| 1. |
- Kish, Lazar L, et al.
(author)
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Log-normal distribution of single molecule fluorescence bursts in micro/nano-fluidic channels
- 2011
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 99:14, s. 143121-
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Journal article (peer-reviewed)abstract
- The width and shape of photon burst histograms pose significant limitations to the identification of single molecules in micro/nano-fluidic channels, and the nature of these histograms is not fully understood, To reach a deeper understanding, we performed computer simulations based on a Gaussian beam intensity profile with various fluidic channel diameters and assuming (1) a deterministic (noise-free) case, (2) photon emission/absorption noise, and (3) photon noise with diffusion. Photon noise in narrow channels yields a Gaussian burst distribution while additional strong diffusion produces skewed histograms. We use the fluctuating residence time picture Soderlund et al., Phys. Rev, Lett, 80, 2386 (1998)1 and conclude that the skewness of the photon number distribution is caused by the longitudinal diffusive component of the motion of the molecules as they traverse the laser beam. In the case of strong diffusion in narrow channels, this effect leads to a log-normal distribution. We show that the same effect can transform the separate peaks of the photon burst histograms of multiple molecule mixtures into a single log-normal shape.
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| 2. |
- Kish, Lazar L., et al.
(author)
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Optimum drift velocity for single molecule fluorescence bursts in micro/nano-fluidic channels
- 2012
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 101:4, s. 043120-
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Journal article (peer-reviewed)abstract
- Photonic burst histograms can be used to identify single protein molecules in micro/nano-fluidic channels provided the width of the histogram is narrow. Photonic shot noise and residence time fluctuations, caused by longitudinal diffusion, are the major sources of the histogram width. This paper is a sequel to an earlier one of ours [L. L. Kish et al., Appl. Phys. Lett. 99, 143121 (2011)] and demonstrates that, for a given diffusion coefficient, an increase of the drift velocity enhances the relative shot noise and decreases the relative residence time fluctuations. This leads to an optimum drift velocity that minimizes the histogram width and maximizes the ability to identify single molecules, which is an important result for applications.
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| 3. |
- Chen, Hsien-Pu, et al.
(author)
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Do Electromagnetic Waves Exist in a Short Cable at Low Frequencies? : What Does Physics Say?
- 2014
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In: Fluctuation and Noise Letters. - 0219-4775 .- 1793-6780. ; 13:2, s. 1450016-
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Journal article (peer-reviewed)abstract
- We refute a physical model, recently proposed by Gunn, Allison and Abbott (GAA) [http://arxiv.org/pdf/1402.2709v2.pdf], to utilize electromagnetic waves for eavesdropping on the Kirchhoff-law-Johnson-noise (KLJN) secure key distribution. Their model, and its theoretical underpinnings, is found to be fundamentally flawed because their assumption of electromagnetic waves violates not only the wave equation but also the second law of thermodynamics, the principle of detailed balance, Boltzmann's energy equipartition theorem, and Planck's formula by implying infinitely strong blackbody radiation. We deduce the correct mathematical model of the GAA scheme, which is based on impedances at the quasi-static limit. Mathematical analysis and simulation results confirm our approach and prove that GAA's experimental interpretation is incorrect too.
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| 4. |
- Kish, Laszlo B., et al.
(author)
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Elimination of a Second-Law-Attack, and All Cable-Resistance-Based Attacks, in the Kirchhoff-Law-Johnson-Noise (KLJN) Secure Key Exchange System
- 2014
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In: Entropy. - : MDPI AG. - 1099-4300. ; 16:10, s. 5223-5231
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Journal article (peer-reviewed)abstract
- We introduce the so far most efficient attack against the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange system. This attack utilizes the lack of exact thermal equilibrium in practical applications and is based on cable resistance losses and the fact that the Second Law of Thermodynamics cannot provide full security when such losses are present. The new attack does not challenge the unconditional security of the KLJN scheme, but it puts more stringent demands on the security/privacy enhancing protocol than for any earlier attack. In this paper we present a simple defense protocol to fully eliminate this new attack by increasing the noise-temperature at the side of the smaller resistance value over the noise-temperature at the side with the greater resistance. It is shown that this simple protocol totally removes Eve's information not only for the new attack but also for the old Bergou-Scheuer-Yariv attack. The presently most efficient attacks against the KLJN scheme are thereby completely nullified.
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| 5. |
- Kish, Laszlo B., et al.
