Locked settings prevent users from accessing about:config and changing the security settings set by the system administrator. Locked settings should be placed in the mozilla.cfg file. The mozilla.cfg file is an encoded file of JavaScript commands. The encoding is a simple "byte-shifting" with an offset of 13 (Netscape 4 used a similar encoding, but with a 7 instead). This file also needs to be "called" from the configuration file local-settings.js