On https://2019.www.torproject.org/docs/onion-services it says that whenever the client or server contacts the rendezvous point or one introduction point, it always builds a full tor circuit.

So, why does it say (near the ending) that

In general, the complete connection between client and onion service consists of 6 relays: 3 of them were picked by the client with the third being the rendezvous point and the other 3 were picked by the onion service.

It implies a circuit of 2 relays from the client to the RP. Maybe the client builds a full circuit to the RP only at the beginning (to share the one-time-secret) and then later uses it as third node?

  • I don't understand the question here. The RP is chosen by the client and is part of the client's circuit (it's the third hop). Why does this imply a circuit of 2 relays? A "full tor circuit" in this case is a circuit with three hops, where each hop was chosen by the party building the circuit.
    – Steve
    Nov 21, 2020 at 18:54
  • @Steve If RP is the third hop, then there aren't 3 nodes between the client and the RP. It would be (client)--> (1st relay) --> (2nd relay) --> (RP). That's not a full circuit. Nov 21, 2020 at 18:57
  • There aren't supposed to be 3 nodes between the client and the RP. The RP is part of the circuit. So the client builds a 3 hop circuit (1st relay) -> (2nd relay) -> (RP), and the onion service builds a 4 hop circuit (1st relay) -> (2nd relay) -> (3rd relay) -> (RP). Note that the page you linked to is old and no longer maintained.
    – Steve
    Nov 21, 2020 at 19:00
  • Mmh... but on that site it says: "Around this time, the client also creates a circuit to another randomly picked relay and asks it to act as rendezvous point by telling it a one-time secret." All the green arrows in the pictures are supposed to be circuits, full circuits. I thought it was updated to 2019. Nov 21, 2020 at 19:06
  • It's probably just the original author trying to simplify things. Tor doesn't really have a concept of "full circuits". A circuit is considered anonymous if it has three relays chosen independently by the client (or whoever is building the circuit).
    – Steve
    Nov 21, 2020 at 19:13


You must log in to answer this question.

Browse other questions tagged .