Listen for wifi AP state changes.

We won't necessarily receive a connectivity change event when the wifi AP is enabled.

.gitignore

@@ -20,7 +20,6 @@ local.properties
 .idea/*
 !.idea/runConfigurations/
 !.idea/codeStyleSettings.xml
-!.idea/codeStyles
 .gradle
 build/
 *.iml

.gitlab-ci.yml

@@ -1,31 +1,29 @@
-image: briar/ci-image-android:latest
+image: registry.gitlab.com/fdroid/ci-images-base:latest
+
+cache:
+  paths:
+    - .gradle/wrapper
+    - .gradle/caches
+
+before_script:
+  - set -e
+  - export GRADLE_USER_HOME=$PWD/.gradle
+  # Accept the license for the Android build tools
+  - echo y | /opt/android-sdk/tools/bin/sdkmanager "build-tools;26.0.2"
+  # Download OpenJDK 6 so we can compile against its standard library
+  - JDK_FILE=openjdk-6-jre-headless_6b38-1.13.10-1~deb7u1_amd64.deb
+  - if [ ! -d openjdk ]
+  - then
+  - wget -q http://ftp.uk.debian.org/debian/pool/main/o/openjdk-6/$JDK_FILE
+  - dpkg-deb -x $JDK_FILE openjdk
+  - fi
+  - export JAVA_6_HOME=$PWD/openjdk/usr/lib/jvm/java-6-openjdk-amd64
 
 test:
-  before_script:
-    - set -e
-    - export GRADLE_USER_HOME=$PWD/.gradle
-
-  cache:
-    paths:
-      - .gradle/wrapper
-      - .gradle/caches
-
   script:
-    - ./gradlew --no-daemon animalSnifferMain animalSnifferTest
+    - ./gradlew test
-    - ./gradlew --no-daemon test
 
-  after_script:
+after_script:
-    # these file change every time but should not be cached
+    # this file changes every time but should not be cached
     - rm -f $GRADLE_USER_HOME/caches/modules-2/modules-2.lock
     - rm -fr $GRADLE_USER_HOME/caches/*/plugin-resolution/
-
-
-test_reproducible:
-  image: briar/reproducer:latest
-
-  script:
-    - cd /opt/briar-reproducer
-    - ./reproduce.py ${CI_COMMIT_REF_NAME}
-
-  only:
-    - tags

.idea/codeStyles/Project.xml

@@ -1,261 +0,0 @@
-<component name="ProjectCodeStyleConfiguration">
-  <code_scheme name="Project" version="173">
-    <option name="RIGHT_MARGIN" value="100" />
-    <AndroidXmlCodeStyleSettings>
-      <option name="USE_CUSTOM_SETTINGS" value="true" />
-    </AndroidXmlCodeStyleSettings>
-    <JavaCodeStyleSettings>
-      <option name="ANNOTATION_PARAMETER_WRAP" value="1" />
-      <option name="CLASS_COUNT_TO_USE_IMPORT_ON_DEMAND" value="99" />
-      <option name="NAMES_COUNT_TO_USE_IMPORT_ON_DEMAND" value="99" />
-      <option name="PACKAGES_TO_USE_IMPORT_ON_DEMAND">
-        <value />
-      </option>
-      <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>
-    <Objective-C-extensions>
-      <file>
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Import" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Macro" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Typedef" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Enum" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Constant" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Global" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Struct" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="FunctionPredecl" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Function" />
-      </file>
-      <class>
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Property" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Synthesize" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="InitMethod" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="StaticMethod" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="InstanceMethod" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="DeallocMethod" />
-      </class>
-      <extensions>
-        <pair source="cpp" header="h" fileNamingConvention="NONE" />
-        <pair source="c" header="h" fileNamingConvention="NONE" />
-      </extensions>
-    </Objective-C-extensions>
-    <XML>
-      <option name="XML_LEGACY_SETTINGS_IMPORTED" value="true" />
-    </XML>
-    <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">
-      <option name="FORCE_REARRANGE_MODE" value="1" />
-      <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_NAMESPACE>Namespace:</XML_NAMESPACE>
-                </AND>
-              </match>
-            </rule>
-          </section>
-          <section>
-            <rule>
-              <match>
-                <AND>
-                  <NAME>xmlns:.*</NAME>
-                  <XML_NAMESPACE>Namespace:</XML_NAMESPACE>
-                </AND>
-              </match>
-              <order>BY_NAME</order>
-            </rule>
-          </section>
-          <section>
-            <rule>
-              <match>
-                <AND>
-                  <NAME>.*:id</NAME>
-                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
-                </AND>
-              </match>
-            </rule>
-          </section>
-          <section>
-            <rule>
-              <match>
-                <AND>
-                  <NAME>.*:name</NAME>
-                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
-                </AND>
-              </match>
-            </rule>
-          </section>
-          <section>
-            <rule>
-              <match>
-                <AND>
-                  <NAME>name</NAME>
-                  <XML_NAMESPACE>^$</XML_NAMESPACE>
-                </AND>
-              </match>
-            </rule>
-          </section>
-          <section>
-            <rule>
-              <match>
-                <AND>
-                  <NAME>style</NAME>
-                  <XML_NAMESPACE>^$</XML_NAMESPACE>
-                </AND>
-              </match>
-            </rule>
-          </section>
-          <section>
-            <rule>
-              <match>
-                <AND>
-                  <NAME>.*</NAME>
-                  <XML_NAMESPACE>^$</XML_NAMESPACE>
-                </AND>
-              </match>
-              <order>BY_NAME</order>
-            </rule>
-          </section>
-          <section>
-            <rule>
-              <match>
-                <AND>
-                  <NAME>.*:layout_width</NAME>
-                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
-                </AND>
-              </match>
-            </rule>
-          </section>
-          <section>
-            <rule>
-              <match>
-                <AND>
-                  <NAME>.*:layout_height</NAME>
-                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
-                </AND>
-              </match>
-            </rule>
-          </section>
-          <section>
-            <rule>
-              <match>
-                <AND>
-                  <NAME>.*:layout_.*</NAME>
-                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
-                </AND>
-              </match>
-              <order>BY_NAME</order>
-            </rule>
-          </section>
-          <section>
-            <rule>
-              <match>
-                <AND>
-                  <NAME>.*:width</NAME>
-                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
-                </AND>
-              </match>
-              <order>BY_NAME</order>
-            </rule>
-          </section>
-          <section>
-            <rule>
-              <match>
-                <AND>
-                  <NAME>.*:height</NAME>
-                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
-                </AND>
-              </match>
-              <order>BY_NAME</order>
-            </rule>
-          </section>
-          <section>
-            <rule>
-              <match>
-                <AND>
-                  <NAME>.*</NAME>
-                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
-                </AND>
-              </match>
-              <order>BY_NAME</order>
-            </rule>
-          </section>
-          <section>
-            <rule>
-              <match>
-                <AND>
-                  <NAME>.*</NAME>
-                  <XML_NAMESPACE>.*</XML_NAMESPACE>
-                </AND>
-              </match>
-              <order>BY_NAME</order>
-            </rule>
-          </section>
-        </rules>
-      </arrangement>
-    </codeStyleSettings>
-  </code_scheme>
-</component>

.idea/codeStyles/codeStyleConfig.xml

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

bramble-android/build.gradle

@@ -1,15 +1,19 @@
+import de.undercouch.gradle.tasks.download.Download
+import de.undercouch.gradle.tasks.download.Verify
+
 apply plugin: 'com.android.library'
 apply plugin: 'witness'
+apply plugin: 'de.undercouch.download'
 
 android {
 	compileSdkVersion 27
-	buildToolsVersion '27.0.3'
+	buildToolsVersion '26.0.2'
 
 	defaultConfig {
 		minSdkVersion 14
 		targetSdkVersion 26
-		versionCode 10008
+		versionCode 1700
-		versionName "1.0.8"
+		versionName "0.17.0"
 		consumerProguardFiles 'proguard-rules.txt'
 	}
 
@@ -19,14 +23,9 @@ android {
 	}
 }
 
-configurations {
-	tor
-}
-
 dependencies {
 	implementation project(path: ':bramble-core', configuration: 'default')
-	implementation 'org.briarproject:jtorctl:0.3'
+	implementation fileTree(dir: 'libs', include: '*.jar')
-	tor 'org.briarproject:tor-android:0.2.9.15@zip'
 
 	annotationProcessor 'com.google.dagger:dagger-compiler:2.0.2'
 
@@ -35,87 +34,63 @@ dependencies {
 
 dependencyVerification {
 	verify = [
-			'com.android.tools.analytics-library:protos:26.1.2:protos-26.1.2.jar:52672a0b42b572a06aecc3535d5068eb46c0e15d129b9f1085d3c16a1da5cdbb',
+			'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
-			'com.android.tools.analytics-library:shared:26.1.2:shared-26.1.2.jar:5c7e0eda18c6f87feeb83628c707e8aaa3298b41fb72e38efe31ad1675f9e8e9',
-			'com.android.tools.analytics-library:tracker:26.1.2:tracker-26.1.2.jar:06f97aa0adf44ffb06f8681c6a79d9be153a08f61d21eddc42b8d3db96df4282',
-			'com.android.tools.build:apksig:3.1.2:apksig-3.1.2.jar:40696a4559124d1d57873d208857eee059d48859239d569c7d18374ac644a8be',
-			'com.android.tools.build:builder-model:3.1.2:builder-model-3.1.2.jar:d49bfa2a135c9562b6ca7aa4342036cfa1582c7074c2d1d93d1dae8b3a134e17',
-			'com.android.tools.build:builder-test-api:3.1.2:builder-test-api-3.1.2.jar:dfe2a50b740d41b11189101062434d4283d18647e89a492ad51710c719363e9f',
-			'com.android.tools.build:builder:3.1.2:builder-3.1.2.jar:b60f825a42e2efe8433619fbc759f3d9effecab718279048d36881188ceb1d14',
-			'com.android.tools.build:gradle-api:3.1.2:gradle-api-3.1.2.jar:e58bcc5b893e4583ab0f5c8ef89c4dbcce202b405a9d7fcc116d21e5357d4893',
-			'com.android.tools.build:manifest-merger:26.1.2:manifest-merger-26.1.2.jar:9c61c27ea5266573107b954acf1216d398f4d7e7ae6fad6409d6b2b767eb091c',
-			'com.android.tools.ddms:ddmlib:26.1.2:ddmlib-26.1.2.jar:18a2a5fbef36882f07d03c2b9e59eba05cf8248177bf5cbff736e4b582804c44',
-			'com.android.tools.external.com-intellij:intellij-core:26.1.2:intellij-core-26.1.2.jar:37c5acf279f1ae3e85b1a5be3c9f15f43bde7b08f978eefefffb9c4035760c52',
-			'com.android.tools.external.com-intellij:kotlin-compiler:26.1.2:kotlin-compiler-26.1.2.jar:152df0bee7580326c77316b669a9d96e3b09efb1d45f545dce4147271b0b8944',
-			'com.android.tools.external.org-jetbrains:uast:26.1.2:uast-26.1.2.jar:02d39582206d3f5fc0a6cb18bfd9e8b9f9c1acb805ec6dac08b4e3a56849d279',
-			'com.android.tools.layoutlib:layoutlib-api:26.1.2:layoutlib-api-26.1.2.jar:20220039fcc7d799f928153beff862e704457c0f55ab44258f3745ebeb662b4f',
-			'com.android.tools.lint:lint-api:26.1.2:lint-api-26.1.2.jar:e1d5b62b870a7c566e9877a6b96b27784a4d713f8caa07fdcb4705d47a40a1d9',
-			'com.android.tools.lint:lint-checks:26.1.2:lint-checks-26.1.2.jar:211e2afd58504372385d71b1e5be982c2b5121ab6fee1c04ddabeb75a8729e07',
-			'com.android.tools.lint:lint-gradle-api:26.1.2:lint-gradle-api-26.1.2.jar:71284f2a8b03c3e55c94511c9eb36f8184fbb85324325fc6b78abf5183f03d90',
-			'com.android.tools.lint:lint-gradle:26.1.2:lint-gradle-26.1.2.jar:855f0c82b7fc690df1b7319c0774f7517f7f8f5dd4eee1f6077dcf50e07c6240',
-			'com.android.tools.lint:lint-kotlin:26.1.2:lint-kotlin-26.1.2.jar:1e591f70bcbbc11569720a9bbcca2bc1f3d4f789f01f40f642848d920643d484',
-			'com.android.tools.lint:lint:26.1.2:lint-26.1.2.jar:93736c62e9f1976998c2b4aa716aea0734cdb162d05502f4af7292654aedb182',
-			'com.android.tools:annotations:26.1.2:annotations-26.1.2.jar:72773dcaf5c4ccca828e3c8467f1b78a8a00b3cc5f8ad1aab88fcf9379928018',
-			'com.android.tools:common:26.1.2:common-26.1.2.jar:ea4320f0c17dcbc4491896bb705c4d25ec08bd62ef02ab0579fe154e75e788e6',
-			'com.android.tools:dvlib:26.1.2:dvlib-26.1.2.jar:1187aa4fb666595c96c4deb6bc0e0f4b7e396bde9f6243330b49a232946130ea',
-			'com.android.tools:repository:26.1.2:repository-26.1.2.jar:8b86e512ad6d32bd76989451eefe2b271f5efce6d4d65ecb173afaf14606e01a',
-			'com.android.tools:sdk-common:26.1.2:sdk-common-26.1.2.jar:23584720a60a21cdcb5b1ec10269e3013789d6805d153cc696c39ec7ce251896',
-			'com.android.tools:sdklib:26.1.2:sdklib-26.1.2.jar:d3870fafc59ab8efa70d3f9649f40ee299c8ec5b58377b06e8853d7272a5bf4e',
-			'com.google.code.findbugs:jsr305:1.3.9:jsr305-1.3.9.jar:905721a0eea90a81534abb7ee6ef4ea2e5e645fa1def0a5cd88402df1b46c9ed',
-			'com.google.code.gson:gson:2.7:gson-2.7.jar:2d43eb5ea9e133d2ee2405cc14f5ee08951b8361302fdd93494a3a997b508d32',
 			'com.google.dagger:dagger-compiler:2.0.2:dagger-compiler-2.0.2.jar:b74bc9de063dd4c6400b232231f2ef5056145b8fbecbf5382012007dd1c071b3',
 			'com.google.dagger:dagger-producers:2.0-beta:dagger-producers-2.0-beta.jar:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
 			'com.google.dagger:dagger:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
-			'com.google.errorprone:error_prone_annotations:2.0.18:error_prone_annotations-2.0.18.jar:cb4cfad870bf563a07199f3ebea5763f0dec440fcda0b318640b1feaa788656b',
 			'com.google.guava:guava:18.0:guava-18.0.jar:d664fbfc03d2e5ce9cab2a44fb01f1d0bf9dfebeccc1a473b1f9ea31f79f6f99',
-			'com.google.guava:guava:22.0:guava-22.0.jar:1158e94c7de4da480873f0b4ab4a1da14c0d23d4b1902cc94a58a6f0f9ab579e',
+			'com.h2database:h2:1.4.192:h2-1.4.192.jar:225b22e9857235c46c93861410b60b8c81c10dc8985f4faf188985ba5445126c',
-			'com.google.j2objc:j2objc-annotations:1.1:j2objc-annotations-1.1.jar:40ceb7157feb263949e0f503fe5f71689333a621021aa20ce0d0acee3badaa0f',
+			'com.madgag.spongycastle:core:1.58.0.0:core-1.58.0.0.jar:199617dd5698c5a9312b898c0a4cec7ce9dd8649d07f65d91629f58229d72728',
-			'com.google.jimfs:jimfs:1.1:jimfs-1.1.jar:c4828e28d7c0a930af9387510b3bada7daa5c04d7c25a75c7b8b081f1c257ddd',
-			'com.google.protobuf:protobuf-java:3.4.0:protobuf-java-3.4.0.jar:dce7e66b32456a1b1198da0caff3a8acb71548658391e798c79369241e6490a4',
-			'com.googlecode.json-simple:json-simple:1.1:json-simple-1.1.jar:2d9484f4c649f708f47f9a479465fc729770ee65617dca3011836602264f6439',
-			'com.squareup:javawriter:2.5.0:javawriter-2.5.0.jar:fcfb09fb0ea0aa97d3cfe7ea792398081348e468f126b3603cb3803f240197f0',
-			'com.sun.activation:javax.activation:1.2.0:javax.activation-1.2.0.jar:993302b16cd7056f21e779cc577d175a810bb4900ef73cd8fbf2b50f928ba9ce',
-			'com.sun.istack:istack-commons-runtime:2.21:istack-commons-runtime-2.21.jar:c33e67a0807095f02a0e2da139412dd7c4f9cc1a4c054b3e434f96831ba950f4',
-			'com.sun.xml.fastinfoset:FastInfoset:1.2.13:FastInfoset-1.2.13.jar:27a77db909f3c2833c0b1a37c55af1db06045118ad2eed96ce567b6632bce038',
-			'commons-codec:commons-codec:1.6:commons-codec-1.6.jar:54b34e941b8e1414bd3e40d736efd3481772dc26db3296f6aa45cec9f6203d86',
-			'commons-logging:commons-logging:1.1.1:commons-logging-1.1.1.jar:ce6f913cad1f0db3aad70186d65c5bc7ffcc9a99e3fe8e0b137312819f7c362f',
-			'it.unimi.dsi:fastutil:7.2.0:fastutil-7.2.0.jar:74fa208043740642f7e6eb09faba15965218ad2f50ce3020efb100136e4b591c',
 			'javax.annotation:jsr250-api:1.0:jsr250-api-1.0.jar:a1a922d0d9b6d183ed3800dfac01d1e1eb159f0e8c6f94736931c1def54a941f',
 			'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
-			'javax.xml.bind:jaxb-api:2.2.12-b140109.1041:jaxb-api-2.2.12-b140109.1041.jar:b5e60cd8b7b5ff01ce4a74c5dd008f4fbd14ced3495d0b47b85cfedc182211f2',
+			'net.i2p.crypto:eddsa:0.2.0:eddsa-0.2.0.jar:a7cb1b85c16e2f0730b9204106929a1d9aaae1df728adc7041a8b8b605692140',
-			'net.sf.jopt-simple:jopt-simple:4.9:jopt-simple-4.9.jar:26c5856e954b5f864db76f13b86919b59c6eecf9fd930b96baa8884626baf2f5',
+			'org.bitlet:weupnp:0.1.4:weupnp-0.1.4.jar:88df7e6504929d00bdb832863761385c68ab92af945b04f0770b126270a444fb',
-			'net.sf.kxml:kxml2:2.3.0:kxml2-2.3.0.jar:f264dd9f79a1fde10ce5ecc53221eff24be4c9331c830b7d52f2f08a7b633de2',
+			'org.jacoco:org.jacoco.agent:0.7.4.201502262128:org.jacoco.agent-0.7.4.201502262128-runtime.jar:e357a0f1d573c2f702a273992b1b6cb661734f66311854efb3778a888515c5b5',
-			'org.apache.commons:commons-compress:1.12:commons-compress-1.12.jar:2c1542faf343185b7cab9c3d55c8ae5471d6d095d3887a4adefdbdf2984dc0b6',
+			'org.jacoco:org.jacoco.agent:0.7.4.201502262128:org.jacoco.agent-0.7.4.201502262128.jar:47b4bec6df11a1118da3953da8b9fa1e7079d6fec857faa1a3cf912e53a6fd4e',
-			'org.apache.httpcomponents:httpclient:4.2.6:httpclient-4.2.6.jar:362e9324ee7c697e21279e20077b52737ddef3f1b2c1a7abe5ad34b465145550',
+			'org.jacoco:org.jacoco.ant:0.7.4.201502262128:org.jacoco.ant-0.7.4.201502262128.jar:013ce2a68ba57a3c59215ae0dec4df3498c078062a38c3b94c841fc14450f283',
-			'org.apache.httpcomponents:httpcore:4.2.5:httpcore-4.2.5.jar:e5e82da4cc66c8d917bbf743e3c0752efe8522735e7fc9dbddb65bccea81cfe9',
+			'org.jacoco:org.jacoco.core:0.7.4.201502262128:org.jacoco.core-0.7.4.201502262128.jar:ec4c74554312fac5116350164786f91b35c9e082fa4ea598bfa42b5db05d7abb',
-			'org.apache.httpcomponents:httpmime:4.1:httpmime-4.1.jar:31629566148e8a47688ae43b420abc3ecd783ed15b33bebc00824bf24c9b15aa',
+			'org.jacoco:org.jacoco.report:0.7.4.201502262128:org.jacoco.report-0.7.4.201502262128.jar:7a3554c605e088e7e323b1084656243f0444fa353e2f2dee1f1a4204eb64ff09',
-			'org.bouncycastle:bcpkix-jdk15on:1.56:bcpkix-jdk15on-1.56.jar:7043dee4e9e7175e93e0b36f45b1ec1ecb893c5f755667e8b916eb8dd201c6ca',
+			'org.ow2.asm:asm-debug-all:5.0.1:asm-debug-all-5.0.1.jar:4734de5b515a454b0096db6971fb068e5f70e6f10bbee2b3bd2fdfe5d978ed57',
-			'org.bouncycastle:bcprov-jdk15on:1.56:bcprov-jdk15on-1.56.jar:963e1ee14f808ffb99897d848ddcdb28fa91ddda867eb18d303e82728f878349',
-			'org.briarproject:jtorctl:0.3:jtorctl-0.3.jar:f2939238a097898998432effe93b0334d97a787972ab3a91a8973a1d309fc864',
-			'org.briarproject:tor-android:0.2.9.15:tor-android-0.2.9.15.zip:34a6474ee219ffa52e0f3393e917dda6ed03d320b02247d4fa5075aa4094ee6d',
-			'org.codehaus.groovy:groovy-all:2.4.12:groovy-all-2.4.12.jar:6a56af4bd48903d56bec62821876cadefafd007360cc6bd0d8f7aa8d72b38be4',
-			'org.codehaus.mojo:animal-sniffer-annotations:1.14:animal-sniffer-annotations-1.14.jar:2068320bd6bad744c3673ab048f67e30bef8f518996fa380033556600669905d',
-			'org.glassfish.jaxb:jaxb-core:2.2.11:jaxb-core-2.2.11.jar:37bcaee8ebb04362c8352a5bf6221b86967ecdab5164c696b10b9a2bb587b2aa',
-			'org.glassfish.jaxb:jaxb-runtime:2.2.11:jaxb-runtime-2.2.11.jar:a874f2351cfba8e2946be3002d10c18a6da8f21b52ba2acf52f2b85d5520ed70',
-			'org.glassfish.jaxb:txw2:2.2.11:txw2-2.2.11.jar:272a3ccad45a4511351920cd2a8633c53cab8d5220c7a92954da5526bb5eafea',
-			'org.jetbrains.kotlin:kotlin-reflect:1.2.0:kotlin-reflect-1.2.0.jar:4f48a872bad6e4d9c053f4ad610d11e4012ad7e58dc19a03dd5eb811f36069dd',
-			'org.jetbrains.kotlin:kotlin-stdlib-jre7:1.2.0:kotlin-stdlib-jre7-1.2.0.jar:c7a20fb951d437797afe8980aff6c1e5a03f310c661ba58ba1d4fa90cb0f2926',
-			'org.jetbrains.kotlin:kotlin-stdlib-jre8:1.2.0:kotlin-stdlib-jre8-1.2.0.jar:633524eee6ef1941f7cb1dab7ee3927b0a221ceee9047aeb5515f4cbb990c82a',
-			'org.jetbrains.kotlin:kotlin-stdlib:1.2.0:kotlin-stdlib-1.2.0.jar:05cfd9f5ac0b41910703a8925f7211a495909b27a2ffdd1c5106f1689aeafcd4',
-			'org.jetbrains.trove4j:trove4j:20160824:trove4j-20160824.jar:1917871c8deb468307a584680c87a44572f5a8b0b98c6d397fc0f5f86596dbe7',
-			'org.jetbrains:annotations:13.0:annotations-13.0.jar:ace2a10dc8e2d5fd34925ecac03e4988b2c0f851650c94b8cef49ba1bd111478',
-			'org.jvnet.staxex:stax-ex:1.7.7:stax-ex-1.7.7.jar:a31ff7d77163c0deb09e7fee59ad35ae44c2cee2cc8552a116ccd1583d813fb4',
-			'org.ow2.asm:asm-analysis:5.1:asm-analysis-5.1.jar:a34658f5c5de4b573eef21131cc32cc25f7b66407944f312b28ec2e56abb1fa9',
-			'org.ow2.asm:asm-commons:5.1:asm-commons-5.1.jar:97b3786e1f55e74bddf8ad102bf50e33bbcbc1f6b7fd7b36f0bbbb25cd4981be',
-			'org.ow2.asm:asm-tree:5.1:asm-tree-5.1.jar:c0de2bbc4cb8297419659813ecd4ed1d077ed1dd5c1f5544cc5143e493e84c10',
-			'org.ow2.asm:asm-util:5.1:asm-util-5.1.jar:ee032c39ae5e3cd099148fbba9a2124f9ed613e5cb93e03ee0fa8808ce364040',
-			'org.ow2.asm:asm:5.1:asm-5.1.jar:d2da399a9967c69f0a21739256fa79d284222c223082cacadc17372244764b54',
 	]
 }
 
-project.afterEvaluate {
+ext.torBinaryDir = 'src/main/res/raw'
-	copy {
+ext.torVersion = '0.2.9.14'
-		from configurations.tor.collect { zipTree(it) }
+ext.geoipVersion = '2017-11-06'
-		into 'src/main/res/raw'
+ext.torDownloadUrl = 'https://briarproject.org/build/'
+
+def torBinaries = [
+		"tor_arm"    : '1710ea6c47b7f4c1a88bdf4858c7893837635db10e8866854eed8d61629f50e8',
+		"tor_arm_pie": '974e6949507db8fa2ea45231817c2c3677ed4ccf5488a2252317d744b0be1917',
+		"tor_x86"    : '3a5e45b3f051fcda9353b098b7086e762ffe7ba9242f7d7c8bf6523faaa8b1e9',
+		"tor_x86_pie": 'd1d96d8ce1a4b68accf04850185780d10cd5563d3552f7e1f040f8ca32cb4e51',
+		"geoip"      : '8239b98374493529a29096e45fc5877d4d6fdad0146ad8380b291f90d61484ea'
+]
+
+def downloadBinary(name) {
+	return tasks.create("downloadBinary${name}", Download) {
+		src "${torDownloadUrl}${name}.zip"
+				.replace('tor_', "tor-${torVersion}-")
+				.replace('geoip', "geoip-${geoipVersion}")
+				.replaceAll('_', '-')
+		dest "${torBinaryDir}/${name}.zip"
+		onlyIfNewer true
+	}
+}
+
+def verifyBinary(name, chksum) {
+	return tasks.create([
+			name     : "verifyBinary${name}",
+			type     : Verify,
+			dependsOn: downloadBinary(name)]) {
+		src "${torBinaryDir}/${name}.zip"
+		algorithm 'SHA-256'
+		checksum chksum
+	}
+}
+
+project.afterEvaluate {
+	torBinaries.every { key, value ->
+		preBuild.dependsOn.add(verifyBinary(key, value))
 	}
 }

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

@@ -1,10 +1,12 @@
 package org.briarproject.bramble;
 
+import org.briarproject.bramble.plugin.AndroidPluginModule;
 import org.briarproject.bramble.system.AndroidSystemModule;
 
 import dagger.Module;
 
 @Module(includes = {
+		AndroidPluginModule.class,
 		AndroidSystemModule.class
 })
 public class BrambleAndroidModule {

bramble-android/src/main/java/org/briarproject/bramble/plugin/AndroidPluginModule.java

@@ -0,0 +1,69 @@
+package org.briarproject.bramble.plugin;
+
+import android.app.Application;
+import android.content.Context;
+
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.BackoffFactory;
+import org.briarproject.bramble.api.plugin.PluginConfig;
+import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
+import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
+import org.briarproject.bramble.api.reporting.DevReporter;
+import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.bramble.api.system.LocationUtils;
+import org.briarproject.bramble.api.system.Scheduler;
+import org.briarproject.bramble.plugin.bluetooth.AndroidBluetoothPluginFactory;
+import org.briarproject.bramble.plugin.tcp.AndroidLanTcpPluginFactory;
+import org.briarproject.bramble.plugin.tor.TorPluginFactory;
+
+import java.security.SecureRandom;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ScheduledExecutorService;
+
+import javax.net.SocketFactory;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class AndroidPluginModule {
+
+	@Provides
+	PluginConfig providePluginConfig(@IoExecutor Executor ioExecutor,
+			@Scheduler ScheduledExecutorService scheduler,
+			AndroidExecutor androidExecutor, SecureRandom random,
+			SocketFactory torSocketFactory, BackoffFactory backoffFactory,
+			Application app, LocationUtils locationUtils, DevReporter reporter,
+			EventBus eventBus) {
+		Context appContext = app.getApplicationContext();
+		DuplexPluginFactory bluetooth =
+				new AndroidBluetoothPluginFactory(ioExecutor, androidExecutor,
+						appContext, random, eventBus, backoffFactory);
+		DuplexPluginFactory tor = new TorPluginFactory(ioExecutor, scheduler,
+				appContext, locationUtils, reporter, eventBus,
+				torSocketFactory, backoffFactory);
+		DuplexPluginFactory lan = new AndroidLanTcpPluginFactory(ioExecutor,
+				backoffFactory, appContext);
+		Collection<DuplexPluginFactory> duplex =
+				Arrays.asList(bluetooth, tor, lan);
+		@NotNullByDefault
+		PluginConfig pluginConfig = new PluginConfig() {
+
+			@Override
+			public Collection<DuplexPluginFactory> getDuplexFactories() {
+				return duplex;
+			}
+
+			@Override
+			public Collection<SimplexPluginFactory> getSimplexFactories() {
+				return Collections.emptyList();
+			}
+		};
+		return pluginConfig;
+	}
+}

