Saving XML file content in binary format

Hi gents,

I have a questions which is more a general question than the Rhino question I guess but since I want to do it within Rhino plugin - makes sense to list it here.

Actually main message is already in the header.
At the moment I can easily read and write XML files, however I would like to have them saved in the binary form - in order not be read externally.

Can you guide for a smart way to do this?

Kind regards,

Thanks Steve