Question

I have a web service developed in c#.
It uses MD5 to generate session key.

c# :

public static string GetMD5(string pTxt)
{
    string sCTxt = "";
    byte[] aTxt;
    UnicodeEncoding oEnc = new UnicodeEncoding();
    aTxt = oEnc.GetBytes(pTxt);
    HashAlgorithm oHash = new MD5CryptoServiceProvider();
    byte[] aCTxt = oHash.ComputeHash(aTxt);
    foreach (byte b in aCTxt)
        sCTxt += String.Format("{0:X2}", b);
    return (sCTxt);
}

For several reasons, I have to make the same GetMD5 method in PHP.
Of course, the basic md5() function does not return the same hash (because of the UNICODE)

I tried to simulate the code in PHP but with no success

php:

public function HexToBytes($s) {
    return join('', array_map('chr', array_map('hexdec', str_split($s, 2))));
}

public function GetMD5($pStr) {
    $data = mb_convert_encoding($pStr, 'UTF-16LE', 'ASCII');
    $h = $this->HexToBytes(hash_hmac('md5', $data, ''));
    return (base64_encode($h));
}

Any idea why the result are not the same ?

Thanks in advance

---

**

FIXED! Thanks!

**

For those interested, here is the PHP method that matches the c# one

public function str2hex($string) {
   $hex = "";
   for ($i = 0; $i < strlen($string); $i++)
      $hex .= (strlen(dechex(ord($string[$i]))) < 2) ? "0" . dechex(ord($string[$i])) : dechex(ord($string[$i]));       
   return $hex;
}

public function GetMD5($pStr) {
   $data = mb_convert_encoding($pStr, 'UTF-16LE', 'UTF-8');
   $h = $this->str2hex(md5($data, true));
   return strtoupper($h);
}

Answer 1

I think you just overcomplicated your methods. The following alternatives worked for me:

C#:

public static string GetMD5(string text)
{
    byte[] textBytes = Encoding.UTF8.GetBytes(text);
    byte[] hash = MD5.Create().ComputeHash(textBytes);

    return Convert.ToBase64String(hash);
}

PHP:

public function GetMD5($pStr) {
    return base64_encode(
              md5(mb_convert_encoding($pStr, "UTF8", "Unicode"), true));
}