The Research On Twin-Field Quantum Key Distribution

Based on the principle of quantum physics,quantum communication can guarantee the absolute security of information transmission in theory.In the process of communication,the key information is loaded on the quantum state and transmitted to the information receiver through the quantum channel.After receiving the information,the two sides extract the security key according to the agreed protocol,and then realize the transmission of information.In the actual experiment process,quantum communication often faces various security problems,which mainly focus on the light source and detection part of the system.The decoy state protocol solves the security problem caused by multi photon of light source,and the MDI QKD protocol solves the security problem of imperfect detector.The development of quantum communication is very fast,and the technology is more and more mature.Quantum communication has gradually developed from the laboratory system with low coding efficiency and short transmission distance to the communication system with high coding rate and long-distance transmission.The twin-field quantum key distribution protocol proposed in 2018 can effectively break through the key capacity limit that traditional point-to-point QKD can't break through,and has high practicability.In this paper,we systematically study the twin-field quantum key distribution protocol.In the first two chapters of this paper,we summarize the development of classical cryptography and quantum cryptography,which leads to the key part of quantum cryptography-quantum key distribution.Then,the basic physical knowledge involved in quantum communication is briefly introduced.Then,the key protocol principle and security key calculation method in quantum communication are studied in detail.At the same time,the key modules of quantum communication system are introduced in detail.Based on the previous theoretical research,this paper studies the double field quantum key distribution in the third and fourth chapters.In the third chapter,the principle of TF QKD protocol is introduced,and its security is analyzed in detail.Specifically,the ideal TF QKD protocol is based on the first-order interference of two light fields with the same random phase.It can achieve long-distance quantum key distribution and effectively break through the quantum key capacity limit.Even after being attacked by aggregation separation for phase post-processing,it still has good key performance.At the same time,the improved protocol based on TF QKD protocol is compared and analyzed.In Chapter 4,the TF QKD scheme of HSPS source is proposed.HSPS is used to replace WCS with high dark count rate,and decoy state is introduced to resist PNS attack.The scheme can effectively improve the key transmission distance.With the improvement of detection efficiency,the key rate performance of the scheme is improved significantly.