Java/J2ME/Security

Password MIDlet

   <source lang="java">

/* Wireless Java 2nd edition Jonathan Knudsen Publisher: Apress ISBN: 1590590775

• /

import java.io.*; import java.util.Random; import javax.microedition.io.*; import javax.microedition.midlet.*; import javax.microedition.lcdui.*; import org.bouncycastle.crypto.Digest; import org.bouncycastle.crypto.digests.SHA1Digest; public class PasswordMIDlet extends MIDlet implements CommandListener, Runnable {

 private Display mDisplay;
 private Form mForm;
 private TextField mUserField, mPasswordField;
 private Random mRandom;
 
 public void startApp() { 
   mDisplay = Display.getDisplay(this);
   mRandom = new Random(System.currentTimeMillis());
   
   if (mForm == null) { 
     mForm = new Form("Login");
     mUserField = new TextField("Name", "jonathan", 32, 0);
     mPasswordField = new TextField("Password", "happy8", 32, 0);
     mForm.append(mUserField);
     mForm.append(mPasswordField);
     
     mForm.addCommand(new Command("Exit", Command.EXIT, 0));
     mForm.addCommand(new Command("Login", Command.SCREEN, 0));
     mForm.setCommandListener(this);
   } 
   mDisplay.setCurrent(mForm);
 } 
 
 public void commandAction(Command c, Displayable s) { 
   if (c.getCommandType() == Command.EXIT) notifyDestroyed();
   else {
     Form waitForm = new Form("Connecting...");
     mDisplay.setCurrent(waitForm);
     Thread t = new Thread(this);
     t.start();
   }
 } 
 public void run() { 
   // Gather the values we"ll need.
   long timestamp = System.currentTimeMillis();
   long randomNumber = mRandom.nextLong();
   String user = mUserField.getString();
   byte[] userBytes = user.getBytes();
   byte[] timestampBytes = getBytes(timestamp);
   byte[] randomBytes = getBytes(randomNumber);
   String password = mPasswordField.getString();
   byte[] passwordBytes = password.getBytes();
   
   // Create the message digest.
   Digest digest = new SHA1Digest();
   // Calculate the digest value.
   digest.update(userBytes, 0, userBytes.length);
   digest.update(timestampBytes, 0, timestampBytes.length);
   digest.update(randomBytes, 0, randomBytes.length);
   digest.update(passwordBytes, 0, passwordBytes.length);
   byte[] digestValue = new byte[digest.getDigestSize()];
   digest.doFinal(digestValue, 0);
   // Create the GET URL. The hex encoded message digest value is
   //   included as a parameter.
   URLBuilder ub = new URLBuilder(getAppProperty("PasswordMIDlet-URL"));
   ub.addParameter("user", user);
   ub.addParameter("timestamp",
       new String(HexCodec.bytesToHex(timestampBytes)));
   ub.addParameter("random",
       new String(HexCodec.bytesToHex(randomBytes)));
   ub.addParameter("digest",
       new String(HexCodec.bytesToHex(digestValue)));
   String url = ub.toString();
   try { 
     // Query the server and retrieve the response.
     HttpConnection hc = (HttpConnection)Connector.open(url);
     InputStream in = hc.openInputStream();
     
     int length = (int)hc.getLength();
     byte[] raw = new byte[length];
     in.read(raw);
     String response = new String(raw);
     Alert a = new Alert("Response", response, null, null);
     a.setTimeout(Alert.FOREVER);
     mDisplay.setCurrent(a, mForm);
     in.close();
     hc.close();
   } 
   catch (IOException ioe) { 
     Alert a = new Alert("Exception", ioe.toString(), null, null);
     a.setTimeout(Alert.FOREVER);
     mDisplay.setCurrent(a, mForm);
   } 
 } 
 
 private byte[] getBytes(long x) { 
   byte[] bytes = new byte[8];
   for (int i = 0; i < 8; i++)
     bytes[i] = (byte)(x >> ((7 - i) * 8));
   return bytes;
 } 
 
 public void pauseApp() { } 
 public void destroyApp(boolean unconditional) { } 

} class URLBuilder {

 private StringBuffer mBuffer;
 private boolean mHasParameters;
 
 public URLBuilder(String base) { 
   mBuffer = new StringBuffer(base);
   mHasParameters = false;
 } 
 
 public void addParameter(String name, String value) { 
   // Append a separator.
   if (mHasParameters == false) { 
     mBuffer.append("?");
     mHasParameters = true;
   } 
   else
     mBuffer.append("&");
   // Now tack on the name and value pair. These should
   //   really be URL encoded (see java.net.URLEncoder in
   //   J2SE) but this class appends the name and value
   //   as is, for simplicity. Names or values with spaces
   //   or other special characters will not work correctly.
   mBuffer.append(name);
   mBuffer.append("=");
   mBuffer.append(value);
 } 
 
 public String toString() { 
   return mBuffer.toString();
 } 

} class HexCodec {

 private static final char[] kDigits = { 
   "0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
   "a", "b", "c", "d", "e", "f"
 } ;
 
 public static char[] bytesToHex(byte[] raw) { 
   int length = raw.length;
   char[] hex = new char[length * 2];
   for (int i = 0; i < length; i++) { 
     int value = (raw[i] + 256) % 256;
     int highIndex = value >> 4;
     int lowIndex = value & 0x0f;
     hex[i * 2 + 0] = kDigits[highIndex];
     hex[i * 2 + 1] = kDigits[lowIndex];
   } 
   return hex;
 } 
 
 public static byte[] hexToBytes(char[] hex) { 
   int length = hex.length / 2;
   byte[] raw = new byte[length];
   for (int i = 0; i < length; i++) { 
     int high = Character.digit(hex[i * 2], 16);
     int low = Character.digit(hex[i * 2 + 1], 16);
     int value = (high << 4) | low;
     if (value > 127) value -= 256;
     raw[i] = (byte)value;
   } 
   return raw;
 } 
 
 public static byte[] hexToBytes(String hex) { 
   return hexToBytes(hex.toCharArray());
 } 

}

      </source>
   
  
 
  

Securing Your Applications

   <source lang="java">

/* Title: J2ME Games With MIDP2 Authors: Carol Hamer Publisher: Apress ISBN: 1590593820

• /

      </source>