class STD3Des  {      private $key = "";      private $iv = "";      /**      * 构造，传递二个已经进行base64_encode的KEY与IV      *      * @param string $key      * @param string $iv      */      function __construct ($key, $iv)      {          if (empty($key) || empty($iv)) {              echo 'key and iv is not valid';              exit();          }          $this->key = $key;          $this->iv = $iv;      }      /**      *加密      * @param <type> $value      * @return <type>      */      public function encrypt ($value)      {          $td = mcrypt_module_open(MCRYPT_3DES, '', MCRYPT_MODE_CBC, '');          $iv = base64_decode($this->iv);          $value = $this->PaddingPKCS7($value);          $key = base64_decode($this->key);          mcrypt_generic_init($td, $key, $iv);          $ret = base64_encode(mcrypt_generic($td, $value));          mcrypt_generic_deinit($td);          mcrypt_module_close($td);          return $ret;      }      /**      *解密      * @param <type> $value      * @return <type>      */      public function decrypt ($value)      {          $td = mcrypt_module_open(MCRYPT_3DES, '', MCRYPT_MODE_CBC, '');          $iv = base64_decode($this->iv);          $key = base64_decode($this->key);          mcrypt_generic_init($td, $key, $iv);          $ret = trim(mdecrypt_generic($td, base64_decode($value)));          $ret = $this->UnPaddingPKCS7($ret);          mcrypt_generic_deinit($td);          mcrypt_module_close($td);          return $ret;      }      private function PaddingPKCS7 ($data)      {          $block_size = mcrypt_get_block_size('tripledes', 'cbc');          $padding_char = $block_size - (strlen($data) % $block_size);          $data .= str_repeat(chr($padding_char), $padding_char);          return $data;      }      private function UnPaddingPKCS7($text)      {          $pad = ord($text{strlen($text) - 1});          if ($pad > strlen($text)) {              return false;          }          if (strspn($text, chr($pad), strlen($text) - $pad) != $pad) {              return false;          }          return substr($text, 0, - 1 * $pad);      }  }    //使用  include('STD3Des.class.php');  $key='abcdefgh';  $iv='abcdefgh';  $msg='test string';  $des=new STD3Des(base64_encode($key),base64_encode($iv));  $rs1=$des->encrypt($msg);  echo $rs1.'<br />';  $rs2=$des->decrypt($rs1);  echo $rs2;

sealed public class CryptoHelper  {      /// <summary>      /// Encrypts the specified input.      /// </summary>      /// <param name="input">The input.</param>      /// <param name="key">key</param>      /// <param name="iv">iv</param>      /// <returns></returns>      public static string EncryptDes(string input, byte[] key, byte[] iv)      {          if (input == null || input.Length == 0)              return String.Empty;          DESCryptoServiceProvider des = new DESCryptoServiceProvider();          MemoryStream ms = null;          CryptoStream encStream = null;          StreamWriter sw = null;          string result = String.Empty;          try          {              ms = new MemoryStream();              // Create a CryptoStream using the memory stream and the              // CSP DES key.               //des.Mode = CipherMode.CBC;              //des.Padding = PaddingMode.PKCS7;               encStream = new CryptoStream(ms, des.CreateEncryptor(key, iv), CryptoStreamMode.Write);              // Create a StreamWriter to write a string              // to the stream.              sw = new StreamWriter(encStream);              // Write the plaintext to the stream.              sw.Write(input);              sw.Flush();              encStream.FlushFinalBlock();              ms.Flush();                result = Convert.ToBase64String(ms.GetBuffer(), 0, Convert.ToInt32(ms.Length, CultureInfo.InvariantCulture));          }          finally          {              //close objects              if (sw != null)                  sw.Close();              if (encStream != null)                  encStream.Close();              if (ms != null)                  ms.Close();          }          // Return the encrypted string          return result;      }      /// <summary>      /// Decrypts the specified input.      /// </summary>      /// <param name="input">the input.</param>      /// <param name="key">key</param>      /// <param name="iv">iv</param>      /// <returns></returns>      public static string DecryptDes(string input, byte[] key, byte[] iv)      {          byte[] buffer;          try { buffer = Convert.FromBase64String(input); }          catch (System.ArgumentNullException) { return String.Empty; }          // length is zero, or not an even multiple of four (plus a few other cases)          catch (System.FormatException) { return String.Empty; }          DESCryptoServiceProvider des = new DESCryptoServiceProvider();          MemoryStream ms = null;          CryptoStream encStream = null;          StreamReader sr = null;          string result = String.Empty;          try          {              ms = new MemoryStream(buffer);              // Create a CryptoStream using the memory stream and the              // CSP DES key.              encStream = new CryptoStream(ms, des.CreateDecryptor(key, iv), CryptoStreamMode.Read);              // Create a StreamReader for reading the stream.              sr = new StreamReader(encStream);              // Read the stream as a string.              result = sr.ReadToEnd();          }          finally          {              //close objects              if (sr != null)                  sr.Close();              if (encStream != null)                  encStream.Close();              if (ms != null)                  ms.Close();          }          return result;      }  }    //调用  string key = "abcdefgh";  string iv = "abcdefgh";  string msg="test string";  string rs1 = CryptoHelper.EncryptDes(msg, System.Text.Encoding.ASCII.GetBytes(key), System.Text.Encoding.ASCII.GetBytes(iv));  string rs2 = CryptoHelper.DecryptDes(rs1, System.Text.Encoding.ASCII.GetBytes(key), System.Text.Encoding.ASCII.GetBytes(iv));