Canvas cookies are "machine fingerprints" using HTML5 canvas, which are not 100% reliable, but are very persistent. They are used to track visitors for marketing or profiling. They don't store user data per-se, but if used in conjunction with a site that does collect your data, you can be personally tracked by any sites which share this data.

Clearing local cache or history, entering "private" mode, and most other things used to gain privacy on the internet will not work against this tracking mechanism.

Is there any Chrome add-on or module that does provide a little privacy against this cookie mechanism?

2 Answers 2


There is Privacy Badger - currently in Beta testing but available for download from The Electronic Frontier Foundation - it is a plugin for both Chrome & Firefox.

From wikipedia:

"Privacy Badger blocks Canvas Fingerprinting which exploits the HTML 5 Canvas element. This online digital tracking technology allows websites to uniquely identify and track visitors without the use of browser cookies or other similar means."


The CanvasFingerprintBlock Chrome extension patches toDataURL() and getImageData() so that they return data from a blank canvas, thus rendering the fingerprint useless.

Disclaimer: I am the author of this extension.

  • Has negative reviews in Chrome store, people complain that it doesn't work. Feb 26, 2016 at 12:18
  • Thanks @DeerHunter. Yes, the extension was not handling canvas elements inside sandboxed iframe elements properly. This has now been fixed in the latest release (version 1.2).
    – dwardu
    Feb 27, 2016 at 23:34

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