Almost Perfect Nonlinear functions

Thierry Pierre Berger (1) , Anne Canteaut (2) , Pascale Charpin (2) , Yann Laigle-Chapuy (2)

1 LACO - Laboratoire d'Arithmétique, de Calcul formel et d'Optimisation
2 CODES - Coding and cryptography

We investigate some open problems on Almost Perfect Nonlinear (APN) functions over a finite field of characteristic $2$. We provide new characterizations of APN functions and of APN permutations by means of their component functions. We generalize some results of Nyberg (1994) and strengthen a conjecture on the upper bound of nonlinearity of APN functions. We also focus on the case of quadratic functions. We contribute to the current works on APN quadratic functions, by proving that a large class of quadratic functions cannot be APN.

Mots clés: BOOLEAN FUNCTION; ALMOST BENT FUNCTION; ALMOST PERFECT NONLINEAR FUNCTION; POWER FUNCTION; PERMUTATION POLYNOMIAL

Domaines: Autre [cs.OH]

Thierry Pierre Berger, Anne Canteaut, Pascale Charpin, Yann Laigle-Chapuy. Almost Perfect Nonlinear functions. [Research Report] RR-5774, INRIA. 2005, pp.28. ⟨inria-00070246⟩