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.

.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>

bramble-android/build.gradle

@@ -11,8 +11,8 @@ android {
 	defaultConfig {
 		minSdkVersion 16
 		targetSdkVersion 29
-		versionCode 10214
-		versionName "1.2.14"
+		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/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/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/build.gradle

@@ -22,9 +22,9 @@ android {
 	defaultConfig {
 		minSdkVersion 16
 		targetSdkVersion 29
-		versionCode 10214
-		versionName "1.2.14"
-		applicationId "org.briarproject.briar.android"
+		versionCode 10216
+		versionName "1.2.16"
+		applicationId "org.briarproject.briar.socialbackup"
 
 		vectorDrawables.useSupportLibrary = true
 		buildConfigField "String", "GitHash",
@@ -101,6 +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'
@@ -136,6 +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/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

@@ -52,6 +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;
@@ -396,6 +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);
 		}

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/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/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

@@ -68,6 +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;
@@ -297,6 +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

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

@@ -79,9 +79,10 @@ public class GroupActivity extends
 
 		// start with group disabled and enable when not dissolved
 		setGroupEnabled(false);
-		viewModel.isDissolved().observeEvent(this, dissolved -> {
+		viewModel.isDissolved().observe(this, dissolved -> {
 			setGroupEnabled(!dissolved);
-			if (dissolved) onGroupDissolved();
+			// only show dialog when no prior state
+			if (dissolved && state == null) onGroupDissolved();
 		});
 	}
 
@@ -153,7 +154,7 @@ public class GroupActivity extends
 
 	@Override
 	public void onReplyClick(GroupMessageItem item) {
-		Boolean isDissolved = viewModel.isDissolved().getLastValue();
+		Boolean isDissolved = viewModel.isDissolved().getValue();
 		if (isDissolved != null && !isDissolved) super.onReplyClick(item);
 	}
 

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

@@ -22,8 +22,6 @@ import org.briarproject.bramble.api.system.AndroidExecutor;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.briar.android.sharing.SharingController;
 import org.briarproject.briar.android.threaded.ThreadListViewModel;
-import org.briarproject.briar.android.viewmodel.LiveEvent;
-import org.briarproject.briar.android.viewmodel.MutableLiveEvent;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
 import org.briarproject.briar.api.client.MessageTracker;
 import org.briarproject.briar.api.client.MessageTracker.GroupCount;
@@ -71,8 +69,8 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 	private final MutableLiveData<PrivateGroup> privateGroup =
 			new MutableLiveData<>();
 	private final MutableLiveData<Boolean> isCreator = new MutableLiveData<>();
-	private final MutableLiveEvent<Boolean> isDissolved =
-			new MutableLiveEvent<>();
+	private final MutableLiveData<Boolean> isDissolved =
+			new MutableLiveData<>();
 
 	@Inject
 	GroupViewModel(Application application,
@@ -129,7 +127,7 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 		} else if (e instanceof GroupDissolvedEvent) {
 			GroupDissolvedEvent g = (GroupDissolvedEvent) e;
 			if (g.getGroupId().equals(groupId)) {
-				isDissolved.setEvent(true);
+				isDissolved.setValue(true);
 			}
 		} else {
 			super.eventOccurred(e);
@@ -164,7 +162,7 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 		loadList(txn -> {
 			// check first if group is dissolved
 			isDissolved
-					.postEvent(privateGroupManager.isDissolved(txn, groupId));
+					.postValue(privateGroupManager.isDissolved(txn, groupId));
 			// now continue to load the items
 			long start = now();
 			List<GroupMessageHeader> headers =
@@ -282,7 +280,7 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 		return isCreator;
 	}
 
-	LiveEvent<Boolean> isDissolved() {
+	LiveData<Boolean> isDissolved() {
 		return isDissolved;
 	}
 

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/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);
+	}
+}

