Why using facial recognition on your phone could leave you vulnerable

Biometric authentication—the ability to unlock your devices by using just your face or fingerprint—is one of the few smartphone features that, even today, leave me feeling like we’re living in the future. When I was a kid, technology like facial recognition was limited to science fiction. But as cool and useful as biometric authentication is, the technology can also leave us vulnerable. Here’s why—and how to protect yourself.

It’s not just journalists and activists who can have their...