1,720,964 research outputs found
Architectures and Design Methodologies for Micro and Nanocomputing
No full textFor many years, the transistors placement was not limited by interconnections thanks to the Digital Integrated Circuits market that is changing from a situation where CMOS technology was the reference (microelectronics era) to a plurality of emerging technologies (nanoelectronics era). The costs of optics photolithography needed to produce the recent CMOS technologies are increasing to such an extent as to make interesting the exploration of nanoelectronics alternative solutions. These technologies are called beyond CMOS technologies. Among the application fields, Information Security is one of the most pioneering rising market: several application areas need to ensure confidentiality and authenticity of data through cryptographic solutions. In some cases, cryptographic primitives can benefit a strong hardware acceleration. Unfortunately, CMOS based systems are vulnerable to ageing factors, such as Electromigration which decreases the reliability of certain security properties, and to Side-Channel attacks, where an attacker can retrieve confidential information by observing the power consumption. In this scenario, it is possible to speculate that emerging nanotechnologies can be exploited to cover the gaps left uncovered by CMOS technologies. A sub-class of circuits based on this novel techno- logical approach are called Dynamically-Coupled Systems (DCS). These novel technologies go beyond the transistor-interconnection dichotomy: elaboration, storage and transmission functions are all performed by the same device. DCS building blocks are called Processing Elements (PE). Interconnections are replaced with PE chains that are intrinsically pipelined. Ideally, it is possible to divide DCS technologies in two conventional sub-classes: Electrical-Coupled Technologies (ECT) where information propagation is due to electrons flow across ohmic paths and Field-Coupled Technologies (FCT). In FCT both the propagation and the elaboration of data depends on the electromagnetic field in- teractions (coupling) among PEs. An interesting possibility is offered by the use of single domain nanomagnets. Rectangular shaped magnets, with sizes smaller than 100nm, demonstrate a bistable behavior. This principle has been exploited to design digital logic circuits, leading to the so-called NanoMagnet Logic. The energy landscape of a single domain nanomagnet has two minimums corresponding to the magnetization vector aligned along the longer magnet side. If an ideal magnet is forced in the metastable state (i.e. the peak in the energy landscape), the probability that the magnet will reach one of the two stable states is exactly 0.5. The presented work proposes a plurality of development environments employable to study and design Dynamical-Coupled Nanocomputing digital circuits based on both a bottom-up approach for "fast prototyping" and a top-down one for complex circuits development environment. By means of the presented tools, it has been possible to study a series of Arithmetic and Cryptographic architectures, to perform circuit performance analysis and to highlight how the Modular Arithmetic offers a substantial contribution to the Field-Coupled Nanotechnologies interconnections overhead issue
Composite Fields against Side Channel Analysis for the Advanced Encryption Standard
No full textSecure implementations have two primary goals: being optimized (with respect to area, latency, power, or throughput) and secure against physical attacks, such as side channel analysis. Composite fields have been often proposed as a solution for the former problem, allowing implementations of the Advanced Encryption Standard targeted at resource constrained applications: additionally, they may also be a countermeasure against passive analysis and make an attack more difficult. In this paper, we present an AES design fully implemented on composite fields and evaluate its robustness against Differential Power Analysis
On the randomness of Field Coupled Nanomagnets
No full textWith the advancement of fabrication processes, single domain nanomagnets devices are being exploited to design digital logic circuits. In this work we evaluate the exploitability of nanomagnetic technologies to design cryptographic devices, such as True Random Number Generators and Physical Unclonable Functions. To quantify the source randomness we use the tests defined in NIST SP 800-22 [1] while for simulate the electronic devices we use micromagnetic simulations and Digital Signal Processing to reproduce circuit binary response
NANOcom: A Mosaic Approach for nanoelectronic circuits design
No full textIn this paper we present a tool, NANOcom, specifically developed for the bottom-up design and formalization of electronic circuits with a regular, matrix-like, structure. NANOcom allows to easily describe any kind of circuits and technologies where neighboring logic elements are dynamically coupled. Logic elements and interconnections are placed on a three-dimensional grid. Each element is characterized with an RTL model that describes its logic behavior and how it communicates with neighboring elements. Starting from the grid layout and the model, NANOcom automatically creates a VHDL code describing the whole structure. NANOcom can be used to simulate both standard CMOS circuits, such as PLAs, and new emerging technologies, like NASICs (Nanoscale Application Specific Integrated Circuits), memristor-based circuits and field coupled technologies, such as Nanomagnet Logic (NML), Quantum dot Cellular Automata (QCA) and Molecular QCA
Design of MRAM Based Magnetic Logic Circuits
No full textEmerging technologies are gaining an increasing at- tention due to the slowdown of CMOS development. NanoMagnet Logic, among emerging technologies, increases the potentials for developing fully magnetic circuits. Using a magnet as building block for logic circuits has the advantage to merge logic and mem- ory in the same device. Moreover circuits have low dynamic and no stand-by power consumption. Even though demonstrations exist for small circuits, the experimental feasibility of complex NML circuits still represents a critical point for this technology. In this work we outline the possibility to design NML circuits based on the technological structure of Magnetic RAMs. NML circuits based on MRAMs rely on a well developed technology that provides a natural interface with CMOS world. To study this new NML implementation a novel tool, NANOcom, was developed to easily design complex circuits. Simulations were then performed using an high level behavioral model described using VHDL language. Two types of circuit layouts, based on different technological constraints, are investigated. To evaluate the performance of this new NML implementation a 4-bit Galois multiplier is used as testbench. The Galois multiplier is the basic block of cryptographic circuits, an ideal target for this technology. Results obtained are encouraging and can unlock interesting options for the future development of NML technology
Side-channel analysis of SEcube™ platform
Full text linkCryptography provides techniques to cypher and de-cypher sensitive information through a token called key in order to store and transmit it across insecure networks. The goal of cryptography is to protect information from potential attackers and to enable access to authorized users only. Several hardware cryptographic devices are entering the market. However, these devices can be subject to passive attacks that consist in retrieving secret data by observing the side-channel behaviour of the device (i.e. execution time, power consumption, electromagnetic field). This work studies the robustness of SEcube™, an innovative secure hardware product against Differential Power Analysis attacks. SEcube™ is a system-on-chip equipped with three devices interconnected and embedded in a single chip: an ARM Cortex M4 low-power processor, a Lattice MachXO2-7000 FPGA and a SmartCard SLJ52G (EAL5+ certified). Moreover, in order to examine the security enhancement of this platform, we perform the same analysis with a similar board equipped with the same microprocessor and then compare the results. Experimental results show that the number of correct bits is similar between the two platform
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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