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AACS Specifications Released
An anonymous reader writes "AACS, the proposed key management scheme for HD DVD, has finally released preliminary (ver 0.9) specifications. The specs look like CSS on steroids: they use AES instead of proprietary crypto, but other than that they're basically the same. The main difference appears to be that AACS can revoke an entire player model if a hack appears against it, which I guess sucks if you own that kind of player."
The main difference appears to be that AACS can revoke an entire player model if a hack appears against it
In that case, why would any manufacturer in their right mind produce anything under such terms? That would just be insane
The revolution will not be televised. It won't be on a friggin blog either
"The main difference appears to be that AACS can revoke an entire player model if a hack appears against it, which I guess sucks if you own that kind of player."
Player model? What if a hack comes out for PC that allows you to circumvent the copy protection: Does it revoke PCs altogether, only certain disk drives, or what?
Creative Demolition
Here's the big difference...
Gaining access to DirecTV's signal requires hacking proprietary hardware. If PC-based players are ever allowed, reverse engineering will be along the same lines as last time around. It's just so easy to monitor everything your computer is doing in real-time, especially with the help of emulators like QEMU, Bochs, VMware, or Virtual PC.
I used to get high on life, but I developed a tolerance. Now I need something stronger.
Well, what happens to the customers that have a player-model that gets, by no fault of themselves, revoked. Are they reembursed (getting (part of) their money back), or are they just left with a piece of worthless, but costly junk ?
Even worse : you have no way of knowing if the player you are going to buy is on the list of players shortly-to-be-revoked, or worse yet : allready revoked.
How's the "you should be able to use a bought commodity for a reasonable time"-law come in play here ?
It may be the strongest encoding out there, but who cares? What stops me from plugging the video output of a dvd player into my video capture card and recording off of it? Sure, the quality won't be as good, but it will still work.
I wish they simply wouldn't scramble content in the first place. 99.9% of the people who buy the dvd and would need to break the encoding have a LEGITIMATE reason to break said encoding (backup, copying to laptop so it's not necessary to carry discs on trips, etc).
If they can revoke keys, then we can DoS the keyspace. There's no need to crack any crypto. All we gotta do is trick them into deprecating keys.
How many people are still running windows 98? How many people know how to set the clock on their vcr?
You DoS the keyspace eventually people won't be able to play commercials. Then the productions don't get their money. Then the system does either of 2 things. 1: every screen goes black and there is no tv or 2: they give up and take off the crypto so the ads work again.
Key revocation is a bigger security risk than keys in software dvd players because you can do more than opening up a file to everybody. You can lock everybody out of it as well.
This idea (starting with hdcp I guess) just opens up more vectors for attack. Now we have a social engineering vector and a keyspace vector in additon to a locally stored key vector (css).
In that case isn't the cat already out of the bag? Not like they can on the fly say that all your HD-DVDs won't work in the morning... The only thing that they can do is prevent future media from playing on that model of HD-DVD player.
We have seen that play before, cripple the next hot DVD to hit the market and what do you get? A ton of product returns and pissed off customers. The encryption may be more advanced, but when you want to give everyone consumer devices with the universal key to the castle... It's only a matter of time before someone figures out a way to copy it.
Consumers' best interests would be best served my using NO crypto. All that crypto hardware/software costs money to develop and manufacture. Guess who pays for it in the end?
Remember Apple IIe games that wrote bad sectors or extra sectors and other such nasties to try and stop people copying 5-1/4 inch floppies?
Remember SecureROM and others making CD copy protection by intentionally leaving broken sectors on CDs - making them unburnable in nearly all of the burners at that time?
Remember that DVD's were once uncopyable?
Remember when Pay TV signals were encrypted by obfuscating their signal with some analogue hardware?
Remember when they started using proprietary digital encryption for Pay TV (Irdeto)?
Every time someone offers up content in some protected form, someone is going to break it. Period. Even if they can't break it, someone will use a legitimate DVD player and screen/sound grab their favorite movies using a capture card.
The only difference I see now is that the companies implementing these measures are monopolies whereas they used to smaller players in their respective markets. This might mean that they can push some legislation through to discourage copying but nothing will ever stop it IMHO.
Keeping on doing the same thing, and expecting a different result.
They don't care about piracy. This isn't, and never has been, about piracy.
What they care about is control.
They care about linux distributions adding support to play HD-DVD movies, but not paying license fees to the DVD forum.
They care about HD-DVD players cropping up that allow you to fast-forward past the trailers at the beginning of the movie, the ones where a licensed player, when you say "fast forward", says "no".
They care about people making players behind their back which openly flaunt the "region locking" mechanisms that make regional price discrimination possible.
