An efficient semi-quantum private comparison without pre-shared keys

Semi-quantum private comparison protocol permits two classical participants to compare the equality of their private information with the help of a semi-honest third party without disclosing privacy. An innovative semi-quantum private comparison protocol based on maximally entangled Greenberger–Horne–Zeilinger-type states has been discussed. The proposed protocol is efficient and without the pre-shared keys. Next, the security analysis guarantees the presented protocol is asymptotically secure against the outsider and the insider attacks. Moreover, the qubit efficiency of the presented protocol is 3.125%. The efficiency comparison shows that it improves the efficiency by 125% for the literature without pre-shared keys.