public inbox for bitcoindev@googlegroups.com
 help / color / mirror / Atom feed
From: Tamas Blummer <tamas@bitsofproof.com>
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 19:16:28 +0100	[thread overview]
Message-ID: <19FE9882-7FC2-4518-BD50-8818B059271B@bitsofproof.com> (raw)
In-Reply-To: <53370854.5050303@gmail.com>


[-- Attachment #1.1: Type: text/plain, Size: 2296 bytes --]

I also think that we can add usability features if the underlying secret remains well protected.
I do not think there is any reason to assume that the knowledge of the degree of the polynomial, would aid an attacker.

Similarly a fingerprint of the secret if it is unrelated to the hash used in the polinomyal should leak no useful information,

The length of such fingerpring (say 4 bytes) and the degree (1 byte) does not seem a big overhead for me.

Remember that the biggest obstacle of Bitcoin is usability not security.

Regards,

Tamas Blummer
http://bitsofproof.com

On 29.03.2014, at 18:52, Alan Reiner <etotheipi@gmail.com> 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.
> 
> 
> 
> ------------------------------------------------------------------------------
> _______________________________________________
> Bitcoin-development mailing list
> Bitcoin-development@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
> 


[-- Attachment #1.2: Type: text/html, Size: 5709 bytes --]

[-- Attachment #2: Message signed with OpenPGP using GPGMail --]
[-- Type: application/pgp-signature, Size: 495 bytes --]

  parent reply	other threads:[~2014-03-29 18:16 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
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 [this message]
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=19FE9882-7FC2-4518-BD50-8818B059271B@bitsofproof.com \
    --to=tamas@bitsofproof.com \
    --cc=bitcoin-development@lists.sourceforge.net \
    --cc=etotheipi@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox