Interesting People mailing list archives
AACS: A Tale of Three Keys
From: David Farber <dave () farber net>
Date: Sat, 17 Feb 2007 12:14:25 -0500
Begin forwarded message: From: Monty Solomon <monty () roscom com> Date: February 17, 2007 11:35:21 AM EST To: undisclosed-recipient:; Subject: AACS: A Tale of Three Keys AACS: A Tale of Three Keys Thursday February 15, 2007 by J. Alex Halderman This week brings further developments in the gradual meltdown of AACS (the encryption scheme used for HD-DVD and Blu-Ray discs). Last Sunday, a member of the Doom9 forum, writing under the pseudonym Arnezami, managed to extract a "processing key" from an HD-DVD player application. Arnezami says that this processing key can be used to decrypt all existing HD-DVD and Blu-Ray discs. Though currently this attack is more powerful than previous breaks, which focused on a different kind of key, its usefulness will probably diminish as AACS implementers adapt. To explain what's at stake, we need to describe a few more details about the way AACS manages keys. Recall that AACS player applications and devices are assigned secret device keys. Devices can use these keys to calculate a much larger set of keys called processing keys. Each AACS movie is encrypted with a unique title key, and several copies of the title key, encrypted with different processing keys, are stored on the disc. To play a disc, a device figures out which of the encrypted title keys it has the ability to decrypt. Then it uses its device keys to compute the necessary processing key, uses the processing key to decrypt the title key, and uses the title key to extract the content. ... http://www.freedom-to-tinker.com/?p=1121 ------------------------------------------- Archives: http://v2.listbox.com/member/archive/247/@now Powered by Listbox: http://www.listbox.com
Current thread:
- AACS: A Tale of Three Keys David Farber (Feb 17)