Anti-censorship team report: August 2020
September 04, 2020
Tor’s anti-censorship team writes monthly reports to keep the world updated on its progress. This blog post summarizes the anti-censorship work we got done in August 2020. Let us know if you have any questions or feedback!
We set up an anonymous bug-reporting pad for the team. Take a look at our reporting instructions:
NAT type matching in Snowflake browser proxies. Released version 0.4.1 of the browser extension.
Perform a test for symmetric NATs on startup.
Implemented a fix so Snowflake stops using the client’s network when Tor isn’t making reqests.
Hashik Donthineni, our GSoC 2020 student, successfully finished his Android proxy app project! It needs more UI improvements and testing before being ready for use.
Made progress on allowing clients to split traffic across multiple proxies.
Updated Snowflake stats to include counts of restricted, unrestricted, and unknown proxies.
Inspected several months worth of BridgeDB’s HTTPS distributor logs and distilled a few insights.
Took a closer look at bot scraping attempts.
Decided to call our BridgeDB redesign rdsys, which is short for “resource distribution system.” Do you have a better name? If so, let us know!
Created a GitLab repository for rdsys. The code is a messy construction site and will continue to be in the foreseeable future.
Improved the way rdsys talks to bridgestrap to verify that bridges are working.
Built an HTTP streaming interface between rdsys’s backend and its distributors. This interface allows the backend to stream resource updates to the distributors without delay. The goal is that resources (i.e. bridges) are distributed to users immediately after they are added to the system.
- Implemented a crude prototype of the Salmon bridge distribution mechanism. Brainstormed a handful of privacy-preserving features that would improve the original design.
Improved the service’s shutdown procedure, caching mechanism, its documentation, and its HTTP API. Added a command line flag to print bridgestrap’s cache.
Added a token bucket mechanism to limit the number of requests that the service accepts.
- Updated the resources that emma tries to connect to (replaced a guard relay and removed the default bridge “frosty”). Changed trac links to GitLab links.
- Retired the default bridge “frosty” because the colocation site where the bridge was running will be shut down.
Published a blog post on our challenges, priorities, and progress.
Published our July 2020 report as blog post.
David presented his Turbo Tunnel paper at FOCI’2020. His talk is available online:
Roger participated in a FOCI’2020 panel on “Internet Freedom in the Domestic Arena.”
Cecylia was a panelist at Tor’s latest PrivChat iteration, called “the Good, the Bad, and the Ugly of Censorship Circumvention.” The recording is available online: