Add DB method for setting local handshake key pair.

bramble-core/src/main/java/org/briarproject/bramble/db/Database.java

@@ -685,6 +685,12 @@ interface Database<T> {
 	void setGroupVisibility(T txn, ContactId c, GroupId g, boolean shared)
 			throws DbException;
 
+	/**
+	 * Sets the handshake key pair for the local pseudonym with the given ID.
+	 */
+	void setHandshakeKeyPair(T txn, AuthorId local, byte[] publicKey,
+			byte[] privateKey) throws DbException;
+
 	/**
 	 * Marks the given message as shared.
 	 */

bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseComponentImpl.java

@@ -1035,6 +1035,16 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		}
 	}
 
+	@Override
+	public void setHandshakeKeyPair(Transaction transaction, AuthorId local,
+			byte[] publicKey, byte[] privateKey) throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsLocalAuthor(txn, local))
+			throw new NoSuchLocalAuthorException();
+		db.setHandshakeKeyPair(txn, local, publicKey, privateKey);
+	}
+
 	@Override
 	public void setReorderingWindow(Transaction transaction,
 			TransportKeySetId k, TransportId t, long timePeriod, long base,

bramble-core/src/main/java/org/briarproject/bramble/db/JdbcDatabase.java

@@ -1681,10 +1681,18 @@ abstract class JdbcDatabase implements Database<Connection> {
 			byte[] handshakePublicKey = rs.getBytes(5);
 			byte[] handshakePrivateKey = rs.getBytes(6);
 			long created = rs.getLong(7);
-			LocalAuthor localAuthor = new LocalAuthor(a, formatVersion, name,
-					publicKey, privateKey, handshakePublicKey,
-					handshakePrivateKey, created);
 			if (rs.next()) throw new DbStateException();
+			LocalAuthor localAuthor;
+			if (handshakePublicKey == null) {
+				if (handshakePrivateKey != null) throw new DbStateException();
+				localAuthor = new LocalAuthor(a, formatVersion, name,
+						publicKey, privateKey, created);
+			} else {
+				if (handshakePrivateKey == null) throw new DbStateException();
+				localAuthor = new LocalAuthor(a, formatVersion, name,
+						publicKey, privateKey, handshakePublicKey,
+						handshakePrivateKey, created);
+			}
 			rs.close();
 			ps.close();
 			return localAuthor;
@@ -3180,6 +3188,27 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	@Override
+	public void setHandshakeKeyPair(Connection txn, AuthorId local,
+			byte[] publicKey, byte[] privateKey) throws DbException {
+		PreparedStatement ps = null;
+		try {
+			String sql = "UPDATE localAuthors"
+					+ " SET handshakePublicKey = ?, handshakePrivateKey = ?"
+					+ " WHERE authorId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, publicKey);
+			ps.setBytes(2, privateKey);
+			ps.setBytes(3, local.getBytes());
+			int affected = ps.executeUpdate();
+			if (affected < 0 || affected > 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			tryToClose(ps, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	public void setMessageShared(Connection txn, MessageId m)
 			throws DbException {