Remove local author from contacts.

briar-core/src/main/java/org/briarproject/briar/client/ConversationClientImpl.java

@@ -8,6 +8,8 @@ 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.Transaction;
+import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.MessageId;
@@ -23,12 +25,14 @@ public abstract class ConversationClientImpl extends BdfIncomingMessageHook
 		implements ConversationClient {
 
 	protected final MessageTracker messageTracker;
+	protected final IdentityManager identityManager;
 
 	protected ConversationClientImpl(DatabaseComponent db,
 			ClientHelper clientHelper, MetadataParser metadataParser,
-			MessageTracker messageTracker) {
+			MessageTracker messageTracker, IdentityManager identityManager) {
 		super(db, clientHelper, metadataParser);
 		this.messageTracker = messageTracker;
+		this.identityManager = identityManager;
 	}
 
 	/**
@@ -40,11 +44,16 @@ public abstract class ConversationClientImpl extends BdfIncomingMessageHook
 		messageTracker.initializeGroupCount(txn, g);
 	}
 
+	protected AuthorId getLocalAuthorId(Transaction txn) throws DbException {
+		return identityManager.getLocalAuthor(txn).getId();
+	}
+
 	@Override
 	public GroupCount getGroupCount(Transaction txn, ContactId contactId)
 			throws DbException {
 		Contact contact = db.getContact(txn, contactId);
-		GroupId groupId = getContactGroup(contact).getId();
+		AuthorId local = getLocalAuthorId(txn);
+		GroupId groupId = getContactGroup(contact, local).getId();
 		return messageTracker.getGroupCount(txn, groupId);
 	}
 

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

@@ -148,8 +148,7 @@ abstract class AbstractProtocolEngine<S extends Session>
 	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);
+		Contact c = contactManager.getContact(txn, sender);
 		AuthorInfo otherAuthorInfo =
 				contactManager.getAuthorInfo(txn, otherAuthor.getId());
 		IntroductionResponse response =

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

@@ -249,9 +249,7 @@ class IntroduceeProtocolEngine
 				.trackMessage(txn, m.getGroupId(), m.getTimestamp(), false);
 
 		// Broadcast IntroductionRequestReceivedEvent
-		LocalAuthor localAuthor = identityManager.getLocalAuthor(txn);
-		Contact c = contactManager.getContact(txn, s.getIntroducer().getId(),
-				localAuthor.getId());
+		Contact c = contactManager.getContact(txn, s.getIntroducer().getId());
 		AuthorInfo authorInfo =
 				contactManager.getAuthorInfo(txn, m.getAuthor().getId());
 		IntroductionRequest request = new IntroductionRequest(m.getMessageId(),
@@ -432,14 +430,13 @@ class IntroduceeProtocolEngine
 
 		Map<TransportId, TransportKeySetId> keys = null;
 		try {
-			contactManager.addContact(txn, s.getRemote().author,
-					localAuthor.getId(), false);
+			contactManager.addContact(txn, s.getRemote().author, false);
 
 			// Only add transport properties and keys when the contact was added
 			// This will be changed once we have a way to reset state for peers
 			// that were contacts already at some point in the past.
 			Contact c = contactManager.getContact(txn,
-					s.getRemote().author.getId(), localAuthor.getId());
+					s.getRemote().author.getId());
 
 			// add the keys to the new contact
 			//noinspection ConstantConditions

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

@@ -18,7 +18,6 @@ import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.identity.AuthorInfo;
 import org.briarproject.bramble.api.identity.IdentityManager;
-import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.Client;
 import org.briarproject.bramble.api.sync.Group;
@@ -79,7 +78,6 @@ class IntroductionManagerImpl extends ConversationClientImpl
 	private final IntroducerProtocolEngine introducerEngine;
 	private final IntroduceeProtocolEngine introduceeEngine;
 	private final IntroductionCrypto crypto;
-	private final IdentityManager identityManager;
 
 	private final Group localGroup;
 
@@ -90,6 +88,7 @@ class IntroductionManagerImpl extends ConversationClientImpl
 			ClientVersioningManager clientVersioningManager,
 			MetadataParser metadataParser,
 			MessageTracker messageTracker,
+			IdentityManager identityManager,
 			ContactGroupFactory contactGroupFactory,
 			ContactManager contactManager,
 			MessageParser messageParser,
@@ -97,9 +96,9 @@ class IntroductionManagerImpl extends ConversationClientImpl
 			SessionParser sessionParser,
 			IntroducerProtocolEngine introducerEngine,
 			IntroduceeProtocolEngine introduceeEngine,
-			IntroductionCrypto crypto,
-			IdentityManager identityManager) {
-		super(db, clientHelper, metadataParser, messageTracker);
+			IntroductionCrypto crypto) {
+		super(db, clientHelper, metadataParser, messageTracker,
+				identityManager);
 		this.clientVersioningManager = clientVersioningManager;
 		this.contactGroupFactory = contactGroupFactory;
 		this.contactManager = contactManager;
@@ -109,7 +108,6 @@ class IntroductionManagerImpl extends ConversationClientImpl
 		this.introducerEngine = introducerEngine;
 		this.introduceeEngine = introduceeEngine;
 		this.crypto = crypto;
-		this.identityManager = identityManager;
 		this.localGroup =
 				contactGroupFactory.createLocalGroup(CLIENT_ID, MAJOR_VERSION);
 	}
@@ -126,7 +124,7 @@ class IntroductionManagerImpl extends ConversationClientImpl
 	@Override
 	public void addingContact(Transaction txn, Contact c) throws DbException {
 		// Create a group to share with the contact
-		Group g = getContactGroup(c);
+		Group g = getContactGroup(c, getLocalAuthorId(txn));
 		db.addGroup(txn, g);
 		// Apply the client's visibility to the contact group
 		Visibility client = clientVersioningManager.getClientVisibility(txn,
@@ -148,21 +146,21 @@ class IntroductionManagerImpl extends ConversationClientImpl
 		abortOrRemoveSessionWithIntroducee(txn, c);
 
 		// Remove the contact group (all messages will be removed with it)
-		db.removeGroup(txn, getContactGroup(c));
+		db.removeGroup(txn, getContactGroup(c, getLocalAuthorId(txn)));
 	}
 
 	@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);
+		Group g = getContactGroup(c, getLocalAuthorId(txn));
 		db.setGroupVisibility(txn, c.getId(), g.getId(), v);
 	}
 
 	@Override
-	public Group getContactGroup(Contact c) {
+	public Group getContactGroup(Contact c, AuthorId local) {
 		return contactGroupFactory
-				.createContactGroup(CLIENT_ID, MAJOR_VERSION, c);
+				.createContactGroup(CLIENT_ID, MAJOR_VERSION, c, local);
 	}
 
 	@Override
@@ -328,17 +326,18 @@ class IntroductionManagerImpl extends ConversationClientImpl
 		try {
 			// Look up the session, if there is one
 			Author introducer = identityManager.getLocalAuthor(txn);
-			SessionId sessionId =
-					crypto.getSessionId(introducer, c1.getAuthor(),
-							c2.getAuthor());
+			SessionId sessionId = crypto.getSessionId(introducer,
+					c1.getAuthor(), c2.getAuthor());
 			StoredSession ss = getSession(txn, sessionId);
 			// Create or parse the session
 			IntroducerSession session;
 			MessageId storageId;
 			if (ss == null) {
 				// This is the first request - create a new session
-				GroupId groupId1 = getContactGroup(c1).getId();
-				GroupId groupId2 = getContactGroup(c2).getId();
+				GroupId groupId1 =
+						getContactGroup(c1, introducer.getId()).getId();
+				GroupId groupId2 =
+						getContactGroup(c2, introducer.getId()).getId();
 				boolean alice = crypto.isAlice(c1.getAuthor().getId(),
 						c2.getAuthor().getId());
 				// use fixed deterministic roles for the introducees
@@ -382,7 +381,8 @@ class IntroductionManagerImpl extends ConversationClientImpl
 			}
 			// Parse the session
 			Contact contact = db.getContact(txn, contactId);
-			GroupId contactGroupId = getContactGroup(contact).getId();
+			AuthorId local = getLocalAuthorId(txn);
+			GroupId contactGroupId = getContactGroup(contact, local).getId();
 			IntroduceeSession session = sessionParser
 					.parseIntroduceeSession(contactGroupId, ss.bdfSession);
 			// Handle the join or leave action
@@ -408,7 +408,8 @@ class IntroductionManagerImpl extends ConversationClientImpl
 			Transaction txn, ContactId c) throws DbException {
 		try {
 			Contact contact = db.getContact(txn, c);
-			GroupId contactGroupId = getContactGroup(contact).getId();
+			AuthorId local = getLocalAuthorId(txn);
+			GroupId contactGroupId = getContactGroup(contact, local).getId();
 			BdfDictionary query = messageParser.getMessagesVisibleInUiQuery();
 			Map<MessageId, BdfDictionary> results = clientHelper
 					.getMessageMetadataAsDictionary(txn, contactGroupId, query);
@@ -521,13 +522,11 @@ class IntroductionManagerImpl extends ConversationClientImpl
 		BdfDictionary query = sessionEncoder.getIntroducerSessionsQuery();
 		Map<MessageId, BdfDictionary> sessions;
 		try {
-			sessions = clientHelper
-					.getMessageMetadataAsDictionary(txn, localGroup.getId(),
-							query);
+			sessions = clientHelper.getMessageMetadataAsDictionary(txn,
+					localGroup.getId(), query);
 		} catch (FormatException e) {
 			throw new DbException();
 		}
-		LocalAuthor localAuthor = identityManager.getLocalAuthor(txn);
 		for (Entry<MessageId, BdfDictionary> session : sessions.entrySet()) {
 			IntroducerSession s;
 			try {
@@ -537,18 +536,18 @@ class IntroductionManagerImpl extends ConversationClientImpl
 			}
 			if (s.getIntroduceeA().author.equals(c.getAuthor())) {
 				abortOrRemoveSessionWithIntroducee(txn, s, session.getKey(),
-						s.getIntroduceeB(), localAuthor);
+						s.getIntroduceeB());
 			} else if (s.getIntroduceeB().author.equals(c.getAuthor())) {
 				abortOrRemoveSessionWithIntroducee(txn, s, session.getKey(),
-						s.getIntroduceeA(), localAuthor);
+						s.getIntroduceeA());
 			}
 		}
 	}
 
