Quantum private information retrieval with lattice-based access authentication

Most quantum key distribution (QKD)-based quantum private information retrieval (QPIR) protocols cannot resist denial-of-service (DoS) attacks. Furthermore, these protocols generally involve issues with an unspecified error rate threshold. To address these issues, we propose the QPIR protocol based on two lattice-based post-quantum algorithms, i.e., CRYSTALS-Dilithium for digital signatures and CRYSTALS-KYBER for key establishment. Specifically, in the quantum secure direct communication network, part of the key establishment process is replaced by the verification of signatures encoded in quantum states. This approach not only achieves access authentication but also effectively resists DoS attacks. We provide a detailed security analysis of our protocol. Furthermore, we provide a method for selecting three parameters \(m\), \(d\) and \(\theta \) according to security requirements, especially for the security against DoS attacks, thus offering greater flexibility in our protocol.