August 23, 2017

Slysoft Commercializes Next-Gen DVD Circumvention

We’ve been following, off and on, the steady meltdown of AACS, the encryption scheme used in HD-DVD and Blu-ray, the next-generation DVD systems. By this point, Hollywood has released four generations of AACS-encoded discs, each encrypted with different secret keys; and the popular circumvention tools can still decrypt them all. The industry is stuck on a treadmill: they change keys every ninety days, and attackers promptly reverse-engineer the new keys and carry on decrypting discs.

One thing that has changed is the nature of the attackers. In the early days, the most effective reverse engineers were individuals, communicating by email and pseudonymous form posts. Their efforts resulted in rough but workable circumvention tools. In recent months, though, circumvention has gone commercial, with Slysoft, an Antigua-based maker of DVD-reader software, taking the lead and offering more polished tools for reading and ripping AACS discs.

You might wonder how a company that makes software for playing DVDs got into the circumvention business. The answer has to do with AACS’s pickiness about which equipment it will work with. My lab, for example, has an HD-DVD drive and some discs, which we have used for research purposes. But as far as I know, none of the computer monitors we own are AACS-approved, so we have no way to watch our lawfully purchased HD-DVDs on our lawfully purchased equipment. Many customers face similar problems.

If you’re selling HD-DVD player software, you can tell those customers that your product is incompatible with their equipment. Or you can solve their problem and make their legitimately purchased discs play on their legitimately purchased equipment. Of course, this will make you persona non grata in Hollywood, so you had better hire a few reverse engineers and get to work on some unauthorized decryption software – which seems to be what Slysoft did.

Now Slysoft faces the same reverse engineering challenges that Hollywood did. If Slysoft’s products contain the secrets to AACS decryption, then independent analysts can extract those secrets and clone Slysoft’s AACS decryption capability. Will those who live by reverse engineering die by reverse engineering?

AACS Updated, Broken Again

[Other posts in this series]

We predicted in past posts that AACS, the encryption system intended to protect HD-DVD and Blu-ray movies, would suffer a gradual meltdown from its inability to respond quickly enough to attacks. Like most DRM, AACS depends on the secrecy of encryption keys built into hardware and software players. An attacker who discovers a player’s keys can defeat the protection on any disc that works with that player. AACS was designed with a defense against such attacks: after a player has been compromised, producers can alter new discs so that they no longer work with the compromised player’s keys. Whether this defense (which we call “key blacklisting”) will do much to stop copying depends how much time elapses before each leaked key is blacklisted.

Next week marks three months after the first compromised player key appeared on the Internet (and more than five months after cracks for individual discs began to appear). Discs slated for release on Tuesday will be the first to contain an update to AACS that blacklists the leaked keys.

What took so long? One limitation comes from the licensing agreement signed with player manufacturers, which requires that they receive ninety days’ notice before their keys are blacklisted, so that they have enough time to update their products.

Customers who obtained the new discs a few days early confirmed that the previously leaked keys no longer worked. It seemed as if AACS had recovered from the attacks just as its designers intended.

However, a new twist came yesterday, when SlySoft, an Antigua-based company that sells software to defeat various forms of copy protection, updated its AnyDVD product to allow it to copy the new AACS discs. Apparently, SlySoft had extracted a key from a different player and had kept the attack a secret. They waited until all the other compromised keys were blacklisted before switching to the new one.

The AACS Licensing Authority will be able to figure out which player SlySoft cracked by examining the program, and they will eventually blacklist this new key as well. However, all discs on store shelves will remain copyable for months, since disc producers must wait another ninety days before making the change.

To be successful in the long run, AACS needs to outpace such attacks. Its backers might be able to accelerate the blacklisting cycle somewhat by revising their agreements with player manufacturers, but the logistics of mastering discs and shipping them to market mean the shortest practical turnaround time will be at least several weeks. Attackers don’t even have to wait this long before they start to crack another player. Like Slysoft, they can extract keys from several players and keep some of them secret until all publicly known keys are blacklisted. Then they can release the other keys one at a time to buy additional time.

All of this is yet more bad news for AACS.

You Can Own an Integer Too — Get Yours Here

Remember last week’s kerfuffle over whether the movie industry could own random 128-bit numbers? (If not, here’s some background: 1, 2, 3)

Now, thanks to our newly developed VirtualLandGrab technology, you can own a 128-bit integer of your very own.

Here’s how we do it. First, we generate a fresh pseudorandom integer, just for you. Then we use your integer to encrypt a copyrighted haiku, thereby transforming your integer into a circumvention device capable of decrypting the haiku without your permission. We then give you all of our rights to decrypt the haiku using your integer. The DMCA does the rest.

The haiku is copyright 2007 by Edward W. Felten:

We own integers,
Says AACS LA.
You can own one too.

Here is your very own 128-bit integer, which we hereby deed to you:

[can’t display integer]

If you’d like another integer, just hit Shift-Reload, and we’ll make a fresh one for you. Make as many as you want! Did we mention that a shiny new integer would make a perfect Mother’s Day gift?

If you like our service, you can upgrade for a low annual fee to VirtualLandGrab Gold – and claim thousands of integers with a single click!