/// <summary>
/// Reads and decrypts a file THAT IS ENCRYPTED WITH <see cref="AesGcmEncrypt(FileInfo,FileInfo,byte[],int)"/>
/// </summary>
/// <param name="input">The input file to decrypt it</param>
/// <param name="output">The output file to write the decrypted data into it</param>
/// <param name="key">Encryption key</param>
public static void AesGcmDecrypt(FileInfo input, FileInfo output, byte[] key)
{
using (Stream reader = input.OpenRead())
using (Stream writer = output.OpenWrite())
{
int bufferSize;
byte[] fileKey;
// at first read the crypt buffer
{
byte[] buffer = new byte[4];
reader.Read(buffer, 0, buffer.Length);
bufferSize = SharedStuff.BytesToInt(buffer);
bufferSize += 12 + 16;
}
// now read the key that is used to encrypt this file
{
byte[] buffer = new byte[12 + 32 + 16];
reader.Read(buffer, 0, buffer.Length);
fileKey = AesGcmDecrypt(buffer, key);
}
// now read the input file; "bufferSize" bytes at a time
int readCount;
byte[] readBytes = new byte[bufferSize];
while ((readCount = reader.Read(readBytes, 0, readBytes.Length)) > 0)
{
if (readBytes.Length > readCount)
{
Array.Resize(ref readBytes,
readCount); // this is the last chunk of file; Do not decrypt all of the data in readBytes
}
byte[] decrypted = AesGcmDecrypt(readBytes, fileKey);
writer.Write(decrypted, 0, decrypted.Length);
}
}
}
/// <summary>
/// Encrypts a file with AesGcm
/// </summary>
/// <param name="input">The input file to encrypt</param>
/// <param name="output">Output file to write the encrypted file</param>
/// <param name="key">The key to encrypt data with it</param>
/// <param name="bufferSize">The buffer size that the input is read and encrypted</param>
public static void AesGcmEncrypt(FileInfo input, FileInfo output, byte[] key, int bufferSize)
{
byte[] nonce = new byte[12];
byte[] tag = new byte[16];
using (Stream reader = input.OpenRead())
using (Stream writer = output.OpenWrite())
{
// at first write the buffer size to first of file
writer.Write(SharedStuff.IntToBytes(bufferSize), 0, 4); // int is 4 bytes
// generate a key for encryption
byte[] fileKey = new byte[32];
SharedStuff.SecureRandom.GetBytes(fileKey);
SharedStuff.SecureRandom.GetBytes(nonce);
{
byte[] keyToWrite = AesGcmEncrypt(fileKey, key, nonce);
writer.Write(keyToWrite, 0, keyToWrite.Length);
Array.Clear(keyToWrite, 0, keyToWrite.Length);
}
// now read the input file; "bufferSize" bytes at a time
int readCount;
byte[] readBytes = new byte[bufferSize];
while ((readCount = reader.Read(readBytes, 0, readBytes.Length)) > 0)
{
if (readBytes.Length > readCount)
{
Array.Resize(ref readBytes,
readCount); // this is the last chunk of file; Do not encrypt all of the data in readBytes
}
//byte[] crypted = AesGcmEncrypt(readBytes, key); -> Do not use this because Concat takes a lot of time
SharedStuff.SecureRandom.GetBytes(nonce);
byte[] encrypted = AESGCM.GcmEncrypt(readBytes, fileKey, nonce, tag);
writer.Write(nonce, 0, 12);
writer.Write(encrypted, 0, encrypted.Length);
writer.Write(tag, 0, 16);
}
}
}
private async void AddChatButton_OnClick(object sender, RoutedEventArgs e)
{
var dialog = new AddChatDialog();
string username = "", name = "";
byte delegateResult = 0; // 0 is running, 1 is done, 2 is canceled
Exception error = null;
await DialogHost.Show(dialog, "MainWindowDialogHost", async delegate(object sender1, DialogClosingEventArgs args)
{
if (!(bool)args.Parameter)
{
delegateResult = 2;
