http://www.counterpane.com/crypto-gram-9911.html#DVDEncryptionBroken
Schneier thinks that the key is at some point available in software, which
is not how I understood it to work. However, even if the key is never in
memory the system is critically flawed, since the DVD data must pass
through memory in order to be decoded.
Security through obscurity: it just doesn't work (for long).
John