Calder’s Corner: HDCP


By Calder Phillips-Grafflin

HDCP, the encryption system used by Blu-Ray, HDMI, DisplayPort, and DVI to ‘protect’ digital content—long considered one of the strongest forms of Digital Rights Management (DRM)—has finally fallen with the release of the “master key” to the system. The key, posted anonymously on the internet, would allow anyone to build a device capable of authenticating HDCP encryption, which would allow for perfect copying of copy-protected digital media.

HDCP was developed in 2000 by Intel to provide a standard mechanism of copy protection for the variety of digital video interfaces used in the computer and home theater market. The system uses a combination of key exchange, handshaking, and strong encryption to restrict digital content to approved devices, which can be a problem for legitimate users who try to combine HDCP-compliant and non-compliant hardware in their systems.

Additionally, HDCP is designed to prevent or restrict the use of digital content over analog links like VGA or Component video, as these links would allow for easy copying.

Vulnerabilities in HDCP have been known for almost a decade; theoretical vulnerabilities were first noted in 2001, and special devices known as “HDCP strippers” have been available for the past several years.

But until now, there were no proven attacks against the entire system.

Since the release of the key this past week, Intel has confirmed its “master key” status, which opens up a market for devices to circumvent HDCP. These devices won’t be legal in the U.S. because of the Digital Millennium Copyright Act (DMCA), but that won’t stop the production and distribution of them over the Internet.

So, for those of you with old TV and monitors that don’t support HDCP, it means that a new set of adapters will be available to add HDCP support to your device. For media pirates: better copies of Blu-Ray movies and HDTV shows. And for Linux users and do-it-yourself electronics hobbyists: a new generation of open-source home theater components.


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