Trade-Off Approach for GHASH Computation Based on a Block-Merging Strategy

In the Galois counter mode (GCM) of encryption an authentication tag is computed with a sequence of multiplications and additions in F 2 m. In this paper we focus on multiply-and-add architecture with a suquadratic space complexity multiplier in F 2 m. We propose a recom-bination of the architecture of P. Patel (Master Thesis, U. Waterloo, ON. Canada, 2008) which is based on a subquadratic space complexity Toeplitz matrix vector product. We merge some blocks of the recombined architecture in order to reduce the critical path delay. We obtain an architecture with a subquadratic space complexity of O(log 2 (m)m log 2 (m)) and a reduced delay of (1.59 log 2 (m) + log 2 (δ))D X + D A where δ is a small constant. To the best of our knowledge, this is the first multiply-and-add architecture with subquadratic space complexity and delay smaller than 2 log 2 (m)D X

Efficient Regular Scalar Multiplication on the Jacobian of Hyperelliptic Curve over Prime Field Based on Divisor Splitting

We consider in this paper scalar multiplication algorithms over a hyperelliptic curve which are immune against simple power analysis and timing attack. To reach this goal we adapt the regular modular exponentiation based on multiplicative splitting presented in JCEN 2017 to scalar multiplication over a hyperelliptic curve. For hyperelliptic curves of genus g = 2 and 3, we provide an algorithm to split the base divisor as a sum of two divisors with smaller degree. Then we obtain an algorithm with a regular sequence of doubling always followed by an addition with a low degree divisor. We also provide efficient formulas to add such low degree divisors with a divisor of degree g. A complexity analysis and implementation results show that the proposed approach is better than the classical Double-and-add-always approach for scalar multiplication

Efficient randomized regular modular exponentiation using combined Montgomery and Barrett multiplications

Copyright 2016 by SCITEPRESS - Science and Technology Publications, Lda. All rights reserved.Cryptographic operations performed on an embedded device are vulnerable to side channel analysis and particularly to differential and correlation power analysis. The basic protection against such attacks is to randomize the data all along the cryptographic computations. In this paper we present a modular multiplication algorithm which can be used for randomization. We show that we can use it to randomize the modular exponentiation of the RSA cryptosystem. The proposed randomization is free of computation and induces a level of randomization from 210 to 215 for practical RSA modulus size

Multiplication in Finite Fields and Elliptic Curves

La cryptographie à clef publique permet de s'échanger des clefs de façon distante, d'effectuer des signatures électroniques, de s'authentifier à distance, etc. Dans cette thèse d'HDR nous allons présenter quelques contributions concernant l'implantation sûre et efficace de protocoles cryptographiques basés sur les courbes elliptiques. L'opération de base effectuée dans ces protocoles est la multiplication scalaire d'un point de la courbe. Chaque multiplication scalaire nécessite plusieurs milliers d'opérations dans un corps fini.Dans la première partie du manuscrit nous nous intéressons à la multiplication dans les corps finis car c'est l'opération la plus coûteuse et la plus utilisée. Nous présentons d'abord des contributions sur les multiplieurs parallèles dans les corps binaires. Un premier résultat concerne l'approche sous-quadratique dans une base normale optimale de type 2. Plus précisément, nous améliorons un multiplieur basé sur un produit de matrice de Toeplitz avec un vecteur en utilisant une recombinaison des blocs qui supprime certains calculs redondants. Nous présentons aussi un multiplieur pous les corps binaires basé sur une extension d'une optimisation de la multiplication polynomiale de Karatsuba.Ensuite nous présentons des résultats concernant la multiplication dans un corps premier. Nous présentons en particulier une approche de type Montgomery pour la multiplication dans une base adaptée à l'arithmétique modulaire. Cette approche cible la multiplication modulo un premier aléatoire. Nous présentons alors une méthode pour la multiplication dans des corps utilisés dans la cryptographie sur les couplages : les extensions de petits degrés d'un corps premier aléatoire. Cette méthode utilise une base adaptée engendrée par une racine de l'unité facilitant la multiplication polynomiale basée sur la FFT. Dans la dernière partie de cette thèse d'HDR nous nous intéressons à des résultats qui concernent la multiplication scalaire sur les courbes elliptiques. Nous présentons une parallélisation de l'échelle binaire de Montgomery dans le cas de E(GF(2^n)). Nous survolons aussi quelques contributions sur des formules de division par 3 dans E(GF(3^n)) et une parallélisation de type (third,triple)-and-add. Dans le dernier chapitre nous développons quelques directions de recherches futures. Nous discutons d'abord de possibles extensions des travaux faits sur les corps binaires. Nous présentons aussi des axes de recherche liés à la randomisation de l'arithmétique qui permet une protection contre les attaques matérielles

