Lightweight authenticated semi-quantum key distribution protocol without trojan horse attack

A lightweight authenticated semi-quantum key distribution (LASQKD) protocol is proposed for secure communication. By pre-sharing a master key and adopting a one-way communication strategy, the proposed protocol allows a quantum user and a classical user to share secret keys without using an authenticated classical channel and any Trojan horse detection device. Security analyses show that the proposed LASQKD protocol is free from well-known attacks, and a simulation implementation proves the feasibility of the proposed protocol. Compared to existing authenticated semi-quantum key distribution protocols, the protocol proposed herein provides improved practicality, indicating its potential for use in modern quantum systems.