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
136
137
138
|
Return-Path: <nadahalli@gmail.com>
Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137])
by lists.linuxfoundation.org (Postfix) with ESMTP id 1B44FC016E
for <bitcoin-dev@lists.linuxfoundation.org>;
Mon, 29 Jun 2020 11:58:04 +0000 (UTC)
Received: from localhost (localhost [127.0.0.1])
by fraxinus.osuosl.org (Postfix) with ESMTP id 0893F86EFE
for <bitcoin-dev@lists.linuxfoundation.org>;
Mon, 29 Jun 2020 11:58:04 +0000 (UTC)
X-Virus-Scanned: amavisd-new at osuosl.org
Received: from fraxinus.osuosl.org ([127.0.0.1])
by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024)
with ESMTP id 2VNFOGTq9Xj1
for <bitcoin-dev@lists.linuxfoundation.org>;
Mon, 29 Jun 2020 11:58:03 +0000 (UTC)
X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6
Received: from mail-pf1-f170.google.com (mail-pf1-f170.google.com
[209.85.210.170])
by fraxinus.osuosl.org (Postfix) with ESMTPS id 6A70F8575E
for <bitcoin-dev@lists.linuxfoundation.org>;
Mon, 29 Jun 2020 11:58:03 +0000 (UTC)
Received: by mail-pf1-f170.google.com with SMTP id 207so7625473pfu.3
for <bitcoin-dev@lists.linuxfoundation.org>;
Mon, 29 Jun 2020 04:58:03 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025;
h=mime-version:references:in-reply-to:from:date:message-id:subject:to
:cc; bh=pCyRLgGW9JnDd+FAp5L9wcw6i/0iaTn6NzOBd/jVqao=;
b=OOrK7MPW10dkXgAIIbjyIeUZ06eQTYp+Fy7MKZZkAU45aYY4Hn8ZeL1kMlP/iBUK1Q
w6MFQb5YMy/S094v/qrw6Sk4hHmvnNZIqPNDrAME1NyRdTqGyQ2L8KmbpRAmoCMuZlHY
iXLjLSDt78+MRDcQvXaSlLqauinZA6OwVwt6rZMboCGafGqpkxhxuaEfgfBRj76A8TrW
XA5iUzl8v3cVYM7FPhmGwQxgTyQj+QL0iWWLrfXDzB/YvBrKhrvBSucequu/fpKph7NM
Wbwwode/8LjXPCEFdxQw0WpquKnKmO1rc3KaFJmuD5UJ/A7xnWXyqRcResvoJH+cFiTf
eSfg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=1e100.net; s=20161025;
h=x-gm-message-state:mime-version:references:in-reply-to:from:date
:message-id:subject:to:cc;
bh=pCyRLgGW9JnDd+FAp5L9wcw6i/0iaTn6NzOBd/jVqao=;
b=idu2Bl1k70DlcB32HU06zoeyMIA2RfYnXcEGylZzZRbkk2sXgwn1U0ft1QbnasqehC
FRfdYB1JBq+Pp31yPT7Ohg3OyqbxnTwqc/1QOUNxa/+40SlzoG0iXlMEUsI/sr+q752E
pJZ5+RxAYsHenSKnrH8cslxsPJYJ4qxWcH3JfjsS6QI1+rz2wyWvX3zASgMNGwHRyRbS
JOnS+wMA+dx7K6U84jwjV7/qXyAq4F3egjCfdxBWdAnEDEgtlbfUE6yob1ayqy18aKZB
qy3CcWclGW/TesxQuSI3zRmMAfAGP79XUimcsLoQ8lNF7l+/bsEFPNoly1gc21tWFuYf
xhfg==
X-Gm-Message-State: AOAM530LWIySNGS1dhSmL7PvsPHBkAsT3sVvTEXkrppdM4huwmW4Fy/0
NJFcxk4aZTAiKzuhlcMz+uCab2ygK+LaTrIa4nY=
X-Google-Smtp-Source: ABdhPJwoP0Hve8sBdvC3LpcUxJ+2XknIy4dN38pN1cAOesCvANbpR81uJQEmszMw3o+X6lwhGHC+EE03TVIJy2+fRMg=
X-Received: by 2002:a63:5a54:: with SMTP id k20mr9893221pgm.226.1593431882939;
Mon, 29 Jun 2020 04:58:02 -0700 (PDT)
MIME-Version: 1.0
References: <CABT1wW=X35HRVGuP-BHUhDrkBEw27+-iDkNnHWjRU-1mRkn0JQ@mail.gmail.com>
<CABT1wW=KWtoo6zHs8=yUQ7vAYcFSdAzdpDJ9yfw6sJrLd6dN5A@mail.gmail.com>
<20200628121517.f3l2mjcy7x4566v3@ganymede>
In-Reply-To: <20200628121517.f3l2mjcy7x4566v3@ganymede>
From: Tejaswi Nadahalli <nadahalli@gmail.com>
Date: Mon, 29 Jun 2020 13:57:52 +0200
Message-ID: <CAAifmAS6jX5f4XThSw_ygFpCU7JVdmQSgVjOj+if3p4qeO8sNg@mail.gmail.com>
To: "David A. Harding" <dave@dtrt.org>,
Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Content-Type: multipart/alternative; boundary="0000000000005b415505a937c5a5"
X-Mailman-Approved-At: Mon, 29 Jun 2020 12:24:33 +0000
Cc: Matan Yehieli <matany@campus.technion.ac.il>,
Itay Tsabary <sitay@campus.technion.ac.il>
Subject: Re: [bitcoin-dev] MAD-HTLC