 	private void abortOrRemoveSessionWithIntroducee(Transaction txn,
-			IntroducerSession s, MessageId storageId, Introducee i,
-			LocalAuthor localAuthor) throws DbException {
-		if (db.containsContact(txn, i.author.getId(), localAuthor.getId())) {
+			IntroducerSession s, MessageId storageId, Introducee i)
+			throws DbException {
+		if (db.containsContact(txn, i.author.getId())) {
 			IntroducerSession session =
 					introducerEngine.onIntroduceeRemoved(txn, i, s);
 			storeSession(txn, storageId, session);

briar-core/src/main/java/org/briarproject/briar/messaging/MessagingManagerImpl.java

@@ -12,6 +12,8 @@ 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.Transaction;
+import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.Client;
 import org.briarproject.bramble.api.sync.Group;
@@ -59,8 +61,10 @@ class MessagingManagerImpl extends ConversationClientImpl
 	MessagingManagerImpl(DatabaseComponent db, ClientHelper clientHelper,
 			ClientVersioningManager clientVersioningManager,
 			MetadataParser metadataParser, MessageTracker messageTracker,
+			IdentityManager identityManager,
 			ContactGroupFactory contactGroupFactory) {
-		super(db, clientHelper, metadataParser, messageTracker);
+		super(db, clientHelper, metadataParser, messageTracker,
+				identityManager);
 		this.clientVersioningManager = clientVersioningManager;
 		this.contactGroupFactory = contactGroupFactory;
 	}
@@ -79,7 +83,7 @@ class MessagingManagerImpl extends ConversationClientImpl
 	@Override
 	public void addingContact(Transaction txn, Contact c) throws DbException {
 		// Create a group to share with the contact
-		Group g = getContactGroup(c);
+		Group g = getContactGroup(c, getLocalAuthorId(txn));
 		db.addGroup(txn, g);
 		// Apply the client's visibility to the contact group
 		Visibility client = clientVersioningManager.getClientVisibility(txn,
@@ -98,21 +102,21 @@ class MessagingManagerImpl extends ConversationClientImpl
 	}
 
 	@Override
-	public Group getContactGroup(Contact c) {
+	public Group getContactGroup(Contact c, AuthorId local) {
 		return contactGroupFactory.createContactGroup(CLIENT_ID,
-				MAJOR_VERSION, c);
+				MAJOR_VERSION, c, local);
 	}
 
 	@Override
 	public void removingContact(Transaction txn, Contact c) throws DbException {
-		db.removeGroup(txn, getContactGroup(c));
+		db.removeGroup(txn, getContactGroup(c, getLocalAuthorId(txn)));
 	}
 
 	@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);
+		Group g = getContactGroup(c, getLocalAuthorId(txn));
 		db.setGroupVisibility(txn, c.getId(), g.getId(), v);
 	}
 
@@ -188,15 +192,14 @@ class MessagingManagerImpl extends ConversationClientImpl
 
 	@Override
 	public GroupId getConversationId(ContactId c) throws DbException {
-		Contact contact;
-		Transaction txn = db.startTransaction(true);
-		try {
-			contact = db.getContact(txn, c);
-			db.commitTransaction(txn);
-		} finally {
-			db.endTransaction(txn);
-		}
-		return getContactGroup(contact).getId();
+		return db.transactionWithResult(true, txn -> getConversationId(txn, c));
+	}
+
+	private GroupId getConversationId(Transaction txn, ContactId c)
+		throws DbException {
+		Contact contact = db.getContact(txn, c);
+		AuthorId local = getLocalAuthorId(txn);
+		return getContactGroup(contact, local).getId();
 	}
 
 	@Override
@@ -206,7 +209,7 @@ class MessagingManagerImpl extends ConversationClientImpl
 		Collection<MessageStatus> statuses;
 		GroupId g;
 		try {
-			g = getContactGroup(db.getContact(txn, c)).getId();
+			g = getConversationId(txn, c);
 			metadata = clientHelper.getMessageMetadataAsDictionary(txn, g);
 			statuses = db.getMessageStatus(txn, c, g);
 		} catch (FormatException e) {

briar-core/src/main/java/org/briarproject/briar/privategroup/PrivateGroupManagerImpl.java

@@ -17,8 +17,6 @@ import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.identity.AuthorInfo;
 import org.briarproject.bramble.api.identity.AuthorInfo.Status;
-import org.briarproject.bramble.api.identity.IdentityManager;
-import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.Group;
 import org.briarproject.bramble.api.sync.GroupId;
@@ -83,7 +81,6 @@ class PrivateGroupManagerImpl extends BdfIncomingMessageHook
 
 	private final PrivateGroupFactory privateGroupFactory;
 	private final ContactManager contactManager;
-	private final IdentityManager identityManager;
 	private final MessageTracker messageTracker;
 	private final List<PrivateGroupHook> hooks;
 
@@ -91,12 +88,10 @@ class PrivateGroupManagerImpl extends BdfIncomingMessageHook
 	PrivateGroupManagerImpl(ClientHelper clientHelper,
 			MetadataParser metadataParser, DatabaseComponent db,
 			PrivateGroupFactory privateGroupFactory,
-			ContactManager contactManager, IdentityManager identityManager,
-			MessageTracker messageTracker) {
+			ContactManager contactManager, MessageTracker messageTracker) {
 		super(db, clientHelper, metadataParser);
 		this.privateGroupFactory = privateGroupFactory;
 		this.contactManager = contactManager;
-		this.identityManager = identityManager;
 		this.messageTracker = messageTracker;
 		hooks = new CopyOnWriteArrayList<>();
 	}
@@ -398,18 +393,17 @@ class PrivateGroupManagerImpl extends BdfIncomingMessageHook
 		try {
 			Collection<GroupMember> members = new ArrayList<>();
 			Map<Author, Visibility> authors = getMembers(txn, g);
-			LocalAuthor la = identityManager.getLocalAuthor(txn);
 			PrivateGroup privateGroup = getPrivateGroup(txn, g);
 			for (Entry<Author, Visibility> m : authors.entrySet()) {
 				Author a = m.getKey();
-				AuthorInfo authorInfo = contactManager.getAuthorInfo(txn, a.getId());
+				AuthorInfo authorInfo =
+						contactManager.getAuthorInfo(txn, a.getId());
 				Status status = authorInfo.getStatus();
 				Visibility v = m.getValue();
 				ContactId c = null;
 				if (v != INVISIBLE &&
 						(status == VERIFIED || status == UNVERIFIED)) {
-					c = contactManager.getContact(txn, a.getId(), la.getId())
-							.getId();
+					c = contactManager.getContact(txn, a.getId()).getId();
 				}
 				boolean isCreator = privateGroup.getCreator().equals(a);
 				members.add(new GroupMember(a, authorInfo, isCreator, c, v));
@@ -483,8 +477,7 @@ class PrivateGroupManagerImpl extends BdfIncomingMessageHook
 		if (!foundMember) throw new ProtocolStateException();
 		if (changed) {
 			clientHelper.mergeGroupMetadata(txn, g, meta);
-			LocalAuthor la = identityManager.getLocalAuthor(txn);
-			ContactId c = contactManager.getContact(txn, a, la.getId()).getId();
+			ContactId c = contactManager.getContact(txn, a).getId();
 			Event e = new ContactRelationshipRevealedEvent(g, a, c, v);
 			txn.attach(e);
 		}

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/GroupInvitationFactoryImpl.java

@@ -6,6 +6,7 @@ import org.briarproject.bramble.api.client.ContactGroupFactory;
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.Group;
 import org.briarproject.bramble.api.sync.GroupId;
@@ -34,14 +35,15 @@ class GroupInvitationFactoryImpl implements GroupInvitationFactory {
 	}
 