They care about products like DVDXCopy which allow consumers to exercise their fair use rights and do God knows what with the products they purchase.
These are the things they're trying to stop or hinder. Their choice of technology simply reflects that. AACS will do little in the short run and nothing in the long run to prevent piracy. But the legal barriers the media companies paid to erect will allow AACS to keep all four of the above things off of the general commercial market.
Irritable, left-wing and possibly humorous bumper stickers and t-shirts
Please do not crack it until its final and distributed in tons of players.
Page 24: Each compliant device is given a set of secret Device keys when manufactured. ...The set of device keys may either be unique per device, or used commonly by multiple devices. ...The [Media Key Block] system is based on a large master tree of keys, with each set of Device Keys being associated with a leaf node of the tree... Further, corresponding to every sub-tree in the master tree is another set of system keys... Thus, the subset-difference tree has to store one encryption per Device Key set revoked, and occasionally additional encryptions to pick up non-revoked sets not covered by the smaller sub-trees. On average, there are 1.28 enrcryptions per revocation.
The document goes on to mention around pages 27 and 28 that devices obtain key conversion data by mechanisms called out in the AACS liscense, and recording devices must verify the signature and determine by its version number field whether a Media Key Block is more recent than the one currently on the media. "Each time the AACS LA changes the revocation, it increments the version number and inserts the new value in subsequent Media Key Blocks."
This says to me that the DVDs you buy will in fact be the transport mechanism for updated revocation keys, and presumably your player will be able to store a lot of them. So movie production companies and distributors must conspire to continually subvert the functionality of a consumer's device, and this does not require the player to be online nor will a firewall help. Once you get yourself locked into the prison of this coded delivery system, your own buying habits will keep adding additional chains to your cage. It is quite insidious, not only are they using military-level technology to control movies, the system is founded on the complicity of the entertainment industry, the electronics industry, and consumers themselves (and the consumer's PC if used) with constant policing and injection of targeted death-messages into the distribution channel. It also looks like the drive can potentially disable media (page 41) and even report hacked hosts/drives by recording onto the media (it seems kind of vague but it is writing a concatenation of the "Binding_Nonce", "Drive_Nonce" and "Host_Nonce" to the protected data area, whatever these things are), which if this is indeed true would I suppose be reported through other PCs/drives of people to whom you lend the media, or maybe through even a shared Internet connection, if you want to try extrapolating this.
Sorry I got ahead of myself. Page 55 talks a lot about online connections, online enabled content and streamed content. It talks about Title Keys and says "the word 'title' is often overloaded. For example a title can refer to a full-feature movie, a TV program, a music album, etc. ... however [we] .. define Title to be a distinct path.. That is, a Title is a logical grouping of content material to be presented in a specific order in time." It also mentions an "Enhanced Device" that is online and can then provide full access to Enhanced Titles that require online connections or extended player functionality. Page 56 mentions a Cacheable Permission that expires after a certain amount of time or include a "do not play until" date, and the XML based Title Usage File is based on global, not local time, which if used must be based on a "secure clock" whatever that is. Oh yeah, on page 59 it mentions the default connection protocol can operate (by https) over Ethernet, firewire, WLAN, etc. so you know this is not just about an HD DVD format but looks like it is trying to take over every device in the vicinity as well. How much you want to bet this will police titles not actually loaded in the player?
I think the cutest part is page 61, where it shows how you can go online with a PIN number and a remote Clearing House server can offer a title
The monopoly given to content owners to determine what others can do with content is subject to some "fair-use" caveats.
Isn't it about time that we, the people who are paying for this content get our fair use rights looked after. Anyone putting DRM controls in place should have a legal obligation to ensure that if if a customer has paid for the right to have access to the content that they also get their fair use rights as well.
It seems to me that the sorts of controlling technologies that are being envisaged here do not safeguard those rights. Isn't it about time we pressurised our democratic representives to ensure that we don't lose them?
In Australia it now is, we are not allowed to create any copy protection circumvention mechanisms. To all you Americans: thanks for nothing.
Last I checked US troops aren't marching house to house in Australia, or occupying the Australian parliament.
Blame your own gutless politicians for your own mess. I don't blame Aussies for Bush being in office, despite the fact that one right-wing Aussie happens to own FOX and had no small part in running the propoganda machine that conviced approximately 50% of the US voters to vote the moron back into office.
You're responsible for your own mess, and the sooner you take your own leaders to task for it, rather than blaming a foreign power, the sooner you'll get it fixed. The same goes for us, by the way. The sooner we start blaming our own leaders for the current mess, rather than boogeymen in caves and Al Q'aide, the sooner our mess here in the states will get sorted out.
I don't expect either country's population to do this anytime soon, however.
The Future of Human Evolution: Autonomy