Alexandra Buruciuc

Project TA

Class Main.java

import java.util.Random;

import java.io.*;

import java.io.*;

import java.net.*;

import java.util.*;

public class Main extends Thread {

static BigInteger p = new BigInteger(”0″), q = new BigInteger(”0″), n = new BigInteger(”0″);

static BigInteger t = new BigInteger(”0″), b = new BigInteger(”0″), s = new BigInteger(”0″);

static Random random = new Random();

static BigInteger ZERO = new BigInteger(”0″);

static BigInteger UNU = new BigInteger(”1″);

static BigInteger DOI = new BigInteger(”2″);

String Ja2, Ia, read;

SHA sha = new SHA();

BigInteger Ja,Ja_inv,sa;

private static ServerSocket serverSocket = null;

private Socket clientSocket = null;

public static final int PORT = 1987;

static void getParameters() {

while (n.bitLength() <= 160) {

while (p.compareTo(UNU) == -1 || q.compareTo(UNU) == -1) {

p = BigInteger.probablePrime(128, random);

q = BigInteger.probablePrime(128, random);

}

n = p.multiply(q);

}

t = p.subtract(UNU).multiply(q.subtract(UNU));

while (b.compareTo(new BigInteger(”3″)) == -1 || b.gcd(t).compareTo(UNU) != 0 || b.compareTo(t.subtract(UNU)) == 1) {

b = BigInteger.probablePrime(t.subtract(UNU).bitLength(), random);

}

s = b.modInverse(t);

}

static void afisareParam() {

System.out.println(”p:” + p);

System.out.println(”q:” + q);

System.out.println(”n:” + n + ” lungime:” + n.bitLength());

System.out.println(”t:” + t);

System.out.println(”b:” + b);

System.out.println(”gcd(b,t)=” + b.gcd(t));

System.out.println(”s:” + s);

System.out.println(”b*s=” + b.multiply(s).mod(t) + ” mod t”);

}

public void run() {

//Executa solicitarea clientului

try {

BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));

PrintWriter out = new PrintWriter(clientSocket.getOutputStream());

read = in.readLine();

System.out.println(read);

out.write(”Hello from TA”+”\n”);

out.flush();

Ia = in.readLine();

System.out.println(”Ia: ” + Ia);

Ja2 = sha.SHA2(Ia);

System.out.println(”Ja string: ” + Ja2);

Ja = sha.SHA1(Ia);

System.out.println(”Ja BigInteger: ” + Ja + ” lungime: “+ Ja.bitLength());

Ja_inv=Ja.modInverse(n);

System.out.println(”Ja_inv: ” + Ja_inv);

sa=Ja_inv.modPow(s, n);

System.out.println(”s_a: ” + sa);

out.write(n+”\n”);

out.write(b+”\n”);

out.write(sa+”\n”);

out.flush();

} catch (Exception e) {

System.err.println(e);

} finally {

// Inchid socketul deschis pentru clientul curent

try {

clientSocket.close();

} catch (IOException e) {

System.err.println(”Socketul nu poate fi inchis \n” + e);

}

}

}

public Main() throws IOException {

getParameters();

afisareParam();

// while (true) {

serverSocket = new ServerSocket(PORT);

System.out.println(” TA -> initiated!”);

try {

//Asteapta un client

clientSocket = serverSocket.accept();

//Executa solicitarea clientului intr-un fir de executie

new Thread(this).start();

} finally {

serverSocket.close();

System.out.println(” TA -> finished!”);

}

// }

}

public static void main(String[] args) throws IOException {

Main m = new Main();

}

}

Class SHA.java

package TA;

import java.io.UnsupportedEncodingException;

import java.math.BigInteger;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

public class SHA {

private static String convertToHex(byte[] data) {

StringBuffer buf = new StringBuffer();

for (int i = 0; i < data.length; i++) {

int halfbyte = (data[i] >>> 4) & 0×0F;

int two_halfs = 0;

do {

if ((0 <= halfbyte) && (halfbyte <= 9)) {

buf.append((char) (’0′ + halfbyte));

} else {

buf.append((char) (’a’ + (halfbyte – 10)));

}

halfbyte = data[i] & 0×0F;

} while (two_halfs++ < 1);

}

return buf.toString();