 	@Override
-	public byte[] signInvitation(Contact c, GroupId privateGroupId,
-			long timestamp, byte[] privateKey) {
-		AuthorId creatorId = c.getLocalAuthorId();
-		AuthorId memberId = c.getAuthor().getId();
+	public byte[] signInvitation(LocalAuthor creator, Contact member,
+			GroupId privateGroupId, long timestamp) {
+		AuthorId creatorId = creator.getId();
+		AuthorId memberId = member.getAuthor().getId();
 		BdfList token = createInviteToken(creatorId, memberId, privateGroupId,
 				timestamp);
 		try {
-			return clientHelper.sign(SIGNING_LABEL_INVITE, token, privateKey);
+			return clientHelper.sign(SIGNING_LABEL_INVITE, token,
+					creator.getPrivateKey());
 		} catch (GeneralSecurityException e) {
 			throw new IllegalArgumentException(e);
 		} catch (FormatException e) {

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/GroupInvitationManagerImpl.java

@@ -14,6 +14,8 @@ 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.identity.Author;
+import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.Client;
 import org.briarproject.bramble.api.sync.Group;
@@ -81,13 +83,15 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 			ClientHelper clientHelper,
 			ClientVersioningManager clientVersioningManager,
 			MetadataParser metadataParser, MessageTracker messageTracker,
+			IdentityManager identityManager,
 			ContactGroupFactory contactGroupFactory,
 			PrivateGroupFactory privateGroupFactory,
 			PrivateGroupManager privateGroupManager,
 			MessageParser messageParser, SessionParser sessionParser,
 			SessionEncoder sessionEncoder,
 			ProtocolEngineFactory engineFactory) {
-		super(db, clientHelper, metadataParser, messageTracker);
+		super(db, clientHelper, metadataParser, messageTracker,
+				identityManager);
 		this.clientVersioningManager = clientVersioningManager;
 		this.contactGroupFactory = contactGroupFactory;
 		this.privateGroupFactory = privateGroupFactory;
@@ -114,7 +118,7 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 	@Override
 	public void addingContact(Transaction txn, Contact c) throws DbException {
 		// Create a group to share with the contact
-		Group g = getContactGroup(c);
+		Group g = getContactGroup(c, getLocalAuthorId(txn));
 		db.addGroup(txn, g);
 		Visibility client = clientVersioningManager.getClientVisibility(txn,
 				c.getId(), CLIENT_ID, MAJOR_VERSION);
@@ -138,13 +142,13 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 	@Override
 	public void removingContact(Transaction txn, Contact c) throws DbException {
 		// Remove the contact group (all messages will be removed with it)
-		db.removeGroup(txn, getContactGroup(c));
+		db.removeGroup(txn, getContactGroup(c, getLocalAuthorId(txn)));
 	}
 
 	@Override
-	public Group getContactGroup(Contact c) {
+	public Group getContactGroup(Contact c, AuthorId local) {
 		return contactGroupFactory.createContactGroup(CLIENT_ID,
-				MAJOR_VERSION, c);
+				MAJOR_VERSION, c, local);
 	}
 
 	@Override
@@ -267,7 +271,8 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 		try {
 			// Look up the session, if there is one
 			Contact contact = db.getContact(txn, c);
-			GroupId contactGroupId = getContactGroup(contact).getId();
+			AuthorId local = getLocalAuthorId(txn);
+			GroupId contactGroupId = getContactGroup(contact, local).getId();
 			StoredSession ss = getSession(txn, contactGroupId, sessionId);
 			// Create or parse the session
 			CreatorSession session;
@@ -308,7 +313,8 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 		try {
 			// Look up the session
 			Contact contact = db.getContact(txn, c);
-			GroupId contactGroupId = getContactGroup(contact).getId();
+			AuthorId local = getLocalAuthorId(txn);
+			GroupId contactGroupId = getContactGroup(contact, local).getId();
 			StoredSession ss = getSession(txn, contactGroupId, sessionId);
 			if (ss == null) throw new IllegalArgumentException();
 			// Parse the session
@@ -333,7 +339,8 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 		try {
 			// Look up the session
 			Contact contact = db.getContact(txn, c);
-			GroupId contactGroupId = getContactGroup(contact).getId();
+			AuthorId local = getLocalAuthorId(txn);
+			GroupId contactGroupId = getContactGroup(contact, local).getId();
 			StoredSession ss = getSession(txn, contactGroupId, getSessionId(g));
 			if (ss == null) throw new IllegalArgumentException();
 			// Parse the session
@@ -368,11 +375,12 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 	}
 
 	@Override
-	public Collection<ConversationMessageHeader> getMessageHeaders(Transaction txn,
-			ContactId c) throws DbException {
+	public Collection<ConversationMessageHeader> getMessageHeaders(
+			Transaction txn, ContactId c) throws DbException {
 		try {
 			Contact contact = db.getContact(txn, c);
-			GroupId contactGroupId = getContactGroup(contact).getId();
+			AuthorId local = getLocalAuthorId(txn);
+			GroupId contactGroupId = getContactGroup(contact, local).getId();
 			BdfDictionary query = messageParser.getMessagesVisibleInUiQuery();
 			Map<MessageId, BdfDictionary> results = clientHelper
 					.getMessageMetadataAsDictionary(txn, contactGroupId, query);
@@ -436,8 +444,9 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 		Transaction txn = db.startTransaction(true);
 		try {
 			// Look up the available invite messages for each contact
+			AuthorId local = getLocalAuthorId(txn);
 			for (Contact c : db.getContacts(txn)) {
-				GroupId contactGroupId = getContactGroup(c).getId();
+				GroupId contactGroupId = getContactGroup(c, local).getId();
 				Map<MessageId, BdfDictionary> results =
 						clientHelper.getMessageMetadataAsDictionary(txn,
 								contactGroupId, query);
@@ -456,10 +465,11 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 	@Override
 	public boolean isInvitationAllowed(Contact c, GroupId privateGroupId)
 			throws DbException {
-		GroupId contactGroupId = getContactGroup(c).getId();
 		SessionId sessionId = getSessionId(privateGroupId);
 		Transaction txn = db.startTransaction(true);
 		try {
+			AuthorId local = getLocalAuthorId(txn);
+			GroupId contactGroupId = getContactGroup(c, local).getId();
 			Visibility client = clientVersioningManager.getClientVisibility(txn,
 					c.getId(), PrivateGroupManager.CLIENT_ID,
 					PrivateGroupManager.MAJOR_VERSION);
@@ -492,15 +502,17 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 	public void addingMember(Transaction txn, GroupId privateGroupId, Author a)
 			throws DbException {
 		// If the member is a contact, handle the add member action
-		for (Contact c : db.getContactsByAuthorId(txn, a.getId()))
-			addingMember(txn, privateGroupId, c);
+		if (db.containsContact(txn, a.getId())) {
+			addingMember(txn, privateGroupId, db.getContact(txn, a.getId()));
+		}
 	}
 
 	private void addingMember(Transaction txn, GroupId privateGroupId,
 			Contact c) throws DbException {
 		try {
 			// Look up the session for the contact, if there is one
-			GroupId contactGroupId = getContactGroup(c).getId();
+			AuthorId local = getLocalAuthorId(txn);
+			GroupId contactGroupId = getContactGroup(c, local).getId();
 			SessionId sessionId = getSessionId(privateGroupId);
 			StoredSession ss = getSession(txn, contactGroupId, sessionId);
 			// Create or parse the session
@@ -533,9 +545,10 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 		SessionId sessionId = getSessionId(privateGroupId);
 		// If we have any sessions in progress, tell the contacts we're leaving
 		try {
+			AuthorId local = getLocalAuthorId(txn);
 			for (Contact c : db.getContacts(txn)) {
 				// Look up the session for the contact, if there is one
-				GroupId contactGroupId = getContactGroup(c).getId();
+				GroupId contactGroupId = getContactGroup(c, local).getId();
 				StoredSession ss = getSession(txn, contactGroupId, sessionId);
 				if (ss == null) continue; // No session for this contact
 				// Handle the action
@@ -574,7 +587,7 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 	public void onClientVisibilityChanging(Transaction txn, Contact c,
 			Visibility v) throws DbException {
 		// Apply the client's visibility to the contact group
-		Group g = getContactGroup(c);
+		Group g = getContactGroup(c, getLocalAuthorId(txn));
 		db.setGroupVisibility(txn, c.getId(), g.getId(), v);
 	}
 
@@ -603,7 +616,8 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 
 	private Map<GroupId, Visibility> getPreferredVisibilities(Transaction txn,
 			Contact c) throws DbException, FormatException {
-		GroupId contactGroupId = getContactGroup(c).getId();
+		AuthorId local = getLocalAuthorId(txn);
+		GroupId contactGroupId = getContactGroup(c, local).getId();
 		BdfDictionary query = sessionParser.getAllSessionsQuery();
 		Map<MessageId, BdfDictionary> results = clientHelper
 				.getMessageMetadataAsDictionary(txn, contactGroupId, query);

briar-core/src/main/java/org/briarproject/briar/sharing/BlogSharingManagerImpl.java

@@ -28,7 +28,6 @@ import javax.inject.Inject;
 class BlogSharingManagerImpl extends SharingManagerImpl<Blog>
 		implements BlogSharingManager, RemoveBlogHook {
 
-	private final IdentityManager identityManager;
 	private final BlogManager blogManager;
 
 	@Inject
@@ -43,8 +42,8 @@ class BlogSharingManagerImpl extends SharingManagerImpl<Blog>
 			IdentityManager identityManager, BlogManager blogManager) {
 		super(db, clientHelper, clientVersioningManager, metadataParser,
 				messageParser, sessionEncoder, sessionParser, messageTracker,
-				contactGroupFactory, engine, invitationFactory);
-		this.identityManager = identityManager;
+				identityManager, contactGroupFactory, engine,
+				invitationFactory);
 		this.blogManager = blogManager;
 	}
 
