Small application development

Question

Hi all,
Apologies if this kind of thing has been posted before. I was just wondering if anyone had any tips on how to achieve the following:
I would like to run a small platform independant application on the client side (in Swing maybe?) to accept a password. Once the correct password has been entered (don't worry about this at the mo), I need it to connect to a server side component (JSP / Servlet?) to authenticate the user. I am working on a new identification protocol unsing ZeroKnowledge thechniques.
So I need a small app to connect to a server side component, they will then send a few BigIntegers back and forth and if the right answer is recieved then the user is then allowed into a restricted area (such as email inbox, e-banking screen etc). Could anyone let me know if this is possible, I am a fairly competent Java programmer with bog standard J2SE but a bit weak on the web / networking technologies.
anti-spam alan underscore russell ' at' hotmail 'dot' com.

Answer 1

here's a simple client you can build off of:
import java.io.*;
import java.net.*;
public class Password {
     protected static final String SERVER_ADDRESS = "http://woogley.net/misc/Password/check.php";
     public Password() throws IOException {
          BufferedReader b = new BufferedReader(new InputStreamReader(System.in));
          boolean valid = false;
          while (!valid) {
               System.out.print("Enter the password: ");
               try {
                    valid = checkPass(b.readLine());
               catch (MalformedURLException e) {
                    valid = false;
          System.out.println("Password accepted.");
     protected boolean checkPass(String pass) throws MalformedURLException, IOException {
          URL u = new URL(SERVER_ADDRESS+"?pass="+pass);
          BufferedReader b = new BufferedReader(new InputStreamReader(u.openStream()));
          // the server code only returns one line, and
          // it'll either be "true" or "false"
          String s = b.readLine();
          if (s.equalsIgnoreCase("true")) {
               return true;
          return false;
     public static void main(String args[]) {
          try {
               new Password();
          catch (IOException e) {
               e.printStackTrace();
}the server-side code can be in any language you want, because to the application it's all HTTP in the end anyway. In this example I'll use PHP.. but you can use JSP if you want. Of course, this example isn't connecting to a password DB or decrypting or anything ;). The application just sends a GET variable (which is the password from the user) to the server script and the script will process with a few simple if statements:
<?php
$password = "dukeownsjames";
if (isset($_GET["pass"])) {
     // case-sensitive check
     if (strcmp($_GET["pass"],$password) == 0) {
          print "true";
     else {
          print "false";
else {
     print "false";
?>