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Archives for 2005

DMCA, and Disrupting the Darknet

August 17, 2005 by

Fred von Lohmann’s paper argues that the DMCA has failed to keep infringing copies of copyrighted works from reaching the masses. Fred argues that the DMCA has not prevented “protected” files from being ripped, and that once those files are ripped they appear on the darknet where they are available to everyone. I think Fred is right that the DMCA and the DRM (anti-copying) technologies it supports have failed utterly to keep material off the darknet.

Over at the Picker MobBlog, several people have suggested an alternate rationale for the DMCA: that it might help raise the cost and difficulty of using the darknet. The argument is that even if the DMCA doesn’t help keep content from reaching the darknet, it may help stop material on the darknet from reaching end users.

I don’t think this rationale works. Certainly, copyright owners using lawsuits and technical attacks in an attempt to disrupt the darknet. They have sued many end users and a few makers of technologies used for darknet filesharing. They have launched technical attacks including monitoring, spoofing, and perhaps even limited denial of service attacks. The disruption campaign is having a nonzero effect. But as far as I can tell, the DMCA plays no role in this campaign and does nothing to bolster it.

Why? Because nobody on the darknet is violating the DMCA. Files arrive on the darknet having already been stripped of any technical protection measures (TPMs, in the DMCA lingo). TPMs just aren’t present on the darknet. And you can’t circumvent a TPM that isn’t there.

To be sure, many darknet users break the law, and some makers of darknet technologies apparently break the law too. But they don’t break the DMCA; and indeed the legal attacks on the darknet have all been based on old-fashioned direct copyright infringement by end users, and contributory or vicarious infringement by technology makers. Even if there were no DMCA, the same legal and technical arms race would be going on, with the same results.

Though it has little if anything to do with the DMCA, the darknet technology arms race is an interesting topic in itself. In fact, I’m currently writing a paper about it, with my students Alex Halderman and Harlan Yu.

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DMCA: An Avoidable Failure

August 15, 2005 by

In his new paper, Fred von Lohmann argues that the Digital Millennium Copyright Act of 1998, when evaluated on its own terms, is a failure. Its advocates said it would prevent widespread online copyright infringement; and it has not done so.

Fred is right on target in diagnosing the DMCA’s failure to do what its advocates predicted. What Fred doesn’t say, though, is that this failure should have been utterly predictable – it should have been obvious when the DMCA was grinding through Congress that things would end up like this.

Let’s look at the three assumptions that underlie the darknet argument [quoting Fred]:

  1. Any widely distributed object will be available to some fraction of users in a form that permits copying.
  2. Users will copy objects if it is possible and interesting to do so.
  3. Users are connected by high-bandwidth channels.

When the DMCA passed in 1998, #1 was obviously true, and #3 was about to become true. #2 was the least certain; but if #2 turned out to be false then no DMCA-like law would be necessary anyway. So why didn’t people see this failure coming in advance?

The answer is that many people did, but Congress ignored them. The failure scenario Fred describes was already conventional wisdom among independent computer security experts by 1998. Within the community, conversations about the DMCA were not about whether it would work – everybody knew it wouldn’t – but about why Washington couldn’t see what seemed obvious to us.

When the Darknet paper was published in 2001, people in the community cheered. Not because the paper had much to say to the security community – the paper’s main argument had long been conventional wisdom – but because the paper made the argument in a clear and accessible way, and because, most of all, the authors worked for a big IT company.

For quite a while, employees of big IT companies had privately denigrated DRM and the DMCA, but had been unwilling to say so in public. Put a microphone in front of them and they would dodge questions, change the subject, or say what their employer’s official policy was. But catch them in the hotel bar afterward and they would tell a different story. Everybody knew that dissenting from the corporate line was a bad career move; and nobody wanted to be the first to do it.

And so the Darknet paper caused quite a stir outside the security community, catalyzing a valuable conversation, to which Fred’s paper is a valuable contribution. It’s an interesting intellectual exercise to weigh the consequences of the DMCA in an alternate universe where it actually prevents online infringement; but if we restrict ourselves to the facts on the ground, Fred has a very strong argument.

The DMCA has failed to prevent online infringement; and that failure should have been predictable. To me, the most interesting question is how our policymakers can avoid making this kind of mistake again.

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Measuring the DMCA Against the Darknet

August 12, 2005 by

Next week I’ll be participating in a group discussion of Fred von Lohmann’s new paper, “Measuring the DMCA Against the Darknet“, over at the Picker MobBlog. Other participants will include Julie Cohen, Wendy Gordon, Doug Lichtman, Jessica Litman, Bill Patry, Bill Rosenblatt, Larry Solum, Jim Speta, Rebecca Tushnet, and Tim Wu.

I’m looking forward to a lively debate. I’ll cross-post my entries here, with appropriate links back to the discussion over there.

