| 摘要 |
An encrypted contents file contains use restriction information, and contents. The use restriction information corresponds to such an information capable of restricting a use of the contents when the contents are used. A Web server provides the encrypted contents file to a client, and thereafter, transmits use approval information outputted from a use approving unit to the client in response to a request issued from this client. The use approving unit approves the use of the contents under such a condition that the client has paid a consideration of the use of the contents, and changes a use restriction of the contents provided to the client, so that the client can use the contents. |
