public SymmetricEncryptionConfig setKey(byte[] key) {
        this.key = cloneKey(key);
        return this;
    }
@Test
    public void testSetKey() {
        byte[] key = new byte[]{23, 42};
        config.setKey(key);

        assertEquals(key[0], config.getKey()[0]);
        assertEquals(key[1], config.getKey()[1]);
    }