2FA (Two Factor Authentication) or MFA, (Multi-Factor Authentication) should be used on every account where that is an option in order to add security to the account, here we will discuss the more common options and why some choices of 2FA are better than others.
We can divide 2FA types into a handful of categories:
Software Tokens (Authy, Authenticator, Aegis, SMS, email confirmation/code, TOTP – Temporary One Time Passcodes)
SMS (Text Message link or code)
TOTP (Temporary One Time Passwords)
Hardware Tokens (Yubikey)
Recovery Codes (Seed Phrases)
Software Tokens have a range of methods, SMS is considered poor for privacy as this links your phone to your computer. While decreasing, another risk of SMS for 2FA is something called a SIM swap attack where an attacker gains access to your account through the hijacking of your SIM information and having the 2FA code sent to their phone in order to login or reset your account. This presents a serious security risk to your account. App generated codes are a much better choice to generate a TOTP, my top choices for these are:
Authenticator for your computer (Flatpak from Flathub on Linux) or
Authy for your computer, also available on Flathub, and
Aegis for your mobile device. (You can mix and match these, you don’t have to use only one; example, you could use Authy for your X account on your computer, and also use Aegis on your phone to unlock the same X account) Use F-Droid to download to your Android device.
If App Generated codes or Hardware Tokens are not able to be used, avoid SMS and use email TOTP (you login to the site, and are required to grab a TOTP from an email sent to you and paste it into the site to gain access, usually this is a 6 digit number)
Hardware Tokens are extremely robust for hardening your accounts, but not all accounts accept 2FA Hardware Tokens. This is a physical device such as a YubiKey that is required to be physically present in order to gain access to the account after giving your username/password. This ensures that even if someone steals or guesses your account credentials, they have to have access to the physical device in order to be successful at logging in. This means you also must have this present to access your stuff, I carry and use one every day.
They work like this- you login to say, your bank, something you want secured with the hardware token. You enter your username and password, and because you set up 2FA using the hardware token, you are challenged before entering the account. Simply plug in the hardware token (a YubiKey for example) to a USB port and when challenged at login, simply tap the Yubikey and it will auto-populate a key to grant access.
One YubiKey can get you into multiple accounts, not just one, and it is strongly recommended to always buy 2 or more of these in order to have a backup. You can clone up to 5 YubiKeys for a single account. These are fairly easy to setup with your accounts, look for 2FA or MFA under your settings menu in your account profile to pair the key with the account. There are other hardware tokens other than YubiKey also, and it’s possible to make your own using a USB drive, but I find YubiKey to be a much more reliable solution than anything else. Learn the technical aspect of a YubiKey here.
Finally we have Recovery Codes, usually referred to as ‘Seed Phrases’ as an emergency recovery method should your physical Hardware Token be lost or destroyed. Most are 12 word, but you can see in this example below that 24 generated words are used. Anytime you use hardware tokens, it is your responsibility to have your recovery code saved in the event you lose your physical token, this helps guard against getting permanently locked out of your account.