Two infinite classes of rotation symmetric bent functions with simple representation

Abstract: In the literature, few $n$-variable rotation symmetric bent functions have been constructed. In this paper, we present two infinite classes of rotation symmetric bent functions on $\mathbb{F}<em>2<sup>{n}$ of the two forms: {\rm (i)} $$f(x)=\sum</em>{i=0}^{{m-1}x_ix_{i+m}} + \gamma(x_0+x_m,\cdots, x_{m-1}+x_{2m-1})$$, {\rm (ii)} $$f_t(x)= \sum_{i=0}^{{n-1}(x_ix_{i+t}x_{i+m}} +x_{i}x_{i+t})+ \sum_{i=0}^{{m-1}x_ix_{i+m}+} \gamma(x_0+x_m,\cdots, x_{m-1}+x_{2m-1})$$, \noindent where $n=2m$, $\gamma(X_0,X_1,\cdots, X_{m-1})$ is any rotation symmetric polynomial, and $m/gcd(m,t)$ is odd. The class (i) of rotation symmetric bent functions has algebraic degree ranging from 2 to $m$ and the other class (ii) has algebraic degree ranging from 3 to $m$.