[tor-bugs] #20348 [Metrics/Censorship analysis]: Kazakhstan blocking of vanilla Tor, 2016-06

Fri Oct 28 20:04:22 UTC 2016

#20348: Kazakhstan blocking of vanilla Tor, 2016-06
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 Reporter:  dcf                          |          Owner:
     Type:  project                      |         Status:  new
 Priority:  Medium                       |      Milestone:
Component:  Metrics/Censorship analysis  |        Version:
 Severity:  Normal                       |     Resolution:
 Keywords:  censorship block kz          |  Actual Points:
Parent ID:                               |         Points:
 Reviewer:                               |        Sponsor:
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Comment (by cypherpunks):

 First segment used as source for entropy test to decide if stat analysis
 for stream need. But it's somehow too complex.
 Tested with a first segment of 256 bytes. For non modified obfs4 it
 triggers detection reliably. If to replace random padding with zeroes
 (segment contains elligator-2 and zeroes then) then no detection happens.
 But if to keep size of segment (still with elligator-2 as non zero bytes
 only) to mss then detection happens (thought not so reliably).

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Ticket URL: <https://troodi.torproject.org/projects/tor/ticket/20348#comment:13>
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