First, grab this userscript to use GET over SSL when Scroogling. I can’t claim to fully understand what it does but it sure does sound secure. (Isn’t that comforting? Hey, at least I’m not giving you a false sense of security by claiming to know better than I really do.)
Next, pick up Scroogle With, an extension I hacked to replace Google with Scroogle when using the context menu’s Search With option. I don’t know if installing Scroogle as Firefox’s search engine would do the same, but my extension has the added feature of working with text boxes. I don’t use the built-in search box that Firefox has. If you do, you might want to install Scroogle there too.
Finally, install this userscript to skip between languages in Scroogle results pages. This isn’t really necessary, it’s just a convenience for us who’d like Google results in languages other than English from time to time.
So you see, the path to security here is through installing a bunch of software from unknown sources! (Just kidding of course. Since the code is out in the open, you’re free to audit it personally any time you like.)