@@ -80,8 +79,8 @@ class BlogSharingManagerImpl extends SharingManagerImpl<Blog>
 
 		// Pre-share both blogs, if they have not been shared already
 		try {
-			preShareGroup(txn, c, ourBlog.getGroup());
-			preShareGroup(txn, c, theirBlog.getGroup());
+			preShareGroup(txn, c, ourBlog.getGroup(), localAuthor.getId());
+			preShareGroup(txn, c, theirBlog.getGroup(), localAuthor.getId());
 		} catch (FormatException e) {
 			throw new DbException(e);
 		}

briar-core/src/main/java/org/briarproject/briar/sharing/ForumSharingManagerImpl.java

@@ -6,6 +6,7 @@ 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.Transaction;
+import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.ClientId;
 import org.briarproject.bramble.api.versioning.ClientVersioningManager;
@@ -27,13 +28,14 @@ class ForumSharingManagerImpl extends SharingManagerImpl<Forum>
 			ClientVersioningManager clientVersioningManager,
 			MetadataParser metadataParser, MessageParser<Forum> messageParser,
 			SessionEncoder sessionEncoder, SessionParser sessionParser,
-			MessageTracker messageTracker,
+			MessageTracker messageTracker, IdentityManager identityManager,
 			ContactGroupFactory contactGroupFactory,
 			ProtocolEngine<Forum> engine,
 			InvitationFactory<Forum, ForumInvitationResponse> invitationFactory) {
 		super(db, clientHelper, clientVersioningManager, metadataParser,
 				messageParser, sessionEncoder, sessionParser, messageTracker,
-				contactGroupFactory, engine, invitationFactory);
+				identityManager, contactGroupFactory, engine,
+				invitationFactory);
 	}
 
 	@Override

briar-core/src/main/java/org/briarproject/briar/sharing/SharingManagerImpl.java

@@ -13,6 +13,8 @@ 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.identity.AuthorId;
+import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.Client;
 import org.briarproject.bramble.api.sync.ClientId;
@@ -70,10 +72,11 @@ abstract class SharingManagerImpl<S extends Shareable>
 			ClientVersioningManager clientVersioningManager,
 			MetadataParser metadataParser, MessageParser<S> messageParser,
 			SessionEncoder sessionEncoder, SessionParser sessionParser,
-			MessageTracker messageTracker,
+			MessageTracker messageTracker, IdentityManager identityManager,
 			ContactGroupFactory contactGroupFactory, ProtocolEngine<S> engine,
 			InvitationFactory<S, ?> invitationFactory) {
-		super(db, clientHelper, metadataParser, messageTracker);
+		super(db, clientHelper, metadataParser, messageTracker,
+				identityManager);
 		this.clientVersioningManager = clientVersioningManager;
 		this.messageParser = messageParser;
 		this.sessionEncoder = sessionEncoder;
@@ -105,7 +108,7 @@ abstract class SharingManagerImpl<S extends Shareable>
 	@Override
 	public void addingContact(Transaction txn, Contact c) throws DbException {
 		// Create a group to share with the contact
-		Group g = getContactGroup(c);
+		Group g = getContactGroup(c, getLocalAuthorId(txn));
 		db.addGroup(txn, g);
 		Visibility client = clientVersioningManager.getClientVisibility(txn,
 				c.getId(), getClientId(), getMajorVersion());
@@ -123,13 +126,13 @@ abstract class SharingManagerImpl<S extends Shareable>
 	@Override
 	public void removingContact(Transaction txn, Contact c) throws DbException {
 		// Remove the contact group (all messages will be removed with it)
-		db.removeGroup(txn, getContactGroup(c));
+		db.removeGroup(txn, getContactGroup(c, getLocalAuthorId(txn)));
 	}
 
 	@Override
-	public Group getContactGroup(Contact c) {
+	public Group getContactGroup(Contact c, AuthorId local) {
 		return contactGroupFactory.createContactGroup(getClientId(),
-				getMajorVersion(), c);
+				getMajorVersion(), c, local);
 	}
 
 	@Override
@@ -160,10 +163,10 @@ abstract class SharingManagerImpl<S extends Shareable>
 	 * and the Contact c in state SHARING.
 	 * If a session already exists, this does nothing.
 	 */
-	void preShareGroup(Transaction txn, Contact c, Group g)
+	void preShareGroup(Transaction txn, Contact c, Group g, AuthorId local)
 			throws DbException, FormatException {
 		// Return if a session already exists with the contact
-		GroupId contactGroupId = getContactGroup(c).getId();
+		GroupId contactGroupId = getContactGroup(c, local).getId();
 		StoredSession existingSession = getSession(txn, contactGroupId,
 				getSessionId(g.getId()));
 		if (existingSession != null) return;
@@ -257,11 +260,13 @@ abstract class SharingManagerImpl<S extends Shareable>
 		Transaction txn = db.startTransaction(false);
 		try {
 			Contact contact = db.getContact(txn, contactId);
-			if (!canBeShared(txn, shareableId, contact))
+			if (!canBeShared(txn, shareableId, contact)) {
 				// we might have received an invitation in the meantime
 				return;
+			}
 			// Look up the session, if there is one
-			GroupId contactGroupId = getContactGroup(contact).getId();
+			AuthorId local = getLocalAuthorId(txn);
+			GroupId contactGroupId = getContactGroup(contact, local).getId();
 			StoredSession ss = getSession(txn, contactGroupId, sessionId);
 			// Create or parse the session
 			Session session;
@@ -301,7 +306,8 @@ abstract class SharingManagerImpl<S extends Shareable>
 		try {
 			// Look up the session
 			Contact contact = db.getContact(txn, c);
-			GroupId contactGroupId = getContactGroup(contact).getId();
+			AuthorId local = getLocalAuthorId(txn);
+			GroupId contactGroupId = getContactGroup(contact, local).getId();
 			StoredSession ss = getSession(txn, contactGroupId, id);
 			if (ss == null) throw new IllegalArgumentException();
 			// Parse the session
@@ -325,7 +331,8 @@ abstract class SharingManagerImpl<S extends Shareable>
 			Transaction txn, ContactId c) throws DbException {
 		try {
 			Contact contact = db.getContact(txn, c);
-			GroupId contactGroupId = getContactGroup(contact).getId();
+			AuthorId local = getLocalAuthorId(txn);
+			GroupId contactGroupId = getContactGroup(contact, local).getId();
 			BdfDictionary query = messageParser.getMessagesVisibleInUiQuery();
 			Map<MessageId, BdfDictionary> results = clientHelper
 					.getMessageMetadataAsDictionary(txn, contactGroupId, query);
@@ -385,8 +392,9 @@ abstract class SharingManagerImpl<S extends Shareable>
 		Transaction txn = db.startTransaction(true);
 		try {
 			// get invitations from each contact
+			AuthorId local = getLocalAuthorId(txn);
 			for (Contact c : db.getContacts(txn)) {
-				GroupId contactGroupId = getContactGroup(c).getId();
+				GroupId contactGroupId = getContactGroup(c, local).getId();
 				Map<MessageId, BdfDictionary> results =
 						clientHelper.getMessageMetadataAsDictionary(txn,
 								contactGroupId, query);
@@ -456,7 +464,8 @@ abstract class SharingManagerImpl<S extends Shareable>
 		Visibility client = clientVersioningManager.getClientVisibility(txn,
 				c.getId(), getShareableClientId(), getShareableMajorVersion());
 		if (client != SHARED) return false;
-		GroupId contactGroupId = getContactGroup(c).getId();
+		AuthorId local = getLocalAuthorId(txn);
+		GroupId contactGroupId = getContactGroup(c, local).getId();
 		SessionId sessionId = getSessionId(g);
 		try {
 			StoredSession ss = getSession(txn, contactGroupId, sessionId);
@@ -475,9 +484,10 @@ abstract class SharingManagerImpl<S extends Shareable>
 		SessionId sessionId = getSessionId(shareable.getId());
 		// If we have any sessions in progress, tell the contacts we're leaving
 		try {
+			AuthorId local = getLocalAuthorId(txn);
 			for (Contact c : db.getContacts(txn)) {
 				// Look up the session for the contact, if there is one
-				GroupId contactGroupId = getContactGroup(c).getId();
+				GroupId contactGroupId = getContactGroup(c, local).getId();
 				StoredSession ss = getSession(txn, contactGroupId, sessionId);
 				if (ss == null) continue; // No session for this contact
 				// Let the engine perform a LEAVE action
@@ -496,7 +506,7 @@ abstract class SharingManagerImpl<S extends Shareable>
 	public void onClientVisibilityChanging(Transaction txn, Contact c,
 			Visibility v) throws DbException {
 		// Apply the client's visibility to the contact group
-		Group g = getContactGroup(c);
+		Group g = getContactGroup(c, getLocalAuthorId(txn));
 		db.setGroupVisibility(txn, c.getId(), g.getId(), v);
 	}
 
