DES encryption (c#) and mcrypt (php)

Question

I have a problem trying to encrypt a string in C# and also in PHP using DES (cbc) encryption. The problem I'm facing is that I'm getting different results using the different languages.

In C#:

SymmetricAlgorithm objCryptoService = (SymmetricAlgorithm)new DESCryptoServiceProvider();

MemoryStream memoryStream = new MemoryStream();

CryptoStream cryptoStream = new CryptoStream(memoryStream, objCryptoService.CreateEncryptor(StringToBytes.ConvertHex("0F26EF560F26EF56"), StringToBytes.ConvertHex("0F26EF560F26EF56")), CryptoStreamMode.Write);

StreamWriter writer = new StreamWriter(cryptoStream);

writer.Write("My Secret Text");

writer.Flush();

cryptoStream.FlushFinalBlock();

writer.Flush();

Response.Write("Encrypted=" + Convert.ToBase64String(memoryStream.GetBuffer(), 0, (int)memoryStream.Length));
 
Public static class StringToBytes

{

    public static byte[] ConvertHex(String sHexString)

    {

        int iCharCount = sHexString.Length;

        byte[] oBytes = new byte[iCharCount / 2];

        for (int i = 0; i < iCharCount; i += 2)

        {

            oBytes[i / 2] = Convert.ToByte(sHexString.Substring(i, 2), 16);

        }
 
        return oBytes;

    }

}

Results

 Encrypted=HLp51qoFW0ojU8eGEGkk4w==

In PHP:

$td = mcrypt_module_open('des', '', 'cbc', '');

mcrypt_generic_init($td, pack("H*", '0F26EF560F26EF56'), pack("H*", '0F26EF560F26EF56'));

$encryptedText = base64_encode(mcrypt_generic($td, 'My Secret Text'));

echo "Encrypted=".$encryptedText;

Results

 Encrypted=HLp51qoFW0rimOTafCVTVQ==

You can see that they are close...

PHP: HLp51qoFW0rimOTafCVTVQ==
C# : HLp51qoFW0ojU8eGEGkk4w==

But something is going wrong somewhere, I suspect it's a difference between (PHP) pack("H*", '0F26EF560F26EF56') and (C#) StringToBytes.ConvertHex("0F26EF560F26EF56") but I'm really struggling to spot it.

Any help would be greatly appreciated!!

Ananth G · Answer

Encryption Sometimes we want to encrypt the values that time we use MD5 Encryption and Decryption Here i give the code for Encryption and Decryption. passPhrase saltValue initVector this variables are the key for Encryption and Decryption public static string passPhrase = YOUR KEY1; public static string saltValue = YOUR KE2; public static string initVector = YOUR KE3; public static string FunForEncrypt(string objText) { int keySize = 256; int passwordIterations = 03; string hashAlgorithm = MD5; byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector); byte[] saltValueBytes = Encoding.ASCII.GetBytes(saltValue); byte[] plainTextBytes = Encoding.UTF8.GetBytes(objText); PasswordDeriveBytes password = new PasswordDeriveBytes ( passPhrase saltValueBytes hashAlgorithm passwordIterations ); byte[] keyBytes = password.GetBytes(keySize / 8); RijndaelManaged symmetricKey = new RijndaelManaged(); symmetricKey.Mode = CipherMode.CBC; ICryptoTransform encryptor = symmetricKey.CreateEncryptor ( keyBytes initVectorBytes ); MemoryStream memoryStream = new MemoryStream(); CryptoStream cryptoStream = new CryptoStream ( memoryStream encryptor CryptoStreamMode.Write ); cryptoStream.Write(plainTextBytes 0 plainTextBytes.Length); cryptoStream.FlushFinalBlock(); byte[] cipherTextBytes = memoryStream.ToArray(); memoryStream.Close(); cryptoStream.Close(); string cipherText = Convert.ToBase64String(cipherTextBytes); cipherText = HttpUtility.UrlEncode(cipherText); return cipherText; } Decryption : this below code used to Decrypt the text public static string FunForDecrypt(string cipherText) { string plainText = ; int keySize = 256; int passwordIterations = 03; string hashAlgorithm = MD5; try { cipherText = HttpUtility.UrlDecode(cipherText); byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector); byte[] saltValueBytes = Encoding.ASCII.GetBytes(saltValue); byte[] cipherTextBytes = Convert.FromBase64String(cipherText); PasswordDeriveBytes password = new PasswordDeriveBytes ( passPhrase saltValueBytes hashAlgorithm passwordIterations ); byte[] keyBytes = password.GetBytes(keySize / 8); RijndaelManaged symmetricKey = new RijndaelManaged(); symmetricKey.Mode = CipherMode.CBC; ICryptoTransform decryptor = symmetricKey.CreateDecryptor ( keyBytes initVectorBytes ); MemoryStream memoryStream = new MemoryStream(cipherTextBytes); CryptoStream cryptoStream = new CryptoStream ( memoryStream decryptor CryptoStreamMode.Read ); byte[] plainTextBytes = new byte[cipherTextBytes.Length]; int decryptedByteCount = cryptoStream.Read ( plainTextBytes 0 plainTextBytes.Length ); memoryStream.Close(); cryptoStream.Close(); plainText = Encoding.UTF8.GetString(plainTextBytes 0 decryptedByteCount); } catch (Exception ex) { plainText = ; } return plainText; }

Keith · Answer

I found this little gem which gave me a solution TripleDES rather than DES but works consistently on both platforms nonetheless! http://sanity-free.org/131/triple_des_between_php_and_csharp.html Hope that helps someone!