Research On Private Query Protocol Based On Oblivious Quantum Key Distribution

Oblivious quantum key distribution(OQKD)is a fundamental and important security technology in quantum cryptography.It is an oblivious key distribution method that has the advantages of easy implementation,low overhead,and high security.Quantum private query is a new query scheme that mutually penetrates the symmetrical privacy information retrieval problem and quantum cryptography.It can also guarantee database security and prevent users from illegally stealing database information.Based on the application prospects of quantum private query,this paper chooses to conduct in-depth research and analysis on OQKD-based quantum private query,and proposes two OQKD-based private query protocols,mainly including flexible nearest private query and resistance to collective-dephasing noise.In terms of research,the main research results are as follows:(1)Flexible quantum protocol for nearest private query based on OQKD is proposed.The protocol is composed of two participants:the data owner Bob and the user Alice.Suppose that the data owner Bob has a private data set D,and the user Alice has private data x.Under the premise of protecting their privacy,after the quantum query protocol,Alice obtains the element_ix closest to x in Bob's privacy sequence.In the protocol,by adding parameters to the prepared quantum state,the average number of key bits obtained by the user can be located at any fixed value for any database size by adjusting the parameters,which solves the problem of users when the database capacity is too large.It improves the controllability and flexibility of the protocol.(2)Noise is an uncontrollable interference factor in quantum communication,especially for applications of quantum private queries.Aiming at the problem of noise,a quantum private query protocol that can resist collective-dephasing noise is proposed.The protocol uses logic Bell as a quantum resource for quantum oblivious key distribution,and the logical Bell state and its entanglement in noise are used to resist collective-dephasing noise.At the same time,the protocol can also detect third-party eavesdropping behavior to ensure the security of the protocol.