Multi-party Quantum Private Comparison Based on the Entanglement Swapping of d-level Cat States and d-level Bell states

TL;DR

This paper introduces a new multi-party quantum private comparison protocol using entanglement swapping of d-level states, ensuring security against various attacks without relying on QKD.

Contribution

It proposes a novel protocol that allows multiple parties to compare private secrets securely with a semi-honest third party, based on entanglement swapping of d-level states.

Findings

Protocol withstands outside and participant attacks.

Semi-honest third party learns only the comparison result.

No QKD methods needed for key security.

Abstract

In this paper, a novel multi-party quantum private comparison (MQPC) protocol with a semi-honest third party (TP) is proposed based on the entanglement swapping of d-level cat states and d-level Bell states. Here, TP is allowed to misbehave on his own but will not conspire with any party. In our protocol, n parties employ unitary operations to encode their private secrets and can compare the equality of their private secrets within one time execution of the protocol. Our protocol can withstand both the outside attacks and the participant attacks on the condition that none of the QKD methods is adopted to generate keys for security. One party cannot obtain other parties' secrets except for the case that their secrets are identical. The semi-honest TP cannot learn any information about these parties' secrets except the end comparison result on whether all private secrets from n parties are equal.