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In-Reply-To: <20130515113827.GB26020@savin>
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Date: Wed, 15 May 2013 14:41:09 +0200
Message-ID: <CAKaEYh+7uXvipQL6Qn1_t44H97Y18ywvk6brr_Wv3u-C5qef-A@mail.gmail.com>
From: Melvin Carvalho <melvincarvalho@gmail.com>
To: Peter Todd <pete@petertodd.org>
Content-Type: multipart/alternative; boundary=047d7b3a84367436bd04dcc110aa
Cc: Bitcoin-Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] 2BTC reward for making probabalistic
 double-spending via conflicting transactions easy
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On 15 May 2013 13:38, Peter Todd <pete@petertodd.org> wrote:

> Now that I have the replace-by-fee reward, I might as well spread the
> wealth a bit.
>
>
> So for all this discussion about replace-by-fee and the supposed
> security of zero-conf transactions, no-one seems to think much about how
> in practice very few vendors have a setup to detect if conflicting
> transactions were broadcast on the network simultaneously - after all if
> that is the case which transaction gets mined is up to chance, so much
> of the time you'll get away with a double spend. We don't yet have a
> mechanism to propagate double-spend warnings, and funny enough, in the
> case of a single txin transaction the double-spend warning is also
> enough information to allow miners to implement replace-by-fee.
>
>
> So I'm offering 2BTC for anyone who comes up with a nice and easy to use
> command line tool that lets you automagically create one version of the
> transaction sending the coins to the desired recipient, and another
> version sending all the coins back to you, both with the same
> transaction inputs. In addition to creating the two versions, you need
> to find a way to broadcast them both simultaneously to different nodes
> on the network. One clever approach might be to use blockchain.info's
> raw transaction POST API, and your local Bitcoin node.
>
> If you happen to be at the conference, a cool demo would be to
> demonstrate the attack against my Android wallet. I'll buy Bitcoins off
> of you at Mt. Gox rates + %10, and you can see if you can rip me off.
> Yes, you can keep the loot. :) This should be videotaped so we can put
> an educational video on youtube after.
>

Isnt it potentially inviting trouble by encouraging people to insert double
spends into the block chain?

Sure, zero conf isnt 100% safe, we all know that.

But neither is the postal service.  Doesnt mean we should be going around
promoting the creation of tools to go into people's maiilboxes and open
their letters!


>
> --
> 'peter'[:-1]@petertodd.org
> 00000000000000bafd0a55f013e058cc2a672ee0c66b9265a02390d80e4748f5
>
>
> ------------------------------------------------------------------------------
> AlienVault Unified Security Management (USM) platform delivers complete
> security visibility with the essential security capabilities. Easily and
> efficiently configure, manage, and operate all of your security controls
> from a single console and one unified framework. Download a free trial.
> http://p.sf.net/sfu/alienvault_d2d
> _______________________________________________
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> Bitcoin-development@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
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>

--047d7b3a84367436bd04dcc110aa
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr"><br><div class=3D"gmail_extra"><br><br><div class=3D"gmail=
_quote">On 15 May 2013 13:38, Peter Todd <span dir=3D"ltr">&lt;<a href=3D"m=
ailto:pete@petertodd.org" target=3D"_blank">pete@petertodd.org</a>&gt;</spa=
n> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex">Now that I have the replace-by-fee reward, I=
 might as well spread the<br>
wealth a bit.<br>
<br>
<br>
So for all this discussion about replace-by-fee and the supposed<br>
security of zero-conf transactions, no-one seems to think much about how<br=
>
in practice very few vendors have a setup to detect if conflicting<br>
transactions were broadcast on the network simultaneously - after all if<br=
>
that is the case which transaction gets mined is up to chance, so much<br>
of the time you&#39;ll get away with a double spend. We don&#39;t yet have =
a<br>
mechanism to propagate double-spend warnings, and funny enough, in the<br>
case of a single txin transaction the double-spend warning is also<br>
enough information to allow miners to implement replace-by-fee.<br>
<br>
<br>
So I&#39;m offering 2BTC for anyone who comes up with a nice and easy to us=
e<br>
command line tool that lets you automagically create one version of the<br>
transaction sending the coins to the desired recipient, and another<br>
version sending all the coins back to you, both with the same<br>
transaction inputs. In addition to creating the two versions, you need<br>
to find a way to broadcast them both simultaneously to different nodes<br>
on the network. One clever approach might be to use <a href=3D"http://block=
chain.info" target=3D"_blank">blockchain.info</a>&#39;s<br>
raw transaction POST API, and your local Bitcoin node.<br>
<br>
If you happen to be at the conference, a cool demo would be to<br>
demonstrate the attack against my Android wallet. I&#39;ll buy Bitcoins off=
<br>
of you at Mt. Gox rates + %10, and you can see if you can rip me off.<br>
Yes, you can keep the loot. :) This should be videotaped so we can put<br>
an educational video on youtube after.<br></blockquote><div><br></div><div>=
Isnt it potentially inviting trouble by encouraging people to insert double=
 spends into the block chain?<br><br></div><div>Sure, zero conf isnt 100% s=
afe, we all know that.<br>
<br>But neither is the postal service.=A0 Doesnt mean we should be going ar=
ound promoting the creation of tools to go into people&#39;s maiilboxes and=
 open their letters!</div><div>=A0</div><blockquote class=3D"gmail_quote" s=
tyle=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">

<span class=3D"HOEnZb"><font color=3D"#888888"><br>
--<br>
&#39;peter&#39;[:-1]@<a href=3D"http://petertodd.org" target=3D"_blank">pet=
ertodd.org</a><br>
00000000000000bafd0a55f013e058cc2a672ee0c66b9265a02390d80e4748f5<br>
</font></span><br>---------------------------------------------------------=
---------------------<br>
AlienVault Unified Security Management (USM) platform delivers complete<br>
security visibility with the essential security capabilities. Easily and<br=
>
efficiently configure, manage, and operate all of your security controls<br=
>
from a single console and one unified framework. Download a free trial.<br>
<a href=3D"http://p.sf.net/sfu/alienvault_d2d" target=3D"_blank">http://p.s=
f.net/sfu/alienvault_d2d</a><br>___________________________________________=
____<br>
Bitcoin-development mailing list<br>
<a href=3D"mailto:Bitcoin-development@lists.sourceforge.net">Bitcoin-develo=
pment@lists.sourceforge.net</a><br>
<a href=3D"https://lists.sourceforge.net/lists/listinfo/bitcoin-development=
" target=3D"_blank">https://lists.sourceforge.net/lists/listinfo/bitcoin-de=
velopment</a><br>
<br></blockquote></div><br></div></div>

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