walshTransform {boolfun}R Documentation

Fast Walsh Hadamard Transform

Description

walshTransform returns the Walsh-Hadamard transform of the input truth table.

Usage

walshTransform( truthTable )

Arguments

truthTable a vector of integers containing 2^n binary entries - see BooleanFunction.

Details

The value is computed in O(n2^n) using C code according to the Fast Walsh Transform algorithm. For more information, type vignette(boolfun).

Value

walshTransform returns a vector of integers having the same length as the input vector. The i^th entry can be seen as a "similarity" or "association" with the linear function determined by the integer i (i.e. there are 2^n such functions).

References

James L. Massey. The Discrete Fourier Transform in Coding and Cryptography. IEEE Inform. Theory Workshop, ITW 1998, pages 9–11.

Ann Braeken. Cryptographic Properties of Boolean Functions and S-Boxes. phd thesis - 2006.

The vignette of this package.

See Also

BooleanFunction

Examples

tt <- c(0,1,1,0,1,0,0,1)
wh <- walshTransform(tt)

[Package boolfun version 0.2.6 Index]