Hey everyone! Here are our meeting logs: http://meetbot.debian.net/tor-meeting/2025/tor-meeting.2025-07-24-16.00.html And our meeting pad: Anti-censorship work meeting pad -------------------------------- Anti-censorship -------------------------------- Next meeting: Thursday, July 31 16:00 UTC Facilitator: shelikhoo ^^^(See Facilitator Queue at tail) Weekly meetings, every Thursday at 16:00 UTC, in #tor-meeting at OFTC (channel is logged while meetings are in progress) This week's Facilitator: onyinyang == Goal of this meeting == Weekly check-in about the status of anti-censorship work at Tor. Coordinate collaboration between people/teams on anti-censorship at the Tor Project and Tor community. == Links to Useful documents ==     * Our anti-censorship roadmap:         * Roadmap:https://gitlab.torproject.org/groups/tpo/anti-censorship/-/boards     * The anti-censorship team's wiki page:         * https://gitlab.torproject.org/tpo/anti-censorship/team/-/wikis/home     * Past meeting notes can be found at:         * https://lists.torproject.org/pipermail/tor-project/     * Tickets that need reviews: from projects, we are working on:         * All needs review tickets:             * https://gitlab.torproject.org/groups/tpo/anti-censorship/-/merge_requests?sc...         * Project 158 <-- meskio working on it             * https://gitlab.torproject.org/groups/tpo/anti-censorship/-/issues/?label_nam... == Announcements ==     * == Discussion ==     * dan crashing to talk about Tor VPN app signing strategy and consequences         * will be distributed over 3 mediums (tpo website, google play and fdroid)         * sharing the key over the 3 mediums will make possible for users to switch upgrade channels if one gets blocked         * google wants access to the private key         * the plan is to share the key between fdroid and tpo, but have a different key for google         * TorBrowser Android doesn't have that problem because is an old app and google don't require keys for old apps         * meskio will coordinate with applications team to see how to integrate TorVPN in gettor == Actions == == Interesting links ==     * FOCI 2025.2 proceedings https://foci.community/foci25.html         * "Fingerprint-resistant DTLS for usage in Snowflake" by theodorsm https://www.petsymposium.org/foci/2025/foci-2025-0006.pdf         * "Encrypted Client Hello (ECH) in Censorship Circumvention"         https://www.petsymposium.org/foci/2025/foci-2025-0016.pdf     * PETS 2025         * "CenPush: Blocking-Resistant Control Channel Using Push Notifications" by cohosh et al. https://petsymposium.org/popets/2025/popets-2025-0153.pdf == Reading group ==     * We will discuss "Encrypted Client Hello (ECH) in Censorship Circumvention" on August 14         * https://www.petsymposium.org/foci/2025/foci-2025-0016.pdf         * Questions to ask and goals to have:             * What aspects of the paper are questionable?             * Are there immediate actions we can take based on this work?             * Are there long-term actions we can take based on this work?             * Is there future work that we want to call out in hopes that others will pick it up? == Updates == Name:         This week:             - What you worked on this week.         Next week:             - What you are planning to work on next week.         Help with:             - Something you need help with. cecylia (cohosh): 2025-07-24     Last week:         - dependency upgrades         - release snowflake-webext 0.9.4         - opened issue for weird proxy count graphs (snowflake#40472)         - finished adapting client poll metrics scripts for rendezvous method counts (snowflake#40464)         - wrote a fix to get country metrics for ampcache polls (snowflake!591)         - opened an issue about FIFO vs LIFO (snowflake#40473)         - worked on investigating snowflake rendezvous errors (snowflake#40447)     This week:         - follow-up on new conjure bridge set up(conjure#46)         - start work around snowflake enumeration attacks             - https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowf...         - follow up on snowflake rendezvous failures         - take a look at potential snowflake orbot bug             - https://github.com/guardianproject/orbot-android/issues/1183 dcf: 2025-07-24     Last week:     Next week:         - open issue to have snowflake-client log whenever KCPInErrors is nonzero https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowf...             - parent: https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowf... Help with: meskio: 2024-07-24     Last week:         - recommend snowflake in russia over circumventions settings (rdsys-admin!42)         - add a prometheus alerts on a drop of snowflake client polls (team#161)         - fix the rdsys staging test-authority deploy (tpa/team#41769)         - reassign moat bridges (rdsys#233)         - review the situation of Tor in Togo (censorship-analysis#40066)         - some more report reviews     Next week:         - wrap up P158 (rdsys staging) Shelikhoo: 2024-07-24     Last Week:          - [Testing] Unreliable+unordered WebRTC data channel transport for Snowflake rev2 (cont.)