@@ -525,7 +535,8 @@ abstract class SharingManagerImpl<S extends Shareable>
 
 	private Map<GroupId, Visibility> getPreferredVisibilities(Transaction txn,
 			Contact c) throws DbException, FormatException {
-		GroupId contactGroupId = getContactGroup(c).getId();
+		AuthorId local = getLocalAuthorId(txn);
+		GroupId contactGroupId = getContactGroup(c, local).getId();
 		BdfDictionary query = sessionParser.getAllSessionsQuery();
 		Map<MessageId, BdfDictionary> results = clientHelper
 				.getMessageMetadataAsDictionary(txn, contactGroupId, query);

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

@@ -13,7 +13,6 @@ import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.AuthorFactory;
-import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
@@ -148,17 +147,15 @@ public class TestDataCreatorImpl implements TestDataCreator {
 
 	private List<Contact> createContacts(int numContacts) throws DbException {
 		List<Contact> contacts = new ArrayList<>(numContacts);
-		LocalAuthor localAuthor = identityManager.getLocalAuthor();
 		for (int i = 0; i < numContacts; i++) {
 			LocalAuthor author = getRandomAuthor();
-			Contact contact = addContact(localAuthor.getId(), author);
+			Contact contact = addContact(author);
 			contacts.add(contact);
 		}
 		return contacts;
 	}
 
-	private Contact addContact(AuthorId localAuthorId, LocalAuthor author)
-			throws DbException {
+	private Contact addContact(LocalAuthor author) throws DbException {
 
 		// prepare to add contact
 		SecretKey secretKey = getSecretKey();
@@ -172,9 +169,8 @@ public class TestDataCreatorImpl implements TestDataCreator {
 		Contact contact;
 		Transaction txn = db.startTransaction(false);
 		try {
-			ContactId contactId = contactManager
-					.addContact(txn, author, localAuthorId, secretKey,
-							timestamp, true, verified, true);
+			ContactId contactId = contactManager.addContact(txn, author,
+					secretKey, timestamp, true, verified, true);
 			if (random.nextBoolean()) {
 				contactManager
 						.setContactAlias(txn, contactId, getRandomAuthorName());
@@ -196,8 +192,7 @@ public class TestDataCreatorImpl implements TestDataCreator {
 
 	@Override
 	public Contact addContact(String name) throws DbException {
-		LocalAuthor localAuthor = identityManager.getLocalAuthor();
-		return addContact(localAuthor.getId(), getAuthor(name));
+		return addContact(getAuthor(name));
 	}
 
 	private LocalAuthor getAuthor(String name) {
@@ -301,8 +296,10 @@ public class TestDataCreatorImpl implements TestDataCreator {
 
 	private void createPrivateMessages(List<Contact> contacts,
 			int numPrivateMsgs) throws DbException {
+		LocalAuthor localAuthor = identityManager.getLocalAuthor();
 		for (Contact contact : contacts) {
-			Group group = messagingManager.getContactGroup(contact);
+			Group group = messagingManager.getContactGroup(contact,
+					localAuthor.getId());
 			for (int i = 0; i < numPrivateMsgs; i++) {
 				try {
 					createRandomPrivateMessage(group.getId(), i);
@@ -345,13 +342,6 @@ public class TestDataCreatorImpl implements TestDataCreator {
 		}
 	}
 
-	@Override
-	public void addPrivateMessage(Contact contact, String text, long time,
-			boolean local) throws DbException, FormatException {
-		Group group = messagingManager.getContactGroup(contact);
-		createPrivateMessage(group.getId(), text, time, local);
-	}
-
 	private void createBlogPosts(List<Contact> contacts, int numBlogPosts)
 			throws DbException {
 		for (int i = 0; i < numBlogPosts; i++) {

briar-core/src/test/java/org/briarproject/briar/blog/BlogManagerImplTest.java

@@ -130,8 +130,7 @@ public class BlogManagerImplTest extends BriarTestCase {
 	@Test
 	public void testRemovingContact() throws DbException {
 		Transaction txn = new Transaction(null, false);
-		Contact contact = getContact(blog2.getAuthor(),
-				blog1.getAuthor().getId(), true);
+		Contact contact = getContact(blog2.getAuthor(), true);
 
 		context.checking(new Expectations() {{
 			oneOf(blogFactory).createBlog(blog2.getAuthor());
@@ -150,8 +149,7 @@ public class BlogManagerImplTest extends BriarTestCase {
 	@Test
 	public void testRemovingContactAfterRemovingBlog() throws DbException {
 		Transaction txn = new Transaction(null, false);
-		Contact contact = getContact(blog2.getAuthor(),
-				blog1.getAuthor().getId(), true);
+		Contact contact = getContact(blog2.getAuthor(), true);
 
 		context.checking(new Expectations() {{
 			oneOf(blogFactory).createBlog(blog2.getAuthor());

briar-core/src/test/java/org/briarproject/briar/introduction/IntroductionIntegrationTest.java

@@ -14,6 +14,7 @@ import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
@@ -134,8 +135,10 @@ public class IntroductionIntegrationTest
 				.makeIntroduction(introducee1, introducee2, "Hi!", time);
 
 		// check that messages are tracked properly
-		Group g1 = introductionManager0.getContactGroup(introducee1);
-		Group g2 = introductionManager0.getContactGroup(introducee2);
+		Group g1 = introductionManager0.getContactGroup(introducee1,
+				author0.getId());
+		Group g2 = introductionManager0.getContactGroup(introducee2,
+				author0.getId());
 		assertGroupCount(messageTracker0, g1.getId(), 1, 0);
 		assertGroupCount(messageTracker0, g2.getId(), 1, 0);
 
@@ -228,10 +231,8 @@ public class IntroductionIntegrationTest
 		assertTrue(listener1.succeeded);
 		assertTrue(listener2.succeeded);
 
-		assertTrue(contactManager1
-				.contactExists(author2.getId(), author1.getId()));
-		assertTrue(contactManager2
-				.contactExists(author1.getId(), author2.getId()));
+		assertTrue(contactManager1.contactExists(author2.getId()));
+		assertTrue(contactManager2.contactExists(author1.getId()));
 
 		// make sure that introduced contacts are not verified
 		for (Contact c : contactManager1.getContacts()) {
@@ -318,13 +319,13 @@ public class IntroductionIntegrationTest
 		assertFalse(listener1.succeeded);
 		assertFalse(listener2.succeeded);
 
-		assertFalse(contactManager1
-				.contactExists(author2.getId(), author1.getId()));
-		assertFalse(contactManager2
-				.contactExists(author1.getId(), author2.getId()));
+		assertFalse(contactManager1.contactExists(author2.getId()));
+		assertFalse(contactManager2.contactExists(author1.getId()));
 
-		Group g1 = introductionManager0.getContactGroup(introducee1);
-		Group g2 = introductionManager0.getContactGroup(introducee2);
+		Group g1 = introductionManager0.getContactGroup(introducee1,
+				author0.getId());
+		Group g2 = introductionManager0.getContactGroup(introducee2,
+				author0.getId());
 		Collection<ConversationMessageHeader> messages =
 				db0.transactionWithResult(true, txn -> introductionManager0
 						.getMessageHeaders(txn, contactId1From0));
@@ -387,10 +388,8 @@ public class IntroductionIntegrationTest
 				listener1.getResponse().getIntroducedAuthor().getName());
 		assertFalse(listener1.getResponse().canSucceed());
 
-		assertFalse(contactManager1
-				.contactExists(author2.getId(), author1.getId()));
-		assertFalse(contactManager2
-				.contactExists(author1.getId(), author2.getId()));
+		assertFalse(contactManager1.contactExists(author2.getId()));
+		assertFalse(contactManager2.contactExists(author1.getId()));
 
 		Collection<ConversationMessageHeader> messages =
 				db0.transactionWithResult(true, txn -> introductionManager0
@@ -499,10 +498,8 @@ public class IntroductionIntegrationTest
 		sync1To0(2, true);
 		sync0To2(2, true);
 
-		assertTrue(contactManager1
-				.contactExists(author2.getId(), author1.getId()));
-		assertTrue(contactManager2
-				.contactExists(author1.getId(), author2.getId()));
+		assertTrue(contactManager1.contactExists(author2.getId()));
+		assertTrue(contactManager2.contactExists(author1.getId()));
 
 		assertDefaultUiMessages();
 		assertFalse(listener0.aborted);
@@ -593,8 +590,10 @@ public class IntroductionIntegrationTest
 		introduceeSession = getIntroduceeSession(c1);
 		assertEquals(IntroduceeState.START, introduceeSession.getState());
 
-		Group g1 = introductionManager0.getContactGroup(introducee1);
-		Group g2 = introductionManager0.getContactGroup(introducee2);
+		Group g1 = introductionManager0.getContactGroup(introducee1,
+				author0.getId());
+		Group g2 = introductionManager0.getContactGroup(introducee2,
+				author0.getId());
 		assertEquals(2, db0.transactionWithResult(true, txn ->
 				introductionManager0.getMessageHeaders(txn, contactId1From0))
 				.size());
@@ -787,8 +786,8 @@ public class IntroductionIntegrationTest
 		sync0To1(1, true);
 
 		// save ACCEPT from introducee1
-		AcceptMessage m = (AcceptMessage) getMessageFor(c1.getClientHelper(),
-				contact0From1, ACCEPT);
+		AcceptMessage m = (AcceptMessage) getMessageFor(introductionManager1,
+				c1.getClientHelper(), contact0From1, author1.getId(), ACCEPT);
 
