Today I had a remarkable conversation with an anonymous tipster who had a fascinating story to tell about the latest AACS key leak:
The world became a little more magical yesterday with the publication of a new "processing key" that can be used to unlock the AACS copy protection on the latest round of HD-DVD movies. This event is remarkable not only for its timing–barely a week after the release of the discs that the key was intended to secure–but also for the clever way in which the key first appeared on the net. Though this second part of the story hasn't received much attention, it deserves to go down in the annals of hacker lore.
The previous processing key, 09 F9 …, began circulating in February being discovered by a hacker named arnezami. With this 128-bit number, anyone could strip the encryption from every HD-DVD title on the market. The key was reposted on thousands of sites, and quickly made it to the front page of Digg. When Digg tried to censor the key in response to DMCA threats from the AACS authorities, users staged a revolt, reposting it in hundreds of creative ways. The movie studios switched to technological countermeasures, and, starting last week, all new HD-DVD titles were modified so that the key couldn't decrypt them. Hackers began furiously searching for a new key.
In the mean time, Ed Felten of Freedom-to-Tinker satirized the idea that someone could have legal rights to a number. He wrote a blog post, "You Can Own an Integer Too," that gives each reader his or her very own randomly generated 128-bit integer. Hundreds proudly posted their shiny new integers in the comments, some humorously threatening legal action against anyone who would copy them:
5D 4A F0 D9 58 04 3B 06 C8 B2 59 85 A1 5D 6A 88
For the record!! This ones mine. You can look but don't touch.
B8 5C 6D 1E 07 F9 AB 5E 0F 0D 48 A5 3B 1F 6B C7
use it and ill sue! be prepared!
Blending in with the rest was this innocuous looking message from a user named BtCB:
45 5F E1 04 22 CA 29 C4 93 3F 95 05 2B 79 2A B2
What are the odds that this is the new processing key?
(Hint for arnezami: uv=00000047)
Of course, the odds are basically zero if the number was chosen at random. You have a better chance of winning the Powerball jackpot four days in a row. So, for more than a week, everyone who read the comment assumed that it was just another joke. But one thing about it was different: the cryptic hint to arnezami, a "uv" number, a pointer to a specific key within the AACS keyspace.
You can probably guess the rest of the story. Eventually someone tipped off arnezami about the strange comment, and he tried using the 45 5F … number to decrypt the new discs. It worked! It really is the new processing key. As a result, all HD-DVDs are open to the public again, at least until new titles can be updated once more.
The next move belongs to the AACS authorities. They're smart enough to know that they can't take the food coloring out of the pool. So will they send out another round of cease-and-desist letters, possibly sparking another revolt, or will they graciously admit defeat for now?