Contents-distributing system and contents-distributing method

A contents-distributing system comprising a server and a client terminal that are communicable with each other,

• said client terminal including:
• contents-storing means for storing a plurality of contents;
• key file requesting means for sending a request of a key file to said server, said key file releasing restriction on utilization of one or more contents among said plurality of contents;
• key file storing means for storing the key file transmitted from said server;
• utilization restricting means for restricting the utilization of the contents stored in said contents-storing means;
• and
• utilization restriction releasing means for releasing the restriction on the utilization of the contents by said utilization restricting means under a predetermined condition in accordance with the key file stored in said key file storing means, and
• said server including:
• key file transmitting means for transmitting said key file to said client terminal in accordance with a request from said client terminal.

A server that is communicable with a client terminal, said server comprising:

• a database for storing a plurality of contents;
• contents-transmitting means for transmitting the contents in said database to said client terminal in accordance with a request from said client terminal;
• and
• key file transmitting means for transmitting a key file to said client terminal in accordance with a request from said client terminal, said key file releasing restriction on utilization of one or more contents among said plurality of stored contents.

A client terminal that is communicable with a server that stores a plurality of contents, said client terminal comprising:

• contents-obtaining means for sending a request of the contents to said server and for obtaining the requested contents from said server;
• key file obtaining means for sending a request of a key file to said server, said key file releasing restriction on utilization of said obtained contents, and for obtaining said requested key file from said server;
• utilization restricting means for restricting the utilization of said obtained contents;
• and
• utilization restriction releasing means for releasing the restriction on the utilization of the contents by said utilization restricting means in accordance with the obtained key file.

A client terminal that is communicable with a server, said client terminal comprising:

• contents-storing means for storing a plurality of contents;
• key file obtaining means for sending a request of a key file to said server, said key file releasing restriction on utilization of one or more contents among said plurality of stored contents, and for obtaining said requested key file from said server;
• utilization restricting means for restricting the utilization of said stored contents;
• and
• utilization restriction releasing means for releasing the restriction on the utilization of the contents by said utilization restricting means in accordance with the obtained key file.

A computer-readable recording medium containing a program applied to a client terminal that is communicable with a server that stores a plurality of contents, said program including:

• a contents-obtaining process for sending a request of one or more contents among said plurality of stored contents to said server and for obtaining the requested contents from said server;
• a key file obtaining process for sending a request of a key file to said server, said key file releasing restriction on utilization of said obtained contents, and for obtaining said requested key file from said server;
• a utilization restricting process for restricting the utilization of said obtained contents;
• and
• a utilization restriction releasing process for releasing the restriction on the utilization of the contents by said utilization restricting process in accordance with the obtained key file.

A computer-readable recording medium containing a program applied to a client terminal which is communicable with a server and which stores a plurality of contents, said program including:

• a key file obtaining process for sending a request of a key file to said server, said key file releasing restriction on utilization of one or more contents among said plurality of stored contents, and for obtaining said requested key file from said server;
• a utilization restricting process for restricting the utilization of said stored contents;
• and
• a utilization restriction releasing process for releasing the restriction on the utilization of the contents by said utilization restricting process in accordance with the obtained key file.