In this paper, we consider continuous-variable quantum key distribution with a discrete modulation, either binary or quaternary. We establish the security of these protocols against the class of collective attacks that induce a linear quantum channel. In particular, all Gaussian attacks are taken into account, as well as linear attacks which add a non-Gaussian noise. We give lower bounds for the secret key rate using extremality properties of Gaussian states.
@article{arxiv.1002.4083,
title = {Continuous-variable Quantum Key Distribution protocols with a discrete modulation},
author = {Anthony Leverrier and Philippe Grangier},
journal= {arXiv preprint arXiv:1002.4083},
year = {2015}
}