[tor-project] Anti-censorship team monthly report: September 2020

[Philipp Winter]

Hi all,

Here's what the anti-censorship team accomplished in September 2020:

Snowflake
---------

* Merged a contribution from Peter Gerber to consider more IP address
  ranges local, for the purpose of stripping from SDP offers sent to the
  broker.

Rdsys
-----

* Built an HTTP streaming API between rdsys's backend and its
  distributors that allows distributors to receive resource updates
  (e.g. a bridge changing its IP address) in real-time.

* Implemented a registration API that allows standalone-proxies (i.e.
  without a corresponding Tor bridge) to register themselves:
  https://gitlab.torproject.org/tpo/anti-censorship/rdsys/-/issues/4

* Added lots of unit tests.  Rdsys's domain logic is 72.1% tested.

* Experimented with reCAPTCHA support in rdsys.  We could port
  BridgeDB's HTTPS distributor to rdsys and replace our Gimp-generated
  CAPTCHAs with Google's reCAPTCHA.  To prevent exposing our users to
  Google, we would have to set up a reverse proxy, so Google only gets
  to see our machine's IP address.  This is possible but messy to build.

* Started brainstorming Salmon's user interface; in particular how we
  can best integrate it in Tor Browser:
  https://gitlab.torproject.org/tpo/anti-censorship/rdsys/-/issues/7

* Started writing up rdsys's design and architecture.  The goal is to
  eventually publish a technical blog post that discusses how we built
  rdsys.

Bridgestrap
-----------

* Wrapped up a "minimum viable product" of bridgestrap:
  https://gitlab.torproject.org/tpo/anti-censorship/trac/-/issues/31874

* Filed issues to improve how bridgestrap spawns a Tor instance to test
  bridges:
  https://gitlab.torproject.org/tpo/anti-censorship/bridgestrap/-/issues/1
  https://gitlab.torproject.org/tpo/anti-censorship/bridgestrap/-/issues/2
  https://gitlab.torproject.org/tpo/anti-censorship/bridgestrap/-/issues/3

Miscellaneous
-------------

* Our infrastructure monitoring daemon's emails started getting rejected
  by Gandi's spam filter.  We reported the issue and Gandi fixed it
  shortly after.

* Read the HTTPT paper as part of our reading group and filed several
  issues that summarise what's necessary to deploy HTTPT as our next
  pluggable transport:
  https://github.com/net4people/bbs/issues/50
  https://censorbib.nymity.ch/#Frolov2020b
  https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/httpt/-/issues

* Filed an issue to improve our terminology around bridges:
  https://gitlab.torproject.org/tpo/anti-censorship/rdsys/-/issues/8

* Brainstormed how Tor Browser could detect censorship:
  https://gitlab.torproject.org/tpo/applications/tor-browser-spec/-/issues/40004

Outreach
--------

* Philipp will present rdsys in a lightning talk at the Pluggable
  Transport Implementer's Meeting on Oct 13:
  https://www.pluggabletransports.info/ptim2020/

* Published a blog post about Hashik's experience as one of Tor's
  GSoC'20 students:
  https://blog.torproject.org/gsoc-2020-snowflake-proxy-mobile

* Recorded a brief video that summarises Tor's anti-censorship work for
  a class at the University of Michigan.