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

@@ -0,0 +1,70 @@
+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;
+import androidx.annotation.UiThread;
+
+public class ShardsSentFragment extends BaseFragment {
+
+	public static final String TAG = ShardsSentFragment.class.getName();
+
+	interface ShardsSentDismissedListener {
+
+		@UiThread
+		void shardsSentDismissed();
+
+	}
+
+	protected ShardsSentDismissedListener listener;
+
+	@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_shards_sent,
+				container, false);
+
+		Button button = view.findViewById(R.id.button);
+		button.setOnClickListener(e -> {
+			listener.shardsSentDismissed();
+		});
+
+		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/ThresholdDefinedListener.java

@@ -0,0 +1,12 @@
+package org.briarproject.briar.android.socialbackup;
+
+import org.briarproject.bramble.api.db.DbException;
+
+import androidx.annotation.UiThread;
+
+public interface ThresholdDefinedListener {
+
+	@UiThread
+	void thresholdDefined(int threshold) throws DbException;
+
+}

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

@@ -0,0 +1,182 @@
+package org.briarproject.briar.android.socialbackup;
+
+import android.content.Context;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.SeekBar;
+import android.widget.TextView;
+
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.fragment.BaseFragment;
+import org.magmacollective.darkcrystal.secretsharingwrapper.SecretSharingWrapper;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+public class ThresholdSelectorFragment extends BaseFragment {
+
+	public static final String TAG = ThresholdSelectorFragment.class.getName();
+	private static final String NUMBER_CUSTODIANS = "numberCustodians";
+
+	protected ThresholdDefinedListener listener;
+
+	private int numberOfCustodians;
+	private int threshold;
+	private int recommendedThreshold;
+	private SeekBar seekBar;
+	private TextView thresholdRepresentation;
+	private TextView message;
+	private TextView mOfn;
+
+	public static ThresholdSelectorFragment newInstance(int numberCustodians) {
+		Bundle bundle = new Bundle();
+		bundle.putInt(NUMBER_CUSTODIANS, numberCustodians);
+		ThresholdSelectorFragment fragment = new ThresholdSelectorFragment();
+		fragment.setArguments(bundle);
+		return fragment;
+	}
+
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		requireActivity().setTitle(R.string.title_define_threshold);
+	}
+
+	@Nullable
+	@Override
+	public View onCreateView(@NonNull LayoutInflater inflater,
+			@Nullable ViewGroup container,
+			@Nullable Bundle savedInstanceState) {
+		View view = inflater.inflate(R.layout.fragment_select_threshold,
+				container, false);
+		Bundle args = requireArguments();
+		numberOfCustodians = args.getInt(NUMBER_CUSTODIANS);
+		seekBar = view.findViewById(R.id.seekBar);
+		thresholdRepresentation =
+				view.findViewById(R.id.textViewThresholdRepresentation);
+		message = view.findViewById(R.id.textViewMessage);
+		mOfn = view.findViewById(R.id.textViewmOfn);
+
+		if (numberOfCustodians == 2) {
+			message.setText(R.string.threshold_too_few_custodians);
+		}
+		if (numberOfCustodians > 3) {
+			seekBar.setMax(numberOfCustodians -3);
+			seekBar.setProgress(threshold - 2);
+			seekBar.setOnSeekBarChangeListener(new SeekBarListener());
+			recommendedThreshold =
+					SecretSharingWrapper.defaultThreshold(numberOfCustodians);
+			threshold = recommendedThreshold;
+
+		} else {
+			seekBar.setEnabled(false);
+			threshold = 2;
+			seekBar.setMax(numberOfCustodians);
+			seekBar.setProgress(threshold);
+			TextView t = view.findViewById(R.id.title_threshold);
+			t.setText(R.string.threshold_disabled);
+		}
+		thresholdRepresentation.setText(buildThresholdRepresentationString());
+		setmOfnText();
+		return view;
+//        return super.onCreateView(inflater, container, savedInstanceState);
+	}
+
+	private void setmOfnText() {
+		mOfn.setText(String.format(
+				getString(R.string.threshold_m_of_n), threshold,
+				numberOfCustodians));
+	}
+
+	@Override
+	public void onAttach(Context context) {
+		super.onAttach(context);
+		listener = (ThresholdDefinedListener) context;
+	}
+
+
+	@Override
+	public String getUniqueTag() {
+		return TAG;
+	}
+
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+	}
+
+	@Override
+	public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
+		inflater.inflate(R.menu.define_threshold_actions, menu);
+		super.onCreateOptionsMenu(menu, inflater);
+	}
+
+	@Override
+	public boolean onOptionsItemSelected(MenuItem item) {
+		switch (item.getItemId()) {
+			case R.id.action_threshold_defined:
+				try {
+					listener.thresholdDefined(threshold);
+				} catch (DbException e) {
+					e.printStackTrace();
+				}
+				return true;
+			default:
+				return super.onOptionsItemSelected(item);
+		}
+	}
+
+	private String buildThresholdRepresentationString() {
+		String thresholdRepresentationText = "";
+		for (int i = 0; i < threshold; i++) {
+			thresholdRepresentationText += getString(R.string.filled_bullet);
+		}
+		for (int i = 0; i < (numberOfCustodians - threshold); i++) {
+			thresholdRepresentationText += getString(R.string.linear_bullet);
+		}
+		return thresholdRepresentationText;
+	}
+
+	private class SeekBarListener implements SeekBar.OnSeekBarChangeListener {
+
+		@Override
+		public void onProgressChanged(SeekBar seekBar, int progress,
+				boolean fromUser) {
+			threshold = progress + 2;
+
+			thresholdRepresentation.setText(
+					buildThresholdRepresentationString()
+			);
+			setmOfnText();
+
+			int sanityLevel = SecretSharingWrapper
+					.thresholdSanity(threshold, numberOfCustodians);
+			int text = R.string.threshold_secure;
+			if (threshold == recommendedThreshold)
+				text = R.string.threshold_recommended;
+			if (sanityLevel < -1) text = R.string.threshold_low_insecure;
+			if (sanityLevel > 0) text = R.string.threshold_high_insecure;
+			message.setText(text);
+			// TODO change colour of thresholdRepresentation to green/red based on sanityLevel
+		}
+
+		@Override
+		public void onStartTrackingTouch(SeekBar seekBar) {
+			// do nothing
+		}
+
+		@Override
+		public void onStopTrackingTouch(SeekBar seekBar) {
+			// do nothing
+		}
+
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/creation/CreateBackupController.java

