Practical Quantum Digital Signature

TL;DR

This paper introduces a practical quantum digital signature protocol that removes the need for authenticated quantum channels and remains secure over long distances, advancing secure quantum communication.

Contribution

It presents the first QDS protocol that is both practical and secure without authenticated channels, suitable for real-world implementation over 100 km.

Findings

Removes the requirement of authenticated quantum channels.

Secure against collective attacks.

Feasible over 100 km with current technology.

Abstract

Guaranteeing nonrepudiation, unforgeability as well as transferability of a signature is one of the most vital safeguards in today's e-commerce era. Based on fundamental laws of quantum physics, quantum digital signature (QDS) aims to provide information-theoretic security for this cryptographic task. However, up to date, the previously proposed QDS protocols are impractical due to various challenging problems and most importantly, the requirement of authenticated (secure) quantum channels between participants. Here, we present the first quantum digital signature protocol that removes the assumption of authenticated quantum channels while remaining secure against the collective attacks. Besides, our QDS protocol can be practically implemented over more than 100 km under current mature technology as used in quantum key distribution.