eclipse project files
-#.classpath
-#.project
+.classpath
+.project
+.settings
 
 # Local configuration file (sdk path, etc)
 local.properties
 
 # Android Studio
 .idea/*
+!.idea/inspectionProfiles/
+!.idea/runConfigurations/
 !.idea/codeStyleSettings.xml
+!.idea/codeStyles
 .gradle
 build/
+captures
 *.iml
+projectFilesBackup/

.gitlab-ci.yml

@@ -0,0 +1,106 @@
+image: briar/ci-image-android:latest
+
+stages:
+  - test
+  - optional_tests
+  - check_reproducibility
+
+variables:
+  GIT_SUBMODULE_STRATEGY: recursive
+
+workflow:
+  # when to create a CI pipeline
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
+    - if: '$CI_COMMIT_BRANCH && $CI_OPEN_MERGE_REQUESTS'
+      when: never # avoids duplicate jobs for branch and MR
+    - if: '$CI_COMMIT_BRANCH'
+    - if: '$CI_COMMIT_TAG'
+
+.base-test:
+  before_script:
+    - set -e
+    - export GRADLE_USER_HOME=$PWD/.gradle
+  cache:
+    key: "$CI_COMMIT_REF_SLUG"
+    paths:
+      - .gradle/wrapper
+      - .gradle/caches
+  after_script:
+    # these file change every time and should not be cached
+    - rm -f $GRADLE_USER_HOME/caches/modules-2/modules-2.lock
+    - rm -fr $GRADLE_USER_HOME/caches/*/plugin-resolution/
+
+test:
+  extends: .base-test
+  stage: test
+  script:
+    - git submodule update
+    - ./gradlew -Djava.security.egd=file:/dev/urandom animalSnifferMain animalSnifferTest
+    - ./gradlew -Djava.security.egd=file:/dev/urandom assembleOfficialDebug :briar-headless:linuxJars
+    - ./gradlew -Djava.security.egd=file:/dev/urandom compileOfficialDebugAndroidTestSources compileScreenshotDebugAndroidTestSources check
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
+      when: always
+    - when: always
+
+android test:
+  extends: .base-test
+  stage: optional_tests
+  image: briar/ci-image-android-emulator:latest
+  script:
+    # start emulator first, so it can fail early
+    - start-emulator.sh
+    # run normal and screenshot tests together (exclude Large tests)
+    - ./gradlew -Djava.security.egd=file:/dev/urandom connectedAndroidTest -Pandroid.testInstrumentationRunnerArguments.package=org.briarproject.briar.android -Pandroid.testInstrumentationRunnerArguments.notAnnotation=androidx.test.filters.LargeTest
+  after_script:
+    - adb pull /sdcard/Pictures/screenshots
+  artifacts:
+    name: "${CI_PROJECT_PATH}_${CI_JOB_STAGE}_${CI_COMMIT_REF_NAME}_${CI_COMMIT_SHA}"
+    paths:
+      - kernel.log
+      - logcat.txt
+      - briar-android/build/reports/androidTests/connected/flavors/*
+      - screenshots
+    expire_in: 3 days
+    when: on_failure
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "schedule"'
+      when: manual
+    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
+      changes:
+        - briar-android/**/*
+      when: manual
+      allow_failure: true
+    - if: '$CI_COMMIT_TAG == null'
+      when: manual
+      allow_failure: true
+  retry:
+    max: 1
+  tags:
+    - kvm
+
+test_reproducible:
+  stage: check_reproducibility
+  script:
+    - "curl -X POST -F token=${RELEASE_CHECK_TOKEN} -F ref=master -F variables[APP]='briar' -F variables[RELEASE_TAG]=${CI_COMMIT_REF_NAME} https://code.briarproject.org/api/v4/projects/61/trigger/pipeline"
+    - "curl -X POST -F token=${RELEASE_JAR_CHECK_TOKEN} -F ref=main -F variables[APP]='briar-headless' -F variables[RELEASE_TAG]=${CI_COMMIT_REF_NAME} https://code.briarproject.org/api/v4/projects/307/trigger/pipeline"
+  only:
+    - tags
+
+mailbox integration test:
+  stage: optional_tests
+  extends: .base-test
+  rules:
+    - changes:
+        - mailbox-integration-tests/**/*
+      when: on_success
+      allow_failure: false
+    - if: '$CI_PIPELINE_SOURCE == "schedule"'
+      when: on_success
+    - if: '$CI_COMMIT_TAG == null'
+      when: manual
+      allow_failure: true # TODO figure out how not to allow failure while leaving this optional
+  script:
+    - (cd briar-mailbox; git fetch; git reset --hard origin/main)
+    - MAILBOX_INTEGRATION_TESTS=true ./gradlew --info mailbox-integration-tests:test

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "briar-mailbox"]
+	path = briar-mailbox
+	url = https://code.briarproject.org/briar/briar-mailbox.git

.idea/codeStyleSettings.xml

@@ -31,6 +31,8 @@
           </value>
         </option>
         <option name="RIGHT_MARGIN" value="100" />
+        <option name="JD_ALIGN_PARAM_COMMENTS" value="false" />
+        <option name="JD_ALIGN_EXCEPTION_COMMENTS" value="false" />
         <AndroidXmlCodeStyleSettings>
           <option name="USE_CUSTOM_SETTINGS" value="true" />
         </AndroidXmlCodeStyleSettings>
@@ -68,6 +70,12 @@
         <XML>
           <option name="XML_LEGACY_SETTINGS_IMPORTED" value="true" />
         </XML>
+        <codeStyleSettings language="Groovy">
+          <indentOptions>
+            <option name="USE_TAB_CHARACTER" value="true" />
+            <option name="SMART_TABS" value="true" />
+          </indentOptions>
+        </codeStyleSettings>
         <codeStyleSettings language="JAVA">
           <option name="RIGHT_MARGIN" value="80" />
           <option name="ALIGN_MULTILINE_PARAMETERS" value="false" />

.idea/codeStyles/Project.xml

@@ -0,0 +1,193 @@
+<component name="ProjectCodeStyleConfiguration">
+  <code_scheme name="Project" version="173">
+    <JavaCodeStyleSettings>
+      <option name="ANNOTATION_PARAMETER_WRAP" value="1" />
+      <option name="IMPORT_LAYOUT_TABLE">
+        <value>
+          <package name="android" withSubpackages="true" static="false" />
+          <emptyLine />
+          <package name="com" withSubpackages="true" static="false" />
+          <emptyLine />
+          <package name="junit" withSubpackages="true" static="false" />
+          <emptyLine />
+          <package name="net" withSubpackages="true" static="false" />
+          <emptyLine />
+          <package name="org" withSubpackages="true" static="false" />
+          <emptyLine />
+          <package name="java" withSubpackages="true" static="false" />
+          <emptyLine />
+          <package name="javax" withSubpackages="true" static="false" />
+          <emptyLine />
+          <package name="" withSubpackages="true" static="false" />
+          <emptyLine />
+          <package name="" withSubpackages="true" static="true" />
+          <emptyLine />
+        </value>
+      </option>
+      <option name="JD_ALIGN_PARAM_COMMENTS" value="false" />
+      <option name="JD_ALIGN_EXCEPTION_COMMENTS" value="false" />
+    </JavaCodeStyleSettings>
+    <JetCodeStyleSettings>
+      <option name="PACKAGES_TO_USE_STAR_IMPORTS">
+        <value />
+      </option>
+      <option name="NAME_COUNT_TO_USE_STAR_IMPORT" value="2147483647" />
+      <option name="NAME_COUNT_TO_USE_STAR_IMPORT_FOR_MEMBERS" value="2147483647" />
+      <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
+    </JetCodeStyleSettings>
+    <codeStyleSettings language="Groovy">
+      <indentOptions>
+        <option name="USE_TAB_CHARACTER" value="true" />
+        <option name="SMART_TABS" value="true" />
+      </indentOptions>
+    </codeStyleSettings>
+    <codeStyleSettings language="JAVA">
+      <option name="RIGHT_MARGIN" value="80" />
+      <option name="ALIGN_MULTILINE_PARAMETERS" value="false" />
+      <option name="ALIGN_MULTILINE_RESOURCES" value="false" />
+      <option name="ALIGN_MULTILINE_FOR" value="false" />
+      <option name="SPACE_BEFORE_ARRAY_INITIALIZER_LBRACE" value="true" />
+      <option name="CALL_PARAMETERS_WRAP" value="1" />
+      <option name="METHOD_PARAMETERS_WRAP" value="1" />
+      <option name="RESOURCE_LIST_WRAP" value="1" />
+      <option name="EXTENDS_LIST_WRAP" value="1" />
+      <option name="THROWS_LIST_WRAP" value="1" />
+      <option name="EXTENDS_KEYWORD_WRAP" value="1" />
+      <option name="THROWS_KEYWORD_WRAP" value="1" />
+      <option name="METHOD_CALL_CHAIN_WRAP" value="1" />
+      <option name="BINARY_OPERATION_WRAP" value="1" />
+      <option name="TERNARY_OPERATION_WRAP" value="1" />
+      <option name="FOR_STATEMENT_WRAP" value="1" />
+      <option name="ARRAY_INITIALIZER_WRAP" value="1" />
+      <option name="ASSIGNMENT_WRAP" value="1" />
+      <option name="ASSERT_STATEMENT_WRAP" value="1" />
+      <option name="PARAMETER_ANNOTATION_WRAP" value="1" />
+      <option name="VARIABLE_ANNOTATION_WRAP" value="1" />
+      <option name="ENUM_CONSTANTS_WRAP" value="1" />
+      <indentOptions>
+        <option name="USE_TAB_CHARACTER" value="true" />
+        <option name="SMART_TABS" value="true" />
+      </indentOptions>
+    </codeStyleSettings>
+    <codeStyleSettings language="XML">
+      <indentOptions>
+        <option name="CONTINUATION_INDENT_SIZE" value="4" />
+        <option name="USE_TAB_CHARACTER" value="true" />
+        <option name="SMART_TABS" value="true" />
+      </indentOptions>
+      <arrangement>
+        <rules>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>xmlns:android</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>^$</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>xmlns:.*</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>^$</XML_NAMESPACE>
+                </AND>
+              </match>
+              <order>BY_NAME</order>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*:id</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*:name</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>name</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>^$</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>style</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>^$</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>^$</XML_NAMESPACE>
+                </AND>
+              </match>
+              <order>BY_NAME</order>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
+                </AND>
+              </match>
+              <order>ANDROID_ATTRIBUTE_ORDER</order>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>.*</XML_NAMESPACE>
+                </AND>
+              </match>
+              <order>BY_NAME</order>
+            </rule>
+          </section>
+        </rules>
+      </arrangement>
+    </codeStyleSettings>
+    <codeStyleSettings language="kotlin">
+      <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
+      <indentOptions>
+        <option name="CONTINUATION_INDENT_SIZE" value="4" />
+      </indentOptions>
+    </codeStyleSettings>
+  </code_scheme>
+</component>

.idea/codeStyles/codeStyleConfig.xml

@@ -0,0 +1,5 @@
+<component name="ProjectCodeStyleConfiguration">
+  <state>
+    <option name="USE_PER_PROJECT_SETTINGS" value="true" />
+  </state>
+</component>

.idea/dictionaries/briar.xml

@@ -0,0 +1,15 @@
+<component name="ProjectDictionaryState">
+  <dictionary name="briar">
+    <words>
+      <w>briar</w>
+      <w>briarproject</w>
+      <w>emoji</w>
+      <w>encrypter</w>
+      <w>identicon</w>
+      <w>introducee</w>
+      <w>introducees</w>
+      <w>introducer</w>
+      <w>onboarding</w>
+    </words>
+  </dictionary>
+</component>

.idea/inspectionProfiles/Project_Default.xml

@@ -0,0 +1,14 @@
+<component name="InspectionProjectProfileManager">
+  <profile version="1.0">
+    <option name="myName" value="Project Default" />
+    <inspection_tool class="MissingOverrideAnnotation" enabled="true" level="WARNING" enabled_by_default="true">
+      <option name="ignoreObjectMethods" value="true" />
+      <option name="ignoreAnonymousClassMethods" value="false" />
+    </inspection_tool>
+    <inspection_tool class="WeakerAccess" enabled="true" level="WARNING" enabled_by_default="true">
+      <option name="SUGGEST_PACKAGE_LOCAL_FOR_MEMBERS" value="true" />
+      <option name="SUGGEST_PACKAGE_LOCAL_FOR_TOP_CLASSES" value="true" />
+      <option name="SUGGEST_PRIVATE_FOR_INNERS" value="true" />
+    </inspection_tool>
+  </profile>
+</component>

.idea/runConfigurations/All_tests.xml

@@ -0,0 +1,32 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests" type="GradleRunConfiguration" factoryName="Gradle">
+    <ExternalSystemSettings>
+      <option name="executionName" />
+      <option name="externalProjectPath" value="$PROJECT_DIR$" />
+      <option name="externalSystemIdString" value="GRADLE" />
+      <option name="scriptParameters" value="" />
+      <option name="taskDescriptions">
+        <list />
+      </option>
+      <option name="taskNames">
+        <list>
+          <option value=":briar-android:testOfficialDebugUnitTest" />
+          <option value=":briar-android:testScreenshotDebugUnitTest" />
+        </list>
+      </option>
+      <option name="vmOptions" value="" />
+    </ExternalSystemSettings>
+    <ExternalSystemDebugServerProcess>false</ExternalSystemDebugServerProcess>
+    <ExternalSystemReattachDebugProcess>true</ExternalSystemReattachDebugProcess>
+    <DebugAllEnabled>false</DebugAllEnabled>
+    <method v="2">
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in bramble-api" run_configuration_type="GradleRunConfiguration" />
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in bramble-core" run_configuration_type="GradleRunConfiguration" />
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in bramble-java" run_configuration_type="GradleRunConfiguration" />
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in bramble-android" run_configuration_type="GradleRunConfiguration" />
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in briar-api" run_configuration_type="GradleRunConfiguration" />
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in briar-core" run_configuration_type="GradleRunConfiguration" />
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="All tests in briar-headless" run_configuration_type="GradleRunConfiguration" />
+    </method>
+  </configuration>
+</component>

.idea/runConfigurations/All_tests_in_bramble_android.xml

@@ -0,0 +1,23 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests in bramble-android" type="GradleRunConfiguration" factoryName="Gradle">
+    <ExternalSystemSettings>
+      <option name="executionName" />
+      <option name="externalProjectPath" value="$PROJECT_DIR$" />
+      <option name="externalSystemIdString" value="GRADLE" />
+      <option name="scriptParameters" value="" />
+      <option name="taskDescriptions">
+        <list />
+      </option>
+      <option name="taskNames">
+        <list>
+          <option value=":bramble-android:testDebugUnitTest" />
+        </list>
+      </option>
+      <option name="vmOptions" value="" />
+    </ExternalSystemSettings>
+    <ExternalSystemDebugServerProcess>false</ExternalSystemDebugServerProcess>
+    <ExternalSystemReattachDebugProcess>true</ExternalSystemReattachDebugProcess>
+    <DebugAllEnabled>false</DebugAllEnabled>
+    <method v="2" />
+  </configuration>
+</component>

.idea/runConfigurations/All_tests_in_bramble_api.xml

@@ -0,0 +1,25 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests in bramble-api" type="GradleRunConfiguration" factoryName="Gradle">
+    <ExternalSystemSettings>
+      <option name="executionName" />
+      <option name="externalProjectPath" value="$PROJECT_DIR$" />
+      <option name="externalSystemIdString" value="GRADLE" />
+      <option name="scriptParameters" value="" />
+      <option name="taskDescriptions">
+        <list />
+      </option>
+      <option name="taskNames">
+        <list>
+          <option value=":bramble-api:animalSnifferMain" />
+          <option value=":bramble-api:animalSnifferTest" />
+          <option value=":bramble-api:test" />
+        </list>
+      </option>
+      <option name="vmOptions" value="" />
+    </ExternalSystemSettings>
+    <ExternalSystemDebugServerProcess>false</ExternalSystemDebugServerProcess>
+    <ExternalSystemReattachDebugProcess>true</ExternalSystemReattachDebugProcess>
+    <DebugAllEnabled>false</DebugAllEnabled>
+    <method v="2" />
+  </configuration>
+</component>

.idea/runConfigurations/All_tests_in_bramble_core.xml

@@ -0,0 +1,25 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests in bramble-core" type="GradleRunConfiguration" factoryName="Gradle">
+    <ExternalSystemSettings>
+      <option name="executionName" />
+      <option name="externalProjectPath" value="$PROJECT_DIR$" />
+      <option name="externalSystemIdString" value="GRADLE" />
+      <option name="scriptParameters" value="" />
+      <option name="taskDescriptions">
+        <list />
+      </option>
+      <option name="taskNames">
+        <list>
+          <option value=":bramble-core:animalSnifferMain" />
+          <option value=":bramble-core:animalSnifferTest" />
+          <option value=":bramble-core:test" />
+        </list>
+      </option>
+      <option name="vmOptions" value="" />
+    </ExternalSystemSettings>
+    <ExternalSystemDebugServerProcess>false</ExternalSystemDebugServerProcess>
+    <ExternalSystemReattachDebugProcess>true</ExternalSystemReattachDebugProcess>
+    <DebugAllEnabled>false</DebugAllEnabled>
+    <method v="2" />
+  </configuration>
+</component>

.idea/runConfigurations/All_tests_in_bramble_java.xml

@@ -0,0 +1,23 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests in bramble-java" type="GradleRunConfiguration" factoryName="Gradle">
+    <ExternalSystemSettings>
+      <option name="executionName" />
+      <option name="externalProjectPath" value="$PROJECT_DIR$" />
+      <option name="externalSystemIdString" value="GRADLE" />
+      <option name="scriptParameters" value="" />
+      <option name="taskDescriptions">
+        <list />
+      </option>
+      <option name="taskNames">
+        <list>
+          <option value=":bramble-java:test" />
+        </list>
+      </option>
+      <option name="vmOptions" value="" />
+    </ExternalSystemSettings>
+    <ExternalSystemDebugServerProcess>false</ExternalSystemDebugServerProcess>
+    <ExternalSystemReattachDebugProcess>true</ExternalSystemReattachDebugProcess>
+    <DebugAllEnabled>false</DebugAllEnabled>
+    <method v="2" />
+  </configuration>
+</component>

.idea/runConfigurations/All_tests_in_briar_android.xml

@@ -0,0 +1,24 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests in briar-android" type="GradleRunConfiguration" factoryName="Gradle">
+    <ExternalSystemSettings>
+      <option name="executionName" />
+      <option name="externalProjectPath" value="$PROJECT_DIR$" />
+      <option name="externalSystemIdString" value="GRADLE" />
+      <option name="scriptParameters" value="" />
+      <option name="taskDescriptions">
+        <list />
+      </option>
+      <option name="taskNames">
+        <list>
+          <option value=":briar-android:testOfficialDebugUnitTest" />
+          <option value=":briar-android:testScreenshotDebugUnitTest" />
+        </list>
+      </option>
+      <option name="vmOptions" value="" />
+    </ExternalSystemSettings>
+    <ExternalSystemDebugServerProcess>false</ExternalSystemDebugServerProcess>
+    <ExternalSystemReattachDebugProcess>true</ExternalSystemReattachDebugProcess>
+    <DebugAllEnabled>false</DebugAllEnabled>
+    <method v="2" />
+  </configuration>
+</component>

.idea/runConfigurations/All_tests_in_briar_api.xml

@@ -0,0 +1,25 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests in briar-api" type="GradleRunConfiguration" factoryName="Gradle">
+    <ExternalSystemSettings>
+      <option name="executionName" />
+      <option name="externalProjectPath" value="$PROJECT_DIR$" />
+      <option name="externalSystemIdString" value="GRADLE" />
+      <option name="scriptParameters" value="" />
+      <option name="taskDescriptions">
+        <list />
+      </option>
+      <option name="taskNames">
+        <list>
+          <option value=":briar-api:animalSnifferMain" />
+          <option value=":briar-api:animalSnifferTest" />
+          <option value=":briar-api:test" />
+        </list>
+      </option>
+      <option name="vmOptions" value="" />
+    </ExternalSystemSettings>
+    <ExternalSystemDebugServerProcess>false</ExternalSystemDebugServerProcess>
+    <ExternalSystemReattachDebugProcess>true</ExternalSystemReattachDebugProcess>
+    <DebugAllEnabled>false</DebugAllEnabled>
+    <method v="2" />
+  </configuration>
+</component>

.idea/runConfigurations/All_tests_in_briar_core.xml

@@ -0,0 +1,25 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests in briar-core" type="GradleRunConfiguration" factoryName="Gradle">
+    <ExternalSystemSettings>
+      <option name="executionName" />
+      <option name="externalProjectPath" value="$PROJECT_DIR$" />
+      <option name="externalSystemIdString" value="GRADLE" />
+      <option name="scriptParameters" value="" />
+      <option name="taskDescriptions">
+        <list />
+      </option>
+      <option name="taskNames">
+        <list>
+          <option value=":briar-core:animalSnifferMain" />
+          <option value=":briar-core:animalSnifferTest" />
+          <option value=":briar-core:test" />
+        </list>
+      </option>
+      <option name="vmOptions" value="" />
+    </ExternalSystemSettings>
+    <ExternalSystemDebugServerProcess>false</ExternalSystemDebugServerProcess>
+    <ExternalSystemReattachDebugProcess>true</ExternalSystemReattachDebugProcess>
+    <DebugAllEnabled>false</DebugAllEnabled>
+    <method v="2" />
+  </configuration>
+</component>

.idea/runConfigurations/All_tests_in_briar_headless.xml

@@ -0,0 +1,23 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests in briar-headless" type="GradleRunConfiguration" factoryName="Gradle">
+    <ExternalSystemSettings>
+      <option name="executionName" />
+      <option name="externalProjectPath" value="$PROJECT_DIR$" />
+      <option name="externalSystemIdString" value="GRADLE" />
+      <option name="scriptParameters" value="" />
+      <option name="taskDescriptions">
+        <list />
+      </option>
+      <option name="taskNames">
+        <list>
+          <option value=":briar-headless:test" />
+        </list>
+      </option>
+      <option name="vmOptions" value="" />
+    </ExternalSystemSettings>
+    <ExternalSystemDebugServerProcess>false</ExternalSystemDebugServerProcess>
+    <ExternalSystemReattachDebugProcess>true</ExternalSystemReattachDebugProcess>
+    <DebugAllEnabled>false</DebugAllEnabled>
+    <method v="2" />
+  </configuration>
+</component>

.idea/runConfigurations/All_tests_in_mailbox_integration_tests.xml

@@ -0,0 +1,29 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All tests in mailbox-integration-tests" type="GradleRunConfiguration" factoryName="Gradle">
+    <ExternalSystemSettings>
+      <option name="env">
+        <map>
+          <entry key="MAILBOX_INTEGRATION_TESTS" value="true" />
+        </map>
+      </option>
+      <option name="executionName" />
+      <option name="externalProjectPath" value="$PROJECT_DIR$" />
+      <option name="externalSystemIdString" value="GRADLE" />
+      <option name="scriptParameters" value="" />
+      <option name="taskDescriptions">
+        <list />
+      </option>
+      <option name="taskNames">
+        <list>
+          <option value=":mailbox-integration-tests:test" />
+          <option value=":mailbox-integration-tests:cleanTest" />
+        </list>
+      </option>
+      <option name="vmOptions" value="" />
+    </ExternalSystemSettings>
+    <ExternalSystemDebugServerProcess>false</ExternalSystemDebugServerProcess>
+    <ExternalSystemReattachDebugProcess>true</ExternalSystemReattachDebugProcess>
+    <DebugAllEnabled>false</DebugAllEnabled>
+    <method v="2" />
+  </configuration>
+</component>

