Firefox to show pop-up when sites use canvas drawing tracking

Browser Firefox will get a feature next year that will notify users if a site tries to track users through the canvas drawing. Users can then choose not to allow that. The feature comes from Firefox variant Tor Browser.

The “canvas tracking blocker” appeared in Bugzilla, Bleeping Computer noted. The feature is slated to be released in Firefox 58, a version set to be released in January of next year. The browser will initially pass worthless data to the site until the user allows tracking through the canvas drawing.

Using canvas tracking has been in vogue for a few years now. An invisible image is drawn via the canvas function of the browser, after which the drawn pixels are analyzed via the canvas API. Based on unique characteristics of the computer, for example the installed fonts, the time and browser data, a user can be tracked, just like with cookies.

The Tor Browser had the feature to prevent tracking via canvas drawings built-in for several years, but the feature has not been available in the regular version of Mozilla’s browser until now. Add-ons for browsers have previously appeared to prevent tracking via canvas drawings.