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Group prepares MPEG-4 encryption

The proposed specification could help address a conspicuous rights management hole in the next generation of the digital media standard.

Aiming to close a long-standing gap in digital rights management for MPEG-4, a streaming media consortium is seeking comments on an encryption specification slated for release in June.

The Internet Streaming Media Alliance (ISMA), whose members include Apple Computer, AOL Time Warner, Cisco Systems, IBM and Sun Microsystems, said it would spend the next two months evaluating public review of the new digital rights management (DRM) specification.

The proposed specification is a way of encrypting streaming media files that would be compatible with existing methods for key encryption and DRM. That would give content providers more flexibility in pursuing their commercial goals, the ISMA said.

"In developing this specification, we spent a significant amount of time gathering feedback from major content owners," ISMA President Tom Jacobs said in a statement. "As a result, our specification does not bind them to utilize specific rights and key management systems or preselected solution vendors. This allows content owners to retain control over critical business processes and related decisions."

MPEG-4, a standard for compressing audio and video files for delivery over the Internet and other networks, is the work of the Moving Picture Experts Group, which also designed MPEG-2 for digital television and MP3 for music files.

ISMA compared its DRM specification to secure sockets layer (SSL) and HTTPS, specifications that provide security for documents sent over the Web.

The new DRM specification builds on ISMA's own 1.0 specification and on the National Institute of Standards & Technology's (NIST) 128-bit AES encryption standard. ISMA said that meant it was free of intellectual property constraints.

One industry expert said ISMA's work would advance DRM technology for streaming media, but only incrementally.

"I see it as another step toward more interoperability in DRM," said Rob Koenen, president of the MPEG-4 Industry Forum. "But that's a difficult problem to solve. There are many little steps to be taken on the road to more interoperable DRM and agreeing on encryption is only one of them."

More thorny issues that awaited resolution included the establishment of a standard way of evaluating and managing "trust," or the degree to which a certain player or device that is downloading media is considered secure. That will require some kind of entity that certifies players and devices after a high degree of technical analysis, Koenen said.

Ongoing work under the MPEG 21 banner is addressing some of these problems, including the establishment of an XML-based language for DRM rules.

The ISMA invited "technical members of the security or content protection community" to apply for a review copy of the specification on the consortium's Web site.