Carnal Reason

Towards the end of December, I recommended Peter Gutmann’s article A Cost Analysis of Windows Vista Content Protection. Recently, Gutmann was interviewed by Steve Gibson on the Security Now podcast (episode 74, also available as a transcript). Gutmann and Gibson discuss in some detail the extreme redesign of the Windows operating system undertaken to protect high definition dvd data. Interesting stuff, I highly recommend it.

But I know that many do not have the time or inclination to deal with that kind of geekery. As a service to my readers, I’m going to take a shot at explaining what has been done, and why.

The goal of Vista’s digital rights management (DRM) systems is to prevent the user from making unauthorized copies of high definition dvds (with standard dvds the cat is already out of the bag). The dvd data comes encrypted on disk. Vista must unencrypt it in order to play the dvd. The goal of the system is to keep all data streams encrypted until the last possible moment, when the data is finally displayed on the monitor. In particular, data on the system bus and on the video output jacks is still encrypted. That keeps the data safe from the evil user as long as is feasible. Hint: early adopters of high end displays may be screwed. Their displays cannot handle the encrypted data. Tough luck, that’s why it’s called the bleeding edge.

Hollywood bemoans the fact that the data must eventually be displayed in the clear when it exits the monitor (speakers in the case of audio). This unfortunate necessity is called the analog hole. Hollywood would love to plug the analog hole, and has talked of watermarked images and intelligent cameras that will not copy watermarked data, but that is all sci-fi at this time.

Most security people will tell you that this whole DRM effort is doomed to failure. Brushing aside the analog hole, professional pirates in Eastern Europe or in Asia have the technical resources and the will to eventually break these complicated and hence brittle DRM systems. So what is the point of throwing so much expensive and intrusive technology at a problem when the effort to protect dvd data from copying is doomed to failure? Are these Hollywood folk stupid?

When you think the other guy is stupid, perhaps it is time to consider whether you understand his motives.

The DRM schemes which Windows Vista exemplifies will fail at their ostensible goal of preventing unauthorized copying. But that is not their only purpose. The other purpose is to create a generation of playback devices that will only play high def content if it is locked down with very fancy encryption. It is true that high tech pirates will be able to circumvent theses schemes, but they are not the real threat. They, like shoplifters, are just part of the cost of doing business.

Consider that you, today, can make professional grade audio recordings using little more than a computer and the right software. You can do what would have taken a sound studio not too many years ago. The same thing is happening with respect to video recording. In the not so distant future, talented amateurs using consumer grade cameras and computers will be able to make professional quality movies. What they will not be able to do is encode those movies with the sort of DRM required to get those movies to display on high definition playback gear. The gear will refuse to play the movies because the in the absence of DRM, the player will either lock down or degrade the playback. The amateur movie will lack DRM because that DRM will only be licensed at very high cost to the right studios.

I submit that the small independent film makers will be cut out of the picture (so to speak) unless they make deals with big studios to protect their work with DRM, and so make it ready for distribution. And the big studios will be in control again. DRM = anti-disintermediation. Very slick.

Posted on January 15th, 2007 by pwyll
Filed under: General