Source noise affects the security of continuous-variable quantum key distribution (CV QKD), and is diffcult to analyze. We propose a model to characterize Gaussian source noise through introducing a neutral party (Fred) who induces the noise with a general unitary transformation. Without knowing Fred's exact state, we derive the security bounds for both reverse and direct reconciliations and show that the bound for reverse reconciliation is tight.
@article{arxiv.1101.0871,
title = {Continuous-variable quantum key distribution with Gaussian source noise},
author = {Yujie Shen and Xiang Peng and Jian Yang and Hong Guo},
journal= {arXiv preprint arXiv:1101.0871},
year = {2011}
}