Intent to Prototype: Noising canvas readbacks in Incognito

[Chromestatus]

Contact emails

t...@chromium.org, antonio...@chromium.org, john...@google.com, riz...@google.com

Explainer

https://github.com/explainers-by-googlers/canvas-noise-on-readbacks

Specification

None

Summary

The canvas APIs allow websites to draw shapes and forms on a canvas and read back the rendered image. However, the browser's rendering process leaks details about the GPU's properties. The goal of adding noise to canvas readbacks is to prevent scripts from easily obtaining identifying information that can be used to re-identify a browser across contexts. The noise that is added to the pixels is deterministic for a given canvas, and changes based on the site of the embedding document. With this feature noise would only be added to canvas readbacks for users in Incognito mode.

Blink component

Blink>Canvas

Motivation

The specific way in which shapes and forms are rendered on the GPU expose information about the characteristics of that GPU. By adding noise to the pixel values upon readback, easily obtaining identifying information that can be used to re-identify a browser across contexts is no longer feasible.

Initial public proposal

https://github.com/explainers-by-googlers/canvas-noise-on-readbacks

TAG review

None

TAG review status

Pending

Risks

Interoperability and Compatibility

None

Gecko: Shipped/Shipping (https://bugzilla.mozilla.org/show_bug.cgi?id=1816189)

WebKit: Shipped/Shipping (https://bugs.webkit.org/show_bug.cgi?id=243555)

Web developers: No signals

Other signals:

WebView application risks

Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?

None

Debuggability

None

Is this feature fully tested by web-platform-tests?

No

Flag name on about://flags

None

Finch feature name

None

Non-finch justification

None

Requires code in //chrome?

False

Tracking bug

https://g-issues.chromium.org/issues/399653248

Launch bug

https://launch.corp.google.com/launch/4386318

Estimated milestones

No milestones specified

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5589949602332672?gate=5107144812396544

This intent message was generated by Chrome Platform Status.

[PhistucK]

Will it allow detection of incognito mode, though? Hopefully not...

☆PhistucK

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