path: root/1a/0e08fe069c1d4931760ed5819a8074d0608f43

Return-Path: <mike@powx.org>
Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137])
 by lists.linuxfoundation.org (Postfix) with ESMTP id 762AAC0001
 for <bitcoin-dev@lists.linuxfoundation.org>;
 Tue, 18 May 2021 12:17:51 +0000 (UTC)
Received: from localhost (localhost [127.0.0.1])
 by smtp4.osuosl.org (Postfix) with ESMTP id 627D4405FA
 for <bitcoin-dev@lists.linuxfoundation.org>;
 Tue, 18 May 2021 12:17:51 +0000 (UTC)
X-Virus-Scanned: amavisd-new at osuosl.org
X-Spam-Flag: NO
X-Spam-Score: -1.898
X-Spam-Level: 
X-Spam-Status: No, score=-1.898 tagged_above=-999 required=5
 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1,
 HTML_MESSAGE=0.001, MIME_QP_LONG_LINE=0.001,
 RCVD_IN_DNSWL_NONE=-0.0001] autolearn=ham autolearn_force=no
Authentication-Results: smtp4.osuosl.org (amavisd-new);
 dkim=pass (2048-bit key) header.d=powx-org.20150623.gappssmtp.com
Received: from smtp4.osuosl.org ([127.0.0.1])
 by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024)
 with ESMTP id ThzyAwk_yf6G
 for <bitcoin-dev@lists.linuxfoundation.org>;
 Tue, 18 May 2021 12:17:48 +0000 (UTC)
X-Greylist: whitelisted by SQLgrey-1.8.0
Received: from mail-qt1-x834.google.com (mail-qt1-x834.google.com
 [IPv6:2607:f8b0:4864:20::834])
 by smtp4.osuosl.org (Postfix) with ESMTPS id 3FB7F40509
 for <bitcoin-dev@lists.linuxfoundation.org>;
 Tue, 18 May 2021 12:17:48 +0000 (UTC)
Received: by mail-qt1-x834.google.com with SMTP id t20so7207557qtx.8
 for <bitcoin-dev@lists.linuxfoundation.org>;
 Tue, 18 May 2021 05:17:48 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
 d=powx-org.20150623.gappssmtp.com; s=20150623;
 h=content-transfer-encoding:from:mime-version:subject:date:message-id
 :references:cc:in-reply-to:to;
 bh=Vr7hrV0SZsnUwlSoTy5jZXZBIycmVog5OfFEOraTLZs=;
 b=E0s97VdInt2rFQ1qGgXIaq+8qEVYiuIO7BqNEo9AA6eVtqxbh8SjPAog2Dhd/f8Yv7
 zDcWo5gLAqqEoRQMiwCFgu6ttv/88NhuA4w3PP4lV1S4R7CEX130Tkb24uaPKAT4hnGC
 /w5FlTnsfAv1jxS5NDdBFTaxUaUQGqsUd9NjH5gWe/fhZ96oYMGELZPcrz3sQsOQ0+06
 +BmkFoJk3nrIHkXNbv27Mt1ZPn+E8iIxPABVrpZtW0UNhfWI7HNjgIJbHUcqGkBCjO2r
 p9AFJy6VZHLzMn/W5TF5p3jRA0nv46G7h8+sfeRjduEwzmCdQtYwTKunwZCSYJ5fFXB8
 TvrA==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
 d=1e100.net; s=20161025;
 h=x-gm-message-state:content-transfer-encoding:from:mime-version
 :subject:date:message-id:references:cc:in-reply-to:to;
 bh=Vr7hrV0SZsnUwlSoTy5jZXZBIycmVog5OfFEOraTLZs=;
 b=TlY/qWQb0mw4tf1daXwlPbAznjiRu1kqqA/bKbmcFd2jGH8V58PRjqt+QJoUDs9hQI
 SWElFM+eK3shs3V4+PTEYHybGS4e1MMpm/rZ+9QskS1W8lU4zIJAdoRaSCwH+HROILAs
 wrvvHibpKKbup267VhJwq1C6iGBQwZZAaEO+bTQNjVuIUiJcDpKu1llAgMyWzVzN1pVA
 4PCCURG0Y1F2MBhxc+jvLZMgwaTACXpNJn2cMvoJyFCMtj2sc8QZKzWKVzJbLmgfcPdU
 i5tABX7Pv6HM7LJzfMJGgyEkCH5ftFUnBsSnlpORsu6k4M22ki18+J4mVP3CEBLZBNuP
 V8RA==
X-Gm-Message-State: AOAM531BouPMOzG58hMlmt+5CkSC58XwsvekGNnFhI3xuWo/w5/CO5ZM
 PAjHQ2X0d27PmVBWGHBUwz6lR519ludOEwju
X-Google-Smtp-Source: ABdhPJyLmHy7NOiWfh9bzk7SOrpFLe2kzP4KM2L6VE3F9LuyHAX4ZS0j1uoin+ViMj/WIUy3YQdowQ==
X-Received: by 2002:ac8:6b0a:: with SMTP id w10mr4365538qts.60.1621340267008; 
 Tue, 18 May 2021 05:17:47 -0700 (PDT)
Received: from [192.168.4.35] ([73.143.249.71])
 by smtp.gmail.com with ESMTPSA id z187sm12652153qkb.129.2021.05.18.05.17.46
 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128);
 Tue, 18 May 2021 05:17:46 -0700 (PDT)
Content-Type: multipart/alternative;
 boundary=Apple-Mail-1E226B23-1DD8-4164-843B-0B81FBF43D4B
Content-Transfer-Encoding: 7bit
From: mike@powx.org
Mime-Version: 1.0 (1.0)
Date: Tue, 18 May 2021 08:17:46 -0400
Message-Id: <864F983C-841D-4334-94F4-5A9F7D617B70@powx.org>
References: <vTGmO3qpvd7XawxARg2vvWmeP2LOCLAIBgMRWmNNmf7mok0DRhIes5JsBnooflSNk4DX2vQCuOB7hBmSjcUT_RvtF6l8gJ9Tt69TWEeowmg=@protonmail.com>
In-Reply-To: <vTGmO3qpvd7XawxARg2vvWmeP2LOCLAIBgMRWmNNmf7mok0DRhIes5JsBnooflSNk4DX2vQCuOB7hBmSjcUT_RvtF6l8gJ9Tt69TWEeowmg=@protonmail.com>
To: ZmnSCPxj <ZmnSCPxj@protonmail.com>
X-Mailer: iPhone Mail (18D70)
X-Mailman-Approved-At: Tue, 18 May 2021 14:24:16 +0000
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>,
 marshall ball <marshallball@gmail.com>
Subject: Re: [bitcoin-dev] Proposal: Low Energy Bitcoin PoW
X-BeenThere: bitcoin-dev@lists.linuxfoundation.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Bitcoin Protocol Discussion <bitcoin-dev.lists.linuxfoundation.org>
List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/bitcoin-dev>, 
 <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=unsubscribe>
List-Archive: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/>
List-Post: <mailto:bitcoin-dev@lists.linuxfoundation.org>
List-Help: <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=help>
List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev>, 
 <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=subscribe>
X-List-Received-Date: Tue, 18 May 2021 12:17:51 -0000


