async Task SendData(byte[] Data, IncomingClient client)
{
try
{
byte[] nonce = new byte[8];
Common.rngCsp.GetBytes(nonce);
byte[] counter_sender_data = Utils.GetLengthAsBytes((int)client.PacketCounter).Concat(Data).ToArray();
byte[] CryptedCounterSenderData = Salsa20.ProcessSalsa20(counter_sender_data, client.TransportKey, nonce, 0);
byte[] HMAC = (new HMACSHA256(client.AuthenticationKey)).ComputeHash(CryptedCounterSenderData).Take(16).ToArray();
byte[] NONCE_MAC_DATA = nonce.Concat(HMAC).Concat(CryptedCounterSenderData).ToArray();
await PacketSender.SendTransportPacket(client.client.GetStream(), TransportPacketType.DataCrypted, NONCE_MAC_DATA);
}
catch { }
}
public void StartListeningInternal()
{
try
{
listener.Start();
while (Constants.ApplicationRunning)
{
IncomingClient _inClient = new IncomingClient();
_inClient.client = listener.AcceptTcpClient();
Constants.SERVER_GLOBAL_TOTAL_ACC_CONNS++;
Hash hsh = new Hash(Utils.GenerateUniqueGUID_Bytes(8));
_inClient.Identifier = hsh;
ThreadList.Add(hsh, _inClient);
Task.Run(() => { ClientHandler(_inClient); });
/*Thread clientThread = new Thread(new ParameterizedThreadStart(ClientHandler));
_inClient.thread = clientThread;
clientThread.Start(_inClient);*/
}
}
catch (Exception ex)
{
DisplayUtils.Display("Listening", ex);
}
}
//System.Diagnostics.Stopwatch sw_timer = new System.Diagnostics.Stopwatch();
async Task ProcessIncomingUserInternal(IncomingClient iClient, TransportPacket p)
{
BinaryReader reader = new BinaryReader(iClient.client.GetStream());
//BinaryWriter writer = new BinaryWriter(iClient.client.GetStream());
NetworkStream writer = iClient.client.GetStream();
//DisplayUtils.Display("Packet Received: " + p.Type);
switch (p.Type)
{
case TransportPacketType.Initialize:
iClient.ConnTimeStart = DateTime.UtcNow.Ticks;
//DisplayUtils.Display("Init Received", DisplayType.Info);
if ((!iClient.WorkProven) && (!iClient.KeyExchanged))
{
await PacketSender.SendTransportPacket(writer, TransportPacketType.WorkProofRequest, iClient.WorkTask);
}
break;
case TransportPacketType.WorkProofKeyResponse:
//DisplayUtils.Display("WorkProofResponse Received : " + p.Data.Length, DisplayType.Info);
if ((!iClient.WorkProven) && (!iClient.KeyExchanged))
{
if (p.Data.Length == 60)
{
Constants.SERVER_GLOBAL_AUTH_PACKETS++;
byte[] Proof = new byte[4];
byte[] DHClientPublic = new byte[32];
byte[] AuthRandom = new byte[24];
Array.Copy(p.Data, 0, Proof, 0, 4);
Array.Copy(p.Data, 4, DHClientPublic, 0, 32);
Array.Copy(p.Data, 36, AuthRandom, 0, 24);
iClient.WorkProven = WorkProof.VerifyProof(iClient.WorkTask, Proof, Constants.Difficulty);
if (iClient.WorkProven)
{
//DisplayUtils.Display("Work Proved", DisplayType.Info);
Common.rngCsp.GetBytes(iClient.DHRandomBytes);
iClient.DHPrivateKey = Curve25519.ClampPrivateKey(iClient.DHRandomBytes);
iClient.DHPublicKey = Curve25519.GetPublicKey(iClient.DHPrivateKey);
// Generate the shared-secret using the provided client Public Key
byte[] sharedSecret = (new SHA512Managed()).ComputeHash(Curve25519.GetSharedSecret(iClient.DHPrivateKey, DHClientPublic));
Array.Copy(sharedSecret, iClient.TransportKey, 32);
Array.Copy(sharedSecret, 32, iClient.AuthenticationKey, 0, 32);
// Sign the data using the Node-Private key, so that the client can know that the connection is secure.
