Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 199B2BC7 for ; Sat, 27 Jun 2015 18:02:08 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-wi0-f174.google.com (mail-wi0-f174.google.com [209.85.212.174]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 0CEF6279 for ; Sat, 27 Jun 2015 18:02:07 +0000 (UTC) Received: by wiga1 with SMTP id a1so40650094wig.0 for ; Sat, 27 Jun 2015 11:02:05 -0700 (PDT) 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=Pbhq31jIyepJw+dNyvFXTdIdBZnk16yZivKdN32Gt80=; b=C1dhEbnQ7xO/HV2MW/DrJliKsKwPikdLkUHwyaoZ4eN2a9Fy3QwfHYO5BovgQuoe+p vFy4Yno7Ve2shL25eXIwbEomQsJ9aHdLzULhUx67Kk1iZIUZfm74+rxcpuJOIhbJqh0n QXQ0CmIHvgE7GCTm0A3ULRWaP9ojN8hjUSyhSt4c3KcsAUHGn1Dx2nN4aMxauta0eMTP n7y/IlBcTimOSvDOaZN2sNB6iS4jpXYY6Xe833qJapNZDGFlviO0AYQiMbdzNNMQ09FK 6n7d3FtW3ImgW+f+k9ktPnLHbZy9gvPFP3sauGc4ag8fDYuycQZsA6/Z+lAv8Vpz6amQ NohA== MIME-Version: 1.0 X-Received: by 10.180.84.170 with SMTP id a10mr7744765wiz.52.1435428125887; Sat, 27 Jun 2015 11:02:05 -0700 (PDT) Received: by 10.27.171.143 with HTTP; Sat, 27 Jun 2015 11:02:05 -0700 (PDT) In-Reply-To: <20150627173451.GA28181@muck> References: <20150627163731.GA12820@muck> <20150627173451.GA28181@muck> Date: Sat, 27 Jun 2015 14:02:05 -0400 Message-ID: From: Jameson Lopp To: Peter Todd Content-Type: multipart/alternative; boundary=f46d041827e68b53b6051983a74d 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@lists.linuxfoundation.org Subject: Re: [bitcoin-dev] A Proposed Compromise to the Block Size Limit 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: Sat, 27 Jun 2015 18:02:08 -0000 --f46d041827e68b53b6051983a74d Content-Type: text/plain; charset=UTF-8 On Sat, Jun 27, 2015 at 1:34 PM, Peter Todd wrote: > On Sat, Jun 27, 2015 at 01:25:14PM -0400, Michael Naber wrote: > > Global network consensus means that there is global network recognition > > that a particular transaction has occurred and is irreversible. The > > off-chain solutions you describe, while probably useful for other > purposes, > > do not exhibit this characteristic and so they are not global network > > consensus networks. > > Hub-and-spoke payment channels and the Lightning network are not > off-chain solutions, they are ways to more efficiently use on-chain > transactions to achive the goal of moving assets from point a to point > b, resulting in more economic transactions being done with fewer - but > not zero! - blockchain transactions. > > Off-chain transaction systems such as Changetip allow economic > transactions to happen with no blockchain transactions at all. > > > Bitcoin Core scales as O(N), where N is the number of transactions. Can > we > > do better than this while still achieving global consensus? > > No, Bitcoin the network scales with O(n^2) with your above criteria, as > each node creates k transactions, thus each node has to verify k*n > transactions, resulting in O(n^2) total work. > > For Bitcoin to have O(n) scaling you have to assume that the number of > validation nodes doesn't scale with the number of users, thus resulting > in a system where users trust others to do validation for them. That is > not a global consensus system; that's a trust-based system. > > Why does it matter what the "total work" of the network is? Anyone who is participating as a node on the network only cares about the resources required to run their own node, not the resources everyone else needs to run their nodes. Also, no assumption needed, it is quite clear that the number of nodes is not scaling along with the number of users. If anything it appears to be inversely proportional. > There's nothing inherently wrong with that, but why change Bitcoin > itself into a trust-based system, when you can preserve the global > consensus functionality, and built a trust-based system on top of it? > > -- > 'peter'[:-1]@petertodd.org > 0000000000000000007fc13ce02072d9cb2a6d51fae41fefcde7b3b283803d24 > > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > > --f46d041827e68b53b6051983a74d Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On Sat, Jun 27, 2015 at 1:34 PM, Peter Todd <pete@petertodd.org&g= t; wrote:
On Sat,= Jun 27, 2015 at 01:25:14PM -0400, Michael Naber wrote:
> Global network consensus means that there is global network recognitio= n
> that a particular transaction has occurred and is irreversible. The > off-chain solutions you describe, while probably useful for other purp= oses,
> do not exhibit this characteristic and so they are not global network<= br> > consensus networks.

Hub-and-spoke payment channels and the Lightning network are not
off-chain solutions, they are ways to more efficiently use on-chain
transactions to achive the goal of moving assets from point a to point
b, resulting in more economic transactions being done with fewer - but
not zero! - blockchain transactions.

Off-chain transaction systems such as Changetip allow economic
transactions to happen with no blockchain transactions at all.

> Bitcoin Core scales as O(N), where N is the number of transactions. Ca= n we
> do better than this while still achieving global consensus?

No, Bitcoin the network scales with O(n^2) with your above criteria,= as
each node creates k transactions, thus each node has to verify k*n
transactions, resulting in O(n^2) total work.

For Bitcoin to have O(n) scaling you have to assume that the number of
validation nodes doesn't scale with the number of users, thus resulting=
in a system where users trust others to do validation for them. That is
not a global consensus system; that's a trust-based system.


Why does it matter what the "tota= l work" of the network is? Anyone who is participating as a node on th= e network only cares about the resources required to run their own node, no= t the resources everyone else needs to run their nodes.

A= lso, no assumption needed, it is quite clear that the number of nodes is no= t scaling along with the number of users. If anything it appears to be inve= rsely proportional.
=C2=A0

--
'peter'[:-1]@petertodd.org
0000000000000000007fc13ce02072d9cb2a6d51fae41fefcde7b3b283803d24

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bitcoin-dev mailing list
bitcoin-dev@lists.= linuxfoundation.org
https://lists.linuxfoundation.org/mail= man/listinfo/bitcoin-dev


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