I have a problem decrypting an encrypted string that was encrypted in Java using the DES algorithm. I think my main problem is, that I don't see any salt or IV specifications in the java code.
I have following information: This HexSequence is the encrypted data I have to decrypt: 9465E19A6B9060D75C3F7256ED1F4D21EDC18BB185304B92061308A32725BE760F1847E3B19C1D3548F61165EA2E785E48F61165EA2E78
Algorithm: DES, Padding: DES/ECB/NoPadding, Key: TESTKEY123
After decryption I should get: 550000000018h000000273Al2011112214340600000000000000000000000000
The java-code used to encrypt the data looks like this:
public class Encryptor {
private SecretKey secretKey;
private Cipher cipher;
public Encryptor(String algorithmName, String paddingName, String key) {
String keyHexCode = StringUtils.convertUnicodeToHexCode(key.getBytes());
try {
byte[] desKeyData = StringUtils.convertHexStringToByteArray(keyHexCode);
DESKeySpec desKeySpec = null;
try {
desKeySpec = new DESKeySpec(desKeyData);
} catch (InvalidKeyException e) {
e.printStackTrace();
}
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(algorithmName);
try {
secretKey = keyFactory.generateSecret(desKeySpec);
} catch (InvalidKeySpecException e) {
e.printStackTrace();
}
try {
cipher = Cipher.getInstance(paddingName);
} catch (NoSuchPaddingException e) {
// TODO: handle exception
}
} catch (NoSuchAlgorithmException e) {
// TODO: handle exception
}
}
private void initEncryptor(int mode) {
try {
cipher.init(mode, secretKey);
} catch (InvalidKeyException e) {
// TODO: handle exception
}
}
public String encrypt(String clearText) {
initEncryptor(Cipher.ENCRYPT_MODE);
try {
// Encrypt the cleartext
byte[] encryptedBytes = cipher.doFinal(clearText.getBytes());
return StringUtils.convertUnicodeToHexCode(encryptedBytes).toUpperCase();
} catch (IllegalBlockSizeException e) {
// TODO: handle exception
} catch (BadPaddingException e) {
// TODO: handle exception
}
return "";
}
public String decrypt(String encryptedTextHex) {
byte[] encryptedText = StringUtils.convertHexCodeSequenceToUnicode(encryptedTextHex);
initEncryptor(Cipher.DECRYPT_MODE);
try {
// Decrypt the encryptedTextHex
return new String(cipher.doFinal(encryptedText));
} catch (IllegalBlockSizeException e) {
// TODO: handle exception
} catch (BadPaddingException e) {
// TODO: handle exception
}
return "";
}
}
I tried to use following .net-code to decrypt the data:
public class URLDecryptor
{
public static string GetValue(string Data)
{
DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
byte[] bytes = System.Text.UnicodeEncoding.Unicode.GetBytes("TESTKEY123");
byte[] salt = new byte[8];
byte[] iv = new byte[8];
Rfc2898DeriveBytes password = new Rfc2898DeriveBytes("TESTKEY123", salt);
cryptoProvider.Key = password.GetBytes(8);
cryptoProvider.IV = iv;
cryptoProvider.Padding = PaddingMode.None;
cryptoProvider.Mode = CipherMode.ECB;
MemoryStream memStream = new MemoryStream(convertHexCodeSequenceToUnicode(Data));
CryptoStream cryptoStream = new CryptoStream(memStream, cryptoProvider.CreateDecryptor(cryptoProvider.Key, cryptoProvider.IV), CryptoStreamMode.Read);
StreamReader reader = new StreamReader(cryptoStream);
string value = reader.ReadToEnd;
reader.Close();
cryptoStream.Close();
return value;
}
private static byte[] convertHexCodeSequenceToUnicode(string hexCodeSequence)
{
byte[] bytes = new byte[(hexCodeSequence.Length / 2) + 1]; //This is strange
int index = 0;
int count = 0;
while (count < hexCodeSequence.Length) {
string hexCode = hexCodeSequence.Substring(count, 2);
bytes[index] = getHexValue(hexCode);
count += 2;
index += 1;
}
return bytes;
}
public static byte getHexValue(string hexCode)
{
return byte.Parse(hexCode, System.Globalization.NumberStyles.HexNumber);
}
}
What's strange is that line:
byte[] bytes = new byte[(hexCodeSequence.Length / 2) + 1];
The data is 55 bytes long but I have to put it in 56 bytes. It appends a 0-byte to the and of the array, but if I don't do this the cryptostream throws an error that the data to decrypt is too short.
If I try it this way I only get garbage as output. I'm using a empty salt and IV because I can't see which salt and IV the java code is using. Are there any default values I don't know?
EDIT: Java code to get the byte out of the hexCode:
private static byte getNegativeValueForHexConversion(String hexCode) {
int i = Integer.parseInt(hexCode, 16);
return (byte) (i > 127 ? i - 256 : i);
}
Looks like Java uses a signed byte and .Net uses an unsigned byte for all its functions. Is this maybe the problem?