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

¹ Applied Statistics Unit, Indian Statistical Institute - Kolkata 700108, India
² Cryptology and Security Research Unit, R. C. Bose Centre for Cryptology and Security, Indian Statistical Institute Kolkata 700108, India

^(a) dasnayana92@gmail.com
^(b) goutam.paul@isical.ac.in (corresponding author)

Received: 8 April 2021
Accepted: 30 August 2021

Abstract

Recently, Yan et al. proposed a quantum secure direct communication (QSDC) protocol with authentication using single photons and Einstein-Podolsky-Rosen (EPR) pairs (Yan L. et al., Comput. Mater. Contin., 63 (2020) 1297). In this work, we show that the above QSDC protocol is secure neither against intercept-and-resend attack, nor against impersonation attack. With any of these two types of attacks, an eavesdropper can recover the full secret message. We also propose a suitable modification of this protocol, which not only defeats the above attacks, but also resists all other common attacks. Thus, our modified protocol provides an improvement over the existing one in terms of security.