Disable image attachments and profile pictures for user testing.

Fix bomb icon color in incoming image messages without text

See merge request briar/briar!1358

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

@@ -1,6 +1,7 @@
 package org.briarproject.bramble.api.client;
 
 import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.crypto.PrivateKey;
 import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.data.BdfDictionary;
@@ -119,4 +120,17 @@ public interface ClientHelper {
 	Map<TransportId, TransportProperties> parseAndValidateTransportPropertiesMap(
 			BdfDictionary properties) throws FormatException;
 
+	/**
+	 * Retrieves the contact ID from the group metadata of the given contact
+	 * group.
+	 */
+	ContactId getContactId(Transaction txn, GroupId contactGroupId)
+		throws DbException, FormatException;
+
+	/**
+	 * Stores the given contact ID in the group metadata of the given contact
+	 * group.
+	 */
+	void setContactId(Transaction txn, GroupId contactGroupId, ContactId c)
+		throws DbException;
 }

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

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

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

@@ -6,7 +6,9 @@ import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import javax.annotation.Nullable;
+import javax.annotation.concurrent.Immutable;
 
+@Immutable
 @NotNullByDefault
 public class ValidationUtils {
 
@@ -64,4 +66,9 @@ public class ValidationUtils {
 		if (dictionary != null && dictionary.size() != size)
 			throw new FormatException();
 	}
+
+	public static void checkRange(@Nullable Long l, long min, long max)
+			throws FormatException {
+		if (l != null && (l < min || l > max)) throw new FormatException();
+	}
 }

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

@@ -0,0 +1,8 @@
+package org.briarproject.bramble.test;
+
+public interface TimeTravel {
+
+	void setCurrentTimeMillis(long now) throws InterruptedException;
+
+	void addCurrentTimeMillis(long add) throws InterruptedException;
+}

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

@@ -21,7 +21,6 @@ import org.briarproject.bramble.rendezvous.RendezvousModule;
 import org.briarproject.bramble.settings.SettingsModule;
 import org.briarproject.bramble.sync.SyncModule;
 import org.briarproject.bramble.sync.validation.ValidationModule;
-import org.briarproject.bramble.system.ClockModule;
 import org.briarproject.bramble.transport.TransportModule;
 import org.briarproject.bramble.versioning.VersioningModule;
 
@@ -29,7 +28,6 @@ import dagger.Module;
 
 @Module(includes = {
 		ClientModule.class,
-		ClockModule.class,
 		ConnectionModule.class,
 		ContactModule.class,
 		CryptoModule.class,

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

@@ -2,11 +2,13 @@ package org.briarproject.bramble.client;
 
 import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.api.client.ClientHelper;
+import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.KeyParser;
 import org.briarproject.bramble.api.crypto.PrivateKey;
 import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.data.BdfDictionary;
+import org.briarproject.bramble.api.data.BdfEntry;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.data.BdfReader;
 import org.briarproject.bramble.api.data.BdfReaderFactory;
@@ -39,6 +41,7 @@ import java.util.Map.Entry;
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
+import static org.briarproject.bramble.api.client.ContactGroupConstants.GROUP_KEY_CONTACT_ID;
 import static org.briarproject.bramble.api.identity.Author.FORMAT_VERSION;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
@@ -389,4 +392,27 @@ class ClientHelperImpl implements ClientHelper {
 		return tpMap;
 	}
 
+	@Override
+	public ContactId getContactId(Transaction txn, GroupId contactGroupId)
+			throws DbException {
+		try {
+			BdfDictionary meta =
+					getGroupMetadataAsDictionary(txn, contactGroupId);
+			return new ContactId(meta.getLong(GROUP_KEY_CONTACT_ID).intValue());
+		} catch (FormatException e) {
+			throw new DbException(e); // Invalid group metadata
+		}
+	}
+
+	@Override
+	public void setContactId(Transaction txn, GroupId contactGroupId,
+			ContactId c) throws DbException {
+		BdfDictionary meta = BdfDictionary.of(
+				new BdfEntry(GROUP_KEY_CONTACT_ID, c.getInt()));
+		try {
+			mergeGroupMetadata(txn, contactGroupId, meta);
+		} catch (FormatException e) {
+			throw new AssertionError(e);
+		}
+	}
 }

bramble-core/src/main/java/org/briarproject/bramble/versioning/ClientVersioningConstants.java

@@ -5,6 +5,5 @@ interface ClientVersioningConstants {
 	// Metadata keys
 	String MSG_KEY_UPDATE_VERSION = "version";
 	String MSG_KEY_LOCAL = "local";
-	String GROUP_KEY_CONTACT_ID = "contactId";
 }
 

bramble-core/src/main/java/org/briarproject/bramble/versioning/ClientVersioningManagerImpl.java

@@ -50,7 +50,6 @@ import static java.util.Collections.emptyList;
 import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
 import static org.briarproject.bramble.api.sync.Group.Visibility.VISIBLE;
-import static org.briarproject.bramble.versioning.ClientVersioningConstants.GROUP_KEY_CONTACT_ID;
 import static org.briarproject.bramble.versioning.ClientVersioningConstants.MSG_KEY_LOCAL;
 import static org.briarproject.bramble.versioning.ClientVersioningConstants.MSG_KEY_UPDATE_VERSION;
 
@@ -161,13 +160,7 @@ class ClientVersioningManagerImpl implements ClientVersioningManager,
 		db.addGroup(txn, g);
 		db.setGroupVisibility(txn, c.getId(), g.getId(), SHARED);
 		// Attach the contact ID to the group
-		BdfDictionary meta = new BdfDictionary();
-		meta.put(GROUP_KEY_CONTACT_ID, c.getId().getInt());
-		try {
-			clientHelper.mergeGroupMetadata(txn, g.getId(), meta);
-		} catch (FormatException e) {
-			throw new AssertionError(e);
-		}
+		clientHelper.setContactId(txn, g.getId(), c.getId());
 		// Create and store the first local update
 		List<ClientVersion> versions = new ArrayList<>(clients);
 		Collections.sort(versions);
@@ -229,7 +222,7 @@ class ClientVersioningManagerImpl implements ClientVersioningManager,
 			Map<ClientMajorVersion, Visibility> after =
 					getVisibilities(newLocalStates, newRemoteStates);
 			// Call hooks for any visibilities that have changed
-			ContactId c = getContactId(txn, m.getGroupId());
+			ContactId c = clientHelper.getContactId(txn, m.getGroupId());
 			if (!before.equals(after)) {
 				Contact contact = db.getContact(txn, c);
 				callVisibilityHooks(txn, contact, before, after);
@@ -521,17 +514,6 @@ class ClientVersioningManagerImpl implements ClientVersioningManager,
 		storeUpdate(txn, g, states, 1);
 	}
 
-	private ContactId getContactId(Transaction txn, GroupId g)
-			throws DbException {
-		try {
-			BdfDictionary meta =
-					clientHelper.getGroupMetadataAsDictionary(txn, g);
-			return new ContactId(meta.getLong(GROUP_KEY_CONTACT_ID).intValue());
-		} catch (FormatException e) {
-			throw new DbException(e);
-		}
-	}
-
 	private List<ClientState> updateStatesFromRemoteStates(
 			List<ClientState> oldLocalStates, List<ClientState> remoteStates) {
 		Set<ClientMajorVersion> remoteSet = new HashSet<>();

bramble-core/src/test/java/org/briarproject/bramble/BrambleCoreIntegrationTestEagerSingletons.java

@@ -1,18 +1,18 @@
 package org.briarproject.bramble;
 
-import org.briarproject.bramble.system.DefaultTaskSchedulerModule;
+import org.briarproject.bramble.system.TimeTravelModule;
 
 public interface BrambleCoreIntegrationTestEagerSingletons
 		extends BrambleCoreEagerSingletons {
 
-	void inject(DefaultTaskSchedulerModule.EagerSingletons init);
+	void inject(TimeTravelModule.EagerSingletons init);
 
 	class Helper {
 
 		public static void injectEagerSingletons(
 				BrambleCoreIntegrationTestEagerSingletons c) {
 			BrambleCoreEagerSingletons.Helper.injectEagerSingletons(c);
-			c.inject(new DefaultTaskSchedulerModule.EagerSingletons());
+			c.inject(new TimeTravelModule.EagerSingletons());
 		}
 	}
 }

bramble-core/src/test/java/org/briarproject/bramble/system/TestTaskScheduler.java

@@ -0,0 +1,122 @@
+package org.briarproject.bramble.system;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.system.TaskScheduler;
+
+import java.util.Queue;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Executor;
+import java.util.concurrent.PriorityBlockingQueue;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static java.util.concurrent.TimeUnit.MINUTES;
+import static org.junit.Assert.fail;
+
+/**
+ * A {@link TaskScheduler} for use in tests. The scheduler keeps all scheduled
+ * tasks in a queue until {@link #runTasks()} is called.
+ */
+@NotNullByDefault
+class TestTaskScheduler implements TaskScheduler {
+
+	private final Queue<Task> queue = new PriorityBlockingQueue<>();
+	private final Clock clock;
+
+	TestTaskScheduler(Clock clock) {
+		this.clock = clock;
+	}
+
+	@Override
+	public Cancellable schedule(Runnable task, Executor executor, long delay,
+			TimeUnit unit) {
+		AtomicBoolean cancelled = new AtomicBoolean(false);
+		return schedule(task, executor, delay, unit, cancelled);
+	}
+
+	@Override
+	public Cancellable scheduleWithFixedDelay(Runnable task, Executor executor,
+			long delay, long interval, TimeUnit unit) {
+		AtomicBoolean cancelled = new AtomicBoolean(false);
+		return scheduleWithFixedDelay(task, executor, delay, interval, unit,
+				cancelled);
+	}
+
+	private Cancellable schedule(Runnable task, Executor executor, long delay,
+			TimeUnit unit, AtomicBoolean cancelled) {
+		long delayMillis = MILLISECONDS.convert(delay, unit);
+		long dueMillis = clock.currentTimeMillis() + delayMillis;
+		Task t = new Task(task, executor, dueMillis, cancelled);
+		queue.add(t);
+		return t;
+	}
+
+	private Cancellable scheduleWithFixedDelay(Runnable task, Executor executor,
+			long delay, long interval, TimeUnit unit, AtomicBoolean cancelled) {
+		// All executions of this periodic task share a cancelled flag
+		Runnable wrapped = () -> {
+			task.run();
+			scheduleWithFixedDelay(task, executor, interval, interval, unit,
+					cancelled);
+		};
+		return schedule(wrapped, executor, delay, unit, cancelled);
+	}
+
+	/**
+	 * Runs any scheduled tasks that are due.
+	 */
+	void runTasks() throws InterruptedException {
+		long now = clock.currentTimeMillis();
+		while (true) {
+			Task t = queue.peek();
+			if (t == null || t.dueMillis > now) return;
+			t = queue.poll();
+			// Submit the task to its executor and wait for it to finish
+			if (!t.run().await(1, MINUTES)) fail();
+		}
+	}
+
+	private static class Task
+			implements Cancellable, Comparable<Task> {
+
+		private final Runnable task;
+		private final Executor executor;
+		private final long dueMillis;
+		private final AtomicBoolean cancelled;
+
+		private Task(Runnable task, Executor executor, long dueMillis,
+				AtomicBoolean cancelled) {
+			this.task = task;
+			this.executor = executor;
+			this.dueMillis = dueMillis;
+			this.cancelled = cancelled;
+		}
+
+		@SuppressWarnings("UseCompareMethod") // Animal Sniffer
+		@Override
+		public int compareTo(Task task) {
+			return Long.valueOf(dueMillis).compareTo(task.dueMillis);
+		}
+
+		/**
+		 * Submits the task to its executor and returns a latch that will be
+		 * released when the task finishes.
+		 */
+		public CountDownLatch run() {
+			if (cancelled.get()) return new CountDownLatch(0);
+			CountDownLatch latch = new CountDownLatch(1);
+			executor.execute(() -> {
+				task.run();
+				latch.countDown();
+			});
+			return latch;
+		}
+
+		@Override
+		public void cancel() {
+			cancelled.set(true);
+		}
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/system/TimeTravelModule.java

@@ -0,0 +1,98 @@
+package org.briarproject.bramble.system;
+
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.test.SettableClock;
+import org.briarproject.bramble.test.TimeTravel;
+
+import java.util.concurrent.RejectedExecutionHandler;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.atomic.AtomicLong;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class TimeTravelModule {
+
+	public static class EagerSingletons {
+		@Inject
+		TaskScheduler scheduler;
+	}
+
+	private final ScheduledExecutorService scheduledExecutorService;
+	private final Clock clock;
+	private final TaskScheduler taskScheduler;
+	private final TimeTravel timeTravel;
+
+	public TimeTravelModule() {
+		this(false);
+	}
+
+	public TimeTravelModule(boolean travel) {
+		// Discard tasks that are submitted during shutdown
+		RejectedExecutionHandler policy =
+				new ScheduledThreadPoolExecutor.DiscardPolicy();
+		scheduledExecutorService =
+				new ScheduledThreadPoolExecutor(1, policy);
+		if (travel) {
+			// Use a SettableClock and TestTaskScheduler to allow time travel
+			AtomicLong time = new AtomicLong(System.currentTimeMillis());
+			clock = new SettableClock(time);
+			TestTaskScheduler testTaskScheduler = new TestTaskScheduler(clock);
+			taskScheduler = testTaskScheduler;
+			timeTravel = new TimeTravel() {
+				@Override
+				public void setCurrentTimeMillis(long now)
+						throws InterruptedException {
+					time.set(now);
+					testTaskScheduler.runTasks();
+				}
+
+				@Override
+				public void addCurrentTimeMillis(long add)
+						throws InterruptedException {
+					time.addAndGet(add);
+					testTaskScheduler.runTasks();
+				}
+			};
+		} else {
+			// Use the default clock and task scheduler
+			clock = new SystemClock();
+			taskScheduler = new TaskSchedulerImpl(scheduledExecutorService);
+			timeTravel = new TimeTravel() {
+				@Override
+				public void setCurrentTimeMillis(long now) {
+					throw new UnsupportedOperationException();
+				}
+
+				@Override
+				public void addCurrentTimeMillis(long add) {
+					throw new UnsupportedOperationException();
+				}
+			};
+		}
+	}
+
+	@Provides
+	Clock provideClock() {
+		return clock;
+	}
+
+	@Provides
+	@Singleton
+	TaskScheduler provideTaskScheduler(LifecycleManager lifecycleManager) {
+		lifecycleManager.registerForShutdown(scheduledExecutorService);
+		return taskScheduler;
+	}
+
+	@Provides
+	TimeTravel provideTimeTravel() {
+		return timeTravel;
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/test/BrambleCoreIntegrationTestModule.java

@@ -3,8 +3,8 @@ package org.briarproject.bramble.test;
 import org.briarproject.bramble.api.FeatureFlags;
 import org.briarproject.bramble.battery.DefaultBatteryManagerModule;
 import org.briarproject.bramble.event.DefaultEventExecutorModule;
-import org.briarproject.bramble.system.DefaultTaskSchedulerModule;
 import org.briarproject.bramble.system.DefaultWakefulIoExecutorModule;
+import org.briarproject.bramble.system.TimeTravelModule;
 
 import dagger.Module;
 import dagger.Provides;
@@ -12,11 +12,11 @@ import dagger.Provides;
 @Module(includes = {
 		DefaultBatteryManagerModule.class,
 		DefaultEventExecutorModule.class,
-		DefaultTaskSchedulerModule.class,
 		DefaultWakefulIoExecutorModule.class,
 		TestDatabaseConfigModule.class,
 		TestPluginConfigModule.class,
-		TestSecureRandomModule.class
+		TestSecureRandomModule.class,
+		TimeTravelModule.class
 })
 public class BrambleCoreIntegrationTestModule {
 

bramble-core/src/test/java/org/briarproject/bramble/versioning/ClientVersioningManagerImplTest.java

@@ -38,7 +38,6 @@ import static org.briarproject.bramble.test.TestUtils.getContact;
 import static org.briarproject.bramble.test.TestUtils.getGroup;
 import static org.briarproject.bramble.test.TestUtils.getMessage;
 import static org.briarproject.bramble.test.TestUtils.getRandomId;
-import static org.briarproject.bramble.versioning.ClientVersioningConstants.GROUP_KEY_CONTACT_ID;
 import static org.briarproject.bramble.versioning.ClientVersioningConstants.MSG_KEY_LOCAL;
 import static org.briarproject.bramble.versioning.ClientVersioningConstants.MSG_KEY_UPDATE_VERSION;
 import static org.junit.Assert.assertEquals;
@@ -60,8 +59,6 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 	private final ClientId clientId = getClientId();
 	private final long now = System.currentTimeMillis();
 	private final Transaction txn = new Transaction(null, false);
-	private final BdfDictionary groupMeta = BdfDictionary.of(
-			new BdfEntry(GROUP_KEY_CONTACT_ID, contact.getId().getInt()));
 
 	private ClientVersioningManagerImpl createInstance() {
 		context.checking(new Expectations() {{
@@ -123,8 +120,8 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 			oneOf(db).addGroup(txn, contactGroup);
 			oneOf(db).setGroupVisibility(txn, contact.getId(),
 					contactGroup.getId(), SHARED);
-			oneOf(clientHelper).mergeGroupMetadata(txn, contactGroup.getId(),
-					groupMeta);
+			oneOf(clientHelper).setContactId(txn, contactGroup.getId(),
+					contact.getId());
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(clientHelper).createMessage(contactGroup.getId(), now,
@@ -460,9 +457,8 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 			oneOf(db).deleteMessage(txn, oldRemoteUpdateId);
 			oneOf(db).deleteMessageMetadata(txn, oldRemoteUpdateId);
 			// Get contact ID
-			oneOf(clientHelper).getGroupMetadataAsDictionary(txn,
-					contactGroup.getId());
-			will(returnValue(groupMeta));
+			oneOf(clientHelper).getContactId(txn, contactGroup.getId());
+			will(returnValue(contact.getId()));
 			// No states or visibilities have changed
 		}});
 
@@ -492,10 +488,9 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 			// Load the latest local update
 			oneOf(clientHelper).getMessageAsList(txn, oldLocalUpdateId);
 			will(returnValue(oldLocalUpdateBody));
-			// Get client ID
-			oneOf(clientHelper).getGroupMetadataAsDictionary(txn,
-					contactGroup.getId());
-			will(returnValue(groupMeta));
+			// Get contact ID
+			oneOf(clientHelper).getContactId(txn, contactGroup.getId());
+			will(returnValue(contact.getId()));
 			// No states or visibilities have changed
 		}});
 
@@ -546,8 +541,6 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 		BdfDictionary newLocalUpdateMeta = BdfDictionary.of(
 				new BdfEntry(MSG_KEY_UPDATE_VERSION, 2L),
 				new BdfEntry(MSG_KEY_LOCAL, true));
-		BdfDictionary groupMeta = BdfDictionary.of(
-				new BdfEntry(GROUP_KEY_CONTACT_ID, contact.getId().getInt()));
 
 		context.checking(new Expectations() {{
 			oneOf(clientHelper).toList(newRemoteUpdate);
@@ -577,9 +570,8 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 			oneOf(clientHelper).addLocalMessage(txn, newLocalUpdate,
 					newLocalUpdateMeta, true, false);
 			// The client's visibility has changed
-			oneOf(clientHelper).getGroupMetadataAsDictionary(txn,
-					contactGroup.getId());
-			will(returnValue(groupMeta));
+			oneOf(clientHelper).getContactId(txn, contactGroup.getId());
+			will(returnValue(contact.getId()));
 			oneOf(db).getContact(txn, contact.getId());
 			will(returnValue(contact));
 			oneOf(hook).onClientVisibilityChanging(txn, contact, visibility);
@@ -619,8 +611,6 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 		BdfDictionary newLocalUpdateMeta = BdfDictionary.of(
 				new BdfEntry(MSG_KEY_UPDATE_VERSION, 2L),
 				new BdfEntry(MSG_KEY_LOCAL, true));
-		BdfDictionary groupMeta = BdfDictionary.of(
-				new BdfEntry(GROUP_KEY_CONTACT_ID, contact.getId().getInt()));
 
 		context.checking(new Expectations() {{
 			oneOf(clientHelper).toList(newRemoteUpdate);
@@ -650,9 +640,8 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 			oneOf(clientHelper).addLocalMessage(txn, newLocalUpdate,
 					newLocalUpdateMeta, true, false);
 			// The client's visibility has changed
-			oneOf(clientHelper).getGroupMetadataAsDictionary(txn,
-					contactGroup.getId());
-			will(returnValue(groupMeta));
+			oneOf(clientHelper).getContactId(txn, contactGroup.getId());
+			will(returnValue(contact.getId()));
 			oneOf(db).getContact(txn, contact.getId());
 			will(returnValue(contact));
 			oneOf(hook).onClientVisibilityChanging(txn, contact, INVISIBLE);

bramble-java/src/main/java/org/briarproject/bramble/BrambleJavaModule.java

@@ -8,9 +8,9 @@ import org.briarproject.bramble.system.JavaSystemModule;
 import dagger.Module;
 
 @Module(includes = {
+		CircumventionModule.class,
 		JavaNetworkModule.class,
 		JavaSystemModule.class,
-		CircumventionModule.class,
 		SocksModule.class
 })
 public class BrambleJavaModule {

briar-android/src/androidTestOfficial/java/org/briarproject/briar/android/BriarUiTestComponent.java

@@ -3,6 +3,7 @@ package org.briarproject.briar.android;
 import org.briarproject.bramble.BrambleAndroidModule;
 import org.briarproject.bramble.BrambleCoreModule;
 import org.briarproject.bramble.account.BriarAccountModule;
+import org.briarproject.bramble.system.ClockModule;
 import org.briarproject.briar.BriarCoreModule;
 import org.briarproject.briar.android.attachment.AttachmentModule;
 import org.briarproject.briar.android.attachment.media.MediaModule;
@@ -16,6 +17,7 @@ import dagger.Component;
 @Component(modules = {
 		AppModule.class,
 		AttachmentModule.class,
+		ClockModule.class,
 		MediaModule.class,
 		BriarCoreModule.class,
 		BrambleAndroidModule.class,

briar-android/src/androidTestScreenshot/java/org/briarproject/briar/android/BriarUiTestComponent.java

@@ -3,6 +3,7 @@ package org.briarproject.briar.android;
 import org.briarproject.bramble.BrambleAndroidModule;
 import org.briarproject.bramble.BrambleCoreModule;
 import org.briarproject.bramble.account.BriarAccountModule;
+import org.briarproject.bramble.system.ClockModule;
 import org.briarproject.briar.BriarCoreModule;
 import org.briarproject.briar.android.attachment.AttachmentModule;
 import org.briarproject.briar.android.attachment.media.MediaModule;
@@ -17,6 +18,7 @@ import dagger.Component;
 @Component(modules = {
 		AppModule.class,
 		AttachmentModule.class,
+		ClockModule.class,
 		MediaModule.class,
 		BriarCoreModule.class,
 		BrambleAndroidModule.class,

