A system and method are realized which enables valid use of content by
preventing unauthorized use of content which is caused by rewriting
rights data. A structure is employed in which rights data including
use-restriction information on content and DRM data including an
encrypted content key are recorded in a digital data recording medium
(media), and in which an integrity check value (ICV) for the DRM data can
be stored in a recordable/playable area (protected area) by using only a
dedicated IC. EKB distribution is used to execute the tree-structure key
distribution to distribute keys for generating ICV-generation verifying
keys. In this structure, unauthorized use of content by rewriting of the
rights data is prevented.