Software Evaluation for Second Round Candidates in NIST Lightweight Cryptography

Lightweight cryptography algorithms are increasing in value because they can enhance security under limited resources. National Institute of Standards and Technology is working on standardising lightweight authenticated encryption with associated data. Thirty-two candidates are included in the second round of the NIST selection process, and their specifications differ with respect to various points. Therefore, for each algorithm, the differences in specifications are expected to affect the algorithm\u27s performance. This study aims to facilitate the selection and design of those algorithms according to the usage scenarios. For this purpose, we investigate and compare the 32 lightweight cryptography algorithm candidates using specifications and software implementations. The results indicate that latency and memory usage depend on parameters and nonlinear operations. In terms of memory usage, a difference exists in ROM usage, but not in the RAM usage from our experiments using ARM platform. We also discovered that the data size to be processed efficiently differs according to the padding scheme, mode of operation, and block size

Fabrication and Characterization of SiC-Hybridized Carbon Fibre Reinforced Aluminium Matrix ComPosites

Carbon fibre reinforced aluminium matrix (CF/Al) composites were fabricated with a hybridization technology through pressure casting and characterization of the hybrid composites obtained was carried out. Hybridization with SiC additive could improve the infiltration performance of fibre preform, control the fibre volume fraction, and increase the fibre-strength transfer efficiency of the hybrid composites. The longitudinal tensile strength of the hybrid composites was greatly improved compared with that of the conventional composite. It was found that the strength deterioration of high-modulus cab on fibres (HMCFs) during fabrication was not heavy and depended upon the type of aluminium matrix, while the strength of high-strength carbon fibres (HSCFs) was greatly reduced by aluminium matrix, but the degradation did not depend on the variety of the matrix. As a result, the longitudinal tensile strength of hybrid HMCF/Al composites was higher than 800 MPa, while that of hybrid HSCF/Al composites was about 400 MPa. Contrariwise, the transverse tensile strength of hybrid HSCF/Al composites was much greater than that of hybrid HMCF/Al composites. The results of thermal exposure of hybrid HMCF/Al-Si composites at 773 K showed that their longitudinal tensile strength increased, then decreased, while their transverse tensile strength increased montonically, as the exposure was proceeded. The thermal exposure slightly reduced fibre strength, caused chemical interactions, and resulted in changes of fracture morphology and fibre pull-out length of the composites. It was also concluded that fibre/matrix interfacial bonding has an important effect on the mechanical properties of CF/Al composites and intermediate interfacial bonding can be expected to result in good longitudinal and transverse tensile strengths of CF/Al composites

Active auroral arc powered by accelerated electrons from very high altitudes

オーロラ粒子の加速領域が超高高度まで広がっていたことを解明 －オーロラ粒子の加速の定説を覆す発見－. 京都大学プレスリリース. 2021-01-20.Bright, discrete, thin auroral arcs are a typical form of auroras in nightside polar regions. Their light is produced by magnetospheric electrons, accelerated downward to obtain energies of several kilo electron volts by a quasi-static electric field. These electrons collide with and excite thermosphere atoms to higher energy states at altitude of ~ 100 km; relaxation from these states produces the auroral light. The electric potential accelerating the aurora-producing electrons has been reported to lie immediately above the ionosphere, at a few altitudes of thousand kilometres1. However, the highest altitude at which the precipitating electron is accelerated by the parallel potential drop is still unclear. Here, we show that active auroral arcs are powered by electrons accelerated at altitudes reaching greater than 30, 000 km. We employ high-angular resolution electron observations achieved by the Arase satellite in the magnetosphere and optical observations of the aurora from a ground-based all-sky imager. Our observations of electron properties and dynamics resemble those of electron potential acceleration reported from low-altitude satellites except that the acceleration region is much higher than previously assumed. This shows that the dominant auroral acceleration region can extend far above a few thousand kilometres, well within the magnetospheric plasma proper, suggesting formation of the acceleration region by some unknown magnetospheric mechanisms

On the Non-equilibrium Thermodynamics

この論文は国立情報学研究所の電子図書館事業により電子化されました。研究会報

A note on Description of Hydrodyanmic Fluctuation by a Master Equation

この論文は国立情報学研究所の電子図書館事業により電子化されました

Contribution to the theory of fluctuations in non-linear systems

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe