private ReqDHParamsArgs CreateReqDhParamsArgs(ResPQ resPQ, out PQInnerData pqInnerData)
{
Int256 pq = resPQ.Pq.ToInt256(asLittleEndian: false);
Int256 p, q;
pq.GetPrimeMultipliers(out p, out q);
Int256 newNonce = _nonceGenerator.GetNonce(32).ToInt256();
pqInnerData = new PQInnerData
{
Pq = resPQ.Pq,
P = p.ToBytes(false, true),
Q = q.ToBytes(false, true),
Nonce = resPQ.Nonce,
ServerNonce = resPQ.ServerNonce,
NewNonce = newNonce
};
byte[] data = _tlRig.Serialize(pqInnerData);
byte[] dataHash = ComputeSHA1(data);
Debug.Assert((dataHash.Length + data.Length) <= 255);
// data_with_hash := SHA1(data) + data + (any random bytes); such that the length equal 255 bytes;
var dataWithHash = new byte[255];
using (var streamer = new TLStreamer(dataWithHash))
{
streamer.Write(dataHash);
streamer.Write(data);
streamer.WriteRandomDataTillEnd();
}
PublicKey publicKey = _keyChain.GetFirst(resPQ.ServerPublicKeyFingerprints);
if (publicKey == null)
{
throw new PublicKeyNotFoundException(resPQ.ServerPublicKeyFingerprints);
}
byte[] encryptedData = _encryptionServices.RSAEncrypt(dataWithHash, publicKey);
var reqDhParamsArgs = new ReqDHParamsArgs
{
Nonce = pqInnerData.Nonce,
ServerNonce = pqInnerData.ServerNonce,
P = pqInnerData.P,
Q = pqInnerData.Q,
PublicKeyFingerprint = publicKey.Fingerprint,
EncryptedData = encryptedData
};
return reqDhParamsArgs;
}
private byte[] PrependHashAndAlign(byte[] data, int alignment)
{
int dataLength = data.Length;
byte[] dataHash = ComputeSHA1(data);
int length = HashLength + dataLength;
int mod = length%alignment;
length += mod > 0 ? alignment - mod : 0;
var dataWithHash = new byte[length];
using (var streamer = new TLStreamer(dataWithHash))
{
streamer.Write(dataHash);
streamer.Write(data);
streamer.WriteRandomDataTillEnd();
}
return dataWithHash;
}