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AACS Device Key Found
Posted by
kdawson
on Sat Feb 24, 2007 07:20 PM
from the dominoes dept.
from the dominoes dept.
henrypijames writes "The intense effort by the fair-use community to circumvent AACS (the content protection protocol of HD DVD and Blu-Ray) has produced yet another stunning result: The AACS Device Key of the WinDVD 8 has been found, allowing any movie playable by it to be decrypted. This new discovery by ATARI Vampire of the Doom9 forum is based on the previous research of two other forum members, muslix64 (who found a way to locate the Title Keys of single movies) and arnezami (who extracted the Processing Key of an unspecified software player). AACS certainly seems to be falling apart bit for bit every day now."
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HD DVD's AACS Protection Bypassed 161 comments
Mr. BS writes "Playfuls.com is running a story how HD DVD's AACS protection has been compromised. Although the video of the hack leaves much to be desired, the source code has already been made available. Feel free to start backing up your HD DVD's whenever you feel the need."
[+]
Decryption Keys For HD-DVD Found, Confirmed 473 comments
kad77 writes "It appears that, despite skepticism, 'muslix64' was the real deal. Starting from a riddle posted on pastebin.com, members on the doom9 forum identified the Title key for the HD-DVD release 'Serenity.' Volume Unique Keys and Title keys for other discs followed within hours, confirming that software HD-DVD players, like any common program, store important run-time data in memory. Here's a link to decryption utility and sleuthing info in the original doom9 forum thread. The Fair Use crowd has won Round One; now how will the industry respond?"
[+]
AACS Cracked Again 306 comments
EmTeedee sends us to a blog post for a summary of the latest results in cracking AACS, from the Doom9 forums (as the earlier cracks have been) — after the DVD Security Group said it had patched the previous flaws. From the DLTV blog: "This time the target was the Xbox 360 HD DVD add on. Geremia on Doom9 forums has started a thread on how he has obtained the Volume ID without AACS authentication. With the aid of others like Arnezami they have managed to patch the Xbox 360 HD DVD add on... It appears that XT5 has released [an] application that allows the Volume ID to be read without the need to rewrite the firmware. This would mean that anyone could simply plug in the HD DVD drive and obtain the Volume ID from any HD DVD without the hassle of flashing it."
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Will they actually do it? (Score:5, Interesting)
Will they actually revoke these software players from all new disks?
Its time for them to put their money where their mouth is and actually block access to these broken players.
If they allow it to continue, all their movies will be piratable (insert oh noes! here).
I wonder how pissed off people will be if they can't play their new movies?
Re:Will they actually do it? (Score:5, Interesting)
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Fortunately, it's still in infancy :) (Score:5, Insightful)
So, of course; don't buy them. Tell your friends not to buy the, and spread the word. If technology was selected based on worth and merit, we'd all have been using beta-max and mini-discs. But consumers don't always go for quality, innovation or convenience. Most often they like whet their friends have, they like what they already have, and sometimes? They just follow the pr0n industry (uh oh, did i just predict the HD-DVD?) THe point being, this one is easy to 'nip in the bud.'
Now, if you were to start a large-scale boycott of xxAA products? That would rock the boat. But I'm not holding my breath for you.
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Re:Will they actually do it? (Score:5, Insightful)
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Re:Miserable? (Score:5, Insightful)
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Re:Miserable? (Score:5, Informative)
So, am I not "supposed" to watch my DVDs on my old TV? The macrovision protection makes the picture nearly unwatchable. The TV is very nice, and does the job well. Why should I have to throw away a perfectly good TV and buy a new one just to watch a DVD? It doesn't make any sense - if I have to buy a new TV, that's less money for me to spend on DVDs, so the copy protection would actually reduce their sales.
Likewise, have you never bought a DVD from another country? If you're not supposed to do that, then why can I buy DVDs from another country? Sure, you can get region-free DVD players, but not everybody has one - and with "RCE" protection, some titles won't even work on some region-free players. And region-free players are technically illegal in some places.
I also like to watch movies but some titles won't let me go straight to the movie, and instead force me to sit through unskippable ads and FBI warnings. I even had one disc that I bought, which made me sit through a quite long lecture about the evils of piracy, telling me how people who copy DVDs are funding terrorism and destroying the industry. Ironically, it was quite simple to make a copy of that DVD, with the anti-piracy ad removed. If they didn't have that unskippable propaganda at the beginning. If I ever get another disc with that ad, I'm going to return it as defective. I paid to watch the movie, not to be lectured by propaganda.
