innerContent.write(kerberosOid.getEncoded());
        innerContent.write(0x01); // magic byte 1
        innerContent.write(0x00); // magic byte 2

        // Add a sequence instead of APPLICATION tagged object
        DERSequence wrongTag = new DERSequence(new ASN1Encodable[] { new ASN1Integer(5) });
        innerContent.write(wrongTag.getEncoded());

        byte[] content = innerContent.toByteArray();

        elementVector.add(new DERTaggedObject(1, new DEROctetString(new byte[] { 0x01, 0x02 }))); // authData
        authVector.add(new DERSequence(elementVector));

        byte[] token = new DERSequence(authVector).getEncoded();
        Map<Integer, KerberosKey> keys = new HashMap<>();

        // 2. WHEN
        KerberosRelevantAuthData relevantAuthData = new KerberosRelevantAuthData(token, keys);

        // 3. THEN

            @Override
            public ASN1Primitive toASN1Primitive() {
                // Return a primitive that will throw IOException when getEncoded is called
                return new DEROctetString(new byte[0]) {
                    @Override
                    public byte[] getEncoded() throws IOException {
                        throw new IOException("encode failure");
                    }
                };
            }

        vector.add(new DERTaggedObject(10, new DERSequence(authDataVector)));

        DERSequence sequence = new DERSequence(vector);
        byte[] encoded = new DERTaggedObject(false, BERTags.APPLICATION, 1, sequence).getEncoded();

        KerberosEncData encData = new KerberosEncData(encoded, Collections.emptyMap());

        assertEquals("TEST.REALM", encData.getUserRealm());
        assertEquals("testuser", encData.getUserPrincipalName());

        return new ASN1ObjectIdentifier("1.2.840.113554.1.2.2");
    }

    private static byte[] oidDer() {
        // Full DER encoding of the OID
        try {
            return testOid().toASN1Primitive().getEncoded();
        } catch (java.io.IOException e) {
            throw new RuntimeException(e);
        }
    }

    @Test
    @DisplayName("Parses a valid buffer and exposes fields")
    void parseValidBuffer() {

        // Test successful reading and casting from ASN1InputStream
        ASN1Integer original = new ASN1Integer(456);
        ByteArrayInputStream bais = new ByteArrayInputStream(original.getEncoded());
        ASN1InputStream ais = new ASN1InputStream(bais);
        ASN1Integer result = ASN1Util.as(ASN1Integer.class, ais);
        assertEquals(original, result);
    }

    @Test

                    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;
            case 4:

        Cipher cipher;
        byte[] decrypt;
        byte[] code = new byte[4];
        Encdec.enc_uint32le(2, code, 0);
        byte[] codeHmac = getHmac(code, key.getEncoded());

        byte[] dataChecksum = new byte[KerberosConstants.CHECKSUM_SIZE];
        System.arraycopy(data, 0, dataChecksum, 0, KerberosConstants.CHECKSUM_SIZE);

        if (unknownTag != null) {
            v.add(new DERTaggedObject(true, unknownTag, new DERGeneralString("unknown")));
        }

        return new DERSequence(v).getEncoded();
    }

    /**
     * Creates a byte array representing the decrypted data part of a Kerberos ticket.
     * @param userName User principal name
     * @param userRealm User realm

     * @throws GeneralSecurityException if cryptographic operations fail
     */
    public static byte[] deriveKeyAES(KerberosKey key, byte[] constant) throws GeneralSecurityException {
        byte[] keybytes = key.getEncoded();
        Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
        cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(keybytes, "AES"), new IvParameterSpec(ZERO_IV, 0, ZERO_IV.length));