Measurement device independent quantum key distribution system and method based on W state

Abstract

The invention discloses a measurement device independent quantum key distribution system and method based on a W state. The system comprises four quantum terminal units and one quantum terminal unit.Pulsed lasers of the four quantum terminal units transmit laser of a specified wavelength, the phase of [0, 2 phi] is randomly modulated by a phase modulator, horizontal, vertical, +45-degree or -45-degree polarization is randomly loaded by a polarization controller, a decoy state or a signal state is marked by a strength modulator, and finally, the laser is attenuated by an adjustable attenuatorto an average photon number theoretically calculated and optimized and then transmitted to a quantum relay unit. The quantum relay unit performs W state projection measurement on signals transmitted through a quantum channel; according to the response of a detector, the quantum relay unit publishes the measurement result, and two are randomly selected from the four quantum terminal units to publish quantum states; if the quantum states of the two are anti-dependent, the data is discarded; and if the quantum states of the two are dependent, the remaining two are bit-flipped to obtain a shared password. The system and the method for quantum key distribution using the W state have better adaptability to the environment, and are low in cost by adopting mature basic linear optical components.

Description

technical field [0001] The present invention relates to the technical field of quantum information and optical communication, in particular to a measurement device-independent quantum key distribution system and method based on a W state. Background technique [0002] Since Bennett and Brassard proposed the first Quantum Key Distribution (Quantum Key Distribution, QKD) "BB84" in 1984, it has benefited from the combination of channels (optical fibers) and devices (such as beam splitters, avalanche photodiodes, APDs) in optical transmission networks. With continuous progress, QKD has become the closest practical technology in the field of quantum information. QKD can realize that in the presence of an eavesdropper, the legitimate communication parties (usually referred to as Alice and Bob) share a theoretically absolutely secure quantum key. Combined with "One Time Pad (OTP)" technology, Alice and Bob can achieve absolutely secure communication through quantum keys. [0003]...

AI Technical Summary

Problems solved by technology

[0027] At present, a quantum cryptography conference based on GHZ state using polarization state coding is proposed, mainly for quantum key distribution among the three parties, and W state analysis using time-bin coding device and proposed a multi-party quantum key distribution protocol based on the device, but the coding efficiency of the system and the utilization efficiency of system components are low

Images