}

public static BigInteger convertToBigInteger(byte[] input) {

BigInteger r = new BigInteger(input);

return r;

}

public static BigInteger SHA1(String text)

throws NoSuchAlgorithmException, UnsupportedEncodingException {

MessageDigest md;

md = MessageDigest.getInstance(”SHA-1″);

byte[] sha1hash = new byte[40];

md.update(text.getBytes(”iso-8859-1″), 0, text.length());

sha1hash = md.digest();

return convertToBigInteger(sha1hash);

}

public static String SHA2(String text)

throws NoSuchAlgorithmException, UnsupportedEncodingException {

MessageDigest md;

md = MessageDigest.getInstance(”SHA-1″);

byte[] sha1hash = new byte[40];

md.update(text.getBytes(”iso-8859-1″), 0, text.length());

sha1hash = md.digest();

return convertToHex(sha1hash);

}

}

Project A

Class Main.java

package A;

import java.net.*;

import java.io.*;

import java.math.BigInteger;

import java.util.Random;

public class Main {

String identitate = “Eu sunt A”,raspuns=”accept”;

String Ja2, sa2, n2, b2,r2;

BigInteger Ja, sa, n, b, k = new BigInteger(”0″),alfa= new BigInteger(”0″),r,y=new BigInteger(”0″);

byte[] aux;

SHA sha = new SHA();

Random random = new Random();

int NR_VERIFICARI,incercari=0;

static BigInteger ZERO = new BigInteger(”0″);

static BigInteger UNU = new BigInteger(”1″);

static BigInteger DOI = new BigInteger(”2″);

public void Communication() throws Exception {

System.out.println(” A -> initiated!”);

String adresaServer = “127.0.0.1″;

int PORT = 1987;

Socket clientSocket = null;

PrintWriter out = null;

BufferedReader in = null;

try {

clientSocket = new Socket(adresaServer, PORT);

out = new PrintWriter(clientSocket.getOutputStream(), true);

in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));

out.write(”Hello from A” + “\n”);

out.write(identitate + “\n”);

out.flush();

String read = in.readLine();

System.out.println(read);

Ja2 = sha.SHA2(identitate);

System.out.println(”Ja string: ” + Ja2);

Ja = sha.SHA1(identitate);

System.out.println(”Ja BigInteger: ” + Ja);

n2 = in.readLine();

n = new BigInteger(n2, 10);

System.out.println(”n: ” + n);

b2 = in.readLine();

b = new BigInteger(b2, 10);

System.out.println(”b: ” + b);

sa2 = in.readLine();

sa = new BigInteger(sa2, 10);

System.out.println(”sa: ” + sa);

} catch (Exception e) {

System.err.println(e);

System.exit(1);

} finally {

if (out != null) {

out.close();

}

if (in != null) {

in.close();

}

if (clientSocket != null) {

clientSocket.close();

}

}

clientSocket = null;

out = null;

in = null;

PORT = 1988;

try {

clientSocket = new Socket(adresaServer, PORT);

out = new PrintWriter(clientSocket.getOutputStream(), true);

in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));

String read = in.readLine();

System.out.println(read);

NR_VERIFICARI=Integer.parseInt(in.readLine());

System.out.println(”Nr verificari: “+ NR_VERIFICARI);

out.write(”Hello from A” + “\n”);

out.flush();

while(raspuns.compareTo(”accept”)==0 && incercari<NR_VERIFICARI)

{

incercari++;

out.write(identitate + “\n”);

out.flush();

int lungime = n.bitLength();

int random_lungime = 0;

while (k.compareTo(UNU) == -1 || k.compareTo(n) >= 0) {

while (random_lungime == 0) {

random_lungime = random.nextInt(lungime);

}

k = BigInteger.probablePrime(random_lungime, random);

}

System.out.println(”k: ” + k);

alfa=k.modPow(b, n);

System.out.println(”alfa: ” + alfa);

out.write(n+”\n”);

out.write(b+”\n”);

out.write(alfa+”\n”);

out.flush();

r2 = in.readLine();

r = new BigInteger(r2, 10);

System.out.println(”r: ” + r);

y=sa.modPow(r, n).multiply(k).mod(n);

