Efficient Quantum Digital Signatures without Symmetrization Step

TL;DR

This paper introduces an efficient quantum digital signature protocol that eliminates the need for symmetrization and achieves a linear signature rate scaling, significantly improving performance over previous methods.

Contribution

The authors develop a quantum digital signature protocol using post-matching that removes the symmetrization step and enhances signature rate scalability.

Findings

Signature rate is three orders of magnitude higher in simulations.

Protocol is compatible with existing quantum communication infrastructure.

Achieves unconditional security without symmetrization step.

Abstract

Quantum digital signatures (QDS) exploit quantum laws to guarantee non-repudiation, unforgeability and transferability of messages with information-theoretic security. Current QDS protocols face two major restrictions, including the requirement of the symmetrization step with additional secure classical channels and quadratic scaling of the signature rate with the probability of detection events. Here, we present an efficient QDS protocol to overcome these issues by utilizing the classical post-processing operation called post-matching method. Our protocol does not need the symmetrization step, and the signature rate scales linearly with the probability of detection events. Simulation results show that the signature rate is three orders of magnitude higher than the original protocol in a 100-km-long fiber. This protocol is compatible with existing quantum communication infrastructure, therefore we anticipate that it will play a significant role in providing digital signatures with unconditional security.