From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 4AC10D09 for ; Tue, 8 Dec 2015 19:08:59 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-io0-f178.google.com (mail-io0-f178.google.com [209.85.223.178]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 3E5D3E5 for ; Tue, 8 Dec 2015 19:08:58 +0000 (UTC) Received: by ioc74 with SMTP id 74so34313530ioc.2 for ; Tue, 08 Dec 2015 11:08:57 -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:cc :content-type; bh=acEMsctgIx0T9qMvLgaBqN2vnbvue+8ssqf947s7O4Y=; b=GhuvqGbf98UJHxvOzv7IXETrbsInbxm08JAT3lYRtHhm8Vvkhms26ucJoSqlD+QUCo 5RRb8FxChBYFsLGr4dXD+y5SzR2cSdPfZjvj5EPfD/o0jxFAIAQ63M68bJZrfNLPSw9M lrdy17e5rBKkN+K77xOON/o+05C8IfdYpii0mF6L6XLtoSIyUfKoYY/9VCN8tLyT/Vub NIl+l5qQPvo0dIpi0hTKbIzbhGtP8PbI1oxQMFkIlp1VQcPuij+PlUHRyLjLG2CokKFW vy4fqANeEsJg+BWd7Gle1ROu5dHBAJJ3K2cOTfiUKYRLcRa5tSb/cx+Sxpc0VujEY0t+ xqkg== MIME-Version: 1.0 X-Received: by 10.107.163.79 with SMTP id m76mr1693608ioe.109.1449601737632; Tue, 08 Dec 2015 11:08:57 -0800 (PST) Received: by 10.79.113.156 with HTTP; Tue, 8 Dec 2015 11:08:57 -0800 (PST) In-Reply-To: References: <20151208110752.GA31180@amethyst.visucore.com> <5666FD8D.8050201@openbitcoinprivacyproject.org> Date: Tue, 8 Dec 2015 19:08:57 +0000 Message-ID: From: Tier Nolan Cc: Bitcoin Dev Content-Type: multipart/alternative; boundary=001a11402acaa3308d052667b402 X-Spam-Status: No, score=-0.2 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, HTML_MESSAGE, MALFORMED_FREEMAIL, MISSING_HEADERS,RCVD_IN_DNSWL_LOW autolearn=no version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org 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: Tue, 08 Dec 2015 19:08:59 -0000 --001a11402acaa3308d052667b402 Content-Type: text/plain; charset=UTF-8 On Tue, Dec 8, 2015 at 5:41 PM, Mark Friedenbach via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org> wrote: > A far better place than the generation transaction (which I assume means > coinbase transaction?) is the last transaction in the block. That allows > you to save, on average, half of the hashes in the Merkle tree. > This trick can be improved by only using certain tx counts. If the number of transactions is limited to a power of 2 (other than the extra transactions), then you get a path of length zero. The number of non-zero bits in the tx count determings how many digests are required. https://github.com/TierNolan/bips/blob/aux_header/bip-aux-header.mediawiki This gets the benefit of a soft-fork, while also keeping the proof lengths small. The linked bip has a 105 byte overhead for the path. The cost is that only certain transaction counts are allowed. In the worst case, 12.5% of transactions would have to be left in the memory pool. This means around 7% of transactions would be delayed until the next block. Blank transactions (or just transactions with low latency requirements) could be used to increase the count so that it is raised to one of the valid numbers. Managing the UTXO set to ensure that there is at least one output that pays to OP_TRUE is also a hassle. --001a11402acaa3308d052667b402 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On T= ue, Dec 8, 2015 at 5:41 PM, Mark Friedenbach via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote:
A far better= place than the generation transaction (which I assume means coinbase trans= action?) is the last transaction in the block. That allows you to save, on = average, half of the hashes in the Merkle tree.
=
This trick can be improved by only using certain tx counts.=C2=A0= If the number of transactions is limited to a power of 2 (other than the e= xtra transactions), then you get a path of length zero.

The number of non-zero bits in the tx count determings= how many digests are required.

https://github.com/TierNolan/bips/blob/aux_header/bip-aux-header.m= ediawiki

This gets the benefit = of a soft-fork, while also keeping the proof lengths small.=C2=A0 The linke= d bip has a 105 byte overhead for the path.

The cost is that only certain transaction counts are allowed.=C2= =A0 In the worst case, 12.5% of transactions would have to be left in the m= emory pool.=C2=A0 This means around 7% of transactions would be delayed unt= il the next block.

Blank transactio= ns (or just transactions with low latency requirements) could be used to in= crease the count so that it is raised to one of the valid numbers.

<= /div>
Managing the UTXO set to ensure that there = is at least one output that pays to OP_TRUE is also a hassle.
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