HFE
Class Transform4

java.lang.Object
  |
  +--HFE.Transform4

class Transform4

extends java.lang.Object

Transform4 provides a affine transformation (i.e. S,T in terms of HFE), i.e. computes y = M*x + m where M and m are the affine transformation and x/y are input/output. All elements in the underlaying matrix and vector are taken from Field4.

Version:

0.1

Field Summary

private LUDecomposition4	lu holds the LU decomposition of matrix M for the reverse affine transformation.
private int[]	m holds the vector m for the affine transformation.
private Matrix4	M holds the bijective matrix M for the affine transformation.
private static int	rowCol the number of rows and columns, which is taken from the field extension.

Constructor Summary

Transform4()
Generates a affine transformation which is the identity, i.e.

Transform4(java.util.Random rnd)
Generates a affine transformation using a PRNG

Method Summary

Poly4MultiLinear[]	getTransform() returns the transformation in terms of polynomials
static void	main(java.lang.String[] args) Calls the testIt() method
static void	testIt() Tests the functionality of the class.
void	transform(int[] vec, int[] res) applies the transformation to a given vector, i.e.
Poly4MultiSquare[]	transform(Poly4MultiSquare[] in) Applies the transformation to a given vector of polynomials, i.e.
(package private) void	untransform(int[] vec, int[] res) reverts the transformation to a given vector, i.e.
void	writeString() Writes the current transformation to stdout

Methods inherited from class java.lang.Object

, clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait

Field Detail

M

private Matrix4 M

holds the bijective matrix M for the affine transformation.

lu

private LUDecomposition4 lu

holds the LU decomposition of matrix M for the reverse affine transformation.

m

private int[] m

holds the vector m for the affine transformation.

rowCol

private static int rowCol

the number of rows and columns, which is taken from the field extension.

Constructor Detail

Transform4

public Transform4()

Generates a affine transformation which is the identity, i.e. M = I and m = 0.

Transform4

public Transform4(java.util.Random rnd)

Generates a affine transformation using a PRNG

Parameters:

rnd - Random number generator for generating the transformation

Method Detail

transform

public void transform(int[] vec,
                      int[] res)

applies the transformation to a given vector, i.e. res = M*v^T + m

Parameters:

vec - vector which should be transformed using this

res - vector under this transformation

transform

public Poly4MultiSquare[] transform(Poly4MultiSquare[] in)

Applies the transformation to a given vector of polynomials, i.e. res = M*in + m.

Parameters:

in - vector which should be transformed using this

Returns:

A vector of polynomials

untransform

void untransform(int[] vec,
                 int[] res)

reverts the transformation to a given vector, i.e. computes res in vec = M*res^T + m

Parameters:

vec - vector which should be untransformed using this - is changed in this method

res - vector under this transformation

getTransform

public Poly4MultiLinear[] getTransform()

returns the transformation in terms of polynomials

writeString

public void writeString()

Writes the current transformation to stdout

testIt

public static void testIt()

Tests the functionality of the class. Is called by the main method.

main

public static void main(java.lang.String[] args)

Calls the testIt() method