From: Matt Whitlock <bip@mattwhitlock•name>
To: Alan Reiner <etotheipi@gmail•com>
Cc: bitcoin-development@lists•sourceforge.net
Subject: Re: [Bitcoin-development] Presenting a BIP for Shamir's Secret Sharing of Bitcoin private keys
Date: Sat, 29 Mar 2014 14:00:15 -0400 [thread overview]
Message-ID: <2135731.4HGHfZWzo5@crushinator> (raw)
In-Reply-To: <53370854.5050303@gmail.com>
On Saturday, 29 March 2014, at 1:52 pm, Alan Reiner wrote:
> On 03/29/2014 01:19 PM, Matt Whitlock wrote:
> > I intentionally omitted the parameter M (minimum subset size) from the shares because including it would give an adversary a vital piece of information. Likewise, including any kind of information that would allow a determination of whether the secret has been correctly reconstituted would give an adversary too much information. Failing silently when given incorrect shares or an insufficient number of shares is intentional.
>
> I do not believe this is a good tradeoff. It's basically obfuscation of
> something that is already considered secure at the expense of
> usability. It's much more important to me that the user understands
> what is in their hands (or their family members after they get hit by a
> bus), than to obfuscate the parameters of the secret sharing to provide
> a tiny disadvantage to an adversary who gets ahold of one.
>
> The fact that it fails silently is really all downside, not a benefit.
> If I have enough fragments, I can reconstruct the seed and see that it
> produces addresses with money. If not, I know I need more fragments.
> I'm much more concerned about my family having all the info they need to
> recover the money, than an attacker knowing that he needs two more
> fragments instead of which are well-secured anyway.
For what it's worth, ssss also omits from the shares any information about the threshold. It will happily return a garbage secret if too few shares are combined. (And actually, it will happily return a garbage secret if too *many* shares are combined, too. My implementation does not have that problem.)
next prev parent reply other threads:[~2014-03-29 18:00 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CACsn0ckScTWG4YxNCscxvtdsmcUkxtR2Gi-rdBs2HCkirPz5rA@mail.gmail.com>
2014-03-29 15:44 ` Matt Whitlock
2014-03-29 16:59 ` Alan Reiner
2014-03-29 17:19 ` Matt Whitlock
2014-03-29 17:52 ` Alan Reiner
2014-03-29 18:00 ` Matt Whitlock [this message]
2014-03-29 18:08 ` Alan Reiner
2014-03-29 18:10 ` Matt Whitlock
[not found] ` <CAAt2M18j7bGDsKouVw+e4j+FMiJ4vK6-sx+nrkwHyiKLqiH7Jg@mail.gmail.com>
2014-03-29 19:34 ` Natanael
2014-04-04 2:38 ` Jeff Garzik
2014-03-29 18:16 ` Tamas Blummer
2014-03-29 18:41 ` Alan Reiner
2014-03-29 17:28 ` Roy Badami
2014-03-29 17:42 ` Matt Whitlock
2014-03-29 17:51 ` Roy Badami
2014-03-29 17:28 ` devrandom
[not found] ` <1396113933.8809.91.camel@mimiz>
2014-03-29 17:38 ` Matt Whitlock
2014-03-29 17:46 ` Gregory Maxwell
2014-03-29 19:49 ` Tamas Blummer
2014-03-29 17:48 ` devrandom
2014-03-29 17:51 ` Matt Whitlock
2014-03-29 17:56 ` devrandom
2014-04-03 12:41 Nikita Schmidt
2014-04-03 21:42 ` Matt Whitlock
2014-04-04 13:51 ` Nikita Schmidt
2014-04-04 14:14 ` Gregory Maxwell
2014-04-04 16:05 ` Matt Whitlock
2014-04-04 16:25 ` Gregory Maxwell
2014-04-04 16:36 ` Matt Whitlock
2014-04-04 17:08 ` Gregory Maxwell
2014-04-04 17:16 ` Matt Whitlock
2014-04-04 17:51 ` Gregory Maxwell
2014-04-04 18:53 ` Matt Whitlock
2014-04-04 16:03 ` Matt Whitlock
2014-04-08 0:33 ` Nikita Schmidt
2014-04-08 0:38 ` Gregory Maxwell
2014-04-08 1:46 ` Matt Whitlock
2014-04-08 2:07 ` Gregory Maxwell
2014-04-08 11:52 ` Matt Whitlock
2014-04-10 22:31 ` Nikita Schmidt
2014-04-22 8:06 ` Jan Møller
2014-04-22 8:11 ` Matt Whitlock
2014-04-22 8:27 ` Jan Møller
2014-04-22 8:29 ` Matt Whitlock
2014-04-22 8:39 ` Jan Møller
2014-04-22 8:43 ` Matt Whitlock
2014-04-22 8:51 ` Jan Møller
2014-04-22 9:13 ` Matt Whitlock
2014-04-22 11:50 ` Justin A
2014-04-22 8:35 ` Matt Whitlock
2014-04-22 8:39 ` Tamas Blummer
2014-04-22 8:40 ` Matt Whitlock
2014-04-22 8:43 ` Tamas Blummer
2014-04-22 8:47 ` Matt Whitlock
2014-04-22 8:50 ` Tamas Blummer
2014-04-22 15:32 ` Mark Friedenbach
2014-04-22 15:49 ` Tamas Blummer
2014-04-22 17:03 ` Mark Friedenbach
2014-04-22 17:07 ` Jan Møller
2014-04-22 18:29 ` Tamas Blummer
2014-04-22 18:46 ` Gregory Maxwell
2014-04-23 5:33 ` Tamas Blummer
2014-04-23 6:16 ` Gregory Maxwell
2014-05-05 19:36 ` Nikita Schmidt
2014-05-12 12:09 ` Jan Møller
2014-08-14 19:23 ` Nikita Schmidt
2014-04-22 13:37 ` Nikita Schmidt
2014-04-22 8:15 ` Gregory Maxwell
2014-04-22 8:49 ` Jan Møller
-- strict thread matches above, loose matches on Subject: below --
2014-03-29 8:05 Matt Whitlock
2014-03-29 8:34 ` Tamas Blummer
2014-03-29 8:44 ` Tamas Blummer
2014-03-29 8:51 ` Matt Whitlock
2014-03-29 8:54 ` Matt Whitlock
2014-03-29 16:54 ` Matt Whitlock
2014-03-29 17:37 ` Tamas Blummer
2014-03-29 9:08 ` Chris Beams
2014-03-29 9:31 ` Matt Whitlock
2014-03-29 11:16 ` Matt Whitlock
2014-03-29 11:54 ` Chris Beams
2014-03-29 13:27 ` Jeff Garzik
2014-03-29 13:36 ` Mike Hearn
2014-03-29 13:38 ` Tamas Blummer
2014-03-29 14:10 ` Matt Whitlock
2014-03-29 14:19 ` Jeff Garzik
2014-03-29 14:55 ` Matt Whitlock
2014-03-29 15:04 ` Mike Hearn
2014-03-29 14:28 ` Watson Ladd
2014-03-29 14:36 ` Gregory Maxwell
2014-03-29 15:01 ` Matt Whitlock
2014-03-29 9:21 ` Chris Beams
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