Research On And Implementation Of Plug-play Reference-Frame-Independent And Measurement Device Independent Quantum Key Distribution System

As known,the security of classical public key cryptosystems lies in the mathematical complexity,and its basic hypothesis is that computers cannot solve those problems in efficient time.But,the advent of quantum computers may threaten the security of classical public key cryptosystems,for example,Shor's algorithm can efficiently solve factorization.Different from the classical cryptosystems,quantum cryptosystems based on quantum key distribution(QKD)can,in theory,achieve the unconditionally secure transmission of information.However,due to the limitation of current technologies and the imperfections of actual devices,there is a gap between the actual QKD system and the ideal protocol,which leaves a spae for attackers to exploit.Fortunately,researchers have given their solutions to most attacks accordingly,such as the measurement-device-independent quantum key distribution(MDI-QKD)which eliminates all attacks on the receiver side channel.The MDIQKD system achieves greater security,but the experimental system is complex and requires a phase and polarization reference system calibration system.Reference-frame-independent quantum key distribution(RFI-QKD)protocol can ensure the key robustness under the condition of reference misalignment,and eliminate the need for complex calibration systems.This paper proposes a novel implementation scheme of MDI-QKD system around the RFIQKD protocol,and extends the two-party QKD based on the RFI-QKD protocol to the fouruser QKD quantum communication system.The main contents are as follows:Firstly,the current development situation of quantum communication is introduced,the development history of QKD protocol based on reference frame independence is introduced in detail,and the future development trend of QKD protocol is represented.Secondly,some theoretical knowledge about quantum communication is given.From the Shannon entropy and classically mutual information,its quantum generalizations,von Neumann entropy and Holevo bound,are gradually introduced,which paves the way for the calculation of information quantity and key rate in this thesis.Aiming at the imperfections of quantum devices,the security of untrustworthy light sources under BB84 protocol is studied,and the corresponding solutions are given.Finally,the principles of the RFI-QKD protocol and the MDI-QKD protocol are given,and a brief security analysis is given.Thirdly,a novel implementation method of MDI-QKD system is proposed: Plug-play reference-frame-independent and measurement-device-independent QKD system(abbreviated as Plug-play RFI-MDI-QKD system).This system is based on the RFI-MDIQKD protocol,and adopts Plug-play structure,and it can eliminate all attacks on the detector side channel,without complicated phase and polarization reference system calibration system,which simplifies the experimental device and saves the cost.Meanwhile,the system only uses a single light source,which effectively solves the security vulnerabilities caused by the inconsistency of multiple laser sources.The simulation results show that the longest communication distance can reach 248 km even though the relative phase angle ? has a great fluctuation,which strongly promotes the development of the practical quantum secure communication system.Fourthly,a novel QKD protocol for multi-user communication is proposed.Based on the Wstate multi-user reference-frame-independent and measurement-device-independent QKD protocol(abbreviated as the W-state RFI-MDI-QKD protocol),the corresponding experimental schematic diagram is given.According to the W-state RFI-MDI-QKD protocol,besides preventing the attack on the detector side channel,the complex calibration system with strict alignment of the reference frame is avoided.In addition,the security of four-party RFI-MDI-QKD protocol is analyzed,and the effect of relative phase angle ? on the key rate C and the amount of information obtained by the eavesdropper Eve is analyzed.The results show that even if the relative phase ? has a large variance,the longest communication distance can reach 148 km.This work has taken an important step towards the multi-party quantum communication network.Finally,We summarize the whole thesis and look forward to the next step.