Information access control method and device, and write-once medium

摘要

An access management system such as an AACS is used to protect highly confidential information recorded in a write-once medium. To first prepare a title key file for encryption by the AACS, title keys (or Kts) are prepared as many as the number of rules of a usage rule file (ST300 to ST306). The plurality of title keys prepared in this manner are written in the title key file (ST308). The title keys written in this title key file are appropriately used to encrypt contents, and the encrypted contents are then recorded in the write-once medium.