Re: [briar-devel] Gnunet

[Greg T. <gd...@le...>]

Michael Rogers <mi...@br...> writes:

>> How does briar do multicast in a forum?
>
> Each forum starts out with one subscriber, the user who created it. Any
> subscriber can share the forum with chosen contacts, so the forum
> spreads through the social graph and the subscribers form a subgraph of
> the social graph. We say that two users are syncing the forum if there's
> an edge between them in the subgraph. In other words they both
> subscribe, and one of them shared the forum with the other, and the
> other accepted. (It's possible that they both subscribe but they're not
> syncing the forum, ie there's no edge between them in the subgraph.)
>
> Whenever a subscriber receives a new forum post - either one that she
> wrote herself or one that she received from a contact - she offers it to
> any contacts she's syncing the forum with. If they haven't already seen
> it, they request it and she sends it. So the post is flooded through the
> subgraph without sending any redundant copies.
>
> Blogs use the same mechanism, except that posts have to be signed by the
> blog's author, so any subscriber can share the blog, but only the author
> can create posts that the subscribers will accept and propagate.
>
> Private groups are also similar to forums, except the creator is the
> only subscriber who's allowed to share the group. Each subscriber's
> messages must be rooted in a join message co-signed by the creator, so
> nobody else can create messages that the subscribers will accept and
> propagate.

Thanks for the clear explanation.  I had wondered about that, and not
really understood from reading the user manual.  In particular I did not
realize that users other than blog originator should invite to the
blog.  So a blog is really just a 1-author forum, which makes sense for
popular people reaching an audience without noise.

A further point is that the notion that only the originator can control
access to a private group is enforced in software, and there is no way
to prevent bad behvavior by contacts you share with.   Perhaps that's
really obvious, but there's a big difference between
"cryptographically can't" and "briar norms say you can't and the current
software respects those norms".

Presumably all these things have timeouts/lifetimes.  Or perhaps Briar
hasn't been in use long enough for that to be clearly necessary.



Sort of getting off topic, but I wonder about a way to have briar nodes
convey private messages sometimes (in the e2e-encrypted form of course).
I realize you don't want to flood this to all nodes or untrusted nodes,
for scaling and to avoid enabling traffic analysis.  In a region without
Internet, it would be nice to have messages flow via opportunistic
couriers, so that if A has addressed a message to C, meets and syncs
with B, and later B syncs with C, C will get the message. 

I wonder about some sort of private group that either has a "flood
unicast messages among members" option, or is a different flavor of
private group, or something else.