Continuous-variable measurement-device-independent quantum key distribution using squeezed states

TL;DR

This paper introduces a CV-MDI QKD protocol using squeezed states that enhances security against detector side channels and achieves higher key rates, with an optimized noise addition method for improved long-distance secure communication.

Contribution

The paper proposes a novel CV-MDI QKD protocol with squeezed states and introduces an optimal noise addition technique to enhance performance and security.

Findings

Protocol defends against detector side channels

Achieves higher secret key rates than coherent-state protocols

Optimal added noise improves transmission distance

Abstract

A continuous-variable measurement-device-independent quantum key distribution (CV-MDI QKD) protocol using squeezed states is proposed where the two legitimate partners send Gaussian-modulated squeezed states to an untrusted third party to realize the measurement. Security analysis shows that the protocol can not only defend all detector side channels, but also attain higher secret key rates than the coherent-state-based protocol. We also present a method to improve the squeezed-state CV-MDI QKD protocol by adding proper Gaussian noise to the reconciliation side. It is found that there is an optimal added noise to optimize the performance of the protocol in terms of both key rates and maximal transmission distances. The resulting protocol shows the potential of long-distance secure communication using the CV-MDI QKD protocol.