24 research outputs found
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
Generalized DC loop current attack against the KLJN secure key exchange scheme
A new attack against the Kirchhoff Law Johnson Noise (KLJN) secure key
distribution system is studied with unknown parasitic DC voltage sources at
both Alices and Bobs ends. This paper is the generalization of our earlier
investigation with a single end parasitic source. Under the assumption that Eve
does not know the values of the parasitic sources, a new attack, utilizing the
current generated by the parasitic dc voltage sources, is introduced. The
attack is mathematically analyzed and demonstrated by computer simulations.
Simple defense methods against the attack are shown. The earlier defense method
based solely on the comparison of current/voltage data at Alice's and Bob's
terminals is useless here since the wire currents and voltages are equal at
both ends. However, the more expensive version of the earlier defense method,
which is based on in situ system simulation and comparison with measurements,
works efficiently.Comment: 11 pages, 6 Figures, and Journal pape
Analysis of an Attenuator Artifact in an Experimental Attack by Gunn鈥揂llison鈥揂bbott Against the Kirchhoff-Law鈥揓ohnson-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
Cable Capacitance Attack against the KLJN Secure Key Exchange
The security of the Kirchhoff-law-Johnson-(like)-noise (KLJN) key exchange
system is based on the Fluctuation-Dissipation-Theorem of classical statistical
physics. Similarly to quantum key distribution, in practical situations, due to
the non-idealities of the building elements, there is a small information leak,
which can be mitigated by privacy amplification or other techniques so that the
unconditional (information theoretic) security is preserved. In this paper, the
industrial cable and circuit simulator LTSPICE is used to validate the
information leak due to one of the non-idealities in KLJN, the parasitic
(cable) capacitance. Simulation results show that privacy amplification and/or
capacitor killer (capacitance compensation) arrangements can effectively
eliminate the leak.Comment: Accepted for publication in the journal: Informatio