[Lightning-dev] Proposal for rendez-vous routing

[CJP]

Rusty,

In your proposal, I guess it is more or less widely known that Bob is
providing this forwarding service. Wouldn't Bob risk being excluded
from the side of the network with the more harsh regulatory conditions,
based on this knowledge? Bob might actually face even worse penalties
for providing such a service.

The nice thing about rendez-vous routing is that *any* forwarding node
can be a rendez-vous point, and even the node itself wouldn't know
about it. The case where a payment is routed from and to the same
channel could be a hint though: normally that makes no sense, but if
payer and payee make their part of the route independently, the
combined route can often end up  like that. TODO: check if forwarding
nodes are currently cool with such weird forwarding requests.

CJP


Rusty Russell schreef op ma 05-11-2018 om 10:56 [+1030]:
> CJP <cjp at ultimatestunts.nl> writes:
> > > Looking through BOLT 4, the text assumes inherently that source
> > > routing is done, and even has a shared secret between hop and
> > > source.  However, it may be possible in rendezvous routing to
> > > simply
> > > provide the blinding key (while hiding everything beyond the
> > > first
> > > hop on the destination half of the route).
> > 
> > Sounds like it makes sense; I need to look into it.
> 
> Here's my attempt to design a "merchant forward" service using stuff
> we
> have today.
> 
> Alice wants to remain anonymous, even from the lightning
> network.  Bob's
> node offers a forwarding service.  Alice pays Bob (base +
> percentage?),
> gives a path Bob->Alice, and Bob gives Alice a short-channel-id
> (BobAliceSCID) and privkey to use (BobAliceSecretKey).  Anything sent
> from Bob to this short channel id and pubkey is in fact forwarded via
> a
> new HTLC to Alice.
> 
> Alice identity BobAliceKey to create an invoice, with a route-hint to
> say pubkey=Bob, short_channel_id=BobAliceSCID.  Alice can sign
> that invoice, and Bob can decode the incoming payment, from which it
> creates a new HTLC to pay Alice.  The payer doesn't even know this
> arrangement exists: it looks exactly like Alice has a private channel
> with Bob.
> 
> The minor downside: because we conflate invoice keys (Alice needs)
> and
> onion keys (Bob needs), Bob can now issue invoices as Alice.  It's
> not
> very useful, since Alice won't honor them, but it is an argument for
> a separate invoice key in future.
> 
> Cheers,
> Rusty.