[tor-bugs] #9498 [Tor]: Allow bridge descriptors to contain no address if they are not being published

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#9498: Allow bridge descriptors to contain no address if they are not being
published
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     Reporter:  nwf          |      Owner:
         Type:  enhancement  |     Status:  new
     Priority:  normal       |  Milestone:  Tor: 0.2.5.x-final
    Component:  Tor          |    Version:  Tor: unspecified
   Resolution:               |   Keywords:  tor-bridge,need-spec,bridgedb
Actual Points:               |  Parent ID:
       Points:               |
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Comment (by isis):

 Replying to [comment:4 atagar]:
 > * Arm does not presently use bridge descriptors (it only uses general
 descriptor information available through the controller interface).

 Derp. Misremembered. I think I had a dream once where arm showed me all
 kinds of magical statistics about bridges, perhaps some of that interface
 accidentally melded.

 > * Wiping the address would prevent metrics from producing the sanaitized
 addresses in the [https://metrics.torproject.org/formats.html#bridgedesc
 bridge format it publishes]. I suspect for Karsten's purposes he would
 like the address to be something unique (not blanked to 0.0.0.0), though
 it probably fine for it to be inaccurate. You should double check with
 him.

 Although, keeping them all the same might be neat, because it would allow
 aggregate statistics on private bridge usage. That might be safer, or more
 privacy-preserving, Karsten would probably know.

 The other thing that could be neat is if some range were set aside, like
 using 127.255.0.0/16 (though this might raise other problems), but then we
 run into problems if we ever expect to have more than 2^16^ IPv4 bridges.
 Using entirely random addresses would definitely be a bad idea, because
 BridgeDB would think these were real bridges at these addresses, and start
 handing them out to users, who wouldn't be able to connect to them. Not to
 mention the birthday problem would apply to collisions, but this seems
 negligible because the total ipv4 address space is 2^24^. Still, I'm not
 sure what tor does if two ORs claim to have the same address with
 different keys. Or what the DirAuths do.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/9498#comment:5>
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