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Old 14th February 2007, 19:52   #239  |  Link
FoxDisc
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Join Date: Jan 2007
Posts: 274
Quote:
Originally Posted by brand1130x View Post
so is this processing key the "holy grail" of keys?
No. It's a key derived from a device key and other information on a disk that allows other keys to be calculated, ultimately leading to the final title key that decrypts the video data. It appears to have the advantage that every device key currently issued (these are in the players) when used with the current MKB on every disc currently issued (BuRay and HD-DVD) results in this same Processing Key, which then leads to the correct Title Key. If I understand it correctly, this Processing Key will no longer work with new disks if the new disks are provided with a new MKB.

There are currently two AACS bypass methods. One is this Processing Key, which works for all disks and comes from sniffing the USB connection, and one is the Title Key/Volume Unique Key which works for only the specific disk it was obtained from and comes from the memory dump of a player while playing that disk.

What can they do to stop future bypasses? I don't honestly know for sure, and I'd trust Arnezami's analysis, more than anything I say here, but I'll take a stab at it:

To stop the first method (described in this thread), they will have to make the Processing Key that is currently being calculated from the current device keys and MKBs not work. I think that means they have to change the MKB on new disks (this is a fairly big deal, but it's part of their designed in system). Second, they'll have to try to prevent the new Processing Key from being sniffed as this one was.

To stop the second method (title key from mem dump), they could simply have the offending software rewritten to try to make it harder to locate the title key.

I suppose they could stop allowing software players altogether, making it harder to implement either method, as hardware extraction is more difficult than hacking a PC. The battle goes on, but I'm putting my money on the people here who don't want DRM and do want to make fair use of what they buy. Either way, it's interesting to watch.
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