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ANALYSIS OF THE ATTENUATOR-ARTIFACT IN THE EXPERIMENTAL ATTACK OF GUNN-ALLISON-ABBOTT AGAINST THE KLJN SYSTEM

László B. Kish, Zoltán Gingl, Róbert Mingesz, Gergely Vadai, Janusz Smulko, Claes‐Göran Granqvist

Published Jan 1, 2014• 0 citations
OpenAlex

Abstract

After briefly summarizing our general theoretical arguments, we show that, the experienced strong information leak at the Gunn-Allison-Abbott attack [Scientific Reports 4 (2014) 6461] against the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange scheme, resulted from a serious design flaw of the system. The attenuator broke the single Kirchhoff-loop into two coupled loops. This is an illegal operation because the single loop is essential for the security, thus the observed leak is obvious. We demonstrate this by cracking the system with an elementary current comparison attack yielding close to 1 success probability for Eve even without averaging within a sub-correlation-time measurement window. A fully defended KLJN system would not be able to function, at all, due to its built-in current-comparison defense against active (invasive) attacks.

Related papers

Analysis of an Attenuator Artifact in an Experimental Attack by Gunn–Allison–Abbott Against the Kirchhoff-Law–Johnson-Noise (KLJN) Secure Key Exchange System

Laszlo B. Kish, Zoltán Gingl, Robert Mingesz +3 more

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.

arXiv:1411.0818•Fluctuation and Noise Letters•Dec 25, 2014•38 citations

ON THE "CRACKING" EXPERIMENTS IN GUNN, ALLISON, ABBOTT, "A DIRECTIONAL COUPLER ATTACK AGAINST THE KISH KEY DISTRIBUTION SYSTEM"

Hsien-Pu Chen, László B. Kish, Claes‐Göran Granqvist +1 more

Recently Gunn, Allison and Abbott (GAA) [http://arxiv.org/pdf/1402.2709v2.pdf] proposed a new scheme to utilize electromagnetic waves for eavesdropping on the Kirchhoff-law‐Johnson-noise (KLJN) secure key distribution. In a former paper [http://vixra.org/pdf/1403.0964v4.pdf], we proved that CAA's wave-based attack is unphysical. Here we address their experimental results regarding this attack. Our analysis shows that GAA virtually claim that they can identify, in a few correlation times that, from two Gaussian distributions with zero mean, which one is wider when their relative width difference is <10 -4 . Normally, such decision would need millions of correlations times to observe. We identify the experimental artifact causing this situation: existing DC current and/or ground loop (yielding slow deterministic currents) in the system. It is important to note that, while the GAA's cracking scheme, the experiments and the analysis are invalid, there is an important benefit of their attempt: our analysis implies that, in practical KLJN systems, DC currents ground loops or any other mechanisms carrying a deterministic current/voltage component must be taken care of to avoid information leak about the key.

•Jan 1, 2014•0 citations

Comments on “A New Transient Attack on the Kish Key Distribution System”

László B. Kish, Claes G. Granqvist

Abstract A recent IEEE Access Paper by Gunn, Allison and Abbott (GAA) proposed a new transient attack against the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange system. The attack is valid, but it is easy to build a defense for the KLJN system. Here we note that GAA’s paper contains several invalid statements regarding security measures and the continuity of functions in classical physics. These deficiencies are clarified in our present paper, wherein we also emphasize that a new version of the KLJN system is immune against all existing attacks, including the one by GAA.

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On the “Cracking” Scheme in the Paper “A Directional Coupler Attack Against the Kish Key Distribution System” by Gunn, Allison and Abbott

Hsien-Pu Chen, László B. Kish, Claes G. Granqvist +1 more

Abstract Recently, Gunn, Allison and Abbott (GAA) [http://arxiv.org/pdf/1402.2709v2.pdf] proposed a new scheme to utilize electromagnetic waves for eavesdropping on the Kirchhoff-law-Johnson-noise (KLJN) secure key distribution. We proved in a former paper [Fluct. Noise Lett. 13 (2014) 1450016] that GAA’s mathematical model is unphysical. Here we analyze GAA’s cracking scheme and show that, in the case of a loss-free cable, it provides less eavesdropping information than in the earlier (Bergou)-Scheuer-Yariv mean-square-based attack [Kish LB, Scheuer J, Phys. Lett. A 374:2140-2142 (2010)], while it offers no information in the case of a lossy cable. We also investigate GAA’s claim to be experimentally capable of distinguishing—using statistics over a few correlation times only—the distributions of two Gaussian noises with a relative variance difference of less than 10-8. Normally such distinctions would require hundreds of millions of correlations times to be observable. We identify several potential experimental artifacts as results of poor KLJN design, which can lead to GAA’s assertions: deterministic currents due to spurious harmonic components caused by ground loops, DC offset, aliasing, non-Gaussian features including non-linearities and other non-idealities in generators, and the timederivative nature of GAA’s scheme which tends to enhance all of these artifacts.

arXiv:1405.2034•Metrology and Measurement Systems•Aug 20, 2014•39 citations

Random Number Generator Attack against the Kirchhoff-Law-Johnson-Noise Secure Key Exchange Protocol

