Multi-party private size comparison protocol under the semi-quantum condition

Based on d-dimensional multiparticle maximal entangled states, a novel multi-party private comparison protocol under semi-quantum condition is proposed. With the help of a semi-honest quantum third party, N classical participants can determine the size relationship of their privacies while keeping them private in the devised protocol. Compared with some similar protocols, the presented protocol performs better in terms of security and qubit efficiency. In addition, the effectiveness and the correctness of our protocol are verified with some examples and proofs. By the decoy particles and the pre-shared keys, the presented protocol can defend against the internal and the external attacks.