Qutrit-based semi-quantum key distribution protocol

TL;DR

This paper proves the unconditional security of a semi-quantum key distribution protocol using qutrits, demonstrating improved noise tolerance and higher secret key rates compared to lower-dimensional protocols.

Contribution

It introduces a secure semi-quantum key distribution protocol based on 3-dimensional states and derives a key rate bound showing enhanced noise tolerance.

Findings

Higher secret key rate than 2-dimensional protocols

Increased noise tolerance with higher system dimension

Unconditional security proof for qutrit-based SQKD

Abstract

This article provides the unconditional security of a semi quantum key distribution (SQKD) protocol based on 3-dimensional quantum states. By deriving a lower bound for the key rate, in the asymptotic scenario, as a function of the quantum channel's noise, we find that this protocol has improved secret key rate with much more tolerance for noise compared to the previous 2-dimensional SQKD protocol. Our results highlight that, similar to the fully quantum key distribution protocol, increasing the dimension of the system can increase the noise tolerance in the semi-quantum key distribution, as well.