Subject: Re: [bitcoin-dev] A Better MMR Definition

From: Bram Cohen <[email-masked]>
Date: Thu, 23 Feb 2017 19:32:43 -0800

On Thu, Feb 23, 2017 at 7:15 PM, Peter Todd <[email-masked]> wrote:

>
> Glad we're on the same page with regard to what's possible in TXO
> commitments.
>
> Secondly, am I correct in saying your UTXO commitments scheme requires
> random
> access? While you describe it as a "merkle set", obviously to be merkelized
> it'll have to have an ordering of some kind. What do you propose that
> ordering
> to be?
>

The ordering is by the bits in the hash. Technically it's a Patricia Trie.
I'm using 'merkle tree' to refer to basically anything with a hash root.

> Maybe more specifically, what exact values do you propose to be in the set?
>
>
That is unspecified in the implementation, it just takes a 256 bit value
which is presumably a hash of something. The intention is to nail down a
simple format and demonstrate good performance and leave those semantics to
a higher layer. The simplest thing would be to hash together the txid and
output number.