Security of quantum key distribution with source and detector imperfections through phase-error estimation

TL;DR

This paper develops a unified security proof for quantum key distribution that accounts for both source and detector imperfections, bridging the gap between theory and real-world applications.

Contribution

It combines existing techniques to address both imperfections simultaneously, advancing practical security in QKD systems.

Findings

Unified security proof for BB84 protocols with imperfections

Enhanced robustness of QKD against device flaws

Progress towards real-world secure quantum communication

Abstract

Quantum key distribution (QKD) promises information-theoretic security based on quantum mechanics, but practical implementations face security vulnerabilities due to device imperfections. Recent advances have separately addressed source and detector imperfections in phase-error-estimation based security proof frameworks, but this is not enough to protect real-world QKD systems suffering from both types of imperfections simultaneously. In this work, we show that existing techniques for BB84-type protocols can be combined to construct a unified security proof that simultaneously accounts for both source and detector imperfections. Our approach thus represents a significant step towards closing the gap between theoretical security proofs and practical QKD implementations.