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

@@ -29,6 +29,7 @@ import org.briarproject.bramble.api.system.AndroidWakeLockManager;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
 import org.briarproject.bramble.plugin.tor.CircumventionProvider;
+import org.briarproject.bramble.system.ClockModule;
 import org.briarproject.briar.BriarCoreEagerSingletons;
 import org.briarproject.briar.BriarCoreModule;
 import org.briarproject.briar.android.attachment.AttachmentModule;
@@ -41,6 +42,7 @@ 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.attachment.AttachmentReader;
+import org.briarproject.briar.api.autodelete.AutoDeleteManager;
 import org.briarproject.briar.api.blog.BlogManager;
 import org.briarproject.briar.api.blog.BlogPostFactory;
 import org.briarproject.briar.api.blog.BlogSharingManager;
@@ -75,6 +77,7 @@ import dagger.Component;
 		BriarAccountModule.class,
 		AppModule.class,
 		AttachmentModule.class,
+		ClockModule.class,
 		MediaModule.class
 })
 public interface AndroidComponent
@@ -179,6 +182,8 @@ public interface AndroidComponent
 
 	AndroidWakeLockManager wakeLockManager();
 
+	AutoDeleteManager autoDeleteManager();
+
 	void inject(SignInReminderReceiver briarService);
 
 	void inject(BriarService briarService);

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

@@ -36,9 +36,9 @@ import org.briarproject.briar.android.keyagreement.ContactExchangeModule;
 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;
@@ -68,7 +68,6 @@ import static java.util.Collections.singletonList;
 import static java.util.Collections.singletonMap;
 import static org.briarproject.bramble.api.reporting.ReportingConstants.DEV_ONION_ADDRESS;
 import static org.briarproject.bramble.api.reporting.ReportingConstants.DEV_PUBLIC_KEY_HEX;
-import static org.briarproject.briar.android.TestingConstants.IS_DEBUG_BUILD;
 
 @Module(includes = {
 		SetupModule.class,
@@ -269,12 +268,12 @@ public class AppModule {
 
 			@Override
 			public boolean shouldEnableImageAttachments() {
-				return IS_DEBUG_BUILD;
+				return false;
 			}
 
 			@Override
 			public boolean shouldEnableProfilePictures() {
-				return IS_DEBUG_BUILD;
+				return false;
 			}
 		};
 	}

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

@@ -27,6 +27,7 @@ import org.briarproject.briar.android.contact.add.remote.NicknameFragment;
 import org.briarproject.briar.android.contact.add.remote.PendingContactListActivity;
 import org.briarproject.briar.android.conversation.AliasDialogFragment;
 import org.briarproject.briar.android.conversation.ConversationActivity;
+import org.briarproject.briar.android.conversation.ConversationSettingsDialog;
 import org.briarproject.briar.android.conversation.ImageActivity;
 import org.briarproject.briar.android.conversation.ImageFragment;
 import org.briarproject.briar.android.forum.CreateForumActivity;
@@ -238,4 +239,6 @@ public interface ActivityComponent {
 
 	void inject(ConfirmAvatarDialogFragment fragment);
 
+	void inject(ConversationSettingsDialog dialog);
+
 }

briar-android/src/main/java/org/briarproject/briar/android/blog/ReblogFragment.java

@@ -20,6 +20,7 @@ import org.briarproject.briar.android.fragment.BaseFragment;
 import org.briarproject.briar.android.view.TextInputView;
 import org.briarproject.briar.android.view.TextSendController;
 import org.briarproject.briar.android.view.TextSendController.SendListener;
+import org.briarproject.briar.android.view.TextSendController.SendState;
 import org.briarproject.briar.api.attachment.AttachmentHeader;
 
 import java.util.List;
@@ -27,6 +28,9 @@ import java.util.List;
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
 import static android.view.View.FOCUS_DOWN;
 import static android.view.View.GONE;
 import static android.view.View.INVISIBLE;
@@ -34,6 +38,7 @@ import static android.view.View.VISIBLE;
 import static java.util.Objects.requireNonNull;
 import static org.briarproject.briar.android.activity.BriarActivity.GROUP_ID;
 import static org.briarproject.briar.android.blog.BasePostFragment.POST_ID;
+import static org.briarproject.briar.android.view.TextSendController.SendState.SENT;
 import static org.briarproject.briar.api.blog.BlogConstants.MAX_BLOG_POST_TEXT_LENGTH;
 
 @MethodsNotNullByDefault
@@ -121,8 +126,8 @@ public class ReblogFragment extends BaseFragment implements SendListener {
 	}
 
 	@Override
-	public void onSendClick(@Nullable String text,
-			List<AttachmentHeader> headers) {
+	public LiveData<SendState> onSendClick(@Nullable String text,
+			List<AttachmentHeader> headers, long expectedAutoDeleteTimer) {
 		ui.input.hideSoftKeyboard();
 		feedController.repeatPost(item, text,
 				new UiExceptionHandler<DbException>(this) {
@@ -132,6 +137,7 @@ public class ReblogFragment extends BaseFragment implements SendListener {
 					}
 				});
 		finish();
+		return new MutableLiveData<>(SENT);
 	}
 
 	private void showProgressBar() {

briar-android/src/main/java/org/briarproject/briar/android/blog/WriteBlogPostActivity.java

@@ -31,12 +31,16 @@ import java.util.logging.Logger;
 import javax.inject.Inject;
 
 import androidx.annotation.Nullable;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
 
 import static android.view.View.GONE;
 import static android.view.View.VISIBLE;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
+import static org.briarproject.briar.android.view.TextSendController.SendState;
+import static org.briarproject.briar.android.view.TextSendController.SendState.SENT;
 import static org.briarproject.briar.api.blog.BlogConstants.MAX_BLOG_POST_TEXT_LENGTH;
 
 @MethodsNotNullByDefault
@@ -112,8 +116,8 @@ public class WriteBlogPostActivity extends BriarActivity
 	}
 
 	@Override
-	public void onSendClick(@Nullable String text,
-			List<AttachmentHeader> headers) {
+	public LiveData<SendState> onSendClick(@Nullable String text,
+			List<AttachmentHeader> headers, long expectedAutoDeleteTimer) {
 		if (isNullOrEmpty(text)) throw new AssertionError();
 
 		// hide publish button, show progress bar
@@ -122,6 +126,7 @@ public class WriteBlogPostActivity extends BriarActivity
 		progressBar.setVisibility(VISIBLE);
 
 		storePost(text);
+		return new MutableLiveData<>(SENT);
 	}
 
 	private void storePost(String text) {

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

@@ -31,6 +31,8 @@ import static org.briarproject.briar.android.util.UiUtils.showSoftKeyboard;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
+// TODO: we can probably switch to androidx DialogFragment here but need to
+//  test this properly
 public class AliasDialogFragment extends AppCompatDialogFragment {
 
 	final static String TAG = AliasDialogFragment.class.getName();

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

@@ -50,6 +50,7 @@ import org.briarproject.briar.android.blog.BlogActivity;
 import org.briarproject.briar.android.conversation.ConversationVisitor.AttachmentCache;
 import org.briarproject.briar.android.conversation.ConversationVisitor.TextCache;
 import org.briarproject.briar.android.forum.ForumActivity;
+import org.briarproject.briar.android.fragment.BaseFragment.BaseFragmentListener;
 import org.briarproject.briar.android.introduction.IntroductionActivity;
 import org.briarproject.briar.android.privategroup.conversation.GroupActivity;
 import org.briarproject.briar.android.util.BriarSnackbarBuilder;
@@ -59,6 +60,7 @@ import org.briarproject.briar.android.view.TextAttachmentController;
 import org.briarproject.briar.android.view.TextAttachmentController.AttachmentListener;
 import org.briarproject.briar.android.view.TextInputView;
 import org.briarproject.briar.android.view.TextSendController;
+import org.briarproject.briar.android.view.TextSendController.SendState;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
 import org.briarproject.briar.api.attachment.AttachmentHeader;
 import org.briarproject.briar.api.blog.BlogSharingManager;
@@ -138,12 +140,14 @@ import static org.briarproject.briar.android.util.UiUtils.observeOnce;
 import static org.briarproject.briar.android.view.AuthorView.setAvatar;
 import static org.briarproject.briar.api.messaging.MessagingConstants.MAX_ATTACHMENTS_PER_MESSAGE;
 import static org.briarproject.briar.api.messaging.MessagingConstants.MAX_PRIVATE_MESSAGE_TEXT_LENGTH;
+import static org.briarproject.briar.api.messaging.PrivateMessageFormat.TEXT_IMAGES_AUTO_DELETE;
+import static org.briarproject.briar.api.messaging.PrivateMessageFormat.TEXT_ONLY;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
 public class ConversationActivity extends BriarActivity
-		implements EventListener, ConversationListener, TextCache,
-		AttachmentCache, AttachmentListener, ActionMode.Callback {
+		implements BaseFragmentListener, EventListener, ConversationListener,
+		TextCache, AttachmentCache, AttachmentListener, ActionMode.Callback {
 
 	public static final String CONTACT_ID = "briar.CONTACT_ID";
 
@@ -268,15 +272,11 @@ public class ConversationActivity extends BriarActivity
 			ImagePreview imagePreview = findViewById(R.id.imagePreview);
 			sendController = new TextAttachmentController(textInputView,
 					imagePreview, this, viewModel);
-			viewModel.hasImageSupport().observe(this, new Observer<Boolean>() {
-				@Override
-				public void onChanged(@Nullable Boolean hasSupport) {
-					if (hasSupport != null && hasSupport) {
-						// TODO: remove cast when removing feature flag
-						((TextAttachmentController) sendController)
-								.setImagesSupported();
-						viewModel.hasImageSupport().removeObserver(this);
-					}
+			observeOnce(viewModel.getPrivateMessageFormat(), this, format -> {
+				if (format != TEXT_ONLY) {
+					// TODO: remove cast when removing feature flag
+					((TextAttachmentController) sendController)
+							.setImagesSupported();
 				}
 			});
 		} else {
@@ -286,6 +286,9 @@ public class ConversationActivity extends BriarActivity
 		textInputView.setMaxTextLength(MAX_PRIVATE_MESSAGE_TEXT_LENGTH);
 		textInputView.setReady(false);
 		textInputView.setOnKeyboardShownListener(this::scrollToBottom);
+
+		viewModel.getAutoDeleteTimer().observe(this, timer ->
+				sendController.setAutoDeleteTimer(timer));
 	}
 
 	private void scrollToBottom() {
@@ -369,6 +372,12 @@ public class ConversationActivity extends BriarActivity
 		// enable alias action if available
 		observeOnce(viewModel.getContactItem(), this, contact ->
 				menu.findItem(R.id.action_set_alias).setEnabled(true));
+		// show auto-delete timer setting only, if contacts supports it
+		observeOnce(viewModel.getPrivateMessageFormat(), this, format -> {
+			boolean visible = format == TEXT_IMAGES_AUTO_DELETE;
+			MenuItem item = menu.findItem(R.id.action_conversation_settings);
+			item.setVisible(visible);
+		});
 
 		return super.onCreateOptionsMenu(menu);
 	}
@@ -390,6 +399,10 @@ public class ConversationActivity extends BriarActivity
 				AliasDialogFragment.newInstance().show(
 						getSupportFragmentManager(), AliasDialogFragment.TAG);
 				return true;
+			case R.id.action_conversation_settings:
+				if (contactId == null) return false;
+				onAutoDeleteTimerNoticeClicked();
+				return true;
 			case R.id.action_delete_all_messages:
 				askToDeleteAllMessages();
 				return true;
@@ -640,8 +653,8 @@ public class ConversationActivity extends BriarActivity
 				supportFinishAfterTransition();
 			}
 		} else if (e instanceof ConversationMessageReceivedEvent) {
-			ConversationMessageReceivedEvent p =
-					(ConversationMessageReceivedEvent) e;
+			ConversationMessageReceivedEvent<?> p =
+					(ConversationMessageReceivedEvent<?>) e;
 			if (p.getContactId().equals(contactId)) {
 				LOG.info("Message received, adding");
 				onNewConversationMessage(p.getMessageHeader());
@@ -735,20 +748,13 @@ public class ConversationActivity extends BriarActivity
 	}
 
 	@Override
-	public void onSendClick(@Nullable String text,
-			List<AttachmentHeader> attachmentHeaders) {
+	public LiveData<SendState> onSendClick(@Nullable String text,
+			List<AttachmentHeader> attachmentHeaders,
+			long expectedAutoDeleteTimer) {
 		if (isNullOrEmpty(text) && attachmentHeaders.isEmpty())
 			throw new AssertionError();
-		long timestamp = System.currentTimeMillis();
-		timestamp = Math.max(timestamp, getMinTimestampForNewMessage());
-		viewModel.sendMessage(text, attachmentHeaders, timestamp);
-		textInputView.clearText();
-	}
-
-	private long getMinTimestampForNewMessage() {
-		// Don't use an earlier timestamp than the newest message
-		ConversationItem item = adapter.getLastItem();
-		return item == null ? 0 : item.getTime() + 1;
+		return viewModel
+				.sendMessage(text, attachmentHeaders, expectedAutoDeleteTimer);
 	}
 
 	private void onAddedPrivateMessage(@Nullable PrivateMessageHeader h) {
@@ -958,13 +964,11 @@ public class ConversationActivity extends BriarActivity
 			adapter.notifyItemChanged(position, item);
 		}
 		runOnDbThread(() -> {
-			long timestamp = System.currentTimeMillis();
-			timestamp = Math.max(timestamp, getMinTimestampForNewMessage());
 			try {
 				switch (item.getRequestType()) {
 					case INTRODUCTION:
 						respondToIntroductionRequest(item.getSessionId(),
-								accept, timestamp);
+								accept);
 						break;
 					case FORUM:
 						respondToForumRequest(item.getSessionId(), accept);
@@ -1038,11 +1042,18 @@ public class ConversationActivity extends BriarActivity
 		ActivityCompat.startActivity(this, i, options.toBundle());
 	}
 
+	@Override
+	public void onAutoDeleteTimerNoticeClicked() {
+		ConversationSettingsDialog dialog =
+				ConversationSettingsDialog.newInstance(contactId);
+		dialog.show(getSupportFragmentManager(),
+				ConversationSettingsDialog.TAG);
+	}
+
 	@DatabaseExecutor
 	private void respondToIntroductionRequest(SessionId sessionId,
-			boolean accept, long time) throws DbException {
-		introductionManager.respondToIntroduction(contactId, sessionId, time,
-				accept);
+			boolean accept) throws DbException {
+		introductionManager.respondToIntroduction(contactId, sessionId, accept);
 	}
 
 	@DatabaseExecutor

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

@@ -13,6 +13,8 @@ import org.briarproject.briar.R;
 import org.briarproject.briar.android.util.BriarAdapter;
 import org.briarproject.briar.android.util.ItemReturningAdapter;
 
+import java.util.Collection;
+
 import androidx.annotation.LayoutRes;
 import androidx.annotation.Nullable;
 import androidx.recyclerview.selection.SelectionTracker;
@@ -20,13 +22,14 @@ import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView.RecycledViewPool;
 
 import static androidx.recyclerview.widget.RecyclerView.NO_POSITION;
+import static org.briarproject.briar.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
 
 @NotNullByDefault
 class ConversationAdapter
 		extends BriarAdapter<ConversationItem, ConversationItemViewHolder>
 		implements ItemReturningAdapter<ConversationItem> {
 
-	private ConversationListener listener;
+	private final ConversationListener listener;
 	private final RecycledViewPool imageViewPool;
 	private final ImageItemDecoration imageItemDecoration;
 	@Nullable
@@ -65,22 +68,20 @@ class ConversationAdapter
 			@LayoutRes int type) {
 		View v = LayoutInflater.from(viewGroup.getContext()).inflate(
 				type, viewGroup, false);
-		switch (type) {
-			case R.layout.list_item_conversation_msg_in:
-				return new ConversationMessageViewHolder(v, listener, true,
-						imageViewPool, imageItemDecoration);
-			case R.layout.list_item_conversation_msg_out:
-				return new ConversationMessageViewHolder(v, listener, false,
-						imageViewPool, imageItemDecoration);
-			case R.layout.list_item_conversation_notice_in:
-				return new ConversationNoticeViewHolder(v, listener, true);
-			case R.layout.list_item_conversation_notice_out:
-				return new ConversationNoticeViewHolder(v, listener, false);
-			case R.layout.list_item_conversation_request:
-				return new ConversationRequestViewHolder(v, listener, true);
-			default:
-				throw new IllegalArgumentException("Unknown ConversationItem");
+		if (type == R.layout.list_item_conversation_msg_in) {
+			return new ConversationMessageViewHolder(v, listener, true,
+					imageViewPool, imageItemDecoration);
+		} else if (type == R.layout.list_item_conversation_msg_out) {
+			return new ConversationMessageViewHolder(v, listener, false,
+					imageViewPool, imageItemDecoration);
+		} else if (type == R.layout.list_item_conversation_notice_in) {
+			return new ConversationNoticeViewHolder(v, listener, true);
+		} else if (type == R.layout.list_item_conversation_notice_out) {
+			return new ConversationNoticeViewHolder(v, listener, false);
+		} else if (type == R.layout.list_item_conversation_request) {
+			return new ConversationRequestViewHolder(v, listener, true);
 		}
+		throw new IllegalArgumentException("Unknown ConversationItem");
 	}
 
 	@Override
@@ -107,22 +108,49 @@ class ConversationAdapter
 		return c1.equals(c2);
 	}
 
+	@Override
+	public void add(ConversationItem item) {
+		items.beginBatchedUpdates();
+		items.add(item);
+		updateTimersInBatch();
+		items.endBatchedUpdates();
+	}
+
+	@Override
+	public void addAll(Collection<ConversationItem> itemsToAdd) {
+		items.beginBatchedUpdates();
+		// there can be items already in the adapter
+		// SortedList takes care of duplicates and detecting changed items
+		items.addAll(itemsToAdd);
+		updateTimersInBatch();
+		items.endBatchedUpdates();
+	}
+
+	private void updateTimersInBatch() {
+		long lastTimerIncoming = NO_AUTO_DELETE_TIMER;
+		long lastTimerOutgoing = NO_AUTO_DELETE_TIMER;
+		for (int i = 0; i < items.size(); i++) {
+			ConversationItem c = items.get(i);
+			boolean itemChanged;
+			boolean timerChanged;
+			if (c.isIncoming()) {
+				timerChanged = lastTimerIncoming != c.getAutoDeleteTimer();
+				lastTimerIncoming = c.getAutoDeleteTimer();
+			} else {
+				timerChanged = lastTimerOutgoing != c.getAutoDeleteTimer();
+				lastTimerOutgoing = c.getAutoDeleteTimer();
+			}
+			itemChanged = c.setTimerNoticeVisible(timerChanged);
+			if (itemChanged) items.updateItemAt(i, c);
+		}
+	}
+
 	void setSelectionTracker(SelectionTracker<String> tracker) {
 		this.tracker = tracker;
 	}
 
-	@Nullable
-	ConversationItem getLastItem() {
-		if (items.size() > 0) {
-			return items.get(items.size() - 1);
-		} else {
-			return null;
-		}
-	}
-
 	SparseArray<ConversationItem> getOutgoingMessages() {
 		SparseArray<ConversationItem> messages = new SparseArray<>();
-
 		for (int i = 0; i < items.size(); i++) {
 			ConversationItem item = items.get(i);
 			if (!item.isIncoming()) {

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

@@ -9,6 +9,7 @@ import javax.annotation.Nullable;
 import javax.annotation.concurrent.NotThreadSafe;
 
 import androidx.annotation.LayoutRes;
+import androidx.lifecycle.LiveData;
 
 import static org.briarproject.bramble.util.StringUtils.toHexString;
 
@@ -22,20 +23,25 @@ abstract class ConversationItem {
 	protected String text;
 	private final MessageId id;
 	private final GroupId groupId;
-	private final long time;
+	private final long time, autoDeleteTimer;
 	private final boolean isIncoming;
-	private boolean read, sent, seen;
+	private final LiveData<String> contactName;
+	private boolean read, sent, seen, showTimerNotice;
 
-	ConversationItem(@LayoutRes int layoutRes, ConversationMessageHeader h) {
+	ConversationItem(@LayoutRes int layoutRes, ConversationMessageHeader h,
+			LiveData<String> contactName) {
 		this.layoutRes = layoutRes;
 		this.text = null;
 		this.id = h.getId();
 		this.groupId = h.getGroupId();
 		this.time = h.getTimestamp();
+		this.autoDeleteTimer = h.getAutoDeleteTimer();
 		this.read = h.isRead();
 		this.sent = h.isSent();
 		this.seen = h.isSeen();
 		this.isIncoming = !h.isLocal();
+		this.contactName = contactName;
+		this.showTimerNotice = false;
 	}
 
 	@LayoutRes
@@ -68,6 +74,10 @@ abstract class ConversationItem {
 		return time;
 	}
 
+	public long getAutoDeleteTimer() {
+		return autoDeleteTimer;
+	}
+
 	/**
 	 * Only useful for incoming messages.
 	 */
@@ -111,4 +121,25 @@ abstract class ConversationItem {
 		return isIncoming;
 	}
 
+	public LiveData<String> getContactName() {
+		return contactName;
+	}
+
+	/**
+	 * Set this to true when {@link #getAutoDeleteTimer()} has changed
+	 * since the last message from the same peer.
+	 *
+	 * @return true if the value was set, false if it was already set.
+	 */
+	boolean setTimerNoticeVisible(boolean visible) {
+		if (this.showTimerNotice != visible) {
+			this.showTimerNotice = visible;
+			return true;
+		}
+		return false;
+	}
+
+	boolean isTimerNoticeVisible() {
+		return showTimerNotice;
+	}
 }

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

@@ -1,6 +1,8 @@
 package org.briarproject.briar.android.conversation;
 
+import android.content.Context;
 import android.view.View;
+import android.widget.ImageView;
 import android.widget.TextView;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
@@ -12,8 +14,11 @@ import androidx.annotation.UiThread;
 import androidx.constraintlayout.widget.ConstraintLayout;
 import androidx.recyclerview.widget.RecyclerView.ViewHolder;
 
+import static android.view.View.GONE;
+import static android.view.View.VISIBLE;
 import static org.briarproject.bramble.util.StringUtils.trim;
 import static org.briarproject.briar.android.util.UiUtils.formatDate;
+import static org.briarproject.briar.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
 
 @UiThread
 @NotNullByDefault
@@ -24,8 +29,9 @@ abstract class ConversationItemViewHolder extends ViewHolder {
 	protected final ConstraintLayout layout;
 	@Nullable
 	private final OutItemViewHolder outViewHolder;
-	private final TextView text;
+	private final TextView topNotice, text;
 	protected final TextView time;
+	protected final ImageView bomb;
 	@Nullable
 	private String itemKey = null;
 
@@ -33,11 +39,13 @@ abstract class ConversationItemViewHolder extends ViewHolder {
 			boolean isIncoming) {
 		super(v);
 		this.listener = listener;
-		this.outViewHolder = isIncoming ? null : new OutItemViewHolder(v);
+		outViewHolder = isIncoming ? null : new OutItemViewHolder(v);
 		root = v;
+		topNotice = v.findViewById(R.id.topNotice);
 		layout = v.findViewById(R.id.layout);
 		text = v.findViewById(R.id.text);
 		time = v.findViewById(R.id.time);
+		bomb = v.findViewById(R.id.bomb);
 	}
 
 	@CallSuper
@@ -45,6 +53,8 @@ abstract class ConversationItemViewHolder extends ViewHolder {
 		itemKey = item.getKey();
 		root.setActivated(selected);
 
+		setTopNotice(item);
+
 		if (item.getText() != null) {
 			text.setText(trim(item.getText()));
 		}
@@ -52,6 +62,9 @@ abstract class ConversationItemViewHolder extends ViewHolder {
 		long timestamp = item.getTime();
 		time.setText(formatDate(time.getContext(), timestamp));
 