--Apple-Mail-1E226B23-1DD8-4164-843B-0B81FBF43D4B
Content-Type: text/plain;
	charset=utf-8
Content-Transfer-Encoding: quoted-printable

Nothing in a dynamic system like PoW mining can be 100% anticipated, for exa=
mple there might be advanced in manufacturing of chips which are patented an=
d so on.=20

It sounds like your take is that this means no improvements can ever be made=
 by any mechanism, however conservative.

We do go into a fair amount of detail about Minimum Effective Hardness in ou=
r paper https://assets.pubpub.org/xi9h9rps/01581688887859.pdf , which is act=
ually a special case of hardness that we invented for the context of adding a=
n operation to a PoW, and how it applies to random matrix mults.  =20

Sent from my iPhone

> On May 18, 2021, at 7:58 AM, ZmnSCPxj <ZmnSCPxj@protonmail.com> wrote:
>=20
> =EF=BB=BFGood morning Michael,
>=20
>> That=E2=80=99s interesting. I didn=E2=80=99t know the history of ASICBOOS=
T.
>=20
> History is immaterial, what is important is the technical description of A=
SICBOOST.
> Basically, by fixing the partial computation of the second block of SHA256=
, we could selectively vary bits in the first block of SHA256, while reusing=
 the computation of the second block.
> This allows a grinder to grind more candidate blocks without recomputing t=
he second block output, reducing the needed power consumption for the same n=
umber of hashes attempted.
>=20
> Here is an important writeup: https://www.mit.edu/~jlrubin/public/pdfs/Asi=
cboost.pdf
> It should really be required reading for anyone who dreams of changing PoW=
 algorithms to read and understand this document.
>=20
> There may be similar layer-crossings in any combined construction --- or e=
ven just a simple hash function --- when it is applied to a specific Bitcoin=
 block format.
>=20
>>=20
>> Our proposal (see Implementation) is to phase in oPoW slowly starting at a=
 very low % of the rewards (say 1%). That should give a long testing period w=
here there is real financial incentive for things like ASICBOOST
>>=20
>> Does that resolve or partially resolve the issue in your eyes?
>=20
> It does mitigate this somewhat.
>=20
> However, such a mechanism is an additional complication and there may be f=
urther layer-crossing violations possible --- there may be an optimization t=
o have a circuit that occasionally uses SHA256d and occasionally uses oPoW, t=
hat is not possible with a pure SHA256d or pure oPoW circuit.
> So this mitigation is not as strong as it might appear at first glance; ad=
ditional layers means additional possibility of layer-crossing violations li=
ke ASICBOOST.
>=20
>=20
>=20
>=20
> Regards,
> ZmnSCPxj
>=20

