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1st June 2007, 15:30 | #81 | Link | |
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1st June 2007, 20:10 | #83 | Link | ||
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However i'm not sure if they will use SKs very soon, its quite some work to encode multiple angles, especially for BluRay the authoring effort seems quite high. Even today DVDs use multi angles very rarely. |
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1st June 2007, 21:34 | #84 | Link | |
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1st June 2007, 22:47 | #85 | Link | |
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If your real question is "why release the keys" then I guess that depends on how the system works. If it is possible to find and use a key without the AACS being able to find out which key it is, then it would be better for the "Masters of Keyfinding" to keeep their discoveries to themselves (or at least only circulated among the people writing the decrypting apps). If simply using a key means the AACS-LA can find out which one it must be, then not releasing it serves no purpose. Mal |
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1st June 2007, 23:32 | #86 | Link |
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One thing I was wondering was, the AACS LA will need to either reverse engineer AnyDVD to find out the key it is using, or to construct a MKB with some particiular values so that they can find out which C-value the programme uses. However, if I were writing AnyDVD, I would CRC each MKB and if it's not matching an officially released MKB then do nothing. This way there would be no way for the AACS to "probe" my software. True, there would be a need to update the decrypting programme when a new MKB is released, but then there would be a need anyway as the processing key will likely have been revoked.
Last edited by greath; 1st June 2007 at 23:34. |
1st June 2007, 23:48 | #87 | Link | |
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The point: they can create special discs on which they use the same/latest MKB version but just alter the C-values. The only thing they would have to do is to look at the decypted content (which is different according to the keys used by AnyDVD). There is no hiding here. Regards, arnezami Last edited by arnezami; 1st June 2007 at 23:52. |
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2nd June 2007, 06:44 | #91 | Link |
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SKBs are designed to specifically figure out which keys were comporomised in event of a black box attack. An example of such a black box would be a website, that allows a user to select and upload the MKBROM.AACS file from an HD-DVD disc, and produce a VUK.
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2nd June 2007, 10:07 | #92 | Link |
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In regards to when AACS LA will revoke the second Processing Key...
Perhaps AACS LA have a deal like Apple, that they are forced to fix any attack within a fixed number of weeks? I think Apple's period is 3 weeks. If Apple haven't fixed the attack, then Apple have to pay huge amount of cash to the record companys. If such deal exist, then it is not enough for AACS LA to just issue now Processing Keys. They will then be forced fix the attack. That being said, it could be, that AACS LA have been working on SK since the first attack, and this second Processing Key was just to buy some time... |
2nd June 2007, 10:28 | #93 | Link | |
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Also, if this service would accept any MKB, they could simply trace the player by trying different subset difference records. And even if you create a hash of the Subset Difference record and only allow specific versions, they could still create a fake MKB where they use a different media key for each subset difference and see which one is used to get the VUK. Correction: The last sentence is incorrect. While the AACS LA could do that, your webservice could easily detect that by verifying the media key with the verify media key record in the mkb. They could do the same however with multiple attacks, where some C values have the correct encrypted media key and some have not. Last edited by aKzenT; 2nd June 2007 at 10:37. Reason: corrected thinking error |
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2nd June 2007, 10:31 | #94 | Link | |
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BTW, I guess this means that the replicators must either get a MKB "template" from AACS and they must work out the C-values. Or, the AACS issues for each disc a MKB and gives the replicator a media key. They must have to do something for their $1,500 a disc licence fee........... Last edited by greath; 3rd June 2007 at 09:52. Reason: Corrected price |
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2nd June 2007, 23:07 | #95 | Link | |
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That involves serving notice on the player and drive manufacturers who then have 90 days before the new disks will appear. They will need to develop the upgrades/updates etc. and have them out before the disks are released. Also, replicators should also have the information before the 90 days to allow for manufacturing and distribution lead times. In theory, disks released within the 90 day limit should not have the latest data on them, and those released afterwards should. So a situation like Matrix where a set of disks has different versions should not really have arisen. Maybe there was a blunder at the replicators, or the timetabling of the procedures does not easily handle a situation where several different disks are made over a period of time, but they are released as a set. Also, the aacsla is not an independent enterprise selling services to the studios. It is a consortium of the studios, and I doubt if the same sort of commercial pressure exists that would apply to Apple. In addition to changing the keys, those players were supposedly changed to make it more difficult to glean keys, and thus "fix the attack" - but it is difficult to draw inferences. As regards the SK regime, that is primarily for tracing the source of gleaned keys and is not a layer of extra security to make key extraction significantly more difficult. It remains to be seen whether it also has that effect. One problem the LA have is that although they can determine where the keys came from, they will not necessarily know how they were extracted. That can make decision making tricky as there is little value in blacklisting a key leaked via a software player compromise, if you don't also try and plug the compromise by which it came. |
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2nd June 2007, 23:21 | #96 | Link | |
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3rd June 2007, 00:31 | #97 | Link | ||
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The 90 days notice and the above, altogether, make things far difficult to LA. |
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3rd June 2007, 00:40 | #98 | Link |
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@aKzenT
You are correct that in order to decrypt SKBs I also need SKB.AACS and SKF.AACS. My point is that if my hypothetical Black Box server v2.0 accepts MKBROM.AACS, SKB.AACS and SKF.AACS (Last two if available/applicable), and generates a VUK, and there are more then a handful of AACS licensees, then yes, in order to fingerpoint, AACS LA will probably have to start using SKBs. Currently the menthod of trying a bunch of MKBs works because there are only a handfull of keys out there. I can think of only Cyberlink, Nero and Intervideo as having the device keys that can use the MKB to generate a valid VUK, and Toshiba (on HD-DVD side) and 3 or 4 Blu-Ray vendors on the Blu-Ray side, that have the KCD style device keys. If AACS takes off, and there are 30 or 50 licensees, just brute-forcing will no-longer works, esp if my hypothetical Black Box Server does something to rate-limit the number of VUKs it will generate per "customer" per day. If you need to do 30 tries to figure out which device key I use, and I tell you that you can run the test once every 3 days.... By the time you know, I will probably be on a new key. @greath AACS MKB costs 1.5K USD, and another two hundred dollars for electronic delivery. Additionally,there is a one time cost between 3K and 10K USD upon setting up the contract. source. You'd think that the studios are paying because they feel that they will lose more then at least 1700 USD per movie due to casual copying, etc. Guarantee to the studios about fixing something in X # of days is silly - if the disc encryption is broken, it is broken, and short of re-releasing the disc, you can't change that fact. If you are a studio that made 20K discs of "Inside Weyland-Yutani", and sold 2K copies world wide, you think that being told that "Yeah, we will give you your next MKB for the re-issuing of this title for free" would help? ("Inside Weyland-Yutani" is a made up name, I have no idea if a movie by that name exists) |
3rd June 2007, 02:53 | #99 | Link |
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I imagine that the sales of some movies are so low that they would have been better to master them without aacs and give them away. Well maybe it isn't that bad, but it isn't very good either.
Take a look at the following article about sales: http://www.tvpredictions.com/whip060207.htm |
3rd June 2007, 04:00 | #100 | Link | |
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Interestingly enough, Circuit City had Matrix Trilogy HD DVDs for $19.99. For 3 days. All the orders in quantity of 1 were completed. Don't believe it was a price mistake. Looks like more like the guerilla attack from the HD DVD camp. People who didn't have the HD DVD players were buying and THEN getting HD DVD players. Things are going to be interesting, but my bet BD will lose. Anyway, we have about a hundred releases to enjoy soon. Thanks to all. |
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