Unidimensional continuous-variable quantum key distribution

TL;DR

This paper introduces a simplified unidimensional continuous-variable quantum key distribution protocol that uses Gaussian modulation of a single quadrature, reducing implementation complexity while maintaining security under certain conditions.

Contribution

It proposes a new unidimensional CV-QKD protocol that simplifies implementation by eliminating phase quadrature modulation and channel transmittance estimation, with security analysis against collective attacks.

Findings

Protocol is secure under specific conditions in phase-sensitive Gaussian channels.

Robustness to channel imperfections is comparable to symmetrical protocols.

Achieves reasonable key rates with tolerable channel noise.

Abstract

We propose the continuous-variable quantum key distribution protocol based on the Gaussian modulation of a single quadrature of the coherent states of light, which is aimed to provide simplified implementation compared to the symmetrically modulated Gaussian coherent-state protocols. The protocol waives the necessity in phase quadrature modulation and the corresponding channel transmittance estimation. The security of the protocol against collective attacks in a generally phase-sensitive Gaussian channels is analyzed and is shown achievable upon certain conditions. Robustness of the protocol to channel imperfections is compared to that of the symmetrical coherent-state protocol. The simplified unidimensional protocol is shown possible at a reasonable quantitative cost in terms of key rate and of tolerable channel excess noise.