599 results

  • A Modular Security Analysis of EAP and IEEE 802.11

    • April 07, 2017

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

    Speaker : Haakon Jacobsen - TBD

    The Extensible Authentication Protocol (EAP) is a widely used three-party authentication framework that allows a client to connect to a wireless access point it does not share a secret with, using a mutually trusted server. EAP is often found in enterprise networks or large organizations to provide central key-management and user authentication; one prime example being the eduroam network.<br/[…]
  • Attaques sur des conversions IND-CCA de systèmes basés sur les codes

    • March 24, 2017

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

    Speaker : Paul Stankovski - Université de Lund

    Algorithms for secure encryption in a post-quantum world are currently receiving a lot of attention in the research community, including several larger projects and a standardization effort from {NIST}. One of the most promising algorithms is the code-based scheme called QC-MDPC, which has excellent performance and a small public key size.<br/> In this work we present a very efficient key[…]
  • Improving greedy nonrandomness detectors for stream ciphers

    • March 24, 2017

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

    Speaker : Paul Stankovski - Université de Lund

    We consider the problem of designing distinguishers and nonrandomness detectors for stream ciphers using the maximum degree monomial test. We construct an improved algorithm to determine the subset of key and IV-bits used in the test. The algorithm is generic, and can be applied to any stream cipher. In addition to this, the algorithm is highly tweakable, and can be adapted depending on the[…]
  • Coercion-resistant Internet voting made practical

    • March 03, 2017

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

    Speaker : Jacques Traore - Orange Labs

    Internet voting offers a better voting experience since voters can cast their votes from their computers or even smartphones. By eliminating the need to visit polling places, it may attract more voters and thus increase voter turnout. However, it is still not widely spread owing to many inherent concerns such as risks entailed by the lack of private polling booths. Indeed, this may ease coercion[…]
  • Permutations complètes en caractéristique 2.

    • February 10, 2017

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

    Speaker : Valentin Suder - Université de Versailles Saint-Quentin

    Dans ce travail, nous nous intéressons aux permutations complètes, c’est-à-dire aux fonctions bijectives $x\mapsto f(x)$ telles que $x\mapsto f(x)+x$ soient aussi bijectives. Plus particulièrement, nous nous intéressons aux permutations complètes sur les corps finis $\mathbb{F}_{2^n}$. En caractéristique 2, la définition des permutations complètes coincide avec celle des orthomorphismes. Nous[…]
  • Improved Cryptanalysis of Rank Metric Schemes Based on Gabidulin Codes.

    • February 03, 2017

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

    Speaker : Hervé Talé Kalachi - Université de Rouen et Université de Yaoundé, Cameroun

    In this presentation, we prove that any variant of the GPT cryptosystem which uses a right column scrambler over the extension field as advocated by the works of Gabidulin et al. with the goal to resist to Overbeck’s structural attack are actually still vulnerable to that attack. We show that by applying the Frobenius operator appropriately on the public key, it is possible to build a Gabidulin[…]