In 2024 alone, over 1.5 billion user records were exposed through data breaches, according to the Identity Theft Resource Center’s annual report.

Passwords alone are no longer sufficient protection; they’re guessed, phished, reused across sites, and leaked in database breaches on a daily basis. Two-factor authentication (2FA) adds a second verification layer that makes compromised passwords nearly useless to attackers.

Microsoft’s security research team found that accounts with 2FA enabled block 99.9% of automated attacks. That’s not a marginal improvement; it’s the difference between an open door and a locked vault.

Here’s what 2FA is, how the different types compare, and how to set it up on your most important accounts.

How Two-Factor Authentication Works

Authentication factors fall into three categories:

• something you know (a password),
• something you have (a phone, a hardware key), and
• something you are (a fingerprint, face scan).

Single-factor authentication uses only a password.

Two-factor authentication requires both a password and a second factor from a different category; proving your identity through two independent methods.

Even if an attacker obtains your password, they can’t access your account without also possessing your physical device or biometric data. This dramatically raises the difficulty, cost, and effort required for a successful attack.

Type 1: SMS Verification Codes

The most common form of 2FA sends a one-time code via text message to your registered phone number. After entering your password, you receive a 6-digit code that expires within minutes.

Pros: requires no additional apps or hardware, works on any phone that receives texts, and is better than no 2FA at all.

Cons: SMS messages can be intercepted through SIM swapping attacks (where an attacker convinces your carrier to transfer your number to their SIM card).

The National Institute of Standards and Technology (NIST) has flagged SMS as the weakest 2FA method and recommends alternatives where possible.

Type 2: Authenticator Apps

Authenticator apps (Google Authenticator, Microsoft Authenticator, Authy, and 1Password) generate time-based one-time passwords (TOTP) that refresh every 30 seconds directly on your device.

Because the codes are generated locally and never transmitted over a network, they’re immune to SIM swapping and SMS interception.

Pros: significantly more secure than SMS, works without cellular service, and most authenticator apps are free.

Cons: losing your phone without backup codes can lock you out (always save your backup recovery codes when setting up 2FA).

Authy offers encrypted cloud backup of your 2FA tokens, making device transitions simpler than Google Authenticator’s manual transfer process.

Type 3: Hardware Security Keys

Physical security keys like YubiKey and Google Titan are USB or NFC devices that must be physically present during login.

You insert the key (or tap it on your phone) as your second factor. They use the FIDO2/WebAuthn protocol, which cryptographically verifies both the user and the website, making phishing attacks virtually impossible because the key won’t authenticate on a fake site.

Pros: the most secure 2FA method available, phishing-resistant, works offline, and extremely fast (tap and go).

Cons: physical keys cost $25–$50 each, and you should buy two (one primary, one backup stored securely).

Google reported that after requiring hardware keys for all 85,000+ employees in 2017, successful phishing attacks dropped to zero.

Step-by-Step: Enable 2FA on Your Google Account

1. Navigate to myaccount.google.com and sign in.
2. Click “Security” in the left panel.
3. Under “How you sign in to Google,” click “2-Step Verification” and then “Get started.”
4. Google will walk you through adding your phone number for SMS codes.
5. Once SMS is active, scroll to “Authenticator app” and click “Set up.”
6. Open your authenticator app, scan the QR code Google displays, and enter the verification code the app generates.

After setup, Google will present backup codes — ten single-use codes for emergency access if you lose your phone. Save these somewhere secure: a password manager, a printed sheet in a safe, or an encrypted file.

Losing both your phone and these codes means a lengthy account recovery process.

Which Accounts to Prioritize

Enable 2FA on accounts in this order of priority:

• email (your email is the master key; password resets for every other service route through it)
• financial accounts (banking, investments, payment services like PayPal)
• cloud storage (Google Drive, iCloud, Dropbox; these often contain sensitive documents)
• social media (to prevent impersonation and data harvesting), and
• work accounts (especially those with access to company systems or customer data).

Bottom Line

Any form of 2FA is dramatically better than none. If you do nothing else after reading this, enable authenticator-based 2FA on your primary email account today; it takes under 5 minutes and is the single most impactful security improvement most people can make.

Upgrade to hardware keys for accounts that protect your livelihood or contain irreplaceable data.