if ( constructed == null || constructed.getTagClass() != BERTags.APPLICATION ||
                    !(constructed.getBaseObject() instanceof  ASN1Sequence) )
                throw new IOException("Malformed SPNEGO token " + constructed);

            ASN1Sequence vec = (ASN1Sequence) constructed.getBaseObject();


                ASN1ObjectIdentifier spnego = (ASN1ObjectIdentifier) vec.getObjectAt(0);

            if ( mechToken == null || mechToken.getTagClass() != BERTags.APPLICATION ||
                    !(mechToken.getBaseObject() instanceof ASN1Sequence) )
                throw new PACDecodingException("Malformed kerberos token");

            this.apRequest = new KerberosApRequest((ASN1Sequence) mechToken.getBaseObject(), keys);
        }
        catch ( IOException e ) {

                    throw new PACDecodingException("Malformed Kerberos Ticket");
                try {
                    this.ticket = new KerberosTicket(derTicket.getBaseObject().getEncoded(), this.apOptions, keys);
                } catch (IOException e) {
                    throw new PACDecodingException("Malformed Kerberos Ticket", e);
                }
                break;

     * @throws PACDecodingException
     */
    public static <T extends ASN1Primitive> T as ( Class<T> type, ASN1TaggedObject tagged ) throws PACDecodingException {
        return as(type, tagged.getBaseObject());
    }

    /**
     *
     * @param type
     * @param sequence
     * @param index
     * @return sequence element cast to type
     * @throws PACDecodingException
     */

            throw new PACDecodingException("Malformed kerberos ticket", e);
        }

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

        Enumeration<?> fields = sequence.getObjects();