What is CanvasBlocker?
This add-on allows users to prevent websites from using the Javascript <canvas> API to fingerprint them. Users can choose to block the <canvas> API entirely on some or all websites (which may break some websites) or just block or fake its fingerprinting-friendly readout API. More information on <canvas> fingerprinting can be found at http://www.browserleaks.com/canvas.
The different block modes are:
• block readout API: All websites not on the white list or black list can use the <canvas> API to display something on the page, but the readout API is not allowed to return values to the website.
• fake readout API: Canvas Blocker's default setting, and my favorite! All websites not on the white list or black list can use the <canvas> API to display something on the page, but the readout API is forced to return a new random value each time it is called.
• fake at input: on display of text the drawn pixels get modified slightly. This makes the detection of the add-on harder but is less secure. On WebGL-canvas the behaviour is identical to "fake readout API".
• ask for readout API permission: All websites not on the white list or black list can use the <canvas> API to display something on the page, but the user will be asked if the website should be allowed to use the readout API each time it is called.
• block everything: Ignore all lists and block the <canvas> API on all websites.
• allow only white list: Only websites in the white list are allowed to use the <canvas> API.
• ask for permission: If a website is not listed on the white list or black list, the user will be asked if the website should be allowed to use the <canvas> API each time it is called.
• block only black list: Block the <canvas> API only for websites on the black list.
• allow everything: Ignore all lists and allow the <canvas> API on all websites.
Protected "fingerprinting" APIs:
• canvas 2d
• webGL
• audio
• history
• window (disabled by default)
• DOMRect
CanvasBlocker information
Germany
EU
Comments and Reviews
Not a simple CanvasBlocker... like mosts
Protected "fingerprinting" APIs:
canvas 2d webGL audio history window (disabled by default) DOMRect
Eliminates a way for websites to track your web browsing activity
I just downloaded it, and I have not had time to adequately test it. So far, so good, with preliminary tests. I have been using Canvas Defender for years, and I love it! Canvas defender no longer works on Chrome/ Chromium based browsers. Because of that, I uninstalled my Chrome/Chromium Browsers except Epic Privacy Browser, which I love. In addition I am using the latest Firefox, and Firefox Nightly I am still using Canvas Defender on Firefox. On Firefox Nightly, I noticed a strange hashtag notice when I changed it. I change the hashtag, manually before closing the browser, each time, instead of using auto-change mode. The notification box seemed to assing an id/hashtag value to the Nightly browser that stayed the same, regardless of how many times that I repeated the process many times and although the regular hash value changed every time, the id for "Nightly" stayed the same. I am concerned about the compatibility of Canvas Defender with Nightly. It still does NOT do this with regular Firefox! Because of this, I downloaded CanvasBlocker to use in the "false mode". When I have time, I will do extensive testing for both Canvas Defender and CanvasBlocker on Nightly and let you know the results. -E