--Apple-Mail-1E226B23-1DD8-4164-843B-0B81FBF43D4B
Content-Type: text/html;
	charset=utf-8
Content-Transfer-Encoding: quoted-printable

<html><head><meta http-equiv=3D"content-type" content=3D"text/html; charset=3D=
utf-8"></head><body dir=3D"auto">Nothing in a dynamic system like PoW mining=
 can be 100% anticipated, for example there might be advanced in manufacturi=
ng of chips which are patented and so on.&nbsp;<div><br></div><div>It sounds=
 like your take is that this means no improvements can ever be made by any m=
echanism, however conservative.<div><br></div><div>We do go into a fair amou=
nt of detail about Minimum Effective Hardness in our paper&nbsp;<a href=3D"h=
ttps://assets.pubpub.org/xi9h9rps/01581688887859.pdf">https://assets.pubpub.=
org/xi9h9rps/01581688887859.pdf</a>&nbsp;, which is actually a special case o=
f hardness that we invented for the context of adding an operation to a PoW,=
 and how it applies to random matrix mults. &nbsp;&nbsp;</div><div><br><div d=
ir=3D"ltr">Sent from my iPhone</div><div dir=3D"ltr"><br><blockquote type=3D=
"cite">On May 18, 2021, at 7:58 AM, ZmnSCPxj &lt;ZmnSCPxj@protonmail.com&gt;=
 wrote:<br><br></blockquote></div><blockquote type=3D"cite"><div dir=3D"ltr"=
>=EF=BB=BF<span>Good morning Michael,</span><br><span></span><br><blockquote=
 type=3D"cite"><span>That=E2=80=99s interesting. I didn=E2=80=99t know the h=
istory of ASICBOOST.</span><br></blockquote><span></span><br><span>History i=
s immaterial, what is important is the technical description of ASICBOOST.</=
span><br><span>Basically, by fixing the partial computation of the second bl=
ock of SHA256, we could selectively vary bits in the first block of SHA256, w=
hile reusing the computation of the second block.</span><br><span>This allow=
s a grinder to grind more candidate blocks without recomputing the second bl=
ock output, reducing the needed power consumption for the same number of has=
hes attempted.</span><br><span></span><br><span>Here is an important writeup=
: https://www.mit.edu/~jlrubin/public/pdfs/Asicboost.pdf</span><br><span>It s=
hould really be required reading for anyone who dreams of changing PoW algor=
ithms to read and understand this document.</span><br><span></span><br><span=
>There may be similar layer-crossings in any combined construction --- or ev=
en just a simple hash function --- when it is applied to a specific Bitcoin b=
lock format.</span><br><span></span><br><blockquote type=3D"cite"><span></sp=
an><br></blockquote><blockquote type=3D"cite"><span>Our proposal (see Implem=
entation) is to phase in oPoW slowly starting at a very low % of the rewards=
 (say 1%). That should give a long testing period where there is real financ=
ial incentive for things like ASICBOOST</span><br></blockquote><blockquote t=
ype=3D"cite"><span></span><br></blockquote><blockquote type=3D"cite"><span>D=
oes that resolve or partially resolve the issue in your eyes?</span><br></bl=
ockquote><span></span><br><span>It does mitigate this somewhat.</span><br><s=
pan></span><br><span>However, such a mechanism is an additional complication=
 and there may be further layer-crossing violations possible --- there may b=
e an optimization to have a circuit that occasionally uses SHA256d and occas=
ionally uses oPoW, that is not possible with a pure SHA256d or pure oPoW cir=
cuit.</span><br><span>So this mitigation is not as strong as it might appear=
 at first glance; additional layers means additional possibility of layer-cr=
ossing violations like ASICBOOST.</span><br><span></span><br><span></span><b=
r><span></span><br><span></span><br><span>Regards,</span><br><span>ZmnSCPxj<=
/span><br><span></span><br></div></blockquote></div></div></body></html>=

--Apple-Mail-1E226B23-1DD8-4164-843B-0B81FBF43D4B--