Content-Type: text/plain;
	charset=gb2312
Mime-Version: 1.0 (1.0)
From: Mark Friedenbach <mark@friedenbach.org>
In-Reply-To: <20170929020227.GA12192@savin.petertodd.org>
Date: Thu, 28 Sep 2017 19:45:02 -0700
Content-Transfer-Encoding: quoted-printable
Message-Id: <FAD5BE01-52B5-49C6-B018-47BF234A5EF2@friedenbach.org>
References: <359FFE85-86AF-4FBD-9491-3528382E5002@friedenbach.org>
	<20170929020227.GA12192@savin.petertodd.org>
To: Peter Todd <pete@petertodd.org>
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Rebatable fees & incentive-safe fee markets
Precedence: list


> On Sep 28, 2017, at 7:02 PM, Peter Todd <pete@petertodd.org> wrote:
>=20
>> On Thu, Sep 28, 2017 at 06:06:29PM -0700, Mark Friedenbach via bitcoin-de=
v wrote:
>> Unlike other proposed fixes to the fee model, this is not trivially
>> broken by paying the miner out of band.  If you pay out of band fee
>> instead of regular fee, then your transaction cannot be included with
>> other regular fee paying transactions without the miner giving up all
>> regular fee income.  Any transaction paying less fee in-band than the
>> otherwise minimum fee rate needs to also provide ~1Mvbyte * fee rate
>> difference fee to make up for that lost income.  So out of band fee is
>> only realistically considered when it pays on top of a regular feerate
>> paying transaction that would have been included in the block anyway.
>> And what would be the point of that?
>=20
> This proposed fix is itself broken, because the miner can easily include *=
only*
> transactions paying out-of-band, at which point the fee can be anything.

And in doing so either reduce the claimable income from other transactions (=
miner won=A1=AFt do that), or require paying more non-rebateable fee than is=
 needed to get in the block (why would the user do that?)

This is specifically addressed in the text you quoted.=20

> Equally, miners can provide fee *rebates*, forcing up prices for everyone e=
lse
> while still allowing them to make deals.

Discounted by the fact rebates would not be honored by other miners. The reb=
ate would have to be higher than what they could get from straight fee colle=
ction, making it less profitable than doing nothing.=20

> Also, remember that you can pay fees via anyone-can-spend outputs, as mine=
rs
> have full ability to control what transactions end up spending those outpu=
ts.

You=A1=AFd still have to pay the minimum fee rate of the other transactions o=
r you=A1=AFd bring down the miners income. Otherwise this is nearly the same=
 cost as the rebate fee, since they both involve explicit outputs claimed by=
 the miner, but the rebate goes back to you. So why would you not want to do=
 that instead?

A different way of looking at this proposal is that it creates a penalty for=
 out of band payments.=20=