@@ -0,0 +1,26 @@
+package org.briarproject.briar.android.socialbackup.creation;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.briar.android.contactselection.ContactSelectorController;
+import org.briarproject.briar.android.contactselection.SelectableContactItem;
+import org.briarproject.briar.android.controller.handler.ResultExceptionHandler;
+
+import java.util.Collection;
+
+import androidx.annotation.Nullable;
+
+@NotNullByDefault
+public interface CreateBackupController
+		extends ContactSelectorController<SelectableContactItem> {
+
+	void createGroup(String name,
+			ResultExceptionHandler<GroupId, DbException> result);
+
+	void sendInvitation(GroupId g, Collection<ContactId> contacts,
+			@Nullable String text,
+			ResultExceptionHandler<Void, DbException> result);
+
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/creation/CreateBackupControllerImpl.java

@@ -0,0 +1,206 @@
+package org.briarproject.briar.android.socialbackup.creation;
+
+import org.briarproject.bramble.api.contact.Contact;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.ContactManager;
+import org.briarproject.bramble.api.crypto.CryptoExecutor;
+import org.briarproject.bramble.api.db.DatabaseExecutor;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.NoSuchContactException;
+import org.briarproject.bramble.api.identity.IdentityManager;
+import org.briarproject.bramble.api.identity.LocalAuthor;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.briar.android.contactselection.ContactSelectorControllerImpl;
+import org.briarproject.briar.android.controller.handler.ResultExceptionHandler;
+import org.briarproject.briar.api.identity.AuthorManager;
+import org.briarproject.briar.api.privategroup.GroupMessage;
+import org.briarproject.briar.api.privategroup.GroupMessageFactory;
+import org.briarproject.briar.api.privategroup.PrivateGroup;
+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 java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
+
+import androidx.annotation.Nullable;
+
+import static java.util.logging.Level.WARNING;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+@Immutable
+@NotNullByDefault
+/**
+ * Derived from {@link org.briarproject.briar.android.privategroup.invitation.GroupInvitationControllerImpl}
+ */
+class CreateBackupControllerImpl extends ContactSelectorControllerImpl
+		implements CreateBackupController {
+
+	private static final Logger LOG =
+			Logger.getLogger(
+					CreateBackupControllerImpl.class.getName());
+
+	private final Executor cryptoExecutor;
+	private final ContactManager contactManager;
+	private final IdentityManager identityManager;
+	private final PrivateGroupFactory groupFactory;
+	private final GroupMessageFactory groupMessageFactory;
+	private final PrivateGroupManager groupManager;
+	private final GroupInvitationFactory groupInvitationFactory;
+	private final GroupInvitationManager groupInvitationManager;
+	private final Clock clock;
+
+	@Inject
+	CreateBackupControllerImpl(@DatabaseExecutor Executor dbExecutor,
+			@CryptoExecutor Executor cryptoExecutor,
+			LifecycleManager lifecycleManager, ContactManager contactManager,
+			IdentityManager identityManager, PrivateGroupFactory groupFactory,
+			GroupMessageFactory groupMessageFactory,
+			PrivateGroupManager groupManager,
+			GroupInvitationFactory groupInvitationFactory,
+			GroupInvitationManager groupInvitationManager, Clock clock, AuthorManager authorManager) {
+		super(dbExecutor, lifecycleManager, contactManager, authorManager);
+		this.cryptoExecutor = cryptoExecutor;
+		this.contactManager = contactManager;
+		this.identityManager = identityManager;
+		this.groupFactory = groupFactory;
+		this.groupMessageFactory = groupMessageFactory;
+		this.groupManager = groupManager;
+		this.groupInvitationFactory = groupInvitationFactory;
