SYSTEM AND METHOD FOR PROCESSING INFORMATION, INFORMATION PROCESSOR AND PROGRAM PROVIDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To actualize a system by which a ciphered contents key is selected selectively from header information and the contents key is obtained in a device reproducing contents. SOLUTION: A contents key used to decipher ciphered contents is ciphered with different ciphering processing keys and stored as the header information of the contents. One of contents keys is a piece of data ciphered with a cipher key provided by an effective key block(EKB) having a data structure where keys are made to correspond to nodes on a path from the root of a key distribution tree structure to its leaf and which data structure can be deciphered only by a specific device, and another contents key is a piece of data ciphered with a key inherent to a storage device, and a contents reproduction execution device selects the cipher key data selectively and performs processing.