Inheritance: KeyPair, ISigner, IVerifier
        /// <summary>
        /// Read OpenSSH SSH2 private key parameters.
        /// </summary>
        /// <param name="passphrase">passphrase for decrypt the key file</param>
        /// <param name="keyPair">key pair</param>
        /// <param name="comment">comment or empty if it didn't exist</param>
        public void Load(string passphrase, out KeyPair keyPair, out string comment)
        {
            if (keyFile == null)
                throw new SSHException("A key file is not loaded yet");

            KeyType keyType;
            String base64Text;
            bool encrypted = false;
            CipherAlgorithm? encryption = null;
            byte[] iv = null;
            int keySize = 0;
            int ivSize = 0;
            using (StreamReader sreader = GetStreamReader()) {
                string line = sreader.ReadLine();
                if (line == null)
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (unexpected eof)");

                if (line == PrivateKeyFileHeader.SSH2_OPENSSH_HEADER_RSA)
                    keyType = KeyType.RSA;
                else if (line == PrivateKeyFileHeader.SSH2_OPENSSH_HEADER_DSA)
                    keyType = KeyType.DSA;
                else
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (unexpected key type)");

                string footer = line.Replace("BEGIN", "END");

                StringBuilder buf = new StringBuilder();
                comment = String.Empty;
                while (true) {
                    line = sreader.ReadLine();
                    if (line == null)
                        throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (unexpected eof)");
                    if (line == footer)
                        break;
                    if (line.IndexOf(':') >= 0) {
                        if (line.StartsWith("Proc-Type:")) {
                            string[] w = line.Substring("Proc-Type:".Length).Trim().Split(',');
                            if (w.Length < 1)
                                throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (invalid Proc-Type)");
                            if (w[0] != "4")
                                throw new SSHException(Strings.GetString("UnsupportedPrivateKeyFormat")
                                            + " (" + Strings.GetString("Reason_UnsupportedProcType") + ")");
                            if (w.Length >= 2 && w[1] == "ENCRYPTED")
                                encrypted = true;
                        }
                        else if (line.StartsWith("DEK-Info:")) {
                            string[] w = line.Substring("DEK-Info:".Length).Trim().Split(',');
                            if (w.Length < 2)
                                throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (invalid DEK-Info)");
                            switch (w[0]) {
                                case "DES-EDE3-CBC":
                                    encryption = CipherAlgorithm.TripleDES;
                                    ivSize = 8;
                                    keySize = 24;
                                    break;
                                case "AES-128-CBC":
                                    encryption = CipherAlgorithm.AES128;
                                    ivSize = 16;
                                    keySize = 16;
                                    break;
                                default:
                                    throw new SSHException(Strings.GetString("UnsupportedPrivateKeyFormat")
                                            + " (" + Strings.GetString("Reason_UnsupportedEncryptionType") + ")");
                            }
                            iv = HexToByteArray(w[1]);
                            if (iv == null || iv.Length != ivSize)
                                throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (invalid IV)");
                        }
                    }
                    else
                        buf.Append(line);
                }
                base64Text = buf.ToString();
            }

            byte[] keydata = Base64.Decode(Encoding.ASCII.GetBytes(base64Text));

            if (encrypted) {
                if (!encryption.HasValue || iv == null)
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (missing encryption type or IV)");
                byte[] key = OpenSSHPassphraseToKey(passphrase, iv, keySize);
                Cipher cipher = CipherFactory.CreateCipher(SSHProtocol.SSH2, encryption.Value, key, iv);
                if (keydata.Length % cipher.BlockSize != 0)
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (invalid key data size)");
                cipher.Decrypt(keydata, 0, keydata.Length, keydata, 0);
            }