+		boolean showBomb = item.getAutoDeleteTimer() != NO_AUTO_DELETE_TIMER;
+		bomb.setVisibility(showBomb ? VISIBLE : GONE);
+
 		if (outViewHolder != null) outViewHolder.bind(item);
 	}
 
@@ -64,4 +77,31 @@ abstract class ConversationItemViewHolder extends ViewHolder {
 		return itemKey;
 	}
 
+	private void setTopNotice(ConversationItem item) {
+		if (item.isTimerNoticeVisible()) {
+			Context ctx = itemView.getContext();
+			topNotice.setVisibility(VISIBLE);
+			boolean enabled = item.getAutoDeleteTimer() != NO_AUTO_DELETE_TIMER;
+			String tapToLearnMore = ctx.getString(R.string.tap_to_learn_more);
+			String text;
+			if (item.isIncoming()) {
+				String name = item.getContactName().getValue();
+				int strRes = enabled ?
+						R.string.auto_delete_msg_contact_enabled :
+						R.string.auto_delete_msg_contact_disabled;
+				text = ctx.getString(strRes, name, tapToLearnMore);
+			} else {
+				int strRes = enabled ?
+						R.string.auto_delete_msg_you_enabled :
+						R.string.auto_delete_msg_you_disabled;
+				text = ctx.getString(strRes, tapToLearnMore);
+			}
+			topNotice.setText(text);
+			topNotice.setOnClickListener(
+					v -> listener.onAutoDeleteTimerNoticeClicked());
+		} else {
+			topNotice.setVisibility(GONE);
+		}
+	}
+
 }

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

@@ -18,4 +18,6 @@ interface ConversationListener {
 	void onAttachmentClicked(View view, ConversationMessageItem messageItem,
 			AttachmentItem attachmentItem);
 
+	void onAutoDeleteTimerNoticeClicked();
+
 }

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

@@ -10,6 +10,7 @@ import javax.annotation.concurrent.NotThreadSafe;
 
 import androidx.annotation.LayoutRes;
 import androidx.annotation.UiThread;
+import androidx.lifecycle.LiveData;
 
 @NotThreadSafe
 @NotNullByDefault
@@ -18,8 +19,8 @@ class ConversationMessageItem extends ConversationItem {
 	private final List<AttachmentItem> attachments;
 
 	ConversationMessageItem(@LayoutRes int layoutRes, PrivateMessageHeader h,
-			List<AttachmentItem> attachments) {
-		super(layoutRes, h);
+			LiveData<String> contactName, List<AttachmentItem> attachments) {
+		super(layoutRes, h, contactName);
 		this.attachments = attachments;
 	}
 

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

@@ -1,5 +1,6 @@
 package org.briarproject.briar.android.conversation;
 
+import android.content.res.ColorStateList;
 import android.view.View;
 import android.view.ViewGroup;
 
@@ -14,6 +15,7 @@ import androidx.recyclerview.widget.RecyclerView.RecycledViewPool;
 
 import static androidx.constraintlayout.widget.ConstraintSet.WRAP_CONTENT;
 import static androidx.core.content.ContextCompat.getColor;
+import static androidx.core.widget.ImageViewCompat.setImageTintList;
 
 @UiThread
 @NotNullByDefault
@@ -84,6 +86,7 @@ class ConversationMessageViewHolder extends ConversationItemViewHolder {
 		if (item.getText() == null) {
 			statusLayout.setBackgroundResource(R.drawable.msg_status_bubble);
 			time.setTextColor(timeColorBubble);
+			setImageTintList(bomb, ColorStateList.valueOf(timeColorBubble));
 			constraintSet = imageConstraints;
 		} else {
 			resetStatusLayoutForText();
@@ -111,6 +114,7 @@ class ConversationMessageViewHolder extends ConversationItemViewHolder {
 		// also reset padding (the background drawable defines some)
 		statusLayout.setPadding(0, 0, 0, 0);
 		time.setTextColor(timeColor);
+		setImageTintList(bomb, ColorStateList.valueOf(timeColor));
 	}
 
 }

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

@@ -8,6 +8,7 @@ import javax.annotation.Nullable;
 import javax.annotation.concurrent.NotThreadSafe;
 
 import androidx.annotation.LayoutRes;
+import androidx.lifecycle.LiveData;
 
 @NotThreadSafe
 @NotNullByDefault
@@ -17,15 +18,15 @@ class ConversationNoticeItem extends ConversationItem {
 	private final String msgText;
 
 	ConversationNoticeItem(@LayoutRes int layoutRes, String text,
-			ConversationRequest r) {
-		super(layoutRes, r);
+			LiveData<String> contactName, ConversationRequest<?> r) {
+		super(layoutRes, r, contactName);
 		this.text = text;
 		this.msgText = r.getText();
 	}
 
 	ConversationNoticeItem(@LayoutRes int layoutRes, String text,
-			ConversationResponse r) {
-		super(layoutRes, r);
+			LiveData<String> contactName, ConversationResponse r) {
+		super(layoutRes, r, contactName);
 		this.text = text;
 		this.msgText = null;
 	}

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

@@ -11,6 +11,7 @@ import javax.annotation.Nullable;
 import javax.annotation.concurrent.NotThreadSafe;
 
 import androidx.annotation.LayoutRes;
+import androidx.lifecycle.LiveData;
 
 @NotThreadSafe
 @NotNullByDefault
@@ -26,14 +27,15 @@ class ConversationRequestItem extends ConversationNoticeItem {
 	private boolean answered;
 
 	ConversationRequestItem(@LayoutRes int layoutRes, String text,
-			RequestType type, ConversationRequest r) {
-		super(layoutRes, text, r);
+			LiveData<String> contactName, RequestType type,
+			ConversationRequest<?> r) {
+		super(layoutRes, text, contactName, r);
 		this.requestType = type;
 		this.sessionId = r.getSessionId();
 		this.answered = r.wasAnswered();
 		if (r instanceof InvitationRequest) {
 			this.requestedGroupId = ((Shareable) r.getNameable()).getId();
-			this.canBeOpened = ((InvitationRequest) r).canBeOpened();
+			this.canBeOpened = ((InvitationRequest<?>) r).canBeOpened();
 		} else {
 			this.requestedGroupId = null;
 			this.canBeOpened = false;

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

@@ -0,0 +1,122 @@
+package org.briarproject.briar.android.conversation;
+
+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.contact.ContactId;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+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.BaseFragment;
+
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import androidx.annotation.Nullable;
+import androidx.appcompat.widget.SwitchCompat;
+import androidx.appcompat.widget.Toolbar;
+import androidx.fragment.app.DialogFragment;
+import androidx.fragment.app.FragmentActivity;
+import androidx.lifecycle.ViewModelProvider;
+
+import static org.briarproject.briar.android.conversation.ConversationActivity.CONTACT_ID;
+import static org.briarproject.briar.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public class ConversationSettingsDialog extends DialogFragment {
+
+	final static String TAG = ConversationSettingsDialog.class.getName();
+
+	private static final Logger LOG = Logger.getLogger(TAG);
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private ConversationViewModel viewModel;
+
+	static ConversationSettingsDialog newInstance(ContactId contactId) {
+		Bundle args = new Bundle();
+		args.putInt(CONTACT_ID, contactId.getInt());
+		ConversationSettingsDialog dialog = new ConversationSettingsDialog();
+		dialog.setArguments(args);
+		return dialog;
+	}
+
+	@Override
+	public void onAttach(Context context) {
+		super.onAttach(context);
+		injectFragment(((BaseFragment.BaseFragmentListener) context)
+				.getActivityComponent());
+	}
+
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+		viewModel = new ViewModelProvider(requireActivity(), viewModelFactory)
+				.get(ConversationViewModel.class);
+	}
+
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		setStyle(DialogFragment.STYLE_NO_FRAME,
+				R.style.BriarFullScreenDialogTheme);
+	}
+
+	@Nullable
+	@Override
+	public View onCreateView(LayoutInflater inflater,
+			@Nullable ViewGroup container,
+			@Nullable Bundle savedInstanceState) {
+		View view = inflater.inflate(R.layout.fragment_conversation_settings,
+				container, false);
+
+		Bundle args = requireArguments();
+		int id = args.getInt(CONTACT_ID, -1);
+		if (id == -1) throw new IllegalStateException();
+		ContactId contactId = new ContactId(id);
+
+		FragmentActivity activity = requireActivity();
+		viewModel = new ViewModelProvider(activity, viewModelFactory)
+				.get(ConversationViewModel.class);
+		viewModel.setContactId(contactId);
+
+		Toolbar toolbar = view.findViewById(R.id.toolbar);
+		toolbar.setNavigationOnClickListener(v -> dismiss());
+
+		SwitchCompat switchDisappearingMessages = view.findViewById(
+				R.id.switchDisappearingMessages);
+		switchDisappearingMessages.setOnCheckedChangeListener(
+				(button, value) -> viewModel.setAutoDeleteTimerEnabled(value));
+
+		TextView buttonLearnMore =
+				view.findViewById(R.id.buttonLearnMore);
+		buttonLearnMore.setOnClickListener(e -> showLearnMoreDialog());
+
+		viewModel.getAutoDeleteTimer()
+				.observe(getViewLifecycleOwner(), timer -> {
+					LOG.info("Received auto delete timer: " + timer);
+					boolean disappearingMessages =
+							timer != NO_AUTO_DELETE_TIMER;
+					switchDisappearingMessages
+							.setChecked(disappearingMessages);
+					switchDisappearingMessages.setEnabled(true);
+				});
+
+		return view;
+	}
+
+	private void showLearnMoreDialog() {
+		ConversationSettingsLearnMoreDialog
+				dialog = new ConversationSettingsLearnMoreDialog();
+		dialog.show(getChildFragmentManager(),
+				ConversationSettingsLearnMoreDialog.TAG);
+	}
+
+}

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

@@ -0,0 +1,43 @@
+package org.briarproject.briar.android.conversation;
+
+import android.app.Dialog;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.briar.R;
+
+import androidx.annotation.Nullable;
+import androidx.appcompat.app.AlertDialog;
+import androidx.fragment.app.DialogFragment;
+import androidx.fragment.app.FragmentActivity;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public class ConversationSettingsLearnMoreDialog extends DialogFragment {
+
+	final static String TAG =
+			ConversationSettingsLearnMoreDialog.class.getName();
+
+	@Override
+	public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
+		FragmentActivity activity = requireActivity();
+
+		AlertDialog.Builder builder = new AlertDialog.Builder(activity,
+				R.style.OnboardingDialogTheme);
+
+		LayoutInflater inflater = LayoutInflater.from(builder.getContext());
+		View view = inflater.inflate(
+				R.layout.fragment_conversation_settings_learn_more, null);
+		builder.setView(view);
+
+		builder.setTitle(R.string.disappearing_messages_title);
+		builder.setPositiveButton(R.string.ok, null);
+
+		return builder.create();
+	}
+
+
+}

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

@@ -10,6 +10,7 @@ import org.briarproject.bramble.api.contact.ContactManager;
 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.db.Transaction;
 import org.briarproject.bramble.api.db.TransactionManager;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
@@ -28,16 +29,22 @@ import org.briarproject.briar.android.attachment.AttachmentResult;
 import org.briarproject.briar.android.attachment.AttachmentRetriever;
 import org.briarproject.briar.android.contact.ContactItem;
 import org.briarproject.briar.android.util.UiUtils;
+import org.briarproject.briar.android.view.TextSendController.SendState;
 import org.briarproject.briar.android.viewmodel.DbViewModel;
 import org.briarproject.briar.android.viewmodel.LiveEvent;
 import org.briarproject.briar.android.viewmodel.MutableLiveEvent;
 import org.briarproject.briar.api.attachment.AttachmentHeader;
+import org.briarproject.briar.api.autodelete.AutoDeleteManager;
+import org.briarproject.briar.api.autodelete.UnexpectedTimerException;
+import org.briarproject.briar.api.autodelete.event.AutoDeleteTimerMirroredEvent;
 import org.briarproject.briar.api.avatar.event.AvatarUpdatedEvent;
+import org.briarproject.briar.api.conversation.ConversationManager;
 import org.briarproject.briar.api.identity.AuthorInfo;
 import org.briarproject.briar.api.identity.AuthorManager;
 import org.briarproject.briar.api.messaging.MessagingManager;
 import org.briarproject.briar.api.messaging.PrivateMessage;
 import org.briarproject.briar.api.messaging.PrivateMessageFactory;
+import org.briarproject.briar.api.messaging.PrivateMessageFormat;
 import org.briarproject.briar.api.messaging.PrivateMessageHeader;
 import org.briarproject.briar.api.messaging.event.AttachmentReceivedEvent;
 
@@ -55,6 +62,8 @@ import androidx.lifecycle.MutableLiveData;
 
 import static androidx.lifecycle.Transformations.map;
 import static java.util.Objects.requireNonNull;
+import static java.util.concurrent.TimeUnit.DAYS;
+import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
@@ -62,6 +71,12 @@ import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.LogUtils.now;
 import static org.briarproject.briar.android.settings.SettingsFragment.SETTINGS_NAMESPACE;
 import static org.briarproject.briar.android.util.UiUtils.observeForeverOnce;
+import static org.briarproject.briar.android.view.TextSendController.SendState.ERROR;
+import static org.briarproject.briar.android.view.TextSendController.SendState.SENT;
+import static org.briarproject.briar.android.view.TextSendController.SendState.UNEXPECTED_TIMER;
+import static org.briarproject.briar.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
+import static org.briarproject.briar.api.messaging.PrivateMessageFormat.TEXT_IMAGES;
+import static org.briarproject.briar.api.messaging.PrivateMessageFormat.TEXT_ONLY;
 
 @NotNullByDefault
 public class ConversationViewModel extends DbViewModel
@@ -84,6 +99,8 @@ public class ConversationViewModel extends DbViewModel
 	private final PrivateMessageFactory privateMessageFactory;
 	private final AttachmentRetriever attachmentRetriever;
 	private final AttachmentCreator attachmentCreator;
+	private final AutoDeleteManager autoDeleteManager;
+	private final ConversationManager conversationManager;
 
 	@Nullable
 	private ContactId contactId = null;
@@ -92,7 +109,7 @@ public class ConversationViewModel extends DbViewModel
 	private final LiveData<String> contactName = map(contactItem, c ->
 			UiUtils.getContactDisplayName(c.getContact()));
 	private final LiveData<GroupId> messagingGroupId;
-	private final MutableLiveData<Boolean> imageSupport =
+	private final MutableLiveData<PrivateMessageFormat> privateMessageFormat =
 			new MutableLiveData<>();
 	private final MutableLiveEvent<Boolean> showImageOnboarding =
 			new MutableLiveEvent<>();
@@ -100,8 +117,10 @@ public class ConversationViewModel extends DbViewModel
 			new MutableLiveEvent<>();
 	private final MutableLiveData<Boolean> showIntroductionAction =
 			new MutableLiveData<>();
-	private final MutableLiveData<Boolean> contactDeleted =
+	private final MutableLiveData<Long> autoDeleteTimer =
 			new MutableLiveData<>();
+	private final MutableLiveData<Boolean> contactDeleted =
+			new MutableLiveData<>(false);
 	private final MutableLiveEvent<PrivateMessageHeader> addedHeader =
 			new MutableLiveEvent<>();
 
@@ -118,7 +137,9 @@ public class ConversationViewModel extends DbViewModel
 			SettingsManager settingsManager,
 			PrivateMessageFactory privateMessageFactory,
 			AttachmentRetriever attachmentRetriever,
-			AttachmentCreator attachmentCreator) {
+			AttachmentCreator attachmentCreator,
+			AutoDeleteManager autoDeleteManager,
+			ConversationManager conversationManager) {
 		super(application, dbExecutor, lifecycleManager, db, androidExecutor);
 		this.db = db;
 		this.eventBus = eventBus;
@@ -129,10 +150,10 @@ public class ConversationViewModel extends DbViewModel
 		this.privateMessageFactory = privateMessageFactory;
 		this.attachmentRetriever = attachmentRetriever;
 		this.attachmentCreator = attachmentCreator;
+		this.autoDeleteManager = autoDeleteManager;
+		this.conversationManager = conversationManager;
 		messagingGroupId = map(contactItem, c ->
 				messagingManager.getContactGroup(c.getContact()).getId());
-		contactDeleted.setValue(false);
-
 		eventBus.addListener(this);
 	}
 
@@ -152,6 +173,11 @@ public class ConversationViewModel extends DbViewModel
 				runOnDbThread(() -> attachmentRetriever
 						.loadAttachmentItem(a.getMessageId()));
 			}
+		} else if (e instanceof AutoDeleteTimerMirroredEvent) {
+			AutoDeleteTimerMirroredEvent a = (AutoDeleteTimerMirroredEvent) e;
+			if (a.getContactId().equals(contactId)) {
+				autoDeleteTimer.postValue(a.getNewTimer());
+			}
 		} else if (e instanceof AvatarUpdatedEvent) {
 			AvatarUpdatedEvent a = (AvatarUpdatedEvent) e;
 			if (a.getContactId().equals(contactId)) {
@@ -201,6 +227,11 @@ public class ConversationViewModel extends DbViewModel
 				contactItem.postValue(new ContactItem(c, authorInfo));
 				logDuration(LOG, "Loading contact", start);
 				start = now();
+				long timer = db.transactionWithResult(true, txn ->
+						autoDeleteManager.getAutoDeleteTimer(txn, contactId));
+				autoDeleteTimer.postValue(timer);
+				logDuration(LOG, "Getting auto-delete timer", start);
+				start = now();
 				checkFeaturesAndOnboarding(contactId);
 				logDuration(LOG, "Checking for image support", start);
 			} catch (NoSuchContactException e) {
@@ -235,20 +266,6 @@ public class ConversationViewModel extends DbViewModel
 		});
 	}
 
-	@UiThread
-	void sendMessage(@Nullable String text,
-			List<AttachmentHeader> headers, long timestamp) {
-		// messagingGroupId is loaded with the contact
-		observeForeverOnce(messagingGroupId, groupId -> {
-			requireNonNull(groupId);
-			observeForeverOnce(imageSupport, hasImageSupport -> {
-				requireNonNull(hasImageSupport);
-				createMessage(groupId, text, headers, timestamp,
-						hasImageSupport);
-			});
-		});
-	}
-
 	@Override
 	@UiThread
 	public LiveData<AttachmentResult> storeAttachments(Collection<Uri> uris,
@@ -275,10 +292,12 @@ public class ConversationViewModel extends DbViewModel
 
 	@DatabaseExecutor
 	private void checkFeaturesAndOnboarding(ContactId c) throws DbException {
-		// check if images are supported
-		boolean imagesSupported = db.transactionWithResult(true, txn ->
-				messagingManager.contactSupportsImages(txn, c));
-		imageSupport.postValue(imagesSupported);
+		// check if images and auto-deletion are supported
+		PrivateMessageFormat format = db.transactionWithResult(true, txn ->
+				messagingManager.getContactMessageFormat(txn, c));
+		if (LOG.isLoggable(INFO))
+			LOG.info("PrivateMessageFormat loaded: " + format.name());
+		privateMessageFormat.postValue(format);
 
 		// check if introductions are supported
 		Collection<Contact> contacts = contactManager.getContacts();
@@ -287,7 +306,7 @@ public class ConversationViewModel extends DbViewModel
 
 		// we only show one onboarding dialog at a time
 		Settings settings = settingsManager.getSettings(SETTINGS_NAMESPACE);
-		if (imagesSupported &&
+		if (format != TEXT_ONLY &&
 				settings.getBoolean(SHOW_ONBOARDING_IMAGE, true)) {
 			onOnboardingShown(SHOW_ONBOARDING_IMAGE);
 			showImageOnboarding.postEvent(true);
@@ -306,39 +325,82 @@ public class ConversationViewModel extends DbViewModel
 	}
 
 	@UiThread
-	private void createMessage(GroupId groupId, @Nullable String text,
-			List<AttachmentHeader> headers, long timestamp,
-			boolean hasImageSupport) {
+	LiveData<SendState> sendMessage(@Nullable String text,
+			List<AttachmentHeader> headers, long expectedTimer) {
+		MutableLiveData<SendState> liveData = new MutableLiveData<>();
+		runOnDbThread(() -> {
+			try {
+				db.transaction(false, txn -> {
+					long start = now();
+					PrivateMessage m = createMessage(txn, text, headers,
+							expectedTimer);
+					messagingManager.addLocalMessage(txn, m);
+					logDuration(LOG, "Storing message", start);
+					Message message = m.getMessage();
+					PrivateMessageHeader h = new PrivateMessageHeader(
+							message.getId(), message.getGroupId(),
+							message.getTimestamp(), true, true, false, false,
+							m.hasText(), m.getAttachmentHeaders(),
+							m.getAutoDeleteTimer());
+					// TODO add text to cache when available here
+					MessageId id = message.getId();
+					txn.attach(() -> {
+						attachmentCreator.onAttachmentsSent(id);
+						liveData.setValue(SENT);
+						addedHeader.setEvent(h);
+					});
+				});
+			} catch (UnexpectedTimerException e) {
+				liveData.postValue(UNEXPECTED_TIMER);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+				liveData.postValue(ERROR);
+			}
+		});
+		return liveData;
+	}
+
+	private PrivateMessage createMessage(Transaction txn, @Nullable String text,
+			List<AttachmentHeader> headers, long expectedTimer)
+			throws DbException {
+		// Sending is only possible (setReady(true)) after loading all messages
+		// which happens after the contact has been loaded.
+		// privateMessageFormat is loaded together with contact
+		Contact contact = requireNonNull(contactItem.getValue()).getContact();
+		GroupId groupId = messagingManager.getContactGroup(contact).getId();
+		PrivateMessageFormat format =
+				requireNonNull(privateMessageFormat.getValue());
+		long timestamp = conversationManager
+				.getTimestampForOutgoingMessage(txn, requireNonNull(contactId));
 		try {
-			PrivateMessage pm;
-			if (hasImageSupport) {
-				pm = privateMessageFactory.createPrivateMessage(groupId,
+			if (format == TEXT_ONLY) {
+				return privateMessageFactory.createLegacyPrivateMessage(
+						groupId, timestamp, requireNonNull(text));
+			} else if (format == TEXT_IMAGES) {
+				return privateMessageFactory.createPrivateMessage(groupId,
 						timestamp, text, headers);
 			} else {
-				pm = privateMessageFactory.createLegacyPrivateMessage(
-						groupId, timestamp, requireNonNull(text));
+				long timer = autoDeleteManager
+						.getAutoDeleteTimer(txn, contactId, timestamp);
+				if (timer != expectedTimer)
+					throw new UnexpectedTimerException();
+				return privateMessageFactory.createPrivateMessage(groupId,
+						timestamp, text, headers, timer);
 			}
-			storeMessage(pm);
 		} catch (FormatException e) {
 			throw new AssertionError(e);
 		}
 	}
 
