//supplementary methods
private static double[,] CalculateInverseMatrix()
{
double[,] inverseMatrix = new double[3, 3];
inverseMatrix[0, 0] = (cryptoMatrix[1, 1] * cryptoMatrix[2, 2]) - (cryptoMatrix[1, 2] * cryptoMatrix[2, 1]);
inverseMatrix[0, 1] = (cryptoMatrix[1, 2] * cryptoMatrix[2, 0]) - (cryptoMatrix[1, 0] * cryptoMatrix[2, 2]);
inverseMatrix[0, 2] = (cryptoMatrix[1, 0] * cryptoMatrix[2, 1]) - (cryptoMatrix[1, 1] * cryptoMatrix[2, 0]);
inverseMatrix[1, 0] = (cryptoMatrix[0, 2] * cryptoMatrix[2, 1]) - (cryptoMatrix[0, 1] * cryptoMatrix[2, 2]);
inverseMatrix[1, 1] = (cryptoMatrix[0, 0] * cryptoMatrix[2, 2]) - (cryptoMatrix[0, 2] * cryptoMatrix[2, 0]);
inverseMatrix[1, 2] = (cryptoMatrix[0, 1] * cryptoMatrix[2, 0]) - (cryptoMatrix[0, 0] * cryptoMatrix[2, 1]);
inverseMatrix[2, 0] = (cryptoMatrix[0, 1] * cryptoMatrix[1, 2]) - (cryptoMatrix[0, 2] * cryptoMatrix[1, 1]);
inverseMatrix[2, 1] = (cryptoMatrix[0, 2] * cryptoMatrix[1, 0]) - (cryptoMatrix[0, 0] * cryptoMatrix[1, 2]);
inverseMatrix[2, 2] = (cryptoMatrix[0, 0] * cryptoMatrix[1, 1]) - (cryptoMatrix[0, 1] * cryptoMatrix[1, 0]);
for (int i = 0; i < 3; i++)
{
for (int j = i + 1; j < 3; j++)
{
Universal.Swap(ref inverseMatrix[i, j], ref inverseMatrix[j, i]);
}
}
double m1 = cryptoMatrix[0, 0] * ((cryptoMatrix[1, 1] * cryptoMatrix[2, 2]) - (cryptoMatrix[1, 2] * cryptoMatrix[2, 1]));
double m2 = cryptoMatrix[0, 1] * ((cryptoMatrix[1, 0] * cryptoMatrix[2, 2]) - (cryptoMatrix[1, 2] * cryptoMatrix[2, 0]));
double m3 = cryptoMatrix[0, 2] * ((cryptoMatrix[1, 0] * cryptoMatrix[2, 1]) - (cryptoMatrix[1, 1] * cryptoMatrix[2, 0]));
double determinant = m1 - m2 + m3;
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 3; j++)
{
inverseMatrix[i, j] /= determinant;
}
}
return(inverseMatrix);
}
