511 results

  • An Algebraic Framework for Pseudorandom Functions and Applications to Related-Key Security

    • June 26, 2015

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

    Speaker : Alain Passelègue - ENS

    Pseudorandom functions (PRFs) are one of the most fundamental primitives in cryptography. In this work, we provide a new algebraic framework which encompasses many of the existing algebraic PRFs, including the ones by Naor and Reingold (FOCS'97), by Lewko and Waters (CCS'09), and by Boneh, Montgomery, and Raghunathan (CCS'10), as well as the related-key-secure PRFs by Bellare and[…]
  • Systèmes de chiffrement par bloc minimalistes, obfuscation et implémentations en "boite blanche"

    • June 19, 2015

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

    Speaker : Charles Bouillaguet - Université de Lille 1

    La plupart du temps, la sécurité des systèmes de chiffrement est évaluée en supposant que les adversaires interagissent avec le dispositif à travers une "interface", mais qu'ils n'ont pas le système de chiffrement sous la main pour étudier les détails de son fonctionnement interne. En effet, le fonctionnement de tels systèmes repose largement sur le fait qu'ils contiennent[…]
  • Gröbner Bases Techniques in Post-Quantum Cryptography

    • June 12, 2015

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

    Speaker : Ludovic Perret - LIP6

    After the publication of Shor's algorithm, it became evident the most popular public-key cryptographic systems that rely on the integer factorization problem or on the discrete logarithm problem would be easily solvable using large enough quantum computers (if such quantum computers are ever built). That triggered a vivid interest in the research of cryptographic algorithms (mostly public-key[…]
  • New multilinear maps over the integers

    • June 05, 2015

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

    Speaker : Jean-Sébastien Coron - Université du Luxembourg

    In the last few years, cryptographic multilinear maps have proved their tremendous potential as building blocks for new constructions, in particular the first viable approach to general program obfuscation. After the first candidate construction by Garg, Gentry and Halevi (GGH) based on ideal lattices, a second construction over the integers was described by Coron, Lepoint and Tibouchi (CLT).[…]
  • Disjunctions for Hash Proof Systems: New Constructions and Applications

    • April 24, 2015

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

    Speaker : Fabrice Ben Hamouda - ENS

    Hash Proof Systems were first introduced by Cramer and Shoup (Eurocrypt'02) as a tool to construct efficient chosen-ciphertext-secure encryption schemes. Since then, they have found many other applications, including password authenticated key exchange, oblivious transfer, and zero-knowledge arguments. One of the aspects that makes hash proof systems so interesting and powerful is that they[…]
  • Broadcast encryption: combinatorial vs. algebraic methods

    • April 10, 2015

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

    Speaker : Duong-Hieu Phan - ENS

    We consider a generalisation of the encryption from "one-to-one'' to "one-to-many'' communication, i.e. broadcast encryption. The objective is to allow a center to send secret messages to a large number of receivers. The security notion in “one-to-many” communications needs to be extended beyond the notion of confidentiality in “one-to-one” encryption in order to meet[…]