Reports that HD DVD rips have appeared on BitTorrent networks is the first challenge to AACS (Advanced Access Content System), the copy protection system used by both HD DVD and Blu-ray. Serenity was the first movie to appear, and has been followed by Pitch Black, The Chronicles of Riddick and Batman Begins.
The news will have triggered the first Revocation call in the format’s history. So what does the Revocation process involve and what will be the consequences?
Mark Knox, spokesman for the HD DVD promotional group explains: “Batman Begins goes out on HD DVD. A 14-year-old in Finland cracks the key to his HD DVD deck and he then puts HD video out onto the net. Immediately, Warner realizes this has happened. Warner engineers determine what the key is, and then send an email to the AACS licensing Association, who call up the key block engineer, who in turn tags the key as bad. A new key update is then sent to all the disc replicators. When that Finnish teenager goes into a store a few weeks later and buys a new HD DVD release, he’ll find that his machine won’t play it. His key registers as bad because the keyblock is part of the content of his new disc. He’ll still be able to play his Batman Begins disc, though.”
The ability to keyblock HD disc formats has been part of their copy protection design since the very beginning. It was San Francisco’s Cryptography Research Inc which developed the concept of self-protecting digital content – meaning that the mechanism that protects the content is itself part of the content – and it’s this that forms the foundation of the AACS copy protection system. AACS enables every frame of a pirated HD movie to be examined and the specific ID key for that player to be identified, even if the footage has been re-encoded to analogue video, MPEG or DiVX.