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
});
}
public static RequestSetClientDHParams GetRequest(TServerDHParamsOk serverDhParams, byte[] newNonce, out byte[] clientAgree, out int serverTime)
{
AesHelper.ComputeAesParameters(newNonce, serverDhParams.ServerNonce, out var aesKeyData);
var dhInnerData = DeserializeResponse(serverDhParams, aesKeyData);
serverTime = dhInnerData.ServerTime;
var p = new BigInteger(1, dhInnerData.DhPrimeAsBinary);
var g = BigInteger.ValueOf(dhInnerData.G);
var dhParameters = new DHParameters(p, g);
KeyGenerationParameters kgp = new DHKeyGenerationParameters(new SecureRandom(), dhParameters);
var keyGen = GeneratorUtilities.GetKeyPairGenerator("DH");
keyGen.Init(kgp);
var clientKeyPair = keyGen.GenerateKeyPair();
var publicKey = ((DHPublicKeyParameters)clientKeyPair.Public);
var y = new BigInteger(1, dhInnerData.GAAsBinary);
Guard.That(y).IsValidDhPublicKey(dhParameters.P);
var serverPublicKey = new DHPublicKeyParameters(y, dhParameters);
var clientKeyAgree = AgreementUtilities.GetBasicAgreement("DH");
clientKeyAgree.Init(clientKeyPair.Private);
clientAgree = clientKeyAgree.CalculateAgreement(serverPublicKey).ToByteArrayUnsigned();
var clientDhInnerData = new TClientDHInnerData
{
RetryId = 0,
Nonce = serverDhParams.Nonce,
ServerNonce = serverDhParams.ServerNonce,
GBAsBinary = publicKey.Y.ToByteArray()
};
return(SerializeRequest(clientDhInnerData, aesKeyData));
}
public static ISetClientDHParamsAnswer GetResponse(RequestSetClientDHParams setClientDhParams, byte[] newNonce, AsymmetricCipherKeyPair serverKeyPair, out BigInteger serverAgree, out byte[] serverSalt)
{
AesHelper.ComputeAesParameters(newNonce, setClientDhParams.ServerNonce, out var aesKeyData);
var dhInnerData = DeserializeRequest(setClientDhParams, aesKeyData);
var dhParameters = ((DHPrivateKeyParameters)serverKeyPair.Private).Parameters;
var y = new BigInteger(dhInnerData.GBAsBinary);
Guard.That(y).IsValidDhPublicKey(dhParameters.P);
var clientPublicKey = new DHPublicKeyParameters(y, dhParameters);
var serverKeyAgree = AgreementUtilities.GetBasicAgreement("DH");
serverKeyAgree.Init(serverKeyPair.Private);
serverAgree = serverKeyAgree.CalculateAgreement(clientPublicKey);
serverSalt = SaltHelper.ComputeSalt(newNonce, setClientDhParams.ServerNonce);
return(SerializeResponse(setClientDhParams, newNonce, serverAgree));
}