Secure quantum key distribution with realistic devices

TLDR

Quantum key distribution offers information‑theoretic security, but realistic device imperfections can cause deviations from idealized security models. The article investigates whether quantum code‑breakers can exploit side channels in real systems and whether quantum code‑makers can develop counter‑measures. It reviews theoretical and experimental progress in the practical security of quantum code‑making and code‑breaking. Researchers now fully understand and manage practical imperfections, and recent advances such as the measurement‑device‑independent protocol have closed critical side channels, enabling secure QKD with realistic devices.

Abstract

In principle, quantum key distribution (QKD) offers information-theoretic security based on the laws of physics. In practice, however, the imperfections of realistic devices might introduce deviations from the idealized models used in security analyses. Can quantum code-breakers successfully hack real systems by exploiting the side channels? Can quantum code-makers design innovative counter-measures to foil quantum code-breakers? This article reviews theoretical and experimental progress in the practical security aspects of quantum code-making and quantum code-breaking. After numerous attempts, researchers now thoroughly understand and are able to manage the practical imperfections. Recent advances, such as the measurement-device-independent protocol, have closed the critical side channels in the physical implementations, paving the way for secure QKD with realistic devices.