On the security of arbitrated quantum signature schemes

TL;DR

This paper critically examines arbitrated quantum signature schemes, revealing that all existing schemes are vulnerable to message exchange and denial attacks, and discusses potential improvements for enhanced security.

Contribution

It demonstrates the insecurity of all previous AQS schemes and explores methods for their further improvement.

Findings

All previous AQS schemes are insecure against message exchange attacks.

Receivers can deny accepting signatures of specific messages.

Proposes potential methods for improving AQS scheme security.

Abstract

Due to potential capability of providing unconditional security, arbitrated quantum signature (AQS) schemes, whose implementation depends on the participation of a trusted third party, received intense attention in the past decade. Recently, some typical AQS schemes were cryptanalyzed and improved. In this paper, we analyze security property of some AQS schemes and show that all the previous AQS schemes, no matter original or improved, are still insecure in the sense that the messages and the corresponding signatures can be exchanged among different receivers, allowing the receivers to deny accepting the signature of an appointed message. Some further improvement methods on the AQS schemes are also discussed.