private static MaMaPe GetMMP(GF2Matrix H, IRandom SecRnd)
{
int n = H.ColumnCount;
GF2Matrix s = null;
Permutation p = new Permutation(n, SecRnd);
GF2Matrix hp = (GF2Matrix)H.RightMultiply(p);
GF2Matrix sInv = hp.LeftSubMatrix();
if ((s = InvertMatrix(sInv)) == null)
{
return(null);
}
GF2Matrix shp = (GF2Matrix)s.RightMultiply(hp);
GF2Matrix m = shp.RightSubMatrix();
return(new MaMaPe(sInv, m, p));
}
/// <summary>
/// Create an nxn random regular matrix
/// </summary>
///
/// <param name="N">Number of rows (and columns)</param>
/// <param name="SecRnd">Source of randomness</param>
private void AssignRandomRegularMatrix(int N, IRandom SecRnd)
{
RowCount = N;
ColumnCount = N;
_length = IntUtils.URShift((N + 31), 5);
_matrix = ArrayUtils.CreateJagged <int[][]>(RowCount, _length);
GF2Matrix lm = new GF2Matrix(N, Matrix.MATRIX_TYPE_RANDOM_LT, SecRnd);
GF2Matrix um = new GF2Matrix(N, Matrix.MATRIX_TYPE_RANDOM_UT, SecRnd);
GF2Matrix rm = (GF2Matrix)lm.RightMultiply(um);
Permutation perm = new Permutation(N, SecRnd);
int[] p = perm.GetVector();
for (int i = 0; i < N; i++)
{
Array.Copy(rm._matrix[i], 0, _matrix[p[i]], 0, _length);
}
}
/// <summary>
/// Create a nxn random regular matrix and its inverse
/// </summary>
///
/// <param name="N">Number of rows (and columns)</param>
/// <param name="SecRnd">Source of randomness</param>
/// <returns>The created random regular matrix and its inverse</returns>
public static GF2Matrix[] CreateRandomRegularMatrixAndItsInverse(int N, IRandom SecRnd)
{
GF2Matrix[] result = new GF2Matrix[2];
// First part: create regular matrix
int length = (N + 31) >> 5;
GF2Matrix lm = new GF2Matrix(N, Matrix.MATRIX_TYPE_RANDOM_LT, SecRnd);
GF2Matrix um = new GF2Matrix(N, Matrix.MATRIX_TYPE_RANDOM_UT, SecRnd);
GF2Matrix rm = (GF2Matrix)lm.RightMultiply(um);
Permutation p = new Permutation(N, SecRnd);
int[] pVec = p.GetVector();
int[][] matrix = ArrayUtils.CreateJagged <int[][]>(N, length);
for (int i = 0; i < N; i++)
{
Array.Copy(rm._matrix[pVec[i]], 0, matrix[i], 0, length);
}
result[0] = new GF2Matrix(N, matrix);
// Second part: create inverse matrix
// inverse to lm
GF2Matrix invLm = new GF2Matrix(N, Matrix.MATRIX_TYPE_UNIT);
for (int i = 0; i < N; i++)
{
int rest = i & 0x1f;
int q = IntUtils.URShift(i, 5);
int r = 1 << rest;
for (int j = i + 1; j < N; j++)
{
int b = (lm._matrix[j][q]) & r;
if (b != 0)
{
for (int k = 0; k <= q; k++)
{
invLm._matrix[j][k] ^= invLm._matrix[i][k];
}
}
}
}
// inverse to um
GF2Matrix invUm = new GF2Matrix(N, Matrix.MATRIX_TYPE_UNIT);
for (int i = N - 1; i >= 0; i--)
{
int rest = i & 0x1f;
int q = IntUtils.URShift(i, 5);
int r = 1 << rest;
for (int j = i - 1; j >= 0; j--)
{
int b = (um._matrix[j][q]) & r;
if (b != 0)
{
for (int k = q; k < length; k++)
{
invUm._matrix[j][k] ^= invUm._matrix[i][k];
}
}
}
}
// inverse matrix
result[1] = (GF2Matrix)invUm.RightMultiply(invLm.RightMultiply(p));
