TOTP stands for "Time-based One-Time Password" and is an authentication algorithm that generates unique temporary passwords for secure access to online accounts.
These passwords are generated from an algorithm that combines a secret key shared between the service provider and the user with the current time, usually using a mobile authentication app. Every 30 seconds, a new password is generated and is only valid for a short period of time, making TOTP much more secure than static passwords or confirmation SMS.