| 摘要 |
PROBLEM TO BE SOLVED: To provide a key management system for determining an allotted key effectively and provide a recording unit, a reproducing unit, and a recording medium. SOLUTION: In a system made up of a recording unit for recording digital data of contents like a movie or a reproducing unit, and a recording medium, a media key used for recording or reproduction is enciphered by a plurality of device keys and stored in the recording medium. In the key management system, an arrangement, in which each node-annihilation pattern allotted to a node of a tree structure is arranged in a given regulation, is stored as header information along with an enciphered medium key in the recording medium. In the recording unit or the reproducing unit, an enciphered media key to be decoded by itself is specified from the plurality of enciphered media keys by analyzing the node-annihilation pattern sequentially. COPYRIGHT: (C)2003,JPO |
