Aes CBC加密

 <?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");
     }
 }