WIP make part of keyAgreement public, so it can be used for shard return

* 'social-backup-poc' of https://code.briarproject.org/briar/briar:
  Inject social backup eager singletons when Briar core is created.

.gitlab-ci.yml

@@ -2,6 +2,7 @@ image: briar/ci-image-android:latest
 
 stages:
 - test
+- optional_tests
 - check_reproducibility
 
 test:
@@ -31,3 +32,33 @@ test_reproducible:
     - "curl -X POST -F token=${RELEASE_CHECK_TOKEN} -F ref=master -F variables[RELEASE_TAG]=${CI_COMMIT_REF_NAME} https://code.briarproject.org/api/v4/projects/61/trigger/pipeline"
   only:
     - tags
+
+.optional_tests:
+  stage: optional_tests
+  before_script:
+    - set -e
+    - export GRADLE_USER_HOME=$PWD/.gradle
+
+  cache:
+    paths:
+      - .gradle/wrapper
+      - .gradle/caches
+
+  script:
+    - OPTIONAL_TESTS=org.briarproject.bramble.plugin.tor.BridgeTest ./gradlew --info bramble-java:test --tests BridgeTest
+
+  after_script:
+    # these file change 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/
+
+manual_tests:
+  extends: .optional_tests
+  when: manual
+  except:
+    - tags
+
+pre_release_tests:
+  extends: .optional_tests
+  only:
+    - tags

.idea/dictionaries/briar.xml

@@ -0,0 +1,14 @@
+<component name="ProjectDictionaryState">
+  <dictionary name="briar">
+    <words>
+      <w>briar</w>
+      <w>briarproject</w>
+      <w>emoji</w>
+      <w>encrypter</w>
+      <w>identicon</w>
+      <w>introducee</w>
+      <w>introducer</w>
+      <w>onboarding</w>
+    </words>
+  </dictionary>
+</component>

.idea/runConfigurations/BridgeTest.xml

@@ -0,0 +1,24 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="BridgeTest" type="AndroidJUnit" factoryName="Android JUnit" nameIsGenerated="true">
+    <module name="briar.bramble-java" />
+    <useClassPathOnly />
+    <extension name="coverage">
+      <pattern>
+        <option name="PATTERN" value="org.briarproject.bramble.plugin.tor.*" />
+        <option name="ENABLED" value="true" />
+      </pattern>
+    </extension>
+    <option name="PACKAGE_NAME" value="org.briarproject.bramble.plugin.tor" />
+    <option name="MAIN_CLASS_NAME" value="org.briarproject.bramble.plugin.tor.BridgeTest" />
+    <option name="METHOD_NAME" value="" />
+    <option name="TEST_OBJECT" value="class" />
+    <option name="PARAMETERS" value="" />
+    <option name="WORKING_DIRECTORY" value="$MODULE_DIR$" />
+    <envs>
+      <env name="OPTIONAL_TESTS" value="org.briarproject.bramble.plugin.tor.BridgeTest" />
+    </envs>
+    <method v="2">
+      <option name="Android.Gradle.BeforeRunTask" enabled="true" />
+    </method>
+  </configuration>
+</component>

bramble-android/build.gradle

@@ -11,8 +11,8 @@ android {
 	defaultConfig {
 		minSdkVersion 16
 		targetSdkVersion 29
-		versionCode 10213
-		versionName "1.2.13"
+		versionCode 10216
+		versionName "1.2.16"
 		consumerProguardFiles 'proguard-rules.txt'
 
 		testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
@@ -38,8 +38,8 @@ configurations {
 
 dependencies {
 	implementation project(path: ':bramble-core', configuration: 'default')
-	tor 'org.briarproject:tor-android:0.3.5.12@zip'
-	tor 'org.briarproject:obfs4proxy-android:0.0.11-2@zip'
+	tor 'org.briarproject:tor-android:0.3.5.13@zip'
+	tor 'org.briarproject:obfs4proxy-android:0.0.12-dev-40245c4a@zip'
 
 	annotationProcessor 'com.google.dagger:dagger-compiler:2.24'
 

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

@@ -31,6 +31,7 @@ public class AndroidUtils {
 	private static final String FAKE_BLUETOOTH_ADDRESS = "02:00:00:00:00:00";
 
 	private static final String STORED_REPORTS = "dev-reports";
+	private static final String STORED_LOGCAT = "dev-logcat";
 
 	public static Collection<String> getSupportedArchitectures() {
 		List<String> abis = new ArrayList<>();
@@ -107,6 +108,10 @@ public class AndroidUtils {
 		return ctx.getDir(STORED_REPORTS, MODE_PRIVATE);
 	}
 
+	public static File getLogcatFile(Context ctx) {
+		return new File(ctx.getFilesDir(), STORED_LOGCAT);
+	}
+
 	/**
 	 * Returns an array of supported content types for image attachments.
 	 * GIFs can't be compressed on API < 24 so they're not supported.

bramble-android/witness.gradle

@@ -75,8 +75,8 @@ dependencyVerification {
         'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
         'org.bouncycastle:bcpkix-jdk15on:1.56:bcpkix-jdk15on-1.56.jar:7043dee4e9e7175e93e0b36f45b1ec1ecb893c5f755667e8b916eb8dd201c6ca',
         'org.bouncycastle:bcprov-jdk15on:1.56:bcprov-jdk15on-1.56.jar:963e1ee14f808ffb99897d848ddcdb28fa91ddda867eb18d303e82728f878349',
-        'org.briarproject:obfs4proxy-android:0.0.11-2:obfs4proxy-android-0.0.11-2.zip:57e55cbe87aa2aac210fdbb6cd8cdeafe15f825406a08ebf77a8b787aa2c6a8a',
-        'org.briarproject:tor-android:0.3.5.12:tor-android-0.3.5.12.zip:db71fb3290acff79d572af0752570eaf6aad7c4d88c9b9aa0b4d5afe2b9ead9c',
+        'org.briarproject:obfs4proxy-android:0.0.12-dev-40245c4a:obfs4proxy-android-0.0.12-dev-40245c4a.zip:8ab05a8f8391be2cb5ab2b665c281a06d9e3a756bd0f95a40a36ca927866ea82',
+        'org.briarproject:tor-android:0.3.5.13:tor-android-0.3.5.13.zip:e0978db136731dae07774b722970cdae1e462fb5adc82845dd80a7e2d87f356c',
         'org.checkerframework:checker-compat-qual:2.5.3:checker-compat-qual-2.5.3.jar:d76b9afea61c7c082908023f0cbc1427fab9abd2df915c8b8a3e7a509bccbc6d',
         'org.checkerframework:checker-qual:2.5.2:checker-qual-2.5.2.jar:64b02691c8b9d4e7700f8ee2e742dce7ea2c6e81e662b7522c9ee3bf568c040a',
         'org.checkerframework:checker-qual:2.8.1:checker-qual-2.8.1.jar:9103499008bcecd4e948da29b17864abb64304e15706444ae209d17ebe0575df',

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

@@ -1,12 +1,11 @@
-package org.briarproject.bramble.crypto;
+package org.briarproject.bramble.api.crypto;
 
-import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.security.GeneralSecurityException;
 
 @NotNullByDefault
-interface AuthenticatedCipher {
+public interface AuthenticatedCipher {
 
 	/**
 	 * Initializes this cipher for encryption or decryption with a key and an

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

@@ -19,4 +19,10 @@ public interface StreamDecrypterFactory {
 	 */
 	StreamDecrypter createContactExchangeStreamDecrypter(InputStream in,
 			SecretKey headerKey);
+
+	/**
+	 * Creates a {@link StreamDecrypter} for decrypting a log stream.
+	 */
+	StreamDecrypter createLogStreamDecrypter(InputStream in,
+			SecretKey headerKey);
 }

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

@@ -17,6 +17,12 @@ public interface StreamEncrypterFactory {
 	 * Creates a {@link StreamEncrypter} for encrypting a contact exchange
 	 * stream.
 	 */
-	StreamEncrypter createContactExchangeStreamDecrypter(OutputStream out,
+	StreamEncrypter createContactExchangeStreamEncrypter(OutputStream out,
+			SecretKey headerKey);
+
+	/**
+	 * Creates a {@link StreamEncrypter} for encrypting a log stream.
+	 */
+	StreamEncrypter createLogStreamEncrypter(OutputStream out,
 			SecretKey headerKey);
 }

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

@@ -26,6 +26,11 @@ public interface IdentityManager {
 	 */
 	void registerIdentity(Identity i);
 
+	/**
+	 * Returns the cached local identity or loads it from the database.
+	 */
+	Identity getIdentity(Transaction txn) throws DbException;
+
 	/**
 	 * Returns the cached local identity or loads it from the database.
 	 */

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

@@ -74,6 +74,13 @@ public interface TransportPropertyManager {
 	TransportProperties getRemoteProperties(ContactId c, TransportId t)
 			throws DbException;
 
+	/**
+	 * Returns the remote transport properties for the given contact and
+	 * transport.
+	 */
+	TransportProperties getRemoteProperties(Transaction txn, ContactId c,
+			TransportId t) throws DbException;
+
 	/**
 	 * Merges the given properties with the existing local properties for the
 	 * given transport.

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

@@ -13,4 +13,6 @@ public interface DevConfig {
 	String getDevOnionAddress();
 
 	File getReportDir();
+
+	File getLogcatFile();
 }

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

@@ -16,8 +16,13 @@ public interface StreamReaderFactory {
 
 	/**
 	 * Creates an {@link InputStream InputStream} for reading from a contact
-	 * exchangestream.
+	 * exchange stream.
 	 */
 	InputStream createContactExchangeStreamReader(InputStream in,
 			SecretKey headerKey);
+
+	/**
+	 * Creates an {@link InputStream} for reading from a log stream.
+	 */
+	InputStream createLogStreamReader(InputStream in, SecretKey headerKey);
 }

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

@@ -7,17 +7,19 @@ import java.io.OutputStream;
 
 @NotNullByDefault
 public interface StreamWriterFactory {
-
 	/**
-	 * Creates an {@link OutputStream OutputStream} for writing to a
-	 * transport stream
+	 * Creates a {@link StreamWriter} for writing to a transport stream.
 	 */
 	StreamWriter createStreamWriter(OutputStream out, StreamContext ctx);
 
 	/**
-	 * Creates an {@link OutputStream OutputStream} for writing to a contact
-	 * exchange stream.
+	 * Creates a {@link StreamWriter} for writing to a contact exchange stream.
 	 */
 	StreamWriter createContactExchangeStreamWriter(OutputStream out,
 			SecretKey headerKey);
+
+	/**
+	 * Creates a {@link StreamWriter} for writing to a log stream.
+	 */
+	StreamWriter createLogStreamWriter(OutputStream out, SecretKey headerKey);
 }

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

@@ -6,6 +6,7 @@ import net.i2p.crypto.eddsa.KeyPairGenerator;
 
 import org.briarproject.bramble.api.crypto.AgreementPrivateKey;
 import org.briarproject.bramble.api.crypto.AgreementPublicKey;
+import org.briarproject.bramble.api.crypto.AuthenticatedCipher;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.DecryptionException;
 import org.briarproject.bramble.api.crypto.KeyPair;

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

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.crypto;
 
+import org.briarproject.bramble.api.crypto.AuthenticatedCipher;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.KeyAgreementCrypto;
 import org.briarproject.bramble.api.crypto.PasswordStrengthEstimator;

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

@@ -9,14 +9,16 @@ import java.util.logging.Logger;
 
 import javax.inject.Inject;
 
+import static java.lang.Math.min;
 import static java.util.logging.Level.INFO;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.now;
 
 class ScryptKdf implements PasswordBasedKdf {
 
 	private static final Logger LOG =
-			Logger.getLogger(ScryptKdf.class.getName());
+			getLogger(ScryptKdf.class.getName());
 
 	private static final int MIN_COST = 256; // Min parameter N
 	private static final int MAX_COST = 1024 * 1024; // Max parameter N
@@ -33,10 +35,20 @@ class ScryptKdf implements PasswordBasedKdf {
 
 	@Override
 	public int chooseCostParameter() {
+		// Scrypt uses at least 128 * N * r bytes of memory. Don't use more
+		// than half of the JVM's max heap size or we may run out of memory.
+		// https://blog.filippo.io/the-scrypt-parameters/
+		long maxMemory = Runtime.getRuntime().maxMemory();
+		long maxCost = min(MAX_COST, maxMemory / BLOCK_SIZE / 256);
+		if (LOG.isLoggable(INFO) && maxCost < MAX_COST) {
+			LOG.info("Max cost capped at " + maxCost
+					+ " due to max heap size " + maxMemory);
+		}
 		// Increase the cost from min to max while measuring performance
 		int cost = MIN_COST;
-		while (cost * 2 <= MAX_COST && measureDuration(cost) * 2 <= TARGET_MS)
+		while (cost * 2 <= maxCost && measureDuration(cost) * 2 <= TARGET_MS) {
 			cost *= 2;
+		}
 		if (LOG.isLoggable(INFO))
 			LOG.info("KDF cost parameter " + cost);
 		return cost;

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

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.crypto;
 
+import org.briarproject.bramble.api.crypto.AuthenticatedCipher;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.crypto.StreamDecrypter;
 import org.briarproject.bramble.api.crypto.StreamDecrypterFactory;
@@ -36,4 +37,10 @@ class StreamDecrypterFactoryImpl implements StreamDecrypterFactory {
 			SecretKey headerKey) {
 		return new StreamDecrypterImpl(in, cipherProvider.get(), 0, headerKey);
 	}
+
+	@Override
+	public StreamDecrypter createLogStreamDecrypter(InputStream in,
+			SecretKey headerKey) {
+		return createContactExchangeStreamDecrypter(in, headerKey);
+	}
 }

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

@@ -1,6 +1,7 @@
 package org.briarproject.bramble.crypto;
 
 import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.crypto.AuthenticatedCipher;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.crypto.StreamDecrypter;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;

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

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.crypto;
 
+import org.briarproject.bramble.api.crypto.AuthenticatedCipher;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.crypto.StreamEncrypter;
@@ -51,7 +52,7 @@ class StreamEncrypterFactoryImpl implements StreamEncrypterFactory {
 	}
 
 	@Override
-	public StreamEncrypter createContactExchangeStreamDecrypter(
+	public StreamEncrypter createContactExchangeStreamEncrypter(
 			OutputStream out, SecretKey headerKey) {
 		AuthenticatedCipher cipher = cipherProvider.get();
 		byte[] streamHeaderNonce = new byte[STREAM_HEADER_NONCE_LENGTH];
@@ -60,4 +61,10 @@ class StreamEncrypterFactoryImpl implements StreamEncrypterFactory {
 		return new StreamEncrypterImpl(out, cipher, 0, null, streamHeaderNonce,
 				headerKey, frameKey);
 	}
+
+	@Override
+	public StreamEncrypter createLogStreamEncrypter(OutputStream out,
+			SecretKey headerKey) {
+		return createContactExchangeStreamEncrypter(out, headerKey);
+	}
 }

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

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.crypto;
 
+import org.briarproject.bramble.api.crypto.AuthenticatedCipher;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.crypto.StreamEncrypter;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;

bramble-core/src/main/java/org/briarproject/bramble/crypto/XSalsa20Poly1305AuthenticatedCipher.java

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.crypto;
 
+import org.briarproject.bramble.api.crypto.AuthenticatedCipher;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.spongycastle.crypto.DataLengthException;

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

@@ -118,6 +118,11 @@ class IdentityManagerImpl implements IdentityManager, OpenDatabaseHook {
 		return cached.getLocalAuthor();
 	}
 
+	@Override
+	public Identity getIdentity(Transaction txn) throws DbException {
+		return getCachedIdentity(txn);
+	}
+
 	@Override
 	public LocalAuthor getLocalAuthor(Transaction txn) throws DbException {
 		return getCachedIdentity(txn).getLocalAuthor();

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

@@ -294,7 +294,13 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	public TransportProperties getRemoteProperties(ContactId c, TransportId t)
 			throws DbException {
 		return db.transactionWithResult(true, txn ->
-				getRemoteProperties(txn, db.getContact(txn, c), t));
+				getRemoteProperties(txn, c, t));
+	}
+
+	@Override
+	public TransportProperties getRemoteProperties(Transaction txn,
+			ContactId c, TransportId t) throws DbException {
+		return getRemoteProperties(txn, db.getContact(txn, c), t);
 	}
 
 	@Override

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

@@ -24,15 +24,21 @@ class StreamReaderFactoryImpl implements StreamReaderFactory {
 
 	@Override
 	public InputStream createStreamReader(InputStream in, StreamContext ctx) {
-		return new StreamReaderImpl(
-				streamDecrypterFactory.createStreamDecrypter(in, ctx));
+		return new StreamReaderImpl(streamDecrypterFactory
+				.createStreamDecrypter(in, ctx));
 	}
 
 	@Override
 	public InputStream createContactExchangeStreamReader(InputStream in,
 			SecretKey headerKey) {
-		return new StreamReaderImpl(
-				streamDecrypterFactory.createContactExchangeStreamDecrypter(in,
-						headerKey));
+		return new StreamReaderImpl(streamDecrypterFactory
+				.createContactExchangeStreamDecrypter(in, headerKey));
+	}
+
+	@Override
+	public InputStream createLogStreamReader(InputStream in,
+			SecretKey headerKey) {
+		return new StreamReaderImpl(streamDecrypterFactory
+				.createLogStreamDecrypter(in, headerKey));
 	}
 }

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

@@ -26,15 +26,21 @@ class StreamWriterFactoryImpl implements StreamWriterFactory {
 	@Override
 	public StreamWriter createStreamWriter(OutputStream out,
 			StreamContext ctx) {
-		return new StreamWriterImpl(
-				streamEncrypterFactory.createStreamEncrypter(out, ctx));
+		return new StreamWriterImpl(streamEncrypterFactory
+				.createStreamEncrypter(out, ctx));
 	}
 
