Research On Quantum Private Query Protocols And Security Issues

With the development of quantum computing and quantum information,quantum private query(QPQ)has become an important branch of quantum cryptography application.Since the first QPQ protocol(GLM protocol)was proposed in 2008,many QPQ protocols have emerged,and the ones based on quantum oblivious key transfer have become the mainstream due to their prac-ticality.Although the main obstacles in the protocols have been eliminated,some issues still deserve further study.Therefore,the research on the more secure QPQ protocols based on quantum oblivious key transfer and security issues has become a hot topic in the field of quantum cryptography application.The contributions of this thesis are mainly on the design and analysis of the more secure QPQ protocols based on quantum oblivious key transfer for some issues faced in the development of QPQ.The details are as follows.(1)For the issue of channel noise,by analyzing the influence of collective noise caused by the environment on the security of oblivious key transfer,we propose a QPQ protocol based on single-qubit measurement universally appli-cable against collective noise,and analyze its security.It encodes key bits in noiseless subspace and thus can resist collective noise,reduces the errors in-troduced in the transmission and requires only single-qubit measurement.The security analysis shows that the special coding method improves the uncertainty of Alice’s results based on quantum randomness and reduces the probability of dishonest Bob’s attack,which ensures excellent user privacy.(2)For the issue of user privacy,we propose a QPQ protocol using one quantum state to enhance user privacy,and analyze its security.Based on a decoherence free state,it achieves superior user privacy and can resist collective noise.The security analysis shows that the probability of dishonest Bob’s attack is further reduced,which enhances the user privacy.Using only one quantum state reduces the communication complexity.It is universally applicable against collective noise,which can reduce the errors introduced in the transmission.(3)For the issue of transmission error handling,by analyzing the influ-ence of external attack on the security of oblivious key transfer based on en-tanglement swapping,we propose a one-way QPQ protocol based on iterative programming for real-time error detection,and analyze its security.Real-time error detection is achieved through iterative programming.The errors include the ones caused by the channel noise or external attack or both,so that the pro-tocol can resist the channel noise and external attack.The security analysis shows that Alice’s honest test is implemented while detecting external attack,and there is no need to detect Bob’s cheating which ensures excellent user pri-vacy.One-way quantum communication reduces the communication complex-ity and protects from Trojan horse attack,which strengthens the security.(4)To extend the point-to-point QPQ,we propose a network private query protocol with quantum third parties.It extends point-to-point quantum private query to multi-user quantum network private query,and establishes a new query mechanism with quantum third parties.A bilayer network topology,as well as the corresponding network private query protocol,ensure a rapid and secure network private query.Under the protection of the multi-qubit GHZ state’s quantum correlation,the privacy of Alice and Bob is protected from the third parties’fake entangled attack and external attack,and they cannot obtain the privacy of each other by taking quantum memory attack.This protocol has potential to advance the study of QPQ protocols.