Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 8F792B22 for ; Fri, 24 Feb 2017 03:32:45 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-it0-f44.google.com (mail-it0-f44.google.com [209.85.214.44]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 0258A193 for ; Fri, 24 Feb 2017 03:32:44 +0000 (UTC) Received: by mail-it0-f44.google.com with SMTP id y135so9170040itc.1 for ; Thu, 23 Feb 2017 19:32:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bittorrent-com.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=kou25u+DEOIzHFibq9or52hiCsqpptHXFiNPFg8GSa4=; b=rqLpVhwdi0/V8qojj/LwV7V2CdP6EK3LdF4/Y9+UNek0mmKqFWnJr0ZNIidR/J0NSf TMMgEy/Ao+XxbCx2W67M1SJotOOA9777+MQaeJRzsRhjDOZi1yp1LpmSDo+TDgX6/9X8 2zKbppg/mttSnfrHu/SqgF6OhAPm3Qxn+MpoqodHbmtfvLOUBwSYRIDxc738K5GsDHEE 3+XO7XaWWJYEfLzcfPZ457N3T2BPm6qVAaZ1AHFGqOWhJlBa+LkF+J8Ktrjr/4KLQcaC B6nL/z/x10kYPlIcOuzEiBdIy5jQ2S2adn/1BOdS55KxKb0jTksavMrRFs97FbsaZzYE FtAg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=kou25u+DEOIzHFibq9or52hiCsqpptHXFiNPFg8GSa4=; b=XIdgBhFLiuqIBM4ki9uA/SDlv1IDAAdzI1rEjEVQdospVswRlYfCL6V4A7gyCUyCKw FmM9A1PhimI9m4Nbokfppn2Unh57I8bzXQ6NlvvQVKgkbJ2++OLe4193Uepr2GbrZDfJ FJ4k2YcBUigN0G359wPIir2bc7GnrKo/Ts4KnBKwSHsD0MredzZIpHZ+NOwaqp3x2DkU SWjSGtFrXCgpy4TOahOPTYFlI4MsfHjawdm8K0bI48UU+bt9sIWMAmwOys+HC/WoCdNE JhVpTYaReMeCzF7aRW9RqEbK5C8iyTBLSZjiKGZyBnJSYUTPUgunliKLDV7onuedIVCB X2MQ== X-Gm-Message-State: AMke39mEHa5/sJrZ4CL1c+sXlofp6G3+2/iJsJg3V78Ci/zdXJWxG4IQZlaycIIG1NBRa7Hf8PCJAQrBANaGHTq9 X-Received: by 10.36.25.83 with SMTP id b80mr862508itb.98.1487907164378; Thu, 23 Feb 2017 19:32:44 -0800 (PST) MIME-Version: 1.0 Received: by 10.36.73.150 with HTTP; Thu, 23 Feb 2017 19:32:43 -0800 (PST) In-Reply-To: <20170224031531.GA32118@savin.petertodd.org> References: <20170223011506.GC905@savin.petertodd.org> <20170223235105.GA28497@savin.petertodd.org> <20170224010943.GA29218@savin.petertodd.org> <20170224025811.GA31911@savin.petertodd.org> <20170224031531.GA32118@savin.petertodd.org> From: Bram Cohen Date: Thu, 23 Feb 2017 19:32:43 -0800 Message-ID: To: Peter Todd Content-Type: multipart/alternative; boundary=001a11440182fdfdd905493e618e X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, HTML_MESSAGE, RCVD_IN_DNSWL_LOW, RCVD_IN_SORBS_SPAM autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Cc: Bitcoin Protocol Discussion Subject: Re: [bitcoin-dev] A Better MMR Definition X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Feb 2017 03:32:45 -0000 --001a11440182fdfdd905493e618e Content-Type: text/plain; charset=UTF-8 On Thu, Feb 23, 2017 at 7:15 PM, Peter Todd 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. --001a11440182fdfdd905493e618e Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On T= hu, Feb 23, 2017 at 7:15 PM, Peter Todd <pete@petertodd.org> wrote:

Glad we're on the same page with regard to what's possi= ble in TXO commitments.

Secondly, am I correct in saying your UTXO commitments scheme requires rand= om
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 o= rdering
to be?

The ordering is by the bits in t= he hash. Technically it's a Patricia Trie. I'm using 'merkle tr= ee' to refer to basically anything with a hash root.
=C2=A0
Maybe more specifically, what exact valu= es do you propose to be in the set?

<= br>
That is unspecified in the implementation, it just takes a 25= 6 bit value which is presumably a hash of something. The intention is to na= il down a simple format and demonstrate good performance and leave those se= mantics to a higher layer. The simplest thing would be to hash together the= txid and output number.
--001a11440182fdfdd905493e618e--