Package org.bouncycastle.pqc.legacy.crypto.rainbow.util

Class ComputeInField

java.lang.Object
org.bouncycastle.pqc.legacy.crypto.rainbow.util.ComputeInField
public class ComputeInField extends Object
This class offers different operations on matrices in field GF2^8.

Implemented are functions: - finding inverse of a matrix - solving linear equation systems using the Gauss-Elimination method - basic operations like matrix multiplication, addition and so on.

  • Constructor Summary

    Constructors
    Constructor
    Description
    ComputeInField()
    Constructor with no parameters

  • Method Summary

    Modifier and Type
    Method
    Description
    short[][]
    addSquareMatrix(short[][] matrix1, short[][] matrix2)
    Adds the n x n matrices matrix1 and matrix2
    short[]
    addVect(short[] vector1, short[] vector2)
    Addition of two vectors
    short[][]
    inverse(short[][] coef)
    This function computes the inverse of a given matrix using the Gauss- Elimination method.
    short[]
    multiplyMatrix(short[][] M1, short[] m)
    This function multiplies a given matrix with a one-dimensional array.
    short[][]
    multiplyMatrix(short[][] M1, short[][] M2)
    This function multiplies two given matrices.
    short[][]
    multMatrix(short scalar, short[][] matrix)
    Multiplies matrix with scalar
    short[]
    multVect(short scalar, short[] vector)
    Multiplies vector with scalar
    short[][]
    multVects(short[] vector1, short[] vector2)
    Multiplication of column vector with row vector
    short[]
    solveEquation(short[][] B, short[] b)
    This function finds a solution of the equation Bx = b.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • ComputeInField

      public ComputeInField()
      Constructor with no parameters

  • Method Details

    • solveEquation

      public short[] solveEquation(short[][] B, short[] b)
      This function finds a solution of the equation Bx = b. Exception is thrown if the linear equation system has no solution
      Parameters:
      B - this matrix is the left part of the equation (B in the equation above)
      b - the right part of the equation (b in the equation above)
      Returns:
      x the solution of the equation if it is solvable null otherwise
      Throws:
      RuntimeException - if LES is not solvable

    • inverse

      public short[][] inverse(short[][] coef)
      This function computes the inverse of a given matrix using the Gauss- Elimination method.

      An exception is thrown if the matrix has no inverse

      Parameters:
      coef - the matrix which inverse matrix is needed
      Returns:
      inverse matrix of the input matrix. If the matrix is singular, null is returned.
      Throws:
      RuntimeException - if the given matrix is not invertible

    • multiplyMatrix

      public short[][] multiplyMatrix(short[][] M1, short[][] M2) throws RuntimeException
      This function multiplies two given matrices. If the given matrices cannot be multiplied due to different sizes, an exception is thrown.
      Parameters:
      M1 - -the 1st matrix
      M2 - -the 2nd matrix
      Returns:
      A = M1*M2
      Throws:
      RuntimeException - in case the given matrices cannot be multiplied due to different dimensions.

    • multiplyMatrix

      public short[] multiplyMatrix(short[][] M1, short[] m) throws RuntimeException
      This function multiplies a given matrix with a one-dimensional array.

      An exception is thrown, if the number of columns in the matrix and the number of rows in the one-dim. array differ.

      Parameters:
      M1 - the matrix to be multiplied
      m - the one-dimensional array to be multiplied
      Returns:
      M1*m
      Throws:
      RuntimeException - in case of dimension inconsistency

    • addVect

      public short[] addVect(short[] vector1, short[] vector2)
      Addition of two vectors
      Parameters:
      vector1 - first summand, always of dim n
      vector2 - second summand, always of dim n
      Returns:
      addition of vector1 and vector2
      Throws:
      RuntimeException - in case the addition is impossible due to inconsistency in the dimensions

    • multVects

      public short[][] multVects(short[] vector1, short[] vector2)
      Multiplication of column vector with row vector
      Parameters:
      vector1 - column vector, always n x 1
      vector2 - row vector, always 1 x n
      Returns:
      resulting n x n matrix of multiplication
      Throws:
      RuntimeException - in case the multiplication is impossible due to inconsistency in the dimensions

    • multVect

      public short[] multVect(short scalar, short[] vector)
      Multiplies vector with scalar
      Parameters:
      scalar - galois element to multiply vector with
      vector - vector to be multiplied
      Returns:
      vector multiplied with scalar

    • multMatrix

      public short[][] multMatrix(short scalar, short[][] matrix)
      Multiplies matrix with scalar
      Parameters:
      scalar - galois element to multiply matrix with
      matrix - 2-dim n x n matrix to be multiplied
      Returns:
      matrix multiplied with scalar

    • addSquareMatrix

      public short[][] addSquareMatrix(short[][] matrix1, short[][] matrix2)
      Adds the n x n matrices matrix1 and matrix2
      Parameters:
      matrix1 - first summand
      matrix2 - second summand
      Returns:
      addition of matrix1 and matrix2; both having the dimensions n x n
      Throws:
      RuntimeException - in case the addition is not possible because of different dimensions of the matrices