public static string MD5Hash(string input)
{
   StringBuilder hash = new StringBuilder();
   MD5CryptoServiceProvider md5provider = new MD5CryptoServiceProvider();
   byte[] bytes = md5provider.ComputeHash(new UTF8Encoding().GetBytes(input));

   for (int i = 0; i < bytes.Length; i++)
   {
     hash.Append(bytes[i].ToString("x2"));
   }
   return hash.ToString();
}