i found a question where the answer from Elephantik basically answerd my question: DES Initialization Vector in C#
I have a file which was encrypted with the DES.EXE command line tool. And i can decrypt it with following command: "des -D -k YSTxyHBH file.cr file.txt"
With this command i get an decrypted file.txt, but i need do decrypt this file in Java.
So i tried to transfer the solution from Elephantik to Java, but there has to be something wrong with my solution, because as result i only get some encrypted text when i call the decryptData(...) method.
public byte[] decryptData(byte input[], String password) throws Exception {
byte[] result = null;
//Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
Cipher cipher = Cipher.getInstance("DES/CBC/NoPadding");
//byte[] iv = { 0, 0, 0, 0, 0, 0, 0, 0 };
byte[] iv = { -128, -128, -128, -128, -128, -128, -128, -128 };
IvParameterSpec ivspec = new IvParameterSpec(iv);
cipher.init(Cipher.DECRYPT_MODE, generateSecretKey(passwordToKey(password)), ivspec);
result = cipher.doFinal(input);
return result;
}
protected SecretKey generateSecretKey(byte[] key) throws Exception {
SecretKeyFactory factory = SecretKeyFactory.getInstance("DES");
KeySpec keySpec = new DESKeySpec(key);
SecretKey secretKey = factory.generateSecret(keySpec);
return secretKey;
}
public byte[] passwordToKey(String password) throws Exception
{
if (password == null)
throw new IllegalArgumentException("password");
if (password == "")
throw new IllegalArgumentException("password");
byte[] key = new byte[8];
for (int i = 0; i < password.length(); i++)
{
int c = (int)password.charAt(i);
if ((i % 16) < 8)
{
key[i % 8] ^= (byte)(c << 1);
}
else
{
// reverse bits e.g. 11010010 -> 01001011
c = (((c << 4) & 0xf0) | ((c >> 4) & 0x0f));
c = (((c << 2) & 0xcc) | ((c >> 2) & 0x33));
c = (((c << 1) & 0xaa) | ((c >> 1) & 0x55));
key[7 - (i % 8)] ^= (byte)c;
}
}
addOddParity(key);
byte[] target = new byte[8];
ByteArrayOutputStream outputStream = new ByteArrayOutputStream( );
outputStream.write(password.getBytes("US-ASCII"));
outputStream.write(new byte[8]);
byte[] temp = outputStream.toByteArray();
outputStream = new ByteArrayOutputStream( );
for (int i = 0; i < (password.length() + (8 - (password.length() % 8)) % 8); ++i) {
outputStream.write(temp[i]);
}
byte[] passwordBuffer = outputStream.toByteArray();
Cipher cipher = Cipher.getInstance("DES/CBC/NoPadding");
//byte[] iv = { 0, 0, 0, 0, 0, 0, 0, 0 };
byte[] iv = { -128, -128, -128, -128, -128, -128, -128, -128 };
IvParameterSpec ivspec = new IvParameterSpec(iv);
cipher.init(Cipher.ENCRYPT_MODE, generateSecretKey(key), ivspec);
for (int x = 0; x < passwordBuffer.length / 8; ++x)
{
cipher.update(passwordBuffer, 8 * x, 8, target, 0);
}
addOddParity(target);
return target;
}
private void addOddParity(byte[] buffer)
{
for (int i = 0; i < buffer.length; ++i)
{
buffer[i] = _oddParityTable[buffer[i] & 0xFF];
}
}
private static byte[] _oddParityTable = {
-127,-127,-126,-126,-124,-124,-121,-121,-120,-120,-117,-117,-115,-115,-114,-114,
-112,-112,-109,-109,-107,-107,-106,-106,-103,-103,-102,-102,-100,-100, -97, -97,
-96, -96, -93, -93, -91, -91, -90, -90, -87, -87, -86, -86, -84, -84, -81, -81,
-79, -79, -78, -78, -76, -76, -73, -73, -72, -72, -69, -69, -67, -67, -66, -66,
-64, -64, -61, -61, -59, -59, -58, -58, -55, -55, -54, -54, -52, -52, -49, -49,
-47, -47, -46, -46, -44, -44, -41, -41, -40, -40, -37, -37, -35, -35, -34, -34,
-31, -31, -30, -30, -28, -28, -25, -25, -24, -24, -21, -21, -19, -19, -18, -18,
-16, -16, -13, -13, -11, -11, -10, -10, -7, -7, -6, -6, -4, -4, -1, -1,
0, 0, 3, 3, 5, 5, 6, 6, 9, 9, 10, 10, 12, 12, 15, 15,
17, 17, 18, 18, 20, 20, 23, 23, 24, 24, 27, 27, 29, 29, 30, 30,
33, 33, 34, 34, 36, 36, 39, 39, 40, 40, 43, 43, 45, 45, 46, 46,
48, 48, 51, 51, 53, 53, 54, 54, 57, 57, 58, 58, 60, 60, 63, 63,
65, 65, 66, 66, 68, 68, 71, 71, 72, 72, 75, 75, 77, 77, 78, 78,
80, 80, 83, 83, 85, 85, 86, 86, 89, 89, 90, 90, 92, 92, 95, 95,
96, 96, 99, 99, 101, 101, 102, 102, 105, 105, 106, 106, 108, 108, 111, 111,
113, 113, 114, 114, 116, 116, 119, 119, 120, 120, 123, 123, 125, 125, 126, 126
};
