diff --git a/briar-api/src/main/java/org/briarproject/briar/api/conversation/ConversationManager.java b/briar-api/src/main/java/org/briarproject/briar/api/conversation/ConversationManager.java
index a5698375f..fb51b2574 100644
--- a/briar-api/src/main/java/org/briarproject/briar/api/conversation/ConversationManager.java
+++ b/briar-api/src/main/java/org/briarproject/briar/api/conversation/ConversationManager.java
@@ -24,7 +24,7 @@ public interface ConversationManager {
 
 	/**
 	 * Returns the headers of all messages in the given private conversation.
-	 *
+	 * <p>
 	 * Only {@link MessagingManager} returns only headers.
 	 * The others also return the message text.
 	 */
@@ -36,6 +36,13 @@ public interface ConversationManager {
 	 */
 	GroupCount getGroupCount(ContactId c) throws DbException;
 
+	/**
+	 * Deletes all messages exchanged with the given contact.
+	 *
+	 * @return true if all messages could be deleted, false otherwise
+	 */
+	boolean deleteAllMessages(ContactId c) throws DbException;
+
 	@NotNullByDefault
 	interface ConversationClient {
 
@@ -49,6 +56,14 @@ public interface ConversationManager {
 
 		void setReadFlag(GroupId g, MessageId m, boolean read)
 				throws DbException;
+
+		/**
+		 * Deletes all messages associated with the given contact.
+		 *
+		 * @return true if all messages could be deleted, false otherwise
+		 */
+		boolean deleteAllMessages(Transaction txn,
+				ContactId c) throws DbException;
 	}
 
 }
diff --git a/briar-core/src/main/java/org/briarproject/briar/introduction/IntroductionManagerImpl.java b/briar-core/src/main/java/org/briarproject/briar/introduction/IntroductionManagerImpl.java
index 0b5afe9df..185c59c0b 100644
--- a/briar-core/src/main/java/org/briarproject/briar/introduction/IntroductionManagerImpl.java
+++ b/briar-core/src/main/java/org/briarproject/briar/introduction/IntroductionManagerImpl.java
@@ -45,6 +45,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.Set;
 
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
@@ -557,6 +558,26 @@ class IntroductionManagerImpl extends ConversationClientImpl
 		}
 	}
 
+	@Override
+	public boolean deleteAllMessages(Transaction txn, ContactId c)
+			throws DbException {
+		// TODO actually delete messages (#1627 and #1629)
+		return getMessageIds(txn, c).size() == 0;
+	}
+
+	private Set<MessageId> getMessageIds(Transaction txn, ContactId c)
+			throws DbException {
+		GroupId g = getContactGroup(db.getContact(txn, c)).getId();
+		BdfDictionary query = messageParser.getMessagesVisibleInUiQuery();
+		try {
+			Map<MessageId, BdfDictionary> results =
+					clientHelper.getMessageMetadataAsDictionary(txn, g, query);
+			return results.keySet();
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
 	private static class StoredSession {
 
 		private final MessageId storageId;
diff --git a/briar-core/src/main/java/org/briarproject/briar/messaging/ConversationManagerImpl.java b/briar-core/src/main/java/org/briarproject/briar/messaging/ConversationManagerImpl.java
index 7d0d04a9d..957f7e2ad 100644
--- a/briar-core/src/main/java/org/briarproject/briar/messaging/ConversationManagerImpl.java
+++ b/briar-core/src/main/java/org/briarproject/briar/messaging/ConversationManagerImpl.java
@@ -73,4 +73,15 @@ class ConversationManagerImpl implements ConversationManager {
 		return new GroupCount(msgCount, unreadCount, latestTime);
 	}
 
