New flexible quantum private query protocol against rotation noise.

The quantum privacy query protocol (QPQ) is faced with low query efficiency, transmission channel noise, and low transmission efficiency problems. The quantum-privacy query protocol proposed by us aims to achieve a better quantum-privacy block query effect and has the function of anti-rotation noise. To solve the collective rotation noise in the transmission channel, we propose a one-way QPQ protocol based on four particles. The four-particle states { ϕ 0 , ϕ 1 , ϕ 0 ′ , ϕ 1 ′ } can be entangled by two Bell states { Φ + , Ψ - } with anti-noise properties. In general, the unidirectional quantum privacy query has more advantages than a bidirectional quantum privacy query. Besides, the post-processing scheme Yang et al. (Quantum Inf Process 15(9):38333840, 2016) can not only protect the parity result of the random key but also guarantee the security of the protocol. In the security analysis, we prove the security of the user and database. [ABSTRACT FROM AUTHOR]