/**

     * 对用户的密码进行加密

     * @param $password

     * @param $encrypt //传入加密串，在修改密码时做认证

     * @return array/password

     */

    function password($password, $encrypt='') {

        $pwd = array();

        $pwd['encrypt'] =  $encrypt ? $encrypt : create_randomstr();

        $pwd['password'] = md5(md5(trim($password)).$pwd['encrypt']);

        return $encrypt ? $pwd['password'] : $pwd;

    }

    /**

     * 生成随机字符串

     * @param string $lenth 长度

     * @return string 字符串

     */

    function create_randomstr($lenth = 6) {

        return random($lenth, '123456789abcdefghijklmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ');

    }