From: Peter Todd <pete@petertodd•org>
To: Eric Lombrozo <elombrozo@gmail•com>
Cc: Bitcoin Dev <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] On the security of softforks
Date: Fri, 18 Dec 2015 04:18:45 -0800 [thread overview]
Message-ID: <20151218121845.GB22789@muck> (raw)
In-Reply-To: <em9d607452-50c0-4aa2-941e-7b637a287a70@platinum>
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On Fri, Dec 18, 2015 at 03:02:36AM +0000, Eric Lombrozo via bitcoin-dev wrote:
> First of all, that's an expensive beer!
>
> Second of all, any consensus rule change risks non-full-validating
> or non-upgraded nodes seeing invalid confirmations...but assuming a
> large supermajority (i.e. > 95%) of hashing power is behind the new
> rule, it is extremely unlikely that very many invalid confirmations
> will ever be seen by anyone. The number of confirmations you require
To clarify, because the 95% of upgraded hashing power is creating valid
blocks from the point of view of the remaining 5%, that 95% majority
will continually reorg the 5% non-upgrading chain. This ensures that the
invalid chain remains short, and thus the # of invalid confirmations
possible remains small. For instance, the chance of getting one invalid
confirmation is 0.05^1 = 5%, two invalid confirmations 0.05^2 = 0.25%, three
0.05^3 = 0.01% etc.
Whereas with a hard fork, the 5% of miners will continue mining on their
own chain. While that chain's length will increase more slowly than
normal, the # of confirmations that non-upgraded clients will see on it
are unbounded.
Anyway, we should write this up as a BIP - there's been a tremendous
amount of misinformation, even flat out lies, floating around on this
subject.
--
'peter'[:-1]@petertodd.org
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next prev parent reply other threads:[~2015-12-18 12:18 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-18 2:30 Pieter Wuille
2015-12-18 2:47 ` Jonathan Toomim
2015-12-18 3:02 ` Eric Lombrozo
2015-12-18 12:18 ` Peter Todd [this message]
2015-12-19 15:48 ` Bryan Bishop
2015-12-18 3:10 ` jl2012
2015-12-18 5:32 ` Jorge Timón
2015-12-18 6:12 ` Anthony Towns
2015-12-19 1:36 ` Chris
2015-12-19 17:46 ` Andrew
2015-12-20 4:14 ` Rusty Russell
2015-12-20 19:16 ` jl2012
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