byte[] result = hmac.engineDigest();

        assertNotNull(result);
        assertEquals(16, result.length);
    }

    @Test
    void testResetAndReuse() {
        // Test that HMACT64 can be reset and reused
        HMACT64 hmac = new HMACT64(TEST_KEY);

        // First use
        hmac.engineUpdate(TEST_DATA, 0, TEST_DATA.length);