Research On Scheme Design And Security Analysis For Quantum Secure Communication

Quantum information science is an interdisciplinary of quantum mechanics and information science.Quantum secure communication is one of the most rapid development and promising applications in the fields of quantum information,as it can provide unconditional security.Among the quantum secure communication researches,quantum secure direct communication(QSDC)and quantum secure key distribution(QKD)are attractive topics.This thesis focuses on high information security and transmission efficiency of quantum secure communication.To achieve this arm,this thesis first designs several QSDC protocols and one QKD system,then analyzes their security.The main contributions of this thesis are as follows:1.A QSDC protocol is proposed based on the mixture of single photons and entangled pairs.The sender prepares single photons and entangled pairs,and divides entangled pairs particles into two sequences: one for the first security check and one for encoding.The sender encodes her classical message on the mixed quantum state sequence of the other sequence and single photon sequence.Then,some single photons used for security check are reinserted randomly into the encoded sequence,and the order of particles is rearranged to ensure to detect eavesdropper's attack.Research shows that the implementation process is simplified without complex unitary operation.The proposed protocol achieves 100% transmission efficiency,which is higher than most single source protocols.2.A QSDC protocol is proposed based on a class of three-particle W states in the non-symmetric channel.Using a class of three-particle W states,each quantum pair can carry 4.2 bits of classical message by employing different kinds of unitary transformation in the three-dimensional Hilbert space.In addition,a QSDC is proposed based on this quantum dense code.Research shows that the protocol can significantly improve the efficiency of information transmission compared with the general W states in symmetric channel ones.3.Two QSDC protocols are proposed based on three-particle Greenberger-Horne-Zeilinger(GHZ)states.The first protocol can greatly increase the number of error states under the attacks of eavesdropper by using single particle detection with the entanglement properties between the particles upon security check,and the detection probability is also increased.The error rate for eavesdropper is increased to 62.5%.Based on the first protocol,the second one,bidirectional QSDC scheme,is presented for star network.Under the control of the servers,each quantum pair can carry 4 bits of classical message by employing different kinds of unitary transformations between any two authenticated communication parties.And the passive attacks with unconsciously revealing information can be resisted4.A QSDC protocol with dynamic control code sequence is proposed.The initial sequence is obtained via chaotic systems.By grouping,the XOR operation and extracting,the control code sequence can be derived.A shift cycle algorithm is designed to enable the dynamic change of control code sequence.Research shows that transmission efficiency can reach 100% with high dynamics and security,and the availability ratio of particles is also improved.5.A continuous variable quantum key distribution(CVQKD)system based on real-time shot noise variance monitoring is designed.The active phase compensation method is proposed with scanning small amounts of phase points.Phase drift value can be obtained and satisfy precision requirements via the least squares algorithm.The simulations show that the performance of the method will not be affected by the positions of the phase points.It can improve the convergence rate of the phase drift value as the phase points are increased,and the effect of phase compensation is improved.The shot noise variance calibration technology is adopted in this system,and the real-time shot noise variance monitoring modules are added to the primary CVQKD system.The experimental result shows that this CVQKD system can defend the change of the shot noise variance under the local oscillator attacks from eavesdroppers,and subsequently improves the security.The security of the above schemes are analyzed and proved.