org.spongycastle.pqc.math.linearalgebra

Class GF2mMatrix

java.lang.Object

org.spongycastle.pqc.math.linearalgebra.Matrix

org.spongycastle.pqc.math.linearalgebra.GF2mMatrix

public class GF2mMatrix
extends Matrix

This class describes some operations with matrices over finite field GF(2^m) with small m (1< m <32).

See Also:

Matrix

Field Summary

Fields

Modifier and Type	Field and Description
protected GF2mField	field finite field GF(2^m)
protected int[][]	matrix For the matrix representation the array of type int[][] is used, thus every element of the array keeps one element of the matrix (element from finite field GF(2^m))

Fields inherited from class org.spongycastle.pqc.math.linearalgebra.Matrix

MATRIX_TYPE_RANDOM_LT, MATRIX_TYPE_RANDOM_REGULAR, MATRIX_TYPE_RANDOM_UT, MATRIX_TYPE_UNIT, MATRIX_TYPE_ZERO, numColumns, numRows

Constructor Summary

Constructors

Modifier	Constructor and Description
	GF2mMatrix(GF2mField field, byte[] enc) Constructor.
protected	GF2mMatrix(GF2mField field, int[][] matrix) Constructor.
	GF2mMatrix(GF2mMatrix other) Copy constructor.

Method Summary

Modifier and Type	Method and Description
Matrix	computeInverse() Compute the inverse of this matrix.
boolean	equals(java.lang.Object other) Checks if given object is equal to this matrix.
byte[]	getEncoded()
int	hashCode()
boolean	isZero() Check if this is the zero matrix (i.e., all entries are zero).
Vector	leftMultiply(Vector vector) Compute the product of a vector and this matrix.
Matrix	rightMultiply(Matrix a) Compute the product of this matrix and another matrix.
Matrix	rightMultiply(Permutation perm) Compute the product of this matrix and a permutation.
Vector	rightMultiply(Vector vector) Compute the product of this matrix and a vector.
java.lang.String	toString()

Methods inherited from class org.spongycastle.pqc.math.linearalgebra.Matrix

getNumColumns, getNumRows

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

field

protected GF2mField field

finite field GF(2^m)

matrix

protected int[][] matrix

For the matrix representation the array of type int[][] is used, thus every element of the array keeps one element of the matrix (element from finite field GF(2^m))

Constructor Detail

GF2mMatrix

public GF2mMatrix(GF2mField field,
                  byte[] enc)

Constructor.

Parameters:

field - a finite field GF(2^m)

enc - byte[] matrix in byte array form

GF2mMatrix

public GF2mMatrix(GF2mMatrix other)

Copy constructor.

Parameters:

other - another GF2mMatrix

GF2mMatrix

protected GF2mMatrix(GF2mField field,
                     int[][] matrix)

Constructor.

Parameters:

field - a finite field GF(2^m)

matrix - the matrix as int array. Only the reference is copied.

Method Detail

getEncoded

public byte[] getEncoded()

Specified by:

getEncoded in class Matrix

Returns:

a byte array encoding of this matrix

isZero

public boolean isZero()

Check if this is the zero matrix (i.e., all entries are zero).

Specified by:

isZero in class Matrix

Returns:

true if this is the zero matrix

computeInverse

public Matrix computeInverse()

Compute the inverse of this matrix.

Specified by:

computeInverse in class Matrix

Returns:

the inverse of this matrix (newly created).

rightMultiply

public Matrix rightMultiply(Matrix a)

Description copied from class: Matrix

Compute the product of this matrix and another matrix.

Specified by:

rightMultiply in class Matrix

Parameters:

a - the other matrix

Returns:

this * a (newly created)

rightMultiply

public Matrix rightMultiply(Permutation perm)

Description copied from class: Matrix

Compute the product of this matrix and a permutation.

Specified by:

rightMultiply in class Matrix

Parameters:

perm - the permutation

Returns:

this * p (newly created)

leftMultiply

public Vector leftMultiply(Vector vector)

Description copied from class: Matrix

Compute the product of a vector and this matrix. If the length of the vector is greater than the number of rows of this matrix, the matrix is multiplied by each m-bit part of the vector.

Specified by:

leftMultiply in class Matrix

Parameters:

vector - a vector

Returns:

vector * this (newly created)

rightMultiply

public Vector rightMultiply(Vector vector)

Description copied from class: Matrix

Compute the product of this matrix and a vector.

Specified by:

rightMultiply in class Matrix

Parameters:

vector - a vector

Returns:

this * vector (newly created)

equals

public boolean equals(java.lang.Object other)

Checks if given object is equal to this matrix. The method returns false whenever the given object is not a matrix over GF(2^m).

Overrides:

equals in class java.lang.Object

Parameters:

other - object

Returns:

true or false

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Specified by:

toString in class Matrix

Returns:

a human readable form of the matrix.