From: Peter Todd <pete@petertodd•org>
To: Bram Cohen <bram@bittorrent•com>
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] A Better MMR Definition
Date: Thu, 23 Feb 2017 21:58:11 -0500 [thread overview]
Message-ID: <20170224025811.GA31911@savin.petertodd.org> (raw)
In-Reply-To: <CA+KqGkrOK76S3ffPJmpqYcBwtSeKESqN16yZsrwzDR6JZZmwFA@mail.gmail.com>
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On Thu, Feb 23, 2017 at 06:50:10PM -0800, Bram Cohen wrote:
> On Thu, Feb 23, 2017 at 5:09 PM, Peter Todd <pete@petertodd•org> wrote:
>
> > I think you've misunderstood what TXO commitments are. From my article:
> >
> > "A merkle tree committing to the state of all transaction outputs, both
> > spent
> > and unspent, can provide a method of compactly proving the current state
> > of an
> > output."
> > -https://petertodd.org/2016/delayed-txo-commitments#txo-commitments:
> >
>
> The proposal on that page is of a tree which does require random access
> updates, it just positions entries in the order they happened to be added
> instead of sorting by their hash. Once you start updating it to indicate
> spent status all the exact same issues of TXO size and cache coherence on
> updates show up again, but now you're using a more complex bespoke data
> structure instead of a basic fundamental one.
Sorry, but I was replying to your statement:
> What you can't do with MMRs or the blockchain is make a compact proof that
> something is still in the utxo set, which is the whole point of utxo
> commitments.
So to be clear, do you agree or disagree with me that you *can* extract a
compact proof from a MMR that a given output is unspent?
I just want to make sure we're on the same page here before we discuss
performance characteristics.
--
https://petertodd.org 'peter'[:-1]@petertodd.org
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next prev parent reply other threads:[~2017-02-24 2:58 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-23 1:15 Peter Todd
2017-02-23 3:07 ` Bram Cohen
2017-02-23 7:41 ` Peter Todd
2017-02-23 17:53 ` Chris Priest
2017-02-23 18:19 ` Peter Todd
2017-02-23 18:28 ` G. Andrew Stone
2017-02-23 18:31 ` Peter Todd
2017-02-23 23:13 ` Bram Cohen
2017-02-23 23:51 ` Peter Todd
2017-02-24 0:49 ` Bram Cohen
2017-02-24 1:09 ` Peter Todd
2017-02-24 2:50 ` Bram Cohen
2017-02-24 2:58 ` Peter Todd [this message]
2017-02-24 3:02 ` Bram Cohen
2017-02-24 3:15 ` Peter Todd
2017-02-24 3:32 ` Bram Cohen
2017-02-24 4:36 ` Peter Todd
2017-02-24 22:20 ` Bram Cohen
2017-02-25 4:12 ` Peter Todd
2017-02-25 6:23 ` Bram Cohen
2017-02-28 16:43 ` G. Andrew Stone
2017-02-28 23:10 ` Bram Cohen
2017-02-28 23:24 ` Pieter Wuille
2017-03-01 1:47 ` Bram Cohen
2017-03-01 1:56 ` Peter Todd
2017-03-01 22:31 ` Peter Todd
2017-03-31 20:38 ` Bram Cohen
2017-04-01 10:18 ` praxeology_guy
2017-04-01 19:46 ` praxeology_guy
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