Example #1
0
 // Close socket and IO streams, change appearance/functionality of some components
 private void closeAll() throws IOException {
   displayArea.append("\nConnection closing");
   output.close();
   input.close();
   connection.close();
   // We are no longer connected
   connection = null;
   // Change components
   serverField.setEditable(true);
   connectButton.setLabel("Connect to server above");
   enterField.setEnabled(false);
 }
Example #2
0
 public CipherChatClient() {
   super("Cipher Chat Client");
   // Establish keys for RSA cipher
   makeKeys();
   // Lay out the components and display the frame
   setLayout(new GridLayout(2, 1));
   top.setLayout(new GridLayout(3, 1));
   add(top);
   bottom.setLayout(new GridLayout(1, 1));
   add(bottom);
   connectButton.addActionListener(this);
   enterField.setEnabled(false);
   enterField.addActionListener(this);
   top.add(serverField);
   top.add(connectButton);
   top.add(enterField);
   bottom.add(displayArea);
   setSize(400, 300);
   show();
 }
Example #3
0
  public void actionPerformed(ActionEvent e) {
    Object source = e.getSource();
    // Client pressed enter in the message entry field-send it
    if (source == enterField) {
      // Get the message
      message = e.getActionCommand();
      try {
        // Encipher the message
        if (message.length() > plaintextBlockSize)
          message = message.substring(0, plaintextBlockSize);
        byte[] ciphertext =
            Ciphers.RSAEncipherWSalt(message.getBytes(), BigIntegerMath.THREE, recipModulus, sr);
        // Send to the server
        output.write(ciphertext);
        output.flush();
        // Display same message in client output area
        displayArea.append("\n" + message);
        enterField.setText("");
      } catch (IOException ioe) {
        displayArea.append("\nError writing message");
      }
    } else if (source == connectButton) {
      if (connection != null) { // Already connected-button press now means disconnect
        try {
          // Send final message of 0
          byte[] lastMsg = new byte[1];
          lastMsg[0] = 0;
          output.write(Ciphers.RSAEncipherWSalt(lastMsg, BigIntegerMath.THREE, recipModulus, sr));
          output.flush();
          // close connection and IO streams, change some components
          closeAll();
        } catch (IOException ioe) {
          displayArea.append("\nError closing connection");
        }
      } else { // Not connected-connect
        // Get name of server to connect to
        chatServer = serverField.getText();
        displayArea.setText("Attempting connection to " + chatServer);
        try {
          // Set up the socket
          connection = new Socket(chatServer, 55555);

          displayArea.append("\nConnected to: " + connection.getInetAddress().getHostName());

          // Set up the IO streams
          output = new DataOutputStream(connection.getOutputStream());
          output.flush();
          input = new DataInputStream(connection.getInputStream());

          // Exchange public keys with the server-send yours, get theirs
          exchangeKeys();

          // Change appearance/functionality of some components
          serverField.setEditable(false);
          connectButton.setLabel("Disconnect from server above");
          enterField.setEnabled(true);
          // Set up a thread to listen for the connection
          listener =
              new Thread(
                  new Runnable() {
                    public void run() {
                      go();
                    }
                  });
          listener.start();
        } catch (IOException ioe) {
          displayArea.append("\nError connecting to " + chatServer);
        }
      }
    }
  }