Merge branch '2181-implement-sync-client-for-mailbox-props' into 'master'

Implement sync client for mailbox properties

Closes #2181

See merge request briar/briar!1591

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

@@ -6,14 +6,14 @@ import javax.annotation.concurrent.ThreadSafe;
 
 @ThreadSafe
 @NotNullByDefault
-public abstract class UniqueId extends Bytes {
+public class UniqueId extends Bytes {
 
 	/**
 	 * The length of a unique identifier in bytes.
 	 */
 	public static final int LENGTH = 32;
 
-	protected UniqueId(byte[] id) {
+	public UniqueId(byte[] id) {
 		super(id);
 		if (id.length != LENGTH) throw new IllegalArgumentException();
 	}

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

@@ -9,6 +9,7 @@ import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.mailbox.MailboxPropertiesUpdate;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.properties.TransportProperties;
@@ -20,6 +21,8 @@ import java.security.GeneralSecurityException;
 import java.util.Collection;
 import java.util.Map;
 
+import javax.annotation.Nullable;
+
 @NotNullByDefault
 public interface ClientHelper {
 
@@ -123,6 +126,18 @@ public interface ClientHelper {
 	Map<TransportId, TransportProperties> parseAndValidateTransportPropertiesMap(
 			BdfDictionary properties) throws FormatException;
 
+	/**
+	 * Parse and validate the property dictionary of a Mailbox property update
+	 * message.
+	 *
+	 * @return the properties for using the Mailbox, or null if there is no
+	 * Mailbox available
+	 * @throws FormatException if the properties are not valid
+	 */
+	@Nullable
+	MailboxPropertiesUpdate parseAndValidateMailboxPropertiesUpdate(
+			BdfDictionary properties) throws FormatException;
+
 	/**
 	 * Retrieves the contact ID from the group metadata of the given contact
 	 * group.

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

@@ -3,7 +3,6 @@ package org.briarproject.bramble.api.contact;
 import org.briarproject.bramble.api.UniqueId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
-import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 
 /**
@@ -17,9 +16,4 @@ public class PendingContactId extends UniqueId {
 	public PendingContactId(byte[] id) {
 		super(id);
 	}
-
-	@Override
-	public boolean equals(@Nullable Object o) {
-		return o instanceof PendingContactId && super.equals(o);
-	}
 }

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

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.api.crypto;
 
+import org.briarproject.bramble.api.UniqueId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.security.GeneralSecurityException;
@@ -10,6 +11,8 @@ import javax.annotation.Nullable;
 @NotNullByDefault
 public interface CryptoComponent {
 
+	UniqueId generateUniqueId();
+
 	SecretKey generateSecretKey();
 
 	SecureRandom getSecureRandom();
@@ -172,9 +175,11 @@ public interface CryptoComponent {
 	String asciiArmour(byte[] b, int lineLength);
 
 	/**
-	 * Encode the onion/hidden service address given its public key. As
+	 * Encode the Onion given its public key. Specified here:
-	 * specified here: https://gitweb.torproject.org/torspec.git/tree/rend-spec-v3.txt?id=29245fd5#n2135
+	 * https://gitweb.torproject.org/torspec.git/tree/rend-spec-v3.txt?id=29245fd5#n2135
+	 *
+	 * @return the encoded onion, base32 chars
 	 */
-	String encodeOnionAddress(byte[] publicKey);
+	String encodeOnion(byte[] publicKey);
 
 }

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

@@ -21,9 +21,4 @@ public class AuthorId extends UniqueId {
 	public AuthorId(byte[] id) {
 		super(id);
 	}
-
-	@Override
-	public boolean equals(Object o) {
-		return o instanceof AuthorId && super.equals(o);
-	}
 }

bramble-api/src/main/java/org/briarproject/bramble/api/mailbox/MailboxProperties.java

@@ -23,6 +23,11 @@ public class MailboxProperties {
 		return baseUrl;
 	}
 
+	public String getOnion() {
+		return baseUrl.replaceFirst("^http://", "")
+				.replaceFirst("\\.onion$", "");
+	}
+
 	public MailboxAuthToken getAuthToken() {
 		return authToken;
 	}

bramble-api/src/main/java/org/briarproject/bramble/api/mailbox/MailboxPropertiesUpdate.java

@@ -0,0 +1,41 @@
+package org.briarproject.bramble.api.mailbox;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+public class MailboxPropertiesUpdate {
+
+	private final String onion;
+	private final MailboxAuthToken authToken;
+	private final MailboxFolderId inboxId;
+	private final MailboxFolderId outboxId;
+
+	public MailboxPropertiesUpdate(String onion,
+			MailboxAuthToken authToken, MailboxFolderId inboxId,
+			MailboxFolderId outboxId) {
+		this.onion = onion;
+		this.authToken = authToken;
+		this.inboxId = inboxId;
+		this.outboxId = outboxId;
+	}
+
+	public String getOnion() {
+		return onion;
+	}
+
+	public MailboxAuthToken getAuthToken() {
+		return authToken;
+	}
+
+	public MailboxFolderId getInboxId() {
+		return inboxId;
+	}
+
+	public MailboxFolderId getOutboxId() {
+		return outboxId;
+	}
+
+}

bramble-api/src/main/java/org/briarproject/bramble/api/mailbox/MailboxPropertyManager.java

@@ -0,0 +1,67 @@
+package org.briarproject.bramble.api.mailbox;
+
+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;
+
+import javax.annotation.Nullable;
+
+@NotNullByDefault
+public interface MailboxPropertyManager {
+
+	/**
+	 * The unique ID of the mailbox property client.
+	 */
+	ClientId CLIENT_ID =
+			new ClientId("org.briarproject.bramble.mailbox.properties");
+
+	/**
+	 * The current major version of the mailbox property client.
+	 */
+	int MAJOR_VERSION = 0;
+
+	/**
+	 * The current minor version of the mailbox property client.
+	 */
+	int MINOR_VERSION = 0;
+
+	/**
+	 * The number of properties required for a (non-empty) update message.
+	 */
+	int PROP_COUNT = 4;
+
+	/**
+	 * The required properties of a non-empty update message.
+	 */
+	String PROP_KEY_ONION = "onion";
+	String PROP_KEY_AUTHTOKEN = "authToken";
+	String PROP_KEY_INBOXID = "inboxId";
+	String PROP_KEY_OUTBOXID = "outboxId";
+
+	/**
+	 * Length of the Onion property.
+	 */
+	int PROP_ONION_LENGTH = 56;
+
+	/**
+	 * Message metadata key for the version number of a local or remote update,
+	 * as a BDF long.
+	 */
+	String MSG_KEY_VERSION = "version";
+
+	/**
+	 * Message metadata key for whether an update is local or remote, as a BDF
+	 * boolean.
+	 */
+	String MSG_KEY_LOCAL = "local";
+
+	@Nullable
+	MailboxPropertiesUpdate getLocalProperties(Transaction txn, ContactId c)
+			throws DbException;
+
+	@Nullable
+	MailboxPropertiesUpdate getRemoteProperties(Transaction txn, ContactId c)
+			throws DbException;
+}

bramble-api/src/main/java/org/briarproject/bramble/api/mailbox/MailboxSettingsManager.java

@@ -1,8 +1,10 @@
 package org.briarproject.bramble.api.mailbox;
 
 import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import javax.annotation.Nullable;
@@ -10,6 +12,13 @@ import javax.annotation.Nullable;
 @NotNullByDefault
 public interface MailboxSettingsManager {
 
+	/**
+	 * Registers a hook to be called when a mailbox has been paired or unpaired.
+	 * This method should be called before
+	 * {@link LifecycleManager#startServices(SecretKey)}.
+	 */
+	void registerMailboxHook(MailboxHook hook);
+
 	@Nullable
 	MailboxProperties getOwnMailboxProperties(Transaction txn)
 			throws DbException;
@@ -30,4 +39,22 @@ public interface MailboxSettingsManager {
 
 	@Nullable
 	String getPendingUpload(Transaction txn, ContactId id) throws DbException;
+
+	interface MailboxHook {
+		/**
+		 * Called when Briar is paired with a mailbox
+		 *
+		 * @param txn A read-write transaction
+		 * @param ownOnion Our new mailbox's onion (56 base32 chars)
+		 */
+		void mailboxPaired(Transaction txn, String ownOnion)
+				throws DbException;
+
+		/**
+		 * Called when the mailbox is unpaired
+		 *
+		 * @param txn A read-write transaction
+		 */
+		void mailboxUnpaired(Transaction txn) throws DbException;
+	}
 }

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

@@ -20,9 +20,4 @@ public class GroupId extends UniqueId {
 	public GroupId(byte[] id) {
 		super(id);
 	}
-
-	@Override
-	public boolean equals(Object o) {
-		return o instanceof GroupId && super.equals(o);
-	}
 }

