public override MazeErrorCode onReceiveData(byte[] Data, ref byte[] ResponseData)
{
ResponseData = new byte[0];
switch (base.Step)
{
case 1:
{
if (Data.Length != 32)
{
SysLogger.Log("[MazeHandShake][Server] Receive Length missmatch", SysLogType.Debug);
return MazeErrorCode.Error;
}
wopEx = base.GetWopEncryption();
wopEx.Decrypt(Data, 0, Data.Length);
BigInteger server_prime = new BigInteger(Data);
if (server_prime.isProbablePrime())
{
//verify the prime from the server
BigInteger server_Prime_test = BigInteger.genPseudoPrime(256, 50, new Random(BitConverter.ToInt32(wopEx.Key, 0)));
if (server_prime != server_Prime_test)
{
//Attacker detected ?
SysLogger.Log("[MazeHandShake][Server] Man-In-The-Middle detected", SysLogType.Debug);
return MazeErrorCode.Error;
}
//successful
//generate another prime and send it back
BigInteger client_Prime = BigInteger.genPseudoPrime(256, 50, new Random(server_prime.IntValue()));
byte[] primeData = client_Prime.getBytes();
wopEx.Encrypt(primeData, 0, primeData.Length);
ResponseData = primeData;
BigInteger key = base.ModKey(server_prime, client_Prime);
//apply key to encryption
ApplyKey(wopEx, key);
base.FinalKey = wopEx.Key;
base.FinalSalt = wopEx.Salt;
Step++;
return MazeErrorCode.Finished;
}
else
{
//connection failed, using old keys ?
SysLogger.Log("[MazeHandShake][Server] Invalid received data", SysLogType.Debug);
return MazeErrorCode.Error;
}
}
}
return MazeErrorCode.Success;
}
//***********************************************************************
// Generates a positive BigInteger that is probably prime.
//***********************************************************************
public static BigInteger genPseudoPrime(int bits, int confidence, Random rand)
{
BigInteger result = new BigInteger();
bool done = false;
while (!done)
{
result.genRandomBits(bits, rand);
result.data[0] |= 0x01; // make it odd
// prime test
done = result.isProbablePrime(confidence);
}
return result;
}