Christiana Chamon, Shahriar Faysal Ferdous, László B. Kish

This paper introduces and demonstrates two new attacks against the Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange scheme. The attacks are based on random number generators with compromised security. First we explore the situation in which Eve knows the seed of both Alice's and Bob's random number generators. We show that in this situation Eve can crack the secure key bit within a fraction of the bit exchange period even if her current and voltage measurements have only a single bit of resolution. In the second attack, we explore the situation in which Eve knows the seed of only Alice's random number generator. We show that in this situation Eve can still crack the secure key bit but she needs to use the whole bit exchange period for the attack. The security of the KLJN key exchange scheme, similarly to other protocols, necessitates that the random number generator outputs are truly random for Eve.

arXiv:2005.10429•May 21, 2020•2 citations

The problem of information leak due to parasitic loop currents and voltages in the KLJN secure key exchange scheme

Mutaz Y. Melhem, László B. Kish

The Kirchhoff-law-Johnson-noise (KLJN) secure key exchange scheme offers unconditional security, however it can approach the perfect security limit only in the case when the practical system's parameters approach the ideal behavior of its core circuitry.In the case of non-ideal features, non-zero information leak is present.The study of such leaks is important for a proper design of practical KLJN systems and their privacy amplifications in order to eliminate these problems.

Metrology and Measurement Systems•Jan 15, 2019•18 citations
After briefly summarizing our general theoretical arguments, we show that, the experienced strong information leak at the Gunn-Allison-Abbott attack [Scientific Reports 4 (2014) 6461] against the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange scheme, resulted from a serious design flaw of the system. The attenuator broke the single Kirchhoff-loop into two coupled loops. This is an illegal operation because the single loop is essential for the security, thus the observed leak is obvious. We demonstrate this by cracking the system with an elementary current comparison attack yielding close to 1 success probability for Eve even without averaging within a sub-correlation-time measurement window. A fully defended KLJN system would not be able to function, at all, due to its built-in current-comparison defense against active (invasive) attacks.
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.
Recently Gunn, Allison and Abbott (GAA) [http://arxiv.org/pdf/1402.2709v2.pdf] proposed a new scheme to utilize electromagnetic waves for eavesdropping on the Kirchhoff-law‐Johnson-noise (KLJN) secure key distribution. In a former paper [http://vixra.org/pdf/1403.0964v4.pdf], we proved that CAA's wave-based attack is unphysical. Here we address their experimental results regarding this attack. Our analysis shows that GAA virtually claim that they can identify, in a few correlation times that, from two Gaussian distributions with zero mean, which one is wider when their relative width difference is <10 -4 . Normally, such decision would need millions of correlations times to observe. We identify the experimental artifact causing this situation: existing DC current and/or ground loop (yielding slow deterministic currents) in the system. It is important to note that, while the GAA's cracking scheme, the experiments and the analysis are invalid, there is an important benefit of their attempt: our analysis implies that, in practical KLJN systems, DC currents ground loops or any other mechanisms carrying a deterministic current/voltage component must be taken care of to avoid information leak about the key.
Abstract A recent IEEE Access Paper by Gunn, Allison and Abbott (GAA) proposed a new transient attack against the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange system. The attack is valid, but it is easy to build a defense for the KLJN system. Here we note that GAA’s paper contains several invalid statements regarding security measures and the continuity of functions in classical physics. These deficiencies are clarified in our present paper, wherein we also emphasize that a new version of the KLJN system is immune against all existing attacks, including the one by GAA.
Abstract Recently, Gunn, Allison and Abbott (GAA) [http://arxiv.org/pdf/1402.2709v2.pdf] proposed a new scheme to utilize electromagnetic waves for eavesdropping on the Kirchhoff-law-Johnson-noise (KLJN) secure key distribution. We proved in a former paper [Fluct. Noise Lett. 13 (2014) 1450016] that GAA’s mathematical model is unphysical. Here we analyze GAA’s cracking scheme and show that, in the case of a loss-free cable, it provides less eavesdropping information than in the earlier (Bergou)-Scheuer-Yariv mean-square-based attack [Kish LB, Scheuer J, Phys. Lett. A 374:2140-2142 (2010)], while it offers no information in the case of a lossy cable. We also investigate GAA’s claim to be experimentally capable of distinguishing—using statistics over a few correlation times only—the distributions of two Gaussian noises with a relative variance difference of less than 10-8. Normally such distinctions would require hundreds of millions of correlations times to be observable. We identify several potential experimental artifacts as results of poor KLJN design, which can lead to GAA’s assertions: deterministic currents due to spurious harmonic components caused by ground loops, DC offset, aliasing, non-Gaussian features including non-linearities and other non-idealities in generators, and the timederivative nature of GAA’s scheme which tends to enhance all of these artifacts.
This paper introduces and demonstrates two new attacks against the Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange scheme. The attacks are based on random number generators with compromised security. First we explore the situation in which Eve knows the seed of both Alice's and Bob's random number generators. We show that in this situation Eve can crack the secure key bit within a fraction of the bit exchange period even if her current and voltage measurements have only a single bit of resolution. In the second attack, we explore the situation in which Eve knows the seed of only Alice's random number generator. We show that in this situation Eve can still crack the secure key bit but she needs to use the whole bit exchange period for the attack. The security of the KLJN key exchange scheme, similarly to other protocols, necessitates that the random number generator outputs are truly random for Eve.