DeffiHellmen.java

//Client

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
import java.util.Scanner;
import java.util.concurrent.ThreadLocalRandom;

/*
  @author Jagyasi
 */
public class DH_CSCL4 {
    public static int BintoDec(int n){
        int result=0;
        int pow_val=0;
        while(n>0){
            int rem=n%10;
            result+=((int)Math.pow(2, pow_val))*rem ;
            pow_val++;
            n=n/10;
        }
        
        return result;
    }
    public static boolean isPrime(int n) {
        boolean flag = false;
        for (int i = 2; i < n; i++) {
            if (n % i == 0) {
                flag = false;
                break;
            } else {
                flag = true;
            }
        }
        return flag;
    }
       public static void main(String[] args) throws IOException {
           Socket s=new Socket("localhost",6646);
           Scanner in=new Scanner(System.in);
           DataInputStream din=new DataInputStream(s.getInputStream());
           DataOutputStream dout=new DataOutputStream(s.getOutputStream());
           int gen,prime;
           prime = ThreadLocalRandom.current().nextInt(2, 9 + 1);
           System.out.println("Prime"+prime);
        gen=ThreadLocalRandom.current().nextInt(1,prime);
           System.out.println("Generator"+gen);   
        if(isPrime(prime)){
               dout.writeInt(gen);
               dout.writeInt(prime);
               int a=ThreadLocalRandom.current().nextInt(2,8);
               int ApubKey=(int) ((Math.pow(gen, a)) % prime);
               System.out.println("efsdf   "+ApubKey);
               dout.writeInt(ApubKey);
               int BpubKey=din.readInt();
               System.out.println(BpubKey+"   frsfdsf");
               System.out.println("Enter numerical data...");
               int Adat=in.nextInt();
               int coded=Integer.parseInt(Integer.toBinaryString(Adat));
               int binApub=Integer.parseInt(Integer.toBinaryString(ApubKey));
               int packet=coded ^ binApub;
               dout.writeInt(BintoDec(packet));
               System.out.println("Sent...");
           }else {
            System.out.println("error....");
        }
           
    }
}


//Server

import java.util.concurrent.ThreadLocalRandom;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

/**
 *
 * @author Jagyasi
 */
public class DH_CSCL4_2 {
  public static void main(String[] args) throws IOException {
        ServerSocket ss = new ServerSocket(6646);
        Socket s = ss.accept();
        int gen = 0, prime = 0;
        int ApubKey;
        DataInputStream din = new DataInputStream(s.getInputStream());
        DataOutputStream dout = new DataOutputStream(s.getOutputStream());
        gen = din.readInt();
        prime = din.readInt();
        ApubKey=din.readInt();
        int b=ThreadLocalRandom.current().nextInt(2,8);
        int BpubKey=(int) (Math.pow(gen, b)%prime);
        dout.writeInt(BpubKey);
        int packet=din.readInt();
        int decoded=Integer.parseInt(Integer.toBinaryString(packet));
        int binBpub=Integer.parseInt(Integer.toBinaryString(BpubKey));
        int data=decoded^binBpub;
        
        System.out.println("Recieved....."+DH_CSCL4.BintoDec(data));

    }
}