The Research On The Practical Security Of Quantum Key Distribution System

The harmony and prosperity of modern society is undoubtedly based on the information security.If there is no guarantee of information security,everything is empty,including huge data,the t.hird industrial revolution and the fourth indus-trial revolution proposed in many countries around the world.Data security in a modern communication system is guaranteed by classical cryptosystems,such as R-SA[1]?DES[2]and so on.The idea of protecting data with classical cryptosys-tems may be difficult to accomplish,since the present of the Shor[3]algorithm and the great development of quantum computer.As the development of quantum information,perfect safe one-time pad cryptosystem is realize.d.We can protect da-ta primarily through quantum cryptosystem in the near future.Currently,due to limitation of scientific technology,quantum direct communication is hard to real-ize in quanta communication field.However,quantum key distribution technique has been much riper.Quantum key distribution is studied earliest in quantum cryptogra-phy.Moreover,the theory and experimental results about quantum key distribution are also the most.Unconditionally secure cryptosystem can be realized the.oretically by combining quantum key distribution with one-time pad,which is guaranteed by quantum mechanism.However,the original research focused on proving the unconditional security of the quantum key distribution by theory,which ignored many issue.s existing in the practical application.In recent years,with the commercialization of quantum key distribution,many security problems to be solved exist in practice.This pa-per systematically discusses some safety performance problems for key components of the mainstream system,and specifically explore the QBER is affected by the phase drift induced by ambient temperature difference in key devices such as faraday mir-ror,phase modulator and optical fiber.Moreover,we identified the relation parameter boundary occurring in faraday mirror and phase modulator.We put forward that temperature difference can affect both optical fiber length and fiber phase coeffi-cient.The quantitative study shows that the system is very sensitive to the influence of temperature difference,and a cyclical temperature change of phase drift just needs 0.05?,which is increased nearly 20 times compared to the current scope requires that have been considered.Because arm difference reduction of current interference ring and further control of temperature difference ask for the rigorous experimental conditions,improving the safety performance of practical communication system and further reducing the deviation caused by faraday mirror and phase modulator is beneficial to allay some problems about phase drift induced by temperature differ-ence.In addition,for the two mentioned in the article compare common quantum key distribution system,we according to the physical security conditions of cryptosys-tem and analysis of asymmetric double Mach-Zender interferometer phase coding system is superior to the " plug and play" system.