A semi-quantum private comparison protocol based on hybrid quantum states
Yan Hou, Jian Li, S. Liu +1 more
Abstract Semi-quantum private comparison (SQPC) is a quantum cryptographic protocol that allows two classical participants to securely determine whether their private inputs are equal, with the assistance of a semi-honest third party possessing full quantum capabilities. However, most existing SQPC protocols suffer from low qubit efficiency and high implementation costs, primarily due to their reliance on pre-shared keys and complex entangled state preparations. To address these limitations, we propose a novel SQPC protocol based on hybrid quantum states, which integrates Bell states and single-qubit states within a circular transmission architecture. The protocol eliminates the requirement for pre-shared keys and reduces consumption of quantum resources by introducing randomness in the placement of quantum states. Security analysis demonstrates that the proposed protocol is robust against measure–resend attacks, entanglement measurement attacks and internal threats from dishonest participants. Furthermore, performance evaluation shows that the proposed protocol achieves a high qubit efficiency, quantified as η = n 10 n + 1 , where n is the number of bits compared. This efficiency surpasses that of several previously proposed SQPC protocols.
Laser Physics Letters•Nov 1, 2025•1 citation