 	@Override
 	public StreamWriter createContactExchangeStreamWriter(OutputStream out,
 			SecretKey headerKey) {
-		return new StreamWriterImpl(
-				streamEncrypterFactory.createContactExchangeStreamDecrypter(out,
-						headerKey));
+		return new StreamWriterImpl(streamEncrypterFactory
+				.createContactExchangeStreamEncrypter(out, headerKey));
 	}
-}
+
+	@Override
+	public StreamWriter createLogStreamWriter(OutputStream out,
+			SecretKey headerKey) {
+		return new StreamWriterImpl(streamEncrypterFactory
+				.createLogStreamEncrypter(out, headerKey));
+	}
+}

bramble-core/src/main/resources/bridges

@@ -1,5 +1,14 @@
+Bridge obfs4 192.95.36.142:443 CDF2E852BF539B82BD10E27E9115A31734E378C2 cert=qUVQ0srL1JI/vO6V6m/24anYXiJD3QP2HgzUKQtQ7GRqqUvs7P+tG43RtAqdhLOALP7DJQ iat-mode=1
+Bridge obfs4 38.229.1.78:80 C8CBDB2464FC9804A69531437BCF2BE31FDD2EE4 cert=Hmyfd2ev46gGY7NoVxA9ngrPF2zCZtzskRTzoWXbxNkzeVnGFPWmrTtILRyqCTjHR+s9dg iat-mode=1
+Bridge obfs4 37.218.245.14:38224 D9A82D2F9C2F65A18407B1D2B764F130847F8B5D cert=bjRaMrr1BRiAW8IE9U5z27fQaYgOhX1UCmOpg2pFpoMvo6ZgQMzLsaTzzQNTlm7hNcb+Sg iat-mode=0
+Bridge obfs4 85.31.186.98:443 011F2599C0E9B27EE74B353155E244813763C3E5 cert=ayq0XzCwhpdysn5o0EyDUbmSOx3X/oTEbzDMvczHOdBJKlvIdHHLJGkZARtT4dcBFArPPg iat-mode=0
+Bridge obfs4 85.31.186.26:443 91A6354697E6B02A386312F68D82CF86824D3606 cert=PBwr+S8JTVZo6MPdHnkTwXJPILWADLqfMGoVvhZClMq/Urndyd42BwX9YFJHZnBB3H0XCw iat-mode=0
+Bridge obfs4 193.11.166.194:27015 2D82C2E354D531A68469ADF7F878FA6060C6BACA cert=4TLQPJrTSaDffMK7Nbao6LC7G9OW/NHkUwIdjLSS3KYf0Nv4/nQiiI8dY2TcsQx01NniOg iat-mode=0
+Bridge obfs4 193.11.166.194:27020 86AC7B8D430DAC4117E9F42C9EAED18133863AAF cert=0LDeJH4JzMDtkJJrFphJCiPqKx7loozKN7VNfuukMGfHO0Z8OGdzHVkhVAOfo1mUdv9cMg iat-mode=0
+Bridge obfs4 193.11.166.194:27025 1AE2C08904527FEA90C4C4F8C1083EA59FBC6FAF cert=ItvYZzW5tn6v3G4UnQa6Qz04Npro6e81AP70YujmK/KXwDFPTs3aHXcHp4n8Vt6w/bv8cA iat-mode=0
+Bridge obfs4 209.148.46.65:443 74FAD13168806246602538555B5521A0383A1875 cert=ssH+9rP8dG2NLDN2XuFw63hIO/9MNNinLmxQDpVa+7kTOa9/m+tGWT1SmSYpQ9uTBGa6Hw iat-mode=0
+Bridge obfs4 146.57.248.225:22 10A6CD36A537FCE513A322361547444B393989F0 cert=K1gDtDAIcUfeLqbstggjIw2rtgIKqdIhUlHp82XRqNSq/mtAjp1BIC9vHKJ2FAEpGssTPw iat-mode=0
+Bridge obfs4 45.145.95.6:27015 C5B7CD6946FF10C5B3E89691A7D3F2C122D2117C cert=TD7PbUO0/0k6xYHMPW3vJxICfkMZNdkRrb63Zhl5j9dW3iRGiCx0A7mPhe5T2EDzQ35+Zw iat-mode=0
+Bridge obfs4 51.222.13.177:80 5EDAC3B810E12B01F6FD8050D2FD3E277B289A08 cert=2uplIpLQ0q9+0qMFrK5pkaYRDOe460LL9WHBvatgkuRr/SL31wBOEupaMMJ6koRE6Ld0ew iat-mode=0
 Bridge obfs4 78.46.188.239:37356 5A2D2F4158D0453E00C7C176978D3F41D69C45DB cert=3c0SwxpOisbohNxEc4tb875RVW8eOu1opRTVXJhafaKA/PNNtI7ElQIVOVZg1AdL5bxGCw iat-mode=0
-Bridge obfs4 52.15.78.72:9443 02069A3C5362476936B62BA6F5ACC41ABD573A9B cert=ijYG/OKc7kqu2YzKNFfeXN7/BG2BOgfEP2KyYEiGDQthnHbsOiTWHeIG0WJVW+BckzDgKw iat-mode=0
-Bridge obfs4 13.58.29.242:9443 0C58939A77DA6B6B29D4B5236A75865659607AE0 cert=OylWIEHb/ezpq1zWxW0sgKRn+9ARH2eOcQOZ8/Gew+4l+oKOhQ2jUX/Y+FSl61JorXZUWA iat-mode=0
-Bridge obfs4 45.33.37.112:9443 60A609BB4ABE8D46E634AE81ED29ADAB7776B399 cert=t5v19WmNv5Sc2YPNr8RQids365W7MY8zJwQVkOxBjUMFomMWARDzsbYpcWLLcw0J9Gm+BQ iat-mode=0
-Bridge meek_lite 0.0.2.0:2 97700DFE9F483596DDA6264C4D7DF7641E1E39CE url=https://meek.azureedge.net/ front=ajax.aspnetcdn.com
+Bridge meek_lite 192.0.2.2:2 97700DFE9F483596DDA6264C4D7DF7641E1E39CE url=https://meek.azureedge.net/ front=ajax.aspnetcdn.com

bramble-core/src/test/java/org/briarproject/bramble/crypto/StreamDecrypterImplTest.java

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.crypto;
 
+import org.briarproject.bramble.api.crypto.AuthenticatedCipher;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.test.BrambleTestCase;
 import org.briarproject.bramble.test.TestUtils;

bramble-core/src/test/java/org/briarproject/bramble/crypto/StreamEncrypterImplTest.java

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.crypto;
 
+import org.briarproject.bramble.api.crypto.AuthenticatedCipher;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.test.BrambleTestCase;
 import org.briarproject.bramble.test.TestUtils;

bramble-core/src/test/java/org/briarproject/bramble/crypto/TestAuthenticatedCipher.java

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.crypto;
 
+import org.briarproject.bramble.api.crypto.AuthenticatedCipher;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 

bramble-core/src/test/java/org/briarproject/bramble/crypto/XSalsa20Poly1305AuthenticatedCipherTest.java

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.crypto;
 
+import org.briarproject.bramble.api.crypto.AuthenticatedCipher;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.test.BrambleTestCase;
 import org.briarproject.bramble.util.StringUtils;

bramble-java/build.gradle

@@ -16,8 +16,8 @@ dependencies {
 	implementation fileTree(dir: 'libs', include: '*.jar')
 	implementation 'net.java.dev.jna:jna:4.5.2'
 	implementation 'net.java.dev.jna:jna-platform:4.5.2'
-	tor 'org.briarproject:tor:0.3.5.12@zip'
-	tor 'org.briarproject:obfs4proxy:0.0.7@zip'
+	tor 'org.briarproject:tor:0.3.5.13@zip'
+	tor 'org.briarproject:obfs4proxy:0.0.12-dev-40245c4a@zip'
 
 	annotationProcessor 'com.google.dagger:dagger-compiler:2.24'
 

bramble-java/src/test/java/org/briarproject/bramble/plugin/tor/BridgeTest.java

@@ -53,7 +53,7 @@ public class BridgeTest extends BrambleTestCase {
 		return component.getCircumventionProvider().getBridges(false);
 	}
 
-	private final static long TIMEOUT = SECONDS.toMillis(30);
+	private final static long TIMEOUT = SECONDS.toMillis(60);
 
 	private final static Logger LOG = getLogger(BridgeTest.class.getName());
 

bramble-java/witness.gradle

@@ -23,8 +23,8 @@ 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.briarproject:obfs4proxy:0.0.7:obfs4proxy-0.0.7.zip:5b2f693262ce43a7e130f7cc7d5d1617925330640a2eb6d71085e95df8ee0642',
-        'org.briarproject:tor:0.3.5.12:tor-0.3.5.12.zip:2f542c4befd216f2226bf7c76e3b8b2d99af6f146a8cb28bf727f42014587006',
+        'org.briarproject:obfs4proxy:0.0.12-dev-40245c4a:obfs4proxy-0.0.12-dev-40245c4a.zip:172029e7058b3a83ac93ac4991a44bf76e16ce8d46f558f5836d57da3cb3a766',
+        'org.briarproject:tor:0.3.5.13:tor-0.3.5.13.zip:1c5f0b821ee2aadb0ea04aa96caab3ca0a08370cce8de81c2dfe04d172f8a2a0',
         'org.checkerframework:checker-compat-qual:2.5.3:checker-compat-qual-2.5.3.jar:d76b9afea61c7c082908023f0cbc1427fab9abd2df915c8b8a3e7a509bccbc6d',
         'org.checkerframework:checker-qual:2.5.2:checker-qual-2.5.2.jar:64b02691c8b9d4e7700f8ee2e742dce7ea2c6e81e662b7522c9ee3bf568c040a',
         'org.codehaus.mojo:animal-sniffer-annotations:1.17:animal-sniffer-annotations-1.17.jar:92654f493ecfec52082e76354f0ebf87648dc3d5cec2e3c3cdb947c016747a53',

briar-android/artwork/notification_signout.svg

@@ -0,0 +1 @@
+<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" width="24" height="24" viewBox="0 0 24 24"><path d="M16,17V14H9V10H16V7L21,12L16,17M14,2A2,2 0 0,1 16,4V6H14V4H5V20H14V18H16V20A2,2 0 0,1 14,22H5A2,2 0 0,1 3,20V4A2,2 0 0,1 5,2H14Z" /></svg>

briar-android/build.gradle

@@ -22,9 +22,11 @@ android {
 	defaultConfig {
 		minSdkVersion 16
 		targetSdkVersion 29
-		versionCode 10213
-		versionName "1.2.13"
-		applicationId "org.briarproject.briar.android"
+		versionCode 10216
+		versionName "1.2.16"
+		applicationId "org.briarproject.briar.socialbackup"
+
+		vectorDrawables.useSupportLibrary = true
 		buildConfigField "String", "GitHash",
 				"\"${getStdout(['git', 'rev-parse', '--short=7', 'HEAD'], 'No commit hash')}\""
 		def now = (long) (System.currentTimeMillis() / 1000)
@@ -99,6 +101,7 @@ dependencies {
 	implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
 	implementation 'com.google.android.material:material:1.2.1'
 	implementation 'androidx.recyclerview:recyclerview-selection:1.1.0-rc03'
+	implementation 'org.magmacollective.darkcrystal:dark-crystal-secret-sharing-wrapper:1.1.0'
 
 	implementation 'info.guardianproject.panic:panic:1.0'
 	implementation 'info.guardianproject.trustedintents:trustedintents:0.2'
@@ -134,6 +137,7 @@ dependencies {
 	testImplementation "org.jmock:jmock:$jmockVersion"
 	testImplementation "org.jmock:jmock-junit4:$jmockVersion"
 	testImplementation "org.jmock:jmock-legacy:$jmockVersion"
+	testAnnotationProcessor "com.google.dagger:dagger-compiler:2.24"
 
 	androidTestImplementation project(path: ':bramble-api', configuration: 'testOutput')
 	androidTestImplementation 'androidx.test.ext:junit:1.1.2'

briar-android/proguard-rules.txt

@@ -40,3 +40,5 @@
 
 # Dependency injection annotations, needed for UI tests on older API levels
 -keep class javax.inject.**
+
+-keep class com.sun.jna.** { *; }

briar-android/src/debug/res/values/strings.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-	<string name="app_name" translatable="false">Briar Debug</string>
-	<string name="app_package" translatable="false">org.briarproject.briar.android.debug</string>
+	<string name="app_name" translatable="false">Briar SB Debug</string>
+	<string name="app_package" translatable="false">org.briarproject.briar.socialbackup.debug</string>
 </resources>

briar-android/src/main/AndroidManifest.xml

@@ -134,6 +134,42 @@
 			</intent-filter>
 		</activity>
 
+		<activity
+			android:name="org.briarproject.briar.android.account.NewOrRecoverActivity"
+			android:label="@string/activity_name_new_or_recover_account"
+			android:parentActivityName="org.briarproject.briar.android.login.StartupActivity">
+			<meta-data
+				android:name="android.support.PARENT_ACTIVITY"
+				android:value="org.briarproject.briar.android.login.StartupActivity" />
+		</activity>
+
+		<activity
+			android:name="org.briarproject.briar.android.socialbackup.DistributedBackupActivity"
+			android:label="@string/activity_name_distributed_backup"
+			android:parentActivityName="org.briarproject.briar.android.settings.SettingsActivity">
+			<meta-data
+				android:name="android.support.PARENT_ACTIVITY"
+				android:value="org.briarproject.briar.android.settings.SettingsActivity" />
+		</activity>
+
+		<activity
+			android:name="org.briarproject.briar.android.socialbackup.RecoverActivity"
+			android:label="@string/activity_name_recovery"
+			android:parentActivityName="org.briarproject.briar.android.account.NewOrRecoverActivity">
+			<meta-data
+				android:name="android.support.PARENT_ACTIVITY"
+				android:value="org.briarproject.briar.android.account.NewOrRecoverActivity" />
+		</activity>
+
+		<activity
+			android:name="org.briarproject.briar.android.socialbackup.CustodianHelpRecoverActivity"
+			android:label="@string/activity_name_custodian_help_recovery"
+			android:parentActivityName="org.briarproject.briar.android.conversation.ConversationActivity">
+			<meta-data
+				android:name="android.support.PARENT_ACTIVITY"
+				android:value="org.briarproject.briar.android.conversation.ConversationActivity" />
+		</activity>
+
 		<activity
 			android:name="org.briarproject.briar.android.conversation.ConversationActivity"
 			android:label="@string/app_name"

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

@@ -13,6 +13,7 @@ import org.briarproject.bramble.api.contact.ContactExchangeManager;
 import org.briarproject.bramble.api.contact.ContactManager;
 import org.briarproject.bramble.api.crypto.CryptoExecutor;
 import org.briarproject.bramble.api.crypto.PasswordStrengthEstimator;
+import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.TransactionManager;
 import org.briarproject.bramble.api.event.EventBus;
@@ -34,6 +35,7 @@ import org.briarproject.briar.BriarCoreModule;
 import org.briarproject.briar.android.attachment.AttachmentModule;
 import org.briarproject.briar.android.attachment.media.MediaModule;
 import org.briarproject.briar.android.conversation.glide.BriarModelLoader;
+import org.briarproject.briar.android.logging.CachingLogHandler;
 import org.briarproject.briar.android.login.SignInReminderReceiver;
 import org.briarproject.briar.android.view.EmojiTextInputView;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
@@ -58,7 +60,9 @@ import org.briarproject.briar.api.privategroup.PrivateGroupFactory;
 import org.briarproject.briar.api.privategroup.PrivateGroupManager;
 import org.briarproject.briar.api.privategroup.invitation.GroupInvitationFactory;
 import org.briarproject.briar.api.privategroup.invitation.GroupInvitationManager;
+import org.briarproject.briar.api.socialbackup.SocialBackupManager;
 import org.briarproject.briar.api.test.TestDataCreator;
+import org.briarproject.briar.socialbackup.SocialBackupManagerImpl_Factory;
 
 import java.util.concurrent.Executor;
 
@@ -179,6 +183,14 @@ public interface AndroidComponent
 
 	AndroidWakeLockManager wakeLockManager();
 
+	CachingLogHandler logHandler();
+
+	Thread.UncaughtExceptionHandler exceptionHandler();
+
+	SocialBackupManager socialBackupManager();
+
+    DatabaseComponent databaseComponent();
+
 	void inject(SignInReminderReceiver briarService);
 
 	void inject(BriarService briarService);

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

@@ -255,7 +255,7 @@ class AndroidNotificationManagerImpl implements AndroidNotificationManager,
 				R.string.ongoing_notification_title;
 		int text = locked ? R.string.lock_tap_to_unlock :
 				R.string.ongoing_notification_text;
-		int icon = locked ? R.drawable.startup_lock :
+		int icon = locked ? R.drawable.notification_lock :
 				R.drawable.notification_ongoing;
 		// Ongoing foreground notification that shows BriarService is running
 		NotificationCompat.Builder b =
@@ -624,7 +624,7 @@ class AndroidNotificationManagerImpl implements AndroidNotificationManager,
 
 		NotificationCompat.Builder b =
 				new NotificationCompat.Builder(appContext, REMINDER_CHANNEL_ID);
-		b.setSmallIcon(R.drawable.ic_signout);
+		b.setSmallIcon(R.drawable.notification_signout);
 		b.setColor(getColor(appContext, R.color.briar_primary));
 		b.setContentTitle(
 				appContext.getText(R.string.reminder_notification_title));

