[tor-talk] Finding relay Sybils / Groups [re: relay_early/blackhat]
vitteaymeric at gmail.com
Wed Jul 30 21:27:14 UTC 2014
Le 30/07/2014 20:10, grarpamp a écrit :
> There may be more questionable relays to be found.
We see in the description of this attack some subtle details, along with
a list of papers/studies.
The problem is that the Tor network is really too small in terms of
efficient nodes, so if you add the proper amount of efficient nodes a
correlation attack seems easy without any subtility.
Taking Guards and Exit nodes, asking Onionoo you get something like 1000
for each (version > 2.3.0).
Testing them you were used to get 500 for each (ie really working at
Filtering on bandwitdth > 2 MBps for Guards, you were used to get 250
Among the remaining number of exit nodes it's not rare that some have
some specific exit policies, ie exiting nothing, so a not negligible
number to be banned.
Trying this right now gives (unexpectedly) only 121 Guards (> 2MBps) and
130 Exit nodes, really working.
Behind these numbers, the issue is still how to add efficient nodes not
controlled by the same people, maybe it could be envisioned to evolve to
a more decentralized system where small nodes can be efficient.
Peersm : http://www.peersm.com
node-Tor : https://www.github.com/Ayms/node-Tor
GitHub : https://www.github.com/Ayms
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