[tor-dev] Proposal: Merging Hidden Service Directories and Introduction Points

[Tom van der Woerdt]

Op 12/07/15 om 23:48 schreef John Brooks:
> Hello!
>
> George and I, along with the other participants of this hidden services
> meeting, have written a proposal for the idea to merge hidden service
> directories and introduction points into the same entity along with proposal
> 224.
>
> Comments are encouraged, especially if there are downsides or side effects
> that we haven’t written about yet, or that you have a different opinion on.
> The intent is that we can decide to do this before implementing proposal
> 224, so they can be implemented together.
>
> The proposal is attached, and also available from:
>
> https://raw.githubusercontent.com/special/torspec/224-no-hsdir/proposals/ideas/xxx-merge-hsdir-and-intro.txt
>
> Thanks!
>
> - John


Earlier today in Berlin we discussed this proposal a bit and we noticed 
a small hack we could do here to make #246 backwards compatible: instead 
of changing the descriptor format, we could choose to publish an only 
slightly different descriptor to the nodes in the hsdir ring, including 
only the introduction point that is the node in the hsdir which the 
descriptor gets published to. That way, the client will already have the 
circuit to the right node, and could just re-use it.

Example: imagine 2 HSdirs, one at 1.2.3.4, and one at 5.6.7.8. The 
client will talk to one of these HSdirs to fetch the descriptor, and it 
will find that if it connects to 5.6.7.8 it gets only a single 
introduction point (that being 5.6.7.8), and if it had asked the 
directory on 1.2.3.4 it would have been told to introduce itself at 
1.2.3.4. The client can then re-use the circuit to do the introduction.

The speedup may only be noticeable to nodes that actually re-use the 
circuit, but all clients will at least keep working.

Tom