Subject: Re: [bitcoin-dev] Updating the Scaling Roadmap

From: Pieter Wuille <[email-masked]>
Date: Tue, 11 Jul 2017 14:40:36 -0700

On Tue, Jul 11, 2017 at 1:36 PM, Paul Sztorc <[email-masked]> wrote:
> Pieter,
>
> I think that you have misrepresented Chris' view by taking it out of
> context. His complete quote reads "If drivechains are successful they should
> be viewed as the way we scale -- not hard forking the protocol." Chris is
> comparing Drivechains/sidechains to a hard fork.

I apologize here; I didn't mean to misrepresent his viewpoint.

> You went on to "disagree", but every point of contention you introduced was
> something that would apply to both drivechain-sourced capacity and
> hardfork-sourced capacity. Neither improves scalability, and both allow
> users only the opportunity to select a different security model. If I
> understand you, the point at which a security model does not become
> "interesting" to you, would be the exact same point in the drivechain and
> hardfork worlds. Both, at any rate, have the same effect on "validation cost
> to auditors".

If you're talking about the extreme case where every full node in the
increased capacity single chain model corresponds to a node that
validates both chains and all transfers between them in the
drivechains, I agree. At that point they become nearly equivalent in
terms of ease of adoption, resource costs, and capacity.

However, I don't think that is a realistic expectation. When
considering drivechains as a capacity increase, I believe most people
think about a situation where there are many chains that give an
increased capacity combined, but not everyone verifies all of them.
This is what I meant with uninteresting security model, as it requires
increased miner trust for preventing the other chains' coins from
being illegally transferred to the chain you're operating on.

Regardless, people are free experiment and adopt such an approach. The
nice thing about it not being a hardfork is that it does not require
network-wide consensus to deploy. However, I don't think they offer a
security model that should be encouraged, and thus doesn't have a
place on a roadmap.

> Since their sidechain coins cannot appreciate in value relative
> to the mainchain coins, users would only opt-in if they felt that they were
> sufficiently compensated for any and all risks. Hence, it is difficult to
> list this item as a drawback when, to the user, it is a strict improvement
> (at least, by any epistemological standard that I can think of). If you have
> new objections to these claims, I'm sure we would all benefit from hearing
> them, myself most of all.

Am I right in summarizing your point here as "This approach cannot
hurt, because if it were insecure, people can choose to not use it."?
I'm not sure I agree with that, as network effects or misinformation
may push users beyond what is reasonable.

Cheers,

-- 
Pieter