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

2017 ◽  
Vol 16 (03) ◽  
pp. 1750025 ◽  
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.

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

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.

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

2019 ◽  
Vol 19 (02) ◽  
pp. 2050012 ◽  
Author(s):  
Pao-Lo Liu
Keyword(s):  
Distribution System ◽  
Low Frequency ◽  
Key Distribution ◽  
Mutual Inductance ◽  
Circuit Model ◽  
Security Risk ◽  
Noise Sources ◽  
Band Limited ◽  
Complete Circuit ◽  
Two Sides

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.

scholarly journals Critical side channel effects in random bit generation with multiple semiconductor lasers in a polarization-based quantum key distribution system

2017 ◽  
Vol 25 (17) ◽  
pp. 20045 ◽  
Author(s):  
Heasin Ko ◽  
Byung-Seok Choi ◽  
Joong-Seon Choe ◽  
Kap-Joong Kim ◽  
Jong-Hoi Kim ◽  
...  
Keyword(s):  
Semiconductor Lasers ◽  
Distribution System ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Side Channel ◽  
Channel Effects

scholarly journals Demonstration of high-speed and low-complexity continuous variable quantum key distribution system with local local oscillator

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shengjun Ren ◽  
Shuai Yang ◽  
Adrian Wonfor ◽  
Ian White ◽  
Richard Penty
Keyword(s):  
Distribution System ◽  
Repetition Rate ◽  
Quantum Key Distribution ◽  
Optimization Technique ◽  
Key Distribution ◽  
Local Oscillator ◽  
Continuous Variable ◽  
Noise Model ◽  
System Level ◽  
Excess Noise

AbstractWe present an experimental demonstration of the feasibility of the first 20 + Mb/s Gaussian modulated coherent state continuous variable quantum key distribution system with a locally generated local oscillator at the receiver (LLO-CVQKD). To increase the signal repetition rate, and hence the potential secure key rate, we equip our system with high-performance, wideband devices and design the components to support high repetition rate operation. We have successfully trialed the signal repetition rate as high as 500 MHz. To reduce the system complexity and correct for any phase shift during transmission, reference pulses are interleaved with quantum signals at Alice. Customized monitoring software has been developed, allowing all parameters to be controlled in real-time without any physical setup modification. We introduce a system-level noise model analysis at high bandwidth and propose a new ‘combined-optimization’ technique to optimize system parameters simultaneously to high precision. We use the measured excess noise, to predict that the system is capable of realizing a record 26.9 Mb/s key generation in the asymptotic regime over a 15 km signal mode fibre. We further demonstrate the potential for an even faster implementation.

The Site Tilt and Lander Transfer Function from the Short-Period Seismometer of InSight on Mars

2021 ◽  
Author(s):  
Alexander E. Stott ◽  
Constantinos Charalambous ◽  
Tristram J. Warren ◽  
William T. Pike ◽  
Robert Myhill ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Dust Devils ◽  
Total Change ◽  
Noise Sources ◽  
Element Analysis ◽  
Near Surface ◽  
Seismic Experiment ◽  
Short Period ◽  
Sensitivity Changes

ABSTRACT The National Aeronautics and Space Administration InSight mission has deployed the seismic experiment, SEIS, on the surface of Mars, and has recorded a variety of signals including marsquakes and dust devils. This work presents results on the tilt and local noise sources, which provide context to aid interpretation of the observed signals and allow an examination of the near-surface properties. Our analysis uses data recorded by the short-period sensors on the deck, throughout deployment and in the final configuration. We use thermal decorrelation to provide an estimate of the sol-to-sol tilt. This tilt is examined across deployment and over a Martian year. After each modification to the site, the tilt is seen to stabilize over 3–20 sols depending on the action, and the total change in tilt is <0.035°. Long-term tilt over a Martian year is limited to <0.007°. We also investigate the attenuation of lander-induced vibrations between the lander and SEIS. Robotic arm motions provide a known lander source in the 5–9 Hz bandwidth, yielding an amplitude attenuation of lander signals between 100 and 1000 times. The attenuation of wind sensitivity from the deck to ground presents a similar value in the 1.5–9 Hz range, thus favoring a noise dominated by lander vibrations induced by the wind. Wind sensitivities outside this bandwidth exhibit different sensitivity changes, indicating a change in the coupling. The results are interpreted through a finite-element analysis of the regolith with a depth-dependent Young’s modulus. We argue that discrepancies between this model and the observations are due to local compaction beneath the lander legs and/or anelasticity. An estimate for the effective Young’s modulus is obtained as 62–81 MPa, corroborating previous estimates for the top layer duricrust.

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