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

@@ -55,12 +55,10 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 	// Non-null if the plugin started successfully
 	private volatile BluetoothAdapter adapter = null;
 
-	AndroidBluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
+	AndroidBluetoothPlugin(Executor ioExecutor, AndroidExecutor androidExecutor,
-			Executor ioExecutor, AndroidExecutor androidExecutor,
 			Context appContext, SecureRandom secureRandom, Backoff backoff,
 			DuplexPluginCallback callback, int maxLatency) {
-		super(connectionLimiter, ioExecutor, secureRandom, backoff, callback,
+		super(ioExecutor, secureRandom, backoff, callback, maxLatency);
-				maxLatency);
 		this.androidExecutor = androidExecutor;
 		this.appContext = appContext;
 	}
@@ -156,8 +154,7 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 	}
 
 	private DuplexTransportConnection wrapSocket(BluetoothSocket s) {
-		return new AndroidBluetoothTransportConnection(this,
+		return new AndroidBluetoothTransportConnection(this, s);
-				connectionLimiter, s);
 	}
 
 	@Override

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

@@ -59,13 +59,11 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 
 	@Override
 	public DuplexPlugin createPlugin(DuplexPluginCallback callback) {
-		BluetoothConnectionLimiter connectionLimiter =
-				new BluetoothConnectionLimiterImpl();
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		AndroidBluetoothPlugin plugin = new AndroidBluetoothPlugin(
+		AndroidBluetoothPlugin plugin = new AndroidBluetoothPlugin(ioExecutor,
-				connectionLimiter, ioExecutor, androidExecutor, appContext,
+				androidExecutor, appContext, secureRandom, backoff, callback,
-				secureRandom, backoff, callback, MAX_LATENCY);
+				MAX_LATENCY);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

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

@@ -14,14 +14,10 @@ import java.io.OutputStream;
 class AndroidBluetoothTransportConnection
 		extends AbstractDuplexTransportConnection {
 
-	private final BluetoothConnectionLimiter connectionManager;
 	private final BluetoothSocket socket;
 
-	AndroidBluetoothTransportConnection(Plugin plugin,
+	AndroidBluetoothTransportConnection(Plugin plugin, BluetoothSocket socket) {
-			BluetoothConnectionLimiter connectionManager,
-			BluetoothSocket socket) {
 		super(plugin);
-		this.connectionManager = connectionManager;
 		this.socket = socket;
 	}
 
@@ -37,10 +33,6 @@ class AndroidBluetoothTransportConnection
 
 	@Override
 	protected void closeConnection(boolean exception) throws IOException {
-		try {
+		socket.close();
-			socket.close();
-		} finally {
-			connectionManager.connectionClosed(this);
-		}
 	}
 }

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

@@ -5,84 +5,43 @@ import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.net.ConnectivityManager;
-import android.net.Network;
 import android.net.NetworkInfo;
-import android.net.wifi.WifiInfo;
+import android.os.Bundle;
-import android.net.wifi.WifiManager;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
 
-import java.io.IOException;
-import java.net.InetAddress;
-import java.net.Socket;
-import java.net.UnknownHostException;
-import java.util.Collection;
 import java.util.concurrent.Executor;
-import java.util.concurrent.ScheduledExecutorService;
 import java.util.logging.Logger;
 
 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.ConnectivityManager.CONNECTIVITY_ACTION;
 import static android.net.ConnectivityManager.TYPE_WIFI;
 import static android.net.wifi.WifiManager.EXTRA_WIFI_STATE;
-import static android.os.Build.VERSION.SDK_INT;
+import static java.util.logging.Level.INFO;
-import static java.util.Collections.emptyList;
+import static org.briarproject.bramble.util.AndroidUtils.logNetworkState;
-import static java.util.Collections.singletonList;
-import static java.util.concurrent.TimeUnit.SECONDS;
 
 @NotNullByDefault
 class AndroidLanTcpPlugin extends LanTcpPlugin {
 
-	// See android.net.wifi.WifiManager
+	private static final String WIFI_AP_STATE_ACTION =
-	private static final String WIFI_AP_STATE_CHANGED_ACTION =
 			"android.net.wifi.WIFI_AP_STATE_CHANGED";
-	private static final int WIFI_AP_STATE_ENABLED = 13;
-
-	private static final byte[] WIFI_AP_ADDRESS_BYTES =
-			{(byte) 192, (byte) 168, 43, 1};
-	private static final InetAddress WIFI_AP_ADDRESS;
-
 	private static final Logger LOG =
 			Logger.getLogger(AndroidLanTcpPlugin.class.getName());
 
-	static {
-		try {
-			WIFI_AP_ADDRESS = InetAddress.getByAddress(WIFI_AP_ADDRESS_BYTES);
-		} catch (UnknownHostException e) {
-			// Should only be thrown if the address has an illegal length
-			throw new AssertionError(e);
-		}
-	}
-
-	private final ScheduledExecutorService scheduler;
 	private final Context appContext;
-	private final ConnectivityManager connectivityManager;
-	@Nullable
-	private final WifiManager wifiManager;
 
 	@Nullable
 	private volatile BroadcastReceiver networkStateReceiver = null;
-	private volatile SocketFactory socketFactory;
 
-	AndroidLanTcpPlugin(Executor ioExecutor, ScheduledExecutorService scheduler,
+	AndroidLanTcpPlugin(Executor ioExecutor, Backoff backoff,
-			Backoff backoff, Context appContext, DuplexPluginCallback callback,
+			Context appContext, DuplexPluginCallback callback, int maxLatency,
-			int maxLatency, int maxIdleTime) {
+			int maxIdleTime) {
 		super(ioExecutor, backoff, callback, maxLatency, maxIdleTime);
-		this.scheduler = scheduler;
 		this.appContext = appContext;
-		ConnectivityManager connectivityManager = (ConnectivityManager)
-				appContext.getSystemService(CONNECTIVITY_SERVICE);
-		if (connectivityManager == null) throw new AssertionError();
-		this.connectivityManager = connectivityManager;
-		wifiManager = (WifiManager) appContext.getApplicationContext()
-				.getSystemService(WIFI_SERVICE);
-		socketFactory = SocketFactory.getDefault();
 	}
 
 	@Override
@@ -93,8 +52,9 @@ class AndroidLanTcpPlugin extends LanTcpPlugin {
 		networkStateReceiver = new NetworkStateReceiver();
 		IntentFilter filter = new IntentFilter();
 		filter.addAction(CONNECTIVITY_ACTION);
-		filter.addAction(WIFI_AP_STATE_CHANGED_ACTION);
+		filter.addAction(WIFI_AP_STATE_ACTION);
 		appContext.registerReceiver(networkStateReceiver, filter);
+		if (LOG.isLoggable(INFO)) logNetworkState(appContext, LOG);
 	}
 
 	@Override
@@ -105,92 +65,38 @@ class AndroidLanTcpPlugin extends LanTcpPlugin {
 		tryToClose(socket);
 	}
 
-	@Override
-	protected Socket createSocket() throws IOException {
-		return socketFactory.createSocket();
-	}
-
-	@Override
-	protected Collection<InetAddress> getLocalIpAddresses() {
-		// If the device doesn't have wifi, don't open any sockets
-		if (wifiManager == null) return emptyList();
-		// If we're connected to a wifi network, use that network
-		WifiInfo info = wifiManager.getConnectionInfo();
-		if (info != null && info.getIpAddress() != 0)
-			return singletonList(intToInetAddress(info.getIpAddress()));
-		// If we're running an access point, return its address
-		if (super.getLocalIpAddresses().contains(WIFI_AP_ADDRESS))
-				return singletonList(WIFI_AP_ADDRESS);
-		// No suitable addresses
-		return emptyList();
-	}
-
-	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() {
-		if (SDK_INT < 21) return SocketFactory.getDefault();
-		for (Network net : connectivityManager.getAllNetworks()) {
-			NetworkInfo info = connectivityManager.getNetworkInfo(net);
-			if (info != null && info.getType() == TYPE_WIFI)
-				return net.getSocketFactory();
-		}
-		LOG.warning("Could not find suitable socket factory");
-		return SocketFactory.getDefault();
-	}
-
 	private class NetworkStateReceiver extends BroadcastReceiver {
 
 		@Override
 		public void onReceive(Context ctx, Intent i) {
 			if (!running) return;
-			if (isApEnabledEvent(i)) {
+			if (LOG.isLoggable(INFO)) {
-				// The state change may be broadcast before the AP address is
+				if (CONNECTIVITY_ACTION.equals(i.getAction())) {
-				// visible, so delay handling the event
+					LOG.info("Connectivity change");
-				scheduler.schedule(this::handleConnectivityChange, 1, SECONDS);
+					Bundle extras = i.getExtras();
-			} else {
+					if (extras != null) {
-				handleConnectivityChange();
+						LOG.info("Extras:");
+						for (String key : extras.keySet())
+							LOG.info("\t" + key + ": " + extras.get(key));
+					}
+				} else if (WIFI_AP_STATE_ACTION.equals(i.getAction())) {
+					int state = i.getIntExtra(EXTRA_WIFI_STATE, 0);
+					if (state == 13) LOG.info("Wifi AP enabled");
+					else LOG.info("Wifi AP state " + state);
+				}
+				logNetworkState(appContext, LOG);
 			}
-		}
+			Object o = ctx.getSystemService(CONNECTIVITY_SERVICE);
-
+			ConnectivityManager cm = (ConnectivityManager) o;
-		private void handleConnectivityChange() {
+			NetworkInfo net = cm.getActiveNetworkInfo();
-			if (!running) return;
+			if (net != null && net.getType() == TYPE_WIFI
-			Collection<InetAddress> addrs = getLocalIpAddresses();
+					&& net.isConnected()) {
-			if (addrs.contains(WIFI_AP_ADDRESS)) {
+				LOG.info("Connected to Wi-Fi");
-				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();
 				if (socket == null || socket.isClosed()) bind();
-			} else if (addrs.isEmpty()) {
+			} else {
-				LOG.info("Not connected to wifi");
+				LOG.info("Not connected to Wi-Fi");
-				socketFactory = SocketFactory.getDefault();
 				tryToClose(socket);
-			} else {
-				LOG.info("Connected to wifi");
-				socketFactory = getSocketFactory();
-				if (socket == null || socket.isClosed()) bind();
 			}
 		}
-
-		private boolean isApEnabledEvent(Intent i) {
-			return WIFI_AP_STATE_CHANGED_ACTION.equals(i.getAction()) &&
-					i.getIntExtra(EXTRA_WIFI_STATE, 0) == WIFI_AP_STATE_ENABLED;
-		}
 	}
 }

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

@@ -11,7 +11,6 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
 
 import java.util.concurrent.Executor;
-import java.util.concurrent.ScheduledExecutorService;
 
 import javax.annotation.concurrent.Immutable;
 
@@ -28,15 +27,12 @@ public class AndroidLanTcpPluginFactory implements DuplexPluginFactory {
 	private static final double BACKOFF_BASE = 1.2;
 
 	private final Executor ioExecutor;
-	private final ScheduledExecutorService scheduler;
 	private final BackoffFactory backoffFactory;
 	private final Context appContext;
 
 	public AndroidLanTcpPluginFactory(Executor ioExecutor,
-			ScheduledExecutorService scheduler, BackoffFactory backoffFactory,
+			BackoffFactory backoffFactory, Context appContext) {
-			Context appContext) {
 		this.ioExecutor = ioExecutor;
-		this.scheduler = scheduler;
 		this.backoffFactory = backoffFactory;
 		this.appContext = appContext;
 	}
@@ -55,7 +51,7 @@ public class AndroidLanTcpPluginFactory implements DuplexPluginFactory {
 	public DuplexPlugin createPlugin(DuplexPluginCallback callback) {
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		return new AndroidLanTcpPlugin(ioExecutor, scheduler, backoff,
+		return new AndroidLanTcpPlugin(ioExecutor, backoff, appContext,
-				appContext, callback, MAX_LATENCY, MAX_IDLE_TIME);
+				callback, MAX_LATENCY, MAX_IDLE_TIME);
 	}
 }

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

@@ -10,12 +10,12 @@ import android.content.pm.PackageManager.NameNotFoundException;
 import android.content.res.Resources;
 import android.net.ConnectivityManager;
 import android.net.NetworkInfo;
+import android.os.FileObserver;
 import android.os.PowerManager;
 
 import net.freehaven.tor.control.EventHandler;
 import net.freehaven.tor.control.TorControlConnection;
 
-import org.briarproject.bramble.PoliteExecutor;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.event.Event;
@@ -31,10 +31,11 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.bramble.api.reporting.DevReporter;
 import org.briarproject.bramble.api.settings.Settings;
 import org.briarproject.bramble.api.settings.event.SettingsUpdatedEvent;
-import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
+import org.briarproject.bramble.util.AndroidUtils;
 import org.briarproject.bramble.util.IoUtils;
 import org.briarproject.bramble.util.StringUtils;
 
@@ -50,16 +51,20 @@ import java.net.InetSocketAddress;
 import java.net.ServerSocket;
 import java.net.Socket;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Scanner;
+import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Executor;
 import java.util.concurrent.Future;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
 import java.util.logging.Logger;
 import java.util.regex.Pattern;
 import java.util.zip.ZipInputStream;
@@ -77,6 +82,7 @@ import static android.net.ConnectivityManager.TYPE_WIFI;
 import static android.os.Build.VERSION.SDK_INT;
 import static android.os.PowerManager.ACTION_DEVICE_IDLE_MODE_CHANGED;
 import static android.os.PowerManager.PARTIAL_WAKE_LOCK;
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.concurrent.TimeUnit.MINUTES;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
@@ -100,18 +106,17 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			"CIRC", "ORCONN", "HS_DESC", "NOTICE", "WARN", "ERR"
 	};
 	private static final String OWNER = "__OwningControllerProcess";
-	private static final int COOKIE_TIMEOUT_MS = 3000;
+	private static final int COOKIE_TIMEOUT = 3000; // Milliseconds
-	private static final int COOKIE_POLLING_INTERVAL_MS = 200;
 	private static final Pattern ONION = Pattern.compile("[a-z2-7]{16}");
 	private static final Logger LOG =
 			Logger.getLogger(TorPlugin.class.getName());
 
-	private final Executor ioExecutor, connectionStatusExecutor;
+	private final Executor ioExecutor;
 	private final ScheduledExecutorService scheduler;
 	private final Context appContext;
 	private final LocationUtils locationUtils;
+	private final DevReporter reporter;
 	private final SocketFactory torSocketFactory;
-	private final Clock clock;
 	private final Backoff backoff;
 	private final DuplexPluginCallback callback;
 	private final String architecture;
@@ -120,6 +125,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private final File torDirectory, torFile, geoIpFile, configFile;
 	private final File doneFile, cookieFile;
 	private final PowerManager.WakeLock wakeLock;
+	private final Lock connectionStatusLock;
 	private final AtomicReference<Future<?>> connectivityCheck =
 			new AtomicReference<>();
 	private final AtomicBoolean used = new AtomicBoolean(false);
@@ -132,15 +138,15 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 	TorPlugin(Executor ioExecutor, ScheduledExecutorService scheduler,
 			Context appContext, LocationUtils locationUtils,
-			SocketFactory torSocketFactory, Clock clock, Backoff backoff,
+			DevReporter reporter, SocketFactory torSocketFactory,
-			DuplexPluginCallback callback, String architecture,
+			Backoff backoff, DuplexPluginCallback callback,
-			int maxLatency, int maxIdleTime) {
+			String architecture, int maxLatency, int maxIdleTime) {
 		this.ioExecutor = ioExecutor;
 		this.scheduler = scheduler;
 		this.appContext = appContext;
 		this.locationUtils = locationUtils;
+		this.reporter = reporter;
 		this.torSocketFactory = torSocketFactory;
-		this.clock = clock;
 		this.backoff = backoff;
 		this.callback = callback;
 		this.architecture = architecture;
@@ -161,9 +167,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		// This tag will prevent Huawei's powermanager from killing us.
 		wakeLock = pm.newWakeLock(PARTIAL_WAKE_LOCK, "LocationManagerService");
 		wakeLock.setReferenceCounted(false);
-		// Don't execute more than one connection status check at a time
+		connectionStatusLock = new ReentrantLock();
-		connectionStatusExecutor = new PoliteExecutor("TorPlugin",
-				ioExecutor, 1);
 	}
 
 	@Override
@@ -186,8 +190,18 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		if (used.getAndSet(true)) throw new IllegalStateException();
 		// Install or update the assets if necessary
 		if (!assetsAreUpToDate()) installAssets();
-		// Start a new Tor process
 		LOG.info("Starting Tor");
+		// Watch for the auth cookie file being updated
+		try {
+			cookieFile.getParentFile().mkdirs();
+			cookieFile.createNewFile();
+		} catch (IOException e) {
+			throw new PluginException(e);
+		}
+		CountDownLatch latch = new CountDownLatch(1);
+		FileObserver obs = new WriteObserver(cookieFile, latch);
+		obs.startWatching();
+		// Start a new Tor process
 		String torPath = torFile.getAbsolutePath();
 		String configPath = configFile.getAbsolutePath();
 		String pid = String.valueOf(android.os.Process.myPid());
@@ -226,16 +240,11 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 				throw new PluginException();
 			}
 			// Wait for the auth cookie file to be created/updated
-			long start = clock.currentTimeMillis();
+			if (!latch.await(COOKIE_TIMEOUT, MILLISECONDS)) {
-			while (cookieFile.length() < 32) {
+				LOG.warning("Auth cookie not created");
-				if (clock.currentTimeMillis() - start > COOKIE_TIMEOUT_MS) {
+				if (LOG.isLoggable(INFO)) listFiles(torDirectory);
-					LOG.warning("Auth cookie not created");
+				throw new PluginException();
-					if (LOG.isLoggable(INFO)) listFiles(torDirectory);
-					throw new PluginException();
-				}
-				Thread.sleep(COOKIE_POLLING_INTERVAL_MS);
 			}
-			LOG.info("Auth cookie created");
 		} catch (InterruptedException e) {
 			LOG.warning("Interrupted while starting Tor");
 			Thread.currentThread().interrupt();
@@ -329,7 +338,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		return zin;
 	}
 
-	private InputStream getConfigInputStream() {
+	private InputStream getConfigInputStream() throws IOException {
 		int resId = getResourceId("torrc");
 		return appContext.getResources().openRawResource(resId);
 	}
@@ -360,7 +369,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			File[] children = f.listFiles();
 			if (children != null) for (File child : children) listFiles(child);
 		} else {
-			LOG.info(f.getAbsolutePath() + " " + f.length());
+			LOG.info(f.getAbsolutePath());
 		}
 	}
 
@@ -380,6 +389,14 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		}
 	}
 
+	private void sendDevReports() {
+		ioExecutor.execute(() -> {
+			// TODO: Trigger this with a TransportEnabledEvent
+			File reportDir = AndroidUtils.getReportDir(appContext);
+			reporter.sendReports(reportDir);
+		});
+	}
+
 	private void bind() {
 		ioExecutor.execute(() -> {
 			// If there's already a port number stored in config, reuse it
@@ -494,7 +511,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	@Override
-	public void stop() {
+	public void stop() throws PluginException {
 		running = false;
 		tryToClose(socket);
 		if (networkStateReceiver != null)
@@ -528,16 +545,20 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	@Override
-	public void poll(Map<ContactId, TransportProperties> contacts) {
+	public void poll(Collection<ContactId> connected) {
 		if (!isRunning()) return;
 		backoff.increment();
-		for (Entry<ContactId, TransportProperties> e : contacts.entrySet()) {
+		Map<ContactId, TransportProperties> remote =
-			connectAndCallBack(e.getKey(), e.getValue());
+				callback.getRemoteProperties();
+		for (Entry<ContactId, TransportProperties> e : remote.entrySet()) {
+			ContactId c = e.getKey();
+			if (!connected.contains(c)) connectAndCallBack(c, e.getValue());
 		}
 	}
 
 	private void connectAndCallBack(ContactId c, TransportProperties p) {
 		ioExecutor.execute(() -> {
+			if (!isRunning()) return;
 			DuplexTransportConnection d = createConnection(p);
 			if (d != null) {
 				backoff.reset();
@@ -547,8 +568,13 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	@Override
-	public DuplexTransportConnection createConnection(TransportProperties p) {
+	public DuplexTransportConnection createConnection(ContactId c) {
 		if (!isRunning()) return null;
+		return createConnection(callback.getRemoteProperties(c));
+	}
+
+	@Nullable
+	private DuplexTransportConnection createConnection(TransportProperties p) {
 		String onion = p.get(PROP_ONION);
 		if (StringUtils.isNullOrEmpty(onion)) return null;
 		if (!ONION.matcher(onion).matches()) {
@@ -598,7 +624,10 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 				connectionStatus.getAndSetCircuitBuilt()) {
 			LOG.info("First circuit built");
 			backoff.reset();
-			if (isRunning()) callback.transportEnabled();
+			if (isRunning()) {
+				sendDevReports();
+				callback.transportEnabled();
+			}
 		}
 	}
 
@@ -627,7 +656,10 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		if (severity.equals("NOTICE") && msg.startsWith("Bootstrapped 100%")) {
 			connectionStatus.setBootstrapped();
 			backoff.reset();
-			if (isRunning()) callback.transportEnabled();
+			if (isRunning()) {
+				sendDevReports();
+				callback.transportEnabled();
+			}
 		}
 	}
 
@@ -637,6 +669,22 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			LOG.info("Descriptor uploaded");
 	}
 
+	private static class WriteObserver extends FileObserver {
+
+		private final CountDownLatch latch;
+
+		private WriteObserver(File file, CountDownLatch latch) {
+			super(file.getAbsolutePath(), CLOSE_WRITE);
+			this.latch = latch;
+		}
+
+		@Override
+		public void onEvent(int event, @Nullable String path) {
+			stopWatching();
+			latch.countDown();
+		}
+	}
+
 	@Override
 	public void eventOccurred(Event e) {
 		if (e instanceof SettingsUpdatedEvent) {
@@ -649,46 +697,55 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void updateConnectionStatus() {
-		connectionStatusExecutor.execute(() -> {
+		ioExecutor.execute(() -> {
 			if (!running) return;
-			Object o = appContext.getSystemService(CONNECTIVITY_SERVICE);
-			ConnectivityManager cm = (ConnectivityManager) o;
-			NetworkInfo net = cm.getActiveNetworkInfo();
-			boolean online = net != null && net.isConnected();
-			boolean wifi = online && net.getType() == TYPE_WIFI;
-			String country = locationUtils.getCurrentCountry();
-			boolean blocked = TorNetworkMetadata.isTorProbablyBlocked(
-					country);
-			Settings s = callback.getSettings();
-			int network = s.getInt(PREF_TOR_NETWORK, PREF_TOR_NETWORK_ALWAYS);
-
-			if (LOG.isLoggable(INFO)) {
-				LOG.info("Online: " + online + ", wifi: " + wifi);
-				if ("".equals(country)) LOG.info("Country code unknown");
-				else LOG.info("Country code: " + country);
-			}
-
 			try {
-				if (!online) {
+				connectionStatusLock.lock();
-					LOG.info("Disabling network, device is offline");
+				updateConnectionStatusLocked();
-					enableNetwork(false);
+			} finally {
-				} else if (blocked) {
+				connectionStatusLock.unlock();
-					LOG.info("Disabling network, country is blocked");
-					enableNetwork(false);
-				} else if (network == PREF_TOR_NETWORK_NEVER
-						|| (network == PREF_TOR_NETWORK_WIFI && !wifi)) {
-					LOG.info("Disabling network due to data setting");
-					enableNetwork(false);
-				} else {
-					LOG.info("Enabling network");
-					enableNetwork(true);
-				}
-			} catch (IOException e) {
-				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			}
 		});
 	}
 
+	// Locking: connectionStatusLock
+	private void updateConnectionStatusLocked() {
+		Object o = appContext.getSystemService(CONNECTIVITY_SERVICE);
+		ConnectivityManager cm = (ConnectivityManager) o;
+		NetworkInfo net = cm.getActiveNetworkInfo();
+		boolean online = net != null && net.isConnected();
+		boolean wifi = online && net.getType() == TYPE_WIFI;
+		String country = locationUtils.getCurrentCountry();
+		boolean blocked = TorNetworkMetadata.isTorProbablyBlocked(country);
+		Settings s = callback.getSettings();
+		int network = s.getInt(PREF_TOR_NETWORK, PREF_TOR_NETWORK_ALWAYS);
+
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Online: " + online + ", wifi: " + wifi);
+			if ("".equals(country)) LOG.info("Country code unknown");
+			else LOG.info("Country code: " + country);
+		}
+
+		try {
+			if (!online) {
+				LOG.info("Disabling network, device is offline");
+				enableNetwork(false);
+			} else if (blocked) {
+				LOG.info("Disabling network, country is blocked");
+				enableNetwork(false);
+			} else if (network == PREF_TOR_NETWORK_NEVER
+					|| (network == PREF_TOR_NETWORK_WIFI && !wifi)) {
+				LOG.info("Disabling network due to data setting");
+				enableNetwork(false);
+			} else {
+				LOG.info("Enabling network");
+				enableNetwork(true);
+			}
+		} catch (IOException e) {
+			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+		}
+	}
+
 	private void scheduleConnectionStatusUpdate() {
 		Future<?> newConnectivityCheck =
 				scheduler.schedule(this::updateConnectionStatus, 1, MINUTES);
@@ -730,7 +787,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 		private synchronized void enableNetwork(boolean enable) {
 			networkEnabled = enable;
-			if (!enable) circuitBuilt = false;
+			circuitBuilt = false;
 		}
 
 		private synchronized boolean isConnected() {

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

@@ -12,7 +12,7 @@ import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
-import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.reporting.DevReporter;
 import org.briarproject.bramble.api.system.LocationUtils;
 import org.briarproject.bramble.util.AndroidUtils;
 
@@ -40,24 +40,24 @@ public class TorPluginFactory implements DuplexPluginFactory {
 	private final ScheduledExecutorService scheduler;
 	private final Context appContext;
 	private final LocationUtils locationUtils;
+	private final DevReporter reporter;
 	private final EventBus eventBus;
 	private final SocketFactory torSocketFactory;
 	private final BackoffFactory backoffFactory;
-	private final Clock clock;
 
 	public TorPluginFactory(Executor ioExecutor,
 			ScheduledExecutorService scheduler, Context appContext,
-			LocationUtils locationUtils, EventBus eventBus,
+			LocationUtils locationUtils, DevReporter reporter,
-			SocketFactory torSocketFactory, BackoffFactory backoffFactory,
+			EventBus eventBus, SocketFactory torSocketFactory,
-			Clock clock) {
+			BackoffFactory backoffFactory) {
 		this.ioExecutor = ioExecutor;
 		this.scheduler = scheduler;
 		this.appContext = appContext;
 		this.locationUtils = locationUtils;
+		this.reporter = reporter;
 		this.eventBus = eventBus;
 		this.torSocketFactory = torSocketFactory;
 		this.backoffFactory = backoffFactory;
-		this.clock = clock;
 	}
 
 	@Override
@@ -94,7 +94,7 @@ public class TorPluginFactory implements DuplexPluginFactory {
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		TorPlugin plugin = new TorPlugin(ioExecutor, scheduler, appContext,
-				locationUtils, torSocketFactory, clock, backoff, callback,
+				locationUtils, reporter, torSocketFactory, backoff, callback,
 				architecture, MAX_LATENCY, MAX_IDLE_TIME);
 		eventBus.addListener(plugin);
 		return plugin;

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

@@ -9,7 +9,6 @@ import android.net.wifi.WifiConfiguration;
 import android.net.wifi.WifiManager;
 import android.os.Build;
 import android.os.Parcel;
-import android.os.StrictMode;
 import android.provider.Settings;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
@@ -67,12 +66,9 @@ class AndroidSecureRandomProvider extends LinuxSecureRandomProvider {
 
