From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-3.v43.ch3.sourceforge.com ([172.29.43.193] helo=mx.sourceforge.net) by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1YPWvf-0006rW-C3 for bitcoin-development@lists.sourceforge.net; Sun, 22 Feb 2015 13:50:39 +0000 X-ACL-Warn: Received: from resqmta-ch2-08v.sys.comcast.net ([69.252.207.40]) by sog-mx-3.v43.ch3.sourceforge.com with esmtps (TLSv1:AES128-SHA:128) (Exim 4.76) id 1YPWvd-0003IP-Rx for bitcoin-development@lists.sourceforge.net; Sun, 22 Feb 2015 13:50:39 +0000 Received: from resomta-ch2-12v.sys.comcast.net ([69.252.207.108]) by resqmta-ch2-08v.sys.comcast.net with comcast id vRqF1p0052LrikM01RqYql; Sun, 22 Feb 2015 13:50:32 +0000 Received: from crushinator.localnet ([IPv6:2601:6:4800:47f:1e4e:1f4d:332c:3bf6]) by resomta-ch2-12v.sys.comcast.net with comcast id vRqW1p00M2JF60R01RqY4l; Sun, 22 Feb 2015 13:50:32 +0000 From: Matt Whitlock To: Natanael Date: Sun, 22 Feb 2015 08:50:30 -0500 Message-ID: <2953246.T2DHreG0Tu@crushinator> User-Agent: KMail/4.14.3 (Linux/3.17.8-gentoo-r1; KDE/4.14.5; x86_64; ; ) In-Reply-To: References: <20150222123428.GA6570@savin.petertodd.org> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Spam-Score: 0.0 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [69.252.207.40 listed in list.dnswl.org] 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: 1YPWvd-0003IP-Rx Cc: bitcoin-development@lists.sourceforge.net Subject: Re: [Bitcoin-development] alternate proposal opt-in miner takes double-spend (Re: replace-by-fee v0.10.0rc4) 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: Sun, 22 Feb 2015 13:50:39 -0000 On Sunday, 22 February 2015, at 2:29 pm, Natanael wrote: > In other words, you are unprotected and potentially at greater risk if you > create a transaction depending on another zero-confirmation transaction. This happened to one of the merchants at the Bitcoin 2013 conference in San Jose. They sold some T-shirts and accepted zero-confirmation transactions. The transactions depended on other unconfirmed transactions, which never confirmed, so this merchant never got their money. I keep telling people not to accept transactions with zero confirmations, but no one listens.