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
|
Return-Path: <eric@voskuil.org>
Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org
[172.17.192.35])
by mail.linuxfoundation.org (Postfix) with ESMTPS id 02ECF9EB
for <bitcoin-dev@lists.linuxfoundation.org>;
Tue, 28 Jun 2016 20:29:59 +0000 (UTC)
X-Greylist: whitelisted by SQLgrey-1.7.6
Received: from mail-wm0-f46.google.com (mail-wm0-f46.google.com [74.125.82.46])
by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 2FAED1FE
for <bitcoin-dev@lists.linuxfoundation.org>;
Tue, 28 Jun 2016 20:29:58 +0000 (UTC)
Received: by mail-wm0-f46.google.com with SMTP id a66so44122679wme.0
for <bitcoin-dev@lists.linuxfoundation.org>;
Tue, 28 Jun 2016 13:29:58 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=voskuil-org.20150623.gappssmtp.com; s=20150623;
h=mime-version:subject:from:in-reply-to:date:cc
:content-transfer-encoding:message-id:references:to;
bh=GPngk4K78dRiDVbpHCReP61E8+fER4y6+Y7Cf5x6wvY=;
b=wp9lFN0oDslJ4mVvCemm9j3cdYh/TwqFEDQbjyr0Q/HHDQiSyykc0brYCbaFsN529e
tPqB8cZoGyGAX8qS7wLNnh/6w8MzQtMrJLpxXLUTvJrQWhV3F3VBPtIBL5Q+4CdiCMuX
CmtTCjeAkrNQcM56U6HRmIlDerzE183lrKplVfzysibA9zsCRvTDpa7ri3A0H3dLwyn1
7yzNf4IujFz/k/130xmbOkSbdvgk4c3HUBNy7mQNdxA3zEL1LMk1UOS/MYf2p31FkVQo
sL2qJQ/iYZ5uQ/KBpOqypiSlf04SJsh9OPJi8D5f4GnzzSEKSSVFgx1237jhhmLH4xts
sKFg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=1e100.net; s=20130820;
h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc
:content-transfer-encoding:message-id:references:to;
bh=GPngk4K78dRiDVbpHCReP61E8+fER4y6+Y7Cf5x6wvY=;
b=U5YZFcl/VzgRKXIlp0cXD0LkmdkkHTDbT5NxWdnFQ0jEr8WooARkbtDC0mGS6D9kMu
FzZKC9Y/+yPwKVZYipK25araUswEa+HlkmBjA6sE9YDEEJ6xSnGjf36WWbk8e6zsnfVe
WBOrAci4eiIMO1zFTak9FFcFgFgOURjzNoHan6/R5pu4Hf3+NglRAzEa9GAp6bsMfMj0
lV+bFms3SuEfM1zrRjHExlRwNsw63v17v94Up1m9qRhqYltThDV+HLsxokI6KDESM8an
hzxBuffYs0xJQR0KvRJVSP2HyssGf+Jemt9nqOsFhaQ1Jn69vl5Uu8z1272Hk2ttSMHA
+uPA==
X-Gm-Message-State: ALyK8tJkg4ATl+S1rRLFcVCgSimW0DfeL1lUCJpgijIg1tBZwAwWOy1QQI+GF+5HlXMChw==
X-Received: by 10.194.190.163 with SMTP id gr3mr4766328wjc.148.1467145796752;
Tue, 28 Jun 2016 13:29:56 -0700 (PDT)
Received: from [10.114.7.71] ([41.33.219.254])
by smtp.gmail.com with ESMTPSA id r6sm609461wme.14.2016.06.28.13.29.55
(version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128);
Tue, 28 Jun 2016 13:29:55 -0700 (PDT)
Content-Type: text/plain;
charset=us-ascii
Mime-Version: 1.0 (1.0)
From: Eric Voskuil <eric@voskuil.org>
X-Mailer: iPhone Mail (13F69)
In-Reply-To: <20160628201447.GA1148@fedora-21-dvm>
Date: Tue, 28 Jun 2016 22:29:54 +0200
Content-Transfer-Encoding: quoted-printable
Message-Id: <4DCF7DD2-6533-4F79-8CA1-871B67C01BDA@voskuil.org>
References: <87h9cecad5.fsf@rustcorp.com.au>
<1E86A00F-0609-4DBC-9543-94AE04CC13C9@voskuil.org>
<577234A4.3030808@jonasschnelli.ch>
<360EF9B8-A174-41CA-AFDD-2BC2C0B4DECB@voskuil.org>
<20160628182202.GA5519@fedora-21-dvm>
<D40F9E9D-DB6C-4083-A9E8-C5EBC363DB30@voskuil.org>
<20160628201447.GA1148@fedora-21-dvm>
To: Peter Todd <pete@petertodd.org>
X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,DKIM_SIGNED,
DKIM_VALID, MIME_QP_LONG_LINE,
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>
Subject: Re: [bitcoin-dev] BIP 151
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: Tue, 28 Jun 2016 20:29:59 -0000
> On Jun 28, 2016, at 10:14 PM, Peter Todd <pete@petertodd.org> wrote:
>=20
>> On Tue, Jun 28, 2016 at 08:35:26PM +0200, Eric Voskuil wrote:
>> Hi Peter,
>>=20
>> What in this BIP makes a MITM attack easier (or easy) to detect, or incre=
ases the probability of one being detected?
>=20
> BIP151 gives users the tools to detect a MITM attack.
>=20
> It's kinda like PGP in that way: lots of PGP users don't properly check ke=
ys,
PGP requires a secure side channel for transmission of public keys. How does=
one "check" a key of an anonymous peer? I know you well enough to know you w=
ouldn't trust a PGP key received over an insecure channel.
All you can prove is that you are talking to a peer and that communications i=
n the session remain with that peer. The peer can be the attacker. As Jonas h=
as acknowledged, authentication is required to actually guard against MITM a=
ttacks.
> so an attacker won't have a hard time MITM attacking those users. But some=
> users do check keys, a labor intensive manual process, but not a process t=
hat
> requires any real cryptographic sophistication, let alone writing any code=
.
> It's very difficult for widescale attackers to distinguish the users who d=
o
> check keys from the ones that don't, so if you MITM attack _any_ user you r=
un
> the risk of running into one of the few that does check, and those users c=
an
> alert everyone else.
>=20
> The key thing, is we need to get everyones communications encrypted first:=
if
> we don't the MITM attacker can intercept 99% of the communications with 0%=
risk
> of detection, because the non-sophisticated users are trivially distinguis=
hable from the sophisticated users: just find the users with unencrypted
> communications!
>=20
> --=20
> https://petertodd.org 'peter'[:-1]@petertodd.org
|