 	@Override
 	protected void writeSeed() {
-		// Silence strict mode
-		StrictMode.ThreadPolicy tp = StrictMode.allowThreadDiskWrites();
 		super.writeSeed();
 		if (Build.VERSION.SDK_INT >= 16 && Build.VERSION.SDK_INT <= 18)
 			applyOpenSslFix();
-		StrictMode.setThreadPolicy(tp);
 	}
 
 	// Based on https://android-developers.googleblog.com/2013/08/some-securerandom-thoughts.html

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

@@ -3,24 +3,41 @@ package org.briarproject.bramble.util;
 import android.annotation.SuppressLint;
 import android.bluetooth.BluetoothAdapter;
 import android.content.Context;
-import android.content.SharedPreferences;
+import android.net.ConnectivityManager;
+import android.net.Network;
+import android.net.NetworkInfo;
+import android.net.wifi.WifiInfo;
+import android.net.wifi.WifiManager;
 import android.os.Build;
 import android.provider.Settings;
 
 import java.io.File;
+import java.net.InetAddress;
+import java.net.InterfaceAddress;
+import java.net.NetworkInterface;
+import java.net.SocketException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 import java.util.logging.Logger;
 
+import javax.annotation.Nullable;
+
+import static android.content.Context.CONNECTIVITY_SERVICE;
 import static android.content.Context.MODE_PRIVATE;
+import static android.content.Context.WIFI_SERVICE;
+import static android.os.Build.VERSION.SDK_INT;
+import static java.net.NetworkInterface.getNetworkInterfaces;
+import static java.util.Collections.list;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
+import static org.briarproject.bramble.util.StringUtils.ipToString;
+import static org.briarproject.bramble.util.StringUtils.toHexString;
 
+@SuppressLint("HardwareIds")
 public class AndroidUtils {
 
-	private static final Logger LOG =
-			Logger.getLogger(AndroidUtils.class.getName());
-
 	// Fake Bluetooth address returned by BluetoothAdapter on API 23 and later
 	private static final String FAKE_BLUETOOTH_ADDRESS = "02:00:00:00:00:00";
 
@@ -29,7 +46,7 @@ public class AndroidUtils {
 	@SuppressWarnings("deprecation")
 	public static Collection<String> getSupportedArchitectures() {
 		List<String> abis = new ArrayList<>();
-		if (Build.VERSION.SDK_INT >= 21) {
+		if (SDK_INT >= 21) {
 			abis.addAll(Arrays.asList(Build.SUPPORTED_ABIS));
 		} else {
 			abis.add(Build.CPU_ABI);
@@ -41,7 +58,6 @@ public class AndroidUtils {
 	public static String getBluetoothAddress(Context ctx,
 			BluetoothAdapter adapter) {
 		// Return the adapter's address if it's valid and not fake
-		@SuppressLint("HardwareIds")
 		String address = adapter.getAddress();
 		if (isValidBluetoothAddress(address)) return address;
 		// Return the address from settings if it's valid and not fake
@@ -58,31 +74,139 @@ public class AndroidUtils {
 				&& !address.equals(FAKE_BLUETOOTH_ADDRESS);
 	}
 
-	public static void deleteAppData(Context ctx, SharedPreferences... clear) {
+	public static void deleteAppData(Context ctx) {
-		// Clear and commit shared preferences
-		for (SharedPreferences prefs : clear) {
-			if (!prefs.edit().clear().commit())
-				LOG.warning("Could not clear shared preferences");
-		}
-		// Delete files, except lib and shared_prefs directories
 		File dataDir = new File(ctx.getApplicationInfo().dataDir);
 		File[] children = dataDir.listFiles();
-		if (children == null) {
+		if (children != null) {
-			LOG.warning("Could not list files in app data dir");
-		} else {
 			for (File child : children) {
-				String name = child.getName();
+				if (!child.getName().equals("lib"))
-				if (!name.equals("lib") && !name.equals("shared_prefs")) {
 					IoUtils.deleteFileOrDir(child);
-				}
 			}
 		}
 		// Recreate the cache dir as some OpenGL drivers expect it to exist
-		if (!new File(dataDir, "cache").mkdir())
+		new File(dataDir, "cache").mkdir();
-			LOG.warning("Could not recreate cache dir");
 	}
 
 	public static File getReportDir(Context ctx) {
 		return ctx.getDir(STORED_REPORTS, MODE_PRIVATE);
 	}
+
+	public static void logNetworkState(Context ctx, Logger logger) {
+		if (!logger.isLoggable(INFO)) return;
+
+		Object o = ctx.getSystemService(CONNECTIVITY_SERVICE);
+		if (o == null) throw new AssertionError();
+		ConnectivityManager cm = (ConnectivityManager) o;
+		o = ctx.getApplicationContext().getSystemService(WIFI_SERVICE);
+		if (o == null) throw new AssertionError();
+		WifiManager wm = (WifiManager) o;
+
+		StringBuilder s = new StringBuilder();
+		logWifiInfo(s, wm.getConnectionInfo());
+		logNetworkInfo(s, cm.getActiveNetworkInfo(), true);
+		if (SDK_INT >= 21) {
+			for (Network network : cm.getAllNetworks())
+				logNetworkInfo(s, cm.getNetworkInfo(network), false);
+		} else {
+			for (NetworkInfo info : cm.getAllNetworkInfo())
+				logNetworkInfo(s, info, false);
+		}
+		try {
+			for (NetworkInterface iface : list(getNetworkInterfaces()))
+				logNetworkInterface(s, iface);
+		} catch (SocketException e) {
+			logger.log(WARNING, e.toString(), e);
+		}
+		logger.log(INFO, s.toString());
+	}
+
+	private static void logWifiInfo(StringBuilder s, @Nullable WifiInfo info) {
+		if (info == null) {
+			s.append("Wifi info: null\n");
+			return;
+		}
+		s.append("Wifi info:\n");
+		s.append("\tSSID: ").append(info.getSSID()).append("\n");
+		s.append("\tBSSID: ").append(info.getBSSID()).append("\n");
+		s.append("\tMAC address: ").append(info.getMacAddress()).append("\n");
+		s.append("\tIP address: ")
+				.append(ipToString(info.getIpAddress())).append("\n");
+		s.append("\tSupplicant state: ")
+				.append(info.getSupplicantState()).append("\n");
+		s.append("\tNetwork ID: ").append(info.getNetworkId()).append("\n");
+		s.append("\tLink speed: ").append(info.getLinkSpeed()).append("\n");
+		s.append("\tRSSI: ").append(info.getRssi()).append("\n");
+		if (info.getHiddenSSID()) s.append("\tHidden SSID\n");
+		if (SDK_INT >= 21)
+			s.append("\tFrequency: ").append(info.getFrequency()).append("\n");
+	}
+
+	private static void logNetworkInfo(StringBuilder s,
+			@Nullable NetworkInfo info, boolean active) {
+		if (info == null) {
+			if (active) s.append("Active network info: null\n");
+			else s.append("Network info: null\n");
+			return;
+		}
+		if (active) s.append("Active network info:\n");
+		else s.append("Network info:\n");
+		s.append("\tType: ").append(info.getTypeName())
+				.append(" (").append(info.getType()).append(")\n");
+		s.append("\tSubtype: ").append(info.getSubtypeName())
+				.append(" (").append(info.getSubtype()).append(")\n");
+		s.append("\tState: ").append(info.getState()).append("\n");
+		s.append("\tDetailed state: ")
+				.append(info.getDetailedState()).append("\n");
+		s.append("\tReason: ").append(info.getReason()).append("\n");
+		s.append("\tExtra info: ").append(info.getExtraInfo()).append("\n");
+		if (info.isAvailable()) s.append("\tAvailable\n");
+		if (info.isConnected()) s.append("\tConnected\n");
+		if (info.isConnectedOrConnecting())
+			s.append("\tConnected or connecting\n");
+		if (info.isFailover()) s.append("\tFailover\n");
+		if (info.isRoaming()) s.append("\tRoaming\n");
+	}
+
+	private static void logNetworkInterface(StringBuilder s,
+			NetworkInterface iface) throws SocketException {
+		s.append("Network interface:\n");
+		s.append("\tName: ").append(iface.getName()).append("\n");
+		s.append("\tDisplay name: ")
+				.append(iface.getDisplayName()).append("\n");
+		s.append("\tHardware address: ")
+				.append(hexOrNull(iface.getHardwareAddress())).append("\n");
+		if (iface.isLoopback()) s.append("\tLoopback\n");
+		if (iface.isPointToPoint()) s.append("\tPoint-to-point\n");
+		if (iface.isVirtual()) s.append("\tVirtual\n");
+		if (iface.isUp()) s.append("\tUp\n");
+		if (SDK_INT >= 19)
+			s.append("\tIndex: ").append(iface.getIndex()).append("\n");
+		for (InterfaceAddress addr : iface.getInterfaceAddresses()) {
+			s.append("\tInterface address:\n");
+			logInetAddress(s, addr.getAddress());
+			s.append("\t\tPrefix length: ")
+					.append(addr.getNetworkPrefixLength()).append("\n");
+		}
+	}
+
+	private static void logInetAddress(StringBuilder s, InetAddress addr) {
+		s.append("\t\tAddress: ")
+				.append(hexOrNull(addr.getAddress())).append("\n");
+		s.append("\t\tHost address: ")
+				.append(addr.getHostAddress()).append("\n");
+		if (addr.isLoopbackAddress()) s.append("\t\tLoopback\n");
+		if (addr.isLinkLocalAddress()) s.append("\t\tLink-local\n");
+		if (addr.isSiteLocalAddress()) s.append("\t\tSite-local\n");
+		if (addr.isAnyLocalAddress()) s.append("\t\tAny local (wildcard)\n");
+		if (addr.isMCNodeLocal()) s.append("\t\tMulticast node-local\n");
+		if (addr.isMCLinkLocal()) s.append("\t\tMulticast link-local\n");
+		if (addr.isMCSiteLocal()) s.append("\t\tMulticast site-local\n");
+		if (addr.isMCOrgLocal()) s.append("\t\tMulticast org-local\n");
+		if (addr.isMCGlobal()) s.append("\t\tMulticast global\n");
+	}
+
+	@Nullable
+	private static String hexOrNull(@Nullable byte[] b) {
+		return b == null ? null : toHexString(b);
+	}
 }

bramble-api/build.gradle

@@ -2,7 +2,6 @@ apply plugin: 'java-library'
 sourceCompatibility = 1.8
 targetCompatibility = 1.8
 
-apply plugin: 'ru.vyarus.animalsniffer'
 apply plugin: 'witness'
 
 dependencies {
@@ -15,8 +14,6 @@ dependencies {
 	testImplementation "org.jmock:jmock-legacy:2.8.2"
 	testImplementation "org.hamcrest:hamcrest-library:1.3"
 	testImplementation "org.hamcrest:hamcrest-core:1.3"
-
-	signature 'org.codehaus.mojo.signature:java16:1.1@signature'
 }
 
 dependencyVerification {
@@ -29,9 +26,6 @@ dependencyVerification {
 			'org.apache.ant:ant-launcher:1.9.4:ant-launcher-1.9.4.jar:7bccea20b41801ca17bcbc909a78c835d0f443f12d639c77bd6ae3d05861608d',
 			'org.apache.ant:ant:1.9.4:ant-1.9.4.jar:649ae0730251de07b8913f49286d46bba7b92d47c5f332610aa426c4f02161d8',
 			'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
-			'org.codehaus.mojo.signature:java16:1.1:java16-1.1.signature:53799223a2c98dba2d0add810bed76315460df285c69e4f397ae6098f87dd619',
-			'org.codehaus.mojo:animal-sniffer-ant-tasks:1.16:animal-sniffer-ant-tasks-1.16.jar:890040976fbe2d584619a6a61b1fd2e925b3b5eb342a85eb2762c467c0d64e90',
-			'org.codehaus.mojo:animal-sniffer:1.16:animal-sniffer-1.16.jar:72be8bcc226ba43b937c722a08a07852bfa1b11400089265d5df0ee7b38b1d52',
 			'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
 			'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
 			'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',
@@ -39,7 +33,6 @@ dependencyVerification {
 			'org.jmock:jmock-testjar:2.8.2:jmock-testjar-2.8.2.jar:8900860f72c474e027cf97fe78dcbf154a1aa7fc62b6845c5fb4e4f3c7bc8760',
 			'org.jmock:jmock:2.8.2:jmock-2.8.2.jar:6c73cb4a2e6dbfb61fd99c9a768539c170ab6568e57846bd60dbf19596b65b16',
 			'org.objenesis:objenesis:2.1:objenesis-2.1.jar:c74330cc6b806c804fd37e74487b4fe5d7c2750c5e15fbc6efa13bdee1bdef80',
-			'org.ow2.asm:asm-all:5.2:asm-all-5.2.jar:7fbffbc1db3422e2101689fd88df8384b15817b52b9b2b267b9f6d2511dc198d',
 			'org.ow2.asm:asm:5.0.4:asm-5.0.4.jar:896618ed8ae62702521a78bc7be42b7c491a08e6920a15f89a3ecdec31e9a220',
 	]
 }
@@ -55,3 +48,8 @@ task jarTest(type: Jar, dependsOn: testClasses) {
 artifacts {
 	testOutput jarTest
 }
+
+// If a Java 6 JRE is available, check we're not using any Java 7 or 8 APIs
+tasks.withType(JavaCompile) {
+	useJava6StandardLibrary(it)
+}

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

@@ -7,8 +7,6 @@ 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.nullsafety.NotNullByDefault;
-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;
@@ -90,10 +88,6 @@ public interface ClientHelper {
 	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;
@@ -105,15 +99,8 @@ public interface ClientHelper {
 	byte[] sign(String label, BdfList toSign, byte[] privateKey)
 			throws FormatException, GeneralSecurityException;
 
-	void verifySignature(byte[] signature, String label, BdfList signed,
+	void verifySignature(String label, byte[] sig, byte[] publicKey,
-			byte[] publicKey) throws FormatException, GeneralSecurityException;
+			BdfList signed) throws FormatException, GeneralSecurityException;
 
 	Author parseAndValidateAuthor(BdfList author) throws FormatException;
-
-	TransportProperties parseAndValidateTransportProperties(
-			BdfDictionary properties) throws FormatException;
-
-	Map<TransportId, TransportProperties> parseAndValidateTransportPropertiesMap(
-			BdfDictionary properties) throws FormatException;
-
 }

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

@@ -12,19 +12,19 @@ public interface ContactGroupFactory {
 	/**
 	 * Creates a group that is not shared with any contacts.
 	 */
-	Group createLocalGroup(ClientId clientId, int majorVersion);
+	Group createLocalGroup(ClientId clientId, int clientVersion);
 
 	/**
 	 * Creates a group for the given client to share with the given contact.
 	 */
-	Group createContactGroup(ClientId clientId, int majorVersion,
+	Group createContactGroup(ClientId clientId, int clientVersion,
 			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,
+	Group createContactGroup(ClientId clientId, int clientVersion,
 			AuthorId authorId1, AuthorId authorId2);
 
 }

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

@@ -13,9 +13,9 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 public interface ContactExchangeTask {
 
 	/**
-	 * The current version of the contact exchange protocol.
+	 * The current version of the contact exchange protocol
 	 */
-	byte PROTOCOL_VERSION = 1;
+	int PROTOCOL_VERSION = 0;
 
 	/**
 	 * Label for deriving Alice's header key from the master secret.

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

@@ -6,7 +6,7 @@ import javax.annotation.concurrent.Immutable;
 
 /**
  * Type-safe wrapper for an integer that uniquely identifies a contact within
- * the scope of the local device.
+ * the scope of a single node.
  */
 @Immutable
 @NotNullByDefault

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

@@ -5,7 +5,6 @@ import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
-import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.util.Collection;
@@ -14,40 +13,30 @@ import java.util.Collection;
 public interface ContactManager {
 
 	/**
-	 * Registers a hook to be called whenever a contact is added or removed.
+	 * Registers a hook to be called whenever a contact is added.
-	 * This method should be called before
-	 * {@link LifecycleManager#startServices(String)}.
 	 */
-	void registerContactHook(ContactHook hook);
+	void registerAddContactHook(AddContactHook hook);
 
 	/**
-	 * Stores a contact associated with the given local and remote pseudonyms,
+	 * Registers a hook to be called whenever a contact is removed.
-	 * derives and stores transport keys for each transport, and returns an ID
+	 */
-	 * for the contact.
+	void registerRemoveContactHook(RemoveContactHook hook);
-	 *
+
-	 * @param alice true if the local party is Alice
+	/**
+	 * Stores a contact within the given transaction associated with the given
+	 * local and remote pseudonyms, and returns an ID for the contact.
 	 */
 	ContactId addContact(Transaction txn, Author remote, AuthorId local,
 			SecretKey master, long timestamp, boolean alice, boolean verified,
 			boolean active) throws DbException;
 
 	/**
-	 * Stores a contact associated with the given local and remote pseudonyms
+	 * Stores a contact associated with the given local and remote pseudonyms,
 	 * and returns an ID for the contact.
 	 */
-	ContactId addContact(Transaction txn, Author remote, AuthorId local,
+	ContactId addContact(Author remote, AuthorId local,
-			boolean verified, boolean active) throws DbException;
+			SecretKey master, long timestamp, boolean alice, boolean verified,
-
+			boolean active) throws DbException;
-	/**
-	 * Stores a contact associated with the given local and remote pseudonyms,
-	 * derives and stores transport keys for each transport, and returns an ID
-	 * for the contact.
-	 *
-	 * @param alice true if the local party is Alice
-	 */
-	ContactId addContact(Author remote, AuthorId local, SecretKey master,
-			long timestamp, boolean alice, boolean verified, boolean active)
-			throws DbException;
 
 	/**
 	 * Returns the contact with the given ID.
@@ -105,10 +94,11 @@ public interface ContactManager {
 	boolean contactExists(AuthorId remoteAuthorId, AuthorId localAuthorId)
 			throws DbException;
 
-	interface ContactHook {
+	interface AddContactHook {
-
 		void addingContact(Transaction txn, Contact c) throws DbException;
+	}
 
+	interface RemoveContactHook {
 		void removingContact(Transaction txn, Contact c) throws DbException;
 	}
 }

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

@@ -1,9 +0,0 @@
-package org.briarproject.bramble.api.contact;
-
-/**
- * Record types for the contact exchange protocol.
- */
-public interface RecordTypes {
-
-	byte CONTACT_INFO = 0;
-}

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

@@ -67,8 +67,8 @@ public interface CryptoComponent {
 	 * signature created for another purpose
 	 * @return true if the signature was valid, false otherwise.
 	 */
-	boolean verifySignature(byte[] signature, String label, byte[] signed,
+	boolean verify(String label, byte[] signedData, byte[] publicKey,
-			byte[] publicKey) throws GeneralSecurityException;
+			byte[] signature) throws GeneralSecurityException;
 
 	/**
 	 * Returns the hash of the given inputs. The inputs are unambiguously
@@ -91,18 +91,6 @@ public interface CryptoComponent {
 	 */
 	byte[] mac(String label, SecretKey macKey, byte[]... inputs);
 
-	/**
-	 * Verifies that the given message authentication code is valid for the
-	 * given secret key and inputs.
-	 *
-	 * @param label a namespaced label indicating the purpose of this MAC, to
-	 * prevent it from being repurposed or colliding with a MAC created for
-	 * another purpose
-	 * @return true if the MAC was valid, false otherwise.
-	 */
-	boolean verifyMac(byte[] mac, String label, SecretKey macKey,
-			byte[]... inputs);
-
 	/**
 	 * Encrypts and authenticates the given plaintext so it can be written to
 	 * storage. The encryption and authentication keys are derived from the

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

@@ -16,10 +16,4 @@ public interface CryptoConstants {
 	 * The maximum length of a signature in bytes.
 	 */
 	int MAX_SIGNATURE_BYTES = 64;
-
-	/**
-	 * The length of a MAC in bytes.
-	 */
-	int MAC_BYTES = SecretKey.LENGTH;
-
 }

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

@@ -5,7 +5,7 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import javax.annotation.concurrent.Immutable;
 
 /**
- * A key pair consisting of a {@link PublicKey} and a {@link PrivateKey}.
+ * A key pair consisting of a {@link PublicKey} and a {@link PrivateKey).
  */
 @Immutable
 @NotNullByDefault

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

@@ -14,10 +14,9 @@ public interface TransportCrypto {
 	 * rotation period from the given master secret.
 	 *
 	 * @param alice whether the keys are for use by Alice or Bob.
-	 * @param active whether the keys are usable for outgoing streams.
 	 */
 	TransportKeys deriveTransportKeys(TransportId t, SecretKey master,
-			long rotationPeriod, boolean alice, boolean active);
+			long rotationPeriod, boolean alice);
 
 	/**
 	 * Rotates the given transport keys to the given rotation period. If the

bramble-api/src/main/java/org/briarproject/bramble/api/data/BdfDictionary.java

@@ -24,9 +24,9 @@ public class BdfDictionary extends TreeMap<String, Object> {
 	 * );
 	 * </pre>
 	 */
-	public static BdfDictionary of(Entry<String, ?>... entries) {
+	public static BdfDictionary of(Entry<String, Object>... entries) {
 		BdfDictionary d = new BdfDictionary();
-		for (Entry<String, ?> e : entries) d.put(e.getKey(), e.getValue());
+		for (Entry<String, Object> e : entries) d.put(e.getKey(), e.getValue());
 		return d;
 	}
 
@@ -34,7 +34,7 @@ public class BdfDictionary extends TreeMap<String, Object> {
 		super();
 	}
 
-	public BdfDictionary(Map<String, ?> m) {
+	public BdfDictionary(Map<String, Object> m) {
 		super(m);
 	}
 

bramble-api/src/main/java/org/briarproject/bramble/api/data/BdfReader.java

@@ -8,7 +8,6 @@ import java.io.IOException;
 public interface BdfReader {
 
 	int DEFAULT_NESTED_LIMIT = 5;
-	int DEFAULT_MAX_BUFFER_SIZE = 64 * 1024;
 
 	boolean eof() throws IOException;
 
@@ -40,13 +39,13 @@ public interface BdfReader {
 
 	boolean hasString() throws IOException;
 
-	String readString() throws IOException;
+	String readString(int maxLength) throws IOException;
 
 	void skipString() throws IOException;
 
 	boolean hasRaw() throws IOException;
 
-	byte[] readRaw() throws IOException;
+	byte[] readRaw(int maxLength) throws IOException;
 
 	void skipRaw() throws IOException;
 

bramble-api/src/main/java/org/briarproject/bramble/api/data/BdfReaderFactory.java

@@ -9,6 +9,5 @@ public interface BdfReaderFactory {
 
 	BdfReader createReader(InputStream in);
 
-	BdfReader createReader(InputStream in, int nestedLimit,
+	BdfReader createReader(InputStream in, int nestedLimit);
-			int maxBufferSize);
 }

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

@@ -18,8 +18,7 @@ import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.MessageStatus;
 import org.briarproject.bramble.api.sync.Offer;
 import org.briarproject.bramble.api.sync.Request;
-import org.briarproject.bramble.api.transport.KeySet;
+import org.briarproject.bramble.api.sync.ValidationManager;
-import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.util.Collection;
@@ -104,11 +103,10 @@ public interface DatabaseComponent {
 			throws DbException;
 
 	/**
-	 * Stores the given transport keys for the given contact and returns a
+	 * Stores transport keys for a newly added contact.
-	 * key set ID.
 	 */
-	KeySetId addTransportKeys(Transaction txn, ContactId c,
+	void addTransportKeys(Transaction txn, ContactId c, TransportKeys k)
-			TransportKeys k) throws DbException;
+			throws DbException;
 
 	/**
 	 * Returns true if the database contains the given contact for the given
@@ -130,8 +128,8 @@ public interface DatabaseComponent {
 
 	/**
 	 * Deletes the message with the given ID. Unlike
-	 * {@link #removeMessage(Transaction, MessageId)}, the message ID,
+	 * {@link #removeMessage(Transaction, MessageId)}, the message ID and any
-	 * dependencies, metadata, and any other associated state are not deleted.
+	 * other associated data are not deleted.
 	 */
 	void deleteMessage(Transaction txn, MessageId m) throws DbException;
 
@@ -235,8 +233,7 @@ public interface DatabaseComponent {
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<Group> getGroups(Transaction txn, ClientId c, int majorVersion)
+	Collection<Group> getGroups(Transaction txn, ClientId c) throws DbException;
-			throws DbException;
 
 	/**
 	 * Returns the given group's visibility to the given contact, or
@@ -261,14 +258,6 @@ public interface DatabaseComponent {
 	 */
 	Collection<LocalAuthor> getLocalAuthors(Transaction txn) throws DbException;
 
-	/**
-	 * Returns the IDs of all delivered messages in the given group.
-	 * <p/>
-	 * Read-only.
-	 */
-	Collection<MessageId> getMessageIds(Transaction txn, GroupId g)
-		throws DbException;
-
 	/**
 	 * Returns the IDs of any messages that need to be validated.
 	 * <p/>
@@ -313,9 +302,9 @@ public interface DatabaseComponent {
 			throws DbException;
 
 	/**
-	 * Returns the metadata for any delivered messages in the given group with
+	 * Returns the metadata for any messages in the given group with metadata
-	 * metadata that matches all entries in the given query. If the query is
+	 * that matches all entries in the given query. If the query is empty, the
-	 * empty, the metadata for all delivered messages is returned.
+	 * metadata for all messages is returned.
 	 * <p/>
 	 * Read-only.
 	 */
@@ -331,8 +320,8 @@ public interface DatabaseComponent {
 			throws DbException;
 
 	/**
-	 * Returns the metadata for the given delivered or pending message.
+	 * Returns the metadata for the given delivered and pending message.
-	 * This is only meant to be used by the ValidationManager.
+	 * This is meant to be only used by the ValidationManager
 	 * <p/>
 	 * Read-only.
 	 */
@@ -340,8 +329,8 @@ public interface DatabaseComponent {
 			throws DbException;
 
 	/**
-	 * Returns the status of all delivered messages in the given group with
+	 * Returns the status of all messages in the given group with respect to
-	 * respect to the given contact.
+	 * the given contact.
 	 * <p/>
 	 * Read-only.
 	 */
@@ -350,8 +339,12 @@ public interface DatabaseComponent {
 
 	/**
 	 * Returns the IDs and states of all dependencies of the given message.
-	 * For missing dependencies and dependencies in other groups, the state
+	 * Missing dependencies have the state
-	 * {@link State UNKNOWN} is returned.
+	 * {@link ValidationManager.State UNKNOWN}.
+	 * Dependencies in other groups have the state
+	 * {@link ValidationManager.State INVALID}.
+	 * Note that these states are not set on the dependencies themselves; the
+	 * returned states should only be taken in the context of the given message.
 	 * <p/>
 	 * Read-only.
 	 */
@@ -359,9 +352,9 @@ public interface DatabaseComponent {
 			throws DbException;
 
 	/**
-	 * Returns the IDs and states of all dependents of the given message.
+	 * Returns all IDs of messages that depend on the given message.
-	 * Dependents in other groups are not returned. If the given message is
+	 * Messages in other groups that declare a dependency on the given message
-	 * missing, no dependents are returned.
+	 * will be returned even though such dependencies are invalid.
 	 * <p/>
 	 * Read-only.
 	 */
@@ -376,8 +369,8 @@ public interface DatabaseComponent {
 	State getMessageState(Transaction txn, MessageId m) throws DbException;
 
 	/**
-	 * Returns the status of the given delivered message with respect to the
+	 * Returns the status of the given message with respect to the given
-	 * given contact.
+	 * contact.
 	 * <p/>
 	 * Read-only.
 	 */
@@ -406,14 +399,15 @@ public interface DatabaseComponent {
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<KeySet> getTransportKeys(Transaction txn, TransportId t)
+	Map<ContactId, TransportKeys> getTransportKeys(Transaction txn,
-			throws DbException;
+			TransportId t) throws DbException;
 
 	/**
-	 * Increments the outgoing stream counter for the given transport keys.
+	 * Increments the outgoing stream counter for the given contact and
+	 * transport in the given rotation period .
 	 */
-	void incrementStreamCounter(Transaction txn, TransportId t, KeySetId k)
+	void incrementStreamCounter(Transaction txn, ContactId c, TransportId t,
-			throws DbException;
+			long rotationPeriod) throws DbException;
 
 	/**
 	 * Merges the given metadata with the existing metadata for the given
@@ -483,12 +477,6 @@ public interface DatabaseComponent {
 	 */
 	void removeTransport(Transaction txn, TransportId t) throws DbException;
 
-	/**
-	 * Removes the given transport keys from the database.
-	 */
-	void removeTransportKeys(Transaction txn, TransportId t, KeySetId k)
-		throws DbException;
-
 	/**
 	 * Marks the given contact as verified.
 	 */
@@ -524,21 +512,15 @@ public interface DatabaseComponent {
 			Collection<MessageId> dependencies) throws DbException;
 