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Re:Will they actually do it? (Score:5, Insightful)
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Re:Will they actually do it? (Score:5, Insightful)
Assuming they keep their word, and revoke the keys as they're found, software players will become nearly unusable, with patches every few weeks to update the key, attempt to obfuscate it more, and make it usable with new disks again. If they go that route, it's only a matter of time until software HD-DVD/BR players are permanently blacklisted and cease to exist. Consumers won't like that much. We'll see special cables running from new drives to new video cards, because consumers will not put up with a lack of being able to play HD discs on their computers. And the ones that bought software players will be ROYALLY pissed.
If they let it slide, or just sue the people who found the key in the memory dumps, but do not revoke software player keys there's STILL no way to put the cat back in the bag - HDDVD/BR content protection is finished.
Which way will it go?
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key in memory - on some PCs yes (Score:5, Insightful)
It will work something like this:
There will be two channels of data, one from the media source to the dongle, and one from the dongle to the playback device.
The dongle will decrypt data from the media source, or possibly ordinary RAM. In some cases, will be done with the aid of software tokens purchased from rights owners. In others, it will merely verify region, time-expiration, and other restrictions embedded in the media are complied with. In some cases, part of the key will be downloaded from the Internet in real time, or a time-bombed key will be renewed at regular intervals.
The dongle will re-encrypt the data so the playback hardware can play it, but memory-snoopers can't access it.
The dongle will be a "black box," protected by hardware features and possibly legal protection: "Tamper with this for the purposes of understanding it and go to jail."
The dongles will be handed out like candy for little or not profit, but they will be revoked individually if any one is compromised. People concerned about privacy and tracking implications will trade dongles or simply buy them by the bucketful.
I don't know if these dongles will be USB dongles or if they will be on a faster bus or maybe even connected directly to the video playback circuitry.
Mark this post, it may prove useful in challenging future dongle patents.
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Re:key in memory - on some PCs yes (Score:5, Insightful)
First off, this isn't even remotely new. Dongles for copy protection are as old as the concept of copy protection. AutoCAD used a dongle. I'm sure there are dozens of other examples. But they haven't been widely implemented for the same reason this won't be. Cost.
It's too expensive to ship a sophisticated $20 part with a pressed disc that costs $1 to make and you're selling for $20. Dongles have only really been used in very expensive software packages for this reason.
Also, the whole content industry is moving to a "download over the Internet" model. Bill Gates was right when he said this is likely to be the last physical format war. Any solution that is not software only is a non-starter in this context.
The dongle will decrypt data from the media source, or possibly ordinary RAM. In some cases, will be done with the aid of software tokens purchased from rights owners. In others, it will merely verify region, time-expiration, and other restrictions embedded in the media are complied with. In some cases, part of the key will be downloaded from the Internet in real time, or a time-bombed key will be renewed at regular intervals.
If you're going to require an internet connection, what's the point of the dongle? Just make the user verify the key in real time against the server for every play. This would already have been implemented if they thought users would stand for it. They won't.
The dongle will re-encrypt the data so the playback hardware can play it, but memory-snoopers can't access it.
This makes no sense. The playback hardware presumably doesn't have encryption capability. If it does, and it has the encryption hardware built in, what is the point of the dongle? You're also expecting a DONGLE to decrypt, encrypt, and transfer HD video in full resolution all in real-time. That's a pretty beefy dongle. See above for the cost issues.
I think it's worth expanding on this point. Do you really understand how sophisticated the dongle you're talking about would have to be? It would have to include a CPU, memory, and storage to do the encryption. And how they're totally useless unless you ship a SEPERATE one attached to EACH video you want to play? The keys have to be individual for each "disc" (or instance of video) and ROM-burned, not flashable. The idea of some sort of "dongle vault" or multikey that allows you to used multiple stored keys is fatally flawed for a vast number of reasons. The most basic being that it would make hacking the dongles extremely attractive.
Now if you're thinking of "embedding" this dongle into the computer itself, it's been done. This is the whole concept of the TPM chip and concerns about it being used for DRM. This solution is also not feasible for any number of reasons.
