Content distribution system, content distribution method, and client terminal

A content distribution method for distributing contents over a network including a distribution server for giving permission to reproduce contents and client terminals for reproducing contents, the content distribution method comprising:

• transmitting trial permission information to a first client terminal from a second client terminal;
• generating a digital signature based on the trial permission information transmitted to the first client terminal;
• generating a request comprising the digital signature and the trial permission information;
• transmitting the request from the first client terminal to the distribution server;
• authenticating the digital signature in the request on the distribution server;
• transmitting content to the first client terminal from the distribution server based on the trial permission information;
• and reproducing the content on the first client terminal.

A content sharing system for sharing contents over a network, comprising:

• client terminals within one network, wherein a first client terminal can access content information stored by a second client terminal on the network;
• and
• a server for sending contents to the client terminals;
• wherein the second client terminal transmits a selection of a user preferred for content trial from a list of communicable users to the first client terminal;
• wherein the first client terminal transmits user information to the second client terminal;
• wherein the second client terminal transmits streaming data and contents ID corresponding to the streaming data to the first client terminal after receiving an acknowledge input of the user information;
• and
• wherein the first client terminal generates a digital signature based on the contents ID and a user ID stored by the first client terminal, generates a request comprising the digital signature and the contents ID, and sends the request to the server, and
• wherein the server receives the request, authenticates the digital signature in the request, and transmits content based on the contents ID to the first client terminal.

A content sharing method for sharing contents over a network including client terminals, the content sharing method comprising:

• displaying a list of communicable users managed by a connected user management unit on a display of the second client terminal, wherein a user of the second client terminal selects a user of the first client terminal for content trial from the list;
• transmitting a user information request to a first client terminal from a second client terminal;
• transmitting user information to the second client terminal from the first client terminal;
• transmitting streaming data and contents ID to the first client terminal from the second client terminal;
• generating a digital signature based on the contents ID and a user ID stored by the first client terminal;
• generating a request comprising the digital signature and the contents ID;
• transmitting the request to a server from the first client terminal;
• and
• transmitting content corresponding to the contents ID from the server to the first client terminal after authenticating the digital signature in the request.