/// <summary>
/// Обработка входного pq вектора
/// </summary>
/// <param name="result">req_DH_params</param>
/// <returns></returns>
private Combinator ProcessPqAnswer(Combinator result)
{
// Разложение PQ на сомножители
var u = result.Get <byte[]>("pq");
var bu = new BigInteger(u); // Входные строки в BE
BigInteger p = RhoPollard(bu);
BigInteger q = bu / p;
if (p > q)
{
BigInteger max = q;
q = p;
p = max;
}
// Генерация encrypted data
// Сформируем запрос p_q_inner_data#83c95aec pq:string p:string q:string nonce:int128 server_nonce:int128 new_nonce:int256 = P_Q_inner_data
var nonce = result.Get <BigInteger>("nonce");
var serverNonce = result.Get <BigInteger>("server_nonce");
_newNonce = BigInteger.GenerateRandom(256);
byte[] beP = p.GetBytes(); // p в BE
byte[] beQ = q.GetBytes(); // q в BE
var pQInnerData = new Combinator("p_q_inner_data", u, beP, beQ, nonce, serverNonce, _newNonce);
if (_nonce != nonce)
{
throw new ArgumentException("nonce ответа несовпадает");
}
SHA1 sha = SHA1.Create();
byte[] data = pQInnerData.Serialize();
byte[] hash = sha.ComputeHash(data);
byte[] dataWithHash;
using (var ms = new MemoryStream())
using (var bw = new BinaryWriter(ms))
{
bw.Write(hash);
bw.Write(data);
bw.Write(GenerateRandomBytes(255 - bw.BaseStream.Position));
dataWithHash = ms.ToArray();
}
byte[] encryptedData = RSAEncrypt(dataWithHash);
var fingerprint = result.Get <Combinator>("server_public_key_fingerprints").Get <long>(0);
// HACK: отпечаток ключа
return(new Combinator("req_DH_params", nonce, serverNonce, beP, beQ, fingerprint, encryptedData));
}
/// <summary>
/// Генерация клиентского запроса с параметрами Диффи-Хеллмана
/// </summary>
/// <param name="serverDh"></param>
/// <returns></returns>
private Combinator SetClientDhParams(Combinator serverDh)
{
var g = serverDh.Get <int>("g");
var dhPrime = serverDh.Get <byte[]>("dh_prime");
var gA = serverDh.Get <byte[]>("g_a");
var dh = new DiffieHellmanManaged(dhPrime, new BigInteger(g).GetBytes(), 2048);
// generate the public key of the second DH instance
byte[] gB = dh.CreateKeyExchange();
// let the second DH instance compute the shared secret using the first DH public key
_authKey = dh.DecryptKeyExchange(gA);
// Сформируем ответ
// отдаем g_b в BE
var clientDhInnerData = new Combinator("client_DH_inner_data", _nonce, _serverNonce, (long)0, gB);
byte[] s = clientDhInnerData.Serialize();
// Шифрование строки
var aes = new Aes256IgeManaged(CalculateTmpAesKey(_newNonce, _serverNonce)
, CalculateTmpAesIV(_newNonce, _serverNonce));
using (var ms = new MemoryStream())
using (var bw = new BinaryWriter(ms))
{
SHA1 sha1 = SHA1.Create();
bw.Write(sha1.ComputeHash(s));
bw.Write(s);
var r = new Random();
while (bw.BaseStream.Length % 16 != 0)
{
bw.Write((byte)r.Next());
}
s = aes.Encrypt(ms.ToArray());
}
// Сформируем ответ
var setClientDhParams = new Combinator("set_client_DH_params", _nonce, _serverNonce, s);
return(setClientDhParams);
}
/// <summary>
/// Обработка входного pq вектора
/// </summary>
/// <param name="result">req_DH_params</param>
/// <returns></returns>
private Combinator ProcessPqAnswer(Combinator result)
{
// Разложение PQ на сомножители
var u = result.Get<byte[]>("pq");
var bu = new BigInteger(u); // Входные строки в BE
BigInteger p = RhoPollard(bu);
BigInteger q = bu / p;
if (p > q)
{
BigInteger max = q;
q = p;
p = max;
}
// Генерация encrypted data
// Сформируем запрос p_q_inner_data#83c95aec pq:string p:string q:string nonce:int128 server_nonce:int128 new_nonce:int256 = P_Q_inner_data
var nonce = result.Get<BigInteger>("nonce");
var serverNonce = result.Get<BigInteger>("server_nonce");
_newNonce = BigInteger.GenerateRandom(256);
byte[] beP = p.GetBytes(); // p в BE
byte[] beQ = q.GetBytes(); // q в BE
var pQInnerData = new Combinator("p_q_inner_data", u, beP, beQ, nonce, serverNonce, _newNonce);
if (_nonce != nonce)
throw new ArgumentException("nonce ответа несовпадает");
SHA1 sha = SHA1.Create();
byte[] data = pQInnerData.Serialize();
byte[] hash = sha.ComputeHash(data);
byte[] dataWithHash;
using (var ms = new MemoryStream())
using (var bw = new BinaryWriter(ms))
{
bw.Write(hash);
bw.Write(data);
bw.Write(GenerateRandomBytes(255 - bw.BaseStream.Position));
dataWithHash = ms.ToArray();
}
byte[] encryptedData = RSAEncrypt(dataWithHash);
var fingerprint = result.Get<Combinator>("server_public_key_fingerprints").Get<long>(0);
// HACK: отпечаток ключа
return new Combinator("req_DH_params", nonce, serverNonce, beP, beQ, fingerprint, encryptedData);
}
/// <summary>
/// Генерация клиентского запроса с параметрами Диффи-Хеллмана
/// </summary>
/// <param name="serverDh"></param>
/// <returns></returns>
private Combinator SetClientDhParams(Combinator serverDh)
{
var g = serverDh.Get<int>("g");
var dhPrime = serverDh.Get<byte[]>("dh_prime");
var gA = serverDh.Get<byte[]>("g_a");
var dh = new DiffieHellmanManaged(dhPrime, new BigInteger(g).GetBytes(), 2048);
// generate the public key of the second DH instance
byte[] gB = dh.CreateKeyExchange();
// let the second DH instance compute the shared secret using the first DH public key
_authKey = dh.DecryptKeyExchange(gA);
// Сформируем ответ
// отдаем g_b в BE
var clientDhInnerData = new Combinator("client_DH_inner_data", _nonce, _serverNonce, (long)0, gB);
byte[] s = clientDhInnerData.Serialize();
// Шифрование строки
var aes = new Aes256IgeManaged(CalculateTmpAesKey(_newNonce, _serverNonce)
, CalculateTmpAesIV(_newNonce, _serverNonce));
using (var ms = new MemoryStream())
using (var bw = new BinaryWriter(ms))
{
SHA1 sha1 = SHA1.Create();
bw.Write(sha1.ComputeHash(s));
bw.Write(s);
var r = new Random();
while (bw.BaseStream.Length % 16 != 0)
bw.Write((byte)r.Next());
s = aes.Encrypt(ms.ToArray());
}
// Сформируем ответ
var setClientDhParams = new Combinator("set_client_DH_params", _nonce, _serverNonce, s);
return setClientDhParams;
}