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[liberationtech] Images of Blocking in Different Countries?

Jacob Appelbaum jacob at appelbaum.net
Wed Aug 15 14:34:05 PDT 2012


Eric S Johnson:
> Hi Phillipp,
> 
>  
> 
>> Eric, that's interesting, could you elaborate on that?
> 
>> According to my own experience, deep packet inspection in China is still used
> 
>  
> 
> I'm not saying China doesn't do DPI.  I'm just saying that, from my own experience living in China for the past three years, DPI doesn’t appear to be used to inspect the contents of web pages and dynamically block undesirable content.
> 

Hrm. You did actually say:

"Yes-they stopped doin packet inspection in about 2008, near as I can tell."

That's a bit confusing as we've seen direct evidence of DPI that results
in real time *probing* of Tor bridges. We know they do DPI to do this
and we know they trigger specific kinds of censorship depending on protocol.

That you are not seeing content being *blocked* is not the same as the
absence of DPI that is performing surveillance, protocol classification,
logging and eventually, blocking.

>  
> 
> I.e. it's easy to register a new domain (call it TestChinaCyberFiltering.org) and put up onto it a handful of pages which include every possible word and phrase which we know are problematic to the Chinese censors. Start with the list of words which trigger censorship and surveillance in TOM Skype (the wordlist's been repeatedly cracked by researchers at, I think, Arizona). Add all the content which the good folks at UC-Berkeley’s China Digital Times have detected cause immediate censorship on Weibo (China’s Twitter-like service). This should be a total of about 400 words and phrases (almost all only in Chinese).
> 
>                Then access those pages from within China.
> 
>                As far as I can tell, access will be unimpeded.
> 
>                It appears to me such content won't ever get blocked unless/until it's indexed in Google. It appears that the Great Firewall is constantly doing Google searches for undesirable content, then augmenting the blacklist. It seems to me the actual augmentation happens only after the "bad" content's been reviewed by a human. And although most of what we read about involves what's blocked, there do seem to be regular reductions in what's blocked--perhaps about once a quarter.
> 
>                But my own tests have been unscientific, i.e. not conducted over a variety of ISPs, times, and content. It would be interesting (and not difficult) to do this more rigorously.
>


If you put up such a site, I guess a lot of people here would run their
tests and let us all know the results. That seems like a good way to
test your theory and to test their tests.

All the best,
Jake




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