+		this.groupInvitationManager = groupInvitationManager;
+		this.clock = clock;
+	}
+
+	@Override
+	public void createGroup(String name,
+			ResultExceptionHandler<GroupId, DbException> handler) {
+		runOnDbThread(() -> {
+			try {
+				LocalAuthor author = identityManager.getLocalAuthor();
+				createGroupAndMessages(author, name, handler);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+				handler.onException(e);
+			}
+		});
+	}
+
+	private void createGroupAndMessages(LocalAuthor author, String name,
+			ResultExceptionHandler<GroupId, DbException> handler) {
+		cryptoExecutor.execute(() -> {
+			LOG.info("Creating group...");
+			PrivateGroup group =
+					groupFactory.createPrivateGroup(name, author);
+			LOG.info("Creating new join announcement...");
+			GroupMessage joinMsg =
+					groupMessageFactory.createJoinMessage(group.getId(),
+							clock.currentTimeMillis(), author);
+			storeGroup(group, joinMsg, handler);
+		});
+	}
+
+	private void storeGroup(PrivateGroup group, GroupMessage joinMsg,
+			ResultExceptionHandler<GroupId, DbException> handler) {
+		runOnDbThread(() -> {
+			LOG.info("Adding group to database...");
+			try {
+				groupManager.addPrivateGroup(group, joinMsg, true);
+				handler.onResult(group.getId());
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+				handler.onException(e);
+			}
+		});
+	}
+
+	@Override
+	protected boolean isDisabled(GroupId g, Contact c) {
+		return false;
+	}
+
+	@Override
+	public void sendInvitation(GroupId g, Collection<ContactId> contactIds,
+			@Nullable String text,
+			ResultExceptionHandler<Void, DbException> handler) {
+		runOnDbThread(() -> {
+			try {
+				LocalAuthor localAuthor = identityManager.getLocalAuthor();
+				List<Contact> contacts = new ArrayList<>();
+				for (ContactId c : contactIds) {
+					try {
+						contacts.add(contactManager.getContact(c));
+					} catch (NoSuchContactException e) {
+						// Continue
+					}
+				}
+				signInvitations(g, localAuthor, contacts, text, handler);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+				handler.onException(e);
+			}
+		});
+	}
+
+	private void signInvitations(GroupId g, LocalAuthor localAuthor,
+			Collection<Contact> contacts, @Nullable String text,
+			ResultExceptionHandler<Void, DbException> handler) {
+		cryptoExecutor.execute(() -> {
+			long timestamp = clock.currentTimeMillis();
+			List<InvitationContext> contexts = new ArrayList<>();
+			for (Contact c : contacts) {
+				byte[] signature = groupInvitationFactory.signInvitation(c, g,
+						timestamp, localAuthor.getPrivateKey());
+				contexts.add(new InvitationContext(c.getId(), timestamp,
+						signature));
+			}
+			sendInvitations(g, contexts, text, handler);
+		});
+	}
+
+	private void sendInvitations(GroupId g,
+			Collection<InvitationContext> contexts, @Nullable String text,
+			ResultExceptionHandler<Void, DbException> handler) {
+		runOnDbThread(() -> {
+			try {
+				for (InvitationContext context : contexts) {
+					try {
+						groupInvitationManager.sendInvitation(g,
+								context.contactId, text, context.timestamp,
+								context.signature);
+					} catch (NoSuchContactException e) {
+						// Continue
+					}
+				}
+				//noinspection ConstantConditions
+				handler.onResult(null);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+				handler.onException(e);
+			}
+		});
+	}
+
+	private static class InvitationContext {
+
+		private final ContactId contactId;
+		private final long timestamp;
+		private final byte[] signature;
+
+		private InvitationContext(ContactId contactId, long timestamp,
+				byte[] signature) {
+			this.contactId = contactId;
+			this.timestamp = timestamp;
+			this.signature = signature;
+		}
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/socialbackup/creation/CreateBackupModule.java

