A Note on “Differential Properties of $x \mapsto x^{2^{t}-1}$”

Blondeau and colleagues recently conjectured a characterization of when x^2t-1 is an almost perfect nonlinear function on F₂n. In this paper, we will prove the conjecture when n is even. The short proof uses a theorem of Hou and colleagues concerning reversed Dickson polynomials and a theorem of Payne.