Described herewith is an optical disk manufacturing apparatus for reading recorded digital data from an optical disk, comprising an encryption unit (22, 23) for encrypting entered digital data according to a plurality of key information; an optical disk substrate manufacturing unit 2 for manufacturing...http://www.google.com.au/patents/US7035181?utm_source=gb-gplus-sharePatent US7035181 - Apparatus and associated methodology of imparting content protection to optically recorded data for secure reproduction
