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.

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!