Following the wide spread publicity of the AACS hack, especially with working out the HD DVD processing key, the AACS LA has started sending out Cease and Desist letters to various blog sites as well as the search giant Google for publishing the key to simply linking to the Doom9 threads about the crack.  These sites have been threatened with legal action if they do not comply.  Unlike going after websites publishing DeCSS software or software that uses DeCSS, the processing key is only useful for sophisticated programmers capable of writing software to rip and decrypt the discs, much like how a blue-print drawing of a door key is not sufficient to unlock a door without an engineer first making a physical key based on it. 

Unfortunately for the AACS, it looks like it is going to be quite tricky for Google to take on this measure, considering the 1,000's of websites this processing key has been published on and more showing up all the time.  Going by the letter, Google had a week from the letter's date of April 17th to comply and despite that period now being long overdue, Google still indexes 1,000's of website site links containing the key as well as the links indicated for removal in the letter. 

One thing that makes the HD DVD decryption key more attractive than the DeCSS key for DVD is the ability to create software to play HD DVDs with high definition on systems lacking HDCP support, something even commerical DVD playback software will not allow.  At present, while most consumers have a monitor well capable of showing at least 720p at its native resolution, the lack of HDCP support forces the user to either use an analogue connection or be forced to watch the picture in a greatly reduced resolution. 

Thanks to Aktiv8 for letting us know about this news, who added the following:

Apparently there is a key which will enable bypassing of the HD-DVD DRM to allow users to play their titles on their Linux boxes.

The key in question is (edited out) and is an HD-DVD decryption key that was leaked on April 30, 2007. The source of the leak is unclear.

No doubt it is of interest to cryptographic researchers, as it can be used to play a protected HD-DVD movie in Linux, bypassing the normal DRM.

The key will also allow for programs analagous to DeCSS for DVDs.

Just google the Key to get a lot of hits!

Further information can be read here on this ZD Net blog.  The Cease and Desist letter issued by AACS to Google can be viewed on this Chilling Effects notice page.