 	/**
-	 * Sets the reordering window for the given key set and transport in the
+	 * Sets the reordering window for the given contact and transport in the
 	 * given rotation period.
 	 */
-	void setReorderingWindow(Transaction txn, KeySetId k, TransportId t,
+	void setReorderingWindow(Transaction txn, ContactId c, TransportId t,
 			long rotationPeriod, long base, byte[] bitmap) throws DbException;
 
-	/**
-	 * Marks the given transport keys as usable for outgoing streams.
-	 */
-	void setTransportKeysActive(Transaction txn, TransportId t, KeySetId k)
-		throws DbException;
-
 	/**
 	 * Stores the given transport keys, deleting any keys they have replaced.
 	 */
-	void updateTransportKeys(Transaction txn, Collection<KeySet> keys)
+	void updateTransportKeys(Transaction txn,
-			throws DbException;
+			Map<ContactId, TransportKeys> keys) throws DbException;
 }

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

@@ -14,8 +14,6 @@ public interface DatabaseConfig {
 
 	File getDatabaseDirectory();
 
-	File getDatabaseKeyDirectory();
-
 	void setEncryptionKey(SecretKey key);
 
 	@Nullable

bramble-api/src/main/java/org/briarproject/bramble/api/keyagreement/event/KeyAgreementStoppedListeningEvent.java

@@ -1,9 +0,0 @@
-package org.briarproject.bramble.api.keyagreement.event;
-
-import org.briarproject.bramble.api.event.Event;
-
-/**
- * An event that is broadcast when a BQP task stops listening.
- */
-public class KeyAgreementStoppedListeningEvent extends Event {
-}

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

@@ -43,20 +43,17 @@ public interface LifecycleManager {
 	}
 
 	/**
-	 * Registers a {@link Service} to be started and stopped. This method
+	 * Registers a {@link Service} to be started and stopped.
-	 * should be called before {@link #startServices(String)}.
 	 */
 	void registerService(Service s);
 
 	/**
-	 * Registers a {@link Client} to be started. This method should be called
+	 * Registers a {@link Client} to be started.
-	 * before {@link #startServices(String)}.
 	 */
 	void registerClient(Client c);
 
 	/**
-	 * Registers an {@link ExecutorService} to be shut down. This method
+	 * Registers an {@link ExecutorService} to be shut down.
-	 * should be called before {@link #startServices(String)}.
 	 */
 	void registerForShutdown(ExecutorService e);
 

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/FileConstants.java

@@ -1,6 +0,0 @@
-package org.briarproject.bramble.api.plugin;
-
-public interface FileConstants {
-
-	String PROP_PATH = "path";
-}

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/Plugin.java

@@ -2,9 +2,8 @@ package org.briarproject.bramble.api.plugin;
 
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.properties.TransportProperties;
 
-import java.util.Map;
+import java.util.Collection;
 
 @NotNullByDefault
 public interface Plugin {
@@ -40,19 +39,21 @@ public interface Plugin {
 	boolean isRunning();
 
 	/**
-	 * Returns true if the plugin should be polled periodically to attempt to
+	 * Returns true if the plugin's {@link #poll(Collection)} method should be
-	 * establish connections.
+	 * called periodically to attempt to establish connections.
 	 */
 	boolean shouldPoll();
 
 	/**
-	 * Returns the desired interval in milliseconds between polling attempts.
+	 * Returns the desired interval in milliseconds between calls to the
+	 * plugin's {@link #poll(Collection)} method.
 	 */
 	int getPollingInterval();
 
 	/**
-	 * Attempts to establish connections to the given contacts, passing any
+	 * Attempts to establish connections to contacts, passing any created
-	 * created connections to the callback.
+	 * connections to the callback. To avoid creating redundant connections,
+	 * the plugin may exclude the given contacts from polling.
 	 */
-	void poll(Map<ContactId, TransportProperties> contacts);
+	void poll(Collection<ContactId> connected);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/PluginCallback.java

@@ -1,9 +1,12 @@
 package org.briarproject.bramble.api.plugin;
 
+import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.settings.Settings;
 
+import java.util.Map;
+
 /**
  * An interface through which a transport plugin interacts with the rest of
  * the application.
@@ -22,7 +25,17 @@ public interface PluginCallback {
 	TransportProperties getLocalProperties();
 
 	/**
-	 * Merges the given settings with the plugin's settings
+	 * Returns the plugin's remote transport properties.
+	 */
+	Map<ContactId, TransportProperties> getRemoteProperties();
+
+	/**
+	 * Returns the plugin's remote transport properties for the given contact.
+	 */
+	TransportProperties getRemoteProperties(ContactId c);
+
+	/**
+	 * Merges the given settings with the namespaced settings
 	 */
 	void mergeSettings(Settings s);
 
@@ -32,12 +45,34 @@ public interface PluginCallback {
 	void mergeLocalProperties(TransportProperties p);
 
 	/**
-	 * Signals that the transport is enabled.
+	 * Presents the user with a choice among two or more named options and
+	 * returns the user's response. The message may consist of a translatable
+	 * format string and arguments.
+	 *
+	 * @return an index into the array of options indicating the user's choice,
+	 * or -1 if the user cancelled the choice.
+	 */
+	int showChoice(String[] options, String... message);
+
+	/**
+	 * Asks the user to confirm an action and returns the user's response. The
+	 * message may consist of a translatable format string and arguments.
+	 */
+	boolean showConfirmationMessage(String... message);
+
+	/**
+	 * Shows a message to the user. The message may consist of a translatable
+	 * format string and arguments.
+	 */
+	void showMessage(String... message);
+
+	/**
+	 * Signal that the transport got enabled.
 	 */
 	void transportEnabled();
 
 	/**
-	 * Signals that the transport is disabled.
+	 * Signal that the transport got disabled.
 	 */
 	void transportDisabled();
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/PluginConfig.java

@@ -12,6 +12,4 @@ public interface PluginConfig {
 	Collection<DuplexPluginFactory> getDuplexFactories();
 
 	Collection<SimplexPluginFactory> getSimplexFactories();
-
-	boolean shouldPoll();
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/TransportConnectionWriter.java

@@ -22,6 +22,11 @@ public interface TransportConnectionWriter {
 	 */
 	int getMaxIdleTime();
 
+	/**
+	 * Returns the capacity of the transport connection in bytes.
+	 */
+	long getCapacity();
+
 	/**
 	 * Returns an output stream for writing to the transport connection.
 	 */

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/TransportId.java

@@ -1,23 +1,22 @@
 package org.briarproject.bramble.api.plugin;
 
-import org.briarproject.bramble.util.StringUtils;
+import java.nio.charset.Charset;
 
 /**
- * Type-safe wrapper for a namespaced string that uniquely identifies a
+ * Type-safe wrapper for a string that uniquely identifies a transport plugin.
- * transport plugin.
  */
 public class TransportId {
 
 	/**
-	 * The maximum length of a transport identifier in UTF-8 bytes.
+	 * The maximum length of transport identifier in UTF-8 bytes.
 	 */
-	public static int MAX_TRANSPORT_ID_LENGTH = 100;
+	public static int MAX_TRANSPORT_ID_LENGTH = 64;
 
 	private final String id;
 
 	public TransportId(String id) {
-		int length = StringUtils.toUtf8(id).length;
+		byte[] b = id.getBytes(Charset.forName("UTF-8"));
-		if (length == 0 || length > MAX_TRANSPORT_ID_LENGTH)
+		if (b.length == 0 || b.length > MAX_TRANSPORT_ID_LENGTH)
 			throw new IllegalArgumentException();
 		this.id = id;
 	}

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/duplex/AbstractDuplexTransportConnection.java

@@ -71,6 +71,11 @@ public abstract class AbstractDuplexTransportConnection
 			return plugin.getMaxIdleTime();
 		}
 
+		@Override
+		public long getCapacity() {
+			return Long.MAX_VALUE;
+		}
+
 		@Override
 		public OutputStream getOutputStream() throws IOException {
 			return AbstractDuplexTransportConnection.this.getOutputStream();

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/duplex/DuplexPlugin.java

@@ -1,10 +1,10 @@
 package org.briarproject.bramble.api.plugin.duplex;
 
+import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Plugin;
-import org.briarproject.bramble.api.properties.TransportProperties;
 
 import javax.annotation.Nullable;
 
@@ -15,11 +15,12 @@ import javax.annotation.Nullable;
 public interface DuplexPlugin extends Plugin {
 
 	/**
-	 * Attempts to create and return a connection using the given transport
+	 * Attempts to create and return a connection to the given contact using
-	 * properties. Returns null if a connection cannot be created.
+	 * the current transport and configuration properties. Returns null if a
+	 * connection cannot be created.
 	 */
 	@Nullable
-	DuplexTransportConnection createConnection(TransportProperties p);
+	DuplexTransportConnection createConnection(ContactId c);
 
 	/**
 	 * Returns true if the plugin supports short-range key agreement.

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/duplex/DuplexPluginCallback.java

@@ -5,8 +5,7 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 
 /**
- * An interface through which a duplex plugin interacts with the rest of the
+ * An interface for handling connections created by a duplex transport plugin.
- * application.
  */
 @NotNullByDefault
 public interface DuplexPluginCallback extends PluginCallback {

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/simplex/SimplexPlugin.java

@@ -1,10 +1,10 @@
 package org.briarproject.bramble.api.plugin.simplex;
 
+import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Plugin;
 import org.briarproject.bramble.api.plugin.TransportConnectionReader;
 import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
-import org.briarproject.bramble.api.properties.TransportProperties;
 
 import javax.annotation.Nullable;
 
@@ -15,16 +15,18 @@ import javax.annotation.Nullable;
 public interface SimplexPlugin extends Plugin {
 
 	/**
-	 * Attempts to create and return a reader for the given transport
+	 * Attempts to create and return a reader for the given contact using the
-	 * properties. Returns null if a reader cannot be created.
+	 * current transport and configuration properties. Returns null if a reader
+	 * cannot be created.
 	 */
 	@Nullable
-	TransportConnectionReader createReader(TransportProperties p);
+	TransportConnectionReader createReader(ContactId c);
 
 	/**
-	 * Attempts to create and return a writer for the given transport
+	 * Attempts to create and return a writer for the given contact using the
-	 * properties. Returns null if a writer cannot be created.
+	 * current transport and configuration properties. Returns null if a writer
+	 * cannot be created.
 	 */
 	@Nullable
-	TransportConnectionWriter createWriter(TransportProperties p);
+	TransportConnectionWriter createWriter(ContactId c);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/simplex/SimplexPluginCallback.java

@@ -7,8 +7,8 @@ import org.briarproject.bramble.api.plugin.TransportConnectionReader;
 import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
 
 /**
- * An interface through which a simplex plugin interacts with the rest of the
+ * An interface for handling readers and writers created by a simplex transport
- * application.
+ * plugin.
  */
 @NotNullByDefault
 public interface SimplexPluginCallback extends PluginCallback {

bramble-api/src/main/java/org/briarproject/bramble/api/properties/TransportPropertyManager.java

@@ -15,17 +15,12 @@ public interface TransportPropertyManager {
 	/**
 	 * The unique ID of the transport property client.
 	 */
-	ClientId CLIENT_ID = new ClientId("org.briarproject.bramble.properties");
+	ClientId CLIENT_ID = new ClientId("org.briarproject.briar.properties");
 
 	/**
-	 * The current major version of the transport property client.
+	 * The current version of the transport property client.
 	 */
-	int MAJOR_VERSION = 0;
+	int CLIENT_VERSION = 0;
-
-	/**
-	 * The current minor version of the transport property client.
-	 */
-	int MINOR_VERSION = 0;
 
 	/**
 	 * Stores the given properties received while adding a contact - they will
@@ -42,8 +37,8 @@ public interface TransportPropertyManager {
 
 	/**
 	 * Returns the local transport properties for all transports.
-	 * <p/>
+	 * <br/>
-	 * Read-only.
+	 * TODO: Transaction can be read-only when code is simplified
 	 */
 	Map<TransportId, TransportProperties> getLocalProperties(Transaction txn)
 			throws DbException;

bramble-api/src/main/java/org/briarproject/bramble/api/record/Record.java

@@ -1,36 +0,0 @@
-package org.briarproject.bramble.api.record;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-@Immutable
-@NotNullByDefault
-public class Record {
-
-	public static final int RECORD_HEADER_BYTES = 4;
-	public static final int MAX_RECORD_PAYLOAD_BYTES = 48 * 1024; // 48 KiB
-
-	private final byte protocolVersion, recordType;
-	private final byte[] payload;
-
-	public Record(byte protocolVersion, byte recordType, byte[] payload) {
-		if (payload.length > MAX_RECORD_PAYLOAD_BYTES)
-			throw new IllegalArgumentException();
-		this.protocolVersion = protocolVersion;
-		this.recordType = recordType;
-		this.payload = payload;
-	}
-
-	public byte getProtocolVersion() {
-		return protocolVersion;
-	}
-
-	public byte getRecordType() {
-		return recordType;
-	}
-
-	public byte[] getPayload() {
-		return payload;
-	}
-}

bramble-api/src/main/java/org/briarproject/bramble/api/record/RecordReader.java

@@ -1,20 +0,0 @@
-package org.briarproject.bramble.api.record;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import java.io.EOFException;
-import java.io.IOException;
-
-@NotNullByDefault
-public interface RecordReader {
-
-	/**
-	 * Reads and returns the next record.
-	 *
-	 * @throws EOFException if the end of the stream is reached without reading
-	 * a complete record
-	 */
-	Record readRecord() throws IOException;
-
-	void close() throws IOException;
-}

bramble-api/src/main/java/org/briarproject/bramble/api/record/RecordReaderFactory.java

@@ -1,8 +0,0 @@
-package org.briarproject.bramble.api.record;
-
-import java.io.InputStream;
-
-public interface RecordReaderFactory {
-
-	RecordReader createRecordReader(InputStream in);
-}

bramble-api/src/main/java/org/briarproject/bramble/api/record/RecordWriter.java

@@ -1,15 +0,0 @@
-package org.briarproject.bramble.api.record;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import java.io.IOException;
-
-@NotNullByDefault
-public interface RecordWriter {
-
-	void writeRecord(Record r) throws IOException;
-
-	void flush() throws IOException;
-
-	void close() throws IOException;
-}

bramble-api/src/main/java/org/briarproject/bramble/api/record/RecordWriterFactory.java

@@ -1,8 +0,0 @@
-package org.briarproject.bramble.api.record;
-
-import java.io.OutputStream;
-
-public interface RecordWriterFactory {
-
-	RecordWriter createRecordWriter(OutputStream out);
-}

bramble-api/src/main/java/org/briarproject/bramble/api/reporting/DevConfig.java

@@ -3,14 +3,10 @@ package org.briarproject.bramble.api.reporting;
 import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
-import java.io.File;
-
 @NotNullByDefault
 public interface DevConfig {
 
 	PublicKey getDevPublicKey();
 
 	String getDevOnionAddress();
-
-	File getReportDir();
 }

bramble-api/src/main/java/org/briarproject/bramble/api/reporting/DevReporter.java

@@ -23,6 +23,8 @@ public interface DevReporter {
 
 	/**
 	 * Sends any reports previously stored on disk.
+	 *
+	 * @param reportDir the directory where reports are stored.
 	 */
-	void sendReports();
+	void sendReports(File reportDir);
 }

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

@@ -1,29 +1,19 @@
 package org.briarproject.bramble.api.sync;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.util.StringUtils;
 
 import javax.annotation.concurrent.Immutable;
 
 /**
- * Type-safe wrapper for a namespaced string that uniquely identifies a sync
+ * Wrapper for a name-spaced string that uniquely identifies a sync client.
- * client.
  */
 @Immutable
 @NotNullByDefault
 public class ClientId implements Comparable<ClientId> {
 
-	/**
-	 * The maximum length of a client identifier in UTF-8 bytes.
-	 */
-	public static int MAX_CLIENT_ID_LENGTH = 100;
-
 	private final String id;
 
 	public ClientId(String id) {
-		int length = StringUtils.toUtf8(id).length;
-		if (length == 0 || length > MAX_CLIENT_ID_LENGTH)
-			throw new IllegalArgumentException();
 		this.id = id;
 	}
 

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

@@ -5,43 +5,20 @@ import static org.briarproject.bramble.api.sync.SyncConstants.MAX_GROUP_DESCRIPT
 public class Group {
 
 	public enum Visibility {
-
+		INVISIBLE, // The group is not visible
-		INVISIBLE(0), // The group is not visible
+		VISIBLE, // The group is visible but messages are not shared
-		VISIBLE(1), // The group is visible, messages are accepted but not sent
+		SHARED // The group is visible and messages are shared
-		SHARED(2); // The group is visible, messages are accepted and sent
-
-		private final int value;
-
-		Visibility(int value) {
-			this.value = value;
-		}
-
-		public int getValue() {
-			return value;
-		}
-
-		public static Visibility min(Visibility a, Visibility b) {
-			return a.getValue() < b.getValue() ? a : b;
-		}
 	}
 
-	/**
-	 * The current version of the group format.
-	 */
-	public static final int FORMAT_VERSION = 1;
-
 	private final GroupId id;
 	private final ClientId clientId;
-	private final int majorVersion;
 	private final byte[] descriptor;
 
-	public Group(GroupId id, ClientId clientId, int majorVersion,
+	public Group(GroupId id, ClientId clientId, byte[] descriptor) {
-			byte[] descriptor) {
 		if (descriptor.length > MAX_GROUP_DESCRIPTOR_LENGTH)
 			throw new IllegalArgumentException();
 		this.id = id;
 		this.clientId = clientId;
-		this.majorVersion = majorVersion;
 		this.descriptor = descriptor;
 	}
 
@@ -59,13 +36,6 @@ public class Group {
 		return clientId;
 	}
 
-	/**
-	 * Returns the major version of the client to which the group belongs.
-	 */
-	public int getMajorVersion() {
-		return majorVersion;
-	}
-
 	/**
 	 * Returns the group's descriptor.
 	 */

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

@@ -6,7 +6,7 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 public interface GroupFactory {
 
 	/**
-	 * Creates a group with the given client ID, major version and descriptor.
+	 * Creates a group with the given client ID, client version and descriptor.
 	 */
-	Group createGroup(ClientId c, int majorVersion, byte[] descriptor);
+	Group createGroup(ClientId c, int clientVersion, byte[] descriptor);
 }

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

@@ -5,11 +5,6 @@ import static org.briarproject.bramble.api.sync.SyncConstants.MESSAGE_HEADER_LEN
 
 public class Message {
 
-	/**
-	 * The current version of the message format.
-	 */
-	public static final int FORMAT_VERSION = 1;
-
 	private final MessageId id;
 	private final GroupId groupId;
 	private final long timestamp;

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

@@ -7,7 +7,5 @@ public interface MessageFactory {
 
 	Message createMessage(GroupId g, long timestamp, byte[] body);
 
-	Message createMessage(byte[] raw);
-
 	Message createMessage(MessageId m, byte[] raw);
 }

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

@@ -16,13 +16,7 @@ public class MessageId extends UniqueId {
 	/**
 	 * Label for hashing messages to calculate their identifiers.
 	 */
-	public static final String ID_LABEL = "org.briarproject.bramble/MESSAGE_ID";
+	public static final String LABEL = "org.briarproject.bramble/MESSAGE_ID";
-
-	/**
-	 * Label for hashing blocks of messages.
-	 */
-	public static final String BLOCK_LABEL =
-			"org.briarproject.bramble/MESSAGE_BLOCK";
 
 	public MessageId(byte[] id) {
 		super(id);

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

@@ -5,7 +5,7 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import java.io.IOException;
 
 @NotNullByDefault
-public interface SyncRecordReader {
+public interface RecordReader {
 
 	boolean eof() throws IOException;
 

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

@@ -5,7 +5,7 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import java.io.InputStream;
 
 @NotNullByDefault
-public interface SyncRecordReaderFactory {
+public interface RecordReaderFactory {
 
-	SyncRecordReader createRecordReader(InputStream in);
+	RecordReader createRecordReader(InputStream in);
 }

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

@@ -5,7 +5,7 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import java.io.IOException;
 
 @NotNullByDefault
-public interface SyncRecordWriter {
+public interface RecordWriter {
 
 	void writeAck(Ack a) throws IOException;
 

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

@@ -5,7 +5,7 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import java.io.OutputStream;
 
 @NotNullByDefault
-public interface SyncRecordWriterFactory {
+public interface RecordWriterFactory {
 
-	SyncRecordWriter createRecordWriter(OutputStream out);
+	RecordWriter createRecordWriter(OutputStream out);
 }

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

@@ -2,8 +2,6 @@ package org.briarproject.bramble.api.sync;
 
 import org.briarproject.bramble.api.UniqueId;
 
-import static org.briarproject.bramble.api.record.Record.MAX_RECORD_PAYLOAD_BYTES;
-
 public interface SyncConstants {
 
 	/**
@@ -12,8 +10,16 @@ public interface SyncConstants {
 	byte PROTOCOL_VERSION = 0;
 
 	/**
-	 * The maximum length of a group descriptor in bytes.
+	 * The length of the record header in bytes.
 	 */
+	int RECORD_HEADER_LENGTH = 4;
+
+	/**
+	 * The maximum length of the record payload in bytes.
+	 */
+	int MAX_RECORD_PAYLOAD_LENGTH = 48 * 1024; // 48 KiB
+
+	/** The maximum length of a group descriptor in bytes. */
 	int MAX_GROUP_DESCRIPTOR_LENGTH = 16 * 1024; // 16 KiB
 
 	/**
@@ -34,5 +40,5 @@ public interface SyncConstants {
 	/**
 	 * The maximum number of message IDs in an ack, offer or request record.
 	 */
-	int MAX_MESSAGE_IDS = MAX_RECORD_PAYLOAD_BYTES / UniqueId.LENGTH;
+	int MAX_MESSAGE_IDS = MAX_RECORD_PAYLOAD_LENGTH / UniqueId.LENGTH;
 }

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

@@ -2,9 +2,9 @@ package org.briarproject.bramble.api.sync;
 
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.transport.StreamWriter;
 
 import java.io.InputStream;
+import java.io.OutputStream;
 
 @NotNullByDefault
 public interface SyncSessionFactory {
@@ -12,8 +12,8 @@ public interface SyncSessionFactory {
 	SyncSession createIncomingSession(ContactId c, InputStream in);
 
 	SyncSession createSimplexOutgoingSession(ContactId c, int maxLatency,
-			StreamWriter streamWriter);
+			OutputStream out);
 
 	SyncSession createDuplexOutgoingSession(ContactId c, int maxLatency,
-			int maxIdleTime, StreamWriter streamWriter);
+			int maxIdleTime, OutputStream out);
 }

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

@@ -3,7 +3,6 @@ package org.briarproject.bramble.api.sync;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.Transaction;
-import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 /**
@@ -34,20 +33,15 @@ public interface ValidationManager {
 	}
 
 	/**
-	 * Registers the message validator for the given client. This method
+	 * Sets the message validator for the given client.
-	 * should be called before {@link LifecycleManager#startServices(String)}.
 	 */
-	void registerMessageValidator(ClientId c, int majorVersion,
+	void registerMessageValidator(ClientId c, MessageValidator v);
-			MessageValidator v);
 
 	/**
-	 * Registers the incoming message hook for the given client. The hook will
+	 * Sets the incoming message hook for the given client. The hook will be
-	 * be called once for each incoming message that passes validation. This
+	 * called once for each incoming message that passes validation.
-	 * method should be called before
-	 * {@link LifecycleManager#startServices(String)}.
 	 */
-	void registerIncomingMessageHook(ClientId c, int majorVersion,
+	void registerIncomingMessageHook(ClientId c, IncomingMessageHook hook);
-			IncomingMessageHook hook);
 
 	interface MessageValidator {
 

bramble-api/src/main/java/org/briarproject/bramble/api/system/Clock.java

@@ -7,12 +7,12 @@ package org.briarproject.bramble.api.system;
 public interface Clock {
 
 	/**
-	 * @see System#currentTimeMillis()
+	 * @see {@link System#currentTimeMillis()}
 	 */
 	long currentTimeMillis();
 
 	/**
-	 * @see Thread#sleep(long)
+	 * @see {@link Thread#sleep(long)}
 	 */
 	void sleep(long milliseconds) throws InterruptedException;
 }

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

@@ -6,8 +6,6 @@ import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.plugin.TransportId;
 
-import java.util.Map;
-
 import javax.annotation.Nullable;
 
 /**
@@ -18,30 +16,12 @@ public interface KeyManager {
 
 	/**
 	 * Informs the key manager that a new contact has been added. Derives and
-	 * stores a set of transport keys for communicating with the contact over
+	 * stores transport keys for communicating with the contact.
-	 * each transport and returns the key set IDs.
-	 * <p/>
 	 * {@link StreamContext StreamContexts} for the contact can be created
 	 * after this method has returned.
-	 *
-	 * @param alice true if the local party is Alice
-	 * @param active whether the derived keys can be used for outgoing streams
 	 */
-	Map<TransportId, KeySetId> addContact(Transaction txn, ContactId c,
+	void addContact(Transaction txn, ContactId c, SecretKey master,
-			SecretKey master, long timestamp, boolean alice, boolean active)
+			long timestamp, boolean alice) throws DbException;
-			throws DbException;
-
-	/**
-	 * Marks the given transport keys as usable for outgoing streams.
-	 */
-	void activateKeys(Transaction txn, Map<TransportId, KeySetId> keys)
-			throws DbException;
-
-	/**
-	 * Returns true if we have keys that can be used for outgoing streams to
-	 * the given contact over the given transport.
-	 */
-	boolean canSendOutgoingStreams(ContactId c, TransportId t);
 
 	/**
 	 * Returns a {@link StreamContext} for sending a stream to the given

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

@@ -1,47 +0,0 @@
-package org.briarproject.bramble.api.transport;
-
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-/**
- * A set of transport keys for communicating with a contact.
- */
-@Immutable
-@NotNullByDefault
-public class KeySet {
-
-	private final KeySetId keySetId;
-	private final ContactId contactId;
-	private final TransportKeys transportKeys;
-
-	public KeySet(KeySetId keySetId, ContactId contactId,
-			TransportKeys transportKeys) {
-		this.keySetId = keySetId;
-		this.contactId = contactId;
-		this.transportKeys = transportKeys;
-	}
-
-	public KeySetId getKeySetId() {
-		return keySetId;
-	}
-
-	public ContactId getContactId() {
-		return contactId;
-	}
-
-	public TransportKeys getTransportKeys() {
-		return transportKeys;
-	}
-
-	@Override
-	public int hashCode() {
-		return keySetId.hashCode();
-	}
-
-	@Override
-	public boolean equals(Object o) {
-		return o instanceof KeySet && keySetId.equals(((KeySet) o).keySetId);
-	}
-}

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

@@ -1,36 +0,0 @@
-package org.briarproject.bramble.api.transport;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-/**
- * Type-safe wrapper for an integer that uniquely identifies a set of transport
- * keys within the scope of the local device.
- * <p/>
- * Key sets created on a given device must have increasing identifiers.
- */
-@Immutable
-@NotNullByDefault
-public class KeySetId {
-
-	private final int id;
-
-	public KeySetId(int id) {
-		this.id = id;
-	}
-
-	public int getInt() {
-		return id;
-	}
-
-	@Override
-	public int hashCode() {
-		return id;
-	}
-
-	@Override
-	public boolean equals(Object o) {
-		return o instanceof KeySetId && id == ((KeySetId) o).id;
-	}
-}

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

@@ -10,20 +10,18 @@ public class OutgoingKeys {
 
 	private final SecretKey tagKey, headerKey;
 	private final long rotationPeriod, streamCounter;
-	private final boolean active;
 
 	public OutgoingKeys(SecretKey tagKey, SecretKey headerKey,
-			long rotationPeriod, boolean active) {
+			long rotationPeriod) {
-		this(tagKey, headerKey, rotationPeriod, 0, active);
+		this(tagKey, headerKey, rotationPeriod, 0);
 	}
 
 	public OutgoingKeys(SecretKey tagKey, SecretKey headerKey,
-			long rotationPeriod, long streamCounter, boolean active) {
+			long rotationPeriod, long streamCounter) {
 		this.tagKey = tagKey;
 		this.headerKey = headerKey;
 		this.rotationPeriod = rotationPeriod;
 		this.streamCounter = streamCounter;
-		this.active = active;
 	}
 
 	public SecretKey getTagKey() {
@@ -41,8 +39,4 @@ public class OutgoingKeys {
 	public long getStreamCounter() {
 		return streamCounter;
 	}
-
-	public boolean isActive() {
-		return active;
-	}
 }

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

@@ -1,19 +0,0 @@
-package org.briarproject.bramble.api.transport;
-
-import java.io.IOException;
-import java.io.OutputStream;
-
-/**
- * An interface for writing data to a transport connection. Data will be
- * encrypted and authenticated before being written to the connection.
- */
-public interface StreamWriter {
-
-	OutputStream getOutputStream();
-
-	/**
-	 * Sends the end of stream marker, informing the recipient that no more
-	 * data will be sent. The connection is flushed but not closed.
-	 */
-	void sendEndOfStream() throws IOException;
-}

