Quantum Key Distribution with Imperfections: Recent Advances in Security Proofs

TL;DR

This paper reviews recent advances in security proofs for Quantum Key Distribution (QKD) that incorporate practical imperfections, bridging the gap between theoretical guarantees and real-world implementations.

Contribution

It provides an overview of analytical and numerical methods to include imperfections in QKD security proofs, enhancing their practical relevance.

Findings

Security proofs now account for physical system imperfections.

Recent methods improve the robustness of QKD against real-world attacks.

The overview highlights versatile approaches for realistic security analysis.

Abstract

In contrast to classical cryptography, where the security of encoded messages typically relies on the inability of standard algorithms to overcome computational complexity assumptions, Quantum Key Distribution (QKD) can enable two spatially separated parties to establish an information-theoretically secure encryption, provided that the QKD protocol is underpinned by a security proof. In the last decades, security proofs robust against a wide range of eavesdropping strategies have established the theoretical soundness of several QKD protocols. However, most proofs are based on idealized models of the physical systems involved in such protocols and often include assumptions that are not satisfied in practical implementations. This mismatch creates a gap between theoretical security guarantees and actual experimental realizations, making QKD protocols vulnerable to attacks. To ensure the security of real-world QKD systems, it is therefore essential to account for imperfections in security analyses. In this article, we present an overview of recent analytical and numerical developments in QKD security proofs, which provide a versatile approach for incorporating imperfections and re-establishing the security of quantum communication protocols under realistic conditions.