Hi,
You could "obfuscate" the URL the user sees by using URL Rewrite.
Look at my article how this is done:
How-to: Create an easy and flexible URL-Rewriter[
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By using URL Rewriting, you can hide the effective URL parameters from the client, that he only knows the user-friendly URL without any .aspx / query string parameters.
Hope this helps.
Have a nice day and happy coding,
Chris