It was predicted by anyone that delights in copy protection getting cracked (not us) that the copy protection of both of the new high definition DVD formats, HD and Blu-ray, have now been broken to varying extents.
What seems to have happened is that a number of encrypted film copies have been discovered on internet file sharing services along with their decryption keys.
The New York Times and other US papers, and some of the techie web sites have all been following the developments over the last week or so.
The Toshiba HD DVD format appears to have been broken fully, by two separate groups and Blu-ray only broken a film at a time as the film keys are discovered and published.
It was a month ago that someone calling themselves “Muslix64” released free software that lets users make copies of HD DVD movies, but it requires the publishing of each key. That same hackers with assistance and credit to other hackers, has now managed the same on Blu-ray it seems.
As we understood it the AACS DRM scheme for HD DVD optical discs was never supposed to be renewable and revocable, so that capability needed to be added in another protection layer if at all. One source suggests that all that has happened is that a single DVD player has been taken apart and the hidden decryption key that decrypts all of the decryption keys on the discs themselves, has been found.
Using this, for as long as there are discs out there that have keys that this player can decrypt, it will remain vulnerable, but future new discs can be made so they don’t decrypt with this player. That’s all very well, but then the pirate only has to take apart another new player and the runaround starts again.
Back in August 2005 the Blu-ray Disc Association publicly adopted what it described as three parallel content protection technologies for its DVD discs and players.
It elected to use AACS, BD+, a Blu-ray-specific enhancement for content protection renewability, and ROM Mark, to guard against mass production piracy.
The Advanced Access Content System came out of an organization set up in 2004 by IBM, Intel, Microsoft, Panasonic, Sony, Toshiba, Disney and Warner Brothers.
Given that the organization was set up specifically to replace the simply and easily duped CSS (Content Scrambling System) that protected content on first generation DVDs, and that members included both Sony, driving the Blu-ray technology effort and Toshiba, driving the alternative HD-DVD standard, then it always seemed likely that both flavors of High Definition DVDs would use AACS.
AACS is supposed to allow content to be copied onto local players in much the same way as Microsoft’s DRM system or Macrovision’s CDS DVD protection system, but only allows copies of content to be copied once, and this is encrypted, and with a new decryption key for each device it is copied onto.
The digital copies themselves cannot be copied, and by adding what limited analog copy protection there is available (mostly all patented by Macrovision) that more or less is meant to sew up the copy protection.
It now looks like this, on its own, has not worked. Everyone out there, say loudly, ‘I told you so.’
BD+ includes the renewability elements that are missing from AACS, but the only way to revoke keys inside players is to place a special code revoking them into subsequent discs. The best way to track piracy it is to put a watermark which binds the cryptographic key to the output analog and that’s what the other protection that Blu-ray has added does. This would mean that any copies of Blu-ray played material that are copied by re-encoding analog outputs, will identify the player that it came from. Of course if a digital copy is made and the decryption key found, that’s not much of a defense.
Mistakenly commentators have been blaming these layers for the increased expense of the Blu-ray player, but it doesn’t really have any effect on the price, although deciding on these protections may have taken time and delayed the Blu-ray devices.