Canvas Fingerprinting


#1

Why is Discourse /trying to/ fingerprinting my system?

https://browserleaks.com/canvas

Canvas is an HTML5 API which is used to draw graphics and animations on a web page via scripting in JavaScript.

Not necessarily a tracking method but can be used as such

But apart from this, canvas can be used as additional entropy in web-browser’s fingerprinting and used for online tracking purposes.

extracted text from screenshot
* Prevented a script on https://forum.manjaro.org from capturing the following 16px × 16px canvas (via getImageData):

* Prevented a script on https://forum.manjaro.org from capturing the following 16px × 16px canvas (via toDataURL):

![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAIElEQVQ4T2NkYGBgAmKyAeOoAQyjYcAwGgbAfDAM0gEAaygAMVluoggAAAAASUVORK5CYII=)

* Prevented a script on https://forum.manjaro.org from capturing the following 16px × 16px canvas (via getImageData):

* Prevented a script on https://forum.manjaro.org from capturing the following 16px × 16px canvas (via toDataURL):

![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAIElEQVQ4T2NkYGBgAmKyAeOoAQyjYcAwGgbAfDAM0gEAaygAMVluoggAAAAASUVORK5CYII=)

* Prevented a script on https://forum.manjaro.org from capturing the following 16px × 16px canvas (via getImageData):

* Prevented a script on https://forum.manjaro.org from capturing the following 16px × 16px canvas (via toDataURL):

![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAIElEQVQ4T2NkYGBgAmKyAeOoAQyjYcAwGgbAfDAM0gEAaygAMVluoggAAAAASUVORK5CYII=)

* Prevented a script on https://forum.manjaro.org from capturing the following 16px × 16px canvas (via getImageData):

* Prevented a script on https://forum.manjaro.org from capturing the following 16px × 16px canvas (via toDataURL):

![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAIElEQVQ4T2NkYGBgAmKyAeOoAQyjYcAwGgbAfDAM0gEAaygAMVluoggAAAAASUVORK5CYII=)

* Prevented a script on https://forum.manjaro.org from capturing the following 16px × 16px canvas (via getImageData):

* Prevented a script on https://forum.manjaro.org from capturing the following 16px × 16px canvas (via toDataURL):

#2

Found out about this a few days ago but I thought it was normal for a forum? :thinking:


#3

It has been on and off.

The first time it was noted was back in 2016.

It the dissappeared but returned - can’t remember exactly - 3 months time?


#4

I’ve never seen any notifications of Canvas fingerprinting on this forum until I re-installed Manjaro a few days ago. I logged in on Chromium and its Canvas blocker extension notified me of this. I’ve no idea when it started though.


#5

#6

Well - I thought it was something like that as I had been looking at the numbers it was trying to write. 1 2 3 etc.