-	@UiThread
-	private void storeMessage(PrivateMessage m) {
-		attachmentCreator.onAttachmentsSent(m.getMessage().getId());
+	void setAutoDeleteTimerEnabled(boolean enabled) {
+		final long timer = enabled ? DAYS.toMillis(7) : NO_AUTO_DELETE_TIMER;
+		// ContactId is set before menu gets inflated and UI interaction
+		final ContactId c = requireNonNull(contactId);
 		runOnDbThread(() -> {
 			try {
-				long start = now();
-				messagingManager.addLocalMessage(m);
-				logDuration(LOG, "Storing message", start);
-				Message message = m.getMessage();
-				PrivateMessageHeader h = new PrivateMessageHeader(
-						message.getId(), message.getGroupId(),
-						message.getTimestamp(), true, true, false, false,
-						m.hasText(), m.getAttachmentHeaders());
-				// TODO add text to cache when available here
-				addedHeader.postEvent(h);
+				db.transaction(false, txn ->
+						autoDeleteManager.setAutoDeleteTimer(txn, c, timer));
+				autoDeleteTimer.postValue(timer);
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 			}
@@ -357,8 +419,8 @@ public class ConversationViewModel extends DbViewModel
 		return contactName;
 	}
 
-	LiveData<Boolean> hasImageSupport() {
-		return imageSupport;
+	LiveData<PrivateMessageFormat> getPrivateMessageFormat() {
+		return privateMessageFormat;
 	}
 
 	LiveEvent<Boolean> showImageOnboarding() {
@@ -373,6 +435,10 @@ public class ConversationViewModel extends DbViewModel
 		return showIntroductionAction;
 	}
 
+	LiveData<Long> getAutoDeleteTimer() {
+		return autoDeleteTimer;
+	}
+
 	LiveData<Boolean> isContactDeleted() {
 		return contactDeleted;
 	}

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

@@ -60,10 +60,12 @@ class ConversationVisitor implements
 		}
 		if (h.isLocal()) {
 			item = new ConversationMessageItem(
-					R.layout.list_item_conversation_msg_out, h, attachments);
+					R.layout.list_item_conversation_msg_out, h, contactName,
+					attachments);
 		} else {
 			item = new ConversationMessageItem(
-					R.layout.list_item_conversation_msg_in, h, attachments);
+					R.layout.list_item_conversation_msg_in, h, contactName,
+					attachments);
 		}
 		if (h.hasText()) {
 			String text = textCache.getText(h.getId());
@@ -79,13 +81,15 @@ class ConversationVisitor implements
 			String text = ctx.getString(R.string.blogs_sharing_invitation_sent,
 					r.getName(), contactName.getValue());
 			return new ConversationNoticeItem(
-					R.layout.list_item_conversation_notice_out, text, r);
+					R.layout.list_item_conversation_notice_out, text,
+					contactName, r);
 		} else {
 			String text = ctx.getString(
 					R.string.blogs_sharing_invitation_received,
 					contactName.getValue(), r.getName());
 			return new ConversationRequestItem(
-					R.layout.list_item_conversation_request, text, BLOG, r);
+					R.layout.list_item_conversation_request, text, contactName,
+					BLOG, r);
 		}
 	}
 
@@ -104,7 +108,8 @@ class ConversationVisitor implements
 						contactName.getValue());
 			}
 			return new ConversationNoticeItem(
-					R.layout.list_item_conversation_notice_out, text, r);
+					R.layout.list_item_conversation_notice_out, text,
+					contactName, r);
 		} else {
 			String text;
 			if (r.wasAccepted()) {
@@ -117,7 +122,8 @@ class ConversationVisitor implements
 						contactName.getValue());
 			}
 			return new ConversationNoticeItem(
-					R.layout.list_item_conversation_notice_in, text, r);
+					R.layout.list_item_conversation_notice_in, text,
+					contactName, r);
 		}
 	}
 
@@ -128,13 +134,15 @@ class ConversationVisitor implements
 			String text = ctx.getString(R.string.forum_invitation_sent,
 					r.getName(), contactName.getValue());
 			return new ConversationNoticeItem(
-					R.layout.list_item_conversation_notice_out, text, r);
+					R.layout.list_item_conversation_notice_out, text,
+					contactName, r);
 		} else {
 			String text = ctx.getString(
 					R.string.forum_invitation_received,
 					contactName.getValue(), r.getName());
 			return new ConversationRequestItem(
-					R.layout.list_item_conversation_request, text, FORUM, r);
+					R.layout.list_item_conversation_request, text, contactName,
+					FORUM, r);
 		}
 	}
 
@@ -153,7 +161,8 @@ class ConversationVisitor implements
 						contactName.getValue());
 			}
 			return new ConversationNoticeItem(
-					R.layout.list_item_conversation_notice_out, text, r);
+					R.layout.list_item_conversation_notice_out, text,
+					contactName, r);
 		} else {
 			String text;
 			if (r.wasAccepted()) {
@@ -166,7 +175,8 @@ class ConversationVisitor implements
 						contactName.getValue());
 			}
 			return new ConversationNoticeItem(
-					R.layout.list_item_conversation_notice_in, text, r);
+					R.layout.list_item_conversation_notice_in, text,
+					contactName, r);
 		}
 	}
 
@@ -178,13 +188,15 @@ class ConversationVisitor implements
 					R.string.groups_invitations_invitation_sent,
 					contactName.getValue(), r.getName());
 			return new ConversationNoticeItem(
-					R.layout.list_item_conversation_notice_out, text, r);
+					R.layout.list_item_conversation_notice_out, text,
+					contactName, r);
 		} else {
 			String text = ctx.getString(
 					R.string.groups_invitations_invitation_received,
 					contactName.getValue(), r.getName());
 			return new ConversationRequestItem(
-					R.layout.list_item_conversation_request, text, GROUP, r);
+					R.layout.list_item_conversation_request, text, contactName,
+					GROUP, r);
 		}
 	}
 
@@ -203,7 +215,8 @@ class ConversationVisitor implements
 						contactName.getValue());
 			}
 			return new ConversationNoticeItem(
-					R.layout.list_item_conversation_notice_out, text, r);
+					R.layout.list_item_conversation_notice_out, text,
+					contactName, r);
 		} else {
 			String text;
 			if (r.wasAccepted()) {
@@ -216,7 +229,8 @@ class ConversationVisitor implements
 						contactName.getValue());
 			}
 			return new ConversationNoticeItem(
-					R.layout.list_item_conversation_notice_in, text, r);
+					R.layout.list_item_conversation_notice_in, text,
+					contactName, r);
 		}
 	}
 
@@ -227,7 +241,8 @@ class ConversationVisitor implements
 			String text = ctx.getString(R.string.introduction_request_sent,
 					contactName.getValue(), name);
 			return new ConversationNoticeItem(
-					R.layout.list_item_conversation_notice_out, text, r);
+					R.layout.list_item_conversation_notice_out, text,
+					contactName, r);
 		} else {
 			String text;
 			if (r.wasAnswered()) {
@@ -243,7 +258,7 @@ class ConversationVisitor implements
 						contactName.getValue(), name);
 			}
 			return new ConversationRequestItem(
-					R.layout.list_item_conversation_request, text,
+					R.layout.list_item_conversation_request, text, contactName,
 					INTRODUCTION, r);
 		}
 	}
@@ -268,7 +283,8 @@ class ConversationVisitor implements
 						introducedAuthor);
 			}
 			return new ConversationNoticeItem(
-					R.layout.list_item_conversation_notice_out, text, r);
+					R.layout.list_item_conversation_notice_out, text,
+					contactName, r);
 		} else {
 			String text;
 			if (r.wasAccepted()) {
@@ -288,7 +304,8 @@ class ConversationVisitor implements
 						introducedAuthor);
 			}
 			return new ConversationNoticeItem(
-					R.layout.list_item_conversation_notice_in, text, r);
+					R.layout.list_item_conversation_notice_in, text,
+					contactName, r);
 		}
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/introduction/IntroductionMessageFragment.java

@@ -35,6 +35,8 @@ import javax.inject.Inject;
 
 import androidx.annotation.Nullable;
 import androidx.appcompat.app.ActionBar;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
 import de.hdodenhof.circleimageview.CircleImageView;
 
 import static android.app.Activity.RESULT_OK;
@@ -46,6 +48,8 @@ import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.briar.android.util.UiUtils.getContactDisplayName;
 import static org.briarproject.briar.android.util.UiUtils.hideSoftKeyboard;
 import static org.briarproject.briar.android.view.AuthorView.setAvatar;
+import static org.briarproject.briar.android.view.TextSendController.SendState;
+import static org.briarproject.briar.android.view.TextSendController.SendState.SENT;
 import static org.briarproject.briar.api.introduction.IntroductionConstants.MAX_INTRODUCTION_TEXT_LENGTH;
 
 @MethodsNotNullByDefault
@@ -201,8 +205,8 @@ public class IntroductionMessageFragment extends BaseFragment
 	}
 
 	@Override
-	public void onSendClick(@Nullable String text,
-			List<AttachmentHeader> headers) {
+	public LiveData<SendState> onSendClick(@Nullable String text,
+			List<AttachmentHeader> headers, long expectedAutoDeleteTimer) {
 		// disable button to prevent accidental double invitations
 		ui.message.setReady(false);
 
@@ -212,6 +216,7 @@ public class IntroductionMessageFragment extends BaseFragment
 		hideSoftKeyboard(ui.message);
 		introductionActivity.setResult(RESULT_OK);
 		introductionActivity.supportFinishAfterTransition();
+		return new MutableLiveData<>(SENT);
 	}
 
 	private void makeIntroduction(Contact c1, Contact c2,
@@ -219,8 +224,7 @@ public class IntroductionMessageFragment extends BaseFragment
 		introductionActivity.runOnDbThread(() -> {
 			// actually make the introduction
 			try {
-				long timestamp = System.currentTimeMillis();
-				introductionManager.makeIntroduction(c1, c2, text, timestamp);
+				introductionManager.makeIntroduction(c1, c2, text);
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 				introductionError();

briar-android/src/main/java/org/briarproject/briar/android/privategroup/creation/CreateGroupControllerImpl.java

@@ -7,6 +7,8 @@ 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.db.Transaction;
+import org.briarproject.bramble.api.db.TransactionManager;
 import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
@@ -15,6 +17,8 @@ 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.autodelete.AutoDeleteManager;
+import org.briarproject.briar.api.conversation.ConversationManager;
 import org.briarproject.briar.api.identity.AuthorManager;
 import org.briarproject.briar.api.privategroup.GroupMessage;
 import org.briarproject.briar.api.privategroup.GroupMessageFactory;
@@ -36,6 +40,8 @@ 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.api.nullsafety.NullSafety.requireNonNull;
 import static org.briarproject.bramble.util.LogUtils.logException;
 
 @Immutable
@@ -44,9 +50,12 @@ class CreateGroupControllerImpl extends ContactSelectorControllerImpl
 		implements CreateGroupController {
 
 	private static final Logger LOG =
-			Logger.getLogger(CreateGroupControllerImpl.class.getName());
+			getLogger(CreateGroupControllerImpl.class.getName());
 
 	private final Executor cryptoExecutor;
+	private final TransactionManager db;
+	private final AutoDeleteManager autoDeleteManager;
+	private final ConversationManager conversationManager;
 	private final ContactManager contactManager;
 	private final IdentityManager identityManager;
 	private final PrivateGroupFactory groupFactory;
@@ -57,17 +66,27 @@ class CreateGroupControllerImpl extends ContactSelectorControllerImpl
 	private final Clock clock;
 
 	@Inject
-	CreateGroupControllerImpl(@DatabaseExecutor Executor dbExecutor,
+	CreateGroupControllerImpl(
+			@DatabaseExecutor Executor dbExecutor,
 			@CryptoExecutor Executor cryptoExecutor,
-			LifecycleManager lifecycleManager, ContactManager contactManager,
-			AuthorManager authorManager, IdentityManager identityManager,
+			TransactionManager db,
+			AutoDeleteManager autoDeleteManager,
+			ConversationManager conversationManager,
+			LifecycleManager lifecycleManager,
+			ContactManager contactManager,
+			AuthorManager authorManager,
+			IdentityManager identityManager,
 			PrivateGroupFactory groupFactory,
 			GroupMessageFactory groupMessageFactory,
 			PrivateGroupManager groupManager,
 			GroupInvitationFactory groupInvitationFactory,
-			GroupInvitationManager groupInvitationManager, Clock clock) {
+			GroupInvitationManager groupInvitationManager,
+			Clock clock) {
 		super(dbExecutor, lifecycleManager, contactManager, authorManager);
 		this.cryptoExecutor = cryptoExecutor;
+		this.db = db;
+		this.autoDeleteManager = autoDeleteManager;
+		this.conversationManager = conversationManager;
 		this.contactManager = contactManager;
 		this.identityManager = identityManager;
 		this.groupFactory = groupFactory;
@@ -131,16 +150,14 @@ class CreateGroupControllerImpl extends ContactSelectorControllerImpl
 			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);
+				db.transaction(false, txn -> {
+					LocalAuthor localAuthor =
+							identityManager.getLocalAuthor(txn);
+					List<InvitationContext> contexts =
+							createInvitationContexts(txn, contactIds);
+					txn.attach(() -> signInvitations(g, localAuthor, contexts,
+							text, handler));
+				});
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 				handler.onException(e);
@@ -148,17 +165,32 @@ class CreateGroupControllerImpl extends ContactSelectorControllerImpl
 		});
 	}
 
+	private List<InvitationContext> createInvitationContexts(Transaction txn,
+			Collection<ContactId> contactIds) throws DbException {
+		List<InvitationContext> contexts = new ArrayList<>();
+		for (ContactId c : contactIds) {
+			try {
+				Contact contact = contactManager.getContact(txn, c);
+				long timestamp = conversationManager
+						.getTimestampForOutgoingMessage(txn, c);
+				long timer = autoDeleteManager.getAutoDeleteTimer(txn, c,
+						timestamp);
+				contexts.add(new InvitationContext(contact, timestamp, timer));
+			} catch (NoSuchContactException e) {
+				// Continue
+			}
+		}
+		return contexts;
+	}
+
 	private void signInvitations(GroupId g, LocalAuthor localAuthor,
-			Collection<Contact> contacts, @Nullable String text,
+			List<InvitationContext> contexts, @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));
+			for (InvitationContext ctx : contexts) {
+				ctx.signature = groupInvitationFactory.signInvitation(
+						ctx.contact, g, ctx.timestamp,
+						localAuthor.getPrivateKey());
 			}
 			sendInvitations(g, contexts, text, handler);
 		});
@@ -169,11 +201,12 @@ class CreateGroupControllerImpl extends ContactSelectorControllerImpl
 			ResultExceptionHandler<Void, DbException> handler) {
 		runOnDbThread(() -> {
 			try {
-				for (InvitationContext context : contexts) {
+				for (InvitationContext ctx : contexts) {
 					try {
 						groupInvitationManager.sendInvitation(g,
-								context.contactId, text, context.timestamp,
-								context.signature);
+								ctx.contact.getId(), text, ctx.timestamp,
+								requireNonNull(ctx.signature),
+								ctx.autoDeleteTimer);
 					} catch (NoSuchContactException e) {
 						// Continue
 					}
@@ -188,15 +221,16 @@ class CreateGroupControllerImpl extends ContactSelectorControllerImpl
 
 	private static class InvitationContext {
 
-		private final ContactId contactId;
-		private final long timestamp;
-		private final byte[] signature;
+		private final Contact contact;
+		private final long timestamp, autoDeleteTimer;
+		@Nullable
+		private byte[] signature = null;
 
-		private InvitationContext(ContactId contactId, long timestamp,
-				byte[] signature) {
-			this.contactId = contactId;
+		private InvitationContext(Contact contact, long timestamp,
+				long autoDeleteTimer) {
+			this.contact = contact;
 			this.timestamp = timestamp;
-			this.signature = signature;
+			this.autoDeleteTimer = autoDeleteTimer;
 		}
 	}
 }

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

@@ -15,6 +15,7 @@ import org.briarproject.briar.android.fragment.BaseFragment;
 import org.briarproject.briar.android.view.LargeTextInputView;
 import org.briarproject.briar.android.view.TextSendController;
 import org.briarproject.briar.android.view.TextSendController.SendListener;
+import org.briarproject.briar.android.view.TextSendController.SendState;
 import org.briarproject.briar.api.attachment.AttachmentHeader;
 
 import java.util.List;
@@ -22,6 +23,10 @@ import java.util.List;
 import androidx.annotation.Nullable;
 import androidx.annotation.StringRes;
 import androidx.annotation.UiThread;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import static org.briarproject.briar.android.view.TextSendController.SendState.SENT;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
@@ -79,13 +84,14 @@ public abstract class BaseMessageFragment extends BaseFragment
 	}
 
 	@Override
-	public void onSendClick(@Nullable String text,
-			List<AttachmentHeader> headers) {
+	public LiveData<SendState> onSendClick(@Nullable String text,
+			List<AttachmentHeader> headers, long expectedAutoDeleteTimer) {
 		// disable button to prevent accidental double actions
 		sendController.setReady(false);
 		message.hideSoftKeyboard();
 
 		listener.onButtonClick(text);
+		return new MutableLiveData<>(SENT);
 	}
 
 	@UiThread

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

@@ -10,11 +10,9 @@ import org.briarproject.bramble.api.db.NoSuchGroupException;
 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.ExceptionHandler;
 import org.briarproject.briar.api.blog.BlogSharingManager;
-import org.briarproject.briar.api.conversation.ConversationManager;
 import org.briarproject.briar.api.identity.AuthorManager;
 
 import java.util.Collection;
@@ -26,6 +24,7 @@ import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
 import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.util.LogUtils.logException;
 
 @Immutable
@@ -34,22 +33,17 @@ class ShareBlogControllerImpl extends ContactSelectorControllerImpl
 		implements ShareBlogController {
 
 	private final static Logger LOG =
-			Logger.getLogger(ShareBlogControllerImpl.class.getName());
+			getLogger(ShareBlogControllerImpl.class.getName());
 
-	private final ConversationManager conversationManager;
 	private final BlogSharingManager blogSharingManager;
-	private final Clock clock;
 
 	@Inject
 	ShareBlogControllerImpl(@DatabaseExecutor Executor dbExecutor,
 			LifecycleManager lifecycleManager, ContactManager contactManager,
 			AuthorManager authorManager,
-			ConversationManager conversationManager,
-			BlogSharingManager blogSharingManager, Clock clock) {
+			BlogSharingManager blogSharingManager) {
 		super(dbExecutor, lifecycleManager, contactManager, authorManager);
-		this.conversationManager = conversationManager;
 		this.blogSharingManager = blogSharingManager;
-		this.clock = clock;
 	}
 
 	@Override
@@ -64,10 +58,7 @@ class ShareBlogControllerImpl extends ContactSelectorControllerImpl
 			try {
 				for (ContactId c : contacts) {
 					try {
-						long time = Math.max(clock.currentTimeMillis(),
-								conversationManager.getGroupCount(c)
-										.getLatestMsgTime() + 1);
-						blogSharingManager.sendInvitation(g, c, text, time);
+						blogSharingManager.sendInvitation(g, c, text);
 					} catch (NoSuchContactException | NoSuchGroupException e) {
 						logException(LOG, WARNING, e);
 					}

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

@@ -10,10 +10,8 @@ import org.briarproject.bramble.api.db.NoSuchGroupException;
 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.ExceptionHandler;
-import org.briarproject.briar.api.conversation.ConversationManager;
 import org.briarproject.briar.api.forum.ForumSharingManager;
 import org.briarproject.briar.api.identity.AuthorManager;
 
@@ -26,6 +24,7 @@ import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
 import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.util.LogUtils.logException;
 
 @Immutable
@@ -34,22 +33,17 @@ class ShareForumControllerImpl extends ContactSelectorControllerImpl
 		implements ShareForumController {
 
 	private final static Logger LOG =
-			Logger.getLogger(ShareForumControllerImpl.class.getName());
+			getLogger(ShareForumControllerImpl.class.getName());
 
-	private final ConversationManager conversationManager;
 	private final ForumSharingManager forumSharingManager;
-	private final Clock clock;
 
 	@Inject
 	ShareForumControllerImpl(@DatabaseExecutor Executor dbExecutor,
 			LifecycleManager lifecycleManager, ContactManager contactManager,
 			AuthorManager authorManager,
-			ConversationManager conversationManager,
-			ForumSharingManager forumSharingManager, Clock clock) {
+			ForumSharingManager forumSharingManager) {
 		super(dbExecutor, lifecycleManager, contactManager, authorManager);
-		this.conversationManager = conversationManager;
 		this.forumSharingManager = forumSharingManager;
-		this.clock = clock;
 	}
 
 	@Override
@@ -64,10 +58,7 @@ class ShareForumControllerImpl extends ContactSelectorControllerImpl
 			try {
 				for (ContactId c : contacts) {
 					try {
-						long time = Math.max(clock.currentTimeMillis(),
-								conversationManager.getGroupCount(c)
-										.getLatestMsgTime() + 1);
-						forumSharingManager.sendInvitation(g, c, text, time);
+						forumSharingManager.sendInvitation(g, c, text);
 					} catch (NoSuchContactException | NoSuchGroupException e) {
 						logException(LOG, WARNING, e);
 					}

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

@@ -19,6 +19,7 @@ import org.briarproject.briar.android.view.BriarRecyclerView;
 import org.briarproject.briar.android.view.TextInputView;
 import org.briarproject.briar.android.view.TextSendController;
 import org.briarproject.briar.android.view.TextSendController.SendListener;
+import org.briarproject.briar.android.view.TextSendController.SendState;
 import org.briarproject.briar.android.view.UnreadMessageButton;
 import org.briarproject.briar.api.attachment.AttachmentHeader;
 
@@ -29,10 +30,13 @@ import javax.annotation.Nullable;
 import androidx.annotation.CallSuper;
 import androidx.annotation.StringRes;
 import androidx.appcompat.app.ActionBar;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
 import androidx.recyclerview.widget.LinearLayoutManager;
 
 import static androidx.recyclerview.widget.RecyclerView.NO_POSITION;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
+import static org.briarproject.briar.android.view.TextSendController.SendState.SENT;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
@@ -231,8 +235,8 @@ public abstract class ThreadListActivity<I extends ThreadItem, A extends ThreadI
 	}
 
 	@Override
-	public void onSendClick(@Nullable String text,
-			List<AttachmentHeader> headers) {
+	public LiveData<SendState> onSendClick(@Nullable String text,
+			List<AttachmentHeader> headers, long expectedAutoDeleteTimer) {
 		if (isNullOrEmpty(text)) throw new AssertionError();
 
 		MessageId replyId = getViewModel().getReplyId();
@@ -241,6 +245,7 @@ public abstract class ThreadListActivity<I extends ThreadItem, A extends ThreadI
 		textInput.clearText();
 		getViewModel().setReplyId(null);
 		updateTextInput();
+		return new MutableLiveData<>(SENT);
 	}
 
 	protected abstract int getMaxTextLength();

briar-android/src/main/java/org/briarproject/briar/android/view/CompositeSendButton.java

@@ -5,6 +5,7 @@ import android.util.AttributeSet;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.widget.FrameLayout;
+import android.widget.ImageView;
 import android.widget.ProgressBar;
 
 import org.briarproject.briar.R;
@@ -19,6 +20,7 @@ import static java.util.Objects.requireNonNull;
 public class CompositeSendButton extends FrameLayout {
 
 	private final AppCompatImageButton sendButton, imageButton;
+	private final ImageView bombBadge;
 	private final ProgressBar progressBar;
 
 	private boolean hasImageSupport = false;
@@ -32,6 +34,7 @@ public class CompositeSendButton extends FrameLayout {
 
 		sendButton = findViewById(R.id.sendButton);
 		imageButton = findViewById(R.id.imageButton);
+		bombBadge = findViewById(R.id.bombBadge);
 		progressBar = findViewById(R.id.progressBar);
 	}
 
