Secure Quantum Signatures Using Insecure Quantum Channels

TL;DR

This paper introduces a quantum signature scheme that is unconditionally secure without trusted quantum channels, requiring fewer quantum states and tolerating higher noise levels than previous methods, making it potentially more practical.

Contribution

It presents a novel quantum signature scheme that does not depend on trusted channels and demonstrates advantages over prior schemes in security and efficiency.

Findings

Unconditionally secure against coherent attacks

Requires fewer quantum states than previous schemes

Has a higher noise threshold for quantum channels

Abstract

Digital signatures are widely used in modern communication to guarantee authenticity and transferability of messages, The security of currently used classical schemes relies on computational assumptions. We present a quantum signature scheme that does not require trusted quantum channels. We prove that it is unconditionally secure against the most general coherent attacks, and show that it requires the transmission of significantly fewer quantum states than previous schemes. We also show that the quantum channel noise threshold for our scheme is less strict than for distilling a secure key using quantum key distribution. This shows that direct quantum signature schemes can be preferable to signature schemes relying on secret shared keys generated using quantum key distribution.