encreyption less 8

@@ -10,12 +10,16 @@ class Encryption {
     //密钥
     private static $_secrect_key = 'yoho9646abcdefgh';
 
+    //前面补8位0
+    private static $_preString = '00000000';
+
     /**
      * 加密方法
      * @param string $str
      * @return string
      */
     public static function encrypt($str){
+        $str = self::$_preString.$str;
         //AES, 128 ECB模式加密数据
         $screct_key = self::$_secrect_key;
         $str = trim($str);
@@ -38,6 +42,7 @@ class Encryption {
         $encrypt_str =  mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $screct_key, $str, MCRYPT_MODE_ECB, $iv);
         $encrypt_str = trim($encrypt_str);
         $encrypt_str = self::stripPKSC7Padding($encrypt_str);
+        $encrypt_str = ltrim($encrypt_str, self::$_preString);
         return $encrypt_str;
 
     }