| Information security has always been a matter of concern,it involves personal privacy,business secrets and national defense and other aspects.Cryptography is a science for the confidentiality of information,the most basic task is to provide security by the encryption method.After World War Ⅱ,people pay more attention to the research of cryptography.The classic cryptography is divided into public-key cryptosystem and private-key cryptosystem.The security of the public-key cryptosystem is not strictly proven.As the development of quantum computers,it will bring a serious challenge to public-key cryptosystem’s security.The private-key cryptosystem has strong anti－computing ability and absolute security in theory,but the security of key distribution is a major problem.The emergence of quantum key distribution technology solves the problem of key distribution.Its security is based on the basic theorem in quantum mechanics field such as quantum no-cloning theorem,the Heisenberg Uncertainty principle and measurement-collapse theory.Bennett and Brassard first proposed the BB84 protocol in 1984,its theoretical security is proved later.Although the theoretical security of the QKD protocol is proved,the actual experimental devices inevitably have imperfection of the light sources,communication channels and detectors,etc.This article mainly finished the following works:This paper first introduces the development of cryptography and the research of quantum key distribution.Then the most famous BB84 protocol of quantum key dis-tribution technology is introduced,and the protocol security and practical security of quantum key distribution technology are discussed respectively.Then the correspond-ing solution is given,i.e.,the newly proposed reference-frame-independent and the measurement-device-independent quantum key distribution system(RFI-MDI-QKD).Finally,a novel quantum tomographic method is proposed to estimate the asymptotic security key rate in the RFI-MDI-QKD protocol.We propose a new method to estimate the asymptotic security key rate in the RFI-MDI-QKD protocol.According to the numerical simulation of the asymptotic secure key rate,we prove that tomographic method is equivalent to conventional RFI MDI method in the ideal situation and has a slightly higher asymptotic secure key rate as the transmission distance increases when the reference frame is uncalibrated. |
