Diffie Hellman (Java)

Diffie Hellman: Receiver

import java.io.*;

import java.net.*;

import java.util.*;

public class DeffieHellmanRcv {

DatagramSocket theSocket = null;

int serverPort = 9999;

Scanner sc;

int y,g,p,r2;

DatagramPacket theRecievedPacket;

DatagramPacket theSendPacket;

InetAddress clientAddress;

int clientPort;

byte[] outBuffer;

byte[] inBuffer;

public DeffieHellmanRcv()

{

try {

// create the server UDP end point

theSocket = new DatagramSocket(serverPort);

System.out.println("Bob");

} catch (SocketException ExceSocket)

{

System.out.println("Socket creation error : "+ ExceSocket.getMessage());

}

}

public void keyGen()

{

sc=new Scanner(System.in);

System.out.print("Enter p=");

p=sc.nextInt();

System.out.print("Enter g=");

g=sc.nextInt();

System.out.print("Enter y=");

y=sc.nextInt();

r2= (int)(Math.pow(g,y)) % p;

//System.out.println("R2= "+r2);

}

public void send()

{

try

{

String message =r2+"";

System.out.println("Message Send:"+message);

//System.out.println("Message  sent: "+message);

outBuffer=message.getBytes();

System.out.println(message);

// send some data to the client

theSendPacket = new DatagramPacket(outBuffer, outBuffer.length, clientAddress, clientPort);

theSocket.send(theSendPacket);

}

catch (Exception e)

{

System.out.println("Error with client request : "+e);

}

// close the server socket

}

public void receive()

{

// create some space for the text to send and recieve data

outBuffer = new byte[500];

inBuffer = new byte[50];

try

{

// create a place for the client to send data too

theRecievedPacket = new DatagramPacket(inBuffer, inBuffer.length);

// wait for a client to request a connection

theSocket.receive(theRecievedPacket);

//System.out.println("Client connected");

// get the client details

clientAddress = theRecievedPacket.getAddress();

clientPort = theRecievedPacket.getPort();

String message = new String(theRecievedPacket.getData(),0,theRecievedPacket.getLength());

String sendData = message+"";

System.out.println("Message Recieved: "+message);

System.out.println(sendData);

outBuffer = sendData.getBytes();

int k2=(int)(Math.pow((Integer.parseInt(message)),y))%p;

System.out.println("\n\nk2= "+k2);

}

catch(Exception e)

{

System.out.println("E2"+e);

}

}

public static void main(String[] args)

{

DeffieHellmanRcv dr = new DeffieHellmanRcv();

dr.keyGen();

dr.receive();

dr.send();

}

}

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Diffie Hellman: Sender

import java.util.*;

import java.io.*;

import java.net.*;

public class DeffieHellmanSend

{

DatagramSocket theSocket = null;

int serverPort = 9999;

Scanner sc;

int x,g,p,r1;

DatagramPacket theSendPacket;

DatagramPacket theReceivedPacket;

InetAddress theServerAddress;

byte[] outBuffer;

byte[] inBuffer;

public DeffieHellmanSend()

{

try

{

theSocket = new DatagramSocket();

// but if you want to connect to your remote server, then alter the theServer address below

InetAddress theServer = InetAddress.getLocalHost();

theSocket.connect(theServer,serverPort);

System.out.println("Alice");

}

catch (SocketException ExceSocket)

{

System.out.println("Socket creation error  : "+ExceSocket.getMessage());

}

catch (UnknownHostException ExceHost)

{

System.out.println("Socket host unknown : "+ExceHost.getMessage());

}

}

public void keyGen()

{

sc=new Scanner(System.in);

System.out.print("Enter p=");

p=sc.nextInt();

System.out.print("Enter g=");

g=sc.nextInt();

System.out.print("Enter x=");

x=sc.nextInt();

r1= (int)(Math.pow(g,x)) % p;

System.out.println("R1= "+r1);

}

public void send()

{

// the place to store the sending and receiving data

inBuffer = new byte[500];

outBuffer = new byte[50];

try

{

String message=r1+"";

System.out.println("Message Sent:"+message);

outBuffer = message.getBytes();

// the server details

theServerAddress = theSocket.getLocalAddress();

// build up a packet to send to the server

theSendPacket = new DatagramPacket(outBuffer, outBuffer.length, theServerAddress, serverPort);

// send the data

theSocket.send(theSendPacket);

}

catch (IOException ExceIO)

{

System.out.println("Client getting data error : "+ExceIO.getMessage());

}

}

public void receive()

{

try

{

// get the servers response within this packet

theReceivedPacket = new DatagramPacket(inBuffer, inBuffer.length);

theSocket.receive(theReceivedPacket);

// the server response is...

String message = new String(theReceivedPacket.getData(),0,theReceivedPacket.getLength());

System.out.println("Message Recieved : "+message);

int temp=(int)(Math.pow((Integer.parseInt(message)),x));

temp=temp%p;

int k1=temp;

System.out.println("The temp is : "+k1);

//int k1=Integer.parseInt((Math.pow((Integer.parseInt(message)),x))%p);

//int k1=(int)(Math.pow((Integer.parseInt(message)),x))%p;

//System.out.println("Message REcieved: "+message);

//System.out.println("\n\nk1= "+k1);

}

catch(Exception e)

{

System.out.println("E1"+e);

}

}

public static void main(String[] args)

{

DeffieHellmanSend df = new DeffieHellmanSend();

df.keyGen();

df.send();

df.receive();

}

}

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