Patent ID: 8134937

Claim:
A plurality of node devices in a content data storing and sharing system, the content data storing and sharing system comprising the plurality of node devices including an administrative node device, the plurality of node devices and the administrative node device being connected through a network, the plurality of node devices storing content data to be shared by the plurality of node devices and the administrative node device administrating the content data to be shared by the plurality of node devices, wherein: at least one node device in the plurality of node devices comprises: a broadcast channel determination unit that randomly determines a broadcast channel, the content data to be stored being broadcasted in the broadcast channel; a content receiving unit that receives the content data broadcasted in the broadcast channel determined by the broadcast channel determination unit; a storage determining unit that randomly determines whether unit content data corresponding to a predetermined amount of the content data is to be stored in the node device, in response to receiving the unit content data which is broadcasted in the broadcast channel determined by the broadcast channel determination unit; a storing unit that stores the unit content data in response to determining that the unit content data is to be stored; and a registration message transmission unit that sends a registration message, informing that the received unit content data is stored in the node device, to the administrative node device in response to storing the unit content data.