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 A5684ECB for ; Fri, 11 Sep 2015 16:27:27 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-wi0-f169.google.com (mail-wi0-f169.google.com [209.85.212.169]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id E951F1D9 for ; Fri, 11 Sep 2015 16:27:26 +0000 (UTC) Received: by wiclk2 with SMTP id lk2so64397188wic.1 for ; Fri, 11 Sep 2015 09:27:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:date:message-id:subject:from:to:content-type; bh=Hvfnv2gIkUk+KKg/g8wc7x5hgxbPI+wKcUdMHUxaqj0=; b=xz8o86I8AtGNEew4poeNvyibl/JHzfXitIqrryl8RK5Zr+8sBnBrz7ey71jHCoVBSQ sNggynTEBLvjV0X0Tmorfow39igzc/j4ySsOY8RcxNxRwIj5RRI4SclKqZkc9JhYPV/Z XqkOWD1l5uGzmvf6WCQQcL47RPBjFK/rgsc5DcZu2j5D1WqhI9Q1ydF4Z1ghM6+6vjeu gH4DZnNbNRxDUQ7jNK99bhGA5botYMOHJBdY1gZp0/8pFnuixx2PY5DJODmai6NJNuhv yOMT6vHkaGZ0QMVyAwwBR5y7dTmZObjjE4/HWE/1BhIK5MlXpferVguYJmf26EfpJ9rz 4uxg== MIME-Version: 1.0 X-Received: by 10.180.187.244 with SMTP id fv20mr16287161wic.23.1441988845568; Fri, 11 Sep 2015 09:27:25 -0700 (PDT) Sender: dscotese@gmail.com Received: by 10.27.211.132 with HTTP; Fri, 11 Sep 2015 09:27:25 -0700 (PDT) Date: Fri, 11 Sep 2015 09:27:25 -0700 X-Google-Sender-Auth: q-9AH80hZbvF5m5C3dsvzqJdyZ4 Message-ID: From: Dave Scotese To: Bitcoin Dev Content-Type: multipart/alternative; boundary=001a11c37e46e90773051f7b30ef X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,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 Subject: [bitcoin-dev] Bitcoin Days Destroyed as block selection heuristic 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: Fri, 11 Sep 2015 16:27:27 -0000 --001a11c37e46e90773051f7b30ef Content-Type: text/plain; charset=UTF-8 Rather than (promising to, and when they don't actually, at least pretending to) use the first-seen block, I propose that a more sophisticated method of choosing which of two block solutions to accept. Essentially, a miner receiving two solutions at the same height would compute a weighted sum of bitcoin-days-destroyed (transactions received earlier get higher weights) of whatever transactions are in a block *and also* were in the miner's mempool *before* the first solution arrived. Whichever block has more wins. This strategy avoids allowing miners to use private transactions to mess with the blockchain. It also makes an empty block far less attractive because it is easily replaced, all the way until the next block locks it in. Any block-selection heuristic can be gamed, but I believe that using a weighted sum of BTCDD is harder to game than using block propagation timing. I asked Can Bitcoin Days Destroyed be a better resolution mechanism for competing blocks? on the stackexchange bitcoin site in order to collect objections to and problems with this idea, and have not found any that I haven't addressed. The best objection is that *maybe* empty blocks and selfish mining are either good for bitcoin, or else they are so minimally bad that no effort ought to be expended in preventing them. If anyone here thinks this is a good idea, and no one can offer reasons it's a bad idea, I will probably start working on an implementation. I'm really slow though, so ping me if it looks like fun to you. notplato --001a11c37e46e90773051f7b30ef Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Rather than (promising to, and when they don't ac= tually, at least pretending to) use the first-seen block, I propose that a = more sophisticated method of choosing which of two block solutions to accep= t.=C2=A0 Essentially, a miner receiving two solutions at the same height wo= uld compute a weighted sum of bitcoin-days-destroyed (transactions received= earlier get higher weights) of whatever transactions are in a block and= also were in the miner's mempool before the first solution = arrived.=C2=A0 Whichever block has more wins.

This strategy av= oids allowing miners to use private transactions to mess with the blockchai= n.=C2=A0 It also makes an empty block far less attractive because it is eas= ily replaced, all the way until the next block locks it in.=C2=A0 Any block= -selection heuristic can be gamed, but I believe that using a weighted sum = of BTCDD is harder to game than using block propagation timing.

I asked Can Bitcoin Days Destroyed be a better resolution mechanis= m for competing blocks? on the stackexchange bitcoin site in order to c= ollect objections to and problems with this idea, and have not found any th= at I haven't addressed.=C2=A0 The best objection is that maybe e= mpty blocks and selfish mining are either good for bitcoin, or else they ar= e so minimally bad that no effort ought to be expended in preventing them.<= br>
If anyone here thinks this is a good idea, and no one can= offer reasons it's a bad idea, I will probably start working on an imp= lementation.=C2=A0 I'm really slow though, so ping me if it looks like = fun to you.

notplato
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