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
|
Return-Path: <luke@dashjr.org>
Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org
[172.17.192.35])
by mail.linuxfoundation.org (Postfix) with ESMTPS id 1C71CB8A
for <bitcoin-dev@lists.linuxfoundation.org>;
Thu, 21 Sep 2017 16:33:34 +0000 (UTC)
X-Greylist: from auto-whitelisted by SQLgrey-1.7.6
Received: from zinan.dashjr.org (zinan.dashjr.org [192.3.11.21])
by smtp1.linuxfoundation.org (Postfix) with ESMTP id B0297421
for <bitcoin-dev@lists.linuxfoundation.org>;
Thu, 21 Sep 2017 16:33:33 +0000 (UTC)
Received: from ishibashi.localnet (unknown
[IPv6:2001:470:5:265:a45d:823b:2d27:961c])
(Authenticated sender: luke-jr)
by zinan.dashjr.org (Postfix) with ESMTPSA id ADE2238A0075;
Thu, 21 Sep 2017 16:33:18 +0000 (UTC)
X-Hashcash: 1:25:170921:jl2012@xbt.hk::uU=N7iBu/q20nafX:F+QN
X-Hashcash: 1:25:170921:bitcoin-dev@lists.linuxfoundation.org::55m/AB/w/p9Zc/aH:+aJA
X-Hashcash: 1:25:170921:mark@friedenbach.org::Zqeo1WaoFVV5hn/U:Tay7
From: Luke Dashjr <luke@dashjr.org>
To: Johnson Lau <jl2012@xbt.hk>
Date: Thu, 21 Sep 2017 16:33:16 +0000
User-Agent: KMail/1.13.7 (Linux/4.12.5-gentoo; KDE/4.14.34; x86_64; ; )
References: <5B6756D0-6BEF-4A01-BDB8-52C646916E29@friedenbach.org>
<201709210411.50642.luke@dashjr.org>
<21D6060D-97F0-439A-86D3-065C21BACC3F@xbt.hk>
In-Reply-To: <21D6060D-97F0-439A-86D3-065C21BACC3F@xbt.hk>
X-PGP-Key-Fingerprint: E463 A93F 5F31 17EE DE6C 7316 BD02 9424 21F4 889F
X-PGP-Key-ID: BD02942421F4889F
X-PGP-Keyserver: hkp://pgp.mit.edu
MIME-Version: 1.0
Content-Type: Text/Plain;
charset="utf-8"
Content-Transfer-Encoding: quoted-printable
Message-Id: <201709211633.17714.luke@dashjr.org>
X-Spam-Status: No, score=1.3 required=5.0 tests=RCVD_IN_DNSWL_MED,
RCVD_IN_SBL_CSS,RP_MATCHES_RCVD autolearn=disabled version=3.3.1
X-Spam-Level: *
X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on
smtp1.linux-foundation.org
Cc: bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] cleanstack alt stack & softfork improvements
(Was: Merkle branch verification & tail-call semantics for
generalized MAST)
X-BeenThere: bitcoin-dev@lists.linuxfoundation.org
X-Mailman-Version: 2.1.12
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: Thu, 21 Sep 2017 16:33:34 -0000
On Thursday 21 September 2017 8:02:42 AM Johnson Lau wrote:
> I think it=E2=80=99s possible only if you spend more witness space to sto=
re the
> (pubkey, message) pairs, so that old clients could understand the
> aggregation produced by new clients. But this completely defeats the
> purpose of doing aggregation.
SigAgg is a softfork, so old clients *won't* understand it... am I missing=
=20
something?
=46or example, perhaps the lookup opcode could have a data payload itself (=
eg,=20
like pushdata opcodes do), and the script can be parsed independently from=
=20
execution to collect the applicable ones.
> > This is another approach, and one that seems like a good idea in genera=
l.
> > I'm not sure it actually needs to take more witness space - in theory,
> > such stack items could be implied if the Script engine is designed for
> > it upfront. Then it would behave as if it were non-verify, while
> > retaining backward compatibility.
>=20
> Sounds interesting but I don=E2=80=99t get it. For example, how could you=
make a
> OP_MUL out of OP_NOP?
The same as your OP_MULVERIFY at the consensus level, except new clients wo=
uld=20
execute it as an OP_MUL, and inject pops/pushes when sending such a=20
transaction to older clients. The hash committed to for the script would=20
include the inferred values, but not the actual on-chain data. This would=20
probably need to be part of some kind of MAST-like softfork to be viable, a=
nd=20
maybe not even then.
Luke
|
