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	<20170406023123.GA1071@savin.petertodd.org>
From: Bram Cohen <bram@bittorrent.com>
Date: Wed, 5 Apr 2017 19:39:08 -0700
Message-ID: <CA+KqGkqSxeAUZFVFqM_QkEWcGFHgZXwGuOE==7HpXp1+D_Tj3Q@mail.gmail.com>
To: Peter Todd <pete@petertodd.org>, 
	Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Content-Type: multipart/alternative; boundary=001a114ac8f6d03947054c7669bc
Subject: Re: [bitcoin-dev] BIP proposal: Inhibiting a covert attack on the
 Bitcoin POW function
Precedence: list

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On Wed, Apr 5, 2017 at 7:31 PM, Peter Todd via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

>
> While I'm in favour of blocking covert usage of ASICBOOST, there's every
> reason
> to block non-covert usage of it as well. In a low margin business like
> mining,
> the advatange it gives is enormous - quite possibly 10x your profit margin
> -
> and given that barrier free access to being able to purchase ASICs is
> already
> an archilles heal for Bitcoin there is every reason to eliminate this legal
> vulnerability. Additionally, it's a technical vulnerability as well: we
> want
> getting into the ASIC manufacturing and design business to have as low
> barriers
> to entry as is feasible, and the ASICBOOST exploit significantly increases
> the
> minimum capital requirements to do so.
>

Asicboost also has the problem that it isn't treating the hashing as a
black box, and thus has impacts on what gets mined. In particular it
creates an incentive to make blocks smaller. That's a very unwanted effect,
and anything like it should be engineered out on principle.

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<div dir=3D"ltr"><div class=3D"gmail_extra"><div class=3D"gmail_quote">On W=
ed, Apr 5, 2017 at 7:31 PM, Peter Todd via bitcoin-dev <span dir=3D"ltr">&l=
t;<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" target=3D"_blank=
">bitcoin-dev@lists.linuxfoundation.org</a>&gt;</span> wrote:<br><blockquot=
e class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc sol=
id;padding-left:1ex"><span class=3D""><br>
</span>While I&#39;m in favour of blocking covert usage of ASICBOOST, there=
&#39;s every reason<br>
to block non-covert usage of it as well. In a low margin business like mini=
ng,<br>
the advatange it gives is enormous - quite possibly 10x your profit margin =
-<br>
and given that barrier free access to being able to purchase ASICs is alrea=
dy<br>
an archilles heal for Bitcoin there is every reason to eliminate this legal=
<br>
vulnerability. Additionally, it&#39;s a technical vulnerability as well: we=
 want<br>
getting into the ASIC manufacturing and design business to have as low barr=
iers<br>
to entry as is feasible, and the ASICBOOST exploit significantly increases =
the<br>
minimum capital requirements to do so.<br></blockquote><div><br></div><div>=
Asicboost also has the problem that it isn&#39;t treating the hashing as a =
black box, and thus has impacts on what gets mined. In particular it create=
s an incentive to make blocks smaller. That&#39;s a very unwanted effect, a=
nd anything like it should be engineered out on principle.</div></div></div=
></div>

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