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refraction-networking
utls
Go2021–2024
refraction-networking / utls

utls

Fork of the Go standard TLS library, providing low-level access to the ClientHello for mimicry purposes.

7Distinct people
7Mentions
0Explicit recommenders
2.6KGitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

Fork of the Go standard TLS library, providing low-level access to the ClientHello for mimicry purposes.

GitHub

Where it is used

No documented product use has been verified yet.

What people are saying

No recommendation phrase was found in the indexed comments.

No classified warning is attached to this page. Read the discussions before treating silence as approval.

Also in these discussions

No other repository is repeatedly linked in the same discussions.

This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 1:49:46 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year7 dated mentions

Observed mentions: 2021-10-11 18:09:06 UTC to 2024-12-30 13:07:21 UTC.

01232021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments20212022-01-01 00:00:00 UTC to 2023-01-01 00:00:00 UTC (exclusive): 3 mentions; 0 submissions, 3 comments20222023-01-01 00:00:00 UTC to 2024-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2024-01-01 00:00:00 UTC to 2025-01-01 00:00:00 UTC (exclusive): 3 mentions; 1 submissions, 2 comments2024

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC101
20222022-01-01 00:00:00 UTC2023-01-01 00:00:00 UTC303
20232023-01-01 00:00:00 UTC2024-01-01 00:00:00 UTC000
20242024-01-01 00:00:00 UTC2025-01-01 00:00:00 UTC312

What Hacker News says

7 sources
Fascinating, Filippo. We stayed silent on it at the time primarily because we were keeping a low profile particularly as more and more Chinese were using Lantern, but there was also back channel pressure through various contacts, to be honest related to the pending Cloudflare expansion in China. There was also a prelude to all of this that I think made things stickier and bizarrely personal. Prince and I share a mutual friend who introduced us just a few weeks prior. Prince said he supported what we were doing, but asked that I not talk about it publicly, presumably because of the pending China deal. The problem was that literally moments after our friend had introduced us via email, and before he made that request, I had a call with the WSJ where I talked about precisely this. I did everything I could to walk back the article, but Prince
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didn't buy it and seemed to go ballistic over it. After the WSJ piece, we pulled back from talking more publicly in general. Oh, I forgot! We also partly stayed silent because they didn't actually shut down what we were doing at all =). They matched the SNI to the Host header, sure, but they missed a little detail: we weren't using SNI. Hehe. Lantern worked for another six months or so, and then, through a similarly bizarre sequence of events, we essentially tipped them/you off to what was happening. We remained a customer throughout, and we're a customer to this day. Either way, though, Cloudflare does great work, and everyone has their faults, so I'm generally sympathetic over the whole thing with the one caveat that I am truly unclear how much ultimately did relate to China, most clearly in terms of any public support for these internet freedom techniques. Oh, and I've wanted you to work on Lantern forever btw. Oooh actually if you're not aware of it, the uTLS Go TLS fork is a hugely impactful project that's in widespread use (I would guess maybe 50 million monthly active users rely on it in censored regions via various projects) but needs updating - https://github.com/refraction-networking/utls Oh, and if you think we were effective in China then, you should see what we're doing in Russia and especially Iran now!
In Tell HN: Domain fronting to be blocked on Azure
"The answer is sort of yes - browsers aren't magic! All the information browsers send to your backend is just HTTP requests. So if I copy all of the HTTP headers that my browser is sending, I think there's literally no way for the backend to tell that the request isn't sent by my browser and is actually being sent by a random Python program." There is a way.^1 One might need to copy the static elements of the TLS Client Hello in addition to certain HTTP headers. 1. https://blog.squarelemon.com/tls-fingerprinting/ See, e.g., https://github.com/refraction-networking/utls "problem 1: expiring session cookies One big problem here is that I'm using my Google session cookie for authentication, so this script will stop working whenever my browser session expires. That means that this approach wouldn't work for a long running program (I'd want t
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o use a real API), but if I just need to quickly grab a little bit of data as a 1-time thing, it can work great!" Sometimes Google keeps users logged in. For example, session cookies in Gmail will last for months or more. This makes it easy to check Gmail from the command line without a browser. It also means if someone steals a session cookie and the user never logs out, e.g., she closes the browser without logging out first,^2 then the thief can access the account for months, or longer. 2. Of course, it is also possible to logout and disable specific session cookies from the command line, without a browser.
In How to use undocumented web APIs

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