Characterizing the physical channel and calibrating the cryptosystem hardware are prerequisites for establishing a quantum channel for quantum key distribution (QKD). Moreover, an inappropriately implemented calibration routine can open a fatal security loophole. We propose and experimentally demonstrate a method to induce a large temporal detector efficiency mismatch in a commercial QKD system by deceiving a channel length calibration routine. We then devise an optimal and realistic strategy using faked states to break the security of the cryptosystem. A fix for this loophole is also suggested.
@article{arxiv.1103.2327,
title = {Device calibration impacts security of quantum key distribution},
author = {Nitin Jain and Christoffer Wittmann and Lars Lydersen and Carlos Wiechers and Dominique Elser and Christoph Marquardt and Vadim Makarov and Gerd Leuchs},
journal= {arXiv preprint arXiv:1103.2327},
year = {2011}
}
Comments
4 pages + 1 page of supplementary information. Considerable modification of Eve's attack strategy and QBER minimization technique. All figures have also been improved