Multi-Party Quantum Private Comparison with Qudit Shifting Operation

Abstract

In this paper, a multi-party quantum private comparison (MQPC) protocol is proposed based on the qudit shifting operation. The semi-honest third party (TP) prepares the initial particles and sends them to the first user. Then, each of n users encodes his private integers on the travelling particles with the qudit shifting operations and transmits them to the next user. Finally, the travelling particles are transmitted back to TP. The equality of the private integers from n users can be determined within one time execution of the protocol. It is verified that the proposed protocol is secure against both the outside attack and the participant attack. One user cannot obtain other users’ private integers except for the case that their private integers are same. TP cannot know the private integers from n users except their comparison result.