Semiquantum private comparison of size relationship based on d-level single-particle states

In this paper, we propose a novel semiquantum private comparison (SQPC) protocol of the size relationship based on dlevel single-particle states. This protocol can compare the size relationship of different privacy messages from two classical users with the help of a semi-honest third party (TP), who is permitted to misbehave on her own, but cannot be in collusion with anyone else. The correctness analysis shows that this protocol can gain correct comparison results. The security analysis results reveal that this protocol can resist some famous outside attacks and participant attacks. This protocol only adopts d-level single-particle states as the initial quantum resource, only requires the TP to perform d-level single-particle measurements, and makes the accurate comparison results inaccessible to the TP. Compared with the only existing SQPC protocol of size relationship (Quantum Inf. Process. 20, 124 (2021)), the proposed protocol has advantages in experimental preparation of initial quantum resource, TP's experimental measurements, and TP's knowledge about the comparison results.