CONTENT USE SYSTEM AND ADVERTISEMENT CONTENT USE METHOD

摘要

The anonymity of the user of contents can be ensured while enabling the user to play a content on a viewing terminal for playing a content. The content use system includes a communication terminal, a viewing terminal, and a license server. The communication terminal generates an electronic ticket by giving a group signature to the license information obtained from the license server.The viewing terminal verifies the group signature of the electronic ticket obtained from the communication terminal and thereafter transmits the electronic ticket to the license server. The license server judges whether or not the received electronic ticket can be used. If it judges that the electronic ticket can be used, it gives a license of the content to the viewing terminal. The viewing terminal decrypts the encrypted content by using the decryption key obtained according to the license and plays the decrypted content.