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• • Séminaire

  • Cryptographie

  New Representations of the AES Key Schedule

  • 10 juin 2022

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

  Orateur : Clara Pernot - INRIA Paris

  In this talk we present a new representation of the AES key schedule, with some implications to the security of AES-based schemes. In particular, we show that the AES-128 key schedule can be split into four independent parallel computations operating on 32 bits chunks, up to linear transformation. Surprisingly, this property has not been described in the literature after more than 20 years of[…]

• • Séminaire

  • Cryptographie

  Fault tolerant algorithms via decoding: Interleaving techniques

  • 17 juin 2022

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

  Orateur : Eleonora Guerrini - Université Montpellier

  Evaluation Interpolation algorithms are a key tool for the algebraic decoding of a large class of codes, including the famous Reed Solomon codes. Recent techniques allow the use of this type of decoding in the more general setting of fault tolerant algorithms, where one has to interpolate erroneous data (potentially computed by an untrusted entity). In this talk we will present algorithms to[…]

• • Séminaire

  • Cryptographie

  Soutenance de thèse: Algebraic Cryptanalysis of the Shortest Vector Problem in Ideal Lattices

  • 13 juin 2022

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

  Orateur : Olivier Bernard - Rennes

• • Séminaire

  • Cryptographie

  Isogenies over Hessian Model of Elliptic Curves

  • 03 juin 2022

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

  Orateur : Emmanuel Fouotsa - Université de Bamenda

  In this talk we present explicit formulas for isogenies between elliptic curves in (twisted) Hessian form. We examine the numbers of operations in the base field to compute the formulas. In comparison with other isogeny formulas, we note that the obtained formulas for twisted Hessian curves have the lowest costs for processing the kernel and the X-affine formula has the lowest cost for processing[…]

• • Séminaire

  • Cryptographie

  Cryptographie post-quantique fondée sur les codes : les candidats à la standardisation

  • 25 mars 2020

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

  Orateur : Nicolas Sendrier - INRIA

  Au second tour du processus de standardisation du NIST, il reste 7 candidats dont la sécurité est fondée sur les code correcteurs, tous sont des mécanismes d'échange de clé. Nous les classifierons selon leurs hypothèses de sécurité et leurs propriétés. Nous trouvons les systèmes « historiques » (Classic McEliece et NTS-KEM), les systèmes fondés sur des matrices creuses et quasi-cycliques (BIKE,[…]

• • Séminaire

  • Cryptographie

  PARASITE: PAssword Recovery Attack against Srp Implementations in ThE wild

  • 03 décembre 2021

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

  Orateur : Daniel De Almeida Braga - Université Rennes 1

  Protocols for password-based authenticated key exchange (PAKE) allow two users sharing only a short, low-entropy password to establish a secure session with a cryptographically strong key. The challenge in designing such protocols is that they must resist offline dictionary attacks in which an attacker exhaustively enumerates the dictionary of likely passwords in an attempt to match the used[…]