public override object Deserialize(Stream aStream)
{
/* check for required parameters */
if (aStream == null) {
throw new ArgumentNullException("aStream");
}
/* reading unencrypted part */
BlobParser parser = new BlobParser(aStream);
parser.ReadBytes((uint)FILE_HEADER_LINE.Length + 2); //Skipping header line
byte cipherType = parser.ReadByte();
if (cipherType != SSH_CIPHER_3DES && cipherType != SSH_CIPHER_NONE) {
//TripleDes is the only encryption supported
throw new KeyFormatterException("Unsupported cypherType: " + cipherType);
}
parser.ReadInt(); //reserved
/* reading public key */
AsymmetricKeyParameter aPublicKeyParameter =
parser.ReadSsh1PublicKeyData(false);
String keyComment = parser.ReadString();
/* reading private key */
byte[] inputBuffer = new byte[aStream.Length];
aStream.Read(inputBuffer, 0, inputBuffer.Length);
byte[] ouputBuffer;
try {
if (cipherType == 3) {
/* private key is 3DES encrypted */
PasswordFinder pwFinder = null;
if (GetPassphraseCallbackMethod != null) {
pwFinder = new PasswordFinder(GetPassphraseCallbackMethod);
}
byte[] keydata;
try {
using (MD5 md5 = MD5.Create()) {
char[] md5Buffer = pwFinder.GetPassword();
keydata = md5.ComputeHash(Encoding.ASCII.GetBytes(md5Buffer));
}
} catch (PasswordException ex) {
if (GetPassphraseCallbackMethod == null) {
throw new CallbackNullException();
}
throw new KeyFormatterException("see inner exception", ex);
}
/* decryption */
DesSsh1Engine desEngine = new DesSsh1Engine();
desEngine.Init(false, new KeyParameter(keydata));
BufferedBlockCipher bufferedBlockCipher = new BufferedBlockCipher(desEngine);
ouputBuffer = bufferedBlockCipher.ProcessBytes(inputBuffer);
} else {
/* private key is stored in plain text */
ouputBuffer = inputBuffer;
}
var privateKeyParser = new BlobParser(ouputBuffer);
/* checking result of decryption */
byte[] resultCheck = privateKeyParser.ReadBytes(4);
if (resultCheck[0] != resultCheck[2] || resultCheck[1] != resultCheck[3]) {
throw new KeyFormatterException("bad passphrase");
}
/* reading private key */
var keyPair = privateKeyParser.ReadSsh1KeyData(aPublicKeyParameter);
SshKey key = new SshKey(SshVersion.SSH1, keyPair);
key.Comment = keyComment;
return key;
} catch (KeyFormatterException) {
throw;
} catch (Exception ex) {
throw new KeyFormatterException("see inner exception", ex);
}
}
public override void Serialize(Stream aStream, object aObject)
{
/* check for required parameters */
if (aStream == null) {
throw new ArgumentNullException("aStream");
}
if (aObject == null) {
throw new ArgumentNullException("aObject");
}
PasswordFinder pwFinder = null;
if (GetPassphraseCallbackMethod != null) {
pwFinder = new PasswordFinder(GetPassphraseCallbackMethod);
}
PinnedArray<char> passphrase = null;
if (pwFinder != null) {
passphrase = new PinnedArray<char>(0);
passphrase.Data = pwFinder.GetPassword();
}
byte cipherType;
if (passphrase == null || passphrase.Data.Length == 0) {
cipherType = SSH_CIPHER_NONE;
} else {
cipherType = SSH_CIPHER_3DES;
}
BlobBuilder builder = new BlobBuilder();
ISshKey sshKey = aObject as ISshKey;
RsaKeyParameters publicKeyParams = sshKey.GetPublicKeyParameters()
as RsaKeyParameters;
RsaPrivateCrtKeyParameters privateKeyParams = sshKey.GetPrivateKeyParameters()
as RsaPrivateCrtKeyParameters;
/* writing info headers */
builder.AddBytes(Encoding.ASCII.GetBytes(FILE_HEADER_LINE + "\n"));
builder.AddByte(0); //end of string
builder.AddByte(cipherType); //cipher
builder.AddInt(0); //reserved
/* writing public key */
builder.AddInt(sshKey.Size);
builder.AddSsh1BigIntBlob(publicKeyParams.Modulus);
builder.AddSsh1BigIntBlob(publicKeyParams.Exponent);
builder.AddStringBlob(sshKey.Comment);
/* writing private key */
BlobBuilder privateKeyBuilder = new BlobBuilder();
/* adding some control values */
Random random = new Random();
byte[] resultCheck = new byte[2];
random.NextBytes(resultCheck);
privateKeyBuilder.AddByte(resultCheck[0]);
privateKeyBuilder.AddByte(resultCheck[1]);
privateKeyBuilder.AddByte(resultCheck[0]);
privateKeyBuilder.AddByte(resultCheck[1]);
privateKeyBuilder.AddSsh1BigIntBlob(privateKeyParams.Exponent);
privateKeyBuilder.AddSsh1BigIntBlob(privateKeyParams.DQ);
privateKeyBuilder.AddSsh1BigIntBlob(privateKeyParams.P);
privateKeyBuilder.AddSsh1BigIntBlob(privateKeyParams.Q);
if (cipherType == SSH_CIPHER_NONE) {
/* plain-text */
builder.AddBytes(privateKeyBuilder.GetBlobAsPinnedByteArray().Data);
} else {
byte[] keydata;
using (MD5 md5 = MD5.Create()) {
keydata = md5.ComputeHash(Encoding.ASCII.GetBytes(passphrase.Data));
}
/* encryption */
DesSsh1Engine desEngine = new DesSsh1Engine();
desEngine.Init(true, new KeyParameter(keydata));
BufferedBlockCipher bufferedBlockCipher = new BufferedBlockCipher(desEngine);
byte[] ouputBuffer = bufferedBlockCipher.ProcessBytes(
privateKeyBuilder.GetBlobAsPinnedByteArray().Data);
builder.AddBytes(ouputBuffer);
passphrase.Dispose();
}
/* writing result to file */
var builderOutput = builder.GetBlobAsPinnedByteArray();
aStream.Write(builderOutput.Data, 0, builderOutput.Data.Length);
aStream.Close();
}
