I am trying to implement password based encryption algorithm, but I get this exception:
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("DES");
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("DES/ECB/PKCS5Padding");
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("DES/ECB/PKCS5Padding");
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 = "Alpacas are awesome!".getBytes();
private PasswordCrypter[] passwordCrypters;
private byte[][] encryptedMessages;
@Before
public void setUp() {
passwordCrypters = new PasswordCrypter[] {
new PasswordCrypter("passwd"),
new PasswordCrypter("passwd"),
new PasswordCrypter("otherPasswd")
};
encryptedMessages = new byte[passwordCrypters.length][];
for (int i = 0; i < 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 < 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.
}
}
}
