Towards Global Quantum Key Distribution

TL;DR

This paper reviews the progress and challenges in developing a global quantum key distribution network, emphasizing protocols, devices, and future research directions to overcome practical and performance limitations.

Contribution

It provides a comprehensive overview of current QKD implementations, discusses challenges, and highlights innovations like satellite-based QKD and new protocols for global deployment.

Findings

Advances in satellite-based QKD enable long-distance secure communication.

Development of new protocols addresses practical security and performance issues.

Future research directions are identified to realize a worldwide QKD network.

Abstract

Quantum Key Distribution (QKD) supports the negotiation and sharing of private keys with unconditional security between authorized parties. Over the years, theoretical advances and experimental demonstrations have successfully transitioned QKD from laboratory research to commercial applications. As QKD expands its reach globally, it encounters challenges such as performance limitations, cost, and practical security concerns. Nonetheless, innovations in satellite-based QKD and the development of new protocols are paving the way towards a worldwide network. In this review, we provide an overview of QKD implementations, with a focus on protocols, devices, and quantum channels. We discuss the challenges of practical QKD and explore long-haul QKD. Additionally, we highlight the future research directions that are expected to significantly advance the realization of a global QKD network.