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

@@ -27,9 +27,4 @@ public class MessageId extends UniqueId {
 	public MessageId(byte[] id) {
 		super(id);
 	}
-
-	@Override
-	public boolean equals(Object o) {
-		return o instanceof MessageId && super.equals(o);
-	}
 }

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

@@ -16,6 +16,7 @@ import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.identity.Identity;
 import org.briarproject.bramble.api.identity.LocalAuthor;
+import org.briarproject.bramble.api.mailbox.MailboxPropertiesUpdate;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.sync.ClientId;
@@ -39,6 +40,8 @@ import java.util.Map;
 import java.util.Random;
 import java.util.concurrent.atomic.AtomicInteger;
 
+import javax.annotation.Nullable;
+
 import static java.util.Arrays.asList;
 import static org.briarproject.bramble.api.crypto.CryptoConstants.MAX_AGREEMENT_PUBLIC_KEY_BYTES;
 import static org.briarproject.bramble.api.crypto.CryptoConstants.MAX_SIGNATURE_PUBLIC_KEY_BYTES;
@@ -271,4 +274,17 @@ public class TestUtils {
 		return optionalTests != null &&
 				asList(optionalTests.split(",")).contains(testClass.getName());
 	}
+
+	public static boolean mailboxPropertiesUpdateEqual(
+			@Nullable MailboxPropertiesUpdate a,
+			@Nullable MailboxPropertiesUpdate b) {
+		if (a == null || b == null) {
+			return a == b;
+		}
+		return a.getOnion().equals(b.getOnion()) &&
+				a.getAuthToken().equals(b.getAuthToken()) &&
+				a.getInboxId().equals(b.getInboxId()) &&
+				a.getOutboxId().equals(b.getOutboxId());
+	}
+
 }

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

@@ -1,6 +1,7 @@
 package org.briarproject.bramble.client;
 
 import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.UniqueId;
 import org.briarproject.bramble.api.client.ClientHelper;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
@@ -22,6 +23,9 @@ import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorFactory;
+import org.briarproject.bramble.api.mailbox.MailboxAuthToken;
+import org.briarproject.bramble.api.mailbox.MailboxFolderId;
+import org.briarproject.bramble.api.mailbox.MailboxPropertiesUpdate;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.properties.TransportProperties;
@@ -29,6 +33,7 @@ import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageFactory;
 import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.bramble.util.Base32;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
@@ -39,6 +44,7 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.Map.Entry;
 
+import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
@@ -46,6 +52,12 @@ import static org.briarproject.bramble.api.client.ContactGroupConstants.GROUP_KE
 import static org.briarproject.bramble.api.identity.Author.FORMAT_VERSION;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.PROP_COUNT;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.PROP_KEY_AUTHTOKEN;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.PROP_KEY_INBOXID;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.PROP_KEY_ONION;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.PROP_KEY_OUTBOXID;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.PROP_ONION_LENGTH;
 import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MAX_PROPERTIES_PER_TRANSPORT;
 import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MAX_PROPERTY_LENGTH;
 import static org.briarproject.bramble.util.ValidationUtils.checkLength;
@@ -399,6 +411,35 @@ class ClientHelperImpl implements ClientHelper {
 		return tpMap;
 	}
 
+	@Override
+	@Nullable
+	public MailboxPropertiesUpdate parseAndValidateMailboxPropertiesUpdate(
+			BdfDictionary properties) throws FormatException {
+		if (properties.isEmpty()) {
+			return null;
+		}
+		// Accepting more props than we need, for forward compatibility
+		if (properties.size() < PROP_COUNT) {
+			throw new FormatException();
+		}
+		String onion = properties.getString(PROP_KEY_ONION);
+		checkLength(onion, PROP_ONION_LENGTH);
+		try {
+			Base32.decode(onion, true);
+		} catch (IllegalArgumentException e) {
+			throw new FormatException();
+		}
+		byte[] authToken = properties.getRaw(PROP_KEY_AUTHTOKEN);
+		checkLength(authToken, UniqueId.LENGTH);
+		byte[] inboxId = properties.getRaw(PROP_KEY_INBOXID);
+		checkLength(inboxId, UniqueId.LENGTH);
+		byte[] outboxId = properties.getRaw(PROP_KEY_OUTBOXID);
+		checkLength(outboxId, UniqueId.LENGTH);
+		return new MailboxPropertiesUpdate(onion,
+				new MailboxAuthToken(authToken), new MailboxFolderId(inboxId),
+				new MailboxFolderId(outboxId));
+	}
+
 	@Override
 	public ContactId getContactId(Transaction txn, GroupId contactGroupId)
 			throws DbException {

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

@@ -8,6 +8,7 @@ import org.bouncycastle.crypto.CryptoException;
 import org.bouncycastle.crypto.Digest;
 import org.bouncycastle.crypto.digests.Blake2bDigest;
 import org.bouncycastle.crypto.digests.SHA3Digest;
+import org.briarproject.bramble.api.UniqueId;
 import org.briarproject.bramble.api.crypto.AgreementPrivateKey;
 import org.briarproject.bramble.api.crypto.AgreementPublicKey;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
@@ -41,6 +42,7 @@ import javax.inject.Inject;
 
 import static java.lang.System.arraycopy;
 import static java.util.logging.Level.INFO;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.crypto.CryptoConstants.KEY_TYPE_AGREEMENT;
 import static org.briarproject.bramble.api.crypto.CryptoConstants.KEY_TYPE_SIGNATURE;
 import static org.briarproject.bramble.api.crypto.DecryptionResult.INVALID_CIPHERTEXT;
@@ -54,7 +56,7 @@ import static org.briarproject.bramble.util.LogUtils.now;
 class CryptoComponentImpl implements CryptoComponent {
 
 	private static final Logger LOG =
-			Logger.getLogger(CryptoComponentImpl.class.getName());
+			getLogger(CryptoComponentImpl.class.getName());
 
 	private static final int SIGNATURE_KEY_PAIR_BITS = 256;
 	private static final int STORAGE_IV_BYTES = 24; // 196 bits
@@ -128,6 +130,13 @@ class CryptoComponentImpl implements CryptoComponent {
 		}
 	}
 
+	@Override
+	public UniqueId generateUniqueId() {
+		byte[] b = new byte[UniqueId.LENGTH];
+		secureRandom.nextBytes(b);
+		return new UniqueId(b);
+	}
+
 	@Override
 	public SecretKey generateSecretKey() {
 		byte[] b = new byte[SecretKey.LENGTH];
@@ -449,7 +458,7 @@ class CryptoComponentImpl implements CryptoComponent {
 	}
 
 	@Override
-	public String encodeOnionAddress(byte[] publicKey) {
+	public String encodeOnion(byte[] publicKey) {
 		Digest digest = new SHA3Digest(256);
 		byte[] label = ".onion checksum".getBytes(Charset.forName("US-ASCII"));
 		digest.update(label, 0, label.length);

bramble-core/src/main/java/org/briarproject/bramble/mailbox/MailboxModule.java

@@ -1,16 +1,36 @@
 package org.briarproject.bramble.mailbox;
 
+import org.briarproject.bramble.api.client.ClientHelper;
+import org.briarproject.bramble.api.contact.ContactManager;
+import org.briarproject.bramble.api.data.MetadataEncoder;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.mailbox.MailboxManager;
+import org.briarproject.bramble.api.mailbox.MailboxPropertyManager;
 import org.briarproject.bramble.api.mailbox.MailboxSettingsManager;
+import org.briarproject.bramble.api.sync.validation.ValidationManager;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.versioning.ClientVersioningManager;
 
+import javax.inject.Inject;
 import javax.inject.Singleton;
 
 import dagger.Module;
 import dagger.Provides;
 
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.CLIENT_ID;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.MAJOR_VERSION;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.MINOR_VERSION;
+
 @Module
 public class MailboxModule {
 
