Refactor KeyManager and TagRecogniser. #55

briar-api/src/org/briarproject/api/android/AndroidNotificationManager.java

@@ -1,13 +1,14 @@
 package org.briarproject.api.android;
 
 import org.briarproject.api.ContactId;
+import org.briarproject.api.lifecycle.Service;
 import org.briarproject.api.messaging.GroupId;
 
 /**
  * Manages notifications for private messages and group posts. All methods must
  * be called from the Android UI thread.
  */
-public interface AndroidNotificationManager {
+public interface AndroidNotificationManager extends Service {
 
 	public void showPrivateMessageNotification(ContactId c);
 

briar-api/src/org/briarproject/api/crypto/CryptoComponent.java

@@ -1,5 +1,8 @@
 package org.briarproject.api.crypto;
 
+import org.briarproject.api.TransportId;
+import org.briarproject.api.transport.TransportKeys;
+
 import java.security.GeneralSecurityException;
 import java.security.SecureRandom;
 
@@ -26,56 +29,50 @@ public interface CryptoComponent {
 	/** Generates a random invitation code. */
 	int generateInvitationCode();
 
-	/**
-	 * Derives two confirmation codes from the given master secret. The first
-	 * code is for Alice to give to Bob; the second is for Bob to give to
-	 * Alice.
-	 */
-	int[] deriveConfirmationCodes(byte[] secret);
-
-	/**
-	 * Derives two nonces from the given master secret. The first nonce is for
-	 * Alice to sign; the second is for Bob to sign.
-	 */
-	byte[][] deriveInvitationNonces(byte[] secret);
-
 	/**
 	 * Derives a shared master secret from two public keys and one of the
 	 * corresponding private keys.
-	 * @param alice indicates whether the private key belongs to Alice or Bob.
+	 * @param alice whether the private key belongs to Alice or Bob.
 	 */
-	byte[] deriveMasterSecret(byte[] theirPublicKey, KeyPair ourKeyPair,
+	SecretKey deriveMasterSecret(byte[] theirPublicKey, KeyPair ourKeyPair,
 			boolean alice) throws GeneralSecurityException;
 
-	/** Derives a group salt from the given master secret. */
-	byte[] deriveGroupSalt(byte[] secret);
+	/**
+	 * Derives a confirmation code from the given master secret.
+	 * @param alice whether the code is for use by Alice or Bob.
+	 */
+	int deriveConfirmationCode(SecretKey master, boolean alice);
 
 	/**
-	 * Derives an initial secret for the given transport from the given master
+	 * Derives a header key for an invitation stream from the given master
 	 * secret.
+	 * @param alice whether the key is for use by Alice or Bob.
 	 */
-	byte[] deriveInitialSecret(byte[] secret, int transportIndex);
+	SecretKey deriveInvitationKey(SecretKey master, boolean alice);
 
 	/**
-	 * Derives a temporary secret for the given period from the given secret,
-	 * which is either the initial shared secret or the previous period's
-	 * temporary secret.
+	 * Derives a nonce from the given master secret for one of the parties to
+	 * sign.
+	 * @param alice whether the nonce is for use by Alice or Bob.
 	 */
-	byte[] deriveNextSecret(byte[] secret, long period);
+	byte[] deriveSignatureNonce(SecretKey master, boolean alice);
+
+	/** Derives a group salt from the given master secret. */
+	byte[] deriveGroupSalt(SecretKey master);
 
 	/**
-	 * Derives a tag key from the given temporary secret.
-	 * @param alice indicates whether the key is for streams initiated by
-	 * Alice or Bob.
+	 * Derives initial transport keys for the given transport in the given
+	 * rotation period from the given master secret.
+	 * @param alice whether the keys are for use by Alice or Bob.
 	 */
-	SecretKey deriveTagKey(byte[] secret, boolean alice);
+	TransportKeys deriveTransportKeys(TransportId t, SecretKey master,
+			long rotationPeriod, boolean alice);
 
 	/**
-	 * Derives a frame key from the given temporary secret and stream number.
-	 * @param alice indicates whether the key is for a stream initiated by
-	 * Alice or Bob.
+	 * Rotates the given transport keys to the given rotation period. If the
+	 * keys are for a future rotation period they are not rotated.
 	 */
-	SecretKey deriveFrameKey(byte[] secret, long streamNumber, boolean alice);
+	TransportKeys rotateTransportKeys(TransportKeys k, long rotationPeriod);
 
