BackupHDDVD v1.00 now online
p2pnet.net News:- Many an anal sphincter of the corporate kind clenched severely when, just before Christmas, the news broke that someone had hacked the AACS (Advanced Access Content System) DRM which is supposed to stop “unauthorized” HD-DVD and Blu-ray copying.
“I just bought a HD-DVD drive to plug on my PC, and a HD movie, cool!” – posted Muslix64 on the Doom9 forum. But, he went on, “when I realized the 2 software players on windows don’t allowed me to play the movie at all, because my video card is not HDCP compliant and because I have a HD monitor plugged with DVI interface, I started to get mad… This is not what we can call ‘fair use’! So I decide to decrypt that movie. I start reading the AACS specification I have found on the net. I estimate it will take me about 4 weeks of full time job to decrypt that. I was wrong, it was in fact, easy…”
The result was BackupHDDVD. Muslix64 also promised a new version for the new year and Lo! – he delivered, says Michael O’Connor on effectu.
“The new version includes volume key support, partial resumes, and a new file system,” he says, adding:
“For those of you who don’t remember, BackupHDDVD allows users to back up their HDDVDs by circumventing the AACS encryption scheme. I’ve been doing some research on this, and while the code looks legitimate, it seems that no one has been able to successfully back up their HDDVDs due to the fact that no one can find the keys. If anyone has been successful, they haven’t posted anything.”
O’Connor includes Mirror 1 and Mirror 2.
Said an update comment on p2pnet’s original story:
It is Jan 2, and muslix6 has released an updated program as promised. It is still to be determined whether or not this is a hoax or not though, as no keys have been provided, and many people do not have the means with which to test out the software provided. While I do own the Xbox 360 HD-DVD accessory myself, I do not have the technical knowledge required in order to get the keys needed to actually decrypt movies. Same with most folks I would assume. Right now the only thing of any real value is that it has lit a fire of interest out there, so hopefully some enterprising fellow will take what muslix6 has started the rest of the way.
It’s probably worth noting that when this information became available at Christmas, I almost immediately canceled my order at Amazon.com for a rather expensive quantity of HD-DVD movies. Right now I only own several movies plus the Microsoft drive, so I don’t have a lot to loose if I put things on hold for now, or should Blu-Ray win. Having purchased a brand new HDTV recently, I am really quite desperate for HD material. I only went with HD-DVD because the drive accessory was so cheap. I would be just as happy with Blu-Ray. Just so long as I can eventually get my HD fix, I’m happy lol. Anyways, because of all this I was inclined to overlook the fact that there was a format war even going on. It’s this news regarding AACS that has made me pause and take stock of the situation though, and what I’ve decided is that maybe it would be better to wait after all, and see what results from it.
See, while some folks see this news as a confirmation that HD-DVD has won the format war, my belief is that HD-DVD may have just as easily lost the format war. If this news about decrypting AACS has any truth to it, which it may, and combined with things being so early in the format wars game, it is just as likely that all remaining studios supporting HD-DVD might just jump ship and swim over to the other side, effectively killing HD-DVD in the process. It doesn’t matter how badly one might want HD-DVD to win, and I have no doubt that those whom are happy to see this recent news regarding AACS being cracked have all their fingers and toes crossed that it will. But what good is a format that all of the studios refuse to stand behind?
Over on Doom9, “I spent the last few days reading a lot of articles on BackupHDDVD, reading a lot of people’s post/comments on various websites,” says Muslix64, continuing.
This is the time to set the record straight about this new tool and what the impacts are.
First I need to clarify some points.
Revocation:
In the AACS system, there is 4 types of revocation:
Drive revocation
Host revocation
Device revocation (with MKB)
Content revocation
There is no such thing as “title key revocation” and “volume key revocation”
————-
Now, here is a list of affirmations I have seen lately.
Affirmation 1: You did not break AACS, just the player
My comment: I did not break AACS, but I find a way to decrypt movies and I have bypassed all the revocation system.
Not that bad…
Affirmation 2: The BackupHDDVD circumvention tool won’t last long
My comment: As long as insecure players will exist, it will last…
And insecure players will always exist, in fact you can extract keys from any player! Some players are just easier to extract the key from. Being lazy, I prefer to extract keys from an insecure player than a secure one.
And the AACS spec says “Device keys must be protected!” but they did not said that about volume key, fatal mistake!
Affirmation 3: The keys can easily be revoked.
My comment: What keys are you talking about?
As I stated before, there is no such thing as “title key revocation” and “volume key revocation”. If someone publishes only volume keys, there is no way to know from which player these keys where extracted from, making the revocation system useless. They can do content revocation, but to revoke what? All movies before 2007? They can do player revocation, so I will just change the player I’m using, big deal…
So what is the AACS revocation system good at?
It is good for that scenario:
Someone post on the net, a tool that do the complete decryption automatically. Off course the program use stolen device keys from an official player. They (AACS and friends) will eventually get their hands on this program, look at the device keys and revoke them. Making that player unable to play new titles. But the author of this program can pre-extract a bunch of devices keys from different players and release them, one at the time, when the previous one have been blacklisted. The AACS spec says “Device keys must be protected!” so I suppose they put more effort in protecting these keys then the volume key in memory.
Affirmation 4: BackupHDDVD is nothing, only one person out of a million have the technical skills to extract keys.
My comment: BackupHDDVD is a proof of concept.
Picture this:
Few skilled persons can do massive volume key extraction, and send the keys to a central server on the internet. Then, they create an easy to use decryption program, with a nice GUI that do online key recovery. That way, my father and your father can backup movies.
Or they can send the keydb.cfg file on P2P networks (BitTorrent, E-Mule, etc..)
See the problem now?
Affirmation 5: You can extract keys from software player on personal computer but not on hardware player.
My comment: It’s easier to extract keys from software player, but it also possible to extract keys from hardware player (the set-top box in your living room!)
Conclusion:
The attack I describe in “Affirmation 4″, is not here yet, but it’s coming. So I give MPAA and AACSLA a head start. Start to think what you can do about that.
To totally block this attack, they need to put different keys on every disk! Now, they only have different keys for different movies. I don’t know about the manufacturing process of the disk. This solution may not be possible.
The best they can do, is doing shorter manufacturing run of a particular movie, so it would be difficult to get your hand on every “pressing” of a movie.
When they design AACS, they assume people will look for the device keys. I don’t care about device keys. I do care about volume key. Having the device keys mean that you have to re-implements all the complex crypto and do the full AACS process.
I leave all this dirty job to the player and recover only the volume key.
There is 3 important things in cryptography:
1-Private key protection
2-Private key protection
3-Private key protection
Did I break AACS? I don’t know. What do you think?
I’m not going to work on this anymore, I’m taking a vacation!
Stay tuned 
If your Net access is blocked by government restrictions, try Psiphon from the Citizen Lab at the University of Toronto’s Munk Centre for International Studies. Go here for the official download, here for the p2pnet download, and here for details. And if you’re Chinese and you’re looking for a way to access independent Internet news sources, try Freegate, the DIT program written to help Chinese citizens circumvent web site blocking outside of China. Download it here.
Also See:
hacked the AACS – Decrypt AACS movies, December 29, 2006
effectu – BackupHDDVD v1.00 Released, January 2, 2007
grilling could be bad – End of the RIAA terror reign?, January 1, 2007
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