The Blu-ray Discs Association (BDA) has chosen the Advanced Access Content System (AACS) to protect movies and music stored on the next-generation optical storage format.
That’s no great surprise. The BDA has hinted in the past that it was likely to adopt AACS, which is being developed specifically for the successors to today’s DVDs.
Indeed, Blu-ray’s rival format, HD DVD, also incorporates AACS.
However, the BDA has adopted two extra levels of security. The first is the so-called ‘ROM Mark’, which is intended to identify a given disc as genuine. Designed to defeat counterfeiters, the mark can only be stamped on discs by authorised mastering equipment.
The second security strand is dubbed ‘BD+’ and is geared to hindering attempts to crack the encryption technology shielding the content. Essentially, it allows the BDA to update the encryption scheme should the current technique be cracked. If a coder comes up with the Blu-ray equivalent of DeCSS, the BDA simply updates the format’s crypto engine on all future releases, limiting the volume of content that can be nabbed. BD+ also locks down players that have been tampered with to bypass the security system.
HD DVD supporters were quick to claim their favoured format’s copy protection was no less secure than Blu-ray’s.
“HD DVD’s content protection system provides the highest level of advanced copy protection to meet content owner’s needs and the rigors of consumer demand,” claimed Mark Knox, from Toshiba’s HD DVD Promotion Division.
Of course, that argument is founded in HD DVD’s use of AACS - currently still in development, even though it was due to have been finalised earlier this year - and its “synthesis of high level security, including renewability, proven reliability, cost effectiveness and flexibility, as well as superior implementation in real-world devices”.
In short, the HD DVD camp is saying AACS is enough - the concept of renewability enshrined in BD+ certainly appears to be part of the AACS specification. Blu-ray’s addition of the BD+ system on top of AACS may simply be a sop to content providers, and if it persuades them that Blu-ray is the safer system, then it will have done its job.