AACS Copy Protection For Blu-ray Disc And HD DVD Reached

By Gary Reber

February 20, 2006

At a February meeting of the AACS LA negotiators reached an interim license on the final specifications of the new Advanced Access Content System (AACS). Prio to this interim agreement, insiders were reporting that an important member of the Blu-ray Disc Association was still voicing concerns about the interaction of AACS and the additional BD+ protection for Blu-ray movies. Without the AACS specification, which both formats share, the secret copy protection encryption keys that manufacturers of drives and media and disc replicators need in both format camps cannot be produced. The keys are needed so that manufacurers of both Blu-ray Disc and HD DVD players can implement AACS and thus can start to press discs and ship players capable of reading the discs. Without such encryption keys, the announced first Blu-ray Disc drives, HD DVD drives, and stand-alone players at the end of March would have been delayed probably at least until the end of April. But now plans can stay on schedule as is the case with Toshiba’s planned late-March player introduction and with plans for their national “A Defining Moment In Home Entertainment” HD DVD promotional tour (see accompying story). The first HD DVD titles are slated to arrive March 28 from Warner Home Video. Samsung and Pioneer plan to start shipping Blu-ray Disc players in May. AACS is a security requirement of the Hollywood movie studios who are all insisting that such copy protection be included in all drives to thwart pirates. Without AACS, high-resolution movies cannot be authored or played back. The renewalable AACS protection keys are designed to block manipulated drives. The BD+ scheme provides additional protection for Blu-ray discs only. It was offered as part of the “we have more protection than you” approach to appease the major movie studios. BD+ is not part of the HD DVD specification but was reported to be the reason for the holdup, which must have infuriated HD DVD backers. Althought both the Blu-ray Disc Association and the DVD Forum agreed to adopt AACS as the primary copy-protection scheme, efforts among AACS member companies to agree to the finanization of the terms and conditions for implementing the technology have faltered over past months. When the Blu-ray Disc Association announced their additional protection measures in August of last year, it was largely thought that the extra security scheme was there to woo content owners, especially Twentieth Century Fox Home Entertainment, which is not a member of the AACS eight-company consortium. BD+ is a dynamic encryption scheme that allows for changing encryption schemes midstream. Should the encryption be cracked, a Blu-ray Disc content owner can update the encryption scheme and put it on all new discs, thus preventing a single incident from opening up the entire BD specification for the duration of the format’s lifetime. The lack of a dynamic encryption model for DVD is what made DeCSS so disastrous. Once CSS was cracked, all DVDs from then on were crackable. The core AACS scheme deals with this problem, but certain Blu-ray supporters believed that additional protection was necessary. The implementation of the “managed-copy” requirement for AACS-encrypted discs is reportedly impacted by BD+, which Microsoft and Intel contend could interfere with viewing HD disc content over a home network. All AACS-encrypted discs must permit users to “rip” the content to a hard drive under carefully controlled conditions. This provision is regarded as essential by Microsoft and Intel who see this provision as an effective means to integrate the new formats into larger digital home networks based on their technology. As reported by Paul Sweeting in Video Business, “Microsoft, in particular, is keen to include managed-copy capability in Vista, the next generation of its Windows operating system expected to arrive later this year.” Another issue which has incited disagreements has been the types of video outputs AACS-compliant players will be permitted to have and whether they must respect region coding on the discs. There are technical aspects related to the interaction of AACS and BD+ that still require fine tuning before the final specification for AACS can be ratified. And the interim licensing agreement does not resolve all questions surrounding managed copy. Because the first-generation players will be playback-only drives this issue can be addressed at later time in the final agreement.

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