Cryptanalysis of quantum secure direct communication protocol with mutual authentication based on single photons and Bell states

Recently, Yan et al. proposed a quantum secure direct communication (QSDC) protocol with authentication using single photons and Einstein-Podolsky-Rosen (EPR) pairs (Yan al., CMC-Computers, Materials \& Continua, 63(3), 2020). In this work, we show that the QSDC is not against intercept-and-resend attack impersonation attack. An eavesdropper can get full secret message by applying these attacks. We propose modification of protocol, which defeats above attacks along all familiar