InfraPhenoGrid: A scientific workflow infrastructure for Plant Phenomics on the Grid

International audiencePlant phenotyping consists in the observation of physical and biochemical traits of plant genotypes in response to environmental conditions. Challenges , in particular in context of climate change and food security, are numerous. High-throughput platforms have been introduced to observe the dynamic growth of a large number of plants in different environmental conditions. Instead of considering a few genotypes at a time (as it is the case when phenomic traits are measured manually), such platforms make it possible to use completely new kinds of approaches. However, the data sets produced by such widely instrumented platforms are huge, constantly augmenting and produced by increasingly complex experiments, reaching a point where distributed computation is mandatory to extract knowledge from data. In this paper, we introduce InfraPhenoGrid, the infrastructure we designed and deploy to efficiently manage data sets produced by the PhenoArch plant phenomics platform in the context of the French Phenome Project. Our solution consists in deploying scientific workflows on a Grid using a middle-ware to pilot workflow executions. Our approach is user-friendly in the sense that despite the intrinsic complexity of the infrastructure, running scientific workflows and understanding results obtained (using provenance information) is kept as simple as possible for end-users

Lipid-Induced Peroxidation in the Intestine Is Involved in Glucose Homeostasis Imbalance in Mice

BACKGROUND: Daily variations in lipid concentrations in both gut lumen and blood are detected by specific sensors located in the gastrointestinal tract and in specialized central areas. Deregulation of the lipid sensors could be partly involved in the dysfunction of glucose homeostasis. The study aimed at comparing the effect of Medialipid (ML) overload on insulin secretion and sensitivity when administered either through the intestine or the carotid artery in mice. METHODOLOGY/PRINCIPAL FINDINGS: An indwelling intragastric or intracarotid catheter was installed in mice and ML or an isocaloric solution was infused over 24 hours. Glucose and insulin tolerance and vagus nerve activity were assessed. Some mice were treated daily for one week with the anti-lipid peroxidation agent aminoguanidine prior to the infusions and tests. The intestinal but not the intracarotid infusion of ML led to glucose and insulin intolerance when compared with controls. The intestinal ML overload induced lipid accumulation and increased lipid peroxidation as assessed by increased malondialdehyde production within both jejunum and duodenum. These effects were associated with the concomitant deregulation of vagus nerve. Administration of aminoguanidine protected against the effects of lipid overload and normalized glucose homeostasis and vagus nerve activity. CONCLUSIONS/SIGNIFICANCE: Lipid overload within the intestine led to deregulation of gastrointestinal lipid sensing that in turn impaired glucose homeostasis through changes in autonomic nervous system activity

Subquadratic binary field multiplier in double polynomial system

We propose a new space efficient operator to multiply elements lying in a binary field F2k . Our approach is based on a novel system of representation called Double Polynomial System which set elements as a bivariate polynomials over F2. Thanks to this system of representation, we are able to use a Lagrange representation of the polynomials and then get a logarithmic time multiplier with a space complexity of O(k1:31) improving previous best known method

Etat de l'Art de l'Arithmétique des Corps Finis

Etat de l'Art de l'Arithmétique des Corps Fini