(author)
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Enhanced Usage of Keys Obtained by Physical, Unconditionally Secure Distributions
- 2015
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In: Fluctuation and Noise Letters. - 0219-4775 .- 1793-6780. ; 14:2, s. 1-3
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Journal article (peer-reviewed)abstract
- Unconditionally secure physical key distribution schemes are very slow, and it is practically impossible to use a one-time-pad based cipher to guarantee unconditional security for the encryption of data because using the key bits more than once gives out statistical information, for example via the known-plain-text-attack or by utilizing known components of the protocol and language statistics. Here, we outline a protocol that reduces this speed problem and allows almost-one-time-pad based communication with an unconditionally secure physical key of finite length. The physical, unconditionally secure key is not used for data encryption but is employed in order to generate and share a new software-based key without any known-plain-text component. The software-only-based key distribution is then changed from computationally secure to unconditionally secure, because the communicated key-exchange data (algorithm parameters, one-way functions of random numbers, etc.) are encrypted in an unconditionally secure way with a one-time-pad. For practical applications, this combined physical/software key distribution based communication looks favorable compared to the software-only and physical-only key distribution based communication whenever the speed of the physical key distribution is much lower than that of the software-based key distribution. A mathematical security proof of this new scheme remains an open problem.
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| 6. |
- Kish, Laszlo B., et al.
(author)
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On the security of the Kirchhoff-law-Johnson-noise (KLJN) communicator
- 2014
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In: Quantum Information Processing. - : Springer Science and Business Media LLC. - 1570-0755 .- 1573-1332. ; 13:10, s. 2213-2219
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Journal article (peer-reviewed)abstract
- A simple and general proof is given for the information theoretic (unconditional) security of the Kirchhoff-law-Johnson-noise key exchange system under practical conditions. The unconditional security for ideal circumstances, which is based on the second law of thermodynamics, is found to prevail even under slightly non-ideal conditions. This security level is guaranteed by the continuity of functions describing classical physical linear, as well as stable non-linear, systems. Even without privacy amplification, Eve's probability for successful bit guessing is found to converge toward 0.5-i.e., the perfect security level-when ideal conditions are approached.
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| 7. |
- Kish, Laszlo B., et al.
(author)
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Unconditionally Secure Credit/Debit Card Chip Scheme and Physical Unclonable Function
- 2017
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In: Fluctuation and Noise Letters. - : WORLD SCIENTIFIC PUBL CO PTE LTD. - 0219-4775 .- 1793-6780. ; 16:1
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Journal article (peer-reviewed)abstract
- The statistical-physics-based Kirchhoff-law-Johnson-noise (KLJN) key exchange offers a new and simple unclonable system for credit/ debit card chip authentication and payment. The key exchange, the authentication and the communication are unconditionally secure so that neither mathematics-nor statistics-based attacks are able to crack the scheme. The ohmic connection and the short wiring lengths between the chips in the card and the terminal constitute an ideal setting for the KLJN protocol, and even its simplest versions offer unprecedented security and privacy for credit/debit card chips and applications of physical unclonable functions (PUFs).
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| 8. |
- Kish, Laszlo B., et al.
(author)
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Zero-point term and quantum effects in the Johnson noise of resistors : a critical appraisal
- 2016
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In: Journal of Statistical Mechanics. - : IOP Publishing. - 1742-5468.
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Journal article (peer-reviewed)abstract
- There is a longstanding debate about the zero-point term in the Johnson noise voltage of a resistor. This term originates from a quantum-theoretical treatment of the fluctuation-dissipation theorem (FDT). Is the zero-point term really there, or is it only an experimental artifact, due to the uncertainty principle, for phase-sensitive amplifiers? Could it be removed by renormalization of theories? We discuss some historical measurement schemes that do not lead to the effect predicted by the FDT, and we analyse new features that emerge when the consequences of the zero-point term are measured via the mean energy and force in a capacitor shunting the resistor. If these measurements verify the existence of a zero-point term in the noise, then two types of perpetual motion machines can be constructed. Further investigation with the same approach shows that, in the quantum limit, the Johnson-Nyquist formula is also invalid under general conditions even though it is valid for a resistor-antenna system. Therefore we conclude that in a satisfactory quantum theory of the Johnson noise, the FDT must, as a minimum, include also the measurement system used to evaluate the observed quantities. Issues concerning the zero-point term may also have implications for phenomena in advanced nanotechnology.
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| 9. |
- Chen, Hsien-Pu, et al.
(author)
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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
- 2014
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In: METROLOGY AND MEASUREMENT SYSTEMS. - : Polish Academy of Sciences Chancellery. - 0860-8229 .- 2300-1941. ; 21:3, s. 389-400
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Journal article (peer-reviewed)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 time-derivative nature of GAA's scheme which tends to enhance all of these artifacts.
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| 10. |
- Kish, Laszlo B., et al.
(author)
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Comments On "A New Transient Attack On The Kish Key Distribution System"
- 2016
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In: METROLOGY AND MEASUREMENT SYSTEMS. - : Walter de Gruyter GmbH. - 0860-8229 .- 2300-1941. ; 23:3, s. 321-331
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Journal article (peer-reviewed)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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