Research On Information Reconciliation For Satellite-ground QKD

Quantum information processing or quantum information science is an amalgamation of quantum physics and information science.Its unconditional security features make it become a new communication technology.Nowadays,the distance of quantum key distribution in the fiber channel has already reached the theoretical limit and is difficult to implement long-distance quantum key distribution.Considering the high stability and low loss of single photon transported in the atmosphere,the satellite-ground quantum key distribution of free-space is the most feasible solution for secure communications on a global scale.Due to the imperfection of the quantum equipment and the noise in the channel,the raw key will have some bit error rate and cannot be used for secure communications.To solve this problem,we use the information reconciliation to extract raw key,and then the key on both sides of communication are identical.This paper first introduces the knowledge of traditional cryptography and quantum cryptography.The classical encryption can only be proven secure based on the presumed diffi culty of a mathematical problem.With the development of quantum computing,this highly complex encryption method is dangerous.Fortunately,the security of the quantum key is ensured by the basic law of quantum mechanics,and use it for communication is unconditional security.The second chapter mainly introduces the principle of quantum key distribution and protocol.The third chapter introduces the post-processing of satellite-ground quantum key distribution,namely,authentication ?error checking?information reconciliation and privacy amplification.In the fourth chapter,some information conciliation algorithms in quantum key distribution are analyzed and studied,and a new data coordination model based on Turbo code is proposed.Finally,through the model simulation,we get the information reconciliation efficiency based on Turbo code.The fifth chapter carries on the optimization and simulation to Turbo,and increases its error correction efficiency by 15%.To test and verify the feasibility of the model,we implement satellite-ground quantum key distribution simulation experiments and respectively use the Cascade and Turbo for information reconciliation.In the experiment,the key error rate is 3.43%.Experimental results show,information reconciliation based on the Cascade has a larger final keygeneration rate.Compared with Cascade,Turbo can make the final key generation increased by 8%.The experiment proves the feasibility of its application in the future experimental satellites of quantum science.The sixth chapter is the summary of the thesis,including the concept of quantum key distribution?principles and protocols ?data post-processing.Then,we summarize the whole process of research.An efficient,real-time information reconciliation scheme is the key to satelliteground quantum key distribution,which will promote the establishment of a worldwide satelliteground quantum communication networks.