TOTP stands for “Time-based One-Time Password” and refers to a time-limited one-time password used for user authentication. TOTP generates a unique code that is renewed at regular time intervals, usually every 30 seconds.
How Does TOTP Work?
1. Time-based:
TOTP codes are based on a secret key and the current time. The time factor makes these codes valid for only a short duration, which enhances security.
2. Synchronization:
Both the server and the user’s device (e.g., a smartphone with an authenticator app) need to be synchronized so that the generated codes match and can be verified correctly.
3. Algorithm:
The TOTP algorithm is standardized (e.g., RFC 6238) and uses the secret key and the current time to produce the one-time code. Common implementations are based on HMAC-SHA-1.
Using TOTP in Multi-Factor Authentication (MFA):
1. Registration and Setup:
When setting up TOTP-authenticated accounts, a secret key is created. This key is entered into an authenticator app like Google Authenticator, Authy, or Microsoft Authenticator via a QR code or manually.
2. Login:
- The user first enters their username and password (first security layer).
- As a second security layer, the user is prompted to enter the current TOTP code from their authenticator app.
- The server verifies whether the entered code matches the expected TOTP. If so, access is granted.
Advantages of TOTP:
1. Enhanced Security:
Since TOTP codes are valid for only a short period, security is significantly increased. An intercepted code can hardly be reused.
2. Phishing Protection:
Even if an attacker knows a user’s password, they also need the current TOTP code, which constantly changes.
3. Simple and Cost-Effective:
The implementation of TOTP is relatively simple and does not require expensive hardware components. Smartphones are sufficient to serve as the second factor.
Conclusion:
TOTP offers an effective and user-friendly method to enhance security within the framework of multi-factor authentication. By introducing a time-limited one-time code, the risk of unauthorized access is significantly reduced.