2025-09-23
11:00
Salle 2
Exponential sums and Linear cryptanalysis: Analysis of Butterfly-like constructions
This presentation focuses on the recently identified links between algebraic geometry and symmetric cryptography. Specifically, we demonstrate how bounds on exponential sums, based on results from Deligne, Denef–Loeser and Rojas–León, can be used to evaluate the correlations of linear approximations in cryptographic constructions with a low algebraic degree. This yields concrete bounds for Butterfly-like designs, such as the Flystel. These results reinforce security arguments against linear cryptanalysis, notably by resolving a conjecture on the Flystel construction.
