TLgwCiNQ

1public class Test {
2
3    public static String test = "Hallo, ich bin eine Test Nachricht!";
4
5    public static void main( String[] args ) throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException, InvalidAlgorithmParameterException {
6        byte[] initVector = new byte[16];
7        new Random().nextBytes( initVector );
8        IvParameterSpec ivParameterSpec = new IvParameterSpec( initVector );
9        KeyGenerator keyGenerator = KeyGenerator.getInstance( "AES" );
10        SecretKey key = keyGenerator.generateKey();
11        Cipher cipher = Cipher.getInstance( "AES/CBC/PKCS5PADDING" );
12
13        cipher.init( Cipher.ENCRYPT_MODE, key, ivParameterSpec );
14        byte[] toEncrypt = test.getBytes();
15        byte[] encrypted = new byte[0];
16        for ( int i = 0; i < toEncrypt.length; i++ ) {
17            byte b = toEncrypt[i];
18            byte[] result = cipher.update( new byte[]{ b } );
19            encrypted = ArrayUtils.concatByteArrays( encrypted, result );
20        }
21        byte[] finalEncryptResult = cipher.doFinal();
22        encrypted = ArrayUtils.concatByteArrays( encrypted, finalEncryptResult );
23
24        cipher.init( Cipher.DECRYPT_MODE, key, ivParameterSpec );
25        byte[] decrypted = new byte[0];
26        for ( int i = 0; i < encrypted.length; i++ ) {
27            byte b = encrypted[i];
28            byte[] result = cipher.update( new byte[]{ b } );
29            decrypted = ArrayUtils.concatByteArrays( decrypted, result );
30        }
31        byte[] finalDecryptResult = cipher.doFinal();
32        decrypted = ArrayUtils.concatByteArrays( decrypted, finalDecryptResult );
33
34        String decryptedText = new String( decrypted );
35        System.out.println( test );
36        System.out.println( decryptedText );
37    }
38}