[tor-bugs] #17315 [Pluggable transport]: explain replay prevention in obfs4 spec

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#17315: explain replay prevention in obfs4 spec
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 Reporter:  arma                 |          Owner:  asn
     Type:  defect               |         Status:  new
 Priority:  normal               |      Milestone:
Component:  Pluggable transport  |        Version:
 Keywords:                       |  Actual Points:
Parent ID:                       |         Points:
  Sponsor:                       |
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 phw informs me that obfs4 does indeed have replay prevention (where if you
 record the client traffic and send it again, you don't get to learn if
 it's an obfs4 bridge). But when I look at
 https://gitweb.torproject.org/pluggable-
 transports/obfs4.git/tree/doc/obfs4-spec.txt
 then the word 'replay' doesn't show up.

 How does the protection work? Should it be in the spec?

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/17315>
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