TOTP is effectively a cryptographic hash(shared-secret, time) producing 6 decimal digits where time gets incremented every 30s. The server accepts the token if

TOTP is effectively a cryptographic hash(shared-secret, time) producing 6 decimal digits where time gets incremented every 30s. The server accepts the token if it's recent enough. Many desktop password managers have built in support (e.g. keepass2).