237 reviews
  • Thanks for your work! Please keep this in mind for the webextension: ghacks.net/2017/08/30/firefox-webextensions-may-identify-you-on-the-internet/
  • check
    HTML5 Canvas Protection ! Detected
    I'm aware of that. You could switch to "fake input"-mode which should not be detected. But this mode is less secure - fingerprinting over WebGL is possible with that. I know no good way to prevent this detection and keep the same level of privacy.
  • I really like this addon, but when I'm checking the results on Panopticlick I always see my windows size as a possible fingerprint. Any way to incorporate the screen size spoofing mechanism (only?) found in the addon Random Agent Spoofer (using script injection)?
    I think this could be done. But it would be out of the scope of this addon. Please open an issue for this request on github. There we can discuss the pro and cons.
  • Thanks.
  • Does a really good job at protecting against canvas fingerprinting attacks.
  • This makes privacy@firefox really great again :D thx
  • Its good but sometimes it breaks Facebook for me
  • Excellent. Does its job well.
  • Good plugin. It does a good job at randomizing canvas fingerprinting!!

    Only concern I have is that a new random value each time the canvas api is called could potentially be interpreted as unique by servers. Maybe have another option to create a new random value per session or new browser tab?

    Thanks for replying. Ah yes setting the random number generator to "persistent" does just what I want :)
    This is already implemented. You have to set the random number generator to "persistent".
  • Could do with the notification not encroaching on the real estate, but rather as a traditional notification which disappears.
    I understand why it was done this way (so that the site can be white-listed etc) but that's better accomplished by a toolbar button for those that want it.
    This si functionally much better than the other implementation only slightly marred.
    Since version 0.4.0 the notifications are different and use much less space.
  • Google is already able to identify your canvas as spoofed. Try to sign up for a Gmail account and you will see. Soon every tracking script online will be able too. An update is needed urgently!
    I always get to do the phone verification regardless of the addon.
  • The best canvas blocker I've tried.
  • The only thing I miss that fingerprint should not change within the same session, since two tries can easily reveal faking.
    Author mentioned that will take care of that too.
    Otherwise very very good job.
    Thank you
  • Great addon!

    It would be nice if there would be an option to automatically "whitelist" all sites on the Firefox cookie whitelist also :-)
  • Works with my most current version of FF and is compatible with all addons. A+
  • version 0.1.6 does not work with Mozilla 28.0
    please make a support for older versions
    Please file your issue/support request at https://github.com/kkapsner/CanvasBlocker/issues
  • thank you for your work! :)
  • Works better than expected, love it, finally no more tracking.
  • Works perfectly, does what it says! Rate this addon guys, there is no alternative to this one! Tested on panopticlick.org.

    Funktioniert wunderbar, alles zu vollster Zufriedenheit! Bewertet, damit sich das herumspricht! Getestet auf panopticlick.org.

    Funciona perfectamente. iDen cinco estrellas para que se sepa! Comprueben antes pero ahora mismo funciona muy bien en la pagina del eff.
  • Top notch, does what it says and solves the problem so that we no longer need disable Canvas. Extension needs more exposure, cannot believe I only just found it today.
  • great addon for mozilla browser
    PaleMoon has this feature implemented
    go to about:config and set "canvas.poisondata" to true. That's it!
  • Works great and blocks everything, running on Cyberfox 43.
  • Works well to block canvas fingerprinting.
    Unfortunately, I have to turn when reading PDFs. It doesn't really work with Firefox's PDF.js reader. It asks for permission every time I scroll to a new page.
    Also, I would like buttons to easily whitelist/blacklist a site without having to go into the options every time I want to do that.
    You might consider using the "ask only once" option or the faking mode. Latter has a nice notification system with some buttons and it is the main focus of the current development.
  • excellent countermeasure, validated on https://www.browserleaks.com/ and http://amiunique.org

    Hi kkapsner. Thanks. Version 0.1.3 indeed works on FF28. Maybe a FF bug caused it to offer updating to v0.2 after updating to FF28. Right now it only offers updating to 0.1.6, which is the latest that indicates (incorrectly?) FF28 as supported.

    And thanks for the extension! Now I just need something to block/control CSS transitions... :)

    And also thanks for pointing out, indirectly, that it's possible to download older versions from the Mozilla site :) (hidden at the bottom on the page, under the misleading title "Version Information", then "See complete version history". There's also more info there on supported FF versions per extension version).

    I'll use Github in the future (*sigh* another something that needs an account...).


    I'm on FF v28. The extension carried over from a previous FF version, and I also updated it after moving to v28. In FF's settings it's not disabled due to being "incompatible". Yet, in the FF addons site it says it's incompatible with v28.

    Assuming it's supposed to just block Canvas elements (which is what I'm after; fingerprinting is a secondary concern which I wasn't aware of before), I don't see any blocking action. The same was true also with the previous FF version I was using: no blocking. I was able to install it to begin with, so I think it should have worked, but maybe I'm missing something.
    Version 0.2.0 is definately not working with FF 28. Try an older version (I would start with 0.1.6 and then go backwards). If you realy want to have blocking of the canvas you have to set the blocking mode to "block all".

    PS: If you have further problems and want to contact me, please use github: https://github.com/kkapsner/CanvasBlocker/issues .