U2F vs. WebAuthn: What’s the difference and why should you care? The main difference between U2F and WebAuthn is that U2F works as a second factor to strengthen the existing password-based authentication, while WebAuthn can work both as a second factor and as a single factor, thus supporting passwordless authentication scenarios. U2F is an open authentication standard developed by the FIDO Alliance that uses public-key cryptography to provide robust Multi-Factor Authentication (MFA). U2F requires users to insert a special USB device, such as a U2F key, into their computer and press a button to allow the site to securely identify them. WebAuthn is the latest version of the FIDO Alliance’s open authentication standard, designed to bring strong 2FA to the web, and it is based on the W3C’s Web Authentication API. It provides secure authentication across web-based platforms and supports biometrics, passwords, and USB keys.
U2F Overview
Universal 2nd Factor (U2F) is an open authentication standard developed by the FIDO Alliance that uses public-key cryptography to provide strong two-factor authentication (2FA) for websites, cloud services, and mobile applications. U2F requires users to insert a special USB device, such as a U2F key, into their computer and press a button to allow the site to securely identify them. This creates an additional layer of security on top of traditional username/password authentication.
U2F works by creating a cryptographic signature which is used to authenticate a user. The signature is generated using a combination of a private key stored on the U2F device, the website’s public key, and a random challenge string. When the user presses the button on the device, the website will receive the signature verifying their identity. This prevents malicious actors from intercepting and using the user’s credentials for fraudulent purposes, as the signature cannot be reproduced from the user and the website’s public information alone. This provides a strong layer of protection. Even if a malicious actor knows the user’s username and password, they still need to have the U2F device in their possession to complete the authentication process.
WebAuthn Overview
WebAuthn is the latest version of the FIDO Alliance’s open authentication standard. It is an effort to bring strong 2FA to the web and is based on the W3C’s Web Authentication API, which is supported by many common web browsers. WebAuthn leverages public-key cryptography to create a unique digital signature that provides secure authentication across web-based platforms. It also allows users to use biometrics such as fingerprints instead of physical tokens for authentication.
WebAuthn builds on the same strong two-factor authentication foundation as U2F. However, it has been designed to better fit within the web environment. It is browser-based and uses a different type of key than was previously employed by U2F. In technical terms, WebAuthn uses elliptic curve public/private key pairs for authentication. This type of key is more secure than the traditional U2F key, as malicious actors cannot easily guess it, and it is much harder to reproduce.
Further, WebAuthn does not require users to insert a physical token, such as a U2F key, into their computer. Instead, users can use biometrics such as fingerprints, facial recognition, or eye scans to authenticate.
Moreover, WebAuthn provides support for public key credential extensions, including the ability to store multiple public key credentials on a device. This enables users to authenticate with different sites or services without inserting multiple U2F devices. Finally, WebAuthn also supports cryptographic attestation, which allows for improved authentication for websites or applications that are set up to verify user data properly.
U2F vs. WebAuthn: What’s the Difference?
| U2F | WebAuthn | |
| Definition | U2F (Universal 2nd Factor) is a two-factor authentication standard developed and maintained by the FIDO Alliance. It is designed to protect users against common phishing and man-in-the-middle attacks. | The Worldwide Web Consortium (W3C) standard for two-factor authentication that replaces the traditional username-password combination with a more secure alternative. |
| Requirements | U2F requires hardware — typically a physical USB key or comparable device. | WebAuthn does not require hardware, instead using public key cryptography and platform-specific authenticators, such as a Trusted Platform Module (TPM) in a laptop or biometric authentication built into a secure enclave in a smartphone. |
| Clients | U2F is limited in the number of clients supporting it because it requires hardware such as physical USB keys or comparable devices. | WebAuthn has broader client support — any WebAuthn-enabled browser can use the service. |
| Security | U2F is highly secure due to its use of public key cryptography. | WebAuthn relies on the same public key cryptography as U2F for its security and oasts additional security measures. |
Comparison of U2F and WebAuthn
U2F and WebAuthn are similar in using public-key cryptography for authentication. Still, there are a few key differences to consider:
- Development and Licensing. The FIDO Alliance, which includes Google, Yubico, and other members, developed U2F, while the W3C developed WebAuthn. U2F requires licensing and certification, while WebAuthn is an open standard that anyone can implement and use.
