Securely Sign an XML file?

[Dave]

Hello,

I have an application using Visual Studio 2005 that I use that
generates XML data files. Obviously being XML the files can be edited
in Notepad by people.

I would like to sign the XML files so that once the application has
written the XML and the file is viewed later that I know that the XML
file has not been tampered by a user.

Is this possible - if so please could you give me some pointers to
where I would start?



Thanks,



Dave