TOTP

TOTP — time-based one-time password — is the six-digit code that rotates every thirty seconds in an authenticator app like 1Password, Authy, or Google Authenticator. It's one of the most common second factors for multi-factor authentication.

It works without any network connection. Your device and the service share a secret when you first set it up, and both independently compute the same code from that secret plus the current time. Because the codes are generated locally rather than sent over a network, TOTP is meaningfully more secure than codes delivered by SMS, which can be intercepted or redirected.

The practical advice: store your TOTP secrets in your password manager alongside the credentials they protect. That keeps your second factors organized, backed up, and recoverable when a device is lost — rather than stranded on a single phone.