Tor, the censorship-busting technology developed by the US Navy and promoted by the State Department as part of the solution to allowing for free communications in repressive regimes, is likely illegal technology under the Stop Online Piracy Act. SOPA makes provision for punishing Americans who contribute expertise to projects that can be used to defeat its censorship regime, and Tor fits the bill.

"I worry that it is vague enough, and the intention to prevent tunneling around court-ordered restrictions clear enough, that courts will bend over backwards to find a violation," says Mark Lemley, a professor at Stanford Law School who specializes in intellectual property law.

Smith's anti-circumvention language appears designed to target software such as MAFIAAFire, the Firefox add-on that bypassed domain seizures, and ThePirateBay Dancing and Tamer Rizk's DeSOPA add-ons, which take a similar approach. (As CNET reported in May, the U.S. Department of Homeland Security has tried, unsuccessfully so far, to remove MAFIAAFire from the Web.)

But Smith worded SOPA broadly enough that the anti-circumvention language isn't limited to Firefox add-ons. In an echo of the 1998 Digital Millennium Copyright Act's anti-circumvention section, SOPA targets anyone who "knowingly and willfully provides or offers to provide a product or service designed or marketed by such entity…for the circumvention or bypassing" of a Justice Department-erected blockade.