Why Push Notifications Are More Secure Than SMS

For years, SMS has been the go-to method for two-factor authentication. But as attacks have become more sophisticated, SMS-based 2FA has shown significant vulnerabilities. Here's why push notifications are a more secure alternative.

The Problem with SMS Authentication

SMS was never designed for security. It was designed for convenience—sending short text messages between phones. When we started using it for authentication, we inherited all of its weaknesses:

How Push Notifications Are Different

Push authentication takes a fundamentally different approach. Instead of sending a code through the phone network, it uses encrypted channels to your specific device.

Security Advantages of Push

1. Device Binding

Push notifications are sent to a specific device, not a phone number. The device is registered with cryptographic keys stored in the secure enclave—meaning even if someone knows your phone number, they can't receive your authentication requests.

2. End-to-End Encryption

Push notifications travel through encrypted channels (APNs for iOS, FCM for Android) with additional encryption layers. Unlike SMS, which travels through carrier networks in plain text, push notifications cannot be intercepted in transit.

3. Rich Context

When you receive a push authentication request, you see detailed information about the login attempt—the application, location, device, and time. This context helps you identify suspicious requests that a 6-digit code never could.

4. Phishing Resistance

There's no code to enter with push authentication. You simply approve or deny the request in the app. This eliminates the entire category of phishing attacks where users are tricked into entering codes on fake websites.

5. Biometric Confirmation

Push notifications can require biometric confirmation (Face ID, fingerprint) before approval. This adds another layer of security that SMS simply cannot provide.

But What About Offline Access?

One legitimate concern is that push notifications require an internet connection. That's why the best authentication apps (including AffirmID) provide TOTP codes as a backup. You get the security benefits of push when online, with offline fallback when needed.

Making the Switch

If you're still using SMS for two-factor authentication, consider switching to push-based authentication. Here's a quick comparison of what changes:

Conclusion

SMS-based 2FA is better than no 2FA, but it's time to move beyond it. Push notifications offer significantly stronger security without sacrificing convenience. In fact, they're often more convenient—one tap to approve beats typing a 6-digit code every time.

The security industry has been warning about SMS vulnerabilities for years. Major organizations like NIST have recommended against SMS for authentication. It's time we all listened.