 	/** Encodes the pseudo-random tag that is used to recognise a stream. */
 	void encodeTag(byte[] tag, SecretKey tagKey, long streamNumber);

briar-api/src/org/briarproject/api/crypto/KeyManager.java

@@ -1,21 +0,0 @@
-package org.briarproject.api.crypto;
-
-import org.briarproject.api.ContactId;
-import org.briarproject.api.TransportId;
-import org.briarproject.api.lifecycle.Service;
-import org.briarproject.api.transport.Endpoint;
-import org.briarproject.api.transport.StreamContext;
-
-public interface KeyManager extends Service {
-
-	/**
-	 * Returns a {@link org.briarproject.api.transport.StreamContext
-	 * StreamContext} for sending data to the given contact over the given
-	 * transport, or null if an error occurs or the contact does not support
-	 * the transport.
-	 */
-	StreamContext getStreamContext(ContactId c, TransportId t);
-
-	/** Called whenever an endpoint has been added. */
-	void endpointAdded(Endpoint ep, int maxLatency, byte[] initialSecret);
-}

briar-api/src/org/briarproject/api/crypto/StreamDecrypterFactory.java

@@ -13,5 +13,5 @@ public interface StreamDecrypterFactory {
 	 * Creates a {@link StreamDecrypter} for decrypting an invitation stream.
 	 */
 	StreamDecrypter createInvitationStreamDecrypter(InputStream in,
-			byte[] secret, boolean alice);
+			SecretKey headerKey);
 }

briar-api/src/org/briarproject/api/crypto/StreamEncrypterFactory.java

@@ -13,5 +13,5 @@ public interface StreamEncrypterFactory {
 	 * Creates a {@link StreamEncrypter} for encrypting an invitation stream.
 	 */
 	StreamEncrypter createInvitationStreamEncrypter(OutputStream out,
-			byte[] secret, boolean alice);
+			SecretKey headerKey);
 }

briar-api/src/org/briarproject/api/db/DatabaseComponent.java

@@ -1,9 +1,5 @@
 package org.briarproject.api.db;
 
-import java.io.IOException;
-import java.util.Collection;
-import java.util.Map;
-
 import org.briarproject.api.Author;
 import org.briarproject.api.AuthorId;
 import org.briarproject.api.Contact;
@@ -26,8 +22,11 @@ import org.briarproject.api.messaging.SubscriptionAck;
 import org.briarproject.api.messaging.SubscriptionUpdate;
 import org.briarproject.api.messaging.TransportAck;
 import org.briarproject.api.messaging.TransportUpdate;
-import org.briarproject.api.transport.Endpoint;
-import org.briarproject.api.transport.TemporarySecret;
+import org.briarproject.api.transport.TransportKeys;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.Map;
 
 /**
  * Encapsulates the database implementation and exposes high-level operations
@@ -47,9 +46,6 @@ public interface DatabaseComponent {
 	 */
 	ContactId addContact(Author remote, AuthorId local) throws DbException;
 
-	/** Stores an endpoint. */
-	void addEndpoint(Endpoint ep) throws DbException;
-
 	/**
 	 * Subscribes to a group, or returns false if the user already has the
 	 * maximum number of public subscriptions.
@@ -62,18 +58,17 @@ public interface DatabaseComponent {
 	/** Stores a local message. */
 	void addLocalMessage(Message m) throws DbException;
 
-	/**
-	 * Stores the given temporary secrets and deletes any secrets that have
-	 * been made obsolete.
-	 */
-	void addSecrets(Collection<TemporarySecret> secrets) throws DbException;
-
 	/**
 	 * Stores a transport and returns true if the transport was not previously
 	 * in the database.
 	 */
 	boolean addTransport(TransportId t, int maxLatency) throws DbException;
 
+	/**
+	 * Stores the given transport keys for a newly added contact.
+	 */
+	void addTransportKeys(ContactId c, TransportKeys k) throws DbException;
+
 	/**
 	 * Returns an acknowledgement for the given contact, or null if there are
 	 * no messages to acknowledge.
@@ -214,16 +209,17 @@ public interface DatabaseComponent {
 	Map<ContactId, TransportProperties> getRemoteProperties(TransportId t)
 			throws DbException;
 