            using (MemoryStream keyDataStream = new MemoryStream(keydata, false)) {
                BERReader reader = new BERReader(keyDataStream);
                if (!reader.ReadSequence())
                    throw new SSHException(Strings.GetString("WrongPassphrase"));
                if (keyType == KeyType.RSA) {
                    /* from OpenSSL rsa_asn1.c
                     *
                     * ASN1_SIMPLE(RSA, version, LONG),
                     * ASN1_SIMPLE(RSA, n, BIGNUM),
                     * ASN1_SIMPLE(RSA, e, BIGNUM),
                     * ASN1_SIMPLE(RSA, d, BIGNUM),
                     * ASN1_SIMPLE(RSA, p, BIGNUM),
                     * ASN1_SIMPLE(RSA, q, BIGNUM),
                     * ASN1_SIMPLE(RSA, dmp1, BIGNUM),
                     * ASN1_SIMPLE(RSA, dmq1, BIGNUM),
                     * ASN1_SIMPLE(RSA, iqmp, BIGNUM)
                     */
                    BigInteger v, n, e, d, p, q, dmp1, dmq1, iqmp;
                    if (!reader.ReadInteger(out v) ||
                        !reader.ReadInteger(out n) ||
                        !reader.ReadInteger(out e) ||
                        !reader.ReadInteger(out d) ||
                        !reader.ReadInteger(out p) ||
                        !reader.ReadInteger(out q) ||
                        !reader.ReadInteger(out dmp1) ||
                        !reader.ReadInteger(out dmq1) ||
                        !reader.ReadInteger(out iqmp)) {

                        throw new SSHException(Strings.GetString("WrongPassphrase"));
                    }

                    BigInteger u = p.modInverse(q);	// inverse of p mod q
                    keyPair = new RSAKeyPair(e, d, n, u, p, q);
                }
                else if (keyType == KeyType.DSA) {
                    /* from OpenSSL dsa_asn1.c
                     *
                     * ASN1_SIMPLE(DSA, version, LONG),
                     * ASN1_SIMPLE(DSA, p, BIGNUM),
                     * ASN1_SIMPLE(DSA, q, BIGNUM),
                     * ASN1_SIMPLE(DSA, g, BIGNUM),
                     * ASN1_SIMPLE(DSA, pub_key, BIGNUM),
                     * ASN1_SIMPLE(DSA, priv_key, BIGNUM)
                     */
                    BigInteger v, p, q, g, y, x;
                    if (!reader.ReadInteger(out v) ||
                        !reader.ReadInteger(out p) ||
                        !reader.ReadInteger(out q) ||
                        !reader.ReadInteger(out g) ||
                        !reader.ReadInteger(out y) ||
                        !reader.ReadInteger(out x)) {

                        throw new SSHException(Strings.GetString("WrongPassphrase"));
                    }
                    keyPair = new DSAKeyPair(p, g, q, y, x);
                }
                else {
                    throw new SSHException("Unknown file type. This should not happen.");
                }
            }
        }
        /// <summary>
        /// Read PuTTY SSH2 private key parameters.
        /// </summary>
        /// <param name="passphrase">passphrase for decrypt the key file</param>
        /// <param name="keyPair">key pair</param>
        /// <param name="comment">comment or empty if it didn't exist</param>
        public void Load(string passphrase, out KeyPair keyPair, out string comment)
        {
            if (keyFile == null)
                throw new SSHException("A key file is not loaded yet");

            int version;
            string keyTypeName;
            KeyType keyType;
            string encryptionName;
            CipherAlgorithm? encryption;
            byte[] publicBlob;
            byte[] privateBlob;
            string privateMac;
            string privateHash;

            using (StreamReader sreader = GetStreamReader()) {
                //*** Read header and key type
                ReadHeaderLine(sreader, out version, out keyTypeName);

                if (keyTypeName == "ssh-rsa")
                    keyType = KeyType.RSA;
                else if (keyTypeName == "ssh-dss")
                    keyType = KeyType.DSA;
                else
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (unexpected key type)");

                //*** Read encryption
                ReadItemLine(sreader, "Encryption", out encryptionName);

                if (encryptionName == "aes256-cbc")
                    encryption = CipherAlgorithm.AES256;
                else if (encryptionName == "none")
                    encryption = null;
                else
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (unexpected encryption)");

