[tor-talk] Please Remove Tor bridge and... from Censorship countries.

Seth David Schoen schoen at eff.org
Mon Nov 7 17:56:01 UTC 2016


Jason Long writes:

> To be honest, I guess that I must stop using Tor!!!! It is not secure.I can remember that in torproject.org the Tor speaking about some peole that use Tor. For example, reporters, Military soldiers and...But I guess all of them are ads. Consider a soldier in a country that want send a secret letter to his government and he want to use Tor but the country that he is in there can sniff his traffic :( 

That soldier has a potential problem if the government is aggressively
monitoring Internet traffic, because they can look at the time that the
message was received and ask "who was using Tor in our country at that
time?".  This happened in 2013 when someone sent a bomb threat using
Tor on his university campus.  Apparently he was the only person using
Tor on campus at the time the threat was sent.

http://www.dailydot.com/crime/tor-harvard-bomb-suspect/

The ability to do this doesn't require the government to operate any of
the nodes and doesn't require them to be operated in the same country.
For instance, Harvard University was able to identify this person even
though he was using only Tor nodes that were outside of the university's
network.  (It might have been much harder if he had been using a bridge
that the university didn't know about, or if he had sent the threat
from somewhere outside of the campus network.)

If there are ways of sending the letter that introduce a delay, then it
might be harder for the government to identify the soldier because then
there is some amount of Tor use at a time that's not obviously related
to the sending of the letter.  There might still be a concern that the
amount of data that the soldier transmitted over the Tor network is
very similar to the size of the letter, which may be a unique profile.
(That's a concern for systems like SecureDrop because people upload
large documents with a unique size; the number of people who transmitted
that exact amount of information on a Tor connection in a particular
time frame will be very small.)

There's lots to think about and a good reminder that the Tor technology
isn't perfect.  But I wouldn't agree with the idea that there's no point
in using Tor.  Lots of people are getting an anonymity benefit from
using it all of the time.

-- 
Seth Schoen  <schoen at eff.org>
Senior Staff Technologist                       https://www.eff.org/
Electronic Frontier Foundation                  https://www.eff.org/join
815 Eddy Street, San Francisco, CA  94109       +1 415 436 9333 x107


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