static string decrypt(String encryptedString, Playfair cipher)
{
encryptedString = encryptedString.ToLower();
string decryptedString = null;
List <Plain> listPlains = new List <Plain>();
for (int c = 1; c < encryptedString.Length; c++)
{
if (c % 2 == 1)
{
Plain plain = new Plain();
plain.setval1(encryptedString[c - 1]);
plain.setval2(encryptedString[c]);
listPlains.Add(plain);
}
}
List <Plain> listDecrypted = new List <Plain>();
foreach (Plain p in listPlains)
{
p.findCoordinates(cipher);
if (p.getx1() == p.getx2()) //ten sam wiersz
{
if (p.gety1() == 0)
{
p.sety2(p.gety2() - 1);
p.sety1(4);
}
else if (p.gety2() == 0)
{
p.sety2(4);
p.sety1(p.gety2() - 1);
}
else
{
p.sety1(p.gety1() - 1);
p.sety2(p.gety2() - 1);
}
}
else if (p.gety1() == p.gety2()) //ta sama kolumna
{
if (p.getx2() == 0)
{
p.setx2(4);
p.setx1(p.getx1() - 1);
}
else if (p.getx1() == 0)
{
p.setx2(p.getx2() - 1);
p.setx1(4);
}
else
{
p.setx1(p.getx1() - 1);
p.setx2(p.getx2() - 1);
}
}
else ///reszta
{
int buf = p.gety1();
p.sety1(p.gety2());
p.sety2(buf);
}
p.findCipherLetters(cipher);
listDecrypted.Add(p);
}
foreach (Plain p in listDecrypted)
{
decryptedString = decryptedString + string.Join("", p.getval1().ToString()) + string.Join("", p.getval2().ToString());
}
for (int c = 1; c < decryptedString.Length - 1; c++)
{
if (c > 0 && c < decryptedString.Length)
{
if (decryptedString[c] == 'x' && decryptedString[c - 1] == decryptedString[c + 1])
{
decryptedString = decryptedString.Replace("x", "");
}
}
}
return(decryptedString);
}
static string encrypt(String text, Playfair cipher)
{
text = text.ToLower();
ArrayList list = new ArrayList();
if (text[0] == 'j')
{
list.Add('i');
}
else
{
list.Add(text[0]);
}
for (int c = 1; c < text.Length; c++)
{
if (text[c] == ' ' || text[c] == ',' || text[c] == '.' || text[c] == '?' || text[c] == '!' || text[c] == ':' || text[c] == ';' || text[c] == '*' || text[c] == '(' || text[c] == ')' || text[c] == '"' || text[c] == '\n')
{
}
else if (text[c] == 'j')
{
list.Add('i');
}
else
{
list.Add(text[c]);
}
}
for (int c = 1; c < list.Count; c++)
{
if (list[c - 1].ToString() == list[c].ToString())
{
list.Insert(c, 'x');
}
}
if ((list.Count - 1) % 2 == 0)
{
list.Add('x');
}
String plaintext = string.Join("", list.ToArray());
// Console.WriteLine("Plaintext: " + plaintext);
List <Plain> listPlains = new List <Plain>();
for (int c = 1; c < plaintext.Length; c++)
{
if (c % 2 == 1)
{
Plain plain = new Plain();
plain.setval1(plaintext[c - 1]);
plain.setval2(plaintext[c]);
listPlains.Add(plain);
}
}
List <Plain> listEncrypted = new List <Plain>();
foreach (Plain p in listPlains)
{
p.findCoordinates(cipher);
if (p.getx1() == p.getx2()) //ten sam wiersz
{
if (p.gety1() == 4)
{
p.sety2(p.gety2() + 1);
p.sety1(0);
}
else if (p.gety2() == 4)
{
p.sety2(0);
p.sety1(p.gety2() + 1);
}
else
{
p.sety1(p.gety1() + 1);
p.sety2(p.gety2() + 1);
}
}
else if (p.gety1() == p.gety2()) //ta sama kolumna
{
if (p.getx2() == 4)
{
p.setx2(0);
p.setx1(p.getx1() + 1);
}
else if (p.getx1() == 4)
{
p.setx2(p.getx2() + 1);
p.setx1(0);
}
else
{
p.setx1(p.getx1() + 1);
p.setx2(p.getx2() + 1);
}
}
else ///reszta
{
int buf = p.gety1();
p.sety1(p.gety2());
p.sety2(buf);
}
p.findCipherLetters(cipher);
listEncrypted.Add(p);
}
String encryptedString = null;
foreach (Plain p in listEncrypted)
{
encryptedString = encryptedString + string.Join("", p.getval1().ToString()) + string.Join("", p.getval2().ToString());
}
return(encryptedString);
}
