DIGITAL INFORMATION PROVING AND ACQUIRING SYSTEM AND DIGITAL INFORMATION DISTRIBUTING METHOD

摘要

PROBLEM TO BE SOLVED: To use data at a plurality of places without damaging the convenience of data dealing, and to prevent the illegal use of data by a person other than a legal user. SOLUTION: When a card 1 is inserted, user terminal equipment 2 transmits selection information and an instructed license condition from an input part 12 and a public key acquired from the card 1. A center device 3 decides whether or not the received selection information can be distributed under the instructed license condition, and when it is decided that the distribution is possible, the center device 3 encrypts and transmits the information by using the received public key. At the time of using encrypted information, the user terminal equipment 2 decodes the encrypted information by using a secret key acquired from the card 1. Thus, it is possible to use digital information by copying data without damaging the convenience of data dealing between the user terminal equipment using different cards having the same key or user terminal equipment exclusive for reproduction. Also, it is possible to prevent the illegal use of data by any person other than a legal user who owns the card 1 having the same key.