Initial commit

9781565924024

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import java.io.*;

import java.net.*;

import java.security.*;

import java.util.Date;

import Protection;

public class DoubleClient {

  public void sendAuthentication(String user, String password,

      OutputStream outStream) throws IOException, NoSuchAlgorithmException {

    DataOutputStream out = new DataOutputStream(outStream);

    long t1 = (new Date()).getTime();

    double q1 = Math.random();

    byte[] protected1 = Protection.makeDigest(user, password, t1, q1);

    long t2 = (new Date()).getTime();

    double q2 = Math.random();

    byte[] protected2 = Protection.makeDigest(protected1, t2, q2);

    out.writeUTF(user);

    out.writeLong(t1);

    out.writeDouble(q1);

    out.writeLong(t2);

    out.writeDouble(q2);

    out.writeInt(protected2.length);

    out.write(protected2);

    out.flush();

  }

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

    String host = args[0];

    int port = 7999;

    String user = "Jonathan";

    String password = "buendia";

    Socket s = new Socket(host, port);

    DoubleClient client = new DoubleClient();

    client.sendAuthentication(user, password, s.getOutputStream());

    s.close();

  }

}

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import java.io.*;

import java.net.*;

import java.security.*;

import Protection;

public class DoubleServer {

  public boolean authenticate(InputStream inStream)

      throws IOException, NoSuchAlgorithmException {

    DataInputStream in = new DataInputStream(inStream);

    String user = in.readUTF();

    long t1 = in.readLong();

    double q1 = in.readDouble();

    long t2 = in.readLong();

    double q2 = in.readDouble();

    int length = in.readInt();

    byte[] protected2 = new byte[length];

    in.readFully(protected2);

    String password = lookupPassword(user);

    byte[] local1 = Protection.makeDigest(user, password, t1, q1);

    byte[] local2 = Protection.makeDigest(local1, t2, q2);

    return MessageDigest.isEqual(protected2, local2);

  }

  protected String lookupPassword(String user) { return "buendia"; }

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

    int port = 7999;

    ServerSocket s = new ServerSocket(port);

    Socket client = s.accept();

    DoubleServer server = new DoubleServer();

    if (server.authenticate(client.getInputStream()))

      System.out.println("Client logged in.");

    else

      System.out.println("Client failed to log in.");

    s.close();

  }

}

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