+	public static class EagerSingletons {
+		@Inject
+		MailboxPropertyValidator mailboxPropertyValidator;
+		@Inject
+		MailboxPropertyManager mailboxPropertyManager;
+	}
+
 	@Provides
 	@Singleton
 	MailboxManager providesMailboxManager(MailboxManagerImpl mailboxManager) {
@@ -33,4 +53,34 @@ public class MailboxModule {
 	MailboxApi providesMailboxApi(MailboxApiImpl mailboxApi) {
 		return mailboxApi;
 	}
+
+	@Provides
+	@Singleton
+	MailboxPropertyValidator provideMailboxPropertyValidator(
+			ValidationManager validationManager, ClientHelper clientHelper,
+			MetadataEncoder metadataEncoder, Clock clock) {
+		MailboxPropertyValidator validator = new MailboxPropertyValidator(
+				clientHelper, metadataEncoder, clock);
+		validationManager.registerMessageValidator(CLIENT_ID, MAJOR_VERSION,
+				validator);
+		return validator;
+	}
+
+	@Provides
+	@Singleton
+	MailboxPropertyManager provideMailboxPropertyManager(
+			LifecycleManager lifecycleManager,
+			ValidationManager validationManager, ContactManager contactManager,
+			ClientVersioningManager clientVersioningManager,
+			MailboxSettingsManager mailboxSettingsManager,
+			MailboxPropertyManagerImpl mailboxPropertyManager) {
+		lifecycleManager.registerOpenDatabaseHook(mailboxPropertyManager);
+		validationManager.registerIncomingMessageHook(CLIENT_ID, MAJOR_VERSION,
+				mailboxPropertyManager);
+		contactManager.registerContactHook(mailboxPropertyManager);
+		clientVersioningManager.registerClient(CLIENT_ID, MAJOR_VERSION,
+				MINOR_VERSION, mailboxPropertyManager);
+		mailboxSettingsManager.registerMailboxHook(mailboxPropertyManager);
+		return mailboxPropertyManager;
+	}
 }

bramble-core/src/main/java/org/briarproject/bramble/mailbox/MailboxPairingTaskImpl.java

@@ -162,8 +162,8 @@ class MailboxPairingTaskImpl implements MailboxPairingTask {
 		}
 		LOG.info("QR code is valid");
 		byte[] onionPubKey = Arrays.copyOfRange(bytes, 1, 33);
-		String onionAddress = crypto.encodeOnionAddress(onionPubKey);
+		String onion = crypto.encodeOnion(onionPubKey);
-		String baseUrl = "http://" + onionAddress + ".onion";
+		String baseUrl = "http://" + onion + ".onion";
 		byte[] tokenBytes = Arrays.copyOfRange(bytes, 33, 65);
 		MailboxAuthToken setupToken = new MailboxAuthToken(tokenBytes);
 		return new MailboxProperties(baseUrl, setupToken, true);

bramble-core/src/main/java/org/briarproject/bramble/mailbox/MailboxPropertyManagerImpl.java

@@ -0,0 +1,296 @@
+package org.briarproject.bramble.mailbox;
+
+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.contact.ContactManager.ContactHook;
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.data.BdfDictionary;
+import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.data.MetadataParser;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Metadata;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager.OpenDatabaseHook;
+import org.briarproject.bramble.api.mailbox.MailboxAuthToken;
+import org.briarproject.bramble.api.mailbox.MailboxFolderId;
+import org.briarproject.bramble.api.mailbox.MailboxProperties;
+import org.briarproject.bramble.api.mailbox.MailboxPropertiesUpdate;
+import org.briarproject.bramble.api.mailbox.MailboxPropertyManager;
+import org.briarproject.bramble.api.mailbox.MailboxSettingsManager;
+import org.briarproject.bramble.api.mailbox.MailboxSettingsManager.MailboxHook;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.Group;
+import org.briarproject.bramble.api.sync.Group.Visibility;
+import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.sync.InvalidMessageException;
+import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.bramble.api.sync.validation.IncomingMessageHook;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.versioning.ClientVersioningManager;
+import org.briarproject.bramble.api.versioning.ClientVersioningManager.ClientVersioningHook;
+
+import java.util.Map;
+import java.util.Map.Entry;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+
+import static org.briarproject.bramble.api.sync.validation.IncomingMessageHook.DeliveryAction.ACCEPT_DO_NOT_SHARE;
+
+@NotNullByDefault
+class MailboxPropertyManagerImpl implements MailboxPropertyManager,
+		OpenDatabaseHook, ContactHook, ClientVersioningHook,
+		IncomingMessageHook, MailboxHook {
+
+	private final DatabaseComponent db;
+	private final ClientHelper clientHelper;
+	private final ClientVersioningManager clientVersioningManager;
+	private final MetadataParser metadataParser;
+	private final ContactGroupFactory contactGroupFactory;
+	private final Clock clock;
+	private final MailboxSettingsManager mailboxSettingsManager;
+	private final ContactManager contactManager;
+	private final CryptoComponent crypto;
+	private final Group localGroup;
+
+	@Inject
+	MailboxPropertyManagerImpl(DatabaseComponent db, ClientHelper clientHelper,
+			ClientVersioningManager clientVersioningManager,
+			MetadataParser metadataParser,
+			ContactGroupFactory contactGroupFactory, Clock clock,
+			MailboxSettingsManager mailboxSettingsManager,
+			ContactManager contactManager,
+			CryptoComponent crypto) {
+		this.db = db;
+		this.clientHelper = clientHelper;
+		this.clientVersioningManager = clientVersioningManager;
+		this.metadataParser = metadataParser;
+		this.contactGroupFactory = contactGroupFactory;
+		this.clock = clock;
+		this.mailboxSettingsManager = mailboxSettingsManager;
+		this.contactManager = contactManager;
+		this.crypto = crypto;
+		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 {
+		// Create a group to share with the contact
+		Group g = getContactGroup(c);
+		db.addGroup(txn, g);
+		// Apply the client's visibility to the contact group
+		Visibility client = clientVersioningManager
+				.getClientVisibility(txn, c.getId(), CLIENT_ID, MAJOR_VERSION);
+		db.setGroupVisibility(txn, c.getId(), g.getId(), client);
+		// If we are paired, create and send props to the newly added contact
+		MailboxProperties ownProps =
+				mailboxSettingsManager.getOwnMailboxProperties(txn);
+		if (ownProps != null) {
+			createAndSendProperties(txn, c, ownProps.getOnion());
+		}
+	}
+
+	@Override
+	public void removingContact(Transaction txn, Contact c) throws DbException {
+		db.removeGroup(txn, getContactGroup(c));
+	}
+
+	@Override
+	public void mailboxPaired(Transaction txn, String ownOnion)
+			throws DbException {
+		for (Contact c : contactManager.getContacts()) {
+			createAndSendProperties(txn, c, ownOnion);
+		}
+	}
+
+	@Override
+	public void mailboxUnpaired(Transaction txn) throws DbException {
+		for (Contact c : contactManager.getContacts()) {
+			sendEmptyProperties(txn, c);
+		}
+	}
+
+	@Override
+	public void onClientVisibilityChanging(Transaction txn, Contact c,
+			Visibility v) throws DbException {
+		// Apply the client's visibility to the contact group
+		Group g = getContactGroup(c);
+		db.setGroupVisibility(txn, c.getId(), g.getId(), v);
+	}
+
+	@Override
+	public DeliveryAction incomingMessage(Transaction txn, Message m,
+			Metadata meta) throws DbException, InvalidMessageException {
+		try {
+			BdfDictionary d = metadataParser.parse(meta);
+			// Get latest non-local update in the same group (from same contact)
+			LatestUpdate latest = findLatest(txn, m.getGroupId(), false);
+			if (latest != null) {
+				if (d.getLong(MSG_KEY_VERSION) > latest.version) {
+					db.deleteMessage(txn, latest.messageId);
+					db.deleteMessageMetadata(txn, latest.messageId);
+				} else {
+					// Delete this update, we already have a newer one
+					db.deleteMessage(txn, m.getId());
+					db.deleteMessageMetadata(txn, m.getId());
+					return ACCEPT_DO_NOT_SHARE;
+				}
+			}
+			// TODO should probably broadcast an event that a contact's mailbox
+			//  properties were updated
+		} catch (FormatException e) {
+			throw new InvalidMessageException(e);
+		}
+		return ACCEPT_DO_NOT_SHARE;
+	}
+
+	@Override
+	@Nullable
+	public MailboxPropertiesUpdate getLocalProperties(Transaction txn,
+			ContactId c) throws DbException {
+		return getProperties(txn, db.getContact(txn, c), true);
+	}
+
+	@Override
+	@Nullable
+	public MailboxPropertiesUpdate getRemoteProperties(Transaction txn,
+			ContactId c) throws DbException {
+		return getProperties(txn, db.getContact(txn, c), false);
+	}
+
+	/**
+	 * Creates and sends an update message to the given contact. The message
+	 * holds our own mailbox's onion, and generated unique properties. All of
+	 * which the contact needs to communicate with our Mailbox.
+	 */
+	private void createAndSendProperties(Transaction txn,
+			Contact c, String ownOnion) throws DbException {
+		MailboxPropertiesUpdate p = new MailboxPropertiesUpdate(ownOnion,
+				new MailboxAuthToken(crypto.generateUniqueId().getBytes()),
+				new MailboxFolderId(crypto.generateUniqueId().getBytes()),
+				new MailboxFolderId(crypto.generateUniqueId().getBytes()));
+		Group g = getContactGroup(c);
+		storeMessageReplaceLatest(txn, g.getId(), p);
+	}
+
+	/**
+	 * Sends an empty update message to the given contact. The empty update
+	 * indicates for the receiving contact that we no longer have a Mailbox that
+	 * they can use.
+	 */
+	private void sendEmptyProperties(Transaction txn, Contact c)
+			throws DbException {
+		Group g = getContactGroup(c);
+		storeMessageReplaceLatest(txn, g.getId(), null);
+	}
+
+	@Nullable
+	private MailboxPropertiesUpdate getProperties(Transaction txn,
+			Contact c, boolean local) throws DbException {
+		MailboxPropertiesUpdate p = null;
+		Group g = getContactGroup(c);
+		try {
+			LatestUpdate latest = findLatest(txn, g.getId(), local);
+			if (latest != null) {
+				BdfList body =
+						clientHelper.getMessageAsList(txn, latest.messageId);
+				p = parseProperties(body);
+			}
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+		return p;
+	}
+
+	private void storeMessageReplaceLatest(Transaction txn, GroupId g,
+			@Nullable MailboxPropertiesUpdate p) throws DbException {
+		try {
+			LatestUpdate latest = findLatest(txn, g, true);
+			long version = latest == null ? 1 : latest.version + 1;
+			Message m = clientHelper.createMessage(g, clock.currentTimeMillis(),
+					encodeProperties(version, p));
+			BdfDictionary meta = new BdfDictionary();
+			meta.put(MSG_KEY_VERSION, version);
+			meta.put(MSG_KEY_LOCAL, true);
+			clientHelper.addLocalMessage(txn, m, meta, true, false);
+			if (latest != null) {
+				db.removeMessage(txn, latest.messageId);
+			}
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
+	@Nullable
+	private LatestUpdate findLatest(Transaction txn, GroupId g, boolean local)
+			throws DbException, FormatException {
+		Map<MessageId, BdfDictionary> metadata =
+				clientHelper.getMessageMetadataAsDictionary(txn, g);
+		// We should have at most 1 local and 1 remote
+		if (metadata.size() > 2) {
+			throw new IllegalStateException();
+		}
+		for (Entry<MessageId, BdfDictionary> e : metadata.entrySet()) {
+			BdfDictionary meta = e.getValue();
+			if (meta.getBoolean(MSG_KEY_LOCAL) == local) {
+				return new LatestUpdate(e.getKey(),
+						meta.getLong(MSG_KEY_VERSION));
+			}
+		}
+		return null;
+	}
+
+	private BdfList encodeProperties(long version,
+			@Nullable MailboxPropertiesUpdate p) {
+		BdfDictionary dict = new BdfDictionary();
+		if (p != null) {
+			dict.put(PROP_KEY_ONION, p.getOnion());
+			dict.put(PROP_KEY_AUTHTOKEN, p.getAuthToken().getBytes());
+			dict.put(PROP_KEY_INBOXID, p.getInboxId().getBytes());
+			dict.put(PROP_KEY_OUTBOXID, p.getOutboxId().getBytes());
+		}
+		return BdfList.of(version, dict);
+	}
+
+	@Nullable
+	private MailboxPropertiesUpdate parseProperties(BdfList body)
+			throws FormatException {
+		BdfDictionary dict = body.getDictionary(1);
+		return clientHelper.parseAndValidateMailboxPropertiesUpdate(dict);
+	}
+
+	private Group getContactGroup(Contact c) {
+		return contactGroupFactory.createContactGroup(CLIENT_ID, MAJOR_VERSION,
+				c);
+	}
+
+	private static class LatestUpdate {
+
+		private final MessageId messageId;
+		private final long version;
+
+		private LatestUpdate(MessageId messageId, long version) {
+			this.messageId = messageId;
+			this.version = version;
+		}
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/mailbox/MailboxPropertyValidator.java

