public static IServerDHParams GetResponse(RequestReqDHParams reqDhParams, string privateKey, out AsymmetricCipherKeyPair serverKeyPair, out byte[] newNonce)
{
var pqInnerData = DeserializeRequest(reqDhParams, privateKey);
GeneratePandG(out var p, out var g);
KeyGenerationParameters kgp = new DHKeyGenerationParameters(new SecureRandom(), new DHParameters(p, BigInteger.ValueOf(g)));
var keyGen = GeneratorUtilities.GetKeyPairGenerator("DH");
keyGen.Init(kgp);
serverKeyPair = keyGen.GenerateKeyPair();
var publicKey = (DHPublicKeyParameters)serverKeyPair.Public;
var dhInnerData = new TServerDHInnerData
{
DhPrimeAsBinary = publicKey.Parameters.P.ToByteArray(),
Nonce = pqInnerData.Nonce,
ServerNonce = pqInnerData.ServerNonce,
G = publicKey.Parameters.G.IntValue,
GAAsBinary = publicKey.Y.ToByteArray(),
ServerTime = (int)((DateTimeOffset)DateTime.Now).ToUnixTimeSeconds()
};
newNonce = pqInnerData.NewNonce;
return(SerializeResponse(pqInnerData, dhInnerData));
}
private static TServerDHParamsOk SerializeResponse(TPQInnerData pqInnerData, TServerDHInnerData dhInnerData)
{
var dhInnerDataBuffer = Serializer.Serialize(dhInnerData);
byte[] answer;
try
{
answer = dhInnerDataBuffer.ToArray();
}
finally
{
dhInnerDataBuffer.SafeRelease();
}
var hashsum = Sha1Helper.ComputeHashsum(answer);
var answerWithHash = hashsum.Concat(answer).ToArray();
AesHelper.ComputeAesParameters(pqInnerData.NewNonce, pqInnerData.ServerNonce, out var aesKeyData);
var encryptedAnswer = AES.EncryptAes(aesKeyData, answerWithHash);
return(new TServerDHParamsOk
{
EncryptedAnswerAsBinary = encryptedAnswer,
Nonce = pqInnerData.Nonce,
ServerNonce = pqInnerData.ServerNonce
});
}
