The Notion of Transparency Order, Revisited

We revisit the definition of Transparency Order (TO) and that of Modified Transparency Order (MTO) as well, which were proposed to measure the resistance of an S-box against Differential Power Analysis (DPA). We spot a definitional flaw in original TO, which is proved to have significantly affected the soundness of TO and hinder it to be a good quantitative security criterion. Regretfully, the flaw itself remains virtually undiscovered in MTO, either. Surprisingly, MTO overlooks this flaw and yet it happens to incur no bad effects on the correctness of its formulation, even though the start point of this formulation is highly questionable. It is also this neglect of the flaw that made MTO take a variant of multi-bit DPA attack into consideration, which was mistakenly thought to appropriately serve as an alternative powerful attack. Based on this observation, we also find that MTO introduces such an alternative adversary that it might overestimate the resistance of an S-box in some cases, as the variant of multi-bit DPA attack considered in MTO is not that powerful as one may think. This implies the soundness of MTO is also more or less arguable. Consequently, we fix this definitional flaw, and provide a revised definition in which a powerful adversary is also involved. For demonstrating validity and soundness of our revised TO (RTO), we adopt both optimal $4\times4$ S-boxes and $8\times8$ S-boxes as study cases, and present simulated and practical DPA attacks as well on implementations of those S-boxes. The results of our attacks verify our findings and analysis as well. Furthermore, as a concrete application of the revised TO, we also present the distribution of RTO values for sixteen optimal affine equivalence classes of $4\times4$ S-boxes. Finally, we give some recommended guidelines on how to select optimal $4\times4$ S-boxes in practical implementations

Redefining the Transparency Order

International audience4 Agence nationale de la scurit des systmes d'information (ANSSI) Abstract. In this paper, we revisit the definition of Transparency Order (TO) from the work of Prouff (FSE 2005) that was proposed to measure the resistance of an s-box against Differential Power Analysis. We find that the definition has certain limitations. Although this work has been quite well referred in the literature, surprisingly, these limitations remained unexplored for almost a decade. We analyze the definition from scratch, modify it and finally provide a revised definition. Our simulation results confirm that the transparency order is indeed related to the resistance of the s-box against side-channel attacks. Thus (revised) TO is one of the valuable criteria to consider when designing a cryptographic algorithm

Chandra News

The Chandra Newsletter contains articles about the CXC and the Chandra mission. The Chandra Newsletter appears once a year and is edited by Paul J. Green, with editorial assistance and layout by Evan Tingle. We welcome contributions from readers. Comments on the newsletter, or corrections and additions to the hardcopy mailing list should be sent to: [email protected]

Superconductor

This book contains a collection of works intended to study theoretical and experimental aspects of superconductivity. Here you will find interesting reports on low-Tc superconductors (materials with Tc 30 K). Certainly this book will be useful to encourage further experimental and theoretical researches in superconducting materials

IFMIF - International Fusion Materials Irradiation Facility Conceptual Design Activity/Interim Report

Environmental acceptability, safety, and economic viability win ultimately be the keys to the widespread introduction of fusion power. This will entail the development of radiation- resistant and low- activation materials. These low-activation materials must also survive exposure to damage from neutrons having an energy spectrum peaked near 14 MeV with annual radiation doses in the range of 20 displacements per atom (dpa). Testing of candidate materials, therefore, requires a high-flux source of high energy neutrons. The problem is that there is currently no high-flux source of neutrons in the energy range above a few MeV. The goal, is therefore, to provide an irradiation facility for use by fusion material scientists in the search for low-activation and damage-resistant materials. An accellerator-based neutron source has been established through a number of international studies and workshops` as an essential step for materials development and testing. The mission of the International Fusion Materials Irradiation Facility (IFMIF) is to provide an accelerator-based, deuterium-lithium (D-Li) neutron source to produce high energy neutrons at sufficient intensity and irradiation volume to test samples of candidate materials up to about a full lifetime of anticipated use in fusion energy reactors. would also provide calibration and validation of data from fission reactor and other accelerator-based irradiation tests. It would generate material- specific activation and radiological properties data, and support the analysis of materials for use in safety, maintenance, recycling, decommissioning, and waste disposal systems

Simulación de la evolución de defectos en materiales irradiados de interés en fusión nuclear mediante un método GPU-OKMC

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Físicas, leída el 28-11-2022As the current world reliance on fossil fuels proves to have catastrophic environmental consequences, which are only exacerbated with a growing world economy and population, a future clean source of energy is required. The scientific community expects nuclear fusion to fulfill this task, in particular magnetically confined fusion. To achieve this, an experimental fusion reactor, the ITER Project, is underway and shall provide the basis for a future demonstration power plant, known as DEMO. One of the most important challenges in the design of a future nuclear fusion reactor is the choice of materials. Materials are subjected to an intense flux of neutrons and heat in a fusion reactor like ITER or, in a much more pronounced way, DEMO. Under irradiation, a large amount of defects are created and, as aconsequence, the properties of materials are severely degraded, and may cause the reactor components to malfunction or break...Dado que la actual dependencia mundial de los combustibles fósiles muestra ciertas consecuencias catastro cas para el medio ambiente, las cuales son magnificadas a medida que crecen la economía y población mundiales, se necesita una fuente de energía limpia para el futuro. La comunidad científica espera que sea la fusión nuclear la que desempeñe este papel, en particular la fusión por confinamiento magnético. Para ello, un reactor de fusión experimental, el Proyecto ITER, esta en marcha y proporcionará las bases para un futuro reactor de demostración llamado DEMO. Uno de los desafíos principales en el diseño de un futuro reactor de fusión es la elección de los materiales. En efecto, los materiales serán sometidos a un flujo intenso de neutrones y calor en un reactor de fusión como ITER; y, de forma más pronunciada, en uno como DEMO. Esto provocara la creación de una gran cantidad de defectos, por lo que las propiedades de los materiales serán gravemente alteradas, y podrán provocar que los componentes del reactor dejen de funcionar correctamente o, incluso, se quiebren...Fac. de Ciencias FísicasTRUEunpu