How many movies and TV shows have you seen where asks somebody else about a secret that they share? If they give the right answer, their identity is confirmed. If they don’t, they’re an imposter, an alien from Planet X in disguise.
Shared secrets are the basis of authentication in computer security. And two shared secrets – two factor – are even better than one, especially when the first is a password that many people have difficulty managing in a secure way. This is what we’re doing when we use both a password and a code that’s texted to us. And this week, we got told to stop using text messages for the second secret.