A Secure Hardware Implementation for Elliptic Curve Digital Signature Algorithm

Since the end of the 1990s, cryptosystems implemented on smart cards have had to deal with two main categories of attacks: side-channel attacks and fault injection attacks. Countermeasures have been developed and validated against these two types of attacks, taking into account a well-defined attacker model. This work focuses on small vulnerabilities and countermeasures related to the Elliptic Curve Digital Signature Algorithm (ECDSA) algorithm. The work done in this paper focuses on protecting the ECDSA algorithm against fault-injection attacks. More precisely, we are interested in the countermeasures of scalar multiplication in the body of the elliptic curves to protect against attacks concerning only a few bits of secret may be sufficient to recover the private key. ECDSA can be implemented in different ways, in software or via dedicated hardware or a mix of both. Many different architectures are therefore possible to implement an ECDSA-based system. For this reason, this work focuses mainly on the hardware implementation of the digital signature ECDSA. In addition, the proposed ECDSA architecture with and without fault detection for the scalar multiplication have been implemented on Xilinx field programmable gate arrays (FPGA) platform (Virtex-5). Our implementation results have been compared and discussed. Our area, frequency, area overhead and frequency degradation have been compared and it is shown that the proposed architecture of ECDSA with fault detection for the scalar multiplication allows a trade-off between the hardware overhead and the security of the ECDSA.     

New Trends in the Modeling of Diseases Through Computational Techniques

The computational techniques are a set of novel problem-solving methodologies that have attracted wider attention for their excellent performance. The handling strategies of real-world problems are artificial neural networks (ANN), evolutionary computing (EC), and many more. An estimated fifty thousand to ninety thousand new leishmaniasis cases occur annually, with only 25% to 45% reported to the World Health Organization (WHO). It remains one of the top parasitic diseases with outbreak and mortality potential. In 2020, more than ninety percent of new cases reported to World Health Organization (WHO) occurred in ten countries: Brazil, China, Ethiopia, Eritrea, India, Kenya, Somalia, South Sudan, Sudan, and Yemen. The transmission of visceral leishmaniasis is studied dynamically and numerically. The study included positivity, boundedness, equilibria, reproduction number, and local stability of the model in the dynamical analysis. Some detailed methods like Runge Kutta and Euler depend on time steps and violate the physical relevance of the disease. They produce negative and unbounded results, so in disease dynamics, such developments have no biological significance; in other words, these results are meaningless. But the implicit nonstandard finite difference method does not depend on time step, positive, bounded, dynamic and consistent. All the computational techniques and their results were compared using computer simulations.     

Stabilizing a class of nonlinear parameter-varying systems using interval observer based on a piecewise framework

This article addresses an interval observer-based control for stabilizing a class of nonlinear parameter-varying systems with noisy output by designing a switching surface. An input-dependent interval observer is firstly developed to estimate the lower and upper bounds of the states. Next, a switching-based controller is designed to stabilize the interval observer which implies the stability of the main parameter-varying system. The developed stabilizing switching surfaces are designed based on the outputs of the main system and the bounds of the states of the observer. By choosing an appropriate piecewise Lyapunov function, the closed-loop stability analysis of the interval observer system leads to a set of linear matrix inequalities including stability and Metzler constraints, simultaneously. The effectiveness of the proposed method is verified using the simulation results.     

Toward a web-based multi-criteria decision support system for the layered evaluation of interactive adaptive systems

Universal Access in the Information Society - The choice of suitable evaluation methods for the layered evaluation of Interactive Adaptive Systems (IAS) needs the consideration of different...     

High-Entropy Alloy-Induced Metallic Glass Transformation: Challenges Posed by in situ Alloying via Additive Manufacturing

In situ alloying and fabricating glassy structures through a layer-by-layer fashion approach are challenging but have high potential to develop novel-graded materials. For the first time, this cost-effective approach is applied to additive manufacturing (AM) of a Zr-based bulk metallic glass (BMG) from high-entropy alloys (HEAs). A newly developed composition of Zr₄₀Al₂₀Cu₂₀Ti₂₀ is fabricated through laser powder bed fusion (LPBF). Process parameters are optimized within a wide range of laser power (50–200 W) as well as scanning speed (50–800 mm s⁻¹). In all printed samples, microscopic and compositional examinations reveal no glass formation, but very fine grains and CuTi and AlTi nanocrystals. Some glassy transitions at the interfaces may be encouraged to occur with proper melting and mixing. However, the main reason for not obtaining a glassy matrix is the substantial proportion of unmelted Zr raw powder throughout the structure as spherical particles. Consequently, glass formation can be hindered by a considerable amount of compositional deviation. During LPBF, in situ alloying poses significant challenges to developing BMGs. Hence, the various stages of the process, including raw material specifications, laser settings, and process parameters, should be investigated further.     