                //*** Read comment
                ReadItemLine(sreader, "Comment", out comment);

                //*** Read public lines
                string publicLinesStr;
                ReadItemLine(sreader, "Public-Lines", out publicLinesStr);
                int publicLines;
                if (!Int32.TryParse(publicLinesStr, out publicLines) || publicLines < 0)
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (invalid public lines)");

                ReadBlob(sreader, publicLines, out publicBlob);

                //*** Read private lines
                string privateLinesStr;
                ReadItemLine(sreader, "Private-Lines", out privateLinesStr);
                int privateLines;
                if (!Int32.TryParse(privateLinesStr, out privateLines) || privateLines < 0)
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (invalid private lines)");

                ReadBlob(sreader, privateLines, out privateBlob);

                //*** Read private MAC
                ReadPrivateMACLine(sreader, version, out privateMac, out privateHash);
            }

            if (encryption.HasValue) {
                byte[] key = PuTTYPassphraseToKey(passphrase);
                byte[] iv = new byte[16];
                Cipher cipher = CipherFactory.CreateCipher(SSHProtocol.SSH2, encryption.Value, key, iv);
                if (privateBlob.Length % cipher.BlockSize != 0)
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (invalid key data size)");
                cipher.Decrypt(privateBlob, 0, privateBlob.Length, privateBlob, 0);
            }

            bool verified = Verify(version, privateMac, privateHash,
                                passphrase, keyTypeName, encryptionName, comment, publicBlob, privateBlob);
            if (!verified) {
                if (encryption.HasValue)
                    throw new SSHException(Strings.GetString("WrongPassphrase"));
                else
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (HMAC verification failed)");
            }

            if (keyType == KeyType.RSA) {
                SSH2DataReader reader = new SSH2DataReader(publicBlob);
                string magic = reader.ReadString();
                if (magic != "ssh-rsa")
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (missing magic)");

                BigInteger e = reader.ReadMPInt();
                BigInteger n = reader.ReadMPInt();

                reader = new SSH2DataReader(privateBlob);
                BigInteger d = reader.ReadMPInt();
                BigInteger p = reader.ReadMPInt();
                BigInteger q = reader.ReadMPInt();
                BigInteger iqmp = reader.ReadMPInt();

                BigInteger u = p.ModInverse(q);

                keyPair = new RSAKeyPair(e, d, n, u, p, q);
            }
            else if (keyType == KeyType.DSA) {
                SSH2DataReader reader = new SSH2DataReader(publicBlob);
                string magic = reader.ReadString();
                if (magic != "ssh-dss")
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (missing magic)");

                BigInteger p = reader.ReadMPInt();
                BigInteger q = reader.ReadMPInt();
                BigInteger g = reader.ReadMPInt();
                BigInteger y = reader.ReadMPInt();

                reader = new SSH2DataReader(privateBlob);
                BigInteger x = reader.ReadMPInt();

                keyPair = new DSAKeyPair(p, g, q, y, x);
            }
            else {
                throw new SSHException("Unknown file type. This should not happen.");
            }
        }
        /// <summary>
        /// Read SSH.com SSH2 private key parameters.
        /// </summary>
        /// <param name="passphrase">passphrase for decrypt the key file</param>
        /// <param name="keyPair">key pair</param>
        /// <param name="comment">comment or empty if it didn't exist</param>
        /// <exception cref="SSHException">failed to parse</exception>
        public void Load(string passphrase, out KeyPair keyPair, out string comment)
        {
            if (keyFile == null)
                throw new SSHException("A key file is not loaded yet");

            String base64Text;
            using (StreamReader sreader = GetStreamReader()) {
                string line = sreader.ReadLine();
                if (line == null || line != PrivateKeyFileHeader.SSH2_SSHCOM_HEADER)
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (missing header)");

                StringBuilder buf = new StringBuilder();
                comment = String.Empty;
                while (true) {
                    line = sreader.ReadLine();
                    if (line == null)
                        throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (unexpected eof)");
                    if (line == PrivateKeyFileHeader.SSH2_SSHCOM_FOOTER)
                        break;
                    if (line.IndexOf(':') >= 0) {
                        if (line.StartsWith("Comment: "))
                            comment = line.Substring("Comment: ".Length);
                    }
                    else if (line[line.Length - 1] == '\\')
                        buf.Append(line, 0, line.Length - 1);
                    else
                        buf.Append(line);
                }
                base64Text = buf.ToString();
            }

            byte[] keydata = Base64.Decode(Encoding.ASCII.GetBytes(base64Text));
            //Debug.WriteLine(DebugUtil.DumpByteArray(keydata));

            SSH2DataReader reader = new SSH2DataReader(keydata);
            int magic = reader.ReadInt32();
            if (magic != MAGIC)
                throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (magic code unmatched)");
            int privateKeyLen = reader.ReadInt32();
            string type = reader.ReadString();

            string ciphername = reader.ReadString();
            int bufLen = reader.ReadInt32();
            if (ciphername != "none") {
                CipherAlgorithm algo = CipherFactory.SSH2NameToAlgorithm(ciphername);
                byte[] key = SSH2UserAuthKey.PassphraseToKey(passphrase, CipherFactory.GetKeySize(algo));
                Cipher c = CipherFactory.CreateCipher(SSHProtocol.SSH2, algo, key);
                byte[] tmp = new Byte[keydata.Length - reader.Offset];
                c.Decrypt(keydata, reader.Offset, keydata.Length - reader.Offset, tmp, 0);
                reader = new SSH2DataReader(tmp);
            }

            int parmLen = reader.ReadInt32();
            if (parmLen < 0 || parmLen > reader.RemainingDataLength)
                throw new SSHException(Strings.GetString("WrongPassphrase"));

            if (type.IndexOf("if-modn") != -1) {
                //mindterm mistaken this order of BigIntegers
                BigInteger e = ReadBigIntWithBits(reader);
                BigInteger d = ReadBigIntWithBits(reader);
                BigInteger n = ReadBigIntWithBits(reader);
                BigInteger u = ReadBigIntWithBits(reader);
                BigInteger p = ReadBigIntWithBits(reader);
                BigInteger q = ReadBigIntWithBits(reader);
                keyPair = new RSAKeyPair(e, d, n, u, p, q);
            }
            else if (type.IndexOf("dl-modp") != -1) {
                if (reader.ReadInt32() != 0)
                    throw new SSHException(Strings.GetString("UnsupportedPrivateKeyFormat")
                            + " (" + Strings.GetString("Reason_UnsupportedDSAKeyFormat") + ")");
                BigInteger p = ReadBigIntWithBits(reader);
                BigInteger g = ReadBigIntWithBits(reader);
                BigInteger q = ReadBigIntWithBits(reader);
                BigInteger y = ReadBigIntWithBits(reader);
                BigInteger x = ReadBigIntWithBits(reader);
                keyPair = new DSAKeyPair(p, g, q, y, x);
            }
            else
                throw new SSHException(Strings.GetString("UnsupportedAuthenticationMethod"));
        }
        /// <summary>
        /// Read private key parameters.
        /// </summary>
        /// <param name="passphrase">passphrase for decrypt the key file</param>
        /// <param name="keyPair">key pair</param>
        /// <param name="comment">comment or empty if it didn't exist</param>
        public void Load(string passphrase, out KeyPair keyPair, out string comment)
        {
            PEMKeyType keyType;
            String base64Text;
            bool encrypted = false;
            CipherAlgorithm? encryption = null;
            byte[] iv = null;
            int keySize = 0;
            int ivSize = 0;

            using (StreamReader sreader = GetStreamReader()) {
                string line = sreader.ReadLine();
                if (line == null)
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (unexpected eof)");

                if (line == PrivateKeyFileHeader.SSH2_OPENSSH_HEADER_RSA)
                    keyType = PEMKeyType.RSA;
                else if (line == PrivateKeyFileHeader.SSH2_OPENSSH_HEADER_DSA)
                    keyType = PEMKeyType.DSA;
                else if (line == PrivateKeyFileHeader.SSH2_OPENSSH_HEADER_ECDSA)
                    keyType = PEMKeyType.ECDSA;
                else
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (unexpected key type)");

                string footer = line.Replace("BEGIN", "END");

