/// <summary>
        /// Build a new session from a {@link org.whispersystems.libsignal.state.PreKeyBundle} retrieved from
        /// a server.
        /// </summary>
        /// @param preKey A PreKey for the destination recipient, retrieved from a server.
        /// @throws InvalidKeyException when the {@link org.whispersystems.libsignal.state.PreKeyBundle} is
        ///                             badly formatted.
        /// @throws org.whispersystems.libsignal.UntrustedIdentityException when the sender's
        ///                                                                  {@link IdentityKey} is not
        ///                                                                  trusted.
        ///
        public void Process(PreKeyBundle preKey)
        {
            lock (SessionCipher.SessionLock)
            {
                if (!_identityKeyStore.IsTrustedIdentity(_remoteAddress, preKey.GetIdentityKey(), Direction.Sending))
                {
                    throw new UntrustedIdentityException(_remoteAddress.Name, preKey.GetIdentityKey());
                }

                if (preKey.GetSignedPreKey() != null &&
                    !Curve.VerifySignature(preKey.GetIdentityKey().GetPublicKey(),
                                           preKey.GetSignedPreKey().Serialize(),
                                           preKey.GetSignedPreKeySignature()))
                {
                    throw new InvalidKeyException("Invalid signature on device key!");
                }

                if (preKey.GetSignedPreKey() == null)
                {
                    throw new InvalidKeyException("No signed prekey!");
                }

                SessionRecord      sessionRecord     = _sessionStore.LoadSession(_remoteAddress);
                EcKeyPair          ourBaseKey        = Curve.GenerateKeyPair();
                IEcPublicKey       theirSignedPreKey = preKey.GetSignedPreKey();
                IEcPublicKey       test = preKey.GetPreKey();
                May <IEcPublicKey> theirOneTimePreKey   = (test == null) ? May <IEcPublicKey> .NoValue : new May <IEcPublicKey>(test);
                May <uint>         theirOneTimePreKeyId = theirOneTimePreKey.HasValue ? new May <uint>(preKey.GetPreKeyId()) :
                                                          May <uint> .NoValue;

                AliceSignalProtocolParameters.Builder parameters = AliceSignalProtocolParameters.NewBuilder();

                parameters.SetOurBaseKey(ourBaseKey)
                .SetOurIdentityKey(_identityKeyStore.GetIdentityKeyPair())
                .SetTheirIdentityKey(preKey.GetIdentityKey())
                .SetTheirSignedPreKey(theirSignedPreKey)
                .SetTheirRatchetKey(theirSignedPreKey)
                .SetTheirOneTimePreKey(theirOneTimePreKey);

                if (!sessionRecord.IsFresh())
                {
                    sessionRecord.ArchiveCurrentState();
                }

                RatchetingSession.InitializeSession(sessionRecord.GetSessionState(), parameters.Create());

                sessionRecord.GetSessionState().SetUnacknowledgedPreKeyMessage(theirOneTimePreKeyId, preKey.GetSignedPreKeyId(), ourBaseKey.GetPublicKey());
                sessionRecord.GetSessionState().SetLocalRegistrationId(_identityKeyStore.GetLocalRegistrationId());
                sessionRecord.GetSessionState().SetRemoteRegistrationId(preKey.GetRegistrationId());
                sessionRecord.GetSessionState().SetAliceBaseKey(ourBaseKey.GetPublicKey().Serialize());

                _identityKeyStore.SaveIdentity(_remoteAddress, preKey.GetIdentityKey());

                _sessionStore.StoreSession(_remoteAddress, sessionRecord);
            }
        }
        private void InitializeSessionsV3(SessionState aliceSessionState, SessionState bobSessionState)
        {
            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();

