// Then
        assertNotNull(hash);
        assertEquals(16, hash.length); // MD5 produces 128-bit hash
    }

    @Test
    @DisplayName("Should calculate HMAC-T64 correctly")
    void testHMACT64() {
        // Given
        byte[] key = "secret".getBytes();
        byte[] data = "Hello World".getBytes();

        // When
        MessageDigest hmac = Crypto.getHMACT64(key);