-	/** Returns all temporary secrets. */
-	Collection<TemporarySecret> getSecrets() throws DbException;
-
 	/** Returns all settings. */
 	Settings getSettings() throws DbException;
 
 	/** Returns all contacts who subscribe to the given group. */
 	Collection<Contact> getSubscribers(GroupId g) throws DbException;
 
-	/** Returns the maximum latencies of all supported transports. */
+	/** Returns all transport keys for the given transport. */
+	Map<ContactId, TransportKeys> getTransportKeys(TransportId t)
+			throws DbException;
+
+	/** Returns the maximum latencies in milliseconds of all transports. */
 	Map<TransportId, Integer> getTransportLatencies() throws DbException;
 
 	/** Returns the number of unread messages in each subscribed group. */
@@ -233,11 +229,10 @@ public interface DatabaseComponent {
 	Collection<ContactId> getVisibility(GroupId g) throws DbException;
 
 	/**
-	 * Increments the outgoing stream counter for the given endpoint in the
-	 * given rotation period and returns the old value, or -1 if the counter
-	 * does not exist.
+	 * Increments the outgoing stream counter for the given contact and
+	 * transport in the given rotation period .
 	 */
-	long incrementStreamCounter(ContactId c, TransportId t, long period)
+	void incrementStreamCounter(ContactId c, TransportId t, long rotationPeriod)
 			throws DbException;
 
 	/**
@@ -310,18 +305,11 @@ public interface DatabaseComponent {
 	 */
 	void removeTransport(TransportId t) throws DbException;
 
-	/**
-	 * Sets the reordering window for the given endpoint in the given rotation
-	 * period.
-	 */
-	void setReorderingWindow(ContactId c, TransportId t, long period,
-			long centre, byte[] bitmap) throws DbException;
-
 	/**
 	 * Makes a group visible to the given contact, adds it to the contact's
 	 * subscriptions, and sets it as the inbox group for the contact.
 	 */
-	public void setInboxGroup(ContactId c, Group g) throws DbException;
+	void setInboxGroup(ContactId c, Group g) throws DbException;
 
 	/**
 	 * Marks a message as read or unread.
@@ -335,6 +323,13 @@ public interface DatabaseComponent {
 	void setRemoteProperties(ContactId c,
 			Map<TransportId, TransportProperties> p) throws DbException;
 
+	/**
+	 * Sets the reordering window for the given contact and transport in the
+	 * given rotation period.
+	 */
+	void setReorderingWindow(ContactId c, TransportId t, long rotationPeriod,
+			long base, byte[] bitmap) throws DbException;
+
 	/**
 	 * Makes a group visible to the given set of contacts and invisible to any
 	 * other current or future contacts.
@@ -347,4 +342,10 @@ public interface DatabaseComponent {
 	 * to future contacts.
 	 */
 	void setVisibleToAll(GroupId g, boolean all) throws DbException;
+
+	/**
+	 * Stores the given transport keys, deleting any keys they have replaced.
+	 */
+	void updateTransportKeys(Map<ContactId, TransportKeys> keys)
+			throws DbException;
 }

briar-api/src/org/briarproject/api/messaging/Message.java

@@ -28,7 +28,7 @@ public interface Message {
 	/** Returns the message's content type. */
 	String getContentType();
 
-	/** Returns the message's timestamp. */
+	/** Returns the message's timestamp in milliseconds since the Unix epoch. */
 	long getTimestamp();
 
 	/** Returns the serialised message. */

briar-api/src/org/briarproject/api/transport/Endpoint.java

@@ -1,36 +0,0 @@
-package org.briarproject.api.transport;
-
-import org.briarproject.api.ContactId;
-import org.briarproject.api.TransportId;
-
-public class Endpoint {
-
-	protected final ContactId contactId;
-	protected final TransportId transportId;
-	private final long epoch;
-	private final boolean alice;
-
-	public Endpoint(ContactId contactId, TransportId transportId, long epoch,
-			boolean alice) {
-		this.contactId = contactId;
-		this.transportId = transportId;
-		this.epoch = epoch;
-		this.alice = alice;
-	}
-
-	public ContactId getContactId() {
-		return contactId;
-	}
-
-	public TransportId getTransportId() {
-		return transportId;
-	}
-
-	public long getEpoch() {
-		return epoch;
-	}
-
-	public boolean getAlice() {
-		return alice;
-	}
-}