                StringBuilder buf = new StringBuilder();
                comment = String.Empty;
                while (true) {
                    line = sreader.ReadLine();
                    if (line == null)
                        throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (unexpected eof)");
                    if (line == footer)
                        break;
                    if (line.IndexOf(':') >= 0) {
                        if (line.StartsWith("Proc-Type:")) {
                            string[] w = line.Substring("Proc-Type:".Length).Trim().Split(',');
                            if (w.Length < 1)
                                throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (invalid Proc-Type)");
                            if (w[0] != "4")
                                throw new SSHException(Strings.GetString("UnsupportedPrivateKeyFormat")
                                            + " (" + Strings.GetString("Reason_UnsupportedProcType") + ")");
                            if (w.Length >= 2 && w[1] == "ENCRYPTED")
                                encrypted = true;
                        }
                        else if (line.StartsWith("DEK-Info:")) {
                            string[] w = line.Substring("DEK-Info:".Length).Trim().Split(',');
                            if (w.Length < 2)
                                throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (invalid DEK-Info)");
                            switch (w[0]) {
                                case "DES-EDE3-CBC":
                                    encryption = CipherAlgorithm.TripleDES;
                                    ivSize = 8;
                                    keySize = 24;
                                    break;
                                case "AES-128-CBC":
                                    encryption = CipherAlgorithm.AES128;
                                    ivSize = 16;
                                    keySize = 16;
                                    break;
                                default:
                                    throw new SSHException(Strings.GetString("UnsupportedPrivateKeyFormat")
                                            + " (" + Strings.GetString("Reason_UnsupportedEncryptionType") + ")");
                            }
                            iv = HexToByteArray(w[1]);
                            if (iv == null || iv.Length != ivSize)
                                throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (invalid IV)");
                        }
                    }
                    else
                        buf.Append(line);
                }
                base64Text = buf.ToString();
            }

            byte[] keydata = Base64.Decode(Encoding.ASCII.GetBytes(base64Text));

            if (encrypted) {
                if (!encryption.HasValue || iv == null)
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (missing encryption type or IV)");
                byte[] key = PassphraseToKey(passphrase, iv, keySize);
                Cipher cipher = CipherFactory.CreateCipher(SSHProtocol.SSH2, encryption.Value, key, iv);
                if (keydata.Length % cipher.BlockSize != 0)
                    throw new SSHException(Strings.GetString("NotValidPrivateKeyFile") + " (invalid key data size)");
                cipher.Decrypt(keydata, 0, keydata.Length, keydata, 0);
            }

            using (MemoryStream keyDataStream = new MemoryStream(keydata, false)) {
                BERReader reader = new BERReader(keyDataStream);
                if (!reader.ReadSequence())
                    throw new SSHException(Strings.GetString("WrongPassphrase"));
                if (keyType == PEMKeyType.RSA) {
                    /* from OpenSSL rsa_asn1.c
                     *
                     * ASN1_SIMPLE(RSA, version, LONG),
                     * ASN1_SIMPLE(RSA, n, BIGNUM),
                     * ASN1_SIMPLE(RSA, e, BIGNUM),
                     * ASN1_SIMPLE(RSA, d, BIGNUM),
                     * ASN1_SIMPLE(RSA, p, BIGNUM),
                     * ASN1_SIMPLE(RSA, q, BIGNUM),
                     * ASN1_SIMPLE(RSA, dmp1, BIGNUM),
                     * ASN1_SIMPLE(RSA, dmq1, BIGNUM),
                     * ASN1_SIMPLE(RSA, iqmp, BIGNUM)
                     */
                    BigInteger v, n, e, d, p, q, dmp1, dmq1, iqmp;
                    if (!reader.ReadInteger(out v) ||
                        !reader.ReadInteger(out n) ||
                        !reader.ReadInteger(out e) ||
                        !reader.ReadInteger(out d) ||
                        !reader.ReadInteger(out p) ||
                        !reader.ReadInteger(out q) ||
                        !reader.ReadInteger(out dmp1) ||
                        !reader.ReadInteger(out dmq1) ||
                        !reader.ReadInteger(out iqmp)) {

