SAFE-CHAT
By
Thang Tran
Table of Contents
I.
What is Safe-Chat?
A.
Internet Insecurity
B.
Safe-Chat and Encryption
C.
Java
II.
Safe-Chat Development Team
III.
Requirements
IV.
Inputs and Outputs
V.
Project Timeline
VI.
How To Use Safe-Chat
VII.
Appendix A - SafeClient.java
VIII.
Appendix B – SafeServer.java
IX.
Appendix C – SafeCrypt.java
X.
References
XI.
What is Safe-Chat?
With many people using the Internet for communication, privacy becomes the top
concern for users. Either at home or work, your data can be intercepted. Many
companies are employing software to intercept emails and chat messages from their
own employees. Hackers can intercept data on transit with data sniffing tools. The
only way for secure and private communication is with encryption.
Safe-Chat provides a solution to today’s privacy problems. Safe-Chat is an
Internet chat program. Safe-Chat will encrypt a user’s message upon sending the
message, using the user’s encryption key. Upon receipt of an encrypted message,
Safe-Chat will decrypt the message for the recipient. Encryption before the message
can leave the user’s computer will ensure your data security. Only upon receipt of a
specified user can Safe-Chat decrypt the message. Safe-Chat uses Instant Message
style of communication and network tunneling. Users connect to another through a
point to point secure tunnel. To avoid third party ease dropping and encryption key
interception, point to point communication was employed.
Safe-Chat is built on Java technology to provide platform independence. Thus
allowing Safe-Chat to work on Windows computers, Unix computers, Macintosh
computers, Pocket PCs, Palms, cellular phones with a JVM, and many other devices.
Java will allow easy distribution of Safe-Chat to many platforms and users.
Safe-Chat Development Team
Thang Tran

