byte[] originalResult = originalHmac.engineDigest();
        byte[] clonedResult = clonedHmac.engineDigest();

        assertArrayEquals(originalResult, clonedResult);
    }

    @Test
    void testMultipleUpdates() {
        // Test multiple update calls
        HMACT64 hmac1 = new HMACT64(TEST_KEY);
        HMACT64 hmac2 = new HMACT64(TEST_KEY);

        // Update hmac1 all at once