Two new families of bivariate APN functions

Abstract

In this work, we present two new families of quadratic APN functions. The first one (F1) is constructed via biprojective polynomials. This family includes one of the two APN families introduced by G\"olo\v{g}lu in 2022. Then, following a similar approach as in Li \emph{et al.} (2022), we give another family (F2) obtained by adding certain terms to F1. As a byproduct, this second family includes one of the two families introduced by Li \emph{et al.} (2022). Moreover, we show that for $n=12$, from our constructions, we can obtain APN functions that are CCZ-inequivalent to any other known APN function over $\mathbb{F}_{2^{12}}$.