Quantum Private Comparison Without Entanglement
In this paper,a quantum private comparison protocol based on d dimensional single-particle states is proposed. In the protocol,a semi-honest third party transfers a sequence of n particles to one participant w ho encodes n secret keys by performing n local unitary operations. Then these particles are sent to the other participant w ho also by the same w ay encodes n secret keys and returns these particles back to the semi-honest party. Finally after the participants broadcast the results of encrypting their secrets w ith secret keys,the semi-honest third party can help the tw o participants compare the size relationships of their n pair corresponding secrets w ithout disclosing them to any other people. In addition,the security of the protocol is also discussed in detail. It is show n that the protocol is secure in theory. Moreover,since only single-particle states are used,as compared w ith other quantum private comparison protocols,the presented protocol is more feasible under the current technical conditions.