KEY GENERATING METHOD, KEY GENERATING DEVICE, CONTENTS DISTRIBUTING DEVICE, TERMINAL DEVICE, AND PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide a distributing device provided with a contents key managing function which can arbitrarily constitute a various kinds of group hierarchies to the contents in a contents distributing system capable of group sales and group management, and a user terminal device. SOLUTION: A group decoding key for classifying a plurality of the contents into group units and for decoding the contents in group units is generated by using random numbers or the like. A contents decoding key for decoding the contents belonging to the groups is encrypted by using the group decoding key. The encrypted contents decoding key is added to the encrypted contents as decoding information and distributed to users. The users, who buy the group key, decode the decoded information by using the group key, and decode the encrypted contents by using the obtained contents decoding key. COPYRIGHT: (C)2005,JPO&NCIPI