Free WordPress Copyright Proof pluginFree
A copyright notice with teeth! Prove ownership, protect your copyright, and copy protect. Obtain a digitally signed and time-stamped certificate of content of each wordpress post (for proof of copyright). Inserts combined certification, copyright, licensing, and attribution notice at end of post. At your option, your post’s url will be shown on digiprove.com (will be a hyperlink for Digiprove subscribers) to your post. Optional anti-theft feature to copy protect your content, and will record ip addresses of attempted thieves. Supports multiple users.
Source from: WordPress.org