We are able, I think. Say, my bank calls me and ask to call back with an extension#. I look up their phone # on their website, call that number, and provide th

We are able, I think. Say, my bank calls me and ask to call back with an extension#. I look up their phone # on their website, call that number, and provide the extension. They know who I am via The extension # I gave back to them, I know who they are via their phone # confirmed by their website SSL certificate. Alternatively, I call them back on the phone number at the back of the credit card.