* @return the mechanism OID
     */
    public ASN1ObjectIdentifier getMechanism() {
        return this.mechanism;
    }

    /**
     * Sets the selected authentication mechanism OID
     * @param mechanism the mechanism OID to set
     */
    public void setMechanism(final ASN1ObjectIdentifier mechanism) {
        this.mechanism = mechanism;
    }

    @Override

    void testEmptyMechanismToken() throws IOException {
        NegTokenTarg nt = new NegTokenTarg();
        nt.setResult(NegTokenTarg.REQUEST_MIC);
        nt.setMechanismToken(new byte[0]); // empty but non‑null
        nt.setMechanism(new ASN1ObjectIdentifier("2.16.840.1.101.3.6.1"));
        nt.setMechanismListMIC(null);
        byte[] bytes = nt.toByteArray();
        NegTokenTarg parsed = new NegTokenTarg(bytes);