22 research outputs found
Noise properties in the ideal Kirchhoff-Law-Johnson-Noise secure communication system
In this paper we determine the noise properties needed for unconditional
security for the ideal Kirchhoff-Law-Johnson-Noise (KLJN) secure key
distribution system using simple statistical analysis. It has already been
shown using physical laws that resistors and Johnson-like noise sources provide
unconditional security. However real implementations use artificial noise
generators, therefore it is a question if other kind of noise sources and
resistor values could be used as well. We answer this question and in the same
time we provide a theoretical basis to analyze real systems as well
What kind of noise guarantees security for the Kirchhoff-Loop-Johnson-Noise key exchange?
This article is a supplement to our recent one about the analysis of the
noise properties in the Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange
system [Gingl and Mingesz, PLOS ONE 9 (2014) e96109,
doi:10.1371/journal.pone.0096109]. Here we use purely mathematical statistical
derivations to prove that only normal distribution with special scaling can
guarantee security. Our results are in agreement with earlier physical
assumptions [Kish, Phys. Lett. A 352 (2006) 178-182, doi:
10.1016/j.physleta.2005.11.062]. Furthermore, we have carried out numerical
simulations to show that the communication is clearly unsecure for improper
selection of the noise properties. Protection against attacks using time and
correlation analysis is not considered in this paper
Analysis of an attenuator artifact in an experimental attack by Gunn-Allison-Abbott against the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange system
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.Comment: Accepted for publication in Fluctuation and Noise Letters, on
November 3, 201
Current Injection Attack against the KLJN Secure Key Exchange
The Kirchhoff-law-Johnson-noise (KLJN) scheme is a statistical/physical
secure key exchange system based on the laws of classical statistical physics
to provide unconditional security. We used the LTSPICE industrial cable and
circuit simulator to emulate one of the major active (invasive) attacks, the
current injection attack, against the ideal and a practical KLJN system,
respectively. We show that two security enhancement techniques, namely, the
instantaneous voltage/current comparison method, and a simple privacy
amplification scheme, independently and effectively eliminate the information
leak and successfully preserve the system's unconditional security