Massive refactoring to use pseudonyms instead of nicknames for contacts.

The invitation and private messaging UIs are currently broken. Some key
rotation bugs were fixed; others may have been created (unit tests
needed). An encoding for private keys was added. Pseudonyms were moved
out of the messaging package and ratings were moved in.

briar-core/src/net/sf/briar/crypto/CryptoComponentImpl.java

@@ -11,10 +11,12 @@ import java.security.GeneralSecurityException;
 import java.security.KeyFactory;
 import java.security.KeyPair;
 import java.security.KeyPairGenerator;
+import java.security.PrivateKey;
 import java.security.PublicKey;
 import java.security.SecureRandom;
 import java.security.Security;
 import java.security.Signature;
+import java.security.interfaces.ECPrivateKey;
 import java.security.interfaces.ECPublicKey;
 import java.security.spec.ECField;
 import java.security.spec.ECFieldFp;
@@ -39,27 +41,33 @@ import org.spongycastle.crypto.modes.AEADBlockCipher;
 import org.spongycastle.crypto.modes.GCMBlockCipher;
 import org.spongycastle.jce.provider.BouncyCastleProvider;
 
-import com.google.inject.Inject;
-
 class CryptoComponentImpl implements CryptoComponent {
 
 	private static final String PROVIDER = "SC"; // Spongy Castle
-	private static final String AGREEMENT_KEY_PAIR_ALGO = "ECDH";
-	private static final int AGREEMENT_KEY_PAIR_BITS = 384;
-	private static final String AGREEMENT_ALGO = "ECDHC";
 	private static final String SECRET_KEY_ALGO = "AES";
 	private static final int SECRET_KEY_BYTES = 32; // 256 bits
-	private static final String KEY_DERIVATION_ALGO = "AES/CTR/NoPadding";
-	private static final int KEY_DERIVATION_IV_BYTES = 16; // 128 bits
 	private static final String DIGEST_ALGO = "SHA-384";
+	private static final String AGREEMENT_ALGO = "ECDHC";
+	private static final String AGREEMENT_KEY_PAIR_ALGO = "ECDH";
+	private static final int AGREEMENT_KEY_PAIR_BITS = 384;
+	private static final String SIGNATURE_ALGO = "ECDSA";
 	private static final String SIGNATURE_KEY_PAIR_ALGO = "ECDSA";
 	private static final int SIGNATURE_KEY_PAIR_BITS = 384;
-	private static final String SIGNATURE_ALGO = "ECDSA";
 	private static final String TAG_CIPHER_ALGO = "AES/ECB/NoPadding";
 	private static final int GCM_MAC_LENGTH = 16; // 128 bits
 	private static final String STORAGE_CIPHER_ALGO = "AES/GCM/NoPadding";
 	private static final int STORAGE_IV_LENGTH = 32; // 256 bits
+	private static final String KEY_DERIVATION_ALGO = "AES/CTR/NoPadding";
+	private static final int KEY_DERIVATION_IV_BYTES = 16; // 128 bits
 
+	// Labels for secret derivation
+	private static final byte[] MASTER = { 'M', 'A', 'S', 'T', 'E', 'R', '\0' };
+	private static final byte[] FIRST = { 'F', 'I', 'R', 'S', 'T', '\0' };
+	private static final byte[] ROTATE = { 'R', 'O', 'T', 'A', 'T', 'E', '\0' };
+	// Label for confirmation code derivation
+	private static final byte[] CODE = { 'C', 'O', 'D', 'E', '\0' };
+	// Label for invitation nonce derivation
+	private static final byte[] NONCE = { 'N', 'O', 'N', 'C', 'E', '\0' };
 	// Labels for key derivation
 	private static final byte[] A_TAG = { 'A', '_', 'T', 'A', 'G', '\0' };
 	private static final byte[] B_TAG = { 'B', '_', 'T', 'A', 'G', '\0' };
@@ -71,11 +79,6 @@ class CryptoComponentImpl implements CryptoComponent {
 		{ 'B', '_', 'F', 'R', 'A', 'M', 'E', '_', 'A', '\0' };
 	private static final byte[] B_FRAME_B =
 		{ 'B', '_', 'F', 'R', 'A', 'M', 'E', '_', 'B', '\0' };
-	// Labels for secret derivation
-	private static final byte[] FIRST = { 'F', 'I', 'R', 'S', 'T', '\0' };
-	private static final byte[] ROTATE = { 'R', 'O', 'T', 'A', 'T', 'E', '\0' };
-	// Label for confirmation code derivation
-	private static final byte[] CODE = { 'C', 'O', 'D', 'E', '\0' };
 	// Blank plaintext for key derivation
 	private static final byte[] KEY_DERIVATION_BLANK_PLAINTEXT =
 			new byte[SECRET_KEY_BYTES];
@@ -121,7 +124,6 @@ class CryptoComponentImpl implements CryptoComponent {
 	private final SecureRandom secureRandom;
 	private final ErasableKey temporaryStorageKey;
 
-	@Inject
 	CryptoComponentImpl() {
 		Security.addProvider(new BouncyCastleProvider());
 		try {
@@ -146,197 +148,6 @@ class CryptoComponentImpl implements CryptoComponent {
 		temporaryStorageKey = generateSecretKey();
 	}
 
-	public ErasableKey deriveTagKey(byte[] secret, boolean alice) {
-		if(alice) return deriveKey(secret, A_TAG, 0);
-		else return deriveKey(secret, B_TAG, 0);
-	}
-
-	public ErasableKey deriveFrameKey(byte[] secret, long connection,
-			boolean alice, boolean initiator) {
-		if(alice) {
-			if(initiator) return deriveKey(secret, A_FRAME_A, connection);
-			else return deriveKey(secret, A_FRAME_B, connection);
-		} else {
-			if(initiator) return deriveKey(secret, B_FRAME_A, connection);
-			else return deriveKey(secret, B_FRAME_B, connection);
-		}
-	}
-
-	private ErasableKey deriveKey(byte[] secret, byte[] label, long context) {
-		byte[] key = counterModeKdf(secret, label, context);
-		return new ErasableKeyImpl(key, SECRET_KEY_ALGO);
-	}
-
-	// Key derivation function based on a block cipher in CTR mode - see
-	// NIST SP 800-108, section 5.1
-	private byte[] counterModeKdf(byte[] secret, byte[] label, long context) {
-		// The secret must be usable as a key
-		if(secret.length != SECRET_KEY_BYTES)
-			throw new IllegalArgumentException();
-		// The label and context must leave a byte free for the counter
-		if(label.length + 4 >= KEY_DERIVATION_IV_BYTES)
-			throw new IllegalArgumentException();
-		byte[] ivBytes = new byte[KEY_DERIVATION_IV_BYTES];
-		System.arraycopy(label, 0, ivBytes, 0, label.length);
-		ByteUtils.writeUint32(context, ivBytes, label.length);
-		// Use the secret and the IV to encrypt a blank plaintext
-		IvParameterSpec iv = new IvParameterSpec(ivBytes);
-		ErasableKey key = new ErasableKeyImpl(secret, SECRET_KEY_ALGO);
-		try {
-			Cipher cipher = Cipher.getInstance(KEY_DERIVATION_ALGO, PROVIDER);
-			cipher.init(Cipher.ENCRYPT_MODE, key, iv);
-			byte[] output = cipher.doFinal(KEY_DERIVATION_BLANK_PLAINTEXT);
-			assert output.length == SECRET_KEY_BYTES;
-			return output;
-		} catch(GeneralSecurityException e) {
-			throw new RuntimeException(e);
-		}
-	}
-
-	public byte[] deriveInitialSecret(byte[] theirPublicKey,
-			KeyPair ourKeyPair, boolean alice) throws GeneralSecurityException {
-		PublicKey theirPublic = agreementKeyParser.parsePublicKey(
-				theirPublicKey);
-		MessageDigest messageDigest = getMessageDigest();
-		byte[] ourPublicKey = ourKeyPair.getPublic().getEncoded();
-		byte[] ourHash = messageDigest.digest(ourPublicKey);
-		byte[] theirHash = messageDigest.digest(theirPublicKey);
-		byte[] aliceInfo, bobInfo;
-		if(alice) {
-			aliceInfo = ourHash;
-			bobInfo = theirHash;
-		} else {
-			aliceInfo = theirHash;
-			bobInfo = ourHash;
-		}
-		// The raw secret comes from the key agreement algorithm
-		KeyAgreement keyAgreement = KeyAgreement.getInstance(AGREEMENT_ALGO,
-				PROVIDER);
-		keyAgreement.init(ourKeyPair.getPrivate());
-		keyAgreement.doPhase(theirPublic, true);
-		byte[] rawSecret = keyAgreement.generateSecret();
-		// Derive the cooked secret from the raw secret using the
-		// concatenation KDF
-		byte[] cookedSecret = concatenationKdf(rawSecret, FIRST, aliceInfo,
-				bobInfo);
-		ByteUtils.erase(rawSecret);
-		return cookedSecret;
-	}
-
-	// Key derivation function based on a hash function - see NIST SP 800-56A,
-	// section 5.8
-	private byte[] concatenationKdf(byte[] rawSecret, byte[] label,
-			byte[] initiatorInfo, byte[] responderInfo) {
-		// The output of the hash function must be long enough to use as a key
-		MessageDigest messageDigest = getMessageDigest();
-		if(messageDigest.getDigestLength() < SECRET_KEY_BYTES)
-			throw new RuntimeException();
-		// All fields are length-prefixed
-		byte[] length = new byte[1];
-		ByteUtils.writeUint8(rawSecret.length, length, 0);
-		messageDigest.update(length);
-		messageDigest.update(rawSecret);
-		ByteUtils.writeUint8(label.length, length, 0);
-		messageDigest.update(length);
-		messageDigest.update(label);
-		ByteUtils.writeUint8(initiatorInfo.length, length, 0);
-		messageDigest.update(length);
-		messageDigest.update(initiatorInfo);
-		ByteUtils.writeUint8(responderInfo.length, length, 0);
-		messageDigest.update(length);
-		messageDigest.update(responderInfo);
-		byte[] hash = messageDigest.digest();
-		// The secret is the first SECRET_KEY_BYTES bytes of the hash
-		byte[] output = new byte[SECRET_KEY_BYTES];
-		System.arraycopy(hash, 0, output, 0, SECRET_KEY_BYTES);
-		ByteUtils.erase(hash);
-		return output;
-	}
-
-	public byte[] deriveNextSecret(byte[] secret, long period) {
-		if(period < 0 || period > MAX_32_BIT_UNSIGNED)
-			throw new IllegalArgumentException();
-		return counterModeKdf(secret, ROTATE, period);
-	}
-
-	public void encodeTag(byte[] tag, Cipher tagCipher, ErasableKey tagKey,
-			long connection) {
-		if(tag.length < TAG_LENGTH) throw new IllegalArgumentException();
-		if(connection < 0 || connection > MAX_32_BIT_UNSIGNED)
-			throw new IllegalArgumentException();
-		for(int i = 0; i < TAG_LENGTH; i++) tag[i] = 0;
-		ByteUtils.writeUint32(connection, tag, 0);
-		try {
-			tagCipher.init(ENCRYPT_MODE, tagKey);
-			int encrypted = tagCipher.doFinal(tag, 0, TAG_LENGTH, tag);
-			if(encrypted != TAG_LENGTH) throw new IllegalArgumentException();
-		} catch(GeneralSecurityException e) {
-			// Unsuitable cipher or key
-			throw new IllegalArgumentException(e);
-		}
-	}
-
-	public int generateInvitationCode() {
-		int codeBytes = (int) Math.ceil(CODE_BITS / 8.0);
-		byte[] random = new byte[codeBytes];
-		secureRandom.nextBytes(random);
-		return ByteUtils.readUint(random, CODE_BITS);
-	}
-
-	public int[] deriveConfirmationCodes(byte[] secret) {
-		byte[] alice = counterModeKdf(secret, CODE, 0);
-		byte[] bob = counterModeKdf(secret, CODE, 1);
-		int[] codes = new int[2];
-		codes[0] = ByteUtils.readUint(alice, CODE_BITS);
-		codes[1] = ByteUtils.readUint(bob, CODE_BITS);
-		ByteUtils.erase(alice);
-		ByteUtils.erase(bob);
-		return codes;
-	}
-
-	public KeyPair generateAgreementKeyPair() {
-		KeyPair keyPair = agreementKeyPairGenerator.generateKeyPair();
-		// Check that the key pair uses NIST curve P-384
-		ECPublicKey ecPublicKey = checkP384Params(keyPair.getPublic());
-		// Return a public key that uses the SEC 1 encoding
-		ecPublicKey = new Sec1PublicKey(ecPublicKey, AGREEMENT_KEY_PAIR_BITS);
-		return new KeyPair(ecPublicKey, keyPair.getPrivate());
-	}
-
-	private ECPublicKey checkP384Params(PublicKey publicKey) {
-		if(!(publicKey instanceof ECPublicKey)) throw new RuntimeException();
-		ECPublicKey ecPublicKey = (ECPublicKey) publicKey;
-		ECParameterSpec params = ecPublicKey.getParams();
-		EllipticCurve curve = params.getCurve();
-		ECField field = curve.getField();
-		if(!(field instanceof ECFieldFp)) throw new RuntimeException();
-		BigInteger q = ((ECFieldFp) field).getP();
-		if(!q.equals(P_384_Q)) throw new RuntimeException();
-		if(!curve.getA().equals(P_384_A)) throw new RuntimeException();
-		if(!curve.getB().equals(P_384_B)) throw new RuntimeException();
-		if(!params.getGenerator().equals(P_384_G)) throw new RuntimeException();
-		if(!params.getOrder().equals(P_384_N)) throw new RuntimeException();
-		if(!(params.getCofactor() == P_384_H)) throw new RuntimeException();
-		return ecPublicKey;
-	}
-
-	public KeyParser getAgreementKeyParser() {
-		return agreementKeyParser;
-	}
-
-	public KeyPair generateSignatureKeyPair() {
-		KeyPair keyPair = signatureKeyPairGenerator.generateKeyPair();
-		// Check that the key pair uses NIST curve P-384
-		ECPublicKey ecPublicKey = checkP384Params(keyPair.getPublic());
-		// Return a public key that uses the SEC 1 encoding
-		ecPublicKey = new Sec1PublicKey(ecPublicKey, SIGNATURE_KEY_PAIR_BITS);
-		return new KeyPair(ecPublicKey, keyPair.getPrivate());
-	}
-
-	public KeyParser getSignatureKeyParser() {
-		return signatureKeyParser;
-	}
-
 	public ErasableKey generateSecretKey() {
 		byte[] b = new byte[SECRET_KEY_BYTES];
 		secureRandom.nextBytes(b);
@@ -368,6 +179,127 @@ class CryptoComponentImpl implements CryptoComponent {
 		}
 	}
 
+	public KeyPair generateAgreementKeyPair() {
+		KeyPair keyPair = agreementKeyPairGenerator.generateKeyPair();
+		// Check that the key pair uses NIST curve P-384
+		ECPublicKey publicKey = checkP384Params(keyPair.getPublic());
+		// Return a wrapper that uses the SEC 1 encoding
+		publicKey = new Sec1PublicKey(publicKey, AGREEMENT_KEY_PAIR_BITS);
+		ECPrivateKey privateKey = (ECPrivateKey) keyPair.getPrivate();
+		privateKey = new Sec1PrivateKey(privateKey, AGREEMENT_KEY_PAIR_BITS);
+		return new KeyPair(publicKey, privateKey);
+	}
+
+	public KeyParser getAgreementKeyParser() {
+		return agreementKeyParser;
+	}
+
+	public KeyPair generateSignatureKeyPair() {
+		KeyPair keyPair = signatureKeyPairGenerator.generateKeyPair();
+		// Check that the key pair uses NIST curve P-384
+		ECPublicKey publicKey = checkP384Params(keyPair.getPublic());
+		// Return a wrapper that uses the SEC 1 encoding
+		publicKey = new Sec1PublicKey(publicKey, SIGNATURE_KEY_PAIR_BITS);
+		ECPrivateKey privateKey = (ECPrivateKey) keyPair.getPrivate();
+		privateKey = new Sec1PrivateKey(privateKey, SIGNATURE_KEY_PAIR_BITS);
+		return new KeyPair(publicKey, privateKey);
+	}
+
+	public KeyParser getSignatureKeyParser() {
+		return signatureKeyParser;
+	}
+
+	public int generateInvitationCode() {
+		int codeBytes = (int) Math.ceil(CODE_BITS / 8.0);
+		byte[] random = new byte[codeBytes];
+		secureRandom.nextBytes(random);
+		return ByteUtils.readUint(random, CODE_BITS);
+	}
+
+	public int[] deriveConfirmationCodes(byte[] secret) {
+		byte[] alice = counterModeKdf(secret, CODE, 0);
+		byte[] bob = counterModeKdf(secret, CODE, 1);
+		int[] codes = new int[2];
+		codes[0] = ByteUtils.readUint(alice, CODE_BITS);
+		codes[1] = ByteUtils.readUint(bob, CODE_BITS);
+		ByteUtils.erase(alice);
+		ByteUtils.erase(bob);
+		return codes;
+	}
+
+	public byte[][] deriveInvitationNonces(byte[] secret) {
+		byte[] alice = counterModeKdf(secret, NONCE, 0);
+		byte[] bob = counterModeKdf(secret, NONCE, 1);
+		return new byte[][] { alice, bob };
+	}
+
+	public byte[] deriveMasterSecret(byte[] theirPublicKey,
+			KeyPair ourKeyPair, boolean alice) throws GeneralSecurityException {
+		PublicKey theirPub = agreementKeyParser.parsePublicKey(theirPublicKey);
+		MessageDigest messageDigest = getMessageDigest();
+		byte[] ourPublicKey = ourKeyPair.getPublic().getEncoded();
+		byte[] ourHash = messageDigest.digest(ourPublicKey);
+		byte[] theirHash = messageDigest.digest(theirPublicKey);
+		byte[] aliceInfo, bobInfo;
+		if(alice) {
+			aliceInfo = ourHash;
+			bobInfo = theirHash;
+		} else {
+			aliceInfo = theirHash;
+			bobInfo = ourHash;
+		}
+		PrivateKey ourPriv = ourKeyPair.getPrivate();
+		// The raw secret comes from the key agreement algorithm
+		byte[] raw = deriveSharedSecret(ourPriv, theirPub);
+		// Derive the cooked secret from the raw secret using the
+		// concatenation KDF
+		byte[] cooked = concatenationKdf(raw, MASTER, aliceInfo, bobInfo);
+		ByteUtils.erase(raw);
+		return cooked;
+	}
+
+	// Package access for testing
+	byte[] deriveSharedSecret(PrivateKey priv, PublicKey pub)
+			throws GeneralSecurityException {
+		KeyAgreement keyAgreement = KeyAgreement.getInstance(AGREEMENT_ALGO,
+				PROVIDER);
+		keyAgreement.init(priv);
+		keyAgreement.doPhase(pub, true);
+		return keyAgreement.generateSecret();
+	}
+
+	public byte[] deriveInitialSecret(byte[] secret, int transportIndex) {
+		if(transportIndex < 0) throw new IllegalArgumentException();
+		return counterModeKdf(secret, FIRST, transportIndex);
+	}
+
+	public byte[] deriveNextSecret(byte[] secret, long period) {
+		if(period < 0 || period > MAX_32_BIT_UNSIGNED)
+			throw new IllegalArgumentException();
+		return counterModeKdf(secret, ROTATE, period);
+	}
+
+	public ErasableKey deriveTagKey(byte[] secret, boolean alice) {
+		if(alice) return deriveKey(secret, A_TAG, 0);
+		else return deriveKey(secret, B_TAG, 0);
+	}
+
+	public ErasableKey deriveFrameKey(byte[] secret, long connection,
+			boolean alice, boolean initiator) {
+		if(alice) {
+			if(initiator) return deriveKey(secret, A_FRAME_A, connection);
+			else return deriveKey(secret, A_FRAME_B, connection);
+		} else {
+			if(initiator) return deriveKey(secret, B_FRAME_A, connection);
+			else return deriveKey(secret, B_FRAME_B, connection);
+		}
+	}
+
+	private ErasableKey deriveKey(byte[] secret, byte[] label, long context) {
+		byte[] key = counterModeKdf(secret, label, context);
+		return new ErasableKeyImpl(key, SECRET_KEY_ALGO);
+	}
+
 	public Cipher getTagCipher() {
 		try {
 			return Cipher.getInstance(TAG_CIPHER_ALGO, PROVIDER);
@@ -377,12 +309,28 @@ class CryptoComponentImpl implements CryptoComponent {
 	}
 
 	public AuthenticatedCipher getFrameCipher() {
-		// This code is specific to BouncyCastle because javax.crypto.Cipher
+		// This code is specific to Spongy Castle because javax.crypto.Cipher
 		// doesn't support additional authenticated data until Java 7
 		AEADBlockCipher cipher = new GCMBlockCipher(new AESEngine());
 		return new AuthenticatedCipherImpl(cipher, GCM_MAC_LENGTH);
 	}
 