@@ -71,6 +74,10 @@ public class CompositeSendButton extends FrameLayout {
 		return hasImageSupport;
 	}
 
+	public void setBombVisible(boolean visible) {
+		bombBadge.setVisibility(visible ? VISIBLE : INVISIBLE);
+	}
+
 	public void showImageButton(boolean showImageButton, boolean sendEnabled) {
 		if (showImageButton) {
 			imageButton.setVisibility(VISIBLE);

briar-android/src/main/java/org/briarproject/briar/android/view/TextAttachmentController.java

@@ -26,7 +26,6 @@ import androidx.annotation.Nullable;
 import androidx.annotation.UiThread;
 import androidx.appcompat.app.AlertDialog.Builder;
 import androidx.customview.view.AbsSavedState;
-import androidx.lifecycle.LifecycleOwner;
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.Observer;
 import androidx.vectordrawable.graphics.drawable.VectorDrawableCompat;
@@ -39,6 +38,7 @@ import static androidx.core.content.ContextCompat.getColor;
 import static androidx.customview.view.AbsSavedState.EMPTY_STATE;
 import static androidx.lifecycle.Lifecycle.State.DESTROYED;
 import static org.briarproject.briar.android.util.UiUtils.resolveColorAttribute;
+import static org.briarproject.briar.android.view.TextSendController.SendState.SENT;
 import static org.briarproject.briar.api.messaging.MessagingConstants.MAX_ATTACHMENTS_PER_MESSAGE;
 
 @UiThread
@@ -52,7 +52,6 @@ public class TextAttachmentController extends TextSendController
 	private final AttachmentManager attachmentManager;
 
 	private final List<Uri> imageUris = new ArrayList<>();
-	private final CharSequence textHint;
 	private boolean loadingUris = false;
 
 	public TextAttachmentController(TextInputView v, ImagePreview imagePreview,
@@ -66,23 +65,44 @@ public class TextAttachmentController extends TextSendController
 
 		sendButton = (CompositeSendButton) compositeSendButton;
 		sendButton.setOnImageClickListener(view -> onImageButtonClicked());
-
-		textHint = textInput.getHint();
 	}
 
 	@Override
 	protected void updateViewState() {
-		textInput.setEnabled(ready && !loadingUris);
-		boolean sendEnabled = ready && !loadingUris &&
-				(!textIsEmpty || canSendEmptyText());
+		super.updateViewState();
 		if (loadingUris) {
 			sendButton.showProgress(true);
 		} else if (imageUris.isEmpty()) {
 			sendButton.showProgress(false);
-			sendButton.showImageButton(textIsEmpty, sendEnabled);
+			sendButton.showImageButton(textIsEmpty, isSendButtonEnabled());
 		} else {
 			sendButton.showProgress(false);
-			sendButton.showImageButton(false, sendEnabled);
+			sendButton.showImageButton(false, isSendButtonEnabled());
+		}
+	}
+
+	@Override
+	protected boolean isTextInputEnabled() {
+		return super.isTextInputEnabled() && !loadingUris;
+	}
+
+	@Override
+	protected boolean isSendButtonEnabled() {
+		return super.isSendButtonEnabled() && !loadingUris;
+	}
+
+	@Override
+	protected boolean isBombVisible() {
+		return super.isBombVisible() && (!textIsEmpty || !imageUris.isEmpty());
+	}
+
+	@Override
+	protected CharSequence getCurrentTextHint() {
+		if (imageUris.isEmpty()) {
+			return super.getCurrentTextHint();
+		} else {
+			Context ctx = textInput.getContext();
+			return ctx.getString(R.string.image_caption_hint);
 		}
 	}
 
@@ -91,11 +111,17 @@ public class TextAttachmentController extends TextSendController
 		if (canSend()) {
 			if (loadingUris) throw new AssertionError();
 			listener.onSendClick(textInput.getText(),
-					attachmentManager.getAttachmentHeadersForSending());
-			reset();
+					attachmentManager.getAttachmentHeadersForSending(),
+					expectedTimer).observe(listener, this::onSendStateChanged);
 		}
 	}
 
+	@Override
+	protected void onSendStateChanged(SendState sendState) {
+		super.onSendStateChanged(sendState);
+		if (sendState == SENT) reset();
+	}
+
 	@Override
 	protected boolean canSendEmptyText() {
 		return !imageUris.isEmpty();
@@ -154,6 +180,7 @@ public class TextAttachmentController extends TextSendController
 	private void onNewUris(boolean restart, List<Uri> newUris) {
 		if (newUris.isEmpty()) return;
 		if (loadingUris) throw new AssertionError();
+		if (textIsEmpty) onStartingMessage();
 		loadingUris = true;
 		if (newUris.size() > MAX_ATTACHMENTS_PER_MESSAGE) {
 			newUris = newUris.subList(0, MAX_ATTACHMENTS_PER_MESSAGE);
@@ -161,7 +188,6 @@ public class TextAttachmentController extends TextSendController
 		}
 		imageUris.addAll(newUris);
 		updateViewState();
-		textInput.setHint(R.string.image_caption_hint);
 		List<ImagePreviewItem> items = ImagePreviewItem.fromUris(imageUris);
 		imagePreview.showPreview(items);
 		// store attachments and show preview when successful
@@ -207,8 +233,6 @@ public class TextAttachmentController extends TextSendController
 	}
 
 	private void reset() {
-		// restore hint
-		textInput.setHint(textHint);
 		// hide image layout
 		imagePreview.setVisibility(GONE);
 		// reset image URIs
@@ -303,7 +327,7 @@ public class TextAttachmentController extends TextSendController
 	}
 
 	@UiThread
-	public interface AttachmentListener extends SendListener, LifecycleOwner {
+	public interface AttachmentListener extends SendListener {
 
 		void onAttachImage(Intent intent);
 

briar-android/src/main/java/org/briarproject/briar/android/view/TextSendController.java

@@ -1,7 +1,9 @@
 package org.briarproject.briar.android.view;
 
+import android.content.Context;
 import android.os.Parcelable;
 import android.view.View;
+import android.widget.Toast;
 
 import com.google.android.material.snackbar.Snackbar;
 
@@ -12,11 +14,20 @@ import org.briarproject.briar.api.attachment.AttachmentHeader;
 
 import java.util.List;
 
+import androidx.annotation.CallSuper;
 import androidx.annotation.Nullable;
 import androidx.annotation.UiThread;
+import androidx.appcompat.app.AlertDialog;
+import androidx.lifecycle.LifecycleOwner;
+import androidx.lifecycle.LiveData;
 
+import static android.widget.Toast.LENGTH_LONG;
 import static com.google.android.material.snackbar.Snackbar.LENGTH_SHORT;
 import static java.util.Collections.emptyList;
+import static org.briarproject.briar.android.view.TextSendController.SendState.ERROR;
+import static org.briarproject.briar.android.view.TextSendController.SendState.SENT;
+import static org.briarproject.briar.android.view.TextSendController.SendState.UNEXPECTED_TIMER;
+import static org.briarproject.briar.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
 
 @UiThread
 @NotNullByDefault
@@ -26,8 +37,12 @@ public class TextSendController implements TextInputListener {
 	protected final View compositeSendButton;
 	protected final SendListener listener;
 
-	protected boolean ready = true, textIsEmpty = true;
+	protected boolean textIsEmpty = true;
+	private boolean ready = true;
+	private long currentTimer = NO_AUTO_DELETE_TIMER;
+	protected long expectedTimer = NO_AUTO_DELETE_TIMER;
 
+	private final CharSequence defaultHint;
 	private final boolean allowEmptyText;
 
 	public TextSendController(TextInputView v, SendListener listener,
@@ -36,31 +51,91 @@ public class TextSendController implements TextInputListener {
 		this.compositeSendButton.setOnClickListener(view -> onSendEvent());
 		this.listener = listener;
 		this.textInput = v.getEmojiTextInputView();
+		this.defaultHint = textInput.getHint();
 		this.allowEmptyText = allowEmptyText;
 	}
 
 	@Override
 	public void onTextIsEmptyChanged(boolean isEmpty) {
 		textIsEmpty = isEmpty;
+		if (!isEmpty) onStartingMessage();
 		updateViewState();
 	}
 
 	@Override
 	public void onSendEvent() {
 		if (canSend()) {
-			listener.onSendClick(textInput.getText(), emptyList());
+			listener.onSendClick(textInput.getText(), emptyList(),
+					expectedTimer).observe(listener, this::onSendStateChanged);
 		}
 	}
 
+	@CallSuper
+	protected void onSendStateChanged(SendState sendState) {
+		if (sendState == SENT) {
+			textInput.clearText();
+		} else if (sendState == UNEXPECTED_TIMER) {
+			boolean enabled = expectedTimer == NO_AUTO_DELETE_TIMER;
+			showTimerChangedDialog(enabled);
+		} else if (sendState == ERROR) {
+			Toast.makeText(textInput.getContext(), R.string.message_error,
+					LENGTH_LONG).show();
+		}
+	}
+
+	/**
+	 * Call whenever the user starts a new message,
+	 * either by entering text or adding an attachment.
+	 * This updates the expected auto-delete timer to the current value.
+	 */
+	protected void onStartingMessage() {
+		expectedTimer = currentTimer;
+	}
+
 	public void setReady(boolean ready) {
 		this.ready = ready;
 		updateViewState();
 	}
 
+	/**
+	 * Sets the current auto delete timer and updates the UI accordingly.
+	 */
+	public void setAutoDeleteTimer(long timer) {
+		currentTimer = timer;
+		updateViewState();
+	}
+
+	@CallSuper
 	protected void updateViewState() {
-		textInput.setEnabled(ready);
-		compositeSendButton
-				.setEnabled(ready && (!textIsEmpty || canSendEmptyText()));
+		textInput.setEnabled(isTextInputEnabled());
+		textInput.setHint(getCurrentTextHint());
+		compositeSendButton.setEnabled(isSendButtonEnabled());
+		if (compositeSendButton instanceof CompositeSendButton) {
+			CompositeSendButton sendButton =
+					(CompositeSendButton) compositeSendButton;
+			sendButton.setBombVisible(isBombVisible());
+		}
+	}
+
+	protected boolean isTextInputEnabled() {
+		return ready;
+	}
+
+	protected boolean isSendButtonEnabled() {
+		return ready && (!textIsEmpty || canSendEmptyText());
+	}
+
+	protected boolean isBombVisible() {
+		return currentTimer != NO_AUTO_DELETE_TIMER;
+	}
+
+	protected CharSequence getCurrentTextHint() {
+		if (currentTimer == NO_AUTO_DELETE_TIMER) {
+			return defaultHint;
+		} else {
+			Context ctx = textInput.getContext();
+			return ctx.getString(R.string.message_hint_auto_delete);
+		}
 	}
 
 	protected final boolean canSend() {
@@ -76,6 +151,23 @@ public class TextSendController implements TextInputListener {
 		return allowEmptyText;
 	}
 
+	private void showTimerChangedDialog(boolean enabled) {
+		Context ctx = textInput.getContext();
+		int message =
+				enabled ? R.string.auto_delete_changed_warning_message_enabled :
+						R.string.auto_delete_changed_warning_message_disabled;
+		new AlertDialog.Builder(ctx, R.style.BriarDialogTheme)
+				.setTitle(R.string.auto_delete_changed_warning_title)
+				.setMessage(message)
+				.setPositiveButton(R.string.auto_delete_changed_warning_send,
+						(dialog, which) -> {
+							expectedTimer = currentTimer;
+							onSendEvent();
+						})
+				.setNegativeButton(R.string.cancel, null)
+				.show();
+	}
+
 	@Nullable
 	public Parcelable onSaveInstanceState(@Nullable Parcelable superState) {
 		return superState;
@@ -86,9 +178,11 @@ public class TextSendController implements TextInputListener {
 		return state;
 	}
 
-	@UiThread
-	public interface SendListener {
-		void onSendClick(@Nullable String text, List<AttachmentHeader> headers);
+	public enum SendState {SENT, ERROR, UNEXPECTED_TIMER}
+
+	public interface SendListener extends LifecycleOwner {
+		LiveData<SendState> onSendClick(@Nullable String text,
+				List<AttachmentHeader> headers, long expectedAutoDeleteTimer);
 	}
 
 }

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

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+	android:width="16dp"
+	android:height="16dp"
+	android:viewportWidth="24"
+	android:viewportHeight="24">
+	<path
+		android:fillColor="#FFFFFF"
+		android:pathData="M11.25,6A3.25,3.25 0 0,1 14.5,2.75A3.25,3.25 0 0,1 17.75,6C17.75,6.42 18.08,6.75 18.5,6.75C18.92,6.75 19.25,6.42 19.25,6V5.25H20.75V6A2.25,2.25 0 0,1 18.5,8.25A2.25,2.25 0 0,1 16.25,6A1.75,1.75 0 0,0 14.5,4.25A1.75,1.75 0 0,0 12.75,6H14V7.29C16.89,8.15 19,10.83 19,14A7,7 0 0,1 12,21A7,7 0 0,1 5,14C5,10.83 7.11,8.15 10,7.29V6H11.25M22,6H24V7H22V6M19,4V2H20V4H19M20.91,4.38L22.33,2.96L23.04,3.67L21.62,5.09L20.91,4.38Z" />
+</vector>

briar-android/src/main/res/layout/fragment_conversation_settings.xml

@@ -0,0 +1,71 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:app="http://schemas.android.com/apk/res-auto"
+	xmlns:tools="http://schemas.android.com/tools"
+	android:layout_width="match_parent"
+	android:layout_height="match_parent">
+
+	<androidx.appcompat.widget.Toolbar
+		android:id="@+id/toolbar"
+		style="@style/BriarToolbar"
+		android:layout_width="match_parent"
+		android:layout_height="wrap_content"
+		app:layout_constraintEnd_toEndOf="parent"
+		app:layout_constraintStart_toStartOf="parent"
+		app:layout_constraintTop_toTopOf="parent"
+		app:navigationIcon="@drawable/abc_ic_ab_back_material"
+		app:title="@string/disappearing_messages_title" />
+
+	<ScrollView
+		android:layout_width="match_parent"
+		android:layout_height="0dp"
+		android:paddingHorizontal="@dimen/margin_large"
+		app:layout_constraintBottom_toBottomOf="parent"
+		app:layout_constraintEnd_toEndOf="parent"
+		app:layout_constraintStart_toStartOf="parent"
+		app:layout_constraintTop_toBottomOf="@id/toolbar">
+
+		<androidx.constraintlayout.widget.ConstraintLayout
+			android:layout_width="match_parent"
+			android:layout_height="wrap_content">
+
+			<ImageView
+				android:id="@+id/imageViewBomb"
+				android:layout_width="64dp"
+				android:layout_height="64dp"
+				android:layout_marginTop="16dp"
+				app:layout_constraintEnd_toEndOf="parent"
+				app:layout_constraintStart_toStartOf="parent"
+				app:layout_constraintTop_toTopOf="parent"
+				app:srcCompat="@drawable/ic_bomb"
+				app:tint="?attr/colorControlNormal"
+				tools:ignore="ContentDescription" />
+
+			<androidx.appcompat.widget.SwitchCompat
+				android:id="@+id/switchDisappearingMessages"
+				android:layout_width="wrap_content"
+				android:layout_height="wrap_content"
+				android:layout_marginTop="16dp"
+				android:enabled="false"
+				android:text="@string/disappearing_messages_summary"
+				app:layout_constraintEnd_toEndOf="parent"
+				app:layout_constraintStart_toStartOf="parent"
+				app:layout_constraintTop_toBottomOf="@+id/imageViewBomb" />
+
+			<TextView
+				android:id="@+id/buttonLearnMore"
+				android:layout_width="wrap_content"
+				android:layout_height="wrap_content"
+				android:layout_marginTop="@dimen/margin_large"
+				android:clickable="true"
+				android:focusable="true"
+				android:text="@string/learn_more"
+				android:textColor="@color/briar_text_link"
+				app:layout_constraintStart_toStartOf="parent"
+				app:layout_constraintTop_toBottomOf="@+id/switchDisappearingMessages" />
+
+		</androidx.constraintlayout.widget.ConstraintLayout>
+
+	</ScrollView>
+
+</androidx.constraintlayout.widget.ConstraintLayout>

briar-android/src/main/res/layout/fragment_conversation_settings_learn_more.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:app="http://schemas.android.com/apk/res-auto"
+	android:layout_width="match_parent"
+	android:layout_height="match_parent"
+	android:paddingHorizontal="?dialogPreferredPadding">
+
+	<TextView
+		android:id="@+id/textView"
+		android:layout_width="wrap_content"
+		android:layout_height="wrap_content"
+		android:text="@string/disappearing_messages_explanation_long"
+		android:textColor="?android:attr/textColorSecondary"
+		app:layout_constraintBottom_toBottomOf="parent"
+		app:layout_constraintEnd_toEndOf="parent"
+		app:layout_constraintStart_toStartOf="parent"
+		app:layout_constraintTop_toTopOf="parent" />
+
+</ScrollView>

briar-android/src/main/res/layout/list_item_conversation_msg_image.xml

@@ -1,4 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
+
+<!-- This layout is only used indirectly by cloning and setting its ConstraintSet -->
 <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
 	xmlns:app="http://schemas.android.com/apk/res-auto"
 	xmlns:tools="http://schemas.android.com/tools"
@@ -68,6 +70,16 @@
 			android:layout_height="wrap_content"
 			tools:text="Dec 24, 13:37" />
 
+		<ImageView
+			android:id="@+id/bomb"
+			android:layout_width="wrap_content"
+			android:layout_height="wrap_content"
+			android:layout_marginStart="4dp"
+			android:layout_marginEnd="4dp"
+			app:srcCompat="@drawable/ic_bomb"
+			app:tint="?android:attr/textColorSecondary"
+			tools:ignore="ContentDescription" />
+
 	</LinearLayout>
 
 </androidx.constraintlayout.widget.ConstraintLayout>

briar-android/src/main/res/layout/list_item_conversation_msg_image_text.xml

@@ -1,4 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
+
+<!-- This layout is only used indirectly by cloning and setting its ConstraintSet -->
 <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
 	xmlns:app="http://schemas.android.com/apk/res-auto"
 	xmlns:tools="http://schemas.android.com/tools"
@@ -58,7 +60,8 @@
 		app:layout_constraintEnd_toEndOf="parent"
 		app:layout_constraintHorizontal_bias="1.0"
 		app:layout_constraintStart_toStartOf="parent"
-		app:layout_constraintTop_toBottomOf="@+id/text">
+		app:layout_constraintTop_toBottomOf="@+id/text"
+		tools:ignore="UseCompoundDrawables">
 
 		<TextView
 			android:id="@+id/time"
@@ -67,6 +70,16 @@
 			android:layout_height="wrap_content"
 			tools:text="Dec 24, 13:37" />
 
+		<ImageView
+			android:id="@+id/bomb"
+			android:layout_width="wrap_content"
+			android:layout_height="wrap_content"
+			android:layout_marginStart="4dp"
+			android:layout_marginEnd="4dp"
+			app:srcCompat="@drawable/ic_bomb"
+			app:tint="?android:attr/textColorSecondary"
+			tools:ignore="ContentDescription" />
+
 	</LinearLayout>
 
 </androidx.constraintlayout.widget.ConstraintLayout>

briar-android/src/main/res/layout/list_item_conversation_msg_in.xml

@@ -1,14 +1,19 @@
 <?xml version="1.0" encoding="utf-8"?>
-<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 	android:layout_width="match_parent"
 	android:layout_height="wrap_content"
-	android:background="@drawable/list_item_background_selectable">
+	android:background="@drawable/list_item_background_selectable"
+	android:orientation="vertical">
 
 	<!--
-	We need to wrap the actual layout, because
-	* we want to clone the ConstraintLayout's constraints in the ViewHolder
-	* we want to have a selectable frame around the message bubble
+	We need to wrap the actual layout, because we want to
+	* clone the ConstraintLayout's constraints in the ViewHolder
+	* have a selectable frame around the message bubble
+	* insert a top notice with its own independent width
 	-->
+
+	<include layout="@layout/list_item_conversation_top_notice_in" />
+
 	<include layout="@layout/list_item_conversation_msg_in_content" />
 
-</FrameLayout>
+</LinearLayout>

briar-android/src/main/res/layout/list_item_conversation_msg_in_content.xml

@@ -1,4 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
+
+<!-- This layout gets wrapped in *_msg_in.xml -->
 <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
 	xmlns:app="http://schemas.android.com/apk/res-auto"
 	xmlns:tools="http://schemas.android.com/tools"
@@ -68,6 +70,17 @@
 			android:layout_height="wrap_content"
 			tools:text="Dec 24, 13:37" />
 
+		<ImageView
+			android:id="@+id/bomb"
+			android:layout_width="wrap_content"
+			android:layout_height="wrap_content"
+			android:layout_marginStart="4dp"
+			android:layout_marginLeft="4dp"
+			app:srcCompat="@drawable/ic_bomb"
+			app:tint="?android:attr/textColorSecondary"
+			tools:ignore="ContentDescription"
+			tools:visibility="visible" />
+
 	</LinearLayout>
 
 </androidx.constraintlayout.widget.ConstraintLayout>

briar-android/src/main/res/layout/list_item_conversation_msg_out.xml

@@ -1,10 +1,14 @@
 <?xml version="1.0" encoding="utf-8"?>
-<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 	xmlns:app="http://schemas.android.com/apk/res-auto"
 	xmlns:tools="http://schemas.android.com/tools"
 	android:layout_width="match_parent"
 	android:layout_height="wrap_content"
-	android:background="@drawable/list_item_background_selectable">
+	android:background="@drawable/list_item_background_selectable"
+	android:orientation="vertical"
+	android:paddingTop="@dimen/message_bubble_margin">
+
+	<include layout="@layout/list_item_conversation_top_notice_out" />
 
 	<androidx.constraintlayout.widget.ConstraintLayout
 		android:id="@+id/layout"
@@ -73,15 +77,26 @@
 				style="@style/TextMessage.Timestamp"
 				android:layout_width="wrap_content"
 				android:layout_height="wrap_content"
-				android:layout_marginEnd="6dp"
-				android:layout_marginRight="6dp"
+				android:layout_marginEnd="4dp"
+				android:layout_marginRight="4dp"
 				android:textColor="@color/private_message_date_inverse"
 				tools:text="Dec 24, 13:37" />
 
+			<ImageView
+				android:id="@+id/bomb"
+				android:layout_width="wrap_content"
+				android:layout_height="wrap_content"
+				android:layout_marginEnd="4dp"
+				android:layout_marginRight="4dp"
+				app:srcCompat="@drawable/ic_bomb"
+				app:tint="@color/private_message_date_inverse"
+				tools:ignore="ContentDescription" />
+
 			<ImageView
 				android:id="@+id/status"
 				android:layout_width="wrap_content"
 				android:layout_height="wrap_content"
+				app:tint="@color/private_message_date_inverse"
 				tools:ignore="ContentDescription"
 				tools:src="@drawable/message_delivered" />
 
@@ -89,4 +104,4 @@
 
 	</androidx.constraintlayout.widget.ConstraintLayout>
 
-</FrameLayout>
+</LinearLayout>

briar-android/src/main/res/layout/list_item_conversation_notice_in.xml

@@ -5,8 +5,9 @@
 	android:layout_width="match_parent"
 	android:layout_height="wrap_content"
 	android:background="@drawable/list_item_background_selectable"
-	android:orientation="vertical"
-	android:paddingTop="@dimen/message_bubble_margin">
+	android:orientation="vertical">
+
+	<include layout="@layout/list_item_conversation_top_notice_in" />
 
