Comment on "Controlled mutual quantum entity authentication using entanglement swapping"

TL;DR

This paper critically analyzes a quantum authentication protocol and reveals a security flaw that allows an eavesdropper to secretly access shared keys without detection.

Contribution

It identifies a security vulnerability in Kang et al.'s protocol, demonstrating that it is not secure against eavesdropping by the controller.

Findings

Charlie can eavesdrop without detection

The protocol is insecure against internal attacks

Security flaws compromise the protocol's reliability

Abstract

Kang et al. [Chin. Phys. B 24 (2015) 090306] proposed a controlled mutual quantum entity authentication protocol. We find that the proposed protocol is not secure, that is, Charlie can eavesdrop the shared keys between Alice and Bob without being detected.