+	public void encodeTag(byte[] tag, Cipher tagCipher, ErasableKey tagKey,
+			long connection) {
+		if(tag.length < TAG_LENGTH) throw new IllegalArgumentException();
+		if(connection < 0 || connection > MAX_32_BIT_UNSIGNED)
+			throw new IllegalArgumentException();
+		for(int i = 0; i < TAG_LENGTH; i++) tag[i] = 0;
+		ByteUtils.writeUint32(connection, tag, 0);
+		try {
+			tagCipher.init(ENCRYPT_MODE, tagKey);
+			int encrypted = tagCipher.doFinal(tag, 0, TAG_LENGTH, tag);
+			if(encrypted != TAG_LENGTH) throw new IllegalArgumentException();
+		} catch(GeneralSecurityException e) {
+			throw new IllegalArgumentException(e); // Unsuitable cipher or key
+		}
+	}
+
 	public byte[] encryptTemporaryStorage(byte[] input) {
 		// Generate a random IV
 		byte[] ivBytes = new byte[STORAGE_IV_LENGTH];
@@ -425,4 +373,77 @@ class CryptoComponentImpl implements CryptoComponent {
 			return null; // Invalid
 		}
 	}
+
+	private ECPublicKey checkP384Params(PublicKey publicKey) {
+		if(!(publicKey instanceof ECPublicKey)) throw new RuntimeException();
+		ECPublicKey ecPublicKey = (ECPublicKey) publicKey;
+		ECParameterSpec params = ecPublicKey.getParams();
+		EllipticCurve curve = params.getCurve();
+		ECField field = curve.getField();
+		if(!(field instanceof ECFieldFp)) throw new RuntimeException();
+		BigInteger q = ((ECFieldFp) field).getP();
+		if(!q.equals(P_384_Q)) throw new RuntimeException();
+		if(!curve.getA().equals(P_384_A)) throw new RuntimeException();
+		if(!curve.getB().equals(P_384_B)) throw new RuntimeException();
+		if(!params.getGenerator().equals(P_384_G)) throw new RuntimeException();
+		if(!params.getOrder().equals(P_384_N)) throw new RuntimeException();
+		if(!(params.getCofactor() == P_384_H)) throw new RuntimeException();
+		return ecPublicKey;
+	}
+
+	// Key derivation function based on a hash function - see NIST SP 800-56A,
+	// section 5.8
+	private byte[] concatenationKdf(byte[] rawSecret, byte[] label,
+			byte[] initiatorInfo, byte[] responderInfo) {
+		// The output of the hash function must be long enough to use as a key
+		MessageDigest messageDigest = getMessageDigest();
+		if(messageDigest.getDigestLength() < SECRET_KEY_BYTES)
+			throw new RuntimeException();
+		// All fields are length-prefixed
+		byte[] length = new byte[1];
+		ByteUtils.writeUint8(rawSecret.length, length, 0);
+		messageDigest.update(length);
+		messageDigest.update(rawSecret);
+		ByteUtils.writeUint8(label.length, length, 0);
+		messageDigest.update(length);
+		messageDigest.update(label);
+		ByteUtils.writeUint8(initiatorInfo.length, length, 0);
+		messageDigest.update(length);
+		messageDigest.update(initiatorInfo);
+		ByteUtils.writeUint8(responderInfo.length, length, 0);
+		messageDigest.update(length);
+		messageDigest.update(responderInfo);
+		byte[] hash = messageDigest.digest();
+		// The secret is the first SECRET_KEY_BYTES bytes of the hash
+		byte[] output = new byte[SECRET_KEY_BYTES];
+		System.arraycopy(hash, 0, output, 0, SECRET_KEY_BYTES);
+		ByteUtils.erase(hash);
+		return output;
+	}
+
+	// Key derivation function based on a block cipher in CTR mode - see
+	// NIST SP 800-108, section 5.1
+	private byte[] counterModeKdf(byte[] secret, byte[] label, long context) {
+		// The secret must be usable as a key
+		if(secret.length != SECRET_KEY_BYTES)
+			throw new IllegalArgumentException();
+		// The label and context must leave a byte free for the counter
+		if(label.length + 4 >= KEY_DERIVATION_IV_BYTES)
+			throw new IllegalArgumentException();
+		byte[] ivBytes = new byte[KEY_DERIVATION_IV_BYTES];
+		System.arraycopy(label, 0, ivBytes, 0, label.length);
+		ByteUtils.writeUint32(context, ivBytes, label.length);
+		// Use the secret and the IV to encrypt a blank plaintext
+		IvParameterSpec iv = new IvParameterSpec(ivBytes);
+		ErasableKey key = new ErasableKeyImpl(secret, SECRET_KEY_ALGO);
+		try {
+			Cipher cipher = Cipher.getInstance(KEY_DERIVATION_ALGO, PROVIDER);
+			cipher.init(Cipher.ENCRYPT_MODE, key, iv);
+			byte[] output = cipher.doFinal(KEY_DERIVATION_BLANK_PLAINTEXT);
+			assert output.length == SECRET_KEY_BYTES;
+			return output;
+		} catch(GeneralSecurityException e) {
+			throw new RuntimeException(e);
+		}
+	}
 }

briar-core/src/net/sf/briar/crypto/Sec1KeyParser.java

@@ -2,9 +2,13 @@ package net.sf.briar.crypto;
 
 import java.math.BigInteger;
 import java.security.KeyFactory;
+import java.security.PrivateKey;
 import java.security.PublicKey;
+import java.security.interfaces.ECPrivateKey;
+import java.security.interfaces.ECPublicKey;
 import java.security.spec.ECParameterSpec;
 import java.security.spec.ECPoint;
+import java.security.spec.ECPrivateKeySpec;
 import java.security.spec.ECPublicKeySpec;
 import java.security.spec.InvalidKeySpecException;
 
@@ -20,20 +24,22 @@ class Sec1KeyParser implements KeyParser {
 	private final KeyFactory keyFactory;
 	private final ECParameterSpec params;
 	private final BigInteger modulus;
-	private final int bytesPerInt, encodedKeyLength;
+	private final int keyBits, bytesPerInt, publicKeyBytes, privateKeyBytes;
 
 	Sec1KeyParser(KeyFactory keyFactory, ECParameterSpec params,
 			BigInteger modulus, int keyBits) {
 		this.keyFactory = keyFactory;
 		this.params = params;
 		this.modulus = modulus;
+		this.keyBits = keyBits;
 		bytesPerInt = (int) Math.ceil(keyBits / 8.0);
-		encodedKeyLength = 1 + 2 * bytesPerInt;
+		publicKeyBytes = 1 + 2 * bytesPerInt;
+		privateKeyBytes = bytesPerInt;
 	}
 
 	public PublicKey parsePublicKey(byte[] encodedKey)
 			throws InvalidKeySpecException {
-		if(encodedKey.length != encodedKeyLength)
+		if(encodedKey.length != publicKeyBytes)
 			throw new InvalidKeySpecException();
 		// The first byte must be 0x04
 		if(encodedKey[0] != 4) throw new InvalidKeySpecException();
@@ -52,9 +58,23 @@ class Sec1KeyParser implements KeyParser {
 		BigInteger lhs = y.multiply(y).mod(modulus);
 		BigInteger rhs = x.multiply(x).add(a).multiply(x).add(b).mod(modulus);
 		if(!lhs.equals(rhs)) throw new InvalidKeySpecException();
+		// FIXME: Verify that n times the point (x, y) = the point at infinity
 		// Construct a public key from the point (x, y) and the params
 		ECPoint pub = new ECPoint(x, y);
 		ECPublicKeySpec keySpec = new ECPublicKeySpec(pub, params);
-		return keyFactory.generatePublic(keySpec);
+		ECPublicKey k = (ECPublicKey) keyFactory.generatePublic(keySpec);
+		return new Sec1PublicKey(k, keyBits);
+	}
+
+	public PrivateKey parsePrivateKey(byte[] encodedKey)
+			throws InvalidKeySpecException {
+		if(encodedKey.length != privateKeyBytes)
+			throw new InvalidKeySpecException();
+		BigInteger s = new BigInteger(1, encodedKey); // Positive signum
+		if(s.compareTo(params.getOrder()) >= 0)
+			throw new InvalidKeySpecException();
+		ECPrivateKeySpec keySpec = new ECPrivateKeySpec(s, params);
+		ECPrivateKey k = (ECPrivateKey) keyFactory.generatePrivate(keySpec);
+		return new Sec1PrivateKey(k, keyBits);
 	}
 }

briar-core/src/net/sf/briar/crypto/Sec1PrivateKey.java

@@ -0,0 +1,57 @@
+package net.sf.briar.crypto;
+
+import java.math.BigInteger;
+import java.security.interfaces.ECPrivateKey;
+import java.security.spec.ECParameterSpec;
+
+class Sec1PrivateKey implements ECPrivateKey,
+org.spongycastle.jce.interfaces.ECPrivateKey {
+
+	private static final long serialVersionUID = -493100835871466670L;
+
+	private final ECPrivateKey key;
+	private final int privateKeyBytes;
+
+	Sec1PrivateKey(ECPrivateKey key, int keyBits) {
+		// Spongy Castle only accepts instances of its own interface, so we
+		// have to wrap an instance of that interface and delegate to it
+		if(!(key instanceof org.spongycastle.jce.interfaces.ECPrivateKey))
+			throw new IllegalArgumentException();
+		this.key = key;
+		privateKeyBytes = (int) Math.ceil(keyBits / 8.0);
+	}
+
+	public String getAlgorithm() {
+		return key.getAlgorithm();
+	}
+
+	public byte[] getEncoded() {
+		byte[] encodedKey = new byte[privateKeyBytes];
+		BigInteger s = key.getS();
+		// Copy up to privateKeyBytes bytes into exactly privateKeyBytes bytes
+		byte[] sBytes = s.toByteArray();
+		for(int i = 0; i < sBytes.length && i < privateKeyBytes; i++)
+			encodedKey[privateKeyBytes - 1 - i] = sBytes[sBytes.length - 1 - i];
+		return encodedKey;
+	}
+
+	public String getFormat() {
+		return "SEC1";
+	}
+
+	public ECParameterSpec getParams() {
+		return key.getParams();
+	}
+
+	public BigInteger getS() {
+		return key.getS();
+	}
+
+	public org.spongycastle.jce.spec.ECParameterSpec getParameters() {
+		return ((org.spongycastle.jce.interfaces.ECPrivateKey) key).getParameters();
+	}
+
+	public BigInteger getD() {
+		return ((org.spongycastle.jce.interfaces.ECPrivateKey) key).getD();
+	}
+}

briar-core/src/net/sf/briar/crypto/Sec1PublicKey.java

@@ -10,17 +10,22 @@ import java.security.spec.ECPoint;
  * Elliptic Curve Cryptography", section 2.3 (Certicom Corporation, May 2009).
  * Point compression is not used.
  */
-class Sec1PublicKey implements ECPublicKey {
+class Sec1PublicKey implements ECPublicKey,
+org.spongycastle.jce.interfaces.ECPublicKey {
 
 	private static final long serialVersionUID = -2722797033851423987L;
 
 	private final ECPublicKey key;
-	private final int bytesPerInt, encodedKeyLength;
+	private final int bytesPerInt, publicKeyBytes;
 
 	Sec1PublicKey(ECPublicKey key, int keyBits) {
+		// Spongy Castle only accepts instances of its own interface, so we
+		// have to wrap an instance of that interface and delegate to it
+		if(!(key instanceof org.spongycastle.jce.interfaces.ECPublicKey))
+			throw new IllegalArgumentException();
 		this.key = key;
 		bytesPerInt = (int) Math.ceil(keyBits / 8.0);
-		encodedKeyLength = 1 + 2 * bytesPerInt;
+		publicKeyBytes = 1 + 2 * bytesPerInt;
 	}
 
 	public String getAlgorithm() {
@@ -28,9 +33,10 @@ class Sec1PublicKey implements ECPublicKey {
 	}
 
 	public byte[] getEncoded() {
-		byte[] encodedKey = new byte[encodedKeyLength];
+		byte[] encodedKey = new byte[publicKeyBytes];
 		encodedKey[0] = 4;
-		BigInteger x = key.getW().getAffineX(), y = key.getW().getAffineY();
+		BigInteger x = key.getW().getAffineX();
+		BigInteger y = key.getW().getAffineY();
 		// Copy up to bytesPerInt bytes into exactly bytesPerInt bytes
 		byte[] xBytes = x.toByteArray();
 		for(int i = 0; i < xBytes.length && i < bytesPerInt; i++)
@@ -52,4 +58,12 @@ class Sec1PublicKey implements ECPublicKey {
 	public ECPoint getW() {
 		return key.getW();
 	}
+
+	public org.spongycastle.jce.spec.ECParameterSpec getParameters() {
+		return ((org.spongycastle.jce.interfaces.ECPublicKey) key).getParameters();
+	}
+
+	public org.spongycastle.math.ec.ECPoint getQ() {
+		return ((org.spongycastle.jce.interfaces.ECPublicKey) key).getQ();
+	}
 }

briar-core/src/net/sf/briar/db/Database.java

@@ -4,27 +4,28 @@ import java.io.IOException;
 import java.util.Collection;
 import java.util.Map;
 
+import net.sf.briar.api.Author;
+import net.sf.briar.api.AuthorId;
 import net.sf.briar.api.Contact;
 import net.sf.briar.api.ContactId;
-import net.sf.briar.api.Rating;
+import net.sf.briar.api.LocalAuthor;
 import net.sf.briar.api.TransportConfig;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.TransportProperties;
 import net.sf.briar.api.db.DbException;
 import net.sf.briar.api.db.GroupMessageHeader;
 import net.sf.briar.api.db.PrivateMessageHeader;
-import net.sf.briar.api.messaging.AuthorId;
 import net.sf.briar.api.messaging.Group;
 import net.sf.briar.api.messaging.GroupId;
-import net.sf.briar.api.messaging.LocalAuthor;
 import net.sf.briar.api.messaging.LocalGroup;
 import net.sf.briar.api.messaging.Message;
 import net.sf.briar.api.messaging.MessageId;
+import net.sf.briar.api.messaging.Rating;
 import net.sf.briar.api.messaging.RetentionAck;
 import net.sf.briar.api.messaging.RetentionUpdate;
 import net.sf.briar.api.messaging.SubscriptionAck;
 import net.sf.briar.api.messaging.SubscriptionUpdate;
 import net.sf.briar.api.messaging.TransportAck;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.messaging.TransportUpdate;
 import net.sf.briar.api.transport.Endpoint;
 import net.sf.briar.api.transport.TemporarySecret;
@@ -82,16 +83,17 @@ interface Database<T> {
 	void commitTransaction(T txn) throws DbException;
 
 	/**
-	 * Adds a contact with the given name to the database and returns an ID for
-	 * the contact.
+	 * Stores a contact with the given pseudonym, associated with the given
+	 * local pseudonym, and returns an ID for the contact.
 	 * <p>
 	 * Locking: contact write, retention write, subscription write, transport
 	 * write, window write.
 	 */
-	ContactId addContact(T txn, String name) throws DbException;
+	ContactId addContact(T txn, Author remote, AuthorId local)
+			throws DbException;
 
 	/**
-	 * Adds an endpoint to the database.
+	 * Stores an endpoint.
 	 * <p>
 	 * Locking: window write.
 	 */
@@ -108,7 +110,7 @@ interface Database<T> {
 	/**
 	 * Stores a pseudonym that the user can use to sign messages.
 	 * <p>
-	 * Locking: identity write.
+	 * Locking: contact write, identity write.
 	 */
 	void addLocalAuthor(T txn, LocalAuthor a) throws DbException;
 
@@ -162,12 +164,13 @@ interface Database<T> {
 	boolean addSubscription(T txn, Group g) throws DbException;
 
 	/**
-	 * Adds a new transport to the database and returns true if the transport
-	 * was not previously in the database.
+	 * Stores a transport and returns true if the transport was not previously
+	 * in the database.
 	 * <p>
 	 * Locking: transport write, window write.
 	 */
-	boolean addTransport(T txn, TransportId t) throws DbException;
+	boolean addTransport(T txn, TransportId t, long maxLatency)
+			throws DbException;
 
 	/**
 	 * Makes the given group visible to the given contact.
@@ -176,6 +179,13 @@ interface Database<T> {
 	 */
 	void addVisibility(T txn, ContactId c, GroupId g) throws DbException;
 
+	/**
+	 * Returns true if the database contains the given contact.
+	 * <p>
+	 * Locking: contact read.
+	 */
+	boolean containsContact(T txn, AuthorId a) throws DbException;
+
 	/**
 	 * Returns true if the database contains the given contact.
 	 * <p>
@@ -277,6 +287,13 @@ interface Database<T> {
 	 */
 	long getLastConnected(T txn, ContactId c) throws DbException;
 
+	/**
+	 * Returns the pseudonym with the given ID.
+	 * <p>
+	 * Locking: identitiy read.
+	 */
+	LocalAuthor getLocalAuthor(T txn, AuthorId a) throws DbException;
+
 	/**
 	 * Returns all pseudonyms that the user can use to sign messages.
 	 * <p>
@@ -291,6 +308,14 @@ interface Database<T> {
 	 */
 	Collection<LocalGroup> getLocalGroups(T txn) throws DbException;
 
+	/**
+	 * Returns the local transport properties for all transports.
+	 * <p>
+	 * Locking: transport read.
+	 */
+	Map<TransportId, TransportProperties> getLocalProperties(T txn)
+			throws DbException;
+
 	/**
 	 * Returns the local transport properties for the given transport.
 	 * <p>
@@ -509,6 +534,13 @@ interface Database<T> {
 	Collection<TransportAck> getTransportAcks(T txn, ContactId c)
 			throws DbException;
 
