Authentication is the process of validating a user’s identity. When a user attempts to log in, authentication involves verifying their credentials against those stored in an authentication server or local operating system. If the credentials match, the user is allowed access. Most systems prefer using a two-factor authentication process for enhanced security.

An authentication factor is a security credential that verifies the identity of a user by trying to gain access to, request data from, or send communications to any secured network, application, or system.

What are the Categories of Authentication?

There are mainly five authentication factor categories, each with different functionalities.

Here is a list of them and how they work:

  1. Knowledge factors: The knowledge factor is an authentication process through which the user provides information or data before accessing the secured system. Knowledge-based authentication factors include a password or a personal identification number (PIN) that restricts a system’s access. Most commonly, applications or network logins use a username/e-mail address and a respective PIN or password to gain access to the system.
  2. Possession factors: These possession factors involve requiring the user to possess a specific piece of information before they can acquire access or entry to the system. Possession factors are controlled mainly through a device known to belong to the right user. Possession-based factor authentication includes the one-time password system where an OTP is automatically generated and sent to the user via SMS, which can then be used to access the system.
  3. Inherence factors: Inherence is an authentication process in which unique features verify the user’s credentials. Examples of these features used in inherence factors include- thumbprints, fingerprints, palm or handprints, facial and voice recognition, and retina or iris scans.
  4. Location factors: Location-based authentication factors include the implementation of services that deploy geolocation security checks to verify the user’s exact location and grant access accordingly to a network, application, or system. Geolocation security helps ensure that only users of a particular geographic area can access any application, network, or system.
  5. Behavior factors: Behavior factors authenticate users and give them access to the system based on their actions. Behavior-based authentication allows users to pre-configure a password in the system by performing a behavior within a defined interface, such as drawing a specific pattern onto a grid of dots and later repeating them as a mode of identification. The lock screens used in mobile phones are a prime example of behavior-based authentication.

What is 2FA?

As its name suggests, two-factor authentication (2FA) is a security process using two different authentication factors to verify themselves. Two-factor authentication is also sometimes known as dual-factor authentication or two-step authentication.

Why is it Needed?

Deploying 2FA better helps in protecting both the user’s resources they can access and the user credentials. 2FA provides better security than single-factor authentication methods, which typically use only a passcode or a password. 2FA relies on the user providing first a password and second a different factor- usually, it includes a biometric factor such as a facial scan or a fingerprint and a security token. By adding a layer of security, 2FA makes it close to impossible for hijackers to gain access to the user’s devices or online accounts.

Benefits & Drawbacks

While it is undeniable that authentication factors improve security by elevating the verification process to a two-step process, 2FA schemes can still be vulnerable to certain shortcomings. For example, hardware tokens depend on the manufacturer’s or issuer’s security. Thus, if that is compromised, it is easy for hijackers to bypass the two-factor system.

The account recovery process can also be manipulated to bypass the two-factor system- it allows for resetting of the user’s password and provides a temporary password via email that allows the user to re-login, thus bypassing the 2FA process.

While SMS-based 2FA is economical, user-friendly, and easy to implement, it is also vulnerable to multiple attacks. The SMS can easily be hacked through phone number portability attacks, mobile phone networks, and malware attacks.

Examples of 2FA

There are numerous different devices and services through which we can implement 2FA. Some of these include- tokens, radio frequency identification (RFID) cards, Smartphone apps, etc. Broadly, two-factor authentication products are separated into two categories:

  1. Tokens are provided to users for use during the time of login
  2. Software or infrastructures recognize and authenticate access for only those users who have used their tokens rightly.

Authentication tokens are either physical, for example, smartcards or key fobs, or can exist as software in desktop or mobile apps. These should be able to generate PIN codes for authentication.

Accounts where you Should Enable 2FA

Two-factor authentication is a common process to restrict access to sensitive data and systems. Here is the list of some of the standard accounts that should have 2FA enabled to avoid intruder access:

  • Credit and debit card accounts.
  • Checking and savings accounts.
  • Accounting and bookkeeping service accounts.
  • Investment accounts.
  • Loan accounts.
  • Tax filing service accounts
  • Foreign currency accounts.
  • Mortgage accounts

Tips for Best Password Security

Below listed are best practices to secure user passwords and guard their account against external attacks:

  • Use different passwords for every account
  • Never disclose passwords to others
  • Use 2FA or multi-factor authentication (MFA)
  • Make the password more complex
  • Making the password lengthy makes it more difficult to hack
  • Make passwords that are easy to remember but hard to guess.
  • Use a password manager.


With the rise of internet crime and identity theft, it is vital to have a secure login to all accounts. Two Factor Authentication is a very effective way to add a layer of security to all online accounts. It is a form of multi-factor authentication, meaning the user will need more than just a username and a password to access your account. Many companies and websites are adopting two-factor authentication to give their users an extra layer of security, and the adoption of 2-factor authentication is expected to increase further.


What is 2-factor authentication? How does it work?

2-factor authentication authenticates the user’s identity by two or more factors: for example, it can use a passcode as the first authenticating factor and then require biometric information such as a fingerprint as its second.

What is a two-factor authentication example?

Using two knowledge factors, such as a PIN and a password, is a two-step authentication.

What is the difference between a password and two-factor authentication?

Password-based authentication requires only the password to verify the user credentials. However, a 2FA requires additional proof next to the password, making the authentication process more complex and secure.