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-1.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1YbEcI-00056s-Gq for bitcoin-development@lists.sourceforge.net; Thu, 26 Mar 2015 20:43:02 +0000 Received-SPF: pass (sog-mx-3.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.213.182 as permitted sender) client-ip=209.85.213.182; envelope-from=gmaxwell@gmail.com; helo=mail-ig0-f182.google.com; Received: from mail-ig0-f182.google.com ([209.85.213.182]) by sog-mx-3.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1YbEcH-00067O-JH for bitcoin-development@lists.sourceforge.net; Thu, 26 Mar 2015 20:43:02 +0000 Received: by igbud6 with SMTP id ud6so3098300igb.1 for ; Thu, 26 Mar 2015 13:42:55 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.42.41.148 with SMTP id p20mr40146704ice.62.1427402575818; Thu, 26 Mar 2015 13:42:55 -0700 (PDT) Received: by 10.107.6.133 with HTTP; Thu, 26 Mar 2015 13:42:55 -0700 (PDT) In-Reply-To: <55146E2C.9020105@thinlink.com> References: <55121611.1030104@thinlink.com> <551301F0.9020806@thinlink.com> <55146E2C.9020105@thinlink.com> Date: Thu, 26 Mar 2015 20:42:55 +0000 Message-ID: From: Gregory Maxwell To: Tom Harding 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 (gmaxwell[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: 1YbEcH-00067O-JH Cc: Bitcoin Development Subject: Re: [Bitcoin-development] Address Expiration to Prevent Reuse 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: Thu, 26 Mar 2015 20:43:02 -0000 On Thu, Mar 26, 2015 at 8:38 PM, Tom Harding wrote: > I addressed that by limiting the duplicate check to an X-block segment. X > is hard-coded in this simple scheme (X=144 => "1-day addresses"). You > could picture a selectable expiration duration too. If its to be heuristic in any case why not make it a client feature instead of a consensus rule? If someone wants to bypass anything they always can, thats what I mean by "hide their payment under a rock" E.g. I can take your pubkey, add G to it (adding 1 to the private key), strip off the time limits, and send the funds. "What do you mean I didn't pay you? I wrote a check. locked it in a safe, and burred it in your back garden." The answer to this can only be that payment is only tendered when its made _exactly_ to the payee's specifications. If someone violates the specifications all they're doing is destroying coins. Nothing can stop people from destroying coins... Which is why a simpler, safer, client enforced behavior is probably preferable. Someone who wants to go hack their client to make a payment that isn't according to the payee will have to live with the results, esp. as we can't prevent that in a strong sense.