// check if the dialog is canceled
return;
}
username = dialog.IdTextBox.Text;
// check if the ID exists in database
var dbResult = await SharedStuff.Database.Table <DatabaseHelper.Users>().Where(user => user.Username == username)
.ToArrayAsync();
if (dbResult.Length == 0) // get the user's key from server
{
NameValueCollection queryString = HttpUtility.ParseQueryString(string.Empty);
queryString.Add("username", username);
string url = SharedStuff.CreateUrlWithQuery(
"https://" + Properties.Settings.Default.ServerAddress + "/users/getData", queryString);
string result;
try
{
using (WebClient wc = new WebClient()) // request other user's public key
result = await wc.DownloadStringTaskAsync(url);
}
catch (Exception ex)
{
error = new Exception("Cannot connect to server", ex);
delegateResult = 1;
return;
}
// check if the username exists
try
{
var data = JsonConvert.DeserializeObject <JsonTypes.UserDataStruct>(result);
if (data.PublicKey == "")
{
throw new Exception("User is not logged in.");
}
string key = Convert.ToBase64String(SharedStuff.Curve.calculateAgreement(
Convert.FromBase64String(_savedData.PrivateKey),
Convert.FromBase64String(data.PublicKey)));
await SharedStuff.Database.InsertAsync(
new DatabaseHelper.Users // save the key in database
{
Username = data.Username,
Name = data.Name,
Key = key,
});
name = data.Name;
}
catch (Exception)
{
var data = JsonConvert.DeserializeObject <JsonTypes.ServerStatus>(result);
error = new Exception("Server returned an error", new Exception(data.Message));
}
finally
{
delegateResult = 1;
}
}
});
// wait until the results are gathered
while (delegateResult == 0)
{
await Task.Delay(50);
}
if (delegateResult == 2)
{
return;
}
if (error != null)
{
var errDialog = new ErrorDialogSample
{
ErrorTitle = { Text = error.Message },
ErrorText = { Text = error.InnerException.Message }
};
await DialogHost.Show(errDialog, "MainWindowDialogHost");
return;
}
// check if messages list does not contain this user
if (MessagesList.All(x => x.Username != username))
{
MessagesList.Insert(0, new MainMessagesNotify
{
FullDate = DateTime.Now,
IsLastMessageForUser = false,
Message = "",
Name = name,
Username = username
});
}
// open the chat page
OpenWindowsList.Add(username, new ChatWindow(username));
OpenWindowsList[username].Show();
}
private async void WS_OnMessage(object sender, MessageEventArgs e)
{
// at first try to parse the message as Server status.
try
{
var status = JsonConvert.DeserializeObject <JsonTypes.MessageStatus>(e.Data);
if (status.Id != null) // a real message status
{
if (!status.Ok)
{
Console.WriteLine("Error on message " + status.Id + ": " + status.Message);
}
if (status.Message != "sent") // this is a file token update
{
SharedStuff.PendingMessages[status.Id].Token = status.Message;
// now start upload
SharedStuff.UploadFile(status.Id);
}
else
{
SharedStuff.PendingMessages[status.Id].Sent = status.Ok ? (byte)0 : (byte)2;
// Do not remove files from here; They are removed at "finally" block of SharedStuff.UploadFile
if (SharedStuff.PendingMessages[status.Id].Type != 1)
{
SharedStuff.PendingMessages.Remove(status.Id);
}
}
return;
}
if (status.Message != null && !status.Ok)
{
// TODO: HANDLE THIS SHIT
return;
}
}
catch (Exception)
{
// ignored : the type might be something else
}
// try ClientUpdateTypeStruct
await _mu.WaitAsync(); // get the data in order that server sends them
string nameSafe = "";