.idea/runConfigurations/Instrumentation_Tests__destroys_DB_.xml

@@ -0,0 +1,51 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Instrumentation Tests (destroys DB)" type="AndroidTestRunConfigurationType" factoryName="Android Instrumented Tests">
+    <module name="briar.briar-android" />
+    <option name="TESTING_TYPE" value="1" />
+    <option name="METHOD_NAME" value="" />
+    <option name="CLASS_NAME" value="" />
+    <option name="PACKAGE_NAME" value="org.briarproject.briar.android" />
+    <option name="INSTRUMENTATION_RUNNER_CLASS" value="" />
+    <option name="EXTRA_OPTIONS" value="-e notAnnotation androidx.test.filters.LargeTest" />
+    <option name="INCLUDE_GRADLE_EXTRA_OPTIONS" value="true" />
+    <option name="CLEAR_LOGCAT" value="false" />
+    <option name="SHOW_LOGCAT_AUTOMATICALLY" value="false" />
+    <option name="SKIP_NOOP_APK_INSTALLATIONS" value="true" />
+    <option name="FORCE_STOP_RUNNING_APP" value="true" />
+    <option name="TARGET_SELECTION_MODE" value="DEVICE_AND_SNAPSHOT_COMBO_BOX" />
+    <option name="DEBUGGER_TYPE" value="Auto" />
+    <Auto>
+      <option name="USE_JAVA_AWARE_DEBUGGER" value="false" />
+      <option name="SHOW_STATIC_VARS" value="true" />
+      <option name="WORKING_DIR" value="" />
+      <option name="TARGET_LOGGING_CHANNELS" value="lldb process:gdb-remote packets" />
+      <option name="SHOW_OPTIMIZED_WARNING" value="true" />
+    </Auto>
+    <Hybrid>
+      <option name="USE_JAVA_AWARE_DEBUGGER" value="false" />
+      <option name="SHOW_STATIC_VARS" value="true" />
+      <option name="WORKING_DIR" value="" />
+      <option name="TARGET_LOGGING_CHANNELS" value="lldb process:gdb-remote packets" />
+      <option name="SHOW_OPTIMIZED_WARNING" value="true" />
+    </Hybrid>
+    <Java />
+    <Native>
+      <option name="USE_JAVA_AWARE_DEBUGGER" value="false" />
+      <option name="SHOW_STATIC_VARS" value="true" />
+      <option name="WORKING_DIR" value="" />
+      <option name="TARGET_LOGGING_CHANNELS" value="lldb process:gdb-remote packets" />
+      <option name="SHOW_OPTIMIZED_WARNING" value="true" />
+    </Native>
+    <Profilers>
+      <option name="ADVANCED_PROFILING_ENABLED" value="false" />
+      <option name="STARTUP_PROFILING_ENABLED" value="false" />
+      <option name="STARTUP_CPU_PROFILING_ENABLED" value="false" />
+      <option name="STARTUP_CPU_PROFILING_CONFIGURATION_NAME" value="Sample Java Methods" />
+      <option name="STARTUP_NATIVE_MEMORY_PROFILING_ENABLED" value="false" />
+      <option name="NATIVE_MEMORY_SAMPLE_RATE_BYTES" value="2048" />
+    </Profilers>
+    <method v="2">
+      <option name="Android.Gradle.BeforeRunTask" enabled="true" />
+    </method>
+  </configuration>
+</component>

.idea/runConfigurations/briar_headless.xml

@@ -0,0 +1,16 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="briar-headless" type="JetRunConfigurationType" singleton="true">
+    <module name="briar.briar-headless" />
+    <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="" />
+    <method v="2">
+      <option name="Make" enabled="true" />
+      <option name="Gradle.BeforeRunTask" enabled="true" tasks="jar" externalProjectPath="$PROJECT_DIR$/briar-headless" vmOptions="" scriptParameters="" />
+    </method>
+  </configuration>
+</component>

CONTRIBUTING.md

@@ -0,0 +1,10 @@
+Folder-Description:
+===================
+* `briar-*`: Specifically for the Briar app (Phone/Desktop/Headless)
+* `bramble-*`: The protocol stack - not necessarily Briar-dependent
+
+---
+
+* `*-api`: public stuff that can be referenced from other packages and modules - mostly interfaces + a few utility classes
+* `*-core`: implementations of api that are portable across Android/Desktop/Headless
+* `*-java`: implementations of api that are specific to Desktop & Headless

LICENSE.txt

@@ -13,23 +13,6 @@
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
--------------------------------------------------------------------------
-
-    All files under the directories briar-android/src, briar-api/src,
-    briar-core/src, briar-desktop/src and briar-test/src are licensed
-    under the Apache License, version 2.0 (the "License"); you may not
-    use these files except in compliance with the License.
-
-    You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-    Unless required by applicable law or agreed to in writing, software
-    distributed under the License is distributed on an "AS IS" BASIS,
-    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-    implied. See the License for the specific language governing
-    permissions and limitations under the License.
-
 -------------------------------------------------------------------------
 
                     GNU GENERAL PUBLIC LICENSE

README.md

@@ -1 +1,37 @@
-Briar is a messaging app designed for activists, journalists, and anyone else who needs a safe, easy and robust way to communicate. Unlike traditional messaging tools such as email, Twitter or Telegram, Briar doesn't rely on a central server - messages are synchronized directly between the users' devices. If the Internet's down, Briar can sync via Bluetooth or Wi-Fi, keeping the information flowing in a crisis. If the Internet's up, Briar can sync via the Tor network, protecting users and their relationships from surveillance.
+# Briar
+Briar is a messaging app designed for activists, journalists, and anyone else who needs a safe, easy and robust way to communicate.
+
+Unlike traditional messaging tools such as email, Twitter or Telegram, Briar doesn't rely on a central server - messages are synchronized directly between the users' devices. 
+
+If the Internet's down, Briar can sync via Bluetooth or Wi-Fi, keeping information flowing in a crisis. If the Internet's up, Briar can sync via the Tor network, protecting users and their relationships from surveillance.
+
+## Download Briar
+
+[<img src="https://briarproject.org//img/fdroid_badge.png"  width="240">](https://briarproject.org/fdroid)
+[<img src="https://briarproject.org/img/google_play_badge_web_generic.png"  width="240">](https://play.google.com/store/apps/details?id=org.briarproject.briar.android)
+
+You can also [download the APK file](https://briarproject.org/apk) directly from
+our site.
+
+## Useful links
+[briarproject.org](https://briarproject.org/)
+
+[Source code](https://code.briarproject.org/briar/briar/tree/master)
+
+[Manual](https://briarproject.org/manual/)
+
+[Wiki](https://code.briarproject.org/briar/briar/-/wikis/home)
+
+## Reproducible builds
+
+We provide [docker images](https://code.briarproject.org/briar/briar-reproducer#briar-reproducer)
+to ease the task of verifying that the published APK binaries
+include nothing but our publicly available source code.
+
+You can either use those images or use them as a blueprint to build your own environment
+for reproduction.
+
+## Donate
+
+[![Donate using Liberapay](https://briarproject.org/img/liberapay.svg)](https://liberapay.com/Briar/donate) [![Flattr this](https://briarproject.org/img/flattr-badge-large.png "Flattr this")](https://flattr.com/t/592836/)   
+Bitcoin and BCH: 1NZCKkUCtJV2U2Y9hDb9uq8S7ksFCFGR6K

TRANSLATION.md

@@ -0,0 +1,9 @@
+Translations for this project are managed through Transifex:
+
+https://transifex.com/otf/briar
+
+If you'd like to volunteer as a translator, please create a Transifex account and request to be
+added to the project's translation team. The Localization Lab has some instructions and advice for
+translators here:
+
+https://wiki.localizationlab.org/index.php/Briar

bramble-android/.gitignore

@@ -0,0 +1,6 @@
+bin
+gen
+build
+.settings
+src/main/res/raw/*.zip
+src/main/jniLibs

bramble-android/build.gradle

@@ -0,0 +1,94 @@
+apply plugin: 'com.android.library'
+apply plugin: 'witness'
+apply from: 'witness.gradle'
+
+android {
+	compileSdkVersion 33
+	buildToolsVersion '33.0.0'
+
+	packagingOptions {
+		doNotStrip '**/*.so'
+	}
+
+	defaultConfig {
+		minSdkVersion 21
+		targetSdkVersion 33
+		versionCode 10504
+		versionName "1.5.4"
+		consumerProguardFiles 'proguard-rules.txt'
+
+		testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+		testInstrumentationRunnerArguments disableAnalytics: 'true'
+	}
+
+	compileOptions {
+		sourceCompatibility JavaVersion.VERSION_1_8
+		targetCompatibility JavaVersion.VERSION_1_8
+	}
+
+	lintOptions {
+		// FIXME
+		warning "LintError"
+		warning "InvalidPackage"
+		warning "MissingPermission"
+		warning "InlinedApi", "ObsoleteSdkInt", "Override", "NewApi", "UnusedAttribute"
+	}
+}
+
+configurations {
+	tor
+}
+
+dependencies {
+	api 'org.briarproject:dont-kill-me-lib:0.2.7'
+
+	// In theory this dependency shouldn't be needed, but without it Android Studio's linter will
+	// complain about unresolved symbols for bramble-api test classes in bramble-android tests,
+	// even though the bramble-api test classes are provided by the testImplementation dependency
+	// below and the compiler can find them
+	implementation project(':bramble-api')
+
+	implementation project(':bramble-core')
+
+	implementation 'androidx.annotation:annotation:1.5.0'
+	implementation "org.briarproject:onionwrapper-android:$onionwrapper_version"
+
+	tor "org.briarproject:tor-android:$tor_version"
+	tor "org.briarproject:obfs4proxy-android:$obfs4proxy_version"
+	tor "org.briarproject:snowflake-android:$snowflake_version"
+
+	annotationProcessor "com.google.dagger:dagger-compiler:$dagger_version"
+
+	compileOnly 'javax.annotation:jsr250-api:1.0'
+
+	testImplementation project(path: ':bramble-api', configuration: 'testOutput')
+
+	testImplementation "junit:junit:$junit_version"
+	testImplementation "org.jmock:jmock:$jmock_version"
+	testImplementation "org.jmock:jmock-junit4:$jmock_version"
+	testImplementation "org.jmock:jmock-imposters:$jmock_version"
+}
+
+def torLibsDir = 'src/main/jniLibs'
+
+task cleanTorBinaries {
+	outputs.dir torLibsDir
+	doLast {
+		delete fileTree(torLibsDir)
+	}
+}
+
+clean.dependsOn cleanTorBinaries
+
+task unpackTorBinaries {
+	outputs.dir torLibsDir
+	doLast {
+		copy {
+			from configurations.tor.collect { zipTree(it) }
+			into torLibsDir
+		}
+	}
+	dependsOn cleanTorBinaries
+}
+
+preBuild.dependsOn unpackTorBinaries

bramble-android/proguard-rules.txt

@@ -0,0 +1,24 @@
+# Keep the H2 classes that are loaded via reflection
+-keep class org.h2.Driver { *; }
+-keep class org.h2.engine.Engine { *; }
+-keep class org.h2.store.fs.** { *; }
+# Don't warn about unused dependencies of H2 classes
+-dontwarn org.h2.**
+-dontnote org.h2.**
+
+-keep class dagger.** { *; }
+-dontwarn dagger.**
+-dontnote dagger.**
+
+-keep class net.i2p.crypto.eddsa.** { *; }
+
+-keep class org.whispersystems.curve25519.** { *; }
+
+-dontwarn sun.misc.Unsafe
+-dontnote com.google.common.**
+
+-dontwarn com.fasterxml.jackson.databind.ext.Java7SupportImpl
+
+# Keep all Jackson-serialisable classes and their members
+-keep interface com.fasterxml.jackson.databind.annotation.JsonSerialize
+-keep @com.fasterxml.jackson.databind.annotation.JsonSerialize class * { *; }

bramble-android/src/main/AndroidManifest.xml

@@ -0,0 +1,36 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:tools="http://schemas.android.com/tools"
+	package="org.briarproject.bramble">
+
+	<uses-feature
+		android:name="android.hardware.bluetooth"
+		android:required="false" />
+
+	<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+	<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
+	<!-- The BLUETOOTH permission was supposed to be removed in API 31 but is still needed on some Xiaomi/Redmi/POCO devices running API 31 and Nubia devices running API 32 -->
+	<uses-permission
+		android:name="android.permission.BLUETOOTH"
+		android:maxSdkVersion="32" />
+	<uses-permission
+		android:name="android.permission.BLUETOOTH_ADMIN"
+		android:maxSdkVersion="30" />
+	<uses-permission
+		android:name="android.permission.BLUETOOTH_SCAN"
+		android:usesPermissionFlags="neverForLocation"
+		tools:targetApi="31" />
+	<uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
+	<uses-permission android:name="android.permission.BLUETOOTH_ADVERTISE" />
+	<uses-permission android:name="android.permission.INTERNET" />
+	<uses-permission android:name="android.permission.WAKE_LOCK" />
+
+	<application
+		android:allowBackup="false"
+		android:label="@string/app_name"
+		android:supportsRtl="true">
+
+		<receiver android:name=".system.AlarmReceiver" />
+
+	</application>
+
+</manifest>

bramble-android/src/main/java/org/briarproject/bramble/BrambleAndroidEagerSingletons.java

@@ -0,0 +1,24 @@
+package org.briarproject.bramble;
+
+import org.briarproject.bramble.battery.AndroidBatteryModule;
+import org.briarproject.bramble.network.AndroidNetworkModule;
+import org.briarproject.bramble.reporting.ReportingModule;
+
+public interface BrambleAndroidEagerSingletons {
+
+	void inject(AndroidBatteryModule.EagerSingletons init);
+
+	void inject(AndroidNetworkModule.EagerSingletons init);
+
+	void inject(ReportingModule.EagerSingletons init);
+
+	class Helper {
+
+		public static void injectEagerSingletons(
+				BrambleAndroidEagerSingletons c) {
+			c.inject(new AndroidBatteryModule.EagerSingletons());
+			c.inject(new AndroidNetworkModule.EagerSingletons());
+			c.inject(new ReportingModule.EagerSingletons());
+		}
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/BrambleAndroidModule.java

@@ -0,0 +1,31 @@
+package org.briarproject.bramble;
+
+import org.briarproject.bramble.battery.AndroidBatteryModule;
+import org.briarproject.bramble.io.DnsModule;
+import org.briarproject.bramble.network.AndroidNetworkModule;
+import org.briarproject.bramble.plugin.tor.CircumventionModule;
+import org.briarproject.bramble.reporting.ReportingModule;
+import org.briarproject.bramble.socks.SocksModule;
+import org.briarproject.bramble.system.AndroidSystemModule;
+import org.briarproject.bramble.system.AndroidTaskSchedulerModule;
+import org.briarproject.bramble.system.AndroidWakeLockModule;
+import org.briarproject.bramble.system.AndroidWakefulIoExecutorModule;
+import org.briarproject.bramble.system.DefaultThreadFactoryModule;
+
+import dagger.Module;
+
+@Module(includes = {
+		AndroidBatteryModule.class,
+		AndroidNetworkModule.class,
+		AndroidSystemModule.class,
+		AndroidTaskSchedulerModule.class,
+		AndroidWakefulIoExecutorModule.class,
+		AndroidWakeLockModule.class,
+		DefaultThreadFactoryModule.class,
+		CircumventionModule.class,
+		DnsModule.class,
+		ReportingModule.class,
+		SocksModule.class
+})
+public class BrambleAndroidModule {
+}

bramble-android/src/main/java/org/briarproject/bramble/BrambleAppComponent.java

@@ -0,0 +1,8 @@
+package org.briarproject.bramble;
+
+import org.briarproject.bramble.api.system.AlarmListener;
+
+public interface BrambleAppComponent {
+
+	AlarmListener alarmListener();
+}

bramble-android/src/main/java/org/briarproject/bramble/BrambleApplication.java

@@ -0,0 +1,6 @@
+package org.briarproject.bramble;
+
+public interface BrambleApplication {
+
+	BrambleAppComponent getBrambleAppComponent();
+}

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

@@ -0,0 +1,132 @@
+package org.briarproject.bramble.account;
+
+import android.app.Application;
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.preference.PreferenceManager;
+
+import org.briarproject.bramble.api.account.AccountManager;
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.db.DatabaseConfig;
+import org.briarproject.bramble.api.identity.IdentityManager;
+
+import java.io.File;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.GuardedBy;
+import javax.inject.Inject;
+
+import static java.util.Arrays.asList;
+import static java.util.logging.Level.INFO;
+import static org.briarproject.bramble.util.IoUtils.deleteFileOrDir;
+import static org.briarproject.bramble.util.LogUtils.logFileOrDir;
+
+class AndroidAccountManager extends AccountManagerImpl
+		implements AccountManager {
+
+	private static final Logger LOG =
+			Logger.getLogger(AndroidAccountManager.class.getName());
+
+	/**
+	 * Directories that shouldn't be deleted when deleting the user's account.
+	 */
+	private static final List<String> PROTECTED_DIR_NAMES =
+			asList("cache", "code_cache", "lib", "shared_prefs");
+
+	protected final Context appContext;
+	private final SharedPreferences prefs;
+
+	@Inject
+	AndroidAccountManager(DatabaseConfig databaseConfig,
+			CryptoComponent crypto, IdentityManager identityManager,
+			SharedPreferences prefs, Application app) {
+		super(databaseConfig, crypto, identityManager);
+		this.prefs = prefs;
+		appContext = app.getApplicationContext();
+	}
+
+	@Override
+	public boolean accountExists() {
+		boolean exists = super.accountExists();
+		if (!exists && LOG.isLoggable(INFO)) {
+			LOG.info("Account does not exist. Contents of account directory:");
+			logFileOrDir(LOG, INFO, getDataDir());
+		}
+		return exists;
+	}
+
+	@Override
+	public void deleteAccount() {
+		synchronized (stateChangeLock) {
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Contents of account directory before deleting:");
+				logFileOrDir(LOG, INFO, getDataDir());
+			}
+			super.deleteAccount();
+			SharedPreferences defaultPrefs = getDefaultSharedPreferences();
+			deleteAppData(prefs, defaultPrefs);
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Contents of account directory after deleting:");
+				logFileOrDir(LOG, INFO, getDataDir());
+			}
+		}
+	}
+
+	// Package access for testing
+	SharedPreferences getDefaultSharedPreferences() {
+		return PreferenceManager.getDefaultSharedPreferences(appContext);
+	}
+
+	@GuardedBy("stateChangeLock")
+	private void deleteAppData(SharedPreferences... clear) {
+		// Clear and commit shared preferences
+		for (SharedPreferences prefs : clear) {
+			if (!prefs.edit().clear().commit())
+				LOG.warning("Could not clear shared preferences");
+		}
+		// Delete files, except protected directories
+		Set<File> files = new HashSet<>();
+		File dataDir = getDataDir();
+		@Nullable
+		File[] fileArray = dataDir.listFiles();
+		if (fileArray == null) {
+			LOG.warning("Could not list files in app data dir");
+		} else {
+			for (File file : fileArray) {
+				if (!PROTECTED_DIR_NAMES.contains(file.getName())) {
+					files.add(file);
+				}
+			}
+		}
+		files.add(appContext.getFilesDir());
+		addIfNotNull(files, appContext.getExternalCacheDir());
+		for (File file : appContext.getExternalCacheDirs()) {
+			addIfNotNull(files, file);
+		}
+		for (File file : appContext.getExternalMediaDirs()) {
+			addIfNotNull(files, file);
+		}
+		// Clear the cache directory but don't delete it
+		File cacheDir = appContext.getCacheDir();
+		File[] children = cacheDir.listFiles();
+		if (children != null) files.addAll(asList(children));
+		for (File file : files) {
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Deleting " + file.getAbsolutePath());
+			}
+			deleteFileOrDir(file);
+		}
+	}
+
+	private File getDataDir() {
+		return new File(appContext.getApplicationInfo().dataDir);
+	}
+
+	private void addIfNotNull(Set<File> files, @Nullable File file) {
+		if (file != null) files.add(file);
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/api/system/AlarmListener.java

@@ -0,0 +1,11 @@
+package org.briarproject.bramble.api.system;
+
+import android.content.Intent;
+
+import org.briarproject.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface AlarmListener {
+
+	void onAlarm(Intent intent);
+}

bramble-android/src/main/java/org/briarproject/bramble/api/system/AndroidExecutor.java

@@ -0,0 +1,33 @@
+package org.briarproject.bramble.api.system;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.Future;
+
+/**
+ * Enables background threads to make Android API calls that must be made from
+ * a thread with a message queue.
+ */
+public interface AndroidExecutor {
+
+	/**
+	 * Runs the given task on a background thread with a message queue and
+	 * returns a Future for getting the result.
+	 */
+	<V> Future<V> runOnBackgroundThread(Callable<V> c);
+
+	/**
+	 * Runs the given task on a background thread with a message queue.
+	 */
+	void runOnBackgroundThread(Runnable r);
+
+	/**
+	 * Runs the given task on the main UI thread and returns a Future for
+	 * getting the result.
+	 */
+	<V> Future<V> runOnUiThread(Callable<V> c);
+
+	/**
+	 * Runs the given task on the main UI thread.
+	 */
+	void runOnUiThread(Runnable r);
+}

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

@@ -0,0 +1,122 @@
+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 android.os.PowerManager;
+
+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 androidx.annotation.RequiresApi;
+
+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.EXTRA_PLUGGED;
+import static android.os.Build.VERSION.SDK_INT;
+import static android.os.PowerManager.ACTION_DEVICE_IDLE_MODE_CHANGED;
+import static android.os.PowerManager.ACTION_DEVICE_LIGHT_IDLE_MODE_CHANGED;
+import static android.os.PowerManager.ACTION_LOW_POWER_STANDBY_ENABLED_CHANGED;
+import static android.os.PowerManager.ACTION_POWER_SAVE_MODE_CHANGED;
+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_PLUGGED, 0);
+		return status != 0;
+	}
+
+	@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);
+		filter.addAction(ACTION_POWER_SAVE_MODE_CHANGED);
+		if (SDK_INT >= 23) filter.addAction(ACTION_DEVICE_IDLE_MODE_CHANGED);
+		if (SDK_INT >= 33) {
+			filter.addAction(ACTION_LOW_POWER_STANDBY_ENABLED_CHANGED);
+			filter.addAction(ACTION_DEVICE_LIGHT_IDLE_MODE_CHANGED);
+		}
+		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));
+			else if (SDK_INT >= 23 &&
+					ACTION_DEVICE_IDLE_MODE_CHANGED.equals(action) &&
+					LOG.isLoggable(INFO)) {
+				LOG.info("Device idle mode changed to: " +
+						getPowerManager(ctx).isDeviceIdleMode());
+			} else if (SDK_INT >= 23 &&
+					ACTION_POWER_SAVE_MODE_CHANGED.equals(action) &&
+					LOG.isLoggable(INFO)) {
+				LOG.info("Power save mode changed to: " +
+						getPowerManager(ctx).isPowerSaveMode());
+			} else if (SDK_INT >= 33 && LOG.isLoggable(INFO) &&
+					ACTION_LOW_POWER_STANDBY_ENABLED_CHANGED.equals(action)) {
+				PowerManager powerManager =
+						ctx.getSystemService(PowerManager.class);
+				LOG.info("Low power standby now is: " +
+						powerManager.isLowPowerStandbyEnabled());
+			} else if (SDK_INT >= 33 && LOG.isLoggable(INFO) &&
+					ACTION_DEVICE_LIGHT_IDLE_MODE_CHANGED.equals(action)) {
+				PowerManager powerManager = getPowerManager(ctx);
+				LOG.info("Light idle mode now is: " +
+						powerManager.isDeviceLightIdleMode());
+			}
+		}
+	}
+
+	@RequiresApi(api = 23)
+	private PowerManager getPowerManager(Context ctx) {
+		return ctx.getSystemService(PowerManager.class);
+	}
+}

