// return big-endian authKey
public static byte[] GetAuthKey(byte[] bBytes, byte[] g_aData, byte[] dhPrimeData)
{
int position = 0;
var b = new BigInteger(bBytes.Reverse().Concat(new byte[] { 0x00 }).ToArray());
var dhPrime = TLObject.GetObject <TLString>(dhPrimeData, ref position).ToBigInteger();
position = 0;
var g_a = TLObject.GetObject <TLString>(g_aData, ref position).ToBigInteger();
var authKey = BigInteger.ModPow(g_a, b, dhPrime).ToByteArray(); // little endian + (may be) zero last byte
//remove last zero byte
if (authKey[authKey.Length - 1] == 0x00)
{
authKey = authKey.SubArray(0, authKey.Length - 1);
}
authKey = authKey.Reverse().ToArray();
if (authKey.Length > 256)
{
#if DEBUG
var authKeyInfo = new StringBuilder();
authKeyInfo.AppendLine("auth_key length > 256: " + authKey.Length);
authKeyInfo.AppendLine("g_a=" + g_a);
authKeyInfo.AppendLine("b=" + b);
authKeyInfo.AppendLine("dhPrime=" + dhPrime);
Execute.ShowDebugMessage(authKeyInfo.ToString());
#endif
var correctedAuth = new byte[256];
Array.Copy(authKey, authKey.Length - 256, correctedAuth, 0, 256);
authKey = correctedAuth;
}
else if (authKey.Length < 256)
{
#if DEBUG
var authKeyInfo = new StringBuilder();
authKeyInfo.AppendLine("auth_key length < 256: " + authKey.Length);
authKeyInfo.AppendLine("g_a=" + g_a);
authKeyInfo.AppendLine("b=" + b);
authKeyInfo.AppendLine("dhPrime=" + dhPrime);
Execute.ShowDebugMessage(authKeyInfo.ToString());
#endif
var correctedAuth = new byte[256];
Array.Copy(authKey, 0, correctedAuth, 256 - authKey.Length, authKey.Length);
for (var i = 0; i < 256 - authKey.Length; i++)
{
authKey[i] = 0;
}
authKey = correctedAuth;
}
return(authKey);
}
private void SetMinMessageId(byte[] bytes)
{
try
{
var position = 0;
var encryptedMessage = (TLEncryptedTransportMessage) new TLEncryptedTransportMessage().FromBytes(bytes, ref position);
encryptedMessage.Decrypt(AuthKey);
position = 0;
TLTransportMessage transportMessage;
transportMessage = TLObject.GetObject <TLTransportMessage>(encryptedMessage.Data, ref position);
MinMessageId = transportMessage.MessageId.Value;
System.Diagnostics.Debug.WriteLine("TCPTransport set min message_id={0} seq_no={1}", transportMessage.MessageId, transportMessage.SeqNo);
}
catch (Exception ex)
{
Execute.ShowDebugMessage("SetMessageId exception " + ex);
}
}
private static TLConfigSimple DecryptSimpleConfig(string dataString)
{
TLConfigSimple result = null;
#if !WIN_RT
var base64Chars = dataString.Where(ch =>
{
var isGoodBase64 =
(ch == '+') || (ch == '=') || (ch == '/') ||
(ch >= 'a' && ch <= 'z') ||
(ch >= 'A' && ch <= 'Z') ||
(ch >= '0' && ch <= '9');
return(isGoodBase64);
}).ToArray();
var cleanDataString = new string(base64Chars);
const int kGoodSizeBase64 = 344;
if (cleanDataString.Length != kGoodSizeBase64)
{
Log(string.Format("Bad base64 size {0} required {1}", cleanDataString.Length, kGoodSizeBase64));
return(null);
}
byte[] data = null;
try
{
data = Convert.FromBase64String(cleanDataString);
}
catch (Exception ex)
{
Log("Bad base64 bytes");
return(null);
}
const int kGoodSizeData = 256;
if (data.Length != kGoodSizeData)
{
Log(string.Format("Bad data size {0} required {1}", data.Length, kGoodSizeData));
return(null);
}
var xml = "<RSAKeyValue><Modulus>yr+18Rex2ohtVy8sroGPBwXD3DOoKCSpjDqYoXgCqB7ioln4eDCFfOBUlfXUEvM/fnKCpF46VkAftlb4VuPDeQSS/ZxZYEGqHaywlroVnXHIjgqoxiAd192xRGreuXIaUKmkwlM9JID9WS2jUsTpzQ91L8MEPLJ/4zrBwZua8W5fECwCCh2c9G5IzzBm+otMS/YKwmR1olzRCyEkyAEjXWqBI9Ftv5eG8m0VkBzOG655WIYdyV0HfDK/NWcvGqa0w/nriMD6mDjKOryamw0OP9QuYgMN0C9xMW9y8SmP4h92OAWodTYgY1hZCxdv6cs5UnW9+PWvS+WIbkh+GaWYxw==</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>";
var provider = new RSACryptoServiceProvider();
provider.FromXmlString(xml);
var parameters = provider.ExportParameters(false);
var modulus = parameters.Modulus;
var exponent = parameters.Exponent;
var dataBI = new BigInteger(data.Reverse().Concat(new byte[] { 0x00 }).ToArray());
var exponentBI = new BigInteger(exponent.Reverse().Concat(new byte[] { 0x00 }).ToArray());
var modulusBI = new BigInteger(modulus.Reverse().Concat(new byte[] { 0x00 }).ToArray());
var authKey = BigInteger.ModPow(dataBI, exponentBI, modulusBI).ToByteArray();
if (authKey[authKey.Length - 1] == 0x00)
{
authKey = authKey.SubArray(0, authKey.Length - 1);
}
authKey = authKey.Reverse().ToArray();
if (authKey.Length > 256)
{
var correctedAuth = new byte[256];
Array.Copy(authKey, authKey.Length - 256, correctedAuth, 0, 256);
authKey = correctedAuth;
}
else if (authKey.Length < 256)
{
var correctedAuth = new byte[256];
Array.Copy(authKey, 0, correctedAuth, 256 - authKey.Length, authKey.Length);
for (var i = 0; i < 256 - authKey.Length; i++)
{
authKey[i] = 0;
}
authKey = correctedAuth;
}
var key = authKey.SubArray(0, 32);
var iv = authKey.SubArray(16, 16);
var encryptedData = authKey.SubArray(32, authKey.Length - 32);
var cipher = CipherUtilities.GetCipher("AES/CBC/NOPADDING");
var param = new KeyParameter(key);
cipher.Init(false, new ParametersWithIV(param, iv));
var decryptedData = cipher.DoFinal(encryptedData);
const int kDigestSize = 16;
var hash = Utils.ComputeSHA256(decryptedData.SubArray(0, 208));
for (var i = 0; i < kDigestSize; i++)
{
if (hash[i] != decryptedData[208 + i])
{
Log("Bad digest");
return(null);
}
}
var position = 4;
var length = BitConverter.ToInt32(decryptedData, 0);
if (length <= 0 || length > 208 || length % 4 != 0)
{
Log(string.Format("Bad length {0}", length));
return(null);
}
try
{
result = TLObject.GetObject <TLConfigSimple>(decryptedData, ref position);
}
catch (Exception ex)
{
Log("Could not read configSimple");
return(null);
}
if (position != length)
{
Log(string.Format("Bad read length {0} shoud be {1}", position, length));
return(null);
}
#endif
return(result);
}
