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
|
Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192]
helo=mx.sourceforge.net)
by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76)
(envelope-from <bip@mattwhitlock.name>) id 1WW9FN-0006I1-RJ
for bitcoin-development@lists.sourceforge.net;
Fri, 04 Apr 2014 18:53:49 +0000
X-ACL-Warn:
Received: from qmta07.westchester.pa.mail.comcast.net ([76.96.62.64])
by sog-mx-2.v43.ch3.sourceforge.com with esmtp (Exim 4.76)
id 1WW9FM-0006Mv-5B for bitcoin-development@lists.sourceforge.net;
Fri, 04 Apr 2014 18:53:49 +0000
Received: from omta22.westchester.pa.mail.comcast.net ([76.96.62.73])
by qmta07.westchester.pa.mail.comcast.net with comcast
id ltk31n0051ap0As57utitG; Fri, 04 Apr 2014 18:53:42 +0000
Received: from crushinator.localnet ([IPv6:2601:6:4800:47f:219:d1ff:fe75:dc2f])
by omta22.westchester.pa.mail.comcast.net with comcast
id luth1n00n4VnV2P3iuti9S; Fri, 04 Apr 2014 18:53:42 +0000
From: Matt Whitlock <bip@mattwhitlock.name>
To: Gregory Maxwell <gmaxwell@gmail.com>
Date: Fri, 04 Apr 2014 14:53:41 -0400
Message-ID: <3723626.oQyno8ZOTj@crushinator>
User-Agent: KMail/4.12.4 (Linux/3.12.13-gentoo; KDE/4.12.4; x86_64; ; )
In-Reply-To: <CAAS2fgT=n48F9=Yk9k1Vu3_8nsExAjaHYbUeW60q2bMN1pi-qA@mail.gmail.com>
References: <CAC7yFxSE8-TWPN-kuFiqdPKMDuprbiVJi7-z-ym+AUyA_f-xJw@mail.gmail.com>
<60732286.zdbbI6td0e@crushinator>
<CAAS2fgT=n48F9=Yk9k1Vu3_8nsExAjaHYbUeW60q2bMN1pi-qA@mail.gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 7Bit
Content-Type: text/plain; charset="us-ascii"
X-Spam-Score: 4.0 (++++)
X-Spam-Report: Spam Filtering performed by mx.sourceforge.net.
See http://spamassassin.org/tag/ for more details.
4.0 HK_SCAM_N2 BODY: HK_SCAM_N2
-0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/,
no trust [76.96.62.64 listed in list.dnswl.org]
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: 1WW9FM-0006Mv-5B
Cc: bitcoin-development <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] Presenting a BIP for Shamir's Secret
Sharing of Bitcoin private keys
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: Fri, 04 Apr 2014 18:53:50 -0000
On Friday, 4 April 2014, at 10:51 am, Gregory Maxwell wrote:
> On Fri, Apr 4, 2014 at 10:16 AM, Matt Whitlock <bip@mattwhitlock.name> wrote:
> > Honestly, that sounds a lot more complicated than what I have now. I made my current implementation because I just wanted something simple that would let me divide a private key into shares for purposes of dissemination to my next of kin et al.
>
> I suggest you go look at some of the other secret sharing
> implementations that use GF(2^8), they end up just being a couple of
> dozen lines of code. Pretty simple stuff, and they work efficiently
> for all sizes of data, there are implementations in a multitude of
> languages. There are a whole bunch of these.
Okay, I will.
> > Do you have a use case in mind that would benefit from byte-wise operations rather than big-integer operations? I mean, I guess if you were trying to implement this BIP on a PIC microcontroller, it might be nice to process the secret in smaller bites. (No pun intended.) But I get this feeling that you're only pushing me away from the present incarnation of my proposal because you think it's too similar (but not quite similar enough) to a threshold ECDSA key scheme.
>
> It lets you efficiently scale to any size data being encoded without
> extra overhead or having additional primes. It can be compactly
> implemented in Javascript (there are several implementations you can
> find if you google), it shouldn't be burdensome to implement on a
> device like a trezor (much less a real microcontroller).
Those are fair points.
> And yea, sure, it's distinct from the implementation you'd use for
> threshold signing. A threshold singing one would lack the size agility
> or the easy of implementation on limited devices. So I do think that
> if there is to be two it would be good to gain the advantages that
> can't be achieved in an threshold ECDSA compatible approach.
I agree. I'll look into secret sharing in GF(2^8), but it may take me a few days.
|