 		// sync ACCEPT back to introducer
 		sync1To0(1, true);
@@ -824,8 +823,8 @@ public class IntroductionIntegrationTest
 		sync0To1(1, true);
 
 		// save ACCEPT from introducee1
-		AcceptMessage m = (AcceptMessage) getMessageFor(c1.getClientHelper(),
-				contact0From1, ACCEPT);
+		AcceptMessage m = (AcceptMessage) getMessageFor(introductionManager1,
+				c1.getClientHelper(), contact0From1, author1.getId(), ACCEPT);
 
 		// sync ACCEPT back to introducer
 		sync1To0(1, true);
@@ -859,8 +858,8 @@ public class IntroductionIntegrationTest
 		sync0To1(1, true);
 
 		// save DECLINE from introducee1
-		DeclineMessage m = (DeclineMessage) getMessageFor(c1.getClientHelper(),
-				contact0From1, DECLINE);
+		DeclineMessage m = (DeclineMessage) getMessageFor(introductionManager1,
+				c1.getClientHelper(), contact0From1, author1.getId(), DECLINE);
 
 		// sync DECLINE back to introducer
 		sync1To0(1, true);
@@ -903,8 +902,8 @@ public class IntroductionIntegrationTest
 		sync0To2(1, true);
 
 		// save AUTH from introducee1
-		AuthMessage m = (AuthMessage) getMessageFor(c1.getClientHelper(),
-				contact0From1, AUTH);
+		AuthMessage m = (AuthMessage) getMessageFor(introductionManager1,
+				c1.getClientHelper(), contact0From1, author1.getId(), AUTH);
 
 		// sync first AUTH message
 		sync1To0(1, true);
@@ -1006,13 +1005,11 @@ public class IntroductionIntegrationTest
 		// 0 and 1 remove and re-add each other
 		contactManager0.removeContact(contactId1From0);
 		contactManager1.removeContact(contactId0From1);
-		contactId1From0 = contactManager0
-				.addContact(author1, author0.getId(), getSecretKey(),
-						clock.currentTimeMillis(), true, true, true);
+		contactId1From0 = contactManager0.addContact(author1, getSecretKey(),
+				clock.currentTimeMillis(), true, true, true);
 		contact1From0 = contactManager0.getContact(contactId1From0);
-		contactId0From1 = contactManager1
-				.addContact(author0, author1.getId(), getSecretKey(),
-						clock.currentTimeMillis(), true, true, true);
+		contactId0From1 = contactManager1.addContact(author0, getSecretKey(),
+				clock.currentTimeMillis(), true, true, true);
 		contact0From1 = contactManager1.getContact(contactId0From1);
 
 		// Sync initial client versioning updates and transport properties
@@ -1060,9 +1057,9 @@ public class IntroductionIntegrationTest
 		eventWaiter.await(TIMEOUT, 1);
 
 		// get response to be forwarded
-		AcceptMessage message =
-				(AcceptMessage) getMessageFor(c0.getClientHelper(),
-						contact2From0, ACCEPT);
+		AcceptMessage message = (AcceptMessage) getMessageFor(
+				introductionManager0, c0.getClientHelper(), contact2From0,
+				author0.getId(), ACCEPT);
 
 		// allow visitor to modify response
 		AcceptMessage m = visitor.visit(message);
@@ -1345,10 +1342,10 @@ public class IntroductionIntegrationTest
 		}
 	}
 
-	private AbstractIntroductionMessage getMessageFor(ClientHelper ch,
-			Contact contact, MessageType type)
+	private AbstractIntroductionMessage getMessageFor(IntroductionManager im,
+			ClientHelper ch, Contact contact, AuthorId local, MessageType type)
 			throws FormatException, DbException {
-		Group g = introductionManager0.getContactGroup(contact);
+		Group g = im.getContactGroup(contact, local);
 		BdfDictionary query = BdfDictionary.of(
 				new BdfEntry(MSG_KEY_MESSAGE_TYPE, type.getValue())
 		);
@@ -1400,8 +1397,8 @@ public class IntroductionIntegrationTest
 				.getMessageMetadataAsDictionary(getLocalGroup().getId());
 		assertEquals(1, dicts.size());
 		BdfDictionary d = dicts.values().iterator().next();
-		Group introducerGroup =
-				introductionManager2.getContactGroup(contact0From2);
+		Group introducerGroup = introductionManager2
+				.getContactGroup(contact0From2, author2.getId());
 		return c.getSessionParser()
 				.parseIntroduceeSession(introducerGroup.getId(), d);
 	}

briar-core/src/test/java/org/briarproject/briar/messaging/SimplexMessagingIntegrationTest.java

@@ -110,8 +110,8 @@ public class SimplexMessagingIntegrationTest extends BriarTestCase {
 		lifecycleManager.waitForStartup();
 		// Add the other user as a contact
 		ContactManager contactManager = device.getContactManager();
-		return contactManager.addContact(remote, local.getId(), rootKey,
-				timestamp, alice, true, true);
+		return contactManager.addContact(remote, rootKey, timestamp, alice,
+				true, true);
 	}
 
 	private void sendMessage(SimplexMessagingIntegrationTestComponent device,

briar-core/src/test/java/org/briarproject/briar/privategroup/PrivateGroupIntegrationTest.java

@@ -29,6 +29,7 @@ import static org.briarproject.briar.api.privategroup.Visibility.INVISIBLE;
 import static org.briarproject.briar.api.privategroup.Visibility.REVEALED_BY_CONTACT;
 import static org.briarproject.briar.api.privategroup.Visibility.REVEALED_BY_US;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 
 /**
@@ -164,7 +165,7 @@ public class PrivateGroupIntegrationTest
 				getGroupMember(groupManager2, author1.getId()).getVisibility());
 
 		// 1 reveals the contact relationship to 2
-		assertTrue(contactId2From1 != null);
+		assertNotNull(contactId2From1);
 		groupInvitationManager1.revealRelationship(contactId2From1, groupId0);
 		sync1To2(1, true);
 		sync2To1(1, true);
@@ -213,8 +214,7 @@ public class PrivateGroupIntegrationTest
 			@Nullable String text) throws DbException {
 		Contact contact = contactManager0.getContact(c);
 		byte[] signature = groupInvitationFactory
-				.signInvitation(contact, groupId0, timestamp,
-						author0.getPrivateKey());
+				.signInvitation(author0, contact, groupId0, timestamp);
 		groupInvitationManager0
 				.sendInvitation(groupId0, c, text, timestamp, signature);
 	}

briar-core/src/test/java/org/briarproject/briar/privategroup/PrivateGroupManagerIntegrationTest.java

@@ -253,8 +253,7 @@ public class PrivateGroupManagerIntegrationTest
 		long inviteTime = joinTime;
 		Contact c1 = contactManager0.getContact(contactId1From0);
 		byte[] creatorSignature = groupInvitationFactory
-				.signInvitation(c1, privateGroup0.getId(), inviteTime,
-						author0.getPrivateKey());
+				.signInvitation(author0, c1, privateGroup0.getId(), inviteTime);
 		GroupMessage joinMsg1 = groupMessageFactory
 				.createJoinMessage(privateGroup0.getId(), joinTime, author1,
 						inviteTime, creatorSignature);
@@ -306,8 +305,7 @@ public class PrivateGroupManagerIntegrationTest
 		// signature uses joiner's key, not creator's key
 		Contact c1 = contactManager0.getContact(contactId1From0);
 		creatorSignature = groupInvitationFactory
-				.signInvitation(c1, privateGroup0.getId(), inviteTime,
-						author1.getPrivateKey());
+				.signInvitation(author1, c1, privateGroup0.getId(), inviteTime);
 		GroupMessage joinMsg1 = groupMessageFactory
 				.createJoinMessage(privateGroup0.getId(), joinTime, author1,
 						inviteTime, creatorSignature);
@@ -400,8 +398,7 @@ public class PrivateGroupManagerIntegrationTest
 		long inviteTime = joinTime - 1;
 		Contact c2 = contactManager0.getContact(contactId2From0);
 		byte[] creatorSignature = groupInvitationFactory
-				.signInvitation(c2, privateGroup0.getId(), inviteTime,
-						author0.getPrivateKey());
+				.signInvitation(author0, c2, privateGroup0.getId(), inviteTime);
 		GroupMessage joinMsg2 = groupMessageFactory
 				.createJoinMessage(privateGroup0.getId(), joinTime, author2,
 						inviteTime, creatorSignature);
@@ -522,8 +519,7 @@ public class PrivateGroupManagerIntegrationTest
 		long inviteTime = joinTime - 1;
 		Contact c1 = contactManager0.getContact(contactId1From0);
 		byte[] creatorSignature = groupInvitationFactory
-				.signInvitation(c1, privateGroup0.getId(), inviteTime,
-						author0.getPrivateKey());
+				.signInvitation(author0, c1, privateGroup0.getId(), inviteTime);
 		GroupMessage joinMsg1 = groupMessageFactory
 				.createJoinMessage(privateGroup0.getId(), joinTime, author1,
 						inviteTime, creatorSignature);

briar-core/src/test/java/org/briarproject/briar/privategroup/invitation/GroupInvitationIntegrationTest.java

