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
|
Received: from sog-mx-1.v43.ch3.sourceforge.com ([172.29.43.191]
helo=mx.sourceforge.net)
by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76)
(envelope-from <jeremy@taplink.co>) id 1W4fKG-0008BC-6L
for bitcoin-development@lists.sourceforge.net;
Sat, 18 Jan 2014 23:29:16 +0000
Received-SPF: pass (sog-mx-1.v43.ch3.sourceforge.com: domain of taplink.co
designates 50.117.27.232 as permitted sender)
client-ip=50.117.27.232; envelope-from=jeremy@taplink.co;
helo=mail.taplink.co;
Received: from mail.taplink.co ([50.117.27.232])
by sog-mx-1.v43.ch3.sourceforge.com with smtp (Exim 4.76)
id 1W4fKF-0003BF-1A for bitcoin-development@lists.sourceforge.net;
Sat, 18 Jan 2014 23:29:15 +0000
Received: from [10.115.119.149] ([166.147.71.166]) by mail.taplink.co ;
Sat, 18 Jan 2014 15:24:10 -0800
References: <CANEZrP1KAVhi_-cxCYe0rR9LUSYJ8MyW8=6eSJZ65FeY5ZJNuQ@mail.gmail.com>
<20140114225321.GT38964@giles.gnomon.org.uk>
<CANAnSg0tH_bK_19rsRRHOeZgrGYeWMhW89fXPyS4DQGmS4r_7A@mail.gmail.com>
<CALimQCXgc0eXeOcqFGUaCpSF7gKEe87KzvLqHZwUysV3WyjjGw@mail.gmail.com>
<CAAS2fgShChAQryfUOBp60jB-zxn2tH986fu1HfT+LsNdBYnoYg@mail.gmail.com>
<CAJHLa0P5r2+kxy7w8G=h=TAhdk1jUoW5UOiv-euo47uQY0u9ZA@mail.gmail.com>
<op.w9q6jdsayldrnw@laptop-air.hsd1.ca.comcast.net>
<20140116212805.GA4421@petertodd.org>
<CANAnSg2TY7Zh7RnHkBeTz1s-WutGLayum8q5DhdLhtOBMDT9ng@mail.gmail.com>
<CANEZrP1=PMiJn9BoN50K1wz2tOdxx5L80ngjErCJqj5wm2ESPA@mail.gmail.com>
<20140117144601.GA8614@petertodd.org>
<CALimQCU10asn65q=+VwCVNtgbROu9XQOYKzB7jy-TCFoemjEOQ@mail.gmail.com>
<52DA093D.4070505@gmail.com>
<CAAS2fgSdLXfKgbC+MtsiXdp9o7BNp1pc1p_G511LrgwOzGNZFg@mail.gmail.com>
Mime-Version: 1.0 (1.0)
In-Reply-To: <CAAS2fgSdLXfKgbC+MtsiXdp9o7BNp1pc1p_G511LrgwOzGNZFg@mail.gmail.com>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: quoted-printable
Message-Id: <52F8B4EC-F955-46E4-B871-3BEEFF69907D@taplink.co>
X-Mailer: iPhone Mail (10B146)
From: Jeremy Spilman <jeremy@taplink.co>
Date: Sat, 18 Jan 2014 17:12:58 -0600
To: Gregory Maxwell <gmaxwell@gmail.com>
oclient: 166.147.71.166#jeremy@taplink.co#465
X-Spam-Score: -2.0 (--)
X-Spam-Report: Spam Filtering performed by mx.sourceforge.net.
See http://spamassassin.org/tag/ for more details.
-1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for
sender-domain
-0.0 SPF_PASS SPF: sender matches SPF record
-0.4 RP_MATCHES_RCVD Envelope sender domain matches handover relay
domain
-0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from
author's domain
0.1 DKIM_SIGNED Message has a DKIM or DK signature,
not necessarily valid
-0.1 DKIM_VALID Message has at least one valid DKIM or DK signature
X-Headers-End: 1W4fKF-0003BF-1A
Cc: Bitcoin Development <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] Stealth Addresses
X-BeenThere: bitcoin-development@lists.sourceforge.net
X-Mailman-Version: 2.1.9
Precedence: list
List-Id: <bitcoin-development.lists.sourceforge.net>
List-Unsubscribe: <https://lists.sourceforge.net/lists/listinfo/bitcoin-development>,
<mailto:bitcoin-development-request@lists.sourceforge.net?subject=unsubscribe>
List-Archive: <http://sourceforge.net/mailarchive/forum.php?forum_name=bitcoin-development>
List-Post: <mailto:bitcoin-development@lists.sourceforge.net>
List-Help: <mailto:bitcoin-development-request@lists.sourceforge.net?subject=help>
List-Subscribe: <https://lists.sourceforge.net/lists/listinfo/bitcoin-development>,
<mailto:bitcoin-development-request@lists.sourceforge.net?subject=subscribe>
X-List-Received-Date: Sat, 18 Jan 2014 23:29:16 -0000
> On Fri, Jan 17, 2014 at 8:55 PM, Alan Reiner <etotheipi@gmail.com> wrote:
>> Isn't there a much faster asymmetric scheme that we can use? I've heard p=
eople talk about ed25519, though I'm not sure it can be used for encryption.=
>=20
> Doing ECDH with our curve is within a factor of ~2 of the fastest
> encryption available at this security level, AFAIK. And separate
> encryption would ~double the amount of data vs using the ephemeral key
> for derivation.
>=20
> Using another cryptosystem would mandate carry around additional code
> for a fast implementation of that cryptosystem, which wouldn't be
> fantastic.
>=20
> So I'm not sure much can be improved there.
In the case where payment is being sent only to Q1, and Q2 is for discovery o=
nly, perhaps we could use a 160-bit curve for d2/Q2 and e/P resulting in 20 b=
yte vs 32 bytes in the OP_RETURN, and of course faster multiplication.=20
80-bits of security I assume still greatly exceeds the actual level of priva=
cy you get with the overall solution, and since Q2 is never protecting actua=
l funds...
But if it's a "real weakening" of the privacy then definitely not worth it, a=
nd even the added complexity of another curve seems possibly not worth it...=
|
