Received-SPF: pass (sog-mx-1.v43.ch3.sourceforge.com: domain of gmail.com
	designates 209.85.219.45 as permitted sender)
	client-ip=209.85.219.45; envelope-from=mh.in.england@gmail.com;
	helo=mail-oa0-f45.google.com; 
MIME-Version: 1.0
Sender: mh.in.england@gmail.com
In-Reply-To: <CAAS2fgQP6mFb0izQxZcBwqBWdxKUiAy1sG23ScAZ+tEMvGU0WQ@mail.gmail.com>
References: <20130514115151.GA21600@netbook.cypherspace.org>
	<20130514140902.GA22447@netbook.cypherspace.org>
	<20130515102509.GA3401@netbook.cypherspace.org>
	<20130515111906.GA26020@savin>
	<20130515114956.GA5863@netbook.cypherspace.org>
	<5193825B.20909@lavabit.com>
	<20130515162129.GB6156@netbook.cypherspace.org>
	<20130515234030.GA17920@netbook.cypherspace.org>
	<BF1C6C71-9EE5-4A2F-8B73-3E8F934A7CAE@gmail.com>
	<CAAS2fgQP6mFb0izQxZcBwqBWdxKUiAy1sG23ScAZ+tEMvGU0WQ@mail.gmail.com>
Date: Wed, 15 May 2013 19:22:51 -0700
Message-ID: <CANEZrP2dFi-3nZhYpaA9RfJ8N2e-GQ_YQtKMdnFfPx-9YLU6MA@mail.gmail.com>
From: Mike Hearn <mike@plan99.net>
To: Gregory Maxwell <gmaxwell@gmail.com>
Content-Type: multipart/alternative; boundary=089e01634f0e1121a404dccc8b45
Cc: "bitcoin-development@lists.sourceforge.net"
	<bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] blind symmetric commitment for stronger
 byzantine voting resilience (Re: bitcoin taint & unilateral revocability)
Precedence: list

--089e01634f0e1121a404dccc8b45
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

Conceptually it sounds a lot like ZeroCoin (not in implementation)?

I'm not really convinced miner cartels that try to exclude transactions are
likely to be a big deal, but such schemes could I suppose be kept in a back
pocket in case one day I'm proven wrong.


On Wed, May 15, 2013 at 6:39 PM, Gregory Maxwell <gmaxwell@gmail.com> wrote=
:

> On Wed, May 15, 2013 at 6:24 PM, Gavin <gavinandresen@gmail.com> wrote:
> > Busy with pre-conference stuff, not following details of this
> conversation...
> >
> > ... but it sounds a lot like the "guy fawkes" protocol Zooko was
> thinking about a year or so ago.
>
> Sort of, but in a guy fawkes signature you use the commitment to hide
> the preimage that proves you had authority to spend a coin.   Adam
> proposes you do this in order to hide _which coin you're spending_.
>
> This has obvious anti-DOS complications, but Adam deftly dodged my
> initial attempts to shoot him down on these grounds by pointing out
> that you could mix blinded and blinded inputs and have priority and
> transaction fees come from only the unblinded ones.
>
> Effectively,  it means that so long as you could convince the network
> to let you spend some coins, you could also spend other ones along for
> the ride and the network wouldn't know which ones those were until it
> was too late for it to pretend it never saw them.
>
> I think there are all kinds of weird economic implications to this=E2=80=
=94 a
> blinded payment would seem to have a different utility level to an
> unblinded one: you can't use it for fees=E2=80=94 except you can unblind =
it at
> any time.  And the discontinuousness  ("two types of inputs") and that
> it would enable mining gibberish (though perhaps not data storage, if
> you see my preimage solution to that) seems awkward and I think I have
> to spend some time internalizing it before I can really think through
> the implications.
>
>
> -------------------------------------------------------------------------=
-----
> 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
> _______________________________________________
> Bitcoin-development mailing list
> Bitcoin-development@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
>

--089e01634f0e1121a404dccc8b45
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr">Conceptually it sounds a lot like ZeroCoin (not in impleme=
ntation)?<div><br></div><div>I&#39;m not really convinced miner cartels tha=
t try to exclude transactions are likely to be a big deal, but such schemes=
 could I suppose be kept in a back pocket in case one day I&#39;m proven wr=
ong.</div>
</div><div class=3D"gmail_extra"><br><br><div class=3D"gmail_quote">On Wed,=
 May 15, 2013 at 6:39 PM, Gregory Maxwell <span dir=3D"ltr">&lt;<a href=3D"=
mailto:gmaxwell@gmail.com" target=3D"_blank">gmaxwell@gmail.com</a>&gt;</sp=
an> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex"><div class=3D"im">On Wed, May 15, 2013 at 6:=
24 PM, Gavin &lt;<a href=3D"mailto:gavinandresen@gmail.com">gavinandresen@g=
mail.com</a>&gt; wrote:<br>

&gt; Busy with pre-conference stuff, not following details of this conversa=
tion...<br>
&gt;<br>
&gt; ... but it sounds a lot like the &quot;guy fawkes&quot; protocol Zooko=
 was thinking about a year or so ago.<br>
<br>
</div>Sort of, but in a guy fawkes signature you use the commitment to hide=
<br>
the preimage that proves you had authority to spend a coin. =C2=A0 Adam<br>
proposes you do this in order to hide _which coin you&#39;re spending_.<br>
<br>
This has obvious anti-DOS complications, but Adam deftly dodged my<br>
initial attempts to shoot him down on these grounds by pointing out<br>
that you could mix blinded and blinded inputs and have priority and<br>
transaction fees come from only the unblinded ones.<br>
<br>
Effectively, =C2=A0it means that so long as you could convince the network<=
br>
to let you spend some coins, you could also spend other ones along for<br>
the ride and the network wouldn&#39;t know which ones those were until it<b=
r>
was too late for it to pretend it never saw them.<br>
<br>
I think there are all kinds of weird economic implications to this=E2=80=94=
 a<br>
blinded payment would seem to have a different utility level to an<br>
unblinded one: you can&#39;t use it for fees=E2=80=94 except you can unblin=
d it at<br>
any time. =C2=A0And the discontinuousness =C2=A0(&quot;two types of inputs&=
quot;) and that<br>
it would enable mining gibberish (though perhaps not data storage, if<br>
you see my preimage solution to that) seems awkward and I think I have<br>
to spend some time internalizing it before I can really think through<br>
the implications.<br>
<div class=3D"HOEnZb"><div class=3D"h5"><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>
</div></div></blockquote></div><br></div>

--089e01634f0e1121a404dccc8b45--