private void AddUser()
{
var serviceRSA = new ServiceRSA();
var serviceAES = new ServiceAES(CipherMode.ECB, userPassTB.Text, false);
var IV = serviceAES.GetIV();
var encryptedPrivKey = serviceAES.Encrypt(serviceRSA.ParamsKeyToString(serviceRSA.ParamsPrivKey));
var publicKey = serviceRSA.ParamsKeyToString(serviceRSA.ParamsPubKey);
using (StreamWriter file =
new StreamWriter(@"..\..\users\privateKeys\" + usernameTB.Text + ".txt", true))
{
file.Write(encryptedPrivKey);
}
using (StreamWriter file =
new StreamWriter(@"..\..\users\publicKeys\" + usernameTB.Text + ".txt", true))
{
file.Write(publicKey);
}
using (StreamWriter file =
new StreamWriter(@"..\..\users\vectorsIV\" + usernameTB.Text + ".txt", true))
{
file.Write(IV);
}
}
private void Decrypt_Click(object sender, EventArgs e)
{
decryptMessageLabel.Show();
this.decryptMessageLabel.ForeColor = Color.Orange;
this.decryptMessageLabel.Text = "Decryption in progress";
if (outputFilenameTB.Text.Equals(string.Empty))
{
this.decryptMessageLabel.ForeColor = Color.Red;
this.decryptMessageLabel.Text = "Decryption failed";
progressBar.Hide();
MessageBox.Show("No output filename was chosen");
return;
}
if (fileTB.Text.Equals(string.Empty))
{
this.decryptMessageLabel.ForeColor = Color.Red;
this.decryptMessageLabel.Text = "Decryption failed";
progressBar.Hide();
MessageBox.Show("No input file was chosen");
return;
}
if (approvedUsersCB.Text.Equals(string.Empty))
{
this.decryptMessageLabel.ForeColor = Color.Red;
this.decryptMessageLabel.Text = "Decryption failed";
progressBar.Hide();
MessageBox.Show("No user was chosen");
return;
}
if (userPassTB.Text.Equals(string.Empty))
{
this.decryptMessageLabel.ForeColor = Color.Red;
this.decryptMessageLabel.Text = "Decryption failed";
progressBar.Hide();
MessageBox.Show("Incorrect password");
return;
}
var encryptedFileContent = File.ReadAllText(fileTB.Text);
var XMLStringMetadata = encryptedFileContent.Split(new[] { "</EncryptedFileHeader>" }, StringSplitOptions.None)[0] + "</EncryptedFileHeader>";
var encyptedData = encryptedFileContent.Split(new[] { "</EncryptedFileHeader>" }, StringSplitOptions.None)[1];
var doc = new XmlDocument();
doc.LoadXml(XMLStringMetadata);
XmlNodeList approvedUserNodes = doc.SelectNodes("/EncryptedFileHeader/ApprovedUsers/User");
var decryptionMode = doc.SelectSingleNode("/EncryptedFileHeader/CipherMode").InnerText;
var fileIV = doc.SelectSingleNode("/EncryptedFileHeader/IV").InnerText;
CipherMode mode = 0;
var cipherMode = decryptionMode;
if (cipherMode == "ECB")
{
mode = CipherMode.ECB;
}
else if (cipherMode == "CBC")
{
mode = CipherMode.CBC;
}
else if (cipherMode == "CFB")
{
mode = CipherMode.CFB;
}
this.decryptMessageLabel.ForeColor = Color.Red;
this.decryptMessageLabel.Text = "Decryption failed"; //this message is needed, when the user choose receiver that is not in the header of the file
foreach (XmlNode node in approvedUserNodes)
{
if (approvedUsersCB.Text == node.SelectSingleNode("Email").InnerText)
{
progressBar.Show();
if (backgroundWorker1.IsBusy != true)
{
// Start the asynchronous operation.
backgroundWorker1.RunWorkerAsync();
}
var encryptedSessionKey = node.SelectSingleNode("SessionKey").InnerText;
string encryptedPrivKey, userIV;
using (StreamReader sr = new StreamReader(@"..\..\users\privateKeys\" + approvedUsersCB.Text + ".txt"))
{
encryptedPrivKey = sr.ReadToEnd();
}
using (StreamReader sr = new StreamReader(@"..\..\users\vectorsIV\" + approvedUsersCB.Text + ".txt"))
{
userIV = sr.ReadToEnd();
}
var serviceAESDecr = new ServiceAES(CipherMode.ECB, userPassTB.Text, true);
var privKey = serviceAESDecr.Decrypt(encryptedPrivKey, Convert.FromBase64String(userIV));
var serviceRSADecr = new ServiceRSA(privKey, true);
var sessionKey = serviceRSADecr.DecryptSessionKey(encryptedSessionKey);
var extensionOfFile = Path.GetExtension(doc.SelectSingleNode("/EncryptedFileHeader/Extension").InnerText);
var dirToSave = fileTB.Text.Substring(0, fileTB.Text.LastIndexOf("\\") + 1);
var outputFileName = dirToSave + outputFilenameTB.Text + extensionOfFile;
File.WriteAllText(Path.GetFullPath(outputFileName), // START DECRYPTING
ServiceRijndaelAES.DecryptStringFromBytes(
Convert.FromBase64String(encyptedData),
Convert.FromBase64String(sessionKey),
Convert.FromBase64String(fileIV), mode));
this.decryptMessageLabel.ForeColor = Color.Green;
this.decryptMessageLabel.Text = "Decryption suceeded";
}
}
}
