What is 2-factor authentication? How it works and what benefits you should know

What is 2-factor authentication and why is it considered a security standard for online accounts? This is an additional authentication method in addition to passwords, helping to protect personal information and digital assets from the risk of unauthorized access. Thanks to 2-factor authentication, even if the password is exposed, it is difficult for bad guys to break into the account, providing maximum peace of mind when using online services.

1. Overview of 2-factor authentication (2FA)

1.1. Concept

2-factor authentication (2FA) is a method of authenticating users through two different layers of security, instead of relying solely on a password as is traditional. These two layers often belong to different types of authentication factors, including:

• Knowledge factor: Something the user knows like a password or PIN.
• Possession factor: Things users own like phones, hardware tokens, smart cards.
• Inherence factor: User biological characteristics such as fingerprints, face, voice.

For example: When logging into an email account, customers need to enter a password (knowledge factor) and an OTP code sent to their phone (ownership factor). This is a typical mechanism of 2-factor authentication, ensuring that even if the password is exposed, it is difficult for bad guys to illegally access the account.

The main goals of 2-factor authentication include:

• Enhanced security: Prevent unauthorized access even if password is exposed.
• Protect sensitive data: Reduce the risk of theft of personal information, bank accounts, emails, social networks.
• Increase authenticity: Confirm that the person logging in is the legitimate owner of the account.

Two-factor authentication helps increase account security.

1.2. How it works

2-factor authentication works on the principle of two different factors, ensuring that account access is not based on a password alone. A typical process includes the following steps:

• Step 1 - Enter basic login information: The user enters a username and password (knowledge element).
• Step 2 - Second Factor Authentication: The system requires an additional element, for example:
• OTP (One-Time Password) code sent via SMS, email or authentication application.
• Hardware token generates random code.
• Biometric authentication such as fingerprint or face.
• Step 3 - Check and allow access: If the second factor is valid, the user is granted access to the account. If invalid, access is denied.

1.3. Advantages

Using 2-factor authentication brings many outstanding benefits:

• Enhanced security: Reduces the risk of intrusion even if the password is stolen.
• Protect important data: Prevent unauthorized access to personal information, bank accounts, email, and other online services.
• Reduce the risk of fraud: Limit the impact of phishing attacks because the bad guys don't have a second factor.
• High reliability: Combines two different authentication factors, which helps to accurately verify the user.
• Flexibility: Multiple 2FA methods (SMS, email, authenticator apps, biometrics) give users the choice they need.

2. Types of 2-factor authentication

2.1. Authentication by SMS (OTP)

SMS authentication uses an OTP (One-Time Password) code sent directly to the user's registered phone number. This code is usually short-lived, can only be used once, and is sent immediately after the user enters their username and password. Upon receiving the OTP code, the user simply enters the code into the system to complete the login process.

This form is quite convenient, easy to use and supported by many online services. However, it also has some limitations, such as the risk of theft through SIM swapping or being completely dependent on the phone signal, so it is not available when there is no signal.

Authentication by OTP sent to phone is a very popular form.

2.2. Authentication via phone call

Phone call authentication is a method in which the system makes a direct call to the registered phone number to announce the authentication code or ask the user to press a key to confirm. After entering the password, the user listens to the call and follows the instructions, such as entering the spoken code or pressing a confirmation key, to complete the login.

This method of calling is very convenient for people who are not tech-savvy and can be used when SMS is not available, such as in areas with poor signal. However, it has the disadvantage of being expensive if the call is international, less convenient than SMS or app authentication and persistence risk of call spoofing if not checked carefully.

2.3. Email verification

Email authentication is a method in which the system sends an authentication code or confirmation link to the user's registered email address after they enter their username and password. The user needs to open the email, get the OTP code or click on the link to complete the login process.

This method is quite convenient, especially when the user does not have a phone nearby or does not want to receive SMS, while still ensuring a basic level of security for the account. However, the downside is that it depends on email access. If the email account is hacked or access is lost, the security of this method will be affected.

2.4. QR Authentication

QR authentication is a form of 2-factor security commonly used in mobile applications or online services, in which the user scans a QR code provided by the system using an authentication application, such as Google Authenticator or Microsoft Authenticator. After scanning the code, the application will automatically generate an OTP code that changes continuously, and the user enters this code to authenticate the login.

Many websites use QR scanning technology to increase account authenticity.

Using QR is both convenient and secure because the OTP code is generated directly on the user's device and does not depend on SMS or email. However, users need to install an authentication application and keep the device safe. If the phone is lost or the device is damaged, logging in will be difficult.

2.5. Authentication by digital signature

Digital signature authentication is a two-factor authentication method in which users use a digital signature issued by a certification authority to confirm their identity. When logging in, the system requires the user to sign digitally on a device, such as a USB token or smart card, to authenticate the information.