+	/**
+	 * Returns the maximum latencies of all local transports.
+	 * <p>
+	 * Locking: transport read.
+	 */
+	Map<TransportId, Long> getTransportLatencies(T txn) throws DbException;
+
 	/**
 	 * Returns a collection of transport updates for the given contact and
 	 * updates their expiry times using the given latency. Returns null if no
@@ -669,6 +701,15 @@ interface Database<T> {
 	 */
 	boolean setReadFlag(T txn, MessageId m, boolean read) throws DbException;
 
+	/**
+	 * Sets the remote transport properties for the given contact, replacing
+	 * any existing properties.
+	 * <p>
+	 * Locking: transport write.
+	 */
+	void setRemoteProperties(T txn, ContactId c,
+			Map<TransportId, TransportProperties> p) throws DbException;
+
 	/**
 	 * Updates the remote transport properties for the given contact and the
 	 * given transport, replacing any existing properties, unless an update

briar-core/src/net/sf/briar/db/DatabaseComponentImpl.java

@@ -2,7 +2,7 @@ package net.sf.briar.db;
 
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
-import static net.sf.briar.api.Rating.GOOD;
+import static net.sf.briar.api.messaging.Rating.GOOD;
 import static net.sf.briar.db.DatabaseConstants.BYTES_PER_SWEEP;
 import static net.sf.briar.db.DatabaseConstants.CRITICAL_FREE_SPACE;
 import static net.sf.briar.db.DatabaseConstants.MAX_BYTES_BETWEEN_SPACE_CHECKS;
@@ -23,12 +23,16 @@ import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 import java.util.logging.Logger;
 
+import net.sf.briar.api.Author;
+import net.sf.briar.api.AuthorId;
 import net.sf.briar.api.Contact;
 import net.sf.briar.api.ContactId;
-import net.sf.briar.api.Rating;
+import net.sf.briar.api.LocalAuthor;
 import net.sf.briar.api.TransportConfig;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.TransportProperties;
 import net.sf.briar.api.clock.Clock;
+import net.sf.briar.api.db.ContactExistsException;
 import net.sf.briar.api.db.DatabaseComponent;
 import net.sf.briar.api.db.DbException;
 import net.sf.briar.api.db.GroupMessageHeader;
@@ -57,22 +61,19 @@ import net.sf.briar.api.db.event.TransportAddedEvent;
 import net.sf.briar.api.db.event.TransportRemovedEvent;
 import net.sf.briar.api.lifecycle.ShutdownManager;
 import net.sf.briar.api.messaging.Ack;
-import net.sf.briar.api.messaging.Author;
-import net.sf.briar.api.messaging.AuthorId;
 import net.sf.briar.api.messaging.Group;
 import net.sf.briar.api.messaging.GroupId;
-import net.sf.briar.api.messaging.LocalAuthor;
 import net.sf.briar.api.messaging.LocalGroup;
 import net.sf.briar.api.messaging.Message;
 import net.sf.briar.api.messaging.MessageId;
 import net.sf.briar.api.messaging.Offer;
+import net.sf.briar.api.messaging.Rating;
 import net.sf.briar.api.messaging.Request;
 import net.sf.briar.api.messaging.RetentionAck;
 import net.sf.briar.api.messaging.RetentionUpdate;
 import net.sf.briar.api.messaging.SubscriptionAck;
 import net.sf.briar.api.messaging.SubscriptionUpdate;
 import net.sf.briar.api.messaging.TransportAck;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.messaging.TransportUpdate;
 import net.sf.briar.api.transport.Endpoint;
 import net.sf.briar.api.transport.TemporarySecret;
@@ -183,7 +184,8 @@ DatabaseCleaner.Callback {
 		listeners.remove(d);
 	}
 
-	public ContactId addContact(String name) throws DbException {
+	public ContactId addContact(Author remote, AuthorId local)
+			throws DbException {
 		ContactId c;
 		contactLock.writeLock().lock();
 		try {
@@ -197,7 +199,9 @@ DatabaseCleaner.Callback {
 						try {
 							T txn = db.startTransaction();
 							try {
-								c = db.addContact(txn, name);
+								if(db.containsContact(txn, remote.getId()))
+									throw new ContactExistsException();
+								c = db.addContact(txn, remote, local);
 								db.commitTransaction(txn);
 							} catch(DbException e) {
 								db.abortTransaction(txn);
@@ -257,6 +261,43 @@ DatabaseCleaner.Callback {
 		}
 	}
 
+	public void addLocalAuthor(LocalAuthor a) throws DbException {
+		contactLock.writeLock().lock();
+		try {
+			identityLock.writeLock().lock();
+			try {
+				T txn = db.startTransaction();
+				try {
+					db.addLocalAuthor(txn, a);
+					db.commitTransaction(txn);
+				} catch(DbException e) {
+					db.abortTransaction(txn);
+					throw e;
+				}
+			} finally {
+				identityLock.writeLock().unlock();
+			}
+		} finally {
+			contactLock.writeLock().unlock();
+		}
+	}
+
+	public void addLocalGroup(LocalGroup g) throws DbException {
+		identityLock.writeLock().lock();
+		try {
+			T txn = db.startTransaction();
+			try {
+				db.addLocalGroup(txn, g);
+				db.commitTransaction(txn);
+			} catch(DbException e) {
+				db.abortTransaction(txn);
+				throw e;
+			}
+		} finally {
+			identityLock.writeLock().unlock();
+		}
+	}
+
 	public void addLocalGroupMessage(Message m) throws DbException {
 		boolean added = false;
 		contactLock.readLock().lock();
@@ -430,38 +471,6 @@ DatabaseCleaner.Callback {
 		return true;
 	}
 
-	public void addLocalAuthor(LocalAuthor a) throws DbException {
-		identityLock.writeLock().lock();
-		try {
-			T txn = db.startTransaction();
-			try {
-				db.addLocalAuthor(txn, a);
-				db.commitTransaction(txn);
-			} catch(DbException e) {
-				db.abortTransaction(txn);
-				throw e;
-			}
-		} finally {
-			identityLock.writeLock().unlock();
-		}
-	}
-
-	public void addLocalGroup(LocalGroup g) throws DbException {
-		identityLock.writeLock().lock();
-		try {
-			T txn = db.startTransaction();
-			try {
-				db.addLocalGroup(txn, g);
-				db.commitTransaction(txn);
-			} catch(DbException e) {
-				db.abortTransaction(txn);
-				throw e;
-			}
-		} finally {
-			identityLock.writeLock().unlock();
-		}
-	}
-
 	public void addSecrets(Collection<TemporarySecret> secrets)
 			throws DbException {
 		contactLock.readLock().lock();
@@ -498,7 +507,8 @@ DatabaseCleaner.Callback {
 		}
 	}
 
-	public boolean addTransport(TransportId t) throws DbException {
+	public boolean addTransport(TransportId t, long maxLatency)
+			throws DbException {
 		boolean added;
 		transportLock.writeLock().lock();
 		try {
@@ -506,7 +516,7 @@ DatabaseCleaner.Callback {
 			try {
 				T txn = db.startTransaction();
 				try {
-					added = db.addTransport(txn, t);
+					added = db.addTransport(txn, t, maxLatency);
 					db.commitTransaction(txn);
 				} catch(DbException e) {
 					db.abortTransaction(txn);
@@ -518,7 +528,7 @@ DatabaseCleaner.Callback {
 		} finally {
 			transportLock.writeLock().unlock();
 		}
-		if(added) callListeners(new TransportAddedEvent(t));
+		if(added) callListeners(new TransportAddedEvent(t, maxLatency));
 		return added;
 	}
 
@@ -947,6 +957,23 @@ DatabaseCleaner.Callback {
 		}
 	}
 
+	public LocalAuthor getLocalAuthor(AuthorId a) throws DbException {
+		identityLock.readLock().lock();
+		try {
+			T txn = db.startTransaction();
+			try {
+				LocalAuthor localAuthor = db.getLocalAuthor(txn, a);
+				db.commitTransaction(txn);
+				return localAuthor;
+			} catch(DbException e) {
+				db.abortTransaction(txn);
+				throw e;
+			}
+		} finally {
+			identityLock.readLock().unlock();
+		}
+	}
+
 	public Collection<LocalAuthor> getLocalAuthors() throws DbException {
 		identityLock.readLock().lock();
 		try {
@@ -981,6 +1008,25 @@ DatabaseCleaner.Callback {
 		}
 	}
 
+	public Map<TransportId, TransportProperties> getLocalProperties()
+			throws DbException {
+		transportLock.readLock().lock();
+		try {
+			T txn = db.startTransaction();
+			try {
+				Map<TransportId, TransportProperties> properties =
+						db.getLocalProperties(txn);
+				db.commitTransaction(txn);
+				return properties;
+			} catch(DbException e) {
+				db.abortTransaction(txn);
+				throw e;
+			}
+		} finally {
+			transportLock.readLock().unlock();
+		}
+	}
+
 	public TransportProperties getLocalProperties(TransportId t)
 			throws DbException {
 		transportLock.readLock().lock();
@@ -1197,6 +1243,24 @@ DatabaseCleaner.Callback {
 		}
 	}
 
+	public Map<TransportId, Long> getTransportLatencies() throws DbException {
+		transportLock.readLock().lock();
+		try {
+			T txn = db.startTransaction();
+			try {
+				Map<TransportId, Long> latencies =
+						db.getTransportLatencies(txn);
+				db.commitTransaction(txn);
+				return latencies;
+			} catch(DbException e) {
+				db.abortTransaction(txn);
+				throw e;
+			}
+		} finally {
+			transportLock.readLock().unlock();
+		}
+	}
+
 	public Map<GroupId, Integer> getUnreadMessageCounts() throws DbException {
 		messageLock.readLock().lock();
 		try {
@@ -1785,6 +1849,30 @@ DatabaseCleaner.Callback {
 		}
 	}
 
+	public void setRemoteProperties(ContactId c,
+			Map<TransportId, TransportProperties> p) throws DbException {
+		contactLock.readLock().lock();
+		try {
+			transportLock.writeLock().lock();
+			try {
+				T txn = db.startTransaction();
+				try {
+					if(!db.containsContact(txn, c))
+						throw new NoSuchContactException();
+					db.setRemoteProperties(txn, c, p);
+					db.commitTransaction(txn);
+				} catch(DbException e) {
+					db.abortTransaction(txn);
+					throw e;
+				}
+			} finally {
+				transportLock.writeLock().unlock();
+			}
+		} finally {
+			contactLock.readLock().unlock();
+		}
+	}
+
 	public void setSeen(ContactId c, Collection<MessageId> seen)
 			throws DbException {
 		contactLock.readLock().lock();

briar-core/src/net/sf/briar/db/H2Database.java

@@ -9,7 +9,6 @@ import java.util.Arrays;
 import java.util.Properties;
 
 import net.sf.briar.api.clock.Clock;
-import net.sf.briar.api.crypto.Password;
 import net.sf.briar.api.db.DatabaseConfig;
 import net.sf.briar.api.db.DbException;
 import net.sf.briar.util.FileUtils;
@@ -26,7 +25,7 @@ class H2Database extends JdbcDatabase {
 
 	private final File home;
 	private final String url;
-	private final Password password;
+	private final char[] password;
 	private final long maxSize;
 
 	@Inject
@@ -76,13 +75,12 @@ class H2Database extends JdbcDatabase {
 	@Override
 	protected Connection createConnection() throws SQLException {
 		Properties props = new Properties();
-		props.setProperty("user", "b");
-		char[] passwordArray = password.getPassword();
-		props.put("password", passwordArray);
+		props.setProperty("user", "user");
+		props.put("password", password);
 		try {
 			return DriverManager.getConnection(url, props);
 		} finally {
-			Arrays.fill(passwordArray, (char) 0);
+			Arrays.fill(password, (char) 0);
 		}
 	}
 }

briar-core/src/net/sf/briar/db/JdbcDatabase.java

@@ -4,9 +4,9 @@ import static java.sql.Types.BINARY;
 import static java.sql.Types.VARCHAR;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
-import static net.sf.briar.api.Rating.UNRATED;
 import static net.sf.briar.api.messaging.MessagingConstants.MAX_SUBSCRIPTIONS;
 import static net.sf.briar.api.messaging.MessagingConstants.RETENTION_MODULUS;
+import static net.sf.briar.api.messaging.Rating.UNRATED;
 import static net.sf.briar.db.ExponentialBackoff.calculateExpiry;
 
 import java.io.File;
@@ -27,30 +27,30 @@ import java.util.Map;
 import java.util.Map.Entry;
 import java.util.logging.Logger;
 
+import net.sf.briar.api.Author;
+import net.sf.briar.api.AuthorId;
 import net.sf.briar.api.Contact;
 import net.sf.briar.api.ContactId;
-import net.sf.briar.api.Rating;
+import net.sf.briar.api.LocalAuthor;
 import net.sf.briar.api.TransportConfig;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.TransportProperties;
 import net.sf.briar.api.clock.Clock;
 import net.sf.briar.api.db.DbClosedException;
 import net.sf.briar.api.db.DbException;
 import net.sf.briar.api.db.GroupMessageHeader;
 import net.sf.briar.api.db.PrivateMessageHeader;
-import net.sf.briar.api.messaging.Author;
-import net.sf.briar.api.messaging.AuthorId;
 import net.sf.briar.api.messaging.Group;
 import net.sf.briar.api.messaging.GroupId;
-import net.sf.briar.api.messaging.LocalAuthor;
 import net.sf.briar.api.messaging.LocalGroup;
 import net.sf.briar.api.messaging.Message;
 import net.sf.briar.api.messaging.MessageId;
+import net.sf.briar.api.messaging.Rating;
 import net.sf.briar.api.messaging.RetentionAck;
 import net.sf.briar.api.messaging.RetentionUpdate;
 import net.sf.briar.api.messaging.SubscriptionAck;
 import net.sf.briar.api.messaging.SubscriptionUpdate;
 import net.sf.briar.api.messaging.TransportAck;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.messaging.TransportUpdate;
 import net.sf.briar.api.transport.Endpoint;
 import net.sf.briar.api.transport.TemporarySecret;
@@ -85,8 +85,18 @@ abstract class JdbcDatabase implements Database<Connection> {
 	private static final String CREATE_CONTACTS =
 			"CREATE TABLE contacts"
 					+ " (contactId COUNTER,"
+					+ " authorId HASH NOT NULL,"
 					+ " name VARCHAR NOT NULL,"
-					+ " PRIMARY KEY (contactId))";
+					+ " publicKey BINARY NOT NULL,"
+					+ " localAuthorId HASH NOT NULL,"
+					+ " PRIMARY KEY (contactId),"
+					+ " UNIQUE (authorId),"
+					+ " FOREIGN KEY (localAuthorId)"
+					+ " REFERENCES localAuthors (authorId)"
+					+ " ON DELETE RESTRICT)"; // Deletion not allowed
+
+	private static final String INDEX_CONTACTS_BY_AUTHOR =
+			"CREATE INDEX contactsByAuthor ON contacts (authorId)";
 
 	// Locking: subscription
 	// Dependents: message
@@ -234,7 +244,10 @@ abstract class JdbcDatabase implements Database<Connection> {
 	// Locking: transport
 	// Dependents: window
 	private static final String CREATE_TRANSPORTS =
-			"CREATE TABLE transports (transportId HASH NOT NULL)";
+			"CREATE TABLE transports"
+					+ " (transportId HASH NOT NULL,"
+					+ " maxLatency BIGINT NOT NULL,"
+					+ " PRIMARY KEY (transportId))";
 
 	// Locking: transport
 	private static final String CREATE_TRANSPORT_CONFIGS =
@@ -305,8 +318,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " (contactId INT NOT NULL,"
 					+ " transportId HASH NOT NULL,"
 					+ " epoch BIGINT NOT NULL,"
-					+ " clockDiff BIGINT NOT NULL,"
-					+ " latency BIGINT NOT NULL,"
 					+ " alice BOOLEAN NOT NULL,"
 					+ " PRIMARY KEY (contactId, transportId),"
 					+ " FOREIGN KEY (contactId)"
@@ -401,6 +412,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			s.executeUpdate(insertTypeNames(CREATE_LOCAL_AUTHORS));
 			s.executeUpdate(insertTypeNames(CREATE_LOCAL_GROUPS));
 			s.executeUpdate(insertTypeNames(CREATE_CONTACTS));
+			s.executeUpdate(INDEX_CONTACTS_BY_AUTHOR);
 			s.executeUpdate(insertTypeNames(CREATE_GROUPS));
 			s.executeUpdate(insertTypeNames(CREATE_GROUP_VISIBILITIES));
 			s.executeUpdate(insertTypeNames(CREATE_CONTACT_GROUPS));
@@ -538,15 +550,20 @@ abstract class JdbcDatabase implements Database<Connection> {
 		if(interrupted) Thread.currentThread().interrupt();
 	}
 
