diff --git a/bramble-api/src/main/java/org/briarproject/bramble/api/db/DatabaseComponent.java b/bramble-api/src/main/java/org/briarproject/bramble/api/db/DatabaseComponent.java
index e5be04b55..563ce2d8e 100644
--- a/bramble-api/src/main/java/org/briarproject/bramble/api/db/DatabaseComponent.java
+++ b/bramble-api/src/main/java/org/briarproject/bramble/api/db/DatabaseComponent.java
@@ -2,6 +2,7 @@ package org.briarproject.bramble.api.db;
 
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.PendingContact;
 import org.briarproject.bramble.api.contact.PendingContactId;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.identity.Author;
@@ -137,6 +138,12 @@ public interface DatabaseComponent {
 	void addLocalMessage(Transaction txn, Message m, Metadata meta,
 			boolean shared) throws DbException;
 
+	/**
+	 * Stores a pending contact.
+	 */
+	void addPendingContact(Transaction txn, PendingContact p)
+			throws DbException;
+
 	/**
 	 * Stores a transport.
 	 */
@@ -153,21 +160,35 @@ public interface DatabaseComponent {
 	/**
 	 * Returns true if the database contains the given contact for the given
 	 * local pseudonym.
+	 * <p/>
+	 * Read-only.
 	 */
 	boolean containsContact(Transaction txn, AuthorId remote, AuthorId local)
 			throws DbException;
 
 	/**
 	 * Returns true if the database contains the given group.
+	 * <p/>
+	 * Read-only.
 	 */
 	boolean containsGroup(Transaction txn, GroupId g) throws DbException;
 
 	/**
 	 * Returns true if the database contains the given local author.
+	 * <p/>
+	 * Read-only.
 	 */
 	boolean containsLocalAuthor(Transaction txn, AuthorId local)
 			throws DbException;
 
+	/**
+	 * Returns true if the database contains the given pending contact.
+	 * <p/>
+	 * Read-only.
+	 */
+	boolean containsPendingContact(Transaction txn, PendingContactId p)
+			throws DbException;
+
 	/**
 	 * Deletes the message with the given ID. Unlike
 	 * {@link #removeMessage(Transaction, MessageId)}, the message ID,
@@ -292,8 +313,8 @@ public interface DatabaseComponent {
 	 * <p/>
 	 * Read-only.
 	 */
-	Collection<HandshakeKeySet> getHandshakeKeys(Transaction txn,
-			TransportId t) throws DbException;
+	Collection<HandshakeKeySet> getHandshakeKeys(Transaction txn, TransportId t)
+			throws DbException;
 
 	/**
 	 * Returns the local pseudonym with the given ID.
@@ -443,6 +464,14 @@ public interface DatabaseComponent {
 	 */
 	long getNextSendTime(Transaction txn, ContactId c) throws DbException;
 
+	/**
+	 * Returns all pending contacts.
+	 * <p/>
+	 * Read-only.
+	 */
+	Collection<PendingContact> getPendingContacts(Transaction txn)
+			throws DbException;
+
 	/**
 	 * Returns all settings in the given namespace.
 	 * <p/>
@@ -539,6 +568,12 @@ public interface DatabaseComponent {
 	 */
 	void removeMessage(Transaction txn, MessageId m) throws DbException;
 
+	/**
+	 * Removes a pending contact (and all associated state) from the database.
+	 */
+	void removePendingContact(Transaction txn, PendingContactId p)
+			throws DbException;
+
 	/**
 	 * Removes a transport (and all associated state) from the database.
 	 */
@@ -591,13 +626,21 @@ public interface DatabaseComponent {
 			Collection<MessageId> dependencies) throws DbException;
 
 	/**
-	 * Sets the reordering window for the given key set and transport in the
-	 * given time period.
+	 * Sets the reordering window for the given transport key set in the given
+	 * time period.
 	 */
 	void setReorderingWindow(Transaction txn, TransportKeySetId k,
 			TransportId t, long timePeriod, long base, byte[] bitmap)
 			throws DbException;
 