briar-api/src/org/briarproject/api/transport/IncomingKeys.java

@@ -0,0 +1,51 @@
+package org.briarproject.api.transport;
+
+import org.briarproject.api.crypto.SecretKey;
+
+import static org.briarproject.api.transport.TransportConstants.REORDERING_WINDOW_SIZE;
+
+/**
+ * Contains transport keys for receiving streams from a given contact over a
+ * given transport in a given rotation period.
+ */
+public class IncomingKeys {
+
+	private final SecretKey tagKey, headerKey;
+	private final long rotationPeriod, windowBase;
+	private final byte[] windowBitmap;
+
+	public IncomingKeys(SecretKey tagKey, SecretKey headerKey,
+			long rotationPeriod) {
+		this(tagKey, headerKey, rotationPeriod, 0,
+				new byte[REORDERING_WINDOW_SIZE / 8]);
+	}
+
+	public IncomingKeys(SecretKey tagKey, SecretKey headerKey,
+			long rotationPeriod, long windowBase, byte[] windowBitmap) {
+		this.tagKey = tagKey;
+		this.headerKey = headerKey;
+		this.rotationPeriod = rotationPeriod;
+		this.windowBase = windowBase;
+		this.windowBitmap = windowBitmap;
+	}
+
+	public SecretKey getTagKey() {
+		return tagKey;
+	}
+
+	public SecretKey getHeaderKey() {
+		return headerKey;
+	}
+
+	public long getRotationPeriod() {
+		return rotationPeriod;
+	}
+
+	public long getWindowBase() {
+		return windowBase;
+	}
+
+	public byte[] getWindowBitmap() {
+		return windowBitmap;
+	}
+}

briar-api/src/org/briarproject/api/transport/KeyManager.java

@@ -0,0 +1,36 @@
+package org.briarproject.api.transport;
+
+import org.briarproject.api.ContactId;
+import org.briarproject.api.TransportId;
+import org.briarproject.api.db.DbException;
+import org.briarproject.api.lifecycle.Service;
+
+import java.util.Collection;
+
+/**
+ * Responsible for managing transport keys and recognising the pseudo-random
+ * tags of incoming streams.
+ */
+public interface KeyManager extends Service {
+
+	/**
+	 * Informs the key manager that a new contact has been added.
+	 * {@link StreamContext StreamContexts} for the contact can be created
+	 * after this method has returned.
+	 */
+	void contactAdded(ContactId c, Collection<TransportKeys> keys);
+
+	/**
+	 * Returns a {@link StreamContext} for sending a stream to the given
+	 * contact over the given transport, or null if an error occurs or the
+	 * contact does not support the transport.
+	 */
+	StreamContext getStreamContext(ContactId c, TransportId t);
+
+	/**
+	 * Looks up the given tag and returns a {@link StreamContext} for reading
+	 * from the corresponding stream if the tag was expected, or null if the
+	 * tag was unexpected.
+	 */
+	StreamContext recogniseTag(TransportId t, byte[] tag) throws DbException;
+}

briar-api/src/org/briarproject/api/transport/OutgoingKeys.java

@@ -0,0 +1,42 @@
+package org.briarproject.api.transport;
+
+import org.briarproject.api.crypto.SecretKey;
+
+/**
+ * Contains transport keys for sending streams to a given contact over a given
+ * transport in a given rotation period.
+ */
+public class OutgoingKeys {
+
+	private final SecretKey tagKey, headerKey;
+	private final long rotationPeriod, streamCounter;
+
+	public OutgoingKeys(SecretKey tagKey, SecretKey headerKey,
+			long rotationPeriod) {
+		this(tagKey, headerKey, rotationPeriod, 0);
+	}
+
+	public OutgoingKeys(SecretKey tagKey, SecretKey headerKey,
+			long rotationPeriod, long streamCounter) {
+		this.tagKey = tagKey;
+		this.headerKey = headerKey;
+		this.rotationPeriod = rotationPeriod;
+		this.streamCounter = streamCounter;
+	}
+
+	public SecretKey getTagKey() {
+		return tagKey;
+	}
+
+	public SecretKey getHeaderKey() {
+		return headerKey;
+	}
+
+	public long getRotationPeriod() {
+		return rotationPeriod;
+	}
+
+	public long getStreamCounter() {
+		return streamCounter;
+	}
+}