@@ -0,0 +1,49 @@
+package org.briarproject.bramble.mailbox;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.client.BdfMessageContext;
+import org.briarproject.bramble.api.client.BdfMessageValidator;
+import org.briarproject.bramble.api.client.ClientHelper;
+import org.briarproject.bramble.api.data.BdfDictionary;
+import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.data.MetadataEncoder;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.Group;
+import org.briarproject.bramble.api.sync.InvalidMessageException;
+import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.system.Clock;
+
+import javax.annotation.concurrent.Immutable;
+
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.MSG_KEY_LOCAL;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.MSG_KEY_VERSION;
+import static org.briarproject.bramble.util.ValidationUtils.checkSize;
+
+@Immutable
+@NotNullByDefault
+class MailboxPropertyValidator extends BdfMessageValidator {
+
+	MailboxPropertyValidator(ClientHelper clientHelper,
+			MetadataEncoder metadataEncoder, Clock clock) {
+		super(clientHelper, metadataEncoder, clock);
+	}
+
+	@Override
+	protected BdfMessageContext validateMessage(Message m, Group g,
+			BdfList body) throws InvalidMessageException, FormatException {
+		// Version, properties
+		checkSize(body, 2);
+		// Version
+		long version = body.getLong(0);
+		if (version < 0) throw new FormatException();
+		// Properties
+		BdfDictionary dictionary = body.getDictionary(1);
+		clientHelper.parseAndValidateMailboxPropertiesUpdate(dictionary);
+		// Return the metadata
+		BdfDictionary meta = new BdfDictionary();
+		meta.put(MSG_KEY_VERSION, version);
+		meta.put(MSG_KEY_LOCAL, false);
+		return new BdfMessageContext(meta);
+	}
+
+}

bramble-core/src/main/java/org/briarproject/bramble/mailbox/MailboxSettingsManagerImpl.java

@@ -12,6 +12,9 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.settings.Settings;
 import org.briarproject.bramble.api.settings.SettingsManager;
 
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
@@ -32,12 +35,18 @@ class MailboxSettingsManagerImpl implements MailboxSettingsManager {
 	static final String SETTINGS_UPLOADS_NAMESPACE = "mailbox-uploads";
 
 	private final SettingsManager settingsManager;
+	private final List<MailboxHook> hooks = new CopyOnWriteArrayList<>();
 
 	@Inject
 	MailboxSettingsManagerImpl(SettingsManager settingsManager) {
 		this.settingsManager = settingsManager;
 	}
 
+	@Override
+	public void registerMailboxHook(MailboxHook hook) {
+		hooks.add(hook);
+	}
+
 	@Override
 	public MailboxProperties getOwnMailboxProperties(Transaction txn)
 			throws DbException {
@@ -60,6 +69,9 @@ class MailboxSettingsManagerImpl implements MailboxSettingsManager {
 		s.put(SETTINGS_KEY_ONION, p.getBaseUrl());
 		s.put(SETTINGS_KEY_TOKEN, p.getAuthToken().toString());
 		settingsManager.mergeSettings(txn, s, SETTINGS_NAMESPACE);
+		for (MailboxHook hook : hooks) {
+			hook.mailboxPaired(txn, p.getOnion());
+		}
 	}
 
 	@Override

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

@@ -682,8 +682,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		byte[] localSeed = alice ? aliceSeed : bobSeed;
 		byte[] remoteSeed = alice ? bobSeed : aliceSeed;
 		String blob = torRendezvousCrypto.getPrivateKeyBlob(localSeed);
-		String localOnion = torRendezvousCrypto.getOnionAddress(localSeed);
+		String localOnion = torRendezvousCrypto.getOnion(localSeed);
-		String remoteOnion = torRendezvousCrypto.getOnionAddress(remoteSeed);
+		String remoteOnion = torRendezvousCrypto.getOnion(remoteSeed);
 		TransportProperties remoteProperties = new TransportProperties();
 		remoteProperties.put(PROP_ONION_V3, remoteOnion);
 		try {

bramble-core/src/main/java/org/briarproject/bramble/plugin/tor/TorRendezvousCrypto.java

@@ -4,7 +4,7 @@ interface TorRendezvousCrypto {
 
 	static final int SEED_BYTES = 32;
 
-	String getOnionAddress(byte[] seed);
+	String getOnion(byte[] seed);
 
 	String getPrivateKeyBlob(byte[] seed);
 }

bramble-core/src/main/java/org/briarproject/bramble/plugin/tor/TorRendezvousCryptoImpl.java

@@ -21,9 +21,9 @@ class TorRendezvousCryptoImpl implements TorRendezvousCrypto {
 	}
 
 	@Override
-	public String getOnionAddress(byte[] seed) {
+	public String getOnion(byte[] seed) {
 		EdDSAPrivateKeySpec spec = new EdDSAPrivateKeySpec(seed, CURVE_SPEC);
-		return crypto.encodeOnionAddress(spec.getA().toByteArray());
+		return crypto.encodeOnion(spec.getA().toByteArray());
 	}
 
 	@Override

bramble-core/src/test/java/org/briarproject/bramble/client/ClientHelperImplTest.java

