Received-SPF: pass (sog-mx-4.v43.ch3.sourceforge.com: domain of lavabit.com
	designates 72.249.41.33 as permitted sender)
	client-ip=72.249.41.33; envelope-from=calebdelisle@lavabit.com;
	helo=karen.lavabit.com; 
Message-ID: <5193825B.20909@lavabit.com>
Date: Wed, 15 May 2013 08:40:59 -0400
From: Caleb James DeLisle <calebdelisle@lavabit.com>
User-Agent: Mozilla/5.0 (X11; Linux x86_64;
	rv:17.0) Gecko/20130404 Thunderbird/17.0.5
MIME-Version: 1.0
To: bitcoin-development@lists.sourceforge.net
References: <20130514115151.GA21600@netbook.cypherspace.org>
	<20130514140902.GA22447@netbook.cypherspace.org>
	<20130515102509.GA3401@netbook.cypherspace.org>
	<20130515111906.GA26020@savin>
	<20130515114956.GA5863@netbook.cypherspace.org>
In-Reply-To: <20130515114956.GA5863@netbook.cypherspace.org>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Subject: Re: [Bitcoin-development] blind symmetric commitment for stronger
 byzantine voting resilience (Re: bitcoin taint & unilateral revocability)
Precedence: list

I can't see this working, if 51% of the mining power doesn't like your
coins, when you create the commitment they will reject it.
If the commitment is opaque at the time of inclusion in the block then
I will create multiple commitments and then after revealing the
commitment and spend to you I will reveal the earlier commitment which
commits the coins to an address I control.

On the topic of reversibility, I suspect in the long term the lack of
chargebacks will create issues as criminals learn that for the first
time in history, kidnap & ransom is effective. Suffice to say after the
first >= $10mn kidnapping-for-bitcoin heist, governments will be forced
to decide how they view the system. It will likely fall somewhere between
"arrest/question anyone identified holding tainted coins" to something
nonsensical and reactionary like "blocking" bitcoin as Iran does TOR.

Thanks,
Caleb


On 05/15/2013 07:49 AM, Adam Back wrote:
> On Wed, May 15, 2013 at 07:19:06AM -0400, Peter Todd wrote:
>> Protocols aren't set in stone - any attacker that controls enough
>> hashing power to pose a 51% attack can simply demand that you use a
>> Bitcoin client modified [to facilitate evaluation of his policy]
> 
> Protocol voting is a vote per user policy preference, not a CPU vote, which
> is the point.  Current bitcoin protocol is vulnerable to hard to prove
> arbitrary policies being imposable by a quorum of > 50% miners.  The blind
> commitment proposal fixes that, so even an 99% quorum cant easily impose
> policies, which leaves the weaker protocol vote attack as the remaining
> avenue of attack.  That is a significant qualitative improvement.
> 
> The feasibility of protocol voting attacks is an open question, but you
> might want to consider the seeming unstoppability of p2p protocols for a
> hint.
> 
> Adam
> 
> ------------------------------------------------------------------------------
> 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
>