briar-api/src/org/briarproject/api/transport/StreamContext.java

@@ -2,22 +2,22 @@ package org.briarproject.api.transport;
 
 import org.briarproject.api.ContactId;
 import org.briarproject.api.TransportId;
+import org.briarproject.api.crypto.SecretKey;
 
 public class StreamContext {
 
 	private final ContactId contactId;
 	private final TransportId transportId;
-	private final byte[] secret;
+	private final SecretKey tagKey, headerKey;
 	private final long streamNumber;
-	private final boolean alice;
 
 	public StreamContext(ContactId contactId, TransportId transportId,
-			byte[] secret, long streamNumber, boolean alice) {
+			SecretKey tagKey, SecretKey headerKey, long streamNumber) {
 		this.contactId = contactId;
 		this.transportId = transportId;
-		this.secret = secret;
+		this.tagKey = tagKey;
+		this.headerKey = headerKey;
 		this.streamNumber = streamNumber;
-		this.alice = alice;
 	}
 
 	public ContactId getContactId() {
@@ -28,15 +28,15 @@ public class StreamContext {
 		return transportId;
 	}
 
-	public byte[] getSecret() {
-		return secret;
+	public SecretKey getTagKey() {
+		return tagKey;
+	}
+
+	public SecretKey getHeaderKey() {
+		return headerKey;
 	}
 
 	public long getStreamNumber() {
 		return streamNumber;
 	}
-
-	public boolean getAlice() {
-		return alice;
-	}
 }

briar-api/src/org/briarproject/api/transport/StreamReaderFactory.java

@@ -2,6 +2,8 @@ package org.briarproject.api.transport;
 
 import java.io.InputStream;
 
+import org.briarproject.api.crypto.SecretKey;
+
 public interface StreamReaderFactory {
 
 	/**
@@ -15,5 +17,5 @@ public interface StreamReaderFactory {
 	 * invitation stream.
 	 */
 	InputStream createInvitationStreamReader(InputStream in,
-			byte[] secret, boolean alice);
+			SecretKey headerKey);
 }

briar-api/src/org/briarproject/api/transport/StreamWriterFactory.java

@@ -2,6 +2,8 @@ package org.briarproject.api.transport;
 
 import java.io.OutputStream;
 
+import org.briarproject.api.crypto.SecretKey;
+
 public interface StreamWriterFactory {
 
 	/**
@@ -15,5 +17,5 @@ public interface StreamWriterFactory {
 	 * invitation stream.
 	 */
 	OutputStream createInvitationStreamWriter(OutputStream out,
-			byte[] secret, boolean alice);
+			SecretKey headerKey);
 }

briar-api/src/org/briarproject/api/transport/TagRecogniser.java

@@ -1,26 +0,0 @@
-package org.briarproject.api.transport;
-
-import org.briarproject.api.ContactId;
-import org.briarproject.api.TransportId;
-import org.briarproject.api.db.DbException;
-
-/** Keeps track of expected tags and uses them to recognise incoming streams. */
-public interface TagRecogniser {
-
-	/**
-	 * Looks up the given tag and returns a {@link StreamContext} for reading
-	 * from the stream if the tag was expected, or null if the tag was
-	 * unexpected.
-	 */
-	StreamContext recogniseTag(TransportId t, byte[] tag) throws DbException;
-
-	void addSecret(TemporarySecret s);
-
-	void removeSecret(ContactId c, TransportId t, long period);
-
-	void removeSecrets(ContactId c);
-
-	void removeSecrets(TransportId t);
-
-	void removeSecrets();
-}