@@ -1,6 +1,7 @@
 package org.briarproject.bramble.client;
 
 import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.UniqueId;
 import org.briarproject.bramble.api.client.ClientHelper;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.KeyParser;
@@ -20,13 +21,15 @@ import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorFactory;
+import org.briarproject.bramble.api.mailbox.MailboxAuthToken;
+import org.briarproject.bramble.api.mailbox.MailboxFolderId;
+import org.briarproject.bramble.api.mailbox.MailboxPropertiesUpdate;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageFactory;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.test.BrambleMockTestCase;
 import org.briarproject.bramble.test.DbExpectations;
-import org.briarproject.bramble.util.StringUtils;
 import org.jmock.Expectations;
 import org.junit.Test;
 
@@ -41,15 +44,22 @@ import java.util.Random;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_SIGNATURE_LENGTH;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.PROP_KEY_AUTHTOKEN;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.PROP_KEY_INBOXID;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.PROP_KEY_ONION;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.PROP_KEY_OUTBOXID;
 import static org.briarproject.bramble.test.TestUtils.getAuthor;
 import static org.briarproject.bramble.test.TestUtils.getMessage;
 import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
 import static org.briarproject.bramble.test.TestUtils.getRandomId;
 import static org.briarproject.bramble.test.TestUtils.getSignaturePrivateKey;
 import static org.briarproject.bramble.test.TestUtils.getSignaturePublicKey;
+import static org.briarproject.bramble.test.TestUtils.mailboxPropertiesUpdateEqual;
 import static org.briarproject.bramble.util.StringUtils.getRandomString;
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
 public class ClientHelperImplTest extends BrambleMockTestCase {
@@ -78,13 +88,35 @@ public class ClientHelperImplTest extends BrambleMockTestCase {
 	private final long timestamp = message.getTimestamp();
 	private final Metadata metadata = new Metadata();
 	private final BdfList list = BdfList.of("Sign this!", getRandomBytes(42));
-	private final String label = StringUtils.getRandomString(5);
+	private final String label = getRandomString(5);
 	private final Author author = getAuthor();
 
 	private final ClientHelper clientHelper = new ClientHelperImpl(db,
 			messageFactory, bdfReaderFactory, bdfWriterFactory, metadataParser,
 			metadataEncoder, cryptoComponent, authorFactory);
 
+	private final MailboxPropertiesUpdate validMailboxPropsUpdate;
+
+	public ClientHelperImplTest() {
+		validMailboxPropsUpdate = new MailboxPropertiesUpdate(
+				"pg6mmjiyjmcrsslvykfwnntlaru7p5svn6y2ymmju6nubxndf4pscryd",
+				new MailboxAuthToken(getRandomId()),
+				new MailboxFolderId(getRandomId()),
+				new MailboxFolderId(getRandomId()));
+	}
+
+	private BdfDictionary getValidMailboxPropsUpdateDict() {
+		BdfDictionary dict = new BdfDictionary();
+		dict.put(PROP_KEY_ONION, validMailboxPropsUpdate.getOnion());
+		dict.put(PROP_KEY_AUTHTOKEN, validMailboxPropsUpdate.getAuthToken()
+				.getBytes());
+		dict.put(PROP_KEY_INBOXID, validMailboxPropsUpdate.getInboxId()
+				.getBytes());
+		dict.put(PROP_KEY_OUTBOXID, validMailboxPropsUpdate.getOutboxId()
+				.getBytes());
+		return dict;
+	}
+
 	@Test
 	public void testAddLocalMessage() throws Exception {
 		boolean shared = new Random().nextBoolean();
@@ -513,4 +545,95 @@ public class ClientHelperImplTest extends BrambleMockTestCase {
 			will(returnValue(eof));
 		}});
 	}
+
+	@Test
+	public void testParseEmptyMailboxPropsUpdate() throws Exception {
+		BdfDictionary emptyPropsDict = new BdfDictionary();
+		MailboxPropertiesUpdate parsedProps = clientHelper
+				.parseAndValidateMailboxPropertiesUpdate(emptyPropsDict);
+		assertNull(parsedProps);
+	}
+
+	@Test
+	public void testParseValidMailboxPropsUpdate() throws Exception {
+		MailboxPropertiesUpdate parsedProps = clientHelper
+				.parseAndValidateMailboxPropertiesUpdate(
+						getValidMailboxPropsUpdateDict());
+		assertTrue(mailboxPropertiesUpdateEqual(validMailboxPropsUpdate,
+				parsedProps));
+	}
+
+	@Test(expected = FormatException.class)
+	public void testRejectsMailboxPropsUpdateOnionNotDecodable()
+			throws Exception {
+		BdfDictionary propsDict = getValidMailboxPropsUpdateDict();
+		String badOnion = "!" + propsDict.getString(PROP_KEY_ONION)
+				.substring(1);
+		propsDict.put(PROP_KEY_ONION, badOnion);
+		clientHelper.parseAndValidateMailboxPropertiesUpdate(propsDict);
+	}
+
+	@Test(expected = FormatException.class)
+	public void testRejectsMailboxPropsUpdateOnionWrongLength()
+			throws Exception {
+		BdfDictionary propsDict = getValidMailboxPropsUpdateDict();
+		String tooLongOnion = propsDict.getString(PROP_KEY_ONION) + "!";
+		propsDict.put(PROP_KEY_ONION, tooLongOnion);
+		clientHelper.parseAndValidateMailboxPropertiesUpdate(propsDict);
+	}
+
+	@Test(expected = FormatException.class)
+	public void testRejectsMailboxPropsUpdateInboxIdWrongLength()
+			throws Exception {
+		BdfDictionary propsDict = getValidMailboxPropsUpdateDict();
+		propsDict.put(PROP_KEY_INBOXID, getRandomBytes(UniqueId.LENGTH + 1));
+		clientHelper.parseAndValidateMailboxPropertiesUpdate(propsDict);
+	}
+
+	@Test(expected = FormatException.class)
+	public void testRejectsMailboxPropsUpdateOutboxIdWrongLength()
+			throws Exception {
+		BdfDictionary propsDict = getValidMailboxPropsUpdateDict();
+		propsDict.put(PROP_KEY_OUTBOXID, getRandomBytes(UniqueId.LENGTH + 1));
+		clientHelper.parseAndValidateMailboxPropertiesUpdate(propsDict);
+	}
+
+	@Test(expected = FormatException.class)
+	public void testRejectsMailboxPropsUpdateAuthTokenWrongLength()
+			throws Exception {
+		BdfDictionary propsDict = getValidMailboxPropsUpdateDict();
+		propsDict.put(PROP_KEY_AUTHTOKEN, getRandomBytes(UniqueId.LENGTH + 1));
+		clientHelper.parseAndValidateMailboxPropertiesUpdate(propsDict);
+	}
+
+	@Test(expected = FormatException.class)
+	public void testRejectsMailboxPropsUpdateMissingOnion() throws Exception {
+		BdfDictionary propsDict = getValidMailboxPropsUpdateDict();
+		propsDict.remove(PROP_KEY_ONION);
+		clientHelper.parseAndValidateMailboxPropertiesUpdate(propsDict);
+	}
+
+	@Test(expected = FormatException.class)
+	public void testRejectsMailboxPropsUpdateMissingAuthToken()
+			throws Exception {
+		BdfDictionary propsDict = getValidMailboxPropsUpdateDict();
+		propsDict.remove(PROP_KEY_AUTHTOKEN);
+		clientHelper.parseAndValidateMailboxPropertiesUpdate(propsDict);
+	}
+
+	@Test(expected = FormatException.class)
+	public void testRejectsMailboxPropsUpdateMissingInboxId() throws Exception {
+		BdfDictionary propsDict = getValidMailboxPropsUpdateDict();
+		propsDict.remove(PROP_KEY_INBOXID);
+		clientHelper.parseAndValidateMailboxPropertiesUpdate(propsDict);
+	}
+
+	@Test(expected = FormatException.class)
+	public void testRejectsMailboxPropsUpdateMissingOutboxId()
+			throws Exception {
+		BdfDictionary propsDict = getValidMailboxPropsUpdateDict();
+		propsDict.remove(PROP_KEY_OUTBOXID);
+		clientHelper.parseAndValidateMailboxPropertiesUpdate(propsDict);
+	}
+
 }

bramble-core/src/test/java/org/briarproject/bramble/mailbox/MailboxPairingTaskImplTest.java

