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Re: [tor-talk] How to find trust nodes?

On Thu, Sep 28, 2017 at 07:31:56AM +0000, Jason Long wrote:
:Excuse me if I say it, but your answers make me confuse more!!! I guess there is no guarantee about Tor nodes. Governments and bad people can launch a Tor node and sniff Tor users traffic and... 

The design of Tor is that you don't need to trust all the nodes. You
just need to be sure the first one and the last in any connection
chain aren't run by the *same* malicious actor.

:On Thu, 9/28/17, Seth David Schoen <schoen@xxxxxxx> wrote:
: Subject: Re: [tor-talk] How to find trust nodes?
: To: tor-talk@xxxxxxxxxxxxxxxxxxxx
: Date: Thursday, September 28, 2017, 1:41 AM
: George writes:
: > But ultimately, Tor's topography
: mitigates against one of the three
: >
: nodes in your circuit being compromised. If the first hop
: is
: > compromised, then they only know who
: you are, but not where your
: > destination
: is. If the last hop is compromised, they only know where
: > you're going, but not who you are
: (unless your providing clear text of
: >
: personally identifying information).
: A challenge is that there are threat models in
: which a considerable number
: of Tor users may
: be exposed, at least for some of their circuits.
: * If a single adversary runs
: several fast nodes that are popular and whose
:   relationship to each other is undisclosed, a
: pretty high amount of traffic
:   may select
: that adversary's nodes as entry and exit nodes for the
: same
:   circuit.  The guard node design
: gives a relatively low probability of this
:   happening to any individual user with
: respect to any individual
:   adversary in
: any specific time period, but doesn't guarantee that
: it
:   would be a particularly rare event for
: Tor users as a whole.
: * If
: adversaries cooperate, they can get benefits equivalent to
: running many
:   nodes even though each one
: only runs a few.
: * If an
: adversary can monitor network activity and see both entry
: and exit
:   points, for a given circuit, it
: can perform correlations even though
:   it
: doesn't operate any nodes.  Or, an adversary that can
: monitor some
:   networks can increase its
: chance of getting visibility of both ends of
:   a connection by also operating some nodes,
: since some users whose entry
:   or exit
: activity the adversary otherwise wouldn't have been able
: to
:   monitor from network surveillance
: alone may sometimes randomly choose to
: use that adversary's nodes in one of these positions.
: * An adversary that can
: monitor some kind of public or private online
:   activity can perform coarse-grained timing
: correlation attacks between
:   its own entry
: nodes (or parts of the Internet where it can see Tor
:   node entry) and the online activity that it
: can see.  For example, if a
:   user
: regularly uses Tor to participate in some kind of public
: forum,
:   public chat, etc., the adversary
: could gather data about how entry
:   traffic
: that it can see does or doesn't correlate with that
: participation.
:   Or if an adversary can
: obtain logs about the use of a particular online
:   service, even though those logs aren't
: available to the general public,
:   it can
: also correlate that statistically with entry data that it
: has
:   available for some other reason.
: The "good news" is
: that a given Tor user is probably not very likely to
: be vulnerable to many of these attacks from
: many adversaries when using
: Tor infrequently
: or for brief periods.  Yet many of these attacks would
: work at least some of the time against a pretty
: considerable amount of
: Tor traffic.
: I agree with your point that
: just having more random people run nodes
: helps decrease the probability of success of
: several of these attacks.
: -- 
: Seth Schoen  <schoen@xxxxxxx>
: Senior Staff Technologist             
:          https://www.eff.org/
: Electronic Frontier Foundation           
:       https://www.eff.org/join
: 815 Eddy Street, San Francisco, CA  94109   
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