[anti-censorship-team] Identify from which continent people connect from

[mxz+tor-anti-censorship-team at mxzero.de]

Hi,

a while ago (10.02.2023) I tried to send an email on the tor-talk 
mailing list but apparently it never got through as it's still awaiting 
approval. (it wasn't denied either, afaik)

So, I'll try my luck here as this is sort of censorship related, too.

Copy and paste of the email:

---

Hi,

recently, there was an interesting side note on the cryptography mailing 
list [1].
Quote:

> (People have written code to predict what continent an anonymous person using Tor is on, based on noticing over a period of time when 
their remote system clocks ran faster or slower, assuming that was 
caused by nighttime versus daytime temperatures.)

I was wondering if any of you know about this and where I could find 
code that does this? Any links to research and papers would be highly 
appreciated, too.

Especially, I'm wondering how they do this:

- via differences in the above mentioned system clock (impressive?!)
- timing analysis with latency? things like lower latency in Europe as 
there are more tor relays around compared to Argentina.
- do you need to have any prerequisites? e.g. controlling at least one 
node, or the exit node, or a "clear text" server/hidden service that 
someone connects to?


Finally, if that's the wrong list, please refer me to the right one.
Thanks!


[1]: 
https://www.metzdowd.com/pipermail/cryptography/2023-February/038109.html