[tor-bugs] #11743 [Tor]: nodelist_add_microdesc: assign md to all appropriate nodes properly

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#11743: nodelist_add_microdesc: assign md to all appropriate nodes properly
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     Reporter:  cypherpunks  |      Owner:
         Type:  defect       |     Status:  new
     Priority:  major        |  Milestone:  Tor: 0.2.5.x-final
    Component:  Tor          |    Version:
   Resolution:               |   Keywords:  tor-relay needs-proposal
Actual Points:               |  Parent ID:
       Points:               |
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Comment (by nickm):

 Replying to [comment:8 cypherpunks]:
 > > nodes really ''shouldn't'' share microdescriptors.
 >
 > But auths could to generate md with the same hash for two different
 relays from consensus, just because hash collision nature.

 Well, we're never going to see an *accidental* collision in SHA256.
 (That's about a P=2^-128^ event, and those are basically impossible.)

 > And no simple solution to fix that, it's tricky to drop consensus with
 such colliding md.
 > Client shouldn't crash if that happens at least.

 Right.

 For now, what do you think of "bug11743_option_b" to prevent collisions
 from duplicate onion keys? It should make md collisions as hard as SHA256
 collisions, which should be out of reach for a while.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/11743#comment:9>
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