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

@@ -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;
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/network/AndroidNetworkManager.java

@@ -0,0 +1,260 @@
+package org.briarproject.bramble.network;
+
+import android.annotation.TargetApi;
+import android.app.Application;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.net.ConnectivityManager;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
+import android.net.Network;
+import android.net.NetworkInfo;
+import android.net.wifi.WifiInfo;
+import android.net.wifi.WifiManager;
+
+import org.briarproject.bramble.api.Cancellable;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventExecutor;
+import org.briarproject.bramble.api.lifecycle.Service;
+import org.briarproject.bramble.api.network.NetworkManager;
+import org.briarproject.bramble.api.network.NetworkStatus;
+import org.briarproject.bramble.api.network.event.NetworkStatusEvent;
+import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.nullsafety.ParametersNotNullByDefault;
+
+import java.net.Inet4Address;
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.net.SocketException;
+import java.util.Enumeration;
+import java.util.concurrent.Executor;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+
+import static android.content.Context.CONNECTIVITY_SERVICE;
+import static android.content.Context.WIFI_SERVICE;
+import static android.content.Intent.ACTION_SCREEN_OFF;
+import static android.content.Intent.ACTION_SCREEN_ON;
+import static android.net.ConnectivityManager.CONNECTIVITY_ACTION;
+import static android.net.ConnectivityManager.TYPE_WIFI;
+import static android.net.wifi.p2p.WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION;
+import static android.os.Build.VERSION.SDK_INT;
+import static android.os.PowerManager.ACTION_DEVICE_IDLE_MODE_CHANGED;
+import static java.net.NetworkInterface.getNetworkInterfaces;
+import static java.util.Collections.list;
+import static java.util.concurrent.TimeUnit.MINUTES;
+import static java.util.concurrent.TimeUnit.SECONDS;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.LogUtils.logException;
+import static org.briarproject.nullsafety.NullSafety.requireNonNull;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+class AndroidNetworkManager implements NetworkManager, Service {
+
+	private static final Logger LOG =
+			getLogger(AndroidNetworkManager.class.getName());
+
+	// See android.net.wifi.WifiManager
+	private static final String WIFI_AP_STATE_CHANGED_ACTION =
+			"android.net.wifi.WIFI_AP_STATE_CHANGED";
+
+	private final TaskScheduler scheduler;
+	private final EventBus eventBus;
+	private final Executor eventExecutor;
+	private final Application app;
+	private final ConnectivityManager connectivityManager;
+	private final AtomicReference<Cancellable> connectivityCheck =
+			new AtomicReference<>();
+	private final AtomicBoolean used = new AtomicBoolean(false);
+
+	private volatile BroadcastReceiver networkStateReceiver = null;
+
+	@Inject
+	AndroidNetworkManager(TaskScheduler scheduler, EventBus eventBus,
+			@EventExecutor Executor eventExecutor, Application app) {
+		this.scheduler = scheduler;
+		this.eventBus = eventBus;
+		this.eventExecutor = eventExecutor;
+		this.app = app;
+		connectivityManager = (ConnectivityManager)
+				requireNonNull(app.getSystemService(CONNECTIVITY_SERVICE));
+	}
+
+	@Override
+	public void startService() {
+		if (used.getAndSet(true)) throw new IllegalStateException();
+		// Register to receive network status events
+		networkStateReceiver = new NetworkStateReceiver();
+		IntentFilter filter = new IntentFilter();
+		filter.addAction(CONNECTIVITY_ACTION);
+		filter.addAction(ACTION_SCREEN_ON);
+		filter.addAction(ACTION_SCREEN_OFF);
+		filter.addAction(WIFI_AP_STATE_CHANGED_ACTION);
+		filter.addAction(WIFI_P2P_THIS_DEVICE_CHANGED_ACTION);
+		if (SDK_INT >= 23) filter.addAction(ACTION_DEVICE_IDLE_MODE_CHANGED);
+		app.registerReceiver(networkStateReceiver, filter);
+	}
+
+	@Override
+	public void stopService() {
+		if (networkStateReceiver != null)
+			app.unregisterReceiver(networkStateReceiver);
+	}
+
+	@Override
+	public NetworkStatus getNetworkStatus() {
+		// https://issuetracker.google.com/issues/175055271
+		try {
+			NetworkInfo net = connectivityManager.getActiveNetworkInfo();
+			boolean connected = net != null && net.isConnected();
+			// Research into Android's behavior to check network connectivity
+			// (https://code.briarproject.org/briar/public-mesh-research/-/issues/19)
+			// has shown that NetworkInfo#isConnected() returns true if the device
+			// is connected to any Wifi, independent of whether any specific IP
+			// address can be reached using it or any domain names can be resolved.
+			boolean wifi = false, ipv6Only = false;
+			if (connected) {
+				wifi = net.getType() == TYPE_WIFI;
+				if (SDK_INT >= 23) ipv6Only = isActiveNetworkIpv6Only();
+				else ipv6Only = areAllAvailableNetworksIpv6Only();
+			}
+			return new NetworkStatus(connected, wifi, ipv6Only);
+		} catch (SecurityException e) {
+			logException(LOG, WARNING, e);
+			// Without the ConnectivityManager we can't detect whether we have
+			// internet access. Assume we do, which is probably less harmful
+			// than assuming we don't. Likewise, assume the connection is
+			// IPv6-only. Fall back to the WifiManager to detect whether we
+			// have a wifi connection.
+			LOG.info("ConnectivityManager is broken, guessing connectivity");
+			boolean connected = true, wifi = false, ipv6Only = true;
+			WifiManager wm = (WifiManager) app.getSystemService(WIFI_SERVICE);
+			if (wm != null) {
+				WifiInfo info = wm.getConnectionInfo();
+				if (info != null && info.getIpAddress() != 0) {
+					LOG.info("Connected to wifi");
+					wifi = true;
+					ipv6Only = false;
+				}
+			}
+			return new NetworkStatus(connected, wifi, ipv6Only);
+		}
+	}
+
+	/**
+	 * Returns true if the
+	 * {@link ConnectivityManager#getActiveNetwork() active network} has an
+	 * IPv6 unicast address and no IPv4 addresses. The active network is
+	 * assumed not to be a loopback interface.
+	 */
+	@TargetApi(23)
+	private boolean isActiveNetworkIpv6Only() {
+		// https://issuetracker.google.com/issues/175055271
+		try {
+			Network net = connectivityManager.getActiveNetwork();
+			if (net == null) {
+				LOG.info("No active network");
+				return false;
+			}
+			LinkProperties props = connectivityManager.getLinkProperties(net);
+			if (props == null) {
+				LOG.info("No link properties for active network");
+				return false;
+			}
+			boolean hasIpv6Unicast = false;
+			for (LinkAddress linkAddress : props.getLinkAddresses()) {
+				InetAddress addr = linkAddress.getAddress();
+				if (addr instanceof Inet4Address) return false;
+				if (!addr.isMulticastAddress()) hasIpv6Unicast = true;
+			}
+			return hasIpv6Unicast;
+		} catch (SecurityException e) {
+			logException(LOG, WARNING, e);
+			return false;
+		}
+	}
+
+	/**
+	 * Returns true if the device has at least one network interface with an
+	 * IPv6 unicast address and no interfaces with IPv4 addresses, excluding
+	 * loopback interfaces and interfaces that are
+	 * {@link NetworkInterface#isUp() down}. If this method returns true and
+	 * the device has internet access then it's via IPv6 only.
+	 */
+	private boolean areAllAvailableNetworksIpv6Only() {
+		try {
+			Enumeration<NetworkInterface> interfaces = getNetworkInterfaces();
+			if (interfaces == null) {
+				LOG.info("No network interfaces");
+				return false;
+			}
+			boolean hasIpv6Unicast = false;
+			for (NetworkInterface i : list(interfaces)) {
+				if (i.isLoopback() || !i.isUp()) continue;
+				for (InetAddress addr : list(i.getInetAddresses())) {
+					if (addr instanceof Inet4Address) return false;
+					if (!addr.isMulticastAddress()) hasIpv6Unicast = true;
+				}
+			}
+			return hasIpv6Unicast;
+		} catch (SocketException e) {
+			logException(LOG, WARNING, e);
+			return false;
+		}
+	}
+
+	private void updateConnectionStatus() {
+		eventBus.broadcast(new NetworkStatusEvent(getNetworkStatus()));
+	}
+
+	private void scheduleConnectionStatusUpdate(int delay, TimeUnit unit) {
+		Cancellable newConnectivityCheck =
+				scheduler.schedule(this::updateConnectionStatus, eventExecutor,
+						delay, unit);
+		Cancellable oldConnectivityCheck =
+				connectivityCheck.getAndSet(newConnectivityCheck);
+		if (oldConnectivityCheck != null) oldConnectivityCheck.cancel();
+	}
+
+	private class NetworkStateReceiver extends BroadcastReceiver {
+
+		@Override
+		public void onReceive(Context ctx, Intent i) {
+			String action = i.getAction();
+			if (LOG.isLoggable(INFO)) LOG.info("Received broadcast " + action);
+			updateConnectionStatus();
+			if (isSleepOrDozeEvent(action)) {
+				// Allow time for the network to be enabled or disabled
+				scheduleConnectionStatusUpdate(1, MINUTES);
+			} else if (isApEvent(action)) {
+				// The state change may be broadcast before the AP address is
+				// visible, so delay handling the event
+				scheduleConnectionStatusUpdate(5, SECONDS);
+			}
+		}
+
+		private boolean isSleepOrDozeEvent(@Nullable String action) {
+			boolean isSleep = ACTION_SCREEN_ON.equals(action) ||
+					ACTION_SCREEN_OFF.equals(action);
+			boolean isDoze = SDK_INT >= 23 &&
+					ACTION_DEVICE_IDLE_MODE_CHANGED.equals(action);
+			return isSleep || isDoze;
+		}
+
+		private boolean isApEvent(@Nullable String action) {
+			return WIFI_AP_STATE_CHANGED_ACTION.equals(action) ||
+					WIFI_P2P_THIS_DEVICE_CHANGED_ACTION.equals(action);
+		}
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/network/AndroidNetworkModule.java

@@ -0,0 +1,27 @@
+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;
+import dagger.Provides;
+
+@Module
+public class AndroidNetworkModule {
+
+	public static class EagerSingletons {
+		@Inject
+		NetworkManager networkManager;
+	}
+
+	@Provides
+	@Singleton
+	NetworkManager provideNetworkManager(LifecycleManager lifecycleManager,
+			AndroidNetworkManager networkManager) {
+		lifecycleManager.registerService(networkManager);
+		return networkManager;
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/plugin/bluetooth/AndroidBluetoothConnectionFactory.java

@@ -0,0 +1,36 @@
+package org.briarproject.bramble.plugin.bluetooth;
+
+import android.bluetooth.BluetoothSocket;
+
+import org.briarproject.android.dontkillmelib.wakelock.AndroidWakeLockManager;
+import org.briarproject.bramble.api.io.TimeoutMonitor;
+import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.io.IOException;
+
+@NotNullByDefault
+class AndroidBluetoothConnectionFactory
+		implements BluetoothConnectionFactory<BluetoothSocket> {
+
+	private final BluetoothConnectionLimiter connectionLimiter;
+	private final AndroidWakeLockManager wakeLockManager;
+	private final TimeoutMonitor timeoutMonitor;
+
+	AndroidBluetoothConnectionFactory(
+			BluetoothConnectionLimiter connectionLimiter,
+			AndroidWakeLockManager wakeLockManager,
+			TimeoutMonitor timeoutMonitor) {
+		this.connectionLimiter = connectionLimiter;
+		this.wakeLockManager = wakeLockManager;
+		this.timeoutMonitor = timeoutMonitor;
+	}
+
+	@Override
+	public DuplexTransportConnection wrapSocket(DuplexPlugin plugin,
+			BluetoothSocket s) throws IOException {
+		return new AndroidBluetoothTransportConnection(plugin,
+				connectionLimiter, wakeLockManager, timeoutMonitor, s);
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/plugin/bluetooth/AndroidBluetoothPlugin.java

@@ -0,0 +1,315 @@
+package org.briarproject.bramble.plugin.bluetooth;
+
+import android.annotation.SuppressLint;
+import android.app.Application;
+import android.bluetooth.BluetoothAdapter;
+import android.bluetooth.BluetoothDevice;
+import android.bluetooth.BluetoothServerSocket;
+import android.bluetooth.BluetoothSocket;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+
+import org.briarproject.bramble.api.plugin.Backoff;
+import org.briarproject.bramble.api.plugin.PluginCallback;
+import org.briarproject.bramble.api.plugin.PluginException;
+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 org.briarproject.bramble.util.IoUtils;
+import org.briarproject.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.nullsafety.ParametersNotNullByDefault;
+
+import java.io.IOException;
+import java.security.SecureRandom;
+import java.util.ArrayList;
+import java.util.Collection;
+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;
+import static android.bluetooth.BluetoothAdapter.EXTRA_STATE;
+import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE;
+import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE;
+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.DEVICE_TYPE_LE;
+import static android.bluetooth.BluetoothDevice.EXTRA_DEVICE;
+import static java.util.Collections.shuffle;
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.AndroidUtils.hasBtConnectPermission;
+import static org.briarproject.bramble.util.PrivacyUtils.scrubMacAddress;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+@SuppressLint("MissingPermission")
+class AndroidBluetoothPlugin extends
+		AbstractBluetoothPlugin<BluetoothSocket, BluetoothServerSocket> {
+
+	private static final Logger LOG =
+			getLogger(AndroidBluetoothPlugin.class.getName());
+
+	private static final int MAX_DISCOVERY_MS = 10_000;
+
+	private final AndroidExecutor androidExecutor;
+	private final Application app;
+	private final Clock clock;
+
+	private volatile BluetoothStateReceiver receiver = null;
+
+	// Non-null if the plugin started successfully
+	private volatile BluetoothAdapter adapter = null;
+	private volatile boolean stopDiscoverAndConnect;
+
+	AndroidBluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
+			BluetoothConnectionFactory<BluetoothSocket> connectionFactory,
+			Executor ioExecutor,
+			Executor wakefulIoExecutor,
+			SecureRandom secureRandom,
+			AndroidExecutor androidExecutor,
+			Application app,
+			Clock clock,
+			Backoff backoff,
+			PluginCallback callback,
+			long maxLatency,
+			int maxIdleTime) {
+		super(connectionLimiter, connectionFactory, ioExecutor,
+				wakefulIoExecutor, secureRandom, backoff, callback,
+				maxLatency, maxIdleTime);
+		this.androidExecutor = androidExecutor;
+		this.app = app;
+		this.clock = clock;
+	}
+
+	@Override
+	protected boolean isBluetoothAccessible() {
+		return hasBtConnectPermission(app);
+	}
+
+	@Override
+	public void start() throws PluginException {
+		super.start();
+		// Listen for changes to the Bluetooth state
+		IntentFilter filter = new IntentFilter();
+		filter.addAction(ACTION_STATE_CHANGED);
+		filter.addAction(ACTION_SCAN_MODE_CHANGED);
+		receiver = new BluetoothStateReceiver();
+		app.registerReceiver(receiver, filter);
+	}
+
+	@Override
+	public void stop() {
+		super.stop();
+		if (receiver != null) app.unregisterReceiver(receiver);
+	}
+
+	@Override
+	void initialiseAdapter() throws IOException {
+		// BluetoothAdapter.getDefaultAdapter() must be called on a thread
+		// with a message queue, so submit it to the AndroidExecutor
+		try {
+			adapter = androidExecutor.runOnBackgroundThread(
+					BluetoothAdapter::getDefaultAdapter).get();
+		} catch (InterruptedException | ExecutionException e) {
+			throw new IOException(e);
+		}
+		if (adapter == null)
+			throw new IOException("Bluetooth is not supported");
+	}
+
+	@Override
+	boolean isAdapterEnabled() {
+		return adapter != null && adapter.isEnabled();
+	}
+
+	@Override
+	@Nullable
+	String getBluetoothAddress() {
+		if (adapter == null) return null;
+		String address = AndroidUtils.getBluetoothAddress(app, adapter);
+		return address.isEmpty() ? null : address;
+	}
+
+	@Override
+	BluetoothServerSocket openServerSocket(String uuid) throws IOException {
+		return adapter.listenUsingInsecureRfcommWithServiceRecord(
+				"RFCOMM", UUID.fromString(uuid));
+	}
+
+	@Override
+	void tryToClose(@Nullable BluetoothServerSocket ss) {
+		IoUtils.tryToClose(ss, LOG, WARNING);
+	}
+
+	@Override
+	DuplexTransportConnection acceptConnection(BluetoothServerSocket ss)
+			throws IOException {
+		return connectionFactory.wrapSocket(this, ss.accept());
+	}
+
+	@Override
+	boolean isValidAddress(String address) {
+		return BluetoothAdapter.checkBluetoothAddress(address);
+	}
+
+	@Override
+	DuplexTransportConnection connectTo(String address, String uuid)
+			throws IOException {
+		BluetoothDevice d = adapter.getRemoteDevice(address);
+		UUID u = UUID.fromString(uuid);
+		BluetoothSocket s = null;
+		try {
+			s = d.createInsecureRfcommSocketToServiceRecord(u);
+			s.connect();
+			return connectionFactory.wrapSocket(this, s);
+		} catch (IOException e) {
+			IoUtils.tryToClose(s, LOG, WARNING);
+			throw e;
+		} catch (NullPointerException e) {
+			// BluetoothSocket#connect() may throw an NPE under unknown
+			// circumstances
+			IoUtils.tryToClose(s, LOG, WARNING);
+			throw new IOException(e);
+		}
+	}
+
+	@Override
+	@Nullable
+	DuplexTransportConnection discoverAndConnect(String uuid) {
+		if (adapter == null) return null;
+		if (!discoverSemaphore.tryAcquire()) {
+			LOG.info("Discover already running");
+			return null;
+		}
+		try {
+			stopDiscoverAndConnect = false;
+			for (String address : discoverDevices()) {
+				if (stopDiscoverAndConnect) {
+					break;
+				}
+				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));
+					}
+				}
+			}
+		} finally {
+			discoverSemaphore.release();
+		}
+		LOG.info("Could not connect to any devices");
+		return null;
+	}
+
+	@Override
+	public void stopDiscoverAndConnect() {
+		stopDiscoverAndConnect = true;
+		adapter.cancelDiscovery();
+	}
+
+	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);
+		app.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);
+						// Ignore Bluetooth LE devices
+						if (d.getType() != DEVICE_TYPE_LE) {
+							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();
+			app.unregisterReceiver(receiver);
+		}
+		// Shuffle the addresses so we don't always try the same one first
+		shuffle(addresses);
+		return addresses;
+	}
+
+	private class BluetoothStateReceiver extends BroadcastReceiver {
+
+		@Override
+		public void onReceive(Context ctx, Intent intent) {
+			int state = intent.getIntExtra(EXTRA_STATE, 0);
+			if (state == STATE_ON) onAdapterEnabled();
+			else if (state == STATE_OFF) onAdapterDisabled();
+			int scanMode = intent.getIntExtra(EXTRA_SCAN_MODE, 0);
+			if (scanMode == SCAN_MODE_NONE) {
+				LOG.info("Scan mode: None");
+			} else if (scanMode == SCAN_MODE_CONNECTABLE) {
+				LOG.info("Scan mode: Connectable");
+			} else if (scanMode == SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
+				LOG.info("Scan mode: Discoverable");
+			}
+		}
+	}
+
+	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);
+		}
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/plugin/bluetooth/AndroidBluetoothPluginFactory.java

@@ -0,0 +1,98 @@
+package org.briarproject.bramble.plugin.bluetooth;
+
+import android.app.Application;
+import android.bluetooth.BluetoothSocket;
+
+import org.briarproject.android.dontkillmelib.wakelock.AndroidWakeLockManager;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.io.TimeoutMonitor;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.plugin.Backoff;
+import org.briarproject.bramble.api.plugin.BackoffFactory;
+import org.briarproject.bramble.api.plugin.PluginCallback;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
+import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
+import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.system.WakefulIoExecutor;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.security.SecureRandom;
+import java.util.concurrent.Executor;
+
+import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
+
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
+
+@Immutable
+@NotNullByDefault
+public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
+
+	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
+	private static final int MAX_IDLE_TIME = 30 * 1000; // 30 seconds
+	private static final int MIN_POLLING_INTERVAL = 60 * 1000; // 1 minute
+	private static final int MAX_POLLING_INTERVAL = 10 * 60 * 1000; // 10 mins
+	private static final double BACKOFF_BASE = 1.2;
+
+	private final Executor ioExecutor, wakefulIoExecutor;
+	private final AndroidExecutor androidExecutor;
+	private final AndroidWakeLockManager wakeLockManager;
+	private final Application app;
+	private final SecureRandom secureRandom;
+	private final EventBus eventBus;
+	private final Clock clock;
+	private final TimeoutMonitor timeoutMonitor;
+	private final BackoffFactory backoffFactory;
+
+	@Inject
+	AndroidBluetoothPluginFactory(@IoExecutor Executor ioExecutor,
+			@WakefulIoExecutor Executor wakefulIoExecutor,
+			AndroidExecutor androidExecutor,
+			AndroidWakeLockManager wakeLockManager,
+			Application app,
+			SecureRandom secureRandom,
+			EventBus eventBus,
+			Clock clock,
+			TimeoutMonitor timeoutMonitor,
+			BackoffFactory backoffFactory) {
+		this.ioExecutor = ioExecutor;
+		this.wakefulIoExecutor = wakefulIoExecutor;
+		this.androidExecutor = androidExecutor;
+		this.wakeLockManager = wakeLockManager;
+		this.app = app;
+		this.secureRandom = secureRandom;
+		this.eventBus = eventBus;
+		this.clock = clock;
+		this.timeoutMonitor = timeoutMonitor;
+		this.backoffFactory = backoffFactory;
+	}
+
+	@Override
+	public TransportId getId() {
+		return ID;
+	}
+
+	@Override
+	public long getMaxLatency() {
+		return MAX_LATENCY;
+	}
+
+	@Override
+	public DuplexPlugin createPlugin(PluginCallback callback) {
+		BluetoothConnectionLimiter connectionLimiter =
+				new BluetoothConnectionLimiterImpl(eventBus);
+		BluetoothConnectionFactory<BluetoothSocket> connectionFactory =
+				new AndroidBluetoothConnectionFactory(connectionLimiter,
+						wakeLockManager, timeoutMonitor);
+		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
+				MAX_POLLING_INTERVAL, BACKOFF_BASE);
+		AndroidBluetoothPlugin plugin = new AndroidBluetoothPlugin(
+				connectionLimiter, connectionFactory, ioExecutor,
+				wakefulIoExecutor, secureRandom, androidExecutor, app,
+				clock, backoff, callback, MAX_LATENCY, MAX_IDLE_TIME);
+		eventBus.addListener(plugin);
+		return plugin;
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/plugin/bluetooth/AndroidBluetoothTransportConnection.java

