mGz developer blog

package list1;
 
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
 
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 CW1 {
	public static byte[] getKey(int bytes) throws NoSuchAlgorithmException{
		KeyGenerator kGen = KeyGenerator.getInstance("DES");
		byte[] key = new byte[bytes];
		int i = 0;
		while(i < bytes){
			kGen.init(56);		
			SecretKey sKey = kGen.generateKey();
			byte[] rawKey = sKey.getEncoded();
			for(int j = 0; (j < rawKey.length)&(j+i < key.length) ; j++){
				key[j+i] = rawKey[j];
			}
			i = i + 7;
		}
		return key;
	}
 
	public static void main(String[] args) throws NoSuchAlgorithmException,
			NoSuchPaddingException, InvalidKeyException,
			IllegalBlockSizeException, BadPaddingException {
		/*
		 * długość wiadomość musi być podzielna przez 8
		 * żeby można było użyć NoPadding
		 */
		byte[] input = "WiadomoscDoZakodowania!!".getBytes();
		byte[] encrypted = null;
		byte[] decrypted = null;
 
		KeyGenerator kGen = KeyGenerator.getInstance("DES");
		SecretKey sKey = kGen.generateKey();
		byte[] keyBytes = sKey.getEncoded();
 
		Cipher cipher = Cipher.getInstance("DES/ECB/NoPadding");
 
		cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(keyBytes, "DES"));
		encrypted = cipher.doFinal(input);
 
		cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(keyBytes, "DES"));
		decrypted = cipher.doFinal(encrypted);
 
		print(input);
		print(encrypted);
		print(decrypted);
 
		System.out.println(Arrays.equals(input, decrypted));
	}
 
	public static void print(byte[] b) {
		System.out.println(new String(b));
		System.out.println("Length: " + b.length * 8);
		System.out.println("---------------");
	}
}

package main;
 
import java.security.NoSuchAlgorithmException;
 
import javax.crypto.Cipher;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;
 
public class Main {
	public static void main(String args[])
	{
 
		try {
 
		byte[] teskJawny = "Teskt jawny".getBytes();
 
		byte[] klucz =     "klucz".getBytes();
 
		System.out.println(XORCoderToString(XORcoder(teskJawny, klucz), klucz));
 
 
 
 
		byte[] keyBytes = null;
		SecretKeySpec key = new SecretKeySpec(keyBytes,"DES");
 
 
			Cipher szyfr = Cipher.getInstance("DES/ECB/SKCS5Padding");
 
 
 
 
		} catch (NoSuchAlgorithmException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (NoSuchPaddingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
 
 
	}
 
	/**
	 * Metoda wykonuje operacje XOR na podanych tablicach i zwraca wynik w nowej tablicy 
	 * @param msg tablica wiadomosci
	 * @param key tablica klucza
	 * @return tablica po operacji XOR
	 */
	public static byte[] XORcoder(byte[] msg, byte[] key) {
 
	byte[] ret = new byte[msg.length];
 
 
		for(int i=0; i<msg.length; i++)
			ret[i] = (byte) (msg[i]^key[i%key.length]);
 
		return ret;
 
	}
 
	/**
	 * Metoda wykonuje operacje XOR i zwraca wynik w postaci tekstu
	 * @param msg testk do operacji XOR
	 * @param key klucza do operacji XOR
	 * @return teskt otrzymany po operacji XOR
	 */
	public static String XORCoderToString(byte[] msg, byte[] key)
	{
		StringBuilder sb= new StringBuilder();
		byte[] tmp =  XORcoder(msg, key);
		for (byte b : tmp) {
			sb.append((char)b);
		}
 
		return sb.toString();
	}
}