Received: from sog-mx-4.v43.ch3.sourceforge.com ([172.29.43.194] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1W2paB-0005Vb-MQ for bitcoin-development@lists.sourceforge.net; Mon, 13 Jan 2014 22:02:07 +0000 Received-SPF: pass (sog-mx-4.v43.ch3.sourceforge.com: domain of taplink.co designates 50.117.27.232 as permitted sender) client-ip=50.117.27.232; envelope-from=jeremy@taplink.co; helo=mail.taplink.co; Received: from mail.taplink.co ([50.117.27.232]) by sog-mx-4.v43.ch3.sourceforge.com with smtp (Exim 4.76) id 1W2paA-0006MV-Vo for bitcoin-development@lists.sourceforge.net; Mon, 13 Jan 2014 22:02:07 +0000 Received: from [192.168.1.134] ([76.21.80.109]) by mail.taplink.co ; Mon, 13 Jan 2014 14:10:26 -0800 References: <20140106120338.GA14918@savin> <20140110102037.GB25749@savin> <20140113194049.GJ38964@giles.gnomon.org.uk> <52D4458C.6010909@gmail.com> Mime-Version: 1.0 (1.0) In-Reply-To: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Message-Id: <19AE1549-16E0-4119-8BE9-8F4DFD3381C1@taplink.co> X-Mailer: iPhone Mail (10B146) From: Jeremy Spilman Date: Mon, 13 Jan 2014 14:02:00 -0800 To: Gregory Maxwell oclient: 76.21.80.109#jeremy@taplink.co#465 X-Spam-Score: -1.7 (-) 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 SPF_PASS SPF: sender matches SPF record -0.1 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -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: 1W2paA-0006MV-Vo Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Stealth Addresses 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: Mon, 13 Jan 2014 22:02:07 -0000 > Uh while I'm responding again, what I'd discussed with Peter Todd in > IRC used two EC points in the stealth address. One for the payment and > one for the ECDH. The reason to use two is that it makes delegating > detection possible and so you don't have to have you spending keys > online to even detect these payments. Why'd that get dropped? I think this is exactly what I've implemented. I decided to put both pubKeys in a 2-of-2 multisig, instead of keeping one o= f the pubKeys in the OP-RETURN, to prevent a malicious sender from triggerin= g false positives on your online detection key when the funds are actually s= till fully controlled by the payer. You can still have a false positive (only 1 of 2 keys actually yours) but th= e funds would be trapped so it's unlikely anyone would do it.=20 Can you take a look at the Gist and TXs on TestNet I sent out, and see if th= at's in line with what you expected? I would also greatly appreciate if you could review the discussion around do= ing two ECDH operations with a single ephemeral key. Thanks! --Jeremy