-	public ContactId addContact(Connection txn, String name)
+	public ContactId addContact(Connection txn, Author remote, AuthorId local)
 			throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
 			// Create a contact row
-			String sql = "INSERT INTO contacts (name) VALUES (?)";
+			String sql = "INSERT INTO contacts"
+					+ " (authorId, name, publicKey, localAuthorId)"
+					+ " VALUES (?, ?, ?, ?)";
 			ps = txn.prepareStatement(sql);
-			ps.setString(1, name);
+			ps.setBytes(1, remote.getId().getBytes());
+			ps.setString(2, remote.getName());
+			ps.setBytes(3, remote.getPublicKey());
+			ps.setBytes(4, local.getBytes());
 			int affected = ps.executeUpdate();
 			if(affected != 1) throw new DbStateException();
 			ps.close();
@@ -612,11 +629,11 @@ abstract class JdbcDatabase implements Database<Connection> {
 				ps.setBytes(2, t);
 				ps.addBatch();
 			}
-			int[] affectedBatch = ps.executeBatch();
-			if(affectedBatch.length != transports.size())
+			int[] batchAffected = ps.executeBatch();
+			if(batchAffected.length != transports.size())
 				throw new DbStateException();
-			for(int i = 0; i < affectedBatch.length; i++) {
-				if(affectedBatch[i] != 1) throw new DbStateException();
+			for(int i = 0; i < batchAffected.length; i++) {
+				if(batchAffected[i] != 1) throw new DbStateException();
 			}
 			ps.close();
 			return c;
@@ -630,16 +647,14 @@ abstract class JdbcDatabase implements Database<Connection> {
 	public void addEndpoint(Connection txn, Endpoint ep) throws DbException {
 		PreparedStatement ps = null;
 		try {
-			String sql = "INSERT INTO endpoints (contactId, transportId,"
-					+ " epoch, clockDiff, latency, alice)"
-					+ " VALUES (?, ?, ?, ?, ?, ?)";
+			String sql = "INSERT INTO endpoints"
+					+ " (contactId, transportId, epoch, alice)"
+					+ " VALUES (?, ?, ?, ?)";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, ep.getContactId().getInt());
 			ps.setBytes(2, ep.getTransportId().getBytes());
 			ps.setLong(3, ep.getEpoch());
-			ps.setLong(4, ep.getClockDifference());
-			ps.setLong(5, ep.getLatency());
-			ps.setBoolean(6, ep.getAlice());
+			ps.setBoolean(4, ep.getAlice());
 			int affected = ps.executeUpdate();
 			if(affected != 1) throw new DbStateException();
 			ps.close();
@@ -900,7 +915,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
-	public boolean addTransport(Connection txn, TransportId t)
+	public boolean addTransport(Connection txn, TransportId t, long maxLatency)
 			throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
@@ -916,9 +931,11 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.close();
 			if(found) return false;
 			// Create a transport row
-			sql = "INSERT INTO transports (transportId) VALUES (?)";
+			sql = "INSERT INTO transports (transportId, maxLatency)"
+					+ " VALUES (?, ?)";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, t.getBytes());
+			ps.setLong(2, maxLatency);
 			int affected = ps.executeUpdate();
 			if(affected != 1) throw new DbStateException();
 			ps.close();
@@ -984,6 +1001,27 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	public boolean containsContact(Connection txn, AuthorId a)
+			throws DbException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT NULL FROM contacts WHERE authorId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, a.getBytes());
+			rs = ps.executeQuery();
+			boolean found = rs.next();
+			if(rs.next()) throw new DbStateException();
+			rs.close();
+			ps.close();
+			return found;
+		} catch(SQLException e) {
+			tryToClose(rs);
+			tryToClose(ps);
+			throw new DbException(e);
+		}
+	}
+
 	public boolean containsContact(Connection txn, ContactId c)
 			throws DbException {
 		PreparedStatement ps = null;
@@ -1117,7 +1155,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT name, lastConnected"
+			String sql = "SELECT authorId, name, publicKey, lastConnected"
 					+ " FROM contacts AS c"
 					+ " JOIN connectionTimes AS ct"
 					+ " ON c.contactId = ct.contactId"
@@ -1126,11 +1164,14 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(1, c.getInt());
 			rs = ps.executeQuery();
 			if(!rs.next()) throw new DbStateException();
-			String name = rs.getString(1);
-			long lastConnected = rs.getLong(2);
+			AuthorId authorId = new AuthorId(rs.getBytes(1));
+			String name = rs.getString(2);
+			byte[] publicKey = rs.getBytes(3);
+			long lastConnected = rs.getLong(4);
 			rs.close();
 			ps.close();
-			return new Contact(c, name, lastConnected);
+			Author author = new Author(authorId, name, publicKey);
+			return new Contact(c, author, lastConnected);
 		} catch(SQLException e) {
 			tryToClose(rs);
 			tryToClose(ps);
@@ -1163,7 +1204,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT c.contactId, name, lastConnected"
+			String sql = "SELECT c.contactId, authorId, name, publicKey,"
+					+ " lastConnected"
 					+ " FROM contacts AS c"
 					+ " JOIN connectionTimes AS ct"
 					+ " ON c.contactId = ct.contactId";
@@ -1171,10 +1213,13 @@ abstract class JdbcDatabase implements Database<Connection> {
 			rs = ps.executeQuery();
 			List<Contact> contacts = new ArrayList<Contact>();
 			while(rs.next()) {
-				ContactId id = new ContactId(rs.getInt(1));
-				String name = rs.getString(2);
-				long lastConnected = rs.getLong(3);
-				contacts.add(new Contact(id, name, lastConnected));
+				ContactId contactId = new ContactId(rs.getInt(1));
+				AuthorId authorId = new AuthorId(rs.getBytes(2));
+				String name = rs.getString(3);
+				byte[] publicKey = rs.getBytes(4);
+				long lastConnected = rs.getLong(5);
+				Author author = new Author(authorId, name, publicKey);
+				contacts.add(new Contact(contactId, author, lastConnected));
 			}
 			rs.close();
 			ps.close();
@@ -1191,8 +1236,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT contactId, transportId, epoch, clockDiff,"
-					+ " latency, alice"
+			String sql = "SELECT contactId, transportId, epoch, alice"
 					+ " FROM endpoints";
 			ps = txn.prepareStatement(sql);
 			rs = ps.executeQuery();
@@ -1201,11 +1245,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 				ContactId c = new ContactId(rs.getInt(1));
 				TransportId t = new TransportId(rs.getBytes(2));
 				long epoch = rs.getLong(3);
-				long clockDiff = rs.getLong(4);
-				long latency = rs.getLong(5);
-				boolean alice = rs.getBoolean(6);
-				endpoints.add(new Endpoint(c, t, epoch, clockDiff, latency,
-						alice));
+				boolean alice = rs.getBoolean(4);
+				endpoints.add(new Endpoint(c, t, epoch, alice));
 			}
 			return Collections.unmodifiableList(endpoints);
 		} catch(SQLException e) {
@@ -1287,6 +1328,30 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	public LocalAuthor getLocalAuthor(Connection txn, AuthorId a)
+			throws DbException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT name, publicKey, privateKey FROM localAuthors"
+					+ " WHERE authorId = ?";
+			ps = txn.prepareStatement(sql);
+			rs = ps.executeQuery();
+			if(!rs.next()) throw new DbStateException();
+			AuthorId id = new AuthorId(rs.getBytes(1));
+			LocalAuthor localAuthor = new LocalAuthor(id, rs.getString(2),
+					rs.getBytes(3), rs.getBytes(4));
+			if(rs.next()) throw new DbStateException();
+			rs.close();
+			ps.close();
+			return localAuthor;
+		} catch(SQLException e) {
+			tryToClose(rs);
+			tryToClose(ps);
+			throw new DbException(e);
+		}
+	}
+
 	public Collection<LocalAuthor> getLocalAuthors(Connection txn)
 			throws DbException {
 		PreparedStatement ps = null;
@@ -1337,6 +1402,40 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	public Map<TransportId, TransportProperties> getLocalProperties(
+			Connection txn) throws DbException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT transportId, key, value"
+					+ " FROM transportProperties"
+					+ " ORDER BY transportId";
+			ps = txn.prepareStatement(sql);
+			rs = ps.executeQuery();
+			Map<TransportId, TransportProperties> properties =
+					new HashMap<TransportId, TransportProperties>();
+			TransportId lastId = null;
+			TransportProperties p = null;
+			while(rs.next()) {
+				TransportId id = new TransportId(rs.getBytes(1));
+				String key = rs.getString(2), value = rs.getString(3);
+				if(!id.equals(lastId)) {
+					p = new TransportProperties();
+					properties.put(id, p);
+					lastId = id;
+				}
+				p.put(key, value);
+			}
+			rs.close();
+			ps.close();
+			return Collections.unmodifiableMap(properties);
+		} catch(SQLException e) {
+			tryToClose(rs);
+			tryToClose(ps);
+			throw new DbException(e);
+		}
+	}
+
 	public TransportProperties getLocalProperties(Connection txn, TransportId t)
 			throws DbException {
 		PreparedStatement ps = null;
@@ -1437,86 +1536,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
-	public Collection<PrivateMessageHeader> getPrivateMessageHeaders(
-			Connection txn) throws DbException {
-		PreparedStatement ps = null;
-		ResultSet rs = null;
-		try {
-			String sql = "SELECT m.messageId, parentId, contentType, subject,"
-					+ " timestamp, m.contactId, read, starred, seen"
-					+ " FROM messages AS m"
-					+ " JOIN statuses AS s"
-					+ " ON m.messageId = s.messageId"
-					+ " AND m.contactId = s.contactId"
-					+ " WHERE groupId IS NULL";
-			ps = txn.prepareStatement(sql);
-			rs = ps.executeQuery();
-			List<PrivateMessageHeader> headers =
-					new ArrayList<PrivateMessageHeader>();
-			while(rs.next()) {
-				MessageId id = new MessageId(rs.getBytes(1));
-				byte[] b = rs.getBytes(2);
-				MessageId parent = b == null ? null : new MessageId(b);
-				String contentType = rs.getString(3);
-				String subject = rs.getString(4);
-				long timestamp = rs.getLong(5);
-				ContactId contactId = new ContactId(rs.getInt(6));
-				boolean read = rs.getBoolean(7);
-				boolean starred = rs.getBoolean(8);
-				boolean seen = rs.getBoolean(9);
-				headers.add(new PrivateMessageHeader(id, parent, contentType,
-						subject, timestamp, read, starred, contactId, seen));
-			}
-			rs.close();
-			ps.close();
-			return Collections.unmodifiableList(headers);
-		} catch(SQLException e) {
-			tryToClose(rs);
-			tryToClose(ps);
-			throw new DbException(e);
-		}
-	}
-
-	public Collection<PrivateMessageHeader> getPrivateMessageHeaders(
-			Connection txn, ContactId c) throws DbException {
-		PreparedStatement ps = null;
-		ResultSet rs = null;
-		try {
-			String sql = "SELECT m.messageId, parentId, contentType, subject,"
-					+ " timestamp, read, starred, seen"
-					+ " FROM messages AS m"
-					+ " JOIN statuses AS s"
-					+ " ON m.messageId = s.messageId"
-					+ " AND m.contactId = s.contactId"
-					+ " WHERE m.contactId = ? AND groupId IS NULL";
-			ps = txn.prepareStatement(sql);
-			ps.setInt(1, c.getInt());
-			rs = ps.executeQuery();
-			List<PrivateMessageHeader> headers =
-					new ArrayList<PrivateMessageHeader>();
-			while(rs.next()) {
-				MessageId id = new MessageId(rs.getBytes(1));
-				byte[] b = rs.getBytes(2);
-				MessageId parent = b == null ? null : new MessageId(b);
-				String contentType = rs.getString(3);
-				String subject = rs.getString(4);
-				long timestamp = rs.getLong(5);
-				boolean read = rs.getBoolean(6);
-				boolean starred = rs.getBoolean(7);
-				boolean seen = rs.getBoolean(8);
-				headers.add(new PrivateMessageHeader(id, parent, contentType,
-						subject, timestamp, read, starred, c, seen));
-			}
-			rs.close();
-			ps.close();
-			return Collections.unmodifiableList(headers);
-		} catch(SQLException e) {
-			tryToClose(rs);
-			tryToClose(ps);
-			throw new DbException(e);
-		}
-	}
-
 	public Collection<MessageId> getMessagesByAuthor(Connection txn, AuthorId a)
 			throws DbException {
 		PreparedStatement ps = null;
@@ -1680,6 +1699,86 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	public Collection<PrivateMessageHeader> getPrivateMessageHeaders(
+			Connection txn) throws DbException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT m.messageId, parentId, contentType, subject,"
+					+ " timestamp, m.contactId, read, starred, seen"
+					+ " FROM messages AS m"
+					+ " JOIN statuses AS s"
+					+ " ON m.messageId = s.messageId"
+					+ " AND m.contactId = s.contactId"
+					+ " WHERE groupId IS NULL";
+			ps = txn.prepareStatement(sql);
+			rs = ps.executeQuery();
+			List<PrivateMessageHeader> headers =
+					new ArrayList<PrivateMessageHeader>();
+			while(rs.next()) {
+				MessageId id = new MessageId(rs.getBytes(1));
+				byte[] b = rs.getBytes(2);
+				MessageId parent = b == null ? null : new MessageId(b);
+				String contentType = rs.getString(3);
+				String subject = rs.getString(4);
+				long timestamp = rs.getLong(5);
+				ContactId contactId = new ContactId(rs.getInt(6));
+				boolean read = rs.getBoolean(7);
+				boolean starred = rs.getBoolean(8);
+				boolean seen = rs.getBoolean(9);
+				headers.add(new PrivateMessageHeader(id, parent, contentType,
+						subject, timestamp, read, starred, contactId, seen));
+			}
+			rs.close();
+			ps.close();
+			return Collections.unmodifiableList(headers);
+		} catch(SQLException e) {
+			tryToClose(rs);
+			tryToClose(ps);
+			throw new DbException(e);
+		}
+	}
+
+	public Collection<PrivateMessageHeader> getPrivateMessageHeaders(
+			Connection txn, ContactId c) throws DbException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT m.messageId, parentId, contentType, subject,"
+					+ " timestamp, read, starred, seen"
+					+ " FROM messages AS m"
+					+ " JOIN statuses AS s"
+					+ " ON m.messageId = s.messageId"
+					+ " AND m.contactId = s.contactId"
+					+ " WHERE m.contactId = ? AND groupId IS NULL";
+			ps = txn.prepareStatement(sql);
+			ps.setInt(1, c.getInt());
+			rs = ps.executeQuery();
+			List<PrivateMessageHeader> headers =
+					new ArrayList<PrivateMessageHeader>();
+			while(rs.next()) {
+				MessageId id = new MessageId(rs.getBytes(1));
+				byte[] b = rs.getBytes(2);
+				MessageId parent = b == null ? null : new MessageId(b);
+				String contentType = rs.getString(3);
+				String subject = rs.getString(4);
+				long timestamp = rs.getLong(5);
+				boolean read = rs.getBoolean(6);
+				boolean starred = rs.getBoolean(7);
+				boolean seen = rs.getBoolean(8);
+				headers.add(new PrivateMessageHeader(id, parent, contentType,
+						subject, timestamp, read, starred, c, seen));
+			}
+			rs.close();
+			ps.close();
+			return Collections.unmodifiableList(headers);
+		} catch(SQLException e) {
+			tryToClose(rs);
+			tryToClose(ps);
+			throw new DbException(e);
+		}
+	}
+
 	public Rating getRating(Connection txn, AuthorId a) throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
@@ -1834,6 +1933,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 				if(!id.equals(lastId)) {
 					p = new TransportProperties();
 					properties.put(id, p);
+					lastId = id;
 				}
 				p.put(key, value);
 			}
@@ -1934,9 +2034,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT e.contactId, e.transportId, epoch,"
-					+ " clockDiff, latency, alice, period, secret, outgoing,"
-					+ " centre, bitmap"
+			String sql = "SELECT e.contactId, e.transportId, epoch, alice,"
+					+ " period, secret, outgoing, centre, bitmap"
 					+ " FROM endpoints AS e"
 					+ " JOIN secrets AS s"
 					+ " ON e.contactId = s.contactId"
@@ -1948,16 +2047,14 @@ abstract class JdbcDatabase implements Database<Connection> {
 				ContactId c = new ContactId(rs.getInt(1));
 				TransportId t = new TransportId(rs.getBytes(2));
 				long epoch = rs.getLong(3);
-				long clockDiff = rs.getLong(4);
-				long latency = rs.getLong(5);
-				boolean alice = rs.getBoolean(6);
-				long period = rs.getLong(7);
-				byte[] secret = rs.getBytes(8);
-				long outgoing = rs.getLong(9);
-				long centre = rs.getLong(10);
-				byte[] bitmap = rs.getBytes(11);
-				secrets.add(new TemporarySecret(c, t, epoch, clockDiff, latency,
-						alice, period, secret, outgoing, centre, bitmap));
+				boolean alice = rs.getBoolean(4);
+				long period = rs.getLong(5);
+				byte[] secret = rs.getBytes(6);
+				long outgoing = rs.getLong(7);
+				long centre = rs.getLong(8);
+				byte[] bitmap = rs.getBytes(9);
+				secrets.add(new TemporarySecret(c, t, epoch,  alice, period,
+						secret, outgoing, centre, bitmap));
 			}
 			rs.close();
 			ps.close();
@@ -2265,11 +2362,11 @@ abstract class JdbcDatabase implements Database<Connection> {
 				ps.setBytes(2, a.getId().getBytes());
 				ps.addBatch();
 			}
-			int[] affectedBatch = ps.executeBatch();
-			if(affectedBatch.length != acks.size())
+			int[] batchAffected = ps.executeBatch();
+			if(batchAffected.length != acks.size())
 				throw new DbStateException();
-			for(int i = 0; i < affectedBatch.length; i++) {
-				if(affectedBatch[i] < 1) throw new DbStateException();
+			for(int i = 0; i < batchAffected.length; i++) {
+				if(batchAffected[i] < 1) throw new DbStateException();
 			}
 			ps.close();
 			return Collections.unmodifiableList(acks);
@@ -2280,6 +2377,29 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	public Map<TransportId, Long> getTransportLatencies(Connection txn)
+			throws DbException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT transportId, maxLatency FROM transports";
+			ps = txn.prepareStatement(sql);
+			rs = ps.executeQuery();
+			Map<TransportId, Long> latencies = new HashMap<TransportId, Long>();
+			while(rs.next()){
+				TransportId id = new TransportId(rs.getBytes(1));
+				latencies.put(id, rs.getLong(2));
+			}
+			rs.close();
+			ps.close();
+			return Collections.unmodifiableMap(latencies);
+		} catch(SQLException e) {
+			tryToClose(rs);
+			tryToClose(ps);
+			throw new DbException(e);
+		}
+	}
+
 	public Collection<TransportUpdate> getTransportUpdates(Connection txn,
 			ContactId c, long maxLatency) throws DbException {
 		long now = clock.currentTimeMillis();
@@ -2642,11 +2762,11 @@ abstract class JdbcDatabase implements Database<Connection> {
 				ps.setInt(2, c);
 				ps.addBatch();
 			}
-			int[] affectedBatch = ps.executeBatch();
-			if(affectedBatch.length != visible.size())
+			int[] batchAffected = ps.executeBatch();
+			if(batchAffected.length != visible.size())
 				throw new DbStateException();
-			for(int i = 0; i < affectedBatch.length; i++) {
-				if(affectedBatch[i] != 1) throw new DbStateException();
+			for(int i = 0; i < batchAffected.length; i++) {
+				if(batchAffected[i] != 1) throw new DbStateException();
 			}
 			ps.close();
 		} catch(SQLException e) {
@@ -2891,6 +3011,45 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	public void setRemoteProperties(Connection txn, ContactId c,
+			Map<TransportId, TransportProperties> p) throws DbException {
+		PreparedStatement ps = null;
+		try {
+			// Delete the existing properties, if any
+			String sql = "DELETE FROM contactTransportProperties"
+					+ " WHERE contactId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setInt(1, c.getInt());
+			ps.executeUpdate();
+			ps.close();
+			// Store the new properties
+			sql = "INSERT INTO contactTransportProperties"
+					+ " (contactId, transportId, key, value)"
+					+ " VALUES (?, ?, ?, ?)";
+			ps = txn.prepareStatement(sql);
+			ps.setInt(1, c.getInt());
+			int batchSize = 0;
+			for(Entry<TransportId, TransportProperties> e : p.entrySet()) {
+				ps.setBytes(2, e.getKey().getBytes());
+				for(Entry<String, String> e1 : e.getValue().entrySet()) {
+					ps.setString(3, e1.getKey());
+					ps.setString(4, e1.getValue());
+					ps.addBatch();
+					batchSize++;
+				}
+			}
+			int[] batchAffected = ps.executeBatch();
+			if(batchAffected.length != batchSize) throw new DbStateException();
+			for(int i = 0; i < batchAffected.length; i++) {
+				if(batchAffected[i] != 1) throw new DbStateException();
+			}
+			ps.close();
+		} catch(SQLException e) {
+			tryToClose(ps);
+			throw new DbException(e);
+		}
+	}
+
 	public void setRemoteProperties(Connection txn, ContactId c, TransportId t,
 			TransportProperties p, long version) throws DbException {
 		PreparedStatement ps = null;
@@ -3151,11 +3310,11 @@ abstract class JdbcDatabase implements Database<Connection> {
 				else ps.setNull(4, BINARY);
 				ps.addBatch();
 			}
-			int[] affectedBatch = ps.executeBatch();
-			if(affectedBatch.length != subs.size())
+			int[] batchAffected = ps.executeBatch();
+			if(batchAffected.length != subs.size())
 				throw new DbStateException();
-			for(int i = 0; i < affectedBatch.length; i++) {
-				if(affectedBatch[i] != 1) throw new DbStateException();
+			for(int i = 0; i < batchAffected.length; i++) {
+				if(batchAffected[i] != 1) throw new DbStateException();
 			}
 			ps.close();
 		} catch(SQLException e) {

briar-core/src/net/sf/briar/invitation/AliceConnector.java

@@ -8,16 +8,30 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.security.GeneralSecurityException;
+import java.util.Map;
 import java.util.logging.Logger;
 
