Comment on "An arbitrated quantum signature scheme with fast signing and verifying"

TL;DR

This paper critically analyzes a recent arbitrated quantum signature scheme, revealing that a malicious verifier can forge signatures under certain attacks, thus exposing security vulnerabilities in the proposed protocol.

Contribution

It identifies and demonstrates a security flaw in Liu et al.'s quantum signature scheme, specifically showing how a malicious verifier can forge signatures without detection.

Findings

Malicious Bob can perform existential forgery of signatures

The scheme is vulnerable under chosen message attacks

Security flaws compromise the scheme's reliability

Abstract

Recently, Liu et al. (Quantum Inf Process (2014) 13:491-502) proposed an arbitrated quantum signature (AQS) scheme, where a signature receiver (Bob) can verify the signer's signature through the help of a trusted arbitrator. However, this paper shows that a malicious Bob can perform the existential forgery of the signature under the chosen message attack without being detected.