Comments on: Joining The AACS Fiasco http://www.gringod.com/2007/05/03/joining-the-aacs-fiasco/ Randomised nonsense. Fri, 04 Nov 2011 08:49:25 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: GrinGod [dot] Com » Blog Archive » Everybody Needs A Number http://www.gringod.com/2007/05/03/joining-the-aacs-fiasco/comment-page-1/#comment-18096 GrinGod [dot] Com » Blog Archive » Everybody Needs A Number Thu, 10 May 2007 21:30:09 +0000 http://www.gringod.com/2007/05/03/joining-the-aacs-fiasco/#comment-18096 [...] As I previously blogged, the AACS-LA has a 128bit hex number that they call their own, and nobody else can use it without their expressed permission. If anyone does use it then the AACS-LA can use the power of the DMCA to stop its use and sue the people that used it, if they so wish. What gives the AACS-LA the rights to do this is that the number is used for the encryption of data (on HD-DVD and Blueray discs). [...] [...] As I previously blogged, the AACS-LA has a 128bit hex number that they call their own, and nobody else can use it without their expressed permission. If anyone does use it then the AACS-LA can use the power of the DMCA to stop its use and sue the people that used it, if they so wish. What gives the AACS-LA the rights to do this is that the number is used for the encryption of data (on HD-DVD and Blueray discs). [...]

]]> By: Damien Guard http://www.gringod.com/2007/05/03/joining-the-aacs-fiasco/comment-page-1/#comment-17862 Damien Guard Thu, 03 May 2007 07:09:05 +0000 http://www.gringod.com/2007/05/03/joining-the-aacs-fiasco/#comment-17862 If it's anything like DVD then the content is encrypted with a 'volume' key that changes per disc. The volume key is on the disc a few hundred times, each encrypted with a 'vendor' key. The idea was that should a vendor key become compromised then they would pull it from future discs and issue the vendor with one of the new spare keys already in use on all the discs. The upshot would be that discs would continue to play everywhere except new discs would not play in compromised players. Obviously updating PowerDVD and WinDVD to use new keys is a lot easier than shipping a firmware update to thousands of set-top player owners so I'm not sure they ever revoked those keys. The problem with the DVD hack is that they broke the encryption in such a way that they uncovered *all* the vendor keys. I would imagine the situation is similar with AACS. [)amien If it’s anything like DVD then the content is encrypted with a ‘volume’ key that changes per disc. The volume key is on the disc a few hundred times, each encrypted with a ‘vendor’ key.

The idea was that should a vendor key become compromised then they would pull it from future discs and issue the vendor with one of the new spare keys already in use on all the discs.

The upshot would be that discs would continue to play everywhere except new discs would not play in compromised players. Obviously updating PowerDVD and WinDVD to use new keys is a lot easier than shipping a firmware update to thousands of set-top player owners so I’m not sure they ever revoked those keys.

The problem with the DVD hack is that they broke the encryption in such a way that they uncovered *all* the vendor keys.

I would imagine the situation is similar with AACS.

[)amien

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