Received-SPF: pass (sog-mx-1.v43.ch3.sourceforge.com: domain of zikula.org
	designates 209.85.212.179 as permitted sender)
	client-ip=209.85.212.179; envelope-from=drak@zikula.org;
	helo=mail-wi0-f179.google.com; 
MIME-Version: 1.0
In-Reply-To: <N1-9eAtMHauq2@Safe-mail.net>
References: <N1-9eAtMHauq2@Safe-mail.net>
From: Drak <drak@zikula.org>
Date: Tue, 5 Nov 2013 22:15:27 +0000
Message-ID: <CANAnSg2sUfRH0mYEir_XKUz-iOYRpdzNgM-AJ7t-H=SOa4wBig@mail.gmail.com>
To: bitcoin-development@lists.sourceforge.net
Content-Type: multipart/alternative; boundary=047d7b624e2adfc61004ea755fe5
Subject: Re: [Bitcoin-development] Possible Solution To SM Attack
Precedence: list

--047d7b624e2adfc61004ea755fe5
Content-Type: text/plain; charset=UTF-8

On 5 November 2013 20:51, <colj@safe-mail.net> wrote:

> Possible Solution:
> If N amount of blocks built of the same previous block are received within
> a time frame of T mine on the block with the lowest hash.
>
> Logic:
> In order for Alice to pull of this attack she not only has to propagate
> her blocks first she must also ensure her blocks are of the smallest hash.
>
> Alice would now have to decrease her target to pull of this attack. Since
> she has a lower target it will take her longer to find a valid block
> negating her time advantage.


If I understand the issue properly, this seems like a pretty elegant
solution: if two blocks are broadcast within a certain period of eachother,
chose the lower target. That's a provable fair way of randomly choosing the
winning block and would seem like a pretty simply patch.

Drak

--047d7b624e2adfc61004ea755fe5
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr">On 5 November 2013 20:51,=C2=A0<span dir=3D"ltr">&lt;<a hr=
ef=3D"mailto:colj@safe-mail.net" target=3D"_blank">colj@safe-mail.net</a>&g=
t;</span>=C2=A0wrote:<br><div class=3D"gmail_extra"><div class=3D"gmail_quo=
te"><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;bor=
der-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:sol=
id;padding-left:1ex">

Possible Solution:<br>If N amount of blocks built of the same previous bloc=
k are received within a time frame of T mine on the block with the lowest h=
ash.<br><br>Logic:<br>In order for Alice to pull of this attack she not onl=
y has to propagate her blocks first she must also ensure her blocks are of =
the smallest hash.<br>

<br>Alice would now have to decrease her target to pull of this attack. Sin=
ce she has a lower target it will take her longer to find a valid block neg=
ating her time advantage.</blockquote><div><br></div><div>If I understand t=
he issue properly, this seems like a pretty elegant solution: if two blocks=
 are broadcast within a certain period of eachother, chose the lower target=
. That&#39;s a provable fair way of randomly choosing the winning block and=
 would seem like a pretty simply patch.</div>

<div><br></div><div>Drak</div></div></div></div>

--047d7b624e2adfc61004ea755fe5--