We propose a quantum key distribution scheme which closely matches the performance of a perfect single photon source. It nearly attains the physical upper bound in terms of key generation rate and maximally achievable distance. Our scheme relies on a practical setup based on a parametric downconversion source and present-day, non-ideal photon-number detection. Arbitrary experimental imperfections which lead to bit errors are included. We select decoy states by classical post-processing. This allows to improve the effective signal statistics and achievable distance.
@article{arxiv.quant-ph/0609195,
title = {Passive decoy state quantum key distribution: Closing the gap to perfect sources},
author = {Wolfgang Mauerer and Christine Silberhorn},
journal= {arXiv preprint arXiv:quant-ph/0609195},
year = {2007}
}