Kyle Wiens, writing at Wired:

Manufacturers have every legal right to put a password or an encryption over the tECU. Owners, on the other hand, don’t have the legal right to break the digital lock over their own equipment. The Digital Millennium Copyright Act—a 1998 copyright law designed to prevent digital piracy—classifies breaking a technological protection measure over a device’s programming as a breach of copyright. So, it’s entirely possible that changing the engine timing on his own tractor makes a farmer a criminal.

It’s not just “entirely possible,” if he’s circumventing “a technological measure that effectively controls access to a work protected under” copyright law¹, he’s committing a crime.

And those folks trading information or even hardware meant to help one another get around the manufacturers’ security measures, they’re criminals, too. The law says:

No person shall manufacture, import, offer to the public, provide, or otherwise traffic in any technology, product, service, device, component, or part thereof, that [enables or encourages its use in circumvention].²

The DMCA’s anti-circumvention provisions were poorly drafted, are overbroad, and reflect a lack of understanding by Congress of the specific problems caused by digital copyright infringement and more appropriate solutions. If you’re interested in learning more about the problems caused by the DMCA, the Electronic Frontier Foundation has done some great work toward reforming, if not the DMCA itself (yet), its interpretation and implementation.