@@ -87,7 +87,7 @@ public class MailboxPairingTaskImplTest extends BrambleMockTestCase {
 	@Test
 	public void testSuccessfulPairing() throws Exception {
 		context.checking(new Expectations() {{
-			oneOf(crypto).encodeOnionAddress(onionBytes);
+			oneOf(crypto).encodeOnion(onionBytes);
 			will(returnValue(onion));
 			oneOf(api).setup(with(matches(setupProperties)));
 			will(returnValue(ownerToken));
@@ -141,7 +141,7 @@ public class MailboxPairingTaskImplTest extends BrambleMockTestCase {
 	private void testApiException(Exception e,
 			Class<? extends MailboxPairingState> s) throws Exception {
 		context.checking(new Expectations() {{
-			oneOf(crypto).encodeOnionAddress(onionBytes);
+			oneOf(crypto).encodeOnion(onionBytes);
 			will(returnValue(onion));
 			oneOf(api).setup(with(matches(setupProperties)));
 			will(throwException(e));
@@ -155,7 +155,7 @@ public class MailboxPairingTaskImplTest extends BrambleMockTestCase {
 	@Test
 	public void testDbException() throws Exception {
 		context.checking(new Expectations() {{
-			oneOf(crypto).encodeOnionAddress(onionBytes);
+			oneOf(crypto).encodeOnion(onionBytes);
 			will(returnValue(onion));
 			oneOf(api).setup(with(matches(setupProperties)));
 			will(returnValue(ownerToken));

bramble-core/src/test/java/org/briarproject/bramble/mailbox/MailboxPropertyManagerImplTest.java

