References: <20160918042001.GA9076@fedora-21-dvm>
From: Tom Harding <tomh@thinlink.com>
To: Bitcoin-Dev <bitcoin-dev@lists.linuxfoundation.org>
Message-ID: <7ff1a87d-2916-2024-ea05-d6413bd17767@thinlink.com>
Date: Mon, 19 Sep 2016 09:13:40 -0700
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Subject: Re: [bitcoin-dev] Interpreting nTime for the purpose of
 Bitcoin-attested timestamps
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On 9/17/2016 9:20 PM, Peter Todd via bitcoin-dev wrote:
> The probability that all N blocks are found by dishonest miners is q^N,

That's the probability that dishonest miners find N blocks in a row
immediately.  What you want is the probability that they can build a
chain N blocks long, taking the random-walk into account.

So use Satoshi's formula from bitcoin.pdf, section 11.  The results are
remarkably different.  In particular, q=.5 is totally insecure, since
for any N, both factions are guaranteed to eventually possess a chain of
length N anchored at x at some point during the wild reorg melee.

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