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

@@ -33,12 +33,13 @@ import org.briarproject.briar.android.account.SetupModule;
 import org.briarproject.briar.android.contact.ContactListModule;
 import org.briarproject.briar.android.forum.ForumModule;
 import org.briarproject.briar.android.keyagreement.ContactExchangeModule;
+import org.briarproject.briar.android.logging.LoggingModule;
 import org.briarproject.briar.android.login.LoginModule;
 import org.briarproject.briar.android.navdrawer.NavDrawerModule;
 import org.briarproject.briar.android.privategroup.conversation.GroupConversationModule;
-import org.briarproject.briar.android.settings.SettingsModule;
 import org.briarproject.briar.android.privategroup.list.GroupListModule;
 import org.briarproject.briar.android.reporting.DevReportModule;
+import org.briarproject.briar.android.settings.SettingsModule;
 import org.briarproject.briar.android.sharing.SharingModule;
 import org.briarproject.briar.android.test.TestAvatarCreatorImpl;
 import org.briarproject.briar.android.viewmodel.ViewModelModule;
@@ -47,6 +48,7 @@ import org.briarproject.briar.api.android.DozeWatchdog;
 import org.briarproject.briar.api.android.LockManager;
 import org.briarproject.briar.api.android.ScreenFilterMonitor;
 import org.briarproject.briar.api.test.TestAvatarCreator;
+import org.briarproject.briar.socialbackup.AndroidDarkCrystalModule;
 
 import java.io.File;
 import java.security.GeneralSecurityException;
@@ -74,12 +76,14 @@ import static org.briarproject.briar.android.TestingConstants.IS_DEBUG_BUILD;
 		SetupModule.class,
 		DozeHelperModule.class,
 		ContactExchangeModule.class,
+		LoggingModule.class,
 		LoginModule.class,
 		NavDrawerModule.class,
 		ViewModelModule.class,
 		SettingsModule.class,
 		DevReportModule.class,
 		ContactListModule.class,
+		AndroidDarkCrystalModule.class,
 		// below need to be within same scope as ViewModelProvider.Factory
 		ForumModule.class,
 		GroupListModule.class,
@@ -192,6 +196,11 @@ public class AppModule {
 			public File getReportDir() {
 				return AndroidUtils.getReportDir(app.getApplicationContext());
 			}
+
+			@Override
+			public File getLogcatFile() {
+				return AndroidUtils.getLogcatFile(app.getApplicationContext());
+			}
 		};
 		return devConfig;
 	}

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

@@ -6,9 +6,6 @@ import android.content.SharedPreferences;
 import org.briarproject.bramble.BrambleApplication;
 import org.briarproject.briar.android.navdrawer.NavDrawerActivity;
 
-import java.util.Collection;
-import java.util.logging.LogRecord;
-
 /**
  * This exists so that the Application object will not necessarily be cast
  * directly to the Briar application object.
@@ -17,8 +14,6 @@ public interface BriarApplication extends BrambleApplication {
 
 	Class<? extends Activity> ENTRY_ACTIVITY = NavDrawerActivity.class;
 
-	Collection<LogRecord> getRecentLogRecords();
-
 	AndroidComponent getApplicationComponent();
 
 	SharedPreferences getDefaultSharedPreferences();

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

@@ -20,12 +20,10 @@ import org.briarproject.bramble.BrambleCoreEagerSingletons;
 import org.briarproject.briar.BriarCoreEagerSingletons;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.logging.CachingLogHandler;
-import org.briarproject.briar.android.reporting.BriarExceptionHandler;
 import org.briarproject.briar.android.util.UiUtils;
 
-import java.util.Collection;
+import java.lang.Thread.UncaughtExceptionHandler;
 import java.util.logging.Handler;
-import java.util.logging.LogRecord;
 import java.util.logging.Logger;
 
 import androidx.annotation.NonNull;
@@ -42,22 +40,18 @@ public class BriarApplicationImpl extends Application
 	private static final Logger LOG =
 			getLogger(BriarApplicationImpl.class.getName());
 
-	private final CachingLogHandler logHandler = new CachingLogHandler();
-	private final BriarExceptionHandler exceptionHandler =
-			new BriarExceptionHandler(this);
-
 	private AndroidComponent applicationComponent;
 	private volatile SharedPreferences prefs;
 
 	@Override
 	protected void attachBaseContext(Context base) {
-		Thread.setDefaultUncaughtExceptionHandler(exceptionHandler);
 		if (prefs == null)
 			prefs = PreferenceManager.getDefaultSharedPreferences(base);
 		// Loading the language needs to be done here.
 		Localizer.initialize(prefs);
 		super.attachBaseContext(
 				Localizer.getInstance().setLocale(base));
+		Localizer.getInstance().setLocale(this);
 		setTheme(base, prefs);
 	}
 
@@ -67,6 +61,11 @@ public class BriarApplicationImpl extends Application
 
 		if (IS_DEBUG_BUILD) enableStrictMode();
 
+		applicationComponent = createApplicationComponent();
+		UncaughtExceptionHandler exceptionHandler =
+				applicationComponent.exceptionHandler();
+		Thread.setDefaultUncaughtExceptionHandler(exceptionHandler);
+
 		Logger rootLogger = getLogger("");
 		Handler[] handlers = rootLogger.getHandlers();
 		// Disable the Android logger for release builds
@@ -78,12 +77,12 @@ public class BriarApplicationImpl extends Application
 			// Restore the default handlers after the level raising handler
 			for (Handler handler : handlers) rootLogger.addHandler(handler);
 		}
+		CachingLogHandler logHandler = applicationComponent.logHandler();
 		rootLogger.addHandler(logHandler);
 		rootLogger.setLevel(IS_DEBUG_BUILD ? FINE : INFO);
 
 		LOG.info("Created");
 
-		applicationComponent = createApplicationComponent();
 		EmojiManager.install(new GoogleEmojiProvider());
 	}
 
@@ -136,11 +135,6 @@ public class BriarApplicationImpl extends Application
 		return applicationComponent;
 	}
 
-	@Override
-	public Collection<LogRecord> getRecentLogRecords() {
-		return logHandler.getRecentLogRecords();
-	}
-
 	@Override
 	public AndroidComponent getApplicationComponent() {
 		return applicationComponent;

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

@@ -37,7 +37,7 @@ import javax.inject.Inject;
 import androidx.core.app.NotificationCompat;
 
 import static android.app.NotificationManager.IMPORTANCE_DEFAULT;
-import static android.app.NotificationManager.IMPORTANCE_NONE;
+import static android.app.NotificationManager.IMPORTANCE_LOW;
 import static android.app.PendingIntent.FLAG_UPDATE_CURRENT;
 import static android.content.Intent.ACTION_SHUTDOWN;
 import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TASK;
@@ -46,6 +46,7 @@ import static android.content.Intent.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS;
 import static android.content.Intent.FLAG_ACTIVITY_NEW_TASK;
 import static android.content.Intent.FLAG_ACTIVITY_NO_ANIMATION;
 import static android.os.Build.VERSION.SDK_INT;
+import static android.os.Process.myPid;
 import static androidx.core.app.NotificationCompat.VISIBILITY_SECRET;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
@@ -56,8 +57,10 @@ import static org.briarproject.briar.android.BriarApplication.ENTRY_ACTIVITY;
 import static org.briarproject.briar.api.android.AndroidNotificationManager.FAILURE_CHANNEL_ID;
 import static org.briarproject.briar.api.android.AndroidNotificationManager.FAILURE_NOTIFICATION_ID;
 import static org.briarproject.briar.api.android.AndroidNotificationManager.ONGOING_CHANNEL_ID;
+import static org.briarproject.briar.api.android.AndroidNotificationManager.ONGOING_CHANNEL_OLD_ID;
 import static org.briarproject.briar.api.android.AndroidNotificationManager.ONGOING_NOTIFICATION_ID;
 import static org.briarproject.briar.api.android.LockManager.ACTION_LOCK;
+import static org.briarproject.briar.api.android.LockManager.EXTRA_PID;
 
 public class BriarService extends Service {
 
@@ -120,11 +123,17 @@ public class BriarService extends Service {
 			if (SDK_INT >= 26) {
 				NotificationManager nm = (NotificationManager)
 						requireNonNull(getSystemService(NOTIFICATION_SERVICE));
+				// Delete the old notification channel, which had
+				// IMPORTANCE_NONE and showed a badge
+				nm.deleteNotificationChannel(ONGOING_CHANNEL_OLD_ID);
+				// Use IMPORTANCE_LOW so the system doesn't show its own
+				// notification on API 26-27
 				NotificationChannel ongoingChannel = new NotificationChannel(
 						ONGOING_CHANNEL_ID,
 						getString(R.string.ongoing_notification_title),
-						IMPORTANCE_NONE);
+						IMPORTANCE_LOW);
 				ongoingChannel.setLockscreenVisibility(VISIBILITY_SECRET);
+				ongoingChannel.setShowBadge(false);
 				nm.createNotificationChannel(ongoingChannel);
 				NotificationChannel failureChannel = new NotificationChannel(
 						FAILURE_CHANNEL_ID,
@@ -170,6 +179,7 @@ public class BriarService extends Service {
 	@Override
 	protected void attachBaseContext(Context base) {
 		super.attachBaseContext(Localizer.getInstance().setLocale(base));
+		Localizer.getInstance().setLocale(this);
 	}
 
 	private void showStartupFailureNotification(StartResult result) {
@@ -202,7 +212,12 @@ public class BriarService extends Service {
 	@Override
 	public int onStartCommand(Intent intent, int flags, int startId) {
 		if (ACTION_LOCK.equals(intent.getAction())) {
-			lockManager.setLocked(true);
+			int pid = intent.getIntExtra(EXTRA_PID, -1);
+			if (pid == myPid()) lockManager.setLocked(true);
+			else if (LOG.isLoggable(WARNING)) {
+				LOG.warning("Tried to lock process " + pid + " but this is " +
+						myPid());
+			}
 		}
 		return START_NOT_STICKY; // Don't restart automatically if killed
 	}

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

@@ -68,7 +68,21 @@ public class Localizer {
 			return new Locale(tag);
 	}
 
-	// Returns the localized version of context
+	/*
+	 * Apply localization to the specified context.
+	 *
+	 * It updates the configuration of the context's resources object but can
+	 * also return a new context derived from the context parameter. Hence
+	 * make sure to work with the return value of this method instead of
+	 * the context you passed as a parameter.
+	 *
+	 * This method also has side-effects as it calls Locale#setDefault().
+	 *
+	 * When using this in attachBaseContext() of Application, Service or
+	 * Activity subclasses, it is important to not only apply this method to the
+	 * base Context parameter received in that method, but also apply it on the
+	 * class itself which also extends Context.
+	 */
 	public Context setLocale(Context context) {
 		Resources res = context.getResources();
 		Configuration conf = res.getConfiguration();
@@ -82,7 +96,7 @@ public class Localizer {
 		Locale.setDefault(locale);
 		if (SDK_INT >= 17) {
 			conf.setLocale(locale);
-			context.createConfigurationContext(conf);
+			context = context.createConfigurationContext(conf);
 		} else
 			conf.locale = locale;
 		//noinspection deprecation

briar-android/src/main/java/org/briarproject/briar/android/account/LockManagerImpl.java

@@ -32,8 +32,10 @@ import androidx.lifecycle.LiveData;
 import androidx.lifecycle.MutableLiveData;
 
 import static android.app.AlarmManager.ELAPSED_REALTIME;
+import static android.app.PendingIntent.FLAG_UPDATE_CURRENT;
 import static android.app.PendingIntent.getService;
 import static android.content.Context.ALARM_SERVICE;
+import static android.os.Process.myPid;
 import static android.os.SystemClock.elapsedRealtime;
 import static java.util.concurrent.TimeUnit.MINUTES;
 import static java.util.logging.Level.WARNING;
@@ -75,23 +77,25 @@ public class LockManagerImpl implements LockManager, Service, EventListener {
 	LockManagerImpl(Application app, SettingsManager settingsManager,
 			AndroidNotificationManager notificationManager,
 			@DatabaseExecutor Executor dbExecutor) {
-		this.appContext = app.getApplicationContext();
+		appContext = app.getApplicationContext();
 		this.settingsManager = settingsManager;
 		this.notificationManager = notificationManager;
 		this.dbExecutor = dbExecutor;
-		this.alarmManager =
+		alarmManager =
 				(AlarmManager) appContext.getSystemService(ALARM_SERVICE);
 		Intent i =
 				new Intent(ACTION_LOCK, null, appContext, BriarService.class);
-		this.lockIntent = getService(appContext, 0, i, 0);
-		this.timeoutNever = Integer.valueOf(
+		i.putExtra(EXTRA_PID, myPid());
+		// When not using FLAG_UPDATE_CURRENT, the intent might have no extras
+		lockIntent = getService(appContext, 0, i, FLAG_UPDATE_CURRENT);
+		timeoutNever = Integer.parseInt(
 				appContext.getString(R.string.pref_lock_timeout_value_never));
-		this.timeoutDefault = Integer.valueOf(
+		timeoutDefault = Integer.parseInt(
 				appContext.getString(R.string.pref_lock_timeout_value_default));
-		this.timeoutMinutes = timeoutNever;
+		timeoutMinutes = timeoutNever;
 
 		// setting this in the constructor makes #getValue() @NonNull
-		this.lockable.setValue(false);
+		lockable.setValue(false);
 	}
 
 	@Override
@@ -148,7 +152,7 @@ public class LockManagerImpl implements LockManager, Service, EventListener {
 		boolean oldValue = lockable.getValue();
 		boolean newValue = hasScreenLock(appContext) && lockableSetting;
 		if (oldValue != newValue) {
-			this.lockable.setValue(newValue);
+			lockable.setValue(newValue);
 		}
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/account/NewOrRecoverActivity.java

@@ -0,0 +1,59 @@
+package org.briarproject.briar.android.account;
+
+import android.content.Intent;
+import android.os.Bundle;
+
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.activity.BaseActivity;
+import org.briarproject.briar.android.fragment.BaseFragment;
+import org.briarproject.briar.android.socialbackup.RecoverActivity;
+
+import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TASK;
+import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
+import static android.content.Intent.FLAG_ACTIVITY_NEW_TASK;
+import static android.content.Intent.FLAG_ACTIVITY_TASK_ON_HOME;
+
+public class NewOrRecoverActivity extends BaseActivity implements
+		BaseFragment.BaseFragmentListener, SetupNewAccountChosenListener,
+		RecoverAccountListener {
+
+	@Override
+	public void injectActivity(ActivityComponent component) {
+		component.inject(this);
+	}
+
+	@Override
+	public void onCreate(Bundle state) {
+		super.onCreate(state);
+		// fade-in after splash screen instead of default animation
+		overridePendingTransition(R.anim.fade_in, R.anim.fade_out);
+		setContentView(R.layout.activity_fragment_container);
+		NewOrRecoverFragment fragment = NewOrRecoverFragment.newInstance();
+		showInitialFragment(fragment);
+	}
+
+	@Override
+	public void setupNewAccountChosen() {
+		finish();
+		Intent i = new Intent(this, SetupActivity.class);
+		i.addFlags(FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_CLEAR_TOP |
+				FLAG_ACTIVITY_CLEAR_TASK | FLAG_ACTIVITY_TASK_ON_HOME);
+		startActivity(i);
+	}
+
+	@Override
+	public void recoverAccountChosen() {
+		finish();
+		Intent i = new Intent(this, RecoverActivity.class);
+		i.addFlags(FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_CLEAR_TOP |
+				FLAG_ACTIVITY_CLEAR_TASK | FLAG_ACTIVITY_TASK_ON_HOME);
+		startActivity(i);
+	}
+
+	@Override
+	@Deprecated
+	public void runOnDbThread(Runnable runnable) {
+		throw new RuntimeException("Don't use this deprecated method here.");
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/account/NewOrRecoverFragment.java

@@ -0,0 +1,70 @@
+package org.briarproject.briar.android.account;
+
+import android.content.Context;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Button;
+
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.fragment.BaseFragment;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+public class NewOrRecoverFragment extends BaseFragment {
+
+	public static final String TAG = NewOrRecoverFragment.class.getName();
+
+	protected SetupNewAccountChosenListener setupNewAccountListener;
+	protected RecoverAccountListener recoverAccountListener;
+
+	public static NewOrRecoverFragment newInstance() {
+		Bundle bundle = new Bundle();
+		NewOrRecoverFragment fragment = new NewOrRecoverFragment();
+		fragment.setArguments(bundle);
+		return fragment;
+	}
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		requireActivity().setTitle(R.string.setup_title);
+	}
+
+	@Nullable
+	@Override
+	public View onCreateView(@NonNull LayoutInflater inflater, @Nullable
+			ViewGroup container, @Nullable Bundle savedInstanceState) {
+		View view = inflater.inflate(R.layout.fragment_new_or_recover,
+				container, false);
+		Button newAccountButton = view.findViewById(R.id.buttonSetupNewAccount);
+		newAccountButton.setOnClickListener(e -> {
+			setupNewAccountListener.setupNewAccountChosen();
+		});
+
+		Button recoverAccountButton = view.findViewById(R.id.buttonRestoreAccount);
+		recoverAccountButton.setOnClickListener(e -> {
+			recoverAccountListener.recoverAccountChosen();
+		});
+		return view;
+	}
+
+	@Override
+	public void onAttach(Context context) {
+		super.onAttach(context);
+		setupNewAccountListener = (SetupNewAccountChosenListener) context;
+		recoverAccountListener = (RecoverAccountListener) context;
+	}
+
+	@Override
+	public String getUniqueTag() {
+		return TAG;
+	}
+
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/account/RecoverAccountListener.java

@@ -0,0 +1,8 @@
+package org.briarproject.briar.android.account;
+
+import androidx.annotation.UiThread;
+
+public interface RecoverAccountListener {
+	@UiThread
+	void recoverAccountChosen();
+}

briar-android/src/main/java/org/briarproject/briar/android/account/SetupNewAccountChosenListener.java

