Congress could resume debate on SOPA as early as Jan. 17, and the Senate could vote on the measure as early as Jan. 24. SOPA would block access to sites accused of violating U.S. copyright laws. The measure has been called Draconian by opponents who say it would fundamentally change the free-flow of information across the Internet. Proponents, ranging from the NBA to Universal, say the measure is needed to block sites which flagrantly flaunt copyright laws and make content available for free without paying copyright owners.

"Boycott? Nasty letter time? You decide," Andy Baird and Tony Webster, the extension's creators, wrote on the extension Web site.

Hackers have already been working on other fixes to use if the law passes, including a satellite network and a Firefox add-on that directs the browser directly to a blocked site's IP address. Such extensions are being created in part to show the regulations, if passed, will be ineffective in stopping traffic to blacklisted sites.