On Tue, Aug 21, 2012 at 11:25 PM, tagnaq wrote:

I think karsten's graphs from #6443 fit also well to this thread:

Bingo b in the first graph in the ticket [1] you see that the probability gets to ~80% when the number of nodes gets to 40. What this graph doesn't show, however, is that many of these nodes are attached to the same switch, or even run on same machine in different VMs, or on different IPs (some even run on same IP). After accounting for that, the number of tiny networks (at least /28, from going over the list in the original message) and nodes one needs to intercept in order to get the same 80% figure gets down to ~25. And of course, if one is smarter about choosing which nodes to intercept, the probability of seeing both entry and exit traffic is also significant: ~25%. It is also possible to do something in between (choose some Guard-only and Exit-only nodes), but my laziness kicked in at that point of analysis. Here are the network again, in case anyone has the resources and is curious enough about who does what with Tor: DE 31.172.30.[1-4] GB 146.185.23.179 NL 77.247.181.{162,164} RO 109.163.233.{200-201,205} CA 198.96.155.3 US 199.48.147.[35-41] DE 212.84.206.250 FR 178.32.211.{130,140} US 204.8.156.142 US 173.254.216.[66-69] SE 78.108.63.44 US 96.44.189.102 GB 178.33.169.35 CZ 212.79.110.28 US 66.180.193.219 DE 88.198.100.{230,233} LU 212.117.180.65 SE 81.170.186.175 CH 62.220.135.129 SE 84.55.117.251 DE 85.31.187.132 CA 8.18.172.156 FR 213.251.185.74 US 69.42.212.2 FR 37.59.82.50 [1] https://trac.torproject.org/projects/tor/attachment/ticket/6443/exit-probabi... -- Maxim Kammerer LibertC) Linux: http://dee.su/liberte _______________________________________________ tor-talk mailing list tor-talk@lists.torproject.org https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-talk ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE