Received: from sog-mx-1.v43.ch3.sourceforge.com ([172.29.43.191] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1UZdlb-0007Gl-8a for bitcoin-development@lists.sourceforge.net; Tue, 07 May 2013 09:00:59 +0000 Received-SPF: pass (sog-mx-1.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.219.53 as permitted sender) client-ip=209.85.219.53; envelope-from=mh.in.england@gmail.com; helo=mail-oa0-f53.google.com; Received: from mail-oa0-f53.google.com ([209.85.219.53]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1UZdla-00006H-AM for bitcoin-development@lists.sourceforge.net; Tue, 07 May 2013 09:00:59 +0000 Received: by mail-oa0-f53.google.com with SMTP id g12so318790oah.12 for ; Tue, 07 May 2013 02:00:53 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.182.226.136 with SMTP id rs8mr301997obc.50.1367917252988; Tue, 07 May 2013 02:00:52 -0700 (PDT) Sender: mh.in.england@gmail.com Received: by 10.76.167.169 with HTTP; Tue, 7 May 2013 02:00:52 -0700 (PDT) In-Reply-To: <20130506171943.GA22505@petertodd.org> References: <20130506161216.GA5193@petertodd.org> <20130506163732.GB5193@petertodd.org> <20130506171943.GA22505@petertodd.org> Date: Tue, 7 May 2013 11:00:52 +0200 X-Google-Sender-Auth: ey4yF3T4hh18igfHK6r4uY5U-zs Message-ID: From: Mike Hearn To: Peter Todd Content-Type: text/plain; charset=UTF-8 X-Spam-Score: -1.5 (-) 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 (mh.in.england[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 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: 1UZdla-00006H-AM Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Discovery/addr packets (was: Service bits for pruned nodes) 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: Tue, 07 May 2013 09:00:59 -0000 > You mean scam you with a zero-conf transaction that hasn't actually been > broadcast? Yeah. Or just scam you at all. It's hard to imagine an organisation as a big as a mobile carrier engaging in financial scamming (roaming fees excepted). I've said this before, but I think it's worth repeating. The double-spend protection the block chain gives you has a sweet spot where it's really, really valuable (essential even) and then there are lots of kinds of transactions on either side of that sweet spot that don't really benefit from it. Obvious/trivial case where you don't need a block chain - Facebook buys Instagram for a gajillion coins. The legal system is plenty good enough to ensure the payments are honoured. Another example, when my employer pays me my salary. They aren't going to double spend this except through some horrible accident that we can get sorted out some other way. Another case, very small payments. This is Satoshi's bag of crisps example. If the cost/complexity of double spending is higher than what the payment is worth, again, you don't really need the block chain. That's why it's worth optimising unconfirmed transactions to be harder to double spend, it optimises (pushes up) that lower bar. Place where you really want the chain - largeish sums of money are moving around, but not large enough to justify expensive cross-jurisdictional legal action, or where the cost of identity verification and all the associated paperwork is just too high. I guess most online transactions fall into this bucket today.