Content by Cory Doctorow (top ebook reader .TXT) 📕

their keys secret, they can assume that Carol won't gain access to their cleartext messages, even though she has access to the cipher and the ciphertext. Conveniently enough, the keys are the shortest and simplest of the secrets, too: hence even easier to keep away from Carol. Hooray for Bob and Alice.

Now, let's apply this to DRM.

In DRM, the attacker is *also the recipient*. It's not Alice and Bob and Carol, it's just Alice and Bob. Alice sells Bob a DVD. She sells Bob a DVD player. The DVD has a movie on it -- say, Pirates of the Caribbean -- and it's enciphered with an algorithm called CSS -- Content Scrambling System. The DVD player has a CSS un-scrambler.

Now, let's take stock of what's a secret here: the cipher is well-known. The ciphertext is most assuredly in enemy hands, arrr. So what? As long as the key is secret from the attacker, we're golden.

But there's the rub. Alice wants Bob to buy Pirates of the Caribbean from her. Bob will only buy Pirates of the Caribbean if he can descramble the CSS-encrypted VOB -- video object -- on his DVD player. Otherwise, the disc is only useful to Bob as a drinks-coaster. So Alice has to provide Bob -- the attacker -- with the key, the cipher and the ciphertext.

Hilarity ensues.

DRM systems are usually broken in minutes, sometimes days. Rarely, months. It's not because the people who think them up are stupid. It's not because the people who break them are smart. It's not because there's a flaw in the algorithms. At the end of the day, all DRM systems share a common vulnerability: they provide their attackers with ciphertext, the cipher and the key. At this point, the secret isn't a secret anymore.

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2. DRM systems are bad for society

Raise your hand if you're thinking something like, "But DRM doesn't have to be proof against smart attackers, only average individuals! It's like a speedbump!"

Put your hand down.

This is a fallacy for two reasons: one technical, and one social. They're both bad for society, though.

Here's the technical reason: I don't need to be a cracker to break your DRM. I only need to know how to search Google, or Kazaa, or any of the other general-purpose search tools for the cleartext that someone smarter than me has extracted.

Raise your hand if you're thinking something like, "But NGSCB can solve this problem: we'll lock the secrets up on the logic board and goop it all up with epoxy."

Put your hand down.

Raise your hand if you're a co-author of the Darknet paper.

Everyone in the first group, meet the co-authors of the Darknet paper. This is a paper that says, among other things, that DRM will fail for this very reason. Put your hands down, guys.

Here's the social reason that DRM fails: keeping an honest user honest is like keeping a tall user tall. DRM vendors tell us that their technology is meant to be proof against average users, not organized criminal gangs like the Ukrainian pirates who stamp out millions of high-quality counterfeits. It's not meant to be proof against sophisticated college kids. It's not meant to be proof against anyone who knows how to edit her registry, or hold down the shift key at the right moment, or use a search engine. At the end of the day, the user DRM is meant to defend against is the most unsophisticated and least capable among us.

Here's a true story about a user I know who was stopped by DRM. She's smart, college educated, and knows nothing about electronics. She has three kids. She has a DVD in the living room and an old VHS deck in the kids' playroom. One day, she brought home the Toy Story DVD for the kids. That's a substantial investment, and given the generally jam-smeared character of everything the kids get their paws on, she decided to tape the DVD off to VHS and give that to the kids -- that way she could make a fresh VHS copy when the first one went south. She cabled her DVD into her VHS and pressed play on the DVD and record on the VCR and waited.

Before I go farther, I want us all to stop a moment and marvel at this. Here is someone who is practically technophobic, but who was able to construct a mental model of sufficient accuracy that she figured out that she could connect her cables in the right order and dub her digital disc off to analog tape. I imagine that everyone in this room is the front-line tech support for someone in her or his family: wouldn't it be great if all our non-geek friends and relatives were this clever and imaginative?

I also want to point out that this is the proverbial honest user. She's not making a copy for the next door neighbors. She's not making a copy and selling it on a blanket on Canal Street. She's not ripping it to her hard-drive, DivX encoding it and putting it in her Kazaa sharepoint. She's doing something *honest* -- moving it from one format to another. She's home taping.

Except she fails. There's a DRM system called Macrovision embedded -- by law -- in every VHS that messes with the vertical blanking interval in the signal and causes any tape made in this fashion to fail. Macrovision can be defeated for about $10 with a gadget readily available on eBay. But our infringer doesn't know that. She's "honest." Technically unsophisticated. Not stupid, mind you -- just naive.

