Complete characterization of generalized bent and 2^k-bent Boolean functions

In this paper we investigate properties of generalized bent Boolean functions and 2k-bent (i.e., negabent, octabent, hex- adecabent, et al.) Boolean functions in a uniform framework. We generalize the work of Stˇ anicˇ a et al., present necessary and sufficient conditions for generalized bent Boolean functions and 2k-bent Boolean functions in terms of classical bent functions, and completely characterize these functions in a combinatorial form. The result of this paper further shows that all generalized bent Boolean functions are regular