The Most Common Types of Two-Factor Authentication — And Which Are Safest
So, you’ve heard that two-factor authentication (2FA) can protect your accounts. That’s true. But not all 2FA methods are the same.
Some are easy to use. Some are more secure. And the best choice depends on what kind of account you’re protecting—and how much risk you’re comfortable with.
Let’s break down the three most common types of 2FA so you can make the right call.
One-Time Passcodes via Text or Email
How it works: After entering your password, you’re sent a code—usually six digits—by text message or email. You type in that code to finish logging in.
The advantages of a one-time password are that it’s simple and widely supported and it doesn’t require you to install anything.
The main disadvantage is that it is not the most secure method. If a hacker takes control of your phone number (via SIM card swap) or your email account, they can intercept the code.
Use it when:
- It’s the only option a site offers
- You’re protecting lower-risk accounts (like newsletters or online forums)
Authenticator Apps
How it works: You install an app like Google Authenticator, Microsoft Authenticator, or Duo on your phone. When you log in, the app gives you a fresh code every 30 seconds. Some apps also offer “push” notifications that let you approve or deny login attempts with one tap.
An authenticator app is more secure than text messages, because codes aren’t sent over the internet or phone network, and some apps show location/device details for each login attempt
However, you will need access to your phone to log in. These apps do require setup, but it’s typically an easy thing to do.
Use it when:
- You’re securing banking, email, or payment accounts
- The app offers login alerts or device approval
Security Keys
How it works: A physical device—like a USB key or wireless token—plugs into your computer or connects via Bluetooth or Near Field Communication (NFC). It confirms your identity when logging in.
Security keys are considered by many experts to be the most secure option, since they are immune to phishing and remote attacks. It is often easier for the user because there are no codes to type or manage.
The drawbacks are that you have to keep the key with you at all time and not all sites support this option.
Use it when:
- You manage sensitive accounts (finance, business tools, high-profile email)
- You want maximum protection
- You’re comfortable using a physical key
So…What’s Your Best Option?
Good: Text or email codes — better than nothing
Better: Authenticator apps — stronger and smarter
Best: Security keys — top-tier protection, especially for high-risk accounts The right choice depends on what you’re protecting.
For most people, an authenticator app strikes the best balance between ease and security.
