Original URL: http://www.theregister.co.uk/2007/01/23/blu-ray_drm_cracked/

Blu-ray DRM defeated

Copy-protection cracked again

By John Leyden

Posted in Storage, 23rd January 2007 17:39 GMT

The copy protection technology used by Blu-ray discs has been cracked by the same hacker who broke the DRM technology of rival HD DVD discs last month. The coder known as muslix64 used much the same plain text attack in both cases. By reading a key held in memory by a player playing a HD DVD disc he was able to decrypt the movie been played and render it as an MPEG 2 file.

The latest Blu-ray hack was performed by muslix64 using a media file provided by Janvitos, through the video resource site Doom9, and applied to a Blu-ray copy of the movie Lord of War. In this case, muslix64 didn't even need access to a Blu-ray player to nobble the DRM protection included on the title.

Both HD DVD and Blu-ray use HDCP (High-Bandwidth Digital Content Protection) for playback display authentication and similar implementations of AACS (Advanced Access Content System) for content encryption.

The hack sidesteps, rather than defeats, the AACS encryption used as part of the content protection technology used by both next-generation DVD formats. The approach relies on obtaining a particular movie's unique "key" and can't therefore be trivially replicated to rip content across all titles encoded via a particular format, as tools like DVD Decryptor make easy with standard DVD titles.

muslix64 has however posted a 18KB tool that allows other to try their hand at extracting the keys of other Blu-ray Disc movies

BD+, the second type of content protection on Blu-ray, is yet to fall by crackers but this is something of a moot point today as the technology is yet to be widely applied on discs.

Blu-ray and HD DVD both allow for decryption keys to be updated in reaction to attacks, for example by making it impossible to play high-definition movies via playback software known to be weak or flawed. So muslix64 work has effectively sparked off a cat-and-mouse game between hackers and the entertainment industry, where consumers are likely to face compatibility problems while footing the bill for the entertainment industry's insistence on pushing ultimately flawed DRM technology on an unwilling public. ®