@@ -0,0 +1,8 @@
+package org.briarproject.briar.android.account;
+
+import androidx.annotation.UiThread;
+
+public interface SetupNewAccountChosenListener {
+	@UiThread
+	void setupNewAccountChosen();
+}

briar-android/src/main/java/org/briarproject/briar/android/account/UnlockActivity.java

@@ -77,7 +77,7 @@ public class UnlockActivity extends BaseActivity {
 
 	@Override
 	protected void onActivityResult(int requestCode, int resultCode,
-			Intent data) {
+			@Nullable Intent data) {
 		super.onActivityResult(requestCode, resultCode, data);
 		if (requestCode == REQUEST_KEYGUARD_UNLOCK) {
 			if (resultCode == RESULT_OK) unlock();

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

@@ -2,10 +2,13 @@ package org.briarproject.briar.android.activity;
 
 import android.app.Activity;
 
+import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.briar.android.AndroidComponent;
 import org.briarproject.briar.android.StartupFailureActivity;
 import org.briarproject.briar.android.account.AuthorNameFragment;
 import org.briarproject.briar.android.account.DozeFragment;
+import org.briarproject.briar.android.account.NewOrRecoverActivity;
+import org.briarproject.briar.android.account.NewOrRecoverFragment;
 import org.briarproject.briar.android.account.SetPasswordFragment;
 import org.briarproject.briar.android.account.SetupActivity;
 import org.briarproject.briar.android.account.UnlockActivity;
@@ -77,20 +80,32 @@ import org.briarproject.briar.android.sharing.ShareBlogFragment;
 import org.briarproject.briar.android.sharing.ShareForumActivity;
 import org.briarproject.briar.android.sharing.ShareForumFragment;
 import org.briarproject.briar.android.sharing.SharingModule;
+//import org.briarproject.briar.android.socialbackup.CustodianDisplayFragment;
+import org.briarproject.briar.android.socialbackup.CustodianHelpRecoverActivity;
+import org.briarproject.briar.android.socialbackup.CustodianSelectorFragment;
+import org.briarproject.briar.android.socialbackup.DistributedBackupActivity;
+import org.briarproject.briar.android.socialbackup.ExistingBackupFragment;
+import org.briarproject.briar.android.socialbackup.OwnerRecoveryModeExplainerFragment;
+import org.briarproject.briar.android.socialbackup.RecoverActivity;
+import org.briarproject.briar.android.socialbackup.ShardQrCodeFragment;
+import org.briarproject.briar.android.socialbackup.ShardsSentFragment;
+import org.briarproject.briar.android.socialbackup.ThresholdSelectorFragment;
+import org.briarproject.briar.android.socialbackup.creation.CreateBackupModule;
 import org.briarproject.briar.android.splash.SplashScreenActivity;
 import org.briarproject.briar.android.test.TestDataActivity;
 
 import dagger.Component;
 
 @ActivityScope
-@Component(modules = {
+@Component(modules ={
 		ActivityModule.class,
 		BlogModule.class,
 		CreateGroupModule.class,
 		GroupInvitationModule.class,
 		GroupMemberModule.class,
 		GroupRevealModule.class,
-		SharingModule.SharingLegacyModule.class
+		SharingModule.SharingLegacyModule.class,
+		CreateBackupModule.class
 }, dependencies = AndroidComponent.class)
 public interface ActivityComponent {
 
@@ -182,6 +197,10 @@ public interface ActivityComponent {
 
 	void inject(CrashReportActivity crashReportActivity);
 
+	void inject(NewOrRecoverActivity newOrRecoverActivity);
+
+	void inject(CustodianHelpRecoverActivity custodianHelpRecoverActivity);
+
 	// Fragments
 
 	void inject(AuthorNameFragment fragment);
@@ -238,4 +257,23 @@ public interface ActivityComponent {
 
 	void inject(ConfirmAvatarDialogFragment fragment);
 
+	void inject(ThresholdSelectorFragment thresholdSelectorFragment);
+
+	void inject(ShardQrCodeFragment shardQrCodeFragment);
+
+	void inject(DistributedBackupActivity distributedBackupActivity);
+
+	void inject(RecoverActivity recoverActivity);
+
+	void inject(DatabaseComponent databaseComponent);
+
+	void inject(CustodianSelectorFragment custodianSelectorFragment);
+
+	void inject(ShardsSentFragment shardsSentFragment);
+
+	void inject(OwnerRecoveryModeExplainerFragment ownerRecoveryModeExplainerFragment);
+
+	void inject(ExistingBackupFragment existingBackupFragment);
+
+	void inject(NewOrRecoverFragment newOrRecoverFragment);
 }

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

@@ -109,6 +109,7 @@ public abstract class BaseActivity extends AppCompatActivity
 	protected void attachBaseContext(Context base) {
 		super.attachBaseContext(
 				Localizer.getInstance().setLocale(base));
+		Localizer.getInstance().setLocale(this);
 	}
 
 	public ActivityComponent getActivityComponent() {

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

@@ -124,7 +124,7 @@ public class AddContactViewModel extends DbViewModel {
 		return addContactResult;
 	}
 
-	public void updatePendingContact(String name, PendingContact p) {
+	void updatePendingContact(String name, PendingContact p) {
 		runOnDbThread(() -> {
 			try {
 				contactManager.removePendingContact(p.getId());

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

@@ -29,11 +29,11 @@ import org.briarproject.briar.android.fragment.BaseFragment;
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.StringRes;
 import androidx.appcompat.app.AlertDialog.Builder;
 import androidx.lifecycle.LifecycleOwner;
 import androidx.lifecycle.ViewModelProvider;
-import androidx.lifecycle.ViewModelProviders;
 
 import static android.view.View.INVISIBLE;
 import static android.view.View.VISIBLE;
@@ -48,6 +48,7 @@ import static org.briarproject.briar.android.util.UiUtils.getDialogIcon;
 public class NicknameFragment extends BaseFragment {
 
 	private static final String TAG = NicknameFragment.class.getName();
+	private static final String SAVED_LINK = "savedLink";
 
 	@Inject
 	ViewModelProvider.Factory viewModelFactory;
@@ -67,6 +68,20 @@ public class NicknameFragment extends BaseFragment {
 	@Override
 	public void injectFragment(ActivityComponent component) {
 		component.inject(this);
+		viewModel = new ViewModelProvider(requireActivity(), viewModelFactory)
+				.get(AddContactViewModel.class);
+	}
+
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		if (savedInstanceState != null) {
+			// When the activity (and the ViewModel) get destroyed,
+			// the link will not be available anymore and needs to be restored.
+			// TODO migrate to SavedStateViewModelFactory (once we can use it)
+			String savedLink = savedInstanceState.getString(SAVED_LINK);
+			if (savedLink != null) viewModel.setRemoteHandshakeLink(savedLink);
+		}
 	}
 
 	@Nullable
@@ -74,14 +89,9 @@ public class NicknameFragment extends BaseFragment {
 	public View onCreateView(LayoutInflater inflater,
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
-		if (getActivity() == null || getContext() == null) return null;
-
 		View v = inflater.inflate(R.layout.fragment_nickname,
 				container, false);
 
-		viewModel = ViewModelProviders.of(getActivity(), viewModelFactory)
-				.get(AddContactViewModel.class);
-
 		contactNameLayout = v.findViewById(R.id.contactNameLayout);
 		contactNameInput = v.findViewById(R.id.contactNameInput);
 
@@ -93,6 +103,12 @@ public class NicknameFragment extends BaseFragment {
 		return v;
 	}
 
+	@Override
+	public void onSaveInstanceState(@NonNull Bundle outState) {
+		super.onSaveInstanceState(outState);
+		outState.putString(SAVED_LINK, viewModel.getRemoteHandshakeLink());
+	}
+
 	@Nullable
 	private String getNicknameOrNull() {
 		Editable text = contactNameInput.getText();

briar-android/src/main/java/org/briarproject/briar/android/contactselection/BaseContactSelectorFragment.java

@@ -56,8 +56,11 @@ public abstract class BaseContactSelectorFragment<I extends SelectableContactIte
 
 		Bundle args = requireArguments();
 		byte[] b = args.getByteArray(GROUP_ID);
-		if (b == null) throw new IllegalStateException("No GroupId");
-		groupId = new GroupId(b);
+//		if (b == null) throw new IllegalStateException("No GroupId");
+		// TODO find what the groupId should be when selecting custodians
+		if (b != null) {
+			groupId = new GroupId(b);
+		}
 	}
 
 	@Override

briar-android/src/main/java/org/briarproject/briar/android/contactselection/ContactSelectorFragment.java

@@ -18,7 +18,7 @@ public abstract class ContactSelectorFragment extends
 
 	public static final String TAG = ContactSelectorFragment.class.getName();
 
-	private Menu menu;
+	protected Menu menu;
 
 	@Override
 	protected ContactSelectorAdapter getAdapter(Context context,

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

@@ -3,6 +3,7 @@ package org.briarproject.briar.android.conversation;
 import android.annotation.SuppressLint;
 import android.content.DialogInterface;
 import android.content.Intent;
+import android.graphics.drawable.Drawable;
 import android.os.Bundle;
 import android.os.Parcelable;
 import android.transition.Slide;
@@ -51,6 +52,7 @@ import org.briarproject.briar.android.conversation.ConversationVisitor.TextCache
 import org.briarproject.briar.android.forum.ForumActivity;
 import org.briarproject.briar.android.introduction.IntroductionActivity;
 import org.briarproject.briar.android.privategroup.conversation.GroupActivity;
+import org.briarproject.briar.android.socialbackup.CustodianHelpRecoverActivity;
 import org.briarproject.briar.android.util.BriarSnackbarBuilder;
 import org.briarproject.briar.android.view.BriarRecyclerView;
 import org.briarproject.briar.android.view.ImagePreview;
@@ -105,6 +107,7 @@ import androidx.recyclerview.selection.SelectionTracker.SelectionObserver;
 import androidx.recyclerview.selection.StorageStrategy;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
+import androidx.vectordrawable.graphics.drawable.VectorDrawableCompat;
 import de.hdodenhof.circleimageview.CircleImageView;
 import uk.co.samuelwall.materialtaptargetprompt.MaterialTapTargetPrompt;
 
@@ -394,6 +397,12 @@ public class ConversationActivity extends BriarActivity
 			case R.id.action_social_remove_person:
 				askToRemoveContact();
 				return true;
+			case R.id.action_help_recover_account:
+				if (contactId == null) return false;
+				Intent i = new Intent(this, CustodianHelpRecoverActivity.class);
+				i.putExtra(CONTACT_ID, contactId.getInt());
+				startActivity(i);
+				return true;
 			default:
 				return super.onOptionsItemSelected(item);
 		}
@@ -479,12 +488,10 @@ public class ConversationActivity extends BriarActivity
 	@UiThread
 	private void displayContactOnlineStatus() {
 		if (connectionRegistry.isConnected(contactId)) {
-			toolbarStatus.setImageDrawable(ContextCompat.getDrawable(
-					ConversationActivity.this, R.drawable.contact_online));
+			toolbarStatus.setImageResource(R.drawable.contact_online);
 			toolbarStatus.setContentDescription(getString(R.string.online));
 		} else {
-			toolbarStatus.setImageDrawable(ContextCompat.getDrawable(
-					ConversationActivity.this, R.drawable.contact_offline));
+			toolbarStatus.setImageResource(R.drawable.contact_offline);
 			toolbarStatus.setContentDescription(getString(R.string.offline));
 		}
 	}
@@ -935,13 +942,16 @@ public class ConversationActivity extends BriarActivity
 			return;
 		}
 
+		int color =
+				ContextCompat.getColor(this, R.color.briar_primary);
+		Drawable drawable = VectorDrawableCompat
+				.create(getResources(), R.drawable.ic_more_vert_accent, null);
 		new MaterialTapTargetPrompt.Builder(ConversationActivity.this,
 				R.style.OnboardingDialogTheme).setTarget(target)
 				.setPrimaryText(R.string.introduction_onboarding_title)
 				.setSecondaryText(R.string.introduction_onboarding_text)
-				.setIcon(R.drawable.ic_more_vert_accent)
-				.setBackgroundColour(
-						ContextCompat.getColor(this, R.color.briar_primary))
+				.setIconDrawable(drawable)
+				.setBackgroundColour(color)
 				.show();
 	}
 

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

@@ -3,6 +3,7 @@ package org.briarproject.briar.android.conversation;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.api.conversation.ConversationRequest;
 import org.briarproject.briar.api.conversation.ConversationResponse;
+import org.briarproject.briar.api.socialbackup.ShardMessageHeader;
 
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.NotThreadSafe;
@@ -30,6 +31,13 @@ class ConversationNoticeItem extends ConversationItem {
 		this.msgText = null;
 	}
 
+	ConversationNoticeItem(@LayoutRes int layoutRes, String text,
+			ShardMessageHeader r) {
+		super(layoutRes, r);
+		this.text = text;
+		this.msgText = null;
+	}
+
 	@Nullable
 	String getMsgText() {
 		return msgText;

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

@@ -16,6 +16,7 @@ import org.briarproject.briar.api.introduction.IntroductionResponse;
 import org.briarproject.briar.api.messaging.PrivateMessageHeader;
 import org.briarproject.briar.api.privategroup.invitation.GroupInvitationRequest;
 import org.briarproject.briar.api.privategroup.invitation.GroupInvitationResponse;
+import org.briarproject.briar.api.socialbackup.ShardMessageHeader;
 
 import java.util.List;
 
@@ -292,6 +293,19 @@ class ConversationVisitor implements
 		}
 	}
 
+	@Override
+	public ConversationItem visitShardMessage(ShardMessageHeader r) {
+		if (r.isLocal()) {
+			String text = ctx.getString(R.string.social_backup_shard_sent);
+			return new ConversationNoticeItem(
+					R.layout.list_item_conversation_notice_out, text, r);
+		} else {
+			String text = ctx.getString(R.string.social_backup_shard_received);
+			return new ConversationNoticeItem(
+					R.layout.list_item_conversation_notice_in, text, r);
+		}
+	}
+
 	interface TextCache {
 		@Nullable
 		String getText(MessageId m);

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

@@ -79,12 +79,6 @@ public class ForumActivity extends
 		}
 	}
 
-	@Override
-	public void onStart() {
-		super.onStart();
-		viewModel.clearForumPostNotification();
-	}
-
 	@Override
 	protected void onActivityResult(int request, int result,
 			@Nullable Intent data) {
@@ -109,16 +103,16 @@ public class ForumActivity extends
 		// Handle presses on the action bar items
 		int itemId = item.getItemId();
 		if (itemId == R.id.action_forum_share) {
-			Intent i2 = new Intent(this, ShareForumActivity.class);
-			i2.setFlags(FLAG_ACTIVITY_CLEAR_TOP);
-			i2.putExtra(GROUP_ID, groupId.getBytes());
-			startActivityForResult(i2, REQUEST_SHARE_FORUM);
+			Intent i = new Intent(this, ShareForumActivity.class);
+			i.setFlags(FLAG_ACTIVITY_CLEAR_TOP);
+			i.putExtra(GROUP_ID, groupId.getBytes());
+			startActivityForResult(i, REQUEST_SHARE_FORUM);
 			return true;
 		} else if (itemId == R.id.action_forum_sharing_status) {
-			Intent i3 = new Intent(this, ForumSharingStatusActivity.class);
-			i3.setFlags(FLAG_ACTIVITY_CLEAR_TOP);
-			i3.putExtra(GROUP_ID, groupId.getBytes());
-			startActivity(i3);
+			Intent i = new Intent(this, ForumSharingStatusActivity.class);
+			i.setFlags(FLAG_ACTIVITY_CLEAR_TOP);
+			i.putExtra(GROUP_ID, groupId.getBytes());
+			startActivity(i);
 			return true;
 		} else if (itemId == R.id.action_forum_delete) {
 			showUnsubscribeDialog();

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

@@ -26,7 +26,6 @@ import org.briarproject.briar.android.threaded.ThreadListViewModel;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
 import org.briarproject.briar.api.client.MessageTracker;
 import org.briarproject.briar.api.client.MessageTracker.GroupCount;
-import org.briarproject.briar.api.client.PostHeader;
 import org.briarproject.briar.api.forum.Forum;
 import org.briarproject.briar.api.forum.ForumInvitationResponse;
 import org.briarproject.briar.api.forum.ForumManager;
@@ -94,8 +93,9 @@ class ForumViewModel extends ThreadListViewModel<ForumPostItem> {
 			ForumPostReceivedEvent f = (ForumPostReceivedEvent) e;
 			if (f.getGroupId().equals(groupId)) {
 				LOG.info("Forum post received, adding...");
-				ForumPostItem item = buildItem(f.getHeader(), f.getText());
-				addItem(item);
+				ForumPostItem item =
+						new ForumPostItem(f.getHeader(), f.getText());
+				addItem(item, false);
 			}
 		} else if (e instanceof ForumInvitationResponseReceivedEvent) {
 			ForumInvitationResponseReceivedEvent f =
@@ -116,7 +116,7 @@ class ForumViewModel extends ThreadListViewModel<ForumPostItem> {
 		}
 	}
 
-	void clearForumPostNotification() {
+	protected void clearNotifications() {
 		notificationManager.clearForumPostNotification(groupId);
 	}
 
@@ -140,10 +140,22 @@ class ForumViewModel extends ThreadListViewModel<ForumPostItem> {
 			List<ForumPostHeader> headers =
 					forumManager.getPostHeaders(txn, groupId);
 			logDuration(LOG, "Loading headers", start);
-			return createItems(txn, headers, this::buildItem);
+			start = now();
+			List<ForumPostItem> items = new ArrayList<>();
+			for (ForumPostHeader header : headers) {
+				items.add(loadItem(txn, header));
+			}
+			logDuration(LOG, "Loading bodies and creating items", start);
+			return items;
 		}, this::setItems);
 	}
 
