Study On Round Robin Differential Phase Shift Quantum Key Distribution Protocol And Its Application

In general,the generation of secure key of QKD protocol needs monitoring eavesdropper's interference.When error rate is greater than a certain threshold,a legal user discards the key generated by the key distribution process.However,RRDPS-QKD protocol does not need to monitor eavesdroppers' interference and it has higher no ise tolerance and has become a hotspot in current QKD protocol research.The thesis mainly studies RRDPS-QKD protocol and its application,that is,the improvement of RRDPS-QKD protocol and its application to quantum secret sharing(QSS).The specific works of the thesis are as follows:(1)Taking the advantage of the probability of single-photon pulse in the heraled single-photon source(HSPS)higher than that of weaker coherent source(WCS)and detector decoy(DD)method can achieve similar functions of photon number resolving(PNR)detector,the thesis proposes a RRDPS-QKD protocol based on HSPS and DD.The HSPS pulse sequence generated by laser at the Alice is phase encoded and sent to the receiver Bob.The HSPS pulse sequence comes first through an intensity modulator IM with transmission ratio ?,and then carries out MZI interference measurement,and then both parties in the communication obtain the final key through a series of post-processing operations.The thesis deduces the formula of its key generation rate and conducts related numerical analysis.The results show that the key generation rate of RRDPS-QKD protocol based on HSPS and DD is larger than that of RRDPS-QKD protocol based on WCS and DD when pulse sequence length L is smal.(2)Using decoy state technique,a x: y splitter BS is added to the sender to propose a quantum secret sharing(QSS)scheme based on decoy BB84 protocol.The thesis elaborates basic principle of the scheme in detail,deduces the formula of its key generation rate and conducts related numerical analysis.The results show that the performance of the QSS scheme based on the decoy BB84 protocol is indeed not as good as that of decoy state BB84 protocol,and the splitter BS ratio is preferably maintained at 2:8.(3)Furthermore,based on the high noise tolerance of RRDPS-QKD protocol,the thesis replaces decoy BB84 protocol in point(2)with RRDPS-QKD protocol,and presents a QSS scheme based on RRDPS-QKD protocol.The thesis elaborates the basic p rinciple of the scheme and carries out relevant theoretical derivation and numerical analysis.The results show that the farthest transmission distance of QSS scheme based on RRDPS-QKD protocol is 50 km and the QSS scheme based on decoy state BB84 protocol can not generate secure key when system error probability is 3.5%,and the splitter BS ratio is preferably maintained at 1:9.