* @param data the data to calculate the MAC for
     * @return the calculated MAC bytes
     * @throws GeneralSecurityException if cryptographic operations fail
     */
    public static byte[] calculateMacArcfourHMACMD5(int keyusage, Key key, byte[] data) throws GeneralSecurityException {
        int ms_usage = mapArcfourMD5KeyUsage(keyusage);
        Mac mac = Mac.getInstance("HmacMD5");

        SecretKeySpec key = new SecretKeySpec(new byte[16], "ARCFOUR");
        byte[] mac = PacMac.calculateMacArcfourHMACMD5(3, key, TEST_DATA);
        assertNotNull(mac);
        assertEquals(16, mac.length);

        // Test with a different key usage
        byte[] mac2 = PacMac.calculateMacArcfourHMACMD5(9, key, TEST_DATA);
        assertNotNull(mac2);
        assertEquals(16, mac2.length);