@@ -0,0 +1,671 @@
+package org.briarproject.bramble.mailbox;
+
+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.ContactManager;
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+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.MetadataParser;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.Metadata;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.mailbox.MailboxAuthToken;
+import org.briarproject.bramble.api.mailbox.MailboxFolderId;
+import org.briarproject.bramble.api.mailbox.MailboxProperties;
+import org.briarproject.bramble.api.mailbox.MailboxPropertiesUpdate;
+import org.briarproject.bramble.api.mailbox.MailboxSettingsManager;
+import org.briarproject.bramble.api.sync.Group;
+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.bramble.test.BrambleMockTestCase;
+import org.jmock.Expectations;
+import org.junit.Test;
+
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import static java.util.Collections.singletonList;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.CLIENT_ID;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.MAJOR_VERSION;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.MSG_KEY_LOCAL;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.MSG_KEY_VERSION;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.PROP_KEY_AUTHTOKEN;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.PROP_KEY_INBOXID;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.PROP_KEY_ONION;
+import static org.briarproject.bramble.api.mailbox.MailboxPropertyManager.PROP_KEY_OUTBOXID;
+import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
+import static org.briarproject.bramble.api.sync.validation.IncomingMessageHook.DeliveryAction.ACCEPT_DO_NOT_SHARE;
+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.test.TestUtils.mailboxPropertiesUpdateEqual;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+public class MailboxPropertyManagerImplTest extends BrambleMockTestCase {
+
+	private final DatabaseComponent db = context.mock(DatabaseComponent.class);
+	private final ClientHelper clientHelper = context.mock(ClientHelper.class);
+	private final ClientVersioningManager clientVersioningManager =
+			context.mock(ClientVersioningManager.class);
+	private final MetadataParser metadataParser =
+			context.mock(MetadataParser.class);
+	private final ContactGroupFactory contactGroupFactory =
+			context.mock(ContactGroupFactory.class);
+	private final Clock clock = context.mock(Clock.class);
+	private final CryptoComponent crypto = context.mock(CryptoComponent.class);
+	private final MailboxSettingsManager mailboxSettingsManager =
+			context.mock(MailboxSettingsManager.class);
+	private final ContactManager contactManager =
+			context.mock(ContactManager.class);
+
+	private final Group localGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+	private final BdfDictionary propsDict;
+	private final BdfDictionary emptyPropsDict = new BdfDictionary();
+	private final MailboxPropertiesUpdate props;
+	private final MailboxProperties ownProps;
+
+	public MailboxPropertyManagerImplTest() {
+		ownProps = new MailboxProperties("http://bar.onion",
+				new MailboxAuthToken(getRandomId()), true);
+		props = new MailboxPropertiesUpdate(ownProps.getOnion(),
+				new MailboxAuthToken(getRandomId()),
+				new MailboxFolderId(getRandomId()),
+				new MailboxFolderId(getRandomId()));
+		propsDict = new BdfDictionary();
+		propsDict.put(PROP_KEY_ONION, props.getOnion());
+		propsDict.put(PROP_KEY_AUTHTOKEN, props.getAuthToken().getBytes());
+		propsDict.put(PROP_KEY_INBOXID, props.getInboxId().getBytes());
+		propsDict.put(PROP_KEY_OUTBOXID, props.getOutboxId().getBytes());
+	}
+
+	private MailboxPropertyManagerImpl createInstance() {
+		context.checking(new Expectations() {{
+			oneOf(contactGroupFactory).createLocalGroup(CLIENT_ID,
+					MAJOR_VERSION);
+			will(returnValue(localGroup));
+		}});
+		return new MailboxPropertyManagerImpl(db, clientHelper,
+				clientVersioningManager, metadataParser, contactGroupFactory,
+				clock, mailboxSettingsManager, contactManager, crypto);
+	}
+
+	@Test
+	public void testCreatesGroupsAtUnpairedStartup() throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact();
+		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+
+		context.checking(new Expectations() {{
+			oneOf(db).containsGroup(txn, localGroup.getId());
+			will(returnValue(false));
+			oneOf(db).addGroup(txn, localGroup);
+			oneOf(db).getContacts(txn);
+			will(returnValue(singletonList(contact)));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(db).addGroup(txn, contactGroup);
+			oneOf(clientVersioningManager).getClientVisibility(txn,
+					contact.getId(), CLIENT_ID, MAJOR_VERSION);
+			will(returnValue(SHARED));
+			oneOf(db).setGroupVisibility(txn, contact.getId(),
+					contactGroup.getId(), SHARED);
+			oneOf(mailboxSettingsManager).getOwnMailboxProperties(txn);
+			will(returnValue(null));
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		t.onDatabaseOpened(txn);
+	}
+
+	@Test
+	public void testCreatesGroupsAndCreatesAndSendsAtPairedStartup()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact();
+		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+		Map<MessageId, BdfDictionary> messageMetadata = new LinkedHashMap<>();
+
+		context.checking(new Expectations() {{
+			oneOf(db).containsGroup(txn, localGroup.getId());
+			will(returnValue(false));
+			oneOf(db).addGroup(txn, localGroup);
+			oneOf(db).getContacts(txn);
+			will(returnValue(singletonList(contact)));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(db).addGroup(txn, contactGroup);
+			oneOf(clientVersioningManager).getClientVisibility(txn,
+					contact.getId(), CLIENT_ID, MAJOR_VERSION);
+			will(returnValue(SHARED));
+			oneOf(db).setGroupVisibility(txn, contact.getId(),
+					contactGroup.getId(), SHARED);
+			oneOf(mailboxSettingsManager).getOwnMailboxProperties(txn);
+			will(returnValue(ownProps));
+			oneOf(crypto).generateUniqueId();
+			will(returnValue(props.getAuthToken()));
+			oneOf(crypto).generateUniqueId();
+			will(returnValue(props.getInboxId()));
+			oneOf(crypto).generateUniqueId();
+			will(returnValue(props.getOutboxId()));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(messageMetadata));
+			expectStoreMessage(txn, contactGroup.getId(), propsDict, 1, true);
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		t.onDatabaseOpened(txn);
+	}
+
+	@Test
+	public void testDoesNotCreateGroupsAtStartupIfAlreadyCreated()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+
+		context.checking(new Expectations() {{
+			oneOf(db).containsGroup(txn, localGroup.getId());
+			will(returnValue(true));
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		t.onDatabaseOpened(txn);
+	}
+
+	@Test
+	public void testCreatesContactGroupWhenAddingContactUnpaired()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact();
+		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+
+		context.checking(new Expectations() {{
+			// Create the group and share it with the contact
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(db).addGroup(txn, contactGroup);
+			oneOf(clientVersioningManager).getClientVisibility(txn,
+					contact.getId(), CLIENT_ID, MAJOR_VERSION);
+			will(returnValue(SHARED));
+			oneOf(db).setGroupVisibility(txn, contact.getId(),
+					contactGroup.getId(), SHARED);
+			oneOf(mailboxSettingsManager).getOwnMailboxProperties(txn);
+			will(returnValue(null));
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		t.addingContact(txn, contact);
+	}
+
+	@Test
+	public void testCreatesContactGroupAndCreatesAndSendsWhenAddingContactPaired()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact();
+		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+		Map<MessageId, BdfDictionary> messageMetadata = new LinkedHashMap<>();
+
+		context.checking(new Expectations() {{
+			// Create the group and share it with the contact
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(db).addGroup(txn, contactGroup);
+			oneOf(clientVersioningManager).getClientVisibility(txn,
+					contact.getId(), CLIENT_ID, MAJOR_VERSION);
+			will(returnValue(SHARED));
+			oneOf(db).setGroupVisibility(txn, contact.getId(),
+					contactGroup.getId(), SHARED);
+			oneOf(mailboxSettingsManager).getOwnMailboxProperties(txn);
+			will(returnValue(ownProps));
+			oneOf(crypto).generateUniqueId();
+			will(returnValue(props.getAuthToken()));
+			oneOf(crypto).generateUniqueId();
+			will(returnValue(props.getInboxId()));
+			oneOf(crypto).generateUniqueId();
+			will(returnValue(props.getOutboxId()));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(messageMetadata));
+			expectStoreMessage(txn, contactGroup.getId(), propsDict, 1, true);
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		t.addingContact(txn, contact);
+	}
+
+	@Test
+	public void testRemovesGroupWhenRemovingContact() throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact();
+		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+
+		context.checking(new Expectations() {{
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(db).removeGroup(txn, contactGroup);
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		t.removingContact(txn, contact);
+	}
+
+	@Test
+	public void testDoesNotDeleteAnythingWhenFirstUpdateIsDelivered()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		GroupId contactGroupId = new GroupId(getRandomId());
+		Message message = getMessage(contactGroupId);
+		Metadata meta = new Metadata();
+		BdfDictionary metaDictionary = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, false)
+		);
+		Map<MessageId, BdfDictionary> messageMetadata = new LinkedHashMap<>();
+		// A local update should be ignored
+		MessageId localUpdateId = new MessageId(getRandomId());
+		messageMetadata.put(localUpdateId, BdfDictionary.of(
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, true)
+		));
+
+		context.checking(new Expectations() {{
+			oneOf(metadataParser).parse(meta);
+			will(returnValue(metaDictionary));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroupId);
+			will(returnValue(messageMetadata));
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		assertEquals(ACCEPT_DO_NOT_SHARE,
+				t.incomingMessage(txn, message, meta));
+	}
+
+	@Test
+	public void testDeletesOlderUpdateWhenUpdateIsDelivered()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		GroupId contactGroupId = new GroupId(getRandomId());
+		Message message = getMessage(contactGroupId);
+		Metadata meta = new Metadata();
+		BdfDictionary metaDictionary = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_VERSION, 2),
+				new BdfEntry(MSG_KEY_LOCAL, false)
+		);
+		Map<MessageId, BdfDictionary> messageMetadata = new LinkedHashMap<>();
+		// This older version should be deleted
+		MessageId updateId = new MessageId(getRandomId());
+		messageMetadata.put(updateId, BdfDictionary.of(
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, false)
+		));
+		// A local update should be ignored
+		MessageId localUpdateId = new MessageId(getRandomId());
+		messageMetadata.put(localUpdateId, BdfDictionary.of(
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, true)
+		));
+
+		context.checking(new Expectations() {{
+			oneOf(metadataParser).parse(meta);
+			will(returnValue(metaDictionary));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroupId);
+			will(returnValue(messageMetadata));
+			oneOf(db).deleteMessage(txn, updateId);
+			oneOf(db).deleteMessageMetadata(txn, updateId);
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		assertEquals(ACCEPT_DO_NOT_SHARE,
+				t.incomingMessage(txn, message, meta));
+	}
+
+	@Test
+	public void testDeletesObsoleteUpdateWhenDelivered() throws Exception {
+		Transaction txn = new Transaction(null, false);
+		GroupId contactGroupId = new GroupId(getRandomId());
+		Message message = getMessage(contactGroupId);
+		Metadata meta = new Metadata();
+		BdfDictionary metaDictionary = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_VERSION, 3),
+				new BdfEntry(MSG_KEY_LOCAL, false)
+		);
+		Map<MessageId, BdfDictionary> messageMetadata = new LinkedHashMap<>();
+		// This newer version should not be deleted
+		MessageId updateId = new MessageId(getRandomId());
+		messageMetadata.put(updateId, BdfDictionary.of(
+				new BdfEntry(MSG_KEY_VERSION, 4),
+				new BdfEntry(MSG_KEY_LOCAL, false)
+		));
+
+		context.checking(new Expectations() {{
+			oneOf(metadataParser).parse(meta);
+			will(returnValue(metaDictionary));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroupId);
+			will(returnValue(messageMetadata));
+			oneOf(db).deleteMessage(txn, message.getId());
+			oneOf(db).deleteMessageMetadata(txn, message.getId());
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		assertEquals(ACCEPT_DO_NOT_SHARE,
+				t.incomingMessage(txn, message, meta));
+	}
+
+	@Test
+	public void testCreatesAndStoresLocalPropertiesWithNewVersionOnPairing()
+			throws Exception {
+		Contact contact = getContact();
+		List<Contact> contacts = singletonList(contact);
+		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+
+		Transaction txn = new Transaction(null, false);
+		Map<MessageId, BdfDictionary> messageMetadata = new LinkedHashMap<>();
+		MessageId latestId = new MessageId(getRandomId());
+		messageMetadata.put(latestId, BdfDictionary.of(
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, true)
+		));
+		// Some remote props, ignored
+		messageMetadata.put(new MessageId(getRandomId()), BdfDictionary.of(
+				new BdfEntry(MSG_KEY_VERSION, 3),
+				new BdfEntry(MSG_KEY_LOCAL, false)
+		));
+
+		context.checking(new Expectations() {{
+			oneOf(contactManager).getContacts();
+			will(returnValue(contacts));
+			oneOf(crypto).generateUniqueId();
+			will(returnValue(props.getAuthToken()));
+			oneOf(crypto).generateUniqueId();
+			will(returnValue(props.getInboxId()));
+			oneOf(crypto).generateUniqueId();
+			will(returnValue(props.getOutboxId()));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(messageMetadata));
+			expectStoreMessage(txn, contactGroup.getId(), propsDict, 2, true);
+			oneOf(db).removeMessage(txn, latestId);
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		t.mailboxPaired(txn, ownProps.getOnion());
+	}
+
+	@Test
+	public void testStoresEmptyLocalPropertiesWithNewVersionOnUnpairing()
+			throws Exception {
+		Contact contact = getContact();
+		List<Contact> contacts = singletonList(contact);
+		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+
+		Transaction txn = new Transaction(null, false);
+		Map<MessageId, BdfDictionary> messageMetadata = new LinkedHashMap<>();
+		MessageId latestId = new MessageId(getRandomId());
+		messageMetadata.put(latestId, BdfDictionary.of(
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, true)
+		));
+		// Some remote props, ignored
+		messageMetadata.put(new MessageId(getRandomId()), BdfDictionary.of(
+				new BdfEntry(MSG_KEY_VERSION, 3),
+				new BdfEntry(MSG_KEY_LOCAL, false)
+		));
+
+		context.checking(new Expectations() {{
+			oneOf(contactManager).getContacts();
+			will(returnValue(contacts));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(messageMetadata));
+			expectStoreMessage(txn, contactGroup.getId(), emptyPropsDict,
+					2, true);
+			oneOf(db).removeMessage(txn, latestId);
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		t.mailboxUnpaired(txn);
+	}
+
+	@Test
+	public void testGetRemoteProperties()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact();
+		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+		BdfDictionary metaDictionary = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, false)
+		);
+		Map<MessageId, BdfDictionary> messageMetadata = new LinkedHashMap<>();
+		MessageId fooUpdateId = new MessageId(getRandomId());
+		messageMetadata.put(fooUpdateId, metaDictionary);
+		BdfList fooUpdate = BdfList.of(1, propsDict);
+
+		context.checking(new Expectations() {{
+			oneOf(db).getContact(txn, contact.getId());
+			will(returnValue(contact));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(messageMetadata));
+			oneOf(clientHelper).getMessageAsList(txn, fooUpdateId);
+			will(returnValue(fooUpdate));
+			oneOf(clientHelper).parseAndValidateMailboxPropertiesUpdate(
+					propsDict);
+			will(returnValue(props));
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		MailboxPropertiesUpdate remote =
+				t.getRemoteProperties(txn, contact.getId());
+		assertTrue(mailboxPropertiesUpdateEqual(remote, props));
+	}
+
+	@Test
+	public void testGetRemotePropertiesReturnsNullBecauseNoUpdate()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact();
+		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+		Map<MessageId, BdfDictionary> emptyMessageMetadata =
+				new LinkedHashMap<>();
+
+		context.checking(new Expectations() {{
+			oneOf(db).getContact(txn, contact.getId());
+			will(returnValue(contact));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(emptyMessageMetadata));
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		assertNull(t.getRemoteProperties(txn, contact.getId()));
+	}
+
+	@Test
+	public void testGetRemotePropertiesReturnsNullBecauseEmptyUpdate()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact();
+		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+		BdfDictionary metaDictionary = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, false)
+		);
+		Map<MessageId, BdfDictionary> messageMetadata = new LinkedHashMap<>();
+		MessageId fooUpdateId = new MessageId(getRandomId());
+		messageMetadata.put(fooUpdateId, metaDictionary);
+		BdfList fooUpdate = BdfList.of(1, emptyPropsDict);
+
+		context.checking(new Expectations() {{
+			oneOf(db).getContact(txn, contact.getId());
+			will(returnValue(contact));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(messageMetadata));
+			oneOf(clientHelper).getMessageAsList(txn, fooUpdateId);
+			will(returnValue(fooUpdate));
+			oneOf(clientHelper).parseAndValidateMailboxPropertiesUpdate(
+					emptyPropsDict);
+			will(returnValue(null));
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		assertNull(t.getRemoteProperties(txn, contact.getId()));
+	}
+
+	@Test
+	public void testGetLocalProperties()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact();
+		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+		BdfDictionary metaDictionary = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, true)
+		);
+		Map<MessageId, BdfDictionary> messageMetadata = new LinkedHashMap<>();
+		MessageId fooUpdateId = new MessageId(getRandomId());
+		messageMetadata.put(fooUpdateId, metaDictionary);
+		BdfList fooUpdate = BdfList.of(1, propsDict);
+
+		context.checking(new Expectations() {{
+			oneOf(db).getContact(txn, contact.getId());
+			will(returnValue(contact));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(messageMetadata));
+			oneOf(clientHelper).getMessageAsList(txn, fooUpdateId);
+			will(returnValue(fooUpdate));
+			oneOf(clientHelper).parseAndValidateMailboxPropertiesUpdate(
+					propsDict);
+			will(returnValue(props));
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		MailboxPropertiesUpdate local =
+				t.getLocalProperties(txn, contact.getId());
+		assertTrue(mailboxPropertiesUpdateEqual(local, props));
+	}
+
+	@Test
+	public void testGetLocalPropertiesReturnsNullBecauseNoUpdate()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact();
+		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+		Map<MessageId, BdfDictionary> emptyMessageMetadata =
+				new LinkedHashMap<>();
+
+		context.checking(new Expectations() {{
+			oneOf(db).getContact(txn, contact.getId());
+			will(returnValue(contact));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(emptyMessageMetadata));
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		assertNull(t.getLocalProperties(txn, contact.getId()));
+	}
+
+	@Test
+	public void testGetLocalPropertiesReturnsNullBecauseEmptyUpdate()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact();
+		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+		BdfDictionary metaDictionary = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, true)
+		);
+		Map<MessageId, BdfDictionary> messageMetadata = new LinkedHashMap<>();
+		MessageId fooUpdateId = new MessageId(getRandomId());
+		messageMetadata.put(fooUpdateId, metaDictionary);
+		BdfList fooUpdate = BdfList.of(1, emptyPropsDict);
+
+		context.checking(new Expectations() {{
+			oneOf(db).getContact(txn, contact.getId());
+			will(returnValue(contact));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(messageMetadata));
+			oneOf(clientHelper).getMessageAsList(txn, fooUpdateId);
+			will(returnValue(fooUpdate));
+			oneOf(clientHelper).parseAndValidateMailboxPropertiesUpdate(
+					emptyPropsDict);
+			will(returnValue(null));
+		}});
+
+		MailboxPropertyManagerImpl t = createInstance();
+		assertNull(t.getLocalProperties(txn, contact.getId()));
+	}
+
+	private void expectStoreMessage(Transaction txn, GroupId g,
+			BdfDictionary properties, long version, boolean local)
+			throws Exception {
+		BdfList body = BdfList.of(version, properties);
+		Message message = getMessage(g);
+		long timestamp = message.getTimestamp();
+		BdfDictionary meta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_VERSION, version),
+				new BdfEntry(MSG_KEY_LOCAL, local)
+		);
+
+		context.checking(new Expectations() {{
+			oneOf(clock).currentTimeMillis();
+			will(returnValue(timestamp));
+			oneOf(clientHelper).createMessage(g, timestamp, body);
+			will(returnValue(message));
+			oneOf(clientHelper).addLocalMessage(txn, message, meta, true,
+					false);
+		}});
+	}
+
+}

