A brief introduction to the working principle of two-Factor Authentication (2FA)

What is two-factor authentication (2FA)?

Two-factor authentication is an authentication system that works by combining what you know and what you have. Two-factor authentication is a time-synchronization system, which uses one-time cipher based on time, event and key to replace traditional static cipher. Each dynamic password card has a unique key, which is stored at the server side at the same time. During each authentication, the dynamic password card and the server calculate the dynamic password for authentication according to the same key, the same random parameters (time, event) and the same algorithm, so as to ensure the consistency of the password, thus realizing the authentication of the user. Quoted from Baidu Encyclopedia

Generally speaking, there are three different types of evidence that can prove a person's identity.

Secret information: information known only to the user and unknown to others, such as passwords.

Personal items: personal items of the user, such as keys, etc.

Physiological characteristics: The genetic characteristics of the user, such as fingerprints, facial features, iris, etc.

This evidence is called the three "factors." The more factors, the stronger the probative power, the more reliable the identity.

Two-factor authentication means that evidence of both factors is required to pass the authentication.

Bank cards are the most common two-factor authentication. Users must have both card number and password in order to withdraw cash.