@@ -0,0 +1,68 @@
+package org.briarproject.bramble.plugin.bluetooth;
+
+import android.bluetooth.BluetoothSocket;
+
+import org.briarproject.android.dontkillmelib.wakelock.AndroidWakeLock;
+import org.briarproject.android.dontkillmelib.wakelock.AndroidWakeLockManager;
+import org.briarproject.bramble.api.io.TimeoutMonitor;
+import org.briarproject.bramble.api.plugin.Plugin;
+import org.briarproject.bramble.api.plugin.duplex.AbstractDuplexTransportConnection;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_ADDRESS;
+import static org.briarproject.bramble.util.AndroidUtils.isValidBluetoothAddress;
+
+@NotNullByDefault
+class AndroidBluetoothTransportConnection
+		extends AbstractDuplexTransportConnection {
+
+	private final BluetoothConnectionLimiter connectionLimiter;
+	private final BluetoothSocket socket;
+	private final InputStream in;
+	private final AndroidWakeLock wakeLock;
+
+	AndroidBluetoothTransportConnection(Plugin plugin,
+			BluetoothConnectionLimiter connectionLimiter,
+			AndroidWakeLockManager wakeLockManager,
+			TimeoutMonitor timeoutMonitor,
+			BluetoothSocket socket) throws IOException {
+		super(plugin);
+		this.connectionLimiter = connectionLimiter;
+		this.socket = socket;
+		InputStream socketIn = socket.getInputStream();
+		if (socketIn == null) throw new IOException();
+		in = timeoutMonitor.createTimeoutInputStream(socketIn,
+				plugin.getMaxIdleTime() * 2L);
+		wakeLock = wakeLockManager.createWakeLock("BluetoothConnection");
+		wakeLock.acquire();
+		String address = socket.getRemoteDevice().getAddress();
+		if (isValidBluetoothAddress(address)) remote.put(PROP_ADDRESS, address);
+	}
+
+	@Override
+	protected InputStream getInputStream() {
+		return in;
+	}
+
+	@Override
+	protected OutputStream getOutputStream() throws IOException {
+		OutputStream socketOut = socket.getOutputStream();
+		if (socketOut == null) throw new IOException();
+		return socketOut;
+	}
+
+	@Override
+	protected void closeConnection(boolean exception) throws IOException {
+		try {
+			socket.close();
+			in.close();
+		} finally {
+			wakeLock.release();
+			connectionLimiter.connectionClosed(this);
+		}
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/plugin/file/AndroidRemovableDrivePlugin.java

@@ -0,0 +1,53 @@
+package org.briarproject.bramble.plugin.file;
+
+import android.app.Application;
+import android.net.Uri;
+
+import org.briarproject.bramble.api.plugin.PluginCallback;
+import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import javax.annotation.concurrent.Immutable;
+
+import static org.briarproject.bramble.api.plugin.file.RemovableDriveConstants.PROP_URI;
+import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
+
+@Immutable
+@NotNullByDefault
+class AndroidRemovableDrivePlugin extends RemovableDrivePlugin {
+
+	private final Application app;
+
+	AndroidRemovableDrivePlugin(Application app, PluginCallback callback,
+			long maxLatency) {
+		super(callback, maxLatency);
+		this.app = app;
+	}
+
+	@Override
+	InputStream openInputStream(TransportProperties p) throws IOException {
+		String uri = p.get(PROP_URI);
+		if (isNullOrEmpty(uri)) throw new IllegalArgumentException();
+		try {
+			return app.getContentResolver().openInputStream(Uri.parse(uri));
+		} catch (SecurityException e) {
+			throw new IOException(e);
+		}
+	}
+
+	@Override
+	OutputStream openOutputStream(TransportProperties p) throws IOException {
+		String uri = p.get(PROP_URI);
+		if (isNullOrEmpty(uri)) throw new IllegalArgumentException();
+		try {
+			return app.getContentResolver()
+					.openOutputStream(Uri.parse(uri), "wt");
+		} catch (SecurityException e) {
+			throw new IOException(e);
+		}
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/plugin/file/AndroidRemovableDrivePluginFactory.java

@@ -0,0 +1,47 @@
+package org.briarproject.bramble.plugin.file;
+
+import android.app.Application;
+
+import org.briarproject.bramble.api.plugin.PluginCallback;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
+import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
+
+import static java.util.concurrent.TimeUnit.DAYS;
+import static org.briarproject.bramble.api.plugin.file.RemovableDriveConstants.ID;
+
+@Immutable
+@NotNullByDefault
+public class AndroidRemovableDrivePluginFactory implements
+		SimplexPluginFactory {
+
+	private static final long MAX_LATENCY = DAYS.toMillis(28);
+
+	private final Application app;
+
+	@Inject
+	AndroidRemovableDrivePluginFactory(Application app) {
+		this.app = app;
+	}
+
+	@Override
+	public TransportId getId() {
+		return ID;
+	}
+
+	@Override
+	public long getMaxLatency() {
+		return MAX_LATENCY;
+	}
+
+	@Nullable
+	@Override
+	public SimplexPlugin createPlugin(PluginCallback callback) {
+		return new AndroidRemovableDrivePlugin(app, callback, MAX_LATENCY);
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/plugin/tcp/AndroidLanTcpPlugin.java

@@ -0,0 +1,307 @@
+package org.briarproject.bramble.plugin.tcp;
+
+import android.app.Application;
+import android.net.ConnectivityManager;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
+import android.net.Network;
+import android.net.NetworkCapabilities;
+import android.net.wifi.WifiInfo;
+import android.net.wifi.WifiManager;
+
+import org.briarproject.bramble.PoliteExecutor;
+import org.briarproject.bramble.api.Pair;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.network.event.NetworkStatusEvent;
+import org.briarproject.bramble.api.plugin.Backoff;
+import org.briarproject.bramble.api.plugin.PluginCallback;
+import org.briarproject.bramble.api.settings.Settings;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.InterfaceAddress;
+import java.net.NetworkInterface;
+import java.net.Socket;
+import java.net.SocketException;
+import java.net.UnknownHostException;
+import java.util.List;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+import java.util.regex.Pattern;
+
+import javax.annotation.Nullable;
+import javax.net.SocketFactory;
+
+import static android.content.Context.CONNECTIVITY_SERVICE;
+import static android.content.Context.WIFI_SERVICE;
+import static android.net.NetworkCapabilities.TRANSPORT_WIFI;
+import static java.util.Collections.emptyList;
+import static java.util.Collections.list;
+import static java.util.Collections.singletonList;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.plugin.LanTcpConstants.DEFAULT_PREF_PLUGIN_ENABLE;
+import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
+import static org.briarproject.bramble.api.plugin.Plugin.State.INACTIVE;
+import static org.briarproject.bramble.util.IoUtils.tryToClose;
+import static org.briarproject.bramble.util.LogUtils.logException;
+import static org.briarproject.bramble.util.NetworkUtils.getNetworkInterfaces;
+import static org.briarproject.nullsafety.NullSafety.requireNonNull;
+
+@NotNullByDefault
+class AndroidLanTcpPlugin extends LanTcpPlugin {
+
+	private static final Logger LOG =
+			getLogger(AndroidLanTcpPlugin.class.getName());
+
+	/**
+	 * The interface name is used as a heuristic for deciding whether the
+	 * device is providing a wifi access point.
+	 */
+	private static final Pattern AP_INTERFACE_NAME =
+			Pattern.compile("^(wlan|ap|p2p)[-0-9]");
+
+	private final Executor connectionStatusExecutor;
+	private final ConnectivityManager connectivityManager;
+	@Nullable
+	private final WifiManager wifiManager;
+
+	private volatile SocketFactory socketFactory;
+
+	AndroidLanTcpPlugin(Executor ioExecutor,
+			Executor wakefulIoExecutor,
+			Application app,
+			Backoff backoff,
+			PluginCallback callback,
+			long maxLatency,
+			int maxIdleTime,
+			int connectionTimeout) {
+		super(ioExecutor, wakefulIoExecutor, backoff, callback, maxLatency,
+				maxIdleTime, connectionTimeout);
+		// Don't execute more than one connection status check at a time
+		connectionStatusExecutor =
+				new PoliteExecutor("AndroidLanTcpPlugin", ioExecutor, 1);
+		connectivityManager = (ConnectivityManager)
+				requireNonNull(app.getSystemService(CONNECTIVITY_SERVICE));
+		wifiManager = (WifiManager) app.getSystemService(WIFI_SERVICE);
+		socketFactory = SocketFactory.getDefault();
+	}
+
+	@Override
+	public void start() {
+		if (used.getAndSet(true)) throw new IllegalStateException();
+		initialisePortProperty();
+		Settings settings = callback.getSettings();
+		state.setStarted(settings.getBoolean(PREF_PLUGIN_ENABLE,
+				DEFAULT_PREF_PLUGIN_ENABLE));
+		updateConnectionStatus();
+	}
+
+	@Override
+	protected Socket createSocket() throws IOException {
+		return socketFactory.createSocket();
+	}
+
+	@Override
+	protected List<InetAddress> getUsableLocalInetAddresses(boolean ipv4) {
+		InetAddress addr = getWifiAddress(ipv4);
+		return addr == null ? emptyList() : singletonList(addr);
+	}
+
+	@Nullable
+	private InetAddress getWifiAddress(boolean ipv4) {
+		Pair<InetAddress, Boolean> wifi = getWifiIpv4Address();
+		if (ipv4) return wifi == null ? null : wifi.getFirst();
+		// If there's no wifi IPv4 address, we might be a client on an
+		// IPv6-only wifi network. We can only detect this on API 21+
+		if (wifi == null) {
+			return getWifiClientIpv6Address();
+		}
+		// Use the wifi IPv4 address to determine which interface's IPv6
+		// address we should return (if the interface has a suitable address)
+		return getIpv6AddressForInterface(wifi.getFirst());
+	}
+
+	/**
+	 * Returns a {@link Pair} where the first element is the IPv4 address of
+	 * the wifi interface and the second element is true if this device is
+	 * providing an access point, or false if this device is a client. Returns
+	 * null if this device isn't connected to wifi as an access point or client.
+	 */
+	@Nullable
+	private Pair<InetAddress, Boolean> getWifiIpv4Address() {
+		if (wifiManager == null) return null;
+		// If we're connected to a wifi network, return its address
+		WifiInfo info = wifiManager.getConnectionInfo();
+		if (info != null && info.getIpAddress() != 0) {
+			return new Pair<>(intToInetAddress(info.getIpAddress()), false);
+		}
+		// If we're providing an access point, return its address
+		for (NetworkInterface iface : getNetworkInterfaces()) {
+			if (AP_INTERFACE_NAME.matcher(iface.getName()).find()) {
+				for (InterfaceAddress ifAddr : iface.getInterfaceAddresses()) {
+					if (isPossibleWifiApInterface(ifAddr)) {
+						return new Pair<>(ifAddr.getAddress(), true);
+					}
+				}
+			}
+		}
+		// Not connected to wifi
+		return null;
+	}
+
+	/**
+	 * Returns true if the given address may belong to an interface providing
+	 * a wifi access point (including wifi direct legacy mode access points).
+	 * <p>
+	 * This method may return true for wifi client interfaces as well, but
+	 * we've already checked for a wifi client connection above.
+	 */
+	private boolean isPossibleWifiApInterface(InterfaceAddress ifAddr) {
+		if (ifAddr.getNetworkPrefixLength() != 24) return false;
+		byte[] ip = ifAddr.getAddress().getAddress();
+		return ip.length == 4
+				&& ip[0] == (byte) 192
+				&& ip[1] == (byte) 168;
+	}
+
+	/**
+	 * Returns a link-local IPv6 address for the wifi client interface, or null
+	 * if there's no such interface or it doesn't have a suitable address.
+	 */
+	@Nullable
+	private InetAddress getWifiClientIpv6Address() {
+		// https://issuetracker.google.com/issues/175055271
+		try {
+			for (Network net : connectivityManager.getAllNetworks()) {
+				NetworkCapabilities caps =
+						connectivityManager.getNetworkCapabilities(net);
+				if (caps == null || !caps.hasTransport(TRANSPORT_WIFI)) {
+					continue;
+				}
+				LinkProperties props =
+						connectivityManager.getLinkProperties(net);
+				if (props == null) continue;
+				for (LinkAddress linkAddress : props.getLinkAddresses()) {
+					InetAddress addr = linkAddress.getAddress();
+					if (isIpv6LinkLocalAddress(addr)) return addr;
+				}
+			}
+		} catch (SecurityException e) {
+			logException(LOG, WARNING, e);
+		}
+		return null;
+	}
+
+	/**
+	 * Returns a link-local IPv6 address for the interface with the given IPv4
+	 * address, or null if the interface doesn't have a suitable address.
+	 */
+	@Nullable
+	private InetAddress getIpv6AddressForInterface(InetAddress ipv4) {
+		try {
+			NetworkInterface iface = NetworkInterface.getByInetAddress(ipv4);
+			if (iface == null) return null;
+			for (InetAddress addr : list(iface.getInetAddresses())) {
+				if (isIpv6LinkLocalAddress(addr)) return addr;
+			}
+			// No suitable address
+			return null;
+		} catch (SocketException e) {
+			logException(LOG, WARNING, e);
+			return null;
+		}
+	}
+
+	private InetAddress intToInetAddress(int ip) {
+		byte[] ipBytes = new byte[4];
+		ipBytes[0] = (byte) (ip & 0xFF);
+		ipBytes[1] = (byte) ((ip >> 8) & 0xFF);
+		ipBytes[2] = (byte) ((ip >> 16) & 0xFF);
+		ipBytes[3] = (byte) ((ip >> 24) & 0xFF);
+		try {
+			return InetAddress.getByAddress(ipBytes);
+		} catch (UnknownHostException e) {
+			// Should only be thrown if address has illegal length
+			throw new AssertionError(e);
+		}
+	}
+
+	// On API 21 and later, a socket that is not created with the wifi
+	// network's socket factory may try to connect via another network
+	private SocketFactory getSocketFactory() {
+		// https://issuetracker.google.com/issues/175055271
+		try {
+			for (Network net : connectivityManager.getAllNetworks()) {
+				NetworkCapabilities caps =
+						connectivityManager.getNetworkCapabilities(net);
+				if (caps != null && caps.hasTransport(TRANSPORT_WIFI)) {
+					return net.getSocketFactory();
+				}
+			}
+		} catch (SecurityException e) {
+			logException(LOG, WARNING, e);
+		}
+		LOG.warning("Could not find suitable socket factory");
+		return SocketFactory.getDefault();
+	}
+
+	@Override
+	public void eventOccurred(Event e) {
+		super.eventOccurred(e);
+		if (e instanceof NetworkStatusEvent) updateConnectionStatus();
+	}
+
+	private void updateConnectionStatus() {
+		connectionStatusExecutor.execute(() -> {
+			State s = getState();
+			if (s != ACTIVE && s != INACTIVE) return;
+			Pair<InetAddress, Boolean> wifi = getPreferredWifiAddress();
+			if (wifi == null) {
+				LOG.info("Not connected to wifi");
+				socketFactory = SocketFactory.getDefault();
+				// Server sockets may not have been closed automatically when
+				// interface was taken down. If any sockets are open, closing
+				// them here will cause the sockets to be cleared and the state
+				// to be updated in acceptContactConnections()
+				if (s == ACTIVE) {
+					LOG.info("Closing server sockets");
+					tryToClose(state.getServerSocket(true), LOG, WARNING);
+					tryToClose(state.getServerSocket(false), LOG, WARNING);
+				}
+			} else if (wifi.getSecond()) {
+				LOG.info("Providing wifi hotspot");
+				// There's no corresponding Network object and thus no way
+				// to get a suitable socket factory, so we won't be able to
+				// make outgoing connections on API 21+ if another network
+				// has internet access
+				socketFactory = SocketFactory.getDefault();
+				bind();
+			} else {
+				LOG.info("Connected to wifi");
+				socketFactory = getSocketFactory();
+				bind();
+			}
+		});
+	}
+
+	/**
+	 * Returns a {@link Pair} where the first element is an IP address (IPv4 if
+	 * available, otherwise IPv6) of the wifi interface and the second element
+	 * is true if this device is providing an access point, or false if this
+	 * device is a client. Returns null if this device isn't connected to wifi
+	 * as an access point or client.
+	 */
+	@Nullable
+	private Pair<InetAddress, Boolean> getPreferredWifiAddress() {
+		Pair<InetAddress, Boolean> wifi = getWifiIpv4Address();
+		// If there's no wifi IPv4 address, we might be a client on an
+		// IPv6-only wifi network. We can only detect this on API 21+
+		if (wifi == null) {
+			InetAddress ipv6 = getWifiClientIpv6Address();
+			if (ipv6 != null) return new Pair<>(ipv6, false);
+		}
+		return wifi;
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/plugin/tcp/AndroidLanTcpPluginFactory.java

@@ -0,0 +1,72 @@
+package org.briarproject.bramble.plugin.tcp;
+
+import android.app.Application;
+
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.plugin.Backoff;
+import org.briarproject.bramble.api.plugin.BackoffFactory;
+import org.briarproject.bramble.api.plugin.PluginCallback;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
+import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
+import org.briarproject.bramble.api.system.WakefulIoExecutor;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.util.concurrent.Executor;
+
+import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
+
+import static org.briarproject.bramble.api.plugin.LanTcpConstants.ID;
+
+@Immutable
+@NotNullByDefault
+public class AndroidLanTcpPluginFactory implements DuplexPluginFactory {
+
+	private static final int MAX_LATENCY = 30_000; // 30 seconds
+	private static final int MAX_IDLE_TIME = 30_000; // 30 seconds
+	private static final int CONNECTION_TIMEOUT = 3_000; // 3 seconds
+	private static final int MIN_POLLING_INTERVAL = 60_000; // 1 minute
+	private static final int MAX_POLLING_INTERVAL = 600_000; // 10 mins
+	private static final double BACKOFF_BASE = 1.2;
+
+	private final Executor ioExecutor, wakefulIoExecutor;
+	private final EventBus eventBus;
+	private final BackoffFactory backoffFactory;
+	private final Application app;
+
+	@Inject
+	AndroidLanTcpPluginFactory(@IoExecutor Executor ioExecutor,
+			@WakefulIoExecutor Executor wakefulIoExecutor,
+			EventBus eventBus,
+			BackoffFactory backoffFactory,
+			Application app) {
+		this.ioExecutor = ioExecutor;
+		this.wakefulIoExecutor = wakefulIoExecutor;
+		this.eventBus = eventBus;
+		this.backoffFactory = backoffFactory;
+		this.app = app;
+	}
+
+	@Override
+	public TransportId getId() {
+		return ID;
+	}
+
+	@Override
+	public long getMaxLatency() {
+		return MAX_LATENCY;
+	}
+
+	@Override
+	public DuplexPlugin createPlugin(PluginCallback callback) {
+		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
+				MAX_POLLING_INTERVAL, BACKOFF_BASE);
+		AndroidLanTcpPlugin plugin = new AndroidLanTcpPlugin(ioExecutor,
+				wakefulIoExecutor, app, backoff, callback,
+				MAX_LATENCY, MAX_IDLE_TIME, CONNECTION_TIMEOUT);
+		eventBus.addListener(plugin);
+		return plugin;
+	}
+}

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

@@ -0,0 +1,100 @@
+package org.briarproject.bramble.plugin.tor;
+
+import android.app.Application;
+
+import org.briarproject.android.dontkillmelib.wakelock.AndroidWakeLockManager;
+import org.briarproject.bramble.api.battery.BatteryManager;
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventExecutor;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.network.NetworkManager;
+import org.briarproject.bramble.api.plugin.Backoff;
+import org.briarproject.bramble.api.plugin.BackoffFactory;
+import org.briarproject.bramble.api.plugin.PluginCallback;
+import org.briarproject.bramble.api.plugin.TorControlPort;
+import org.briarproject.bramble.api.plugin.TorDirectory;
+import org.briarproject.bramble.api.plugin.TorSocksPort;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.system.WakefulIoExecutor;
+import org.briarproject.nullsafety.NotNullByDefault;
+import org.briarproject.onionwrapper.AndroidTorWrapper;
+import org.briarproject.onionwrapper.CircumventionProvider;
+import org.briarproject.onionwrapper.LocationUtils;
+import org.briarproject.onionwrapper.TorWrapper;
+
+import java.io.File;
+import java.util.concurrent.Executor;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
+import javax.net.SocketFactory;
+
+import static android.os.Build.VERSION.SDK_INT;
+import static org.briarproject.bramble.util.AndroidUtils.getSupportedArchitectures;
+
+@Immutable
+@NotNullByDefault
+public class AndroidTorPluginFactory extends TorPluginFactory {
+
+	private final Application app;
+	private final AndroidWakeLockManager wakeLockManager;
+
+	@Inject
+	AndroidTorPluginFactory(@IoExecutor Executor ioExecutor,
+			@EventExecutor Executor eventExecutor,
+			@WakefulIoExecutor Executor wakefulIoExecutor,
+			NetworkManager networkManager,
+			LocationUtils locationUtils,
+			EventBus eventBus,
+			SocketFactory torSocketFactory,
+			BackoffFactory backoffFactory,
+			CircumventionProvider circumventionProvider,
+			BatteryManager batteryManager,
+			Clock clock,
+			CryptoComponent crypto,
+			@TorDirectory File torDirectory,
+			@TorSocksPort int torSocksPort,
+			@TorControlPort int torControlPort,
+			Application app,
+			AndroidWakeLockManager wakeLockManager) {
+		super(ioExecutor, eventExecutor, wakefulIoExecutor, networkManager,
+				locationUtils, eventBus, torSocketFactory, backoffFactory,
+				circumventionProvider, batteryManager, clock, crypto,
+				torDirectory, torSocksPort, torControlPort);
+		this.app = app;
+		this.wakeLockManager = wakeLockManager;
+	}
+
+	@Nullable
+	@Override
+	String getArchitectureForTorBinary() {
+		for (String abi : getSupportedArchitectures()) {
+			if (abi.startsWith("x86_64")) return "x86_64_pie";
+			else if (abi.startsWith("x86")) return "x86_pie";
+			else if (abi.startsWith("arm64")) return "arm64_pie";
+			else if (abi.startsWith("armeabi")) return "arm_pie";
+		}
+		return null;
+	}
+
+	@Override
+	TorPlugin createPluginInstance(Backoff backoff,
+			TorRendezvousCrypto torRendezvousCrypto, PluginCallback callback,
+			String architecture) {
+		TorWrapper tor = new AndroidTorWrapper(app, wakeLockManager,
+				ioExecutor, eventExecutor, architecture, torDirectory,
+				torSocksPort, torControlPort);
+		// Android versions 7.1 and newer can verify Let's Encrypt TLS certs
+		// signed with the IdentTrust DST Root X3 certificate. Older versions
+		// of Android consider the certificate to have expired at the end of
+		// September 2021.
+		boolean canVerifyLetsEncryptCerts = SDK_INT >= 25;
+		return new TorPlugin(ioExecutor, wakefulIoExecutor,
+				networkManager, locationUtils, torSocketFactory,
+				circumventionProvider, batteryManager, backoff,
+				torRendezvousCrypto, tor, callback, MAX_LATENCY,
+				MAX_IDLE_TIME, canVerifyLetsEncryptCerts);
+	}
+}