+import net.sf.briar.api.Author;
+import net.sf.briar.api.AuthorFactory;
+import net.sf.briar.api.LocalAuthor;
+import net.sf.briar.api.TransportId;
+import net.sf.briar.api.TransportProperties;
 import net.sf.briar.api.clock.Clock;
 import net.sf.briar.api.crypto.CryptoComponent;
+import net.sf.briar.api.crypto.KeyManager;
+import net.sf.briar.api.crypto.PseudoRandom;
+import net.sf.briar.api.db.DatabaseComponent;
+import net.sf.briar.api.db.DbException;
 import net.sf.briar.api.plugins.duplex.DuplexPlugin;
 import net.sf.briar.api.plugins.duplex.DuplexTransportConnection;
 import net.sf.briar.api.serial.Reader;
 import net.sf.briar.api.serial.ReaderFactory;
 import net.sf.briar.api.serial.Writer;
 import net.sf.briar.api.serial.WriterFactory;
+import net.sf.briar.api.transport.ConnectionReader;
+import net.sf.briar.api.transport.ConnectionReaderFactory;
+import net.sf.briar.api.transport.ConnectionWriter;
+import net.sf.briar.api.transport.ConnectionWriterFactory;
 
 /** A connection thread for the peer being Alice in the invitation protocol. */
 class AliceConnector extends Connector {
@@ -25,11 +39,17 @@ class AliceConnector extends Connector {
 	private static final Logger LOG =
 			Logger.getLogger(AliceConnector.class.getName());
 
-	AliceConnector(CryptoComponent crypto, ReaderFactory readerFactory,
-			WriterFactory writerFactory, Clock clock, ConnectorGroup group,
-			DuplexPlugin plugin, int localCode, int remoteCode) {
-		super(crypto, readerFactory, writerFactory, clock, group, plugin,
-				crypto.getPseudoRandom(localCode, remoteCode));
+	AliceConnector(CryptoComponent crypto, DatabaseComponent db,
+			ReaderFactory readerFactory, WriterFactory writerFactory,
+			ConnectionReaderFactory connectionReaderFactory,
+			ConnectionWriterFactory connectionWriterFactory,
+			AuthorFactory authorFactory, KeyManager keyManager, Clock clock,
+			ConnectorGroup group, DuplexPlugin plugin, LocalAuthor localAuthor,
+			Map<TransportId, TransportProperties> localProps,
+			PseudoRandom random) {
+		super(crypto, db, readerFactory, writerFactory, connectionReaderFactory,
+				connectionWriterFactory, authorFactory, keyManager, clock,
+				group, plugin, localAuthor, localProps, random);
 	}
 
 	@Override
@@ -65,7 +85,7 @@ class AliceConnector extends Connector {
 			byte[] hash = receivePublicKeyHash(r);
 			sendPublicKey(w);
 			byte[] key = receivePublicKey(r);
-			secret = deriveSharedSecret(hash, key, true);
+			secret = deriveMasterSecret(hash, key, true);
 		} catch(IOException e) {
 			if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			tryToClose(conn, true);
@@ -76,9 +96,10 @@ class AliceConnector extends Connector {
 			return;
 		}
 		// The key agreement succeeded - derive the confirmation codes
-		if(LOG.isLoggable(INFO)) LOG.info(pluginName + " succeeded");
+		if(LOG.isLoggable(INFO)) LOG.info(pluginName + " agreement succeeded");
 		int[] codes = crypto.deriveConfirmationCodes(secret);
-		group.connectionSucceeded(codes[0], codes[1]);
+		int aliceCode = codes[0], bobCode = codes[1];
+		group.connectionSucceeded(aliceCode, bobCode);
 		// Exchange confirmation results
 		try {
 			sendConfirmation(w);
@@ -97,7 +118,59 @@ class AliceConnector extends Connector {
 			Thread.currentThread().interrupt();
 			return;
 		}
-		// That's all, folks!
+		// The timestamp is taken after exhanging confirmation results
+		long localTimestamp = clock.currentTimeMillis();
+		// Confirmation succeeded - upgrade to a secure connection
+		if(LOG.isLoggable(INFO))
+			LOG.info(pluginName + " confirmation succeeded");
+		ConnectionReader connectionReader =
+				connectionReaderFactory.createInvitationConnectionReader(in,
+						secret, false);
+		r = readerFactory.createReader(connectionReader.getInputStream());
+		ConnectionWriter connectionWriter =
+				connectionWriterFactory.createInvitationConnectionWriter(out,
+						secret, true);
+		w = writerFactory.createWriter(connectionWriter.getOutputStream());
+		// Derive the invitation nonces
+		byte[][] nonces = crypto.deriveInvitationNonces(secret);
+		byte[] aliceNonce = nonces[0], bobNonce = nonces[1];
+		// Exchange pseudonyms, signed nonces, timestamps and transports
+		Author remoteAuthor;
+		long remoteTimestamp;
+		Map<TransportId, TransportProperties> remoteProps;
+		try {
+			sendPseudonym(w, aliceNonce);
+			sendTimestamp(w, localTimestamp);
+			sendTransportProperties(w);
+			remoteAuthor = receivePseudonym(r, bobNonce);
+			remoteTimestamp = receiveTimestamp(r);
+			remoteProps = receiveTransportProperties(r);
+		} catch(GeneralSecurityException e) {
+			if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+			tryToClose(conn, true);
+			group.pseudonymExchangeFailed();
+			return;
+		} catch(IOException e) {
+			if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+			tryToClose(conn, true);
+			group.pseudonymExchangeFailed();
+			return;
+		}
+		// The epoch is the minimum of the peers' timestamps
+		long epoch = Math.min(localTimestamp, remoteTimestamp);
+		// Add the contact and store the transports
+		try {
+			addContact(remoteAuthor, remoteProps, secret, epoch, true);
+		} catch(DbException e) {
+			if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+			tryToClose(conn, true);
+			group.pseudonymExchangeFailed();
+			return;
+		}
+		// Pseudonym exchange succeeded
+		if(LOG.isLoggable(INFO))
+			LOG.info(pluginName + " pseudonym exchange succeeded");
+		group.pseudonymExchangeSucceeded(remoteAuthor);
 		tryToClose(conn, false);
 	}
 }

briar-core/src/net/sf/briar/invitation/BobConnector.java

@@ -8,16 +8,30 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.security.GeneralSecurityException;
+import java.util.Map;
 import java.util.logging.Logger;
 
+import net.sf.briar.api.Author;
+import net.sf.briar.api.AuthorFactory;
+import net.sf.briar.api.LocalAuthor;
+import net.sf.briar.api.TransportId;
+import net.sf.briar.api.TransportProperties;
 import net.sf.briar.api.clock.Clock;
 import net.sf.briar.api.crypto.CryptoComponent;
+import net.sf.briar.api.crypto.KeyManager;
+import net.sf.briar.api.crypto.PseudoRandom;
+import net.sf.briar.api.db.DatabaseComponent;
+import net.sf.briar.api.db.DbException;
 import net.sf.briar.api.plugins.duplex.DuplexPlugin;
 import net.sf.briar.api.plugins.duplex.DuplexTransportConnection;
 import net.sf.briar.api.serial.Reader;
 import net.sf.briar.api.serial.ReaderFactory;
 import net.sf.briar.api.serial.Writer;
 import net.sf.briar.api.serial.WriterFactory;
+import net.sf.briar.api.transport.ConnectionReader;
+import net.sf.briar.api.transport.ConnectionReaderFactory;
+import net.sf.briar.api.transport.ConnectionWriter;
+import net.sf.briar.api.transport.ConnectionWriterFactory;
 
 /** A connection thread for the peer being Bob in the invitation protocol. */
 class BobConnector extends Connector {
@@ -25,11 +39,17 @@ class BobConnector extends Connector {
 	private static final Logger LOG =
 			Logger.getLogger(BobConnector.class.getName());
 
-	BobConnector(CryptoComponent crypto, ReaderFactory readerFactory,
-			WriterFactory writerFactory, Clock clock, ConnectorGroup group,
-			DuplexPlugin plugin, int localCode, int remoteCode) {
-		super(crypto, readerFactory, writerFactory, clock, group, plugin,
-				crypto.getPseudoRandom(remoteCode, localCode));
+	BobConnector(CryptoComponent crypto, DatabaseComponent db,
+			ReaderFactory readerFactory, WriterFactory writerFactory,
+			ConnectionReaderFactory connectionReaderFactory,
+			ConnectionWriterFactory connectionWriterFactory,
+			AuthorFactory authorFactory, KeyManager keyManager, Clock clock,
+			ConnectorGroup group, DuplexPlugin plugin, LocalAuthor localAuthor,
+			Map<TransportId, TransportProperties> localProps,
+			PseudoRandom random) {
+		super(crypto, db, readerFactory, writerFactory, connectionReaderFactory,
+				connectionWriterFactory, authorFactory, keyManager, clock,
+				group, plugin, localAuthor, localProps, random);
 	}
 
 	@Override
@@ -65,7 +85,7 @@ class BobConnector extends Connector {
 			sendPublicKeyHash(w);
 			byte[] key = receivePublicKey(r);
 			sendPublicKey(w);
-			secret = deriveSharedSecret(hash, key, false);
+			secret = deriveMasterSecret(hash, key, false);
 		} catch(IOException e) {
 			if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			tryToClose(conn, true);
@@ -76,14 +96,15 @@ class BobConnector extends Connector {
 			return;
 		}
 		// The key agreement succeeded - derive the confirmation codes
-		if(LOG.isLoggable(INFO)) LOG.info(pluginName + " succeeded");
+		if(LOG.isLoggable(INFO)) LOG.info(pluginName + " agreement succeeded");
 		int[] codes = crypto.deriveConfirmationCodes(secret);
-		group.connectionSucceeded(codes[1], codes[0]);
+		int aliceCode = codes[0], bobCode = codes[1];
+		group.connectionSucceeded(bobCode, aliceCode);
 		// Exchange confirmation results
 		try {
-			sendConfirmation(w);
 			if(receiveConfirmation(r)) group.remoteConfirmationSucceeded();
 			else group.remoteConfirmationFailed();
+			sendConfirmation(w);
 		} catch(IOException e) {
 			if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			tryToClose(conn, true);
@@ -97,7 +118,59 @@ class BobConnector extends Connector {
 			Thread.currentThread().interrupt();
 			return;
 		}
-		// That's all, folks!
+		// The timestamp is taken after exhanging confirmation results
+		long localTimestamp = clock.currentTimeMillis();
+		// Confirmation succeeded - upgrade to a secure connection
+		if(LOG.isLoggable(INFO))
+			LOG.info(pluginName + " confirmation succeeded");
+		ConnectionReader connectionReader =
+				connectionReaderFactory.createInvitationConnectionReader(in,
+						secret, true);
+		r = readerFactory.createReader(connectionReader.getInputStream());
+		ConnectionWriter connectionWriter =
+				connectionWriterFactory.createInvitationConnectionWriter(out,
+						secret, false);
+		w = writerFactory.createWriter(connectionWriter.getOutputStream());
+		// Derive the nonces
+		byte[][] nonces = crypto.deriveInvitationNonces(secret);
+		byte[] aliceNonce = nonces[0], bobNonce = nonces[1];
+		// Exchange pseudonyms, signed nonces, timestamps and transports
+		Author remoteAuthor;
+		long remoteTimestamp;
+		Map<TransportId, TransportProperties> remoteProps;
+		try {
+			remoteAuthor = receivePseudonym(r, aliceNonce);
+			remoteTimestamp = receiveTimestamp(r);
+			remoteProps = receiveTransportProperties(r);
+			sendPseudonym(w, bobNonce);
+			sendTimestamp(w, localTimestamp);
+			sendTransportProperties(w);
+		} catch(GeneralSecurityException e) {
+			if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+			tryToClose(conn, true);
+			group.pseudonymExchangeFailed();
+			return;
+		} catch(IOException e) {
+			if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+			tryToClose(conn, true);
+			group.pseudonymExchangeFailed();
+			return;
+		}
+		// The epoch is the minimum of the peers' timestamps
+		long epoch = Math.min(localTimestamp, remoteTimestamp);
+		// Add the contact and store the transports
+		try {
+			addContact(remoteAuthor, remoteProps, secret, epoch, true);
+		} catch(DbException e) {
+			if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+			tryToClose(conn, true);
+			group.pseudonymExchangeFailed();
+			return;
+		}
+		// Pseudonym exchange succeeded
+		if(LOG.isLoggable(INFO))
+			LOG.info(pluginName + " pseudonym exchange succeeded");
+		group.pseudonymExchangeSucceeded(remoteAuthor);
 		tryToClose(conn, false);
 	}
 }

briar-core/src/net/sf/briar/invitation/Connector.java

@@ -2,28 +2,53 @@ package net.sf.briar.invitation;
 
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
+import static net.sf.briar.api.messaging.MessagingConstants.MAX_AUTHOR_NAME_LENGTH;
+import static net.sf.briar.api.messaging.MessagingConstants.MAX_PROPERTY_LENGTH;
+import static net.sf.briar.api.messaging.MessagingConstants.MAX_PUBLIC_KEY_LENGTH;
+import static net.sf.briar.api.messaging.MessagingConstants.MAX_SIGNATURE_LENGTH;
 import static net.sf.briar.api.plugins.InvitationConstants.CONNECTION_TIMEOUT;
 import static net.sf.briar.api.plugins.InvitationConstants.HASH_LENGTH;
-import static net.sf.briar.api.plugins.InvitationConstants.MAX_PUBLIC_KEY_LENGTH;
 
 import java.io.IOException;
 import java.security.GeneralSecurityException;
 import java.security.KeyPair;
+import java.security.Signature;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
 import java.util.logging.Logger;
 
+import net.sf.briar.api.Author;
+import net.sf.briar.api.AuthorFactory;
+import net.sf.briar.api.ContactId;
 import net.sf.briar.api.FormatException;
+import net.sf.briar.api.LocalAuthor;
+import net.sf.briar.api.TransportId;
+import net.sf.briar.api.TransportProperties;
+import net.sf.briar.api.UniqueId;
 import net.sf.briar.api.clock.Clock;
 import net.sf.briar.api.crypto.CryptoComponent;
+import net.sf.briar.api.crypto.KeyManager;
 import net.sf.briar.api.crypto.KeyParser;
 import net.sf.briar.api.crypto.MessageDigest;
 import net.sf.briar.api.crypto.PseudoRandom;
+import net.sf.briar.api.db.DatabaseComponent;
+import net.sf.briar.api.db.DbException;
+import net.sf.briar.api.db.NoSuchTransportException;
 import net.sf.briar.api.plugins.duplex.DuplexPlugin;
 import net.sf.briar.api.plugins.duplex.DuplexTransportConnection;
 import net.sf.briar.api.serial.Reader;
 import net.sf.briar.api.serial.ReaderFactory;
 import net.sf.briar.api.serial.Writer;
 import net.sf.briar.api.serial.WriterFactory;
+import net.sf.briar.api.transport.ConnectionReaderFactory;
+import net.sf.briar.api.transport.ConnectionWriterFactory;
+import net.sf.briar.api.transport.Endpoint;
 
 abstract class Connector extends Thread {
 
@@ -31,11 +56,18 @@ abstract class Connector extends Thread {
 			Logger.getLogger(Connector.class.getName());
 
 	protected final CryptoComponent crypto;
+	protected final DatabaseComponent db;
 	protected final ReaderFactory readerFactory;
 	protected final WriterFactory writerFactory;
+	protected final ConnectionReaderFactory connectionReaderFactory;
+	protected final ConnectionWriterFactory connectionWriterFactory;
+	protected final AuthorFactory authorFactory;
+	protected final KeyManager keyManager;
 	protected final Clock clock;
 	protected final ConnectorGroup group;
 	protected final DuplexPlugin plugin;
+	protected final LocalAuthor localAuthor;
+	protected final Map<TransportId, TransportProperties> localProps;
 	protected final PseudoRandom random;
 	protected final String pluginName;
 
@@ -43,16 +75,28 @@ abstract class Connector extends Thread {
 	private final KeyParser keyParser;
 	private final MessageDigest messageDigest;
 
-	Connector(CryptoComponent crypto, ReaderFactory readerFactory,
-			WriterFactory writerFactory, Clock clock, ConnectorGroup group,
-			DuplexPlugin plugin, PseudoRandom random) {
+	Connector(CryptoComponent crypto, DatabaseComponent db,
+			ReaderFactory readerFactory, WriterFactory writerFactory,
+			ConnectionReaderFactory connectionReaderFactory,
+			ConnectionWriterFactory connectionWriterFactory,
+			AuthorFactory authorFactory, KeyManager keyManager, Clock clock,
+			ConnectorGroup group, DuplexPlugin plugin, LocalAuthor localAuthor,
+			Map<TransportId, TransportProperties> localProps,
+			PseudoRandom random) {
 		super("Connector");
 		this.crypto = crypto;
+		this.db = db;
 		this.readerFactory = readerFactory;
 		this.writerFactory = writerFactory;
+		this.connectionReaderFactory = connectionReaderFactory;
+		this.connectionWriterFactory = connectionWriterFactory;
+		this.authorFactory = authorFactory;
+		this.keyManager = keyManager;
 		this.clock = clock;
 		this.group = group;
 		this.plugin = plugin;
+		this.localAuthor = localAuthor;
+		this.localProps = localProps;
 		this.random = random;
 		pluginName = plugin.getClass().getName();
 		keyPair = crypto.generateAgreementKeyPair();
@@ -87,16 +131,6 @@ abstract class Connector extends Thread {
 		}
 	}
 
-	protected void tryToClose(DuplexTransportConnection conn,
-			boolean exception) {
-		try {
-			if(LOG.isLoggable(INFO)) LOG.info("Closing connection");
-			conn.dispose(exception, true);
-		} catch(IOException e) {
-			if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		}
-	}
-
 	protected void sendPublicKeyHash(Writer w) throws IOException {
 		w.writeBytes(messageDigest.digest(keyPair.getPublic().getEncoded()));
 		w.flush();
@@ -116,18 +150,15 @@ abstract class Connector extends Thread {
 		if(LOG.isLoggable(INFO)) LOG.info(pluginName + " sent key");
 	}
 
-	protected byte[] receivePublicKey(Reader r) throws IOException {
+	protected byte[] receivePublicKey(Reader r) throws GeneralSecurityException,
+	IOException {
 		byte[] b = r.readBytes(MAX_PUBLIC_KEY_LENGTH);
-		try {
-			keyParser.parsePublicKey(b);
-		} catch(GeneralSecurityException e) {
-			throw new FormatException();
-		}
+		keyParser.parsePublicKey(b);
 		if(LOG.isLoggable(INFO)) LOG.info(pluginName + " received key");
 		return b;
 	}
 