            AliceSignalProtocolParameters aliceParameters = AliceSignalProtocolParameters.NewBuilder()
                                                            .SetOurBaseKey(aliceBaseKey)
                                                            .SetOurIdentityKey(aliceIdentityKey)
                                                            .SetTheirOneTimePreKey(May <IEcPublicKey> .NoValue)
                                                            .SetTheirRatchetKey(bobEphemeralKey.GetPublicKey())
                                                            .SetTheirSignedPreKey(bobBaseKey.GetPublicKey())
                                                            .SetTheirIdentityKey(bobIdentityKey.GetPublicKey())
                                                            .Create();

            BobSignalProtocolParameters bobParameters = BobSignalProtocolParameters.NewBuilder()
                                                        .SetOurRatchetKey(bobEphemeralKey)
                                                        .SetOurSignedPreKey(bobBaseKey)
                                                        .SetOurOneTimePreKey(May <EcKeyPair> .NoValue)
                                                        .SetOurIdentityKey(bobIdentityKey)
                                                        .SetTheirIdentityKey(aliceIdentityKey.GetPublicKey())
                                                        .SetTheirBaseKey(aliceBaseKey.GetPublicKey())
                                                        .Create();

            RatchetingSession.InitializeSession(aliceSessionState, aliceParameters);
            RatchetingSession.InitializeSession(bobSessionState, bobParameters);
        }
        public void TestRatchetingSessionAsAlice()
        {
            byte[] bobPublic = { (byte)0x05, (byte)0x2c, (byte)0xb4, (byte)0x97, (byte)0x76,
                                 (byte)0xb8, (byte)0x77, (byte)0x02, (byte)0x05, (byte)0x74,
                                 (byte)0x5a, (byte)0x3a, (byte)0x6e, (byte)0x24, (byte)0xf5,
                                 (byte)0x79, (byte)0xcd, (byte)0xb4, (byte)0xba, (byte)0x7a,
                                 (byte)0x89, (byte)0x04, (byte)0x10, (byte)0x05, (byte)0x92,
                                 (byte)0x8e, (byte)0xbb, (byte)0xad, (byte)0xc9, (byte)0xc0,
                                 (byte)0x5a, (byte)0xd4, (byte)0x58 };

            byte[] bobIdentityPublic = { (byte)0x05, (byte)0xf1, (byte)0xf4, (byte)0x38, (byte)0x74,
                                         (byte)0xf6, (byte)0x96, (byte)0x69, (byte)0x56, (byte)0xc2,
                                         (byte)0xdd, (byte)0x47, (byte)0x3f, (byte)0x8f, (byte)0xa1,
                                         (byte)0x5a, (byte)0xde, (byte)0xb7, (byte)0x1d, (byte)0x1c,
                                         (byte)0xb9, (byte)0x91, (byte)0xb2, (byte)0x34, (byte)0x16,
                                         (byte)0x92, (byte)0x32, (byte)0x4c, (byte)0xef, (byte)0xb1,
                                         (byte)0xc5, (byte)0xe6, (byte)0x26 };

            byte[] bobSignedPreKeyPublic = { (byte)0x05, (byte)0xac, (byte)0x24, (byte)0x8a, (byte)0x8f,
                                             (byte)0x26, (byte)0x3b, (byte)0xe6, (byte)0x86, (byte)0x35,
                                             (byte)0x76, (byte)0xeb, (byte)0x03, (byte)0x62, (byte)0xe2,
                                             (byte)0x8c, (byte)0x82, (byte)0x8f, (byte)0x01, (byte)0x07,
                                             (byte)0xa3, (byte)0x37, (byte)0x9d, (byte)0x34, (byte)0xba,
                                             (byte)0xb1, (byte)0x58, (byte)0x6b, (byte)0xf8, (byte)0xc7,
                                             (byte)0x70, (byte)0xcd, (byte)0x67 };