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

@@ -12,12 +12,12 @@ public interface StreamWriterFactory {
 	 * Creates an {@link OutputStream OutputStream} for writing to a
 	 * transport stream
 	 */
-	StreamWriter createStreamWriter(OutputStream out, StreamContext ctx);
+	OutputStream createStreamWriter(OutputStream out, StreamContext ctx);
 
 	/**
 	 * Creates an {@link OutputStream OutputStream} for writing to a contact
 	 * exchange stream.
 	 */
-	StreamWriter createContactExchangeStreamWriter(OutputStream out,
+	OutputStream createContactExchangeStreamWriter(OutputStream out,
 			SecretKey headerKey);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/ui/UiCallback.java

@@ -0,0 +1,26 @@
+package org.briarproject.bramble.api.ui;
+
+public interface UiCallback {
+
+	/**
+	 * Presents the user with a choice among two or more named options and
+	 * returns the user's response. The message may consist of a translatable
+	 * format string and arguments.
+	 *
+	 * @return an index into the array of options indicating the user's choice,
+	 * or -1 if the user cancelled the choice.
+	 */
+	int showChoice(String[] options, String... message);
+
+	/**
+	 * Asks the user to confirm an action and returns the user's response. The
+	 * message may consist of a translatable format string and arguments.
+	 */
+	boolean showConfirmationMessage(String... message);
+
+	/**
+	 * Shows a message to the user. The message may consist of a translatable
+	 * format string and arguments.
+	 */
+	void showMessage(String... message);
+}

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

@@ -1,50 +0,0 @@
-package org.briarproject.bramble.api.versioning;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.sync.ClientId;
-
-import javax.annotation.concurrent.Immutable;
-
-@Immutable
-@NotNullByDefault
-public class ClientMajorVersion implements Comparable<ClientMajorVersion> {
-
-	private final ClientId clientId;
-	private final int majorVersion;
-
-	public ClientMajorVersion(ClientId clientId, int majorVersion) {
-		this.clientId = clientId;
-		this.majorVersion = majorVersion;
-	}
-
-	public ClientId getClientId() {
-		return clientId;
-	}
-
-	public int getMajorVersion() {
-		return majorVersion;
-	}
-
-	@Override
-	public boolean equals(Object o) {
-		if (o instanceof ClientMajorVersion) {
-			ClientMajorVersion cv = (ClientMajorVersion) o;
-			return clientId.equals(cv.clientId)
-					&& majorVersion == cv.majorVersion;
-		}
-		return false;
-	}
-
-	@Override
-	public int hashCode() {
-		return (clientId.hashCode() << 16) + majorVersion;
-	}
-
-	@Override
-	public int compareTo(ClientMajorVersion cv) {
-		int compare = clientId.compareTo(cv.clientId);
-		if (compare != 0) return compare;
-		return majorVersion - cv.majorVersion;
-	}
-}
-

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

@@ -1,45 +0,0 @@
-package org.briarproject.bramble.api.versioning;
-
-import org.briarproject.bramble.api.contact.Contact;
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.db.Transaction;
-import org.briarproject.bramble.api.lifecycle.LifecycleManager;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.sync.ClientId;
-import org.briarproject.bramble.api.sync.Group.Visibility;
-
-@NotNullByDefault
-public interface ClientVersioningManager {
-
-	/**
-	 * The unique ID of the versioning client.
-	 */
-	ClientId CLIENT_ID = new ClientId("org.briarproject.bramble.versioning");
-
-	/**
-	 * The current major version of the versioning client.
-	 */
-	int MAJOR_VERSION = 0;
-
-	/**
-	 * Registers a client that will be advertised to contacts. The hook will
-	 * be called when the visibility of the client changes. This method should
-	 * be called before {@link LifecycleManager#startServices(String)}.
-	 */
-	void registerClient(ClientId clientId, int majorVersion, int minorVersion,
-			ClientVersioningHook hook);
-
-	/**
-	 * Returns the visibility of the given client with respect to the given
-	 * contact.
-	 */
-	Visibility getClientVisibility(Transaction txn, ContactId contactId,
-			ClientId clientId, int majorVersion) throws DbException;
-
-	interface ClientVersioningHook {
-
-		void onClientVisibilityChanging(Transaction txn, Contact c,
-				Visibility v) throws DbException;
-	}
-}

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

@@ -9,40 +9,25 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.Socket;
-import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 
-import static java.util.logging.Level.WARNING;
-
 @NotNullByDefault
 public class IoUtils {
 
-	private static final Logger LOG = Logger.getLogger(IoUtils.class.getName());
-
 	public static void deleteFileOrDir(File f) {
 		if (f.isFile()) {
-			delete(f);
+			f.delete();
 		} else if (f.isDirectory()) {
 			File[] children = f.listFiles();
-			if (children == null) {
+			if (children != null)
-				if (LOG.isLoggable(WARNING)) {
-					LOG.warning("Could not list files in "
-							+ f.getAbsolutePath());
-				}
-			} else {
 				for (File child : children) deleteFileOrDir(child);
-			}
+			f.delete();
-			delete(f);
 		}
 	}
 
-	private static void delete(File f) {
+	public static void copyAndClose(InputStream in, OutputStream out)
-		if (!f.delete() && LOG.isLoggable(WARNING))
+			throws IOException {
-			LOG.warning("Could not delete " + f.getAbsolutePath());
-	}
-
-	public static void copyAndClose(InputStream in, OutputStream out) {
 		byte[] buf = new byte[4096];
 		try {
 			while (true) {

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

@@ -22,6 +22,19 @@ public class OsUtils {
 		return os != null && os.contains("Mac OS");
 	}
 
+	public static boolean isMacLeopardOrNewer() {
+		if (!isMac() || version == null) return false;
+		try {
+			String[] v = version.split("\\.");
+			if (v.length != 3) return false;
+			int major = Integer.parseInt(v[0]);
+			int minor = Integer.parseInt(v[1]);
+			return major >= 10 && minor >= 5;
+		} catch (NumberFormatException e) {
+			return false;
+		}
+	}
+
 	public static boolean isLinux() {
 		return os != null && os.contains("Linux") && !isAndroid();
 	}

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

@@ -146,6 +146,14 @@ public class StringUtils {
 		return s.toString();
 	}
 
+	public static String ipToString(int ip) {
+		int ip1 = ip & 0xFF;
+		int ip2 = (ip >> 8) & 0xFF;
+		int ip3 = (ip >> 16) & 0xFF;
+		int ip4 = (ip >> 24) & 0xFF;
+		return ip1 + "." + ip2 + "." + ip3 + "." + ip4;
+	}
+
 	public static String getRandomString(int length) {
 		char[] c = new char[length];
 		for (int i = 0; i < length; i++)

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

@@ -5,8 +5,6 @@ import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.identity.LocalAuthor;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.sync.ClientId;
 import org.briarproject.bramble.api.sync.Group;
 import org.briarproject.bramble.api.sync.GroupId;
@@ -18,18 +16,13 @@ import java.io.File;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
 import java.util.Random;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import static org.briarproject.bramble.api.identity.Author.FORMAT_VERSION;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
-import static org.briarproject.bramble.api.plugin.TransportId.MAX_TRANSPORT_ID_LENGTH;
-import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MAX_PROPERTY_LENGTH;
-import static org.briarproject.bramble.api.sync.ClientId.MAX_CLIENT_ID_LENGTH;
 import static org.briarproject.bramble.api.sync.SyncConstants.MAX_GROUP_DESCRIPTOR_LENGTH;
 import static org.briarproject.bramble.api.sync.SyncConstants.MAX_MESSAGE_BODY_LENGTH;
 import static org.briarproject.bramble.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
@@ -61,33 +54,6 @@ public class TestUtils {
 		return getRandomBytes(UniqueId.LENGTH);
 	}
 
-	public static ClientId getClientId() {
-		return new ClientId(getRandomString(MAX_CLIENT_ID_LENGTH));
-	}
-
-	public static TransportId getTransportId() {
-		return new TransportId(getRandomString(MAX_TRANSPORT_ID_LENGTH));
-	}
-
-	public static TransportProperties getTransportProperties(int number) {
-		TransportProperties tp = new TransportProperties();
-		for (int i = 0; i < number; i++) {
-			tp.put(getRandomString(1 + random.nextInt(MAX_PROPERTY_LENGTH)),
-					getRandomString(1 + random.nextInt(MAX_PROPERTY_LENGTH))
-			);
-		}
-		return tp;
-	}
-
-	public static Map<TransportId, TransportProperties> getTransportPropertiesMap(
-			int number) {
-		Map<TransportId, TransportProperties> map = new HashMap<>();
-		for (int i = 0; i < number; i++) {
-			map.put(getTransportId(), getTransportProperties(number));
-		}
-		return map;
-	}
-
 	public static SecretKey getSecretKey() {
 		return new SecretKey(getRandomBytes(SecretKey.LENGTH));
 	}
@@ -117,16 +83,15 @@ public class TestUtils {
 		return new Author(id, FORMAT_VERSION, name, publicKey);
 	}
 
-	public static Group getGroup(ClientId clientId, int majorVersion) {
+	public static Group getGroup(ClientId clientId) {
 		int descriptorLength = 1 + random.nextInt(MAX_GROUP_DESCRIPTOR_LENGTH);
-		return getGroup(clientId, majorVersion, descriptorLength);
+		return getGroup(clientId, descriptorLength);
 	}
 
-	public static Group getGroup(ClientId clientId, int majorVersion,
+	public static Group getGroup(ClientId clientId, int descriptorLength) {
-			int descriptorLength) {
 		GroupId groupId = new GroupId(getRandomId());
 		byte[] descriptor = getRandomBytes(descriptorLength);
-		return new Group(groupId, clientId, majorVersion, descriptor);
+		return new Group(groupId, clientId, descriptor);
 	}
 
 	public static Message getMessage(GroupId groupId) {

bramble-core/build.gradle

@@ -2,7 +2,6 @@ apply plugin: 'java-library'
 sourceCompatibility = 1.8
 targetCompatibility = 1.8
 
-apply plugin: 'ru.vyarus.animalsniffer'
 apply plugin: 'net.ltgt.apt'
 apply plugin: 'idea'
 apply plugin: 'witness'
@@ -27,13 +26,12 @@ dependencies {
 	testImplementation "org.hamcrest:hamcrest-core:1.3"
 
 	testApt 'com.google.dagger:dagger-compiler:2.0.2'
-
-	signature 'org.codehaus.mojo.signature:java16:1.1@signature'
 }
 
 dependencyVerification {
 	verify = [
 			'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
+			'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
 			'com.google.dagger:dagger-compiler:2.0.2:dagger-compiler-2.0.2.jar:b74bc9de063dd4c6400b232231f2ef5056145b8fbecbf5382012007dd1c071b3',
 			'com.google.dagger:dagger-producers:2.0-beta:dagger-producers-2.0-beta.jar:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
 			'com.google.dagger:dagger:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
@@ -47,9 +45,6 @@ dependencyVerification {
 			'org.apache.ant:ant:1.9.4:ant-1.9.4.jar:649ae0730251de07b8913f49286d46bba7b92d47c5f332610aa426c4f02161d8',
 			'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
 			'org.bitlet:weupnp:0.1.4:weupnp-0.1.4.jar:88df7e6504929d00bdb832863761385c68ab92af945b04f0770b126270a444fb',
-			'org.codehaus.mojo.signature:java16:1.1:java16-1.1.signature:53799223a2c98dba2d0add810bed76315460df285c69e4f397ae6098f87dd619',
-			'org.codehaus.mojo:animal-sniffer-ant-tasks:1.16:animal-sniffer-ant-tasks-1.16.jar:890040976fbe2d584619a6a61b1fd2e925b3b5eb342a85eb2762c467c0d64e90',
-			'org.codehaus.mojo:animal-sniffer:1.16:animal-sniffer-1.16.jar:72be8bcc226ba43b937c722a08a07852bfa1b11400089265d5df0ee7b38b1d52',
 			'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
 			'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
 			'org.hsqldb:hsqldb:2.3.5:hsqldb-2.3.5.jar:6676a6977ac98997a80f827ddbd3fe8ca1e0853dad1492512135fd1a222ccfad',
@@ -58,7 +53,6 @@ dependencyVerification {
 			'org.jmock:jmock-testjar:2.8.2:jmock-testjar-2.8.2.jar:8900860f72c474e027cf97fe78dcbf154a1aa7fc62b6845c5fb4e4f3c7bc8760',
 			'org.jmock:jmock:2.8.2:jmock-2.8.2.jar:6c73cb4a2e6dbfb61fd99c9a768539c170ab6568e57846bd60dbf19596b65b16',
 			'org.objenesis:objenesis:2.1:objenesis-2.1.jar:c74330cc6b806c804fd37e74487b4fe5d7c2750c5e15fbc6efa13bdee1bdef80',
-			'org.ow2.asm:asm-all:5.2:asm-all-5.2.jar:7fbffbc1db3422e2101689fd88df8384b15817b52b9b2b267b9f6d2511dc198d',
 			'org.ow2.asm:asm:5.0.4:asm-5.0.4.jar:896618ed8ae62702521a78bc7be42b7c491a08e6920a15f89a3ecdec31e9a220',
 			'org.whispersystems:curve25519-java:0.4.1:curve25519-java-0.4.1.jar:7dd659d8822c06c3aea1a47f18fac9e5761e29cab8100030b877db445005f03e',
 	]
@@ -75,3 +69,8 @@ task jarTest(type: Jar, dependsOn: testClasses) {
 artifacts {
 	testOutput jarTest
 }
+
+// If a Java 6 JRE is available, check we're not using any Java 7 or 8 APIs
+tasks.withType(JavaCompile) {
+	useJava6StandardLibrary(it)
+}

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

@@ -1,23 +1,21 @@
 package org.briarproject.bramble;
 
 import org.briarproject.bramble.contact.ContactModule;
-import org.briarproject.bramble.crypto.CryptoExecutorModule;
+import org.briarproject.bramble.crypto.CryptoModule;
 import org.briarproject.bramble.db.DatabaseExecutorModule;
 import org.briarproject.bramble.identity.IdentityModule;
 import org.briarproject.bramble.lifecycle.LifecycleModule;
 import org.briarproject.bramble.plugin.PluginModule;
 import org.briarproject.bramble.properties.PropertiesModule;
-import org.briarproject.bramble.reporting.ReportingModule;
 import org.briarproject.bramble.sync.SyncModule;
 import org.briarproject.bramble.system.SystemModule;
 import org.briarproject.bramble.transport.TransportModule;
-import org.briarproject.bramble.versioning.VersioningModule;
 
 public interface BrambleCoreEagerSingletons {
 
 	void inject(ContactModule.EagerSingletons init);
 
-	void inject(CryptoExecutorModule.EagerSingletons init);
+	void inject(CryptoModule.EagerSingletons init);
 
 	void inject(DatabaseExecutorModule.EagerSingletons init);
 
@@ -29,13 +27,9 @@ public interface BrambleCoreEagerSingletons {
 
 	void inject(PropertiesModule.EagerSingletons init);
 
-	void inject(ReportingModule.EagerSingletons init);
-
 	void inject(SyncModule.EagerSingletons init);
 
 	void inject(SystemModule.EagerSingletons init);
 
 	void inject(TransportModule.EagerSingletons init);
-
-	void inject(VersioningModule.EagerSingletons init);
 }

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

@@ -2,7 +2,6 @@ package org.briarproject.bramble;
 
 import org.briarproject.bramble.client.ClientModule;
 import org.briarproject.bramble.contact.ContactModule;
-import org.briarproject.bramble.crypto.CryptoExecutorModule;
 import org.briarproject.bramble.crypto.CryptoModule;
 import org.briarproject.bramble.data.DataModule;
 import org.briarproject.bramble.db.DatabaseExecutorModule;
@@ -13,7 +12,6 @@ import org.briarproject.bramble.keyagreement.KeyAgreementModule;
 import org.briarproject.bramble.lifecycle.LifecycleModule;
 import org.briarproject.bramble.plugin.PluginModule;
 import org.briarproject.bramble.properties.PropertiesModule;
-import org.briarproject.bramble.record.RecordModule;
 import org.briarproject.bramble.reliability.ReliabilityModule;
 import org.briarproject.bramble.reporting.ReportingModule;
 import org.briarproject.bramble.settings.SettingsModule;
@@ -21,7 +19,6 @@ import org.briarproject.bramble.socks.SocksModule;
 import org.briarproject.bramble.sync.SyncModule;
 import org.briarproject.bramble.system.SystemModule;
 import org.briarproject.bramble.transport.TransportModule;
-import org.briarproject.bramble.versioning.VersioningModule;
 
 import dagger.Module;
 
@@ -29,7 +26,6 @@ import dagger.Module;
 		ClientModule.class,
 		ContactModule.class,
 		CryptoModule.class,
-		CryptoExecutorModule.class,
 		DataModule.class,
 		DatabaseModule.class,
 		DatabaseExecutorModule.class,
@@ -39,30 +35,26 @@ import dagger.Module;
 		LifecycleModule.class,
 		PluginModule.class,
 		PropertiesModule.class,
-		RecordModule.class,
 		ReliabilityModule.class,
 		ReportingModule.class,
 		SettingsModule.class,
 		SocksModule.class,
 		SyncModule.class,
 		SystemModule.class,
-		TransportModule.class,
+		TransportModule.class
-		VersioningModule.class
 })
 public class BrambleCoreModule {
 
 	public static void initEagerSingletons(BrambleCoreEagerSingletons c) {
 		c.inject(new ContactModule.EagerSingletons());
-		c.inject(new CryptoExecutorModule.EagerSingletons());
+		c.inject(new CryptoModule.EagerSingletons());
 		c.inject(new DatabaseExecutorModule.EagerSingletons());
 		c.inject(new IdentityModule.EagerSingletons());
 		c.inject(new LifecycleModule.EagerSingletons());
 		c.inject(new PluginModule.EagerSingletons());
 		c.inject(new PropertiesModule.EagerSingletons());
-		c.inject(new ReportingModule.EagerSingletons());
 		c.inject(new SyncModule.EagerSingletons());
 		c.inject(new SystemModule.EagerSingletons());
 		c.inject(new TransportModule.EagerSingletons());
-		c.inject(new VersioningModule.EagerSingletons());
 	}
 }

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

@@ -18,8 +18,6 @@ import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorFactory;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageFactory;
@@ -39,8 +37,6 @@ import javax.inject.Inject;
 import static org.briarproject.bramble.api.identity.Author.FORMAT_VERSION;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
-import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MAX_PROPERTIES_PER_TRANSPORT;
-import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MAX_PROPERTY_LENGTH;
 import static org.briarproject.bramble.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
 import static org.briarproject.bramble.util.ValidationUtils.checkLength;
 import static org.briarproject.bramble.util.ValidationUtils.checkSize;
@@ -328,20 +324,6 @@ class ClientHelperImpl implements ClientHelper {
 		}
 	}
 
-	@Override
-	public BdfDictionary toDictionary(TransportProperties transportProperties) {
-		return new BdfDictionary(transportProperties);
-	}
-
-	@Override
-	public BdfDictionary toDictionary(
-			Map<TransportId, TransportProperties> map) {
-		BdfDictionary d = new BdfDictionary();
-		for (Entry<TransportId, TransportProperties> e : map.entrySet())
-			d.put(e.getKey().getString(), new BdfDictionary(e.getValue()));
-		return d;
-	}
-
 	@Override
 	public BdfList toList(byte[] b, int off, int len) throws FormatException {
 		ByteArrayInputStream in = new ByteArrayInputStream(b, off, len);
@@ -381,10 +363,9 @@ class ClientHelperImpl implements ClientHelper {
 	}
 
 	@Override
-	public void verifySignature(byte[] signature, String label, BdfList signed,
+	public void verifySignature(String label, byte[] sig, byte[] publicKey,
-			byte[] publicKey) throws FormatException, GeneralSecurityException {
+			BdfList signed) throws FormatException, GeneralSecurityException {
-		if (!crypto.verifySignature(signature, label, toByteArray(signed),
+		if (!crypto.verify(label, toByteArray(signed), publicKey, sig)) {
-				publicKey)) {
 			throw new GeneralSecurityException("Invalid signature");
 		}
 	}
@@ -401,33 +382,4 @@ class ClientHelperImpl implements ClientHelper {
 		checkLength(publicKey, 1, MAX_PUBLIC_KEY_LENGTH);
 		return authorFactory.createAuthor(formatVersion, name, publicKey);
 	}
-
-	@Override
-	public TransportProperties parseAndValidateTransportProperties(
-			BdfDictionary properties) throws FormatException {
-		checkSize(properties, 0, MAX_PROPERTIES_PER_TRANSPORT);
-		TransportProperties p = new TransportProperties();
-		for (String key : properties.keySet()) {
-			checkLength(key, 1, MAX_PROPERTY_LENGTH);
-			String value = properties.getString(key);
-			checkLength(value, 1, MAX_PROPERTY_LENGTH);
-			p.put(key, value);
-		}
-		return p;
-	}
-
-	@Override
-	public Map<TransportId, TransportProperties> parseAndValidateTransportPropertiesMap(
-			BdfDictionary properties) throws FormatException {
-		Map<TransportId, TransportProperties> tpMap = new HashMap<>();
-		for (String key : properties.keySet()) {
-			TransportId transportId = new TransportId(key);
-			TransportProperties transportProperties =
-					parseAndValidateTransportProperties(
-							properties.getDictionary(key));
-			tpMap.put(transportId, transportProperties);
-		}
-		return tpMap;
-	}
-
 }

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

@@ -32,25 +32,25 @@ class ContactGroupFactoryImpl implements ContactGroupFactory {
 	}
 
 	@Override
-	public Group createLocalGroup(ClientId clientId, int majorVersion) {
+	public Group createLocalGroup(ClientId clientId, int clientVersion) {
-		return groupFactory.createGroup(clientId, majorVersion,
+		return groupFactory.createGroup(clientId, clientVersion,
 				LOCAL_GROUP_DESCRIPTOR);
 	}
 
 	@Override
-	public Group createContactGroup(ClientId clientId, int majorVersion,
+	public Group createContactGroup(ClientId clientId, int clientVersion,
 			Contact contact) {
 		AuthorId local = contact.getLocalAuthorId();
 		AuthorId remote = contact.getAuthor().getId();
 		byte[] descriptor = createGroupDescriptor(local, remote);
-		return groupFactory.createGroup(clientId, majorVersion, descriptor);
+		return groupFactory.createGroup(clientId, clientVersion, descriptor);
 	}
 
 	@Override
-	public Group createContactGroup(ClientId clientId, int majorVersion,
+	public Group createContactGroup(ClientId clientId, int clientVersion,
 			AuthorId authorId1, AuthorId authorId2) {
 		byte[] descriptor = createGroupDescriptor(authorId1, authorId2);
-		return groupFactory.createGroup(clientId, majorVersion, descriptor);
+		return groupFactory.createGroup(clientId, clientVersion, descriptor);
 	}
 
 	private byte[] createGroupDescriptor(AuthorId local, AuthorId remote) {

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

@@ -1,20 +1,23 @@
 package org.briarproject.bramble.contact;
 
 import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.client.ClientHelper;
 import org.briarproject.bramble.api.contact.ContactExchangeListener;
 import org.briarproject.bramble.api.contact.ContactExchangeTask;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.SecretKey;
-import org.briarproject.bramble.api.data.BdfDictionary;
 import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.data.BdfReader;
+import org.briarproject.bramble.api.data.BdfReaderFactory;
+import org.briarproject.bramble.api.data.BdfWriter;
+import org.briarproject.bramble.api.data.BdfWriterFactory;
 import org.briarproject.bramble.api.db.ContactExistsException;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.identity.AuthorFactory;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
@@ -23,31 +26,30 @@ import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.properties.TransportPropertyManager;
-import org.briarproject.bramble.api.record.Record;
-import org.briarproject.bramble.api.record.RecordReader;
-import org.briarproject.bramble.api.record.RecordReaderFactory;
-import org.briarproject.bramble.api.record.RecordWriter;
-import org.briarproject.bramble.api.record.RecordWriterFactory;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.transport.StreamReaderFactory;
-import org.briarproject.bramble.api.transport.StreamWriter;
 import org.briarproject.bramble.api.transport.StreamWriterFactory;
 
-import java.io.EOFException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.security.GeneralSecurityException;
+import java.util.HashMap;
 import java.util.Map;
+import java.util.Map.Entry;
 import java.util.logging.Logger;
 
 import javax.inject.Inject;
 
+import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.api.contact.RecordTypes.CONTACT_INFO;
+import static org.briarproject.bramble.api.identity.Author.FORMAT_VERSION;
+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_SIGNATURE_LENGTH;
-import static org.briarproject.bramble.util.ValidationUtils.checkLength;
+import static org.briarproject.bramble.api.plugin.TransportId.MAX_TRANSPORT_ID_LENGTH;
-import static org.briarproject.bramble.util.ValidationUtils.checkSize;
+import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MAX_PROPERTIES_PER_TRANSPORT;
+import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MAX_PROPERTY_LENGTH;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
@@ -60,9 +62,9 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 			"org.briarproject.briar.contact/EXCHANGE";
 
 	private final DatabaseComponent db;
-	private final ClientHelper clientHelper;
+	private final AuthorFactory authorFactory;
-	private final RecordReaderFactory recordReaderFactory;
+	private final BdfReaderFactory bdfReaderFactory;
-	private final RecordWriterFactory recordWriterFactory;
+	private final BdfWriterFactory bdfWriterFactory;
 	private final Clock clock;
 	private final ConnectionManager connectionManager;
 	private final ContactManager contactManager;
@@ -79,17 +81,17 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 	private volatile boolean alice;
 
 	@Inject
-	ContactExchangeTaskImpl(DatabaseComponent db, ClientHelper clientHelper,
+	ContactExchangeTaskImpl(DatabaseComponent db,
-			RecordReaderFactory recordReaderFactory,
+			AuthorFactory authorFactory, BdfReaderFactory bdfReaderFactory,
-			RecordWriterFactory recordWriterFactory, Clock clock,
+			BdfWriterFactory bdfWriterFactory, Clock clock,
 			ConnectionManager connectionManager, ContactManager contactManager,
 			TransportPropertyManager transportPropertyManager,
 			CryptoComponent crypto, StreamReaderFactory streamReaderFactory,
 			StreamWriterFactory streamWriterFactory) {
 		this.db = db;
-		this.clientHelper = clientHelper;
+		this.authorFactory = authorFactory;
-		this.recordReaderFactory = recordReaderFactory;
+		this.bdfReaderFactory = bdfReaderFactory;
-		this.recordWriterFactory = recordWriterFactory;
+		this.bdfWriterFactory = bdfWriterFactory;
 		this.clock = clock;
 		this.connectionManager = connectionManager;
 		this.contactManager = contactManager;
@@ -124,18 +126,18 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		} catch (IOException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			listener.contactExchangeFailed();
-			tryToClose(conn);
+			tryToClose(conn, true);
 			return;
 		}
 
 		// Get the local transport properties
-		Map<TransportId, TransportProperties> localProperties;
+		Map<TransportId, TransportProperties> localProperties, remoteProperties;
 		try {
 			localProperties = transportPropertyManager.getLocalProperties();
 		} catch (DbException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			listener.contactExchangeFailed();
-			tryToClose(conn);
+			tryToClose(conn, true);
 			return;
 		}
 
@@ -149,138 +151,158 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		InputStream streamReader =
 				streamReaderFactory.createContactExchangeStreamReader(in,
 						alice ? bobHeaderKey : aliceHeaderKey);
-		RecordReader recordReader =
+		BdfReader r = bdfReaderFactory.createReader(streamReader);
-				recordReaderFactory.createRecordReader(streamReader);
-
 		// Create the writers
-		StreamWriter streamWriter =
+		OutputStream streamWriter =
 				streamWriterFactory.createContactExchangeStreamWriter(out,
 						alice ? aliceHeaderKey : bobHeaderKey);
-		RecordWriter recordWriter =
+		BdfWriter w = bdfWriterFactory.createWriter(streamWriter);
-				recordWriterFactory.createRecordWriter(streamWriter.getOutputStream());
 
 		// Derive the nonces to be signed
 		byte[] aliceNonce = crypto.mac(ALICE_NONCE_LABEL, masterSecret,
 				new byte[] {PROTOCOL_VERSION});
 		byte[] bobNonce = crypto.mac(BOB_NONCE_LABEL, masterSecret,
 				new byte[] {PROTOCOL_VERSION});
-		byte[] localNonce = alice ? aliceNonce : bobNonce;
-		byte[] remoteNonce = alice ? bobNonce : aliceNonce;
 
