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From: Bram Cohen <bram@bittorrent.com>
Date: Thu, 23 Feb 2017 19:02:36 -0800
Message-ID: <CA+KqGkq7gavAnAk-tcA+gxL2sWpv3ENhEmHrQHaPdyAsKrLjGg@mail.gmail.com>
To: Peter Todd <pete@petertodd.org>
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Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] A Better MMR Definition
Precedence: list

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On Thu, Feb 23, 2017 at 6:58 PM, Peter Todd <pete@petertodd.org> wrote:

>
> 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?
>

After wading through your logic on how updates are done, I agree that that
can be done, but apples to apples compact proofs can also be done in a utxo
commitment, and proofs of the validity of updates can be done in a utxo
commitment, so there isn't any performance advantage to all that extra
complexity.

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<div dir=3D"ltr"><div class=3D"gmail_extra"><div class=3D"gmail_quote">On T=
hu, Feb 23, 2017 at 6:58 PM, Peter Todd <span dir=3D"ltr">&lt;<a href=3D"ma=
ilto:pete@petertodd.org" target=3D"_blank">pete@petertodd.org</a>&gt;</span=
> wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;bo=
rder-left:1px #ccc solid;padding-left:1ex"><div class=3D"HOEnZb"><div class=
=3D"h5"><br></div></div>So to be clear, do you agree or disagree with me th=
at you *can* extract a<br>
compact proof from a MMR that a given output is unspent?<br></blockquote><d=
iv><br></div><div>After wading through your logic on how updates are done, =
I agree that that can be done, but apples to apples compact proofs can also=
 be done in a utxo commitment, and proofs of the validity of updates can be=
 done in a utxo commitment, so there isn&#39;t any performance advantage to=
 all that extra complexity.</div></div></div></div>

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