@@ -176,9 +176,9 @@ public class GroupInvitationIntegrationTest
 		groupInvitationManager1
 				.respondToInvitation(contactId0From1, privateGroup0, true);
 
-		messages = db1.transactionWithResult(true,
-				txn -> groupInvitationManager1
-						.getMessageHeaders(txn, contactId0From1));
+		messages = db1.transactionWithResult(true, txn ->
+				groupInvitationManager1.getMessageHeaders(txn,
+						contactId0From1));
 		assertEquals(2, messages.size());
 		boolean foundResponse = false;
 		for (ConversationMessageHeader m : messages) {
@@ -199,9 +199,9 @@ public class GroupInvitationIntegrationTest
 
 		sync1To0(1, true);
 
-		messages = db1.transactionWithResult(true, txn ->
-				groupInvitationManager0
-						.getMessageHeaders(txn, contactId1From0));
+		messages = db0.transactionWithResult(true, txn ->
+				groupInvitationManager0.getMessageHeaders(txn,
+						contactId1From0));
 		assertEquals(2, messages.size());
 		foundResponse = false;
 		for (ConversationMessageHeader m : messages) {
@@ -228,13 +228,15 @@ public class GroupInvitationIntegrationTest
 		sendInvitation(timestamp, null);
 
 		// 0 has one read outgoing message
-		Group g1 = groupInvitationManager0.getContactGroup(contact1From0);
+		Group g1 = groupInvitationManager0.getContactGroup(contact1From0,
+				author0.getId());
 		assertGroupCount(messageTracker0, g1.getId(), 1, 0, timestamp);
 
 		sync0To1(1, true);
 
 		// 1 has one unread message
-		Group g0 = groupInvitationManager1.getContactGroup(contact0From1);
+		Group g0 = groupInvitationManager1.getContactGroup(contact0From1,
+				author1.getId());
 		assertGroupCount(messageTracker1, g0.getId(), 1, 1, timestamp);
 		ConversationMessageHeader m = db1.transactionWithResult(true, txn ->
 				groupInvitationManager1.getMessageHeaders(txn, contactId0From1)
@@ -460,8 +462,8 @@ public class GroupInvitationIntegrationTest
 
 	private void sendInvitation(long timestamp, @Nullable String text) throws
 			DbException {
-		byte[] signature = groupInvitationFactory.signInvitation(contact1From0,
-				privateGroup0.getId(), timestamp, author0.getPrivateKey());
+		byte[] signature = groupInvitationFactory.signInvitation(author0,
+				contact1From0, privateGroup0.getId(), timestamp);
 		groupInvitationManager0
 				.sendInvitation(privateGroup0.getId(), contactId1From0, text,
 						timestamp, signature);

briar-core/src/test/java/org/briarproject/briar/privategroup/invitation/GroupInvitationManagerImplTest.java

@@ -14,7 +14,8 @@ 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.identity.Author;
-import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.identity.IdentityManager;
+import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.sync.Group;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.Message;
@@ -49,6 +50,7 @@ import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
 import static org.briarproject.bramble.test.TestUtils.getAuthor;
 import static org.briarproject.bramble.test.TestUtils.getContact;
 import static org.briarproject.bramble.test.TestUtils.getGroup;
+import static org.briarproject.bramble.test.TestUtils.getLocalAuthor;
 import static org.briarproject.bramble.test.TestUtils.getMessage;
 import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
 import static org.briarproject.bramble.test.TestUtils.getRandomId;
@@ -70,6 +72,8 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 
 	private final DatabaseComponent db = context.mock(DatabaseComponent.class);
 	private final ClientHelper clientHelper = context.mock(ClientHelper.class);
+	private final IdentityManager identityManager =
+			context.mock(IdentityManager.class);
 	private final ClientVersioningManager clientVersioningManager =
 			context.mock(ClientVersioningManager.class);
 	private final ContactGroupFactory contactGroupFactory =
@@ -99,8 +103,8 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 
 	private final Transaction txn = new Transaction(null, false);
 	private final Author author = getAuthor();
-	private final Contact contact = getContact(author,
-			new AuthorId(getRandomId()), true);
+	private final Contact contact = getContact(author, true);
+	private final LocalAuthor localAuthor = getLocalAuthor();
 	private final ContactId contactId = contact.getId();
 	private final Group localGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
 	private final Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
@@ -143,9 +147,9 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 		MessageTracker messageTracker = context.mock(MessageTracker.class);
 		groupInvitationManager = new GroupInvitationManagerImpl(db,
 				clientHelper, clientVersioningManager, metadataParser,
-				messageTracker, contactGroupFactory, privateGroupFactory,
-				privateGroupManager, messageParser, sessionParser,
-				sessionEncoder, engineFactory);
+				messageTracker, identityManager, contactGroupFactory,
+				privateGroupFactory, privateGroupManager, messageParser,
+				sessionParser, sessionEncoder, engineFactory);
 	}
 
 	@Test
@@ -181,8 +185,10 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 				.of(new BdfEntry(GROUP_KEY_CONTACT_ID, c.getId().getInt()));
 
 		context.checking(new Expectations() {{
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, c);
+					MAJOR_VERSION, c, localAuthor.getId());
 			will(returnValue(contactGroup));
 			oneOf(db).addGroup(txn, contactGroup);
 			oneOf(clientVersioningManager).getClientVisibility(txn, contactId,
@@ -204,8 +210,10 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 
 	private void expectAddingMember(GroupId g, Contact c) throws Exception {
 		context.checking(new Expectations() {{
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, c);
+					MAJOR_VERSION, c, localAuthor.getId());
 			will(returnValue(contactGroup));
 		}});
 		expectGetSession(noResults, new SessionId(g.getBytes()),
@@ -260,8 +268,10 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 	@Test
 	public void testRemovingContact() throws Exception {
 		context.checking(new Expectations() {{
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, contact);
+					MAJOR_VERSION, contact, localAuthor.getId());
 			will(returnValue(contactGroup));
 			oneOf(db).removeGroup(txn, contactGroup);
 		}});
@@ -475,8 +485,10 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 			will(returnValue(txn));
 			oneOf(db).getContact(txn, contactId);
 			will(returnValue(contact));
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, contact);
+					MAJOR_VERSION, contact, localAuthor.getId());
 			will(returnValue(contactGroup));
 		}});
 		expectCreateStorageId();
@@ -507,8 +519,10 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 			will(returnValue(txn));
 			oneOf(db).getContact(txn, contactId);
 			will(returnValue(contact));
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, contact);
+					MAJOR_VERSION, contact, localAuthor.getId());
 			will(returnValue(contactGroup));
 			oneOf(sessionParser)
 					.parseCreatorSession(contactGroup.getId(), bdfSession);
@@ -536,8 +550,10 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 			will(returnValue(txn));
 			oneOf(db).getContact(txn, contactId);
 			will(returnValue(contact));
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, contact);
+					MAJOR_VERSION, contact, localAuthor.getId());
 			will(returnValue(contactGroup));
 			oneOf(db).endTransaction(txn);
 		}});
@@ -588,8 +604,10 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 			will(returnValue(txn));
 			oneOf(db).getContact(txn, contactId);
 			will(returnValue(contact));
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, contact);
+					MAJOR_VERSION, contact, localAuthor.getId());
 			will(returnValue(contactGroup));
 			oneOf(sessionParser)
 					.parseInviteeSession(contactGroup.getId(), bdfSession);
@@ -610,8 +628,10 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 			will(returnValue(txn));
 			oneOf(db).getContact(txn, contactId);
 			will(returnValue(contact));
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, contact);
+					MAJOR_VERSION, contact, localAuthor.getId());
 			will(returnValue(contactGroup));
 			oneOf(sessionParser)
 					.parsePeerSession(contactGroup.getId(), bdfSession);
@@ -635,8 +655,10 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 			will(returnValue(txn));
 			oneOf(db).getContact(txn, contactId);
 			will(returnValue(contact));
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, contact);
+					MAJOR_VERSION, contact, localAuthor.getId());
 			will(returnValue(contactGroup));
 			oneOf(db).endTransaction(txn);
 		}});
@@ -672,8 +694,10 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 		context.checking(new Expectations() {{
 			oneOf(db).getContact(txn, contactId);
 			will(returnValue(contact));
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, contact);
+					MAJOR_VERSION, contact, localAuthor.getId());
 			will(returnValue(contactGroup));
 			oneOf(messageParser).getMessagesVisibleInUiQuery();
 			will(returnValue(query));
@@ -744,10 +768,12 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 			will(returnValue(query));
 			oneOf(db).startTransaction(true);
 			will(returnValue(txn));
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
 			oneOf(db).getContacts(txn);
 			will(returnValue(Collections.singletonList(contact)));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, contact);
+					MAJOR_VERSION, contact, localAuthor.getId());
 			will(returnValue(contactGroup));
 			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
 					contactGroup.getId(), query);
@@ -814,8 +840,10 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 			throws Exception {
 		expectGetSession(oneResult, sessionId, contactGroup.getId());
 		context.checking(new Expectations() {{
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, contact);
+					MAJOR_VERSION, contact, localAuthor.getId());
 			will(returnValue(contactGroup));
 			oneOf(db).startTransaction(true);
 			will(returnValue(txn));
@@ -837,8 +865,10 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 	public void testAddingMember() throws Exception {
 		expectAddingMember(privateGroup.getId(), contact);
 		context.checking(new Expectations() {{
-			oneOf(db).getContactsByAuthorId(txn, author.getId());
-			will(returnValue(Collections.singletonList(contact)));
+			oneOf(db).containsContact(txn, author.getId());
+			will(returnValue(true));
+			oneOf(db).getContact(txn, author.getId());
+			will(returnValue(contact));
 		}});
 		groupInvitationManager.addingMember(txn, privateGroup.getId(), author);
 	}
@@ -866,16 +896,18 @@ public class GroupInvitationManagerImplTest extends BrambleMockTestCase {
 				sessionId, contactGroup3.getId());
 
 		context.checking(new Expectations() {{
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
 			oneOf(db).getContacts(txn);
 			will(returnValue(contacts));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, contact);
+					MAJOR_VERSION, contact, localAuthor.getId());
 			will(returnValue(contactGroup));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, contact2);
+					MAJOR_VERSION, contact2, localAuthor.getId());
 			will(returnValue(contactGroup2));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, contact3);
+					MAJOR_VERSION, contact3, localAuthor.getId());
 			will(returnValue(contactGroup3));
 			// session 1
 			oneOf(sessionParser).getRole(bdfSession);

briar-core/src/test/java/org/briarproject/briar/privategroup/invitation/InviteeProtocolEngineTest.java

