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-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1WctwL-0004ud-Bq for bitcoin-development@lists.sourceforge.net; Wed, 23 Apr 2014 09:58:05 +0000 Received-SPF: pass (sog-mx-2.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.212.170 as permitted sender) client-ip=209.85.212.170; envelope-from=andyparkins@gmail.com; helo=mail-wi0-f170.google.com; Received: from mail-wi0-f170.google.com ([209.85.212.170]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1WctwK-0005VJ-K7 for bitcoin-development@lists.sourceforge.net; Wed, 23 Apr 2014 09:58:05 +0000 Received: by mail-wi0-f170.google.com with SMTP id bs8so4285596wib.3 for ; Wed, 23 Apr 2014 02:57:58 -0700 (PDT) X-Received: by 10.180.104.5 with SMTP id ga5mr985634wib.47.1398247078429; Wed, 23 Apr 2014 02:57:58 -0700 (PDT) Received: from grissom.localnet ([91.84.15.31]) by mx.google.com with ESMTPSA id vp5sm766400wjc.31.2014.04.23.02.57.57 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 23 Apr 2014 02:57:57 -0700 (PDT) From: Andy Parkins To: bitcoin-development@lists.sourceforge.net Date: Wed, 23 Apr 2014 10:57:53 +0100 User-Agent: KMail/1.13.7 (Linux/3.2.0-1-686-pae; KDE/4.8.4; i686; ; ) References: In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Message-Id: <201404231057.54387.andyparkins@gmail.com> 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 (andyparkins[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: 1WctwK-0005VJ-K7 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 09:58:05 -0000 On Wednesday 23 Apr 2014 08:55:30 Mike Hearn wrote: > Even with their woeful security many merchants see <1-2% credit card > chargeback rates, and chargebacks can be disputed. In fact merchants win > about 40% of chargeback disputes. So if N was only, say, 5%, and there > was a large enough population of users who were systematically trying to > defraud merchants, we'd already be having worse security than magstripe > credit cards. EMV transactions have loss rates in the noise, so for > merchants who take those Bitcoin would be dramatically less secure. Just pedantry: 100% of credit card transactions _can_ be fradulantly charged back but arent. In fact, only 2% are ever attempted. If N was 5%, then only 5% of bitcoin transactions _could_ be fraudulantly "charged back"; so then why wouldn't only 2% of those bitcoin transactions be fraudulant too, just as in the CC case? The comparison would then be 2% chargebacks for credit cards, equivalent to 0.1% (5%*2%) for bitcoin. Not that I think that makes anything else you say invalid. Andy -- Dr Andy Parkins andyparkins@gmail.com