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

From: Luke Dashjr <[email-masked]>
Date: Thu, 17 Nov 2016 03:06:01 +0000

On Wednesday, November 16, 2016 9:01:00 PM Peter Todd via bitcoin-dev wrote:
> So, conceptually, another way to deal with this is to hardcode a blockhash
> where we allow blocks in a chain ending with that blockhash to _not_ follow
> BIP65, up until that blockhash, and any blockchain without that blockhash
> must respect BIP65 for all blocks in the chain.
> 
> This is a softfork: we've only added rules that made otherwise valid chains
> invalid, and at the same time we are still accepting large reorgs (albeit
> under stricter rules than before).
> 
> I'd suggest we call this a exemption hash - we've exempted a particular
> blockchains from a soft-forked rule that we would otherwise enforce.

While this is technically a softfork, I think it may behave somewhat like a 
hardfork if we're not careful. Particularly, is the chain up to the block 
immediately before the checkpoint itself valid on its own, or does it simply 
become retroactively valid when it hits that checkpoint?

P.S. Your PGP signature is invalid?