System.out.println(”y: ” + y);

out.write(y+”\n”);

out.flush();

raspuns=in.readLine();

System.out.println(”raspuns “+raspuns);

}

} catch (Exception e) {

System.err.println(e);

System.exit(1);

} finally {

if (out != null) {

out.close();

}

if (in != null) {

in.close();

}

if (clientSocket != null) {

clientSocket.close();

}

}

System.out.println(” A -> finished!”);

}

public static void main(String[] args) throws Exception {

Main m = new Main();

m.Communication();

}

}

Class SHA – la fel ca cea de la TA

Project B

Class Main.java

package B;

import java.math.BigInteger;
import java.util.Random;
import java.io.*;
import java.io.*;
import java.net.*;
import java.util.*;

public class Main extends Thread {

static Random random = new Random();
static SHA sha = new SHA();
static BigInteger ZERO = new BigInteger(”0″);
static BigInteger UNU = new BigInteger(”1″);
static BigInteger DOI = new BigInteger(”2″);
BigInteger verificare = new BigInteger(”0″), Ja, alfa = new BigInteger(”0″), n, b, r = new BigInteger(”0″), y = new BigInteger(”0″);
String Ia, read, alfa2, n2, b2, y2, Ja2;
private static ServerSocket serverSocket = null;
private Socket clientSocket = null;
public static final int PORT = 1988;
int NR_VERIFICARI = 4;
boolean respins = false;

public void run() {
int accepta = 0;
//Executa solicitarea clientului
try {
BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
PrintWriter out = new PrintWriter(clientSocket.getOutputStream());

out.write(”Hello from B” + “\n”);
out.write(NR_VERIFICARI+”\n”);
out.flush();

read = in.readLine();
System.out.println(read);

while (accepta < NR_VERIFICARI && respins == false) {
Ia = in.readLine();
System.out.println(”Ia: ” + Ia);

n2 = in.readLine();
n = new BigInteger(n2, 10);
System.out.println(”n: ” + n);

b2 = in.readLine();
b = new BigInteger(b2, 10);
System.out.println(”b: ” + b);

alfa2 = in.readLine();
alfa = new BigInteger(alfa2, 10);
System.out.println(”alfa: ” + alfa);

int lungime = n.bitLength();
int random_lungime = 0;
while (r.compareTo(UNU) == -1 || r.compareTo(b) > 0) {
while (random_lungime == 0) {
random_lungime = random.nextInt(lungime);
}
r = BigInteger.probablePrime(random_lungime, random);
}
System.out.println(”r: ” + r);

out.write(r + “\n”);
out.flush();

y2 = in.readLine();
y = new BigInteger(y2, 10);
System.out.println(”y: ” + y);

Ja2 = sha.SHA2(Ia);
System.out.println(”Ja: ” + Ja2);
Ja = sha.SHA1(Ia);
System.out.println(”Ja: ” + Ja);

verificare = Ja.modPow(r, n).multiply(y.modPow(b, n)).mod(n);
System.out.println(”Verificare: ” + verificare);

if (verificare.compareTo(alfa) == 0) {
accepta++;
System.out.println(”Accept !!! “);
out.write(”accept” + “\n”);
out.flush();
} else {
respins = true;
out.write(”respins” + “\n”);
out.flush();
System.out.println(”Reject !!! “);
}
}

if(accepta==NR_VERIFICARI)
{
System.out.println(”IDENTIFICARE REUSITA !!! “);
}
else
{
System.out.println(”IDENTIFICARE ESUATA !!! “);
}

} catch (Exception e) {
System.err.println(e);
} finally {
// Inchid socketul deschis pentru clientul curent
try {
clientSocket.close();
} catch (IOException e) {
System.err.println(”Socketul nu poate fi inchis \n” + e);
}
}
}

public Main() throws IOException {

//  while (true) {
serverSocket = new ServerSocket(PORT);

try {
//Asteapta un client
clientSocket = serverSocket.accept();
System.out.println(” B -> initiated!”);
//Executa solicitarea clientului intr-un fir de executie
new Thread(this).start();

} finally {
serverSocket.close();
System.out.println(” B -> finished!”);
}
// }

}

public static void main(String[] args) throws IOException {
Main m = new Main();
}
}
Class SHA - la fel ca la TA