599 results

  • Chiffrement (complètement) homomorphe : de la théorie à la pratique

    • June 20, 2014

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

    Speaker : Tancrède Lepoint - CryptoExperts

    Le chiffrement complètement homomorphe (parfois considéré comme le Saint Graal de la cryptographie) permet d'effectuer (de façon publique) des calculs arbitraires sur des messages chiffrés. Les premières instanciations de cette surprenante primitive ne peuvent être considérées comme pratiques, chaque multiplication de deux bits chiffrés nécessitant d'être suivie par une procédure de[…]
  • How to find low-weight polynomial multiples.

    • June 13, 2014

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

    Speaker : Carl Löndahl - Université de Lund

    We present an improved algorithm for finding low-weight multiples of polynomials over the binary field using coding heoretic methods. The associated code defined by the given olynomial has a cyclic structure, allowing an algorithm to earch for shifts of the sought minimum-weight odeword. Therefore, a code with higher dimension is onstructed, having a larger number of low-weight codewords nd[…]
  • Crypto coding

    • June 06, 2014

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

    Speaker : Jean-Philippe Aumasson - Kudelski Security

    La cryptographie est difficile à implémenter correctement; nous en avons récemment eu l'exemple avec "Heartbleed" et "goto fail". Nous essaierons d'abord de comprendre la source de ces problèmes, notamment en discutant les qualités de la librairie OpenSSL. Enfin, nous donnerons quelques exemples de recommendations aux développeurs pour éviter des problèmes propres à[…]
  • Decoding interleaved Gabidulin codes and skew complexity of sequences.

    • May 23, 2014

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

    Speaker : Vladimir Sidorenko - Univ. Ulm

    Gabidulin codes are the rank metric analogues of Reed?Solomon codes and have found many applications including network coding and cryptography. Interleaving or the direct sum of Gabidulin codes allows both decreasing the redundancy and increasing the error correcting capability for network coding. We consider a transform domain algorithm correcting both errors and erasures with interleaved[…]
  • Same-Values Analysis on Elliptic Curve Cryptography

    • April 25, 2014

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

    Speaker : Cédric Murdica - Secure-IC

    Elliptic Curve Cryptography (ECC) is believed to be unbreakable in the black box model, where the cryptanalyst has access to inputs and outputs only. However, it is not enough if the cryptosystem is embedded on a device that is physically accessible to potential attackers. In addition to inputs and outputs, the attacker can study the physical behaviour of the device such as the execution time or[…]
  • Beyond the black and grey box

    • April 25, 2014

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

    Speaker : Yoni De Mulder - University of Leuven

    In the white-box attack context, i.e., the setting where an implementation of a cryptographic algorithm is executed on an untrusted open platform, the adversary has full access to the implementation and its execution environment. As a result, the adversary is much more powerful than in a traditional black-box environment in which the adversary has only access to the inputs and outputs of a[…]