Practical quantum private query of blocks based on the two-dimensional QKD system

Quantum private query of blocks (QPQB) allow user to obtain meaningful multiple consecutive bits in one query, which has certain advantages in improving communication efficiency and protecting user privacy. However, previous QPQB protocols generally show poor practicability for the use of high-dimensional quantum system (which is difficult to implement) or the ignorance of error correction (as a result, user may pay for a false database item). To solve this problem, we proposed a new fault-tolerant quantum protocol for private query of blocks based on the two-dimensional quantum system, by using a special reorder-shift-addition technique. This technology can not only compress user’s additional information obtained in error correction, but also can reduce the user’s advantage obtained from the alignment of the key bits in bitwise adding, solving an inherent security problem in postprocessing. Moreover, our protocol is loss tolerant and can resist the quantum memory attack.