summaryrefslogtreecommitdiff
path: root/ec/be4d881bef59666f9e0328e40ca7df7c661ad1
blob: 4f4d4ceb92659b1a1d2185d1b79267da5a69678b (plain)
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
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
Return-Path: <user@petertodd.org>
Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org
	[172.17.192.35])
	by mail.linuxfoundation.org (Postfix) with ESMTPS id 9244A49F;
	Sat,  5 Oct 2019 15:49:09 +0000 (UTC)
X-Greylist: from auto-whitelisted by SQLgrey-1.7.6
X-Greylist: from auto-whitelisted by SQLgrey-1.7.6
Received: from outmail148095.authsmtp.com (outmail148095.authsmtp.com
	[62.13.148.95])
	by smtp1.linuxfoundation.org (Postfix) with ESMTPS id E55E3709;
	Sat,  5 Oct 2019 15:49:08 +0000 (UTC)
Received: from mail-c233.authsmtp.com (mail-c233.authsmtp.com [62.13.128.233])
	by punt16.authsmtp.com. (8.15.2/8.15.2) with ESMTP id x95Fn73q059803;
	Sat, 5 Oct 2019 16:49:07 +0100 (BST)
	(envelope-from user@petertodd.org)
Received: from petertodd.org (ec2-52-5-185-120.compute-1.amazonaws.com
	[52.5.185.120]) (authenticated bits=0)
	by mail.authsmtp.com (8.15.2/8.15.2) with ESMTPSA id x95Fn5p6026608
	(version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO);
	Sat, 5 Oct 2019 16:49:06 +0100 (BST)
	(envelope-from user@petertodd.org)
Received: from [127.0.0.1] (localhost [127.0.0.1])
	by petertodd.org (Postfix) with ESMTPSA id A090340160;
	Sat,  5 Oct 2019 15:49:04 +0000 (UTC)
Received: by localhost (Postfix, from userid 1000)
	id 7516D1FF74; Sat,  5 Oct 2019 11:49:02 -0400 (EDT)
Date: Sat, 5 Oct 2019 11:49:02 -0400
From: Peter Todd <pete@petertodd.org>
To: Jeremy <jlrubin@mit.edu>
Message-ID: <20191005154902.ck236q65xha25ore@petertodd.org>
References: <87wodp7w9f.fsf@gmail.com>
	<20191001155929.e2yznsetqesx2jxo@erisian.com.au>
	<CR-etCjXB-JWkvecjDog4Pkq1SuLUgndtSrZo-V4f4EGcNXzNCeAHRvCZGrxDWw7aHVdDY0pAF92jNLb_Hct0bMb3ew6JEpB9AfIm1tSGaQ=@protonmail.com>
	<CAEM=y+XbP3Dn7X8rHu7h0vbX6DkKA0vFK5nQqzcJ_V+D4EVMmw@mail.gmail.com>
	<C1OLL5FLxdOgfQ_A15mf88wIyztDapkyXJ2HZ0HxwmQADhRXGRe3le7Veso4tMIlbis6I0qiCd22xug5_GCKtgrjGnBtojWxOCMgn1UldkE=@protonmail.com>
	<CAEM=y+WCGSF_=WXpgXJUZCZcGUQhxzXF6Wv1_iX+VwEyYSWypg@mail.gmail.com>
	<CAD5xwhi7=5eiv1jjf72-rUezZMfj3caR+PGfZEa8i8rjNjodFg@mail.gmail.com>
	<20191004111536.w7snbgpoe27xutfu@petertodd.org>
	<CAD5xwhhLd9Ufv50kOi+yaJ5dTX9LhB1dPsK_0bqjz038tChcjw@mail.gmail.com>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha256;
	protocol="application/pgp-signature"; boundary="as5ahu4hs27l4qst"
Content-Disposition: inline
In-Reply-To: <CAD5xwhhLd9Ufv50kOi+yaJ5dTX9LhB1dPsK_0bqjz038tChcjw@mail.gmail.com>
User-Agent: NeoMutt/20170113 (1.7.2)
X-Server-Quench: a9a5c4df-e787-11e9-8757-84349711df28
X-AuthReport-Spam: If SPAM / abuse - report it at:
	http://www.authsmtp.com/abuse
X-AuthRoute: OCd2Yg0TA1ZIVwkA IjsJECJaVQIpKltL GxAVKBZePFsRUQkR
	aQdMdgcUF1YAAgsB Am8bWlJeVFR7WWU7 bghPaBtcak9QXgdq
	T0pMXVMcXAxtd0IE RhgeUB90dw0IeX53 Y0csD3kKWRd+IRBg
	F0lcEnAHZDJpdWgY VUdFfwdXdApNfx4R PFJ3GhFYa3VsGiM3
	HxM1PjY+eDlSNhEd cQsMMVkVQEBOEjMi clglJQIENHFNWCwo
	ZyYreBY3G0ANM0Mv MF0uEU4YPn1aBgxF FFxWGy5eIREITS02
	EUtcWk8YCCBBCWAU Cxs5OgVFHDtPRkIA 
X-Authentic-SMTP: 61633532353630.1021:706
X-AuthFastPath: 0 (Was 255)
X-AuthSMTP-Origin: 52.5.185.120/25
X-AuthVirus-Status: No virus detected - but ensure you scan with your own
	anti-virus system.
X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_LOW
	autolearn=ham version=3.3.1
X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on
	smtp1.linux-foundation.org
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>,
	"lightning-dev@lists.linuxfoundation.org"
	<lightning-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] [Lightning-dev] OP_CAT was Re: Continuing the
 discussion about noinput / anyprevout
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: Sat, 05 Oct 2019 15:49:09 -0000


--as5ahu4hs27l4qst
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Fri, Oct 04, 2019 at 11:40:53AM -0700, Jeremy wrote:
> Interesting point.
>=20
> The script is under your control, so you should be able to ensure that you
> are always using a correctly constructed midstate, e.g., something like:
>=20
> scriptPubKey: <-1> OP_SHA256STREAM DEPTH OP_SHA256STREAM <-2>
> OP_SHA256STREAM
> <hash> OP_EQUALVERIFY
>=20
> would hash all the elements on the stack and compare to a known hash.
> How is that sort of thing weak to midstateattacks?

Obviously with care you can get the computation right. But at that point wh=
at's
the actual advantage over OP_CAT?

We're limited by the size of the script anyway; if the OP_CAT output size l=
imit
is comparable to that for almost anything you could use SHA256STREAM on you
could just as easily use OP_CAT, followed by a single OP_SHA256.

--=20
https://petertodd.org 'peter'[:-1]@petertodd.org

--as5ahu4hs27l4qst
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----
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=Fr7x
-----END PGP SIGNATURE-----

--as5ahu4hs27l4qst--