Subject: Re: [Bitcoin-development] Addressing rapid changes in mining power

From: Gavin Andresen <[email-masked]>
Date: Wed, 23 Nov 2011 10:09:10 -0500

On Wed, Nov 23, 2011 at 9:38 AM, Christian Decker
<[email-masked]> wrote:
> At some point you might find an incredibly hard block that makes your forked
> chain the hardest one in the network

Seems to me that's the real problem with any "hardest block found in X
minutes" scheme.

If I get lucky and find a really extremely hard block then I have an
incentive to keep it secret and build a couple more blocks on top of
it, then announce them all at the same time.

If the rest of the network rejects my longer chain because I didn't
announce the extremely hard block in a timely fashion... then how
could the network ever recover from a real network split?  A network
split/rejoin will look exactly the same.

Bitcoin as-is doesn't have the "I got lucky and found an extremely
hard block" problem because the difficulty TARGET is used to compute
chain difficulty, not the actual hashes found.

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PS: I proposed a different method for dealing with large hash power
drops for the testnet on the Forums yesterday, and am testing it
today.

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Gavin Andresen