[tor-bugs] #9767 [Tor]: Implement proposal 222: Eliminate client timestamps in Tor

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#9767: Implement proposal 222: Eliminate client timestamps in Tor
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     Reporter:  nickm    |      Owner:
         Type:  defect   |     Status:  needs_review
     Priority:  major    |  Milestone:  Tor: 0.2.4.x-final
    Component:  Tor      |    Version:
   Resolution:           |   Keywords:  tor-client fingerprinting time
Actual Points:           |  prop222
       Points:           |  Parent ID:
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Comment (by andrea):

 Replying to [comment:10 nickm]:
 > Replying to [comment:7 andrea]:
 > > Further thought on TLS/SSL timestamps: if NSA can MITM the connection
 and forge a server certificate with an expiration date of their choice,
 and the client strictly tests the expiration date against the local clock,
 then whether the client continues the handshake also leaks information
 about clock skew.  The client is probably fucked regardless in that case,
 but in the NAT/mobile client scenario under discussion it is a capability
 beyond just what the MITM alone would give them.
 >
 > Sure; for this patch, I'm not hypothesizing a fast cheap
 RSA1024-breaker, but a simple time-recorder.  We should defend against the
 former too (see proposal 220), but the latter is easier to exploit, and
 simpler to fix, I think?

 Yeah, I think so too - still need to read proposal 220.  I was just musing
 on whether we really need to actually check the expiration date on the
 relay's server certificate I guess.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/9767#comment:13>
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