I am trying to implement password based encryption algorithm, but I get this exception:

&gt; javax.crypto.BadPaddingException: Given final block not properly padded

What might be the problem?

Here is my code:

    public class PasswordCrypter {
    
    	private Key key;

    	public PasswordCrypter(String password)  {
			try{
			    KeyGenerator generator;
				generator = KeyGenerator.getInstance(&quot;DES&quot;);
				SecureRandom sec = new SecureRandom(password.getBytes());
				generator.init(sec);
				key = generator.generateKey();
			} catch (Exception e) {
    			e.printStackTrace();
    		}
    	}
    
    	
    	public byte[] encrypt(byte[] array) throws CrypterException {
    		try{
    			Cipher cipher = Cipher.getInstance(&quot;DES/ECB/PKCS5Padding&quot;);
    			cipher.init(Cipher.ENCRYPT_MODE, key);
    			 
			    return cipher.doFinal(array);
    		} catch (Exception e) {	
    			e.printStackTrace();
    		}
    		return null;
    	}
    
    	public byte[] decrypt(byte[] array) throws CrypterException{
        	try{
        		Cipher cipher = Cipher.getInstance(&quot;DES/ECB/PKCS5Padding&quot;);
        	    cipher.init(Cipher.DECRYPT_MODE, key);
        	    
        	    return cipher.doFinal(array);
        	} catch(Exception e ){
        		e.printStackTrace();
        	}
            return null;
    	}
    }
    
    
(The JUnit Test)
     
    public class PasswordCrypterTest {

    	private static final byte[] MESSAGE = &quot;Alpacas are awesome!&quot;.getBytes();
    	private PasswordCrypter[] passwordCrypters;
    	private byte[][] encryptedMessages;
    
    	@Before
    	public void setUp() {
    		passwordCrypters = new PasswordCrypter[] {
    			new PasswordCrypter(&quot;passwd&quot;),
    			new PasswordCrypter(&quot;passwd&quot;),
    			new PasswordCrypter(&quot;otherPasswd&quot;)
    		};
    
    		encryptedMessages = new byte[passwordCrypters.length][];
    		for (int i = 0; i &lt; passwordCrypters.length; i++) {
    			encryptedMessages[i] = passwordCrypters[i].encrypt(MESSAGE);
    		}
    	}
    
    	@Test
    	public void testEncrypt() {
    		for (byte[] encryptedMessage : encryptedMessages) {
    			assertFalse(Arrays.equals(MESSAGE, encryptedMessage));
    		}
    
    		assertFalse(Arrays.equals(encryptedMessages[0], encryptedMessages[2]));
    		assertFalse(Arrays.equals(encryptedMessages[1], encryptedMessages[2]));
    	}
    
    	@Test
    	public void testDecrypt() {
    		for (int i = 0; i &lt; passwordCrypters.length; i++) {
    			assertArrayEquals(MESSAGE, passwordCrypters[i].decrypt(encryptedMessages[i]));
    		}
    
    		assertArrayEquals(MESSAGE, passwordCrypters[0].decrypt(encryptedMessages[1]));
    		assertArrayEquals(MESSAGE, passwordCrypters[1].decrypt(encryptedMessages[0]));
    
    		try {
    			assertFalse(Arrays.equals(MESSAGE, passwordCrypters[0].decrypt(encryptedMessages[2])));
    		} catch (CrypterException e) {
    			// Anything goes as long as the above statement is not true.
    		}
    
    		try {
    			assertFalse(Arrays.equals(MESSAGE, passwordCrypters[2].decrypt(encryptedMessages[1])));
    		} catch (CrypterException e) {
    			// Anything goes as long as the above statement is not true.
    		}
    	}
    }




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Given final block not properly padded