bool checkP(Matrix Gp, Matrix P1_inv, Ham ham, Matrix Zero, int s, int n)
{
bool result = true;
for (int i = 0; i < s - 1; ++i)
{
result &= MatrixFuncs.SubMatrix(Gp * P1_inv, i * n, (i + 1) * n) * MatrixFuncs.Transp(ham.H) == Zero;
}
return(result);
}
public double AttackHam(out List <Matrix> Nlist, out Matrix P1)
{
int k = Gp.size[0], nn = Gp.size[1];
Nlist = new List <Matrix>(); P1 = new Matrix(nn, nn);
int r = (int)Math.Log((nn + 2) / 2, 2);
int tmp = nn % ((1 << r) - 1), s;
while (tmp != 0)
{
--r;
tmp = nn % ((1 << r) - 1);
}
s = nn / ((1 << r) - 1); int n = nn / s;
Matrix Ni = new Matrix(k, k); P1 = new Matrix(nn, nn); Matrix P1_inv = new Matrix(nn, nn);
Code code = new Code(Gp);
Ham ham = new Ham(r);
Stopwatch t = new Stopwatch(); t.Start();
// Matrix P1
List <int>[] ham_idx = GetHamIndices(code, ham, r, s, n, k);
Matrix Zero = new Matrix(k, n - k);
BigInteger iter_count = 0, max_iter_num = 1, ind_count = 0;
List <int>[] idx_copy = new List <int> [n]; int[][] indices = new int[s][];
for (int i = 0; i < s; ++i)
{
indices[i] = new int[n];
max_iter_num = BigInteger.Multiply(max_iter_num, BigInteger.Pow(s - i, n));
}
do
{
++iter_count; ++ind_count;
if (iter_count > max_iter_num)
{
ham_idx = GetHamIndices(code, ham, r, s, n, k);
for (int i = 0; i < s; ++i)
{
indices[i] = new int[n];
}
iter_count = 1; ind_count = 1;
}
idx_copy = ham_idx.Select(x => new List <int>(x)).ToArray();
P1 = new Matrix(nn, nn); P1_inv = new Matrix(nn, nn);
for (int i = 0; i < s; i++)
{
for (int j = 0; j < n; ++j)
{
P1.data[i * n + j][idx_copy[j][indices[i][j]]] = 1;
P1_inv.data[idx_copy[j][indices[i][j]]][i * n + j] = 1;
idx_copy[j].RemoveAt(indices[i][j]);
}
}
Common.NextSet(indices[0], s, n);
if (ind_count == BigInteger.Pow(s, n))
{
indices[0] = new int[n];
Common.NextSet(indices[1], s - 1, n);
ind_count = 0;
}
} while (checkP(Gp, P1_inv, ham, Zero, s, n) == false);
// Matrices N
Matrix NG = Gp * P1_inv;
for (int i = 0; i < s; ++i)
{
Ni = MatrixFuncs.SolveEq(MatrixFuncs.Transp(ham.G), MatrixFuncs.Transp(MatrixFuncs.SubMatrix(NG, i * n, (i + 1) * n)));
var ttt = MatrixFuncs.Transp(Ni) * ham.G == MatrixFuncs.SubMatrix(NG, i * n, (i + 1) * n);
Nlist.Add(MatrixFuncs.Transp(Ni));
}
NG = new Matrix();
for (int i = 0; i < Nlist.Count; ++i)
{
NG |= Nlist[i] * ham.G;
}
t.Stop();
return(t.ElapsedMilliseconds / 1000.00);
}