Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 47F86CDD for ; Wed, 9 Dec 2015 16:40:37 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-lf0-f49.google.com (mail-lf0-f49.google.com [209.85.215.49]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 9FC98171 for ; Wed, 9 Dec 2015 16:40:36 +0000 (UTC) Received: by lfs39 with SMTP id 39so38580015lfs.3 for ; Wed, 09 Dec 2015 08:40:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=g2WZxPQf2/e/t42w1k+vzVxEWcdXu/cSx6A66+w7+JM=; b=tOGHkVEbdRpV3lcJDYiSEYH4+xS7iFHRnre5fdWJ2w3T5PNRIEVftQYiTMtFukJUad 4J6oavUEpKCNfYNKGdeq9UDH3eZDwum61dT1kpO0L2jIXwk2v4YRAOTbJ1P2HCD/2tBC O85PXWQjSaPAH+wsm+QBG7CEae4Euzvz9S80qNhEqWs+jZX57LxFEyu0e0HC83OeEqfn pw13zjLXUut2sZr3fkSV8L2El9jPTFxum6pqDQ2DJuAkAXC9wKbhHVgQ5Q5Sf60xFbrg FaQss3ONDPKmfG/ztYz8SNyG16YM+5k8DFPrQqUFRIX6OClfKsx0C8LakamJJaJmny3W cZ/A== MIME-Version: 1.0 X-Received: by 10.25.27.147 with SMTP id b141mr2730644lfb.87.1449679234962; Wed, 09 Dec 2015 08:40:34 -0800 (PST) Received: by 10.25.22.95 with HTTP; Wed, 9 Dec 2015 08:40:34 -0800 (PST) In-Reply-To: References: <20151208110752.GA31180@amethyst.visucore.com> Date: Wed, 9 Dec 2015 11:40:34 -0500 Message-ID: From: Gavin Andresen To: Gregory Maxwell Content-Type: multipart/alternative; boundary=001a11401350d6a136052679bfde X-Spam-Status: No, score=-2.7 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,HTML_MESSAGE,RCVD_IN_DNSWL_LOW autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Cc: Bitcoin Dev Subject: Re: [bitcoin-dev] Capacity increases for the Bitcoin system. X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Development Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Dec 2015 16:40:37 -0000 --001a11401350d6a136052679bfde Content-Type: text/plain; charset=UTF-8 On Wed, Dec 9, 2015 at 3:03 AM, Gregory Maxwell via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org> wrote: > I think it would be logical to do as part of a hardfork that moved > commitments generally; e.g. a better position for merged mining (such > a hardfork was suggested in 2010 as something that could be done if > merged mining was used), room for commitments to additional block > back-references for compact SPV proofs, and/or UTXO set commitments. > Part of the reason to not do it now is that the requirements for the > other things that would be there are not yet well defined. For these > other applications, the additional overhead is actually fairly > meaningful; unlike the fraud proofs. > So just design ahead for those future uses. Make the merkle tree: root_in_block_header / \ tx_data_root other_root / \ segwitness_root reserved_for_future_use_root ... where reserved_for_future_use is zero until some future block version (or perhaps better, is just chosen arbitrarily by the miner and sent along with the block data until some future block version). That would minimize future disruption of any code that produced or consumed merkle proofs of the transaction data or segwitness data, especially if the reserved_for_future_use_root is allowed to be any arbitrary 256-bit value and not a constant that would get hard-coded into segwitness-proof-checking code. -- -- Gavin Andresen --001a11401350d6a136052679bfde Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On W= ed, Dec 9, 2015 at 3:03 AM, Gregory Maxwell via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote:
I think it would be logical to do as part of a hardfork that moved<= br> commitments generally; e.g. a better position for merged mining (such
a hardfork was suggested in 2010 as something that could be done if
merged mining was used), room for commitments to additional block
back-references for compact SPV proofs, and/or UTXO set commitments.
Part of the reason to not do it now is that the requirements for the
other things that would be there are not yet well defined. For these
other applications, the additional overhead is actually fairly
meaningful; unlike the fraud proofs.

So= just design ahead for those future uses. Make the merkle tree:


=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0root_in= _block_header
=C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0/ =C2=A0 =C2=A0 =C2=A0\
=C2=A0 tx_data_root =C2=A0 =C2=A0 =C2=A0other_= root
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0/ = =C2=A0 =C2=A0 =C2=A0 \
=C2=A0 =C2=A0 =C2=A0= =C2=A0 segwitness_root =C2=A0 =C2=A0 reserved_for_future_use_root

... where rese= rved_for_future_use is zero until some future block version (or perhaps bet= ter, is just chosen arbitrarily by the miner and sent along with the block = data until some future block version).

=
That would minimize future disruption of a= ny code that produced or consumed merkle proofs of the transaction data or = segwitness data, especially if the reserved_for_future_use_root is allowed = to be any arbitrary 256-bit value and not a constant that would get hard-co= ded into segwitness-proof-checking code.

--
--
= Gavin Andresen

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