This crucial piece of information, often represented as a string of characters, serves as the foundational link between an individual’s account on a service and their authenticator application. It’s the digital handshake that enables the app to generate time-based one-time passwords (TOTPs) used during the two-factor authentication process. For example, when setting up 2FA for a website, the site will display either a QR code or a textual representation of this string; scanning the QR code or manually entering the text into the authenticator app establishes the secure connection.
Its importance lies in enabling a more secure login process, reducing the risk of unauthorized access even if a password is compromised. By requiring a second factor of authentication the TOTP generated using this key it adds a substantial layer of protection. Historically, this method evolved from simpler forms of two-factor authentication, like SMS codes, to offer a more robust and phishing-resistant security measure.