-	protected byte[] deriveSharedSecret(byte[] hash, byte[] key, boolean alice)
+	protected byte[] deriveMasterSecret(byte[] hash, byte[] key, boolean alice)
 			throws GeneralSecurityException {
 		// Check that the hash matches the key
 		if(!Arrays.equals(hash, messageDigest.digest(key))) {
@@ -135,16 +166,16 @@ abstract class Connector extends Thread {
 				LOG.info(pluginName + " hash does not match key");
 			throw new GeneralSecurityException();
 		}
-		//  Derive the shared secret
-		return crypto.deriveInitialSecret(key, keyPair, alice);
+		//  Derive the master secret
+		return crypto.deriveMasterSecret(key, keyPair, alice);
 	}
 
 	protected void sendConfirmation(Writer w) throws IOException,
 	InterruptedException {
 		boolean matched = group.waitForLocalConfirmationResult();
-		if(LOG.isLoggable(INFO)) LOG.info(pluginName + " sent confirmation");
 		w.writeBoolean(matched);
 		w.flush();
+		if(LOG.isLoggable(INFO)) LOG.info(pluginName + " sent confirmation");
 	}
 
 	protected boolean receiveConfirmation(Reader r) throws IOException {
@@ -153,4 +184,137 @@ abstract class Connector extends Thread {
 			LOG.info(pluginName + " received confirmation");
 		return matched;
 	}
+
+	protected void sendPseudonym(Writer w, byte[] nonce)
+			throws GeneralSecurityException, IOException {
+		// Sign the nonce
+		Signature signature = crypto.getSignature();
+		KeyParser keyParser = crypto.getSignatureKeyParser();
+		byte[] privateKey = localAuthor.getPrivateKey();
+		signature.initSign(keyParser.parsePrivateKey(privateKey));
+		signature.update(nonce);
+		byte[] sig = signature.sign();
+		// Write the name, public key and signature
+		w.writeString(localAuthor.getName());
+		w.writeBytes(localAuthor.getPublicKey());
+		w.writeBytes(sig);
+		w.flush();
+		if(LOG.isLoggable(INFO)) LOG.info(pluginName + " sent pseudonym");
+	}
+
+	protected Author receivePseudonym(Reader r, byte[] nonce)
+			throws GeneralSecurityException, IOException {
+		// Read the name, public key and signature
+		String name = r.readString(MAX_AUTHOR_NAME_LENGTH);
+		byte[] publicKey = r.readBytes(MAX_PUBLIC_KEY_LENGTH);
+		byte[] sig = r.readBytes(MAX_SIGNATURE_LENGTH);
+		if(LOG.isLoggable(INFO)) LOG.info(pluginName + " received pseudonym");
+		// Verify the signature
+		Signature signature = crypto.getSignature();
+		KeyParser keyParser = crypto.getSignatureKeyParser();
+		signature.initVerify(keyParser.parsePublicKey(publicKey));
+		signature.update(nonce);
+		if(!signature.verify(sig)) {
+			if(LOG.isLoggable(INFO))
+				LOG.info(pluginName + " invalid signature");
+			throw new GeneralSecurityException();
+		}
+		return authorFactory.createAuthor(name, publicKey);
+	}
+
+	protected void sendTimestamp(Writer w, long timestamp) throws IOException {
+		w.writeInt64(timestamp);
+		w.flush();
+		if(LOG.isLoggable(INFO)) LOG.info(pluginName + " sent timestamp");
+	}
+
+	protected long receiveTimestamp(Reader r) throws IOException {
+		long timestamp = r.readInt64();
+		if(timestamp < 0) throw new FormatException();
+		if(LOG.isLoggable(INFO)) LOG.info(pluginName + " received timestamp");
+		return timestamp;
+	}
+
+	protected void sendTransportProperties(Writer w) throws IOException {
+		w.writeListStart();
+		for(Entry<TransportId, TransportProperties> e : localProps.entrySet()) {
+			w.writeBytes(e.getKey().getBytes());
+			w.writeMap(e.getValue());
+		}
+		w.writeListEnd();
+		w.flush();
+		if(LOG.isLoggable(INFO))
+			LOG.info(pluginName + " sent transport properties");
+	}
+
+	protected Map<TransportId, TransportProperties> receiveTransportProperties(
+			Reader r) throws IOException {
+		Map<TransportId, TransportProperties> remoteProps =
+				new HashMap<TransportId, TransportProperties>();
+		r.readListStart();
+		while(!r.hasListEnd()) {
+			byte[] b = r.readBytes(UniqueId.LENGTH);
+			if(b.length != UniqueId.LENGTH) throw new FormatException();
+			TransportId id = new TransportId(b);
+			r.setMaxStringLength(MAX_PROPERTY_LENGTH);
+			Map<String, String> p = r.readMap(String.class, String.class);
+			r.resetMaxStringLength();
+			remoteProps.put(id, new TransportProperties(p));
+		}
+		r.readListEnd();
+		if(LOG.isLoggable(INFO))
+			LOG.info(pluginName + " received transport properties");
+		return remoteProps;
+	}
+
+	protected void addContact(Author remoteAuthor,
+			Map<TransportId, TransportProperties> remoteProps,  byte[] secret,
+			long epoch, boolean alice) throws DbException {
+		// Add the contact to the database
+		ContactId c = db.addContact(remoteAuthor, localAuthor.getId());
+		// Store the remote transport properties
+		db.setRemoteProperties(c, remoteProps);
+		// Create an endpoint for each transport shared with the contact
+		List<TransportId> ids = new ArrayList<TransportId>();
+		for(TransportId id : localProps.keySet())
+			if(remoteProps.containsKey(id)) ids.add(id);
+		// Assign indices to the transports in a deterministic way
+		Collections.sort(ids, TransportIdComparator.INSTANCE);
+		int size = ids.size();
+		for(int i = 0; i < size; i++) {
+			Endpoint ep = new Endpoint(c, ids.get(i), epoch, alice);
+			try {
+				db.addEndpoint(ep);
+			} catch(NoSuchTransportException e) {
+				continue;
+			}
+			keyManager.endpointAdded(ep, crypto.deriveInitialSecret(secret, i));
+		}
+	}
+
+	protected void tryToClose(DuplexTransportConnection conn,
+			boolean exception) {
+		try {
+			if(LOG.isLoggable(INFO)) LOG.info("Closing connection");
+			conn.dispose(exception, true);
+		} catch(IOException e) {
+			if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+		}
+	}
+
+	private static class TransportIdComparator
+	implements Comparator<TransportId> {
+
+		private static final TransportIdComparator INSTANCE =
+				new TransportIdComparator();
+
+		public int compare(TransportId t1, TransportId t2) {
+			byte[] b1 = t1.getBytes(), b2 = t2.getBytes();
+			for(int i = 0; i < UniqueId.LENGTH; i++) {
+				if((b1[i] & 0xff) < (b2[i] & 0xff)) return -1;
+				if((b1[i] & 0xff) > (b2[i] & 0xff)) return 1;
+			}
+			return 0;
+		}
+	}
 }

briar-core/src/net/sf/briar/invitation/ConnectorGroup.java

@@ -6,13 +6,24 @@ import static net.sf.briar.api.plugins.InvitationConstants.CONFIRMATION_TIMEOUT;
 
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Map;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
 
+import net.sf.briar.api.Author;
+import net.sf.briar.api.AuthorFactory;
+import net.sf.briar.api.AuthorId;
+import net.sf.briar.api.LocalAuthor;
+import net.sf.briar.api.TransportId;
+import net.sf.briar.api.TransportProperties;
 import net.sf.briar.api.clock.Clock;
 import net.sf.briar.api.crypto.CryptoComponent;
+import net.sf.briar.api.crypto.KeyManager;
+import net.sf.briar.api.crypto.PseudoRandom;
+import net.sf.briar.api.db.DatabaseComponent;
+import net.sf.briar.api.db.DbException;
 import net.sf.briar.api.invitation.InvitationListener;
 import net.sf.briar.api.invitation.InvitationState;
 import net.sf.briar.api.invitation.InvitationTask;
@@ -20,6 +31,8 @@ import net.sf.briar.api.plugins.PluginManager;
 import net.sf.briar.api.plugins.duplex.DuplexPlugin;
 import net.sf.briar.api.serial.ReaderFactory;
 import net.sf.briar.api.serial.WriterFactory;
+import net.sf.briar.api.transport.ConnectionReaderFactory;
+import net.sf.briar.api.transport.ConnectionWriterFactory;
 
 /** A task consisting of one or more parallel connection attempts. */
 class ConnectorGroup extends Thread implements InvitationTask {
@@ -28,10 +41,16 @@ class ConnectorGroup extends Thread implements InvitationTask {
 			Logger.getLogger(ConnectorGroup.class.getName());
 
 	private final CryptoComponent crypto;
+	private final DatabaseComponent db;
 	private final ReaderFactory readerFactory;
 	private final WriterFactory writerFactory;
+	private final ConnectionReaderFactory connectionReaderFactory;
+	private final ConnectionWriterFactory connectionWriterFactory;
+	private final AuthorFactory authorFactory;
+	private final KeyManager keyManager;
 	private final Clock clock;
 	private final PluginManager pluginManager;
+	private final AuthorId localAuthorId;
 	private final int localInvitationCode, remoteInvitationCode;
 	private final Collection<InvitationListener> listeners;
 	private final AtomicBoolean connected;
@@ -47,17 +66,27 @@ class ConnectorGroup extends Thread implements InvitationTask {
 	private boolean connectionFailed = false;
 	private boolean localCompared = false, remoteCompared = false;
 	private boolean localMatched = false, remoteMatched = false;
+	private String remoteName = null;
 
-	ConnectorGroup(CryptoComponent crypto, ReaderFactory readerFactory,
-			WriterFactory writerFactory, Clock clock,
-			PluginManager pluginManager, int localInvitationCode,
-			int remoteInvitationCode) {
+	ConnectorGroup(CryptoComponent crypto, DatabaseComponent db,
+			ReaderFactory readerFactory, WriterFactory writerFactory,
+			ConnectionReaderFactory connectionReaderFactory,
+			ConnectionWriterFactory connectionWriterFactory,
+			AuthorFactory authorFactory, KeyManager keyManager, Clock clock,
+			PluginManager pluginManager, AuthorId localAuthorId,
+			int localInvitationCode, int remoteInvitationCode) {
 		super("ConnectorGroup");
 		this.crypto = crypto;
+		this.db = db;
 		this.readerFactory = readerFactory;
 		this.writerFactory = writerFactory;
+		this.connectionReaderFactory = connectionReaderFactory;
+		this.connectionWriterFactory = connectionWriterFactory;
+		this.authorFactory = authorFactory;
+		this.keyManager = keyManager;
 		this.clock = clock;
 		this.pluginManager = pluginManager;
+		this.localAuthorId = localAuthorId;
 		this.localInvitationCode = localInvitationCode;
 		this.remoteInvitationCode = remoteInvitationCode;
 		listeners = new CopyOnWriteArrayList<InvitationListener>();
@@ -68,8 +97,9 @@ class ConnectorGroup extends Thread implements InvitationTask {
 	public synchronized InvitationState addListener(InvitationListener l) {
 		listeners.add(l);
 		return new InvitationState(localInvitationCode, remoteInvitationCode,
-				localConfirmationCode, remoteConfirmationCode, connectionFailed,
-				localCompared, remoteCompared, localMatched, remoteMatched);
+				localConfirmationCode, remoteConfirmationCode,
+				connectionFailed, localCompared, remoteCompared, localMatched,
+				remoteMatched, remoteName);
 	}
 
 	public void removeListener(InvitationListener l) {
@@ -82,22 +112,34 @@ class ConnectorGroup extends Thread implements InvitationTask {
 
 	@Override
 	public void run() {
+		LocalAuthor localAuthor;
+		Map<TransportId, TransportProperties> localProps;
+		// Load the local pseudonym and transport properties
+		try {
+			localAuthor = db.getLocalAuthor(localAuthorId);
+			localProps = db.getLocalProperties();
+		} catch(DbException e) {
+			if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+			synchronized(this) {
+				connectionFailed = true;
+			}
+			for(InvitationListener l : listeners) l.connectionFailed();
+			return;
+		}
 		// Start the connection threads
 		Collection<Connector> connectors = new ArrayList<Connector>();
 		// Alice is the party with the smaller invitation code
 		if(localInvitationCode < remoteInvitationCode) {
 			for(DuplexPlugin plugin : pluginManager.getInvitationPlugins()) {
-				Connector c = new AliceConnector(crypto, readerFactory,
-						writerFactory, clock, this, plugin, localInvitationCode,
-						remoteInvitationCode);
+				Connector c = createAliceConnector(plugin, localAuthor,
+						localProps);
 				connectors.add(c);
 				c.start();
 			}
 		} else {
 			for(DuplexPlugin plugin: pluginManager.getInvitationPlugins()) {
-				Connector c = (new BobConnector(crypto, readerFactory,
-						writerFactory, clock, this, plugin, localInvitationCode,
-						remoteInvitationCode));
+				Connector c = createBobConnector(plugin, localAuthor,
+						localProps);
 				connectors.add(c);
 				c.start();
 			}
@@ -118,6 +160,28 @@ class ConnectorGroup extends Thread implements InvitationTask {
 		}
 	}
 
+	private Connector createAliceConnector(DuplexPlugin plugin,
+			LocalAuthor localAuthor,
+			Map<TransportId, TransportProperties> localProps) {
+		PseudoRandom random = crypto.getPseudoRandom(localInvitationCode,
+				remoteInvitationCode);
+		return new AliceConnector(crypto, db, readerFactory, writerFactory,
+				connectionReaderFactory, connectionWriterFactory, authorFactory,
+				keyManager, clock, this, plugin, localAuthor, localProps,
+				random);
+	}
+
+	private Connector createBobConnector(DuplexPlugin plugin,
+			LocalAuthor localAuthor,
+			Map<TransportId, TransportProperties> localProps) {
+		PseudoRandom random = crypto.getPseudoRandom(remoteInvitationCode,
+				localInvitationCode);
+		return new BobConnector(crypto, db, readerFactory, writerFactory,
+				connectionReaderFactory, connectionWriterFactory, authorFactory,
+				keyManager, clock, this, plugin, localAuthor, localProps,
+				random);
+	}
+
 	public void localConfirmationSucceeded() {
 		synchronized(this) {
 			localCompared = true;
@@ -167,4 +231,17 @@ class ConnectorGroup extends Thread implements InvitationTask {
 			return localMatched;
 		}
 	}
+
+	void pseudonymExchangeSucceeded(Author remoteAuthor) {
+		String name = remoteAuthor.getName();
+		synchronized(this) {
+			remoteName = name;
+		}
+		for(InvitationListener l : listeners)
+			l.pseudonymExchangeSucceeded(name);
+	}
+
+	void pseudonymExchangeFailed() {
+		for(InvitationListener l : listeners) l.pseudonymExchangeFailed();
+	}
 }

briar-core/src/net/sf/briar/invitation/InvitationTaskFactoryImpl.java

@@ -1,36 +1,58 @@
 package net.sf.briar.invitation;
 
+import net.sf.briar.api.AuthorFactory;
+import net.sf.briar.api.AuthorId;
 import net.sf.briar.api.clock.Clock;
 import net.sf.briar.api.crypto.CryptoComponent;
+import net.sf.briar.api.crypto.KeyManager;
+import net.sf.briar.api.db.DatabaseComponent;
 import net.sf.briar.api.invitation.InvitationTask;
 import net.sf.briar.api.invitation.InvitationTaskFactory;
 import net.sf.briar.api.plugins.PluginManager;
 import net.sf.briar.api.serial.ReaderFactory;
 import net.sf.briar.api.serial.WriterFactory;
+import net.sf.briar.api.transport.ConnectionReaderFactory;
+import net.sf.briar.api.transport.ConnectionWriterFactory;
 
 import com.google.inject.Inject;
 
 class InvitationTaskFactoryImpl implements InvitationTaskFactory {
 
 	private final CryptoComponent crypto;
+	private final DatabaseComponent db;
 	private final ReaderFactory readerFactory;
 	private final WriterFactory writerFactory;
+	private final ConnectionReaderFactory connectionReaderFactory;
+	private final ConnectionWriterFactory connectionWriterFactory;
+	private final AuthorFactory authorFactory;
+	private final KeyManager keyManager;
 	private final Clock clock;
 	private final PluginManager pluginManager;
 
 	@Inject
-	InvitationTaskFactoryImpl(CryptoComponent crypto,
+	InvitationTaskFactoryImpl(CryptoComponent crypto, DatabaseComponent db,
 			ReaderFactory readerFactory, WriterFactory writerFactory,
-			Clock clock, PluginManager pluginManager) {
+			ConnectionReaderFactory connectionReaderFactory,
+			ConnectionWriterFactory connectionWriterFactory,
+			AuthorFactory authorFactory, KeyManager keyManager, Clock clock,
+			PluginManager pluginManager) {
 		this.crypto = crypto;
+		this.db = db;
 		this.readerFactory = readerFactory;
 		this.writerFactory = writerFactory;
+		this.connectionReaderFactory = connectionReaderFactory;
+		this.connectionWriterFactory = connectionWriterFactory;
+		this.authorFactory = authorFactory;
+		this.keyManager = keyManager;
 		this.clock = clock;
 		this.pluginManager = pluginManager;
 	}
 
-	public InvitationTask createTask(int localCode, int remoteCode) {
-		return new ConnectorGroup(crypto, readerFactory, writerFactory, clock,
-				pluginManager, localCode, remoteCode);
+	public InvitationTask createTask(AuthorId localAuthorId, int localCode,
+			int remoteCode) {
+		return new ConnectorGroup(crypto, db, readerFactory, writerFactory,
+				connectionReaderFactory, connectionWriterFactory,
+				authorFactory, keyManager, clock, pluginManager, localAuthorId,
+				localCode, remoteCode);
 	}
 }

briar-core/src/net/sf/briar/messaging/AuthorFactoryImpl.java

@@ -5,11 +5,11 @@ import static net.sf.briar.api.messaging.Types.AUTHOR;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 
+import net.sf.briar.api.Author;
+import net.sf.briar.api.AuthorFactory;
+import net.sf.briar.api.AuthorId;
 import net.sf.briar.api.crypto.CryptoComponent;
 import net.sf.briar.api.crypto.MessageDigest;
-import net.sf.briar.api.messaging.Author;
-import net.sf.briar.api.messaging.AuthorFactory;
-import net.sf.briar.api.messaging.AuthorId;
 import net.sf.briar.api.serial.Writer;
 import net.sf.briar.api.serial.WriterFactory;
 

briar-core/src/net/sf/briar/messaging/AuthorReader.java

@@ -6,10 +6,10 @@ import static net.sf.briar.api.messaging.Types.AUTHOR;
 
 import java.io.IOException;
 
+import net.sf.briar.api.Author;
+import net.sf.briar.api.AuthorId;
 import net.sf.briar.api.crypto.CryptoComponent;
 import net.sf.briar.api.crypto.MessageDigest;
-import net.sf.briar.api.messaging.Author;
-import net.sf.briar.api.messaging.AuthorId;
 import net.sf.briar.api.serial.DigestingConsumer;
 import net.sf.briar.api.serial.Reader;
 import net.sf.briar.api.serial.StructReader;

briar-core/src/net/sf/briar/messaging/MessageFactoryImpl.java

@@ -20,10 +20,10 @@ import java.security.PrivateKey;
 import java.security.SecureRandom;
 import java.security.Signature;
 
