SecretKeySpec dataKey = new SecretKeySpec(dataHmac, KerberosConstants.RC4_ALGORITHM);

        cipher = Cipher.getInstance(KerberosConstants.RC4_ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, dataKey);

        int plainDataLength = data.length - KerberosConstants.CHECKSUM_SIZE;
        byte[] plainData = cipher.doFinal(data, KerberosConstants.CHECKSUM_SIZE, plainDataLength);

     * @param key
     * @throws GeneralSecurityException
     */
    private static void verifyAESMAC ( int usage, String expect, String data, String key ) throws GeneralSecurityException {
        verifyAESHMAC(usage, expect, key, Hex.decode(data));
    }


    private static void verifyArcfourHMAC ( int usage, String expect, String data, String key ) throws GeneralSecurityException {

public class NegTokenInit extends SpnegoToken {

    public static final int DELEGATION = 0x80;
    public static final int MUTUAL_AUTHENTICATION = 0x40;
    public static final int REPLAY_DETECTION = 0x20;
    public static final int SEQUENCE_CHECKING = 0x10;
    public static final int ANONYMITY = 0x08;
    public static final int CONFIDENTIALITY = 0x04;
    public static final int INTEGRITY = 0x02;

     * @throws IOException
     */
    public static byte[] readUnparsedTagged(int expectTag, int limit, ASN1InputStream in) throws IOException {
        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];

            if ( credential instanceof KerberosKey )
                serverKeys.add((KerberosKey) credential);

        return serverKeys.toArray(new KerberosKey[0]);
    }


    public KerberosKey getKey ( int keyType ) {
        KerberosKey serverKey = null;

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

                throw new PACDecodingException("Not a kerberos token");


            // yes, there really is non ASN.1/DER data inside the tagged object
            int read = 0;
            int readLow = stream.read() & 0xff;
            int readHigh = stream.read() & 0xff;
            read = ( readHigh << 8 ) + readLow;
            if ( read != 0x01 )
                throw new PACDecodingException("Malformed kerberos token");