Patent ID: 8041039

Claim:
A secret communications system comprising: a center node; and a plurality of remote nodes, each of which is connected to the center node through an optical transmission line, wherein a plurality of channels are set between the center node and each remote node, wherein the plurality of channels include a first channel used for transmission of a quantum signal and a second channel used for data communication, wherein the center node comprises: a first switch for switching the first channel to connect to a selected one of the remote nodes; a second switch for switching the second channel to connect to a selected one of the remote nodes; and a controller for independently controlling the first switch and the second switch so that they are connected to different remote nodes selected from the plurality of remote nodes, so as to perform transmission of a quantum signal, generation of shared random number through the second channel based on data obtained by detecting the quantum signal through the first channel and/or cryptographic communication using cryptographic key extracted from the shared random number.