General Trojan horse attacks on quantum key distribution systems are analyzed. We illustrate the power of such attacks with today's technology and conclude that all system must implement active counter-measures. In particular all systems must include an auxiliary detector that monitors any incoming light. We show that such counter-measures can be efficient, provided enough additional privacy amplification is applied to the data. We present a practical way to reduce the maximal information gain that an adversary can gain using Trojan horse attacks. This does reduce the security analysis of the 2-way {\it Plug-&-Play} system to those of the standard 1-way systems.
Cite
@article{arxiv.quant-ph/0507063,
title = {Trojan Horse attacks on Quantum Key Distribution systems},
author = {N. Gisin and S. Fasel and B. Kraus and H. Zbinden and G. Ribordy},
journal= {arXiv preprint arXiv:quant-ph/0507063},
year = {2013}
}
Comments
7 pages; refs added and a new paragraph on the reduction of the security analysis of 2-way quantum cryptography systems to the security of 1-way systems