Bent and bent(4) spectra of Boolean functions over finite fields

Nurdagül Anbar Meidl, Wilfried Meidl

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

For c is an element of F(2)n, a c-bent4 function f from the finite field F(2)n to F-2 is a function with a fiat spectrum with respect to the unitary transform V-f(c), which is designed to describe the component functions of modified planar functions. For c = 0 the transform V-f(c) reduces to the conventional Walsh transform, and hence a 0-bent4 function is bent. In this article we generalize the concept of partially bent functions to the transforms V-f(c). We show that every quadratic function is partially bent, and hence it is plateaued with respect to any of the transforms V-f(c). In detail we analyse two quadratic monomials. The first has values as small as possible in its spectra with respect to all transforms V-f(c), and the second has a flat spectrum for a large number of c. Moreover, we show that every quadratic function is c-bent4 for at least three distinct c. In the last part we analyse a cubic monomial. We show that it is c-bent(4) only for c = 1, the function is then called negabent, which shows that non-quadratic functions exhibit a different behaviour. (C) 2017 Elsevier Inc. All rights reserved.
Original languageEnglish
JournalFinite Fields and Their Applications
Volume46
Pages (from-to)163-178
ISSN1071-5797
DOIs
Publication statusPublished - 2017

Keywords

  • Bent function
  • Negabent function
  • Bent4
  • Boolean function
  • Walsh transform
  • Quadratic functions

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