+import net.sf.briar.api.Author;
 import net.sf.briar.api.clock.Clock;
 import net.sf.briar.api.crypto.CryptoComponent;
 import net.sf.briar.api.crypto.MessageDigest;
-import net.sf.briar.api.messaging.Author;
 import net.sf.briar.api.messaging.Group;
 import net.sf.briar.api.messaging.Message;
 import net.sf.briar.api.messaging.MessageFactory;

briar-core/src/net/sf/briar/messaging/MessageImpl.java

@@ -1,7 +1,7 @@
 package net.sf.briar.messaging;
 
 import static net.sf.briar.api.messaging.MessagingConstants.MAX_BODY_LENGTH;
-import net.sf.briar.api.messaging.Author;
+import net.sf.briar.api.Author;
 import net.sf.briar.api.messaging.Group;
 import net.sf.briar.api.messaging.Message;
 import net.sf.briar.api.messaging.MessageId;

briar-core/src/net/sf/briar/messaging/MessageReader.java

@@ -13,11 +13,11 @@ import java.nio.ByteBuffer;
 import java.nio.charset.Charset;
 import java.nio.charset.CharsetDecoder;
 
+import net.sf.briar.api.Author;
 import net.sf.briar.api.FormatException;
-import net.sf.briar.api.messaging.Author;
+import net.sf.briar.api.UniqueId;
 import net.sf.briar.api.messaging.Group;
 import net.sf.briar.api.messaging.MessageId;
-import net.sf.briar.api.messaging.UniqueId;
 import net.sf.briar.api.messaging.UnverifiedMessage;
 import net.sf.briar.api.serial.CopyingConsumer;
 import net.sf.briar.api.serial.CountingConsumer;

briar-core/src/net/sf/briar/messaging/MessageVerifierImpl.java

@@ -4,10 +4,10 @@ import java.security.GeneralSecurityException;
 import java.security.PublicKey;
 import java.security.Signature;
 
+import net.sf.briar.api.Author;
 import net.sf.briar.api.crypto.CryptoComponent;
 import net.sf.briar.api.crypto.KeyParser;
 import net.sf.briar.api.crypto.MessageDigest;
-import net.sf.briar.api.messaging.Author;
 import net.sf.briar.api.messaging.Group;
 import net.sf.briar.api.messaging.Message;
 import net.sf.briar.api.messaging.MessageId;

briar-core/src/net/sf/briar/messaging/MessagingModule.java

@@ -1,8 +1,8 @@
 package net.sf.briar.messaging;
 
+import net.sf.briar.api.Author;
+import net.sf.briar.api.AuthorFactory;
 import net.sf.briar.api.crypto.CryptoComponent;
-import net.sf.briar.api.messaging.Author;
-import net.sf.briar.api.messaging.AuthorFactory;
 import net.sf.briar.api.messaging.Group;
 import net.sf.briar.api.messaging.GroupFactory;
 import net.sf.briar.api.messaging.MessageFactory;

briar-core/src/net/sf/briar/messaging/PacketReaderImpl.java

@@ -24,7 +24,9 @@ import java.util.Map;
 
 import net.sf.briar.api.Bytes;
 import net.sf.briar.api.FormatException;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.TransportProperties;
+import net.sf.briar.api.UniqueId;
 import net.sf.briar.api.messaging.Ack;
 import net.sf.briar.api.messaging.MessageId;
 import net.sf.briar.api.messaging.Offer;
@@ -35,9 +37,7 @@ import net.sf.briar.api.messaging.RetentionUpdate;
 import net.sf.briar.api.messaging.SubscriptionAck;
 import net.sf.briar.api.messaging.SubscriptionUpdate;
 import net.sf.briar.api.messaging.TransportAck;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.messaging.TransportUpdate;
-import net.sf.briar.api.messaging.UniqueId;
 import net.sf.briar.api.messaging.UnverifiedMessage;
 import net.sf.briar.api.serial.Consumer;
 import net.sf.briar.api.serial.CountingConsumer;

briar-core/src/net/sf/briar/messaging/duplex/DuplexConnection.java

@@ -2,8 +2,8 @@ package net.sf.briar.messaging.duplex;
 
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
-import static net.sf.briar.api.Rating.GOOD;
 import static net.sf.briar.api.messaging.MessagingConstants.MAX_PACKET_LENGTH;
+import static net.sf.briar.api.messaging.Rating.GOOD;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -23,6 +23,7 @@ import java.util.logging.Logger;
 
 import net.sf.briar.api.ContactId;
 import net.sf.briar.api.FormatException;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.crypto.CryptoExecutor;
 import net.sf.briar.api.db.DatabaseComponent;
 import net.sf.briar.api.db.DatabaseExecutor;
@@ -55,7 +56,6 @@ import net.sf.briar.api.messaging.RetentionUpdate;
 import net.sf.briar.api.messaging.SubscriptionAck;
 import net.sf.briar.api.messaging.SubscriptionUpdate;
 import net.sf.briar.api.messaging.TransportAck;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.messaging.TransportUpdate;
 import net.sf.briar.api.messaging.UnverifiedMessage;
 import net.sf.briar.api.plugins.duplex.DuplexTransportConnection;

briar-core/src/net/sf/briar/messaging/duplex/DuplexConnectionFactoryImpl.java

@@ -6,6 +6,7 @@ import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
 import net.sf.briar.api.ContactId;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.crypto.CryptoExecutor;
 import net.sf.briar.api.crypto.KeyManager;
 import net.sf.briar.api.db.DatabaseComponent;
@@ -13,7 +14,6 @@ import net.sf.briar.api.db.DatabaseExecutor;
 import net.sf.briar.api.messaging.MessageVerifier;
 import net.sf.briar.api.messaging.PacketReaderFactory;
 import net.sf.briar.api.messaging.PacketWriterFactory;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.messaging.duplex.DuplexConnectionFactory;
 import net.sf.briar.api.plugins.duplex.DuplexTransportConnection;
 import net.sf.briar.api.transport.ConnectionContext;

briar-core/src/net/sf/briar/messaging/simplex/IncomingSimplexConnection.java

@@ -10,6 +10,7 @@ import java.util.logging.Logger;
 
 import net.sf.briar.api.ContactId;
 import net.sf.briar.api.FormatException;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.crypto.CryptoExecutor;
 import net.sf.briar.api.db.DatabaseComponent;
 import net.sf.briar.api.db.DatabaseExecutor;
@@ -24,7 +25,6 @@ import net.sf.briar.api.messaging.RetentionUpdate;
 import net.sf.briar.api.messaging.SubscriptionAck;
 import net.sf.briar.api.messaging.SubscriptionUpdate;
 import net.sf.briar.api.messaging.TransportAck;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.messaging.TransportUpdate;
 import net.sf.briar.api.messaging.UnverifiedMessage;
 import net.sf.briar.api.plugins.simplex.SimplexTransportReader;

briar-core/src/net/sf/briar/messaging/simplex/OutgoingSimplexConnection.java

@@ -10,6 +10,7 @@ import java.util.Collection;
 import java.util.logging.Logger;
 
 import net.sf.briar.api.ContactId;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.db.DatabaseComponent;
 import net.sf.briar.api.db.DbException;
 import net.sf.briar.api.messaging.Ack;
@@ -20,7 +21,6 @@ import net.sf.briar.api.messaging.RetentionUpdate;
 import net.sf.briar.api.messaging.SubscriptionAck;
 import net.sf.briar.api.messaging.SubscriptionUpdate;
 import net.sf.briar.api.messaging.TransportAck;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.messaging.TransportUpdate;
 import net.sf.briar.api.plugins.simplex.SimplexTransportWriter;
 import net.sf.briar.api.transport.ConnectionContext;

briar-core/src/net/sf/briar/messaging/simplex/SimplexConnectionFactoryImpl.java

@@ -6,6 +6,7 @@ import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
 import net.sf.briar.api.ContactId;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.crypto.CryptoExecutor;
 import net.sf.briar.api.crypto.KeyManager;
 import net.sf.briar.api.db.DatabaseComponent;
@@ -13,7 +14,6 @@ import net.sf.briar.api.db.DatabaseExecutor;
 import net.sf.briar.api.messaging.MessageVerifier;
 import net.sf.briar.api.messaging.PacketReaderFactory;
 import net.sf.briar.api.messaging.PacketWriterFactory;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.messaging.simplex.SimplexConnectionFactory;
 import net.sf.briar.api.plugins.simplex.SimplexTransportReader;
 import net.sf.briar.api.plugins.simplex.SimplexTransportWriter;

briar-core/src/net/sf/briar/plugins/PluginManagerImpl.java

@@ -16,11 +16,11 @@ import java.util.logging.Logger;
 
 import net.sf.briar.api.ContactId;
 import net.sf.briar.api.TransportConfig;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.TransportProperties;
 import net.sf.briar.api.android.AndroidExecutor;
 import net.sf.briar.api.db.DatabaseComponent;
 import net.sf.briar.api.db.DbException;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.plugins.Plugin;
 import net.sf.briar.api.plugins.PluginCallback;
 import net.sf.briar.api.plugins.PluginExecutor;
@@ -88,12 +88,6 @@ class PluginManagerImpl implements PluginManager {
 					LOG.warning("Duplicate transport ID: " + id);
 				continue;
 			}
-			try {
-				db.addTransport(id);
-			} catch(DbException e) {
-				if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-				continue;
-			}
 			SimplexCallback callback = new SimplexCallback(id);
 			SimplexPlugin plugin = factory.createPlugin(callback);
 			if(plugin == null) {
@@ -103,6 +97,12 @@ class PluginManagerImpl implements PluginManager {
 				}
 				continue;
 			}
+			try {
+				db.addTransport(id, plugin.getMaxLatency());
+			} catch(DbException e) {
+				if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+				continue;
+			}
 			try {
 				if(plugin.start()) {
 					simplexPlugins.add(plugin);
@@ -124,12 +124,6 @@ class PluginManagerImpl implements PluginManager {
 					LOG.warning("Duplicate transport ID: " + id);
 				continue;
 			}
-			try {
-				db.addTransport(id);
-			} catch(DbException e) {
-				if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-				continue;
-			}
 			DuplexCallback callback = new DuplexCallback(id);
 			DuplexPlugin plugin = factory.createPlugin(callback);
 			if(plugin == null) {
@@ -139,6 +133,12 @@ class PluginManagerImpl implements PluginManager {
 				}
 				continue;
 			}
+			try {
+				db.addTransport(id, plugin.getMaxLatency());
+			} catch(DbException e) {
+				if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+				continue;
+			}
 			try {
 				if(plugin.start()) {
 					duplexPlugins.add(plugin);
@@ -197,10 +197,10 @@ class PluginManagerImpl implements PluginManager {
 	}
 
 	public synchronized Collection<DuplexPlugin> getInvitationPlugins() {
-		Collection<DuplexPlugin> supported = new ArrayList<DuplexPlugin>();
+		List<DuplexPlugin> supported = new ArrayList<DuplexPlugin>();
 		for(DuplexPlugin d : duplexPlugins)
 			if(d.supportsInvitations()) supported.add(d);
-		return supported;
+		return Collections.unmodifiableList(supported);
 	}
 
 	private abstract class PluginCallbackImpl implements PluginCallback {

briar-core/src/net/sf/briar/plugins/bluetooth/BluetoothPlugin.java

@@ -26,10 +26,10 @@ import javax.microedition.io.StreamConnection;
 import javax.microedition.io.StreamConnectionNotifier;
 
 import net.sf.briar.api.ContactId;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.TransportProperties;
 import net.sf.briar.api.clock.Clock;
 import net.sf.briar.api.crypto.PseudoRandom;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.plugins.PluginExecutor;
 import net.sf.briar.api.plugins.duplex.DuplexPlugin;
 import net.sf.briar.api.plugins.duplex.DuplexPluginCallback;

briar-core/src/net/sf/briar/plugins/bluetooth/BluetoothPluginFactory.java

@@ -3,9 +3,9 @@ package net.sf.briar.plugins.bluetooth;
 import java.security.SecureRandom;
 import java.util.concurrent.Executor;
 
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.clock.Clock;
 import net.sf.briar.api.clock.SystemClock;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.plugins.PluginExecutor;
 import net.sf.briar.api.plugins.duplex.DuplexPlugin;
 import net.sf.briar.api.plugins.duplex.DuplexPluginCallback;

briar-core/src/net/sf/briar/plugins/droidtooth/DroidtoothPlugin.java

@@ -24,10 +24,10 @@ import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
 import net.sf.briar.api.ContactId;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.TransportProperties;
 import net.sf.briar.api.android.AndroidExecutor;
 import net.sf.briar.api.crypto.PseudoRandom;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.plugins.PluginExecutor;
 import net.sf.briar.api.plugins.duplex.DuplexPlugin;
 import net.sf.briar.api.plugins.duplex.DuplexPluginCallback;

briar-core/src/net/sf/briar/plugins/droidtooth/DroidtoothPluginFactory.java

@@ -3,8 +3,8 @@ package net.sf.briar.plugins.droidtooth;
 import java.security.SecureRandom;
 import java.util.concurrent.Executor;
 
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.android.AndroidExecutor;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.plugins.PluginExecutor;
 import net.sf.briar.api.plugins.duplex.DuplexPlugin;
 import net.sf.briar.api.plugins.duplex.DuplexPluginCallback;

briar-core/src/net/sf/briar/plugins/file/RemovableDrivePlugin.java

@@ -12,7 +12,7 @@ import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
 import net.sf.briar.api.ContactId;
-import net.sf.briar.api.messaging.TransportId;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.plugins.PluginExecutor;
 import net.sf.briar.api.plugins.simplex.SimplexPluginCallback;
 import net.sf.briar.util.StringUtils;

briar-core/src/net/sf/briar/plugins/file/RemovableDrivePluginFactory.java

@@ -2,7 +2,7 @@ package net.sf.briar.plugins.file;
 
 import java.util.concurrent.Executor;
 
-import net.sf.briar.api.messaging.TransportId;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.plugins.PluginExecutor;
 import net.sf.briar.api.plugins.simplex.SimplexPlugin;
 import net.sf.briar.api.plugins.simplex.SimplexPluginCallback;

briar-core/src/net/sf/briar/plugins/modem/ModemPlugin.java

@@ -17,9 +17,9 @@ import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
 import net.sf.briar.api.ContactId;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.TransportProperties;
 import net.sf.briar.api.crypto.PseudoRandom;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.plugins.PluginExecutor;
 import net.sf.briar.api.plugins.duplex.DuplexPlugin;
 import net.sf.briar.api.plugins.duplex.DuplexPluginCallback;

briar-core/src/net/sf/briar/plugins/modem/ModemPluginFactory.java

@@ -2,7 +2,7 @@ package net.sf.briar.plugins.modem;
 
 import java.util.concurrent.Executor;
 
-import net.sf.briar.api.messaging.TransportId;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.plugins.PluginExecutor;
 import net.sf.briar.api.plugins.duplex.DuplexPlugin;
 import net.sf.briar.api.plugins.duplex.DuplexPluginCallback;

briar-core/src/net/sf/briar/plugins/tcp/LanTcpPlugin.java

@@ -21,10 +21,10 @@ import java.util.List;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.TransportProperties;
 import net.sf.briar.api.clock.Clock;
 import net.sf.briar.api.crypto.PseudoRandom;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.plugins.PluginExecutor;
 import net.sf.briar.api.plugins.duplex.DuplexPluginCallback;
 import net.sf.briar.api.plugins.duplex.DuplexTransportConnection;

briar-core/src/net/sf/briar/plugins/tcp/LanTcpPluginFactory.java

@@ -2,9 +2,9 @@ package net.sf.briar.plugins.tcp;
 
 import java.util.concurrent.Executor;
 
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.clock.Clock;
 import net.sf.briar.api.clock.SystemClock;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.plugins.PluginExecutor;
 import net.sf.briar.api.plugins.duplex.DuplexPlugin;
 import net.sf.briar.api.plugins.duplex.DuplexPluginCallback;

briar-core/src/net/sf/briar/plugins/tcp/WanTcpPlugin.java

@@ -14,9 +14,9 @@ import java.util.List;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.TransportProperties;
 import net.sf.briar.api.crypto.PseudoRandom;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.plugins.PluginExecutor;
 import net.sf.briar.api.plugins.duplex.DuplexPluginCallback;
 import net.sf.briar.api.plugins.duplex.DuplexTransportConnection;

briar-core/src/net/sf/briar/plugins/tcp/WanTcpPluginFactory.java

@@ -2,8 +2,8 @@ package net.sf.briar.plugins.tcp;
 
 import java.util.concurrent.Executor;
 
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.lifecycle.ShutdownManager;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.plugins.PluginExecutor;
 import net.sf.briar.api.plugins.duplex.DuplexPlugin;
 import net.sf.briar.api.plugins.duplex.DuplexPluginCallback;

briar-core/src/net/sf/briar/serial/SerialComponentImpl.java

@@ -1,6 +1,6 @@
 package net.sf.briar.serial;
 
-import net.sf.briar.api.messaging.UniqueId;
+import net.sf.briar.api.UniqueId;
 import net.sf.briar.api.serial.SerialComponent;
 
 class SerialComponentImpl implements SerialComponent {

briar-core/src/net/sf/briar/transport/ConnectionDispatcherImpl.java

@@ -10,8 +10,8 @@ import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
 import net.sf.briar.api.ContactId;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.db.DbException;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.messaging.duplex.DuplexConnectionFactory;
 import net.sf.briar.api.messaging.simplex.SimplexConnectionFactory;
 import net.sf.briar.api.plugins.duplex.DuplexTransportConnection;

briar-core/src/net/sf/briar/transport/ConnectionReaderFactoryImpl.java

@@ -33,4 +33,12 @@ class ConnectionReaderFactoryImpl implements ConnectionReaderFactory {
 				crypto.getFrameCipher(), frameKey, MAX_FRAME_LENGTH);
 		return new ConnectionReaderImpl(encryption, MAX_FRAME_LENGTH);
 	}
+
+	public ConnectionReader createInvitationConnectionReader(InputStream in,
+			byte[] secret, boolean alice) {
+		ErasableKey frameKey = crypto.deriveFrameKey(secret, 0, true, alice);
+		FrameReader encryption = new IncomingEncryptionLayer(in,
+				crypto.getFrameCipher(), frameKey, MAX_FRAME_LENGTH);
+		return new ConnectionReaderImpl(encryption, MAX_FRAME_LENGTH);
+	}
 }

briar-core/src/net/sf/briar/transport/ConnectionRecogniserImpl.java

@@ -4,10 +4,10 @@ import java.util.HashMap;
 import java.util.Map;
 
 import net.sf.briar.api.ContactId;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.crypto.CryptoComponent;
 import net.sf.briar.api.db.DatabaseComponent;
 import net.sf.briar.api.db.DbException;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.transport.ConnectionContext;
 import net.sf.briar.api.transport.ConnectionRecogniser;
 import net.sf.briar.api.transport.TemporarySecret;

briar-core/src/net/sf/briar/transport/ConnectionRegistryImpl.java

@@ -9,7 +9,7 @@ import java.util.Map;
 import java.util.concurrent.CopyOnWriteArrayList;
 
 import net.sf.briar.api.ContactId;
-import net.sf.briar.api.messaging.TransportId;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.transport.ConnectionListener;
 import net.sf.briar.api.transport.ConnectionRegistry;
 

briar-core/src/net/sf/briar/transport/ConnectionWriterFactoryImpl.java

@@ -13,7 +13,6 @@ import net.sf.briar.api.transport.ConnectionContext;
 import net.sf.briar.api.transport.ConnectionWriter;
 import net.sf.briar.api.transport.ConnectionWriterFactory;
 
