On the lightweight authenticated semi-quantum key distribution protocol without Trojan horse attack

TL;DR

This paper analyzes a semi-quantum key distribution protocol, identifies security vulnerabilities, and proposes an improved version to prevent undetected modification attacks, enhancing the protocol's robustness.

Contribution

It introduces a modification to the existing lightweight semi-quantum key distribution protocol to prevent undetected modification attacks.

Findings

Original protocol is vulnerable to modification attacks

Proposed improvements effectively prevent undetected attacks

Enhanced protocol maintains lightweight and security features

Abstract

Recently, Tsai et al. (Laser Phys. Lett. 17, 075202, 2020) proposed a lightweight authenticated semi-quantum key distribution protocol for a quantum participant to share a secret key with a classical participant. However, this study points out that an attacker can use a modification attack to make both participants share a wrong key without being detected. To avoid this problem, an improvement is proposed here.