 	<com.vanniktech.emoji.EmojiTextView
 		android:id="@+id/msgText"
@@ -15,11 +16,13 @@
 		android:layout_height="wrap_content"
 		android:layout_marginStart="@dimen/message_bubble_margin_tail"
 		android:layout_marginLeft="@dimen/message_bubble_margin_tail"
+		android:layout_marginTop="@dimen/message_bubble_margin"
 		android:layout_marginEnd="@dimen/message_bubble_margin_non_tail"
 		android:layout_marginRight="@dimen/message_bubble_margin_non_tail"
 		android:background="@drawable/msg_in_top"
 		android:elevation="@dimen/message_bubble_elevation"
-		tools:text="Short message" />
+		tools:text="Short message"
+		tools:visibility="visible" />
 
 	<androidx.constraintlayout.widget.ConstraintLayout
 		android:id="@+id/layout"
@@ -48,10 +51,28 @@
 			android:layout_width="wrap_content"
 			android:layout_height="wrap_content"
 			android:layout_marginTop="@dimen/message_bubble_timestamp_margin"
-			app:layout_constraintEnd_toEndOf="@+id/text"
+			app:layout_constraintEnd_toStartOf="@+id/bomb"
+			app:layout_constraintHorizontal_bias="1.0"
+			app:layout_constraintHorizontal_chainStyle="packed"
+			app:layout_constraintStart_toStartOf="parent"
 			app:layout_constraintTop_toBottomOf="@+id/text"
 			tools:text="Dec 24, 13:37" />
 
+		<ImageView
+			android:id="@+id/bomb"
+			android:layout_width="wrap_content"
+			android:layout_height="wrap_content"
+			android:layout_marginStart="4dp"
+			android:layout_marginLeft="4dp"
+			android:layout_marginTop="@dimen/message_bubble_timestamp_margin"
+			app:layout_constraintEnd_toEndOf="@+id/text"
+			app:layout_constraintStart_toEndOf="@+id/time"
+			app:layout_constraintTop_toBottomOf="@+id/text"
+			app:srcCompat="@drawable/ic_bomb"
+			app:tint="?android:attr/textColorSecondary"
+			tools:ignore="ContentDescription"
+			tools:visibility="visible" />
+
 	</androidx.constraintlayout.widget.ConstraintLayout>
 
-</LinearLayout>
+</LinearLayout>

briar-android/src/main/res/layout/list_item_conversation_notice_out.xml

@@ -8,6 +8,8 @@
 	android:orientation="vertical"
 	android:paddingTop="@dimen/message_bubble_margin">
 
+	<include layout="@layout/list_item_conversation_top_notice_out" />
+
 	<com.vanniktech.emoji.EmojiTextView
 		android:id="@+id/msgText"
 		style="@style/TextMessage"
@@ -15,12 +17,14 @@
 		android:layout_height="wrap_content"
 		android:layout_marginStart="@dimen/message_bubble_margin_non_tail"
 		android:layout_marginLeft="@dimen/message_bubble_margin_non_tail"
+		android:layout_marginTop="@dimen/message_bubble_margin"
 		android:layout_marginEnd="@dimen/message_bubble_margin_tail"
 		android:layout_marginRight="@dimen/message_bubble_margin_tail"
 		android:background="@drawable/msg_out_top"
 		android:elevation="@dimen/message_bubble_elevation"
 		android:textColor="@color/briar_text_primary_inverse"
-		tools:text="This is a long long long message that spans over several lines.\n\nIt ends here." />
+		tools:text="This is a long long long message that spans over several lines.\n\nIt ends here."
+		tools:visibility="visible" />
 
 	<androidx.constraintlayout.widget.ConstraintLayout
 		android:id="@+id/layout"
@@ -56,14 +60,28 @@
 			tools:text="Dec 24, 13:37" />
 
 		<ImageView
-			android:id="@+id/status"
+			android:id="@+id/bomb"
 			android:layout_width="wrap_content"
 			android:layout_height="wrap_content"
-			android:layout_marginStart="@dimen/margin_medium"
-			android:layout_marginLeft="@dimen/margin_medium"
+			android:layout_marginStart="4dp"
+			android:layout_marginLeft="4dp"
 			app:layout_constraintBottom_toBottomOf="@+id/time"
 			app:layout_constraintStart_toEndOf="@+id/time"
 			app:layout_constraintTop_toTopOf="@+id/time"
+			app:srcCompat="@drawable/ic_bomb"
+			app:tint="@color/private_message_date_inverse"
+			tools:ignore="ContentDescription" />
+
+		<ImageView
+			android:id="@+id/status"
+			android:layout_width="wrap_content"
+			android:layout_height="wrap_content"
+			android:layout_marginStart="4dp"
+			android:layout_marginLeft="4dp"
+			app:layout_constraintBottom_toBottomOf="@+id/time"
+			app:layout_constraintStart_toEndOf="@+id/bomb"
+			app:layout_constraintTop_toTopOf="@+id/time"
+			app:tint="@color/private_message_date_inverse"
 			tools:ignore="ContentDescription"
 			tools:src="@drawable/message_delivered" />
 

briar-android/src/main/res/layout/list_item_conversation_request.xml

@@ -5,8 +5,9 @@
 	android:layout_width="match_parent"
 	android:layout_height="wrap_content"
 	android:background="@drawable/list_item_background_selectable"
-	android:orientation="vertical"
-	android:paddingTop="@dimen/message_bubble_margin">
+	android:orientation="vertical">
+
+	<include layout="@layout/list_item_conversation_top_notice_in" />
 
 	<com.vanniktech.emoji.EmojiTextView
 		android:id="@+id/msgText"
@@ -15,6 +16,7 @@
 		android:layout_height="wrap_content"
 		android:layout_marginStart="@dimen/message_bubble_margin_tail"
 		android:layout_marginLeft="@dimen/message_bubble_margin_tail"
+		android:layout_marginTop="@dimen/message_bubble_margin"
 		android:layout_marginEnd="@dimen/message_bubble_margin_non_tail"
 		android:layout_marginRight="@dimen/message_bubble_margin_non_tail"
 		android:background="@drawable/msg_in_top"
@@ -68,10 +70,27 @@
 			style="@style/TextMessage.Timestamp"
 			android:layout_width="wrap_content"
 			android:layout_height="wrap_content"
-			app:layout_constraintEnd_toEndOf="parent"
+			app:layout_constraintEnd_toStartOf="@+id/bomb"
+			app:layout_constraintHorizontal_bias="1.0"
+			app:layout_constraintHorizontal_chainStyle="packed"
+			app:layout_constraintStart_toStartOf="parent"
 			app:layout_constraintTop_toBottomOf="@+id/acceptButton"
 			tools:text="Dec 24, 13:37" />
 
+		<ImageView
+			android:id="@+id/bomb"
+			android:layout_width="wrap_content"
+			android:layout_height="wrap_content"
+			android:layout_marginStart="4dp"
+			android:layout_marginLeft="4dp"
+			app:layout_constraintEnd_toEndOf="parent"
+			app:layout_constraintStart_toEndOf="@+id/time"
+			app:layout_constraintTop_toBottomOf="@+id/acceptButton"
+			app:srcCompat="@drawable/ic_bomb"
+			app:tint="?android:attr/textColorSecondary"
+			tools:ignore="ContentDescription"
+			tools:visibility="visible" />
+
 	</androidx.constraintlayout.widget.ConstraintLayout>
 
-</LinearLayout>
+</LinearLayout>

briar-android/src/main/res/layout/list_item_conversation_top_notice_in.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.vanniktech.emoji.EmojiTextView xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:tools="http://schemas.android.com/tools"
+	android:id="@+id/topNotice"
+	style="@style/TextMessage.Notice"
+	android:layout_width="wrap_content"
+	android:layout_height="wrap_content"
+	android:layout_marginStart="@dimen/message_bubble_margin_tail"
+	android:layout_marginLeft="@dimen/message_bubble_margin_tail"
+	android:layout_marginTop="@dimen/message_bubble_margin"
+	android:layout_marginEnd="@dimen/message_bubble_margin_non_tail"
+	android:layout_marginRight="@dimen/message_bubble_margin_non_tail"
+	android:layout_marginBottom="@dimen/message_bubble_margin"
+	android:background="@drawable/notice_in"
+	android:elevation="@dimen/message_bubble_elevation"
+	android:paddingBottom="@dimen/message_bubble_padding_top"
+	android:textIsSelectable="false"
+	android:visibility="gone"
+	tools:text="@string/auto_delete_msg_contact_enabled"
+	tools:visibility="visible" />

briar-android/src/main/res/layout/list_item_conversation_top_notice_out.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.vanniktech.emoji.EmojiTextView xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:tools="http://schemas.android.com/tools"
+	android:id="@+id/topNotice"
+	style="@style/TextMessage.Notice"
+	android:layout_width="wrap_content"
+	android:layout_height="wrap_content"
+	android:layout_gravity="end|right"
+	android:layout_marginStart="@dimen/message_bubble_margin_non_tail"
+	android:layout_marginLeft="@dimen/message_bubble_margin_non_tail"
+	android:layout_marginEnd="@dimen/message_bubble_margin_tail"
+	android:layout_marginRight="@dimen/message_bubble_margin_tail"
+	android:layout_marginBottom="@dimen/message_bubble_margin"
+	android:background="@drawable/notice_out"
+	android:elevation="@dimen/message_bubble_elevation"
+	android:paddingBottom="@dimen/message_bubble_padding_top"
+	android:textColor="@color/private_message_date_inverse"
+	android:textIsSelectable="false"
+	android:visibility="gone"
+	tools:showIn="@layout/list_item_conversation_msg_out"
+	tools:text="@string/auto_delete_msg_you_enabled"
+	tools:visibility="visible" />

briar-android/src/main/res/layout/view_composite_send_button.xml

@@ -37,6 +37,18 @@
 		app:srcCompat="@drawable/social_send_now_white"
 		app:tint="@color/briar_accent" />
 
+	<ImageView
+		android:id="@+id/bombBadge"
+		android:layout_width="wrap_content"
+		android:layout_height="wrap_content"
+		android:layout_gravity="end|bottom"
+		android:layout_margin="3dp"
+		android:contentDescription="@string/auto_delete_msg_contact_enabled"
+		android:visibility="invisible"
+		app:srcCompat="@drawable/ic_bomb"
+		app:tint="@color/briar_accent"
+		tools:visibility="visible" />
+
 	<ProgressBar
 		android:id="@+id/progressBar"
 		android:layout_width="@dimen/text_input_height"

briar-android/src/main/res/menu/conversation_actions.xml

@@ -1,30 +1,37 @@
 <?xml version="1.0" encoding="utf-8"?>
-<menu
-	xmlns:android="http://schemas.android.com/apk/res/android"
-	xmlns:app="http://schemas.android.com/apk/res-auto">
+<menu xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:app="http://schemas.android.com/apk/res-auto"
+	xmlns:tools="http://schemas.android.com/tools">
 
 	<item
 		android:id="@+id/action_introduction"
+		android:enabled="false"
 		android:icon="@drawable/introduction_white"
 		android:title="@string/introduction_menu_item"
-		android:enabled="false"
-		app:showAsAction="never"/>
+		app:showAsAction="never" />
 
 	<item
 		android:id="@+id/action_set_alias"
-		android:title="@string/set_contact_alias"
 		android:enabled="false"
-		app:showAsAction="never"/>
+		android:title="@string/set_contact_alias"
+		app:showAsAction="never" />
+
+	<item
+		android:id="@+id/action_conversation_settings"
+		android:title="@string/menu_item_disappearing_messages"
+		android:visible="false"
+		app:showAsAction="never"
+		tools:visible="true" />
 
 	<item
 		android:id="@+id/action_delete_all_messages"
 		android:title="@string/delete_all_messages"
-		app:showAsAction="never"/>
+		app:showAsAction="never" />
 
 	<item
 		android:id="@+id/action_social_remove_person"
 		android:icon="@drawable/action_delete_white"
 		android:title="@string/delete_contact"
-		app:showAsAction="never"/>
+		app:showAsAction="never" />
 
-</menu>
+</menu>

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

@@ -157,7 +157,9 @@
 	<string name="no_contacts_action">Tap the + icon to add a contact</string>
 	<string name="date_no_private_messages">No messages.</string>
 	<string name="no_private_messages">No messages to show</string>
-	<string name="message_hint">Type message</string>
+	<string name="message_hint">New message</string>
+	<string name="message_hint_auto_delete">New disappearing message</string>
+	<string name="message_error">Error sending message</string>
 	<string name="image_caption_hint">Add a caption (optional)</string>
 	<string name="image_attach">Attach image</string>
 	<string name="image_attach_error">Could not attach image(s)</string>
@@ -165,6 +167,20 @@
 	<string name="image_attach_error_invalid_mime_type">Image format unsupported: %s</string>
 	<string name="set_contact_alias">Change contact name</string>
 	<string name="set_contact_alias_hint">Contact name</string>
+	<string name="menu_item_disappearing_messages">Disappearing messages</string>
+	<!-- The placeholder at the end will add "Tap to learn more." -->
+	<string name="auto_delete_msg_you_enabled">Your messages will disappear after 7 days. %1$s</string>
+	<!-- The placeholder at the end will add "Tap to learn more." -->
+	<string name="auto_delete_msg_you_disabled">Your messages will not disappear. %1$s</string>
+	<!-- The second placeholder at the end will add "Tap to learn more." -->
+	<string name="auto_delete_msg_contact_enabled">%1$s\'s messages will disappear after 7 days. %2$s</string>
+	<!-- The second placeholder at the end will add "Tap to learn more." -->
+	<string name="auto_delete_msg_contact_disabled">%1$s\'s messages will not disappear. %2$s</string>
+	<string name="tap_to_learn_more">Tap to learn more.</string>
+	<string name="auto_delete_changed_warning_title">Disappearing messages changed</string>
+	<string name="auto_delete_changed_warning_message_enabled">Since you started composing your message, disappearing messages have been enabled.</string>
+	<string name="auto_delete_changed_warning_message_disabled">Since you started composing your message, disappearing messages have been disabled.</string>
+	<string name="auto_delete_changed_warning_send">Send anyway</string>
 	<string name="delete_all_messages">Delete all messages</string>
 	<string name="dialog_title_delete_all_messages">Confirm Message Deletion</string>
 	<string name="dialog_message_delete_all_messages">Are you sure that you want to delete all messages?</string>
@@ -551,6 +567,19 @@
 	<string name="choose_ringtone_title">Choose ringtone</string>
 	<string name="cannot_load_ringtone">Cannot load ringtone</string>
 
+	<!-- Conversation Settings -->
+	<string name="disappearing_messages_title">Disappearing messages</string>
+	<string name="disappearing_messages_explanation_long">Turning on this setting will make new
+		messages in this conversation automatically disappear 7\u00A0days after being received.
+		This applies to messages you send to your contact as well as messages your contact sends to you.
+		Your contact can also change this setting for the both of you.
+		\n\nMessages that will disappear are marked with a bomb icon.
+		\n\nKeep in mind that recipients can still make copies of the messages you send.
+		\n\nIf you change this setting, it will apply to your messages immediately and to your
+		contact\'s messages once they receive your next message.</string>
+	<string name="learn_more">Learn more</string>
+	<string name="disappearing_messages_summary">Make future messages in this conversation automatically disappear 7\u00A0days after being received.</string>
+
 	<!-- Settings Feedback -->
 	<string name="feedback_settings_title">Feedback</string>
 	<string name="send_feedback">Send feedback</string>

briar-android/src/main/res/values/themes.xml

@@ -43,6 +43,16 @@
 		<item name="android:filterTouchesWhenObscured">true</item>
 	</style>
 
+	<style name="BriarFullScreenDialogTheme" parent="BriarDialogTheme">
+		<item name="android:windowIsFloating">false</item>
+		<item name="android:windowAnimationStyle">@style/FullScreenDialogAnimation</item>
+	</style>
+
+	<style name="FullScreenDialogAnimation" parent="@android:style/Animation.Activity">
+		<item name="android:windowEnterAnimation">@anim/step_next_in</item>
+		<item name="android:windowExitAnimation">@anim/step_next_out</item>
+	</style>
+
 	<!-- Use this with care. Only used for the screen filter warning dialog -->
 	<style name="BriarDialogThemeNoFilter" parent="BriarDialogTheme">
 		<item name="android:filterTouchesWhenObscured">false</item>

briar-api/src/main/java/org/briarproject/briar/api/autodelete/AutoDeleteConstants.java

@@ -0,0 +1,23 @@
+package org.briarproject.briar.api.autodelete;
+
+import static java.util.concurrent.TimeUnit.DAYS;
+import static java.util.concurrent.TimeUnit.MINUTES;
+
+public interface AutoDeleteConstants {
+
+	/**
+	 * The minimum valid auto-delete timer duration in milliseconds.
+	 */
+	long MIN_AUTO_DELETE_TIMER_MS = MINUTES.toMillis(1);
+
+	/**
+	 * The maximum valid auto-delete timer duration in milliseconds.
+	 */
+	long MAX_AUTO_DELETE_TIMER_MS = DAYS.toMillis(365);
+
+	/**
+	 * Placeholder value indicating that a message has no auto-delete timer.
+	 * This value should not be sent over the wire - send null instead.
+	 */
+	long NO_AUTO_DELETE_TIMER = -1;
+}

briar-api/src/main/java/org/briarproject/briar/api/autodelete/AutoDeleteManager.java

@@ -0,0 +1,56 @@
+package org.briarproject.briar.api.autodelete;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.ClientId;
+
+@NotNullByDefault
+public interface AutoDeleteManager {
+
+	/**
+	 * The unique ID of the auto-delete client.
+	 */
+	ClientId CLIENT_ID = new ClientId("org.briarproject.briar.autodelete");
+
+	/**
+	 * The current major version of the auto-delete client.
+	 */
+	int MAJOR_VERSION = 0;
+
+	/**
+	 * The current minor version of the auto-delete client.
+	 */
+	int MINOR_VERSION = 0;
+
+	/**
+	 * Returns the auto-delete timer duration for the given contact. Use
+	 * {@link #getAutoDeleteTimer(Transaction, ContactId, long)} if the timer
+	 * will be used in an outgoing message.
+	 */
+	long getAutoDeleteTimer(Transaction txn, ContactId c) throws DbException;
+
+	/**
+	 * Returns the auto-delete timer duration for the given contact, for use in
+	 * a message with the given timestamp. The timestamp is stored.
+	 */
+	long getAutoDeleteTimer(Transaction txn, ContactId c, long timestamp)
+			throws DbException;
+
+	/**
+	 * Sets the auto-delete timer duration for the given contact.
+	 */
+	void setAutoDeleteTimer(Transaction txn, ContactId c, long timer)
+			throws DbException;
+
+	/**
+	 * Receives an auto-delete timer duration from the given contact, carried
+	 * in a message with the given timestamp. The local timer is set to the
+	 * same duration unless it has been
+	 * {@link #setAutoDeleteTimer(Transaction, ContactId, long) changed} more
+	 * recently than the remote timer.
+	 */
+	void receiveAutoDeleteTimer(Transaction txn, ContactId c, long timer,
+			long timestamp) throws DbException;
+}

briar-api/src/main/java/org/briarproject/briar/api/autodelete/UnexpectedTimerException.java

@@ -0,0 +1,12 @@
+package org.briarproject.briar.api.autodelete;
+
+import org.briarproject.bramble.api.db.DbException;
+
+/**
+ * Thrown when a database operation is attempted as part of message storing
+ * and the operation is expecting a different timer state. This
+ * exception may occur due to concurrent updates and does not indicate a
+ * database error.
+ */
+public class UnexpectedTimerException extends DbException {
+}

briar-api/src/main/java/org/briarproject/briar/api/autodelete/event/AutoDeleteTimerMirroredEvent.java

@@ -0,0 +1,28 @@
+package org.briarproject.briar.api.autodelete.event;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+public class AutoDeleteTimerMirroredEvent extends Event {
+
+	private final ContactId contactId;
+	private final long newTimer;
+
+	public AutoDeleteTimerMirroredEvent(ContactId contactId, long newTimer) {
+		this.contactId = contactId;
+		this.newTimer = newTimer;
+	}
+
+	public ContactId getContactId() {
+		return contactId;
+	}
+
+	public long getNewTimer() {
+		return newTimer;
+	}
+}

briar-api/src/main/java/org/briarproject/briar/api/blog/BlogInvitationRequest.java

@@ -15,9 +15,9 @@ public class BlogInvitationRequest extends InvitationRequest<Blog> {
 	public BlogInvitationRequest(MessageId id, GroupId groupId, long time,
 			boolean local, boolean read, boolean sent, boolean seen,
 			SessionId sessionId, Blog blog, @Nullable String text,
-			boolean available, boolean canBeOpened) {
+			boolean available, boolean canBeOpened, long autoDeleteTimer) {
 		super(id, groupId, time, local, read, sent, seen, sessionId, blog,
-				text, available, canBeOpened);
+				text, available, canBeOpened, autoDeleteTimer);
 	}
 
 	@Override

briar-api/src/main/java/org/briarproject/briar/api/blog/BlogInvitationResponse.java

@@ -12,9 +12,10 @@ public class BlogInvitationResponse extends InvitationResponse {
 
 	public BlogInvitationResponse(MessageId id, GroupId groupId, long time,
 			boolean local, boolean read, boolean sent, boolean seen,
-			SessionId sessionId, boolean accept, GroupId shareableId) {
+			SessionId sessionId, boolean accept, GroupId shareableId,
+			long autoDeleteTimer) {
 		super(id, groupId, time, local, read, sent, seen, sessionId,
-				accept, shareableId);
+				accept, shareableId, autoDeleteTimer);
 	}
 
 	@Override

briar-api/src/main/java/org/briarproject/briar/api/blog/BlogSharingManager.java

@@ -18,5 +18,5 @@ public interface BlogSharingManager extends SharingManager<Blog> {
 	/**
 	 * The current minor version of the blog sharing client.
 	 */
-	int MINOR_VERSION = 0;
+	int MINOR_VERSION = 1;
 }

briar-api/src/main/java/org/briarproject/briar/api/conversation/ConversationManager.java

@@ -48,6 +48,13 @@ public interface ConversationManager {
 	 */
 	GroupCount getGroupCount(Transaction txn, ContactId c) throws DbException;
 
+	/**
+	 * Returns a timestamp for an outgoing message, which is later than the
+	 * timestamp of any message in the conversation with the given contact.
+	 */
+	long getTimestampForOutgoingMessage(Transaction txn, ContactId c)
+			throws DbException;
+
 	/**
 	 * Deletes all messages exchanged with the given contact.
 	 */

briar-api/src/main/java/org/briarproject/briar/api/conversation/ConversationMessageHeader.java

@@ -12,18 +12,20 @@ public abstract class ConversationMessageHeader {
 
 	private final MessageId id;
 	private final GroupId groupId;
-	private final long timestamp;
-	private final boolean local, sent, seen, read;
+	private final long timestamp, autoDeleteTimer;
+	private final boolean local, read, sent, seen;
 
