| 21. |
- Kish, Laszlo B., et al.
(författare)
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Random-Resistor-Random-Temperature Kirchhoff-Law-Johnson-Noise (RRRT-KLJN) Key Exchange
- 2016
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Ingår i: METROLOGY AND MEASUREMENT SYSTEMS. - : Walter de Gruyter GmbH. - 0860-8229 .- 2300-1941. ; 23:1, s. 3-11
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Tidskriftsartikel (refereegranskat)abstract
- We introduce two new Kirchhoff-law-Johnson-noise (KLJN) secure key distribution schemes which are generalizations of the original KLJN scheme. The first of these, the Random-Resistor (RR-) KLJN scheme, uses random resistors with values chosen from a quasi-continuum set. It is well-known since the creation of the KLJN concept that such a system could work in cryptography, because Alice and Bob can calculate the unknown resistance value from measurements, but the RR-KLJN system has not been addressed in prior publications since it was considered impractical. The reason for discussing it now is the second scheme, the Random Resistor Random Temperature (RRRT-) KLJN key exchange, inspired by a recent paper of Vadai, Mingesz and Gingl, wherein security was shown to be maintained at non-zero power flow. In the RRRT-KLJN secure key exchange scheme, both the resistances and their temperatures are continuum random variables. We prove that the security of the RRRT-KLJN scheme can prevail at a non-zero power flow, and thus the physical law guaranteeing security is not the Second Law of Thermodynamics but the Fluctuation-Dissipation Theorem. Alice and Bob know their own resistances and temperatures and can calculate the resistance and temperature values at the other end of the communication channel from measured voltage, current and power-flow data in the wire. However, Eve cannot determine these values because, for her, there are four unknown quantities while she can set up only three equations. The RRRT-KLJN scheme has several advantages and makes all former attacks on the KLJN scheme invalid or incomplete.
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| 22. |
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| 23. |
- Kish, Laszlo B., et al.
(författare)
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Unconditionally Secure Credit/Debit Card Chip Scheme and Physical Unclonable Function
- 2017
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Ingår i: Fluctuation and Noise Letters. - : WORLD SCIENTIFIC PUBL CO PTE LTD. - 0219-4775 .- 1793-6780. ; 16:1
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Tidskriftsartikel (refereegranskat)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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| 24. |
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| 25. |
- Kish, Laszlo B., et al.
(författare)
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Zero-point term and quantum effects in the Johnson noise of resistors : a critical appraisal
- 2016
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Ingår i: Journal of Statistical Mechanics. - : IOP Publishing. - 1742-5468 .- 1742-5468.
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Tidskriftsartikel (refereegranskat)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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| 26. |
- Kish, Laszlo B., et al.
(författare)
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Zero Thermal Noise in Resistors at Zero Temperature
- 2016
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Ingår i: Fluctuation and Noise Letters. - : World Scientific. - 0219-4775 .- 1793-6780. ; 15:3
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Tidskriftsartikel (refereegranskat)abstract
- The bandwidth of transistors in logic devices approaches the quantum limit, where Johnsonnoise and associated error rates are supposed to be strongly enhanced. However, the related theory — asserting a temperature-independent quantum zero-point (ZP) contribution to Johnson noise, which dominates the quantum regime — is controversial and resolution of the controversy is essential to determine the real error rate and fundamental energy dissipation limits of logic gates in the quantum limit. The Callen–Welton formula (fluctuation–dissipation theorem) of voltage and current noise for a resistance is the sum of Nyquist’s classical Johnson noise equation and a quantum ZP term with a power density spectrum proportional to frequency and independent of temperature. The classical Johnson–Nyquist formula vanishes at the approach of zero temperature, but the quantum ZP term still predicts non-zero noise voltage and current. Here, we show that this noise cannot be reconciled with the Fermi–Dirac distribution, which defines the thermodynamics of electrons according to quantum-statistical physics. Consequently,Johnson noise must be nil at zero temperature, and non-zero noise found for certain experimental arrangements may be a measurement artifact, such as the one mentioned in Kleen’s uncertainty relation argument.
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| 27. |
- Kwan, Chiman, et al.
