DTCP prevents mass copying, allows streaming

DTCP is a little-understood content-protection technology that is increasingly being used by content providers.

The ink on the U.S. Supreme Court's ruling last week against peer-to-peer file sharing services may barely be dry, but the PC industry is ready to help the entertainment industry secure the future distribution of premium content over the Internet thanks to a technology known as DTCP.

Digital rights management (DRM) technologies are helping entertainment companies take their first steps in enabling legal downloads of music and movies, just as the widespread use of peer-to-peer networks has fallen with legal actions taken by organizations such as the Recording Industry Association of America.

Consumer advocates are watching this evolution closely, concerned that the entertainment industry will take advantage of the advent of DRM technology to set policies that greatly restrict what users can do with content they purchase. Some fear that the ability to make copies of DVDs or digital files could be erased, forcing users to purchase additional copies of the same song for use on their PCs and iPods, for example.

A group of companies, including Intel, Sony, Toshiba, Matsushita Electric Industrial (Panasonic), and Hitachi, developed DTCP over IP (Digital Transmission Content Protection over Internet Protocol) several years ago as a way of mollifying consumer concerns about the use of premium content downloaded from the Internet. The last two generations of Intel's chipsets, the 915 and 945 chipsets, support DTCP, a protocol that identifies copy policies set by the content provider and decides whether that data can be transferred over a network to other devices in accordance with those policies.

DTCP prevents users from making multiple copies of protected content and sharing it over the Internet, but it allows a user to stream that content over home networks to various devices, said Stephen Balogh, a business development manager in Intel's corporate technology group. The technology does not actually encrypt the content itself, it instead protects that content during transmission from one device to another, he said.

For example, a fan of TV channel HBO's mob drama The Sopranos might record the forthcoming season premiere on their DVRs (digital video recorders) but would prefer to watch the episode in a different room. DTCP would allow the user to stream that content to a PC or digital television in another room, but prevent that content from being physically transferred to those devices.

In order to use DTCP technology, content providers must allow users to copy their content at least once in accordance with guidelines established by Intel and other companies, Balogh said. However, they can set policies that prevent additional copies, he said.

DTCP works by determining the copy protection status of a file, and demanding an authentication key from the intended recipient of that copy. So, the content could be copied from a user's set-top box to a DVR, but not copied again from the DVR to a PC if the content provider wishes to prevent that, Balogh said.

"DTCP doesn't dictate what you can or can't do with that piece of content," Balogh said. The content provider determines what users can and can't do with the content, and DTCP just recognizes those copy policies, he said.

While some users might protest that the copy-once scheme is a step back from current usage rights, Balogh believes the entertainment industry is actually disappointed that even one copy can be made. "If we had just invented a technology like DTCP and let it loose, everything would be marked copy-never," he said.

Intel and the other companies insisted that users be allowed to make that one copy, and the content providers fell into line because of the pressing need for content protection technologies, Balogh said

Content owners and device manufacturers must support DTCP technology for the whole process to work, Balogh said. Older content stored on PCs or content not recognized by DTCP technology will not be protected, and could be freely copied, even if a user's PC supports DTCP, he said.

Movies downloaded from Movielink will support DTCP later this year, said Elana Altshulter, a company spokeswoman. The movie download service currently uses DRM technology from Microsoft and RealNetworks Inc. to prevent users from copying the movies they download from Movielink's Web site to DVDs or hard drives, she said.

Movielink users pay between US$1.99 and US$4.99 to download full-length movies to their PCs for 30 days. Once a user starts the movie, they have 24 hours to watch it, Altshulter said. Microsoft or Real's DRM ensure the files expire within the stated limits, but DTCP would allow users to stream the Movielink films to a larger digital display, for example.

Despite the fact that DTCP will allow users to stream their content around the home, many users still will not be satisfied with technologies that restrict their freedom to use and copy their CDs and DVDs. Balogh understands those concerns, but believes that minimal copy protection schemes are better than the alternatives.

"Content protection solutions or DRM should enable new, flexible media experiences that strike a balance between consumer expectations and rights holder's interests," Balogh said.

Eventually, Intel and Advanced Micro Devices Inc. plan to build hardware-based security into their products that could support advanced DRM schemes. It's unclear at this point what exactly those technologies will allow users and content providers to do, since neither company is saying much about it. But the gradual evolution of DRM technology will be watched closely by legions of passionate computer users.

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Tom Krazit

IDG News Service
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