The Darknet paper addresses this possibility: it even predicts what this person will do in the long run: she'll find out about Kazaa and the next time she wants to get a movie for the kids, she'll download it from the net and burn it for them.

In order to delay that day for as long as possible, our lawmakers and big rightsholder interests have come up with a disastrous policy called anticircumvention.

Here's how anticircumvention works: if you put a lock -- an access control -- around a copyrighted work, it is illegal to break that lock. It's illegal to make a tool that breaks that lock. It's illegal to tell someone how to make that tool. One court even held it illegal to tell someone where she can find out how to make that tool.

Remember Schneier's Law? Anyone can come up with a security system so clever that he can't see its flaws. The only way to find the flaws in security is to disclose the system's workings and invite public feedback. But now we live in a world where any cipher used to fence off a copyrighted work is off-limits to that kind of feedback. That's something that a Princeton engineering prof named Ed Felten and his team discovered when he submitted a paper to an academic conference on the failings in the Secure Digital Music Initiative, a watermarking scheme proposed by the recording industry. The RIAA responded by threatening to sue his ass if he tried it. We fought them because Ed is the kind of client that impact litigators love: unimpeachable and clean-cut and the RIAA folded. Lucky Ed. Maybe the next guy isn't so lucky.

Matter of fact, the next guy wasn't. Dmitry Sklyarov is a Russian programmer who gave a talk at a hacker con in Vegas on the failings in Adobe's e-book locks. The FBI threw him in the slam for 30 days. He copped a plea, went home to Russia, and the Russian equivalent of the State Department issued a blanket warning to its researchers to stay away from American conferences, since we'd apparently turned into the kind of country where certain equations are illegal.

Anticircumvention is a powerful tool for people who want to exclude competitors. If you claim that your car engine firmware is a "copyrighted work," you can sue anyone who makes a tool for interfacing with it. That's not just bad news for mechanics -- think of the hotrodders who want to chip their cars to tweak the performance settings. We have companies like Lexmark claiming that their printer cartridges contain copyrighted works -- software that trips an "I am empty" flag when the toner runs out, and have sued a competitor who made a remanufactured cartridge that reset the flag. Even garage-door opener companies have gotten in on the act, claiming that their receivers' firmware are copyrighted works. Copyrighted cars, print carts and garage-door openers: what's next, copyrighted light-fixtures?

Even in the context of legitimate -- excuse me, "traditional" -- copyrighted works like movies on DVDs, anticircumvention is bad news. Copyright is a delicate balance. It gives creators and their assignees some rights, but it also reserves some rights to the public. For example, an author has no right to prohibit anyone from transcoding his books into assistive formats for the blind. More importantly, though, a creator has a very limited say over what you can do once you lawfully acquire her works. If I buy your book, your painting, or your DVD, it belongs to me. It's my property. Not my "intellectual property" -- a whacky kind of pseudo-property that's swiss-cheesed with exceptions, easements and limitations -- but real, no-fooling, actual tangible *property* -- the kind of thing that courts have been managing through property law for centuries.

But anticirumvention lets rightsholders invent new and exciting copyrights for themselves -- to write private laws without accountability or deliberation -- that expropriate your interest in your physical property to their favor. Region-coded DVDs are an example of this: there's no copyright here or in anywhere I know of that says that an author should be able to control where you enjoy her creative works, once you've paid for them. I can buy a book and throw it in my bag and take it anywhere from Toronto to Timbuktu, and read it wherever I am: I can even buy books in America and bring them to the UK, where the author may have an exclusive distribution deal with a local publisher who sells them for double the US shelf-price. When I'm done with it, I can sell it on or give it away in the UK. Copyright lawyers call this "First Sale," but it may be simpler to think of it as "Capitalism."

The keys to decrypt a DVD are controlled by an org called DVD-CCA, and they have a bunch of licensing requirements for anyone who gets a key from them. Among these is something called region-coding: if you buy a DVD in France, it'll have a flag set that says, "I am a European DVD." Bring that DVD to America and your DVD player will compare the flag to its list of permitted regions, and if they don't match, it will tell you that it's not allowed to play your disc.

Remember: there is no copyright that says that an author gets to do this. When we wrote the copyright statutes and granted authors the right to control display, performance, duplication, derivative works, and so forth, we didn't leave out "geography" by accident. That was on-purpose.

So when your French DVD won't play in America, that's not because it'd be illegal to do so: it's because the studios have invented a business-model and then invented a copyright law to prop it up. The DVD is your property and so is the DVD player, but if you break the region-coding on your disc, you're going