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From: Tom Harding <tomh@thinlink.com>
To: bitcoin-development@lists.sourceforge.net
Subject: Re: [Bitcoin-development] A statistical consensus rule for reducing 0-conf double-spend risk
Date: Mon, 12 May 2014 06:04:47 -0700	[thread overview]
Message-ID: <5370C6EF.8020001@thinlink.com> (raw)
In-Reply-To: <537050E0.2040008@thinlink.com>

Sorry to run on, a correction is needed.  A much better approximation 
requires that the rule-following minority finds the next TWO blocks, so 
the cost is

(total miner revenue of block)*(fraction of hashpower following the rule)^2

So the lower bound cost in this very pessimistic scenario is .0025 BTC,  
still quite high for one transaction.  I guess miner could try to make a 
business out of mining double-spends, to defray that cost.


On 5/11/2014 9:41 PM, Tom Harding wrote:
> Back up to the miner who decided to include a "seasoned" double-spend 
> in his block.  Let's say he saw it 21 seconds after he saw an earlier 
> spend, and included it, despite the rule.
>
> The expected cost of including the respend is any revenue loss from 
> doing so: (total miner revenue of block)*(fraction of hashpower 
> following the rule).  So today, if only 1% of hashpower follows the 
> rule (ie a near total failure of consensus implementation), he still 
> loses at least .25 BTC.
>
> .25 BTC is about 1000x the typical "double-spend premium" I'm seeing 
> right now.  Wouldn't the greedy-rational miner just decide to include 
> the earlier spend instead 





      reply	other threads:[~2014-05-12 13:04 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-04  0:29 [Bitcoin-development] A statistical consensus rule for reducing 0-conf double-spend risk Tom Harding
2014-05-04  2:54 ` Christophe Biocca
2014-05-06 17:49   ` Tom Harding
2014-05-12  4:41   ` Tom Harding
2014-05-12 13:04     ` Tom Harding [this message]

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