Research On Practical Quantum Cryptographic Protocol

Quantum communication has the advantages of fast transmission speed,high security,large storage capacity,etc.,thus attracting wide attention from domestic and foreign researchers.Unlike classical cryptography,it breaks the traditional communication method and integrates quantum mechanics with classical cryptography.So it plays an important role in ensuring the security of information transmission.And its security is guaranteed by the basic principles of quantum mechanics.In theory,it can achieve unconditional security,regardless of the attacker's mathematical computing power.Its rise has had a very important impact on the field of information security technology.Over 30 years of quantum cryptography research,a variety of cryptographic protocols and communication schemes have been produced.Such as quantum key distribution,quantum key agreement,quantum secret sharing,deterministic secure quantum communication,quantum bit commitment,quantum coin tossing,quantum secure direct communication,quantum private query,quantum digital signature,etc.Quantum cryptography can ensure the security of the key in an ideal condition.In fact,the quantum cryptography system cannot reach the ideal condition,such as the imperfections of various equipment and transmission loss.Eavesdroppers use these non-ideal loopholes to steal keys,but they will not be discovered by legitimate users.With the development of science and technology,the defects of quantum devices and various attack methods will emerge in endlessly.Therefore,it is particularly important to design a more secure and practical quantum cryptographic protocol.Quantum cryptography can ensure the security of the key in an ideal condition.In fact,the quantum cryptography system cannot reach the ideal condition,such as the imperfections of various equipment and transmission loss.Eavesdroppers use these non-ideal loopholes to steal keys,but they will not be discovered by legitimate users.With the development of technology,the defects of quantum devices and various attack methods will emerge in endlessly,such as side channel attacks.Therefore,it is particularly important to design a more secure and practical quantum cryptographic protocol.Focusing on the device defects of quantum key agreement,deterministic secure direct communication,and quantum secret sharing in actual communication,we learn from the methods of semi-device-independent quantum key distribution and measurement-device-independent quantum key distribution.We have made practical designs and improvements for several quantum cryptographic protocols.For quantum key agreement,we proposed a semi-device-independent quantum key agreement protocol,a measurement device-independent quantum key agreement protocol,and a high-capacity measurement device independent quantum key agreement protocol,respectively.For deterministic secure direct communication,we proposed a measurement device-independent deterministic secure quantum communication protocol and a high-capacity measurement-device-independent deterministic secure quantum communication protocol,respectively.In addition,we analyzed the security for the quantum secret sharing protocol proposed in the article [Gao et al.,Sci.Chin.Phys.Mech.Astron.63(12),120311(2020)] and found that the protocol is flawed.Our main contributions lie in the design of practical quantum cryptographic schemes by using semi-device-independent and measurement-device-independent techniques to solve practical problems.(1)We present a semi-device-independent quantum key agreement protocol to prevent the unreliability of the preparation device.Here,we worked on the QKA protocol based on BB84.And the state preparation device has no detailed characterization but the only assumption is that its Hilbert space dimension is known.The security of the protocol is ensured by the device-independent dimension witness for independent preparation device.(2)We present a measurement-device-independent quantum key agreement protocol in order to remove the detector attacks.Using the BB84 model and the ATVY state,adjust the quantum state coefficients and the number of coin flips to reduce the maximum deception probability of the two parties and achieve the fairness of the agreement.(3)We present the first high-capacity measurement-device-independent quantum key agreement protocol by optimizing the proposed measurement-device-independent quantum key agreement protocol.Using polarization and spatial-mode degrees of freedom of photons,it not only removes the detector attacks but also increases single photons' channel capacity.Simultaneously,both two parties' maximum cheating probabilities can also be reduced by adjusting the values of the parameters.Furthermore,we derive the conditions for achieving fair QKA under a coherent attack.(4)We present a measurement-device-independent deterministic secure quantum communication protocol in order to eliminate the detector attacks.And we use the BB84 communication model and the ATVY states.The maximum deception probability of the eavesdropper can be reduced by adjusting the coefficient value to better prevent external eavesdropping.(5)We present a new high-capacity measurement-device-independent deterministic secure quantum communication protocol by optimizing the proposed measurement-device-independent deterministic secure quantum communication protocol.Using the polarization of photons and the degree of freedom of spatial mode,it has the advantages of eliminating the attack of the detector and the capacity of a single photon channel.At the same time,the maximum cheating probability of eavesdroppers can be reduced by cleverly adjusting parameters to better prevent external eavesdropping.(6)We reexamine the deterministic measurement-device-independent quantum secret sharing protocol for the article [Gao et al.,Sci.Chin.Phys.Mech.Astron.63(12),120311(2020)].Here we point out that a dishonest participant can obtain the secret message alone without being detected,which shows that the MDI-QSS protocol is insecure against dishonest participants.