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

@@ -0,0 +1,18 @@
+package org.briarproject.bramble.system;
+
+import org.briarproject.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+interface AlarmConstants {
+
+	/**
+	 * Request code for the broadcast intent attached to the periodic alarm.
+	 */
+	int REQUEST_ALARM = 1;
+
+	/**
+	 * Key for storing the process ID in the extras of the periodic alarm's
+	 * intent. This allows us to ignore alarms scheduled by dead processes.
+	 */
+	String EXTRA_PID = "org.briarproject.bramble.EXTRA_PID";
+}

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

@@ -0,0 +1,17 @@
+package org.briarproject.bramble.system;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+
+import org.briarproject.bramble.BrambleApplication;
+
+public class AlarmReceiver extends BroadcastReceiver {
+
+	@Override
+	public void onReceive(Context ctx, Intent intent) {
+		BrambleApplication app =
+				(BrambleApplication) ctx.getApplicationContext();
+		app.getBrambleAppComponent().alarmListener().onAlarm(intent);
+	}
+}

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

@@ -0,0 +1,75 @@
+package org.briarproject.bramble.system;
+
+import android.app.Application;
+import android.os.Handler;
+import android.os.Looper;
+
+import org.briarproject.bramble.api.system.AndroidExecutor;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Future;
+import java.util.concurrent.FutureTask;
+import java.util.concurrent.RejectedExecutionException;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import javax.inject.Inject;
+
+class AndroidExecutorImpl implements AndroidExecutor {
+
+	private final Handler uiHandler;
+	private final Runnable loop;
+	private final AtomicBoolean started = new AtomicBoolean(false);
+	private final CountDownLatch startLatch = new CountDownLatch(1);
+
+	private volatile Handler backgroundHandler = null;
+
+	@Inject
+	AndroidExecutorImpl(Application app) {
+		uiHandler = new Handler(app.getApplicationContext().getMainLooper());
+		loop = () -> {
+			Looper.prepare();
+			backgroundHandler = new Handler();
+			startLatch.countDown();
+			Looper.loop();
+		};
+	}
+
+	private void startIfNecessary() {
+		if (!started.getAndSet(true)) {
+			Thread t = new Thread(loop, "AndroidExecutor");
+			t.setDaemon(true);
+			t.start();
+		}
+		try {
+			startLatch.await();
+		} catch (InterruptedException e) {
+			throw new RejectedExecutionException(e);
+		}
+	}
+
+	@Override
+	public <V> Future<V> runOnBackgroundThread(Callable<V> c) {
+		FutureTask<V> f = new FutureTask<>(c);
+		runOnBackgroundThread(f);
+		return f;
+	}
+
+	@Override
+	public void runOnBackgroundThread(Runnable r) {
+		startIfNecessary();
+		backgroundHandler.post(r);
+	}
+
+	@Override
+	public <V> Future<V> runOnUiThread(Callable<V> c) {
+		FutureTask<V> f = new FutureTask<>(c);
+		runOnUiThread(f);
+		return f;
+	}
+
+	@Override
+	public void runOnUiThread(Runnable r) {
+		uiHandler.post(r);
+	}
+}

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

@@ -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.system.ResourceProvider;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+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);
+	}
+}

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

@@ -0,0 +1,75 @@
+package org.briarproject.bramble.system;
+
+import android.annotation.SuppressLint;
+import android.app.Application;
+import android.bluetooth.BluetoothAdapter;
+import android.bluetooth.BluetoothDevice;
+import android.content.ContentResolver;
+import android.content.Context;
+import android.os.Parcel;
+import android.os.StrictMode;
+import android.provider.Settings;
+
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.util.Set;
+
+import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
+
+import static android.os.Build.FINGERPRINT;
+import static android.os.Build.SERIAL;
+import static android.os.Build.VERSION.SDK_INT;
+import static android.os.Process.myPid;
+import static android.os.Process.myTid;
+import static android.os.Process.myUid;
+import static android.provider.Settings.Secure.ANDROID_ID;
+
+@Immutable
+@NotNullByDefault
+class AndroidSecureRandomProvider extends UnixSecureRandomProvider {
+
+	private final Context appContext;
+
+	@Inject
+	AndroidSecureRandomProvider(Application app) {
+		appContext = app.getApplicationContext();
+	}
+
+	@SuppressLint("HardwareIds")
+	@Override
+	protected void writeToEntropyPool(DataOutputStream out) throws IOException {
+		super.writeToEntropyPool(out);
+		out.writeInt(myPid());
+		out.writeInt(myTid());
+		out.writeInt(myUid());
+		if (FINGERPRINT != null) out.writeUTF(FINGERPRINT);
+		if (SERIAL != null) out.writeUTF(SERIAL);
+		ContentResolver contentResolver = appContext.getContentResolver();
+		String id = Settings.Secure.getString(contentResolver, ANDROID_ID);
+		if (id != null) out.writeUTF(id);
+		// On API 31 and higher we need permission to access bonded devices
+		if (SDK_INT < 31) {
+			Parcel parcel = Parcel.obtain();
+			BluetoothAdapter bt = BluetoothAdapter.getDefaultAdapter();
+			if (bt != null) {
+				@SuppressLint("MissingPermission")
+				Set<BluetoothDevice> deviceSet = bt.getBondedDevices();
+				for (BluetoothDevice device : deviceSet)
+					parcel.writeParcelable(device, 0);
+			}
+			out.write(parcel.marshall());
+			parcel.recycle();
+		}
+	}
+
+	@Override
+	protected void writeSeed() {
+		// Silence strict mode
+		StrictMode.ThreadPolicy tp = StrictMode.allowThreadDiskWrites();
+		super.writeSeed();
+		StrictMode.setThreadPolicy(tp);
+	}
+}

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

@@ -0,0 +1,75 @@
+package org.briarproject.bramble.system;
+
+import android.app.Application;
+
+import org.briarproject.bramble.api.event.EventExecutor;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.bramble.api.system.ResourceProvider;
+import org.briarproject.bramble.api.system.SecureRandomProvider;
+import org.briarproject.onionwrapper.AndroidLocationUtilsFactory;
+import org.briarproject.onionwrapper.LocationUtils;
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.RejectedExecutionHandler;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
+
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class AndroidSystemModule {
+
+	private final ScheduledExecutorService scheduledExecutorService;
+
+	public AndroidSystemModule() {
+		// Discard tasks that are submitted during shutdown
+		RejectedExecutionHandler policy =
+				new ScheduledThreadPoolExecutor.DiscardPolicy();
+		scheduledExecutorService = new ScheduledThreadPoolExecutor(1, policy);
+	}
+
+	@Provides
+	@Singleton
+	ScheduledExecutorService provideScheduledExecutorService(
+			LifecycleManager lifecycleManager) {
+		lifecycleManager.registerForShutdown(scheduledExecutorService);
+		return scheduledExecutorService;
+	}
+
+	@Provides
+	@Singleton
+	SecureRandomProvider provideSecureRandomProvider(
+			AndroidSecureRandomProvider provider) {
+		return provider;
+	}
+
+	@Provides
+	@Singleton
+	LocationUtils provideLocationUtils(Application app) {
+		return AndroidLocationUtilsFactory.createAndroidLocationUtils(app);
+	}
+
+	@Provides
+	@Singleton
+	AndroidExecutor provideAndroidExecutor(
+			AndroidExecutorImpl androidExecutor) {
+		return androidExecutor;
+	}
+
+	@Provides
+	@Singleton
+	@EventExecutor
+	Executor provideEventExecutor(AndroidExecutor androidExecutor) {
+		return androidExecutor::runOnUiThread;
+	}
+
+	@Provides
+	@Singleton
+	ResourceProvider provideResourceProvider(AndroidResourceProvider provider) {
+		return provider;
+	}
+}

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

@@ -0,0 +1,247 @@
+package org.briarproject.bramble.system;
+
+import android.annotation.TargetApi;
+import android.app.AlarmManager;
+import android.app.Application;
+import android.app.PendingIntent;
+import android.content.Intent;
+import android.os.Process;
+import android.os.SystemClock;
+
+import org.briarproject.android.dontkillmelib.wakelock.AndroidWakeLockManager;
+import org.briarproject.bramble.api.Cancellable;
+import org.briarproject.bramble.api.lifecycle.Service;
+import org.briarproject.bramble.api.system.AlarmListener;
+import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.api.system.Wakeful;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.PriorityQueue;
+import java.util.Queue;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Future;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.logging.Logger;
+
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+
+import static android.app.AlarmManager.ELAPSED_REALTIME_WAKEUP;
+import static android.app.AlarmManager.INTERVAL_FIFTEEN_MINUTES;
+import static android.app.PendingIntent.FLAG_CANCEL_CURRENT;
+import static android.content.Context.ALARM_SERVICE;
+import static android.os.Build.VERSION.SDK_INT;
+import static java.util.Objects.requireNonNull;
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.system.AlarmConstants.EXTRA_PID;
+import static org.briarproject.bramble.system.AlarmConstants.REQUEST_ALARM;
+import static org.briarproject.bramble.util.AndroidUtils.getImmutableFlags;
+
+@ThreadSafe
+@NotNullByDefault
+class AndroidTaskScheduler implements TaskScheduler, Service, AlarmListener {
+
+	private static final Logger LOG =
+			getLogger(AndroidTaskScheduler.class.getName());
+
+	private static final long ALARM_MS = INTERVAL_FIFTEEN_MINUTES;
+
+	private final Application app;
+	private final AndroidWakeLockManager wakeLockManager;
+	private final ScheduledExecutorService scheduledExecutorService;
+	private final AlarmManager alarmManager;
+
+	private final Object lock = new Object();
+	@GuardedBy("lock")
+	private final Queue<ScheduledTask> tasks = new PriorityQueue<>();
+
+	AndroidTaskScheduler(Application app,
+			AndroidWakeLockManager wakeLockManager,
+			ScheduledExecutorService scheduledExecutorService) {
+		this.app = app;
+		this.wakeLockManager = wakeLockManager;
+		this.scheduledExecutorService = scheduledExecutorService;
+		alarmManager = (AlarmManager)
+				requireNonNull(app.getSystemService(ALARM_SERVICE));
+	}
+
+	@Override
+	public void startService() {
+		scheduleAlarm();
+	}
+
+	@Override
+	public void stopService() {
+		cancelAlarm();
+	}
+
+	@Override
+	public Cancellable schedule(Runnable task, Executor executor, long delay,
+			TimeUnit unit) {
+		AtomicBoolean cancelled = new AtomicBoolean(false);
+		return schedule(task, executor, delay, unit, cancelled);
+	}
+
+	@Override
+	public Cancellable scheduleWithFixedDelay(Runnable task, Executor executor,
+			long delay, long interval, TimeUnit unit) {
+		AtomicBoolean cancelled = new AtomicBoolean(false);
+		return scheduleWithFixedDelay(task, executor, delay, interval, unit,
+				cancelled);
+	}
+
+	@Override
+	public void onAlarm(Intent intent) {
+		wakeLockManager.runWakefully(() -> {
+			int extraPid = intent.getIntExtra(EXTRA_PID, -1);
+			int currentPid = Process.myPid();
+			if (extraPid == currentPid) {
+				LOG.info("Alarm");
+				rescheduleAlarm();
+				runDueTasks();
+			} else if (LOG.isLoggable(INFO)) {
+				LOG.info("Ignoring alarm with PID " + extraPid
+						+ ", current PID is " + currentPid);
+			}
+		}, "TaskAlarm");
+	}
+
+	private Cancellable schedule(Runnable task, Executor executor, long delay,
+			TimeUnit unit, AtomicBoolean cancelled) {
+		long now = SystemClock.elapsedRealtime();
+		long dueMillis = now + MILLISECONDS.convert(delay, unit);
+		Runnable wakeful = () ->
+				wakeLockManager.executeWakefully(task, executor, "TaskHandoff");
+		// Acquire the lock before scheduling the check to ensure the check
+		// doesn't access the task queue before the task has been added
+		ScheduledTask s;
+		synchronized (lock) {
+			Future<?> check = scheduleCheckForDueTasks(delay, unit);
+			s = new ScheduledTask(wakeful, dueMillis, check, cancelled);
+			tasks.add(s);
+		}
+		return s;
+	}
+
+	private Cancellable scheduleWithFixedDelay(Runnable task, Executor executor,
+			long delay, long interval, TimeUnit unit, AtomicBoolean cancelled) {
+		// All executions of this periodic task share a cancelled flag
+		Runnable wrapped = () -> {
+			task.run();
+			scheduleWithFixedDelay(task, executor, interval, interval, unit,
+					cancelled);
+		};
+		return schedule(wrapped, executor, delay, unit, cancelled);
+	}
+
+	@GuardedBy("lock")
+	private Future<?> scheduleCheckForDueTasks(long delay, TimeUnit unit) {
+		Runnable wakeful = () -> wakeLockManager.runWakefully(
+				this::runDueTasks, "TaskScheduler");
+		return scheduledExecutorService.schedule(wakeful, delay, unit);
+	}
+
+	@Wakeful
+	private void runDueTasks() {
+		long now = SystemClock.elapsedRealtime();
+		List<ScheduledTask> due = new ArrayList<>();
+		synchronized (lock) {
+			while (true) {
+				ScheduledTask s = tasks.peek();
+				if (s == null || s.dueMillis > now) break;
+				due.add(tasks.remove());
+			}
+		}
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Running " + due.size() + " due tasks");
+		}
+		for (ScheduledTask s : due) {
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Task is " + (now - s.dueMillis) + " ms overdue");
+			}
+			s.run();
+		}
+	}
+
+	private void scheduleAlarm() {
+		if (SDK_INT >= 23) scheduleIdleAlarm();
+		else scheduleInexactRepeatingAlarm();
+	}
+
+	private void rescheduleAlarm() {
+		// If SDK_INT < 23 the alarm repeats automatically
+		if (SDK_INT >= 23) scheduleIdleAlarm();
+	}
+
+	private void cancelAlarm() {
+		alarmManager.cancel(getAlarmPendingIntent());
+	}
+
+	private void scheduleInexactRepeatingAlarm() {
+		alarmManager.setInexactRepeating(ELAPSED_REALTIME_WAKEUP,
+				SystemClock.elapsedRealtime() + ALARM_MS, ALARM_MS,
+				getAlarmPendingIntent());
+	}
+
+	@TargetApi(23)
+	private void scheduleIdleAlarm() {
+		alarmManager.setAndAllowWhileIdle(ELAPSED_REALTIME_WAKEUP,
+				SystemClock.elapsedRealtime() + ALARM_MS,
+				getAlarmPendingIntent());
+	}
+
+	private PendingIntent getAlarmPendingIntent() {
+		Intent i = new Intent(app, AlarmReceiver.class);
+		i.putExtra(EXTRA_PID, android.os.Process.myPid());
+		return PendingIntent.getBroadcast(app, REQUEST_ALARM, i,
+				getImmutableFlags(FLAG_CANCEL_CURRENT));
+	}
+
+	private class ScheduledTask
+			implements Runnable, Cancellable, Comparable<ScheduledTask> {
+
+		private final Runnable task;
+		private final long dueMillis;
+		private final Future<?> check;
+		private final AtomicBoolean cancelled;
+
+		private ScheduledTask(Runnable task, long dueMillis,
+				Future<?> check, AtomicBoolean cancelled) {
+			this.task = task;
+			this.dueMillis = dueMillis;
+			this.check = check;
+			this.cancelled = cancelled;
+		}
+
+		@Override
+		public void run() {
+			if (!cancelled.get()) task.run();
+		}
+
+		@Override
+		public void cancel() {
+			// Cancel any future executions of this task
+			cancelled.set(true);
+			// Cancel the scheduled check for due tasks
+			check.cancel(false);
+			// Remove the task from the queue
+			synchronized (lock) {
+				tasks.remove(this);
+			}
+		}
+
+		@Override
+		public int compareTo(ScheduledTask s) {
+			//noinspection UseCompareMethod
+			if (dueMillis < s.dueMillis) return -1;
+			if (dueMillis > s.dueMillis) return 1;
+			return 0;
+		}
+	}
+}

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

@@ -0,0 +1,49 @@
+package org.briarproject.bramble.system;
+
+import android.app.Application;
+
+import org.briarproject.android.dontkillmelib.wakelock.AndroidWakeLockManager;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.system.AlarmListener;
+import org.briarproject.bramble.api.system.TaskScheduler;
+
+import java.util.concurrent.ScheduledExecutorService;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class AndroidTaskSchedulerModule {
+
+	public static class EagerSingletons {
+		@Inject
+		AndroidTaskScheduler scheduler;
+	}
+
+	@Provides
+	@Singleton
+	AndroidTaskScheduler provideAndroidTaskScheduler(
+			LifecycleManager lifecycleManager, Application app,
+			AndroidWakeLockManager wakeLockManager,
+			ScheduledExecutorService scheduledExecutorService) {
+		AndroidTaskScheduler scheduler = new AndroidTaskScheduler(app,
+				wakeLockManager, scheduledExecutorService);
+		lifecycleManager.registerService(scheduler);
+		return scheduler;
+	}
+
+	@Provides
+	@Singleton
+	AlarmListener provideAlarmListener(AndroidTaskScheduler scheduler) {
+		return scheduler;
+	}
+
+	@Provides
+	@Singleton
+	TaskScheduler provideTaskScheduler(AndroidTaskScheduler scheduler) {
+		return scheduler;
+	}
+}

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

@@ -0,0 +1,25 @@
+package org.briarproject.bramble.system;
+
+import android.app.Application;
+
+import org.briarproject.android.dontkillmelib.wakelock.AndroidWakeLockManager;
+import org.briarproject.android.dontkillmelib.wakelock.AndroidWakeLockManagerFactory;
+
+import java.util.concurrent.ScheduledExecutorService;
+
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class AndroidWakeLockModule {
+
+	@Provides
+	@Singleton
+	AndroidWakeLockManager provideWakeLockManager(Application app,
+			ScheduledExecutorService scheduledExecutorService) {
+		return AndroidWakeLockManagerFactory.createAndroidWakeLockManager(app,
+				scheduledExecutorService);
+	}
+}

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

@@ -0,0 +1,23 @@
+package org.briarproject.bramble.system;
+
+import org.briarproject.android.dontkillmelib.wakelock.AndroidWakeLockManager;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.system.WakefulIoExecutor;
+
+import java.util.concurrent.Executor;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public
+class AndroidWakefulIoExecutorModule {
+
+	@Provides
+	@WakefulIoExecutor
+	Executor provideWakefulIoExecutor(@IoExecutor Executor ioExecutor,
+			AndroidWakeLockManager wakeLockManager) {
+		return r -> wakeLockManager.executeWakefully(r, ioExecutor,
+				"WakefulIoExecutor");
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/util/AndroidUtils.java

@@ -0,0 +1,139 @@
+package org.briarproject.bramble.util;
+
+import android.annotation.SuppressLint;
+import android.bluetooth.BluetoothAdapter;
+import android.content.Context;
+import android.os.Build;
+import android.os.Looper;
+import android.provider.Settings;
+
+import org.briarproject.bramble.api.Pair;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.io.File;
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.Collection;
+
+import javax.annotation.Nullable;
+
+import static android.Manifest.permission.BLUETOOTH_CONNECT;
+import static android.app.PendingIntent.FLAG_IMMUTABLE;
+import static android.content.Context.MODE_PRIVATE;
+import static android.content.pm.PackageManager.PERMISSION_GRANTED;
+import static android.os.Build.VERSION.SDK_INT;
+import static android.os.Process.myPid;
+import static android.os.Process.myUid;
+import static java.util.Arrays.asList;
+import static org.briarproject.nullsafety.NullSafety.requireNonNull;
+
+@NotNullByDefault
+public class AndroidUtils {
+
+	// Fake Bluetooth address returned by BluetoothAdapter on API 23 and later
+	private static final String FAKE_BLUETOOTH_ADDRESS = "02:00:00:00:00:00";
+
+	private static final String STORED_REPORTS = "dev-reports";
+	private static final String STORED_LOGCAT = "dev-logcat";
+
+	public static Collection<String> getSupportedArchitectures() {
+		return asList(Build.SUPPORTED_ABIS);
+	}
+
+	public static boolean hasBtConnectPermission(Context ctx) {
+		return SDK_INT < 31 || ctx.checkPermission(BLUETOOTH_CONNECT, myPid(),
+				myUid()) == PERMISSION_GRANTED;
+	}
+
+	public static String getBluetoothAddress(Context ctx,
+			BluetoothAdapter adapter) {
+		return getBluetoothAddressAndMethod(ctx, adapter).getFirst();
+	}
+
+	public static Pair<String, String> getBluetoothAddressAndMethod(Context ctx,
+			BluetoothAdapter adapter) {
+		// If we don't have permission to access the adapter's address, let
+		// the caller know we can't find it
+		if (!hasBtConnectPermission(ctx)) return new Pair<>("", "");
+		// Return the adapter's address if it's valid and not fake
+		@SuppressLint("HardwareIds")
+		String address = adapter.getAddress();
+		if (isValidBluetoothAddress(address)) {
+			return new Pair<>(address, "adapter");
+		}
+		// Return the address from settings if it's valid and not fake
+		if (SDK_INT < 33) {
+			address = Settings.Secure.getString(ctx.getContentResolver(),
+					"bluetooth_address");
+			if (isValidBluetoothAddress(address)) {
+				return new Pair<>(address, "settings");
+			}
+		}
+		// Try to get the address via reflection
+		address = getBluetoothAddressByReflection(adapter);
+		if (isValidBluetoothAddress(address)) {
+			return new Pair<>(requireNonNull(address), "reflection");
+		}
+		// Let the caller know we can't find the address
+		return new Pair<>("", "");
+	}
+
+	public static boolean isValidBluetoothAddress(@Nullable String address) {
+		return !StringUtils.isNullOrEmpty(address)
+				&& BluetoothAdapter.checkBluetoothAddress(address)
+				&& !address.equals(FAKE_BLUETOOTH_ADDRESS);
+	}
+
+	@Nullable
+	private static String getBluetoothAddressByReflection(
+			BluetoothAdapter adapter) {
+		try {
+			Field mServiceField =
+					adapter.getClass().getDeclaredField("mService");
+			mServiceField.setAccessible(true);
+			Object mService = mServiceField.get(adapter);
+			// mService may be null when Bluetooth is disabled
+			if (mService == null) throw new NoSuchFieldException();
+			Method getAddressMethod =
+					mService.getClass().getMethod("getAddress");
+			return (String) getAddressMethod.invoke(mService);
+		} catch (NoSuchFieldException e) {
+			return null;
+		} catch (IllegalAccessException e) {
+			return null;
+		} catch (NoSuchMethodException e) {
+			return null;
+		} catch (InvocationTargetException e) {
+			return null;
+		} catch (SecurityException e) {
+			return null;
+		}
+	}
+
+	public static File getReportDir(Context ctx) {
+		return ctx.getDir(STORED_REPORTS, MODE_PRIVATE);
+	}
+
+	public static File getLogcatFile(Context ctx) {
+		return new File(ctx.getFilesDir(), STORED_LOGCAT);
+	}
+
+	/**
+	 * Returns an array of supported content types for image attachments.
+	 */
+	public static String[] getSupportedImageContentTypes() {
+		return new String[] {"image/jpeg", "image/png", "image/gif"};
+	}
+
+	public static boolean isUiThread() {
+		return Looper.myLooper() == Looper.getMainLooper();
+	}
+
+	public static int getImmutableFlags(int flags) {
+		if (SDK_INT >= 23) {
+			return FLAG_IMMUTABLE | flags;
+		}
+		return flags;
+	}
+}

bramble-android/src/main/res/values/strings.xml

@@ -0,0 +1,3 @@
+<resources>
+	<string name="app_name">Bramble</string>
+</resources>

