Tor activists announced the start of the FUSION project (translated as "merge", but at the same time represents the abbreviation of Firefox USIng Onions). This is a project to integrate Tor Browser features directly into Firefox.

As you know, Tor Browser is built on the basis of Firefox ESR with a bunch of patches specific to Tor. It is not very convenient for anonymous web browser developers to spend time relocating these patches from one repository to another. Therefore, a few years ago, together with Mozilla, the Uplift project was organized, which included the automatic inclusion of Tor Browser patches into the Firefox code base. Over the past year and a half, new information security features have been simultaneously introduced into the Tor Browser and Firefox. This is element isolation (First-Party Isolation, setting privacy.firstparty.isolate in Firefox 52+, it’s also part of the Cross-Origin Identifier Unlinkable key system that provides anonymity in the Tor Browser), the anti-fingerprint system, including fingerprinting using the set fonts , counteraction to HTML5 canvas fingerprinting , new privacy.resistFingerprinting setting in Firefox 59+, etc.

Now the time has come for the next stage: tighter integration and eventually a complete merge of Firefox and Tor Browser.

Fusion project goals

• Further resistance to fingerprinting . Protection against fingerprinting on fonts works successfully, but is disabled by default in Firefox because it breaks some sites. The developers set the task to make the protection more user-friendly, improve compatibility with the sites and continue to track new fingerprinting methods. They will be blocked in Tor Browser and Firefox at the same time.
• Implementing a framework to bypass the proxy .
• Explore the best way to integrate Tor proxies into Firefox . The Tor client can be implemented as a separate process or library (this issue is currently under discussion).
• A truly private surfing mode in Firefox, which will include features for isolating elements, counteracting fingerprinting and Tor proxies. Currently, Tor Browser has numerous features that are not available in Firefox private mode:
  
  • security slider;
  • display of packet routing (circuit display);
  • HTTPS Everywhere, NoScript;
  • Tor Launcher;
  • connectable transport protocols;
  • various other improvements.
  
  Now Mozilla decides: perhaps after the merger of functions, it makes sense to make two modes of private surfing (one of them with Tor).

Direct integration with the Onion routing network; one of the features of Tor Browser, which is missing in Firefox private mode

While developers do not have a clear plan, what specific features of Tor Browser will be implemented in Firefox. Of course, ideally, I would like to implement everything except the latest versions of protocols (v3 onion services, etc.).

Representatives of the Tor project understand that in case of full integration of onion routing into Firefox, scalability problems will arise. Simply put, the load on the Onion network will increase dramatically. It is not entirely clear how to solve this problem. Perhaps the rich corporation Mozilla Corp. will provide financial assistance and support for Tor Riley. This is potentially about hundreds of millions of new users on the Tor network every day.

One of the consequences of the merger of Tor and Firefox will be the standardization of the Tor client protocol specifications and the release of open documentation. This is useful for everyone: the more people learn the specifications, the more potential vulnerabilities and weaknesses will be fixed. Mozilla is about to prepare tests for protocol compliance with specifications.

So far, the Fusion project has the status of an experiment. Before merging the code, it is extremely important to make sure that everything works well and does not harm usability - and also to convince everyone of the security of sending Tor code to Firefox. Project Manager "Merge" Ethan Tseng (Ethan Tseng) assures that now the project Fusion is supported at the level of director and technical director of Mozilla Corporation. They believe that in this way they can get functionality in the browser that competitors do not have.

The ultimate goal of this project is to make the Tor Browser obsolete, and then the community can focus on research, rather than on supporting Firefox fork.



The merger of Tor and Mozilla is quite logical, because the projects have the same key values. The fourth principle of the Mozilla Manifesto :

"The security and privacy of Internet users is fundamental and cannot be considered optional."

The main mission of the Tor project:

“Promoting human rights and freedoms by creating and deploying free and open technologies of anonymity and privacy.”

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