Project Manager

Designer

Developer/Programmer

Tester

Distributor

Recorder
REQUIREMENTS

Internet Connection

Computer or Handheld device with a Java Virtual Machine
INPUTS

User Name

Plain Text Chat Message
OUTPUTS

Decrypted Plain Text Chat Message
TIMELINE
HOW TO USE SAFE-CHAT
Startup server side
Wait for a connection to establish
Setup Client Side
Once connected you may begin to chat securely
To terminate the chat session, type “/quit” in the chat window (any side can
terminate the session).
SAFECLIENT.JAVA
// Created by Thang Tran
// Program: SafeChat.java
// Description: This is the user interface client to Safe-Chat.
//
SafeClient impliments SafeCrypt for
//
encryption and decryption.
//
// Last Updated:
// Reason Updated:
import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class SafeClient extends JFrame
{
private JTextField enter;
private JTextArea display;
ObjectOutputStream output;
ObjectInputStream input;
String message = "";
public SafeClient()
{
super( "SafeClient" );
Container c = getContentPane();
enter = new JTextField();
enter.setEnabled( false );
enter.addActionListener(
new ActionListener()
{
public void actionPerformed( ActionEvent e )
{
sendData( e.getActionCommand() );
}
}
);
c.add( enter, BorderLayout.SOUTH );
display = new JTextArea();
c.add( new JScrollPane( display ),
BorderLayout.CENTER );
setSize( 300, 400 );
show();
}
public void runSafeClient()
{
Socket client;
try
{
// Create a Socket to make connection.
display.setText( "Attempting connection\n" );
client = new Socket(
InetAddress.getByName( "127.0.0.1" ), 5000 );
display.append( "Connected to: " +
client.getInetAddress().getHostName() );
// Get the input and output streams.
output = new ObjectOutputStream(
client.getOutputStream() );
output.flush();
input = new ObjectInputStream(
client.getInputStream() );
// Process connection.
enter.setEnabled( true );
do
{
try
{
message = (String) input.readObject();
// Decrypt the data stream
message = SafeCrypt.decrypt(message);
display.append( "\n" + message );
display.setCaretPosition(
display.getText().length() );
}
catch ( ClassNotFoundException cnfex )
{
display.append(
"\nUnknown object type received" );
}
} while ( !message.equals( "SERVER>>> /quit" ) );
// Step 4: Close connection.
display.append( "\nClosing connection.\n" );
output.close();
input.close();
client.close();
}
catch ( EOFException eof )
{
System.out.println( "Server terminated connection" );
}
catch ( IOException e )
{
e.printStackTrace();
}
}
private void sendData( String s )
{
String eBuffer = "";
String temp = "";
try
{
message = s;
// Encrypt the message
temp = "CLIENT>>> " + s;
eBuffer = SafeCrypt.encrypt(temp);
output.writeObject(eBuffer );
output.flush();
display.append( "\nCLIENT>>>" + s );
}
catch ( IOException cnfex )
{
display.append(
"\nError writing object" );
}
}
public static void main( String args[] )
{
SafeClient app = new SafeClient();
app.addWindowListener(
new WindowAdapter()
{
public void windowClosing( WindowEvent e )
{
System.exit( 0 );
}
}
);
app.runSafeClient();
}
}
BSAF
SAFESERVER.JAVA
// Created by Thang Tran
// Program: SafeSafeClient.java
// Description: This is the chat server to Safe-Chat.
//
SafeServer impliments SafeCrypt for
//
encryption and decryption.
//
// Last Updated:
// Reason Updated:
import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class SafeServer extends JFrame
{
private JTextField enter;
private JTextArea display;
ObjectOutputStream output;
ObjectInputStream input;
String message = "";
public SafeServer()
{
super( "SafeServer" );
Container c = getContentPane();
enter = new JTextField();
enter.setEnabled( false );
enter.addActionListener(
new ActionListener()
{
public void actionPerformed( ActionEvent e )
{
sendData( e.getActionCommand() );
}
}
);
c.add( enter, BorderLayout.SOUTH );
display = new JTextArea();
c.add( new JScrollPane( display ),
BorderLayout.CENTER );
setSize( 300, 400 );
show();
}
public void runSafeServer()
{
ServerSocket server;
Socket connection;
int counter = 1;
try
{
// Create a SafeServerSocket.
server = new ServerSocket( 5000, 100 );
while ( true )
{
// Wait for a connection.
display.setText( "Waiting for connection\n" );
connection = server.accept();
display.append( "Connection " + counter +
" received from: " +
connection.getInetAddress().getHostName() );
// Get input and output streams.
output = new ObjectOutputStream(
connection.getOutputStream() );
output.flush();
input = new ObjectInputStream(
connection.getInputStream() );
enter.setEnabled( true );
do
{
try
{
message = (String) input.readObject();
message = SafeCrypt.decrypt(message);
display.append( "\n" + message );
display.setCaretPosition(
display.getText().length() );
}
catch ( ClassNotFoundException cnfex ) {
display.append(
"\nUnknown object type received" );
}
} while ( !message.equals( "CLIENT>>> /quit" ) );
// Step 5: Close connection.
display.append( "\nUser terminated connection" );
enter.setEnabled( false );
output.close();
input.close();
connection.close();
++counter;
}
}
catch ( EOFException eof )
{
System.out.println( "Client terminated connection" );
}
catch ( IOException io )
{
io.printStackTrace();
}
}
private void sendData( String s )
{
String eBuffer = "";
String temp = "";
try
{
message = s;
// Encrypt the message
temp = "SERVER>>> " + s;
eBuffer = SafeCrypt.encrypt(temp);
output.writeObject(eBuffer );
output.flush();
display.append( "\nSERVER>>>" + s );
}
catch ( IOException cnfex )
{
display.append(
"\nError writing object" );
}
}
public static void main( String args[] )
{
SafeServer app = new SafeServer();
app.addWindowListener(
new WindowAdapter()
{
public void windowClosing( WindowEvent e )
{
System.exit( 0 );
}
}
);
app.runSafeServer();
}
}
SAFECRYPT.JAVA
// Created by Thang Tran
// Program: SafeCrypt.java
// Description: This program will encrypt and decrypt data.
//
// Last Updated:
// Reason Updated:
import java.util.*;
import java.lang.Object;
import java.lang.Math;
import java.lang.Integer;
import java.lang.*;
import java.io.*;
public class SafeCrypt {
static public char keyval = 'x';
public SafeCrypt() {
}
// Encrypt data
static public String encrypt(String inbuff)
{
char buffer[] = new char[inbuff.length()];
String edata;
// Convert over to an array of chars
buffer = inbuff.toCharArray();
for (int i = 0; i < inbuff.length(); i++)
{
buffer[i] = (char)(buffer[i]^keyval);
}
// Convert back to a string
edata = String.copyValueOf(buffer);
return edata;
}
// Decrypt data
static public String decrypt(String inbuff)
{
char buffer[] = new char[inbuff.length()];
String ddata;
// Convert over to an array of chars
buffer = inbuff.toCharArray();
for (int i = 0; i < inbuff.length(); i++)
{
buffer[i] = (char)(buffer[i]^keyval);
}
// Convert back to a string
ddata = String.copyValueOf(buffer);
return ddata;
}
}
REFERENCES
Deitel H.M and P.J. Deitel, “Java How To Program – Covers Java 2 Introducing
Swing,” Third Edition. Pentice Hall. 1999.