            byte[] aliceBasePublic = { (byte)0x05, (byte)0x47, (byte)0x2d, (byte)0x1f, (byte)0xb1,
                                       (byte)0xa9, (byte)0x86, (byte)0x2c, (byte)0x3a, (byte)0xf6,
                                       (byte)0xbe, (byte)0xac, (byte)0xa8, (byte)0x92, (byte)0x02,
                                       (byte)0x77, (byte)0xe2, (byte)0xb2, (byte)0x6f, (byte)0x4a,
                                       (byte)0x79, (byte)0x21, (byte)0x3e, (byte)0xc7, (byte)0xc9,
                                       (byte)0x06, (byte)0xae, (byte)0xb3, (byte)0x5e, (byte)0x03,
                                       (byte)0xcf, (byte)0x89, (byte)0x50 };

            byte[] aliceBasePrivate = { (byte)0x11, (byte)0xae, (byte)0x7c, (byte)0x64, (byte)0xd1,
                                        (byte)0xe6, (byte)0x1c, (byte)0xd5, (byte)0x96, (byte)0xb7,
                                        (byte)0x6a, (byte)0x0d, (byte)0xb5, (byte)0x01, (byte)0x26,
                                        (byte)0x73, (byte)0x39, (byte)0x1c, (byte)0xae, (byte)0x66,
                                        (byte)0xed, (byte)0xbf, (byte)0xcf, (byte)0x07, (byte)0x3b,
                                        (byte)0x4d, (byte)0xa8, (byte)0x05, (byte)0x16, (byte)0xa4,
                                        (byte)0x74, (byte)0x49 };

            byte[] aliceEphemeralPublic = { (byte)0x05, (byte)0x6c, (byte)0x3e, (byte)0x0d, (byte)0x1f,
                                            (byte)0x52, (byte)0x02, (byte)0x83, (byte)0xef, (byte)0xcc,
                                            (byte)0x55, (byte)0xfc, (byte)0xa5, (byte)0xe6, (byte)0x70,
                                            (byte)0x75, (byte)0xb9, (byte)0x04, (byte)0x00, (byte)0x7f,
                                            (byte)0x18, (byte)0x81, (byte)0xd1, (byte)0x51, (byte)0xaf,
                                            (byte)0x76, (byte)0xdf, (byte)0x18, (byte)0xc5, (byte)0x1d,
                                            (byte)0x29, (byte)0xd3, (byte)0x4b };

            byte[] aliceEphemeralPrivate = { (byte)0xd1, (byte)0xba, (byte)0x38, (byte)0xce, (byte)0xa9,
                                             (byte)0x17, (byte)0x43, (byte)0xd3, (byte)0x39, (byte)0x39,
                                             (byte)0xc3, (byte)0x3c, (byte)0x84, (byte)0x98, (byte)0x65,
                                             (byte)0x09, (byte)0x28, (byte)0x01, (byte)0x61, (byte)0xb8,
                                             (byte)0xb6, (byte)0x0f, (byte)0xc7, (byte)0x87, (byte)0x0c,
                                             (byte)0x59, (byte)0x9c, (byte)0x1d, (byte)0x46, (byte)0x20,
                                             (byte)0x12, (byte)0x48 };

            byte[] aliceIdentityPublic = { (byte)0x05, (byte)0xb4, (byte)0xa8, (byte)0x45, (byte)0x56,
                                           (byte)0x60, (byte)0xad, (byte)0xa6, (byte)0x5b, (byte)0x40,
                                           (byte)0x10, (byte)0x07, (byte)0xf6, (byte)0x15, (byte)0xe6,
                                           (byte)0x54, (byte)0x04, (byte)0x17, (byte)0x46, (byte)0x43,
                                           (byte)0x2e, (byte)0x33, (byte)0x39, (byte)0xc6, (byte)0x87,
                                           (byte)0x51, (byte)0x49, (byte)0xbc, (byte)0xee, (byte)0xfc,
                                           (byte)0xb4, (byte)0x2b, (byte)0x4a };

