What Is Two-Factor Authentication (2FA) & How Does It Work?

Two-Factor Authentication

What is two-factor authentication? You see this term everywhere but still don’t know about it. 2FA or Two-Factor Authentication can also be called Dual Factor Authentication or Two-Step Verification. It is a two-step process where users have to verify themselves twice for authorization.

The two-factor authentication is there to protect the users from anyone else. Obviously, 2FA is much more protected than SFA (single-factor authentication). In SFA, you only have to use one factor of authentication. SFA is usually a passcode or password. In 2FA your passcode or password is the first authentication and after that, the second one is biometric (face unlock or fingerprint) or security token.

Single Factor Authentication

Hackers hate the 2FA because of its additional layer of protection. This means having 2FA makes your information and online accounts much more protected and safe. In 2FA, even if your password is compromised, your safety is not at risk because a second authentication is required.

Before this type of system was not used by many but recently many companies are motivating their users to use 2FA. Usually, hackers try to steal password databases for passcodes and passwords of users. Let us learn everything we can about two-factor authentication.

Two-Factor Authentication

There are many ways that can be used as a second way of authentication. Today, many 2FA are based on knowledge methods. Either the inherence factor or possession factor is used in the two-factor authentication.

Here are listed authentication factors adopted for computing.

1. Possession Factor

This factor refers to something that a user already owns. This could be anything like an ID card, cellphone, security card, application, etc. These possession items help to verify his or her identification.

2. Knowledge Factor

This refers to the knowledge of users which can show he or she knows something very confidential. This could be PIN (Personal Identification Number), password, etc. This could also be a question that could be only answered by the user. Usually while making the account, you will have to set an answer for a few questions so when they ask in the future you will be able to answer.

3. Biometric Factor

This is also called the inherence factor. It is something that is inherent physically in the user. The most common personal mapped attribute on the human body is the fingerprint. The 2FA could be a fingerprint that needs to be scanned by a fingerprint scanner. Some other useful biometric factors are voice and facial recognition. Or some behavioral inherence like speech patterns or keystroke gesture dynamics can also be used. The most common is fingerprint and that is why in many places you see the same factor.

4. Time Factor

This factor lets the authentication happen only at a specific time. If someone tries to log in at a different time the 2FA won’t allow access.

5. Location Factor

This refers to the authentication which is done by recognizing the location of the person who is trying to complete the authentication. This can be useful when you want a particular device to be only able to get through your authentication within a specific region. The source of the internet used by the device helps to know where that device is being operated. This system is called a GPS (Global Positioning System). Not used commonly by users but is something that is useful and secure.

The most common authentication factors are Knowledge, possession, and biometric factors. But other few are used when the security needs are too high. Some high-security systems even use multi-factor authentication where more than two authentication verifications are required. They are more secure and keep hackers at bay.

How Does Two-Factor Authentication Work?

The need for 2FA depends on the user and the service provider. The process is quite similar to your normal single-factor authentication. Just a few steps are added for security. Right now, almost all social media accounts recommend users have two-factor authentication. It also helps to recover your account in case of a breach.

Two-Factor Authentication
  • The user has to log in to a website or app.
  • They have to insert their basic information such as a username and a correct password. After this, the particular site analyzes its servers to match the username with the password and lets the user in.
  • If your process does not need passwords then the site usually generates a security key that is unique for you. After entering this key the server checks the authentication and verifies you.
  • Now, your site will move you to the second stage of login. This step can take a bit more time and can be offered in multiple ways. Here, you will have to provide something that is only limited to you. It could be a security code, biometric, smartphone, ID card, etc. This comes under the possession or inherence factor.
  • In the next step, you might receive an OTP (One Time Password). Enter this code to complete the stage.
  • After successfully completing both factors, you will get access to operate or use the site of the application.

There is nothing too complicated in this if you have used 2FA. If you remember, you usually have to go through such steps while accessing your online bank application or bank account.

Two-Factor Authentication Elements

If we see two-factor authentication can also be multi-factor authentication (MFA). MFA is using two or more authentication methods. So, when the service or system asks you for two authentications it can also come under MFA. But sometimes two factors can not be called 2FA. For instance, giving your password and secret answers comes under single-factor authentication. Because both password and secret answer come under the knowledge factor of authentication.