-	public ConversationMessageHeader(MessageId id, GroupId groupId, long timestamp,
-			boolean local, boolean read, boolean sent, boolean seen) {
+	public ConversationMessageHeader(MessageId id, GroupId groupId,
+			long timestamp, boolean local, boolean read, boolean sent,
+			boolean seen, long autoDeleteTimer) {
 		this.id = id;
 		this.groupId = groupId;
 		this.timestamp = timestamp;
 		this.local = local;
+		this.read = read;
 		this.sent = sent;
 		this.seen = seen;
-		this.read = read;
+		this.autoDeleteTimer = autoDeleteTimer;
 	}
 
 	public MessageId getId() {
@@ -55,4 +57,8 @@ public abstract class ConversationMessageHeader {
 	}
 
 	public abstract <T> T accept(ConversationMessageVisitor<T> v);
+
+	public long getAutoDeleteTimer() {
+		return autoDeleteTimer;
+	}
 }

briar-api/src/main/java/org/briarproject/briar/api/conversation/ConversationRequest.java

@@ -20,11 +20,12 @@ public abstract class ConversationRequest<N extends Nameable>
 	private final String text;
 	private final boolean answered;
 
-	public ConversationRequest(MessageId messageId, GroupId groupId, long time,
-			boolean local, boolean read, boolean sent, boolean seen,
-			SessionId sessionId, N nameable, @Nullable String text,
-			boolean answered) {
-		super(messageId, groupId, time, local, read, sent, seen);
+	public ConversationRequest(MessageId messageId, GroupId groupId,
+			long timestamp, boolean local, boolean read, boolean sent,
+			boolean seen, SessionId sessionId, N nameable,
+			@Nullable String text, boolean answered, long autoDeleteTimer) {
+		super(messageId, groupId, timestamp, local, read, sent, seen,
+				autoDeleteTimer);
 		this.sessionId = sessionId;
 		this.nameable = nameable;
 		this.text = text;

briar-api/src/main/java/org/briarproject/briar/api/conversation/ConversationResponse.java

@@ -16,8 +16,8 @@ public abstract class ConversationResponse extends ConversationMessageHeader {
 
 	public ConversationResponse(MessageId id, GroupId groupId, long time,
 			boolean local, boolean read, boolean sent, boolean seen,
-			SessionId sessionId, boolean accepted) {
-		super(id, groupId, time, local, read, sent, seen);
+			SessionId sessionId, boolean accepted, long autoDeleteTimer) {
+		super(id, groupId, time, local, read, sent, seen, autoDeleteTimer);
 		this.sessionId = sessionId;
 		this.accepted = accepted;
 	}

briar-api/src/main/java/org/briarproject/briar/api/forum/ForumInvitationRequest.java

@@ -17,9 +17,9 @@ public class ForumInvitationRequest extends InvitationRequest<Forum> {
 	public ForumInvitationRequest(MessageId id, GroupId groupId, long time,
 			boolean local, boolean read, boolean sent, boolean seen,
 			SessionId sessionId, Forum forum, @Nullable String text,
-			boolean available, boolean canBeOpened) {
+			boolean available, boolean canBeOpened, long autoDeleteTimer) {
 		super(id, groupId, time, local, read, sent, seen, sessionId, forum,
-				text, available, canBeOpened);
+				text, available, canBeOpened, autoDeleteTimer);
 	}
 
 	@Override

briar-api/src/main/java/org/briarproject/briar/api/forum/ForumInvitationResponse.java

@@ -15,9 +15,10 @@ public class ForumInvitationResponse extends InvitationResponse {
 
 	public ForumInvitationResponse(MessageId id, GroupId groupId, long time,
 			boolean local, boolean read, boolean sent, boolean seen,
-			SessionId sessionId, boolean accept, GroupId shareableId) {
+			SessionId sessionId, boolean accept, GroupId shareableId,
+			long autoDeleteTimer) {
 		super(id, groupId, time, local, read, sent, seen, sessionId,
-				accept, shareableId);
+				accept, shareableId, autoDeleteTimer);
 	}
 
 	@Override

briar-api/src/main/java/org/briarproject/briar/api/forum/ForumSharingManager.java

@@ -18,5 +18,5 @@ public interface ForumSharingManager extends SharingManager<Forum> {
 	/**
 	 * The current minor version of the forum sharing client.
 	 */
-	int MINOR_VERSION = 0;
+	int MINOR_VERSION = 1;
 }

briar-api/src/main/java/org/briarproject/briar/api/introduction/IntroductionManager.java

@@ -31,18 +31,18 @@ public interface IntroductionManager extends ConversationClient {
 	/**
 	 * The current minor version of the introduction client.
 	 */
-	int MINOR_VERSION = 0;
+	int MINOR_VERSION = 1;
 
 	/**
 	 * Sends two initial introduction messages.
 	 */
-	void makeIntroduction(Contact c1, Contact c2, @Nullable String text,
-			long timestamp) throws DbException;
+	void makeIntroduction(Contact c1, Contact c2, @Nullable String text)
+			throws DbException;
 
 	/**
 	 * Responds to an introduction.
 	 */
 	void respondToIntroduction(ContactId contactId, SessionId sessionId,
-			long timestamp, boolean accept) throws DbException;
+			boolean accept) throws DbException;
 
 }

briar-api/src/main/java/org/briarproject/briar/api/introduction/IntroductionRequest.java

@@ -18,12 +18,12 @@ public class IntroductionRequest extends ConversationRequest<Author> {
 
 	private final AuthorInfo authorInfo;
 
-	public IntroductionRequest(MessageId messageId, GroupId groupId,
-			long time, boolean local, boolean read, boolean sent, boolean seen,
+	public IntroductionRequest(MessageId messageId, GroupId groupId, long time,
+			boolean local, boolean read, boolean sent, boolean seen,
 			SessionId sessionId, Author author, @Nullable String text,
-			boolean answered, AuthorInfo authorInfo) {
+			boolean answered, AuthorInfo authorInfo, long autoDeleteTimer) {
 		super(messageId, groupId, time, local, read, sent, seen, sessionId,
-				author, text, answered);
+				author, text, answered, autoDeleteTimer);
 		this.authorInfo = authorInfo;
 	}
 

briar-api/src/main/java/org/briarproject/briar/api/introduction/IntroductionResponse.java

@@ -25,9 +25,10 @@ public class IntroductionResponse extends ConversationResponse {
 	public IntroductionResponse(MessageId messageId, GroupId groupId, long time,
 			boolean local, boolean read, boolean sent, boolean seen,
 			SessionId sessionId, boolean accepted, Author author,
-			AuthorInfo introducedAuthorInfo, Role role, boolean canSucceed) {
+			AuthorInfo introducedAuthorInfo, Role role, boolean canSucceed,
+			long autoDeleteTimer) {
 		super(messageId, groupId, time, local, read, sent, seen, sessionId,
-				accepted);
+				accepted, autoDeleteTimer);
 		this.introducedAuthor = author;
 		this.introducedAuthorInfo = introducedAuthorInfo;
 		this.ourRole = role;

briar-api/src/main/java/org/briarproject/briar/api/messaging/MessagingManager.java

@@ -32,13 +32,18 @@ public interface MessagingManager extends ConversationClient {
 	/**
 	 * The current minor version of the messaging client.
 	 */
-	int MINOR_VERSION = 2;
+	int MINOR_VERSION = 3;
 
 	/**
 	 * Stores a local private message.
 	 */
 	void addLocalMessage(PrivateMessage m) throws DbException;
 
+	/**
+	 * Stores a local private message.
+	 */
+	void addLocalMessage(Transaction txn, PrivateMessage m) throws DbException;
+
 	/**
 	 * Stores a local attachment message.
 	 *
@@ -70,12 +75,8 @@ public interface MessagingManager extends ConversationClient {
 	String getMessageText(MessageId m) throws DbException;
 
 	/**
-	 * Returns true if the contact with the given {@link ContactId} does support
-	 * image attachments.
-	 * <p>
-	 * Added: 2019-01-01
+	 * Returns the private message format supported by the given contact.
 	 */
-	boolean contactSupportsImages(Transaction txn, ContactId c)
+	PrivateMessageFormat getContactMessageFormat(Transaction txn, ContactId c)
 			throws DbException;
-
 }

briar-api/src/main/java/org/briarproject/briar/api/messaging/PrivateMessage.java

@@ -9,44 +9,66 @@ import java.util.List;
 import javax.annotation.concurrent.Immutable;
 
 import static java.util.Collections.emptyList;
+import static org.briarproject.briar.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
+import static org.briarproject.briar.api.messaging.PrivateMessageFormat.TEXT_IMAGES;
+import static org.briarproject.briar.api.messaging.PrivateMessageFormat.TEXT_IMAGES_AUTO_DELETE;
+import static org.briarproject.briar.api.messaging.PrivateMessageFormat.TEXT_ONLY;
 
 @Immutable
 @NotNullByDefault
 public class PrivateMessage {
 
 	private final Message message;
-	private final boolean legacyFormat, hasText;
+	private final boolean hasText;
 	private final List<AttachmentHeader> attachmentHeaders;
+	private final long autoDeleteTimer;
+	private final PrivateMessageFormat format;
 
 	/**
-	 * Constructor for private messages in the legacy format, which does not
-	 * support attachments.
+	 * Constructor for private messages in the
+	 * {@link PrivateMessageFormat#TEXT_ONLY TEXT_ONLY} format.
 	 */
 	public PrivateMessage(Message message) {
 		this.message = message;
-		legacyFormat = true;
 		hasText = true;
 		attachmentHeaders = emptyList();
+		autoDeleteTimer = NO_AUTO_DELETE_TIMER;
+		format = TEXT_ONLY;
 	}
 
 	/**
-	 * Constructor for private messages in the current format, which supports
-	 * attachments.
+	 * Constructor for private messages in the
+	 * {@link PrivateMessageFormat#TEXT_IMAGES TEXT_IMAGES} format.
 	 */
 	public PrivateMessage(Message message, boolean hasText,
 			List<AttachmentHeader> headers) {
 		this.message = message;
 		this.hasText = hasText;
 		this.attachmentHeaders = headers;
-		legacyFormat = false;
+		autoDeleteTimer = NO_AUTO_DELETE_TIMER;
+		format = TEXT_IMAGES;
+	}
+
+	/**
+	 * Constructor for private messages in the
+	 * {@link PrivateMessageFormat#TEXT_IMAGES_AUTO_DELETE TEXT_IMAGES_AUTO_DELETE}
+	 * format.
+	 */
+	public PrivateMessage(Message message, boolean hasText,
+			List<AttachmentHeader> headers, long autoDeleteTimer) {
+		this.message = message;
+		this.hasText = hasText;
+		this.attachmentHeaders = headers;
+		this.autoDeleteTimer = autoDeleteTimer;
+		format = TEXT_IMAGES_AUTO_DELETE;
 	}
 
 	public Message getMessage() {
 		return message;
 	}
 
-	public boolean isLegacyFormat() {
-		return legacyFormat;
+	public PrivateMessageFormat getFormat() {
+		return format;
 	}
 
 	public boolean hasText() {
@@ -56,4 +78,8 @@ public class PrivateMessage {
 	public List<AttachmentHeader> getAttachmentHeaders() {
 		return attachmentHeaders;
 	}
+
+	public long getAutoDeleteTimer() {
+		return autoDeleteTimer;
+	}
 }

briar-api/src/main/java/org/briarproject/briar/api/messaging/PrivateMessageFactory.java

@@ -12,11 +12,29 @@ import javax.annotation.Nullable;
 @NotNullByDefault
 public interface PrivateMessageFactory {
 
+	/**
+	 * Creates a private message in the
+	 * {@link PrivateMessageFormat#TEXT_ONLY TEXT_ONLY} format.
+	 */
 	PrivateMessage createLegacyPrivateMessage(GroupId groupId, long timestamp,
 			String text) throws FormatException;
 
+	/**
+	 * Creates a private message in the
+	 * {@link PrivateMessageFormat#TEXT_IMAGES TEXT_IMAGES} format. This format
+	 * requires the contact to support client version 0.1 or higher.
+	 */
 	PrivateMessage createPrivateMessage(GroupId groupId, long timestamp,
 			@Nullable String text, List<AttachmentHeader> headers)
 			throws FormatException;
 
+	/**
+	 * Creates a private message in the
+	 * {@link PrivateMessageFormat#TEXT_IMAGES_AUTO_DELETE TEXT_IMAGES_AUTO_DELETE}
+	 * format. This format requires the contact to support client version 0.3
+	 * or higher.
+	 */
+	PrivateMessage createPrivateMessage(GroupId groupId, long timestamp,
+			@Nullable String text, List<AttachmentHeader> headers,
+			long autoDeleteTimer) throws FormatException;
 }

briar-api/src/main/java/org/briarproject/briar/api/messaging/PrivateMessageFormat.java

@@ -0,0 +1,24 @@
+package org.briarproject.briar.api.messaging;
+
+public enum PrivateMessageFormat {
+
+	/**
+	 * First version of the private message format, which doesn't support
+	 * image attachments or auto-deletion.
+	 */
+	TEXT_ONLY,
+
+	/**
+	 * Second version of the private message format, which supports image
+	 * attachments but not auto-deletion. Support for this format was
+	 * added in client version 0.1.
+	 */
+	TEXT_IMAGES,
+
+	/**
+	 * Third version of the private message format, which supports image
+	 * attachments and auto-deletion. Support for this format was added
+	 * in client version 0.3.
+	 */
+	TEXT_IMAGES_AUTO_DELETE
+}

briar-api/src/main/java/org/briarproject/briar/api/messaging/PrivateMessageHeader.java

@@ -20,8 +20,9 @@ public class PrivateMessageHeader extends ConversationMessageHeader {
 
 	public PrivateMessageHeader(MessageId id, GroupId groupId, long timestamp,
 			boolean local, boolean read, boolean sent, boolean seen,
-			boolean hasText, List<AttachmentHeader> headers) {
-		super(id, groupId, timestamp, local, read, sent, seen);
+			boolean hasText, List<AttachmentHeader> headers,
+			long autoDeleteTimer) {
+		super(id, groupId, timestamp, local, read, sent, seen, autoDeleteTimer);
 		this.hasText = hasText;
 		this.attachmentHeaders = headers;
 	}
@@ -38,5 +39,4 @@ public class PrivateMessageHeader extends ConversationMessageHeader {
 	public <T> T accept(ConversationMessageVisitor<T> v) {
 		return v.visitPrivateMessageHeader(this);
 	}
-
 }

briar-api/src/main/java/org/briarproject/briar/api/privategroup/invitation/GroupInvitationManager.java

@@ -32,7 +32,7 @@ public interface GroupInvitationManager extends ConversationClient {
 	/**
 	 * The current minor version of the private group invitation client.
 	 */
-	int MINOR_VERSION = 0;
+	int MINOR_VERSION = 1;
 
 	/**
 	 * Sends an invitation to share the given private group with the given
@@ -43,7 +43,8 @@ public interface GroupInvitationManager extends ConversationClient {
 	 * pending.
 	 */
 	void sendInvitation(GroupId g, ContactId c, @Nullable String text,
-			long timestamp, byte[] signature) throws DbException;
+			long timestamp, byte[] signature, long autoDeleteTimer)
+			throws DbException;
 
 	/**
 	 * Responds to a pending private group invitation from the given contact.

briar-api/src/main/java/org/briarproject/briar/api/privategroup/invitation/GroupInvitationRequest.java

@@ -18,9 +18,10 @@ public class GroupInvitationRequest extends InvitationRequest<PrivateGroup> {
 	public GroupInvitationRequest(MessageId id, GroupId groupId, long time,
 			boolean local, boolean read, boolean sent, boolean seen,
 			SessionId sessionId, PrivateGroup shareable,
-			@Nullable String text, boolean available, boolean canBeOpened) {
+			@Nullable String text, boolean available, boolean canBeOpened,
+			long autoDeleteTimer) {
 		super(id, groupId, time, local, read, sent, seen, sessionId, shareable,
-				text, available, canBeOpened);
+				text, available, canBeOpened, autoDeleteTimer);
 	}
 
 	@Override

briar-api/src/main/java/org/briarproject/briar/api/privategroup/invitation/GroupInvitationResponse.java

@@ -15,9 +15,10 @@ public class GroupInvitationResponse extends InvitationResponse {
 
 	public GroupInvitationResponse(MessageId id, GroupId groupId, long time,
 			boolean local, boolean read, boolean sent, boolean seen,
-			SessionId sessionId, boolean accept, GroupId shareableId) {
+			SessionId sessionId, boolean accept, GroupId shareableId,
+			long autoDeleteTimer) {
 		super(id, groupId, time, local, read, sent, seen, sessionId,
-				accept, shareableId);
+				accept, shareableId, autoDeleteTimer);
 	}
 
 	@Override

briar-api/src/main/java/org/briarproject/briar/api/sharing/InvitationRequest.java

@@ -15,9 +15,9 @@ public abstract class InvitationRequest<S extends Shareable> extends
 	public InvitationRequest(MessageId messageId, GroupId groupId, long time,
 			boolean local, boolean read, boolean sent, boolean seen,
 			SessionId sessionId, S object, @Nullable String text,
-			boolean available, boolean canBeOpened) {
+			boolean available, boolean canBeOpened, long autoDeleteTimer) {
 		super(messageId, groupId, time, local, read, sent, seen, sessionId,
-				object, text, !available);
+				object, text, !available, autoDeleteTimer);
 		this.canBeOpened = canBeOpened;
 	}
 

briar-api/src/main/java/org/briarproject/briar/api/sharing/InvitationResponse.java

@@ -11,8 +11,10 @@ public abstract class InvitationResponse extends ConversationResponse {
 
 	public InvitationResponse(MessageId id, GroupId groupId, long time,
 			boolean local, boolean read, boolean sent, boolean seen,
-			SessionId sessionId, boolean accepted, GroupId shareableId) {
-		super(id, groupId, time, local, read, sent, seen, sessionId, accepted);
+			SessionId sessionId, boolean accepted, GroupId shareableId,
+			long autoDeleteTimer) {
+		super(id, groupId, time, local, read, sent, seen, sessionId, accepted,
+				autoDeleteTimer);
 		this.shareableId = shareableId;
 	}
 

briar-api/src/main/java/org/briarproject/briar/api/sharing/SharingManager.java

@@ -22,7 +22,7 @@ public interface SharingManager<S extends Shareable>
 	 * including optional text.
 	 */
 	void sendInvitation(GroupId shareableId, ContactId contactId,
-			@Nullable String text, long timestamp) throws DbException;
+			@Nullable String text) throws DbException;
 
 	/**
 	 * Responds to a pending group invitation

briar-core/src/main/java/org/briarproject/briar/BriarCoreEagerSingletons.java

@@ -1,5 +1,6 @@
 package org.briarproject.briar;
 
+import org.briarproject.briar.autodelete.AutoDeleteModule;
 import org.briarproject.briar.avatar.AvatarModule;
 import org.briarproject.briar.blog.BlogModule;
 import org.briarproject.briar.feed.FeedModule;
@@ -13,6 +14,8 @@ import org.briarproject.briar.sharing.SharingModule;
 
 public interface BriarCoreEagerSingletons {
 
+	void inject(AutoDeleteModule.EagerSingletons init);
+
 	void inject(AvatarModule.EagerSingletons init);
 
 	void inject(BlogModule.EagerSingletons init);
@@ -36,6 +39,7 @@ public interface BriarCoreEagerSingletons {
 	class Helper {
 
 		public static void injectEagerSingletons(BriarCoreEagerSingletons c) {
+			c.inject(new AutoDeleteModule.EagerSingletons());
 			c.inject(new AvatarModule.EagerSingletons());
 			c.inject(new BlogModule.EagerSingletons());
 			c.inject(new FeedModule.EagerSingletons());

briar-core/src/main/java/org/briarproject/briar/BriarCoreModule.java

@@ -1,6 +1,7 @@
 package org.briarproject.briar;
 
 import org.briarproject.briar.attachment.AttachmentModule;
+import org.briarproject.briar.autodelete.AutoDeleteModule;
 import org.briarproject.briar.avatar.AvatarModule;
 import org.briarproject.briar.blog.BlogModule;
 import org.briarproject.briar.client.BriarClientModule;
@@ -18,6 +19,8 @@ import org.briarproject.briar.test.TestModule;
 import dagger.Module;
 
 @Module(includes = {
+		AttachmentModule.class,
+		AutoDeleteModule.class,
 		AvatarModule.class,
 		BlogModule.class,
 		BriarClientModule.class,
@@ -27,7 +30,6 @@ import dagger.Module;
 		GroupInvitationModule.class,
 		IdentityModule.class,
 		IntroductionModule.class,
-		AttachmentModule.class,
 		MessagingModule.class,
 		PrivateGroupModule.class,
 		SharingModule.class,

briar-core/src/main/java/org/briarproject/briar/autodelete/AutoDeleteConstants.java

@@ -0,0 +1,29 @@
+package org.briarproject.briar.autodelete;
+
+interface AutoDeleteConstants {
+
+	/**
+	 * Group metadata key for storing the auto-delete timer duration.
+	 */
+	String GROUP_KEY_TIMER = "autoDeleteTimer";
+
+	/**
+	 * Group metadata key for storing the timestamp of the latest incoming or
+	 * outgoing message carrying an auto-delete timer (including a null timer).
+	 */
+	String GROUP_KEY_TIMESTAMP = "autoDeleteTimestamp";
+
+	/**
+	 * Group metadata key for storing the previous auto-delete timer duration.
+	 * This is used to decide whether a local change to the duration should be
+	 * overwritten by a duration received from the contact.
+	 */
+	String GROUP_KEY_PREVIOUS_TIMER = "autoDeletePreviousTimer";
+
+	/**
+	 * Special value for {@link #GROUP_KEY_PREVIOUS_TIMER} indicating that
+	 * there are no local changes to the auto-delete timer duration that need
+	 * to be compared with durations received from the contact.
+	 */
+	long NO_PREVIOUS_TIMER = 0;
+}

briar-core/src/main/java/org/briarproject/briar/autodelete/AutoDeleteManagerImpl.java

