2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/93094We discuss the robustness of two-way quantum communication protocols against Trojan horse attack and introduce a novel attack, delay-photon Trojan horse attack. Moreover, we present a practical way for two-way quantum communication protocols to prevent the eavesdropper from stealing the information transmitted with Trojan horse attacks. It means that two-way quantum communication protocols is also secure in a practical application.3 pages, no figure. Comments and helps are welcome to fgdeng@bnu.edu.cnQuantum Physicstext