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From: Tom Harding <tomh@thinlink.com>
To: Bitcoin-Dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Interpreting nTime for the purpose of Bitcoin-attested timestamps
Date: Mon, 19 Sep 2016 09:13:40 -0700	[thread overview]
Message-ID: <7ff1a87d-2916-2024-ea05-d6413bd17767@thinlink.com> (raw)
In-Reply-To: <20160918042001.GA9076@fedora-21-dvm>


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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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  parent reply	other threads:[~2016-09-19 16:13 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-18  4:20 [bitcoin-dev] Interpreting nTime for the purpose of Bitcoin-attested timestamps Peter Todd
     [not found] ` <CABeL=0jSQsdyRFAUheQ9XSi1krM=PLFAARLXE8Du55FFkX8vZg@mail.gmail.com>
2016-09-18 16:05   ` Peter Todd
2016-09-19 16:13 ` Tom Harding [this message]
2016-09-19 17:56   ` Peter Todd
2016-09-19 19:53     ` Tom Harding

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