private void generateRSAButton_Click(object sender, EventArgs e)
{
getSessionKeyButton.Enabled = true;
generateRSAButton.Enabled = false;
keyPair = new RSAKeyPair();
var serialized = Serializer.SerializeKey(keyPair.privateKey) + "$";
var keyPairEncrypted = AES.Encrypt(Encoding.UTF8.GetBytes(serialized), masterAESKey, masterAESIV);
File.WriteAllBytes("RSAKey.bin", keyPairEncrypted);
}
private void getTextButton_Click(object sender, EventArgs e)
{
var filename = filenameBox.Text;
filename = "first.txt";
var filenameArray = AES.Encrypt(Encoding.UTF8.GetBytes(filename), sessionAESKey, sessionAESIV);
if (filename.Length != 0)
{
connection.Send(TCPConnection.FILENAME, filenameArray);
}
}
private void sendTextButton_Click(object sender, EventArgs e)
{
if (filenameBox.Text.Length != 0)
{
var text = AES.Encrypt(Encoding.Default.GetBytes(textBox1.Text), sessionAESKey, sessionAESIV);
var filename = AES.Encrypt(Encoding.Default.GetBytes(filenameBox.Text), sessionAESKey, sessionAESIV);
var filenameLength = BitConverter.GetBytes(filename.Length);
var msg = new byte[4 + filename.Length + text.Length];
Array.Copy(filenameLength, 0, msg, 0, 4);
Array.Copy(filename, 0, msg, 4, filename.Length);
Array.Copy(text, 0, msg, 4 + filename.Length, text.Length);
connection.Send(TCPConnection.TEXT, msg);
}
}
private void SendLogin(TcpClient client, string login, string password)
{
login = textBoxLogin.Text;
password = textBoxPassword.Text;
byte[] loginEcnr = AES.Encrypt(Encoding.Default.GetBytes(login), sessionAESKey, sessionAESIV);
byte[] passwordEcnr = AES.Encrypt(Encoding.Default.GetBytes(password), sessionAESKey, sessionAESIV);
var loginLen = BitConverter.GetBytes(loginEcnr.Length);
var msg = new byte[4 + loginEcnr.Length + passwordEcnr.Length];
Array.Copy(loginLen, 0, msg, 0, 4);
Array.Copy(loginEcnr, 0, msg, 4, loginEcnr.Length);
Array.Copy(passwordEcnr, 0, msg, 4 + loginEcnr.Length, passwordEcnr.Length);
connection.Send(TCPConnection.LOGIN, msg);
}
private void generateQrCode(byte[] key)
{
Totp totp = new Totp(key);
string totpCode = totp.ComputeTotp(DateTime.UtcNow);
QRCodeGenerator qr = new QRCodeGenerator();
var secret = "otpauth://totp/Example:" + login + "?secret=" + Base32Encoding.ToString(key) + "&issuer=Example";
QRCodeData qrData = qr.CreateQrCode(secret, QRCodeGenerator.ECCLevel.Q);
QRCode code = new QRCode(qrData);
QRCodeForm qrForm = new QRCodeForm();
qrForm.QRPic = code.GetGraphic(2);
qrForm.ShowDialog();
var codeFromUser = qrForm.Password;
connection.Send(TCPConnection.QR_PASS_FROM_USER, AES.Encrypt(Encoding.UTF8.GetBytes(codeFromUser), sessionAESKey, sessionAESIV));
}
private void ReceiveResponseFromServerAsync()
{
Task.Factory.StartNew(() =>
{
while (true)
{
int messageType;
try
{
messageType = BitConverter.ToInt32(connection.Receive(4), 0);
}
catch (IOException e)
{
Invoke((MethodInvoker) delegate
{
toggleLoginForm(false);
blocknote.Visible = false;
getSessionKeyButton.Enabled = true;
serverResponses.Visible = true;
serverResponses.Text = "session has been expired";
});
break;
}
var lenBytes = BitConverter.ToInt32(connection.Receive(4), 0);
Invoke((MethodInvoker) delegate
{
serverResponses.Visible = false;
});
byte[] msg = connection.Receive(lenBytes);
if (messageType == TCPConnection.ENCRYPTED_AES_WITH_RSA)
{
sessionAESKey = new byte[128];
Array.Copy(msg, 0, sessionAESKey, 0, 128);
sessionAESKey = keyPair.Decrypt(sessionAESKey);
sessionAESIV = new byte[128];
Array.Copy(msg, 128, sessionAESIV, 0, 128);
sessionAESIV = keyPair.Decrypt(sessionAESIV);
Invoke((MethodInvoker) delegate
{
getSessionKeyButton.Enabled = false;
});
}
else if (messageType == TCPConnection.LOGIN_APPROVED)
{
Invoke((MethodInvoker) delegate
{
toggleLoginForm(false);
loginRejected.Visible = false;
blocknote.Visible = true;
});
}
else if (messageType == TCPConnection.LOGIN_REJECTED)
{
Invoke((MethodInvoker) delegate
{
toggleLoginForm(true);
loginRejected.Visible = true;
});
}
else if (messageType == TCPConnection.TEXT)
{
var text = Encoding.UTF8.GetString(AES.Decrypt(msg, sessionAESKey, sessionAESIV));
Invoke((MethodInvoker) delegate
{
textBox1.Text = text;
});
}
else if (messageType == TCPConnection.FILE_DO_NOT_EXISTS)
{
Invoke((MethodInvoker) delegate
{
serverResponses.Visible = true;
serverResponses.Text = "file with such a filename does not exist";
});
}
else if (messageType == TCPConnection.FILE_SAVED)
{
Invoke((MethodInvoker) delegate
{
serverResponses.Visible = true;
serverResponses.Text = "file was saved";
});
}
else if (messageType == TCPConnection.QR_CODE_GENERATED)
{
var key = AES.Decrypt(msg, sessionAESKey, sessionAESIV);
generateQrCode(key);
}
else if (messageType == TCPConnection.USE_OLD_KEY)
{
QRCodeForm qrForm = new QRCodeForm();
qrForm.ShowDialog();
var codeFromUser = qrForm.Password;
connection.Send(TCPConnection.QR_PASS_FROM_USER, AES.Encrypt(Encoding.UTF8.GetBytes(codeFromUser), sessionAESKey, sessionAESIV));
}
else
{
break;
}
}
});
}