Quantum network coding is expected to enable multiple quantum data packets to be fused before the transmission via the bottleneck channel in order to improve the transmission efficiency and the total throughput of quantum networks. Although several quantum network coding schemes have been constructed, they are unable to meet the practical application requirements due to the fact that they lack a complete security solution. To tackle this issue, a practical secure quantum network coding scheme is constructed. Compared with existing methods, the proposed quantum network coding scheme is more practical and most importantly it can provide complete security against both information leakage and pollution attacks, which greatly contributes to global quantum communication networks.

Quantum Anonymous Private Information Retrieval (QAPIR) allows a user to retrieve an item from a database anonymously thus achieving better user privacy. Recently, Khanet al. proposed the first QAPIR protocol [IEEE Trans. Commun. 70(6), 4026-4037 (2022)] which is the only known QAPIR protocol. However, a symbol coincidence error occurs when the main ingredients are combined to form this QAPIR protocol. Furthermore, it requires perfect (n+1)-partited-dimensional Greenberger-Horne-Zeilinger (GHZ) states to be pre-shared among the nodes whereD≥NandNis the size of the database. However, the difficulties in implementing the preparation of high-dimensional GHZ states and the quantum-computing-based queries under current technologies lead to the impracticability of this QAPIR protocol due to the extremely high dimensionalities of GHZ states and oracle operations when large databases are involved. To address these issues, we first point out the symbol coincidence error in Khanet al.’s QAPIR protocol and then give an improvement on it. Finally, we propose a practical QAPIR protocol based on quantum key distribution. We analyze its performance under certain types of noise. We also prove the security of our QAPIR protocol in an active adversary scenario where active dishonest users and database owner are taken into account. Compared with Khanet al.’s protocol, our protocol is easier to implement under current technologies, and can work over the noisy quantum channel.1It provides a practical way for the design of QAPIR protocols.