Subject: Re: [bitcoin-dev] assumeutxo and UTXO snapshots

From: Peter Todd <[email-masked]>
Date: Sat, 13 Apr 2019 15:09:25 -0400

On Wed, Apr 03, 2019 at 02:39:32PM -0700, Dave Scotese via bitcoin-dev wrote:
> Every block's hash is smaller than the difficulty at that time.  Block
> 569927's hash was VERY small (started with 21 zeros).  The ratio of block
> hash to difficulty requirement (0xffffffff - difficulty, I think) could be
> used to identify blocks as "special," thus providing the opportunity to
> popularize unimportant but memorable-and-therefore-useful details.  How can
> they be useful if they are unimportant?  They are useful for sanity
> checking.  For example, if the drunken bishop walk (or some other popular
> randomart) produced by block 569927's hash looked like a face, that would
> be memorable: "The block with the smallest hash in 2019 (maybe ever?) looks
> like a face after the drunken bishop walk."

As hashest smaller than the target have no significance to the Bitcoin
consensus I'd suggest not basing any features on that property. It's just as
arbitrary as picking whole decimal number block heights, yet has the additional
downsides of being harder to compute, and being likely to confuse people as to
how the Bitcoin consensus works.

-- 
https://petertodd.org 'peter'[:-1]@petertodd.org