[tbb-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 blackhole at torproject.org
Thu Apr 27 20:57:24 UTC 2017

#22089: Adding Decentraleyes to stop tracking by large CDNs (with slightly less
traffic for exits) in the TBB
     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:                            |
 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

 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 ;)
 [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."

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

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