Current

The seminar is held on Tuesdays from 11 to 12 and is organised by Sabrina Kunzweiler and Maxime Bombar. Unless stated otherwise it takes place in room 2 of IMB. To get announcements, you can subscribe to the mailing list of the Bordeaux number theory seminars. Last minute changes may appear first on the IMB website.

• 2025-04-15
  11:00
  Salle 2
  Axel Lemoine (INRIA Paris)
  The Tangent Space Attack
  We propose a new method for retrieving the algebraic structure of a generic alternant code given any generator matrix, provided certain conditions are met. The central object of our work is the quadratic hull of the code, defined as the intersection of all quadrics passing through the columns of a given generator or parity-check matrix, where the columns are considered as points in affine or projective space. The geometric properties of this object reveal important information about the internal algebraic structure of the code. In the case of a Generalized Reed-Solomon code with a rate strictly less than 1/2, the quadratic hull is equivalent to a rational normal curve. By utilizing the concept of Weil restriction of affine varieties, we demonstrate that the quadratic hull of a generic dual alternant code inherits many interesting properties from the rational normal curve. If the rate of the generic alternant code is sufficiently high, this allows us to construct a polynomial-time algorithm for retrieving the underlying Generalized Reed-Solomon code, which leads to an efficient key-recovery attack against the McEliece cryptosystem when instantiated with this class of codes.
• 2025-04-22
  11:00
  Salle 2
  Camille Garnier (Université de Limoges)
  TBA
• 2025-05-13
  11:00
  Salle 2
  Wessel van Woerden (CANARI)
  TBA
• 2025-05-20
  11:00
  Salle 2
  Ludo Pulles (CWI Amsterdam)
  TBA
• 2025-05-27
  11:00
  Salle 2
  Jonathan Komada Eriksen (KU Leuven)
  TBA