private PreKeyBundle createBobPreKeyBundle(AxolotlStore bobStore) throws InvalidKeyException {
ECKeyPair bobUnsignedPreKey = Curve.generateKeyPair();
int bobUnsignedPreKeyId = new Random().nextInt(Medium.MAX_VALUE);
byte[] bobSignature =
Curve.calculateSignature(
bobStore.getIdentityKeyPair().getPrivateKey(),
bobSignedPreKey.getPublicKey().serialize());
PreKeyBundle bobPreKeyBundle =
new PreKeyBundle(
1,
1,
bobUnsignedPreKeyId,
bobUnsignedPreKey.getPublicKey(),
bobSignedPreKeyId,
bobSignedPreKey.getPublicKey(),
bobSignature,
bobStore.getIdentityKeyPair().getPublicKey());
bobStore.storeSignedPreKey(
bobSignedPreKeyId,
new SignedPreKeyRecord(
bobSignedPreKeyId, System.currentTimeMillis(), bobSignedPreKey, bobSignature));
bobStore.storePreKey(
bobUnsignedPreKeyId, new PreKeyRecord(bobUnsignedPreKeyId, bobUnsignedPreKey));
return bobPreKeyBundle;
}
public static AsymmetricMasterSecret generateAsymmetricMasterSecret(
Context context, MasterSecret masterSecret) {
MasterCipher masterCipher = new MasterCipher(masterSecret);
ECKeyPair keyPair = Curve.generateKeyPair();
save(context, ASYMMETRIC_LOCAL_PUBLIC_DJB, keyPair.getPublicKey().serialize());
save(context, ASYMMETRIC_LOCAL_PRIVATE_DJB, masterCipher.encryptKey(keyPair.getPrivateKey()));
return new AsymmetricMasterSecret(keyPair.getPublicKey(), keyPair.getPrivateKey());
}
private void initializeSessionsV3(SessionState aliceSessionState, SessionState bobSessionState)
throws InvalidKeyException {
ECKeyPair aliceIdentityKeyPair = Curve.generateKeyPair();
IdentityKeyPair aliceIdentityKey =
new IdentityKeyPair(
new IdentityKey(aliceIdentityKeyPair.getPublicKey()),
aliceIdentityKeyPair.getPrivateKey());
ECKeyPair aliceBaseKey = Curve.generateKeyPair();
ECKeyPair aliceEphemeralKey = Curve.generateKeyPair();
ECKeyPair alicePreKey = aliceBaseKey;
ECKeyPair bobIdentityKeyPair = Curve.generateKeyPair();
IdentityKeyPair bobIdentityKey =
new IdentityKeyPair(
new IdentityKey(bobIdentityKeyPair.getPublicKey()), bobIdentityKeyPair.getPrivateKey());
ECKeyPair bobBaseKey = Curve.generateKeyPair();
ECKeyPair bobEphemeralKey = bobBaseKey;
ECKeyPair bobPreKey = Curve.generateKeyPair();
AliceAxolotlParameters aliceParameters =
AliceAxolotlParameters.newBuilder()
.setOurBaseKey(aliceBaseKey)
.setOurIdentityKey(aliceIdentityKey)
.setTheirOneTimePreKey(Optional.<ECPublicKey>absent())
.setTheirRatchetKey(bobEphemeralKey.getPublicKey())
.setTheirSignedPreKey(bobBaseKey.getPublicKey())
.setTheirIdentityKey(bobIdentityKey.getPublicKey())
.create();
BobAxolotlParameters bobParameters =
BobAxolotlParameters.newBuilder()
.setOurRatchetKey(bobEphemeralKey)
.setOurSignedPreKey(bobBaseKey)
.setOurOneTimePreKey(Optional.<ECKeyPair>absent())
.setOurIdentityKey(bobIdentityKey)
.setTheirIdentityKey(aliceIdentityKey.getPublicKey())
.setTheirBaseKey(aliceBaseKey.getPublicKey())
.create();
RatchetingSession.initializeSession(aliceSessionState, 3, aliceParameters);
RatchetingSession.initializeSession(bobSessionState, 3, bobParameters);
}
public byte[] encryptBytes(byte[] body) {
try {
ECPublicKey theirPublic = asymmetricMasterSecret.getDjbPublicKey();
ECKeyPair ourKeyPair = Curve.generateKeyPair();
byte[] secret = Curve.calculateAgreement(theirPublic, ourKeyPair.getPrivateKey());
MasterCipher masterCipher = getMasterCipherForSecret(secret);
byte[] encryptedBodyBytes = masterCipher.encryptBytes(body);
PublicKey ourPublicKey = new PublicKey(31337, ourKeyPair.getPublicKey());
byte[] publicKeyBytes = ourPublicKey.serialize();
return Util.combine(publicKeyBytes, encryptedBodyBytes);
} catch (InvalidKeyException e) {
throw new AssertionError(e);
}
}
public static SignedPreKeyRecord generateSignedPreKey(
Context context, MasterSecret masterSecret, IdentityKeyPair identityKeyPair) {
try {
SignedPreKeyStore signedPreKeyStore = new TextSecurePreKeyStore(context, masterSecret);
int signedPreKeyId = getNextSignedPreKeyId(context);
ECKeyPair keyPair = Curve.generateKeyPair();
byte[] signature =
Curve.calculateSignature(
identityKeyPair.getPrivateKey(), keyPair.getPublicKey().serialize());
SignedPreKeyRecord record =
new SignedPreKeyRecord(signedPreKeyId, System.currentTimeMillis(), keyPair, signature);
signedPreKeyStore.storeSignedPreKey(signedPreKeyId, record);
setNextSignedPreKeyId(context, (signedPreKeyId + 1) % Medium.MAX_VALUE);
return record;
} catch (InvalidKeyException e) {
throw new AssertionError(e);
}
}