The normal process for logging into ZoneMinder is via the login screen with username and password. In some circumstances it may be desirable to allow access directly to one or more pages, for instance from a third party application. If this option is enabled then adding an 'auth' parameter to any request will include a shortcut login bypassing the login screen, if not already logged in. As authentication hashes are time and, optionally, IP limited this can allow short-term access to ZoneMinder screens from other web pages etc. In order to use this the calling application will hae to generate the authentication hash itself and ensure it is valid. If you use this option you should ensure that you have modified the ZM_AUTH_HASH_SECRET to somethign unique to your system.