Received-SPF: pass (sog-mx-3.v43.ch3.sourceforge.com: domain of gmail.com
	designates 209.85.192.50 as permitted sender)
	client-ip=209.85.192.50;
	envelope-from=stephencalebmorse@gmail.com;
	helo=mail-qg0-f50.google.com; 
Content-Type: text/plain;
	charset=us-ascii
Mime-Version: 1.0 (1.0)
From: Stephen <stephencalebmorse@gmail.com>
In-Reply-To: <20150509030833.GA28871@savin.petertodd.org>
Date: Sat, 16 May 2015 00:39:53 -0400
Content-Transfer-Encoding: quoted-printable
Message-Id: <9BBD3F51-2FE0-4861-B045-6ACFC48AA21D@gmail.com>
References: <554BE0E1.5030001@bluematt.me>
	<CANEZrP3uKLvzKi-wXBJWL=pwqB+eAe3FbPjyESD52y5TGkg+Rg@mail.gmail.com>
	<20150508163701.GA27417@savin.petertodd.org>
	<CAE-z3OV8zyUyYiGNRZZbTkUZz70KK7P-ENyhsKe+yhZmNnqRuQ@mail.gmail.com>
	<20150509030833.GA28871@savin.petertodd.org>
To: Peter Todd <pete@petertodd.org>
Cc: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] Block Size Increase Requirements
Precedence: list

Comments in line:

> On May 8, 2015, at 11:08 PM, Peter Todd <pete@petertodd.org> wrote:
>=20
> Makes it trivial to find miners and DoS attack them - a huge risk to the
> network as a whole, as well as the miners.
>=20
> Right now pools already get DoSed all the time through their work
> submission systems; getting DoS attacked via their nodes as well would
> be a disaster.

It seems that using a -miner flag to follow rules about smaller blocks would=
 only reveal miner nodes if one sent the node a solved block that that was v=
alid in every way except the block size. While not impossible, I wouldn't ca=
ll this trivial, as it still requires wasting an entire block's worth of ene=
rgy.=20

>> When in "miner mode", the client would reject 4MB blocks and wouldn't bui=
ld
>> on them.  The reference client might even track the miner and the non-min=
er
>> chain tip.
>>=20
>> Miners would refuse to build on 5MB blocks, but merchants and general use=
rs
>> would accept them.
>=20
> That'd be an excellent way to double-spend merchants, significantly
> increasing the chance that the double-spend would succeed as you only
> have to get sufficient hashing power to get the lucky blocks; you don't
> need enough hashing power to *also* ensure those blocks don't become the
> longest chain, removing the need to sybil attack your target.
>=20

I think this could be mitigated by counting confirmations differently. We sh=
ould think of confirmations as only coming from blocks following the miners'=
 more strict rule set. So if a merchant were to see payment for the first ti=
me in a block that met their own size restrictions but not the miners', then=
 they would simply count it as unconfirmed.=20

If they get deep enough in the chain, though, the client should probably cou=
nt them as being confirmed anyway, even if they don't meet the client nodes'=
 expectation of the miners' block size limit. This happening probably just m=
eans that the client has not updated their software (or -minermaxblocksize c=
onfiguration, depending on how it is implemented) in a long time.=20

I actually like Tier's suggestion quite a bit. I think we could have the def=
ault client limit set to some higher number, and have miners agree out of ba=
nd on the latest block size limit. Or maybe even build in a way to vote into=
 the blockchain.=20

Best,=20
Stephen=