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Date: Mon, 12 May 2014 06:04:47 -0700
From: Tom Harding <tomh@thinlink.com>
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Subject: Re: [Bitcoin-development] A statistical consensus rule for reducing
0-conf double-spend risk
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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
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