Disabling the keys with my Java Program

I have a program that extends a JWindow. I would like to make this program my destop, as in disabling all function keys on the keyboard including ctrl+alt+del and others like that.
Some Internet cafe shops use this technique to restrict unauthorised customers from accessing their PCs.
If anyone knows how, please help.
Thanks in advance.

Keys that are listened to by the Window Environment cannot be intercepted with Java alone. This include Ctrl-Alt-Del, as well as Alt-Tab for MS Windows. You would need JNI to do this.
If you use Linux, you could do it in pure Java, with one exception. Ctrl-Alt-Del would terminate X, and bring you to a console login. You may be able to disable that somewhere in the X configuration. This would prevent anyone from getting access to the system, unless they have the login for it. To do this you would need to setup X so it starts without the Gnome/KDE Desktop Manager, and runs your full screen Java app instead.

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Sending the key with Socket

Hello!
I have made an application that encrypts a byte[], sends it to a server.
And after that i am trying to decrypt it. But that gives me problem.
The exception i get is:
BadPaddingException: javax.crypto.BadPaddingException: Given final block not properly padded.
This is my code.
The client
import java.net.*;
import java.io.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.security.*;
import java.security.spec.*;
import java.util.*;
class Client
public static void main(String a[])
    Socket socket = null;
    try
      // Create Key
      KeyGenerator kg = KeyGenerator.getInstance("DES");
      SecretKey secretKey = kg.generateKey();
      // Create Cipher
      Cipher desCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
      desCipher.init(Cipher.ENCRYPT_MODE, secretKey);
      socket = new Socket("localhost", 3000);
      DataOutputStream dataOutputStream = new DataOutputStream(socket.getOutputStream());
      ObjectOutputStream out = new ObjectOutputStream(socket.getOutputStream());
      File file = new File("Mattias.jpg");
      FileInputStream fileInputStream = new FileInputStream(file);
      byte[] bytes = new byte[(int)file.length()];
      fileInputStream.read(bytes);
      fileInputStream.close();
      byte[] encryptedBytes = new byte[(int)file.length()];
      encryptedBytes = desCipher.doFinal(bytes);
      out.writeInt((int)file.length());
      out.writeObject((Object)secretKey);
      dataOutputStream.write(encryptedBytes);
      out.flush();
      dataOutputStream.flush();
      out.close();
      dataOutputStream.close();
    catch(IOException e)
      e.printStackTrace();
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      System.err.println("Padding problem: " + e);
    catch (NoSuchAlgorithmException e)
      System.err.println("Invalid algorithm: " + e);
    catch (InvalidKeyException e)
      System.err.println("Invalid key: " + e);
    catch (IllegalBlockSizeException e)
      System.err.println("IllegalBlockSizeException: " + e);
    catch (BadPaddingException e)
      System.err.println("BadPaddingException: " + e);
    finally
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        socket.close();
      catch(IOException e)
        e.printStackTrace();
The server
import java.net.*;
import java.io.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.security.*;
import java.security.spec.*;
import java.util.*;
class Server
public static void main(String a[]) throws IOException
    new Server().listen(3000);
public void listen(int port) throws IOException
    ServerSocket serverSocket = new ServerSocket(port);
    new SocketHandler(serverSocket.accept()).start();
class SocketHandler extends Thread
    Socket socket = null;
    SocketHandler(Socket socket)
      this.socket = socket;
    public void run()
      try
        SecretKey secretKey = null;
        File file = new File("file.jpg");
        OutputStream fileOutputStream = new FileOutputStream(file);
        BufferedInputStream bufferedInputStream = new BufferedInputStream(socket.getInputStream());
        ObjectInputStream in = new ObjectInputStream(socket.getInputStream());
        int fileSize = in.readInt();
        byte[] encryptedBytes = new byte[fileSize * 8];
        byte[] bytes = new byte[fileSize];
        secretKey = (SecretKey)in.readObject();
        // Create Cipher
        Cipher desCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
        desCipher.init(Cipher.DECRYPT_MODE, secretKey);
        int i = -1;
        while (true)
          i = bufferedInputStream.read(encryptedBytes, 0, encryptedBytes.length);
          bytes = desCipher.doFinal(encryptedBytes);
          if (i == -1)
            break;
          fileOutputStream.write(bytes, 0, i);
        bufferedInputStream.close();
        fileOutputStream.flush();
        fileOutputStream.close();
      catch (IOException ioe)
        ioe.printStackTrace();
        catch(ClassNotFoundException cnfe)
        cnfe.printStackTrace();
      catch (NoSuchPaddingException e)
        System.err.println("Padding problem: " + e);
      catch (NoSuchAlgorithmException e)
        System.err.println("Invalid algorithm: " + e);
      catch (InvalidKeyException e)
        System.err.println("Invalid key: " + e);
      catch (IllegalBlockSizeException e)
        System.err.println("IllegalBlockSizeException: " + e);
      catch (BadPaddingException e)
        System.err.println("BadPaddingException: " + e);
      finally
        try
          socket.close();
        catch (IOException ioe)
          ioe.printStackTrace();
}What am i doing wrong? How should i solve it?

