// Function to decrypt the image
private string DecryptImage(string imageToDecryptHex)
{
var ImageHex = imageToDecryptHex.ToCharArray();
var i = 0;
var decryptResponse = "";
ProgressBar_decrypt.Maximum = ImageHex.Length;
try
{
for (; i < ImageHex.Length; i++)
{
Application.DoEvents();
var c = "";
ProgressBar_decrypt.Value = i;
int temp;
for (temp = i; ImageHex[temp] != '-'; temp++)
{
c = c + ImageHex[temp];
}
i = temp;
var xx = Convert.ToInt32(c);
decryptResponse = decryptResponse + (char)RSAalgorithm.BigMod(xx, _d, _n);
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
return(decryptResponse);
}
private void SendKeyButtonOnClick(object sender, EventArgs e)
{
var ip = GetIpAddress();
Selector_decrypt.Enabled = true;
if (Button_sendPublicKey.Text == "Send Public Key")
{
if (prime1TextBox.Text == "" || prime2TextBox.Text == "" || ETextBox.Text == "")
{
MessageBox.Show("Enter Valid Details For RSA", "ERROR");
}
else
{
if (HelperLibrary.IsPrime(Convert.ToInt16(prime1TextBox.Text)))
{
_rsaP = Convert.ToInt16(prime1TextBox.Text);
}
else
{
prime1TextBox.Text = "";
MessageBox.Show("Enter Prime Number");
return;
}
if (HelperLibrary.IsPrime(Convert.ToInt16(prime2TextBox.Text)))
{
_rsaQ = Convert.ToInt16(prime2TextBox.Text);
}
else
{
prime2TextBox.Text = "";
MessageBox.Show("Enter Prime Number");
return;
}
_rsaE = Convert.ToInt16(ETextBox.Text);
// Help taken from SO
// Calculating Private Key
_n = RSAalgorithm.n_value(_rsaP, _rsaQ);
var phi = RSAalgorithm.cal_phi(_rsaP, _rsaQ);
_d = RSAalgorithm.cal_privateKey(phi, _rsaE, _n);
MessageBox.Show(
"Please Connect to the server IP : " + ip + "\nPublic Key = (" + _rsaE + " ," + _n +
")\nPrivate Key = (" + _d + "," + _n + ")", "Alert");
Button_sendPublicKey.Text = "Receive";
// Sending Public key
Console.WriteLine("Sending public key");
File.WriteAllText("Key.txt", _rsaE + "+" + _n);
MessageBox.Show("Sending Public key");
}
}
else
{
MessageBox.Show("Public Key integrity check passed.");
}
}
// Function to encrypt the image
private string EncryptImage(string imageHexToEncrypt)
{
MessageBox.Show("RSA_E = " + _rsaE + "\nn = " + _n);
var imageHex = imageHexToEncrypt;
var imageHexArray = imageHex.ToCharArray();
var cond = "";
Progressbar_encryptImage.Maximum = imageHexArray.Length;
for (var i = 0; i < imageHexArray.Length; i++)
{
Application.DoEvents();
Progressbar_encryptImage.Value = i;
if (cond == "")
{
cond = cond + RSAalgorithm.BigMod(imageHexArray[i], _rsaE, _n);
}
else
{
cond = cond + "-" + RSAalgorithm.BigMod(imageHexArray[i], _rsaE, _n);
}
}
return(cond);
}