I don't know if these dongles will be USB dongles
No, it will have to be a proprietary interface. USB is too easy to sniff.
maybe even connected directly to the video playback circuitry.
So users are going to have to crack their case open every time they want to play a video? I think not.
Mark this post, it may prove useful in challenging future dongle patents.
None of this is either novel or practical.
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Re:Will they actually do it? (Score:5, Informative)
Breaking a major hardware player is a big deal, however breaking a software player is fairly trivial in the long-run as long as it can be upgraded.
Breaking a single hardware device won't be a big deal, either, since the key revocation scheme allows that single player to be revoked (not the brand, not the model, not even the factory batch -- that single, specific physical player). What would be big would be finding a way to easily extract the keys from a model, or, even better, a whole class of players. Then, the hackers could just do a player every few weeks, and the worst case for those of us who like to back up the movies we buy is that we'd have to wait a few weeks after the release before we could back it up.
The way AACS key revocation works is that there is a massive binary tree of binary trees of possible encryption keys. The "main" tree is 31 levels deep (allowing for 2^31 possible player devices) and each node has a number of "shadow" trees associated with it (specifically, nodes in layer n of the main tree have n-1 shadow trees). Each player is given a carefully selected and unique set of ~500 keys, from which it can derive an enormous number of keys -- almost every key in that big tree of trees, in fact.
The "almost" in the last sentence is important.
Assuming no players are revoked, each disk needs only have few copies of the media key[1], each encrypted with a "processing" high up in the tree. All players have keys needed to derive[2] these processing keys. When a player is revoked, the publishers carefully select a set of processing keys to use so that every player *except* the revoked player can derive the processing keys. There's a fairly simple algorithm to select such a set of keys, and the structure of the trees ensures that for any set R of revoked players, no more than 2|R| processing keys need to be used (|R| means "size of R", in case that's not obvious).
Each encrypted copy of the media key consumes 32 bytes of disk space, so, assuming a million players have been broken and revoked, each new disk will "waste" 32 MB on encrypted media keys. Given the capacity of HD-DVD and Blu-Ray disks, 32MB is a pittance, so it really is practical for publishers to revoke every key that is extracted and published -- the hard part will be finding them all.
ANY software player will have to put their key in memory at some point while it's running, the new key will be found quickly. And the keys for almost all software players will be found.
Yep, that's a seriously hard problem to solve -- especially when you consider that time and manpower are 100% on the side of the attackers. The attackers have a disadvantage in that they have to work with binary-only code, but if this goes on for long enough, I'll bet the major software players will be so thoroughly reverse engineered that this will cease to be a very meaningful disadvantage.
Large-scale DRM simply cannot work. If you give the devices to enough interested and technically skilled people, they will be broken again, and again, and again.
And, of course, if publishers *did* somehow manage to get ahead of this game, it would just mean that the hackers would keep the keys to themselves, publishing them only to small groups of trusted friends -- all of whom would be ripping movies like mad and making torrents available so that everyone else can get them.
[1] The Media Key is used to encrypt the title keys, which are used to encrypt the titles. There are generally multiple titles per disk -- usually one for the main feature, and others for each of the extras, some for bits of the animated menus, etc. I've been puzzling over exactly how many copies of the media key are required in the no-devices-revoked case, and I haven't been able to figure it out yet. An answer and explanation from someone who understands this stuff well would be appreciated.
[2] The keys given to the players are called "device keys". The players l
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Re:Will they actually do it? (Score:5, Informative)
Correction -- If a million players are revoked, up to *two* million copies of the media key will be required, consuming 64MB of space on each disk. However, that's only if the million broken devices are selected so that revocation is maximally inefficient. If they're selected at random, on average only ~1.25M MKB entries are required, so only 40MB of the disk must be used for MKB entries. That's 0.2% of a single-layer HD-DVD and 0.08% of a dual-layer Blu-Ray. Or, it's about 20 seconds of HD video, assuming that a single-layer HD-DVD will hold two hours. If a dual layer Blu-Ray disk contained video encoded at such a high bit rate that it would only hold two hours, the MKB block would eat up space equivalent to six seconds of video -- and that's with a *million* revoked keys).
