| In today’s information age,network information security is concerned all over the world.As a signature method of electronic messages,digital signature can be used to identify the integrity and correctness of digital information.It has been widely used in various communication scenarios such as e-commerce and e-government.Encryption algorithms in classical digital signatures are generally implemented based on computational complexity.With the rapid development of computer science and quantum computing,the security of classical digital signatures is increasingly threatened.On the other hand,the security of quantum digital signature(QDS)is based on quantum mechanics and has unconditional security theoretically.At present,most of the theoretical researches on quantum digital signature protocol assume that the state preparation is perfect,but in reality,due to the defects of physical devices,state preparation flaws will be introduced,which will affect the practical security of the system.By referring to the idea of loss-tolerant Quantum Key Distribution(QKD)protocol proposed by Tamaki K et al in 2014,we introduced the loss-tolerant idea into the theoretical model of QDS protocol,and carried out relevant security analysis and numerical simulation.The results show that the loss-tolerant QDS scheme has good robustness to the state preparation flaws.With the rapid development of quantum information technology,the repetition frequency of QDS system keeps increasing,which makes the system transmission period much shorter than the detector dead time,and the dead time effect will limit the generation rate of initial key to a certain extent.In addition,single-photon avalanche detectors commonly used today have after pulse effects,which can significantly affect the gain and bit error rate at the measurement end in high-speed QDS systems.In this paper,the dead time and after pulse effect are considered for the first time in highspeed QDS system.The effects of the dead time and after pulse effect on the performance of QDS system are systematically discussed by constructing relevant mathematical model and theoretical analysis.This paper mainly focuses on the practical security of QDS system.The influence of state preparation flaws is considered for the source end,and the influence of dead time and after pulse effect is considered for the detector end,which makes QDS system closer to the practical application. |
