public override MazeErrorCode onReceiveData(byte[] Data, ref byte[] ResponseData)
{
ResponseData = new byte[0];
if (LastErrorCode != MazeErrorCode.Success)
{
//don't continue if the client/server messed something up
return LastErrorCode;
}
switch (base.Step)
{
case 1:
{
//step 2
if (Data.Length != Mazing.ByteCode.Length)
{
SysLogger.Log("[MazeHandShake][Server] ByteCode Length Missmatch", SysLogType.Debug);
return MazeErrorCode.WrongByteCode;
}
for (int i = 0; i < Mazing.ByteCode.Length; i++)
{
if (Mazing.ByteCode[i] != Data[i])
{
SysLogger.Log("[MazeHandShake][Server] WrongByteCode from client", SysLogType.Debug);
return MazeErrorCode.WrongByteCode;
}
}
Step++;
break;
}
case 2:
{
if (onFindKeyInDatabase == null) //programmer error
{
SysLogger.Log("[MazeHandShake][Server] onFindKeyInDatabase is null", SysLogType.Debug);
ResponseData = GetFailResponseData(); //not encrypted, client knows this will fail
return MazeErrorCode.Error;
}
string EncHashedMsg = BitConverter.ToString(SHA512Managed.Create().ComputeHash(Data, 0, Data.Length)).Replace("-", "");
byte[] _key = new byte[0];
byte[] _salt = new byte[0];
byte[] _publicKey = new byte[0];
string _userName = "";
if (onFindKeyInDatabase(EncHashedMsg, ref _key, ref _salt, ref _publicKey, ref _userName))
{
this.PublicKeyData = TrimArray(_publicKey, Mazing.MAX_KEY_SIZE);
this.wopEx = base.GetWopEncryption(_key, _salt);
base.FinalKey = _key;
base.FinalSalt = _salt;
//let's try to decrypt the data, should go successful
wopEx.Decrypt(Data, 0, Data.Length);
if (Data.Length != _publicKey.Length)
{
SysLogger.Log("[MazeHandShake][Server] Public key length missmatch", SysLogType.Debug);
//key size not the same... strange
ResponseData = GetFailResponseData();
return MazeErrorCode.Error;
}
for (int i = 0; i < _publicKey.Length; i++)
{
if (Data[i] != _publicKey[i])
{
SysLogger.Log("[MazeHandShake][Server] Public key missmatch", SysLogType.Debug);
//public key did not match... strange
ResponseData = GetFailResponseData();
return MazeErrorCode.Error;
}
}
//encryption / public key went successful for now
this.server_Prime = BigInteger.genPseudoPrime(256, 50, new Random(BitConverter.ToInt32(_key, 0)));
byte[] primeData = server_Prime.getBytes();
wopEx.Encrypt(primeData, 0, primeData.Length);
ResponseData = primeData;
this.Username = _userName;
Step++;
}
else
{
SysLogger.Log("[MazeHandShake][Server] No user key found in database", SysLogType.Debug);
ResponseData = GetFailResponseData();
return MazeErrorCode.UserKeyNotFound;
}
break;
}
case 3:
{
//response back from client with his prime number
wopEx.Decrypt(Data, 0, Data.Length);
this.client_Prime = new BigInteger(Data);
if (this.client_Prime.isProbablePrime())
{
//verify the prime from the client
BigInteger client_Prime_test = BigInteger.genPseudoPrime(256, 50, new Random(this.server_Prime.IntValue()));
if (this.client_Prime != client_Prime_test)
{
//Attacker detected ?
SysLogger.Log("[MazeHandShake][Server] Man-In-The-Middle detected", SysLogType.Debug);
return MazeErrorCode.Error;
}
BigInteger key = base.ModKey(server_Prime, client_Prime);
//apply key to encryption
ApplyKey(wopEx, key);
return MazeErrorCode.Finished;
}
else
{
SysLogger.Log("[MazeHandShake][Server] Invalid response", SysLogType.Debug);
return MazeErrorCode.Error;
}
}
}
return MazeErrorCode.Success;
}
internal void ApplyKey(WopEx wopEx, BigInteger prime)
{
PatchKey(ref prime);
byte[] primeKey = prime.getBytes();
ApplyKey(wopEx, primeKey);
}
/// <summary>
/// Patches the key by removing the 255 in the beginning of the key
/// </summary>
/// <param name="key"></param>
private void PatchKey(ref BigInteger key)
{
byte[] _key = key.getBytes();
int count = 0;
for (int i = 0; i < _key.Length; i++, count++)
{
if (_key[i] != 255)
break;
}
if (count > 0)
{
byte[] tempKey = new byte[count];
new FastRandom(PrivateSalt.IntValue()).NextBytes(tempKey);
Array.Copy(tempKey, _key, tempKey.Length);
key = new BigInteger(_key);
}
}
public void WriteBigInteger(BigInteger BigInt)
{
byte[] temp = BigInt.getBytes();
WriteByte((byte)temp.Length);
WriteBytes(temp);
}
