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Date: Mon, 28 Dec 2015 15:26:43 -0500
Message-ID: <CAAre=ySPjm+cyLdBY_CZkLdfXE3OFYgECEUq05AyWfY0q1KuTQ@mail.gmail.com>
From: Ivan Brightly <ibrightly@gmail.com>
To: Peter Todd <pete@petertodd.org>
Content-Type: multipart/alternative; boundary=001a114c78fe9377ed0527fb1f05
Cc: Bitcoin Dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] We need to fix the block withholding attack
Precedence: list

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>
> On Mon, Dec 28, 2015 at 2:12 PM, Peter Todd via bitcoin-dev <
> bitcoin-dev@lists.linuxfoundation.org> wrote:
> Far more concerning is network propagation effects between large and
> small miners. For that class of issues, if you are in an environemnt
> where selfish mining is possible - a fairly flat, easily DoS/sybil
> attacked network topology - the profitability difference between small
> and large miners even *without* attacks going on is a hugely worrying
> problem. OTOH, if you're blocksize is small enough that propagation time
> is negligable to profitability, then selfish mining attacks with <30%
> hashing power aren't much of a concern - they'll be naturally defeated
> by anti-DoS/anti-sybil measures.
>

Let's agree that one factor in mining profitability is bandwidth/network
reliability/stability. Why focus on that vs electricity contracts or
vertically integrated chip manufacturers? Surely, sufficient network
bandwidth is a more broadly available commodity than <$0.02/kwh
electricity, for example. I'm not sure that your stranded hydroelectric
miner is any more desirable than thousands of dorm room miners with access
to 10gbit university connections and free electricity.

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<div dir=3D"ltr"><div class=3D"gmail_extra"><div class=3D"gmail_quote"><blo=
ckquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left=
-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;paddi=
ng-left:1ex">On Mon, Dec 28, 2015 at 2:12 PM, Peter Todd via bitcoin-dev=C2=
=A0<span dir=3D"ltr">&lt;<a href=3D"mailto:bitcoin-dev@lists.linuxfoundatio=
n.org" target=3D"_blank">bitcoin-dev@lists.linuxfoundation.org</a>&gt;</spa=
n>=C2=A0wrote:<br>
Far more concerning is network propagation effects between large and<br>
small miners. For that class of issues, if you are in an environemnt<br>
where selfish mining is possible - a fairly flat, easily DoS/sybil<br>
attacked network topology - the profitability difference between small<br>
and large miners even *without* attacks going on is a hugely worrying<br>
problem. OTOH, if you&#39;re blocksize is small enough that propagation tim=
e<br>
is negligable to profitability, then selfish mining attacks with &lt;30%<br=
>
hashing power aren&#39;t much of a concern - they&#39;ll be naturally defea=
ted<br>
by anti-DoS/anti-sybil measures.<br></blockquote><div><br></div><div>Let=
9;s agree that one factor in mining profitability is bandwidth/network reli=
ability/stability. Why focus on that vs electricity contracts or vertically=
 integrated chip manufacturers? Surely, sufficient network bandwidth is a m=
ore broadly available commodity than &lt;$0.02/kwh electricity, for example=
. I&#39;m not sure that your stranded hydroelectric miner is any more desir=
able than thousands of dorm room miners with access to 10gbit university co=
nnections and free electricity.</div></div></div></div>

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