ProCon Latte is an add-on for the Firefox web browser that can block access to all websites except those that are listed in the whitelist. While the add-on provides access to many additional features like word based filters this article concentrates on using it to block all websites except whitelisted ones. The options of the add-on contain a form that can be filled with whitelisted urls. It is also possible to import a list of urls that should be added to the whitelist or right-click the current page and select the option to whitelist it.

It would not be a very good protection if anyone would be able to add new pages to the whitelist. This is where the password protection of the application comes into play. Once password protected only authorized users – those that enter the password correctly – can make changes to the add-on’s options. Several options are available to increase the security further by hiding the extension from the tools menu and status bar, preventing it from being disabled or uninstalled and by locking about:config so that it cannot be accessed.

Only two settings have to be changed in the options to add the security. The user has to check the Block All Traffic option in the Main Filter tab which will block all but whitelisted traffic. Then the whitelist has to be enabled by checking the Enable Whitelist box in the Whitelist tab. This is also the location to add new sites to the whitelist. Lastly the password has to be added by clicking on the Set Password button in the General tab.

Parents are probably best of to fill the whitelist together with their children by asking them about the pages that they like to view and telling them that they need to ask the parents if they cannot access a page so that the page can be enabled if appropriate.

A small notification bar will appear on top of pages that are not in the whitelist. Users with the password can override the limitation by entering the password to continue.

Is the application fool proof? Smart children might try and delete it from the user profile directory or edit the preferences so that the extension would not get loaded anymore. That’s however easily noticeable and only possible if access to the system itself is not restricted. Other possibility include booting into a live CD or using another web browser that is installed on the system.