Efficient quantum private comparison protocol based on the entanglement swapping between four-qubit cluster state and extended Bell state

Abstract

Quantum private comparison (QPC) protocol can guarantee the two participants to compare the equality of their private information without leaking them. Based on the entanglement swapping between the four-qubit cluster state and extended Bell state, an efficient QPC protocol has been proposed. Three bits of the secret inputs have been compared in each comparison time, which improves the efficiency compared with the previous QPC protocols’ one or two bits. Then, based on a random sequence pre-shared between the two participants, the semi-honest third party can only execute the protocol’s process without obtaining the information of the participants’ secrets and comparison results. Last, various kinds of attacks have been analyzed, which show that the proposed protocol is secure against the outside and participants attacks.