-		// Sign the nonce
+		// Exchange pseudonyms, signed nonces, and timestamps
-		byte[] localSignature = sign(localAuthor, localNonce);
-
-		// Exchange contact info
 		long localTimestamp = clock.currentTimeMillis();
-		ContactInfo remoteInfo;
+		Author remoteAuthor;
+		long remoteTimestamp;
 		try {
 			if (alice) {
-				sendContactInfo(recordWriter, localAuthor, localProperties,
+				sendPseudonym(w, aliceNonce);
-						localSignature, localTimestamp);
+				sendTimestamp(w, localTimestamp);
-				recordWriter.flush();
+				sendTransportProperties(w, localProperties);
-				remoteInfo = receiveContactInfo(recordReader);
+				w.flush();
+				remoteAuthor = receivePseudonym(r, bobNonce);
+				remoteTimestamp = receiveTimestamp(r);
+				remoteProperties = receiveTransportProperties(r);
 			} else {
-				remoteInfo = receiveContactInfo(recordReader);
+				remoteAuthor = receivePseudonym(r, aliceNonce);
-				sendContactInfo(recordWriter, localAuthor, localProperties,
+				remoteTimestamp = receiveTimestamp(r);
-						localSignature, localTimestamp);
+				remoteProperties = receiveTransportProperties(r);
-				recordWriter.flush();
+				sendPseudonym(w, bobNonce);
+				sendTimestamp(w, localTimestamp);
+				sendTransportProperties(w, localProperties);
+				w.flush();
 			}
-			// Send EOF on the outgoing stream
+			// Close the outgoing stream and expect EOF on the incoming stream
-			streamWriter.sendEndOfStream();
+			w.close();
-			// Skip any remaining records from the incoming stream
+			if (!r.eof()) LOG.warning("Unexpected data at end of connection");
-			try {
+		} catch (GeneralSecurityException | IOException e) {
-				while (true) recordReader.readRecord();
-			} catch (EOFException expected) {
-				LOG.info("End of stream");
-			}
-		} catch (IOException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			listener.contactExchangeFailed();
-			tryToClose(conn);
+			tryToClose(conn, true);
-			return;
-		}
-
-		// Verify the contact's signature
-		if (!verify(remoteInfo.author, remoteNonce, remoteInfo.signature)) {
-			LOG.warning("Invalid signature");
-			listener.contactExchangeFailed();
-			tryToClose(conn);
 			return;
 		}
 
 		// The agreed timestamp is the minimum of the peers' timestamps
-		long timestamp = Math.min(localTimestamp, remoteInfo.timestamp);
+		long timestamp = Math.min(localTimestamp, remoteTimestamp);
 
 		try {
 			// Add the contact
-			ContactId contactId = addContact(remoteInfo.author, timestamp,
+			ContactId contactId = addContact(remoteAuthor, timestamp,
-					remoteInfo.properties);
+					remoteProperties);
 			// Reuse the connection as a transport connection
 			connectionManager.manageOutgoingConnection(contactId, transportId,
 					conn);
 			// Pseudonym exchange succeeded
 			LOG.info("Pseudonym exchange succeeded");
-			listener.contactExchangeSucceeded(remoteInfo.author);
+			listener.contactExchangeSucceeded(remoteAuthor);
 		} catch (ContactExistsException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			tryToClose(conn);
+			tryToClose(conn, true);
-			listener.duplicateContact(remoteInfo.author);
+			listener.duplicateContact(remoteAuthor);
 		} catch (DbException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			tryToClose(conn);
+			tryToClose(conn, true);
 			listener.contactExchangeFailed();
 		}
 	}
 
-	private byte[] sign(LocalAuthor author, byte[] nonce) {
+	private void sendPseudonym(BdfWriter w, byte[] nonce)
-		try {
+			throws GeneralSecurityException, IOException {
-			return crypto.sign(SIGNING_LABEL_EXCHANGE, nonce,
+		// Sign the nonce
-					author.getPrivateKey());
+		byte[] privateKey = localAuthor.getPrivateKey();
-		} catch (GeneralSecurityException e) {
+		byte[] sig = crypto.sign(SIGNING_LABEL_EXCHANGE, nonce, privateKey);
-			throw new AssertionError();
+
+		// Write the name, public key and signature
+		w.writeListStart();
+		w.writeLong(localAuthor.getFormatVersion());
+		w.writeString(localAuthor.getName());
+		w.writeRaw(localAuthor.getPublicKey());
+		w.writeRaw(sig);
+		w.writeListEnd();
+		LOG.info("Sent pseudonym");
+	}
+
+	private Author receivePseudonym(BdfReader r, byte[] nonce)
+			throws GeneralSecurityException, IOException {
+		// Read the format version, name, public key and signature
+		r.readListStart();
+		int formatVersion = (int) r.readLong();
+		if (formatVersion != FORMAT_VERSION) throw new FormatException();
+		String name = r.readString(MAX_AUTHOR_NAME_LENGTH);
+		if (name.isEmpty()) throw new FormatException();
+		byte[] publicKey = r.readRaw(MAX_PUBLIC_KEY_LENGTH);
+		if (publicKey.length == 0) throw new FormatException();
+		byte[] sig = r.readRaw(MAX_SIGNATURE_LENGTH);
+		if (sig.length == 0) throw new FormatException();
+		r.readListEnd();
+		LOG.info("Received pseudonym");
+		// Verify the signature
+		if (!crypto.verify(SIGNING_LABEL_EXCHANGE, nonce, publicKey, sig)) {
+			if (LOG.isLoggable(INFO))
+				LOG.info("Invalid signature");
+			throw new GeneralSecurityException();
 		}
+		return authorFactory.createAuthor(formatVersion, name, publicKey);
 	}
 
-	private boolean verify(Author author, byte[] nonce, byte[] signature) {
+	private void sendTimestamp(BdfWriter w, long timestamp)
-		try {
-			return crypto.verifySignature(signature, SIGNING_LABEL_EXCHANGE,
-					nonce, author.getPublicKey());
-		} catch (GeneralSecurityException e) {
-			return false;
-		}
-	}
-
-	private void sendContactInfo(RecordWriter recordWriter, Author author,
-			Map<TransportId, TransportProperties> properties, byte[] signature,
-			long timestamp) throws IOException {
-		BdfList authorList = clientHelper.toList(author);
-		BdfDictionary props = clientHelper.toDictionary(properties);
-		BdfList payload = BdfList.of(authorList, props, signature, timestamp);
-		recordWriter.writeRecord(new Record(PROTOCOL_VERSION, CONTACT_INFO,
-				clientHelper.toByteArray(payload)));
-		LOG.info("Sent contact info");
-	}
-
-	private ContactInfo receiveContactInfo(RecordReader recordReader)
 			throws IOException {
-		Record record;
+		w.writeLong(timestamp);
-		do {
+		LOG.info("Sent timestamp");
-			record = recordReader.readRecord();
+	}
-			if (record.getProtocolVersion() != PROTOCOL_VERSION)
+
-				throw new FormatException();
+	private long receiveTimestamp(BdfReader r) throws IOException {
-		} while (record.getRecordType() != CONTACT_INFO);
+		long timestamp = r.readLong();
-		LOG.info("Received contact info");
-		BdfList payload = clientHelper.toList(record.getPayload());
-		checkSize(payload, 4);
-		Author author = clientHelper.parseAndValidateAuthor(payload.getList(0));
-		BdfDictionary props = payload.getDictionary(1);
-		Map<TransportId, TransportProperties> properties =
-				clientHelper.parseAndValidateTransportPropertiesMap(props);
-		byte[] signature = payload.getRaw(2);
-		checkLength(signature, 1, MAX_SIGNATURE_LENGTH);
-		long timestamp = payload.getLong(3);
 		if (timestamp < 0) throw new FormatException();
-		return new ContactInfo(author, properties, signature, timestamp);
+		LOG.info("Received timestamp");
+		return timestamp;
+	}
+
+	private void sendTransportProperties(BdfWriter w,
+			Map<TransportId, TransportProperties> local) throws IOException {
+		w.writeListStart();
+		for (Entry<TransportId, TransportProperties> e : local.entrySet())
+			w.writeList(BdfList.of(e.getKey().getString(), e.getValue()));
+		w.writeListEnd();
+	}
+
+	private Map<TransportId, TransportProperties> receiveTransportProperties(
+			BdfReader r) throws IOException {
+		Map<TransportId, TransportProperties> remote = new HashMap<>();
+		r.readListStart();
+		while (!r.hasListEnd()) {
+			r.readListStart();
+			String id = r.readString(MAX_TRANSPORT_ID_LENGTH);
+			if (id.isEmpty()) throw new FormatException();
+			TransportProperties p = new TransportProperties();
+			r.readDictionaryStart();
+			while (!r.hasDictionaryEnd()) {
+				if (p.size() == MAX_PROPERTIES_PER_TRANSPORT)
+					throw new FormatException();
+				String key = r.readString(MAX_PROPERTY_LENGTH);
+				String value = r.readString(MAX_PROPERTY_LENGTH);
+				p.put(key, value);
+			}
+			r.readDictionaryEnd();
+			r.readListEnd();
+			remote.put(new TransportId(id), p);
+		}
+		r.readListEnd();
+		return remote;
 	}
 
 	private ContactId addContact(Author remoteAuthor, long timestamp,
@@ -301,30 +323,13 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		return contactId;
 	}
 
-	private void tryToClose(DuplexTransportConnection conn) {
+	private void tryToClose(DuplexTransportConnection conn, boolean exception) {
 		try {
 			LOG.info("Closing connection");
-			conn.getReader().dispose(true, true);
+			conn.getReader().dispose(exception, true);
-			conn.getWriter().dispose(true);
+			conn.getWriter().dispose(exception);
 		} catch (IOException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 		}
 	}
-
-	private static class ContactInfo {
-
-		private final Author author;
-		private final Map<TransportId, TransportProperties> properties;
-		private final byte[] signature;
-		private final long timestamp;
-
-		private ContactInfo(Author author,
-				Map<TransportId, TransportProperties> properties,
-				byte[] signature, long timestamp) {
-			this.author = author;
-			this.properties = properties;
-			this.signature = signature;
-			this.timestamp = timestamp;
-		}
-	}
 }

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

@@ -27,37 +27,36 @@ class ContactManagerImpl implements ContactManager {
 
 	private final DatabaseComponent db;
 	private final KeyManager keyManager;
-	private final List<ContactHook> hooks;
+	private final List<AddContactHook> addHooks;
+	private final List<RemoveContactHook> removeHooks;
 
 	@Inject
 	ContactManagerImpl(DatabaseComponent db, KeyManager keyManager) {
 		this.db = db;
 		this.keyManager = keyManager;
-		hooks = new CopyOnWriteArrayList<>();
+		addHooks = new CopyOnWriteArrayList<>();
+		removeHooks = new CopyOnWriteArrayList<>();
 	}
 
 	@Override
-	public void registerContactHook(ContactHook hook) {
+	public void registerAddContactHook(AddContactHook hook) {
-		hooks.add(hook);
+		addHooks.add(hook);
+	}
+
+	@Override
+	public void registerRemoveContactHook(RemoveContactHook hook) {
+		removeHooks.add(hook);
 	}
 
 	@Override
 	public ContactId addContact(Transaction txn, Author remote, AuthorId local,
-			SecretKey master, long timestamp, boolean alice, boolean verified,
+			SecretKey master,long timestamp, boolean alice, boolean verified,
 			boolean active) throws DbException {
 		ContactId c = db.addContact(txn, remote, local, verified, active);
-		keyManager.addContact(txn, c, master, timestamp, alice, active);
+		keyManager.addContact(txn, c, master, timestamp, alice);
 		Contact contact = db.getContact(txn, c);
-		for (ContactHook hook : hooks) hook.addingContact(txn, contact);
+		for (AddContactHook hook : addHooks)
-		return c;
+			hook.addingContact(txn, contact);
-	}
-
-	@Override
-	public ContactId addContact(Transaction txn, Author remote, AuthorId local,
-			boolean verified, boolean active) throws DbException {
-		ContactId c = db.addContact(txn, remote, local, verified, active);
-		Contact contact = db.getContact(txn, c);
-		for (ContactHook hook : hooks) hook.addingContact(txn, contact);
 		return c;
 	}
 
@@ -157,7 +156,7 @@ class ContactManagerImpl implements ContactManager {
 	@Override
 	public boolean contactExists(AuthorId remoteAuthorId,
 			AuthorId localAuthorId) throws DbException {
-		boolean exists;
+		boolean exists = false;
 		Transaction txn = db.startTransaction(true);
 		try {
 			exists = contactExists(txn, remoteAuthorId, localAuthorId);
@@ -172,7 +171,8 @@ class ContactManagerImpl implements ContactManager {
 	public void removeContact(Transaction txn, ContactId c)
 			throws DbException {
 		Contact contact = db.getContact(txn, c);
-		for (ContactHook hook : hooks) hook.removingContact(txn, contact);
+		for (RemoveContactHook hook : removeHooks)
+			hook.removingContact(txn, contact);
 		db.removeContact(txn, c);
 	}
 

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

@@ -205,12 +205,12 @@ class CryptoComponentImpl implements CryptoComponent {
 	}
 
 	@Override
-	public boolean verifySignature(byte[] signature, String label,
+	public boolean verify(String label, byte[] signedData, byte[] publicKey,
-			byte[] signed, byte[] publicKey) throws GeneralSecurityException {
+			byte[] signature) throws GeneralSecurityException {
 		PublicKey key = signatureKeyParser.parsePublicKey(publicKey);
 		Signature sig = new EdSignature();
 		sig.initVerify(key);
-		updateSignature(sig, label, signed);
+		updateSignature(sig, label, signedData);
 		return sig.verify(signature);
 	}
 
@@ -262,17 +262,6 @@ class CryptoComponentImpl implements CryptoComponent {
 		return output;
 	}
 
-	@Override
-	public boolean verifyMac(byte[] mac, String label, SecretKey macKey,
-			byte[]... inputs) {
-		byte[] expected = mac(label, macKey, inputs);
-		if (mac.length != expected.length) return false;
-		// Constant-time comparison
-		int cmp = 0;
-		for (int i = 0; i < mac.length; i++) cmp |= mac[i] ^ expected[i];
-		return cmp == 0;
-	}
-
 	@Override
 	public byte[] encryptWithPassword(byte[] input, String password) {
 		AuthenticatedCipher cipher = new XSalsa20Poly1305AuthenticatedCipher();

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

@@ -1,67 +0,0 @@
-package org.briarproject.bramble.crypto;
-
-import org.briarproject.bramble.TimeLoggingExecutor;
-import org.briarproject.bramble.api.crypto.CryptoExecutor;
-import org.briarproject.bramble.api.lifecycle.LifecycleManager;
-
-import java.util.concurrent.BlockingQueue;
-import java.util.concurrent.Executor;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.LinkedBlockingQueue;
-import java.util.concurrent.RejectedExecutionHandler;
-import java.util.concurrent.ThreadPoolExecutor;
-
-import javax.inject.Inject;
-import javax.inject.Singleton;
-
-import dagger.Module;
-import dagger.Provides;
-
-import static java.util.concurrent.TimeUnit.SECONDS;
-
-@Module
-public class CryptoExecutorModule {
-
-	public static class EagerSingletons {
-		@Inject
-		@CryptoExecutor
-		ExecutorService cryptoExecutor;
-	}
-
-	/**
-	 * The maximum number of executor threads.
-	 * <p>
-	 * The number of available processors can change during the lifetime of the
-	 * JVM, so this is just a reasonable guess.
-	 */
-	private static final int MAX_EXECUTOR_THREADS =
-			Math.max(1, Runtime.getRuntime().availableProcessors() - 1);
-
-	private final ExecutorService cryptoExecutor;
-
-	public CryptoExecutorModule() {
-		// Use an unbounded queue
-		BlockingQueue<Runnable> queue = new LinkedBlockingQueue<>();
-		// Discard tasks that are submitted during shutdown
-		RejectedExecutionHandler policy =
-				new ThreadPoolExecutor.DiscardPolicy();
-		// Create a limited # of threads and keep them in the pool for 60 secs
-		cryptoExecutor = new TimeLoggingExecutor("CryptoExecutor", 0,
-				MAX_EXECUTOR_THREADS, 60, SECONDS, queue, policy);
-	}
-
-	@Provides
-	@Singleton
-	@CryptoExecutor
-	ExecutorService provideCryptoExecutorService(
-			LifecycleManager lifecycleManager) {
-		lifecycleManager.registerForShutdown(cryptoExecutor);
-		return cryptoExecutor;
-	}
-
-	@Provides
-	@CryptoExecutor
-	Executor provideCryptoExecutor() {
-		return cryptoExecutor;
-	}
-}

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

@@ -1,24 +1,64 @@
 package org.briarproject.bramble.crypto;
 
+import org.briarproject.bramble.TimeLoggingExecutor;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.CryptoExecutor;
 import org.briarproject.bramble.api.crypto.KeyAgreementCrypto;
 import org.briarproject.bramble.api.crypto.PasswordStrengthEstimator;
 import org.briarproject.bramble.api.crypto.StreamDecrypterFactory;
 import org.briarproject.bramble.api.crypto.StreamEncrypterFactory;
 import org.briarproject.bramble.api.crypto.TransportCrypto;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.system.SecureRandomProvider;
 
 import java.security.SecureRandom;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.RejectedExecutionHandler;
+import java.util.concurrent.ThreadPoolExecutor;
 
+import javax.inject.Inject;
 import javax.inject.Provider;
 import javax.inject.Singleton;
 
 import dagger.Module;
 import dagger.Provides;
 
+import static java.util.concurrent.TimeUnit.SECONDS;
+
 @Module
 public class CryptoModule {
 
+	public static class EagerSingletons {
+		@Inject
+		@CryptoExecutor
+		ExecutorService cryptoExecutor;
+	}
+
+	/**
+	 * The maximum number of executor threads.
+	 * <p>
+	 * The number of available processors can change during the lifetime of the
+	 * JVM, so this is just a reasonable guess.
+	 */
+	private static final int MAX_EXECUTOR_THREADS =
+			Math.max(1, Runtime.getRuntime().availableProcessors() - 1);
+
+	private final ExecutorService cryptoExecutor;
+
+	public CryptoModule() {
+		// Use an unbounded queue
+		BlockingQueue<Runnable> queue = new LinkedBlockingQueue<>();
+		// Discard tasks that are submitted during shutdown
+		RejectedExecutionHandler policy =
+				new ThreadPoolExecutor.DiscardPolicy();
+		// Create a limited # of threads and keep them in the pool for 60 secs
+		cryptoExecutor = new TimeLoggingExecutor("CryptoExecutor", 0,
+				MAX_EXECUTOR_THREADS, 60, SECONDS, queue, policy);
+	}
+
 	@Provides
 	AuthenticatedCipher provideAuthenticatedCipher() {
 		return new XSalsa20Poly1305AuthenticatedCipher();
@@ -63,6 +103,21 @@ public class CryptoModule {
 		return keyAgreementCrypto;
 	}
 
+	@Provides
+	@Singleton
+	@CryptoExecutor
+	ExecutorService getCryptoExecutorService(
+			LifecycleManager lifecycleManager) {
+		lifecycleManager.registerForShutdown(cryptoExecutor);
+		return cryptoExecutor;
+	}
+
+	@Provides
+	@CryptoExecutor
+	Executor getCryptoExecutor() {
+		return cryptoExecutor;
+	}
+
 	@Provides
 	SecureRandom getSecureRandom(CryptoComponent crypto) {
 		return crypto.getSecureRandom();

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

@@ -152,47 +152,59 @@ public class MessageEncrypter {
 		}
 	}
 
-	public static void main(String[] args) {
+	public static void main(String[] args) throws Exception {
 		if (args.length < 1) {
 			printUsage();
-			System.exit(1);
+			return;
 		}
+		SecureRandom random = new SecureRandom();
+		MessageEncrypter encrypter = new MessageEncrypter(random);
 		if (args[0].equals("generate")) {
 			if (args.length != 3) {
 				printUsage();
-				System.exit(1);
+				return;
-			}
-			try {
-				generateKeyPair(args[1], args[2]);
-			} catch (Exception e) {
-				e.printStackTrace();
-				System.exit(2);
 			}
+			// Generate a key pair
+			KeyPair keyPair = encrypter.generateKeyPair();
+			PrintStream out = new PrintStream(new FileOutputStream(args[1]));
+			out.print(
+					StringUtils.toHexString(keyPair.getPublic().getEncoded()));
+			out.flush();
+			out.close();
+			out = new PrintStream(new FileOutputStream(args[2]));
+			out.print(
+					StringUtils.toHexString(keyPair.getPrivate().getEncoded()));
+			out.flush();
+			out.close();
 		} else if (args[0].equals("encrypt")) {
 			if (args.length != 2) {
 				printUsage();
-				System.exit(1);
+				return;
-			}
-			try {
-				encryptMessage(args[1]);
-			} catch (Exception e) {
-				e.printStackTrace();
-				System.exit(2);
 			}
+			// Encrypt a decrypted message
+			InputStream in = new FileInputStream(args[1]);
+			byte[] keyBytes = StringUtils.fromHexString(readFully(in).trim());
+			PublicKey publicKey =
+					encrypter.getKeyParser().parsePublicKey(keyBytes);
+			String message = readFully(System.in);
+			byte[] plaintext = message.getBytes(Charset.forName("UTF-8"));
+			byte[] ciphertext = encrypter.encrypt(publicKey, plaintext);
+			System.out.println(AsciiArmour.wrap(ciphertext, LINE_LENGTH));
 		} else if (args[0].equals("decrypt")) {
 			if (args.length != 2) {
 				printUsage();
-				System.exit(1);
+				return;
-			}
-			try {
-				decryptMessage(args[1]);
-			} catch (Exception e) {
-				e.printStackTrace();
-				System.exit(2);
 			}
+			// Decrypt an encrypted message
+			InputStream in = new FileInputStream(args[1]);
+			byte[] keyBytes = StringUtils.fromHexString(readFully(in).trim());
+			PrivateKey privateKey =
+					encrypter.getKeyParser().parsePrivateKey(keyBytes);
+			byte[] ciphertext = AsciiArmour.unwrap(readFully(System.in));
+			byte[] plaintext = encrypter.decrypt(privateKey, ciphertext);
+			System.out.println(new String(plaintext, Charset.forName("UTF-8")));
 		} else {
 			printUsage();
-			System.exit(1);
 		}
 	}
 
@@ -204,46 +216,6 @@ public class MessageEncrypter {
 		System.err.println("MessageEncrypter decrypt <private_key_file>");
 	}
 
-	private static void generateKeyPair(String publicKeyFile,
-			String privateKeyFile) throws Exception {
-		SecureRandom random = new SecureRandom();
-		MessageEncrypter encrypter = new MessageEncrypter(random);
-		KeyPair keyPair = encrypter.generateKeyPair();
-		PrintStream out = new PrintStream(new FileOutputStream(publicKeyFile));
-		out.print(StringUtils.toHexString(keyPair.getPublic().getEncoded()));
-		out.flush();
-		out.close();
-		out = new PrintStream(new FileOutputStream(privateKeyFile));
-		out.print(StringUtils.toHexString(keyPair.getPrivate().getEncoded()));
-		out.flush();
-		out.close();
-	}
-
-	private static void encryptMessage(String publicKeyFile) throws Exception {
-		SecureRandom random = new SecureRandom();
-		MessageEncrypter encrypter = new MessageEncrypter(random);
-		InputStream in = new FileInputStream(publicKeyFile);
-		byte[] keyBytes = StringUtils.fromHexString(readFully(in).trim());
-		PublicKey publicKey =
-				encrypter.getKeyParser().parsePublicKey(keyBytes);
-		String message = readFully(System.in);
-		byte[] plaintext = message.getBytes(Charset.forName("UTF-8"));
-		byte[] ciphertext = encrypter.encrypt(publicKey, plaintext);
-		System.out.println(AsciiArmour.wrap(ciphertext, LINE_LENGTH));
-	}
-
-	private static void decryptMessage(String privateKeyFile) throws Exception {
-		SecureRandom random = new SecureRandom();
-		MessageEncrypter encrypter = new MessageEncrypter(random);
-		InputStream in = new FileInputStream(privateKeyFile);
-		byte[] keyBytes = StringUtils.fromHexString(readFully(in).trim());
-		PrivateKey privateKey =
-				encrypter.getKeyParser().parsePrivateKey(keyBytes);
-		byte[] ciphertext = AsciiArmour.unwrap(readFully(System.in));
-		byte[] plaintext = encrypter.decrypt(privateKey, ciphertext);
-		System.out.println(new String(plaintext, Charset.forName("UTF-8")));
-	}
-
 	private static String readFully(InputStream in) throws IOException {
 		String newline = System.getProperty("line.separator");
 		StringBuilder stringBuilder = new StringBuilder();

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

@@ -10,37 +10,37 @@ import java.security.GeneralSecurityException;
 interface Signature {
 
 	/**
-	 * @see java.security.Signature#initSign(java.security.PrivateKey)
+	 * @see {@link java.security.Signature#initSign(java.security.PrivateKey)}
 	 */
 	void initSign(PrivateKey k) throws GeneralSecurityException;
 
 	/**
-	 * @see java.security.Signature#initVerify(java.security.PublicKey)
+	 * @see {@link java.security.Signature#initVerify(java.security.PublicKey)}
 	 */
 	void initVerify(PublicKey k) throws GeneralSecurityException;
 
 	/**
-	 * @see java.security.Signature#update(byte)
+	 * @see {@link java.security.Signature#update(byte)}
 	 */
 	void update(byte b) throws GeneralSecurityException;
 
 	/**
-	 * @see java.security.Signature#update(byte[])
+	 * @see {@link java.security.Signature#update(byte[])}
 	 */
 	void update(byte[] b) throws GeneralSecurityException;
 
 	/**
-	 * @see java.security.Signature#update(byte[], int, int)
+	 * @see {@link java.security.Signature#update(byte[], int, int)}
 	 */
 	void update(byte[] b, int off, int len) throws GeneralSecurityException;
 
 	/**
-	 * @see java.security.Signature#sign()}
+	 * @see {@link java.security.Signature#sign()}
 	 */
 	byte[] sign() throws GeneralSecurityException;
 
 	/**
-	 * @see java.security.Signature#verify(byte[])
+	 * @see {@link java.security.Signature#verify(byte[])}
 	 */
 	boolean verify(byte[] signature) throws GeneralSecurityException;
 }

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

@@ -36,8 +36,7 @@ class TransportCryptoImpl implements TransportCrypto {
 
 	@Override
 	public TransportKeys deriveTransportKeys(TransportId t,
-			SecretKey master, long rotationPeriod, boolean alice,
+			SecretKey master, long rotationPeriod, boolean alice) {
-			boolean active) {
 		// Keys for the previous period are derived from the master secret
 		SecretKey inTagPrev = deriveTagKey(master, t, !alice);
 		SecretKey inHeaderPrev = deriveHeaderKey(master, t, !alice);
@@ -58,7 +57,7 @@ class TransportCryptoImpl implements TransportCrypto {
 		IncomingKeys inNext = new IncomingKeys(inTagNext, inHeaderNext,
 				rotationPeriod + 1);
 		OutgoingKeys outCurr = new OutgoingKeys(outTagCurr, outHeaderCurr,
-				rotationPeriod, active);
+				rotationPeriod);
 		// Collect and return the keys
 		return new TransportKeys(t, inPrev, inCurr, inNext, outCurr);
 	}
@@ -72,7 +71,6 @@ class TransportCryptoImpl implements TransportCrypto {
 		IncomingKeys inNext = k.getNextIncomingKeys();
 		OutgoingKeys outCurr = k.getCurrentOutgoingKeys();
 		long startPeriod = outCurr.getRotationPeriod();
-		boolean active = outCurr.isActive();
 		// Rotate the keys
 		for (long p = startPeriod + 1; p <= rotationPeriod; p++) {
 			inPrev = inCurr;
@@ -82,7 +80,7 @@ class TransportCryptoImpl implements TransportCrypto {
 			inNext = new IncomingKeys(inNextTag, inNextHeader, p + 1);
 			SecretKey outCurrTag = rotateKey(outCurr.getTagKey(), p);
 			SecretKey outCurrHeader = rotateKey(outCurr.getHeaderKey(), p);
-			outCurr = new OutgoingKeys(outCurrTag, outCurrHeader, p, active);
+			outCurr = new OutgoingKeys(outCurrTag, outCurrHeader, p);
 		}
 		// Collect and return the keys
 		return new TransportKeys(k.getTransportId(), inPrev, inCurr, inNext,

bramble-core/src/main/java/org/briarproject/bramble/data/BdfReaderFactoryImpl.java

@@ -8,7 +8,6 @@ import java.io.InputStream;
 
 import javax.annotation.concurrent.Immutable;
 
-import static org.briarproject.bramble.api.data.BdfReader.DEFAULT_MAX_BUFFER_SIZE;
 import static org.briarproject.bramble.api.data.BdfReader.DEFAULT_NESTED_LIMIT;
 
 @Immutable
@@ -17,13 +16,11 @@ class BdfReaderFactoryImpl implements BdfReaderFactory {
 