            byte[] aliceIdentityPrivate = { (byte)0x90, (byte)0x40, (byte)0xf0, (byte)0xd4, (byte)0xe0,
                                            (byte)0x9c, (byte)0xf3, (byte)0x8f, (byte)0x6d, (byte)0xc7,
                                            (byte)0xc1, (byte)0x37, (byte)0x79, (byte)0xc9, (byte)0x08,
                                            (byte)0xc0, (byte)0x15, (byte)0xa1, (byte)0xda, (byte)0x4f,
                                            (byte)0xa7, (byte)0x87, (byte)0x37, (byte)0xa0, (byte)0x80,
                                            (byte)0xeb, (byte)0x0a, (byte)0x6f, (byte)0x4f, (byte)0x5f,
                                            (byte)0x8f, (byte)0x58 };

            byte[] receiverChain = { (byte)0x97, (byte)0x97, (byte)0xca, (byte)0xca, (byte)0x53,
                                     (byte)0xc9, (byte)0x89, (byte)0xbb, (byte)0xe2, (byte)0x29,
                                     (byte)0xa4, (byte)0x0c, (byte)0xa7, (byte)0x72, (byte)0x70,
                                     (byte)0x10, (byte)0xeb, (byte)0x26, (byte)0x04, (byte)0xfc,
                                     (byte)0x14, (byte)0x94, (byte)0x5d, (byte)0x77, (byte)0x95,
                                     (byte)0x8a, (byte)0x0a, (byte)0xed, (byte)0xa0, (byte)0x88,
                                     (byte)0xb4, (byte)0x4d };

            IdentityKey     bobIdentityKey           = new IdentityKey(bobIdentityPublic, 0);
            IEcPublicKey    bobEphemeralPublicKey    = Curve.DecodePoint(bobPublic, 0);
            IEcPublicKey    bobSignedPreKey          = Curve.DecodePoint(bobSignedPreKeyPublic, 0);
            IEcPublicKey    aliceBasePublicKey       = Curve.DecodePoint(aliceBasePublic, 0);
            IEcPrivateKey   aliceBasePrivateKey      = Curve.DecodePrivatePoint(aliceBasePrivate);
            EcKeyPair       aliceBaseKey             = new EcKeyPair(aliceBasePublicKey, aliceBasePrivateKey);
            IEcPublicKey    aliceEphemeralPublicKey  = Curve.DecodePoint(aliceEphemeralPublic, 0);
            IEcPrivateKey   aliceEphemeralPrivateKey = Curve.DecodePrivatePoint(aliceEphemeralPrivate);
            EcKeyPair       aliceEphemeralKey        = new EcKeyPair(aliceEphemeralPublicKey, aliceEphemeralPrivateKey);
            IdentityKey     aliceIdentityPublicKey   = new IdentityKey(aliceIdentityPublic, 0);
            IEcPrivateKey   aliceIdentityPrivateKey  = Curve.DecodePrivatePoint(aliceIdentityPrivate);
            IdentityKeyPair aliceIdentityKey         = new IdentityKeyPair(aliceIdentityPublicKey, aliceIdentityPrivateKey);

            SessionState session = new SessionState();

            AliceSignalProtocolParameters parameters = AliceSignalProtocolParameters.NewBuilder()
                                                       .SetOurBaseKey(aliceBaseKey)
                                                       .SetOurIdentityKey(aliceIdentityKey)
                                                       .SetTheirIdentityKey(bobIdentityKey)
                                                       .SetTheirSignedPreKey(bobSignedPreKey)
                                                       .SetTheirRatchetKey(bobEphemeralPublicKey)
                                                       .SetTheirOneTimePreKey(May <IEcPublicKey> .NoValue)
                                                       .Create();

            RatchetingSession.InitializeSession(session, parameters);

            Assert.AreEqual <IdentityKey>(session.GetLocalIdentityKey(), aliceIdentityKey.GetPublicKey());
            Assert.AreEqual <IdentityKey>(session.GetRemoteIdentityKey(), bobIdentityKey);
            CollectionAssert.AreEqual(
                session.GetReceiverChainKey(bobEphemeralPublicKey).GetKey(), receiverChain);
        }