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Date: Wed, 12 Mar 2014 12:24:58 -0400
From: Peter Todd <pete@petertodd.org>
To: Mike Hearn <mike@plan99.net>
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Cc: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] Multisign payment protocol?
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On Wed, Mar 12, 2014 at 05:14:25PM +0100, Mike Hearn wrote:
> >
> > Can this be calculated in advance knowing the initial transaction size =
and
> > the number of signatures required?
> >
>=20
> Sure of course. You assume each signature to be placed in the tx is 73
> bytes. Not very hard, but if the tx you get back from the API doesn't
> contain such a 73-byte sentinel value then it's harder to be sure that th=
is
> part was done correctly.

Multisig signing is an example of untrusted input from an adversary;
this is a good example where you'd be better off just handling it
correctly rather than trying to "make it easier". (although handling it
correctly may include internally converting every not-yet-signed dummy
signature into a 73 bytes pushdata prior to calculating the size)

--=20
'peter'[:-1]@petertodd.org
0000000000000000e18643801741dc70db6fda175230012b0f697024218cd9ef

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