WebAuthn: Large blob storage extension (largeBlob)

Category: Miscellaneous
Type: Chromium catches up
Status: Enabled by default (Chrome 113)
Intent stage: Prepare to ship

Breaking change: No
Enterprise impact: None
Chromium flag: enable-experimental-web-platform-features
Spec maturity: Published standard
Web Platform Tests: Yes

WPT details: This feature is completely tested in WPTs. Tests are automated via the webdriver virtual authenticator API. For browsers with no virtual authenticator support, they can still be run manually. https://wpt.fyi/results/webauthn -- see *large-blob* tests.

Summary

Adds support for the WebAuthn largeBlob [1] client authenticator extension. This extension allows relying parties to store opaque data associated to a credential. [1] https://w3c.github.io/webauthn/#sctn-large-blob-extension

Motivation

Storing information such as certificates associated to a WebAuthn credential.

Standards & signals

Specification: https://www.w3.org/TR/webauthn-3/#sctn-large-blob-extension
Firefox: No signal
Safari: Support
Web developers: Positive — I had a few developers reach out about availability, e.g. crbug.com/1282491.
Tracking bug: https://bugs.chromium.org/p/chromium/issues/detail?id=1114875

Ecosystem

Web Platform Tests: https://wpt.fyi/results/?q=webauthn
Chrome Platform Showcase: https://chrome-platform-showcase.paulkinlan-ea.deno.net/features
GenDN reference: https://gendn.paulkinlan-ea.deno.net/features
chrome.dev demos search: https://www.google.com/search?q=site%3Achrome.dev+WebAuthn%3A%20Large%20blob%20storage%20extension%20(largeBlob)
MDN Web Docs: https://developer.mozilla.org/en-US/search?q=WebAuthn%3A%20Large%20blob%20storage%20extension%20(largeBlob)
Baseline status: https://webstatus.dev/?q=WebAuthn%3A%20Large%20blob%20storage%20extension%20(largeBlob)

Samples: https://webauthn-large-blob.glitch.me/

Explainers: https://w3c.github.io/webauthn/#sctn-large-blob-extension

View on chromestatus.com