Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-1.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1S2tDi-0006qT-LB for bitcoin-development@lists.sourceforge.net; Wed, 29 Feb 2012 23:46:06 +0000 X-ACL-Warn: Received: from vps7135.xlshosting.net ([178.18.90.41]) by sog-mx-2.v43.ch3.sourceforge.com with esmtp (Exim 4.76) id 1S2tDh-0004nu-Or for bitcoin-development@lists.sourceforge.net; Wed, 29 Feb 2012 23:46:06 +0000 Received: by vps7135.xlshosting.net (Postfix, from userid 1000) id B6A7F60EA9; Thu, 1 Mar 2012 00:45:59 +0100 (CET) Date: Thu, 1 Mar 2012 00:45:59 +0100 From: Pieter Wuille To: Ben Reeves Message-ID: <20120229234558.GA6573@vps7135.xlshosting.net> References: <20120229232029.GA6073@vps7135.xlshosting.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120229232029.GA6073@vps7135.xlshosting.net> X-PGP-Key: http://sipa.ulyssis.org/pubkey.asc User-Agent: Mutt/1.5.20 (2009-06-14) X-Spam-Score: 1.2 (+) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (pieter.wuille[at]gmail.com) 0.0 DKIM_ADSP_CUSTOM_MED No valid author signature, adsp_override is CUSTOM_MED -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 1.2 NML_ADSP_CUSTOM_MED ADSP custom_med hit, and not from a mailing list X-Headers-End: 1S2tDh-0004nu-Or Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Duplicate transactions vulnerability 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, 29 Feb 2012 23:46:06 -0000 On Wed, Feb 29, 2012 at 11:00:42PM +0000, Ben Reeves wrote: > I'm not sure. What if they use a coinbase of a block that has already matured? Indeed; duplicate an old coinbase, fork chain without dupe, and spend the old coinbase. The 100-blocks maturity will not help against is. I'm not sure how you intend to fix DisconnectBlock() to prevent this in a backward- compatible way, though. -- Pieter