Composable security for continuous variable quantum key distribution: Trust levels and practical key rates in wired and wireless networks

TL;DR

This paper develops a comprehensive framework for the security analysis of continuous variable quantum key distribution (CV-QKD) in wired and wireless networks, demonstrating high key rates in short-range optical wireless and microwave applications.

Contribution

It introduces a general framework for the composable finite-size security of CV-QKD considering various trust levels and applies it to both fiber-based and wireless scenarios.

Findings

High key rates achievable in short-range optical wireless (LiFi) networks.

Feasibility of CV-QKD in microwave WiFi for very short-range applications.

Security analysis accommodating different trust assumptions for loss and noise.

Abstract

Continuous variable (CV) quantum key distribution (QKD) provides a powerful setting for secure quantum communications, thanks to the use of room-temperature off-the-shelf optical devices and the potential to reach much higher rates than the standard discrete-variable counterpart. In this work, we provide a general framework for studying the composable finite-size security of CV-QKD with Gaussian-modulated coherent-state protocols under various levels of trust for the loss and noise experienced by the parties. Our study considers both wired (i.e., fiber-based) and wireless (i.e., free-space) quantum communications. In the latter case, we show that high key rates are achievable for short-range optical wireless (LiFi) in secure quantum networks with both fixed and mobile devices. Finally, we extend our investigation to microwave wireless (WiFi) discussing security and feasibility of CV-QKD for very short-range applications.