It is well known that the perfect nonlinearity of a function between finite groups G $G$ and H $H$ can be characterized by its graph in terms of relative difference set in the direct product GxH $G\times H$ (cf. [4])....
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It is well known that the perfect nonlinearity of a function between finite groups G $G$ and H $H$ can be characterized by its graph in terms of relative difference set in the direct product GxH $G\times H$ (cf. [4]). Let T $T$ be the infinite set of complex roots of unity. A T $T$-valued function f $f$ on an arbitrary finite group G $G$ is associated with a finite cyclic subgroup Tf ${T}_{f}$ in the multiplicative group of nonzero complex numbers. For a bent function f $f$ on G $G$ in general, its graph is not a relative difference set in the direct product GxTf $G\times {T}_{f}$. In this paper, we investigate the necessary and sufficient conditions under which the graph of a bent function f $f$ on G $G$ is a relative difference set in GxTf $G\times {T}_{f}$. Cyclotomic fields and their integral bases play an important role in our discussions.
It is important to study the new construction methods of bent functions. In this paper, we first propose a secondary construction method of (k + s)-variable bent function g through a family of s-plateaued functions f0...
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It is important to study the new construction methods of bent functions. In this paper, we first propose a secondary construction method of (k + s)-variable bent function g through a family of s-plateaued functions f0, f1,..., f2s- 1 on k variables with disjointWalsh supports, which can be obtained through any given (k - s)-variable bent function f by selecting 2s disjoint affine subspaces S0, S1,..., S2s- 1 of Fk 2 with dimension k - s to specify the Walsh support of these s-plateaued functions respectively, where s is a positive integer and k - s is a positive even integer. The dual functions of these newly constructed bent functions are determined. This secondary construction method of bent functions has a great improvement in counting. As a generalization, we find that the one initial (k - s)-variable bent function f can be replaced by several different (k - s)-variable bent functions. Compared to the first construction method, the latter one gives much more bent functions. It is worth mentioning that it can give all the 896 bent functions on 4 variables.
In this paper we study those bent functions which are linear on elements of spreads, their connections with ovals and line ovals, and we give descriptions of their dual bent functions. In particular, we give a geometr...
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In this paper we study those bent functions which are linear on elements of spreads, their connections with ovals and line ovals, and we give descriptions of their dual bent functions. In particular, we give a geometric characterization of Niho bent functions and of their duals, we give explicit formula for the dual bent function and present direct connections with ovals and line ovals. We also show that bent functions which are linear on elements of inequivalent spreads can be EA equivalent. (C) 2017 Elsevier Inc. All rights reserved.
bent functions are maximally nonlinear Boolean functions. Introduced by Rothaus and first examined by Dillon, these important functions have subsequently been studied by many researchers over the last four decades. Si...
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bent functions are maximally nonlinear Boolean functions. Introduced by Rothaus and first examined by Dillon, these important functions have subsequently been studied by many researchers over the last four decades. Since a complete classification of bent functions appears elusive, many researchers concentrate on methods for constructing bent functions. In this paper, we investigate constructions of bent functions from involutions over finite fields in even characteristic. We present a generic construction technique, study its equivalence issues and show that linear involutions (which are an important class of permutations) over finite fields give rise to bent functions in bivariate representations. In particular, we exhibit new constructions of bent functions involving binomial linear involutions, whose dual functions are directly obtained without computation. The existence of bent functions from involutions relies heavily on solving systems of equations over finite fields.
In this note, a new primary construction of bent functions consisting of a linear combination of 2(r) Niho exponents is presented. This construction generalizes one of the constructions proven by H. Dobbertin, G. Lean...
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In this note, a new primary construction of bent functions consisting of a linear combination of 2(r) Niho exponents is presented. This construction generalizes one of the constructions proven by H. Dobbertin, G. Leander, A. Canteaut, C. Carlet, P. Felke, and P. Gaborit.
In this paper, a technique for constructing p-ary bent functions from plateaued functions is presented. This generalizes earlier techniques of constructing bent from near-bent functions. The Fourier spectrum of quadra...
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In this paper, a technique for constructing p-ary bent functions from plateaued functions is presented. This generalizes earlier techniques of constructing bent from near-bent functions. The Fourier spectrum of quadratic monomials is analyzed, and examples of quadratic functions with highest possible absolute values in their Fourier spectrum are given. Applying the construction of bent functions to the latter class of functions yields bent functions attaining upper bounds for the algebraic degree when p = 3,5. Until now, no construction of bent functions attaining these bounds was known.
