From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1Wczel-0006Yr-QZ for bitcoin-development@lists.sourceforge.net; Wed, 23 Apr 2014 16:04:19 +0000 Received-SPF: pass (sog-mx-2.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.213.173 as permitted sender) client-ip=209.85.213.173; envelope-from=christophe.biocca@gmail.com; helo=mail-ig0-f173.google.com; Received: from mail-ig0-f173.google.com ([209.85.213.173]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1Wczel-0002aH-0g for bitcoin-development@lists.sourceforge.net; Wed, 23 Apr 2014 16:04:19 +0000 Received: by mail-ig0-f173.google.com with SMTP id hl10so4509262igb.0 for ; Wed, 23 Apr 2014 09:04:13 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.43.75.2 with SMTP id yy2mr38269340icb.54.1398269053677; Wed, 23 Apr 2014 09:04:13 -0700 (PDT) Received: by 10.64.102.136 with HTTP; Wed, 23 Apr 2014 09:04:13 -0700 (PDT) In-Reply-To: References: Date: Wed, 23 Apr 2014 12:04:13 -0400 Message-ID: From: Christophe Biocca To: Bitcoin Dev Content-Type: text/plain; charset=UTF-8 X-Spam-Score: -1.6 (-) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (christophe.biocca[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature X-Headers-End: 1Wczel-0002aH-0g Subject: Re: [Bitcoin-development] Coinbase reallocation to discourage Finney attacks X-BeenThere: bitcoin-development@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 23 Apr 2014 16:04:20 -0000 It's not necessary that this "coinbase retribution" be either profitable or risk-free for this scheme to work. I think we should separate out the different layers of the proposal: 1. Attacking the coinbase instead of orphaning allows for 100 blocks' time for a consensus to be reached, rather than 10 minutes. This allows for human verification/intervention if needed (orphaning decisions would almost always need to be automated, due to the short timeframe). This is a useful insight, and I don't think it's been brought up before. 2. The original specification of how it's done (redistribution, no cost to voting) does seem exploitable. This can be fixed by reducing the incentive (burning instead of redistributing) and/or adding a risk to the orphaning attempts (a vote that fails destroys X bitcoins' worth from each voting block's own coinbase). The incentives can be tailored to mirror those of orphaning a block, to reduce the risk of abuse. Then the only difference from orphaning are 1) More limited rewriting of history (only the coinbase, vs all transactions in the block), and 2) More time to coordinate a response. 3. This proposal may be used for things other than punishing double-spend pools. In fact it might be used to punish miners for doing anything a significant percentage of hashpower dislikes (large OP_RETURNs, large blocks, gambling transactions, transactions banned by a government). But we can make the threshold higher than 51%, so that this doesn't turn into a significant risk (if 75% of hashpower is willing to enforce a rule, we're already likely to see it enforced through orphaning). On Wed, Apr 23, 2014 at 11:38 AM, Alex Mizrahi wrote: > >> >> And it still would. Non-collusive miners cast votes based on the outcome >> of their own attempts to double spend. > > > Individually rational strategy is to vote for coinbase reallocation on every > block. > > Yes, in that case nobody will get reward. It is similar to prisoner's > dilemma: equilibrium has worst pay-off. > In practice that would mean that simple game-theoretic models are no longer > applicable, as they lead to absurd results. > >> >> I'm using it in the same sense Satoshi used it. Honest miners work to >> prevent double spends. That's the entire justification for their existence. >> Miners that are deliberately trying to double spend are worse than useless. > > > Miners work to get rewards. > It absolutely doesn't matter whether they are deliberately trying to > double-spend or not: they won't be able to double-spend without a collusion. > > ------------------------------------------------------------------------------ > Start Your Social Network Today - Download eXo Platform > Build your Enterprise Intranet with eXo Platform Software > Java Based Open Source Intranet - Social, Extensible, Cloud Ready > Get Started Now And Turn Your Intranet Into A Collaboration Platform > http://p.sf.net/sfu/ExoPlatform > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development >