[tor-talk] Tor and P2P

[Seth David Schoen]

meh. writes:

> After implementing the torchat protocol and seeing how bad it is, but
> how nice the idea is, I started thinking it would be cool to have a
> more general protocol for P2P use through hidden services.
> 
> My question is, how would it scale and what would be the implications
> of such a system (every user would be a hidden service and would be
> constantly connected to other hidden services it wants to interact
> with)?

I wonder if there's a way to extend the protocol to do ephemeral
hidden services (that are only meant to be used once for a single
inbound connection, perhaps, and that can be set up very quickly
with low overhead).  This might be something like the "reply onion"
concept in the original onion routing, where you can create an
object that represents an explicit route to reach a particular Tor
end user (but where the route is opaque to its users, so they don't
know where the connection they establish with it will go).

My limited understanding of onion routing history is that reply
onions were replaced by hidden services, which are meant to be
long-lived and usable by many clients.  I don't know whether reply
onions disappeared solely on efficiency grounds or whether there
are also bad security consequences.

In existing hidden services both sides are building a path through
the Tor network to the rendezvous, so you don't just have one side
choosing the complete path.  I have a vague recollection that there
are bad consequences if you allow one party to choose another party's
complete path through the network -- presumably based on the idea of
making the other party use an entry node secretly controlled by the
hidden service operator (!!!) in order to identify them.

-- 
Seth Schoen  <schoen at eff.org>
Senior Staff Technologist                       https://www.eff.org/
Electronic Frontier Foundation                  https://www.eff.org/join
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