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From: Erik Aronesty <erik@q32.com>
To: "Russell O'Connor" <roconnor@blockstream.io>
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Multiparty signatures
Date: Fri, 20 Jul 2018 12:25:34 -0400	[thread overview]
Message-ID: <CAJowKgJBVdJbRvf5Y6dV4o5Jf1XyELNsT+vCrp4b-86ZYr+LYQ@mail.gmail.com> (raw)
In-Reply-To: <CAMZUoK=iNgsZVb89gYRDUdZu0AkTGQ8cXqqbk3NXHEONBpO5ow@mail.gmail.com>

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That's a great point.  It's been solved in musig and that doesn't change
the m of n multisig construction.

You use the same musig construction where you hash all keys and sum the
multiples....and use that when computing k ... the shared blinding
factor.... you're still improving the system .... Getting a nice Shamir m
of n multisig.... with a single signature...and all the same properties
otherwise.


On Thu, Jul 19, 2018, 9:11 AM Russell O'Connor <roconnor@blockstream.io>
wrote:

> On Thu, Jul 19, 2018 at 8:16 AM, Erik Aronesty via bitcoin-dev <
> bitcoin-dev@lists.linuxfoundation.org> wrote:
>
>>  you can't birthday attack something where there's only a single variable
>> that you can modify.
>>
>
> When engaging in a multiparty signature, the attacker can more than one
> variable to modify.  When you are party to a multi-party signature (for
> example, in some sort of coin-join protocol) it could be that every other
> participant in the multi-party signature is, in fact, the same single
> attacker representing themselves as multiple participants.  This is how the
> attacker gets their hands on multiple variables.
>
>
>

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  reply	other threads:[~2018-07-20 16:25 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-08 14:19 [bitcoin-dev] Multiparty signatures Erik Aronesty
2018-07-08 15:16 ` Tim Ruffing
2018-07-08 18:23   ` Erik Aronesty
2018-07-08 21:01   ` Gregory Maxwell
2018-07-09  0:27     ` Erik Aronesty
2018-07-09  2:33       ` Pieter Wuille
2018-07-09  4:29         ` Erik Aronesty
2018-07-09  4:39           ` Pieter Wuille
     [not found]             ` <CAJowKg+=7nS4gNmtc8a4-2cu1uCOPqxjfchFwDVqUciKNMUYWQ@mail.gmail.com>
2018-07-09 15:02               ` Erik Aronesty
2018-07-09 15:57                 ` Dan Robinson
2018-07-09 15:59                 ` Gregory Maxwell
2018-07-09 16:33                   ` Erik Aronesty
2018-07-09 16:58                     ` Gregory Maxwell
2018-07-09 17:59                       ` Erik Aronesty
2018-07-10 11:46                         ` Erik Aronesty
2018-07-11 10:35                           ` Adam Back
2018-07-11 14:45                             ` Erik Aronesty
2018-07-19 12:16                               ` Erik Aronesty
2018-07-19 12:24                                 ` Erik Aronesty
2018-07-19 13:11                                 ` Russell O'Connor
2018-07-20 16:25                                   ` Erik Aronesty [this message]
2018-07-20 17:34                                     ` Erik Aronesty
2018-07-20 20:18                                       ` Erik Aronesty
2018-07-26  2:05                                         ` Erik Aronesty
2018-07-09 16:21                 ` Gregory Maxwell
2018-07-09  2:29 ` Pieter Wuille

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