Webbrowser control security

I am using the Windows.Forms WebBrowser control in my ASP.Net app as a wrapper for the IE ActiveX control.

I already need to do the work with the control in a separate STA thread, so my question is what would be the best principal  to use on that thread to ensure the best security when working with pages? I want to run the browser with the least privileges possible.

What would be the best for security:
-Using the default generic Identity
-Using WindowsIdentity.GetAnonymous
-Or creating an account for this purpose and impersonating it

 Thanks!
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