Research On Practical Quantum Digital Signature And Quantum Key Distribution Protocols

With the development of science and technology,the cryptographic techniques used for secure communication are constantly updated.The privacy of current classical encryption algorithms depends on the computational complexity.However,with the continuous improvement of deciphering machine and decoding algorithms,the deciphering time is decreasing.Especially with the development of quantum computers,the security of public key encryption algorithms is threatened.Based on quantum information theory,the emergence of quantum key distribution(QKD)provides a new research direction,which can distribute secure key between two legitimate parties and monitor the behavior of eavesdroppers at well.To date,QKD has been quickly developed from theory to practical application,meanwhile,quantum digital signature(QDS)based on QKD has become a hot research topic.This thesis focuses on the QDS and measurement-device-independent QKD(MDI-QKD)protocols.The main research results are briefly described as follows:1.We propose a practical QDS scheme with configurable decoy states.In this scheme,the legitimate parties configure the number of decoy states to maximize the signature rate and/or simplify the experimental operation in practical scenarios.Considering different optical intrinsic errors,we investigate the performance of a typical QDS system in one and two decoy-state cases and give the corresponding guide to configure decoy states,which we expect would be valuable for researchers to design QDS systems.2.We investigate the MDI-QKD protocol with non-phase-randomized coherent state(NPRCS)sources.With the semi-definite programming method,we analyse the security of MDI-QKD based on NPRCS,which modulates different intensities in the test and key bases.Moreover,we investigate the performance of our protocol in practical scenarios,such as Trojan horse attack and asymmetric channels.Simulation results indicate that the MDI-QKD based on NPRCS protocol the peformance of MDI-QKD based on NPRCS can be significantly improved by modulating different intensities of coherent states in the key and test bases,which does not bring extra complexity for experimental researchers,and can be easily done by adding an intensity modulator.