Hi Loz,
On Wed, Aug 15, 2012 at 11:00:11PM +0800, Lorenz Kirchner wrote:
I guess, that would require a modification of the path selection on the clients side. Usually, Tor clients randomly pick relays weighted by bandwidth. Unless the Chinese relays would provide an enormous amount of bandwidth, they would barely get selected by clients which leads to a poor user experience.
well compared to now the experience would be better, eventually the reachable Chinese relays would connect it just might take a while on first startup
Yes, assuming the users would not give up out of frustration before :-) We can actually do the math: According to [0], at the moment the Tor network has an advertised bandwidth of 3000 MiB/s. Let's assume that all Chinese relays would account for 30 MiB/s. Even then, the probability of a Chinese relay being selected as first hop is only 30/3000 = 0.01 = 1%!
Perhaps it's better to focus on improved bridge distribution strategies [0] and hard-to-block transport protocols [1]. Also, that would be a universal solution which would also help in other countries and not a specific - and probably hard to maintain - Chinese-only solution.
I think the solution is not a Chinese only solution as it would work anywhere where censorship actually exists
Only if you assume that the censor is always having a hard time censoring content within its own borders. That might hold more-or-less true for China but not everywhere else, right? For example, what about the networks of a company or a small organization?
I guess, the firewall operators would notice that quite soon when Chinese relays would start popping up in the consensus or am I missing something here? And as soon as something is in the consensus, it's particularly easy to block.
I am not sure how it works but I have a feeling that the firewall operators have difficulties in blocking hosts inside their networks
That might be due to the fact that a lot of filtering (but not all of it) is going on in border ASes. There even is a research paper about that if you are interested [1].
However, there still remains a legal problem! You will have a hard time hiding the fact that you are operating a relay within China. And if this turns out to be a viable strategy, even more so. I suppose it wouldn't be too hard for the government to simply confiscate or shut down Chinese relays?
After all, I agree with you that it's an interesting strategy which would tackle the problem from a new angle and I would love to learn more about it. I just believe that right now we should spend the limited resources we have on bridge distribution and pluggable transports. It would surely be worth an experiment, though!
Philipp
[0] https://metrics.torproject.org/network.html#bandwidth [1] www.eecs.umich.edu/~zmao/Papers/china-censorship-pam11.pdf