Re: [Bitcoin-development] Proposal: SPV Fee Discovery mechanism

[Nathan Wilcox <nathan@leastauthority.com>]

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On Wed, Jun 10, 2015 at 2:03 PM, Peter Todd <pete@petertodd.org> wrote:

> On Wed, Jun 10, 2015 at 02:00:27PM -0600, Nathan Wilcox wrote:
> > On Wed, Jun 10, 2015 at 1:19 PM, Aaron Voisine <voisine@gmail.com>
> wrote:
> >
> > > It could be done by agreeing on a data format and encoding it in an
> > > op_return output in the coinbase transaction. If it catches on it could
> > > later be enforced with a soft fork.
> > >
> > >
> > Sounds plausible, except SPV protocols would need to include this
> coinbase
> > txn if it's going to help SPV clients. (Until a softfork is activated,
> SPV
> > clients should not rely on this encoding, since until that time the
> results
> > can be fabricated by individual miners.)
>
> Fee stats can always be fabricated by individual miners because fees can
> be paid out-of-band.
>
>
This is a point I hadn't considered carefully before. I don't understand
the marketplace here or why miners would want to move fees outside of
explicit inband fees. Implicit in this proposal is that the statistics only
cover in-band data, because that's the scope of consensus rules, and thus
the proposal is only as useful as the information of in-band fees is useful.

I've also noticed a detracting technical argument given a particular
tradeoff:

A Header-PoW-verifying client could still be given all transactions in a
recent block, from which it can see the in-band fees directly.  The
trade-off is the size of those transactions versus the need to alter any
consensus rules or do soft forks.

Notice how this trade-off's costs change with maximum block size.




> --
> 'peter'[:-1]@petertodd.org
> 00000000000000001245bd2f5c99379ee76836227ded9c08324894faabc0d27f
>



-- 
Nathan Wilcox
Least Authoritarian

email: nathan@leastauthority.com
twitter: @least_nathan
PGP: 11169993 / AAAC 5675 E3F7 514C 67ED  E9C9 3BFE 5263 1116 9993

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