}
        catch ( GeneralSecurityException e ) {
            throw new GeneralSecurityException("Checksum failed while decrypting.");
        }
        byte[] ivec = new byte[8];
        IvParameterSpec params = new IvParameterSpec(ivec);

        SecretKeySpec skSpec = new SecretKeySpec(key.getEncoded(), "DES");
        SecretKey sk = skSpec;

        if ( token.length <= 0 )
            throw new PACDecodingException("Empty kerberos ticket");

        ASN1Sequence sequence;
        try {
            try ( ASN1InputStream stream = new ASN1InputStream(new ByteArrayInputStream(token)) ) {
                sequence = ASN1Util.as(ASN1Sequence.class, stream);
            }
        }
        catch ( IOException e ) {
            throw new PACDecodingException("Malformed kerberos ticket", e);

        try {
            try ( ASN1InputStream stream = new ASN1InputStream(new ByteArrayInputStream(token)) ) {
                authSequence = ASN1Util.as(ASN1Sequence.class, stream);
            }
        }
        catch ( IOException e ) {
            throw new PACDecodingException("Malformed kerberos ticket", e);
        }

        this.authorizations = new ArrayList<>();

        NegTokenInit negInit = new NegTokenInit(mechToken);
        byte[] krbToken = negInit.getMechanismToken();


        Path p = Files.createTempFile("fakeserver", ".keytab");
        try {
            Files.write(p, keyTab);
            KeyTab kt = KeyTab.getInstance(p.toFile());

            if ( mechanismListMIC != null ) {
                fields.add(new DERTaggedObject(true, 3, new DEROctetString(mechanismListMIC)));
            }

            ASN1EncodableVector ev = new ASN1EncodableVector();
            ev.add(SPNEGO_OID);
            ev.add(new DERTaggedObject(true, 0, new DERSequence(fields)));
            ByteArrayOutputStream collector = new ByteArrayOutputStream();

        if ( token.length <= 0 )
            throw new PACDecodingException("Empty kerberos ApReq");

        ASN1Sequence sequence;
        try {
            try ( ASN1InputStream stream = new ASN1InputStream(new ByteArrayInputStream(token)) ) {
                sequence = ASN1Util.as(ASN1Sequence.class, stream);
            }
        }
        catch ( IOException e ) {
            throw new PACDecodingException("Malformed Kerberos Ticket", e);

        if ( token.length <= 0 )
            throw new PACDecodingException("Empty kerberos token");

        byte[] content;
        try ( ASN1InputStream stream = new ASN1InputStream(token) ) {
            content = ASN1Util.readUnparsedTagged(0, 0x8000, stream);
        }catch ( IOException e ) {
            throw new PACDecodingException("Malformed kerberos token", e);
        }

        int ftag = in.read();
        int tag = readTagNumber(in, ftag);
        if ( tag != expectTag ) {
            throw new IOException("Unexpected tag " + tag);
        }
        int length = readLength(in, limit, false);
        byte[] content = new byte[length];
        in.read(content);
        return content;
    }

    // shamelessly stolen from BC ASN1InputStream

    }


    public KerberosCredentials ( String loginContextName ) throws LoginException {
        LoginContext lc = new LoginContext(loginContextName);
        lc.login();
        this.subject = lc.getSubject();
    }


    public KerberosKey[] getKeys () {
        List<Key> serverKeys = new ArrayList<>();

        Set<Object> serverPrivateCredentials = this.subject.getPrivateCredentials();