Quantum key distribution method and apparatus

Abstract

The embodiment of the invention relates to the field of quantum key distribution, in particular, to a quantum key distribution method and apparatus for accurately determining a first phase difference.According to the embodiment of the invention, a second local oscillation optical signal is divided into M third local oscillation optical signals and N fourth local oscillation optical signals; the phase of each of the N fourth local oscillation optical signals is deflected at a preset angle to obtain N fifth local oscillator optical signals; for each of the M third local oscillation optical signals, coherent detection is carried out on the third local oscillation optical signal and a first reference optical signal to obtain a first coherent detection result; for each of the N fifth local oscillator optical signals, coherent detection is carried out on the fifth local oscillation optical signal and a second reference optical signal to obtain a second coherent detection result; and thus afirst phase difference is determined based on the at least one first coherent detection result and at least one second coherent detection result accurately.

Description

technical field [0001] Embodiments of the present invention relate to the field of quantum key distribution, and in particular, to a quantum key distribution method and device. Background technique [0002] For a one-way Quantum Key Distribution (Quantum Key Distribution, referred to as QKD) system, its implementation is by encoding a set of random numbers on the quantum state of the quantum optical signal at the sending end, which is transmitted by the quantum channel after being transmitted. Receiver detection at the receiving end, and then a series of post-processing processes such as data comparison and negotiation between the sending end and the receiving end through classic channels, finally allowing both parties to share a set of secure random number keys. The two parties in the communication use the obtained security key to encrypt the communication content with a one-time pad encryption method to realize unconditionally secure and confidential communication. Contin...

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Problems solved by technology

[0004] However, the above scheme is still in the laboratory environment, and the continuous working time of the system is short, and the impact on the actual working environment is not considered enough

In a real environment, the phase difference between the local oscillator optical signal 107 and the reference optical signal 102 is determined by the DSP 109. Usually, there are many interference factors, and the estimation error is relatively large, and the estimation error will also increase with the local oscillator optical signal. Random and unpredictable changes due to changes in strength, which will affect the generation rate of quantum keys

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