Two-factor authentication methods may differ. However, there are standards for the implementation of this process.

A 2FA transaction usually proceeds as follows:

– The user enters their login credentials to access the website or service.

– The authentication server checks the password, and if it is correct, the user proceeds to the second stage of verification.

– The authentication server sends a unique code to the user’s device.

– By passing additional authentication, the user confirms his identity and gets access to the account.

Although the basic processes of multi-factor authentication are basically the same, there are many different ways to implement it, and not all approaches are similar. It’s time to consider different types of 2FA.

Types of two-factor authentication

It’s worth taking a look at how popular websites and apps are implementing 2FA these days. There are various types of two-factor authentication:

– by email;

– by SMS;

– voice 2FA;

– biometric 2FA;

– using an authenticator application; based on hardware tokens; using a software token or TOTP.


Companies and services use the above authentication types to provide an additional level of security for their customers and users.