Constructions of Bent Functions and Difference Sets

Based on the work of Rothaus [12], Olsen, Scholtz and Welch suggested the bent functions to be used as feed-forward functions to generate binary sequences which possess high linear complexity and very nearly optimum crosscorrelation properties [10]. In [7] Meier and Staffelbach discovered, that binary bent functions give a solution to the correlation problem when used as combining functions of several binary linear shiftregister sequences. One of their results is that bent functions are at maximum distance to the set of affine functions. We refer to [7] for the cryptographic background and motivation. The general theory of the bent functions from Z q n to Z q was developed by Kumar, Scholtz and Welch [2].