This authentication method ensures a high level of security thanks to its ability to verify identity accurately and prevent tampering. It is often used in online banking transactions, government agencies or important systems that require maximum security. The disadvantages are high implementation costs, specialized equipment requirements and a more complex process than conventional methods.

2.6. Biometric authentication

Biometric authentication uses a user's unique biological characteristics such as fingerprint, face, iris, voice, or digital signature to verify identity. After entering a password, the user needs to provide biological characteristics to complete the login.

This method is both convenient and highly secure, as biological characteristics are difficult to copy or steal. It is often applied to smartphones, laptops or systems that require high security. However, the disadvantages are that the equipment cost is relatively high, regular maintenance is required and there is still a risk if biometric data is leaked or copied illegally.

Biometric authentication is a highly secure method

3. 4+ Applications of 2-layer security

3.1. Protect your bank account

Two-factor authentication enhances the security of online banking accounts by requiring an additional factor in addition to a password, usually a One-Time Password (OTP) via SMS, email, or authenticator app. This helps prevent unauthorized access even if a password is compromised, while minimizing the risk of fraudulent transactions.

According to Circular 41/2025/TT-NHNN, effective from date 01/01/2026, customers opening e-wallets are required to verify biometric information when opening e-wallets. In addition, according to Circular 17/2024/TT-NHNN, from January 1, 2025, customers are required to verify biometric authentication for all money transfers.

3.2. Protect your social media accounts

2-factor authentication enhances the security of social media accounts by requiring an additional layer of authentication in addition to a password, such as an OTP code, an authenticator app, or email confirmation. This prevents unauthorized access, protects personal information, photos, messages, and control of a personal page or fanpage.

Popular social networks that apply 2FA include Facebook, Instagram, Twitter (X), TikTok, and LinkedIn. These platforms offer multiple authentication methods for users to choose from according to their needs and devices.

Most social networking sites have two-factor authentication.

3.3. Protecting e-wallets

2-factor authentication enhances the security of e-wallets by requiring an additional authentication factor in addition to a password, usually an OTP via SMS, email, or an Authenticator app. This prevents unauthorized access, protecting balances, transaction history, and important payment information.

Some popular e-wallets that apply 2FA include MoMo, ZaloPay, VNPay, ShopeePay.

3.4. Protection of transactions on financial exchanges

2-factor authentication helps protect transactions on financial exchanges by requiring an additional layer of authentication beyond a password, such as OTP or app authentication, before making a purchase, sale, or transfer order. This reduces the risk of being hacked, protecting users' assets and transaction information.

Financial, stock and cryptocurrency exchanges such as Remitano, Binance, Upbit, eToro all apply 2-factor authentication to increase user safety.

4. 4+ Notes when using 2-factor authentication

To maximize the effectiveness of 2-factor authentication and avoid potential risks, users need to note the following important points:

• Backup code is recommended: Backup codes help you still access your account if you lose your authentication device or phone. It's important to keep them in a safe place.
• Limit the use of SMS authentication if possible: This method is susceptible to SIM spoofing (SIM swap), so if possible, prefer Authenticator apps or more secure authentication methods.
• Do not share the OTP code with anyone: OTP code is the only information that helps authenticate identity, sharing with others will reduce security effectiveness.
• Update the Authenticator app periodically: Updating the application helps patch security holes, ensuring that the OTP codes generated remain safe and valid.

Combining all of the above measures will help 2-factor authentication work effectively, reduce the risk of being attacked and maximize protection for your personal account.

Open an account at SeABank today to experience modern banking services with high security thanks to 2-factor authentication technology. The registration process is quick and convenient, with just a few simple steps on the app or website. All your information and transactions are optimally protected, helping you to manage your finances with peace of mind anytime, anywhere!

SeABank is currently using 2-layer authentication and applying many new security technologies for customers on the SeAMobile application.

5. Frequently Asked Questions

1. Are 2-factor authentication and two-factor authentication different?
No, these two terms refer to the same authentication method (2FA).

2. What if I lose the phone containing the Authenticator app?
You can use a backup code or contact support to restore access.

3. Is 2-factor authentication mandatory?
Not required, but highly recommended on all major platforms.

4. Can 2-factor authentication be enabled for multiple accounts at the same time?
Yes, such applicationGoogle Authenticator supports saving multiple accounts in the same application. Users are advised to enable 2-factor authentication for accounts containing sensitive information such as personal information, banking transactions,...

Thus, understanding clearly What is 2-factor authentication and applying it correctly will help you increase the security of your accounts, data and online transactions. Be proactive in activating 2-layer security on all services you use to protect your personal information and experience the internet more safely and conveniently every day. Besides, when experiencing the service at SeABank, customers will receive satisfaction becauseAll information and transactions are secured to the highest standards of SeABank.

If you want to learn more about SeABank's card products, you can contact the nearest transaction point or call Hotline 1900 555 587 or visit the website www.seabank.com.vn for more details.