Making authentication even easier with FIDO2-based local user verification for Google Accounts

Written by Google Online Security Blog - - Aggregated on Monday August 12, 2019

Posted by Dongjing He, Software Engineer and Christiaan Brand, Product Manager
Passwords, combined with Google's automated protections, help secure billions of users around the world. But, new security technologies are surpassing passwords in terms of both strength and convenience. With this in mind, we are happy to announce that you can verify your identity by using your fingerprint or screen lock instead of a password when visiting certain Google services. The feature is available today on Pixel devices and coming to all Android 7+ devices over the next few days.

Simpler authentication experience when viewing your saved password for a website on passwords.google.com
These enhancements are built using the FIDO2 standards, W3C WebAuthn and FIDO CTAP, and are designed to provide simpler and more secure authentication experiences. They are a result of years of collaboration between Google and many other organizations in the FIDO Alliance and the W3C.
An important benefit of using FIDO2 versus interacting with the native fingerprint APIs on Android is that these biometric capabilities are now, for the first time, available on the web, allowing the same credentials be used by both native apps and web services. This means that a user only has to register their fingerprint with a service once and then the fingerprint will work for both the native application and the web service.
Note that your fingerprint is never sent to Google’s servers - it is securely stored on your device, and only a cryptographic proof that you’ve correctly scanned it is sent to Google’s servers. This is a fundamental part of the FIDO2 design.
Here is how it works
Google is using the FIDO2 capability on Android to register a platform-bound FIDO credential. We remember the credential for that specific Android device. Now, when the user visits a compatible service, such as passwords.google.com, we issue a WebAuthn “Get” call, passing in the credentialId that we got when creating the credential. The result is a valid FIDO2 signature.

High-level architecture of using fingerprint or screen lock on Android devices to verify a user’s identity without a password
Please follow the instructions below if you’d like to try it out.
Prerequisites
To try itYou can find more detailed instructions here.
For additional security
Remember, Google's automated defenses securely block the overwhelming majority of sign-in attempts even if an attacker has your username or password. Further, you can protect your accounts with two-step verification (2SV), including Titan Security Keys and Android phone’s built-in security key.
Both security keys and local user verification based on biometrics use the FIDO2 standards. However, these two protections address different use cases. Security keys are used for bootstrapping a new device as a second factor as part of 2SV in order to make sure it’s the right owner of the account accessing it. Local user verification based on biometrics comes after bootstrapping a device and can be used for re-authentication during step-up flows to verify the identity of the already signed-in user.
What’s next
This new capability marks another step on our journey to making authentication safer and easier for everyone to use. As we continue to embrace the FIDO2 standard, you will start seeing more places where local alternatives to passwords are accepted as an authentication mechanism for Google and Google Cloud services. Check out this presentation to get an early glimpse of the use cases that we are working to enable next.

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