Re: Block directory authorities, is it possible?

[Roger Dingledine <arma@xxxxxxx>]

On Sat, Jan 13, 2007 at 07:41:57PM +0800, Kevin Smith wrote:
> Why hasn't Tor been blocked in China already? Torpark is redirecting
> to the Google homepage (1). The psiphon homepage has been blocked. The
> Freegate homepage is blocked. Why not Tor?

My guesses, in order of ease-of-explanation:

A) There are perhaps 30000 people in China running Tor clients right now,
according to my rough estimates. That's roughly zero people, in China.

B) The general perception of Tor is that it's a tool for experts. So
they don't think they need to block it (yet).

C) We haven't publically threatened their control. By emphasizing
government/military/law enforcement use, and individuals in free countries
who need their civil liberties, we don't force them to take action.

D) Other?

> Could it be that Tor is being used to help identify suspected
> dissidents? Consider the following:
> 
> I'm sitting at my home in Beijing using Tor. The Chinese internet
> police see my computer periodically connecting to a Tor directory
[snip]
> national elections. Not too likely that he is a dissident.
> 
> Wang Guolu is sitting at home using Tor. The Chinese internet police
[snip]
> of being a member of the FLG. A relatively low paid factory worker
> using advanced internet anonymizing software? That just screams
> dissident.

As I understand it, social networking attacks are much simpler
and more successful. Having an informer at the factory is much more
straightforward, and just the *possibility* of it is usually enough to
make a lot of people self-censor.

In fact, as countries restrict more information at their national
firewall, they end up with *more* Tor users -- not because they're all
dissidents, but because they want to read the web comics or stock market
sites they were able to read last week. The mere fact that you use Tor
in these cases is not "much" evidence on you, as long as there's a
sufficient population around you using Tor.

So yes, they could do what you describe, but there are many things they
*could* do, and from talking to people in China, this probably isn't
first in line in terms of worries. But let me know if you disagree. :)

--Roger