+	@Override
+	public boolean deleteAllMessages(ContactId c) throws DbException {
+		return db.transactionWithResult(false, txn -> {
+			boolean allDeleted = true;
+			for (ConversationClient client : clients) {
+				allDeleted = client.deleteAllMessages(txn, c) && allDeleted;
+			}
+			return allDeleted;
+		});
+	}
+
 }
diff --git a/briar-core/src/main/java/org/briarproject/briar/messaging/MessagingManagerImpl.java b/briar-core/src/main/java/org/briarproject/briar/messaging/MessagingManagerImpl.java
index c85a2a22d..cd6cbbd3e 100644
--- a/briar-core/src/main/java/org/briarproject/briar/messaging/MessagingManagerImpl.java
+++ b/briar-core/src/main/java/org/briarproject/briar/messaging/MessagingManagerImpl.java
@@ -404,4 +404,17 @@ class MessagingManagerImpl implements MessagingManager, IncomingMessageHook,
 		return minorVersion > 0;
 	}
 
+	@Override
+	public boolean deleteAllMessages(Transaction txn, ContactId c)
+			throws DbException {
+		GroupId g = getContactGroup(db.getContact(txn, c)).getId();
+		// this indiscriminately deletes all raw messages in this group
+		// also attachments
+		for (MessageId messageId : db.getMessageIds(txn, g)) {
+			db.deleteMessage(txn, messageId);
+			db.deleteMessageMetadata(txn, messageId);
+		}
+		return true;
+	}
+
 }
diff --git a/briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/GroupInvitationManagerImpl.java b/briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/GroupInvitationManagerImpl.java
index e72bc3af9..b2d80c7bb 100644
--- a/briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/GroupInvitationManagerImpl.java
+++ b/briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/GroupInvitationManagerImpl.java
@@ -43,6 +43,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.Set;
 
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
@@ -629,6 +630,26 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 		return m;
 	}
 
+	@Override
+	public boolean deleteAllMessages(Transaction txn, ContactId c)
+			throws DbException {
+		// TODO actually delete messages (#1627 and #1629)
+		return getMessageIds(txn, c).size() == 0;
+	}
+
+	private Set<MessageId> getMessageIds(Transaction txn, ContactId c)
+			throws DbException {
+		GroupId g = getContactGroup(db.getContact(txn, c)).getId();
+		BdfDictionary query = messageParser.getMessagesVisibleInUiQuery();
+		try {
+			Map<MessageId, BdfDictionary> results =
+					clientHelper.getMessageMetadataAsDictionary(txn, g, query);
+			return results.keySet();
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
 	private static class StoredSession {
 
 		private final MessageId storageId;
diff --git a/briar-core/src/main/java/org/briarproject/briar/sharing/SharingManagerImpl.java b/briar-core/src/main/java/org/briarproject/briar/sharing/SharingManagerImpl.java
index 2ac7dd8d1..194bdb41f 100644
--- a/briar-core/src/main/java/org/briarproject/briar/sharing/SharingManagerImpl.java
+++ b/briar-core/src/main/java/org/briarproject/briar/sharing/SharingManagerImpl.java
@@ -40,6 +40,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.Set;
 
 import javax.annotation.Nullable;
 
@@ -537,6 +538,26 @@ abstract class SharingManagerImpl<S extends Shareable>
 		return m;
 	}
 
+	@Override
+	public boolean deleteAllMessages(Transaction txn, ContactId c)
+			throws DbException {
+		// TODO actually delete messages (#1627 and #1629)
+		return getMessageIds(txn, c).size() == 0;
+	}
+
+	private Set<MessageId> getMessageIds(Transaction txn, ContactId c)
+			throws DbException {
+		GroupId g = getContactGroup(db.getContact(txn, c)).getId();
+		BdfDictionary query = messageParser.getMessagesVisibleInUiQuery();
+		try {
+			Map<MessageId, BdfDictionary> results =
+					clientHelper.getMessageMetadataAsDictionary(txn, g, query);
+			return results.keySet();
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
 	private static class StoredSession {
 
 		private final MessageId storageId;