HDCP master-key leaks, possible to make unrestricted Blu-Ray recorders

Engadget reports that the master key that controls HDCP, the anti-copying system used to restrict the outputs of Blu-Ray boxes, set-top boxes, and many game systems, have been compromised and published. With these keys, knowledgeable users can make their own “source” and “sink” keys for devices that permit copying at full resolution — which means that you should be able to create a hard-drive-based recorder that you can plug into your Blu-Ray player and record shows in real-time. This player would be immune to “revocation” (part of the HDCP specification that allows a cartel of Hollywood studios to remotely disable devices so they won’t interoperate with compromised systems — essentially, the ability to reach into your living room and shut down your equipment).

Apparently there is a cryptographic argument that says that these master keys could be derived from any fifty HDCP devices, but my money is on a plain old leak. Cryptographic keys are tiny pieces of information, and this sort of key would be known to a large number of people: a small, easily conveyed secret known to a lot of people is pretty much doomed.

HDCP ‘master key’ supposedly released, unlocks HDTV copy protection permanently

(Image: DRM Inlet, a Creative Commons Attribution (2.0) image from jamescridland’s photostream)