Measure-Resend Semi-Quantum Private Comparison Scheme Using GHZ Class States

Quantum private comparison is an important topic in quantum cryptography. Recently, the idea of semi-quantumness has been often used in designing private comparison protocol, which allows some of the participants to remain classical. In this paper, we propose a semi quantum private comparison scheme based on GreenbergeHorne-Zeilinger (GHZ) class states, which allows two classical participants to compare the equality of their private secret with the help of a quantum third party (server). In the proposed protocol, server is semi-honest who will follow the protocol honestly, but he may try to learn additional information from the protocol execution. The classical participants' activities are restricted to either measuring a quantum state or reflecting it in the classical basis{|0>,|1>}. In addition, security and efficiency of the proposed schemes have been discussed.