- Hardware Requirements. U2F requires users to insert a special USB device known as a U2F key into their computer to gain access to a site. On the other hand, WebAuthn does not require any special hardware—users can use their existing devices, such as biometric scanners or mobile devices, to gain access.
- Device Compatibility. U2F can only authenticate users on websites, while WebAuthn can authenticate users across multiple types of devices, such as mobile devices, desktop computers, and IoT devices.
- FIDO2 Support. WebAuthn is compatible with any hardware device that supports the FIDO2 standard, such as USB keys, smartphones, smartwatches, or laptops. In contrast, U2F is only compatible with devices that support the U2F protocol, such as YubiKeys or Google Titan keys.
- Backward Compatibility. WebAuthn also has the advantage of being backward compatible with U2F. This means that most websites and services that use U2F will be able to support WebAuthn, with only minor changes or adjustments.
- Authentication Factors. U2F only supports two-factor authentication (2FA), which means users need to use a device and a password. WebAuthn supports multi-factor authentication (MFA), which means users can use more than one factor to authenticate themselves, such as a device and a biometric factor. WebAuthn also allows for passwordless authentication, which eliminates the need for passwords altogether.
- Phishing Protection. Both WebAuthn and U2F provide strong protection against phishing attacks or compromised credentials by using public-key cryptography and origin verification. However, WebAuthn provides stronger protection due to its support for MFA and passwordless authentication.
- New Features. WebAuthn also introduces several new features not available in U2F. One of these features is the ability to identify the user’s device more securely. Another is privacy protections that prevent attackers from accessing the user’s data and history.
Advantages of U2F
U2F provides an extra layer of security on top of traditional username/password authentication. The need to insert a physical USB device makes hijacking user accounts much more difficult. This makes it well-suited for environments where users need to securely access multiple services on the same device, such as corporate networks.
Advantages of WebAuthn
WebAuthn provides a more user-friendly experience compared to U2F. Unlike U2F, it does not require any special hardware, making it more accessible and easier to use. WebAuthn also has better compatibility across multiple platforms, such as mobile and web browsers, and can support a variety of authentication options, such as biometrics, NFC, and USB keys.
How to Implement WebAuthn
Implementing WebAuthn on a website requires the use of a FIDO2 credential server. This is an online service that provides authentication services to websites and applications. Developers can use this service to create custom authentication flows that integrate with their website or application. Once the FIDO2 credential server is set up, websites or applications must redirect the user to the server’s authentication page to authenticate them.
WebAuthn vs. U2F: Which One Should You Use?
The answer to this question depends on your needs and preferences. U2F is a simple and easy-to-use solution that provides strong security for your online accounts. However, U2F requires you to use specific hardware devices that may not be available or convenient for you.
WebAuthn is a more advanced and flexible solution that provides stronger security and a better user experience for your online accounts. Many websites and services support WebAuthn, an open standard that allows you to use any hardware device that supports the FIDO2 standard, as well as biometric factors or passwordless authentication.
Ultimately, both WebAuthn and U2F are good solutions for enhancing your online security and reducing your reliance on passwords. However, WebAuthn is the future of web authentication. It offers more benefits and features than U2F, such as stronger protection, better user experience, more flexibility, and more compatibility. Therefore, we recommend you to use WebAuthn whenever possible, and U2F as a backup option. Therefore, we recommend you to use WebAuthn whenever possible, and U2F as a backup option.
How Rublon MFA Can Help You Secure Your Accounts with U2F and WebAuthn
If you are looking for a simple and effective way to protect your online accounts from phishing, credential theft, and account takeover, you might want to consider using Rublon MFA.
Rublon supports FIDO security keys that use U2F or WebAuthn during authentication.
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Summarizing U2F vs. WebAuthn
When comparing U2F vs. WebAuthn, there are a few key differences to consider. U2F requires a hardware device like a USB key, whereas WebAuthn does not and has better compatibility with multiple platforms. U2F provides an extra layer of security, while WebAuthn also delivers a more user-friendly experience. Compared to traditional methods, both standards offer enhanced security measures and a FIDO2 credential server can implement them both. Nevertheless, WebAuthn is the better choice of the two.