+	private ForumPostItem loadItem(Transaction txn, ForumPostHeader header)
+			throws DbException {
+		String text = forumManager.getPostText(txn, header.getId());
+		return new ForumPostItem(header, text);
+	}
+
 	@Override
 	public void createAndStoreMessage(String text,
 			@Nullable MessageId parentId) {
@@ -171,26 +183,15 @@ class ForumViewModel extends ThreadListViewModel<ForumPostItem> {
 	}
 
 	private void storePost(ForumPost msg, String text) {
-		runOnDbThread(() -> {
-			try {
-				long start = now();
-				ForumPostHeader header = forumManager.addLocalPost(msg);
-				addItemAsync(buildItem(header, text));
-				logDuration(LOG, "Storing forum post", start);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
-	}
-
-	private ForumPostItem buildItem(ForumPostHeader header, String text) {
-		return new ForumPostItem(header, text);
-	}
-
-	@Override
-	protected String loadMessageText(Transaction txn, PostHeader header)
-			throws DbException {
-		return forumManager.getPostText(txn, header.getId());
+		runOnDbThread(false, txn -> {
+			long start = now();
+			ForumPostHeader header = forumManager.addLocalPost(txn, msg);
+			logDuration(LOG, "Storing forum post", start);
+			txn.attach(() -> {
+				ForumPostItem item = new ForumPostItem(header, text);
+				addItem(item, true);
+			});
+		}, e -> logException(LOG, WARNING, e));
 	}
 
 	@Override
@@ -205,18 +206,13 @@ class ForumViewModel extends ThreadListViewModel<ForumPostItem> {
 	}
 
 	public void loadSharingContacts() {
-		runOnDbThread(() -> {
-			try {
-				Collection<Contact> contacts =
-						forumSharingManager.getSharedWith(groupId);
-				Collection<ContactId> contactIds =
-						new ArrayList<>(contacts.size());
-				for (Contact c : contacts) contactIds.add(c.getId());
-				sharingController.addAll(contactIds);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
+		runOnDbThread(true, txn -> {
+			Collection<Contact> contacts =
+					forumSharingManager.getSharedWith(txn, groupId);
+			Collection<ContactId> contactIds = new ArrayList<>(contacts.size());
+			for (Contact c : contacts) contactIds.add(c.getId());
+			txn.attach(() -> sharingController.addAll(contactIds));
+		}, e -> logException(LOG, WARNING, e));
 	}
 
 	void deleteForum() {

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

@@ -2,7 +2,7 @@ package org.briarproject.briar.android.keyagreement;
 
 import java.io.IOException;
 
-class CameraException extends IOException {
+public class CameraException extends IOException {
 
 	CameraException(String message) {
 		super(message);

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

@@ -30,7 +30,7 @@ import static java.util.logging.Level.WARNING;
 @SuppressWarnings("deprecation")
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-class QrCodeDecoder implements PreviewConsumer, PreviewCallback {
+public class QrCodeDecoder implements PreviewConsumer, PreviewCallback {
 
 	private static final Logger LOG =
 			Logger.getLogger(QrCodeDecoder.class.getName());
@@ -41,7 +41,7 @@ class QrCodeDecoder implements PreviewConsumer, PreviewCallback {
 	private Camera camera = null;
 	private int cameraIndex = 0;
 
-	QrCodeDecoder(ResultCallback callback) {
+	public QrCodeDecoder(ResultCallback callback) {
 		this.callback = callback;
 	}
 
@@ -142,7 +142,7 @@ class QrCodeDecoder implements PreviewConsumer, PreviewCallback {
 	}
 
 	@NotNullByDefault
-	interface ResultCallback {
+	public interface ResultCallback {
 
 		void handleResult(Result result);
 	}

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

@@ -21,13 +21,13 @@ import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.util.LogUtils.logException;
 
 @NotNullByDefault
-class QrCodeUtils {
+public class QrCodeUtils {
 
 	private static final Logger LOG =
 			Logger.getLogger(QrCodeUtils.class.getName());
 
 	@Nullable
-	static Bitmap createQrCode(DisplayMetrics dm, String input) {
+	public static Bitmap createQrCode(DisplayMetrics dm, String input) {
 		int smallestDimen = Math.min(dm.widthPixels, dm.heightPixels);
 		try {
 			// Generate QR code

briar-android/src/main/java/org/briarproject/briar/android/logging/BriefLogFormatter.java

@@ -4,6 +4,7 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.text.DateFormat;
 import java.text.SimpleDateFormat;
+import java.util.Collection;
 import java.util.Date;
 import java.util.TimeZone;
 import java.util.logging.Formatter;
@@ -17,6 +18,16 @@ import static java.util.Locale.US;
 @NotNullByDefault
 public class BriefLogFormatter extends Formatter {
 
+	public static String formatLog(Formatter formatter,
+			Collection<LogRecord> logRecords) {
+		StringBuilder sb = new StringBuilder();
+		for (LogRecord record : logRecords) {
+			String formatted = formatter.format(record);
+			sb.append(formatted).append('\n');
+		}
+		return sb.toString();
+	}
+
 	private final Object lock = new Object();
 	private final DateFormat dateFormat; // Locking: lock
 	private final Date date; // Locking: lock

briar-android/src/main/java/org/briarproject/briar/android/logging/CachingLogHandler.java

@@ -21,6 +21,10 @@ public class CachingLogHandler extends Handler {
 	// Locking: lock
 	private final Queue<LogRecord> recent = new LinkedList<>();
 
+	// package-private constructor
+	CachingLogHandler() {
+	}
+
 	@Override
 	public void publish(LogRecord record) {
 		synchronized (lock) {

briar-android/src/main/java/org/briarproject/briar/android/logging/LogDecrypter.java

@@ -0,0 +1,16 @@
+package org.briarproject.briar.android.logging;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.util.AndroidUtils;
+
+import androidx.annotation.Nullable;
+
+@NotNullByDefault
+public interface LogDecrypter {
+	/**
+	 * Returns decrypted log records from {@link AndroidUtils#getLogcatFile}
+	 * or null if there was an error reading the logs.
+	 */
+	@Nullable
+	String decryptLogs(@Nullable byte[] logKey);
+}

briar-android/src/main/java/org/briarproject/briar/android/logging/LogDecrypterImpl.java

@@ -0,0 +1,61 @@
+package org.briarproject.briar.android.logging;
+
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.reporting.DevConfig;
+import org.briarproject.bramble.api.transport.StreamReaderFactory;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Scanner;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import androidx.annotation.Nullable;
+
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+@NotNullByDefault
+class LogDecrypterImpl implements LogDecrypter {
+
+	private static final Logger LOG =
+			getLogger(LogDecrypterImpl.class.getName());
+
+	private final DevConfig devConfig;
+	private final StreamReaderFactory streamReaderFactory;
+
+	@Inject
+	LogDecrypterImpl(DevConfig devConfig,
+			StreamReaderFactory streamReaderFactory) {
+		this.devConfig = devConfig;
+		this.streamReaderFactory = streamReaderFactory;
+	}
+
+	@Nullable
+	@Override
+	public String decryptLogs(@Nullable byte[] logKey) {
+		if (logKey == null) return null;
+		SecretKey key = new SecretKey(logKey);
+		File logFile = devConfig.getLogcatFile();
+		try (InputStream in = new FileInputStream(logFile)) {
+			InputStream reader =
+					streamReaderFactory.createLogStreamReader(in, key);
+			Scanner s = new Scanner(reader);
+			StringBuilder sb = new StringBuilder();
+			while (s.hasNextLine()) sb.append(s.nextLine()).append("\n");
+			s.close();
+			return sb.toString();
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+			return null;
+		} finally {
+			//noinspection ResultOfMethodCallIgnored
+			logFile.delete();
+		}
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/logging/LogEncrypter.java

@@ -0,0 +1,16 @@
+package org.briarproject.briar.android.logging;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.util.AndroidUtils;
+
+import androidx.annotation.Nullable;
+
+@NotNullByDefault
+public interface LogEncrypter {
+	/**
+	 * Writes encrypted log records to {@link AndroidUtils#getLogcatFile}
+	 * and returns the encryption key if everything went fine.
+	 */
+	@Nullable
+	byte[] encryptLogs();
+}

briar-android/src/main/java/org/briarproject/briar/android/logging/LogEncrypterImpl.java

@@ -0,0 +1,77 @@
+package org.briarproject.briar.android.logging;
+
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.reporting.DevConfig;
+import org.briarproject.bramble.api.transport.StreamWriter;
+import org.briarproject.bramble.api.transport.StreamWriterFactory;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+import java.util.logging.Formatter;
+import java.util.logging.LogRecord;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import androidx.annotation.Nullable;
+
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+@NotNullByDefault
+class LogEncrypterImpl implements LogEncrypter {
+
+	private static final Logger LOG =
+			getLogger(LogEncrypterImpl.class.getName());
+
+	private final DevConfig devConfig;
+	private final CachingLogHandler logHandler;
+	private final CryptoComponent crypto;
+	private final StreamWriterFactory streamWriterFactory;
+
+	@Inject
+	LogEncrypterImpl(DevConfig devConfig,
+			CachingLogHandler logHandler,
+			CryptoComponent crypto,
+			StreamWriterFactory streamWriterFactory) {
+		this.devConfig = devConfig;
+		this.logHandler = logHandler;
+		this.crypto = crypto;
+		this.streamWriterFactory = streamWriterFactory;
+	}
+
+	@Nullable
+	@Override
+	public byte[] encryptLogs() {
+		SecretKey logKey = crypto.generateSecretKey();
+		File logFile = devConfig.getLogcatFile();
+		try (OutputStream out = new FileOutputStream(logFile)) {
+			StreamWriter streamWriter =
+					streamWriterFactory.createLogStreamWriter(out, logKey);
+			Writer writer =
+					new OutputStreamWriter(streamWriter.getOutputStream());
+			writeLogString(writer);
+			writer.close();
+			return logKey.getBytes();
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+			return null;
+		}
+	}
+
+	private void writeLogString(Writer writer) throws IOException {
+		Formatter formatter = new BriefLogFormatter();
+		for (LogRecord record : logHandler.getRecentLogRecords()) {
+			String formatted = formatter.format(record);
+			writer.append(formatted).append('\n');
+		}
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/logging/LoggingModule.java

@@ -0,0 +1,29 @@
+package org.briarproject.briar.android.logging;
+
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class LoggingModule {
+
+	@Provides
+	@Singleton
+	CachingLogHandler provideCachingLogHandler() {
+		return new CachingLogHandler();
+	}
+
+	@Provides
+	@Singleton
+	LogEncrypter provideLogEncrypter(LogEncrypterImpl logEncrypter) {
+		return logEncrypter;
+	}
+
+	@Provides
+	@Singleton
+	LogDecrypter provideLogDecrypter(LogDecrypterImpl logDecrypter) {
+		return logDecrypter;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/login/LoginUtils.java

@@ -1,17 +1,13 @@
 package org.briarproject.briar.android.login;
 
 import android.content.Context;
-import android.graphics.drawable.Drawable;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.R;
 
 import androidx.appcompat.app.AlertDialog;
 
-import static androidx.core.content.ContextCompat.getColor;
-import static androidx.core.content.ContextCompat.getDrawable;
-import static androidx.core.graphics.drawable.DrawableCompat.setTint;
-import static java.util.Objects.requireNonNull;
+import static org.briarproject.briar.android.util.UiUtils.getDialogIcon;
 
 @NotNullByDefault
 class LoginUtils {
@@ -19,9 +15,7 @@ class LoginUtils {
 	static AlertDialog createKeyStrengthenerErrorDialog(Context ctx) {
 		AlertDialog.Builder builder =
 				new AlertDialog.Builder(ctx, R.style.BriarDialogTheme);
-		Drawable icon = getDrawable(ctx, R.drawable.alerts_and_states_error);
-		setTint(requireNonNull(icon), getColor(ctx, R.color.color_primary));
-		builder.setIcon(icon);
+		builder.setIcon(getDialogIcon(ctx, R.drawable.alerts_and_states_error));
 		builder.setTitle(R.string.dialog_title_cannot_check_password);
 		builder.setMessage(R.string.dialog_message_cannot_check_password);
 		builder.setPositiveButton(R.string.ok, null);

briar-android/src/main/java/org/briarproject/briar/android/login/StartupActivity.java

@@ -7,6 +7,7 @@ import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.BriarService;
+import org.briarproject.briar.android.account.NewOrRecoverActivity;
 import org.briarproject.briar.android.account.SetupActivity;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BaseActivity;
@@ -107,7 +108,7 @@ public class StartupActivity extends BaseActivity implements
 	private void onAccountDeleted() {
 		setResult(RESULT_CANCELED);
 		finish();
-		Intent i = new Intent(this, SetupActivity.class);
+		Intent i = new Intent(this, NewOrRecoverActivity.class);
 		i.addFlags(FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_CLEAR_TOP |
 				FLAG_ACTIVITY_CLEAR_TASK | FLAG_ACTIVITY_TASK_ON_HOME);
 		startActivity(i);

briar-android/src/main/java/org/briarproject/briar/android/navdrawer/NavDrawerActivity.java

@@ -2,6 +2,7 @@ package org.briarproject.briar.android.navdrawer;
 
 import android.content.Intent;
 import android.content.res.Configuration;
+import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.os.Bundle;
 import android.view.LayoutInflater;
@@ -59,6 +60,7 @@ import androidx.fragment.app.FragmentTransaction;
 import androidx.lifecycle.MutableLiveData;
 import androidx.lifecycle.ViewModelProvider;
 import androidx.lifecycle.ViewModelProviders;
+import androidx.vectordrawable.graphics.drawable.VectorDrawableCompat;
 import uk.co.samuelwall.materialtaptargetprompt.MaterialTapTargetPrompt;
 
 import static android.view.View.GONE;
@@ -66,6 +68,7 @@ import static android.view.View.VISIBLE;
 import static androidx.core.view.GravityCompat.START;
 import static androidx.drawerlayout.widget.DrawerLayout.LOCK_MODE_LOCKED_CLOSED;
 import static androidx.fragment.app.FragmentManager.POP_BACK_STACK_INCLUSIVE;
+import static androidx.lifecycle.Lifecycle.State.STARTED;
 import static java.util.Objects.requireNonNull;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.RUNNING;
@@ -295,6 +298,12 @@ public class NavDrawerActivity extends BriarActivity implements
 				finish();
 			} else if (fm.getBackStackEntryCount() == 0
 					&& fm.findFragmentByTag(ContactListFragment.TAG) == null) {
+				// don't start fragments in the wrong part of lifecycle (#1904)
+				if (!getLifecycle().getCurrentState().isAtLeast(STARTED)) {
+					LOG.warning("Tried to start contacts fragment in state " +
+							getLifecycle().getCurrentState().name());
+					return;
+				}
 				/*
 				 * This makes sure that the first fragment (ContactListFragment) the
 				 * user sees is the same as the last fragment the user sees before
@@ -433,8 +442,7 @@ public class NavDrawerActivity extends BriarActivity implements
 				Transport t = getItem(position);
 
 				ImageView icon = view.findViewById(R.id.imageView);
-				icon.setImageDrawable(ContextCompat.getDrawable(
-						NavDrawerActivity.this, t.iconDrawable));
+				icon.setImageResource(t.iconDrawable);
 				icon.setColorFilter(ContextCompat.getColor(
 						NavDrawerActivity.this, t.iconColor));
 
@@ -476,11 +484,13 @@ public class NavDrawerActivity extends BriarActivity implements
 	private void showTransportsOnboarding(boolean show, ImageView imageView) {
 		if (show) {
 			int color = resolveColorAttribute(this, R.attr.colorControlNormal);
+			Drawable drawable = VectorDrawableCompat
+					.create(getResources(), R.drawable.transport_tor, null);
 			new MaterialTapTargetPrompt.Builder(NavDrawerActivity.this,
 					R.style.OnboardingDialogTheme).setTarget(imageView)
 					.setPrimaryText(R.string.network_settings_title)
 					.setSecondaryText(R.string.transports_onboarding_text)
-					.setIcon(R.drawable.transport_tor)
+					.setIconDrawable(drawable)
 					.setIconDrawableColourFilter(color)
 					.setBackgroundColour(
 							ContextCompat.getColor(this, R.color.briar_primary))

briar-android/src/main/java/org/briarproject/briar/android/navdrawer/TransportsActivity.java

@@ -141,8 +141,7 @@ public class TransportsActivity extends BriarActivity {
 				Transport t = getItem(position);
 
 				ImageView icon = view.findViewById(R.id.icon);
-				icon.setImageDrawable(ContextCompat.getDrawable(
-						TransportsActivity.this, t.iconDrawable));
+				icon.setImageResource(t.iconDrawable);
 				icon.setColorFilter(ContextCompat.getColor(
 						TransportsActivity.this, t.iconColor));
 

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

@@ -25,6 +25,7 @@ import androidx.lifecycle.ViewModelProvider;
 
 import static android.view.View.GONE;
 import static android.view.View.VISIBLE;
+import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_GROUP_INVITE;
 import static org.briarproject.briar.android.util.UiUtils.observeOnce;
 import static org.briarproject.briar.api.privategroup.PrivateGroupConstants.MAX_GROUP_POST_TEXT_LENGTH;
@@ -80,16 +81,11 @@ public class GroupActivity extends
 		setGroupEnabled(false);
 		viewModel.isDissolved().observe(this, dissolved -> {
 			setGroupEnabled(!dissolved);
-			if (dissolved) onGroupDissolved();
+			// only show dialog when no prior state
+			if (dissolved && state == null) onGroupDissolved();
 		});
 	}
 
