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 DF0EAFA7 for ; Mon, 28 Dec 2015 20:26:44 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-yk0-f173.google.com (mail-yk0-f173.google.com [209.85.160.173]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 4AD05108 for ; Mon, 28 Dec 2015 20:26:44 +0000 (UTC) Received: by mail-yk0-f173.google.com with SMTP id x67so111458383ykd.2 for ; Mon, 28 Dec 2015 12:26:44 -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=ljsf0rko1ikx9NEbe2z+iIzdBS/Ybd1+ZR5U49Qt72Q=; b=s01TrYfEc3LNWwVtsieVQJ8P+ScAcY+ujwIhIz/Cmg8nRQPm4zb3kjCA6DPsEaGnpM frZnZjwP7t2vwfZqqY1R2ULMpaojBqJ5gwvjj8KpbxuAmgvw8D92cDUk0iKbf2GgfJs8 nXuuZTx2JsvInEFuoDUR2Ii2yX+8j2t6hg/RC7ZrnoEu21hJ3jO1556hrCRgxx5Xx0Eg WOgjAAzm/7pWG1PmaFehc/I7JFRSYb+BVlCEKTONKbmqiEosSCR0sILsiqn+evpNLqJ1 eFoNAFNXH5PUU5KjYYU3dNE1quTAJnOOHrOPjxY9chxgaZOJWgNVmlxcprTwGx2vSiVg LIhQ== MIME-Version: 1.0 X-Received: by 10.129.57.135 with SMTP id g129mr41023929ywa.244.1451334403583; Mon, 28 Dec 2015 12:26:43 -0800 (PST) Received: by 10.129.132.211 with HTTP; Mon, 28 Dec 2015 12:26:43 -0800 (PST) In-Reply-To: <20151228191228.GC12298@muck> References: <20151219184240.GB12893@muck> <4882BD35-D890-4860-9222-5C23AEB6AE89@mattcorallo.com> <20151220044450.GA23942@muck> <20151228191228.GC12298@muck> Date: Mon, 28 Dec 2015 15:26:43 -0500 Message-ID: From: Ivan Brightly To: Peter Todd Content-Type: multipart/alternative; boundary=001a114c78fe9377ed0527fb1f05 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 X-Mailman-Approved-At: Mon, 28 Dec 2015 21:27:00 +0000 Cc: Bitcoin Dev Subject: Re: [bitcoin-dev] We need to fix the block withholding attack 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: Mon, 28 Dec 2015 20:26:45 -0000 --001a114c78fe9377ed0527fb1f05 Content-Type: text/plain; charset=UTF-8 > > On Mon, Dec 28, 2015 at 2:12 PM, Peter Todd via bitcoin-dev < > bitcoin-dev@lists.linuxfoundation.org> wrote: > Far more concerning is network propagation effects between large and > small miners. For that class of issues, if you are in an environemnt > where selfish mining is possible - a fairly flat, easily DoS/sybil > attacked network topology - the profitability difference between small > and large miners even *without* attacks going on is a hugely worrying > problem. OTOH, if you're blocksize is small enough that propagation time > is negligable to profitability, then selfish mining attacks with <30% > hashing power aren't much of a concern - they'll be naturally defeated > by anti-DoS/anti-sybil measures. > Let's agree that one factor in mining profitability is bandwidth/network reliability/stability. Why focus on that vs electricity contracts or vertically integrated chip manufacturers? Surely, sufficient network bandwidth is a more broadly available commodity than <$0.02/kwh electricity, for example. I'm not sure that your stranded hydroelectric miner is any more desirable than thousands of dorm room miners with access to 10gbit university connections and free electricity. --001a114c78fe9377ed0527fb1f05 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On Mon, Dec 28, 2015 at 2:12 PM, Peter Todd via bitcoin-dev=C2= =A0<bitcoin-dev@lists.linuxfoundation.org>=C2=A0wrote:
Far more concerning is network propagation effects between large and
small miners. For that class of issues, if you are in an environemnt
where selfish mining is possible - a fairly flat, easily DoS/sybil
attacked network topology - the profitability difference between small
and large miners even *without* attacks going on is a hugely worrying
problem. OTOH, if you're blocksize is small enough that propagation tim= e
is negligable to profitability, then selfish mining attacks with <30% hashing power aren't much of a concern - they'll be naturally defea= ted
by anti-DoS/anti-sybil measures.

Let= 9;s agree that one factor in mining profitability is bandwidth/network reli= ability/stability. Why focus on that vs electricity contracts or vertically= integrated chip manufacturers? Surely, sufficient network bandwidth is a m= ore broadly available commodity than <$0.02/kwh electricity, for example= . I'm not sure that your stranded hydroelectric miner is any more desir= able than thousands of dorm room miners with access to 10gbit university co= nnections and free electricity.
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