nextAuth vs. FIDO

TECHNOLOGY

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Both nextAuth and FIDO aim to provide more secure and user-friendly user authentication. However, there are some differences in the approach. While nextAuth offers login, signing and secure sessions; FIDO only offers login functionality.

What is FIDO?

FIDO is an alliance of Internet Services, Component & Device Vendors, and Software Stacks. This alliance developed several open user authentication standards:

• Universal Authentication Framework (UAF) to provide a password-less experience.
• Universal Second Factor (U2F) to provide the second factor experience.
• FIDO 2:
  • W3C’s Web Authentication specification (WebAuthn), FIDO authentication webAPI integrated into browsers.
  • Client To Authenticator Protocol (CTAP), a device to device local protocol.

For the technical details on nextAuth, have a look at our technology page.

What are the similarities?

Both nextAuth and FIDO use public key cryptography. In the public key setting, there is a private key with corresponding public key. The party with the private key can authenticate to any party with the public key. The private key never leaves the nextAuth mobile component (FIDO authenticator). The public key is stored at the nextAuth server component (FIDO relying party). Social engineering to trick users into sharing their credentials will not work, since users don’t know these. The server also becomes less vulnerable to attacks. This is because it contains only public keys, which in itself cannot be used to authenticate with.

Both nextAuth and FIDO value the user’s privacy. To prevent tracking across servers, nextAuth and FIDO both generate new keys for each server.

How is nextAuth different?

When it comes to verifying the user, the nextAuth mobile component verifies the second factor (PIN or biometric**) online, with the help of the server. nextAuth does this in a zero-knowledge fashion, whereby the server does not learn anything about the PIN or biometric. Our patented True 2FA^TM approach excludes both local and remote attacks. In FIDO, user verification is done offline/locally by the FIDO authenticator, leaving it vulnerable to local attacks.

With nextAuth you can log in with your nextAuth mobile component on any webbrowser on any device, without having to configure this device. The device with the webbrowser/app that requests FIDO authentication needs to be running a FIDO authenticator (so-called platform authenticator, available on Android 7.0+ and Windows 10); or be connected to one over either USB, Bluetooth LTE or NFC. In other words, one cannot simply use his/her authenticator with any device without having to configure this device, insert a USB device, do a Bluetooth pairing, and/or switch on NFC.

Conclusion

This table compares nextAuth and FIDO with respect to the provided authentication functionality, attack vectors, and from the point of view of the user.

	nextAuth	FIDO
Functionality
– Login	Yes	Yes
– Signing (transactions/documents)	Yes	No
– Secure sessions (logout)	Yes	No
Attack vectors
– Social engineering	No	No
– Local (authenticator)	No	Yes
– Remote (server)	No	No
– Man In The Middle	No	Possible
User
– User unlinkability (privacy)	Yes	Yes
– User in control over session	Yes	No
– Zero user configuration	Yes	No

* In terms of authenticating the relying party, FIDO relies solely on the webbrowser/app to verify the TLS connection. Also note that while apps can (and should) implement certificate pinning, webbrowsers cannot.

** Biometrics are checked locally by the device the nextAuth mobile component is running on. If successful, a cryptographic key is unlocked. This key will then be verified with the nextAuth server component in a zero-knowledge fashion.