private static final byte[] ZERO_IV = new byte[] {
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
    };


    public static byte[] calculateMacArcfourHMACMD5 ( int keyusage, Key key, byte[] data ) throws GeneralSecurityException {
        int ms_usage = mapArcfourMD5KeyUsage(keyusage);
        Mac mac = Mac.getInstance("HmacMD5");