Research On Efficient Quantum Communication Protocols And Their Attack And Defense Strategies

Quantum communication is one of the most promising applications of quantum information science.It utilizes quantum effects to offer unconditionally secure mes-sage transmission.Ever since the first example of quantum communication,i.e.,quan-tum key distribution(QKD),was invented by Bennett and Brassard in 1984,various variant protocols were proposed and many of these protocols have been demonstrated.However,existing protocols are faced with problems of low efficiency,security threats,etc.For example,since QKD wastes a lot of photons arising from basis reconciliation,it is thus plagued by low efficiency.And because the photon is transferred back and forth between the legitimate users in quantum secure direct communication(QSDC),deterministic secure quantum communication(DSQC),quantum secret sharing(QSS)protocols,these protocols are facing the threats of Trojan horse attacks.To solve above problems,we have done the following tree aspects of work.First,based on chaotic cryptography and middleware technology,we propose an efficient and universal QKD protocol that can be directly deployed on top of any exist-ing QKD system without modifying the underlying QKD protocol and optical platform.It initially takes the bit string generated by the QKD system as input,periodically up-dates the chaotic system,and efficiently outputs the bit sequences.Theoretical analysis and simulation results demonstrate that our protocol can efficiently increase the bit rate of the QKD system as well as securely generate bit sequences with perfect statistical properties.Compared with existing methods,our protocol is more efficient and uni-versal,it can be rapidly deployed on the QKD system to increase the bit rate when the QKD system becomes the bottleneck of its communication system.Second,based on data block transmission and order rearrangement technologies,we propose a deterministic secure quantum communication(DSQC)protocol.It u-tilizes a set of single d-level systems as message carriers,which are used to directly encode the secret message in one communication process.Theoretical analysis shows that these employed technologies guarantee the security,and the use of a higher di-mensional quantum system makes our protocol achieve higher security and efficiency.Since only quantum memory is required for implementation,our protocol is feasible with current technologies.Furthermore,Trojan horse attack(THA)is taken into ac-count in our protocol.We give a THA model and show that THA significantly increases the multi-photon rate and can thus be detected.Finally,we find out that existing single photon based quantum secret sharing pro-tocols cannot resist Trojan horse attack.We first give a modified Trojan horse attack strategy and show that the eavesdropper can obtain any player's private data and can reconstruct the secret message without leaving any trace.Then we design a quantum memory based defense strategy and evaluate its resistance.The evaluation results show that the eavesdropper's attack significantly increases the quantum bit error rate and can thus be detected.Moreover,several suggested rules are given aiming at assisting de-signers of new quantum secret sharing protocols.