sentences:  Hackers also claim to have found Device Keys
  (used to calculate the Processing Key) and a Host Private Key
  (a key signed by the AACS LA used for hand-shaking between host and HD drive; required for reading the Volume ID).The first unprotected HD movies were available soon afterwards.The processing key was widely published on the Internet after it was found and the AACS LA sent multiple DMCA takedown notices in the aim of censoring it.