public string decrypt()
{
Des D3 = new Des(keys[2], input, mode);
Des D2 = new Des(keys[1], D3.decode().Replace("-", ""), mode);
Des D1 = new Des(keys[0], D2.Encode().Replace("-", ""), mode);
return(D1.decode());
}
private bool everythingIsFine()
{
if (rdioCeasar.Checked)
{
try{
int.Parse(txtKey.Text);
} catch {
showMessage("Wrong key", "Key must be integer in Ceasar.");
return(false);
}
}
else if (rdioPlayfair.Checked)
{
//TODO: Check for out-of-alphabet characters in key.
}
else if (rdioMonoalphabetic.Checked && txtKey.Text.Length != 26)
{
showMessage("Wrong key", "Key must be of exact 26 characters in Monoalphabetic.");
return(false);
}
else if (rdioHill.Checked && txtKey.Text.Length != 4)
{
showMessage("Wrong key", "Key must be of exact 4 characters (2x2) in Hill.");
return(false);
}
else if (rdioRailFence.Checked)
{
try{
int.Parse(txtKey.Text);
} catch {
showMessage("Wrong key", "Key must be an integer in Rail Fence.");
return(false);
}
}
else if (rdioColumnar.Checked)
{
try{
Helpers.getIntArray(txtKey.Text);
} catch {
showMessage("Wrong key", "Key must be an array of integers, separated by spaces in Columnar.");
return(false);
}
}
else if (rdioDES.Checked)
{
try{
Des.HexToByteArray(Helpers.removeDashes(txtKey.Text));
} catch {
showMessage("Wrong key", "Key must be a valid hex value in DES.");
return(false);
}
try{
Des.HexToByteArray(Helpers.removeDashes(txtPlaintext.Text));
} catch {
showMessage("Wrong key", "Plaintext must be a valid hex value in DES.");
return(false);
}
if (Helpers.removeDashes(txtKey.Text).Length != 16)
{
showMessage("Wrong key", "Key must be a hex of exact 16 digit in DES.");
return(false);
}
}
else if (rdioTripleDES.Checked)
{
string[] keys = txtKey.Text.Split(' ');
if (keys.Length != 3)
{
showMessage("Wrong key", "Key must consist of 3 hex keys separated by spaces in Triple-DES.");
return(false);
}
try{
foreach (string key in keys)
{
Des.HexToByteArray(Helpers.removeDashes(key));
}
} catch {
showMessage("Wrong key", "Each key must be a valid hex value in DES.");
return(false);
}
try{
Des.HexToByteArray(Helpers.removeDashes(txtPlaintext.Text));
} catch {
showMessage("Wrong key", "Plaintext must be a valid hex value in DES.");
return(false);
}
foreach (string key in keys)
{
if (Helpers.removeDashes(key).Length != 16)
{
showMessage("Wrong key", "Each key must be a hex of exact 16 digit in DES.");
return(false);
}
}
}
//TODO: Check when (key.Length == 0) for algorithms that require that.
return(true);
}