In practice, of course, the time unavailable for video will bever be a problem. If the movie and the MKB can't both fit, you just tweak the encoding to drop the average bitrate by a 10-20 kbps. When you're encoding normally at 8,000-20,000 kbps no one will be able to see the reduced quality. Also, even regular DVDs are rarely within 100MB of being full. There's plenty of room available for "large" MKBs.
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Re:Will they actually do it? (Score:5, Interesting)
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Go to plan B (Score:5, Insightful)
Sure it will be somewhat inconvienient and more expensive for customers, but that's the price they are choosing to pay when they turn a blind eye to piracy.
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Introduction of hardware DRM (Score:5, Insightful)
Of course such restrictions would make debugging your own programs harder if it was always on.
Re:Introduction of hardware DRM (Score:5, Insightful)
This is crackable anyways. The original Xbox was cracked by someone building their own data sniffer hardware installed on the system bus. No kidding. People will go to pretty much any length, including hardware modification, to break out of constricting usage limitations (aka DRM)...
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This is great news (Score:5, Interesting)
Ugh (Score:5, Insightful)
- WinDVD is not handling its device key in a secure manner
- WinDVD cannot be trusted
- WinDVD won't be getting another player key
Or even worse:
- WinDVD did its best to protect its device key
- It's impossible to protect a device key in a program that people can reverse-engineer [true]
- We'd better not allow any software to read AACS-protected content
Although this may all be moot anyway, as they can extract future process keys with relatively little effort (though it'll be a lot more effort if hackers have to break hardware systems instead of software).
DRM is provably insecure (Score:5, Insightful)
Re:All your video are belong to us (Score:5, Funny)
MPAA: What happen ?
RIAA: Somebody set up us the bomb.
RIAA: We get signal.
MPAA: What !
RIAA: Main screen turn on.
MPAA: It's you !!
J.Q. Public: How are you gentlemen !!
J.Q. Public: All your video are belong to us.
J.Q. Public: Your revenue stream are on the way to destruction.
MPAA: What you say !!
J.Q. Public: Your business model have no chance to survive make your time.
J.Q. Public: Ha Ha Ha Ha
RIAA: MPAA !! *
MPAA: Take off every 'Lawyer' !!
MPAA: You know what you doing.
MPAA: Move 'Lawyer'.
MPAA: For great injustice.
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Re:Okay that does it (Score:5, Informative)
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Re:Okay that does it (Score:5, Informative)
AACS uses a bunch of different keys in a hierarchical structure. Gradually, the cracks have been revealing keys higher and higher up the food chain. As I understand it, this is a bottom-up description of AACS's key structure:
At the lowest level, every piece of content is encrypted with a Title Key, which is unique to at least an individual title, possibly a particular printing of the title. The original cracks revealed the Title Keys for individual titles one at a time. These can be used to decrypt the content, but don't break the scheme, just the encryption on an individual piece of content.
The Title Key is stored on the actual media, encrypted by the Volume Unique Key, which is unique to a given title.
The Volume Unique Key is the result of a keyed hash of the Volume ID (stored on the media) and a Media Key, which is unique per title.
The Media Key used is generated by combining the Media Key Block (stored on the media) with a key unique to the decrypting device. Each device has a different key, but generates the same Media Key.
I'm not entirely sure why so many keys are used, but that's basically how the scheme works. Previous cracks were based on revealing keys that were title-specific. This one has revealed a device-specific key, which means that until the key is revoked, which would cause all future discs to no longer play on that particular player, any piece of content can be completely decrypted.
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Re:Okay that does it (Score:5, Informative)
It's more news in that it could make HD content decryption as universally accessible as DVD decryption currently is. A lot of people might want to extract their HD content but not have the know-how or motivation to do anything beyond "download this program, hit start", though it's less news since I've heard there are already programs that will do that using a list of title keys that's periodically updated over the Internet.
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Re:Okay that does it (Score:5, Funny)
It seems to go on and on forever. But then you get to the end and a gorilla starts throwing barrels at you.
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Not if you're trying to prove a point ... (Score:5, Insightful)
If you're trying to demonstrate that DRM is futile waste of energy, it's in your best interests to release as early as possible.
Releasing an exploit a couple of years after the technology is first released gives people the impression that the DRM was "good" for those two years. On the other hand, releasing the exploit a week later drives home the point that the copy-protection racket is selling nothing but snake oil.
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