assertNotNull(md5Hash);
        assertEquals(16, md4Hash.length);
        assertEquals(16, md5Hash.length);
    }

    @Test
    @DisplayName("Should handle null input gracefully")
    void testNullInputHandling() {
        // When/Then
        assertThrows(NullPointerException.class, () -> {
            MessageDigest md4 = Crypto.getMD4();
            md4.digest(null);
        });