Triple DES Encrypt C# - Decrypt in Java

Question

I\'m getting a Triple DES decrypted string from the clients server, which has been coded in c# (see below):

using System.IO;
using System;
using System.Secur         


        

Answer 1

acording https://stackoverflow.com/a/33768305/1140304 you can use unicode instead of UTF-8 in java code

encrypt in c# :

public static string Encrypt2(string clearText,string key)
{
    try
    {
        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());
        }
        return encryptedText;
    }
    catch (Exception exception)
    {
        return "";
    }
}

for decode in c# you can use:

public static string Decrypt2(string cipher,string key)
{
    try
    {
        byte[] clearBytes = Convert.FromBase64String(cipher);
        MD5 md5 = new MD5CryptoServiceProvider();
        byte[] md5Bytes = md5.ComputeHash(Encoding.Unicode.GetBytes(key));
        string encryptedText = "";
        TripleDES des = new TripleDESCryptoServiceProvider();
        des.KeySize = 128;
        des.Mode = CipherMode.CBC;
        des.Padding = PaddingMode.PKCS7;
        byte[] ivBytes = new byte[8];
        des.Key = md5Bytes;
        des.IV = ivBytes;
        ICryptoTransform ct = des.CreateDecryptor();
        byte[] resultArray = ct.TransformFinalBlock(clearBytes, 0, clearBytes.Length);
        encryptedText = Encoding.Unicode.GetString(resultArray);
        return encryptedText;
    }
    catch (Exception exception)
    {
        return "";
    }
}

now, for encrypt in java you can use :

private String _encrypt2(String clearText,String key )
{
    try
    {
        /**
         * create md5
         */
        MessageDigest md = MessageDigest.getInstance("md5");
        byte[] digestOfPassword = md.digest(key.getBytes("UTF-16LE"));
        byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24);
        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.encodeToString(cipherText,Base64.DEFAULT);
        return output;
    }
    catch (Exception ex) {}
    return "";
}

and for decrypt in java :

private String _decrypt2(String encryptText,String key)
{

    MessageDigest md = null;
    byte[] digestOfPassword = null;

    try
    {
        byte[] message = Base64.decode(encryptText.getBytes("UTF-16LE"), Base64.DEFAULT);

        /**
         * make md5
         */
        md = MessageDigest.getInstance("md5");
        digestOfPassword = md.digest(key.getBytes("UTF-16LE"));
        byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24);
        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.DECRYPT_MODE, secretKey, iv);
        byte[] cipherText = cipher.doFinal(message);

        return new String(cipherText, "UTF-16LE");
    }
    catch (NoSuchAlgorithmException e)
    {
        e.printStackTrace();
    }
    catch (UnsupportedEncodingException e)
    {
        e.printStackTrace();
    }
    catch (InvalidKeyException e)
    {
        e.printStackTrace();
    }
    catch (InvalidAlgorithmParameterException e)
    {
        e.printStackTrace();
    }
    catch (NoSuchPaddingException e)
    {
        e.printStackTrace();
    }
    catch (BadPaddingException e)
    {
        e.printStackTrace();
    }
    catch (IllegalBlockSizeException e)
    {
        e.printStackTrace();
    }
    return "";
}