Signing Information in the Quantum Era

TL;DR

This paper reviews the evolution of digital signatures, discusses the threats posed by quantum computing, and explores post-quantum and quantum channel signing schemes for future secure communication.

Contribution

It provides a comprehensive overview of current signature schemes, analyzes their vulnerabilities to quantum attacks, and introduces emerging post-quantum and quantum channel signing methods.

Findings

Current digital signatures are vulnerable to quantum algorithms.

Post-quantum schemes aim to resist quantum attacks while maintaining practicality.

Quantum channel signatures offer provable security based on quantum mechanics.

Abstract

Signatures are primarily used as a mark of authenticity, to demonstrate that the sender of a message is who they claim to be. In the current digital age, signatures underpin trust in the vast majority of information that we exchange, particularly on public networks such as the internet. However, schemes for signing digital information which are based on assumptions of computational complexity are facing challenges from advances in mathematics, the capability of computers, and the advent of the quantum era. Here we present a review of digital signature schemes, looking at their origins and where they are under threat. Next, we introduce post-quantum digital schemes, which are being developed with the specific intent of mitigating against threats from quantum algorithms whilst still relying on digital processes and infrastructure. Finally, we review schemes for signing information carried on quantum channels, which promise provable security metrics. Signatures were invented as a practical means of authenticating communications and it is important that the practicality of novel signature schemes is considered carefully, which is kept as a common theme of interest throughout this review.