From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-1.v43.ch3.sourceforge.com ([172.29.43.191] helo=mx.sourceforge.net) by sfs-ml-1.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1R8eC1-0000S9-Ff for bitcoin-development@lists.sourceforge.net; Tue, 27 Sep 2011 20:23:53 +0000 Received-SPF: pass (sog-mx-1.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.216.182 as permitted sender) client-ip=209.85.216.182; envelope-from=gmaxwell@gmail.com; helo=mail-qy0-f182.google.com; Received: from mail-qy0-f182.google.com ([209.85.216.182]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1R8eC0-0002cf-Lr for bitcoin-development@lists.sourceforge.net; Tue, 27 Sep 2011 20:23:53 +0000 Received: by qyk4 with SMTP id 4so8692700qyk.13 for ; Tue, 27 Sep 2011 13:23:47 -0700 (PDT) MIME-Version: 1.0 Received: by 10.224.217.66 with SMTP id hl2mr6621093qab.246.1317155027191; Tue, 27 Sep 2011 13:23:47 -0700 (PDT) Received: by 10.229.222.18 with HTTP; Tue, 27 Sep 2011 13:23:47 -0700 (PDT) In-Reply-To: <201109271608.07053.luke@dashjr.org> References: <201109261517.11245.luke@dashjr.org> <201109271608.07053.luke@dashjr.org> Date: Tue, 27 Sep 2011 16:23:47 -0400 Message-ID: From: Gregory Maxwell To: Luke-Jr Content-Type: text/plain; charset=UTF-8 X-Spam-Score: -1.3 (-) 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 0.3 AWL AWL: From: address is in the auto white-list X-Headers-End: 1R8eC0-0002cf-Lr Cc: bitcoin-development@lists.sourceforge.net Subject: Re: [Bitcoin-development] Newly introduced DoS 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, 27 Sep 2011 20:23:53 -0000 On Tue, Sep 27, 2011 at 4:08 PM, Luke-Jr wrote: > Is it certain that it cannot be triggered by a peer having some huge number > more blocks than you? Might be better to have a global flag that indicates when the node thinks its current with the network (this could have other UI impacts, like letting the user know if they send and their connectivity looks non-current), and only enforce this check when the node believes that its current. Currency could be =height>last_checkpoint&&top_timestamp>now()-safe_amount; with safe_amount to be high enough that it's very unlikely to be falsely triggered by an improbably long gap.