“Passwords are secret and dynamic; fingerprints are public and permanent,” Franken wrote. “If you don’t tell anyone your password, no one will know what it is. If someone hacks your password, you can change it — as many times as you want. You can’t change your fingerprints. You have only ten of them. And you leave them on everything you touch; they are definitely not a secret. What’s more, a password doesn’t uniquely identify its owner — a fingerprint does. Let me put it this way: if hackers get a hold of your thumbprint, they could use it to identify and impersonate you for the rest of your life.”