[tor-bugs] #9001 [Tor]: Slow Guard Discovery of Hidden Services and Clients

Mon Jun 17 00:28:00 UTC 2013

#9001: Slow Guard Discovery of Hidden Services and Clients
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 Reporter:  mikeperry                        |          Owner:                    
     Type:  defect                           |         Status:  new               
 Priority:  major                            |      Milestone:  Tor: 0.2.5.x-final
Component:  Tor                              |        Version:                    
 Keywords:  tor-hs path-bias needs-proposal  |         Parent:                    
   Points:                                   |   Actualpoints:                    
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Comment(by rransom):

 The only solution is to add a second layer of guards (‘identity guards’?),
 dependent on the client's ‘identity’ (as determined by the same things
 that control stream isolation).

 This fix has some prerequisites:
  * Tor relays must use a UDP-based link protocol exclusively, for multiple
 security reasons.  (Some entry nodes might allow their clients to connect
 using other link protocols.)
  * Clients must be able to choose a set of identity guards
 deterministically from a ''non-uniform'' (e.g. load-balanced) distribution
 according to a seed (#2653 gives one approach).
  * Each client application must be associated with one or more persistent
 identities.  Otherwise, using identity guards only adds a moderate delay
 in finding a client's entry guards.
  * In order to avoid linking a client's identities, Tor clients must not
 allow any information about the Tor network or destination servers
 obtained through one identity to affect any behaviour of its other
 identities.  (This requires that adaptive CBT and the path-bias detector
 be removed, and that many client-side caches be isolated to a single
 identity.)

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/9001#comment:6>
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