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HD-DVD Camp Disses Blu-Ray DRM

August 11, 2005 by

Proponents of HD-DVD, one of the two competing next-gen DVD standards, have harsh words for the newly announced DRM technologies adopted by the competing Blu-Ray standard, according to a Consumer Electronics Daily article quoted by an AVS Forum commenter.

[Fox engineering head Andy] Setos confirmed BD+ [one of the newly announced Blu-Ray technologies] was based on the Self-Protecting Digital Content (SPDC) encryption developed by San Francisco’s Cryptography Research. That system, which provides “renewable security” in the event AACS is hacked, was rejected for HD DVD over concerns about playability and reliability issues (CED Aug 2 p1). BDA [the Blu-Ray group] obviously had a different conclusion, Setos said.

…

[Hitachi advisor Mark] Knox also took a shot at the BD+ version of SPDC, calling its “Virtual Machine” concept “a goldmine for hackers.” He said the Virtual Machine “must have access to critical security info, so any malicious code designed to run on this VM would also have access. In the words of one of the more high-tech guys ‘This feeble attempt to shut the one door on hackers is going to open up a lot of windows instead.’”

There’s an interesting technical issue behind this. SPDC’s designers say that most DRM schemes are weak because a fixed DRM design is built in to player devices; and once that design is broken – as it inevitably will be – the players are forever vulnerable. Rather than using a fixed DRM design, SPDC builds into the player device a small operating system. (They call it a lightweight virtual machine, but if you look at what it does it’s clearly an operating system.) Every piece of content can come with a computer program, packaged right on the disc with the content, which the operating system loads and runs when the content is loaded. These programs can also store data and software permanently on the player. (SPDC specifications aren’t available, but they have a semi-technical white paper and a partial security analysis.)

The idea is that rather than baking a single DRM scheme into the player, you can ship out a new DRM scheme whenever you ship out a disc. Different content publishers can use different DRM schemes, by shipping different programs on their discs. So, the argument goes, the system is more “renewable”.

The drawback for content publishers is that adversaries can switch from attacking the DRM to attacking the operating system. If somebody finds a security bug in the operating system (and, let’s face it, OS security bugs aren’t exactly unprecedented), they can exploit it to undermine any and all DRM, or to publish discs that break users’ players, or to cause other types of harm.

There are also risks for users. The SPDC documents talk about the programs having access to permanent storage on the player, and connecting to the Internet. This means a disc could install software that watches how you use your player, and reports that information to somebody across the Net. Other undesirable behaviors are possible too. And there’s nothing much the user can do to prevent them – content publishers, in the name of security, will try to prevent reverse engineering of their programs or the spread of information about what they do – and even the player manufacturer won’t be able to promise users that programs running on the player will be well-behaved.

Even beyond this, you have all of the usual reliability problems that arise on operating systems that store data and run code on behalf of independent software vendors. Users generally cope with such problems by learning about how the OS works and tweaking its configuration; but this strategy won’t work too well if the workings of the OS are supposed to be secret.

The HD-DVD advocates are right that SPDC (aka BD+) opens a real can of worms. Unless the SPDC/BD+ specifications are released, I for one won’t trust that the system is secure and stable enough to make anybody happy.

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Blu-Ray Tries to Out-DRM HD-DVD

August 10, 2005 by

Blu-Ray, one of the two competing next-gen DVD standards, has decided to up the ante by adopting even more fruitless anti-copying mechanism than the rival HD-DVD system. Blu-Ray will join HD-DVD in using the AACS technology (with its competition-limiting digital imprimatur). Blu-Ray will add two more technologies, called ROM-Mark and BD+.

ROM-Mark claims to put a hidden mark on all licensed discs. The mark will be detected by Blu-Ray players, which will refuse to play discs that don’t have it. But, somehow, it is supposed to be impossible for unlicensed disc makers to put marks on their discs. It’s not at all clear how this is supposed to work, but systems of this sort have always failed in the past, because it has always proved possible to make an exact copy of a licensed disc (including the mark).

BD+ will apparently allow the central Blu-Ray entity to update the anti-copying software in Blu-Ray players. This kind of updatability will inevitably add to the cost, complexity, and fragility of Blu-Ray players. Trying to do this raises some nasty technical issues that may not be solvable. I would like to find out more about how they think they can make this happen, especially for (say) cheap, portable players. (This technology was reportedly Fox’s reason for joining the Blu-Ray camp.)

As always, content will be copied regardless of what they try to do, and the main effect of these technologies will be to make player devices more expensive and less reliable, and to limit entry to the market for the devices. My guess is that some movie studio people actually believe these technologies will stop copying; and some know the technology won’t stop copying but want the power to limit entry.

Both groups must be happy to see the Blu-Ray and HD-DVD camps competing to make the most extravagant copy-prevention promises. To law-abiding consumers, each step in this bidding war means more expensive, less capable technologies.

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