Carrier unlocking a smartphone is now illegal in the US under a new law passed in October 2012 by the Librarian of Congress and going in effect today. 

The Digital Millennium Copyright Act (DMCA) prohibits a customer from taking a smartphone from one carrier to another without explicit permission from said the original carrier. 

Customers often find themselves unlocking a smartphone when frequently travelling the globe to access the same wireless standard from a carrier in a different country, avoiding expensive roaming charges. 

The new policy does not apply to smartphones purchased before 26 January 2012, but smartphones bought after that date will most likely have to pay a fee through the carrier to become unlocked. 

It’s worth noting that Verizon offers its iPhones unlocked out of the box, letting customers take them globally without any hassle. AT&T unlocks handsets that aren’t currently under contract. 

Additionally, both Apple’s iPhone and Google’s Nexus 4 are sold factory unlocked directly to customers through both companies' online stores. These unlocked devices are sold with simply no contract in-place, letting a customer take them to any carrier with supported bands. 

Even with smartphones that are offered unlocked, several are still locked down by carriers, leaving customers seeking other methods of unlocking than dealing with a carrier. 

Prominent smartphone unlocker Will Strafach of Chronic Unlocks has noted on Twitter that unlocks will still be possible without the carrier's permission, but “the issue is that it makes it harder for the people who provide the unlocks by creating legal issues”. Before the law went into effect, Strafach held a huge sale for customers to unlock the iPhone cheaper than usual.

In protest, several people have taken to the web, starting a petition requesting the White House to rescind the DMCA law. Of the 100,000 signatures needed by 23 February 2013, 8,818 have signed the petition saying: “We ask that the White House ask the Librarian of Congress to rescind this decision, and failing that, champion a bill that makes unlocking permanently legal.”

The carriers' thinking on this is that they don’t want customers buying handsets on subsidy to ditch for another carrier. 

Of course, the DMCA law doesn’t make rooting or unlocking the bootloader of your handset illegal by any means. This law is more about the carriers. 

What do you think? Does this law affect you?