The characterization of hyper-bent function with multiple trace terms in the extension field

Bent functions are maximally nonlinear Boolean functions with an even number of variables, which include a subclass of functions, the so-called hyper-bent functions whose properties are stronger than bent functions and a complete classification of hyper-bent functions is elusive and inavailable.~In this paper,~we solve an open problem of Mesnager that describes hyper-bentness of hyper-bent functions with multiple trace terms via Dillon-like exponents with coefficients in the extension field~${\mathbb{F}}_{2^{2m}}$~of this field~${\mathbb{F}}_{2^m}$. By applying Möbius transformation and the theorems of hyperelliptic curves, hyper-bentness of these functions are successfully characterized in this field~${\mathbb{F}}_{2^{2m}}$ with~$m$~odd integer.