-	@Override
-	public void onStart() {
-		super.onStart();
-		viewModel.clearGroupMessageNotifications();
-	}
-
 	@Override
 	public boolean onCreateOptionsMenu(Menu menu) {
 		// Inflate the menu items for use in the action bar
@@ -116,26 +112,26 @@ public class GroupActivity extends
 			startActivity(i);
 			return true;
 		} else if (itemId == R.id.action_group_reveal) {
-			if (viewModel.isCreator().getValue())
+			if (requireNonNull(viewModel.isCreator().getValue()))
 				throw new IllegalStateException();
 			Intent i = new Intent(this, RevealContactsActivity.class);
 			i.putExtra(GROUP_ID, groupId.getBytes());
 			startActivity(i);
 			return true;
 		} else if (itemId == R.id.action_group_invite) {
-			if (!viewModel.isCreator().getValue())
+			if (!requireNonNull(viewModel.isCreator().getValue()))
 				throw new IllegalStateException();
 			Intent i = new Intent(this, GroupInviteActivity.class);
 			i.putExtra(GROUP_ID, groupId.getBytes());
 			startActivityForResult(i, REQUEST_GROUP_INVITE);
 			return true;
 		} else if (itemId == R.id.action_group_leave) {
-			if (viewModel.isCreator().getValue())
+			if (requireNonNull(viewModel.isCreator().getValue()))
 				throw new IllegalStateException();
 			showLeaveGroupDialog();
 			return true;
 		} else if (itemId == R.id.action_group_dissolve) {
-			if (!viewModel.isCreator().getValue())
+			if (!requireNonNull(viewModel.isCreator().getValue()))
 				throw new IllegalStateException();
 			showDissolveGroupDialog();
 			return true;
@@ -158,7 +154,8 @@ public class GroupActivity extends
 
 	@Override
 	public void onReplyClick(GroupMessageItem item) {
-		if (!viewModel.isDissolved().getValue()) super.onReplyClick(item);
+		Boolean isDissolved = viewModel.isDissolved().getValue();
+		if (isDissolved != null && !isDissolved) super.onReplyClick(item);
 	}
 
 	private void setGroupEnabled(boolean enabled) {
@@ -201,7 +198,7 @@ public class GroupActivity extends
 		viewModel.deletePrivateGroup();
 	}
 
-	public void onGroupDissolved() {
+	private void onGroupDissolved() {
 		AlertDialog.Builder builder =
 				new AlertDialog.Builder(this, R.style.BriarDialogTheme);
 		builder.setTitle(getString(R.string.groups_dissolved_dialog_title));

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

@@ -25,7 +25,6 @@ import org.briarproject.briar.android.threaded.ThreadListViewModel;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
 import org.briarproject.briar.api.client.MessageTracker;
 import org.briarproject.briar.api.client.MessageTracker.GroupCount;
-import org.briarproject.briar.api.client.PostHeader;
 import org.briarproject.briar.api.privategroup.GroupMember;
 import org.briarproject.briar.api.privategroup.GroupMessage;
 import org.briarproject.briar.api.privategroup.GroupMessageFactory;
@@ -103,7 +102,10 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 			if (!g.isLocal() && g.getGroupId().equals(groupId)) {
 				LOG.info("Group message received, adding...");
 				GroupMessageItem item = buildItem(g.getHeader(), g.getText());
-				addItem(item);
+				addItem(item, false);
+				// In case the join message comes from the creator,
+				// we need to reload the sharing contacts
+				// in case it was delayed and the sharing count is wrong (#850).
 				if (item instanceof JoinMessageItem &&
 						(((JoinMessageItem) item).isInitial())) {
 					loadSharingContacts();
@@ -133,12 +135,12 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 	}
 
 	@Override
-	public void setGroupId(GroupId groupId) {
-		super.setGroupId(groupId);
+	protected void performInitialLoad() {
+		super.performInitialLoad();
 		loadPrivateGroup(groupId);
 	}
 
-	public void clearGroupMessageNotifications() {
+	protected void clearNotifications() {
 		notificationManager.clearGroupMessageNotification(groupId);
 	}
 
@@ -166,10 +168,28 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 			List<GroupMessageHeader> headers =
 					privateGroupManager.getHeaders(txn, groupId);
 			logDuration(LOG, "Loading headers", start);
-			return createItems(txn, headers, this::buildItem);
+			start = now();
+			List<GroupMessageItem> items = new ArrayList<>();
+			for (GroupMessageHeader header : headers) {
+				items.add(loadItem(txn, header));
+			}
+			logDuration(LOG, "Loading bodies and creating items", start);
+			return items;
 		}, this::setItems);
 	}
 
+	private GroupMessageItem loadItem(Transaction txn,
+			GroupMessageHeader header) throws DbException {
+		String text;
+		if (header instanceof JoinMessageHeader) {
+			// will be looked up later
+			text = "";
+		} else {
+			text = privateGroupManager.getMessageText(txn, header.getId());
+		}
+		return buildItem(header, text);
+	}
+
 	private GroupMessageItem buildItem(GroupMessageHeader header, String text) {
 		if (header instanceof JoinMessageHeader) {
 			return new JoinMessageItem((JoinMessageHeader) header, text);
@@ -177,16 +197,6 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 		return new GroupMessageItem(header, text);
 	}
 
-	@Override
-	protected String loadMessageText(
-			Transaction txn, PostHeader header) throws DbException {
-		if (header instanceof JoinMessageHeader) {
-			// will be looked up later
-			return "";
-		}
-		return privateGroupManager.getMessageText(txn, header.getId());
-	}
-
 	@Override
 	public void createAndStoreMessage(String text,
 			@Nullable MessageId parentId) {
@@ -217,17 +227,15 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 	}
 
 	private void storePost(GroupMessage msg, String text) {
-		runOnDbThread(() -> {
-			try {
-				long start = now();
-				GroupMessageHeader header =
-						privateGroupManager.addLocalMessage(msg);
-				addItemAsync(buildItem(header, text));
-				logDuration(LOG, "Storing group message", start);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
+		runOnDbThread(false, txn -> {
+			long start = now();
+			GroupMessageHeader header =
+					privateGroupManager.addLocalMessage(txn, msg);
+			logDuration(LOG, "Storing group message", start);
+			txn.attach(() ->
+					addItem(buildItem(header, text), true)
+			);
+		}, e -> logException(LOG, WARNING, e));
 	}
 
 	@Override
@@ -242,20 +250,16 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 	}
 
 	public void loadSharingContacts() {
-		runOnDbThread(() -> {
-			try {
-				Collection<GroupMember> members =
-						privateGroupManager.getMembers(groupId);
-				Collection<ContactId> contactIds = new ArrayList<>();
-				for (GroupMember m : members) {
-					if (m.getContactId() != null)
-						contactIds.add(m.getContactId());
-				}
-				sharingController.addAll(contactIds);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
+		runOnDbThread(true, txn -> {
+			Collection<GroupMember> members =
+					privateGroupManager.getMembers(txn, groupId);
+			Collection<ContactId> contactIds = new ArrayList<>();
+			for (GroupMember m : members) {
+				if (m.getContactId() != null)
+					contactIds.add(m.getContactId());
 			}
-		});
+			txn.attach(() -> sharingController.addAll(contactIds));
+		}, e -> logException(LOG, WARNING, e));
 	}
 
 	void deletePrivateGroup() {

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

@@ -16,7 +16,7 @@ class JoinMessageItem extends GroupMessageItem {
 
 	JoinMessageItem(JoinMessageHeader h, String text) {
 		super(h, text);
-		this.isInitial = h.isInitial();
+		isInitial = h.isInitial();
 	}
 
 	@Override

briar-android/src/main/java/org/briarproject/briar/android/reporting/BriarExceptionHandler.java

@@ -1,29 +1,40 @@
 package org.briarproject.briar.android.reporting;
 
-import android.content.Context;
+import android.app.Application;
 import android.os.Process;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.android.logging.LogEncrypter;
 
 import java.lang.Thread.UncaughtExceptionHandler;
 
+import javax.inject.Inject;
+
 import static org.briarproject.briar.android.util.UiUtils.startDevReportActivity;
 
 @NotNullByDefault
-public class BriarExceptionHandler implements UncaughtExceptionHandler {
+class BriarExceptionHandler implements UncaughtExceptionHandler {
 
-	private final Context ctx;
+	private final Application app;
+	private final LogEncrypter logEncrypter;
 	private final long appStartTime;
 
-	public BriarExceptionHandler(Context ctx) {
-		this.ctx = ctx;
-		this.appStartTime = System.currentTimeMillis();
+	@Inject
+	BriarExceptionHandler(Application app, LogEncrypter logEncrypter) {
+		this.app = app;
+		this.logEncrypter = logEncrypter;
+		appStartTime = System.currentTimeMillis();
 	}
 
 	@Override
 	public void uncaughtException(Thread t, Throwable e) {
+		// encrypt logs to disk before handing over to new process
+		// the intent has limited space, so we can't reliably store them there.
+		byte[] logKey = logEncrypter.encryptLogs();
+
 		// activity runs in its own process, so we can kill the old one
-		startDevReportActivity(ctx, CrashReportActivity.class, e, appStartTime);
+		startDevReportActivity(app.getApplicationContext(),
+				CrashReportActivity.class, e, appStartTime, logKey);
 		Process.killProcess(Process.myPid());
 		System.exit(10);
 	}

briar-android/src/main/java/org/briarproject/briar/android/reporting/BriarReportCollector.java

@@ -25,8 +25,6 @@ import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.BuildConfig;
 import org.briarproject.briar.R;
-import org.briarproject.briar.android.BriarApplication;
-import org.briarproject.briar.android.logging.BriefLogFormatter;
 import org.briarproject.briar.android.reporting.ReportData.MultiReportInfo;
 import org.briarproject.briar.android.reporting.ReportData.ReportItem;
 import org.briarproject.briar.android.reporting.ReportData.SingleReportInfo;
@@ -41,8 +39,6 @@ import java.net.InetAddress;
 import java.net.UnknownHostException;
 import java.text.SimpleDateFormat;
 import java.util.Date;
-import java.util.logging.Formatter;
-import java.util.logging.LogRecord;
 
 import javax.annotation.concurrent.Immutable;
 
@@ -74,8 +70,8 @@ class BriarReportCollector {
 		this.ctx = ctx;
 	}
 
-	public ReportData collectReportData(@Nullable Throwable t,
-			long appStartTime) {
+	ReportData collectReportData(@Nullable Throwable t, long appStartTime,
+			String logs) {
 		ReportData reportData = new ReportData()
 				.add(getBasicInfo(t))
 				.add(getDeviceInfo());
@@ -86,7 +82,7 @@ class BriarReportCollector {
 				.add(getStorage())
 				.add(getConnectivity())
 				.add(getBuildConfig())
-				.add(getLogcat())
+				.add(getLogcat(logs))
 				.add(getDeviceFeatures());
 	}
 
@@ -313,15 +309,8 @@ class BriarReportCollector {
 				buildConfig);
 	}
 
-	private ReportItem getLogcat() {
-		BriarApplication app = (BriarApplication) ctx.getApplicationContext();
-		StringBuilder sb = new StringBuilder();
-		Formatter formatter = new BriefLogFormatter();
-		for (LogRecord record : app.getRecentLogRecords()) {
-			sb.append(formatter.format(record)).append('\n');
-		}
-		return new ReportItem("Logcat", R.string.dev_report_logcat,
-				sb.toString());
+	private ReportItem getLogcat(String logs) {
+		return new ReportItem("Logcat", R.string.dev_report_logcat, logs);
 	}
 
 	private ReportItem getDeviceFeatures() {

briar-android/src/main/java/org/briarproject/briar/android/reporting/CrashReportActivity.java

@@ -35,6 +35,7 @@ public class CrashReportActivity extends BaseActivity
 
 	public static final String EXTRA_THROWABLE = "throwable";
 	public static final String EXTRA_APP_START_TIME = "appStartTime";
+	public static final String EXTRA_APP_LOGCAT = "logcat";
 
 	@Inject
 	ViewModelProvider.Factory viewModelFactory;
@@ -56,7 +57,8 @@ public class CrashReportActivity extends BaseActivity
 		Intent intent = getIntent();
 		Throwable t = (Throwable) intent.getSerializableExtra(EXTRA_THROWABLE);
 		long appStartTime = intent.getLongExtra(EXTRA_APP_START_TIME, -1);
-		viewModel.init(t, appStartTime);
+		byte[] logKey = intent.getByteArrayExtra(EXTRA_APP_LOGCAT);
+		viewModel.init(t, appStartTime, logKey);
 		viewModel.getShowReport().observeEvent(this, show -> {
 			if (show) displayFragment(true);
 		});

briar-android/src/main/java/org/briarproject/briar/android/reporting/DevReportModule.java

@@ -15,4 +15,8 @@ public abstract class DevReportModule {
 	@ViewModelKey(ReportViewModel.class)
 	abstract ViewModel bindReportViewModel(ReportViewModel reportViewModel);
 
+	@Binds
+	abstract Thread.UncaughtExceptionHandler bindUncaughtExceptionHandler(
+			BriarExceptionHandler handler);
+
 }

briar-android/src/main/java/org/briarproject/briar/android/reporting/ReportViewModel.java

@@ -11,6 +11,9 @@ import org.briarproject.bramble.api.plugin.TorConstants;
 import org.briarproject.bramble.api.reporting.DevReporter;
 import org.briarproject.bramble.util.AndroidUtils;
 import org.briarproject.briar.R;
+import org.briarproject.briar.android.logging.BriefLogFormatter;
+import org.briarproject.briar.android.logging.CachingLogHandler;
+import org.briarproject.briar.android.logging.LogDecrypter;
 import org.briarproject.briar.android.reporting.ReportData.MultiReportInfo;
 import org.briarproject.briar.android.viewmodel.LiveEvent;
 import org.briarproject.briar.android.viewmodel.MutableLiveEvent;
@@ -19,6 +22,7 @@ import org.json.JSONException;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.util.UUID;
+import java.util.logging.Formatter;
 import java.util.logging.Logger;
 
 import javax.inject.Inject;
@@ -36,13 +40,16 @@ import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
+import static org.briarproject.briar.android.logging.BriefLogFormatter.formatLog;
 
 @NotNullByDefault
-public class ReportViewModel extends AndroidViewModel {
+class ReportViewModel extends AndroidViewModel {
 
 	private static final Logger LOG =
 			getLogger(ReportViewModel.class.getName());
 
+	private final CachingLogHandler logHandler;
+	private final LogDecrypter logDecrypter;
 	private final BriarReportCollector collector;
 	private final DevReporter reporter;
 	private final PluginManager pluginManager;
@@ -58,18 +65,39 @@ public class ReportViewModel extends AndroidViewModel {
 	private boolean isFeedback;
 
 	@Inject
-	public ReportViewModel(@NonNull Application application,
-			DevReporter reporter, PluginManager pluginManager) {
+	ReportViewModel(@NonNull Application application,
+			CachingLogHandler logHandler,
+			LogDecrypter logDecrypter,
+			DevReporter reporter,
+			PluginManager pluginManager) {
 		super(application);
-		this.collector = new BriarReportCollector(application);
+		collector = new BriarReportCollector(application);
+		this.logHandler = logHandler;
+		this.logDecrypter = logDecrypter;
 		this.reporter = reporter;
 		this.pluginManager = pluginManager;
 	}
 
-	void init(@Nullable Throwable t, long appStartTime) {
+	void init(@Nullable Throwable t, long appStartTime,
+			@Nullable byte[] logKey) {
 		isFeedback = t == null;
 		if (reportData.getValue() == null) new SingleShotAndroidExecutor(() -> {
-			ReportData data = collector.collectReportData(t, appStartTime);
+			String decryptedLogs;
+			if (isFeedback) {
+				Formatter formatter = new BriefLogFormatter();
+				decryptedLogs =
+						formatLog(formatter, logHandler.getRecentLogRecords());
+			} else {
+				decryptedLogs = logDecrypter.decryptLogs(logKey);
+				if (decryptedLogs == null) {
+					// error decrypting logs, get logs from this process
+					Formatter formatter = new BriefLogFormatter();
+					decryptedLogs = formatLog(formatter,
+							logHandler.getRecentLogRecords());
+				}
+			}
+			ReportData data =
+					collector.collectReportData(t, appStartTime, decryptedLogs);
 			reportData.postValue(data);
 		}).start();
 	}
@@ -110,8 +138,8 @@ public class ReportViewModel extends AndroidViewModel {
 	}
 
 	/**
-	 * The content of the report
-	 * that will be loaded after {@link #init(Throwable, long)} was called.
+	 * The content of the report that will be loaded after
+	 * {@link #init(Throwable, long, byte[])} was called.
 	 */
 	LiveData<ReportData> getReportData() {
 		return reportData;

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

@@ -1,7 +1,6 @@
 package org.briarproject.briar.android.sharing;
 
 import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
@@ -28,7 +27,7 @@ public interface SharingController {
 	/**
 	 * Adds a collection of contacts to be tracked.
 	 */
-	@DatabaseExecutor
+	@UiThread
 	void addAll(Collection<ContactId> contacts);
 
 	/**

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

@@ -2,14 +2,12 @@ package org.briarproject.briar.android.sharing;
 
 import org.briarproject.bramble.api.connection.ConnectionRegistry;
 import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
 import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
-import org.briarproject.bramble.api.system.AndroidExecutor;
 
 import java.util.Collection;
 import java.util.HashSet;
@@ -26,7 +24,6 @@ public class SharingControllerImpl implements SharingController, EventListener {
 
 	private final EventBus eventBus;
 	private final ConnectionRegistry connectionRegistry;
-	private final AndroidExecutor executor;
 