This work extends the idea introduced by Hou and Langevin (J. Combin. Theory, Ser. A, 80:232-246, 1997) of applying nonlinear permutations to (a portion of) the input variable space of a given Boolean function so that...
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This work extends the idea introduced by Hou and Langevin (J. Combin. Theory, Ser. A, 80:232-246, 1997) of applying nonlinear permutations to (a portion of) the input variable space of a given Boolean function so that the resulting function is bent. Applying such a permutation to a bent function that can be represented in a suitable form then gives an affine inequivalent bent function which potentially does not belong to the same class as the original one. While Hou and Langevin only provided two sporadic examples of bent functions that can be turned into affine inequivalent ones, in this article we identify two generic families of bent functions suitable for generating such affine inequivalent counterparts. The same method when applied to the Marioana-McFarland class of bent functions, depending on the subset of inputs to which a nonlinear action is applied, either lead to bent functions that are provably within the same class or to bent functions that are potentially outside this class. The problem of finding suitable permutations that act nonlinearly on more than two input variables of the initial function and ensure the bentness of the resulting function appears to be generally hard. In this direction, we only slightly extend the approach of Hou and Langevin by identifying suitable permutations that act nonlinearly on three input variabl es. Most notably, the existence of nonlinear permutations that act without strict separation of the input space in terms of linear and nonlinear action is also confirmed. Finally, we show a direct correspondence between (some classes of) bent functions and permutations by providing an efficient method to define permutations using the derivatives of a given bent function. This not only gives a relationship between two seemingly different algebraic objects, but also provides us with a new infinite family of permutations over finite fields.
bent functions are maximally nonlinear Boolean functions with an even number of variables. They have attracted a lot of research for four decades because of their own sake as interesting combinatorial objects, and als...
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bent functions are maximally nonlinear Boolean functions with an even number of variables. They have attracted a lot of research for four decades because of their own sake as interesting combinatorial objects, and also because of their relations to coding theory, sequences and their applications in cryptography and other domains such as design theory. In this paper we investigate explicit constructions of bent functions which are linear on elements of spreads. After presenting an overview on this topic, we study bent functions which are linear on elements of presemifield spreads and give explicit descriptions of such functions for known commutative presemifields. A direct connection between bent functions which are linear on elements of the Desarguesian spread and oval polynomials over finite fields was proved by Carlet and the second author. Very recently, further nice extensions have been made by Carlet in another context. We introduce oval polynomials for semifields which are dual to symplectic semifields. In particular, it is shown that from a linear oval polynomial for a semifield one can get an oval polynomial for transposed semifield.
We present a construction of partial spread bent functions using subspaces generated by linear recurring sequences (LRS). We first show that the kernels of the linear mappings defined by two LRS have a trivial interse...
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We present a construction of partial spread bent functions using subspaces generated by linear recurring sequences (LRS). We first show that the kernels of the linear mappings defined by two LRS have a trivial intersection if and only if their feedback polynomials are relatively prime. Then, we characterize the appropriate parameters for a family of pairwise coprime polynomials to generate a partial spread required for the support of a bent function, showing that such families exist if and only if the degrees of the underlying polynomials are either 1 or 2. We then count the resulting sets of polynomials and prove that, for degree 1, our LRS construction coincides with the Desarguesian partial spread. Finally, we perform a computer search of all PS- and PS+ bent functions of n = 8 variables generated by our construction and compute their 2-ranks. The results show that many of these functions defined by polynomials of degree d = 2 are not EA-equivalent to any Maiorana-McFarland or Desarguesian partial spread function.
For any Boolean function f on GF(2)(m), we define a sequence of ranks r(i)(f), 1 less than or equal to i less than or equal to m, which are invariant under the action of the general linear group GL(m, 2). If f is a cu...
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For any Boolean function f on GF(2)(m), we define a sequence of ranks r(i)(f), 1 less than or equal to i less than or equal to m, which are invariant under the action of the general linear group GL(m, 2). If f is a cubic bent function in 2k variables, we show that when r(3)(f) less than or equal to k, f is either obtained from a cubic bent function in 2k - 2 variables, or is in a well-known family of bent functions. We also determine all cubic bent functions in eight variables. (C) 1998 Elsevier Science B.V. All rights reserved.
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