Information processing system and method

摘要

An information processing system and method are disclosed in which information processing is performed in a highly efficient manner using an enabling key block (EKB) on the basis of a tree structure including category subtrees. A key tree is formed so as to include a plurality of subtrees serving as category trees categorized in accordance with categories and managed by category entities. An EKB includes data produced by selecting a path in a tree and encrypting a higher-level key in the selected path using a lower-level key in the selected path. The resultant EKB is provided to a device. Distribution of EKB's is managed on the basis of an EKB type definition list representing the correspondence between an EKB type identifier and one or more identification data identifying one or more category trees that can process an EKB of an EKB type specified by the EKB type identifier.