2014/11/04 by Laszlo B. Kish, Zoltan Gingl, Robert Mingesz +3 · 2 citations
Computer Science · #cs.CR
paper · pdf · doi:10.1142/s021947751550011x
published as Fluct. Noise Lett. 14 (2015) 1550011 · Accepted for publication in Fluctuation and Noise Letters, on November 3, 2014
arxiv created 2014/11/04 · arxiv updated 2015/03/30
A recent paper by Gunn-Allison-Abbott (GAA) [L.J. Gunn et al., Scientific Reports 4 (2014) 6461] argued that the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange system could experience a severe information leak. Here we refute their results and demonstrate that GAA's arguments ensue from a serious design flaw in their system. Specifically, an attenuator broke the single Kirchhoff-loop into two coupled loops, which is an incorrect operation since the single loop is essential for the security in the KLJN system, and hence GAA's asserted information leak is trivial. Another consequence is that a fully defended KLJN system would not be able to function due to its built-in current-comparison defense against active (invasive) attacks. In this paper we crack GAA's scheme via an elementary current comparison attack which yields negligible error probability for Eve even without averaging over the correlation time of the noise.