Shared Cache Based on Content Addressable Memory in a Multi-Core Architecture

Modern shared-memory multi-core processors typically have shared Level 2 (L2) or Level 3 (L3) caches. Cache bottlenecks and replacement strategies are the main problems of such architectures, where multiple cores try to access the shared cache simultaneously. The main problem in improving memory performance is the shared cache architecture and cache replacement. This paper documents the implementation of a Dual-Port Content Addressable Memory (DPCAM) and a modified Near-Far Access Replacement Algorithm (NFRA), which was previously proposed as a shared L2 cache layer in a multi-core processor. Standard Performance Evaluation Corporation (SPEC) Central Processing Unit (CPU) 2006 benchmark workloads are used to evaluate the benefit of the shared L2 cache layer. Results show improved performance of the multicore processor’s DPCAM and NFRA algorithms, corresponding to a higher number of concurrent accesses to shared memory. The new architecture significantly increases system throughput and records performance improvements of up to 8.7% on various types of SPEC 2006 benchmarks. The miss rate is also improved by about 13%, with some exceptions in the sphinx3 and bzip2 benchmarks. These results could open a new window for solving the long-standing problems with shared cache in multi-core processors.     

Analysing Various Control Technics for Manipulator Robotic System (Robogymnast)

The Robogymnast is a highly complex, three-link system basedon the triple-inverted pendulum and is modelled on the human example ofa gymnast suspended by their hands from the high bar and executing largerand larger upswings to eventually rotate fully. The links of the Robogymnastcorrespond respectively to the arms, trunk, and lower limbs of the gymnast,and from its three joints, one is under passive operation, while the remainingtwo are powered. The passive top joint poses severe challenges in attainingthe smooth movement control needed to operate the Robogymnast effectively.This study assesses four types of controllers used for systems operation andidentifies how far response stabilisation is achieved with each. The system issimulated using MATLAB Simulink, with findings generated regarding risingand settling time, as well as overshoot. The research primarily seeks to examine the application of a linear quadratic regulator controller, proportionalintegral-derivative controller, fuzzy linear quadratic regulator controller andlinear quadratic regulator- proportional-integral-derivative controller for thistype of system and comparisons between the different controllers to demonstrate successful performance, which highlights the claimed advantages of theproposed system.     

Thermally enhanced dislocation density improves both hardness and fracture toughness in single-crystal SrTiO3

Dislocation-tuned functionality in ceramic oxides for potential versatile applications gains increasing attention. As the widespread chemical doping suffers from poor temperature stability, dislocations in well-controlled mesoscopic structure may be an alternative to thermally stable intrinsic doping features. To this end, the dislocation density in plastic zones introduced by cyclic Brinell indentation is considered under thermal annealing conditions. The considerably enhanced dislocation density due to thermal treatment is found to impact both microhardness and fracture toughness, albeit only to a modest degree. The mechanistic understanding centers around enhanced mobility and multiplication of the pre-engineered dislocations at elevated temperatures driven by the residual indentation stress, as well as the strengthened interaction of point defects and dislocations at high temperature.     

New strategies for surface modification of poly (vinyl alcohol) toward click chemistry applications

In this study, new synthesis strategies for poly (vinyl alcohol) (PVA) functionalized with azidation (Az) and alkynation (Alk) were carried out for surface functionality modification. These two functionalization routes utilize azide and alkyne groups, respectively, and offer simple way to enhance the PVA crosslinking capabilities toward producing new functional polymer-based materials. The Az functionalized PVA was prepared in two steps and denoted by PVA-Az, while Alk functionalized PVA was prepared in one step to produce PVA-Alk. Surfaces modification of PVA by using Az and Alk functional groups was confirmed by spectral analysis (Fourier transform infrared and ¹³C-NMR). Results showed that Alk prompted excellent chemical modifications on the surface of PVA while the thermal stability was enhanced by functionalizing the Az and Alk into PVA. Furthermore, X-ray photoelectron spectroscopy investigations showed a successful functionalization and new functional groups addition to PVA surface. Scanning electron microscope images were used to analyze the surface morphology of PVA by incorporating the Az and Alk groups, which indicated rougher surfaces compared to that of PVA backbone. In terms of efficiency and simplicity, the techniques used in this study appear to be entirely satisfactory.