Pandora : une plate-forme efficace pour la construction d'applications autonomes

Autonomic computing has been proposed recently as a way to address the difficult management of applications whose complexity is constantly increasing. Autonomous applications will have to be especially flexible and be able to monitor themselves permanently. This work presents a framework, Pandora, which eases the construction of applications that satisfy this double goal. Pandora relies on an original application programming pattern - based on stackable layers and message passing - to obtain minimalist model and architecture that allows to control the overhead imposed by the full reflexivity of the framework. Besides, a prototype of the framework has been implemented in C++. A detailed performance study, together with examples of use, complement this presentatio

QUAD: Overview and Recent Developments

We give an outline of the specification and provable security features of the QUAD stream cipher proposed at Eurocrypt 2006. The cipher relies on the iteration of a multivariate system of quadratic equations over a finite field, typically GF(2) or a small extension. In the binary case, the security of the keystream generation can be related, in the concrete security model, to the conjectured intractability of the MQ problem of solving a random system of m equations in n unknowns. We show that this security reduction can be extended to incorporate the key and IV setup and provide a security argument related to the whole stream cipher.We also briefly address software and hardware performance issues and show that if one is willing to pseudorandomly generate the systems of quadratic polynomials underlying the cipher, this leads to suprisingly inexpensive hardware implementations of QUAD

Pandora : un système de collecte de traces du trafic Web de communautés d'utilisateurs réparties

Projet SORPandora permet de collecter les informations nécessaires pour caractériser le trafic Web d'une communauté d'utilisateurs répartie. Les informations sont obtenues en reconstituant le trafic HTTP directement à partir des paquets réseau. Sur le plan architectural, Pandora est constitué de trois composants logiciels coopérants : un collecteur, un observateur et un coordinateur, qui peuvent être déployés en différents points du réseau. En interne, chaque composant est implémenté par une série de filtres. Cette architecture autorise une grande souplesse d'utilisation et de déploieme- nt. Les traces fournies par Pandora donnent des informations détaillées sur les profils des utilisateurs, les serveurs, les documents accédés, le réseau et les caches. Elles peuvent être utilisées pour déterminer la politique de cache ou de réplication qui offre la meilleure qualité de service possible aux utilisateurs

Transfinite Cryptography

\begin{abstract} Let assume that Alice, Bob, and Charlie, the three classical people of cryptography are not limited anymore to perform a finite number of computations on real computers, but are limited to $\alpha$ computations and to $\alpha$ bits of memory, where $\alpha$ is a fixed infinite cardinal. For example $\alpha = \aleph _0$ (the countable cardinal, i.e. the cardinal of $\mathbb {N}$ the set of integers), or $\alpha = \mathfrak {C}$ (the cardinal of the set $\mathbb {R}$ of real numbers). Is it possible to do secret key cryptography? Public key cryptography? Encryption? Authentication? Signatures? Is it possible to generalize the notion of one way function? The aim of this paper is to give some elements of answers to these questions. We will see for example that for secret key cryptography there are some simple solutions. However for public key cryptography the results are much less clear. \end{abstract

Introduction to Mirror Theory: Analysis of Systems of Linear Equalities and Linear Non Equalities for Cryptography

\begin{abstract} In this paper we will first study two closely related problems:\\ 1. The problem of distinguishing $f(x\Vert 0)\oplus f(x \Vert 1)$ where $f$ is a random permutation on $n$ bits. This problem was first studied by Bellare and Implagliazzo in~\cite{BI}.\\ 2. The so-called ``Theorem $P_i \oplus P_j$\u27\u27 of Patarin (cf~\cite{P05}). Then, we will see many variants and generalizations of this ``Theorem $P_i \oplus P_j$\u27\u27 useful in Cryptography. In fact all these results can be seen as part of the theory that analyzes the number of solutions of systems of linear equalities and linear non equalities in finite groups. We have nicknamed these analysis ``Mirror Theory\u27\u27 due to the multiples induction properties that we have in it. \end{abstract

Mirror Theory and Cryptography

``Mirror Theory\u27\u27 is the theory that evaluates the number of solutions of affine systems of equalities (=) and non equalities ($\neq$) in finite groups. It is deeply related to the security and attacks of many generic cryptographic secret key schemes, for example random Feistel schemes (balanced or unbalanced), Misty schemes, Xor of two pseudo-random bijections to generate a pseudo-random function etc. In this paper we will assume that the groups are abelian. Most of time in cryptography the group is $((\mathbb{Z}/2\mathbb{Z})^n, \oplus)$ and we will concentrate this paper on these cases. We will present here general definitions, some theorems, and many examples and computer simulations

Security of balanced and unbalanced Feistel Schemes with Linear Non Equalities

\begin{abstract} In this paper we will study 2 security results ``above the birthday bound\u27\u27 related to secret key cryptographic problems.\\ 1. The classical problem of the security of 4, 5, 6 rounds balanced Random Feistel Schemes.\\ 2. The problem of the security of unbalanced Feistel Schemes with contracting functions from $2n$ bits to $n$ bits. This problem was studied by Naor and Reingold~\cite{NR99} and by~\cite{YPL} with a proof of security up to the birthday bound.\\ These two problems are included here in the same paper since their analysis is closely related, as we will see. In problem 1 we will obtain security result very near the information bound (in $O(\frac {2^n}{n})$) with improved proofs and stronger explicit security bounds than previously known. In problem 2 we will cross the birthday bound of Naor and Reingold. For some of our proofs we will use~\cite{A2} submitted to Crypto 2010. \end{abstract

CODA: visual studies now

The intention of this critical project is to foster a conversation that foregrounds, and builds from, the complexities of interdisciplinary collaboration, its strengths and weaknesses, contributions and gaps. Our aim is to provide an international forum for the development of visual research; provoke more acceptance, understanding and discussion of a wide range of methods, approaches, theories and paradigms that constitute image-based research; reduce the disparity in emphasis between visual and written studies in scholarly research; and bridge the gap between empirically grounded visually- based research across the spectrum of the social sciences, arts, and humanities