Java Security

Hi,

I'm new to encrypting data in JAVA, have spend a few days reading up about it
and trying several methods, the methods I have got to work have pretty weak encryption.

The code below is one I'd really like to get working properly but seem to be having trouble with

Any point in the right direction, or what I am doing wrong would be great help.

Cheers



This code - Works fine.

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
 
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
 
public class JEncryption
{    
	public static void main(String[] argv) {
 
		try{
 
		    KeyGenerator keygenerator = KeyGenerator.getInstance("DES");
		    SecretKey myDesKey = keygenerator.generateKey();
 
		    Cipher desCipher;
 
		    // Create the cipher 
		    desCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
 
		    // Initialize the cipher for encryption
		    desCipher.init(Cipher.ENCRYPT_MODE, myDesKey);
		   
		    System.out.println("MyDesKey - " + myDesKey);
		    //sensitive information
		    byte[] text = "This is your password".getBytes();
		    /*String jim = text.toString();*/
		    
		    System.out.println("Text [Byte Format] : " + text);
		    System.out.println("Conversion back from bytes - " + new String(text));	    
		    System.out.println("Text : " + new String(text));
 
		    
		    // Encrypt the text
		    byte[] textEncrypted = desCipher.doFinal(text);
 
		    System.out.println("Text Encryted : " + textEncrypted);
 
		    
		    // Initialize the same cipher for decryption
		    desCipher.init(Cipher.DECRYPT_MODE, myDesKey);

		    // Decrypt the text
		    byte[] textDecrypted = desCipher.doFinal(textEncrypted);
		    
 
		    System.out.println("Text Decryted : " + new String(textDecrypted));
 
		}catch(NoSuchAlgorithmException e){
			e.printStackTrace();
		}catch(NoSuchPaddingException e){
			e.printStackTrace();
		}catch(InvalidKeyException e){
			e.printStackTrace();
		}catch(IllegalBlockSizeException e){
			e.printStackTrace();
		}catch(BadPaddingException e){
			e.printStackTrace();
		} 
 
	}
}

The trouble is I want to write the encrypted message into a text file, then read it again
from another class.

So I tryed this below, tryed break down the key, then trying to rebuild the key (so I can
use it in another class once I get this right)

As you can see down the bottom, the first "Text Decryted : " Message will only show the
message it originally generate for this instance.

BUT the second one fails when it trys to Decrypt the code I have given it from class, the key
I've used with the 2nd one I have taken from another instance of running the program (the one
were I got the encrypted message to be decryted)

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
 
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
 
public class Enc
{    
	public static void main(String[] argv) {
 
		try{
 
		    KeyGenerator keygenerator = KeyGenerator.getInstance("DES");
		    SecretKey myDesKey = keygenerator.generateKey();
		    String jimbo = "¡uŠß†ÈÂ[";
		    byte[] james = jimbo.getBytes();

		    String algorithm = "DES";
		    SecretKey secretkey = new SecretKeySpec(james, algorithm);

		    System.out.println("getEncoded() : " + new String(james));	    
		    System.out.println("getAlgorithm() : " + algorithm);	
		    System.out.println("GET : " + secretkey);	 
		    System.out.println("                    /");
		    
		    Cipher desCipher;

		    // Create the cipher 
		    desCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
 
		    // Initialize the cipher for encryption
		    desCipher.init(Cipher.ENCRYPT_MODE, secretkey);
		   
		    System.out.println("MyDesKeyNEW = " + myDesKey);
		    //sensitive information
		    byte[] text = "[B@1b9ce4b".getBytes();
 
		    System.out.println("Text [Byte Format] : " + text);
		    System.out.println("Text : " + new String(text));
 
		    // Encrypt the text
		    byte[] textEncrypted = desCipher.doFinal(text);
 
		    System.out.println("Text Encryted : " + textEncrypted);
 
		    
		    // Initialize the same cipher for decryption
		    desCipher.init(Cipher.DECRYPT_MODE, secretkey);

		    // Decrypt the text
		    byte[] textDecrypted = desCipher.doFinal(textEncrypted);
		    
 
		    System.out.println("Text Decryted : " + new String(textDecrypted));
		    
		    // Decrypt the text
		    byte[] textDecrypted2 = desCipher.doFinal(text)
		    
 
		    System.out.println("Text Decryted : " + new String(textDecrypted2));
		}catch(NoSuchAlgorithmException e){
			e.printStackTrace();
		}catch(NoSuchPaddingException e){
			e.printStackTrace();
		}catch(InvalidKeyException e){
			e.printStackTrace();
		}catch(IllegalBlockSizeException e){
			e.printStackTrace();
		}catch(BadPaddingException e){
			e.printStackTrace();
		} 
 
	}
}

Do you think I'm going about this the right way, am I getting warm with it?

Is there a better way to be doing this?

Basically I want to take a string, encrypt it, save that to a text file, then decrypt it to read it
later on.

Any help would be fantastic,

Cheers, good day to you :-)