<?php

 namespace app\components;

 use yii;

 class Aes

 {

     /**

      * This was AES-128 / CBC / PKCS5Padding

      * return base64_encode string

      * @param string $plaintext

      * @param string $key

      * @return string

      */

     public static function AesEncrypt($plaintext,$key = null)

     {

         $plaintext = trim($plaintext);

         if ($plaintext == '') return '';

         $size = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);

         //PKCS5Padding

         $padding = $size - strlen($plaintext) % $size;

         // 添加Padding

         $plaintext .= str_repeat(chr($padding), $padding);

         $module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');

         $key=self::substr($key, 0, mcrypt_enc_get_key_size($module));

         $iv = $key;

         // str_repeat($key, $size);

         /* Intialize encryption */

         mcrypt_generic_init($module, $key, $iv);

         /* Encrypt data */

         $encrypted = mcrypt_generic($module, $plaintext);

         /* Terminate encryption handler */

         mcrypt_generic_deinit($module);

         mcrypt_module_close($module);

         return base64_encode($encrypted);

     }

     /**

      * Returns the length of the given string.

      * If available uses the multibyte string function mb_strlen.

      * @param string $string the string being measured for length

      * @return integer the length of the string

      */

     private static function strlen($string)

     {

         return extension_loaded('mbstring') ? mb_strlen($string,'8bit') : strlen($string);

     }

     /**

      * Returns the portion of string specified by the start and length parameters.

      * If available uses the multibyte string function mb_substr

      * @param string $string the input string. Must be one character or longer.

      * @param integer $start the starting position

      * @param integer $length the desired portion length

      * @return string the extracted part of string, or FALSE on failure or an empty string.

      */

     private static function substr($string,$start,$length)

     {

         return extension_loaded('mbstring') ? mb_substr($string,$start,$length,'8bit') : substr($string,$start,$length);

     }

     /**

      * This was AES-128 / CBC / PKCS5Padding

      * @param string $encrypted     base64_encode encrypted string

      * @param string $key

      * @throws CException

      * @return string

      */

     public static function AesDecrypt($encrypted, $key = null)

     {

         if ($encrypted == '') return '';

         $ciphertext_dec = base64_decode($encrypted);

         $module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');

         $key=self::substr($key, 0, mcrypt_enc_get_key_size($module));

         $iv = $key;

         // str_repeat($key, 16);    //解密的初始化向量要和加密时一样。

         /* Initialize encryption module for decryption */

         mcrypt_generic_init($module, $key, $iv);

         /* Decrypt encrypted string */

         $decrypted = mdecrypt_generic($module, $ciphertext_dec);

         /* Terminate decryption handle and close module */

         mcrypt_generic_deinit($module);

         mcrypt_module_close($module);

         // echo $decrypted;die;

         //$a = rtrim($decrypted,"\0");

         return rtrim($decrypted,"\0");

     }

 }