624 results

  • Extended Private Information Retrieval Protocols: definitions,

    • October 30, 2009

    • IRMAR - Université de Rennes - Campus Beaulieu Bat. 22, RDC, Rennes - Amphi Lebesgue

    Speaker : Julien Bringer - Sagem Sécurité

    Cet exposé est basé sur des travaux communs avec Hervé Chabanne, David Pointcheval, Qiang Tang menés dans le cadre du projet ANR RNRT BACH (Biometric Authentication with Cryptographic Handling).<br/> Extended Private Information Retrieval (EPIR) is a generalization of the notion of Private Information Retrieval (PIR). The principle is to enable a user to privately evaluate a fixed and public[…]
  • (Yet Another) Analysis of the Linux Random Number Generator

    • October 23, 2009

    • IRMAR - Université de Rennes - Campus Beaulieu Bat. 22, RDC, Rennes - Amphi Lebesgue

    Speaker : Andrea Roeck - INRIA Rocquencourt

    The Linux random number generator is part of the kernel since 1994. It collects entropy from user input, interrupts and disk movements and claims to output high quality random numbers. There are two different versions: /dev/random which blocks if the internal entropy count goes to zero and /dev/urandom which is faster since it produces as many bits as the user wants to. The only official[…]
  • Rebound Attack on the Full LANE Compression Function

    • October 23, 2009

    • IRMAR - Université de Rennes - Campus Beaulieu Bat. 22, RDC, Rennes - Amphi Lebesgue

    Speaker : Maria Naya - INRIA Rocquencourt

    In this work, we apply the rebound attack to the AES based SHA-3 candidate LANE. The hash function LANE uses a permutation based compression function, consisting of a linear message expansion and 6 parallel lanes. In the rebound attack on LANE, we apply several new techniques to construct a collision for the full compression function of LANE-256 and LANE-512. Using a relatively sparse truncated[…]
  • Key Recovery Attacks of Practical Complexity on AES Variants With Up To 10 Rounds

    • September 25, 2009

    • IRMAR - Université de Rennes - Campus Beaulieu Bat. 22, RDC, Rennes - Amphi Lebesgue

    Speaker : Orr Dunkelman - ENS

    AES is the best known and most widely used block cipher. Its three versions (AES-128, AES-192, and AES-256) differ in their key sizes (128 bits, 192 bits and 256 bits) and in their number of rounds (10, 12, and 14, respectively). In the case of AES-128, there is no known attack which is faster than the 2^{128} complexity of exhaustive search. However, AES-192 and AES-256 were recently shown to be[…]
  • Une variante elliptique du test de primalité AKS

    • June 26, 2009

    • IRMAR - Université de Rennes - Campus Beaulieu Bat. 22, RDC, Rennes - Amphi Lebesgue

    Speaker : Reynald Lercier - CELAR/IRMAR

    Nous présenterons dans cet exposé le test AKS et ses améliorations, qui permettent de prouver qu'un entier N est un nombre premier. Nous verrons comment il nous a été récemment possible d'obtenir une variante de ces tests plus efficace, en généralisant aux courbes elliptiques, des idées de Berrizbeitia - Cheng - Avanzi - Mihailescu - Bernstein. En particulier, il nous est possible de nous[…]
  • Familles de courbes définies sur tout corps fini ayant un nombre de classes

    • June 19, 2009

    • IRMAR - Université de Rennes - Campus Beaulieu Bat. 22, RDC, Rennes - Amphi Lebesgue

    Speaker : Stéphane Ballet - IML

    Nous étudions la notion de suites asymptotiquement exactes de corps de fonctions algébriques introduite par Tsfasman en 1991. Plus précisément, nous construisons explicitement des suites asymptotiquement exactes de corps de fonctions algébriques définis sur des corps finis quelconques, en particulier quand q n'est pas un carré. Ensuite, nous prouvons que ces suites constituent des familles[…]