public EncryptedMessage(byte[] authKey, byte[] plainData)
{
_authKey = authKey;
using (var ms = new MemoryStream(plainData))
{
using (var br = new BinaryReader(ms))
{
AuthKeyId = br.ReadInt64();
MsgKey = new BigInteger(br.ReadBytes(16));
// дешифруем эту дату
byte[] aesKey = CalculateAesKey(8, MsgKey.GetBytes());
byte[] aesIv = CalculateIV(8, MsgKey.GetBytes());
var aesIge = new Aes256IgeManaged(aesKey, aesIv);
Data = new EncryptedData(aesIge.Decrypt(br.ReadBytes(plainData.Length - 8 - 16)));
}
}
}
/// <summary>
/// Обработка DH параметров
/// </summary>
/// <param name="dhparams"></param>
/// <returns></returns>
private Combinator ProcessDhParams(Combinator dhparams)
{
var ea = dhparams.Get<byte[]>("encrypted_answer");
// Обновим server nonce
_serverNonce = dhparams.Get<BigInteger>("server_nonce");
// Расшифровка строки
var aes = new Aes256IgeManaged(CalculateTmpAesKey(_newNonce, _serverNonce),
CalculateTmpAesIV(_newNonce, _serverNonce));
byte[] answerWithHash = aes.Decrypt(ea);
if (answerWithHash.Length % 16 != 0)
throw new ArgumentException("Неверный ответ внутри сообщения");
byte[] answer = answerWithHash.Skip(20).ToArray();
return new Combinator(answer, "Server_DH_inner_data");
}
