Java Programming

Hello!

I have been playing around with the javax.crypto package, and testing encryption/decryption so I can implement it in my program.

After reading through

I noted that instead of fussing around with the DES Key "limit" (8 bytes), one can used "PBE" (Password Based Encryption) and supply a char array to create an encryption Key with.

However, unlike using DES encryption (which worked perfectly), PBE encryption gives me strange Exceptions which I cannot solve.

java.security.InvalidAlgorithmParameterException: Parameters missing

InvalidKeyException: requires PBE parameters

(stack traces at end, so as to include SSCCE code)

I am at a loss as to why these arise.
This is the code of my dummy program. What I've attempted to do to fix these errors follows that.

package SBX;

import java.io.*;
import java.security.*;
import java.security.spec.*;

import javax.swing.*;
import javax.crypto.*;
import javax.crypto.spec.*;

class Program {
    // Instance Variables
    String strToEncrypt = "This wants to be encrypted using Password Based Encryption";
    String decryptedResult = null;
    String algorithm = "PBEWithMD5AndDES";
    String password = "ProgramPassword";
    String filepath = "dummyFile.txt";

    // Main
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new Program().start();
            }
        });
    }

    // Constructors
    public Program() {}

    // Methods
    public void start() {
        encrypt();
        decrypt();
    }

    public void encrypt() {
        System.out.println("Encrypting: " + strToEncrypt);
        try {
            Cipher cipher = Cipher.getInstance(algorithm);
            SecretKey key = SecretKeyFactory.getInstance(algorithm).generateSecret(new PBEKeySpec(password.toCharArray()));
            cipher.init(Cipher.ENCRYPT_MODE, key);
            FileOutputStream fos = new FileOutputStream(filepath);
            CipherOutputStream cos = new CipherOutputStream(fos, cipher);
            ObjectOutputStream oos = new ObjectOutputStream(cos);
            oos.writeObject(strToEncrypt);
            oos.close();
            cos.close();
            fos.close();
        }
        catch (NoSuchAlgorithmException nsae) {
            System.out.println("No Such Algorithm!");
            nsae.printStackTrace();
        }
        catch (NoSuchPaddingException nspe) {
            System.out.println("No Such Padding!");
            nspe.printStackTrace();
        }
        catch (InvalidKeySpecException ikse) {
            System.out.println("Key Spec Was Invalid!");
            ikse.printStackTrace();
        }
        catch (InvalidKeyException ike) {
            System.out.println("Invalid Key!");
            ike.printStackTrace();
        }
        catch (IOException ioe) {
            System.out.println("IO Error!");
            ioe.printStackTrace();
        }
    }

    public void decrypt() {
        if (new File(filepath).exists()) {
            try {
                Cipher cipher = Cipher.getInstance(algorithm);
                SecretKey key = SecretKeyFactory.getInstance(algorithm).generateSecret(new PBEKeySpec(password.toCharArray()));
                cipher.init(Cipher.DECRYPT_MODE, key);
                FileInputStream fis = new FileInputStream(filepath);
                CipherInputStream cis = new CipherInputStream(fis, cipher);
                ObjectInputStream ois = new ObjectInputStream(cis);
                decryptedResult = (String) ois.readObject();
                ois.close();
                cis.close();
                fis.close();
                System.out.println("Decrypted: " + decryptedResult);
            }
            catch (NoSuchAlgorithmException nsae) {
                System.out.println("No Such Algorithm!");
                nsae.printStackTrace();
            }
            catch (NoSuchPaddingException nspe) {
                System.out.println("No Such Padding!");
                nspe.printStackTrace();
            }
            catch (InvalidKeySpecException ikse) {
                System.out.println("Key Spec Was Invalid!");
                ikse.printStackTrace();
            }
            catch (InvalidKeyException ike) {
                System.out.println("Invalid Key!");
                ike.printStackTrace();
            }
            catch (IOException ioe) {
                System.out.println("IO Error!");
                ioe.printStackTrace();
            } catch (ClassNotFoundException cnfe) {
                System.out.println("Could Not Class Cast!");
                cnfe.printStackTrace();
            }
        }
    }
}

Stack Traces

java.security.InvalidKeyException

java.security.InvalidKeyException: requires PBE parameters

	at com.sun.crypto.provider.PBEWithMD5AndDESCipher.engineInit(DashoA13*..)

	at javax.crypto.Cipher.a(DashoA13*..)

	at javax.crypto.Cipher.a(DashoA13*..)

	at javax.crypto.Cipher.init(DashoA13*..)

	at javax.crypto.Cipher.init(DashoA13*..)

	at SBX.Program.decrypt(Program.java:78)

	at SBX.Program.start(Program.java:34)

	at SBX.Program$1.run(Program.java:23)

	at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)

	at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)Invalid Key!



	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)

	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)

	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)

	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)

	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)

	at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)

java.security.InvalidAlgorithmParameterException

at com.sun.crypto.provider.SunJCE_ab.a(DashoA13*..)

	at com.sun.crypto.provider.PBEWithMD5AndDESCipher.engineInit(DashoA13*..)

	... 16 more

While encryption works beautifully, the decryption method encounters the above errors. At first I thought the java.security.InvalidKeyException was caused because, well, I was using an InvalidKey - so I tried using PBEKey in place of SecretKey, and classcasting the returned SecretKey from generateSecret into a PBEKey.

This caused classcast exceptions because somehow the compiler thought I was attempting to use the PBEKey within another package (forget the name), even though I was explicitly naming the path for the PBEKey every time it appeared in my code...

So then I thought maybe that PBE encryption doesn't work in the same way as DES encryption - ie, I can't follow the same routine with decryption as I did encryption... but that doesn't even make sense, how can I decrypt encrypted data with a Key that isn't exactly the same as the one used to encrypt it?

Any help would be appreciated!