We have to read the HDCP and AACS implementation details to even begin to understand what those fellows are doing. The HDCP thing is available on their website. It is a pdf file. Don't know about AACS.They are using a software DVD player (WinDVD, PowerDVD etc.) to watch their hidef-movie. While it is playing, they are looking for various keys in memory. Once they have the keys they can decrypt and rip the movie. Since the HDCP+AACS cp scheme is such that individual keys can be revoked in future releases, a generic circumvention scheme has not been discovered till now. If a particular player is compromised, all future movies note the key as blacklisted and refuse to play on that device.
