After January, Firefox users will be able to refuse websites’ requests that can lead to browser fingerprinting.
Browser fingerprinting is an alternative website analytics experts use to cookies as a way to identify users and track their online behavior.
In Firefox 58, which is scheduled to release in January, Mozilla will address the issue of “canvas fingerprinting,” which works by exploiting the browser’s HTML5 canvas element.
The technique works when a user visits a website that sends a request to his browser to render hidden text or graphic on a hidden canvas element. The result is extracted, and a hash of it becomes the fingerprint of the browser.
This fingerprint ends up shared among advertising partners, and used to detect when that user visits affiliated websites. In this way, a profile of the user’s browsing habits can end up created, and used to target advertising.
Canvas fingerprinting works because each browser and the system on which it is installed has a specific hardware and software configuration, meaning the fulfilment of the site’s request will result in different renders and, therefore, different and possibly unique fingerprints.
Some browser fingerprinting attempts can end up halted by using add-ons like Privacy Badger or DoNotTrackMe in conjunction with ad blocking lists.
Firefox will become the first of the major browsers to do something about this online tracking technique.