A Complete Circuit Model for the Key Distribution System Using Resistors and Noise Sources

A complete circuit model is developed for modeling the classical key distribution system based on resistors and band-limited noise sources. Theoretical analysis provides component values, including the mutual inductance. Circuit simulations are performed to obtain voltage and current as a function of frequency. Any imbalance between two sides of the communications link is identified. Results indicate that the current, especially, in the bootstrapping circuit, can be a potential security risk unless all signals are band-limited to a low frequency.

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Uniformly Bootstrapped Cable for the Key Distribution System Using Resistors and Noise Sources

Fluctuation and Noise Letters ◽

10.1142/s0219477520500467 ◽

2020 ◽

Vol 19 (04) ◽

pp. 2050046

Author(s):

Pao-Lo Liu

Keyword(s):

Transmission Line ◽

Distribution System ◽

Characteristic Impedance ◽

Key Distribution ◽

Mutual Inductance ◽

Noise Sources ◽

Lumped Element

Waveguide analysis indicates that a triaxial cable with uniform bootstrapping is a transmission line with an adjustable characteristic impedance. When the bootstrapping level is high, the characteristic impedance is high. The cable capacitance is reduced while the cable inductance is increased. Simulations confirm that the transmission-line circuit and the lumped-element circuit, including the mutual inductance, generate the same results for the key distribution system using resistors and noise sources.

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Re-Examination of the Cable Capacitance in the Key Distribution System Using Resistors and Noise Sources

Fluctuation and Noise Letters ◽

10.1142/s0219477517500250 ◽

2017 ◽

Vol 16 (03) ◽

pp. 1750025 ◽

Cited By ~ 3

Author(s):

Pao-Lo Liu

Keyword(s):

Transmission Line ◽

Transit Time ◽

Distribution System ◽

Key Distribution ◽

Noise Sources ◽

Element Analysis ◽

Lumped Element ◽

Band Limited ◽

Line Analysis

The effect of cable capacitance in the classical key distribution system based on resistors and band-limited noise sources is re-examined. Both the lumped element analysis and the transmission line analysis are performed. As long as the cable capacitance and inductance are fully taken into account, the lumped element analysis and the transmission line analysis generate identical results. When the cable is bootstrapped with a driven shield, the capacitance can be neglected, but the transit time should not be overlooked.

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Real-time low-frequency vibration phase drift tracking and auto-compensation in phase-coded quantum key distribution system

Acta Physica Sinica ◽

10.7498/aps.56.3695 ◽

2007 ◽

Vol 56 (7) ◽

pp. 3695

Author(s):

Guo Bang-Hong ◽

Lu Yi-Qun ◽

Wang Fa-Qiang ◽

Zhao Feng ◽

Hu Min ◽

...

Keyword(s):

Real Time ◽

Distribution System ◽

Quantum Key Distribution ◽

Low Frequency ◽

Key Distribution ◽

Phase Drift ◽

Low Frequency Vibration

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A Novel Key Distribution Scheme Based on Transmission Delays

Security and Communication Networks ◽

10.1155/2021/3125820 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Jie Huang ◽

Xiaowen Wang ◽

Wei Wang ◽

Zhenyu Duan

Keyword(s):

Distribution System ◽

Formal Analysis ◽

Key Distribution ◽

Transmission Delay ◽

Statistical Characteristics ◽

The Internet ◽

Transmission Delays ◽

Distribution Scheme ◽

Two Sides ◽

Day By Day

With the development of IoT (Internet of Things), the demand for security is increasing day by day. However, the traditional key distribution scheme is high in cost and complicated in calculation, so a lightweight key distribution scheme is urgently needed. In this paper, a novel key distribution scheme based on transmission delay is proposed. Based on the experimental observation, we find that the statistical characteristics of their transmission delays are about the same if any two terminals transmit the equal-length packets on the Internet and are different for different transmission paths. Accordingly, we propose a method to customize transmission delays. On the Internet, we have deployed 7 forwarding hosts. By randomly determining the forwarding path of packets, we can get customized transmission delay sets. Then, these sets are processed, respectively, by correcting outlier, normalizing, quantizing, encoding, and reconciling so as to be able to realize key distribution between two sides. Next, we design a key distribution protocol and a key distribution system, which consists of a Management Center, a Packet Forwarding Network, and Users. Finally, we reason the security of the key distribution protocol with formal analysis tools.