return(result);
}
private static MaMaPe GetMMP(GF2Matrix H, IRandom SecRnd)
{
int n = H.ColumnCount;
GF2Matrix s = null;
Permutation p = new Permutation(n, SecRnd);
GF2Matrix hp = (GF2Matrix)H.RightMultiply(p);
GF2Matrix sInv = hp.LeftSubMatrix();
if ((s = InvertMatrix(sInv)) == null)
return null;
GF2Matrix shp = (GF2Matrix)s.RightMultiply(hp);
GF2Matrix m = shp.RightSubMatrix();
return new MaMaPe(sInv, m, p);
}
/// <summary>
/// Create a nxn random regular matrix and its inverse
/// </summary>
///
/// <param name="N">Number of rows (and columns)</param>
/// <param name="SecRnd">Source of randomness</param>
/// <returns>The created random regular matrix and its inverse</returns>
public static GF2Matrix[] CreateRandomRegularMatrixAndItsInverse(int N, IRandom SecRnd)
{
GF2Matrix[] result = new GF2Matrix[2];
// First part: create regular matrix
int length = (N + 31) >> 5;
GF2Matrix lm = new GF2Matrix(N, Matrix.MATRIX_TYPE_RANDOM_LT, SecRnd);
GF2Matrix um = new GF2Matrix(N, Matrix.MATRIX_TYPE_RANDOM_UT, SecRnd);
GF2Matrix rm = (GF2Matrix)lm.RightMultiply(um);
Permutation p = new Permutation(N, SecRnd);
int[] pVec = p.GetVector();
int[][] matrix = ArrayUtils.CreateJagged<int[][]>(N, length);
for (int i = 0; i < N; i++)
Array.Copy(rm._matrix[pVec[i]], 0, matrix[i], 0, length);
result[0] = new GF2Matrix(N, matrix);
// Second part: create inverse matrix
// inverse to lm
GF2Matrix invLm = new GF2Matrix(N, Matrix.MATRIX_TYPE_UNIT);
for (int i = 0; i < N; i++)
{
int rest = i & 0x1f;
int q = IntUtils.URShift(i, 5);
int r = 1 << rest;
for (int j = i + 1; j < N; j++)
{
int b = (lm._matrix[j][q]) & r;
if (b != 0)
{
for (int k = 0; k <= q; k++)
invLm._matrix[j][k] ^= invLm._matrix[i][k];
}
}
}
// inverse to um
GF2Matrix invUm = new GF2Matrix(N, Matrix.MATRIX_TYPE_UNIT);
for (int i = N - 1; i >= 0; i--)
{
int rest = i & 0x1f;
int q = IntUtils.URShift(i, 5);
int r = 1 << rest;
for (int j = i - 1; j >= 0; j--)
{
int b = (um._matrix[j][q]) & r;
if (b != 0)
{
for (int k = q; k < length; k++)
invUm._matrix[j][k] ^= invUm._matrix[i][k];
}
}
}
// inverse matrix
result[1] = (GF2Matrix)invUm.RightMultiply(invLm.RightMultiply(p));
return result;
}
/// <summary>
/// Create an nxn random regular matrix
/// </summary>
///
/// <param name="N">Number of rows (and columns)</param>
/// <param name="SecRnd">Source of randomness</param>
private void AssignRandomRegularMatrix(int N, IRandom SecRnd)
{
RowCount = N;
ColumnCount = N;
_length = IntUtils.URShift((N + 31), 5);
_matrix = ArrayUtils.CreateJagged<int[][]>(RowCount, _length);
GF2Matrix lm = new GF2Matrix(N, Matrix.MATRIX_TYPE_RANDOM_LT, SecRnd);
GF2Matrix um = new GF2Matrix(N, Matrix.MATRIX_TYPE_RANDOM_UT, SecRnd);
GF2Matrix rm = (GF2Matrix)lm.RightMultiply(um);
Permutation perm = new Permutation(N, SecRnd);
int[] p = perm.GetVector();
for (int i = 0; i < N; i++)
Array.Copy(rm._matrix[i], 0, _matrix[p[i]], 0, _length);
}