 	@Override
 	public BdfReader createReader(InputStream in) {
-		return new BdfReaderImpl(in, DEFAULT_NESTED_LIMIT,
+		return new BdfReaderImpl(in, DEFAULT_NESTED_LIMIT);
-				DEFAULT_MAX_BUFFER_SIZE);
 	}
 
 	@Override
-	public BdfReader createReader(InputStream in, int nestedLimit,
+	public BdfReader createReader(InputStream in, int nestedLimit) {
-			int maxBufferSize) {
+		return new BdfReaderImpl(in, nestedLimit);
-		return new BdfReaderImpl(in, nestedLimit, maxBufferSize);
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/data/BdfReaderImpl.java

@@ -37,16 +37,15 @@ class BdfReaderImpl implements BdfReader {
 	private static final byte[] EMPTY_BUFFER = new byte[0];
 
 	private final InputStream in;
-	private final int nestedLimit, maxBufferSize;
+	private final int nestedLimit;
 
 	private boolean hasLookahead = false, eof = false;
 	private byte next;
 	private byte[] buf = new byte[8];
 
-	BdfReaderImpl(InputStream in, int nestedLimit, int maxBufferSize) {
+	BdfReaderImpl(InputStream in, int nestedLimit) {
 		this.in = in;
 		this.nestedLimit = nestedLimit;
-		this.maxBufferSize = maxBufferSize;
 	}
 
 	private void readLookahead() throws IOException {
@@ -92,8 +91,8 @@ class BdfReaderImpl implements BdfReader {
 		if (hasBoolean()) return readBoolean();
 		if (hasLong()) return readLong();
 		if (hasDouble()) return readDouble();
-		if (hasString()) return readString();
+		if (hasString()) return readString(Integer.MAX_VALUE);
-		if (hasRaw()) return readRaw();
+		if (hasRaw()) return readRaw(Integer.MAX_VALUE);
 		if (hasList()) return readList(level);
 		if (hasDictionary()) return readDictionary(level);
 		throw new FormatException();
@@ -246,11 +245,11 @@ class BdfReaderImpl implements BdfReader {
 	}
 
 	@Override
-	public String readString() throws IOException {
+	public String readString(int maxLength) throws IOException {
 		if (!hasString()) throw new FormatException();
 		hasLookahead = false;
 		int length = readStringLength();
-		if (length < 0 || length > maxBufferSize) throw new FormatException();
+		if (length < 0 || length > maxLength) throw new FormatException();
 		if (length == 0) return "";
 		readIntoBuffer(length);
 		return new String(buf, 0, length, "UTF-8");
@@ -280,11 +279,11 @@ class BdfReaderImpl implements BdfReader {
 	}
 
 	@Override
-	public byte[] readRaw() throws IOException {
+	public byte[] readRaw(int maxLength) throws IOException {
 		if (!hasRaw()) throw new FormatException();
 		hasLookahead = false;
 		int length = readRawLength();
-		if (length < 0 || length > maxBufferSize) throw new FormatException();
+		if (length < 0 || length > maxLength) throw new FormatException();
 		if (length == 0) return EMPTY_BUFFER;
 		byte[] b = new byte[length];
 		readIntoBuffer(b, length);
@@ -382,7 +381,7 @@ class BdfReaderImpl implements BdfReader {
 		BdfDictionary dictionary = new BdfDictionary();
 		readDictionaryStart();
 		while (!hasDictionaryEnd())
-			dictionary.put(readString(), readObject(level + 1));
+			dictionary.put(readString(Integer.MAX_VALUE), readObject(level + 1));
 		readDictionaryEnd();
 		return dictionary;
 	}

bramble-core/src/main/java/org/briarproject/bramble/data/MetadataParserImpl.java

@@ -59,8 +59,8 @@ class MetadataParserImpl implements MetadataParser {
 		if (reader.hasBoolean()) return reader.readBoolean();
 		if (reader.hasLong()) return reader.readLong();
 		if (reader.hasDouble()) return reader.readDouble();
-		if (reader.hasString()) return reader.readString();
+		if (reader.hasString()) return reader.readString(Integer.MAX_VALUE);
-		if (reader.hasRaw()) return reader.readRaw();
+		if (reader.hasRaw()) return reader.readRaw(Integer.MAX_VALUE);
 		if (reader.hasList()) return reader.readList();
 		if (reader.hasDictionary()) return reader.readDictionary();
 		throw new FormatException();

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

@@ -21,8 +21,6 @@ import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.MessageStatus;
 import org.briarproject.bramble.api.sync.ValidationManager.State;
-import org.briarproject.bramble.api.transport.KeySet;
-import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.util.Collection;
@@ -34,8 +32,8 @@ import javax.annotation.Nullable;
  * A low-level interface to the database (DatabaseComponent provides a
  * high-level interface). Most operations take a transaction argument, which is
  * obtained by calling {@link #startTransaction()}. Every transaction must be
- * terminated by calling either {@link #abortTransaction(Object) abortTransaction(T)} or
+ * terminated by calling either {@link #abortTransaction(T)} or
- * {@link #commitTransaction(Object) commitTransaction(T)}, even if an exception is thrown.
+ * {@link #commitTransaction(T)}, even if an exception is thrown.
  */
 @NotNullByDefault
 interface Database<T> {
@@ -107,11 +105,10 @@ interface Database<T> {
 			@Nullable ContactId sender) throws DbException;
 
 	/**
-	 * Adds a dependency between two messages, where the dependent message is
+	 * Adds a dependency between two messages in the given group.
-	 * in the given state.
 	 */
-	void addMessageDependency(T txn, Message dependent, MessageId dependency,
+	void addMessageDependency(T txn, GroupId g, MessageId dependent,
-			State dependentState) throws DbException;
+			MessageId dependency) throws DbException;
 
 	/**
 	 * Records that a message has been offered by the given contact.
@@ -125,10 +122,9 @@ interface Database<T> {
 			throws DbException;
 
 	/**
-	 * Stores the given transport keys for the given contact and returns a
+	 * Stores transport keys for a newly added contact.
-	 * key set ID.
 	 */
-	KeySetId addTransportKeys(T txn, ContactId c, TransportKeys k)
+	void addTransportKeys(T txn, ContactId c, TransportKeys k)
 			throws DbException;
 
 	/**
@@ -260,8 +256,7 @@ interface Database<T> {
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<Group> getGroups(T txn, ClientId c, int majorVersion)
+	Collection<Group> getGroups(T txn, ClientId c) throws DbException;
-			throws DbException;
 
 	/**
 	 * Returns the given group's visibility to the given contact, or
@@ -297,8 +292,10 @@ interface Database<T> {
 
 	/**
 	 * Returns the IDs and states of all dependencies of the given message.
-	 * For missing dependencies and dependencies in other groups, the state
+	 * Missing dependencies have the state {@link State UNKNOWN}.
-	 * {@link State UNKNOWN} is returned.
+	 * Dependencies in other groups have the state {@link State INVALID}.
+	 * Note that these states are not set on the dependencies themselves; the
+	 * returned states should only be taken in the context of the given message.
 	 * <p/>
 	 * Read-only.
 	 */
@@ -306,9 +303,9 @@ interface Database<T> {
 			throws DbException;
 
 	/**
-	 * Returns the IDs and states of all dependents of the given message.
+	 * Returns all IDs and states of all dependents of the given message.
-	 * Dependents in other groups are not returned. If the given message is
+	 * Messages in other groups that declare a dependency on the given message
-	 * missing, no dependents are returned.
+	 * will be returned even though such dependencies are invalid.
 	 * <p/>
 	 * Read-only.
 	 */
@@ -316,16 +313,16 @@ interface Database<T> {
 			throws DbException;
 
 	/**
-	 * Returns the IDs of all delivered messages in the given group.
+	 * Returns the IDs of all messages in the given group.
 	 * <p/>
 	 * Read-only.
 	 */
 	Collection<MessageId> getMessageIds(T txn, GroupId g) throws DbException;
 
 	/**
-	 * Returns the IDs of any delivered messages in the given group with
+	 * Returns the IDs of any messages in the given group with metadata
-	 * metadata that matches all entries in the given query. If the query is
+	 * matching all entries in the given query. If the query is empty, the IDs
-	 * empty, the IDs of all delivered messages are returned.
+	 * of all messages are returned.
 	 * <p/>
 	 * Read-only.
 	 */
@@ -341,9 +338,9 @@ interface Database<T> {
 			throws DbException;
 
 	/**
-	 * Returns the metadata for any delivered messages in the given group with
+	 * Returns the metadata for any messages in the given group with metadata
-	 * metadata that matches all entries in the given query. If the query is
+	 * matching all entries in the given query. If the query is empty, the
-	 * empty, the metadata for all delivered messages is returned.
+	 * metadata for all messages is returned.
 	 * <p/>
 	 * Read-only.
 	 */
@@ -351,8 +348,7 @@ interface Database<T> {
 			Metadata query) throws DbException;
 
 	/**
-	 * Returns the metadata for the given delivered or pending message.
+	 * Returns the metadata for the given delivered message.
-	 * This is only meant to be used by the ValidationManager.
 	 * <p/>
 	 * Read-only.
 	 */
@@ -360,7 +356,7 @@ interface Database<T> {
 			throws DbException;
 
 	/**
-	 * Returns the metadata for the given delivered message.
+	 * Returns the metadata for the given message.
 	 * <p/>
 	 * Read-only.
 	 */
@@ -374,8 +370,8 @@ interface Database<T> {
 	State getMessageState(T txn, MessageId m) throws DbException;
 
 	/**
-	 * Returns the status of all delivered messages in the given group with
+	 * Returns the status of all messages in the given group with respect
-	 * respect to the given contact.
+	 * to the given contact.
 	 * <p/>
 	 * Read-only.
 	 */
@@ -383,13 +379,11 @@ interface Database<T> {
 			throws DbException;
 
 	/**
-	 * Returns the status of the given delivered message with respect to the
+	 * Returns the status of the given message with respect to the given
-	 * given contact, or null if the message's group is invisible to the
 	 * contact.
 	 * <p/>
 	 * Read-only.
 	 */
-	@Nullable
 	MessageStatus getMessageStatus(T txn, ContactId c, MessageId m)
 			throws DbException;
 
@@ -493,14 +487,15 @@ interface Database<T> {
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<KeySet> getTransportKeys(T txn, TransportId t)
+	Map<ContactId, TransportKeys> getTransportKeys(T txn, TransportId t)
 			throws DbException;
 
 	/**
-	 * Increments the outgoing stream counter for the given transport keys.
+	 * Increments the outgoing stream counter for the given contact and
+	 * transport in the given rotation period.
 	 */
-	void incrementStreamCounter(T txn, TransportId t, KeySetId k)
+	void incrementStreamCounter(T txn, ContactId c, TransportId t,
-			throws DbException;
+			long rotationPeriod) throws DbException;
 
 	/**
 	 * Marks the given messages as not needing to be acknowledged to the
@@ -590,12 +585,6 @@ interface Database<T> {
 	 */
 	void removeTransport(T txn, TransportId t) throws DbException;
 
-	/**
-	 * Removes the given transport keys from the database.
-	 */
-	void removeTransportKeys(T txn, TransportId t, KeySetId k)
-			throws DbException;
-
 	/**
 	 * Resets the transmission count and expiry time of the given message with
 	 * respect to the given contact.
@@ -631,18 +620,12 @@ interface Database<T> {
 	void setMessageState(T txn, MessageId m, State state) throws DbException;
 
 	/**
-	 * Sets the reordering window for the given key set and transport in the
+	 * Sets the reordering window for the given contact and transport in the
 	 * given rotation period.
 	 */
-	void setReorderingWindow(T txn, KeySetId k, TransportId t,
+	void setReorderingWindow(T txn, ContactId c, TransportId t,
 			long rotationPeriod, long base, byte[] bitmap) throws DbException;
 
-	/**
-	 * Marks the given transport keys as usable for outgoing streams.
-	 */
-	void setTransportKeysActive(T txn, TransportId t, KeySetId k)
-		throws DbException;
-
 	/**
 	 * Updates the transmission count and expiry time of the given message
 	 * with respect to the given contact, using the latency of the transport
@@ -652,7 +635,8 @@ interface Database<T> {
 			throws DbException;
 
 	/**
-	 * Updates the given transport keys following key rotation.
+	 * Stores the given transport keys, deleting any keys they have replaced.
 	 */
-	void updateTransportKeys(T txn, KeySet ks) throws DbException;
+	void updateTransportKeys(T txn, Map<ContactId, TransportKeys> keys)
+			throws DbException;
 }

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

@@ -51,15 +51,15 @@ import org.briarproject.bramble.api.sync.event.MessageToAckEvent;
 import org.briarproject.bramble.api.sync.event.MessageToRequestEvent;
 import org.briarproject.bramble.api.sync.event.MessagesAckedEvent;
 import org.briarproject.bramble.api.sync.event.MessagesSentEvent;
-import org.briarproject.bramble.api.transport.KeySet;
-import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Map.Entry;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 import java.util.logging.Logger;
@@ -234,7 +234,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public KeySetId addTransportKeys(Transaction transaction, ContactId c,
+	public void addTransportKeys(Transaction transaction, ContactId c,
 			TransportKeys k) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
@@ -242,7 +242,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			throw new NoSuchContactException();
 		if (!db.containsTransport(txn, k.getTransportId()))
 			throw new NoSuchTransportException();
-		return db.addTransportKeys(txn, c, k);
+		db.addTransportKeys(txn, c, k);
 	}
 
 	@Override
@@ -423,10 +423,10 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public Collection<Group> getGroups(Transaction transaction, ClientId c,
+	public Collection<Group> getGroups(Transaction transaction, ClientId c)
-			int majorVersion) throws DbException {
+			throws DbException {
 		T txn = unbox(transaction);
-		return db.getGroups(txn, c, majorVersion);
+		return db.getGroups(txn, c);
 	}
 
 	@Override
@@ -454,15 +454,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.getLocalAuthors(txn);
 	}
 
-	@Override
-	public Collection<MessageId> getMessageIds(Transaction transaction,
-			GroupId g) throws DbException {
-		T txn = unbox(transaction);
-		if (!db.containsGroup(txn, g))
-			throw new NoSuchGroupException();
-		return db.getMessageIds(txn, g);
-	}
-
 	@Override
 	public Collection<MessageId> getMessagesToValidate(Transaction transaction)
 			throws DbException {
@@ -548,13 +539,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			throw new NoSuchContactException();
 		if (!db.containsGroup(txn, g))
 			throw new NoSuchGroupException();
-		if (db.getGroupVisibility(txn, c, g) == INVISIBLE) {
-			// No status rows exist - return default statuses
-			Collection<MessageStatus> statuses = new ArrayList<>();
-			for (MessageId m : db.getMessageIds(txn, g))
-				statuses.add(new MessageStatus(m, c, false, false));
-			return statuses;
-		}
 		return db.getMessageStatus(txn, c, g);
 	}
 
@@ -566,9 +550,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			throw new NoSuchContactException();
 		if (!db.containsMessage(txn, m))
 			throw new NoSuchMessageException();
-		MessageStatus status = db.getMessageStatus(txn, c, m);
+		return db.getMessageStatus(txn, c, m);
-		if (status == null) return new MessageStatus(m, c, false, false);
-		return status;
 	}
 
 	@Override
@@ -604,8 +586,8 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public Collection<KeySet> getTransportKeys(Transaction transaction,
+	public Map<ContactId, TransportKeys> getTransportKeys(
-			TransportId t) throws DbException {
+			Transaction transaction, TransportId t) throws DbException {
 		T txn = unbox(transaction);
 		if (!db.containsTransport(txn, t))
 			throw new NoSuchTransportException();
@@ -613,13 +595,15 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public void incrementStreamCounter(Transaction transaction, TransportId t,
+	public void incrementStreamCounter(Transaction transaction, ContactId c,
-			KeySetId k) throws DbException {
+			TransportId t, long rotationPeriod) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
+		if (!db.containsContact(txn, c))
+			throw new NoSuchContactException();
 		if (!db.containsTransport(txn, t))
 			throw new NoSuchTransportException();
-		db.incrementStreamCounter(txn, t, k);
+		db.incrementStreamCounter(txn, c, t, rotationPeriod);
 	}
 
 	@Override
@@ -781,7 +765,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		T txn = unbox(transaction);
 		if (!db.containsMessage(txn, m))
 			throw new NoSuchMessageException();
-		// TODO: Don't allow messages with dependents to be removed
 		db.removeMessage(txn, m);
 	}
 
@@ -795,16 +778,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		db.removeTransport(txn, t);
 	}
 
-	@Override
-	public void removeTransportKeys(Transaction transaction,
-			TransportId t, KeySetId k) throws DbException {
-		if (transaction.isReadOnly()) throw new IllegalArgumentException();
-		T txn = unbox(transaction);
-		if (!db.containsTransport(txn, t))
-			throw new NoSuchTransportException();
-		db.removeTransportKeys(txn, t, k);
-	}
-
 	@Override
 	public void setContactVerified(Transaction transaction, ContactId c)
 			throws DbException {
@@ -877,41 +850,39 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		T txn = unbox(transaction);
 		if (!db.containsMessage(txn, dependent.getId()))
 			throw new NoSuchMessageException();
-		State dependentState = db.getMessageState(txn, dependent.getId());
 		for (MessageId dependency : dependencies) {
-			db.addMessageDependency(txn, dependent, dependency, dependentState);
+			db.addMessageDependency(txn, dependent.getGroupId(),
+					dependent.getId(), dependency);
 		}
 	}
 
 	@Override
-	public void setReorderingWindow(Transaction transaction, KeySetId k,
+	public void setReorderingWindow(Transaction transaction, ContactId c,
 			TransportId t, long rotationPeriod, long base, byte[] bitmap)
 			throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
+		if (!db.containsContact(txn, c))
+			throw new NoSuchContactException();
 		if (!db.containsTransport(txn, t))
 			throw new NoSuchTransportException();
-		db.setReorderingWindow(txn, k, t, rotationPeriod, base, bitmap);
+		db.setReorderingWindow(txn, c, t, rotationPeriod, base, bitmap);
-	}
-
-	@Override
-	public void setTransportKeysActive(Transaction transaction, TransportId t,
-			KeySetId k) throws DbException {
-		if (transaction.isReadOnly()) throw new IllegalArgumentException();
-		T txn = unbox(transaction);
-		if (!db.containsTransport(txn, t))
-			throw new NoSuchTransportException();
-		db.setTransportKeysActive(txn, t, k);
 	}
 
 	@Override
 	public void updateTransportKeys(Transaction transaction,
-			Collection<KeySet> keys) throws DbException {
+			Map<ContactId, TransportKeys> keys) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
-		for (KeySet ks : keys) {
+		Map<ContactId, TransportKeys> filtered = new HashMap<>();
-			TransportId t = ks.getTransportKeys().getTransportId();
+		for (Entry<ContactId, TransportKeys> e : keys.entrySet()) {
-			if (db.containsTransport(txn, t)) db.updateTransportKeys(txn, ks);
+			ContactId c = e.getKey();
+			TransportKeys k = e.getValue();
+			if (db.containsContact(txn, c)
+					&& db.containsTransport(txn, k.getTransportId())) {
+				filtered.put(c, k);
+			}
 		}
+		db.updateTransportKeys(txn, filtered);
 	}
 }

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

@@ -25,8 +25,6 @@ import org.briarproject.bramble.api.sync.MessageStatus;
 import org.briarproject.bramble.api.sync.ValidationManager.State;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.transport.IncomingKeys;
-import org.briarproject.bramble.api.transport.KeySet;
-import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.OutgoingKeys;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
@@ -52,8 +50,6 @@ import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 
-import static java.sql.Types.INTEGER;
-import static java.util.Collections.singletonList;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.api.db.Metadata.REMOVE;
@@ -61,6 +57,7 @@ import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
 import static org.briarproject.bramble.api.sync.Group.Visibility.VISIBLE;
 import static org.briarproject.bramble.api.sync.ValidationManager.State.DELIVERED;
+import static org.briarproject.bramble.api.sync.ValidationManager.State.INVALID;
 import static org.briarproject.bramble.api.sync.ValidationManager.State.PENDING;
 import static org.briarproject.bramble.api.sync.ValidationManager.State.UNKNOWN;
 import static org.briarproject.bramble.db.DatabaseConstants.DB_SETTINGS_NAMESPACE;
@@ -75,12 +72,7 @@ import static org.briarproject.bramble.db.ExponentialBackoff.calculateExpiry;
 abstract class JdbcDatabase implements Database<Connection> {
 
 	// Package access for testing
-	static final int CODE_SCHEMA_VERSION = 39;
+	static final int CODE_SCHEMA_VERSION = 35;
-
-	// Rotation period offsets for incoming transport keys
-	private static final int OFFSET_PREV = -1;
-	private static final int OFFSET_CURR = 0;
-	private static final int OFFSET_NEXT = 1;
 
 	private static final String CREATE_SETTINGS =
 			"CREATE TABLE settings"
@@ -118,7 +110,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 			"CREATE TABLE groups"
 					+ " (groupId _HASH NOT NULL,"
 					+ " clientId _STRING NOT NULL,"
-					+ " majorVersion INT NOT NULL,"
 					+ " descriptor _BINARY NOT NULL,"
 					+ " PRIMARY KEY (groupId))";
 
@@ -179,10 +170,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " (groupId _HASH NOT NULL,"
 					+ " messageId _HASH NOT NULL,"
 					+ " dependencyId _HASH NOT NULL," // Not a foreign key
-					+ " messageState INT NOT NULL," // Denormalised
-					// Denormalised, null if dependency is missing or in a
-					// different group
-					+ " dependencyState INT,"
 					+ " FOREIGN KEY (groupId)"
 					+ " REFERENCES groups (groupId)"
 					+ " ON DELETE CASCADE,"
@@ -232,63 +219,51 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " maxLatency INT NOT NULL,"
 					+ " PRIMARY KEY (transportId))";
 
-	private static final String CREATE_OUTGOING_KEYS =
-			"CREATE TABLE outgoingKeys"
-					+ " (transportId _STRING NOT NULL,"
-					+ " keySetId _COUNTER,"
-					+ " rotationPeriod BIGINT NOT NULL,"
-					+ " contactId INT NOT NULL,"
-					+ " tagKey _SECRET NOT NULL,"
-					+ " headerKey _SECRET NOT NULL,"
-					+ " stream BIGINT NOT NULL,"
-					+ " active BOOLEAN NOT NULL,"
-					+ " PRIMARY KEY (transportId, keySetId),"
-					+ " FOREIGN KEY (transportId)"
-					+ " REFERENCES transports (transportId)"
-					+ " ON DELETE CASCADE,"
-					+ " UNIQUE (keySetId),"
-					+ " FOREIGN KEY (contactId)"
-					+ " REFERENCES contacts (contactId)"
-					+ " ON DELETE CASCADE)";
-
 	private static final String CREATE_INCOMING_KEYS =
 			"CREATE TABLE incomingKeys"
-					+ " (transportId _STRING NOT NULL,"
+					+ " (contactId INT NOT NULL,"
-					+ " keySetId INT NOT NULL,"
+					+ " transportId _STRING NOT NULL,"
 					+ " rotationPeriod BIGINT NOT NULL,"
-					+ " contactId INT NOT NULL,"
 					+ " tagKey _SECRET NOT NULL,"
 					+ " headerKey _SECRET NOT NULL,"
 					+ " base BIGINT NOT NULL,"
 					+ " bitmap _BINARY NOT NULL,"
-					+ " periodOffset INT NOT NULL,"
+					+ " PRIMARY KEY (contactId, transportId, rotationPeriod),"
-					+ " PRIMARY KEY (transportId, keySetId, periodOffset),"
-					+ " FOREIGN KEY (transportId)"
-					+ " REFERENCES transports (transportId)"
-					+ " ON DELETE CASCADE,"
-					+ " FOREIGN KEY (keySetId)"
-					+ " REFERENCES outgoingKeys (keySetId)"
-					+ " ON DELETE CASCADE,"
 					+ " FOREIGN KEY (contactId)"
 					+ " REFERENCES contacts (contactId)"
+					+ " ON DELETE CASCADE,"
+					+ " FOREIGN KEY (transportId)"
+					+ " REFERENCES transports (transportId)"
+					+ " ON DELETE CASCADE)";
+
+	private static final String CREATE_OUTGOING_KEYS =
+			"CREATE TABLE outgoingKeys"
+					+ " (contactId INT NOT NULL,"
+					+ " transportId _STRING NOT NULL,"
+					+ " rotationPeriod BIGINT NOT NULL,"
+					+ " tagKey _SECRET NOT NULL,"
+					+ " headerKey _SECRET NOT NULL,"
+					+ " stream BIGINT NOT NULL,"
+					+ " PRIMARY KEY (contactId, transportId),"
+					+ " FOREIGN KEY (contactId)"
+					+ " REFERENCES contacts (contactId)"
+					+ " ON DELETE CASCADE,"
+					+ " FOREIGN KEY (transportId)"
+					+ " REFERENCES transports (transportId)"
 					+ " ON DELETE CASCADE)";
 
 	private static final String INDEX_CONTACTS_BY_AUTHOR_ID =
 			"CREATE INDEX IF NOT EXISTS contactsByAuthorId"
 					+ " ON contacts (authorId)";
 
-	private static final String INDEX_GROUPS_BY_CLIENT_ID_MAJOR_VERSION =
+	private static final String INDEX_GROUPS_BY_CLIENT_ID =
-			"CREATE INDEX IF NOT EXISTS groupsByClientIdMajorVersion"
+			"CREATE INDEX IF NOT EXISTS groupsByClientId"
-					+ " ON groups (clientId, majorVersion)";
+					+ " ON groups (clientId)";
 
 	private static final String INDEX_MESSAGE_METADATA_BY_GROUP_ID_STATE =
 			"CREATE INDEX IF NOT EXISTS messageMetadataByGroupIdState"
 					+ " ON messageMetadata (groupId, state)";
 
