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From: "Ondřej Vejpustek" <ondrej.vejpustek@satoshilabs.com>
To: Gregory Maxwell <greg@xiph.org>
Cc: Bitcoin Dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Satoshilabs secret shared private key scheme
Date: Thu, 18 Jan 2018 17:59:09 +0100	[thread overview]
Message-ID: <d6eb0fc3-d729-30cb-986b-b1d7b8aacbd6@satoshilabs.com> (raw)
In-Reply-To: <CAAS2fgSw0mAQPJ-ai-3kFr7pWXd7pjbrEoXN4r6Ak3o4c8_vjw@mail.gmail.com>

> If being secure against partial share leakage is really part of your
> threat model the current proposal is gratuitously insecure against it.

I don't think that is true. Shared secret is an input of KDF which
should prevent this kind of attack.

> If partial share disclosure were an actual concern, I would recommend
> that after sharing and before encoding for transmission (e.g. before
> applying check values and word encoding to the share) the individual
> shares be passed through a large block unkeyed cryptographic
> permutation.  Under reasonable-ish assumptions about the difficulty of
> inverting the permutation with partial knowledge, this transformation
> would prevent attacks from leaks of partial share information.

Actually, we've been considering something like that. We concluded that
it is to much "rolling your own crypto". Instead of diffusion layer we
decided to apply KDF on the shared secret.


  reply	other threads:[~2018-01-18 17:00 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-17 11:39 [bitcoin-dev] Satoshilabs secret shared private key scheme Ondřej Vejpustek
2018-01-17 15:28 ` Russell O'Connor
2018-01-17 15:36   ` Gregory Maxwell
2018-01-17 15:31 ` Gregory Maxwell
2018-01-18  5:00   ` Matt Corallo
2018-01-18 13:50   ` Ondřej Vejpustek
2018-01-18 14:34     ` Gregory Maxwell
2018-01-18 16:59       ` Ondřej Vejpustek [this message]
2018-01-18 18:58         ` Gregory Maxwell
2018-01-22 15:00           ` Ondřej Vejpustek
2018-01-22 19:21           ` Russell O'Connor
2018-01-23  1:05             ` Gregory Maxwell
2018-01-23 13:54           ` Ondřej Vejpustek
2018-01-23 14:16             ` Adam Back
  -- strict thread matches above, loose matches on Subject: below --
2018-01-08  4:22 Gregory Maxwell
2018-01-08  6:33 ` nullius
2018-01-08 12:39 ` Pavol Rusnak
2018-01-08 12:45   ` Peter Todd
2018-01-08 13:00     ` Pavol Rusnak
2018-01-08 19:37       ` Peter Todd
2018-01-08 22:26         ` Ben Kloester
2018-01-09  0:37           ` Peter Todd
2018-01-08 23:47   ` Gregory Maxwell
2018-01-09  0:40     ` Rhavar
2018-01-09  1:13       ` Peter Todd
2018-01-09 12:44         ` jens
     [not found]         ` <274aad5c-4573-2fdd-f8b0-c6c2d662ab7c@gibsonic.org>
2018-01-12  9:50           ` Peter Todd
2018-01-09 15:12     ` Pavol Rusnak
2018-01-10 20:28       ` Pavol Rusnak
2018-01-10 23:47         ` Gregory Maxwell
2018-01-11  9:55           ` Pavol Rusnak
2018-01-09 16:20   ` Russell O'Connor

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