bramble-core/src/test/java/org/briarproject/bramble/mailbox/MailboxPropertyValidatorTest.java

@@ -0,0 +1,99 @@
+package org.briarproject.bramble.mailbox;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.client.ClientHelper;
+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.MetadataEncoder;
+import org.briarproject.bramble.api.mailbox.MailboxAuthToken;
+import org.briarproject.bramble.api.mailbox.MailboxFolderId;
+import org.briarproject.bramble.api.mailbox.MailboxPropertiesUpdate;
+import org.briarproject.bramble.api.mailbox.MailboxPropertyManager;
+import org.briarproject.bramble.api.sync.Group;
+import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.jmock.Expectations;
+import org.junit.Test;
+
+import java.io.IOException;
+
+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.junit.Assert.assertEquals;
+
+public class MailboxPropertyValidatorTest extends BrambleMockTestCase {
+
+	private final ClientHelper clientHelper = context.mock(ClientHelper.class);
+
+	private final BdfDictionary bdfDict;
+	private final MailboxPropertiesUpdate mailboxProps;
+	private final Group group;
+	private final Message message;
+	private final MailboxPropertyValidator mpv;
+
+	public MailboxPropertyValidatorTest() {
+		// Just dummies, clientHelper is mocked so our test is a bit shallow;
+		//  not testing
+		//  {@link ClientHelper#parseAndValidateMailboxPropertiesUpdate(BdfDictionary)}
+		bdfDict = BdfDictionary.of(new BdfEntry("foo", "bar"));
+		mailboxProps = new MailboxPropertiesUpdate("baz",
+				new MailboxAuthToken(getRandomId()),
+				new MailboxFolderId(getRandomId()),
+				new MailboxFolderId(getRandomId()));
+
+		group = getGroup(MailboxPropertyManager.CLIENT_ID,
+				MailboxPropertyManager.MAJOR_VERSION);
+		message = getMessage(group.getId());
+
+		MetadataEncoder metadataEncoder = context.mock(MetadataEncoder.class);
+		Clock clock = context.mock(Clock.class);
+		mpv = new MailboxPropertyValidator(clientHelper, metadataEncoder,
+				clock);
+	}
+
+	@Test
+	public void testValidateMessageBody() throws IOException {
+		BdfList body = BdfList.of(4, bdfDict);
+
+		context.checking(new Expectations() {{
+			oneOf(clientHelper).parseAndValidateMailboxPropertiesUpdate(
+					bdfDict);
+			will(returnValue(mailboxProps));
+		}});
+
+		BdfDictionary result =
+				mpv.validateMessage(message, group, body).getDictionary();
+		assertEquals(4, result.getLong("version").longValue());
+	}
+
+	@Test(expected = FormatException.class)
+	public void testValidateWrongVersionValue() throws IOException {
+		BdfList body = BdfList.of(-1, bdfDict);
+		mpv.validateMessage(message, group, body);
+	}
+
+	@Test(expected = FormatException.class)
+	public void testValidateWrongVersionType() throws IOException {
+		BdfList body = BdfList.of(bdfDict, bdfDict);
+		mpv.validateMessage(message, group, body);
+	}
+
+	@Test
+	public void testEmptyPropertiesReturnsNull() throws IOException {
+		BdfDictionary emptyBdfDict = new BdfDictionary();
+		BdfList body = BdfList.of(42, emptyBdfDict);
+
+		context.checking(new Expectations() {{
+			oneOf(clientHelper).parseAndValidateMailboxPropertiesUpdate(
+					emptyBdfDict);
+			will(returnValue(null));
+		}});
+
+		BdfDictionary result =
+				mpv.validateMessage(message, group, body).getDictionary();
+		assertEquals(42, result.getLong("version").longValue());
+	}
+}

briar-api/src/main/java/org/briarproject/briar/api/client/SessionId.java

@@ -16,9 +16,4 @@ public class SessionId extends UniqueId {
 	public SessionId(byte[] id) {
 		super(id);
 	}
-
-	@Override
-	public boolean equals(Object o) {
-		return o instanceof SessionId && super.equals(o);
-	}
 }

briar-core/src/main/java/org/briarproject/briar/test/TestDataCreatorImpl.java

@@ -299,7 +299,7 @@ public class TestDataCreatorImpl implements TestDataCreator {
 	private String getRandomTorAddress() {
 		byte[] pubkeyBytes =
 				crypto.generateSignatureKeyPair().getPublic().getEncoded();
-		return crypto.encodeOnionAddress(pubkeyBytes);
+		return crypto.encodeOnion(pubkeyBytes);
 	}
 
 	private void addAvatar(Contact c) throws DbException {