718 results

• • Seminar

  • Cryptography

  Some new results on cube attacks against Trivium

  • December 14, 2018

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

  Speaker : Tian Tian - Université de Zhengzhou

  Trivium is a bit oriented synchronous stream cipher designed by Cannière and Preneel. It is one of the eSTREAM hardware-oriented finalists and an International Standard under ISO/IEC 29192-3:2012. Cube attacks are an important type of key recovery attack against Trivium. First, I will give a survey on cube attacks against Trivium. Second, I will present our recent results including an algebraic[…]

• • Seminar

  • Cryptography

  Cryptanalyse algébrique de DAGS

  • September 27, 2019

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

  Speaker : Magali Bardet - université de Rouen

  Elise Barelli et Alain Couvreur ont présenté une attaque dévastatrice sur le cryptosystème DAGS soumis au 1er tour de la compétition du NIST autour d'algorithmes de cryptographie post-quantiques. Je présenterai une explication précise de la résolution par bases de Gröbner de leur modélisation algébrique, expliquant l'efficacité de l'attaque pour les paramètres de DAGS publiés au NIST.<br/> lien:[…]

• • Seminar

  • Cryptography

  Grost Distinguishing Attack: A new rebound attack of an AES-like permutation

  • March 02, 2018

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

  Speaker : Victor Cauchois - DGA et IRMAR

  Grostl est une fonction de hachage finaliste de la compétition SHA-3. Elle est dotée d'une preuve de sécurité qui assure sa résistance aux attaques en collision, pré-image et seconde pré-image sous l'hypothèse que deux permutations internes sont idéales. Ces permutations, 14 tours d'un SPN, calques de l'AES, présentent une structure sensible aux attaques rebond. Ces attaques sont des attaques[…]

• • Seminar

  • Cryptography

  Discrete logarithm computation in finite fields GF(p^k) with NFS

  • March 01, 2019

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

  Speaker : Aurore Guillevic - INRIA

  Pairings on elliptic curves are involved in signatures, NIZK, and recently in blockchains (ZK-SNARKS).<br/> These pairings take as input two points on an elliptic curve E over a finite field, and output a value in an extension of that finite field. Usually for efficiency reasons, this extension degree is a power of 2 and 3 (such as 12,18,24), and moreover the characteristic of the finite field has[…]

• • Seminar

  • Cryptography

  Post-quantum cryptography based on supersingular isogeny problems?

  • October 25, 2019

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

  Speaker : Christophe Petit - University of Birmingham

  The security of many cryptographic protocols in use today relies on the computational hardness of mathematical problems such as integer factorization. These problems can be solved using quantum computers, and therefore most of our security infrastructures will become completely insecure once quantum computers are built. Post-quantum cryptography aims at developing security protocols that will[…]

• • Seminar

  • Cryptography

  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[…]