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

@@ -0,0 +1,169 @@
+package org.briarproject.bramble.account;
+
+import android.app.Application;
+import android.content.SharedPreferences;
+import android.content.pm.ApplicationInfo;
+
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.db.DatabaseConfig;
+import org.briarproject.bramble.api.identity.IdentityManager;
+import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.jmock.Expectations;
+import org.jmock.imposters.ByteBuddyClassImposteriser;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.File;
+
+import static junit.framework.Assert.assertFalse;
+import static junit.framework.Assert.assertTrue;
+import static org.briarproject.bramble.test.TestUtils.deleteTestDirectory;
+import static org.briarproject.bramble.test.TestUtils.getTestDirectory;
+
+public class AndroidAccountManagerTest extends BrambleMockTestCase {
+
+	private final SharedPreferences prefs =
+			context.mock(SharedPreferences.class, "prefs");
+	private final SharedPreferences defaultPrefs =
+			context.mock(SharedPreferences.class, "defaultPrefs");
+	private final DatabaseConfig databaseConfig =
+			context.mock(DatabaseConfig.class);
+	private final CryptoComponent crypto = context.mock(CryptoComponent.class);
+	private final IdentityManager identityManager =
+			context.mock(IdentityManager.class);
+	private final SharedPreferences.Editor
+			editor = context.mock(SharedPreferences.Editor.class);
+	private final Application app;
+	private final ApplicationInfo applicationInfo;
+
+	private final File testDir = getTestDirectory();
+	private final File keyDir = new File(testDir, "key");
+	private final File dbDir = new File(testDir, "db");
+
+	private AndroidAccountManager accountManager;
+
+	public AndroidAccountManagerTest() {
+		context.setImposteriser(ByteBuddyClassImposteriser.INSTANCE);
+		app = context.mock(Application.class);
+		applicationInfo = new ApplicationInfo();
+		applicationInfo.dataDir = testDir.getAbsolutePath();
+	}
+
+	@Before
+	public void setUp() {
+		context.checking(new Expectations() {{
+			allowing(databaseConfig).getDatabaseDirectory();
+			will(returnValue(dbDir));
+			allowing(databaseConfig).getDatabaseKeyDirectory();
+			will(returnValue(keyDir));
+			allowing(app).getApplicationContext();
+			will(returnValue(app));
+		}});
+		accountManager = new AndroidAccountManager(databaseConfig, crypto,
+				identityManager, prefs, app) {
+			@Override
+			SharedPreferences getDefaultSharedPreferences() {
+				return defaultPrefs;
+			}
+		};
+	}
+
+	@Test
+	public void testDeleteAccountClearsSharedPrefsAndDeletesFiles()
+			throws Exception {
+		// Directories 'code_cache', 'lib' and 'shared_prefs' should be spared
+		File codeCacheDir = new File(testDir, "code_cache");
+		File codeCacheFile = new File(codeCacheDir, "file");
+		File libDir = new File(testDir, "lib");
+		File libFile = new File(libDir, "file");
+		File sharedPrefsDir = new File(testDir, "shared_prefs");
+		File sharedPrefsFile = new File(sharedPrefsDir, "file");
+		// Directory 'cache' should be emptied
+		File cacheDir = new File(testDir, "cache");
+		File cacheFile = new File(cacheDir, "file");
+		// Other directories should be deleted
+		File potatoDir = new File(testDir, ".potato");
+		File potatoFile = new File(potatoDir, "file");
+		File filesDir = new File(testDir, "filesDir");
+		File externalCacheDir = new File(testDir, "externalCacheDir");
+		File externalCacheDir1 = new File(testDir, "externalCacheDir1");
+		File externalCacheDir2 = new File(testDir, "externalCacheDir2");
+		File externalMediaDir1 = new File(testDir, "externalMediaDir1");
+		File externalMediaDir2 = new File(testDir, "externalMediaDir2");
+
+		context.checking(new Expectations() {{
+			oneOf(prefs).edit();
+			will(returnValue(editor));
+			oneOf(editor).clear();
+			will(returnValue(editor));
+			oneOf(editor).commit();
+			will(returnValue(true));
+			oneOf(defaultPrefs).edit();
+			will(returnValue(editor));
+			oneOf(editor).clear();
+			will(returnValue(editor));
+			oneOf(editor).commit();
+			will(returnValue(true));
+			allowing(app).getApplicationInfo();
+			will(returnValue(applicationInfo));
+			oneOf(app).getFilesDir();
+			will(returnValue(filesDir));
+			oneOf(app).getCacheDir();
+			will(returnValue(cacheDir));
+			oneOf(app).getExternalCacheDir();
+			will(returnValue(externalCacheDir));
+			oneOf(app).getExternalCacheDirs();
+			will(returnValue(
+					new File[] {externalCacheDir1, externalCacheDir2}));
+			oneOf(app).getExternalMediaDirs();
+			will(returnValue(
+					new File[] {externalMediaDir1, externalMediaDir2}));
+		}});
+
+		assertTrue(dbDir.mkdirs());
+		assertTrue(keyDir.mkdirs());
+		assertTrue(codeCacheDir.mkdirs());
+		assertTrue(codeCacheFile.createNewFile());
+		assertTrue(libDir.mkdirs());
+		assertTrue(libFile.createNewFile());
+		assertTrue(sharedPrefsDir.mkdirs());
+		assertTrue(sharedPrefsFile.createNewFile());
+		assertTrue(cacheDir.mkdirs());
+		assertTrue(cacheFile.createNewFile());
+		assertTrue(potatoDir.mkdirs());
+		assertTrue(potatoFile.createNewFile());
+		assertTrue(filesDir.mkdirs());
+		assertTrue(externalCacheDir.mkdirs());
+		assertTrue(externalCacheDir1.mkdirs());
+		assertTrue(externalCacheDir2.mkdirs());
+		assertTrue(externalMediaDir1.mkdirs());
+		assertTrue(externalMediaDir2.mkdirs());
+
+		accountManager.deleteAccount();
+
+		assertFalse(dbDir.exists());
+		assertFalse(keyDir.exists());
+		assertTrue(codeCacheDir.exists());
+		assertTrue(codeCacheFile.exists());
+		assertTrue(libDir.exists());
+		assertTrue(libFile.exists());
+		assertTrue(sharedPrefsDir.exists());
+		assertTrue(sharedPrefsFile.exists());
+		assertTrue(cacheDir.exists());
+		assertFalse(cacheFile.exists());
+		assertFalse(potatoDir.exists());
+		assertFalse(potatoFile.exists());
+		assertFalse(filesDir.exists());
+		assertFalse(externalCacheDir.exists());
+		assertFalse(externalCacheDir1.exists());
+		assertFalse(externalCacheDir2.exists());
+		assertFalse(externalMediaDir1.exists());
+		assertFalse(externalMediaDir2.exists());
+	}
+
+	@After
+	public void tearDown() {
+		deleteTestDirectory(testDir);
+	}
+}

bramble-android/witness.gradle

@@ -0,0 +1,67 @@
+dependencyVerification {
+    verify = [
+        'androidx.annotation:annotation:1.5.0:annotation-1.5.0.jar:261fb7c0210858500bab66d34354972a75166ab4182add283780b05513d6ec4a',
+        'cglib:cglib:3.2.8:cglib-3.2.8.jar:3f64de999ecc5595dc84ca8ff0879d8a34c8623f9ef3c517a53ed59023fcb9db',
+        'com.google.code.findbugs:annotations:3.0.1:annotations-3.0.1.jar:6b47ff0a6de0ce17cbedc3abb0828ca5bce3009d53ea47b3723ff023c4742f79',
+        'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
+        'com.google.dagger:dagger-compiler:2.45:dagger-compiler-2.45.jar:5617dfb994537dba5b41f3744a6dd13ec3cd99789c065e0d5c6fa9f21cf7ca25',
+        'com.google.dagger:dagger-producers:2.45:dagger-producers-2.45.jar:a05abb4c3ccf6bb0f056bdcb5ef973898ecf172952ab5948a824aeea6c86ecaa',
+        'com.google.dagger:dagger-spi:2.45:dagger-spi-2.45.jar:7cd6f0b09d88e64a9c97bc80e544ab8ac8fdee9301754413585a74cf64222b27',
+        'com.google.dagger:dagger:2.45:dagger-2.45.jar:f011cae7d2c0fb7ea17c34e05bc10e768b1081a5892ad019cf1fdb0e125c49c1',
+        'com.google.devtools.ksp:symbol-processing-api:1.7.0-1.0.6:symbol-processing-api-1.7.0-1.0.6.jar:adc29417be5ca9ff42118105fea4e36d9ef44987abfc41432309371a60198941',
+        'com.google.errorprone:error_prone_annotations:2.7.1:error_prone_annotations-2.7.1.jar:cd5257c08a246cf8628817ae71cb822be192ef91f6881ca4a3fcff4f1de1cff3',
+        '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:failureaccess:1.0.1:failureaccess-1.0.1.jar:a171ee4c734dd2da837e4b16be9df4661afab72a41adaf31eb84dfdaf936ca26',
+        'com.google.guava:guava:31.0.1-jre:guava-31.0.1-jre.jar:d5be94d65e87bd219fb3193ad1517baa55a3b88fc91d21cf735826ab5af087b9',
+        'com.google.guava:listenablefuture:9999.0-empty-to-avoid-conflict-with-guava:listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar:b372a037d4230aa57fbeffdef30fd6123f9c0c2db85d0aced00c91b974f33f99',
+        'com.google.j2objc:j2objc-annotations:1.3:j2objc-annotations-1.3.jar:21af30c92267bd6122c0e0b4d20cccb6641a37eaf956c6540ec471d584e64a7b',
+        'com.squareup:javapoet:1.13.0:javapoet-1.13.0.jar:4c7517e848a71b36d069d12bb3bf46a70fd4cda3105d822b0ed2e19c00b69291',
+        'com.squareup:kotlinpoet:1.11.0:kotlinpoet-1.11.0.jar:2887ada1ca03dd83baa2758640d87e840d1907564db0ef88d2289c868a980492',
+        'javax.annotation:jsr250-api:1.0:jsr250-api-1.0.jar:a1a922d0d9b6d183ed3800dfac01d1e1eb159f0e8c6f94736931c1def54a941f',
+        'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
+        'junit:junit:4.13.2:junit-4.13.2.jar:8e495b634469d64fb8acfa3495a065cbacc8a0fff55ce1e31007be4c16dc57d3',
+        'net.bytebuddy:byte-buddy:1.9.12:byte-buddy-1.9.12.jar:3688c3d434bebc3edc5516296a2ed0f47b65e451071b4afecad84f902f0efc11',
+        'net.jcip:jcip-annotations:1.0:jcip-annotations-1.0.jar:be5805392060c71474bf6c9a67a099471274d30b83eef84bfc4e0889a4f1dcc0',
+        'net.ltgt.gradle.incap:incap:0.2:incap-0.2.jar:b625b9806b0f1e4bc7a2e3457119488de3cd57ea20feedd513db070a573a4ffd',
+        'org.apache-extras.beanshell:bsh:2.0b6:bsh-2.0b6.jar:a17955976070c0573235ee662f2794a78082758b61accffce8d3f8aedcd91047',
+        'org.briarproject:dont-kill-me-lib:0.2.7:dont-kill-me-lib-0.2.7.aar:8a9540941fd927e1c127096a7a9b4aa61ce2f2965d2e24f849be92f9e57213c4',
+        'org.briarproject:jtorctl:0.5:jtorctl-0.5.jar:43f8c7d390169772b9a2c82ab806c8414c136a2a8636c555e22754bb7260793b',
+        'org.briarproject:null-safety:0.1:null-safety-0.1.jar:161760de5e838cb982bafa973df820675d4397098e9a91637a36a306d43ba011',
+        'org.briarproject:obfs4proxy-android:0.0.14-tor2:obfs4proxy-android-0.0.14-tor2.jar:a0a93770d6760ce57d9dbd31cc7177687374e00c3361dac22ab75e3b6e0f289e',
+        'org.briarproject:onionwrapper-android:0.0.4:onionwrapper-android-0.0.4.aar:d761854dac454616b3e0ca099b2cd17060365ce4316afe495cc7ae86b6c81d15',
+        'org.briarproject:onionwrapper-core:0.0.4:onionwrapper-core-0.0.4.jar:28a01a62e96aa763989a8afc325abd3bee54f8021269f91aa48b247a6e717870',
+        'org.briarproject:snowflake-android:2.5.1:snowflake-android-2.5.1.jar:88ec81c17b1b6fa884d06839dec0330e328b45c89f88c970a213ce91ca8eac87',
+        'org.briarproject:tor-android:0.4.7.13-2:tor-android-0.4.7.13-2.jar:453fd463b234a2104edd7f0d02d0649cbb5c5efbe47a76df3828f55a3f90f8b5',
+        'org.checkerframework:checker-compat-qual:2.5.5:checker-compat-qual-2.5.5.jar:11d134b245e9cacc474514d2d66b5b8618f8039a1465cdc55bbc0b34e0008b7a',
+        'org.checkerframework:checker-qual:3.12.0:checker-qual-3.12.0.jar:ff10785ac2a357ec5de9c293cb982a2cbb605c0309ea4cc1cb9b9bc6dbe7f3cb',
+        'org.hamcrest:hamcrest-core:2.1:hamcrest-core-2.1.jar:e09109e54a289d88506b9bfec987ddd199f4217c9464132668351b9a4f00bee9',
+        'org.hamcrest:hamcrest-library:2.1:hamcrest-library-2.1.jar:b7e2b6895b3b679f0e47b6380fda391b225e9b78505db9d8bdde8d3cc8d52a21',
+        'org.hamcrest:hamcrest:2.1:hamcrest-2.1.jar:ba93b2e3a562322ba432f0a1b53addcc55cb188253319a020ed77f824e692050',
+        'org.jacoco:org.jacoco.agent:0.8.7:org.jacoco.agent-0.8.7.jar:9cbcc986e0fbe821a78ff1f8f7d5216f200e5eb124e7f6837d1dc4a77b28b143',
+        'org.jacoco:org.jacoco.ant:0.8.7:org.jacoco.ant-0.8.7.jar:97ca96a382c3f23a44d8eb4c4e6c3742a30cb8005774a76ced0fc4806ce49605',
+        'org.jacoco:org.jacoco.core:0.8.7:org.jacoco.core-0.8.7.jar:ad7739b5fb5969aa1a8aead3d74ed54dc82ed012f1f10f336bd1b96e71c1a13c',
+        'org.jacoco:org.jacoco.report:0.8.7:org.jacoco.report-0.8.7.jar:cc89258623700a6c932592153cb528785876b6da183d5431f97efbba6f020e5b',
+        'org.jetbrains.kotlin:kotlin-reflect:1.6.10:kotlin-reflect-1.6.10.jar:3277ac102ae17aad10a55abec75ff5696c8d109790396434b496e75087854203',
+        'org.jetbrains.kotlin:kotlin-stdlib-common:1.7.0:kotlin-stdlib-common-1.7.0.jar:59c6ff64fe9a6604afce03e8aaa75f83586c6030ac71fb0b34ee7cdefed3618f',
+        'org.jetbrains.kotlin:kotlin-stdlib-common:1.8.0:kotlin-stdlib-common-1.8.0.jar:78ef93b59e603cc0fe51def9bd4c037b07cbace3b3b7806d1a490a42bc1f4cb2',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.0:kotlin-stdlib-jdk7-1.7.0.jar:07e91be9b2ca20672d2bdb7e181b766e73453a2da13492b5ddaee8fa47aea239',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.8.0:kotlin-stdlib-jdk7-1.8.0.jar:4c889d1d9803f5f2eb6c1592a6b7e62369ac7660c9eee15aba16fec059163666',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.0:kotlin-stdlib-jdk8-1.7.0.jar:cf058e11db1dfc9944680c8c61b95ac689aaaa8a3eb30bced028100f038f030b',
+        'org.jetbrains.kotlin:kotlin-stdlib:1.7.0:kotlin-stdlib-1.7.0.jar:aa88e9625577957f3249a46cb6e166ee09b369e600f7a11d148d16b0a6d87f05',
+        'org.jetbrains.kotlin:kotlin-stdlib:1.8.0:kotlin-stdlib-1.8.0.jar:c77bef8774640b9fb9d6e217459ff220dae59878beb7d2e4b430506feffc654e',
+        'org.jetbrains.kotlinx:kotlinx-metadata-jvm:0.5.0:kotlinx-metadata-jvm-0.5.0.jar:ca063a96639b08b9eaa0de4d65e899480740a6efbe28ab9a8681a2ced03055a4',
+        'org.jetbrains:annotations:13.0:annotations-13.0.jar:ace2a10dc8e2d5fd34925ecac03e4988b2c0f851650c94b8cef49ba1bd111478',
+        'org.jmock:jmock-imposters:2.12.0:jmock-imposters-2.12.0.jar:3b836269745a137c9b2347e8d7c2104845b126ef04f012d6bfd94f1a7dea7b09',
+        'org.jmock:jmock-junit4:2.12.0:jmock-junit4-2.12.0.jar:3233062fc889637c151a24f1ee086bad04321ab7d8264fef279daff0fa27205b',
+        'org.jmock:jmock-legacy:2.12.0:jmock-legacy-2.12.0.jar:dea3a9cca653d082e2fe7e40232e982fe03a9984c7d67ceff24f3e03fe580dcd',
+        'org.jmock:jmock-testjar:2.12.0:jmock-testjar-2.12.0.jar:efefbcf6cd294d0e29f0c46eb2a3380d4ca4e1763ff719c69e2f2ac62f564a04',
+        'org.jmock:jmock:2.12.0:jmock-2.12.0.jar:266d07314c0cd343c46ff8a55601272de8cf406807caf55e6f313295f83d10be',
+        'org.objenesis:objenesis:3.0.1:objenesis-3.0.1.jar:7a8ff780b9ff48415d7c705f60030b0acaa616e7f823c98eede3b63508d4e984',
+        'org.ow2.asm:asm-analysis:9.1:asm-analysis-9.1.jar:81a88041b1b8beda5a8a99646098046c48709538270c49def68abff25ac3be34',
+        'org.ow2.asm:asm-commons:9.1:asm-commons-9.1.jar:afcb26dc1fc12c0c4a99ada670908dd82e18dfc488caf5ee92546996b470c00c',
+        'org.ow2.asm:asm-tree:9.1:asm-tree-9.1.jar:fd00afa49e9595d7646205b09cecb4a776a8ff0ba06f2d59b8f7bf9c704b4a73',
+        'org.ow2.asm:asm:7.1:asm-7.1.jar:4ab2fa2b6d2cc9ccb1eaa05ea329c407b47b13ed2915f62f8c4b8cc96258d4de',
+        'org.ow2.asm:asm:9.1:asm-9.1.jar:cda4de455fab48ff0bcb7c48b4639447d4de859a7afc30a094a986f0936beba2',
+    ]
+}

bramble-api/build.gradle

@@ -0,0 +1,34 @@
+apply plugin: 'java-library'
+sourceCompatibility = 1.8
+targetCompatibility = 1.8
+
+apply plugin: 'ru.vyarus.animalsniffer'
+apply plugin: 'witness'
+apply from: 'witness.gradle'
+
+dependencies {
+	api 'org.briarproject:null-safety:0.1'
+	api 'com.google.code.findbugs:jsr305:3.0.2'
+	api 'javax.inject:javax.inject:1'
+	api "com.google.dagger:dagger:$dagger_version"
+
+	implementation "com.fasterxml.jackson.core:jackson-annotations:$jackson_version"
+
+	testImplementation "junit:junit:$junit_version"
+	testImplementation "org.jmock:jmock:$jmock_version"
+	testImplementation "org.jmock:jmock-junit4:$jmock_version"
+
+	signature 'org.codehaus.mojo.signature:java16:1.1@signature'
+}
+
+// needed to make test output available to bramble-core and briar-core
+configurations {
+	testOutput.extendsFrom(testCompile)
+}
+task jarTest(type: Jar, dependsOn: testClasses) {
+	from sourceSets.test.output, sourceSets.main.output
+	classifier = 'test'
+}
+artifacts {
+	testOutput jarTest
+}

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

@@ -0,0 +1,63 @@
+package org.briarproject.bramble.api;
+
+import org.briarproject.bramble.util.StringUtils;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.util.Arrays;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.ThreadSafe;
+
+/**
+ * A wrapper around a byte array, to allow it to be stored in maps etc.
+ */
+@ThreadSafe
+@NotNullByDefault
+public class Bytes implements Comparable<Bytes> {
+
+	private final byte[] bytes;
+
+	private int hashCode = -1;
+
+	public Bytes(byte[] bytes) {
+		this.bytes = bytes;
+	}
+
+	public byte[] getBytes() {
+		return bytes;
+	}
+
+	@Override
+	public int hashCode() {
+		// Thread-safe because if two or more threads check and update the
+		// value, they'll calculate the same value
+		if (hashCode == -1) hashCode = Arrays.hashCode(bytes);
+		return hashCode;
+	}
+
+	@Override
+	public boolean equals(@Nullable Object o) {
+		return o instanceof Bytes && Arrays.equals(bytes, ((Bytes) o).bytes);
+	}
+
+	@Override
+	public int compareTo(Bytes other) {
+		return compare(bytes, other.bytes);
+	}
+
+	@Override
+	public String toString() {
+		return getClass().getSimpleName() +
+				"(" + StringUtils.toHexString(getBytes()) + ")";
+	}
+
+	public static int compare(byte[] a, byte[] b) {
+		int length = Math.min(a.length, b.length);
+		for (int i = 0; i < length; i++) {
+			int aUnsigned = a[i] & 0xFF, bUnsigned = b[i] & 0xFF;
+			if (aUnsigned < bUnsigned) return -1;
+			if (aUnsigned > bUnsigned) return 1;
+		}
+		return a.length - b.length;
+	}
+}

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

@@ -0,0 +1,6 @@
+package org.briarproject.bramble.api;
+
+public interface Cancellable {
+
+	void cancel();
+}

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

@@ -0,0 +1,9 @@
+package org.briarproject.bramble.api;
+
+import org.briarproject.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface Consumer<T> {
+
+	void accept(T t);
+}

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

@@ -0,0 +1,19 @@
+package org.briarproject.bramble.api;
+
+/**
+ * Interface for specifying which features are enabled in a build.
+ */
+public interface FeatureFlags {
+
+	boolean shouldEnableImageAttachments();
+
+	boolean shouldEnableProfilePictures();
+
+	boolean shouldEnableDisappearingMessages();
+
+	boolean shouldEnablePrivateGroupsInCore();
+
+	boolean shouldEnableForumsInCore();
+
+	boolean shouldEnableBlogsInCore();
+}

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

@@ -0,0 +1,9 @@
+package org.briarproject.bramble.api;
+
+import java.io.IOException;
+
+/**
+ * An exception that indicates an unrecoverable formatting error.
+ */
+public class FormatException extends IOException {
+}