+	/**
+	 * Sets the reordering window for the given handshake key set in the given
+	 * time period.
+	 */
+	void setReorderingWindow(Transaction txn, HandshakeKeySetId k,
+			TransportId t, long timePeriod, long base, byte[] bitmap)
+			throws DbException;
+
 	/**
 	 * Marks the given transport keys as usable for outgoing streams.
 	 */
diff --git a/bramble-api/src/main/java/org/briarproject/bramble/api/db/NoSuchPendingContactException.java b/bramble-api/src/main/java/org/briarproject/bramble/api/db/NoSuchPendingContactException.java
new file mode 100644
index 000000000..d620e6d36
--- /dev/null
+++ b/bramble-api/src/main/java/org/briarproject/bramble/api/db/NoSuchPendingContactException.java
@@ -0,0 +1,9 @@
+package org.briarproject.bramble.api.db;
+
+/**
+ * Thrown when a database operation is attempted for a pending contact that is
+ * not in the database. This exception may occur due to concurrent updates and
+ * does not indicate a database error.
+ */
+public class NoSuchPendingContactException extends DbException {
+}
diff --git a/bramble-api/src/main/java/org/briarproject/bramble/api/db/PendingContactExistsException.java b/bramble-api/src/main/java/org/briarproject/bramble/api/db/PendingContactExistsException.java
new file mode 100644
index 000000000..cefca3f0a
--- /dev/null
+++ b/bramble-api/src/main/java/org/briarproject/bramble/api/db/PendingContactExistsException.java
@@ -0,0 +1,9 @@
+package org.briarproject.bramble.api.db;
+
+/**
+ * Thrown when a duplicate pending contact is added to the database. This
+ * exception may occur due to concurrent updates and does not indicate a
+ * database error.
+ */
+public class PendingContactExistsException extends DbException {
+}
diff --git a/bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseComponentImpl.java b/bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseComponentImpl.java
index a70d1ca6b..b92ab8660 100644
--- a/bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseComponentImpl.java
+++ b/bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseComponentImpl.java
@@ -2,6 +2,7 @@ package org.briarproject.bramble.db;
 
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.PendingContact;
 import org.briarproject.bramble.api.contact.PendingContactId;
 import org.briarproject.bramble.api.contact.event.ContactAddedEvent;
 import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
@@ -22,8 +23,10 @@ import org.briarproject.bramble.api.db.NoSuchContactException;
 import org.briarproject.bramble.api.db.NoSuchGroupException;
 import org.briarproject.bramble.api.db.NoSuchLocalAuthorException;
 import org.briarproject.bramble.api.db.NoSuchMessageException;
+import org.briarproject.bramble.api.db.NoSuchPendingContactException;
 import org.briarproject.bramble.api.db.NoSuchTransportException;
 import org.briarproject.bramble.api.db.NullableDbCallable;
+import org.briarproject.bramble.api.db.PendingContactExistsException;
 import org.briarproject.bramble.api.db.TaskAction;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.event.EventBus;
@@ -275,7 +278,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
 		if (!db.containsPendingContact(txn, p))
-			throw new NoSuchContactException();
+			throw new NoSuchPendingContactException();
 		if (!db.containsTransport(txn, k.getTransportId()))
 			throw new NoSuchTransportException();
 		return db.addHandshakeKeys(txn, p, k);
@@ -309,6 +312,16 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		db.mergeMessageMetadata(txn, m.getId(), meta);
 	}
 
+	@Override
+	public void addPendingContact(Transaction transaction, PendingContact p)
+			throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (db.containsPendingContact(txn, p.getId()))
+			throw new PendingContactExistsException();
+		db.addPendingContact(txn, p);
+	}
+
 	@Override
 	public void addTransport(Transaction transaction, TransportId t,
 			int maxLatency) throws DbException {
@@ -353,6 +366,13 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.containsLocalAuthor(txn, local);
 	}
 
+	@Override
+	public boolean containsPendingContact(Transaction transaction,
+			PendingContactId p) throws DbException {
+		T txn = unbox(transaction);
+		return db.containsPendingContact(txn, p);
+	}
+
 	@Override
 	public void deleteMessage(Transaction transaction, MessageId m)
 			throws DbException {
@@ -692,6 +712,13 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.getNextSendTime(txn, c);
 	}
 
+	@Override
+	public Collection<PendingContact> getPendingContacts(
+			Transaction transaction) throws DbException {
+		T txn = unbox(transaction);
+		return db.getPendingContacts(txn);
+	}
+
 	@Override
 	public Settings getSettings(Transaction transaction, String namespace)
 			throws DbException {
@@ -709,9 +736,13 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public void incrementStreamCounter(Transaction txn, TransportId t,
+	public void incrementStreamCounter(Transaction transaction, TransportId t,
 			HandshakeKeySetId k) throws DbException {
-		// TODO
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsTransport(txn, t))
+			throw new NoSuchTransportException();
+		db.incrementStreamCounter(txn, t, k);
 	}
 
 	@Override
@@ -897,6 +928,16 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		db.removeMessage(txn, m);
 	}
 
+	@Override
+	public void removePendingContact(Transaction transaction,
+			PendingContactId p) throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsPendingContact(txn, p))
+			throw new NoSuchPendingContactException();
+		db.removePendingContact(txn, p);
+	}
+
 	@Override
 	public void removeTransport(Transaction transaction, TransportId t)
 			throws DbException {
@@ -1018,6 +1059,17 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		db.setReorderingWindow(txn, k, t, timePeriod, base, bitmap);
 	}
 
+	@Override
+	public void setReorderingWindow(Transaction transaction,
+			HandshakeKeySetId k, TransportId t, long timePeriod, long base,
+			byte[] bitmap) throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsTransport(txn, t))
+			throw new NoSuchTransportException();
+		db.setReorderingWindow(txn, k, t, timePeriod, base, bitmap);
+	}
+
 	@Override
 	public void setTransportKeysActive(Transaction transaction, TransportId t,
 			TransportKeySetId k) throws DbException {