(författare)
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Advanced agent identification with fluctuation-enhanced sensing
- 2008
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Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 8:5-6, s. 706-713
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Tidskriftsartikel (refereegranskat)abstract
- Conventional agent sensing methods normally use the steady state sensor values for agent classification. Many sensing elements (Hines et al., 1999, Ryan et al., 2004, Young et al.,, 2003, Qian et al., 2004, Qian et al.,, 2006, Carmel et ad., 2003) are needed in order to correctly classify multiple agents in mixtures. Fluctuation-enhanced sensing (FES) looks beyond the steady-state values and extracts agent information from spectra and bispectra. As a result, it is possible to use a single sensor to perform multiple agent classification. This paper summarizes the application of some advanced algorithms that can classify and estimate concentrations of different chemical agents. Our tool involves two steps. First, spectral and bispectral features will be extracted from the sensor signals. The features contain unique agent characteristics. Second, the features are fed into a hyperspectral signal processing algorithm for agent, classification and concentration estimation. The basic idea here is to use the spectral/bispectral shape information to perform agent classification. Extensive simulations have been performed by using simulated nanosensor data, as well as actual experimental data using commercial sensor (Taguchi). It was observed that our algorithms are able to accurately classify different agents, and also can estimate the concentration of the agents. Bispectra contain more information than spectra at the expense of high-computational costs. Specific nanostructured sensor model data yielded excellent performance because the agent responses are additive with this type of sensor. Moreover, for measured conventional sensor outputs, our algorithms also showed reasonable performance in terms of agent classification.
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| 28. |
- Lentka, Lukasz, et al.
(författare)
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DETERMINATION OF GAS MIXTURE COMPONENTS USING FLUCTUATION ENHANCED SENSING AND THE LS-SVM REGRESSION ALGORITHM
- 2015
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Ingår i: METROLOGY AND MEASUREMENT SYSTEMS. - : Walter de Gruyter GmbH. - 0860-8229 .- 2300-1941. ; XXII:3, s. 341-350
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Tidskriftsartikel (refereegranskat)abstract
- This paper analyses the effectiveness of determining gas concentrations by using a prototype WO3 resistive gas sensor together with fluctuation enhanced sensing. We have earlier demonstrated that this method can determine the composition of a gas mixture by using only a single sensor. In the present study, we apply Least-Squares Support-Vector-Machine-based (LS-SVM-based) nonlinear regression to determine the gas concentration of each constituent in a mixture. We confirmed that the accuracy of the estimated gas concentration could be significantly improved by applying temperature change and ultraviolet irradiation of the WO3 layer. Fluctuation-enhanced sensing allowed us to predict the concentration of both component gases.
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| 29. |
- Saez, Yessica, et al.
(författare)
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Current and voltage based bit errors and their combined mitigation for the Kirchhoff-law-Johnson-noise secure key exchange
- 2014
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Ingår i: Journal of Computational Electronics. - : Springer Science and Business Media LLC. - 1569-8025 .- 1572-8137. ; 13:1, s. 271-277
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Tidskriftsartikel (refereegranskat)abstract
- We classify and analyze bit errors in the current measurement mode of the Kirchhoff-law-Johnson-noise (KLJN) key distribution. The error probability decays exponentially with increasing bit exchange period and fixed bandwidth, which is similar to the error probability decay in the voltage measurement mode. We also analyze the combination of voltage and current modes for error removal. In this combination method, the error probability is still an exponential function that decays with the duration of the bit exchange period, but it has superior fidelity to the former schemes.
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| 30. |
- Schmera, Gabor, et al.
(författare)
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Separating Chemical Signals of Adsorption-Desorption and Diffusive Processes
- 2010
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Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 10:3, s. 461-464
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Tidskriftsartikel (refereegranskat)abstract
- We present a new sensor signal processing method that improves selectivity, sensitivity, and processing speed in systems, using fluctuation-enhanced sensing. We consider the output signal of a symmetric two-sensor arrangement and generate two independent output spectra by separating the adsorption-desorption signal component from the diffusion signal component. We demonstrate the key features of our method by computer modeling and simulation.
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