LanChan

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;

import javax.swing.*;
import javax.swing.border.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.io.IOException;
import java.net.*;
import java.security.*;
import java.security.spec.*;
import javax.xml.bind.DatatypeConverter;
import javax.crypto.*;
import javax.crypto.spec.*;

import java.awt.Color;
import javax.swing.SwingConstants;


public class LanChan extends JFrame {
    final int port = 1337;
    final int sendport = 1338;
    private MulticastSocket receive;
    private MulticastSocket send;
    private String nick, pass;
    private InetAddress group;
    private JPanel contentPane;
    private JTextField textField;
    private JLabel lblLanchanV;
    private JScrollPane scrollPane;
    private JTextArea textArea;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (Exception e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    LanChan frame = new LanChan();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }
    String encrypt(String str) {
        String encryptedValue = "";
        try {
            SecretKeyFactory f;
            f = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
            KeySpec ks = new PBEKeySpec(pass.toCharArray(), new byte[] { 0x7d, 0x60, 0x43, 0x5f, 0x02, (byte) 0xe9, (byte) 0xe0, (byte) 0xae }, 1024, 128);
            SecretKey s = f.generateSecret(ks);
            Key k = new SecretKeySpec(s.getEncoded(),"AES");

            Cipher c = Cipher.getInstance("AES");
            c.init(Cipher.ENCRYPT_MODE, k);
            byte[] encVal = c.doFinal(str.getBytes());
            encryptedValue = DatatypeConverter.printBase64Binary(encVal);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return encryptedValue;
    }
    String decrypt(String str) {
        String decryptedValue = "";
        try {
            SecretKeyFactory f;
            f = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
            KeySpec ks = new PBEKeySpec(pass.toCharArray(), new byte[] { 0x7d, 0x60, 0x43, 0x5f, 0x02, (byte) 0xe9, (byte) 0xe0, (byte) 0xae }, 1024, 128);
            SecretKey s = f.generateSecret(ks);
            Key k = new SecretKeySpec(s.getEncoded(),"AES");

            Cipher c = Cipher.getInstance("AES");
            c.init(Cipher.DECRYPT_MODE, k);
            byte[] encVal = new byte[0];
            try {
                encVal = c.doFinal(DatatypeConverter.parseBase64Binary(str));
            } catch(BadPaddingException e) {
                System.out.println("Packet from other channel received... Could not decrypt.");
            }
            decryptedValue = new String(encVal, "UTF-8");
        } catch (Exception e) {
            e.printStackTrace();
        }
        return decryptedValue;
    }
    void enter() {
        String input = textField.getText();
        textField.setText("");
        input = "<" + nick + "> " + input;
        input = encrypt(input);
        byte buffer[] = input.getBytes();
        DatagramPacket pack = new DatagramPacket(buffer, buffer.length, group, port);
        try {
            send.send(pack);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    /**
     * Create the frame.
     */
    public LanChan() {
        setTitle("LanChan");
        this.setMinimumSize(new Dimension(100, 100));

        nick = JOptionPane.showInputDialog(new JFrame("Nickname"), "Enter a username:");
        if (nick == null) {
            System.exit(1);
        }
        pass = JOptionPane.showInputDialog(new JFrame("Channel"), "Enter your channel:");
        if (pass == null) {
            System.exit(1);
        }

        String ip = "224.0.0.9";
        try {
            group = InetAddress.getByName(ip);
            receive = new MulticastSocket(port);
            send = new MulticastSocket(sendport);
            send.joinGroup(group);
            receive.joinGroup(group);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        new Thread(new Runnable() {
            @Override
            public void run() {
                while(true) {
                    byte[] buf = new byte[1024];
                    DatagramPacket p = new DatagramPacket(buf, buf.length);
                    try {
                        receive.receive(p);
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    String received = new String(p.getData());
                    received = decrypt(received);
                    JScrollBar vertical = scrollPane.getVerticalScrollBar();
                    vertical.setValue( vertical.getMaximum() );
                    textArea.append(received + "\n");
                }
            }
        }).start();




        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        contentPane.setLayout(new BorderLayout(0, 0));
        setContentPane(contentPane);

        textField = new JTextField();
        textField.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                enter();
            }
        });
        contentPane.add(textField, BorderLayout.SOUTH);
        textField.setColumns(10);

        lblLanchanV = new JLabel("v0.2");
        lblLanchanV.setInheritsPopupMenu(false);
        lblLanchanV.setHorizontalAlignment(SwingConstants.TRAILING);
        contentPane.add(lblLanchanV, BorderLayout.NORTH);

        scrollPane = new JScrollPane();
        scrollPane.setBorder(new BevelBorder(BevelBorder.LOWERED, null, null, null, null));
        scrollPane.setAutoscrolls(true);
        contentPane.add(scrollPane, BorderLayout.CENTER);

        textArea = new JTextArea();
        textArea.setLineWrap(true);
        textArea.setAutoscrolls(false);
        textArea.setEditable(false);
        textArea.setBorder(null);
        textArea.setBackground(Color.LIGHT_GRAY);
        scrollPane.setViewportView(textArea);
    }
}