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From: Alan Reiner <etotheipi@gmail.com>
To: Matt Whitlock <bip@mattwhitlock.name>
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 13:52:20 -0400	[thread overview]
Message-ID: <53370854.5050303@gmail.com> (raw)
In-Reply-To: <15872432.k8h0hUxqlf@crushinator>

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.





  reply	other threads:[~2014-03-29 17:52 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 ` [Bitcoin-development] Presenting a BIP for Shamir's Secret Sharing of Bitcoin private keys Matt Whitlock
2014-03-29 16:59   ` Alan Reiner
2014-03-29 17:19     ` Matt Whitlock
2014-03-29 17:52       ` Alan Reiner [this message]
2014-03-29 18:00         ` Matt Whitlock
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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