Experimental study of the Kirchhoff-Law-Johnson-Noise secure key exchange

2014 ◽  
Vol 33 ◽  
pp. 1460365 ◽  
Author(s):  
Robert Mingesz

The Kirchhoff-Law-Johnson-Noise (KLJN) secure key distribution system provides a way of exchanging secure keys by using classical physics (electricity and thermodynamics). Several theoretical studies have addressed the performance and applicability of the communication protocol, and they have indicated that it is protected against all known types of attacks. However, until now, there have been very few real physical implementations and experimental tests of the protocol. With our work, we continue filling this gap. Details of implementing a KLJN based system are presented using a dedicated hardware and an off-the-shelf solution as well. Furthermore, the results of experimental tests and analysis of the performance will be presented.

2016 ◽  
Vol 23 (3) ◽  
pp. 321-331 ◽  
Author(s):  
Laszlo 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.


2014 ◽  
Vol 33 ◽  
pp. 1460368
Author(s):  
Janusz Smulko

The Kirchhoff-Law-Johnson-Noise (KLJN) secure key distribution system provides a way of exchanging information theoretic secure keys by measuring the random voltage and current through the wire connecting two different resistors at Alice's and Bob's ends. Recently new advanced protocols for the KLJN method have been proposed with enhanced performance. In this paper we analyze the KLJN system and compare with “intelligent” KLJN (iKLJN) scheme. This task requires the determination of the applied resistors and the identification of the various superpositions of known and unknown noise components. Some statistical tools to determine how the duration of the bit exchange window (averaging time) influences the performance of secure bit exchange will be explored.


2014 ◽  
Vol 13 (03) ◽  
pp. 1450024 ◽  
Author(s):  
Janusz Smulko

The Kirchhoff-law–Johnson-noise (KLJN) secure key distribution system provides a way of exchanging theoretically secure keys by measuring random voltage and current through the wire connecting two different resistors at Alice's and Bob's ends. Recently new advanced protocols for the KLJN method have been proposed with enhanced performance. In this paper, we analyze the KLJN system and compare with the "intelligent" KLJN (iKLJN) scheme. That task requires determination of the applied resistors and identification of various superpositions of known and unknown noise components. Some statistical tools will be explored to determine how the duration of the bit exchange window (averaging time) influences the performance of the secure bit exchange.


2014 ◽  
Vol 33 ◽  
pp. 1460367 ◽  
Author(s):  
Yessica Saez ◽  
Laszlo B. Kish ◽  
Robert Mingesz ◽  
Zoltan Gingl ◽  
Claes G. Granqvist

We classify and analyze bit errors in the voltage and current measurement modes of the Kirchhoff-law–Johnson-noise (KLJN) secure key distribution system. In both measurement modes, the error probability decays exponentially with increasing duration of the bit sharing period (BSP) at fixed bandwidth. We also present an error mitigation strategy based on the combination of voltage-based and current-based schemes. The combination method has superior fidelity, with drastically reduced error probability compared to the former schemes, and it also shows an exponential dependence on the duration of the BSP.


2013 ◽  
Vol 20 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Robert Mingesz ◽  
Laszlo Bela Kish ◽  
Zoltan Gingl ◽  
Claes-Göran Granqvist ◽  
He Wen ◽  
...  

Abstract There is an ongoing debate about the fundamental security of existing quantum key exchange schemes. This debate indicates not only that there is a problem with security but also that the meanings of perfect, imperfect, conditional and unconditional (information theoretic) security in physically secure key exchange schemes are often misunderstood. It has been shown recently that the use of two pairs of resistors with enhanced Johnsonnoise and a Kirchhoff-loop ‒ i.e., a Kirchhoff-Law-Johnson-Noise (KLJN) protocol ‒ for secure key distribution leads to information theoretic security levels superior to those of today’s quantum key distribution. This issue is becoming particularly timely because of the recent full cracks of practical quantum communicators, as shown in numerous peer-reviewed publications. The KLJN system is briefly surveyed here with discussions about the essential questions such as (i) perfect and imperfect security characteristics of the key distribution, and (ii) how these two types of securities can be unconditional (or information theoretical).


2014 ◽  
Vol 21 (3) ◽  
pp. 389-400 ◽  
Author(s):  
Hsien-Pu Chen ◽  
Laszlo B. Kish ◽  
Claes G. Granqvist ◽  
Claes G. Granqvist

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.


2014 ◽  
Vol 14 (01) ◽  
pp. 1550008 ◽  
Author(s):  
X. Cao ◽  
Y. Saez ◽  
G. Pesti ◽  
L. B. Kish

In a former paper [Fluct. Noise Lett. 13 (2014) 1450020] we introduced a vehicular communication system with unconditionally secure key exchange based on the Kirchhoff-Law–Johnson-Noise (KLJN) key distribution scheme. In this paper, we address the secure KLJN key donation to vehicles. This KLJN key donation solution is performed lane-by-lane by using roadside key provider equipment embedded in the pavement. A method to compute the lifetime of the KLJN key is also given. This key lifetime depends on the car density and gives an upper limit of the lifetime of the KLJN key for vehicular communication networks.


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