[tor-bugs] #22089 [Applications/Tor Browser]: Adding Decentraleyes to stop tracking by large CDNs (with slightly less traffic for exits) in the TBB

[Tor Bug Tracker & Wiki]

#22089: Adding Decentraleyes to stop tracking by large CDNs (with slightly less
traffic for exits) in the TBB
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     Reporter:  imageverif                |      Owner:  tbb-team
         Type:  enhancement               |     Status:  new
     Priority:  Medium                    |  Milestone:
    Component:  Applications/Tor Browser  |    Version:
     Severity:  Normal                    |   Keywords:  tbb-usability
Actual Points:                            |  Parent ID:
       Points:                            |   Reviewer:
      Sponsor:                            |
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 For those who don't know what it does: "Protects you against tracking
 through "free", centralized, content delivery. It prevents a lot of
 requests from reaching networks like Google Hosted Libraries, and serves
 local files to keep sites from breaking. Complements regular content
 blockers."[1]

 For example, according to W3Techs statistics, Google Hosted Libraries is
 used by 16.9% of all websites, that is a JavaScript content delivery
 network market share of 70.4%.[2] Decentraleyes works by blocking requests
 to that CDN and loading the Javascript libraries locally.

 That way not only some sites will load *slightly* faster (or faster for
 low-bandwidth clients) due to the resources being blocked and loaded
 locally  (which also means slightly less traffic needed for exits), but
 also will protect from tracking by those CDNs.[3]

 This addon doesn't clash with section 2.3. of the Tor Browser Design Doc
 with regards to ad-blockers as it isn't one.

 --

 [1] : https://addons.mozilla.org/en-US/firefox/addon/decentraleyes/
 [2] : https://w3techs.com/technologies/overview/content_delivery/all
 [3] : "The paper also makes me think about exit traffic patterns, and how
 to better protect people who use Tor for only a short period of time: many
 websites pull in resources from all over, especially resources from
 centralized ad sites. This risk (that it greatly speeds the rate at which
 an adversary watching a few exit points — or heck, a few ad sites — will
 be able to observe a given user's exit traffic)..." (replade ad sites with
 "free" CDNs ;)
 https://blog.torproject.org/blog/improving-tors-anonymity-changing-guard-
 parameters
 [4] : https://www.torproject.org/projects/torbrowser/design/ "As a general
 matter, we are also generally opposed to shipping an always-on Ad blocker
 with Tor Browser."

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/22089>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online