/// <summary>
/// The function returns the black box output bit.
/// </summary>
/// <param name="v">Public variables.</param>
/// <param name="x">Secret variables.</param>
/// <returns>Returns the black box output bit, either 0 or 1.</returns>
public int Blackbox(int[] v, int[] x)
{
int result = 0;
try
{
result = CubeattackBlackbox.GenerateBlackboxOutputBit(v, x, indexOutputBit);
}
catch (Exception ex)
{
stop = true;
CubeAttack_LogMessage("Error: " + ex, NotificationLevel.Error);
}
return(result);
}
} //End PreprocessingPhase
/// <summary>
/// Online phase of the cube attack.
/// </summary>
public void OnlinePhase()
{
if (settings.ReadSuperpolysFromFile)
{
if (File.Exists(settings.OpenFilename))
{
CubeAttack_LogMessage("Read superpolys from file !", NotificationLevel.Info);
superpolyMatrix = new Matrix(settings.SecretVar, settings.SecretVar + 1);
listCubeIndexes = new List <List <int> >();
outputBitIndex = new int[settings.SecretVar];
int i = 0;
foreach (string sLine in File.ReadAllLines(settings.OpenFilename))
{
string[] allValues = sLine.Split(' ');
string[] variables = allValues[0].Split('+');
string[] cubeIndex = allValues[1].Split(',');
List <string> variablesList = new List <string>(variables); // Copy to List
for (int j = 0; j < variablesList.Count; j++)
{
if (variablesList[j].Substring(0, 1) == "1")
{
superpolyMatrix[i, 0] = 1;
variablesList.Remove(variablesList[j]);
}
}
for (int j = 0; j < variablesList.Count; j++)
{
if (variablesList[j].Substring(0, 1) == "x")
{
variablesList[j] = variablesList[j].Substring(1);
}
}
List <int> superpoly = new List <int>();
for (int j = 0; j < variablesList.Count; j++)
{
superpoly.Add(Convert.ToInt32(variablesList[j]));
}
for (int j = 0; j < superpoly.Count; j++)
{
superpolyMatrix[i, superpoly[j] + 1] = 1;
}
List <int> maxterm = new List <int>();
foreach (string cube in cubeIndex)
{
maxterm.Add(Convert.ToInt32(cube));
}
listCubeIndexes.Add(maxterm);
outputBitIndex[i] = Convert.ToInt32(allValues[2]);
i++;
// Save number of input superpolys
countSuperpoly = i;
}
}
else
{
CubeAttack_LogMessage("Please input a File", NotificationLevel.Error);
return;
}
}
if (superpolyMatrix == null || listCubeIndexes == null)
{
CubeAttack_LogMessage("Preprocessing phase has to be executed first", NotificationLevel.Error);
}
else
{
CubeAttack_LogMessage("Start online phase", NotificationLevel.Info);
outputSuperpoly = string.Empty;
int[] pubVarElement = new int[settings.PublicVar];
if (pubVarGlob != null)
{
for (int i = 0; i < settings.PublicVar; i++)
{
pubVarElement[i] = pubVarGlob[i];
}
}
Vector b = new Vector(settings.SecretVar);
for (int i = 0; i < listCubeIndexes.Count; i++)
{
List <int> superpoly = new List <int>();
for (int j = 1; j < superpolyMatrix.Cols; j++)
{
superpoly.Add(superpolyMatrix[i, j]);
}
CubeAttack_LogMessage("Compute value of superpoly " + SuperpolyAsString(superpoly), NotificationLevel.Info);
for (ulong k = 0; k < Math.Pow(2, listCubeIndexes[i].Count); k++)
{
if (stop)
{
return;
}
for (int l = 0; l < listCubeIndexes[i].Count; l++)
{
pubVarElement[listCubeIndexes[i][l]] = (k & ((ulong)1 << l)) > 0 ? 1 : 0;
}
try
{
b[i] ^= CubeattackBlackbox.GenerateBlackboxOutputBit(pubVarElement, null, outputBitIndex[i]);
}
catch (Exception ex)
{
CubeAttack_LogMessage("Error: " + ex, NotificationLevel.Error);
}
}
for (int j = 0; j < settings.PublicVar; j++)
{
pubVarElement[j] = 0;
}
outputSuperpoly += GetLogMessage(listCubeIndexes[i], superpoly, outputBitIndex[i], b[i]);
OnPropertyChanged("OutputSuperpoly");
ProgressChanged((double)i / (double)listCubeIndexes.Count, 1.0);
outputSuperpoly = string.Empty;
}
if (listCubeIndexes.Count == settings.SecretVar)
{
CubeAttack_LogMessage("Solve system of equations", NotificationLevel.Info);
for (int i = 0; i < settings.SecretVar; i++)
{
b[i] ^= superpolyMatrix[i, 0];
}
// Delete first column and invert
OutputKey(superpolyMatrix.DeleteFirstColumn().Inverse() * b);
OnPropertyChanged("OutputKeyBits");
CubeAttack_LogMessage("Key bits successfully discovered, online phase completed", NotificationLevel.Info);
}
else
{
CubeAttack_LogMessage("Not enough linearly independent superpolys have been found in the preprocessing to discover all secret bits !", NotificationLevel.Info);
}
}
}