said by karlmarx 
:The processing key is the Bob of the Alice and Bob crypto schema. In order to encrypt a disc, you need two things, a public key (alice) and a private key (alice). For Bob to decrypt something from alice, he needs to know Alice's public key (i.e. the HD-DVD). That's what the studios are looking to 'blacklist', so if a player is compromised, they could make the new dvd's NOT work with that player. Thus, every HD-DVD and Blu-Ray contains a section of 'disabled' players (public keys).
If what he said is correct, he's found alice's PRIVATE key. With that key, you don't need to care about the public key. EVERY DVD uses the private key, so you can decrypt everything.
I don't claim to be a crytologist, but I think I'm missing something from your explanation. In asymmetrical encryption, there are two keps. Private and public. Something is encrypted with one, and then decrypted with the other. The key that did the original encryption can't also be used to decrypt the cyphertext.