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: Mon, 29 Jun 2020 11:58:04 -0000
--0000000000005b415505a937c5a5
Content-Type: text/plain; charset="UTF-8"
On Sun, Jun 28, 2020 at 2:16 PM David A. Harding via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:
> So, if I understand correctly, even a small amount of "myopic" hashrate
> and long timeouts---or modest amounts of hashrate and short
> timeouts---makes this attack unlikely to succeed (and, even in the cases
> where it does succeed, Bob will have to offer a very large bribe to
> compensate "rational" miners for their high chance of losing out on
> gaining any transaction fees).
>
We were separately working on a similar problem, and wrote a paper as well:
https://eprint.iacr.org/2020/774 *
We look at the Alice's-Fees/Bob's-Bribe ratio. We also look at "strong" and
"weak" miners in this context. If a miner is weak, their hash-rate is lower
than this fees/bribe ratio. If they are strong, their hash rate is more
than this fees/bribe ratio. In this setting, it turns out that if there are
only strong miners, Bob will win. If there is at least one weak miner,
Alice has to win, given a reasonable timeout value. We found it awesome
that lightning has a parameter called "channel-reserve_satoshis", which
directly helps in countering this bribe by giving Alice some leeway in fees.
* Ph.D students want to write papers, unfortunately.
--0000000000005b415505a937c5a5
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
<div dir=3D"ltr"><div dir=3D"ltr"><span class=3D"gmail-im" style=3D"color:r=
gb(80,0,80)"><div dir=3D"ltr" class=3D"gmail_attr">On Sun, Jun 28, 2020 at =
2:16 PM David A. Harding via bitcoin-dev <<a href=3D"mailto:bitcoin-dev@=
lists.linuxfoundation.org" target=3D"_blank">bitcoin-dev@lists.linuxfoundat=
ion.org</a>> wrote:<br></div><blockquote class=3D"gmail_quote" style=3D"=
margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-lef=
t:1ex">So, if I understand correctly, even a small amount of "myopic&q=
uot; hashrate<br>and long timeouts---or modest amounts of hashrate and shor=
t<br>timeouts---makes this attack unlikely to succeed (and, even in the cas=
es<br>where it does succeed, Bob will have to offer a very large bribe to<b=
r>compensate "rational" miners for their high chance of losing ou=
t on<br>gaining any transaction fees).<br></blockquote><div><br></div></spa=
n><div>We were separately working on a similar problem, and wrote a paper a=
s well:=C2=A0<a href=3D"https://eprint.iacr.org/2020/774" target=3D"_blank"=
>https://eprint.iacr.org/2020/774</a>=C2=A0*<div><br></div><div>We look at =
the Alice's-Fees/Bob's-Bribe ratio. We also look at "strong&qu=
ot; and "weak" miners in this context. If a miner is weak, their =
hash-rate is lower than this fees/bribe ratio. If they are strong, their ha=
sh rate is more than this fees/bribe ratio. In this setting, it turns out t=
hat if there are only=C2=A0strong miners, Bob will win. If there is at leas=
t one weak miner, Alice has to win, given a reasonable timeout value. We fo=
und it awesome that lightning=C2=A0has a parameter called "channel-res=
erve_satoshis", which directly helps in countering this bribe by givin=
g Alice some leeway in fees.</div><div><div><div><br></div><div>* Ph.D stud=
ents=C2=A0want to write papers, unfortunately.</div></div></div></div></div=
></div>
--0000000000005b415505a937c5a5--
|