@@ -0,0 +1,18 @@
+package org.briarproject.briar.android.socialbackup.creation;
+
+import org.briarproject.briar.android.activity.ActivityScope;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class CreateBackupModule {
+
+	@ActivityScope
+	@Provides
+	CreateBackupController provideCreateGroupController(
+			CreateBackupControllerImpl createBackupController) {
+		return createBackupController;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/splash/ExpiredActivity.java

@@ -1,5 +1,6 @@
 package org.briarproject.briar.android.splash;
 
+import android.content.Context;
 import android.content.Intent;
 import android.net.Uri;
 import android.os.Bundle;
@@ -7,6 +8,7 @@ import android.view.View;
 import android.view.View.OnClickListener;
 
 import org.briarproject.briar.R;
+import org.briarproject.briar.android.Localizer;
 
 import androidx.appcompat.app.AppCompatActivity;
 
@@ -27,6 +29,13 @@ public class ExpiredActivity extends AppCompatActivity
 		findViewById(R.id.download_briar_button).setOnClickListener(this);
 	}
 
+	@Override
+	protected void attachBaseContext(Context base) {
+		super.attachBaseContext(
+				Localizer.getInstance().setLocale(base));
+		Localizer.getInstance().setLocale(this);
+	}
+
 	@Override
 	public void onClick(View v) {
 		Uri uri = Uri.parse("https://briarproject.org/download.html");

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

@@ -197,6 +197,10 @@ public abstract class ThreadListViewModel<I extends ThreadItem>
 	 */
 	@UiThread
 	protected void addItem(I item, boolean scrollToItem) {
+		// If items haven't loaded, we need to wait until they have.
+		// Since this was a R/W DB transaction, the load will pick up this item.
+		if (items.getValue() == null) return;
+
 		messageTree.add(item);
 		if (scrollToItem) this.scrollToItem.set(item.getId());
 		items.setValue(new LiveResult<>(messageTree.depthFirstOrder()));

