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From: mike@powx.org
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Date: Tue, 18 May 2021 07:05:44 -0400
Message-Id: <CA4E1F20-B266-4E77-96FF-39329C4D825D@powx.org>
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To: ZmnSCPxj <ZmnSCPxj@protonmail.com>
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Proposal: Low Energy Bitcoin PoW
Precedence: list

That=E2=80=99s a fair point about patents. However, note that we were carefu=
l about this. oPoW only uses SHA3 (can be replaced with SHA256 in principle a=
s well) and low precision linear matrix multiplication.  A whole industry is=
 trying to accelerate 8-bit linear matrix mults for AI so there is already a=
 massive incentive (and has been for decades).=20

See companies like Mythic, Groq, Tesla (FSD computer), google TPU and so on f=
or electronic versions of this. Several of the optical ones are mentioned in=
 the BIP (e.g. Lightmatter)

Sent from my iPhone

> On May 18, 2021, at 6:59 AM, ZmnSCPxj <ZmnSCPxj@protonmail.com> wrote:
>=20
> =EF=BB=BFGood morning devrandom,
>=20
>> On Mon, May 17, 2021 at 11:47 PM ZmnSCPxj:
>>=20
>>> When considering any new proof-of-foo, it is best to consider all effect=
s until you reach the base physics of the arrow of time, at which point you w=
ill realize it is ultimately just another proof-of-work anyway.
>>=20
>> Let's not simplify away economic considerations, such as externalities.  T=
he whole debate about the current PoW is about negative externalities relate=
d to energy production.
>>=20
>> Depending on the details, CAPEX (R&D, real-estate, construction, producti=
on) may have less externalities, and if that's the case, we should be intere=
sted in adopting a PoW that is intensive in these types of CAPEX.
>=20
> Then let us also not forget another important externality: possible optimi=
zations of a new PoW algorithm that risk being put into some kind of exclusi=
ve patent.
>=20
> I think with high probability that SHA256d as used by Bitcoin will no long=
er have an optimization as large in effect as ASICBOOST in the future, simpl=
y because there is a huge incentive to find such optimizations and Bitcoin h=
as been using SHA256d for 12 years already, and we have already found ASICBO=
OST (and while patented, as I understand it the patent owner has promised no=
t to enforce the patent --- my understanding may be wrong).
>=20
> Any alternative PoW algorithm risks an ASICBOOST-like optimization that is=
 currently unknown, but which will be discovered (and possibly patented by a=
n owner that *will* enforce the patent, thus putting the entire ecosystem at=
 direct conflict with legacy government structures) once there is a good inc=
entive (i.e. use in Bitcoin) for it.
>=20
> Regards,
> ZmnSCPxj