Key-Rate Bound of a Semi-Quantum Protocol Using an Entropic Uncertainty Relation

TL;DR

This paper introduces a novel proof technique for semi-quantum key distribution that uses entropic uncertainty relations to achieve better key-rate bounds, enhancing security analysis.

Contribution

It presents a new entropic uncertainty-based method for bounding adversary information, improving key-rate bounds over previous noise-statistics-based approaches.

Findings

More optimistic key-rate bounds achieved.

Reduced measurement data requirements.

Potential applicability to other protocols.

Abstract

In this paper we present a new proof technique for semi-quantum key distribution protocols which makes use of a quantum entropic uncertainty relation to bound an adversary's information. Our new technique provides a more optimistic key-rate bound than previous work relying only on noise statistics (as opposed to using additional mismatched measurements which increase the noise tolerance of this protocol, but at the cost of requiring four times the amount of measurement data). Our new technique may hold application in the proof of security of other semi-quantum protocols or protocols relying on two-way quantum communication.