Secure login

I almost always need login function on all my applications.
Could you make a module for this?
Studying the secure login procedures is making my head spin.
Thanks!

hi, in my case, i build application with log-in form using a such logic

if(logged_in){
load(‘application’)
}else{
load(‘login_form’)
}

here is some code snippet in my application, build on CodeIgniter as server side back-end

class Efile extends CI_Controller
{
    function __construct()
    {
        parent::__construct();
    }
    
    function index(){
        $is_login=$_SESSION['login_auth'];
        if($is_login)
        {
            $this->_interface();
        }
        else
        {
            $this->_login_form();
        }
    }

    private function _login_form(){
        //load your login form here
    }

    private function _interface(){
        //load your application here
    }