Stuttgart 2012 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 54: Poster 3
Q 54.8: Poster
Thursday, March 15, 2012, 16:30–19:00, Poster.I+II
Investigating the feasibility of a practical Trojan-horse attack on a commercial quantum cryptosystem — •Nitin Jain1,2, Elena Anisimova3, Christoffer Wittmann1,2, Christoph Marquardt1,2, Vadim Makarov3, and Gerd Leuchs1,2 — 1Max Planck Institute for the Science of Light, Erlangen, Germany — 2Institut fuer Optik, Information und Photonik, University of Erlangen-Nuremberg, Germany — 3Department of Electronics and Telecommunications, Norwegian University of Science and Technology, Trondheim, Norway
An optical component inside a quantum key distribution (QKD) system may be probed via the quantum channel by sending in sufficiently intense light and analyzing the back-reflected light. This forms the basis of a Trojan-horse attack. We experimentally review the feasibility of such an attack on a commercially available QKD system from ID Quantique. The objective is to read Bob's phase modulator (to acquire knowledge of his basis choice) without alerting him; this breaches the Scarani-Acin-Ribordy-Gisin protocol. Using optical time domain reflectometry, we prepared optical maps of Bob's module at three different wavelengths: 806, 1310 and 1550 nm. With the intensity of Eve's input light chosen so as to obtain a requisite back-reflection level (5-10 photons per pulse), we find a strong afterpulsing ensues in Bob's detectors. This would cause a high QBER that would stop the QKD exchange, so we are now exploring the longer wavelength (1630-2000 nm) regime, where we conjecture a weaker afterpulsing would allow us to craft and execute a successful attack.