( https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowf... ) testing environment setup/research          - Create new webtunnel release(STALLED BY ISSUE BELOW)          - Unexpected Gitlab Runner Failure from Rate Limiting (https://gitlab.torproject.org/tpo/tpa/team/-/issues/42245)          - Add Domain Fronting Test Support to probeobserver ( https://gitlab.torproject.org/tpo/anti-censorship/connectivity-measurement/p... )         - Vantge point maintaince         - Merge request reviews     Next (working) Week/TODO:         - Merge request reviews         - Support the Testing of domain fronting sites ( https://gitlab.torproject.org/tpo/anti-censorship/connectivity-measurement/l... ) (cont.)         - Create webtunnel release v0.0.3         - invesgate webtunnel domain fronting support and dynamic bridge support onyinyang: 2025-07-24     Last week(s):         - Finished up work on  webtunnel button         - Added some logs to help debug https://gitlab.torproject.org/tpo/anti-censorship/rdsys/-/issues/249 Next week:         - Next is looking into this mystery: https://gitlab.torproject.org/tpo/anti-censorship/rdsys/-/issues/262#note_32...         - Vacation next 2 weeks       Switch back to some of these:           As time allows:                Blog post for conjure: https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/conju...               - review Tor browser Lox integration https://gitlab.torproject.org/tpo/applications/tor-browser/-/merge_requests/...               - add TTL cache to lox MR for duplicate responses: https://gitlab.torproject.org/tpo/anti-censorship/lox/-/merge_requests/305         - Work on outstanding milestone issues:             - key rotation automation         Later:         pending decision on abandoning lox wasm in favour of some kind of FFI? https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/43096):             - add pref to handle timing for pubkey checks in Tor browser             - add trusted invitation logic to tor browser integration: https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/42974         - improve metrics collection/think about how to show Lox is working/valuable         - sketch out Lox blog post/usage notes for forum     (long term things were discussed at the meeting!):         - brainstorming grouping strategies for Lox buckets (of bridges) and gathering context on how types of bridges are distributed/use in practice             Question: What makes a bridge usable for a given user, and how can we encode that to best ensure we're getting the most appropriate resources to people?                 1. Are there some obvious grouping strategies that we can already consider?                     e.g., by PT, by bandwidth (lower bandwidth bridges sacrificed to open-invitation buckets?), by locale (to be matched with a requesting user's geoip or something?)                 2. Does it make sense to group 3 bridges/bucket, so trusted users have access to 3 bridges (and untrusted users have access to 1)? More? Less? theodorsm: 2025-06-12         Last weeks:             - Applying for funding from NLnet to implement DTLS 1.3 in Pion. Got through the first round.             - Writing paper for FOCI: continuation of master thesis about reducing distinguishability of DTLS in Snowflake by implementing covert-dtls, further analysis of collected browser fingerprint and stability test of covert-dtls in snowflake proxies. Draft: https://theodorsm.net/FOCI25             - Key takeaways:                 * covert-dtls is stable when mimicking DTLS 1.2 handshakes, while the randomization approach— though more resistant to fingerprinting — tends to be less stable.                 * Chrome webextensions are more unstable than standalone proxies                 * covert-dtls should be integrated in Snowflake proxies as they produce the ClientHello messages during the DTLS handshake.                 * Chrome randomizes the order of extension list.                 * Firefox uses DTLS 1.3 by default in WebRTC.                 * A prompt adoption of DTLS 1.3 in both Snowflake and our fingerprint-resistant library is needed to keep up with browsers                 * The evolution of browsers’ fingerprints had no noticeable effect on Snowflake’s number of daily users over the last year.                 * Even with a sharp drop in the amount of proxies, it does not seem to affect the number of Snowflake users.                 * Browser extensions make Snowflake resistant to ClientHello fingerprinting.                 * Standalone proxies can serve more Snowflake clients per volunteer than webextensions.                 * We need metrics on which types of proxies are actually being matched and successfully used by clients.         Next weeks:             - Getting paper camera ready.             - Fix merge conflicts in MR (https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowf...).         Help with:             - Should we do user testing of covert-dtls? Facilitator Queue:         onyinyang shelikhoo meskio 1. First available staff in the Facilitator Queue will be the facilitator for the meeting 2. After facilitating the meeting, the facilitator will be moved to the tail of the queue -- --- onyinyang GPG Fingerprint 3CC3 F8CC E9D0 A92F A108 38EF 156A 6435 430C 2036