Orthogonal-state-based and semi-quantum protocols for quantum private comparison in noisy environment

TL;DR

This paper introduces two novel quantum private comparison protocols, one avoiding conjugate coding and the other allowing classical users, with performance analysis under noisy conditions.

Contribution

The paper presents two new QPC protocols: one using only orthogonal states and another enabling classical user participation, enhancing practicality in noisy environments.

Findings

Protocols are robust under various noise models.

Orthogonal-state-based protocol eliminates conjugate coding.

Classical user participation is feasible in quantum comparison.

Abstract

Private comparison is a primitive for many cryptographic tasks, and recently several schemes for the quantum private comparison (QPC) have been proposed, where two users can compare the equality of their secrets with the help of a semi-honest third party (TP) without knowing each other's secret and without disclosing the same to the TP. In the exisiting schemes, secrecy is obtained by using conjugate coding, and considering all participants as quantum users who can perform measurement(s) and/or create states in basis other than computational basis. In contrast, here we propose two new protocols for QPC, first of which does not use conjugate coding (uses orthogonal states only) and the second one allows the users other than TP to be classical whose activities are restricted to either reflecting a quantum state or measuring it in computational basis. Further, the performance of the protocols is evaluated under various noise models.