public void SendHandshakeRequest(Stream handshakeRequest)
{
if (status != DhStatus.None)
{
throw new InvalidOperationException($"Wrong status {status}, expected: {DhStatus.None}");
}
byte[] privateKeyBytes = new byte[64];
byte[] publicKeyBytes = new byte[64];
rngCsp.GetBytes(privateKeyBytes);
rngCsp.GetBytes(publicKeyBytes);
privateKey = new BigInteger(privateKeyBytes);
publicKey = new BigInteger(publicKeyBytes);
BigInteger clientMod = ((privateKey * publicKey) % mod);
using (WardenStreamWriter writer = new WardenStreamWriter(handshakeRequest, true))
{
writer.Write(mark);
writer.Write(publicKeyBytes.Length);
writer.Write(publicKeyBytes);
byte[] clientModBytes = clientMod.ToByteArray();
writer.Write(clientModBytes.Length);
writer.Write(clientModBytes);
}
status = DhStatus.WaitingForServerMod;
}
void SetCipherKey()
{
if (commonKey == null)
{
throw new InvalidOperationException("Handshake sequence has not been completed. Couldn't set cipher key");
}
if (cipher.KeySize == 128)
{
using (MD5 hash = MD5.Create())
cipher.SetKey(hash.ComputeHash(commonKey));
}
else
{
throw new InvalidOperationException($"{nameof(DiffieHellmanImpl)} supports only ciphers with 128 bit keys");
}
status = DhStatus.CommonKeySet;
}
