IBM

Résumé

, connue sous le sigle IBM, est une entreprise multinationale américaine présente dans les domaines du matériel informatique, du logiciel et des services informatiques. La société est née le de la fusion de la Computing Scale Company et de la Tabulating Machine Company sous le nom de Computing Tabulating Recording Company (CTR). Celle-ci a changé de nom pour devenir International Business Machines Corporation le . On lui prête le surnom de Big Blue en référence au bleu sombre, couleur longtemps associée à l’entreprise. Dans les et les , IBM était la première capitalisation boursière au monde. Historique 1911 - 1929 Le , plusieurs entreprises ont été fusionnées par Charles Ranlett Flint, notamment l’International Time Recording Company et la Tabulating Machine Company pour former la Computing-Tabulating-Recording Company (C-T-R) ayant à son siège de New York. Flint recruta Thomas J. Watson, Senior. pour l’aider à diriger l’entreprise en 1914. Le , C-T-R fut r

Source officielle

https://fr.wikipedia.org/wiki/IBM

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Cours associés (19)

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Séances de cours associées (24)

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DES S-box generator

Lauren De Meyer, Serge Vaudenay

The Data Encryption Standard (DES) is a cryptographic algorithm, designed by IBM, that was selected to be the national standard in 1977 by the National Bureau of Standards. The algorithm itself was entirely published but the design criteria were kept secret until 1994 when Coppersmith, one of the designers of DES, published them. He states that the IBM team already knew about the attack called Differential cryptanalysis during the design of the algorithm and that it had an effect on choosing the S-boxes. To be more specific, he mentions eight design criteria that all the S-boxes of DES are based on. How the S-boxes were generated is a mystery, as the legend says this was outsourced to the NSA. Indeed, building a set of S-boxes respecting these criteria is a non-trivial task. In this paper we present an efficient S-box generator respecting all criteria and even more. Coppersmith's design criteria served as a basis but were strengthened for better resistance to Linear Cryptanalysis. While other researchers have already proposed S-box generators for DES satisfying either non-linearity or good diffusion, our generator offers both. Moreover, apart from suggesting a new set of 8 S-boxes, it can also very quickly produce a large pool of S-boxes to be used in further research.

Taylor & Francis Inc2016

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The authors discuss the results of a research project that developed an architectural framework for integrating non-IBM network architectures with the reference model and node structures of IBM's System Network Architecture (SNA). The unique features of the selected integration approach allow multiple protocol stacks to coexist and interoperate within the same computer, to share access to common physical network ports, links, and switching nodes, and to be accessed and managed through homogeneous interfaces. The architectural framework was developed for the specific purpose of integrating the open systems interconnection (OSI) reference model to that of SNA, but its basic philosophy and key aspects turn out to be generally applicable to the integration of other network technologies as well, e.g. TCP/IP or NETBIOS.

1991

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Intercomparison of Terrain-Following Coordinate Transformation and Immersed Boundary Methods for Large-Eddy Simulation of Wind Fields over Complex Terrain

Jiannong Fang, Fernando Porté Agel

We here perform an intercomparison of TFCT and IBM for large-eddy simulation of a turbulent wind field over a three-dimensional hill, for which wind-tunnel measurements are available for validation. The experimental dataset contains both vertical and horizontal profiles of mean velocities and variances, which allows an in-depth comparison of the numerical models. For the TFCT, a new algorithm for solving the pressure Poisson equation in the transformed coordinate system is proposed and first validated for a laminar flow over periodic two-dimensional hills by comparing with available benchmark solutions. Since the slopes of the three-dimensional hill are not steep, TFCT, which is free from implementation errors for the wall model, is preferable to IBM. The effects of sub-grid scale models and different schemes used to implement wall boundary conditions for IBM are studied. Discrepancies between the results obtained by TFCT and IBM are observed near the surface. The source of errors and possible ways to improve the IBM implementation are discussed.

2016

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