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
|
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 BC618D84
for <bitcoin-dev@lists.linuxfoundation.org>;
Fri, 26 Feb 2016 02:35:36 +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 6F69711F
for <bitcoin-dev@lists.linuxfoundation.org>;
Fri, 26 Feb 2016 02:35:36 +0000 (UTC)
Received: from ishibashi.localnet (unknown
[IPv6:2001:470:5:265:61b6:56a6:b03d:28d6])
(Authenticated sender: luke-jr)
by zinan.dashjr.org (Postfix) with ESMTPSA id 7997938A2C94;
Fri, 26 Feb 2016 02:35:25 +0000 (UTC)
X-Hashcash: 1:25:160226:bitcoin-dev@lists.linuxfoundation.org::YQZqlp3cn848DFNm:pvrL
X-Hashcash: 1:25:160226:joseph@lightning.network::z03/kUSthjQPnem3:Qg0=
From: Luke Dashjr <luke@dashjr.org>
To: bitcoin-dev@lists.linuxfoundation.org,
Joseph Poon <joseph@lightning.network>
Date: Fri, 26 Feb 2016 02:35:23 +0000
User-Agent: KMail/1.13.7 (Linux/4.1.18-gentoo; KDE/4.14.8; x86_64; ; )
References: <20160226010746.GB10295@lightning.network>
In-Reply-To: <20160226010746.GB10295@lightning.network>
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="iso-8859-1"
Content-Transfer-Encoding: 7bit
Message-Id: <201602260235.24687.luke@dashjr.org>
X-Spam-Status: No, score=-1.8 required=5.0 tests=BAYES_00,RCVD_IN_SBL
autolearn=no version=3.3.1
X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on
smtp1.linux-foundation.org
Subject: Re: [bitcoin-dev] SIGHASH_NOINPUT in Segregated Witness
X-BeenThere: bitcoin-dev@lists.linuxfoundation.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Bitcoin Development 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: Fri, 26 Feb 2016 02:35:36 -0000
On Friday, February 26, 2016 1:07:46 AM Joseph Poon via bitcoin-dev wrote:
> This would be achieved using a SIGHASH flag, termed SIGHASH_NOINPUT. It
> does not include as part of the signature, the outpoint being spent
> (txid and index), nor the amount. It however, would include the spent
> outpoint's script as part of the signature. Note that this is just a
> SIGHASH flag, and the outpoints are still being included as part of the
> txins (if they are mutated, the new txids can be updated by the wallet
> without resigning). This allows for a signature to apply to anything
> with that pubkey (therefore pubkeys with this flag should not be
> reused).
I'd like this regardless of Lightning, as it makes it possible to write fully
malleability-proof wallet software also.
> For safety, this only applies in SegWit transactions, as segwit
> provides a sufficient malleability solution, there is no incentive to
> improperly use this sighash flag as a roundabout way to resolve
> malleability.
SegWit's malleability solution is not really sufficient in comparison, but I
don't think there's a need to make this available to pre-SegWit transactions
anyway (and doing so would probably complicate it).
Luke
|