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Noise source location and scaling of subsonic upper-surface blowing

International Journal of Aeroacoustics ◽

10.1177/1475472x20930652 ◽

2020 ◽

Vol 19 (3-5) ◽

pp. 191-206

Author(s):

Trae L Jennette ◽

Krish K Ahuja

Keyword(s):

Strouhal Number ◽

Noise Source ◽

Low Frequency ◽

Directivity Pattern ◽

Source Location ◽

Dipole Source ◽

Frequency Noise ◽

Noise Sources ◽

Trailing Edge ◽

Trailing Edge Noise

This paper deals with the topic of upper surface blowing noise. Using a model-scale rectangular nozzle of an aspect ratio of 10 and a sharp trailing edge, detailed noise contours were acquired with and without a subsonic jet blowing over a flat surface to determine the noise source location as a function of frequency. Additionally, velocity scaling of the upper surface blowing noise was carried out. It was found that the upper surface blowing increases the noise significantly. This is a result of both the trailing edge noise and turbulence downstream of the trailing edge, referred to as wake noise in the paper. It was found that low-frequency noise with a peak Strouhal number of 0.02 originates from the trailing edge whereas the high-frequency noise with the peak in the vicinity of Strouhal number of 0.2 originates near the nozzle exit. Low frequency (low Strouhal number) follows a velocity scaling corresponding to a dipole source where as the high Strouhal numbers as quadrupole sources. The culmination of these two effects is a cardioid-shaped directivity pattern. On the shielded side, the most dominant noise sources were at the trailing edge and in the near wake. The trailing edge mounting geometry also created anomalous acoustic diffraction indicating that not only is the geometry of the edge itself important, but also all geometry near the trailing edge.

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Low-Frequency Signal Sampling Method Implemented in a PLC Controller Dedicated to Applications in the Monitoring of Selected Electrical Devices

Electronics ◽

10.3390/electronics10040442 ◽

2021 ◽

Vol 10 (4) ◽

pp. 442

Author(s):

Marcin Jaraczewski ◽

Ryszard Mielnik ◽

Tomasz Gębarowski ◽

Maciej Sułowicz

Keyword(s):

Power System ◽

Reactive Power ◽

Low Frequency ◽

Sampling Frequency ◽

Electrical Signal ◽

Distortion Factor ◽

Electrical Devices ◽

Frequency Sampling ◽

Sampled Signal ◽

Band Limited

High requirements for power systems, and hence for electrical devices used in industrial processes, make it necessary to ensure adequate power quality. The main parameters of the power system include the rms-values of the current, voltage, and active and reactive power consumed by the loads. In previous articles, the authors investigated the use of low-frequency sampling to measure these parameters of the power system, showing that the method can be easily implemented in simple microcontrollers and PLCs. This article discusses the methods of measuring electrical quantities by devices with low computational efficiency and low sampling frequency up to 1 kHz. It is not obvious that the signal of 50–500 Hz can be processed using the sampling frequency of fs = 47.619 Hz because it defies the Nyquist–Shannon sampling theorem. This theorem states that a reconstruction of a sampled signal is only guaranteed possible for a bandlimit fmax < fs, where fmax is the maximum frequency of a sampled signal. Therefore, theoretically, neither 50 nor 500 Hz can be identified by such a low-frequency sampling. Although, it turns out that if we have a longer period of a stable multi-harmonic signal, which is band-limited (from the bottom and top), it allows us to map this band to the lower frequencies, thus it is possible to use the lower sampling ratio and still get enough precise information of its harmonics and rms value. The use of aliasing for measurement purposes is not often used because it is considered a harmful phenomenon. In our work, it has been used for measurement purposes with good results. The main advantage of this new method is that it achieves a balance between PLC processing power (which is moderate or low) and accuracy in calculating the most important electrical signal indicators such as power, RMS value and sinusoidal-signal distortion factor (e.g., THD). It can be achieved despite an aliasing effect that causes different frequencies to become indistinguishable. The result of the research is a proposal of error reduction in the low-frequency measurement method implemented on compact PLCs. Laboratory tests carried out on a Mitsubishi FX5 compact PLC controller confirmed the correctness of the proposed method of reducing the measurement error.

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