Non-reverse parameter md5 encryption method

/*
* 如只传进一个$pass参数，则表示加密，并返回一数组
* 数组包含一个加密常量和加密后的密文，如：
* array('pass'=>$pass,'encrypt'=>$encrypt);
* 传进两个参数则返回密文
*/
function password($pass,$encrypt=''){
    if(empty($encrypt)){
        $code = rand(100000, 999999);
        $password = array(
            'password'    => password(trim($pass),$code),
             'encrypt' => $code,
        );
    }else{
        $password = md5(md5($pass).$encrypt);
    }
    return $password;
}

The above method is written to prevent some md5 encryption from being too simple and easily cracked