diff --git a/briar-core/src/main/java/org/briarproject/briar/handshakekeyexchange/HandshakeKeyExchangeManagerImpl.java b/briar-core/src/main/java/org/briarproject/briar/handshakekeyexchange/HandshakeKeyExchangeManagerImpl.java
index 2d41e67d2..cd7bf4380 100644
--- a/briar-core/src/main/java/org/briarproject/briar/handshakekeyexchange/HandshakeKeyExchangeManagerImpl.java
+++ b/briar-core/src/main/java/org/briarproject/briar/handshakekeyexchange/HandshakeKeyExchangeManagerImpl.java
@@ -83,14 +83,21 @@ public class HandshakeKeyExchangeManagerImpl extends ConversationClientImpl
 
 	@Override
 	public void onDatabaseOpened(Transaction txn) throws DbException {
-		if (db.containsGroup(txn, localGroup.getId())) return;
-		db.addGroup(txn, localGroup);
-
 		// Get our own handshake public key
 		handshakePublicKey = identityManager.getHandshakeKeys(txn).getPublic();
 
-		// Set things up for any pre-existing contacts
-		for (Contact c : db.getContacts(txn)) addingContact(txn, c);
+		if (!db.containsGroup(txn, localGroup.getId())) {
+			db.addGroup(txn, localGroup);
+
+			// Set things up for any pre-existing contacts
+			for (Contact c : db.getContacts(txn)) addingContact(txn, c);
+		} else {
+			for (Contact c : db.getContacts(txn)) {
+				if (c.getHandshakePublicKey() == null) {
+					sendHandshakePublicKey(txn, c);
+				}
+			}
+		}
 	}
 
 	@Override
@@ -192,7 +199,7 @@ public class HandshakeKeyExchangeManagerImpl extends ConversationClientImpl
 
 	private void sendHandshakePublicKey(Transaction txn, Contact c)
 			throws DbException {
-		LOG.info("Sending our handshake public key to " + c.getAlias());
+		LOG.info("Sending our handshake public key to " + c.getAuthor().getName());
 		Group group = getContactGroup(c);
 		GroupId g = group.getId();
 		if (!db.containsGroup(txn, g)) db.addGroup(txn, group);
diff --git a/briar-core/src/main/java/org/briarproject/briar/handshakekeyexchange/HandshakeKeyExchangeModule.java b/briar-core/src/main/java/org/briarproject/briar/handshakekeyexchange/HandshakeKeyExchangeModule.java
index 925b80e7c..e1cb335f9 100644
--- a/briar-core/src/main/java/org/briarproject/briar/handshakekeyexchange/HandshakeKeyExchangeModule.java
+++ b/briar-core/src/main/java/org/briarproject/briar/handshakekeyexchange/HandshakeKeyExchangeModule.java
@@ -1,8 +1,11 @@
 package org.briarproject.briar.handshakekeyexchange;
 
+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.sync.validation.ValidationManager;
+import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.versioning.ClientVersioningManager;
 import org.briarproject.briar.api.conversation.ConversationManager;
 import org.briarproject.briar.api.handshakekeyexchange.HandshakeKeyExchangeManager;
@@ -18,6 +21,9 @@ public class HandshakeKeyExchangeModule {
 	public static class EagerSingletons {
 		@Inject
 		HandshakeKeyExchangeManager handshakeKeyExchangeManager;
+
+		@Inject
+		HandshakeKeyExchangeValidator handshakeKeyExchangeValidator;
 	}
 
 	@Provides
@@ -41,4 +47,18 @@ public class HandshakeKeyExchangeModule {
 		conversationManager.registerConversationClient(handshakeKeyExchangeManager);
 		return handshakeKeyExchangeManager;
 	}
+
+	@Provides
+	@Singleton
+	HandshakeKeyExchangeValidator handshakeKeyExchangeValidator(
+			ValidationManager validationManager,
+			ClientHelper clientHelper,
+			MetadataEncoder metadataEncoder,
+			Clock clock) {
+		HandshakeKeyExchangeValidator validator =
+				new HandshakeKeyExchangeValidator(clientHelper, metadataEncoder, clock);
+		validationManager.registerMessageValidator(HandshakeKeyExchangeManager.CLIENT_ID, HandshakeKeyExchangeManager.MAJOR_VERSION,
+				validator);
+		return validator;
+	}
 }
diff --git a/briar-core/src/main/java/org/briarproject/briar/handshakekeyexchange/HandshakeKeyExchangeValidator.java b/briar-core/src/main/java/org/briarproject/briar/handshakekeyexchange/HandshakeKeyExchangeValidator.java
index a030013a2..1a26694c7 100644
--- a/briar-core/src/main/java/org/briarproject/briar/handshakekeyexchange/HandshakeKeyExchangeValidator.java
+++ b/briar-core/src/main/java/org/briarproject/briar/handshakekeyexchange/HandshakeKeyExchangeValidator.java
@@ -4,12 +4,17 @@ 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.BdfEntry;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.data.MetadataEncoder;
 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 static org.briarproject.briar.handshakekeyexchange.HandshakeKeyExchangeConstants.MSG_KEY_LOCAL;
+
+import static org.briarproject.bramble.util.ValidationUtils.checkSize;
 
 import javax.inject.Inject;
 
@@ -26,6 +31,10 @@ public class HandshakeKeyExchangeValidator extends BdfMessageValidator {
 	@Override
 	protected BdfMessageContext validateMessage(Message m, Group g,
 			BdfList body) throws InvalidMessageException, FormatException {
-		return null;
+		checkSize(body,1);
+	    BdfDictionary meta = BdfDictionary.of(
+	       new BdfEntry(MSG_KEY_LOCAL, false)
+	    );
+		return new BdfMessageContext(meta);
 	}
 }