TUTOS can handle logins in different ways. The dafult is to store a (encrypted) password for every defined user in the database and to check it against a password provided via the webbrowser. To use this you can leave the option in config.php unchanged.
$tutos[authtype] = "db";
Other ways of authetifiaction are:
Authetification plugins are store in the [tutoshome]/auth subdirectory.