QUANTUM ENCRYPTION COMMUNICATION EQUIPMENT AND PRIVATE KEY GENERATING METHOD USING QUANTUM ENCRYPTION COMMUNICATION EQUIPMENT

摘要

PROBLEM TO BE SOLVED: To provide a system having a long transmission distance in a differential phase shift quantum key delivery system. SOLUTION: By performing quantum encryption by using light (signal and idler) sent out from a first light source generating an entanglement photon pair provided in the middle of a first device (Alice) and a third device (Charlie) and light sent out from a second light source generating an entanglement photon pair provided in the middle of the third device and a second device (Bob), a delivery distance to transmit sufficient light can be prolonged as a total. Charlie communicates the fact that photons are detected continuously in one photon detector and the time or the fact that the photons are alternately detected in two photon detectors and the time to Alice and Bob. Alice and Bob transmit and receive the time at which they respectively detect the photons to/from each other. Alice and Bob generate a key bit by using the event that Charlie continuously detects the photons from time information and the event that both of Alice and Bob detect the photons corresponding to that. COPYRIGHT: (C)2006,JPO&NCIPI