/**
     * Specifies that communication across the authenticated channel
     * should carry a digital signature (message integrity).
     */
    public static final int NTLMSSP_NEGOTIATE_SIGN = 0x00000010;

    /**
     * Specifies that communication across the authenticated channel
     * should be encrypted (message confidentiality).
     */
    public static final int NTLMSSP_NEGOTIATE_SEAL = 0x00000020;

                            clientChallenge);

                setLMResponse(clientChallenge);
                setNTResponse(ntlm2Response);

                if ((getFlags() & NTLMSSP_NEGOTIATE_SIGN) == NTLMSSP_NEGOTIATE_SIGN) {
                    byte[] sessionNonce = new byte[16];
                    System.arraycopy(type2.getChallenge(), 0, sessionNonce, 0, 8);

                throw new CIFSException("Failed to encrypt MIC", e);
            }
        }

        byte[] sig = new byte[16];
        SMBUtil.writeInt4(1, sig, 0); // version
        System.arraycopy(trunc, 0, sig, 4, 8); // checksum
        SMBUtil.writeInt4(seqNum, sig, 12); // seqNum

        return sig;
    }


    @Override
    public void verifyMIC ( byte[] data, byte[] mic ) throws CIFSException {

     *
     * @param data The data.
     * @param offset The starting offset at which the SMB header begins.
     * @param length The length of the SMB data starting at offset. 
     */
    void sign(byte[] data, int offset, int length,
                ServerMessageBlock request, ServerMessageBlock response) {
        request.signSeq = signSequence;
        if( response != null ) {

        if ( ( flags & ServerMessageBlock2.SMB2_FLAGS_SIGNED ) == 0 ) {
            log.error("The server did not sign a message we expected to be signed");
            return true;
        }

        byte[] sig = new byte[SIGNATURE_LENGTH];
        System.arraycopy(data, offset + SIGNATURE_OFFSET, sig, 0, SIGNATURE_LENGTH);

        int index = offset + SIGNATURE_OFFSET;
        for ( int i = 0; i < SIGNATURE_LENGTH; i++ )

        dstIndex += writeHeaderWireFormat( dst, dstIndex );
        dstIndex += writeAndXWireFormat( dst, dstIndex );
        length = dstIndex - start;

        if( digest != null ) {
            digest.sign( dst, headerStart, length, this, response );
        }

        return length;
    }

    /*
     * We overload this because we want readAndXWireFormat to
     * read the parameter words and bytes. This is so when

                NtlmFlags.NTLMSSP_NEGOTIATE_NTLM2 |
                NtlmFlags.NTLMSSP_NEGOTIATE_128;
        if (doSigning) {
            this.ntlmsspFlags |= NtlmFlags.NTLMSSP_NEGOTIATE_SIGN |
                NtlmFlags.NTLMSSP_NEGOTIATE_ALWAYS_SIGN |
                NtlmFlags.NTLMSSP_NEGOTIATE_KEY_EXCH;
        }
        this.workstation = Type1Message.getDefaultWorkstation();
        log = LogStream.getInstance();
    }

        return b;
    }


    /**
     * {@inheritDoc}
     *
     * @see jcifs.internal.SMBSigningDigest#sign(byte[], int, int, jcifs.internal.CommonServerMessageBlock,
     *      jcifs.internal.CommonServerMessageBlock)
     */
    @Override
    public void sign ( byte[] data, int offset, int length, CommonServerMessageBlock request, CommonServerMessageBlock response ) {
        if ( log.isTraceEnabled() ) {

    /**
    * Specifies that communication across the authenticated channel
    * should carry a digital signature (message integrity).
    */
    public static final int NTLMSSP_NEGOTIATE_SIGN = 0x00000010;

    /**
    * Specifies that communication across the authenticated channel
    * should be encrypted (message confidentiality).
    */
    public static final int NTLMSSP_NEGOTIATE_SEAL = 0x00000020;

     * @param length
     *            The length of the SMB data starting at offset.
     * @param request
     *            request message
     * @param response
     *            response message
     */
    void sign ( byte[] data, int offset, int length, CommonServerMessageBlock request, CommonServerMessageBlock response );


    /**
     * Performs MAC signature verification. This calculates the signature