                        throw new SSHException(Strings.GetString("WrongPassphrase"));
                    }

                    BigInteger u = p.ModInverse(q);	// inverse of p mod q
                    keyPair = new RSAKeyPair(e, d, n, u, p, q);
                }
                else if (keyType == PEMKeyType.DSA) {
                    /* from OpenSSL dsa_asn1.c
                     *
                     * ASN1_SIMPLE(DSA, version, LONG),
                     * ASN1_SIMPLE(DSA, p, BIGNUM),
                     * ASN1_SIMPLE(DSA, q, BIGNUM),
                     * ASN1_SIMPLE(DSA, g, BIGNUM),
                     * ASN1_SIMPLE(DSA, pub_key, BIGNUM),
                     * ASN1_SIMPLE(DSA, priv_key, BIGNUM)
                     */
                    BigInteger v, p, q, g, y, x;
                    if (!reader.ReadInteger(out v) ||
                        !reader.ReadInteger(out p) ||
                        !reader.ReadInteger(out q) ||
                        !reader.ReadInteger(out g) ||
                        !reader.ReadInteger(out y) ||
                        !reader.ReadInteger(out x)) {

                        throw new SSHException(Strings.GetString("WrongPassphrase"));
                    }
                    keyPair = new DSAKeyPair(p, g, q, y, x);
                }
                else if (keyType == PEMKeyType.ECDSA) {
                    /* from OpenSSL ec_asn1.c
                     *
                     * ASN1_SIMPLE(EC_PRIVATEKEY, version, LONG),
                     * ASN1_SIMPLE(EC_PRIVATEKEY, privateKey, ASN1_OCTET_STRING),
                     * ASN1_EXP_OPT(EC_PRIVATEKEY, parameters, ECPKPARAMETERS, 0),
                     *   ------
                     *   ASN1_SIMPLE(ECPKPARAMETERS, value.named_curve, ASN1_OBJECT),
                     *   ------
                     * ASN1_EXP_OPT(EC_PRIVATEKEY, publicKey, ASN1_BIT_STRING, 1)
                     */
                    int len;
                    byte[] privateKey;
                    byte[] publicKey;
                    string namedCurve;
                    BigInteger v;
                    if (!reader.ReadInteger(out v) ||
                        !reader.ReadOctetString(out privateKey) ||
                        !reader.ReadTag(BERReader.TagClass.ContextSpecific, true, 0, out len) ||
                        !reader.ReadObjectIdentifier(out namedCurve) ||
                        !reader.ReadTag(BERReader.TagClass.ContextSpecific, true, 1, out len) ||
                        !reader.ReadBitString(out publicKey)) {

                        throw new SSHException(Strings.GetString("WrongPassphrase"));
                    }

                    EllipticCurve curve = EllipticCurve.FindByOID(namedCurve);
                    if (curve == null) {
                        throw new SSHException(Strings.GetString("UnsupportedEllipticCurveInKeyPair"));
                    }

                    ECPoint ecPublicKeyPoint;
                    if (!ECPoint.Parse(publicKey, curve, out ecPublicKeyPoint)) {
                        throw new SSHException(Strings.GetString("KeysAreBroken"));
                    }

                    var ecKeyPair = new ECDSAKeyPair(curve, new ECDSAPublicKey(curve, ecPublicKeyPoint), new BigInteger(privateKey));

                    if (!ecKeyPair.CheckKeyConsistency()) {
                        throw new SSHException(Strings.GetString("KeysAreBroken"));
                    }

                    keyPair = ecKeyPair;
                }
                else {
                    throw new SSHException("Unknown file type. This should not happen.");
                }
            }
        }