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

@@ -97,6 +97,7 @@ import static java.util.concurrent.TimeUnit.DAYS;
 import static org.briarproject.bramble.util.AndroidUtils.getSupportedImageContentTypes;
 import static org.briarproject.briar.BuildConfig.APPLICATION_ID;
 import static org.briarproject.briar.android.TestingConstants.EXPIRY_DATE;
+import static org.briarproject.briar.android.reporting.CrashReportActivity.EXTRA_APP_LOGCAT;
 import static org.briarproject.briar.android.reporting.CrashReportActivity.EXTRA_APP_START_TIME;
 import static org.briarproject.briar.android.reporting.CrashReportActivity.EXTRA_THROWABLE;
 
@@ -357,16 +358,17 @@ public class UiUtils {
 	}
 
 	public static void triggerFeedback(Context ctx) {
-		startDevReportActivity(ctx, FeedbackActivity.class, null, null);
+		startDevReportActivity(ctx, FeedbackActivity.class, null, null, null);
 	}
 
 	public static void startDevReportActivity(Context ctx,
 			Class<? extends FragmentActivity> activity, @Nullable Throwable t,
-			@Nullable Long appStartTime) {
+			@Nullable Long appStartTime, @Nullable byte[] logKey) {
 		final Intent dialogIntent = new Intent(ctx, activity);
 		dialogIntent.setFlags(FLAG_ACTIVITY_NEW_TASK);
 		dialogIntent.putExtra(EXTRA_THROWABLE, t);
 		dialogIntent.putExtra(EXTRA_APP_START_TIME, appStartTime);
+		dialogIntent.putExtra(EXTRA_APP_LOGCAT, logKey);
 		ctx.startActivity(dialogIntent);
 	}
 

briar-android/src/main/java/org/briarproject/briar/api/android/AndroidNotificationManager.java

@@ -39,7 +39,8 @@ public interface AndroidNotificationManager {
 	String BLOG_CHANNEL_ID = "blogs";
 	// Channels are sorted by channel ID in the Settings app, so use IDs
 	// that will sort below the main channels such as contacts
-	String ONGOING_CHANNEL_ID = "zForegroundService";
+	String ONGOING_CHANNEL_OLD_ID = "zForegroundService";
+	String ONGOING_CHANNEL_ID = "zForegroundService2";
 	String FAILURE_CHANNEL_ID = "zStartupFailure";
 	String REMINDER_CHANNEL_ID = "zSignInReminder";
 

briar-android/src/main/java/org/briarproject/briar/api/android/LockManager.java

@@ -8,6 +8,7 @@ import androidx.lifecycle.LiveData;
 public interface LockManager {
 
 	String ACTION_LOCK = "lock";
+	String EXTRA_PID = "PID";
 
 	/**
 	 * Stops the inactivity timer when the user interacts with the app.

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

@@ -0,0 +1,16 @@
+package org.briarproject.briar.socialbackup;
+
+import org.briarproject.briar.android.socialbackup.DarkCrystalImpl;
+import org.briarproject.briar.api.socialbackup.DarkCrystal;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class AndroidDarkCrystalModule {
+
+	@Provides
+	DarkCrystal darkCrystal(DarkCrystalImpl darkCrystal) {
+		return darkCrystal;
+	}
+}

briar-android/src/main/res/drawable/ic_baseline_done_outline_24.xml

@@ -0,0 +1,5 @@
+<vector android:height="24dp" android:tint="#29C400"
+    android:viewportHeight="24" android:viewportWidth="24"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="@android:color/white" android:pathData="M19.77,5.03l1.4,1.4L8.43,19.17l-5.6,-5.6 1.4,-1.4 4.2,4.2L19.77,5.03m0,-2.83L8.43,13.54l-4.2,-4.2L0,13.57 8.43,22 24,6.43 19.77,2.2z"/>
+</vector>