Patent ID: 8600051

Claim:
A distribution method of a quantum cryptography key, the method comprising: generating, by a transmitter, a composite-quantum-system including first and second sub-quantum-systems; transmitting, by the transmitter, the second sub-quantum-system to a receiver that is connected to the transmitter through a quantum channel; measuring, by the receiver, the second sub-quantum-system; measuring, by the transmitter, the composite-quantum-system that is disturbed according to the measurement performed by the receiver; generating, by the transmitter and the receiver, the quantum cryptography key based on results of the measurements performed by the transmitter and the receiver, wherein the first sub-quantum-system is confined within the transmitter, and the composite-quantum-system is not determined at the outside of the transmitter without disturbing the composite-quantum-system, and wherein the generating of the quantum cryptography key comprises: announcing, by the transmitter and the receiver, information on the measurement results to each other through a classical channel connecting the transmitter and the receiver, the information including a part of the measurement results obtained by the transmitter and the receiver; and comparing the announced information to generate the quantum cryptography key.