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

@@ -0,0 +1,101 @@
+package org.briarproject.bramble.api;
+
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+
+import javax.annotation.concurrent.NotThreadSafe;
+
+@NotThreadSafe
+@NotNullByDefault
+public class Multiset<T> {
+
+	private final Map<T, Integer> map = new HashMap<>();
+
+	private int total = 0;
+
+	/**
+	 * Returns how many items the multiset contains in total.
+	 */
+	public int getTotal() {
+		return total;
+	}
+
+	/**
+	 * Returns how many unique items the multiset contains.
+	 */
+	public int getUnique() {
+		return map.size();
+	}
+
+	/**
+	 * Returns how many of the given item the multiset contains.
+	 */
+	public int getCount(T t) {
+		Integer count = map.get(t);
+		return count == null ? 0 : count;
+	}
+
+	/**
+	 * Adds the given item to the multiset and returns how many of the item
+	 * the multiset now contains.
+	 */
+	public int add(T t) {
+		Integer count = map.get(t);
+		if (count == null) count = 0;
+		map.put(t, count + 1);
+		total++;
+		return count + 1;
+	}
+
+	/**
+	 * Removes the given item from the multiset and returns how many of the
+	 * item the multiset now contains.
+	 * @throws NoSuchElementException if the item is not in the multiset.
+	 */
+	public int remove(T t) {
+		Integer count = map.get(t);
+		if (count == null) throw new NoSuchElementException();
+		if (count == 1) map.remove(t);
+		else map.put(t, count - 1);
+		total--;
+		return count - 1;
+	}
+
+	/**
+	 * Removes all occurrences of the given item from the multiset.
+	 */
+	public int removeAll(T t) {
+		Integer count = map.remove(t);
+		if (count == null) return 0;
+		total -= count;
+		return count;
+	}
+
+	/**
+	 * Returns true if the multiset contains any occurrences of the given item.
+	 */
+	public boolean contains(T t) {
+		return map.containsKey(t);
+	}
+
+	/**
+	 * Removes all items from the multiset.
+	 */
+	public void clear() {
+		map.clear();
+		total = 0;
+	}
+
+	/**
+	 * Returns the set of unique items the multiset contains. The returned set
+	 * is unmodifiable.
+	 */
+	public Set<T> keySet() {
+		return Collections.unmodifiableSet(map.keySet());
+	}
+}

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

@@ -0,0 +1,10 @@
+package org.briarproject.bramble.api;
+
+import org.briarproject.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface Nameable {
+
+	String getName();
+
+}

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

@@ -0,0 +1,26 @@
+package org.briarproject.bramble.api;
+
+import org.briarproject.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;
+	}
+}

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

@@ -0,0 +1,9 @@
+package org.briarproject.bramble.api;
+
+import org.briarproject.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface Predicate<T> {
+
+	boolean test(T t);
+}

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

@@ -0,0 +1,88 @@
+package org.briarproject.bramble.api;
+
+import org.briarproject.bramble.util.StringUtils;
+
+import java.util.ArrayList;
+import java.util.Hashtable;
+import java.util.List;
+import java.util.Map;
+
+import javax.annotation.Nullable;
+
+public abstract class StringMap extends Hashtable<String, String> {
+
+	protected StringMap(Map<String, String> m) {
+		super(m);
+	}
+
+	protected StringMap() {
+		super();
+	}
+
+	public boolean getBoolean(String key, boolean defaultValue) {
+		String s = get(key);
+		if (s == null) return defaultValue;
+		if ("true".equals(s)) return true;
+		if ("false".equals(s)) return false;
+		return defaultValue;
+	}
+
+	public void putBoolean(String key, boolean value) {
+		put(key, String.valueOf(value));
+	}
+
+	public int getInt(String key, int defaultValue) {
+		String s = get(key);
+		if (s == null) return defaultValue;
+		try {
+			return Integer.valueOf(s);
+		} catch (NumberFormatException e) {
+			return defaultValue;
+		}
+	}
+
+	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));
+	}
+
+	@Nullable
+	public int[] getIntArray(String key) {
+		String s = get(key);
+		if (s == null) return null;
+		// Handle empty string because "".split(",") returns {""}
+		if (s.length() == 0) return new int[0];
+		String[] intStrings = s.split(",");
+		int[] ints = new int[intStrings.length];
+		try {
+			for (int i = 0; i < ints.length; i++) {
+				ints[i] = Integer.parseInt(intStrings[i]);
+			}
+		} catch (NumberFormatException e) {
+			return null;
+		}
+		return ints;
+	}
+
+	public void putIntArray(String key, int[] value) {
+		List<String> intStrings = new ArrayList<>();
+		for (int integer : value) {
+			intStrings.add(String.valueOf(integer));
+		}
+		// Puts empty string if input array value is empty
+		put(key, StringUtils.join(intStrings, ","));
+	}
+}

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

@@ -0,0 +1,20 @@
+package org.briarproject.bramble.api;
+
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.ThreadSafe;
+
+@ThreadSafe
+@NotNullByDefault
+public class UniqueId extends Bytes {
+
+	/**
+	 * The length of a unique identifier in bytes.
+	 */
+	public static final int LENGTH = 32;
+
+	public UniqueId(byte[] id) {
+		super(id);
+		if (id.length != LENGTH) throw new IllegalArgumentException();
+	}
+}

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

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

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

@@ -0,0 +1,35 @@
+package org.briarproject.bramble.api;
+
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.lang.ref.WeakReference;
+
+import javax.annotation.concurrent.GuardedBy;
+import javax.inject.Provider;
+
+/**
+ * A {@link Provider} that keeps a {@link WeakReference} to the last provided
+ * instance and provides the same instance again until the instance is garbage
+ * collected.
+ */
+@NotNullByDefault
+public abstract class WeakSingletonProvider<T> implements Provider<T> {
+
+	private final Object lock = new Object();
+	@GuardedBy("lock")
+	private WeakReference<T> ref = new WeakReference<>(null);
+
+	@Override
+	public T get() {
+		synchronized (lock) {
+			T instance = ref.get();
+			if (instance == null) {
+				instance = createInstance();
+				ref = new WeakReference<>(instance);
+			}
+			return instance;
+		}
+	}
+
+	public abstract T createInstance();
+}

bramble-api/src/main/java/org/briarproject/bramble/api/account/AccountManager.java

@@ -0,0 +1,71 @@
+package org.briarproject.bramble.api.account;
+
+import org.briarproject.bramble.api.crypto.DecryptionException;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.identity.IdentityManager;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import javax.annotation.Nullable;
+
+@NotNullByDefault
+public interface AccountManager {
+
+	/**
+	 * Returns true if the manager has the database key. This will be false
+	 * before {@link #createAccount(String, String)} or {@link #signIn(String)}
+	 * has been called, and true after {@link #createAccount(String, String)}
+	 * or {@link #signIn(String)} has returned true, until
+	 * {@link #deleteAccount()} is called or the process exits.
+	 */
+	boolean hasDatabaseKey();
+
+	/**
+	 * Returns the database key if the manager has it. This will be null
+	 * before {@link #createAccount(String, String)} or {@link #signIn(String)}
+	 * has been called, and non-null after
+	 * {@link #createAccount(String, String)} or {@link #signIn(String)} has
+	 * returned true, until {@link #deleteAccount()} is called or the process
+	 * exits.
+	 */
+	@Nullable
+	SecretKey getDatabaseKey();
+
+	/**
+	 * Returns true if the encrypted database key can be loaded from disk.
+	 */
+	boolean accountExists();
+
+	/**
+	 * Creates an identity with the given name and registers it with the
+	 * {@link IdentityManager}. Creates a database key, encrypts it with the
+	 * given password and stores it on disk. {@link #accountExists()} will
+	 * return true after this method returns true.
+	 */
+	boolean createAccount(String name, String password);
+
+	/**
+	 * Deletes all account state from disk. {@link #accountExists()} will
+	 * return false after this method returns.
+	 */
+	void deleteAccount();
+
+	/**
+	 * Loads the encrypted database key from disk and decrypts it with the
+	 * given password.
+	 *
+	 * @throws DecryptionException If the database key could not be loaded and
+	 * decrypted.
+	 */
+	void signIn(String password) throws DecryptionException;
+
+	/**
+	 * Loads the encrypted database key from disk, decrypts it with the old
+	 * password, encrypts it with the new password, and stores it on disk,
+	 * replacing the old key.
+	 *
+	 * @throws DecryptionException If the database key could not be loaded and
+	 * decrypted.
+	 */
+	void changePassword(String oldPassword, String newPassword)
+			throws DecryptionException;
+}

bramble-api/src/main/java/org/briarproject/bramble/api/battery/BatteryManager.java

@@ -0,0 +1,6 @@
+package org.briarproject.bramble.api.battery;
+
+public interface BatteryManager {
+
+	boolean isCharging();
+}

bramble-api/src/main/java/org/briarproject/bramble/api/battery/event/BatteryEvent.java

@@ -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;
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/cleanup/CleanupHook.java

@@ -0,0 +1,29 @@
+package org.briarproject.bramble.api.cleanup;
+
+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.sync.GroupId;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.util.Collection;
+
+/**
+ * An interface for registering a hook with the {@link CleanupManager}
+ * that will be called when a message's cleanup deadline is reached.
+ */
+@NotNullByDefault
+public interface CleanupHook {
+
+	/**
+	 * Called when the cleanup deadlines of one or more messages are reached.
+	 * <p>
+	 * The callee is not required to delete the messages, but the hook won't be
+	 * called again for these messages unless another cleanup timer is set (see
+	 * {@link DatabaseComponent#setCleanupTimerDuration(Transaction, MessageId, long)}
+	 * and {@link DatabaseComponent#startCleanupTimer(Transaction, MessageId)}).
+	 */
+	void deleteMessages(Transaction txn, GroupId g,
+			Collection<MessageId> messageIds) throws DbException;
+}

bramble-api/src/main/java/org/briarproject/bramble/api/cleanup/CleanupManager.java

@@ -0,0 +1,42 @@
+package org.briarproject.bramble.api.cleanup;
+
+import org.briarproject.bramble.api.cleanup.event.CleanupTimerStartedEvent;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.sync.ClientId;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+/**
+ * The CleanupManager is responsible for tracking the cleanup deadlines of
+ * messages and passing them to their respective
+ * {@link CleanupHook CleanupHooks} when the deadlines are reached.
+ * <p>
+ * The CleanupManager responds to
+ * {@link CleanupTimerStartedEvent CleanupTimerStartedEvents} broadcast by the
+ * {@link DatabaseComponent}.
+ * <p>
+ * See {@link DatabaseComponent#setCleanupTimerDuration(Transaction, MessageId, long)},
+ * {@link DatabaseComponent#startCleanupTimer(Transaction, MessageId)},
+ * {@link DatabaseComponent#stopCleanupTimer(Transaction, MessageId)}.
+ */
+@NotNullByDefault
+public interface CleanupManager {
+
+	/**
+	 * When scheduling a cleanup task we overshoot the deadline by this many
+	 * milliseconds to reduce the number of tasks that need to be scheduled
+	 * when messages have cleanup deadlines that are close together.
+	 */
+	long BATCH_DELAY_MS = 1000;
+
+	/**
+	 * Registers a hook to be called when messages are due for cleanup.
+	 * This method should be called before
+	 * {@link LifecycleManager#startServices(SecretKey)}.
+	 */
+	void registerCleanupHook(ClientId c, int majorVersion,
+			CleanupHook hook);
+}

bramble-api/src/main/java/org/briarproject/bramble/api/cleanup/event/CleanupTimerStartedEvent.java

@@ -0,0 +1,32 @@
+package org.briarproject.bramble.api.cleanup.event;
+
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that is broadcast when a message's cleanup timer is started.
+ */
+@Immutable
+@NotNullByDefault
+public class CleanupTimerStartedEvent extends Event {
+
+	private final MessageId messageId;
+	private final long cleanupDeadline;
+
+	public CleanupTimerStartedEvent(MessageId messageId,
+			long cleanupDeadline) {
+		this.messageId = messageId;
+		this.cleanupDeadline = cleanupDeadline;
+	}
+
+	public MessageId getMessageId() {
+		return messageId;
+	}
+
+	public long getCleanupDeadline() {
+		return cleanupDeadline;
+	}
+}

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

@@ -0,0 +1,68 @@
+package org.briarproject.bramble.api.client;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.data.BdfDictionary;
+import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.data.MetadataParser;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Metadata;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.sync.InvalidMessageException;
+import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.sync.validation.IncomingMessageHook;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+public abstract class BdfIncomingMessageHook implements IncomingMessageHook {
+
+	protected final DatabaseComponent db;
+	protected final ClientHelper clientHelper;
+	protected final MetadataParser metadataParser;
+
+	protected BdfIncomingMessageHook(DatabaseComponent db,
+			ClientHelper clientHelper, MetadataParser metadataParser) {
+		this.db = db;
+		this.clientHelper = clientHelper;
+		this.metadataParser = metadataParser;
+	}
+
+	/**
+	 * Called once for each incoming message that passes validation.
+	 * <p>
+	 * If an unexpected exception occurs while handling data that is assumed
+	 * to be valid (e.g. locally created metadata), it may be sensible to
+	 * rethrow the unexpected exception as a DbException so that delivery is
+	 * attempted again at next startup. This will allow delivery to succeed if
+	 * the unexpected exception was caused by a bug that has subsequently been
+	 * fixed.
+	 *
+	 * @param txn A read-write transaction
+	 * @throws DbException if a database error occurs while delivering the
+	 * message. Delivery will be attempted again at next startup. Throwing
+	 * this exception has the same effect as returning
+	 * {@link DeliveryAction#DEFER}.
+	 * @throws FormatException if the message is invalid in the context of its
+	 * dependencies. The message and any dependents will be marked as invalid
+	 * and deleted along with their metadata. Throwing this exception has the
+	 * same effect as returning {@link DeliveryAction#REJECT}.
+	 */
+	protected abstract DeliveryAction incomingMessage(Transaction txn,
+			Message m, BdfList body, BdfDictionary meta)
+			throws DbException, FormatException;
+
+	@Override
+	public DeliveryAction incomingMessage(Transaction txn, Message m,
+			Metadata meta) throws DbException, InvalidMessageException {
+		try {
+			BdfList body = clientHelper.toList(m);
+			BdfDictionary metaDictionary = metadataParser.parse(meta);
+			return incomingMessage(txn, m, body, metaDictionary);
+		} catch (FormatException e) {
+			throw new InvalidMessageException(e);
+		}
+	}
+}

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

@@ -0,0 +1,36 @@
+package org.briarproject.bramble.api.client;
+
+import org.briarproject.bramble.api.data.BdfDictionary;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.util.Collection;
+import java.util.Collections;
+
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+public class BdfMessageContext {
+
+	private final BdfDictionary dictionary;
+	private final Collection<MessageId> dependencies;
+
+	public BdfMessageContext(BdfDictionary dictionary,
+			Collection<MessageId> dependencies) {
+		this.dictionary = dictionary;
+		this.dependencies = dependencies;
+	}
+
+	public BdfMessageContext(BdfDictionary dictionary) {
+		this(dictionary, Collections.emptyList());
+	}
+
+	public BdfDictionary getDictionary() {
+		return dictionary;
+	}
+
+	public Collection<MessageId> getDependencies() {
+		return dependencies;
+	}
+}

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

@@ -0,0 +1,68 @@
+package org.briarproject.bramble.api.client;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.data.MetadataEncoder;
+import org.briarproject.bramble.api.db.Metadata;
+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.validation.MessageValidator;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.util.logging.Logger;
+
+import javax.annotation.concurrent.Immutable;
+
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.transport.TransportConstants.MAX_CLOCK_DIFFERENCE;
+
+@Immutable
+@NotNullByDefault
+public abstract class BdfMessageValidator implements MessageValidator {
+
+	protected static final Logger LOG =
+			getLogger(BdfMessageValidator.class.getName());
+
+	protected final ClientHelper clientHelper;
+	protected final MetadataEncoder metadataEncoder;
+	protected final Clock clock;
+	protected final boolean canonical;
+
+	protected BdfMessageValidator(ClientHelper clientHelper,
+			MetadataEncoder metadataEncoder, Clock clock, boolean canonical) {
+		this.clientHelper = clientHelper;
+		this.metadataEncoder = metadataEncoder;
+		this.clock = clock;
+		this.canonical = canonical;
+	}
+
+	protected BdfMessageValidator(ClientHelper clientHelper,
+			MetadataEncoder metadataEncoder, Clock clock) {
+		this(clientHelper, metadataEncoder, clock, true);
+	}
+
+	protected abstract BdfMessageContext validateMessage(Message m, Group g,
+			BdfList body) throws InvalidMessageException, FormatException;
+
+	@Override
+	public MessageContext validateMessage(Message m, Group g)
+			throws InvalidMessageException {
+		// Reject the message if it's too far in the future
+		long now = clock.currentTimeMillis();
+		if (m.getTimestamp() - now > MAX_CLOCK_DIFFERENCE) {
+			throw new InvalidMessageException(
+					"Timestamp is too far in the future");
+		}
+		try {
+			BdfList bodyList = clientHelper.toList(m, canonical);
+			BdfMessageContext result = validateMessage(m, g, bodyList);
+			Metadata meta = metadataEncoder.encode(result.getDictionary());
+			return new MessageContext(meta, result.getDependencies());
+		} catch (FormatException e) {
+			throw new InvalidMessageException(e);
+		}
+	}
+}

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

@@ -0,0 +1,160 @@
+package org.briarproject.bramble.api.client;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.crypto.PrivateKey;
+import org.briarproject.bramble.api.crypto.PublicKey;
+import org.briarproject.bramble.api.data.BdfDictionary;
+import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.mailbox.MailboxUpdate;
+import org.briarproject.bramble.api.mailbox.MailboxVersion;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.security.GeneralSecurityException;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+
+@NotNullByDefault
+public interface ClientHelper {
+
+	void addLocalMessage(Message m, BdfDictionary metadata, boolean shared)
+			throws DbException, FormatException;
+
+	void addLocalMessage(Transaction txn, Message m, BdfDictionary metadata,
+			boolean shared, boolean temporary)
+			throws DbException, FormatException;
+
+	Message createMessage(GroupId g, long timestamp, byte[] body);
+
+	Message createMessage(GroupId g, long timestamp, BdfList body)
+			throws FormatException;
+
+	Message createMessageForStoringMetadata(GroupId g);
+
+	Message getMessage(MessageId m) throws DbException;
+
+	Message getMessage(Transaction txn, MessageId m) throws DbException;
+
+	BdfList getMessageAsList(MessageId m) throws DbException, FormatException;
+
+	BdfList getMessageAsList(Transaction txn, MessageId m) throws DbException,
+			FormatException;
+
+	BdfList getMessageAsList(Transaction txn, MessageId m, boolean canonical)
+			throws DbException, FormatException;
+
+	BdfDictionary getGroupMetadataAsDictionary(GroupId g) throws DbException,
+			FormatException;
+
+	BdfDictionary getGroupMetadataAsDictionary(Transaction txn, GroupId g)
+			throws DbException, FormatException;
+
+	Collection<MessageId> getMessageIds(Transaction txn, GroupId g,
+			BdfDictionary query) throws DbException, FormatException;
+
+	BdfDictionary getMessageMetadataAsDictionary(MessageId m)
+			throws DbException, FormatException;
+
+	BdfDictionary getMessageMetadataAsDictionary(Transaction txn, MessageId m)
+			throws DbException, FormatException;
+
+	Map<MessageId, BdfDictionary> getMessageMetadataAsDictionary(GroupId g)
+			throws DbException, FormatException;
+
+	Map<MessageId, BdfDictionary> getMessageMetadataAsDictionary(
+			Transaction txn, GroupId g) throws DbException, FormatException;
+
+	Map<MessageId, BdfDictionary> getMessageMetadataAsDictionary(GroupId g,
+			BdfDictionary query) throws DbException, FormatException;
+
+	Map<MessageId, BdfDictionary> getMessageMetadataAsDictionary(
+			Transaction txn, GroupId g, BdfDictionary query) throws DbException,
+			FormatException;
+
+	void mergeGroupMetadata(GroupId g, BdfDictionary metadata)
+			throws DbException, FormatException;
+
+	void mergeGroupMetadata(Transaction txn, GroupId g, BdfDictionary metadata)
+			throws DbException, FormatException;
+
+	void mergeMessageMetadata(MessageId m, BdfDictionary metadata)
+			throws DbException, FormatException;
+
+	void mergeMessageMetadata(Transaction txn, MessageId m,
+			BdfDictionary metadata) throws DbException, FormatException;
+
+	byte[] toByteArray(BdfDictionary dictionary) throws FormatException;
+
+	byte[] toByteArray(BdfList list) throws FormatException;
+
+	BdfDictionary toDictionary(byte[] b, int off, int len)
+			throws FormatException;
+
+	BdfDictionary toDictionary(TransportProperties transportProperties);
+
+	BdfDictionary toDictionary(Map<TransportId, TransportProperties> map);
+
+	BdfList toList(byte[] b, int off, int len) throws FormatException;
+
+	BdfList toList(byte[] b) throws FormatException;
+
+	BdfList toList(Message m) throws FormatException;
+
+	BdfList toList(Message m, boolean canonical) throws FormatException;
+
+	BdfList toList(Author a);
+
+	byte[] sign(String label, BdfList toSign, PrivateKey privateKey)
+			throws FormatException, GeneralSecurityException;
+
+	void verifySignature(byte[] signature, String label, BdfList signed,
+			PublicKey publicKey)
+			throws FormatException, GeneralSecurityException;
+
+	Author parseAndValidateAuthor(BdfList author) throws FormatException;
+
+	PublicKey parseAndValidateAgreementPublicKey(byte[] publicKeyBytes)
+			throws FormatException;
+
+	TransportProperties parseAndValidateTransportProperties(
+			BdfDictionary properties) throws FormatException;
+
+	Map<TransportId, TransportProperties> parseAndValidateTransportPropertiesMap(
+			BdfDictionary properties) throws FormatException;
+
+	/**
+	 * Parse and validate the elements of a Mailbox update message.
+	 *
+	 * @return the parsed update message
+	 * @throws FormatException if the message elements are invalid
+	 */
+	MailboxUpdate parseAndValidateMailboxUpdate(BdfList clientSupports,
+			BdfList serverSupports, BdfDictionary properties)
+			throws FormatException;
+
+	List<MailboxVersion> parseMailboxVersionList(BdfList bdfList)
+			throws FormatException;
+
+	/**
+	 * Retrieves the contact ID from the group metadata of the given contact
+	 * group.
+	 */
+	ContactId getContactId(Transaction txn, GroupId contactGroupId)
+			throws DbException;
+
+	/**
+	 * Stores the given contact ID in the group metadata of the given contact
+	 * group.
+	 */
+	void setContactId(Transaction txn, GroupId contactGroupId, ContactId c)
+			throws DbException;
+}

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

@@ -0,0 +1,9 @@
+package org.briarproject.bramble.api.client;
+
+public interface ContactGroupConstants {
+
+	/**
+	 * Group metadata key for associating a contact ID with a contact group.
+	 */
+	String GROUP_KEY_CONTACT_ID = "contactId";
+}

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

@@ -0,0 +1,30 @@
+package org.briarproject.bramble.api.client;
+
+import org.briarproject.bramble.api.contact.Contact;
+import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.sync.ClientId;
+import org.briarproject.bramble.api.sync.Group;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface ContactGroupFactory {
+
+	/**
+	 * Creates a group that is not shared with any contacts.
+	 */
+	Group createLocalGroup(ClientId clientId, int majorVersion);
+
+	/**
+	 * Creates a group for the given client to share with the given contact.
+	 */
+	Group createContactGroup(ClientId clientId, int majorVersion,
+			Contact contact);
+
+	/**
+	 * Creates a group for the given client to share between the given authors
+	 * identified by their AuthorIds.
+	 */
+	Group createContactGroup(ClientId clientId, int majorVersion,
+			AuthorId authorId1, AuthorId authorId2);
+
+}

bramble-api/src/main/java/org/briarproject/bramble/api/connection/ConnectionManager.java