 	// UI thread
 	private final Set<ContactId> contacts = new HashSet<>();
@@ -35,11 +32,9 @@ public class SharingControllerImpl implements SharingController, EventListener {
 
 	@Inject
 	SharingControllerImpl(EventBus eventBus,
-			ConnectionRegistry connectionRegistry,
-			AndroidExecutor executor) {
+			ConnectionRegistry connectionRegistry) {
 		this.eventBus = eventBus;
 		this.connectionRegistry = connectionRegistry;
-		this.executor = executor;
 		eventBus.addListener(this);
 	}
 
@@ -78,13 +73,11 @@ public class SharingControllerImpl implements SharingController, EventListener {
 		return online;
 	}
 
+	@UiThread
 	@Override
-	@DatabaseExecutor
 	public void addAll(Collection<ContactId> c) {
-		executor.runOnUiThread(() -> {
-			contacts.addAll(c);
-			updateLiveData();
-		});
+		contacts.addAll(c);
+		updateLiveData();
 	}
 
 	@UiThread

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/CustodianHelpRecoverActivity.java

@@ -0,0 +1,67 @@
+package org.briarproject.briar.android.socialbackup;
+
+import android.content.Intent;
+import android.os.Bundle;
+import android.widget.Toast;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.activity.BriarActivity;
+import org.briarproject.briar.android.fragment.BaseFragment;
+import org.briarproject.briar.api.socialbackup.SocialBackupManager;
+
+import javax.inject.Inject;
+
+import static org.briarproject.briar.android.conversation.ConversationActivity.CONTACT_ID;
+
+public class CustodianHelpRecoverActivity extends BriarActivity implements
+		BaseFragment.BaseFragmentListener, CustodianScanQrButtonListener {
+	@Override
+	public void injectActivity(ActivityComponent component) {
+		component.inject(this);
+	}
+
+	@Inject
+	public SocialBackupManager socialBackupManager;
+
+	@Inject
+	public DatabaseComponent db;
+
+	@Override
+	public void onCreate(Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		setContentView(R.layout.activity_recover); // TODO change this
+
+		Intent intent = getIntent();
+		int id = intent.getIntExtra(CONTACT_ID, -1);
+		if (id == -1) throw new IllegalStateException("No ContactId");
+		ContactId contactId = new ContactId(id);
+
+		// check if we have a shard for this secret owner
+		try {
+			db.transaction(false, txn -> {
+				if (!socialBackupManager.amCustodian(txn, contactId)) {
+					throw new DbException();
+				}
+				CustodianRecoveryModeExplainerFragment fragment =
+						new CustodianRecoveryModeExplainerFragment();
+				showInitialFragment(fragment);
+			});
+		} catch (DbException e) {
+			// TODO improve this
+			Toast.makeText(this,
+					"You do not hold a backup shard from this contact",
+					Toast.LENGTH_SHORT).show();
+			finish();
+		}
+	}
+
+	@Override
+	public void scanQrButtonClicked() {
+		// TODO scan qr code
+		finish();
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/CustodianRecoveryModeExplainerFragment.java

@@ -0,0 +1,51 @@
+package org.briarproject.briar.android.socialbackup;
+
+import android.content.Context;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Button;
+
+import org.briarproject.briar.android.fragment.BaseFragment;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import org.briarproject.briar.R;
+
+public class CustodianRecoveryModeExplainerFragment extends BaseFragment {
+
+	protected CustodianScanQrButtonListener listener;
+
+	public static final String TAG = CustodianRecoveryModeExplainerFragment.class.getName();
+
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		requireActivity().setTitle(R.string.title_help_recover);
+	}
+
+	@Nullable
+	@Override
+	public View onCreateView(@NonNull LayoutInflater inflater, @Nullable
+			ViewGroup container, @Nullable Bundle savedInstanceState) {
+		View view = inflater.inflate(R.layout.fragment_recovery_custodian_explainer,
+				container, false);
+
+		Button button = view.findViewById(R.id.button);
+		button.setOnClickListener(e -> listener.scanQrButtonClicked());
+		return view;
+	}
+
+	@Override
+	public void onAttach(Context context) {
+		super.onAttach(context);
+		listener = (CustodianScanQrButtonListener) context;
+	}
+
+	@Override
+	public String getUniqueTag() {
+		return TAG;
+	}
+}
+

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/CustodianScanQrButtonListener.java

@@ -0,0 +1,8 @@
+package org.briarproject.briar.android.socialbackup;
+
+import androidx.annotation.UiThread;
+
+public interface CustodianScanQrButtonListener {
+	@UiThread
+	void scanQrButtonClicked();
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/CustodianSelectorFragment.java

@@ -0,0 +1,93 @@
+package org.briarproject.briar.android.socialbackup;
+
+import android.os.Bundle;
+import android.view.MenuItem;
+import android.widget.Toast;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.socialbackup.creation.CreateBackupController;
+import org.briarproject.briar.android.contactselection.BaseContactSelectorAdapter;
+import org.briarproject.briar.android.contactselection.ContactSelectorController;
+import org.briarproject.briar.android.contactselection.ContactSelectorFragment;
+import org.briarproject.briar.android.contactselection.SelectableContactItem;
+import org.briarproject.briar.android.controller.handler.ResultExceptionHandler;
+
+import java.util.Collection;
+
+import javax.inject.Inject;
+
+import androidx.annotation.Nullable;
+
+import static java.util.Objects.requireNonNull;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public class CustodianSelectorFragment extends ContactSelectorFragment {
+
+	public static final String TAG = CustodianSelectorFragment.class.getName();
+
+	@Inject
+	CreateBackupController controller;
+
+	public static CustodianSelectorFragment newInstance() {
+		Bundle args = new Bundle();
+
+		CustodianSelectorFragment fragment = new CustodianSelectorFragment();
+		fragment.setArguments(args);
+
+		return fragment;
+	}
+
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+	}
+
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+
+		requireActivity().setTitle(R.string.title_select_custodians);
+	}
+
+	@Override
+	protected ContactSelectorController<SelectableContactItem> getController() {
+		return controller;
+	}
+
+	@Override
+	public String getUniqueTag() {
+		return TAG;
+	}
+
+	@Override
+	protected void onSelectionChanged() {
+		super.onSelectionChanged();
+		if (menu == null) return;
+		MenuItem item = menu.findItem(R.id.action_contacts_selected);
+		if (item == null) return;
+
+		BaseContactSelectorAdapter a = adapter;
+		selectedContacts = a.getSelectedContactIds();
+
+		int n = selectedContacts.size();
+		int min = 2;
+		boolean enough = n >= min;
+
+		item.setVisible(enough);
+		if (n == 0) {
+			Toast.makeText(getContext(), String.format(getString(R.string.select_at_least_n_contacts), min),
+					Toast.LENGTH_SHORT).show();
+		} else if (n < min) {
+			Toast.makeText(getContext(), String.format(getString(R.string.select_at_least_n_more_contacts), min - n),
+					Toast.LENGTH_SHORT).show();
+		}
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/DarkCrystalImpl.java

@@ -0,0 +1,56 @@
+package org.briarproject.briar.android.socialbackup;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.api.socialbackup.Shard;
+import org.briarproject.briar.api.socialbackup.DarkCrystal;
+import org.magmacollective.darkcrystal.secretsharingwrapper.SecretSharingWrapper;
+
+import java.security.GeneralSecurityException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Random;
+
+import javax.inject.Inject;
+
+import dagger.Provides;
+
+import static org.briarproject.briar.socialbackup.SocialBackupConstants.SECRET_ID_BYTES;
+
+@NotNullByDefault
+public class DarkCrystalImpl implements DarkCrystal {
+
+    @Inject
+	DarkCrystalImpl() {
+	}
+
+	@Override
+	public List<Shard> createShards(SecretKey secret, int numShards,
+			int threshold) {
+		Random random = new Random();
+		byte[] secretId = new byte[SECRET_ID_BYTES];
+		random.nextBytes(secretId);
+		List<byte[]> shardsBytes = SecretSharingWrapper.share(secret.getBytes(), numShards, threshold);
+		List<Shard> shards = new ArrayList<>(numShards);
+		for (byte[] shardBytes : shardsBytes) {
+			shards.add(new Shard(secretId, shardBytes));
+		}
+		return shards;
+	}
+
+	@Override
+	public SecretKey combineShards(List<Shard> shards) throws
+			GeneralSecurityException {
+		// Check each shard has the same secret Id
+		byte[] secretId = shards.get(0).getSecretId();
+		for (Shard shard : shards) {
+			if (!Arrays.equals(shard.getSecretId(), secretId)) throw new GeneralSecurityException();
+		}
+        List<byte[]> shardsBytes = new ArrayList<>(shards.size());
+		for (Shard shard : shards) {
+			shardsBytes.add(shard.getShard());
+		}
+		byte[] secretBytes = SecretSharingWrapper.combine(shardsBytes);
+		return new SecretKey(secretBytes);
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/DistributedBackupActivity.java

@@ -0,0 +1,91 @@
+package org.briarproject.briar.android.socialbackup;
+
+import android.os.Bundle;
+import android.widget.Toast;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.activity.BriarActivity;
+import org.briarproject.briar.android.contactselection.ContactSelectorListener;
+import org.briarproject.briar.android.fragment.BaseFragment;
+import org.briarproject.briar.api.socialbackup.BackupMetadata;
+import org.briarproject.briar.api.socialbackup.SocialBackupManager;
+
+import java.util.Collection;
+import java.util.List;
+
+import javax.inject.Inject;
+
+public class DistributedBackupActivity extends BriarActivity implements
+		BaseFragment.BaseFragmentListener, ContactSelectorListener,
+		ThresholdDefinedListener,
+		ShardsSentFragment.ShardsSentDismissedListener {
+
+	private Collection<ContactId> custodians;
+
+	@Inject
+	public SocialBackupManager socialBackupManager;
+
+	@Inject
+	public DatabaseComponent db;
+
+	@Override
+	public void injectActivity(ActivityComponent component) {
+		component.inject(this);
+	}
+
+	@Override
+	public void onCreate(Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		setContentView(R.layout.activity_distributed_backup);
+
+		try {
+			db.transaction(false, txn -> {
+				BackupMetadata backupMetadata =
+						socialBackupManager.getBackupMetadata(txn);
+				if (backupMetadata == null) throw new DbException();
+				ExistingBackupFragment fragment =
+						ExistingBackupFragment.newInstance(backupMetadata);
+				showInitialFragment(fragment);
+			});
+		} catch (DbException e) {
+			CustodianSelectorFragment fragment =
+					CustodianSelectorFragment.newInstance();
+			showInitialFragment(fragment);
+		}
+	}
+
+	@Override
+	public void contactsSelected(Collection<ContactId> contacts) {
+		Toast.makeText(this,
+				String.format("selected %d contacts", contacts.size()),
+				Toast.LENGTH_SHORT).show();
+		custodians = contacts;
+		ThresholdSelectorFragment fragment =
+				ThresholdSelectorFragment.newInstance(contacts.size());
+		showNextFragment(fragment);
+	}
+
+	@Override
+	public void thresholdDefined(int threshold) {
+		try {
+			db.transaction(false, txn -> {
+				socialBackupManager
+						.createBackup(txn, (List<ContactId>) custodians,
+								threshold);
+				ShardsSentFragment fragment = new ShardsSentFragment();
+				showNextFragment(fragment);
+			});
+		} catch (DbException e) {
+			e.printStackTrace();
+		}
+	}
+
+	@Override
+	public void shardsSentDismissed() {
+		finish();
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/ExistingBackupFragment.java

@@ -0,0 +1,85 @@
+package org.briarproject.briar.android.socialbackup;
+
+import android.content.Context;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.fragment.BaseFragment;
+import org.briarproject.briar.api.socialbackup.BackupMetadata;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+public class ExistingBackupFragment extends BaseFragment {
+
+	private static final String THRESHOLD = "threshold";
+	private static final String CUSTODIANS = "custodians";
+	public static final String TAG = ExistingBackupFragment.class.getName();
+
+	public static ExistingBackupFragment newInstance(
+			BackupMetadata backupMetadata) {
+		Bundle bundle = new Bundle();
+		List<Author> custodians = backupMetadata.getCustodians();
+		ArrayList custodianNames = new ArrayList();
+	    for (Author custodian : custodians) {
+	    	custodianNames.add(custodian.getName());
+	    }
+	    bundle.putStringArrayList(CUSTODIANS, custodianNames);
+		bundle.putInt(THRESHOLD, backupMetadata.getThreshold());
+		ExistingBackupFragment fragment = new ExistingBackupFragment();
+		fragment.setArguments(bundle);
+		return fragment;
+	}
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		requireActivity().setTitle(R.string.title_distributed_backup);
+
+	}
+
+	@Nullable
+	@Override
+	public View onCreateView(@NonNull LayoutInflater inflater, @Nullable
+			ViewGroup container, @Nullable Bundle savedInstanceState) {
+		View view = inflater.inflate(R.layout.fragment_existing_backup,
+				container, false);
+		Bundle args = requireArguments();
+        ArrayList<String> custodianNames = args.getStringArrayList(CUSTODIANS);
+        String custodianNamesString = "";
+        for (String custodianName : custodianNames) {
+          	custodianNamesString += custodianName + ", ";
+        }
+        TextView textViewThreshold = view.findViewById(R.id.textViewThreshold);
+        textViewThreshold.setText(String.format("%d of %d contacts needed to restore account", args.getInt(THRESHOLD), custodianNames.size()));
+        TextView textViewCustodians = view.findViewById(R.id.textViewCustodians);
+        textViewCustodians.setText(custodianNamesString);
+		return view;
+	}
+
+	@Override
+	public void onAttach(Context context) {
+		super.onAttach(context);
+//		listener = (ShardsSentDismissedListener) context;
+	}
+
+
+	@Override
+	public String getUniqueTag() {
+		return TAG;
+	}
+
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/ExplainerDismissedListener.java

@@ -0,0 +1,8 @@
+package org.briarproject.briar.android.socialbackup;
+
+import androidx.annotation.UiThread;
+
+public interface ExplainerDismissedListener {
+	@UiThread
+	void explainerDismissed();
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/OwnerRecoveryModeExplainerFragment.java

@@ -0,0 +1,58 @@
+package org.briarproject.briar.android.socialbackup;
+
+import android.content.Context;
+import android.os.Bundle;
+
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Button;
+
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.fragment.BaseFragment;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+public class OwnerRecoveryModeExplainerFragment extends BaseFragment {
+
+	protected ExplainerDismissedListener listener;
+	public static final String TAG =
+			OwnerRecoveryModeExplainerFragment.class.getName();
+
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		requireActivity().setTitle(R.string.title_recovery_mode);
+	}
+
+	@Nullable
+	@Override
+	public View onCreateView(@NonNull LayoutInflater inflater,
+			@Nullable ViewGroup container,
+			@Nullable Bundle savedInstanceState) {
+		View view = inflater.inflate(R.layout.fragment_recovery_owner_explainer,
+				container, false);
+		Button button = view.findViewById(R.id.beginButton);
+		button.setOnClickListener(e -> listener.explainerDismissed());
+
+		return view;
+	}
+
+	@Override
+	public void onAttach(Context context) {
+		super.onAttach(context);
+		listener = (ExplainerDismissedListener) context;
+	}
+
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+	}
+
+	@Override
+	public String getUniqueTag() {
+		return TAG;
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/OwnerRecoveryModeMainFragment.java

@@ -0,0 +1,73 @@
+package org.briarproject.briar.android.socialbackup;
+
+import android.content.Context;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Button;
+import android.widget.TextView;
+
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.fragment.BaseFragment;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+public class OwnerRecoveryModeMainFragment extends BaseFragment {
+
+	protected ScanQrButtonListener listener;
+
+	public static final String NUM_RECOVERED = "num_recovered";
+
+	public static final String TAG =
+			OwnerRecoveryModeMainFragment.class.getName();
+
+	public static OwnerRecoveryModeMainFragment newInstance(int numRecovered) {
+		Bundle args = new Bundle();
+		args.putInt(NUM_RECOVERED, numRecovered);
+		OwnerRecoveryModeMainFragment fragment =
+				new OwnerRecoveryModeMainFragment();
+		fragment.setArguments(args);
+		return fragment;
+	}
+
+	private int numShards;
+
+	@Override
+	public String getUniqueTag() {
+		return TAG;
+	}
+
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		requireActivity().setTitle(R.string.title_recovery_mode);
+
+		Bundle args = requireArguments();
+		numShards = args.getInt(NUM_RECOVERED);
+	}
+
+	@Nullable
+	@Override
+	public View onCreateView(@NonNull LayoutInflater inflater,
+			@Nullable ViewGroup container,
+			@Nullable Bundle savedInstanceState) {
+		View view = inflater.inflate(R.layout.fragment_recovery_owner_main,
+				container, false);
+
+		TextView textViewCount = view.findViewById(R.id.textViewShardCount);
+		textViewCount.setText(String.format("%d", numShards));
+
+		Button button = view.findViewById(R.id.button);
+		button.setOnClickListener(e -> listener.scanQrButtonClicked());
+		return view;
+	}
+
+	@Override
+	public void onAttach(Context context) {
+		super.onAttach(context);
+		listener = (ScanQrButtonListener) context;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/RecoverActivity.java