briar-api/src/org/briarproject/api/transport/TemporarySecret.java

@@ -1,73 +0,0 @@
-package org.briarproject.api.transport;
-
-import static org.briarproject.api.transport.TransportConstants.REORDERING_WINDOW_SIZE;
-
-import org.briarproject.api.ContactId;
-import org.briarproject.api.TransportId;
-
-public class TemporarySecret extends Endpoint {
-
-	private final long period, outgoing, centre;
-	private final byte[] secret, bitmap;
-
-	/** Creates a temporary secret with the given reordering window. */
-	public TemporarySecret(ContactId contactId, TransportId transportId,
-			long epoch, boolean alice, long period, byte[] secret,
-			long outgoing, long centre, byte[] bitmap) {
-		super(contactId, transportId, epoch, alice);
-		this.period = period;
-		this.secret = secret;
-		this.outgoing = outgoing;
-		this.centre = centre;
-		this.bitmap = bitmap;
-	}
-
-	/** Creates a temporary secret with a new reordering window. */
-	public TemporarySecret(ContactId contactId, TransportId transportId,
-			long epoch, boolean alice, long period, byte[] secret) {
-		this(contactId, transportId, epoch, alice, period, secret, 0, 0,
-				new byte[REORDERING_WINDOW_SIZE / 8]);
-	}
-
-	/** Creates a temporary secret derived from the given endpoint. */
-	public TemporarySecret(Endpoint ep, long period, byte[] secret) {
-		this(ep.getContactId(), ep.getTransportId(), ep.getEpoch(),
-				ep.getAlice(), period, secret);
-	}
-
-	public long getPeriod() {
-		return period;
-	}
-
-	public byte[] getSecret() {
-		return secret;
-	}
-
-	public long getOutgoingStreamCounter() {
-		return outgoing;
-	}
-
-	public long getWindowCentre() {
-		return centre;
-	}
-
-	public byte[] getWindowBitmap() {
-		return bitmap;
-	}
-
-	@Override
-	public int hashCode() {
-		int periodHashCode = (int) (period ^ (period >>> 32));
-		return contactId.hashCode() ^ transportId.hashCode() ^ periodHashCode;
-	}
-
-	@Override
-	public boolean equals(Object o) {
-		if (o instanceof TemporarySecret) {
-			TemporarySecret s = (TemporarySecret) o;
-			return contactId.equals(s.contactId) &&
-					transportId.equals(s.transportId) && period == s.period;
-		}
-		return false;
-	}
-}

briar-api/src/org/briarproject/api/transport/TransportConstants.java

@@ -28,8 +28,8 @@ public interface TransportConstants {
 	 */
 	int MIN_STREAM_LENGTH = 64 * 1024; // 64 KiB
 
-	/** The maximum difference between two communicating devices' clocks. */
-	int MAX_CLOCK_DIFFERENCE = 60 * 60 * 1000; // 1 hour
+	/** The maximum difference in milliseconds between two peers' clocks. */
+	int MAX_CLOCK_DIFFERENCE = 24 * 60 * 60 * 1000; // 24 hours
 
 	/** The size of the reordering window. */
 	int REORDERING_WINDOW_SIZE = 32;

briar-api/src/org/briarproject/api/transport/TransportKeys.java

@@ -0,0 +1,44 @@
+package org.briarproject.api.transport;
+
+import org.briarproject.api.TransportId;
+
+/** Keys for communicating with a given contact over a given transport. */
+public class TransportKeys {
+
+	private final TransportId transportId;
+	private final IncomingKeys inPrev, inCurr, inNext;
+	private final OutgoingKeys outCurr;
+
+	public TransportKeys(TransportId transportId, IncomingKeys inPrev,
+			IncomingKeys inCurr, IncomingKeys inNext, OutgoingKeys outCurr) {
+		this.transportId = transportId;
+		this.inPrev = inPrev;
+		this.inCurr = inCurr;
+		this.inNext = inNext;
+		this.outCurr = outCurr;
+	}
+
+	public TransportId getTransportId() {
+		return transportId;
+	}
+
+	public IncomingKeys getPreviousIncomingKeys() {
+		return inPrev;
+	}
+
+	public IncomingKeys getCurrentIncomingKeys() {
+		return inCurr;
+	}
+
+	public IncomingKeys getNextIncomingKeys() {
+		return inNext;
+	}
+
+	public OutgoingKeys getCurrentOutgoingKeys() {
+		return outCurr;
+	}
+
+	public long getRotationPeriod() {
+		return outCurr.getRotationPeriod();
+	}
+}