/// <summary>
/// constructs from file
/// </summary>
/// <param name="path">file name</param>
/// <param name="passphrase">passphrase or empty string if passphrase is not required</param>
public SSH1UserAuthKey(string path, string passphrase)
{
Stream s = File.Open(path, FileMode.Open);
byte[] header = new byte[32];
s.Read(header, 0, header.Length);
if (Encoding.ASCII.GetString(header) != "SSH PRIVATE KEY FILE FORMAT 1.1\n")
{
throw new SSHException(String.Format(Strings.GetString("BrokenKeyFile"), path));
}
SSH1DataReader reader = new SSH1DataReader(ReadAll(s));
s.Close();
byte[] cipher = reader.Read(2); //first 2 bytes indicates algorithm and next 8 bytes is space
reader.Read(8);
_modulus = reader.ReadMPInt();
_publicExponent = reader.ReadMPInt();
byte[] comment = reader.ReadString();
byte[] prvt = reader.ReadAll();
//必要なら復号
CipherAlgorithm algo = (CipherAlgorithm)cipher[1];
if (algo != 0)
{
Cipher c = CipherFactory.CreateCipher(SSHProtocol.SSH1, algo, ConvertToKey(passphrase));
byte[] buf = new byte[prvt.Length];
c.Decrypt(prvt, 0, prvt.Length, buf, 0);
prvt = buf;
}
SSH1DataReader prvtreader = new SSH1DataReader(prvt);
byte[] mark = prvtreader.Read(4);
if (mark[0] != mark[2] || mark[1] != mark[3])
{
throw new SSHException(Strings.GetString("WrongPassphrase"));
}
_privateExponent = prvtreader.ReadMPInt();
_crtCoefficient = prvtreader.ReadMPInt();
_primeP = prvtreader.ReadMPInt();
_primeQ = prvtreader.ReadMPInt();
}
//RSA authentication
private void DoRSAChallengeResponse()
{
//read key
SSH1UserAuthKey key = new SSH1UserAuthKey(_param.IdentityFile, _param.Password);
SSH1DataWriter w = new SSH1DataWriter();
w.Write(key.PublicModulus);
SSH1Packet p = SSH1Packet.FromPlainPayload(PacketType.SSH_CMSG_AUTH_RSA, w.ToByteArray());
p.WriteTo(_stream, _tCipher);
p = ReceivePacket();
if (p.Type == PacketType.SSH_SMSG_FAILURE)
{
throw new SSHException(Strings.GetString("ServerRefusedRSA"));
}
else if (p.Type != PacketType.SSH_SMSG_AUTH_RSA_CHALLENGE)
{
throw new SSHException(String.Format(Strings.GetString("UnexpectedResponse"), p.Type));
}
//creating challenge
SSH1DataReader r = new SSH1DataReader(p.Data);
BigInteger challenge = key.decryptChallenge(r.ReadMPInt());
byte[] rawchallenge = RSAUtil.StripPKCS1Pad(challenge, 2).getBytes();
//building response
MemoryStream bos = new MemoryStream();
bos.Write(rawchallenge, 0, rawchallenge.Length); //!!mindtermでは頭が０かどうかで変なハンドリングがあった
bos.Write(_sessionID, 0, _sessionID.Length);
byte[] response = new MD5CryptoServiceProvider().ComputeHash(bos.ToArray());
w = new SSH1DataWriter();
w.Write(response);
p = SSH1Packet.FromPlainPayload(PacketType.SSH_CMSG_AUTH_RSA_RESPONSE, w.ToByteArray());
p.WriteTo(_stream, _tCipher);
}