How to add "startpage" as default search engine in Firefox?

StartPage is a search engine will proxy your search to Google but without giving your data to it. In another word, it can give you the same result as Google but protect your privacy.

It is really easy o make it as your default search engine in the address bar in Firefox. If you open the "Perference" in Firefox, and on the "search" part you will see a search engine list similar to this:

So there is no "Start Page" there. You can now go to "startpage.com", then on the right of the address bar, click the "dot dot dot" to see more options, from where you can see "Add Search Engine" option, simply click it.

Now go back to the "Preference" page, in the "search engine" dropdown list, you can select "Start Page" as your default search engine. Next time, when you type some keyword in the address bar, Firefox will auto do the search in Start Page.