public KOMatrices KOFunc(HashSet <char> Mkey)
{
Dictionary <char, Tuple <int, int> > KMatrix = new Dictionary <char, Tuple <int, int> >();
List <List <char> > OMatrix = new List <List <char> >();
int counter = 0;
for (int i = 0; i < 5; i++)
{
List <char> tmp = new List <char>();
for (int j = 0; j < 5; j++)
{
if (counter < 25)
{
KMatrix.Add(Mkey.ElementAt(counter), new Tuple <int, int>(i, j));
tmp.Add(Mkey.ElementAt(counter));
counter++;
}
}
OMatrix.Add(tmp);
}
KOMatrices komatrix = new KOMatrices();
komatrix.KM = KMatrix;
komatrix.OM = OMatrix;
return(komatrix);
}
public string Encrypt(string plainText, string key)
{
string CT = "";
KOMatrices KOkey = KOFunc(ModifiedKey(key));
for (int i = 0; i < plainText.Length - 1; i += 2)
{
if (plainText[i] == plainText[i + 1])
{
plainText = plainText.Substring(0, i + 1) + 'x' + plainText.Substring(i + 1);
}
}
if (plainText.Length % 2 == 1)
{
plainText += 'x';
}
int PTLength = plainText.Length;
for (int i = 0; i < PTLength; i += 2)
{
char c1 = plainText[i], c2 = plainText[i + 1];
if (KOkey.KM[c1].Item2 == KOkey.KM[c2].Item2) //same column
{
CT += KOkey.OM[(KOkey.KM[c1].Item1 + 1) % 5][KOkey.KM[c1].Item2];
CT += KOkey.OM[(KOkey.KM[c2].Item1 + 1) % 5][KOkey.KM[c2].Item2];
}
else if (KOkey.KM[c1].Item1 == KOkey.KM[c2].Item1)//same row
{
CT += KOkey.OM[KOkey.KM[c1].Item1][(KOkey.KM[c1].Item2 + 1) % 5];
CT += KOkey.OM[KOkey.KM[c2].Item1][(KOkey.KM[c2].Item2 + 1) % 5];
}
else
{
CT += KOkey.OM[KOkey.KM[c1].Item1][KOkey.KM[c2].Item2];
CT += KOkey.OM[KOkey.KM[c2].Item1][KOkey.KM[c1].Item2];
}
}
Console.WriteLine(CT.ToUpper());
Console.WriteLine("\n\n");
return(CT.ToUpper());
}
public string Decrypt(string cipherText, string key)
{
cipherText = cipherText.ToLower();
List <string> smallSegs = new List <string>();
bool flag = false;
if (cipherText.Length > 100)
{
smallSegs = divideIt(cipherText);
flag = true;
}
KOMatrices matrix = KOFunc(ModifiedKey(key));
string FPT = "";
for (int j = 0; j < smallSegs.Count || !flag; j++)
{
if (flag)
{
cipherText = smallSegs[j];
}
int CTLength = cipherText.Length;
string PT = "";
flag = true;
for (int i = 0; i < CTLength; i += 2)
{
char c1 = cipherText[i], c2 = cipherText[i + 1];
if (matrix.KM[c1].Item2 == matrix.KM[c2].Item2)
{
PT += matrix.OM[(matrix.KM[c1].Item1 + 4) % 5][matrix.KM[c1].Item2];
PT += matrix.OM[(matrix.KM[c2].Item1 + 4) % 5][matrix.KM[c2].Item2];
}
else if (matrix.KM[c1].Item1 == matrix.KM[c2].Item1)
{
PT += matrix.OM[matrix.KM[c1].Item1][(matrix.KM[c1].Item2 + 4) % 5];
PT += matrix.OM[matrix.KM[c2].Item1][(matrix.KM[c2].Item2 + 4) % 5];
}
else
{
PT += matrix.OM[matrix.KM[c1].Item1][matrix.KM[c2].Item2];
PT += matrix.OM[matrix.KM[c2].Item1][matrix.KM[c1].Item2];
}
}
string ans = PT;
if (PT[PT.Length - 1] == 'x')
{
ans = ans.Remove(PT.Length - 1);
}
int w = 0;
for (int i = 0; i < ans.Length; i++)
{
if (PT[i] == 'x')
{
if (PT[i - 1] == PT[i + 1])
{
if (i + w < ans.Length && (i - 1) % 2 == 0)
{
ans = ans.Remove(i + w, 1);
w--;
}
}
}
}
FPT += ans;
}
Console.WriteLine(FPT);
return(FPT);
}