try
{
var msg = JsonConvert.DeserializeObject <JsonTypes.Updates>(e.Data);
var keyList = await SharedStuff.Database.Table <DatabaseHelper.Users>().Where(k => k.Username == msg.Payload.From)
.ToArrayAsync(); // get the key of the user
string key;
if (keyList.Length == 0) // Key agreement
{
var data = await SharedStuff.GetUserData(msg.Payload.From);
key = Convert.ToBase64String(SharedStuff.Curve.calculateAgreement(
Convert.FromBase64String(_savedData.PrivateKey),
Convert.FromBase64String(data.PublicKey)));
await SharedStuff.Database.InsertAsync(new DatabaseHelper.Users // save the key in database
{
Username = data.Username,
Name = data.Name,
Key = key,
});
nameSafe = data.Name;
}
else // get the key from database; There is only one row because Username is unique
{
key = keyList[0].Key;
}
string toShowOnMainMenu = "";
JsonTypes.FilePayload filePayload = new JsonTypes.FilePayload();
switch (msg.Type)
{
case 0: // Text message
// decrypt the message or assign the file token
try
{
string message = BouncyCastleHelper.AesGcmDecrypt(msg.Payload.Message, key);
await SharedStuff.Database.InsertAsync(new DatabaseHelper.Messages
{
Username = msg.Payload.From,
Type = msg.Type,
Date = msg.Payload.Date,
Payload = message
});
toShowOnMainMenu = message;
}
catch (Exception)
{
// TODO: RE-REQUEST public key
}
break;
case 1: // File message
filePayload = JsonConvert.DeserializeObject <JsonTypes.FilePayload>(msg.Payload.Message);
await SharedStuff.Database.RunInTransactionAsync(trans =>
{
trans.Insert(new DatabaseHelper.Messages
{
Username = msg.Payload.From,
Type = msg.Type,
Date = msg.Payload.Date,
Payload = filePayload.Token
});
trans.Insert(new DatabaseHelper.Files
{
Token = filePayload.Token,
Name = filePayload.FileName
});
});
toShowOnMainMenu = filePayload.FileName;
break;
}
// save the value
bool inserted = false, open = OpenWindowsList.ContainsKey(msg.Payload.From);
int index = -1;
try
{
index = MessagesList.IndexOf(MessagesList.First(x =>
x.Username == msg.Payload.From)); // get index of the UI
if (index == -1)
{
throw new Exception();
}
}
catch (Exception)
{
string name = nameSafe;
if (name == "")
{
name = (await SharedStuff.GetUserData(msg.Payload.From)).Name;
}
Application.Current.Dispatcher.Invoke(delegate
{
MessagesList.Insert(0, new MainMessagesNotify
{
FullDate = msg.Payload.Date,
Message = toShowOnMainMenu,
IsLastMessageForUser = false,
Name = name,
NewMessages = 1,
Username = msg.Payload.From
});
});
inserted = true;
}
if (index == -1)
{
return;
}
if (!open) // increase unread messages
{
await SharedStuff.Database.ExecuteAsync("UPDATE Users SET UnreadMessages = ? WHERE Username = ?",
MessagesList[index].NewMessages + 1, msg.Payload.From);
}
if (!inserted)
{
Application.Current.Dispatcher.Invoke(delegate
{
// Show the user the update
MessagesList.Move(index, 0);
MessagesList[0].FullDate = msg.Payload.Date;
MessagesList[0].Message = toShowOnMainMenu;
MessagesList[0].IsLastMessageForUser = false;
if (!open)
{
MessagesList[0].NewMessages++;
}
});
}
// update the open windows
if (open)
{
if (msg.Type == 0) // add text messages
{
OpenWindowsList[msg.Payload.From].AddMessageText(toShowOnMainMenu, msg.Payload.Date);
}
else if (msg.Type == 1) // add files
{
OpenWindowsList[msg.Payload.From].AddMessageFile(filePayload.Token, filePayload.FileName, msg.Payload.Date);
}
}
}
catch (Exception ex)
{
// TODO: HANDLE THIS SHIT
}
finally
{
_mu.Release();
}
}
