Device calibration impacts security of quantum key distribution

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 demons...

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Published inPhysical review letters Vol. 107; no. 11; p. 110501
Main Authors Jain, Nitin, Wittmann, Christoffer, Lydersen, Lars, Wiechers, Carlos, Elser, Dominique, Marquardt, Christoph, Makarov, Vadim, Leuchs, Gerd
Format Journal Article
LanguageEnglish
Published United States 09.09.2011
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Summary: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.
ISSN:1079-7114
DOI:10.1103/physrevlett.107.110501