One of the most popular method of authentication remains the password. In a previous article, we discussed the proper implementation of password authentication. However, relying solely on a password as the means of authentication is no longer sufficient, especially for critical accounts, such as bank accounts or personal email accounts, that serve as the point of access to other services.
Two-factor authentication (2FA) significantly enhances account security by adding an extra step in the login process. In this article, we will discuss 2FA options and take a closer look at implementations of the commonly used time-based one-time password (TOTP) and a password and HMAC-based one-time password (HOTP) protocols.