private void buttonCrypto_Click(object sender, EventArgs e)
{
string cipher,substring,tempstring="";
int indexfirst,indexlast,i,j,k,a,b;
List<int> distList = new List<int>();
List<Nod> NodList = new List<Nod>();
Nod currentnod=new Nod();
bool check;
if (textBox_Cipher.Lines.Count() == 0)
{
MessageBox.Show("Не введен шифротекст!");
return;
}
textBox_Source.Clear();
cipher = textBox_Cipher.Text.ToString();
for (indexfirst = 0; indexfirst < cipher.Length; indexfirst++)
{
if (Array.IndexOf(Alphabet, cipher[indexfirst]) == -1)
{
cipher = cipher.Remove(indexfirst, 1);
indexfirst--;
}
}
for (int length = 10; length >= 3; length--)
{
for (indexfirst = 0; indexfirst < cipher.Length-length; indexfirst++)
{
substring = cipher.Substring(indexfirst,length);
if ((textBox_Source.Text.IndexOf(substring) == -1) && (textBox_Source.Text.IndexOf(substring.Substring(0,3)) == -1))
{
tempstring = "";
indexlast = indexfirst + length - 1;
while (indexlast > -1)
{
indexlast = cipher.IndexOf(substring, indexlast + 1);
if (indexlast > -1)
{
tempstring = tempstring + "pos=" + indexlast + " dist=" + (indexlast - indexfirst) + "; ";
distList.Add(indexlast - indexfirst);
}
}
if (tempstring != "")
textBox_Source.AppendText("\"" + substring + "\" " + "starting pos=" + indexfirst + " " + tempstring + "\r\n");
}
}
}
distList.Sort();
for (i = 1; i < distList.Count; i++)
{
if (distList[i] == distList[i - 1])
{
distList.RemoveAt(i);
i--;
}
}
for (i = 0; i < distList.Count; i++)
{
for (j = i+1; j < distList.Count; j++)
{
check = true;
a = distList[i];
b = distList[j];
while ((a!=0) && (b!=0))
{
if (a > b)
a = a % b;
else
b = b % a;
}
currentnod.value=a+b;
currentnod.chance=1;
if (currentnod.value == 1)
continue;
for (k = 0; k < NodList.Count; k++)
{
if (NodList[k].value == currentnod.value)
{
check = false;
currentnod = NodList[k];
currentnod.chance++;
NodList[k] = currentnod;
break;
}
}
if (check)
NodList.Add(currentnod);
}
}
indexfirst = 0;
currentnod = NodList[0];
for (i = 0; i < NodList.Count; i++)
{
indexfirst+=NodList[i].chance;
if (NodList[i].chance>currentnod.chance)
currentnod = NodList[i];
}
textBox_Source.AppendText("Криптоанализ завершен!\r\n");
textBox_Source.AppendText("Вероятная длинна ключа: "+currentnod.value+". Вероятность: "+(currentnod.chance*100/indexfirst)+"%\r\n");
}