@@ -0,0 +1,179 @@
+package org.briarproject.briar.android.socialbackup;
+
+import android.os.Bundle;
+import android.widget.Toast;
+
+import org.briarproject.bramble.api.keyagreement.KeyAgreementResult;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.activity.BaseActivity;
+import org.briarproject.briar.android.fragment.BaseFragment;
+
+import javax.annotation.Nullable;
+
+import androidx.annotation.UiThread;
+import androidx.core.app.ActivityCompat;
+
+import static android.Manifest.permission.CAMERA;
+import static android.content.pm.PackageManager.PERMISSION_GRANTED;
+import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_PERMISSION_CAMERA_LOCATION;
+
+public class RecoverActivity extends BaseActivity implements
+		BaseFragment.BaseFragmentListener, ExplainerDismissedListener,
+		ScanQrButtonListener, ShardQrCodeFragment.ShardQrCodeEventListener {
+
+	@Override
+	public void keyAgreementFailed() {
+
+	}
+
+	@Nullable
+	@Override
+	public String keyAgreementWaiting() {
+		return null;
+	}
+
+	@Nullable
+	@Override
+	public String keyAgreementStarted() {
+		return null;
+	}
+
+	@Override
+	public void keyAgreementAborted(boolean remoteAborted) {
+
+	}
+
+	@Nullable
+	@Override
+	public String keyAgreementFinished(KeyAgreementResult result) {
+		return null;
+	}
+
+	private enum Permission {
+		UNKNOWN, GRANTED, SHOW_RATIONALE, PERMANENTLY_DENIED
+	}
+
+	private Permission cameraPermission = Permission.UNKNOWN;
+
+
+	private int numRecovered;
+
+	@Override
+	public void onCreate(Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		setContentView(R.layout.activity_recover);
+
+		numRecovered = 0; // TODO - retrieve this from somewhere
+
+		// only show the explainer if we have no shards
+		if (numRecovered == 0) {
+			OwnerRecoveryModeExplainerFragment fragment =
+					new OwnerRecoveryModeExplainerFragment();
+			showInitialFragment(fragment);
+		} else {
+			OwnerRecoveryModeMainFragment fragment =
+					OwnerRecoveryModeMainFragment.newInstance(numRecovered);
+			showInitialFragment(fragment);
+		}
+	}
+
+	@Override
+	public void injectActivity(ActivityComponent component) {
+		component.inject(this);
+	}
+
+	@Override
+	public void explainerDismissed() {
+		OwnerRecoveryModeMainFragment fragment =
+				OwnerRecoveryModeMainFragment.newInstance(numRecovered);
+		showNextFragment(fragment);
+	}
+
+	@Override
+	public void scanQrButtonClicked() {
+		if (checkPermissions()) showQrCodeFragment();
+	}
+
+
+	private void showQrCodeFragment() {
+		ShardQrCodeFragment f = ShardQrCodeFragment.newInstance();
+		showNextFragment(f);
+	}
+
+	private void requestPermissions() {
+		String[] permissions = new String[] {CAMERA};
+		ActivityCompat.requestPermissions(this, permissions,
+				REQUEST_PERMISSION_CAMERA_LOCATION);
+	}
+
+	@Override
+	@UiThread
+	public void onRequestPermissionsResult(int requestCode,
+			String[] permissions, int[] grantResults) {
+		if (requestCode != REQUEST_PERMISSION_CAMERA_LOCATION)
+			throw new AssertionError();
+		if (gotPermission(CAMERA, permissions, grantResults)) {
+			cameraPermission = Permission.GRANTED;
+		} else if (shouldShowRationale(CAMERA)) {
+			cameraPermission = Permission.SHOW_RATIONALE;
+		} else {
+			cameraPermission = Permission.PERMANENTLY_DENIED;
+		}
+		// If a permission dialog has been shown, showing the QR code fragment
+		// on this call path would cause a crash due to
+		// https://code.google.com/p/android/issues/detail?id=190966.
+		// In that case the isResumed flag prevents the fragment from being
+		// shown here, and showQrCodeFragmentIfAllowed() will be called again
+		// from onPostResume().
+		if (checkPermissions()) showQrCodeFragment();
+	}
+
+	private boolean gotPermission(String permission, String[] permissions,
+			int[] grantResults) {
+		for (int i = 0; i < permissions.length; i++) {
+			if (permission.equals(permissions[i]))
+				return grantResults[i] == PERMISSION_GRANTED;
+		}
+		return false;
+	}
+
+	private boolean shouldShowRationale(String permission) {
+		return ActivityCompat.shouldShowRequestPermissionRationale(this,
+				permission);
+	}
+
+	private boolean checkPermissions() {
+		if (areEssentialPermissionsGranted()) return true;
+		// If an essential permission has been permanently denied, ask the
+		// user to change the setting
+		if (cameraPermission == Permission.PERMANENTLY_DENIED) {
+			Toast.makeText(this,
+					"camera permission is denied",
+					Toast.LENGTH_SHORT).show();
+//			showDenialDialog(R.string.permission_camera_title,
+//					R.string.permission_camera_denied_body);
+			return false;
+		}
+		if (cameraPermission == Permission.SHOW_RATIONALE) {
+//			showRationale(R.string.permission_camera_title,
+//					R.string.permission_camera_request_body);
+			Toast.makeText(this,
+					"camera permission - show rationale",
+					Toast.LENGTH_SHORT).show();
+		} else {
+			requestPermissions();
+		}
+		return false;
+	}
+
+	@Override
+	@Deprecated
+	public void runOnDbThread(Runnable runnable) {
+		throw new RuntimeException("Don't use this deprecated method here.");
+	}
+
+	private boolean areEssentialPermissionsGranted() {
+		return cameraPermission == Permission.GRANTED;
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/ScanQrButtonListener.java

@@ -0,0 +1,8 @@
+package org.briarproject.briar.android.socialbackup;
+
+import androidx.annotation.UiThread;
+
+public interface ScanQrButtonListener {
+	@UiThread
+	void scanQrButtonClicked();
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/ShardQrCodeFragment.java

@@ -0,0 +1,381 @@
+package org.briarproject.briar.android.socialbackup;
+
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.os.Bundle;
+import android.util.DisplayMetrics;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.LinearLayout;
+import android.widget.TextView;
+import android.widget.Toast;
+
+import com.google.zxing.Result;
+
+import org.briarproject.bramble.api.UnsupportedVersionException;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.keyagreement.KeyAgreementResult;
+import org.briarproject.bramble.api.keyagreement.KeyAgreementTask;
+import org.briarproject.bramble.api.keyagreement.Payload;
+import org.briarproject.bramble.api.keyagreement.PayloadEncoder;
+import org.briarproject.bramble.api.keyagreement.PayloadParser;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementAbortedEvent;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementFailedEvent;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementFinishedEvent;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementListeningEvent;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementStartedEvent;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementWaitingEvent;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.fragment.BaseEventFragment;
+import org.briarproject.briar.android.keyagreement.CameraException;
+import org.briarproject.briar.android.keyagreement.CameraView;
+import org.briarproject.briar.android.keyagreement.ContactExchangeErrorFragment;
+import org.briarproject.briar.android.keyagreement.QrCodeDecoder;
+import org.briarproject.briar.android.keyagreement.QrCodeUtils;
+import org.briarproject.briar.android.view.QrCodeView;
+
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+import javax.inject.Provider;
+
+import androidx.annotation.UiThread;
+
+import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_NOSENSOR;
+import static android.view.View.INVISIBLE;
+import static android.view.View.VISIBLE;
+import static android.view.ViewGroup.LayoutParams.MATCH_PARENT;
+import static android.widget.LinearLayout.HORIZONTAL;
+import static android.widget.Toast.LENGTH_LONG;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public class ShardQrCodeFragment extends BaseEventFragment
+		implements QrCodeDecoder.ResultCallback, QrCodeView.FullscreenListener {
+
+	static final String TAG = org.briarproject.briar.android.keyagreement.KeyAgreementFragment.class.getName();
+
+	private static final Logger LOG = Logger.getLogger(TAG);
+	@SuppressWarnings("CharsetObjectCanBeUsed") // Requires minSdkVersion >= 19
+	private static final Charset ISO_8859_1 = Charset.forName("ISO-8859-1");
+
+	@Inject
+	Provider<KeyAgreementTask> keyAgreementTaskProvider;
+	@Inject
+	PayloadEncoder payloadEncoder;
+	@Inject
+	PayloadParser payloadParser;
+	@Inject
+	@IoExecutor
+	Executor ioExecutor;
+	@Inject
+	EventBus eventBus;
+
+	private CameraView cameraView;
+	private LinearLayout cameraOverlay;
+	private View statusView;
+	private QrCodeView qrCodeView;
+	private TextView status;
+
+	private boolean gotRemotePayload;
+	private volatile boolean gotLocalPayload;
+	private KeyAgreementTask task;
+	private ShardQrCodeEventListener
+			listener;
+
+	public static ShardQrCodeFragment newInstance() {
+		Bundle args = new Bundle();
+		ShardQrCodeFragment
+				fragment = new ShardQrCodeFragment();
+		fragment.setArguments(args);
+		return fragment;
+	}
+
+	@Override
+	public void onAttach(Context context) {
+		super.onAttach(context);
+		listener = (ShardQrCodeEventListener) context;
+	}
+
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+	}
+
+	@Override
+	public String getUniqueTag() {
+		return TAG;
+	}
+
+	@Nullable
+	@Override
+	public View onCreateView(LayoutInflater inflater,
+			@Nullable ViewGroup container,
+			@Nullable Bundle savedInstanceState) {
+		return inflater.inflate(R.layout.fragment_keyagreement_qr, container,
+				false);
+	}
+
+	@Override
+	public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
+		super.onViewCreated(view, savedInstanceState);
+		cameraView = view.findViewById(R.id.camera_view);
+		cameraOverlay = view.findViewById(R.id.camera_overlay);
+		statusView = view.findViewById(R.id.status_container);
+		status = view.findViewById(R.id.connect_status);
+		qrCodeView = view.findViewById(R.id.qr_code_view);
+		qrCodeView.setFullscreenListener(this);
+	}
+
+	@Override
+	public void onActivityCreated(@Nullable Bundle savedInstanceState) {
+		super.onActivityCreated(savedInstanceState);
+		requireActivity().setRequestedOrientation(SCREEN_ORIENTATION_NOSENSOR);
+		cameraView.setPreviewConsumer(new QrCodeDecoder(this));
+	}
+
+	@Override
+	public void onStart() {
+		super.onStart();
+		try {
+			cameraView.start();
+		} catch (CameraException e) {
+			logCameraExceptionAndFinish(e);
+		}
+		startListening();
+	}
+
+	@Override
+	public void setFullscreen(boolean fullscreen) {
+		LinearLayout.LayoutParams statusParams, qrCodeParams;
+		if (fullscreen) {
+			// Grow the QR code view to fill its parent
+			statusParams = new LinearLayout.LayoutParams(0, 0, 0f);
+			qrCodeParams = new LinearLayout.LayoutParams(MATCH_PARENT, MATCH_PARENT, 1f);
+		} else {
+			// Shrink the QR code view to fill half its parent
+			if (cameraOverlay.getOrientation() == HORIZONTAL) {
+				statusParams = new LinearLayout.LayoutParams(0, MATCH_PARENT, 1f);
+				qrCodeParams = new LinearLayout.LayoutParams(0, MATCH_PARENT, 1f);
+			} else {
+				statusParams = new LinearLayout.LayoutParams(MATCH_PARENT, 0, 1f);
+				qrCodeParams = new LinearLayout.LayoutParams(MATCH_PARENT, 0, 1f);
+			}
+		}
+		statusView.setLayoutParams(statusParams);
+		qrCodeView.setLayoutParams(qrCodeParams);
+		cameraOverlay.invalidate();
+	}
+
+	@Override
+	public void onStop() {
+		super.onStop();
+		stopListening();
+		try {
+			cameraView.stop();
+		} catch (CameraException e) {
+			logCameraExceptionAndFinish(e);
+		}
+	}
+
+	@UiThread
+	private void logCameraExceptionAndFinish(CameraException e) {
+		logException(LOG, WARNING, e);
+		Toast.makeText(getActivity(), R.string.camera_error,
+				LENGTH_LONG).show();
+		finish();
+	}
+
+	@UiThread
+	private void startListening() {
+		KeyAgreementTask oldTask = task;
+		KeyAgreementTask newTask = keyAgreementTaskProvider.get();
+		task = newTask;
+		ioExecutor.execute(() -> {
+			if (oldTask != null) oldTask.stopListening();
+			newTask.listen();
+		});
+	}
+
+	@UiThread
+	private void stopListening() {
+		KeyAgreementTask oldTask = task;
+		ioExecutor.execute(() -> {
+			if (oldTask != null) oldTask.stopListening();
+		});
+	}
+
+	@UiThread
+	private void reset() {
+		// If we've stopped the camera view, restart it
+		if (gotRemotePayload) {
+			try {
+				cameraView.start();
+			} catch (CameraException e) {
+				logCameraExceptionAndFinish(e);
+				return;
+			}
+		}
+		statusView.setVisibility(INVISIBLE);
+		cameraView.setVisibility(VISIBLE);
+		gotRemotePayload = false;
+		gotLocalPayload = false;
+		startListening();
+	}
+
+	@UiThread
+	private void qrCodeScanned(String content) {
+		try {
+			byte[] payloadBytes = content.getBytes(ISO_8859_1);
+			if (LOG.isLoggable(INFO))
+				LOG.info("Remote payload is " + payloadBytes.length + " bytes");
+			Payload remotePayload = payloadParser.parse(payloadBytes);
+			gotRemotePayload = true;
+			cameraView.stop();
+			cameraView.setVisibility(INVISIBLE);
+			statusView.setVisibility(VISIBLE);
+			status.setText(R.string.connecting_to_device);
+			task.connectAndRunProtocol(remotePayload);
+		} catch (UnsupportedVersionException e) {
+			reset();
+			String msg;
+			if (e.isTooOld()) {
+				msg = getString(R.string.qr_code_too_old,
+						getString(R.string.app_name));
+			} else {
+				msg = getString(R.string.qr_code_too_new,
+						getString(R.string.app_name));
+			}
+			showNextFragment(ContactExchangeErrorFragment.newInstance(msg));
+		} catch (CameraException e) {
+			logCameraExceptionAndFinish(e);
+		} catch (IOException | IllegalArgumentException e) {
+			LOG.log(WARNING, "QR Code Invalid", e);
+			reset();
+			Toast.makeText(getActivity(), R.string.qr_code_invalid,
+					LENGTH_LONG).show();
+		}
+	}
+
+	@Override
+	public void eventOccurred(Event e) {
+		if (e instanceof KeyAgreementListeningEvent) {
+			KeyAgreementListeningEvent event = (KeyAgreementListeningEvent) e;
+			gotLocalPayload = true;
+			setQrCode(event.getLocalPayload());
+		} else if (e instanceof KeyAgreementFailedEvent) {
+			keyAgreementFailed();
+		} else if (e instanceof KeyAgreementWaitingEvent) {
+			keyAgreementWaiting();
+		} else if (e instanceof KeyAgreementStartedEvent) {
+			keyAgreementStarted();
+		} else if (e instanceof KeyAgreementAbortedEvent) {
+			KeyAgreementAbortedEvent event = (KeyAgreementAbortedEvent) e;
+			keyAgreementAborted(event.didRemoteAbort());
+		} else if (e instanceof KeyAgreementFinishedEvent) {
+			keyAgreementFinished(((KeyAgreementFinishedEvent) e).getResult());
+		}
+	}
+
+	@UiThread
+	private void keyAgreementFailed() {
+		reset();
+		listener.keyAgreementFailed();
+	}
+
+	@UiThread
+	private void keyAgreementWaiting() {
+		status.setText(listener.keyAgreementWaiting());
+	}
+
+	@UiThread
+	private void keyAgreementStarted() {
+		qrCodeView.setVisibility(INVISIBLE);
+		statusView.setVisibility(VISIBLE);
+		status.setText(listener.keyAgreementStarted());
+	}
+
+	@UiThread
+	private void keyAgreementAborted(boolean remoteAborted) {
+		reset();
+		listener.keyAgreementAborted(remoteAborted);
+	}
+
+	@UiThread
+	private void keyAgreementFinished(KeyAgreementResult result) {
+		statusView.setVisibility(VISIBLE);
+		status.setText(listener.keyAgreementFinished(result));
+	}
+
+	private void setQrCode(Payload localPayload) {
+		Context context = getContext();
+		if (context == null) return;
+		DisplayMetrics dm = context.getResources().getDisplayMetrics();
+		ioExecutor.execute(() -> {
+			byte[] payloadBytes = payloadEncoder.encode(localPayload);
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Local payload is " + payloadBytes.length
+						+ " bytes");
+			}
+			// Use ISO 8859-1 to encode bytes directly as a string
+			String content = new String(payloadBytes, ISO_8859_1);
+			Bitmap qrCode = QrCodeUtils.createQrCode(dm, content);
+			runOnUiThreadUnlessDestroyed(() -> qrCodeView.setQrCode(qrCode));
+		});
+	}
+
+	@Override
+	public void handleResult(Result result) {
+		runOnUiThreadUnlessDestroyed(() -> {
+			LOG.info("Got result from decoder");
+			// Ignore results until the KeyAgreementTask is ready
+			if (!gotLocalPayload) return;
+			if (!gotRemotePayload) qrCodeScanned(result.getText());
+		});
+	}
+
+	@Override
+	protected void finish() {
+		getActivity().getSupportFragmentManager().popBackStack();
+	}
+
+	@NotNullByDefault
+	interface ShardQrCodeEventListener {
+
+		@UiThread
+		void keyAgreementFailed();
+
+		// Should return a string to be displayed as status.
+		@UiThread
+		@Nullable
+		String keyAgreementWaiting();
+
+		// Should return a string to be displayed as status.
+		@UiThread
+		@Nullable
+		String keyAgreementStarted();
+
+		// Will show an error fragment.
+		@UiThread
+		void keyAgreementAborted(boolean remoteAborted);
+
+		// Should return a string to be displayed as status.
+		@UiThread
+		@Nullable
+		String keyAgreementFinished(KeyAgreementResult result);
+	}
+}