Talking about single-factor authentication, your password and username are not at all secure. The biggest problem with password authentication is that for a strong and long password, you will need diligence and knowledge.

Why Passwords are not considered strong? Because there are many threats that stand against them such as lying around sticky notes with some old HHDs, etc. Also, some external threats such as hackers and cyber attackers can easily break through your password.

With some time and hard work, a hacker can easily break through a password authentication factor to steal anything they want. Password authentication is still considered Single-factor authentication because of the low protection wall and easy-to-make systems.

Multiple questions for challenging authentication can create a much thicker wall of security. But it also depends on how you have implemented that. In SFA fingerprint, verification can be one of the strong types of factors. Easy and quick to use while being a better choice for safety.

Types Of Two-Factor Authentication Products

There are various services and devices that implement the 2FA. This can vary from radio frequency to tokens. These products can easily be divided into two categories.

  • Software or infrastructure that authenticates or recognizes access of users who are trying to use their token correctly.
  • The token is given to you while logging in.

These tokens are usually physical types of items like smart cards or key fobs or even be in your smartphone or smartwatch. Having a PIN code generator in your PC software can also be called a token product. The PIN code generator is commonly known as OTP (One Time Password). Generally, they are created by a server and then verified by software or application. OTP is temporary and links to your particular device or account. As the name suggests they are only used once.


The company or organization has to create a system that can process, accept, and then allow or deny the specific authentication token. This system could be a hardware, software, or third-party type of vendor.

Another concept the 2FA follows is to only let the user use for which they have verified themselves. This means 1 key of 2FA is always linked to the authentication system. And this system is linked to the authentication data of the organization. For instance, Microsoft only provides some chuck of necessary infrastructure to support the 2FA in Microsoft Windows 10. This is done through Windows Hello. This operates the Microsoft account while authenticating you (the user).

Smartphones Two Factor Authentication

Your phone has different capabilities for 2FA. Because of this, companies can construct their systems much more efficiently. Almost all smartphones today have a fingerprint sensor with a front camera that helps with facial unlock or even eye scan. The mic is used for speech recognition. For the location factor, the built-in smartphone GPS is used. For out-of-band authentication services, voice or SMS are used.

Your mobile number can provide you a verification code or OTP through a phone call or SMS. For smartphone 2FA, you will need to verify with one phone number.

Push Notification’s Two Factor Authentication

Here, no password is used for authentication, and instead, the verification of the user is done by sending a simple notification to a secured application on your device. This alerts the user (you) so you know someone has tried to authenticate. Usually, you can see some basic details in this push notification and have two options, one is accepted and the other is denied. This can be done within a few clicks. If you accept the sire or authenticator you will let you. Denying it will secure your account or authentication within seconds.

Push notifications are only sent to the device that is registered within the system. The most common device is a mobile and that is where you will receive this push notification. But in case of device compromisation, your notifications also get compromised. Things such as middleman attacks and unauthorized social engineering access can be avoided through push notifications.

Is 2FA Secured?

Yes, it does enhance your overall security but some of the 2FA schemes can make your component weaker. For instance, tokens in hardware totally depend on the manufacturer or issuer’s security. A recent and big incident relating to this is the compromise of 2FA of RSA Security company in 2011. Their authentication SecureID was hacked according to the company.

The hackers easily hacked the company’s chief executive’s email to get into their system. This does not mean that 2FA is bad or useless. It just means it is stronger than SFA but still it can be breached. Obviously, a company should have more authentication layers but for us normal users a 2FA is enough.

Final Words

There are many more places where 2FA can be applied and used. The future of two-factor authentication is solid and it will definitely help our security. Smartphone companies will keep working on their technology to provide much better compatibility. It is not a complex topic to understand but still, people don’t take it seriously.

If you don’t have 2FA on your social media accounts or on other services it is time you give it a try. There are many stories where this authentication failed but there are many more where it succeeded to protect the users. What are your thoughts on two-factor authentication?

By Vishal Negal

Meet Vishal Negal, a digital marketer and tech enthusiast with over 8 years of experience. Specializing in creating comprehensive how-to guides, in-depth reviews, and engaging tech-related content.

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