[tor-bugs] #30716 [Circumvention/Obfs4]: Improve the obfs4 obfuscation protocol

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#30716: Improve the obfs4 obfuscation protocol
-------------------------------------------------+-------------------------
 Reporter:  phw                                  |          Owner:  phw
     Type:  task                                 |         Status:
                                                 |  assigned
 Priority:  High                                 |      Milestone:
Component:  Circumvention/Obfs4                  |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  sponsor28, anti-censorship-roadmap-  |  Actual Points:
  october                                        |
Parent ID:                                       |         Points:  20
 Reviewer:                                       |        Sponsor:
                                                 |  Sponsor28-must
-------------------------------------------------+-------------------------

Comment (by phw):

 I stumbled upon an implementation issue that's also worth fixing:
 obfs4proxy always closes an obfs4 connection after 30 seconds if a client
 was unable to authenticate itself. This facilitates active probing
 attacks. We should instead close connections after a server-specific,
 randomly-determined time interval.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/30716#comment:15>
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