On 3 Oct 2017, at 10:57, Roman Mamedov rm@romanrm.net wrote:
On Tue, 3 Oct 2017 09:53:46 -0400 teor teor2345@gmail.com wrote:
For interposing dual-protocoled nodes along the way, how many do there have to be for it to become "not too limiting"?
This is one of the questions we need researchers to answer.
I can't help but feel you are overcomplicating this.
Clients create a circuit by randomly picking 3 nodes out of the all-nodes pile, right? If all 3 happen to be IPv6-capable, then the circuit can go over IPv6 and all is fine. If some of the 3 happen to be IPv6-only while others are IPv4-only, the whole selection can be thrown away and repeated.
That way IPv6-only relays could get some usage on a totally random basis, with no compromises and no restraining "of the next hop based on the previous one", not hurting anonymity. Clients just need to know which nodes are IPv4-only, IPv6-only or dual-stack, to not attempt unworkable combinations, discarding them instead.
Discarding unworkable combinations and restraining node choices seem equivalent to me, although the relay weights may be different.
And as there are more and more dual-stack or IPv6-only relays, the "throw away" step will be needed less and less often.
If you think this will work and is safe for client anonymity, then the next step is to write a tor proposal. Having a concrete design could help with analysing the anonymity implications as well.
I think IPv6-only relays are a lower priority than better IPv6 and dual-stack client support, and IPv6-only bridge support But we could do both in the same release.
Tim