Encryption keepers

-- Video Business, 9/2/2005

SEPT. 2 | When the Blu-ray Disc Assn. agreed to incorporate into its high-definition format the Self-Protecting Digital Content system to bolster its basic copy-protection scheme, it touched off a dispute among studios over the best way to prevent unauthorized disc copying.

Studios in the Blu-ray camp argue the planned implementation of the copy-protection scheme dubbed the Advanced Access Content System is too cumbersome to respond quickly to hacks. And they claim its system for revoking hacked encryption keys works only for software-based players, not stand-alone set-top hardware.

Those in the HD DVD camp, which opted for an AACS-only approach, claim that SPDC’s system for verifying the integrity of both the disc and the hardware before playback could actually expose the AACS encryption keys, making hacks more likely.

The argument is far from over. But it’s also far from the only stone roiling the copy-protection waters these days, as the studios, IT industry and hardware makers struggle to cope with a host of new technological challenges and fix a few old ones.

For instance, officials from the three industries will consider at a series of meetings beginning this week in Los Angeles a proposal to incorporate into new DVD players the means to detect watermarks in camcorded theatrical films. That proposal arose in response to still other initiatives to try to accommodate various new business models, including movie downloading, DVD burning and home networking, while maintaining robust digital rights management.

According to sources involved in the proceedings, at least one operator has pitched the studios on a plan to permit users to burn the movies they purchase from the service onto a DVD. To do that, however, changes would have to be made to the terms of the Content Scrambling System license that governs DVD players and recorders.

While the studios want to be open to new business models, they also want to take the opportunity of revisiting CSS to go back and plug some holes in the system that have become much more glaring since CSS was adopted in 1997.

First among those is the inability to detect a watermark in a camcorded copy of a movie, even if one has been embedded in the theatrical print.

So the studios are proposing to adopt the watermark-detection feature developed by Microsoft for AACS into CSS and bake it into all new DVD hardware and software players. In exchange, Microsoft—or others—would be allowed to implement burning of a rights-managed copy of a paid download.

Should the deal get done, of course, the next step would be to settle on a standard watermark, a quest that has tied the industry in knots more than once in the past.

Currently, the leading candidate is probably the Verance system adopted two years ago by Universal. But other watermark developers, such as Macrovision, can be expected to raise their hands as well.

Meanwhile, the studios have also been working closely with Microsoft to incorporate strict copy-protection measures into the next-generation of Windows—now christened Vista.

The most notable fruit of those discussions is a technology called “Protected Video Path,” which is a scheme for ensuring that encrypted content remains encrypted as it passes from the PC to a monitor, TV set or any other device connected to the computer, or from one component to another within the PC itself.

Basically, it will make parts of the PC inaccessible to the user, which is already provoking howls of protest from those who believe you ought to be able to access all parts of your own computer.

Protected Video Path will also check to see what sorts of connectors are being used to transfer video from one device to another, and if they’re not the type that support DRM rules, the operating system may block the transfer, or at least down-convert the video to a lower resolution.

The goal is to prevent high-def content from being captured and copied at some unencrypted juncture. But it’s effect could be to alienate the very high-def enthusiasts the studios are hoping to woo.