Protecting XML File While Displayed In Browser

From: John Bowman (john.bowman_at_thermo.com)
Date: 04/28/04 

Date: Wed, 28 Apr 2004 07:38:14 -0500

Hi,

I'm hoping this is the right place to post this Q. So if it's not, please
direct me otherwise.

I've got a simple win forms app (C#) I've been asked to modify that
generates numerical scientific data as XML and displays it in a grid
control. The user is allowed to generate a report of the data. To do this, a
temp XML file containig the portion of the results to display is apparently
generated and loaded into the default browser using a style *** to make it
look pretty. This is where the user would normally print his/her results.
Here's the problem. the XML data file is digitally signed, so when the
browser is loaded w/ the temp XML file, the user could technically modify
the data (through View Source, or any other text editor) while it's open in
the browser, then print it in a modified form and no one would ever know
that the results had been modified for printing purposes. This of course
defeats the digital signature. Is there any way to "protect" the temp file
that is loaded into the browser such that NO alterations can be made to it
between the time it is loaded into the browser and the user chooses to print
the displayed results?

I'm afraid I'm such a newbie at digital signature stuff that I'm not even
certain what approach to take here. Is there some other much more "safe"
approach to displaying and printing signed XML data? The above approach
certainly has it's holes.

TIA, 

-- 
John C. Bowman
Software Engineer
Thermo Electron Scientific Instruments Div.
<Remove this before reply> john.bowman@thermo.com