// This thwarts MITM attacks.
byte[] Client_ServerAuthSignature = nodeConfig.SignDataWithPrivateKey(AuthRandom);
// 64 bytes Signature
byte[] signPlain = Client_ServerAuthSignature;
if (signPlain.Length != 64) throw new Exception("Improbable Assertion failed : 1");
// Encrypt the Signature and Identifier using Salsa20
byte[] signCrypted = Salsa20.ProcessSalsa20(signPlain, iClient.TransportKey, new byte[8], 0);
// EtM -> Encrypt then MAC
byte[] signMAC = (new HMACSHA256(iClient.AuthenticationKey)).ComputeHash(signCrypted);
// SERVER_PUBLIC[32] || signMAC[32] || signCrypted[64] => 128 bytes
byte[] KeysSignature = iClient.DHPublicKey.Concat(signMAC).Concat(signCrypted).ToArray();
await PacketSender.SendTransportPacket(writer, TransportPacketType.ServerPublicTransfer, KeysSignature);
}
else
{
DisplayUtils.Display("Work Proof invalid : " + p.Data.Length, DisplayType.Exception);
await PacketSender.SendTransportPacket(writer, TransportPacketType.InvalidAuthDisconnect, new byte[0]);
}
}
else
{
DisplayUtils.Display("Invalid Packet Length : " + p.Data.Length, DisplayType.Exception);
await PacketSender.SendTransportPacket(writer, TransportPacketType.InvalidAuthDisconnect, new byte[0]);
}
}
break;
case TransportPacketType.KeyExComplete_1:
if ((iClient.WorkProven) && (!iClient.KeyExchanged))
{
if (p.Data.Length == 128)
{
// cryptedSigPK_MAC[32] || cryptedSigPK[96] = 128 bytes
byte[] cryptedSigPK_MAC = new byte[32];
byte[] cryptedSigPK = new byte[96];
Array.Copy(p.Data, 0, cryptedSigPK_MAC, 0, 32);
Array.Copy(p.Data, 32, cryptedSigPK, 0, 96);
byte[] cryptedSigPK_MAC_Expected = (new HMACSHA256(iClient.AuthenticationKey)).ComputeHash(cryptedSigPK);
if (CryptoBytes.ConstantTimeEquals(cryptedSigPK_MAC_Expected, cryptedSigPK_MAC))
{
byte[] workSignPK = Salsa20.ProcessSalsa20(cryptedSigPK, iClient.TransportKey, new byte[8], 0);
// workSignPK[96] = workSign[64] || nodeConfig.PublicKey[32]
byte[] workSign = new byte[64];
byte[] remotePK = new byte[32];
Array.Copy(workSignPK, 0, workSign, 0, 64);
Array.Copy(workSignPK, 64, remotePK, 0, 32);
bool serverVerified = Ed25519.Verify(workSign, iClient.WorkTask, remotePK);
if (serverVerified)
{
iClient.PublicKey = new Hash(remotePK);
if (Constants.NetworkVerbosity >= Verbosity.Info)
{
/*DisplayUtils.Display(NodeSocketData.GetString(nodeSocketData) + " : Key Exchanged 1: Shared KEY [TransportKey] : {" +
(HexUtil.ToString(TransportKey)) + "}", DisplayType.Info);*/
DisplayUtils.Display(iClient.PublicKey.ToString() + " Client Authenticated", DisplayType.Info);
}
await PacketSender.SendTransportPacket(writer, TransportPacketType.KeyExComplete_2, new byte[0]);
iClient.KeyExchanged = true;
IncomingConnections.Add(iClient.PublicKey, iClient);
DisplayUtils.Display("Exchange Complete 2, Shared KEY [TransportKey] : " + HexUtil.ToString(iClient.TransportKey), DisplayType.Info);
}
}
}
}
break;
case TransportPacketType.DataCrypted:
if (iClient.KeyExchanged && p.Data.Length > 28)
{
Constants.SERVER_GLOBAL_DATA_PACKETS++;
byte[] nonce = new byte[8];
byte[] hmac = new byte[16];
byte[] crypted_data = new byte[p.Data.Length - 24];
Array.Copy(p.Data, 0, nonce, 0, 8);
Array.Copy(p.Data, 8, hmac, 0, 16);
Array.Copy(p.Data, 24, crypted_data, 0, crypted_data.Length);
byte[] MAC_EXPECTED = (new HMACSHA256(iClient.AuthenticationKey)).ComputeHash(crypted_data).Take(16).ToArray();
if (CryptoBytes.ConstantTimeEquals(MAC_EXPECTED, hmac))
{
byte[] DeCryptedData = Salsa20.ProcessSalsa20(crypted_data, iClient.TransportKey, nonce, 0);
byte[] counter = new byte[4];
byte[] rec_data = new byte[p.Data.Length - 28];
Array.Copy(DeCryptedData, 0, counter, 0, 4);
Array.Copy(DeCryptedData, 4, rec_data, 0, rec_data.Length);
Array.Copy(DeCryptedData, 0, counter, 0, 4);
Array.Copy(DeCryptedData, 4, rec_data, 0, rec_data.Length);
NetworkPacket np = new NetworkPacket();
np.Deserialize(rec_data);
if (iClient.PublicKey == np.PublicKeySource)
{
if (PacketReceived != null)
PacketReceived(np);
}
else
{
DisplayUtils.Display("Packet Source Incoming Mismatch", DisplayType.Warning);
}
}
else
{
DisplayUtils.Display("HMAC FAILED : ");
}
}
break;
}
}