"Passwords are secret and dynamic; fingerprints are public and permanent," wrote Sen. Franken. "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."