Cory Doctorow, InformationWeek, writes on the impact of the DMCA on the Music Industry:
iTunes is protected by the anti-circumvention provisions in the 1998 Digital Millennium Copyright Act (DMCA), itself a law passed to comply with the 1996 UN World Intellectual Property Organization (WIPO) "Internet Treaties." The DMCA makes it a crime to circumvent "effective means of access control." That means that breaking the locks off a digital work is illegal, even if you're breaking the lock to accomplish a legal end.
It's otherwise legal to back up a DVD, or put a song on a home media-server, or quote an ebook in a college essay. But if you have to break through some copy-restriction technology to do this, you're breaking the law.
It doesn't even matter if you're the creator of the work the lock controls! You can't even access your own work on your own terms if you need to break a lock to do it.
The DMCA makes the kind of reverse-engineering that's commonplace in most industries illegal in copyright works. For example, in the software industry, it's legal to reverse-engineering a file-format in order to make a competing product. The reason: The government and the courts created copyright to provide an incentive to creativity, not to create opportunities to exclude competitors from the marketplace.
Reverse engineering is a common practice in most industries. You can reverse-engineer a blender and make your own blades, you can reverse-engineer a car and make your own muffler, and you can reverse-engineer a document and make a compatible reader. Apple loves to reverse-engineer -- from Keynote to TextEdit to Mail.app, Apple loves reverse-engineering its competitors' products and making its own competing products.
But the iTunes/iPod product line is off-limits to this kind of reverse-engineering. No one but Apple can authorize an iTunes/iPod competitor, and Apple's not exactly enthusiastic about such authorization --the one major effort to date was the stillborn Motorola ROKR phone, which was so crippled by ridiculous Apple-driven restrictions that it barely made a ripple as it sank to the bottom of the cesspool of failed electronics.