We discuss authentication from the perspective of computers and users. For this discussion, pivot to consider the modern world and human-to-human interactions. We are often faced with authenticating people we don’t know in various ways. For example, this might be an in-person Craigslist transaction in a parking lot, a blind date arranged from a dating app, or an official (police or contractor) showing up at your door. How do you authenticate someone in the real world? What mechanisms are used to positively identify and confirm their identities? Each of those scenarios may have different strategies, so pick two distinct scenarios to discuss and compare.