Patent ID: 7188245

Claim:
A contents transmission/reception system, comprising: a transmission device; and at least one reception device that receives contents from the transmission device; wherein the transmission device and the reception device are physically connected to an identical local area network, or are not physically connected to the identical local area network but virtually existing in an identical sub-net, the transmission device has: an authentication and key exchange processing unit configured to carry out an authentication and key exchange processing with a reception device that made a contents transmission request; a device identification information transmission request unit configured to transmit a device identification information request to the reception device, such that the reception device transmits a device identification information; a device identification information registration unit configured to register the device identification information transmitted from the reception device by an upper level protocol above a network layer; a device identification information search unit configured to search out the device identification information corresponding to an IP (Internet Protocol) address of the reception device by a protocol on the network layer, from a network to which the reception device is connected: a comparison judgement unit configured to judge whether the device identification information searched out by the device identification information search unit and the device identification information registered by the device identification information registration unit coincide or not; and a distribution condition determination unit configured to change a distribution condition for contents to be transmitted to the reception device that made the contents transmission request, according to a judgement result obtained by the comparison judgement unit; and the reception device has: a contents transmission request unit configured to make the contents transmission request to the transmission device; and a device identification information transmission unit configured to transmit the device identification information of the reception device to the transmission device, upon receiving the device identification information request from the transmission device.