-
 import com.google.inject.Inject;
 
 class ConnectionWriterFactoryImpl implements ConnectionWriterFactory {
@@ -48,4 +47,13 @@ class ConnectionWriterFactoryImpl implements ConnectionWriterFactory {
 		}
 		return new ConnectionWriterImpl(encryption, MAX_FRAME_LENGTH);
 	}
+
+	public ConnectionWriter createInvitationConnectionWriter(OutputStream out,
+			byte[] secret, boolean alice) {
+		ErasableKey frameKey = crypto.deriveFrameKey(secret, 0, true, alice);
+		FrameWriter encryption = new OutgoingEncryptionLayer(out,
+				Long.MAX_VALUE, crypto.getFrameCipher(), frameKey,
+				MAX_FRAME_LENGTH);
+		return new ConnectionWriterImpl(encryption, MAX_FRAME_LENGTH);
+	}
 }

briar-core/src/net/sf/briar/transport/ConnectionWriterImpl.java

@@ -6,7 +6,6 @@ import static net.sf.briar.api.transport.TransportConstants.MAC_LENGTH;
 import java.io.IOException;
 import java.io.OutputStream;
 
-
 import net.sf.briar.api.transport.ConnectionWriter;
 
 /**

briar-core/src/net/sf/briar/transport/KeyManagerImpl.java

@@ -1,6 +1,7 @@
 package net.sf.briar.transport;
 
 import static java.util.logging.Level.WARNING;
+import static net.sf.briar.api.transport.TransportConstants.MAX_CLOCK_DIFFERENCE;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -12,6 +13,7 @@ import java.util.TimerTask;
 import java.util.logging.Logger;
 
 import net.sf.briar.api.ContactId;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.clock.Clock;
 import net.sf.briar.api.clock.Timer;
 import net.sf.briar.api.crypto.CryptoComponent;
@@ -21,8 +23,8 @@ import net.sf.briar.api.db.DbException;
 import net.sf.briar.api.db.event.ContactRemovedEvent;
 import net.sf.briar.api.db.event.DatabaseEvent;
 import net.sf.briar.api.db.event.DatabaseListener;
+import net.sf.briar.api.db.event.TransportAddedEvent;
 import net.sf.briar.api.db.event.TransportRemovedEvent;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.transport.ConnectionContext;
 import net.sf.briar.api.transport.ConnectionRecogniser;
 import net.sf.briar.api.transport.Endpoint;
@@ -31,6 +33,7 @@ import net.sf.briar.util.ByteUtils;
 
 import com.google.inject.Inject;
 
+// FIXME: Don't make alien calls with a lock held
 class KeyManagerImpl extends TimerTask implements KeyManager, DatabaseListener {
 
 	private static final int MS_BETWEEN_CHECKS = 60 * 1000;
@@ -40,34 +43,38 @@ class KeyManagerImpl extends TimerTask implements KeyManager, DatabaseListener {
 
 	private final CryptoComponent crypto;
 	private final DatabaseComponent db;
-	private final ConnectionRecogniser recogniser;
+	private final ConnectionRecogniser connectionRecogniser;
 	private final Clock clock;
 	private final Timer timer;
-	// Locking: this
+
+	// All of the following are locking: this
+	private final Map<TransportId, Long> maxLatencies;
 	private final Map<EndpointKey, TemporarySecret> outgoing;
-	// Locking: this
 	private final Map<EndpointKey, TemporarySecret> incomingOld;
-	// Locking: this
 	private final Map<EndpointKey, TemporarySecret> incomingNew;
 
 	@Inject
 	KeyManagerImpl(CryptoComponent crypto, DatabaseComponent db,
-			ConnectionRecogniser recogniser, Clock clock, Timer timer) {
+			ConnectionRecogniser connectionRecogniser, Clock clock,
+			Timer timer) {
 		this.crypto = crypto;
 		this.db = db;
-		this.recogniser = recogniser;
+		this.connectionRecogniser = connectionRecogniser;
 		this.clock = clock;
 		this.timer = timer;
+		maxLatencies = new HashMap<TransportId, Long>();
 		outgoing = new HashMap<EndpointKey, TemporarySecret>();
 		incomingOld = new HashMap<EndpointKey, TemporarySecret>();
 		incomingNew = new HashMap<EndpointKey, TemporarySecret>();
 	}
 
 	public synchronized boolean start() {
-		// Load the temporary secrets and the storage key from the database
+		db.addListener(this);
+		// Load the temporary secrets and transport latencies from the database
 		Collection<TemporarySecret> secrets;
 		try {
 			secrets = db.getSecrets();
+			maxLatencies.putAll(db.getTransportLatencies());
 		} catch(DbException e) {
 			if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			return false;
@@ -87,129 +94,111 @@ class KeyManagerImpl extends TimerTask implements KeyManager, DatabaseListener {
 			}
 		}
 		// Pass the current incoming secrets to the recogniser
-		for(TemporarySecret s : incomingOld.values()) recogniser.addSecret(s);
-		for(TemporarySecret s : incomingNew.values()) recogniser.addSecret(s);
+		for(TemporarySecret s : incomingOld.values())
+			connectionRecogniser.addSecret(s);
+		for(TemporarySecret s : incomingNew.values())
+			connectionRecogniser.addSecret(s);
 		// Schedule periodic key rotation
 		timer.scheduleAtFixedRate(this, MS_BETWEEN_CHECKS, MS_BETWEEN_CHECKS);
 		return true;
 	}
 
 	// Assigns secrets to the appropriate maps and returns any dead secrets
+	// Locking: this
 	private Collection<TemporarySecret> assignSecretsToMaps(long now,
 			Collection<TemporarySecret> secrets) {
 		Collection<TemporarySecret> dead = new ArrayList<TemporarySecret>();
 		for(TemporarySecret s : secrets) {
+			// Discard the secret if the transport has been removed
+			if(!maxLatencies.containsKey(s.getTransportId())) {
+				ByteUtils.erase(s.getSecret());
+				continue;
+			}
 			EndpointKey k = new EndpointKey(s);
 			long rotationPeriod = getRotationPeriod(s);
 			long creationTime = getCreationTime(s);
-			long activationTime = creationTime + s.getClockDifference();
+			long activationTime = creationTime + MAX_CLOCK_DIFFERENCE;
 			long successorCreationTime = creationTime + rotationPeriod;
 			long deactivationTime = activationTime + rotationPeriod;
 			long destructionTime = successorCreationTime + rotationPeriod;
-			TemporarySecret dupe; // There should not be any duplicate keys
 			if(now >= destructionTime) {
 				dead.add(s);
 			} else if(now >= deactivationTime) {
-				dupe = incomingOld.put(k, s);
-				if(dupe != null) throw new IllegalStateException();
+				incomingOld.put(k, s);
 			} else if(now >= successorCreationTime) {
-				dupe = incomingOld.put(k, s);
-				if(dupe != null) throw new IllegalStateException();
-				dupe = outgoing.put(k, s);
-				if(dupe != null) throw new IllegalStateException();
+				incomingOld.put(k, s);
+				outgoing.put(k, s);
 			} else if(now >= activationTime) {
-				dupe = incomingNew.put(k, s);
-				if(dupe != null) throw new IllegalStateException();
-				dupe = outgoing.put(k, s);
-				if(dupe != null) throw new IllegalStateException();
+				incomingNew.put(k, s);
+				outgoing.put(k, s);
 			} else if(now >= creationTime) {
-				dupe = incomingNew.put(k, s);
-				if(dupe != null) throw new IllegalStateException();
+				incomingNew.put(k, s);
 			} else {
-				// FIXME: What should we do if the clock moves backwards?
-				throw new IllegalStateException();
+				throw new Error("Clock has moved backwards");
 			}
 		}
 		return dead;
 	}
 
 	// Replaces and erases the given secrets and returns any secrets created
+	// Locking: this
 	private Collection<TemporarySecret> replaceDeadSecrets(long now,
 			Collection<TemporarySecret> dead) {
 		Collection<TemporarySecret> created = new ArrayList<TemporarySecret>();
 		for(TemporarySecret s : dead) {
-			EndpointKey k = new EndpointKey(s);
-			if(incomingNew.containsKey(k)) throw new IllegalStateException();
-			byte[] secret = s.getSecret();
-			long period = s.getPeriod();
-			TemporarySecret dupe; // There should not be any duplicate keys
-			if(incomingOld.containsKey(k)) {
-				// The dead secret's successor is still alive
-				byte[] secret1 = crypto.deriveNextSecret(secret, period + 1);
-				TemporarySecret s1 = new TemporarySecret(s, period + 1,
-						secret1);
-				created.add(s1);
-				dupe = incomingNew.put(k, s1);
-				if(dupe != null) throw new IllegalStateException();
-				long creationTime = getCreationTime(s1);
-				long activationTime = creationTime + s1.getClockDifference();
-				if(now >= activationTime) {
-					dupe = outgoing.put(k, s1);
-					if(dupe != null) throw new IllegalStateException();
-				}
-			} else  {
-				// The dead secret has no living successor
-				long rotationPeriod = getRotationPeriod(s);
-				long elapsed = now - s.getEpoch();
-				long currentPeriod = elapsed / rotationPeriod;
-				if(currentPeriod <= period) throw new IllegalStateException();
-				// Derive the two current incoming secrets
-				byte[] secret1, secret2;
-				secret1 = secret;
-				for(long p = period; p < currentPeriod; p++) {
-					byte[] temp = crypto.deriveNextSecret(secret1, p);
-					ByteUtils.erase(secret1);
-					secret1 = temp;
-				}
-				secret2 = crypto.deriveNextSecret(secret1, currentPeriod);
-				// One of the incoming secrets is the current outgoing secret
-				TemporarySecret s1, s2;
-				s1 = new TemporarySecret(s, currentPeriod - 1, secret1);
-				created.add(s1);
-				dupe = incomingOld.put(k, s1);
-				if(dupe != null) throw new IllegalStateException();
-				s2 = new TemporarySecret(s, currentPeriod, secret2);
-				created.add(s2);
-				dupe = incomingNew.put(k, s2);
-				if(dupe != null) throw new IllegalStateException();
-				if(elapsed % rotationPeriod < s.getClockDifference()) {
-					// The outgoing secret is the newer incoming secret
-					dupe = outgoing.put(k, s2);
-					if(dupe != null) throw new IllegalStateException();
-				} else {
-					// The outgoing secret is the older incoming secret
-					dupe = outgoing.put(k, s1);
-					if(dupe != null) throw new IllegalStateException();
-				}
+			// Work out which rotation period we're in
+			long rotationPeriod = getRotationPeriod(s);
+			long elapsed = now - s.getEpoch();
+			long period = (elapsed / rotationPeriod) + 1;
+			if(period <= s.getPeriod()) throw new IllegalStateException();
+			// Derive the two current incoming secrets
+			byte[] secret1 = s.getSecret();
+			for(long p = s.getPeriod(); p < period; p++) {
+				byte[] temp = crypto.deriveNextSecret(secret1, p);
+				ByteUtils.erase(secret1);
+				secret1 = temp;
+			}
+			byte[] secret2 = crypto.deriveNextSecret(secret1, period);
+			// Add the incoming secrets to their respective maps - the older
+			// may already exist if the dead secret has a living successor
+			EndpointKey k = new EndpointKey(s);
+			TemporarySecret s1 = new TemporarySecret(s, period - 1, secret1);
+			created.add(s1);
+			TemporarySecret exists = incomingOld.put(k, s1);
+			if(exists != null) ByteUtils.erase(exists.getSecret());
+			TemporarySecret s2 = new TemporarySecret(s, period, secret2);
+			created.add(s2);
+			incomingNew.put(k, s2);
+			// One of the incoming secrets is the current outgoing secret
+			if(elapsed % rotationPeriod < MAX_CLOCK_DIFFERENCE) {
+				// The outgoing secret is the older incoming secret
+				outgoing.put(k, s1);
+			} else {
+				// The outgoing secret is the newer incoming secret
+				outgoing.put(k, s2);
 			}
-			// Erase the dead secret
-			ByteUtils.erase(secret);
 		}
 		return created;
 	}
 
+	// Locking: this
 	private long getRotationPeriod(Endpoint ep) {
-		return 2 * ep.getClockDifference() + ep.getLatency();
+		Long maxLatency = maxLatencies.get(ep.getTransportId());
+		if(maxLatency == null) throw new IllegalStateException();
+		return 2 * MAX_CLOCK_DIFFERENCE + maxLatency;
 	}
 
+	// Locking: this
 	private long getCreationTime(TemporarySecret s) {
 		long rotationPeriod = getRotationPeriod(s);
 		return s.getEpoch() + rotationPeriod * s.getPeriod();
 	}
 
 	public synchronized void stop() {
+		db.removeListener(this);
 		timer.cancel();
-		recogniser.removeSecrets();
+		connectionRecogniser.removeSecrets();
+		maxLatencies.clear();
 		removeAndEraseSecrets(outgoing);
 		removeAndEraseSecrets(incomingOld);
 		removeAndEraseSecrets(incomingNew);
@@ -236,50 +225,49 @@ class KeyManagerImpl extends TimerTask implements KeyManager, DatabaseListener {
 		return new ConnectionContext(c, t, secret, connection, s.getAlice());
 	}
 
-	public synchronized void endpointAdded(Endpoint ep, byte[] initialSecret) {		
+	public synchronized void endpointAdded(Endpoint ep, byte[] initialSecret) {
+		if(!maxLatencies.containsKey(ep.getTransportId())) {
+			if(LOG.isLoggable(WARNING)) LOG.warning("No such transport");
+			return;
+		}
+		// Work out which rotation period we're in
 		long now = clock.currentTimeMillis();
 		long rotationPeriod = getRotationPeriod(ep);
 		long elapsed = now - ep.getEpoch();
-		long currentPeriod = elapsed / rotationPeriod;
-		if(currentPeriod < 1) throw new IllegalArgumentException();
+		long period = (elapsed / rotationPeriod) + 1;
+		if(period < 1) throw new IllegalStateException();
 		// Derive the two current incoming secrets
-		byte[] secret1, secret2;
-		secret1 = initialSecret;
-		for(long p = 0; p < currentPeriod; p++) {
+		byte[] secret1 = initialSecret;
+		for(long p = 0; p < period; p++) {
 			byte[] temp = crypto.deriveNextSecret(secret1, p);
 			ByteUtils.erase(secret1);
 			secret1 = temp;
 		}
-		secret2 = crypto.deriveNextSecret(secret1, currentPeriod);
-		// One of the incoming secrets is the current outgoing secret
+		byte[] secret2 = crypto.deriveNextSecret(secret1, period);
+		// Add the incoming secrets to their respective maps
 		EndpointKey k = new EndpointKey(ep);
-		TemporarySecret s1, s2, dupe;
-		s1 = new TemporarySecret(ep, currentPeriod - 1, secret1);
-		dupe = incomingOld.put(k, s1);
-		if(dupe != null) throw new IllegalStateException();
-		s2 = new TemporarySecret(ep, currentPeriod, secret2);
-		dupe = incomingNew.put(k, s2);
-		if(dupe != null) throw new IllegalStateException();
-		if(elapsed % rotationPeriod < ep.getClockDifference()) {
-			// The outgoing secret is the newer incoming secret
-			dupe = outgoing.put(k, s2);
-			if(dupe != null) throw new IllegalStateException();
-		} else {
+		TemporarySecret s1 = new TemporarySecret(ep, period - 1, secret1);
+		incomingOld.put(k, s1);
+		TemporarySecret s2 = new TemporarySecret(ep, period, secret2);
+		incomingNew.put(k, s2);
+		// One of the incoming secrets is the current outgoing secret
+		if(elapsed % rotationPeriod < MAX_CLOCK_DIFFERENCE) {
 			// The outgoing secret is the older incoming secret
-			dupe = outgoing.put(k, s1);
-			if(dupe != null) throw new IllegalStateException();
+			outgoing.put(k, s1);
+		} else {
+			// The outgoing secret is the newer incoming secret
+			outgoing.put(k, s2);
 		}
 		// Store the new secrets
 		try {
 			db.addSecrets(Arrays.asList(s1, s2));
 		} catch(DbException e) {
 			if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+			return;
 		}
 		// Pass the new secrets to the recogniser
-		recogniser.addSecret(s1);
-		recogniser.addSecret(s2);
-		// Erase the initial secret
-		ByteUtils.erase(initialSecret);
+		connectionRecogniser.addSecret(s1);
+		connectionRecogniser.addSecret(s2);
 	}
 
 	@Override
@@ -299,7 +287,7 @@ class KeyManagerImpl extends TimerTask implements KeyManager, DatabaseListener {
 			ContactId c = s.getContactId();
 			TransportId t = s.getTransportId();
 			long period = s.getPeriod();
-			recogniser.removeSecret(c, t, period);
+			connectionRecogniser.removeSecret(c, t, period);
 		}
 		// Replace any dead secrets
 		Collection<TemporarySecret> created = replaceDeadSecrets(now, dead);
@@ -311,23 +299,29 @@ class KeyManagerImpl extends TimerTask implements KeyManager, DatabaseListener {
 				if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			}
 			// Pass any secrets that have been created to the recogniser
-			for(TemporarySecret s : created) recogniser.addSecret(s);
+			for(TemporarySecret s : created) connectionRecogniser.addSecret(s);
 		}
 	}
 
 	public void eventOccurred(DatabaseEvent e) {
 		if(e instanceof ContactRemovedEvent) {
 			ContactId c = ((ContactRemovedEvent) e).getContactId();
-			recogniser.removeSecrets(c);
+			connectionRecogniser.removeSecrets(c);
 			synchronized(this) {
 				removeAndEraseSecrets(c, outgoing);
 				removeAndEraseSecrets(c, incomingOld);
 				removeAndEraseSecrets(c, incomingNew);
 			}
+		} else if(e instanceof TransportAddedEvent) {
+			TransportAddedEvent t = (TransportAddedEvent) e;
+			synchronized(this) {
+				maxLatencies.put(t.getTransportId(), t.getMaxLatency());
+			}
 		} else if(e instanceof TransportRemovedEvent) {
 			TransportId t = ((TransportRemovedEvent) e).getTransportId();
-			recogniser.removeSecrets(t);
+			connectionRecogniser.removeSecrets(t);
 			synchronized(this) {
+				maxLatencies.remove(t);
 				removeAndEraseSecrets(t, outgoing);
 				removeAndEraseSecrets(t, incomingOld);
 				removeAndEraseSecrets(t, incomingNew);

briar-core/src/net/sf/briar/transport/OutgoingEncryptionLayer.java

@@ -11,7 +11,6 @@ import java.io.IOException;
 import java.io.OutputStream;
 import java.security.GeneralSecurityException;
 
-
 import net.sf.briar.api.crypto.AuthenticatedCipher;
 import net.sf.briar.api.crypto.ErasableKey;
 

briar-core/src/net/sf/briar/transport/TransportConnectionRecogniser.java

@@ -11,11 +11,11 @@ import javax.crypto.Cipher;
 
 import net.sf.briar.api.Bytes;
 import net.sf.briar.api.ContactId;
+import net.sf.briar.api.TransportId;
 import net.sf.briar.api.crypto.CryptoComponent;
 import net.sf.briar.api.crypto.ErasableKey;
 import net.sf.briar.api.db.DatabaseComponent;
 import net.sf.briar.api.db.DbException;
-import net.sf.briar.api.messaging.TransportId;
 import net.sf.briar.api.transport.ConnectionContext;
 import net.sf.briar.api.transport.TemporarySecret;
 import net.sf.briar.util.ByteUtils;