@@ -0,0 +1,86 @@
+package org.briarproject.bramble.api.connection;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.PendingContactId;
+import org.briarproject.bramble.api.plugin.TransportConnectionReader;
+import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.bramble.api.sync.OutgoingSessionRecord;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface ConnectionManager {
+
+	/**
+	 * Manages an incoming connection from a contact over a simplex transport.
+	 */
+	void manageIncomingConnection(TransportId t, TransportConnectionReader r);
+
+	/**
+	 * Manages an incoming connection from a contact via a mailbox.
+	 * <p>
+	 * This method does not mark the tag as recognised until after the data
+	 * has been read from the {@link TransportConnectionReader}, at which
+	 * point the {@link TagController} is called to decide whether the tag
+	 * should be marked as recognised.
+	 */
+	void manageIncomingConnection(TransportId t, TransportConnectionReader r,
+			TagController c);
+
+	/**
+	 * Manages an incoming connection from a contact over a duplex transport.
+	 */
+	void manageIncomingConnection(TransportId t, DuplexTransportConnection d);
+
+	/**
+	 * Manages an incoming handshake connection from a pending contact over a
+	 * duplex transport.
+	 */
+	void manageIncomingConnection(PendingContactId p, TransportId t,
+			DuplexTransportConnection d);
+
+	/**
+	 * Manages an outgoing connection to a contact over a simplex transport.
+	 */
+	void manageOutgoingConnection(ContactId c, TransportId t,
+			TransportConnectionWriter w);
+
+	/**
+	 * Manages an outgoing connection to a contact via a mailbox. The IDs of
+	 * any messages sent or acked are added to the given
+	 * {@link OutgoingSessionRecord}.
+	 */
+	void manageOutgoingConnection(ContactId c, TransportId t,
+			TransportConnectionWriter w, OutgoingSessionRecord sessionRecord);
+
+	/**
+	 * Manages an outgoing connection to a contact over a duplex transport.
+	 */
+	void manageOutgoingConnection(ContactId c, TransportId t,
+			DuplexTransportConnection d);
+
+	/**
+	 * Manages an outgoing handshake connection to a pending contact over a
+	 * duplex transport.
+	 */
+	void manageOutgoingConnection(PendingContactId p, TransportId t,
+			DuplexTransportConnection d);
+
+	/**
+	 * An interface for controlling whether a tag should be marked as
+	 * recognised.
+	 */
+	interface TagController {
+		/**
+		 * This method is only called if a tag was read from the corresponding
+		 * {@link TransportConnectionReader} and recognised.
+		 *
+		 * @param exception True if an exception was thrown while reading from
+		 * the {@link TransportConnectionReader}, after successfully reading
+		 * and recognising the tag.
+		 * @return True if the tag should be marked as recognised.
+		 */
+		boolean shouldMarkTagAsRecognised(boolean exception);
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/connection/ConnectionRegistry.java

@@ -0,0 +1,130 @@
+package org.briarproject.bramble.api.connection;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.PendingContactId;
+import org.briarproject.bramble.api.plugin.PluginConfig;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
+import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
+import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
+import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
+import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionClosedEvent;
+import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionOpenedEvent;
+import org.briarproject.bramble.api.sync.Priority;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.util.Collection;
+
+/**
+ * Keeps track of which contacts are currently connected by which transports.
+ */
+@NotNullByDefault
+public interface ConnectionRegistry {
+
+	/**
+	 * Registers an incoming connection from the given contact over the given
+	 * transport. The connection's {@link Priority priority} can be set later
+	 * via {@link #setPriority(ContactId, TransportId, InterruptibleConnection,
+	 * Priority)} if a priority record is received from the contact.
+	 * <p>
+	 * Broadcasts {@link ConnectionOpenedEvent}. Also broadcasts
+	 * {@link ContactConnectedEvent} if this is the only connection with the
+	 * contact.
+	 */
+	void registerIncomingConnection(ContactId c, TransportId t,
+			InterruptibleConnection conn);
+
+	/**
+	 * Registers an outgoing connection to the given contact over the given
+	 * transport.
+	 * <p>
+	 * Broadcasts {@link ConnectionOpenedEvent}. Also broadcasts
+	 * {@link ContactConnectedEvent} if this is the only connection with the
+	 * contact.
+	 * <p>
+	 * If the registry has any "better" connections with the given contact, the
+	 * given connection will be interrupted. If the registry has any "worse"
+	 * connections with the given contact, those connections will be
+	 * interrupted.
+	 * <p>
+	 * Connection A is considered "better" than connection B if both
+	 * connections have had their priorities set, and either A's transport is
+	 * {@link PluginConfig#getTransportPreferences() preferred} to B's, or
+	 * they use the same transport and A has higher {@link Priority priority}
+	 * than B.
+	 * <p>
+	 * For backward compatibility, connections without priorities are not
+	 * considered better or worse than other connections.
+	 */
+	void registerOutgoingConnection(ContactId c, TransportId t,
+			InterruptibleConnection conn, Priority priority);
+
+	/**
+	 * Unregisters a connection with the given contact over the given transport.
+	 * <p>
+	 * Broadcasts {@link ConnectionClosedEvent}. Also broadcasts
+	 * {@link ContactDisconnectedEvent} if this is the only connection with
+	 * the contact.
+	 */
+	void unregisterConnection(ContactId c, TransportId t,
+			InterruptibleConnection conn, boolean incoming, boolean exception);
+
+	/**
+	 * Sets the {@link Priority priority} of a connection that was previously
+	 * registered via {@link #registerIncomingConnection(ContactId, TransportId,
+	 * InterruptibleConnection)}.
+	 * <p>
+	 * If the registry has any "better" connections with the given contact, the
+	 * given connection will be interrupted. If the registry has any "worse"
+	 * connections with the given contact, those connections will be
+	 * interrupted.
+	 * <p>
+	 * Connection A is considered "better" than connection B if both
+	 * connections have had their priorities set, and either A's transport is
+	 * {@link PluginConfig#getTransportPreferences() preferred} to B's, or
+	 * they use the same transport and A has higher {@link Priority priority}
+	 * than B.
+	 * <p>
+	 * For backward compatibility, connections without priorities are not
+	 * considered better or worse than other connections.
+	 */
+	void setPriority(ContactId c, TransportId t, InterruptibleConnection conn,
+			Priority priority);
+
+	/**
+	 * Returns any contacts that are connected via the given transport.
+	 */
+	Collection<ContactId> getConnectedContacts(TransportId t);
+
+	/**
+	 * Returns any contacts that are connected via the given transport or any
+	 * {@link PluginConfig#getTransportPreferences() better} transport.
+	 */
+	Collection<ContactId> getConnectedOrBetterContacts(TransportId t);
+
+	/**
+	 * Returns true if the given contact is connected via the given transport.
+	 */
+	boolean isConnected(ContactId c, TransportId t);
+
+	/**
+	 * Returns true if the given contact is connected via any transport.
+	 */
+	boolean isConnected(ContactId c);
+
+	/**
+	 * Registers a connection with the given pending contact. Broadcasts
+	 * {@link RendezvousConnectionOpenedEvent} if this is the only connection
+	 * with the pending contact.
+	 *
+	 * @return True if this is the only connection with the pending contact,
+	 * false if it is redundant and should be closed
+	 */
+	boolean registerConnection(PendingContactId p);
+
+	/**
+	 * Unregisters a connection with the given pending contact. Broadcasts
+	 * {@link RendezvousConnectionClosedEvent}.
+	 */
+	void unregisterConnection(PendingContactId p, boolean success);
+}

bramble-api/src/main/java/org/briarproject/bramble/api/connection/InterruptibleConnection.java

@@ -0,0 +1,19 @@
+package org.briarproject.bramble.api.connection;
+
+import org.briarproject.nullsafety.NotNullByDefault;
+
+/**
+ * A duplex sync connection that can be closed by interrupting its outgoing
+ * sync session.
+ */
+@NotNullByDefault
+public interface InterruptibleConnection {
+
+	/**
+	 * Interrupts the connection's outgoing sync session. If the underlying
+	 * transport connection is alive and the remote peer is cooperative, this
+	 * should result in both sync sessions ending and the connection being
+	 * cleanly closed.
+	 */
+	void interruptOutgoingSession();
+}

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

@@ -0,0 +1,78 @@
+package org.briarproject.bramble.api.contact;
+
+import org.briarproject.bramble.api.crypto.PublicKey;
+import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.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 {
+
+	private final ContactId id;
+	private final Author author;
+	private final AuthorId localAuthorId;
+	@Nullable
+	private final String alias;
+	@Nullable
+	private final PublicKey handshakePublicKey;
+	private final boolean verified;
+
+	public Contact(ContactId id, Author author, AuthorId localAuthorId,
+			@Nullable String alias, @Nullable PublicKey handshakePublicKey,
+			boolean verified) {
+		if (alias != null) {
+			int aliasLength = toUtf8(alias).length;
+			if (aliasLength == 0 || aliasLength > MAX_AUTHOR_NAME_LENGTH)
+				throw new IllegalArgumentException();
+		}
+		this.id = id;
+		this.author = author;
+		this.localAuthorId = localAuthorId;
+		this.alias = alias;
+		this.handshakePublicKey = handshakePublicKey;
+		this.verified = verified;
+	}
+
+	public ContactId getId() {
+		return id;
+	}
+
+	public Author getAuthor() {
+		return author;
+	}
+
+	public AuthorId getLocalAuthorId() {
+		return localAuthorId;
+	}
+
+	@Nullable
+	public String getAlias() {
+		return alias;
+	}
+
+	@Nullable
+	public PublicKey getHandshakePublicKey() {
+		return handshakePublicKey;
+	}
+
+	public boolean isVerified() {
+		return verified;
+	}
+
+	@Override
+	public int hashCode() {
+		return id.hashCode();
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		return o instanceof Contact && id.equals(((Contact) o).id);
+	}
+}

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

@@ -0,0 +1,37 @@
+package org.briarproject.bramble.api.contact;
+
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.db.ContactExistsException;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.io.IOException;
+
+@NotNullByDefault
+public interface ContactExchangeManager {
+
+	/**
+	 * Exchanges contact information with a remote peer and adds the peer
+	 * as a contact.
+	 *
+	 * @param alice Whether the local peer takes the role of Alice
+	 * @return The newly added contact
+	 * @throws ContactExistsException If the contact already exists
+	 */
+	Contact exchangeContacts(DuplexTransportConnection conn,
+			SecretKey masterKey, boolean alice, boolean verified)
+			throws IOException, DbException;
+
+	/**
+	 * Exchanges contact information with a remote peer and adds the peer
+	 * as a contact, replacing the given pending contact.
+	 *
+	 * @param alice Whether the local peer takes the role of Alice
+	 * @return The newly added contact
+	 * @throws ContactExistsException If the contact already exists
+	 */
+	Contact exchangeContacts(PendingContactId p, DuplexTransportConnection conn,
+			SecretKey masterKey, boolean alice, boolean verified)
+			throws IOException, DbException;
+}

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

@@ -0,0 +1,35 @@
+package org.briarproject.bramble.api.contact;
+
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * Type-safe wrapper for an integer that uniquely identifies a contact within
+ * the scope of the local device.
+ */
+@Immutable
+@NotNullByDefault
+public class ContactId {
+
+	private final int id;
+
+	public ContactId(int id) {
+		this.id = id;
+	}
+
+	public int getInt() {
+		return id;
+	}
+
+	@Override
+	public int hashCode() {
+		return id;
+	}
+
+	@Override
+	public boolean equals(@Nullable Object o) {
+		return o instanceof ContactId && id == ((ContactId) o).id;
+	}
+}

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

@@ -0,0 +1,279 @@
+package org.briarproject.bramble.api.contact;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.Pair;
+import org.briarproject.bramble.api.UnsupportedVersionException;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.db.ContactExistsException;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.NoSuchContactException;
+import org.briarproject.bramble.api.db.PendingContactExistsException;
+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.lifecycle.LifecycleManager;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.security.GeneralSecurityException;
+import java.util.Collection;
+
+import javax.annotation.Nullable;
+
+@NotNullByDefault
+public interface ContactManager {
+
+	/**
+	 * Registers a hook to be called whenever a contact is added or removed.
+	 * This method should be called before
+	 * {@link LifecycleManager#startServices(SecretKey)}.
+	 */
+	void registerContactHook(ContactHook hook);
+
+	/**
+	 * Stores a contact associated with the given local and remote pseudonyms,
+	 * derives and stores rotation mode transport keys for each transport, and
+	 * returns an ID for the contact.
+	 *
+	 * @param rootKey The root key for a set of rotation mode transport keys
+	 * @param timestamp The timestamp for deriving rotation mode transport
+	 * keys from the root key
+	 * @param alice True if the local party is Alice
+	 * @param verified True if the contact's identity has been verified, which
+	 * is true if the contact was added in person or false if the contact was
+	 * introduced or added remotely
+	 * @param active True if the rotation mode transport keys can be used for
+	 * outgoing streams
+	 */
+	ContactId addContact(Transaction txn, Author remote, AuthorId local,
+			SecretKey rootKey, long timestamp, boolean alice, boolean verified,
+			boolean active) throws DbException;
+
+	/**
+	 * Stores a contact associated with the given local and remote pseudonyms,
+	 * replacing the given pending contact, derives and stores handshake mode
+	 * and rotation mode transport keys for each transport, and returns an ID
+	 * for the contact.
+	 *
+	 * @param rootKey The root key for a set of rotation mode transport keys
+	 * @param timestamp The timestamp for deriving rotation mode transport
+	 * keys from the root key
+	 * @param alice True if the local party is Alice
+	 * @param verified True if the contact's identity has been verified, which
+	 * is true if the contact was added in person or false if the contact was
+	 * introduced or added remotely
+	 * @param active True if the rotation mode transport keys can be used for
+	 * outgoing streams
+	 * @throws GeneralSecurityException If the pending contact's handshake
+	 * public key is invalid
+	 */
+	ContactId addContact(Transaction txn, PendingContactId p, Author remote,
+			AuthorId local, SecretKey rootKey, long timestamp, boolean alice,
+			boolean verified, boolean active)
+			throws DbException, GeneralSecurityException;
+
+	/**
+	 * Stores a contact associated with the given local and remote pseudonyms
+	 * and returns an ID for the contact.
+	 *
+	 * @param verified True if the contact's identity has been verified, which
+	 * is true if the contact was added in person or false if the contact was
+	 * introduced or added remotely
+	 */
+	ContactId addContact(Transaction txn, Author remote, AuthorId local,
+			boolean verified) throws DbException;
+
+	/**
+	 * Stores a contact associated with the given local and remote pseudonyms,
+	 * derives and stores rotation mode transport keys for each transport, and
+	 * returns an ID for the contact.
+	 *
+	 * @param rootKey The root key for a set of rotation mode transport keys
+	 * @param timestamp The timestamp for deriving rotation mode transport
+	 * keys from the root key
+	 * @param alice True if the local party is Alice
+	 * @param verified True if the contact's identity has been verified, which
+	 * is true if the contact was added in person or false if the contact was
+	 * introduced or added remotely
+	 * @param active True if the rotation mode transport keys can be used for
+	 * outgoing streams
+	 */
+	ContactId addContact(Author remote, AuthorId local, SecretKey rootKey,
+			long timestamp, boolean alice, boolean verified, boolean active)
+			throws DbException;
+
+	/**
+	 * Returns the handshake link that needs to be sent to a contact we want
+	 * to add.
+	 */
+	String getHandshakeLink() throws DbException;
+
+	/**
+	 * Returns the handshake link that needs to be sent to a contact we want
+	 * to add.
+	 */
+	String getHandshakeLink(Transaction txn) throws DbException;
+
+	/**
+	 * Creates a {@link PendingContact} from the given handshake link and
+	 * alias, adds it to the database and returns it.
+	 *
+	 * @param link The handshake link received from the pending contact
+	 * @param alias The alias the user has given this pending contact
+	 * @throws UnsupportedVersionException If the link uses a format version
+	 * that is not supported
+	 * @throws FormatException If the link is invalid
+	 * @throws GeneralSecurityException If the pending contact's handshake
+	 * public key is invalid
+	 * @throws ContactExistsException If a contact with the same handshake
+	 * public key already exists
+	 * @throws PendingContactExistsException If a pending contact with the same
+	 * handshake public key already exists
+	 */
+	PendingContact addPendingContact(Transaction txn, String link, String alias)
+			throws DbException, FormatException, GeneralSecurityException,
+			ContactExistsException, PendingContactExistsException;
+
+	/**
+	 * Creates a {@link PendingContact} from the given handshake link and
+	 * alias, adds it to the database and returns it.
+	 *
+	 * @param link The handshake link received from the pending contact
+	 * @param alias The alias the user has given this pending contact
+	 * @throws UnsupportedVersionException If the link uses a format version
+	 * that is not supported
+	 * @throws FormatException If the link is invalid
+	 * @throws GeneralSecurityException If the pending contact's handshake
+	 * public key is invalid
+	 * @throws ContactExistsException If a contact with the same handshake
+	 * public key already exists
+	 * @throws PendingContactExistsException If a pending contact with the same
+	 * handshake public key already exists
+	 */
+	PendingContact addPendingContact(String link, String alias)
+			throws DbException, FormatException, GeneralSecurityException,
+			ContactExistsException, PendingContactExistsException;
+
+	/**
+	 * Returns the pending contact with the given ID.
+	 */
+	PendingContact getPendingContact(Transaction txn, PendingContactId p)
+			throws DbException;
+
+	/**
+	 * Returns a list of {@link PendingContact PendingContacts} and their
+	 * {@link PendingContactState states}.
+	 */
+	Collection<Pair<PendingContact, PendingContactState>> getPendingContacts()
+			throws DbException;
+
+	/**
+	 * Returns a list of {@link PendingContact PendingContacts} and their
+	 * {@link PendingContactState states}.
+	 */
+	Collection<Pair<PendingContact, PendingContactState>> getPendingContacts(Transaction txn)
+			throws DbException;
+
+	/**
+	 * Removes a {@link PendingContact}.
+	 */
+	void removePendingContact(PendingContactId p) throws DbException;
+
+	/**
+	 * Removes a {@link PendingContact}.
+	 */
+	void removePendingContact(Transaction txn, PendingContactId p)
+			throws DbException;
+
+	/**
+	 * Returns the contact with the given ID.
+	 */
+	Contact getContact(ContactId c) throws DbException;
+
+	/**
+	 * Returns the contact with the given ID.
+	 */
+	Contact getContact(Transaction txn, ContactId c) throws DbException;
+
+	/**
+	 * Returns the contact with the given {@code remoteAuthorId}
+	 * that belongs to the local pseudonym with the given {@code localAuthorId}.
+	 *
+	 * @throws NoSuchContactException If the contact is not in the database
+	 */
+	Contact getContact(AuthorId remoteAuthorId, AuthorId localAuthorId)
+			throws DbException;
+
+	/**
+	 * Returns the contact with the given {@code remoteAuthorId}
+	 * that belongs to the local pseudonym with the given {@code localAuthorId}.
+	 *
+	 * @throws NoSuchContactException If the contact is not in the database
+	 */
+	Contact getContact(Transaction txn, AuthorId remoteAuthorId,
+			AuthorId localAuthorId) throws DbException;
+
+	/**
+	 * Returns all contacts.
+	 */
+	Collection<Contact> getContacts() throws DbException;
+
+	/**
+	 * Returns all contacts.
+	 */
+	Collection<Contact> getContacts(Transaction txn) throws DbException;
+
+	/**
+	 * Removes a contact and all associated state.
+	 */
+	void removeContact(ContactId c) throws DbException;
+
+	/**
+	 * Removes a contact and all associated state.
+	 */
+	void removeContact(Transaction txn, ContactId c) throws DbException;
+
+	/**
+	 * Sets an alias for the contact or unsets it if {@code alias} is null.
+	 */
+	void setContactAlias(Transaction txn, ContactId c, @Nullable String alias)
+			throws DbException;
+
+	/**
+	 * Sets an alias for the contact or unsets it if {@code alias} is null.
+	 */
+	void setContactAlias(ContactId c, @Nullable String alias)
+			throws DbException;
+
+	/**
+	 * Returns true if a contact with this {@code remoteAuthorId} belongs to
+	 * the local pseudonym with this {@code localAuthorId}.
+	 */
+	boolean contactExists(Transaction txn, AuthorId remoteAuthorId,
+			AuthorId localAuthorId) throws DbException;
+
+	/**
+	 * Returns true if a contact with this {@code remoteAuthorId} belongs to
+	 * the local pseudonym with this {@code localAuthorId}.
+	 */
+	boolean contactExists(AuthorId remoteAuthorId, AuthorId localAuthorId)
+			throws DbException;
+
+	interface ContactHook {
+
+		/**
+		 * Called when a contact is being added.
+		 *
+		 * @param txn A read-write transaction
+		 * @param c The contact that is being added
+		 */
+		void addingContact(Transaction txn, Contact c) throws DbException;
+
+		/**
+		 * Called when a contact is being removed
+		 *
+		 * @param txn A read-write transaction
+		 * @param c The contact that is being removed
+		 */
+		void removingContact(Transaction txn, Contact c) throws DbException;
+	}
+}

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

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

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

@@ -0,0 +1,45 @@
+package org.briarproject.bramble.api.contact;
+
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.transport.StreamWriter;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+@NotNullByDefault
+public interface HandshakeManager {
+
+	/**
+	 * Handshakes with the given pending contact. Returns an ephemeral master
+	 * key authenticated with both parties' handshake key pairs and a flag
+	 * indicating whether the local peer is Alice or Bob.
+	 *
+	 * @param in An incoming stream for the handshake, which must be secured in
+	 * handshake mode
+	 * @param out An outgoing stream for the handshake, which must be secured
+	 * in handshake mode
+	 */
+	HandshakeResult handshake(PendingContactId p, InputStream in,
+			StreamWriter out) throws DbException, IOException;
+
+	class HandshakeResult {
+
+		private final SecretKey masterKey;
+		private final boolean alice;
+
+		public HandshakeResult(SecretKey masterKey, boolean alice) {
+			this.masterKey = masterKey;
+			this.alice = alice;
+		}
+
+		public SecretKey getMasterKey() {
+			return masterKey;
+		}
+
+		public boolean isAlice() {
+			return alice;
+		}
+	}
+}

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

@@ -0,0 +1,51 @@
+package org.briarproject.bramble.api.contact;
+
+import org.briarproject.bramble.api.crypto.PublicKey;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+public class PendingContact {
+
+	private final PendingContactId id;
+	private final PublicKey publicKey;
+	private final String alias;
+	private final long timestamp;
+
+	public PendingContact(PendingContactId id, PublicKey publicKey,
+			String alias, long timestamp) {
+		this.id = id;
+		this.publicKey = publicKey;
+		this.alias = alias;
+		this.timestamp = timestamp;
+	}
+
+	public PendingContactId getId() {
+		return id;
+	}
+
+	public PublicKey getPublicKey() {
+		return publicKey;
+	}
+
+	public String getAlias() {
+		return alias;
+	}
+
+	public long getTimestamp() {
+		return timestamp;
+	}
+
+	@Override
+	public int hashCode() {
+		return id.hashCode();
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		return o instanceof PendingContact &&
+				id.equals(((PendingContact) o).id);
+	}
+}