An order issued Saturday by the U.S. Copyright Office of the Library of Congress will make unlocking a cell phone illegal under certain conditions. 

An amendment to the Digital Millennium Copyright Act will apply to all cell phones purchased after Saturday and is aimed less at individual subscribers who buy their phones at subsidized rates, but rather at stemming what CTIA alleges is large-scale phone trafficking operations that buy large quantities of prepaid phones, unlock them, and resell them in foreign markets where carriers do not subsidize handsets. 

Still, even if implemented against trafficking operations, the new rules open up the door for penalties against individuals who unlock their devices. 

Persons who unlock their devices are now subject to $2,500 fines, while larger operations could be fined as much as $500,000 and imprisoned for 5 years, according to Public Knowledge. 

The new rules overturn a ruling from June of 2010, when the Library of Congress said cell phone users who unlock their phones are not in violation of the Digital Millennium Copyright Act (DMCA).

That ruling stemmed from a request from the Electronic Frontier Foundation (EFF) that asked the Librarian of Congress to renew a 2006 rule exempting cell phone unlocking so handsets can be used with other telecom carriers. At the time, the EFF said cell phone unlockers had been successfully sued under the DMCA even though there was no copyright infringement involved in the unlocking.

Sherwin Siy, of consumer advocacy group Public Knowledge, says there's a lot of problems with this most recent ruling. 

"It's a little ridiculous to think that copyright laws are intended to prevent people from switching between different phone providers easily," Siy wrote in a blog. "Instead of being used to reward authors and creators (it's not like the phone firmware is a big cash cow for anyone), it's being used to lock customers in to their existing providers, hurting their ability to vote with their feet and switch to a competitor."