This looks suspect -DataOutputStream dataOutputStream = new DataOutputStream(socket.getOutputStream());
      ObjectOutputStream out = new ObjectOutputStream(socket.getOutputStream());It is normally a bad idea to attach a single OutputStream to 2 or more 'filter' streams.
You could always sent the data as an object i.e.out.writeObject(encryptedBytes);Also, you make the assumption that the encrypted length is the same as the file length. With PKCS5Padding this is never the case since it pads with 1 to 8 bytes to make up to the block size. This is probably the cause of the BadPaddingException. If you send the encrpted data over as an object then you don't need to send the length.
Your stream uses in the client and server differ. You have no DataInputStream in the server to match the DataOuputStream in the client. To be safe, stick to Object streams or Data streams but don't mix.
P.S. Isn't sending the key with the cipher text a litte insecure!!!

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I changed the about:config to make the rotate gesture move between tabs, and it worked great for well over a year. Now it behaves erratically as described here:
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Just set the browser.gesture.twist.threshold to something around 15-25.

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Hello -
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Bex Hierarchy showing just the key with Attributes ????

Hierarchy showing just the key with Attributes ???? I want the Text without attribute!
I had created a Hierarchy manually on 0companycode characteristic, but I have some problems.
1 u2013 Itu2019s showing just the KEY (On query Design is marked to show the text , and Iu2019m on the proper language).
2 u2013 On the last lever that is the company code, is showing the key with all attributes like this.
-> CONTRY_BR
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Regards
Edited by: Marcus Coufal on Mar 4, 2011 1:53 PM

On the caracteristic -> attribute put 0 on "Order For"

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Thanks

Hi,
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Liek if u want to get notified when a mouse is clicked, then u need to add The MouseListener to the component which u want to be monitored.
Say
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Hi all
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i need sample code on how to edit the existing data in the XML file?
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[points will be always rewardable]

hi
u need a parser or validate the xml file for to read the xml file from java coding u need for this
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http://www.alphaworks.ibm.com/tech/xml4j
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http://www.java-tips.org/java-se-tips/javax.xml.parsers/how-to-read-xml-file-in-java.html
http://www.developertutorials.com/tutorials/java/read-xml-file-in-java-050611/page1.html
http://www.xml-training-guide.com/e-xml44.html
let me know u need any other info
bvr

Need Help with a JAVA programming assignment

How do I write a JAVA program that could be used as the start of an MS-DOS/Windows simulation of the IEEE 802.3 protocol? I am to only code the parts necessary to build the 802.3 frame. For the initial implementation, the Checksum function need not be a CRC function, and the Destination and Source addresses wil be in input, stored, and output, and in dotted-decimal format.
I need:
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Thanks...........TK

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good morning | afternoon | evening my friends,
I can download applet with JCop now, but I have to do it with my program,can someone tell me how to do it,especially the steps.
Allen,

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Eve

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Hey again!
I missed out some information in last posting.. here is the full description
I have just installed 1.5.0_06 and have set paths and what otherwise is necessary to run the java programs. I was testing the install and run a standard HelloWorld.java program
I got the following error:
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public HelloWorld()
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public static void main(String[] args)
HelloWorld hw = new HelloWorld();
I have checked that the path is correct too..
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java -cp . HelloWorld
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http://java.sun.com/j2se/1.5.0/docs/tooldocs/index.html#general
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FindPollApp.java:9: illegal start of type
if(dir.isDirectory())
^
FindPollApp.java:18: <identifier> expected
^
2 errors
Thanks.

I'm a complete novice with Java. I want to write a
Java program to run on Windows 2000 servers to write
a list of certain files in a directory into a *.txt
file. I hope to add complexity once I have this
basic part working. Here's the code I have so far:
//this Java application finds poll* files
public class FindPollApp
//Create File Object
File dir = new File("d:/jda/windss/poll");
//List directory
if(dir.isDirectory())
String[] dirContents = dir.list();
for (int i=0; i < dirContents.length; i++)
System.out.println(dirContents);
//Iterate through files
I get the following errors:
C:\JAVA>javac FindPollApp.java
FindPollApp.java:9: illegal start of type
if(dir.isDirectory())
^
FindPollApp.java:18: <identifier> expected
^
2 errors
Thanks.
You need to create a method and insert your if statement in there

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Hi,
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Disabling the keys with my Java Program

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