Extension:ROT13

The ROT13 extension is probably the most trivially-bypassed security measure known to man. It displays content as ROT13-encrypted, but anyone who clicks "Edit" or uses prop=revisions will be able to view the plaintext. The only purpose this extension serves is to (hopefully) prevent content from being easily found via keyword-reliant search engines or read by users who are so wiki-naive as to not know about the edit screen or the API. Sadly, this is probably about 95 percent of the Internet-using population.

$wgROT13Right
Set $wgROT13Right to, say, 'block' if you want the __ROT13__ to render the page as ROT13 for anyone without the block right. It defaults to 'block' anyway. For whatever reason, it doesn't seem to want to work if you put the __ROT13__ right at the beginning of the page, so try elsewhere.

Usage
Suppose you want only users with the  right (aka sysops; see Manual:User rights) to be able to read your document. Use the following:

The result, for those users who don't have the  right, will be: ZrqvnJvxv vf njrfbzr!

You can also use __ROT13__ to render the contents of the whole page as ROT13 to those who lack the right specified in $wgROT13Right ('block' by default).