How can I choose a different client certificate in Firefox?

Question

When I choose a client certificate in Firefox (or cancel choosing none), Firefox seems to remember this decision even though I've told it to ask me every time. I understand that it'd be useless for Firefox to ask me every page load, so of course it's remembering my decision for the length of whatever it thinks of as a session, but how can I change that selection or close that session? It's not a per-tab decision...

Thanks!

Answer 1

The most straightforward way to indicate Firefox that you want to be asked every time for the right certificate is to adjust the security.default_personal_cert property in "Advanced Preferences". I have not found a way to do it through the "Options" menu, which is the recommended and safe way to change your Firefox preferences.

How to proceed:

1. Access Firefox's "Advanced Preferences" by opening a new tab and typing about:config into the address bar
2. Firefox will display a "Proceed with caution" warning. Click on "Accept the risk and continue".
3. On the "Search preference name" bar, type security.default_personal_cert
4. Set the value of that property to Ask Every Time
5. Close the tab (make sure that you do not change anything else)

You are done. If a website needs a certificate, you will now be asked to choose one from the list instead of having it automatically selected.

(Note: I am using Firefox 85.0 (64-bit) on Windows 10. If I am not wrong, previous versions of Firefox allowed to change that preference from "Options".)

Answer 2

You need to clear SSL session state of your browser. Take a look at my anwer to a similar question:

in Firefox choose History -> Clear Recent History... and then select "Active Logins" and click "Clear Now".