Subject: Re: [bitcoin-dev] [BIP Proposal] Buried Deployments

From: Pieter Wuille <[email-masked]>
Date: Wed, 16 Nov 2016 17:50:53 -0800

On Wed, Nov 16, 2016 at 5:58 AM, Eric Voskuil via bitcoin-dev <
[email-masked]> wrote:

> This sort of statement represents one consequence of the aforementioned
> bad precedent.
>
> Are checkpoints good now?
>

So far in this discussion, and in a thread that has forked off, I think 3
cases of implementation aspects have been mentioned that under certain
circumstances result in the validity of chains changing:
* Buried softforks (by simplifying the activation rules for certain rules)
* Not verifying BIP30 after BIP34 is active (since only under a SHA256^2
collision a duplicate txid can occur)
* The existence (and/or removal) of checkpoints (in one form or another).

None of these will influence the accepted main chain, however. If they ever
do, Bitcoin has far worse things to worry about (years-deep reorgs, or
SHA256 collisions).

If you were trying to point out that buried softforks are similar to
checkpoints in this regard, I agree. So are checkpoints good now? I believe
we should get rid of checkpoints because they seem to be misunderstood as a
security feature rather than as an optimization. I don't think buried
softforks have that problem.

-- 
Pieter