-	private static final String INDEX_MESSAGE_DEPENDENCIES_BY_DEPENDENCY_ID =
-			"CREATE INDEX IF NOT EXISTS messageDependenciesByDependencyId"
-					+ " ON messageDependencies (dependencyId)";
-
 	private static final String INDEX_STATUSES_BY_CONTACT_ID_GROUP_ID =
 			"CREATE INDEX IF NOT EXISTS statusesByContactIdGroupId"
 					+ " ON statuses (contactId, groupId)";
@@ -390,7 +365,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 
 	// Package access for testing
 	List<Migration<Connection>> getMigrations() {
-		return singletonList(new Migration38_39());
+		return Collections.emptyList();
 	}
 
 	private void storeSchemaVersion(Connection txn, int version)
@@ -432,8 +407,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 			s.executeUpdate(insertTypeNames(CREATE_OFFERS));
 			s.executeUpdate(insertTypeNames(CREATE_STATUSES));
 			s.executeUpdate(insertTypeNames(CREATE_TRANSPORTS));
-			s.executeUpdate(insertTypeNames(CREATE_OUTGOING_KEYS));
 			s.executeUpdate(insertTypeNames(CREATE_INCOMING_KEYS));
+			s.executeUpdate(insertTypeNames(CREATE_OUTGOING_KEYS));
 			s.close();
 		} catch (SQLException e) {
 			tryToClose(s);
@@ -446,9 +421,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		try {
 			s = txn.createStatement();
 			s.executeUpdate(INDEX_CONTACTS_BY_AUTHOR_ID);
-			s.executeUpdate(INDEX_GROUPS_BY_CLIENT_ID_MAJOR_VERSION);
+			s.executeUpdate(INDEX_GROUPS_BY_CLIENT_ID);
 			s.executeUpdate(INDEX_MESSAGE_METADATA_BY_GROUP_ID_STATE);
-			s.executeUpdate(INDEX_MESSAGE_DEPENDENCIES_BY_DEPENDENCY_ID);
 			s.executeUpdate(INDEX_STATUSES_BY_CONTACT_ID_GROUP_ID);
 			s.executeUpdate(INDEX_STATUSES_BY_CONTACT_ID_TIMESTAMP);
 			s.close();
@@ -614,14 +588,12 @@ abstract class JdbcDatabase implements Database<Connection> {
 	public void addGroup(Connection txn, Group g) throws DbException {
 		PreparedStatement ps = null;
 		try {
-			String sql = "INSERT INTO groups"
+			String sql = "INSERT INTO groups (groupId, clientId, descriptor)"
-					+ " (groupId, clientId, majorVersion, descriptor)"
+					+ " VALUES (?, ?, ?)";
-					+ " VALUES (?, ?, ?, ?)";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, g.getId().getBytes());
 			ps.setString(2, g.getClientId().getString());
-			ps.setInt(3, g.getMajorVersion());
+			ps.setBytes(3, g.getDescriptor());
-			ps.setBytes(4, g.getDescriptor());
 			int affected = ps.executeUpdate();
 			if (affected != 1) throw new DbStateException();
 			ps.close();
@@ -743,17 +715,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 						m.getLength(), state, e.getValue(), messageShared,
 						false, seen);
 			}
-			// Update denormalised column in messageDependencies if dependency
-			// is in same group as dependent
-			sql = "UPDATE messageDependencies SET dependencyState = ?"
-					+ " WHERE groupId = ? AND dependencyId = ?";
-			ps = txn.prepareStatement(sql);
-			ps.setInt(1, state.getValue());
-			ps.setBytes(2, m.getGroupId().getBytes());
-			ps.setBytes(3, m.getId().getBytes());
-			affected = ps.executeUpdate();
-			if (affected < 0) throw new DbStateException();
-			ps.close();
 		} catch (SQLException e) {
 			tryToClose(ps);
 			throw new DbException(e);
@@ -823,42 +784,21 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public void addMessageDependency(Connection txn, Message dependent,
+	public void addMessageDependency(Connection txn, GroupId g,
-			MessageId dependency, State dependentState) throws DbException {
+			MessageId dependent, MessageId dependency) throws DbException {
 		PreparedStatement ps = null;
-		ResultSet rs = null;
 		try {
-			// Get state of dependency if present and in same group as dependent
+			String sql = "INSERT INTO messageDependencies"
-			String sql = "SELECT state FROM messages"
+					+ " (groupId, messageId, dependencyId)"
-					+ " WHERE messageId = ? AND groupId = ?";
+					+ " VALUES (?, ?, ?)";
 			ps = txn.prepareStatement(sql);
-			ps.setBytes(1, dependency.getBytes());
+			ps.setBytes(1, g.getBytes());
-			ps.setBytes(2, dependent.getGroupId().getBytes());
+			ps.setBytes(2, dependent.getBytes());
-			rs = ps.executeQuery();
-			State dependencyState = null;
-			if (rs.next()) {
-				dependencyState = State.fromValue(rs.getInt(1));
-				if (rs.next()) throw new DbStateException();
-			}
-			rs.close();
-			ps.close();
-			// Create messageDependencies row
-			sql = "INSERT INTO messageDependencies"
-					+ " (groupId, messageId, dependencyId, messageState,"
-					+ " dependencyState)"
-					+ " VALUES (?, ?, ?, ? ,?)";
-			ps = txn.prepareStatement(sql);
-			ps.setBytes(1, dependent.getGroupId().getBytes());
-			ps.setBytes(2, dependent.getId().getBytes());
 			ps.setBytes(3, dependency.getBytes());
-			ps.setInt(4, dependentState.getValue());
-			if (dependencyState == null) ps.setNull(5, INTEGER);
-			else ps.setInt(5, dependencyState.getValue());
 			int affected = ps.executeUpdate();
 			if (affected != 1) throw new DbStateException();
 			ps.close();
 		} catch (SQLException e) {
-			tryToClose(rs);
 			tryToClose(ps);
 			throw new DbException(e);
 		}
@@ -884,81 +824,62 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public KeySetId addTransportKeys(Connection txn, ContactId c,
+	public void addTransportKeys(Connection txn, ContactId c, TransportKeys k)
-			TransportKeys k) throws DbException {
+			throws DbException {
 		PreparedStatement ps = null;
-		ResultSet rs = null;
 		try {
-			// Store the outgoing keys
+			// Store the incoming keys
-			String sql = "INSERT INTO outgoingKeys (contactId, transportId,"
+			String sql = "INSERT INTO incomingKeys (contactId, transportId,"
-					+ " rotationPeriod, tagKey, headerKey, stream, active)"
+					+ " rotationPeriod, tagKey, headerKey, base, bitmap)"
 					+ " VALUES (?, ?, ?, ?, ?, ?, ?)";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, c.getInt());
 			ps.setString(2, k.getTransportId().getString());
+			// Previous rotation period
+			IncomingKeys inPrev = k.getPreviousIncomingKeys();
+			ps.setLong(3, inPrev.getRotationPeriod());
+			ps.setBytes(4, inPrev.getTagKey().getBytes());
+			ps.setBytes(5, inPrev.getHeaderKey().getBytes());
+			ps.setLong(6, inPrev.getWindowBase());
+			ps.setBytes(7, inPrev.getWindowBitmap());
+			ps.addBatch();
+			// Current rotation period
+			IncomingKeys inCurr = k.getCurrentIncomingKeys();
+			ps.setLong(3, inCurr.getRotationPeriod());
+			ps.setBytes(4, inCurr.getTagKey().getBytes());
+			ps.setBytes(5, inCurr.getHeaderKey().getBytes());
+			ps.setLong(6, inCurr.getWindowBase());
+			ps.setBytes(7, inCurr.getWindowBitmap());
+			ps.addBatch();
+			// Next rotation period
+			IncomingKeys inNext = k.getNextIncomingKeys();
+			ps.setLong(3, inNext.getRotationPeriod());
+			ps.setBytes(4, inNext.getTagKey().getBytes());
+			ps.setBytes(5, inNext.getHeaderKey().getBytes());
+			ps.setLong(6, inNext.getWindowBase());
+			ps.setBytes(7, inNext.getWindowBitmap());
+			ps.addBatch();
+			int[] batchAffected = ps.executeBatch();
+			if (batchAffected.length != 3) throw new DbStateException();
+			for (int rows : batchAffected)
+				if (rows != 1) throw new DbStateException();
+			ps.close();
+			// Store the outgoing keys
+			sql = "INSERT INTO outgoingKeys (contactId, transportId,"
+					+ " rotationPeriod, tagKey, headerKey, stream)"
+					+ " VALUES (?, ?, ?, ?, ?, ?)";
+			ps = txn.prepareStatement(sql);
+			ps.setInt(1, c.getInt());
+			ps.setString(2, k.getTransportId().getString());
 			OutgoingKeys outCurr = k.getCurrentOutgoingKeys();
 			ps.setLong(3, outCurr.getRotationPeriod());
 			ps.setBytes(4, outCurr.getTagKey().getBytes());
 			ps.setBytes(5, outCurr.getHeaderKey().getBytes());
 			ps.setLong(6, outCurr.getStreamCounter());
-			ps.setBoolean(7, outCurr.isActive());
 			int affected = ps.executeUpdate();
 			if (affected != 1) throw new DbStateException();
 			ps.close();
-			// Get the new (highest) key set ID
-			sql = "SELECT keySetId FROM outgoingKeys"
-					+ " ORDER BY keySetId DESC LIMIT 1";
-			ps = txn.prepareStatement(sql);
-			rs = ps.executeQuery();
-			if (!rs.next()) throw new DbStateException();
-			KeySetId keySetId = new KeySetId(rs.getInt(1));
-			if (rs.next()) throw new DbStateException();
-			rs.close();
-			ps.close();
-			// Store the incoming keys
-			sql = "INSERT INTO incomingKeys (keySetId, contactId, transportId,"
-					+ " rotationPeriod, tagKey, headerKey, base, bitmap,"
-					+ " periodOffset)"
-					+ " VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)";
-			ps = txn.prepareStatement(sql);
-			ps.setInt(1, keySetId.getInt());
-			ps.setInt(2, c.getInt());
-			ps.setString(3, k.getTransportId().getString());
-			// Previous rotation period
-			IncomingKeys inPrev = k.getPreviousIncomingKeys();
-			ps.setLong(4, inPrev.getRotationPeriod());
-			ps.setBytes(5, inPrev.getTagKey().getBytes());
-			ps.setBytes(6, inPrev.getHeaderKey().getBytes());
-			ps.setLong(7, inPrev.getWindowBase());
-			ps.setBytes(8, inPrev.getWindowBitmap());
-			ps.setInt(9, OFFSET_PREV);
-			ps.addBatch();
-			// Current rotation period
-			IncomingKeys inCurr = k.getCurrentIncomingKeys();
-			ps.setLong(4, inCurr.getRotationPeriod());
-			ps.setBytes(5, inCurr.getTagKey().getBytes());
-			ps.setBytes(6, inCurr.getHeaderKey().getBytes());
-			ps.setLong(7, inCurr.getWindowBase());
-			ps.setBytes(8, inCurr.getWindowBitmap());
-			ps.setInt(9, OFFSET_CURR);
-			ps.addBatch();
-			// Next rotation period
-			IncomingKeys inNext = k.getNextIncomingKeys();
-			ps.setLong(4, inNext.getRotationPeriod());
-			ps.setBytes(5, inNext.getTagKey().getBytes());
-			ps.setBytes(6, inNext.getHeaderKey().getBytes());
-			ps.setLong(7, inNext.getWindowBase());
-			ps.setBytes(8, inNext.getWindowBitmap());
-			ps.setInt(9, OFFSET_NEXT);
-			ps.addBatch();
-			int[] batchAffected = ps.executeBatch();
-			if (batchAffected.length != 3) throw new DbStateException();
-			for (int rows : batchAffected)
-				if (rows != 1) throw new DbStateException();
-			ps.close();
-			return keySetId;
 		} catch (SQLException e) {
-			tryToClose(rs);
 			tryToClose(ps);
 			throw new DbException(e);
 		}
@@ -1321,18 +1242,17 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT clientId, majorVersion, descriptor"
+			String sql = "SELECT clientId, descriptor FROM groups"
-					+ " FROM groups WHERE groupId = ?";
+					+ " WHERE groupId = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, g.getBytes());
 			rs = ps.executeQuery();
 			if (!rs.next()) throw new DbStateException();
 			ClientId clientId = new ClientId(rs.getString(1));
-			int majorVersion = rs.getInt(2);
+			byte[] descriptor = rs.getBytes(2);
-			byte[] descriptor = rs.getBytes(3);
 			rs.close();
 			ps.close();
-			return new Group(g, clientId, majorVersion, descriptor);
+			return new Group(g, clientId, descriptor);
 		} catch (SQLException e) {
 			tryToClose(rs);
 			tryToClose(ps);
@@ -1341,22 +1261,21 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public Collection<Group> getGroups(Connection txn, ClientId c,
+	public Collection<Group> getGroups(Connection txn, ClientId c)
-			int majorVersion) throws DbException {
+			throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
 			String sql = "SELECT groupId, descriptor FROM groups"
-					+ " WHERE clientId = ? AND majorVersion = ?";
+					+ " WHERE clientId = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, c.getString());
-			ps.setInt(2, majorVersion);
 			rs = ps.executeQuery();
 			List<Group> groups = new ArrayList<>();
 			while (rs.next()) {
 				GroupId id = new GroupId(rs.getBytes(1));
 				byte[] descriptor = rs.getBytes(2);
-				groups.add(new Group(id, c, majorVersion, descriptor));
+				groups.add(new Group(id, c, descriptor));
 			}
 			rs.close();
 			ps.close();
@@ -1488,11 +1407,32 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT messageId FROM messages"
+			String sql = "SELECT messageId FROM messages WHERE groupId = ?";
-					+ " WHERE groupId = ? AND state = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, g.getBytes());
-			ps.setInt(2, DELIVERED.getValue());
+			rs = ps.executeQuery();
+			List<MessageId> ids = new ArrayList<>();
+			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
+			rs.close();
+			ps.close();
+			return ids;
+		} catch (SQLException e) {
+			tryToClose(rs);
+			tryToClose(ps);
+			throw new DbException(e);
+		}
+	}
+
+	private Collection<MessageId> getMessageIds(Connection txn, GroupId g,
+			State state) throws DbException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT messageId FROM messages"
+					+ " WHERE state = ? AND groupId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setInt(1, state.getValue());
+			ps.setBytes(2, g.getBytes());
 			rs = ps.executeQuery();
 			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
@@ -1510,7 +1450,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 	public Collection<MessageId> getMessageIds(Connection txn, GroupId g,
 			Metadata query) throws DbException {
 		// If there are no query terms, return all delivered messages
-		if (query.isEmpty()) return getMessageIds(txn, g);
+		if (query.isEmpty()) return getMessageIds(txn, g, DELIVERED);
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
@@ -1669,11 +1609,10 @@ abstract class JdbcDatabase implements Database<Connection> {
 		ResultSet rs = null;
 		try {
 			String sql = "SELECT messageId, txCount > 0, seen FROM statuses"
-					+ " WHERE groupId = ? AND contactId = ? AND state = ?";
+					+ " WHERE groupId = ? AND contactId = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, g.getBytes());
 			ps.setInt(2, c.getInt());
-			ps.setInt(3, DELIVERED.getValue());
 			rs = ps.executeQuery();
 			List<MessageStatus> statuses = new ArrayList<>();
 			while (rs.next()) {
@@ -1693,29 +1632,24 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	@Nullable
 	public MessageStatus getMessageStatus(Connection txn, ContactId c,
 			MessageId m) throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
 			String sql = "SELECT txCount > 0, seen FROM statuses"
-					+ " WHERE messageId = ? AND contactId = ? AND state = ?";
+					+ " WHERE messageId = ? AND contactId = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			ps.setInt(2, c.getInt());
-			ps.setInt(3, DELIVERED.getValue());
 			rs = ps.executeQuery();
-			MessageStatus status = null;
+			if (!rs.next()) throw new DbStateException();
-			if (rs.next()) {
+			boolean sent = rs.getBoolean(1);
-				boolean sent = rs.getBoolean(1);
+			boolean seen = rs.getBoolean(2);
-				boolean seen = rs.getBoolean(2);
-				status = new MessageStatus(m, c, sent, seen);
-			}
 			if (rs.next()) throw new DbStateException();
 			rs.close();
 			ps.close();
-			return status;
+			return new MessageStatus(m, c, sent, seen);
 		} catch (SQLException e) {
 			tryToClose(rs);
 			tryToClose(ps);
@@ -1729,9 +1663,11 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT dependencyId, dependencyState"
+			String sql = "SELECT d.dependencyId, m.state, d.groupId, m.groupId"
-					+ " FROM messageDependencies"
+					+ " FROM messageDependencies AS d"
-					+ " WHERE messageId = ?";
+					+ " LEFT OUTER JOIN messages AS m"
+					+ " ON d.dependencyId = m.messageId"
+					+ " WHERE d.messageId = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			rs = ps.executeQuery();
@@ -1739,8 +1675,14 @@ abstract class JdbcDatabase implements Database<Connection> {
 			while (rs.next()) {
 				MessageId dependency = new MessageId(rs.getBytes(1));
 				State state = State.fromValue(rs.getInt(2));
-				if (rs.wasNull())
+				if (rs.wasNull()) {
-					state = UNKNOWN; // Missing or in a different group
+					state = UNKNOWN; // Missing dependency
+				} else {
+					GroupId dependentGroupId = new GroupId(rs.getBytes(3));
+					GroupId dependencyGroupId = new GroupId(rs.getBytes(4));
+					if (!dependentGroupId.equals(dependencyGroupId))
+						state = INVALID; // Dependency in another group
+				}
 				dependencies.put(dependency, state);
 			}
 			rs.close();
@@ -1759,12 +1701,11 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			// Exclude dependencies that are missing or in a different group
+			String sql = "SELECT d.messageId, m.state"
-			// from the dependent
+					+ " FROM messageDependencies AS d"
-			String sql = "SELECT messageId, messageState"
+					+ " JOIN messages AS m"
-					+ " FROM messageDependencies"
+					+ " ON d.messageId = m.messageId"
-					+ " WHERE dependencyId = ?"
+					+ " WHERE dependencyId = ?";
-					+ " AND dependencyState IS NOT NULL";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			rs = ps.executeQuery();
@@ -2103,8 +2044,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public Collection<KeySet> getTransportKeys(Connection txn, TransportId t)
+	public Map<ContactId, TransportKeys> getTransportKeys(Connection txn,
-			throws DbException {
+			TransportId t) throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
@@ -2113,7 +2054,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " base, bitmap"
 					+ " FROM incomingKeys"
 					+ " WHERE transportId = ?"
-					+ " ORDER BY keySetId, periodOffset";
+					+ " ORDER BY contactId, rotationPeriod";
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, t.getString());
 			rs = ps.executeQuery();
@@ -2130,33 +2071,29 @@ abstract class JdbcDatabase implements Database<Connection> {
 			rs.close();
 			ps.close();
 			// Retrieve the outgoing keys in the same order
-			sql = "SELECT keySetId, contactId, rotationPeriod,"
+			sql = "SELECT contactId, rotationPeriod, tagKey, headerKey, stream"
-					+ " tagKey, headerKey, stream, active"
 					+ " FROM outgoingKeys"
 					+ " WHERE transportId = ?"
-					+ " ORDER BY keySetId";
+					+ " ORDER BY contactId, rotationPeriod";
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, t.getString());
 			rs = ps.executeQuery();
-			Collection<KeySet> keys = new ArrayList<>();
+			Map<ContactId, TransportKeys> keys = new HashMap<>();
 			for (int i = 0; rs.next(); i++) {
 				// There should be three times as many incoming keys
 				if (inKeys.size() < (i + 1) * 3) throw new DbStateException();
-				KeySetId keySetId = new KeySetId(rs.getInt(1));
+				ContactId contactId = new ContactId(rs.getInt(1));
-				ContactId contactId = new ContactId(rs.getInt(2));
+				long rotationPeriod = rs.getLong(2);
-				long rotationPeriod = rs.getLong(3);
+				SecretKey tagKey = new SecretKey(rs.getBytes(3));
-				SecretKey tagKey = new SecretKey(rs.getBytes(4));
+				SecretKey headerKey = new SecretKey(rs.getBytes(4));
-				SecretKey headerKey = new SecretKey(rs.getBytes(5));
+				long streamCounter = rs.getLong(5);
-				long streamCounter = rs.getLong(6);
-				boolean active = rs.getBoolean(7);
 				OutgoingKeys outCurr = new OutgoingKeys(tagKey, headerKey,
-						rotationPeriod, streamCounter, active);
+						rotationPeriod, streamCounter);
 				IncomingKeys inPrev = inKeys.get(i * 3);
 				IncomingKeys inCurr = inKeys.get(i * 3 + 1);
 				IncomingKeys inNext = inKeys.get(i * 3 + 2);
-				TransportKeys transportKeys = new TransportKeys(t, inPrev,
+				keys.put(contactId, new TransportKeys(t, inPrev, inCurr,
-						inCurr, inNext, outCurr);
+						inNext, outCurr));
-				keys.add(new KeySet(keySetId, contactId, transportKeys));
 			}
 			rs.close();
 			ps.close();
@@ -2169,15 +2106,17 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public void incrementStreamCounter(Connection txn, TransportId t,
+	public void incrementStreamCounter(Connection txn, ContactId c,
-			KeySetId k) throws DbException {
+			TransportId t, long rotationPeriod) throws DbException {
 		PreparedStatement ps = null;
 		try {
 			String sql = "UPDATE outgoingKeys SET stream = stream + 1"
-					+ " WHERE transportId = ? AND keySetId = ?";
+					+ " WHERE contactId = ? AND transportId = ?"
+					+ " AND rotationPeriod = ?";
 			ps = txn.prepareStatement(sql);
-			ps.setString(1, t.getString());
+			ps.setInt(1, c.getInt());
-			ps.setInt(2, k.getInt());
+			ps.setString(2, t.getString());
+			ps.setLong(3, rotationPeriod);
 			int affected = ps.executeUpdate();
 			if (affected != 1) throw new DbStateException();
 			ps.close();
@@ -2534,14 +2473,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			if (affected != 1) throw new DbStateException();
 			ps.close();
 			// Remove status rows for the messages in the group
-			sql = "DELETE FROM statuses"
+			for (MessageId m : getMessageIds(txn, g)) removeStatus(txn, c, m);
-					+ " WHERE contactId = ? AND groupId = ?";
-			ps = txn.prepareStatement(sql);
-			ps.setInt(1, c.getInt());
-			ps.setBytes(2, g.getBytes());
-			affected = ps.executeUpdate();
-			if (affected < 0) throw new DbStateException();
-			ps.close();
 		} catch (SQLException e) {
 			tryToClose(ps);
 			throw new DbException(e);
@@ -2625,14 +2557,15 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
-	@Override
+	private void removeStatus(Connection txn, ContactId c, MessageId m)
-	public void removeTransport(Connection txn, TransportId t)
 			throws DbException {
 		PreparedStatement ps = null;
 		try {
-			String sql = "DELETE FROM transports WHERE transportId = ?";
+			String sql = "DELETE FROM statuses"
+					+ " WHERE messageId = ? AND contactId = ?";
 			ps = txn.prepareStatement(sql);
-			ps.setString(1, t.getString());
+			ps.setBytes(1, m.getBytes());
+			ps.setInt(2, c.getInt());
 			int affected = ps.executeUpdate();
 			if (affected != 1) throw new DbStateException();
 			ps.close();
@@ -2643,19 +2576,15 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public void removeTransportKeys(Connection txn, TransportId t, KeySetId k)
+	public void removeTransport(Connection txn, TransportId t)
 			throws DbException {
 		PreparedStatement ps = null;
 		try {
-			// Delete any existing outgoing keys - this will also remove any
+			String sql = "DELETE FROM transports WHERE transportId = ?";
-			// incoming keys with the same key set ID
-			String sql = "DELETE FROM outgoingKeys"
-					+ " WHERE transportId = ? AND keySetId = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, t.getString());
-			ps.setInt(2, k.getInt());
 			int affected = ps.executeUpdate();
-			if (affected < 0) throw new DbStateException();
+			if (affected != 1) throw new DbStateException();
 			ps.close();
 		} catch (SQLException e) {
 			tryToClose(ps);
@@ -2802,25 +2731,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 			affected = ps.executeUpdate();
 			if (affected < 0) throw new DbStateException();
 			ps.close();
-			// Update denormalised column in messageDependencies
-			sql = "UPDATE messageDependencies SET messageState = ?"
-					+ " WHERE messageId = ?";
-			ps = txn.prepareStatement(sql);
-			ps.setInt(1, state.getValue());
-			ps.setBytes(2, m.getBytes());
-			affected = ps.executeUpdate();
-			if (affected < 0) throw new DbStateException();
-			ps.close();
-			// Update denormalised column in messageDependencies if dependency
-			// is present and in same group as dependent
-			sql = "UPDATE messageDependencies SET dependencyState = ?"
-					+ " WHERE dependencyId = ? AND dependencyState IS NOT NULL";
-			ps = txn.prepareStatement(sql);
-			ps.setInt(1, state.getValue());
-			ps.setBytes(2, m.getBytes());
-			affected = ps.executeUpdate();
-			if (affected < 0) throw new DbStateException();
-			ps.close();
 		} catch (SQLException e) {
 			tryToClose(ps);
 			throw new DbException(e);
@@ -2828,18 +2738,18 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public void setReorderingWindow(Connection txn, KeySetId k, TransportId t,
+	public void setReorderingWindow(Connection txn, ContactId c, TransportId t,
 			long rotationPeriod, long base, byte[] bitmap) throws DbException {
 		PreparedStatement ps = null;
 		try {
 			String sql = "UPDATE incomingKeys SET base = ?, bitmap = ?"
-					+ " WHERE transportId = ? AND keySetId = ?"
+					+ " WHERE contactId = ? AND transportId = ?"
 					+ " AND rotationPeriod = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setLong(1, base);
 			ps.setBytes(2, bitmap);
-			ps.setString(3, t.getString());
+			ps.setInt(3, c.getInt());
-			ps.setInt(4, k.getInt());
+			ps.setString(4, t.getString());
 			ps.setLong(5, rotationPeriod);
 			int affected = ps.executeUpdate();
 			if (affected < 0 || affected > 1) throw new DbStateException();
@@ -2850,25 +2760,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
-	@Override
-	public void setTransportKeysActive(Connection txn, TransportId t,
-			KeySetId k) throws DbException {
-		PreparedStatement ps = null;
-		try {
-			String sql = "UPDATE outgoingKeys SET active = true"
-					+ " WHERE transportId = ? AND keySetId = ?";
-			ps = txn.prepareStatement(sql);
-			ps.setString(1, t.getString());
-			ps.setInt(2, k.getInt());
-			int affected = ps.executeUpdate();
-			if (affected < 0 || affected > 1) throw new DbStateException();
-			ps.close();
-		} catch (SQLException e) {
-			tryToClose(ps);
-			throw new DbException(e);
-		}
-	}
-
 	@Override
 	public void updateExpiryTime(Connection txn, ContactId c, MessageId m,
 			int maxLatency) throws DbException {
@@ -2904,69 +2795,45 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public void updateTransportKeys(Connection txn, KeySet ks)
+	public void updateTransportKeys(Connection txn,
-			throws DbException {
+			Map<ContactId, TransportKeys> keys) throws DbException {
 		PreparedStatement ps = null;
 		try {
-			// Update the outgoing keys
+			// Delete any existing incoming keys
-			String sql = "UPDATE outgoingKeys SET rotationPeriod = ?,"
+			String sql = "DELETE FROM incomingKeys"
-					+ " tagKey = ?, headerKey = ?, stream = ?"
+					+ " WHERE contactId = ?"
-					+ " WHERE transportId = ? AND keySetId = ?";
+					+ " AND transportId = ?";
 			ps = txn.prepareStatement(sql);
-			TransportKeys k = ks.getTransportKeys();
+			for (Entry<ContactId, TransportKeys> e : keys.entrySet()) {
-			OutgoingKeys outCurr = k.getCurrentOutgoingKeys();
+				ps.setInt(1, e.getKey().getInt());
-			ps.setLong(1, outCurr.getRotationPeriod());
+				ps.setString(2, e.getValue().getTransportId().getString());
-			ps.setBytes(2, outCurr.getTagKey().getBytes());
+				ps.addBatch();
-			ps.setBytes(3, outCurr.getHeaderKey().getBytes());
+			}
-			ps.setLong(4, outCurr.getStreamCounter());
-			ps.setString(5, k.getTransportId().getString());
-			ps.setInt(6, ks.getKeySetId().getInt());
-			int affected = ps.executeUpdate();
-			if (affected < 0 || affected > 1) throw new DbStateException();
-			ps.close();
-			// Update the incoming keys
-			sql = "UPDATE incomingKeys SET rotationPeriod = ?,"
-					+ " tagKey = ?, headerKey = ?, base = ?, bitmap = ?"
-					+ " WHERE transportId = ? AND keySetId = ?"
-					+ " AND periodOffset = ?";
-			ps = txn.prepareStatement(sql);
-			ps.setString(6, k.getTransportId().getString());
-			ps.setInt(7, ks.getKeySetId().getInt());
-			// Previous rotation period
-			IncomingKeys inPrev = k.getPreviousIncomingKeys();
-			ps.setLong(1, inPrev.getRotationPeriod());
-			ps.setBytes(2, inPrev.getTagKey().getBytes());
-			ps.setBytes(3, inPrev.getHeaderKey().getBytes());
-			ps.setLong(4, inPrev.getWindowBase());
-			ps.setBytes(5, inPrev.getWindowBitmap());
-			ps.setInt(8, OFFSET_PREV);
-			ps.addBatch();
-			// Current rotation period
-			IncomingKeys inCurr = k.getCurrentIncomingKeys();
-			ps.setLong(1, inCurr.getRotationPeriod());
-			ps.setBytes(2, inCurr.getTagKey().getBytes());
-			ps.setBytes(3, inCurr.getHeaderKey().getBytes());
-			ps.setLong(4, inCurr.getWindowBase());
-			ps.setBytes(5, inCurr.getWindowBitmap());
-			ps.setInt(8, OFFSET_CURR);
-			ps.addBatch();
-			// Next rotation period
-			IncomingKeys inNext = k.getNextIncomingKeys();
-			ps.setLong(1, inNext.getRotationPeriod());
-			ps.setBytes(2, inNext.getTagKey().getBytes());
-			ps.setBytes(3, inNext.getHeaderKey().getBytes());
-			ps.setLong(4, inNext.getWindowBase());
-			ps.setBytes(5, inNext.getWindowBitmap());
-			ps.setInt(8, OFFSET_NEXT);
-			ps.addBatch();
 			int[] batchAffected = ps.executeBatch();
-			if (batchAffected.length != 3) throw new DbStateException();
+			if (batchAffected.length != keys.size())
-			for (int rows : batchAffected)
+				throw new DbStateException();
-				if (rows < 0 || rows > 1) throw new DbStateException();
+			ps.close();
+			// Delete any existing outgoing keys
+			sql = "DELETE FROM outgoingKeys"
+					+ " WHERE contactId = ?"
+					+ " AND transportId = ?";
+			ps = txn.prepareStatement(sql);
+			for (Entry<ContactId, TransportKeys> e : keys.entrySet()) {
+				ps.setInt(1, e.getKey().getInt());
+				ps.setString(2, e.getValue().getTransportId().getString());
+				ps.addBatch();
+			}
+			batchAffected = ps.executeBatch();
+			if (batchAffected.length != keys.size())
+				throw new DbStateException();
 			ps.close();
 		} catch (SQLException e) {
 			tryToClose(ps);
 			throw new DbException(e);
 		}
+		// Store the new keys
+		for (Entry<ContactId, TransportKeys> e : keys.entrySet()) {
+			addTransportKeys(txn, e.getKey(), e.getValue());
+		}
 	}
 }