C# to Java TripleDES , different results

Question

I\'m attempting to convert this C# encryption algorithm to Java; however, I keep retrieving slightly different encrypted results (haven\'t tried decryption yet). It may also be

Answer 1

You are missing two things. You are using a 16 length key on the c# side since it is not padded like the Java version. By default if the key is 16 bytes in length it will be padded with the first 8 bytes of the key.

To make this match on the Java side you will have to uncomment that line that adds the padding to the key:

for (int j = 0, k = 16; j < 8;) {
  keyBytes[k++] = keyBytes[j++];
}

SecretKey secretKey = new SecretKeySpec(keyBytes, 0, 24, "DESede");

Also, on the java side there was a suggestion to make sure to use UTF-LE for the text. Make sure to use it for everything. So the lines:

byte[] digestOfPassword = md.digest(key.getBytes("UTF-16LE"));

byte[] plainTextBytes = clearText.getBytes("UTF-16LE");

In general I would make sure to set the c# params of all the tripledes object, and not depend on defaults.

Here are two versions that match in c# and java

Java

String key = "012345678901234567890123";
String clearText = "test";

MessageDigest md = MessageDigest.getInstance("md5");
byte[] digestOfPassword = md.digest(key.getBytes("UTF-16LE"));

byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24);
String byteText = Arrays.toString(keyBytes);

for (int j = 0, k = 16; j < 8;) {
  keyBytes[k++] = keyBytes[j++];
}

SecretKey secretKey = new SecretKeySpec(keyBytes, 0, 24, "DESede");

IvParameterSpec iv = new IvParameterSpec(new byte[8]);
Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");

cipher.init(Cipher.ENCRYPT_MODE, secretKey, iv);

byte[] plainTextBytes = clearText.getBytes("UTF-16LE");
byte[] cipherText = cipher.doFinal(plainTextBytes);

String output = Base64.encode(cipherText);

c#

string clearText = "test";
string key = "012345678901234567890123";
string encryptedText = "";

MD5 md5 = new MD5CryptoServiceProvider();
TripleDES des = new TripleDESCryptoServiceProvider();
des.KeySize = 128;
des.Mode = CipherMode.CBC;
des.Padding = PaddingMode.PKCS7;

byte[] md5Bytes = md5.ComputeHash(Encoding.Unicode.GetBytes(key));

byte[] ivBytes = new byte[8];


des.Key = md5Bytes;

des.IV = ivBytes;

byte[] clearBytes = Encoding.Unicode.GetBytes(clearText);

ICryptoTransform ct = des.CreateEncryptor();
using (MemoryStream ms = new MemoryStream())
{
    using (CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write))
    {
        cs.Write(clearBytes, 0, clearBytes.Length);
        cs.Close();
    }
    encryptedText = Convert.ToBase64String(ms.ToArray());
}

Edited: Both versions now return the test case result "nmj8MjjO52y928Syqf0J+g=="