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From: Tier Nolan <tier.nolan@gmail•com>
To: Braydon Fuller via bitcoin-dev <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Chain width expansion
Date: Tue, 15 Oct 2019 19:30:58 +0100	[thread overview]
Message-ID: <CAE-z3OWRv1aw4_meRRon+5OA1rxerTr9=0DLWC5d7Xhyg8veBQ@mail.gmail.com> (raw)
In-Reply-To: <93649df9-27ab-abaf-00f3-da6c528344cc@purse.io>

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On Tue, Oct 15, 2019 at 7:29 AM Braydon Fuller via bitcoin-dev <
bitcoin-dev@lists•linuxfoundation.org> wrote:

> So I don't think you can use the height in the coinbase for that
> purpose, as it's not possible to validate it without the previous
> headers. That's common for more than just the height.
>

It is a property of blockchains that the lowest digest for a chain
represents the total chainwork.

Estimate total hash count = N * (2^256) / (Nth lowest (i.e. strongest)
digest over all headers)

To produce a fake set of 10 headers that give a higher work estimate than
the main chain would require around the same effort as went into the main
chain in the first place.  You might as well completely build an
alternative chain.

Working backwards for one of those headers, you have to follow the actual
chain back to genesis.

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  parent reply	other threads:[~2019-10-15 18:31 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-04  0:38 Braydon Fuller
2019-10-04  8:20 ` David A. Harding
2019-10-04 19:51   ` Braydon Fuller
2019-10-11 21:24   ` Braydon Fuller
2019-10-04 23:31 ` Tier Nolan
2019-10-10 16:16   ` Braydon Fuller
2019-10-12 16:27     ` Tier Nolan
2019-10-12 17:56       ` Joachim Strömbergson
2019-10-12 20:46         ` Tier Nolan
2019-10-16 19:07           ` Braydon Fuller
2019-10-15  0:42         ` Braydon Fuller
2019-10-15  7:20           ` Joachim Strömbergson
2019-10-15  8:12             ` Braydon Fuller
2019-10-15 15:50               ` Joachim Strömbergson
2019-10-16 19:25                 ` Braydon Fuller
2019-10-15 18:30           ` Tier Nolan [this message]
2019-10-15  0:38       ` Braydon Fuller

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