The Research On Quantum Secure Communication Protocols:Design And Analysis

Quantum information theory is the creature in a new cross-discipline which combines quantum mechanics with classical information theory,such as computer science,physics and mathematics.Employing the properties of quantum mechanism,quantum information can open up an information age with faster,better and more secure communication methods.Quantum communication,especially quantum cryptography,which guarantees unconditional security of the information by quantum mechanics,is regarded as the most promising application in quantum information.In recent years,since quantum cryptography has been paid more and more attention by the governments,military establishments,research institutions and industrial departments,it has rapidly evolved with impressive results,both in the theoretical foundation and experimental implementations,and is ready to go into a practical and engineering phase.However,there are still many problems left for further investigations in quantum secure communications.Up to now,only a few quantum key distribution protocols are proved be secure and the proof method cannot be directly applied to other protocols.Moreover,the deviation between the security proof and the practical system can be exploited by eavesdropper.It is worthy to further study how to devise new quantum communication protocols and prove their security,and how to ensure the security of practical quantum cryptography systems.The contributions of this dissertation are mainly on the design and analysis of quantum secure communication protocols,including quantum teleportation(QT),quantum secure direct communication(QSDC),quantum private comparison(QPC)and quantum private query(QPQ).The details are as follows:With respect to the design,we propose a QT protocol to teleport an arbitrary n-qubit state via GHZ-like channels with a strict proof through mathematical induction;a QT protocol to teleport a multi-qubit entangled state via a four-qubit cluster state by introducing CNOT gate and ancillary qubits;an efficient quantum dialogue protocol with authentication by using GHZ states and six-qubit entangled states with no unitary operations;a QPC protocol without any unitary operations by using a six-qubit entangled state;a counterfactual three-party QPQ protocol.All these protocols are analyzed from the view of security in detail.As for the security analysis,the security of some quantum cryptography protocols are analyzed,and several effective attack strategies are presented.Some improvements are also given.With the proposed attacks,a dishonest user can obtain the other's private without being detected in a two-party QPC protocol;a dishonest third party can obtain both users' private without being detected in a QPC protocol based on single photons and collective detection which is suspective to Trojan-horse attacks;a dishonest user can obtain the secrets of dadabase in a couterfactual QPQ protocol.These simple and effective attacks are helpful and instrctive for later research on designing new protocols with high security.Besides,we propose a control mode modification with Hadamard operation in QSDC protocols of Bell type,which strengthens such protocols against both Pavi?i?'s and Wójcik's attack theoretically and practically.