1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
|
Return-Path: <ZmnSCPxj@protonmail.com>
Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137])
by lists.linuxfoundation.org (Postfix) with ESMTP id 38CAFC0001
for <bitcoin-dev@lists.linuxfoundation.org>;
Tue, 18 May 2021 11:36:57 +0000 (UTC)
Received: from localhost (localhost [127.0.0.1])
by smtp4.osuosl.org (Postfix) with ESMTP id 0E78C40616
for <bitcoin-dev@lists.linuxfoundation.org>;
Tue, 18 May 2021 11:36:57 +0000 (UTC)
X-Virus-Scanned: amavisd-new at osuosl.org
X-Spam-Flag: NO
X-Spam-Score: -2.302
X-Spam-Level:
X-Spam-Status: No, score=-2.302 tagged_above=-999 required=5
tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1,
DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001,
FROM_LOCAL_NOVOWEL=0.5, RCVD_IN_DNSWL_LOW=-0.7,
RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001]
autolearn=ham autolearn_force=no
Authentication-Results: smtp4.osuosl.org (amavisd-new);
dkim=pass (1024-bit key) header.d=protonmail.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 o8j6Uj9hK1JC
for <bitcoin-dev@lists.linuxfoundation.org>;
Tue, 18 May 2021 11:36:55 +0000 (UTC)
X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0
Received: from mail-40135.protonmail.ch (mail-40135.protonmail.ch
[185.70.40.135])
by smtp4.osuosl.org (Postfix) with ESMTPS id 83B6440610
for <bitcoin-dev@lists.linuxfoundation.org>;
Tue, 18 May 2021 11:36:55 +0000 (UTC)
Date: Tue, 18 May 2021 11:36:49 +0000
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com;
s=protonmail; t=1621337812;
bh=xMEjY+f8ljezjZxzT4/HLAyB1dlGez1r0MWO+c3/LPE=;
h=Date:To:From:Cc:Reply-To:Subject:In-Reply-To:References:From;
b=IYh78Ld16fvJao+vA+J7yjAFX08UdYP8aEwHt4Akl5wSuuxMWPzAYP0D5MZ/QkqWI
pvVPwqIHVoW/pbjyjkhW8GqmIWZI7f0hFMKCqwzA1K2JgDQNr+alwyQyAj7Iubkn2h
SBe7d5kSA4c9oFo59UNvbbgCDu4qW+LzV8xpDKeM=
To: "mike@powx.org" <mike@powx.org>
From: ZmnSCPxj <ZmnSCPxj@protonmail.com>
Reply-To: ZmnSCPxj <ZmnSCPxj@protonmail.com>
Message-ID: <U-U9RmD3wRndUuQkzjsqm5X8BNnGKcxiIJs-fWbPMiGNaiSlENL4Yn4Ui8vUseIMse_rzgzBmV6EfkdROHEuPbA9vgf7Fkq39Hr9cs-zZbs=@protonmail.com>
In-Reply-To: <CA4E1F20-B266-4E77-96FF-39329C4D825D@powx.org>
References: <WVZvU2OA12RoqS180g1B2ULVCACwaKtdF-75OWKcydI9NUxbaGefYjKAwUklzEef1bIWHghZIotDhCQuxIG5KBX14BmDCEz0wKbNJAkG-ak=@protonmail.com>
<CA4E1F20-B266-4E77-96FF-39329C4D825D@powx.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
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 11:36:57 -0000
Good morning Michael,
> That=E2=80=99s a fair point about patents. However, note that we were car=
eful about this. oPoW only uses SHA3 (can be replaced with SHA256 in princi=
ple as well) and low precision linear matrix multiplication. A whole indust=
ry is trying to accelerate 8-bit linear matrix mults for AI so there is alr=
eady a massive incentive (and has been for decades).
>
> See companies like Mythic, Groq, Tesla (FSD computer), google TPU and so =
on for electronic versions of this. Several of the optical ones are mention=
ed in the BIP (e.g. Lightmatter)
Please note that ASICBOOST for SHA256d is based on a layer-crossing violati=
on: SHA256 processes in blocks, and the Bitcoin block header is slightly la=
rger than one SHA256 block.
Adding more to a direct SHA3 (which, as a "sponge" construction, avoids blo=
cks, but other layer-crossing violations may still exist) still risks layer=
violations that might introduce hidden optimizations.
Or more succinctly;
* Just because the components have (with high probability) no more possible=
optimizations, does not mean that the construction *as a whole* has no hid=
den optimizations.
Thus, even if linear matrix multiplication and SHA3 have no hidden optimiza=
tions, their combination, together with the Bitcoin block header format, *m=
ay* have hidden optimizations.
And there are no *current* incentives to find such optimizations until Bitc=
oin moves to this, at which point we are already committed and it would be =
highly infeasible to revert to SHA256d --- i.e. too late.
This is why changes to PoW are highly discouraged.
Remember, ASICBOOST was *not* an optimization of SHA256 *or* SHA256d, it wa=
s an optimizations of SHA256d-on-a-Bitcoin-block-header.
ASICBOOST cannot speed up general SHA256 or even general SHA256d, it only a=
pplies specifically to SHA256d-on-a-Bitcoin-block-header.
Regards,
ZmnSCPxj
|