@@ -330,8 +330,7 @@ public class InviteeProtocolEngineTest extends AbstractProtocolEngineTest {
 						privateGroup.getSalt(),
 						getRandomString(MAX_GROUP_INVITATION_TEXT_LENGTH),
 						signature);
-		Contact notCreatorContact = getContact(contactId, getAuthor(),
-				localAuthor.getId(), true);
+		Contact notCreatorContact = getContact(contactId, getAuthor(), true);
 
 		expectGetContactId();
 		context.checking(new Expectations() {{

briar-core/src/test/java/org/briarproject/briar/sharing/BlogSharingIntegrationTest.java

@@ -126,7 +126,7 @@ public class BlogSharingIntegrationTest
 
 		// get sharing group and assert group message count
 		GroupId g = contactGroupFactory.createContactGroup(CLIENT_ID,
-				MAJOR_VERSION, contact1From0).getId();
+				MAJOR_VERSION, contact1From0, author0.getId()).getId();
 		assertGroupCount(messageTracker0, g, 1, 0);
 
 		// check that request message state is correct
@@ -217,7 +217,7 @@ public class BlogSharingIntegrationTest
 
 		// get sharing group and assert group message count
 		GroupId g = contactGroupFactory.createContactGroup(CLIENT_ID,
-				MAJOR_VERSION, contact1From0).getId();
+				MAJOR_VERSION, contact1From0, author0.getId()).getId();
 		assertGroupCount(messageTracker0, g, 1, 0);
 
 		// sync first request message

briar-core/src/test/java/org/briarproject/briar/sharing/BlogSharingManagerImplTest.java

@@ -62,8 +62,7 @@ public class BlogSharingManagerImplTest extends BrambleMockTestCase {
 
 	private final LocalAuthor localAuthor = getLocalAuthor();
 	private final Author author = getAuthor();
-	private final Contact contact =
-			getContact(author, localAuthor.getId(), true);
+	private final Contact contact = getContact(author, true);
 	private final ContactId contactId = contact.getId();
 	private final Collection<Contact> contacts =
 			Collections.singletonList(contact);
@@ -123,8 +122,10 @@ public class BlogSharingManagerImplTest extends BrambleMockTestCase {
 
 		context.checking(new Expectations() {{
 			// Create the contact group and share it with the contact
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, contact);
+					MAJOR_VERSION, contact, localAuthor.getId());
 			will(returnValue(contactGroup));
 			oneOf(db).addGroup(txn, contactGroup);
 			oneOf(clientVersioningManager).getClientVisibility(txn, contactId,
@@ -202,7 +203,7 @@ public class BlogSharingManagerImplTest extends BrambleMockTestCase {
 		Message message = getMessage(contactGroup.getId());
 		context.checking(new Expectations() {{
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, contact);
+					MAJOR_VERSION, contact, localAuthor.getId());
 			will(returnValue(contactGroup));
 			oneOf(sessionParser)
 					.getSessionQuery(new SessionId(blog.getId().getBytes()));
@@ -237,10 +238,12 @@ public class BlogSharingManagerImplTest extends BrambleMockTestCase {
 		Session session = new Session(contactGroup.getId(), blog.getId());
 
 		context.checking(new Expectations() {{
+			oneOf(identityManager).getLocalAuthor(txn);
+			will(returnValue(localAuthor));
 			oneOf(db).getContacts(txn);
 			will(returnValue(contacts));
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
-					MAJOR_VERSION, contact);
+					MAJOR_VERSION, contact, localAuthor.getId());
 			will(returnValue(contactGroup));
 			oneOf(sessionParser)
 					.getSessionQuery(new SessionId(blog.getId().getBytes()));

briar-core/src/test/java/org/briarproject/briar/sharing/ForumSharingIntegrationTest.java

@@ -9,6 +9,7 @@ import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 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.test.TestDatabaseModule;
@@ -416,7 +417,7 @@ public class ForumSharingIntegrationTest
 
 		// response and invitation got tracked
 		Group group = contactGroupFactory.createContactGroup(CLIENT_ID,
-				MAJOR_VERSION, contact0From1);
+				MAJOR_VERSION, contact0From1, author1.getId());
 		assertEquals(2, c1.getMessageTracker().getGroupCount(group.getId())
 				.getMsgCount());
 
@@ -448,7 +449,7 @@ public class ForumSharingIntegrationTest
 
 		// assert that the invitation arrived
 		Group group = contactGroupFactory.createContactGroup(CLIENT_ID,
-				MAJOR_VERSION, contact0From1);
+				MAJOR_VERSION, contact0From1, author1.getId());
 		assertEquals(1, c1.getMessageTracker().getGroupCount(group.getId())
 				.getMsgCount());
 
@@ -777,8 +778,9 @@ public class ForumSharingIntegrationTest
 				.contains(contact0From1));
 
 		// send an accept message for the same forum
-		Message m = messageEncoder.encodeAcceptMessage(
-				forumSharingManager0.getContactGroup(contact1From0).getId(),
+		GroupId contactGroupId = forumSharingManager0.getContactGroup(
+				contact1From0, author0.getId()).getId();
+		Message m = messageEncoder.encodeAcceptMessage(contactGroupId,
 				forum0.getId(), clock.currentTimeMillis(), invitationId);
 		c0.getClientHelper().addLocalMessage(m, new BdfDictionary(), true);
 

briar-core/src/test/java/org/briarproject/briar/test/BriarIntegrationTest.java

@@ -283,21 +283,17 @@ public abstract class BriarIntegrationTest<C extends BriarIntegrationTestCompone
 	}
 
 	protected void addDefaultContacts() throws Exception {
-		contactId1From0 = contactManager0
-				.addContact(author1, author0.getId(), getSecretKey(),
-						clock.currentTimeMillis(), true, true, true);
+		contactId1From0 = contactManager0.addContact(author1, getSecretKey(),
+				clock.currentTimeMillis(), true, true, true);
 		contact1From0 = contactManager0.getContact(contactId1From0);
-		contactId0From1 = contactManager1
-				.addContact(author0, author1.getId(), getSecretKey(),
-						clock.currentTimeMillis(), true, true, true);
+		contactId0From1 = contactManager1.addContact(author0, getSecretKey(),
+				clock.currentTimeMillis(), true, true, true);
 		contact0From1 = contactManager1.getContact(contactId0From1);
-		contactId2From0 = contactManager0
-				.addContact(author2, author0.getId(), getSecretKey(),
-						clock.currentTimeMillis(), true, true, true);
+		contactId2From0 = contactManager0.addContact(author2, getSecretKey(),
+				clock.currentTimeMillis(), true, true, true);
 		contact2From0 = contactManager0.getContact(contactId2From0);
-		contactId0From2 = contactManager2
-				.addContact(author0, author2.getId(), getSecretKey(),
-						clock.currentTimeMillis(), true, true, true);
+		contactId0From2 = contactManager2.addContact(author0, getSecretKey(),
+				clock.currentTimeMillis(), true, true, true);
 		contact0From2 = contactManager2.getContact(contactId0From2);
 
 		// Sync initial client versioning updates
@@ -315,12 +311,10 @@ public abstract class BriarIntegrationTest<C extends BriarIntegrationTestCompone
 
 	protected void addContacts1And2(boolean haveTransportProperties)
 			throws Exception {
-		contactId2From1 = contactManager1
-				.addContact(author2, author1.getId(), getSecretKey(),
-						clock.currentTimeMillis(), true, true, true);
-		contactId1From2 = contactManager2
-				.addContact(author1, author2.getId(), getSecretKey(),
-						clock.currentTimeMillis(), true, true, true);
+		contactId2From1 = contactManager1.addContact(author2, getSecretKey(),
+				clock.currentTimeMillis(), true, true, true);
+		contactId1From2 = contactManager2.addContact(author1, getSecretKey(),
+				clock.currentTimeMillis(), true, true, true);
 
 		// Sync initial client versioning updates
 		sync1To2(1, true);