Content distribution system and content distribution method

A contents charges settlement method based on tickets, comprising:

• a step for transmitting a contents purchase request from a user device to a ticket issuing server;
• a step at the ticket issuing server for executing billing processing based on contents purchase request data from the user device, and issuing tickets storing a charges reception entity identifier as contents charges information accompanying processing for purchasing of contents, and allocated charges data with regard to said charges reception entity, under the conditions the billing processing has been completed;
• a step at the user device for receiving said ticket;
• a step at a user device authentication server, which is configured as one of said charges reception entity, for executing conversion from an encrypted contents key which is undecryptable with a stored key in said user device to an encrypted contents key which is decryptable with a stored key in said user device by key-changing processing, under the conditions that said ticket has been received from said user device;
• and
• a step at a ticket cashing server for executing charges settlement processing based on the received ticket, according to receipt of a ticket from said charges reception entity.

A program providing medium for providing a computer program for executing contents charges settlement processing based on tickets on a computer system, said computer program comprising:

• a step for receiving tickets storing a charges reception entity identifier as contents charges information accompanying processing for purchasing of contents, and allocated charges data with regard to said charges reception entity;
• a step for executing signature verification processing of the electronic signature of said ticket issuing server contained in the received ticket;
• a step for executing processing based on the receipt of said ticket under the conditions that conformation is made that there is no tampering with data by verification of the signature;
• a step for executing a charges settlement request based on said ticket.

A contents distribution system having a log managing configuration, comprising:

• a shop server for receiving contents purchase requests from a user device, and transmitting sales confirmation data to the user device;
• a user device for transmitting contents purchase request data to the shop server and executing contents purchase requesting processing based on procedures using a public key certificate of the user device having validity set, and also receiving said sales confirmation data and generating and storing a purchase log based on the received sales confirmation data;
• and
• a log collection server for receiving an updating request for a public key certificate of said user device based on receipt of said purchase log, and transmitting an updated public key certificate of the user device issued by a public key certificate authority to the user device.

A contents distribution method having a log managing configuration, comprising:

• a step for transmitting contents purchase request data from a user device to a shop server and executing contents purchase requesting processing based on procedures using a public key certificate having validity set;
• a step at the shop server for receiving a contents purchase request from the user device, and transmitting sales confirmation data to the user device;
• a step at the user device for receiving said sales confirmation data and generating a purchase log based on the received sales confirmation data;
• and
• a step at a log collection server for receiving an updating request for a public key certificate of said user device based on receipt of said purchase log, and transmitting an updated public key certificate of the user device issued by a public key certificate authority to the user device.

A program providing medium for providing a computer program for executing contents distribution management on a computer system, said computer program comprising:

• a step for receiving a purchase log which a user device generates according to contents purchased by said user device;
• a step for executing verification of said purchase log;
• and
• a step for accepting a public key certificate updating request from said user device under the conditions that the authority of the received log has been confirmed by the verification of said purchase log, obtaining the updated public key certificate, and transmitting to said user device.

A data communication method containing attributes confirmation processing, comprising:

• an attributes information obtaining step for, between entities executing data communication, obtaining attributes information set at an entity which is the other party of communication from a public key certificate or attributes certificate of an entity which is the other party of communication;
• and
• an attributes confirmation step for executing attributes confirmation based on the attributes information obtained in said attributes information obtaining step;
• wherein confirmation of the validity of attributes in said attributes confirmation processing step is the conditions for executing the next process.