@@ -0,0 +1,191 @@
+package org.briarproject.briar.autodelete;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.client.ClientHelper;
+import org.briarproject.bramble.api.client.ContactGroupFactory;
+import org.briarproject.bramble.api.contact.Contact;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.ContactManager.ContactHook;
+import org.briarproject.bramble.api.data.BdfDictionary;
+import org.briarproject.bramble.api.data.BdfEntry;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager.OpenDatabaseHook;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.Group;
+import org.briarproject.bramble.api.sync.GroupFactory;
+import org.briarproject.briar.api.autodelete.AutoDeleteManager;
+import org.briarproject.briar.api.autodelete.event.AutoDeleteTimerMirroredEvent;
+
+import java.util.logging.Logger;
+
+import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
+
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.briar.api.autodelete.AutoDeleteConstants.MAX_AUTO_DELETE_TIMER_MS;
+import static org.briarproject.briar.api.autodelete.AutoDeleteConstants.MIN_AUTO_DELETE_TIMER_MS;
+import static org.briarproject.briar.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
+import static org.briarproject.briar.autodelete.AutoDeleteConstants.GROUP_KEY_PREVIOUS_TIMER;
+import static org.briarproject.briar.autodelete.AutoDeleteConstants.GROUP_KEY_TIMER;
+import static org.briarproject.briar.autodelete.AutoDeleteConstants.GROUP_KEY_TIMESTAMP;
+import static org.briarproject.briar.autodelete.AutoDeleteConstants.NO_PREVIOUS_TIMER;
+
+@Immutable
+@NotNullByDefault
+class AutoDeleteManagerImpl
+		implements AutoDeleteManager, OpenDatabaseHook, ContactHook {
+
+	private static final Logger LOG =
+			getLogger(AutoDeleteManagerImpl.class.getName());
+
+	private final DatabaseComponent db;
+	private final ClientHelper clientHelper;
+	private final GroupFactory groupFactory;
+	private final Group localGroup;
+
+	@Inject
+	AutoDeleteManagerImpl(
+			DatabaseComponent db,
+			ClientHelper clientHelper,
+			GroupFactory groupFactory,
+			ContactGroupFactory contactGroupFactory) {
+		this.db = db;
+		this.clientHelper = clientHelper;
+		this.groupFactory = groupFactory;
+		localGroup = contactGroupFactory.createLocalGroup(CLIENT_ID,
+				MAJOR_VERSION);
+	}
+
+	@Override
+	public void onDatabaseOpened(Transaction txn) throws DbException {
+		if (db.containsGroup(txn, localGroup.getId())) return;
+		db.addGroup(txn, localGroup);
+		// Set things up for any pre-existing contacts
+		for (Contact c : db.getContacts(txn)) addingContact(txn, c);
+	}
+
+	@Override
+	public void addingContact(Transaction txn, Contact c) throws DbException {
+		Group g = getGroup(c);
+		db.addGroup(txn, g);
+		clientHelper.setContactId(txn, g.getId(), c.getId());
+	}
+
+	@Override
+	public void removingContact(Transaction txn, Contact c) throws DbException {
+		db.removeGroup(txn, getGroup(c));
+	}
+
+	@Override
+	public long getAutoDeleteTimer(Transaction txn, ContactId c)
+			throws DbException {
+		try {
+			Group g = getGroup(db.getContact(txn, c));
+			BdfDictionary meta =
+					clientHelper.getGroupMetadataAsDictionary(txn, g.getId());
+			return meta.getLong(GROUP_KEY_TIMER, NO_AUTO_DELETE_TIMER);
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
+	@Override
+	public long getAutoDeleteTimer(Transaction txn, ContactId c, long timestamp)
+			throws DbException {
+		try {
+			Group g = getGroup(db.getContact(txn, c));
+			BdfDictionary meta =
+					clientHelper.getGroupMetadataAsDictionary(txn, g.getId());
+			long timer = meta.getLong(GROUP_KEY_TIMER, NO_AUTO_DELETE_TIMER);
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Sending message with auto-delete timer " + timer);
+			}
+			// Update the timestamp and clear the previous timer, if any
+			meta = BdfDictionary.of(
+					new BdfEntry(GROUP_KEY_TIMESTAMP, timestamp),
+					new BdfEntry(GROUP_KEY_PREVIOUS_TIMER, NO_PREVIOUS_TIMER));
+			clientHelper.mergeGroupMetadata(txn, g.getId(), meta);
+			return timer;
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
+	@Override
+	public void setAutoDeleteTimer(Transaction txn, ContactId c, long timer)
+			throws DbException {
+		validateTimer(timer);
+		try {
+			Group g = getGroup(db.getContact(txn, c));
+			BdfDictionary meta =
+					clientHelper.getGroupMetadataAsDictionary(txn, g.getId());
+			long oldTimer = meta.getLong(GROUP_KEY_TIMER, NO_AUTO_DELETE_TIMER);
+			if (timer == oldTimer) return;
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Setting auto-delete timer to " + timer);
+			}
+			// Store the new timer and the previous timer
+			meta = BdfDictionary.of(
+					new BdfEntry(GROUP_KEY_TIMER, timer),
+					new BdfEntry(GROUP_KEY_PREVIOUS_TIMER, oldTimer));
+			clientHelper.mergeGroupMetadata(txn, g.getId(), meta);
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
+	@Override
+	public void receiveAutoDeleteTimer(Transaction txn, ContactId c,
+			long timer, long timestamp) throws DbException {
+		validateTimer(timer);
+		try {
+			Group g = getGroup(db.getContact(txn, c));
+			BdfDictionary meta =
+					clientHelper.getGroupMetadataAsDictionary(txn, g.getId());
+			long oldTimestamp = meta.getLong(GROUP_KEY_TIMESTAMP, 0L);
+			if (timestamp <= oldTimestamp) return;
+			long oldTimer =
+					meta.getLong(GROUP_KEY_PREVIOUS_TIMER, NO_PREVIOUS_TIMER);
+			meta = new BdfDictionary();
+			if (oldTimer == NO_PREVIOUS_TIMER) {
+				// We don't have an unsent change. Mirror their timer
+				if (LOG.isLoggable(INFO)) {
+					LOG.info("Mirroring auto-delete timer " + timer);
+				}
+				meta.put(GROUP_KEY_TIMER, timer);
+				txn.attach(new AutoDeleteTimerMirroredEvent(c, timer));
+			} else if (timer != oldTimer) {
+				// Their sent change trumps our unsent change. Mirror their
+				// timer and clear the previous timer to drop our unsent change
+				if (LOG.isLoggable(INFO)) {
+					LOG.info("Mirroring auto-delete timer " + timer
+							+ " and forgetting unsent change");
+				}
+				meta.put(GROUP_KEY_TIMER, timer);
+				meta.put(GROUP_KEY_PREVIOUS_TIMER, NO_PREVIOUS_TIMER);
+				txn.attach(new AutoDeleteTimerMirroredEvent(c, timer));
+			}
+			// Always update the timestamp
+			meta.put(GROUP_KEY_TIMESTAMP, timestamp);
+			clientHelper.mergeGroupMetadata(txn, g.getId(), meta);
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
+	private Group getGroup(Contact c) {
+		byte[] descriptor = c.getAuthor().getId().getBytes();
+		return groupFactory.createGroup(CLIENT_ID, MAJOR_VERSION, descriptor);
+	}
+
+	private void validateTimer(long timer) {
+		if (timer != NO_AUTO_DELETE_TIMER &&
+				(timer < MIN_AUTO_DELETE_TIMER_MS ||
+						timer > MAX_AUTO_DELETE_TIMER_MS)) {
+			throw new IllegalArgumentException();
+		}
+	}
+}

briar-core/src/main/java/org/briarproject/briar/autodelete/AutoDeleteModule.java

@@ -0,0 +1,32 @@
+package org.briarproject.briar.autodelete;
+
+import org.briarproject.bramble.api.contact.ContactManager;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.briar.api.autodelete.AutoDeleteManager;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class AutoDeleteModule {
+
+	public static class EagerSingletons {
+		@Inject
+		AutoDeleteManager autoDeleteManager;
+	}
+
+	@Provides
+	@Singleton
+	AutoDeleteManager provideAutoDeleteManager(
+			LifecycleManager lifecycleManager, ContactManager contactManager,
+			AutoDeleteManagerImpl autoDeleteManager) {
+		lifecycleManager.registerOpenDatabaseHook(autoDeleteManager);
+		contactManager.registerContactHook(autoDeleteManager);
+		// Don't need to register with the client versioning manager as this
+		// client's groups aren't shared with contacts
+		return autoDeleteManager;
+	}
+}

briar-core/src/main/java/org/briarproject/briar/introduction/AbortMessage.java

@@ -8,6 +8,8 @@ import org.briarproject.briar.api.client.SessionId;
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 
+import static org.briarproject.briar.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
+
 @Immutable
 @NotNullByDefault
 class AbortMessage extends AbstractIntroductionMessage {
@@ -16,7 +18,8 @@ class AbortMessage extends AbstractIntroductionMessage {
 
 	protected AbortMessage(MessageId messageId, GroupId groupId, long timestamp,
 			@Nullable MessageId previousMessageId, SessionId sessionId) {
-		super(messageId, groupId, timestamp, previousMessageId);
+		super(messageId, groupId, timestamp, previousMessageId,
+				NO_AUTO_DELETE_TIMER);
 		this.sessionId = sessionId;
 	}
 

briar-core/src/main/java/org/briarproject/briar/introduction/AbstractIntroductionMessage.java

@@ -16,13 +16,16 @@ abstract class AbstractIntroductionMessage {
 	private final long timestamp;
 	@Nullable
 	private final MessageId previousMessageId;
+	private final long autoDeleteTimer;
 
 	AbstractIntroductionMessage(MessageId messageId, GroupId groupId,
-			long timestamp, @Nullable MessageId previousMessageId) {
+			long timestamp, @Nullable MessageId previousMessageId,
+			long autoDeleteTimer) {
 		this.messageId = messageId;
 		this.groupId = groupId;
 		this.timestamp = timestamp;
 		this.previousMessageId = previousMessageId;
+		this.autoDeleteTimer = autoDeleteTimer;
 	}
 
 	MessageId getMessageId() {
@@ -42,4 +45,7 @@ abstract class AbstractIntroductionMessage {
 		return previousMessageId;
 	}
 
+	public long getAutoDeleteTimer() {
+		return autoDeleteTimer;
+	}
 }

briar-core/src/main/java/org/briarproject/briar/introduction/AbstractProtocolEngine.java

@@ -4,6 +4,7 @@ import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.api.client.ClientHelper;
 import org.briarproject.bramble.api.client.ContactGroupFactory;
 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.PublicKey;
 import org.briarproject.bramble.api.data.BdfDictionary;
@@ -16,11 +17,15 @@ import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.versioning.ClientVersioningManager;
+import org.briarproject.briar.api.autodelete.AutoDeleteManager;
 import org.briarproject.briar.api.client.MessageTracker;
 import org.briarproject.briar.api.client.SessionId;
+import org.briarproject.briar.api.conversation.ConversationManager;
 import org.briarproject.briar.api.identity.AuthorInfo;
 import org.briarproject.briar.api.identity.AuthorManager;
 import org.briarproject.briar.api.introduction.IntroductionResponse;
@@ -31,6 +36,9 @@ import java.util.Map;
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 
+import static org.briarproject.briar.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
+import static org.briarproject.briar.api.introduction.IntroductionManager.CLIENT_ID;
+import static org.briarproject.briar.api.introduction.IntroductionManager.MAJOR_VERSION;
 import static org.briarproject.briar.introduction.MessageType.ABORT;
 import static org.briarproject.briar.introduction.MessageType.ACCEPT;
 import static org.briarproject.briar.introduction.MessageType.ACTIVATE;
@@ -40,7 +48,7 @@ import static org.briarproject.briar.introduction.MessageType.REQUEST;
 
 @Immutable
 @NotNullByDefault
-abstract class AbstractProtocolEngine<S extends Session>
+abstract class AbstractProtocolEngine<S extends Session<?>>
 		implements ProtocolEngine<S> {
 
 	protected final DatabaseComponent db;
@@ -52,6 +60,9 @@ abstract class AbstractProtocolEngine<S extends Session>
 	protected final AuthorManager authorManager;
 	protected final MessageParser messageParser;
 	protected final MessageEncoder messageEncoder;
+	protected final ClientVersioningManager clientVersioningManager;
+	protected final AutoDeleteManager autoDeleteManager;
+	protected final ConversationManager conversationManager;
 	protected final Clock clock;
 
 	AbstractProtocolEngine(
@@ -64,6 +75,9 @@ abstract class AbstractProtocolEngine<S extends Session>
 			AuthorManager authorManager,
 			MessageParser messageParser,
 			MessageEncoder messageEncoder,
+			ClientVersioningManager clientVersioningManager,
+			AutoDeleteManager autoDeleteManager,
+			ConversationManager conversationManager,
 			Clock clock) {
 		this.db = db;
 		this.clientHelper = clientHelper;
@@ -74,16 +88,29 @@ abstract class AbstractProtocolEngine<S extends Session>
 		this.authorManager = authorManager;
 		this.messageParser = messageParser;
 		this.messageEncoder = messageEncoder;
+		this.clientVersioningManager = clientVersioningManager;
+		this.autoDeleteManager = autoDeleteManager;
+		this.conversationManager = conversationManager;
 		this.clock = clock;
 	}
 
 	Message sendRequestMessage(Transaction txn, PeerSession s,
 			long timestamp, Author author, @Nullable String text)
 			throws DbException {
-		Message m = messageEncoder
-				.encodeRequestMessage(s.getContactGroupId(), timestamp,
-						s.getLastLocalMessageId(), author, text);
-		sendMessage(txn, REQUEST, s.getSessionId(), m, true);
+		Message m;
+		ContactId c = getContactId(txn, s.getContactGroupId());
+		if (contactSupportsAutoDeletion(txn, c)) {
+			long timer = autoDeleteManager.getAutoDeleteTimer(txn, c,
+					timestamp);
+			m = messageEncoder.encodeRequestMessage(s.getContactGroupId(),
+					timestamp, s.getLastLocalMessageId(), author, text, timer);
+			sendMessage(txn, REQUEST, s.getSessionId(), m, true, timer);
+		} else {
+			m = messageEncoder.encodeRequestMessage(s.getContactGroupId(),
+					timestamp, s.getLastLocalMessageId(), author, text);
+			sendMessage(txn, REQUEST, s.getSessionId(), m, true,
+					NO_AUTO_DELETE_TIMER);
+		}
 		return m;
 	}
 
@@ -91,21 +118,43 @@ abstract class AbstractProtocolEngine<S extends Session>
 			PublicKey ephemeralPublicKey, long acceptTimestamp,
 			Map<TransportId, TransportProperties> transportProperties,
 			boolean visible) throws DbException {
-		Message m = messageEncoder
-				.encodeAcceptMessage(s.getContactGroupId(), timestamp,
-						s.getLastLocalMessageId(), s.getSessionId(),
-						ephemeralPublicKey, acceptTimestamp,
-						transportProperties);
-		sendMessage(txn, ACCEPT, s.getSessionId(), m, visible);
+		Message m;
+		ContactId c = getContactId(txn, s.getContactGroupId());
+		if (contactSupportsAutoDeletion(txn, c)) {
+			long timer = autoDeleteManager.getAutoDeleteTimer(txn, c,
+					timestamp);
+			m = messageEncoder.encodeAcceptMessage(s.getContactGroupId(),
+					timestamp, s.getLastLocalMessageId(), s.getSessionId(),
+					ephemeralPublicKey, acceptTimestamp, transportProperties,
+					timer);
+			sendMessage(txn, ACCEPT, s.getSessionId(), m, visible, timer);
+		} else {
+			m = messageEncoder.encodeAcceptMessage(s.getContactGroupId(),
+					timestamp, s.getLastLocalMessageId(), s.getSessionId(),
+					ephemeralPublicKey, acceptTimestamp, transportProperties);
+			sendMessage(txn, ACCEPT, s.getSessionId(), m, visible,
+					NO_AUTO_DELETE_TIMER);
+		}
 		return m;
 	}
 
 	Message sendDeclineMessage(Transaction txn, PeerSession s, long timestamp,
 			boolean visible) throws DbException {
-		Message m = messageEncoder
-				.encodeDeclineMessage(s.getContactGroupId(), timestamp,
-						s.getLastLocalMessageId(), s.getSessionId());
-		sendMessage(txn, DECLINE, s.getSessionId(), m, visible);
+		Message m;
+		ContactId c = getContactId(txn, s.getContactGroupId());
+		if (contactSupportsAutoDeletion(txn, c)) {
+			long timer = autoDeleteManager.getAutoDeleteTimer(txn, c,
+					timestamp);
+			m = messageEncoder.encodeDeclineMessage(s.getContactGroupId(),
+					timestamp, s.getLastLocalMessageId(), s.getSessionId(),
+					timer);
+			sendMessage(txn, DECLINE, s.getSessionId(), m, visible, timer);
+		} else {
+			m = messageEncoder.encodeDeclineMessage(s.getContactGroupId(),
+					timestamp, s.getLastLocalMessageId(), s.getSessionId());
+			sendMessage(txn, DECLINE, s.getSessionId(), m, visible,
+					NO_AUTO_DELETE_TIMER);
+		}
 		return m;
 	}
 
@@ -115,7 +164,8 @@ abstract class AbstractProtocolEngine<S extends Session>
 				.encodeAuthMessage(s.getContactGroupId(), timestamp,
 						s.getLastLocalMessageId(), s.getSessionId(), mac,
 						signature);
-		sendMessage(txn, AUTH, s.getSessionId(), m, false);
+		sendMessage(txn, AUTH, s.getSessionId(), m, false,
+				NO_AUTO_DELETE_TIMER);
 		return m;
 	}
 
@@ -124,7 +174,8 @@ abstract class AbstractProtocolEngine<S extends Session>
 		Message m = messageEncoder
 				.encodeActivateMessage(s.getContactGroupId(), timestamp,
 						s.getLastLocalMessageId(), s.getSessionId(), mac);
-		sendMessage(txn, ACTIVATE, s.getSessionId(), m, false);
+		sendMessage(txn, ACTIVATE, s.getSessionId(), m, false,
+				NO_AUTO_DELETE_TIMER);
 		return m;
 	}
 
@@ -133,16 +184,17 @@ abstract class AbstractProtocolEngine<S extends Session>
 		Message m = messageEncoder
 				.encodeAbortMessage(s.getContactGroupId(), timestamp,
 						s.getLastLocalMessageId(), s.getSessionId());
-		sendMessage(txn, ABORT, s.getSessionId(), m, false);
+		sendMessage(txn, ABORT, s.getSessionId(), m, false,
+				NO_AUTO_DELETE_TIMER);
 		return m;
 	}
 
 	private void sendMessage(Transaction txn, MessageType type,
-			SessionId sessionId, Message m, boolean visibleInConversation)
-			throws DbException {
-		BdfDictionary meta = messageEncoder
-				.encodeMetadata(type, sessionId, m.getTimestamp(), true, true,
-						visibleInConversation);
+			SessionId sessionId, Message m, boolean visibleInConversation,
+			long autoDeleteTimer) throws DbException {
+		BdfDictionary meta = messageEncoder.encodeMetadata(type, sessionId,
+				m.getTimestamp(), true, true, visibleInConversation,
+				autoDeleteTimer);
 		try {
 			clientHelper.addLocalMessage(txn, m, meta, true, false);
 		} catch (FormatException e) {
@@ -150,9 +202,10 @@ abstract class AbstractProtocolEngine<S extends Session>
 		}
 	}
 
-	void broadcastIntroductionResponseReceivedEvent(Transaction txn, Session s,
-			AuthorId sender, Author otherAuthor, AbstractIntroductionMessage m,
-			boolean canSucceed) throws DbException {
+	void broadcastIntroductionResponseReceivedEvent(Transaction txn,
+			Session<?> s, AuthorId sender, Author otherAuthor,
+			AbstractIntroductionMessage m, boolean canSucceed)
+			throws DbException {
 		AuthorId localAuthorId = identityManager.getLocalAuthor(txn).getId();
 		Contact c = contactManager.getContact(txn, sender, localAuthorId);
 		AuthorInfo otherAuthorInfo =
@@ -161,7 +214,8 @@ abstract class AbstractProtocolEngine<S extends Session>
 				new IntroductionResponse(m.getMessageId(), m.getGroupId(),
 						m.getTimestamp(), false, false, false, false,
 						s.getSessionId(), m instanceof AcceptMessage,
-						otherAuthor, otherAuthorInfo, s.getRole(), canSucceed);
+						otherAuthor, otherAuthorInfo, s.getRole(), canSucceed,
+						m.getAutoDeleteTimer());
 		IntroductionResponseReceivedEvent e =
 				new IntroductionResponseReceivedEvent(response, c.getId());
 		txn.attach(e);
@@ -184,14 +238,33 @@ abstract class AbstractProtocolEngine<S extends Session>
 		return !dependency.equals(lastRemoteMessageId);
 	}
 
-	long getLocalTimestamp(long localTimestamp, long requestTimestamp) {
-		return Math.max(
-				clock.currentTimeMillis(),
-				Math.max(
-						localTimestamp,
-						requestTimestamp
-				) + 1
-		);
+	long getTimestampForOutgoingMessage(Transaction txn, GroupId contactGroupId)
+			throws DbException {
+		ContactId c = getContactId(txn, contactGroupId);
+		return conversationManager.getTimestampForOutgoingMessage(txn, c);
 	}
 
+	void receiveAutoDeleteTimer(Transaction txn, AbstractIntroductionMessage m)
+			throws DbException {
+		ContactId c = getContactId(txn, m.getGroupId());
+		autoDeleteManager.receiveAutoDeleteTimer(txn, c, m.getAutoDeleteTimer(),
+				m.getTimestamp());
+	}
+
+	private ContactId getContactId(Transaction txn, GroupId contactGroupId)
+			throws DbException {
+		try {
+			return clientHelper.getContactId(txn, contactGroupId);
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
+	private boolean contactSupportsAutoDeletion(Transaction txn, ContactId c)
+			throws DbException {
+		int minorVersion = clientVersioningManager.getClientMinorVersion(txn, c,
+				CLIENT_ID, MAJOR_VERSION);
+		// Auto-delete was added in client version 0.1
+		return minorVersion >= 1;
+	}
 }

briar-core/src/main/java/org/briarproject/briar/introduction/AcceptMessage.java

@@ -26,8 +26,10 @@ class AcceptMessage extends AbstractIntroductionMessage {
 			long timestamp, @Nullable MessageId previousMessageId,
 			SessionId sessionId, PublicKey ephemeralPublicKey,
 			long acceptTimestamp,
-			Map<TransportId, TransportProperties> transportProperties) {
-		super(messageId, groupId, timestamp, previousMessageId);
+			Map<TransportId, TransportProperties> transportProperties,
+			long autoDeleteTimer) {
+		super(messageId, groupId, timestamp, previousMessageId,
+				autoDeleteTimer);
 		this.sessionId = sessionId;
 		this.ephemeralPublicKey = ephemeralPublicKey;
 		this.acceptTimestamp = acceptTimestamp;

briar-core/src/main/java/org/briarproject/briar/introduction/ActivateMessage.java

@@ -7,6 +7,8 @@ import org.briarproject.briar.api.client.SessionId;
 
 import javax.annotation.concurrent.Immutable;
 
+import static org.briarproject.briar.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
+
 @Immutable
 @NotNullByDefault
 class ActivateMessage extends AbstractIntroductionMessage {
@@ -17,7 +19,8 @@ class ActivateMessage extends AbstractIntroductionMessage {
 	protected ActivateMessage(MessageId messageId, GroupId groupId,
 			long timestamp, MessageId previousMessageId, SessionId sessionId,
 			byte[] mac) {
-		super(messageId, groupId, timestamp, previousMessageId);
+		super(messageId, groupId, timestamp, previousMessageId,
+				NO_AUTO_DELETE_TIMER);
 		this.sessionId = sessionId;
 		this.mac = mac;
 	}

briar-core/src/main/java/org/briarproject/briar/introduction/AuthMessage.java

@@ -7,6 +7,8 @@ import org.briarproject.briar.api.client.SessionId;
 
 import javax.annotation.concurrent.Immutable;
 
+import static org.briarproject.briar.api.autodelete.AutoDeleteConstants.NO_AUTO_DELETE_TIMER;
+
 @Immutable
 @NotNullByDefault
 class AuthMessage extends AbstractIntroductionMessage {
@@ -17,7 +19,8 @@ class AuthMessage extends AbstractIntroductionMessage {
 	protected AuthMessage(MessageId messageId, GroupId groupId,
 			long timestamp, MessageId previousMessageId, SessionId sessionId,
 			byte[] mac, byte[] signature) {
-		super(messageId, groupId, timestamp, previousMessageId);
+		super(messageId, groupId, timestamp, previousMessageId,
+				NO_AUTO_DELETE_TIMER);
 		this.sessionId = sessionId;
 		this.mac = mac;
 		this.signature = signature;