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-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1WipJJ-0003GE-4o for bitcoin-development@lists.sourceforge.net; Fri, 09 May 2014 18:14:17 +0000 Received-SPF: pass (sog-mx-3.v43.ch3.sourceforge.com: domain of petertodd.org designates 62.13.149.84 as permitted sender) client-ip=62.13.149.84; envelope-from=pete@petertodd.org; helo=outmail149084.authsmtp.net; Received: from outmail149084.authsmtp.net ([62.13.149.84]) by sog-mx-3.v43.ch3.sourceforge.com with esmtp (Exim 4.76) id 1WipJI-0003AK-20 for bitcoin-development@lists.sourceforge.net; Fri, 09 May 2014 18:14:17 +0000 Received: from mail-c235.authsmtp.com (mail-c235.authsmtp.com [62.13.128.235]) by punt18.authsmtp.com (8.14.2/8.14.2/) with ESMTP id s49IE8xC011863; Fri, 9 May 2014 19:14:08 +0100 (BST) Received: from savin (76-10-178-109.dsl.teksavvy.com [76.10.178.109]) (authenticated bits=128) by mail.authsmtp.com (8.14.2/8.14.2/) with ESMTP id s49IE57I096804 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Fri, 9 May 2014 19:14:07 +0100 (BST) Date: Fri, 9 May 2014 14:13:53 -0400 From: Peter Todd To: Pieter Wuille Message-ID: <20140509181353.GB27819@savin> References: <20140509150325.GA30436@savin> <20140509152715.GA12421@savin> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="i0/AhcQY5QxfSsSZ" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Server-Quench: b6812097-d7a5-11e3-b396-002590a15da7 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCd2Yg0TA1ZNQRgX IjsJECJaVQIpKltL GxAVKBZePFsRUQkR aQdMdgsUFVQNAgsB AmIbWl1eUVl7WWs7 bAxPbAVDY01GQQRq WVdMSlVNFUsrBRV4 cxsZKxl7cQ1GfDBx Y0ZqXj4JWkx7d0Z0 RVMAEjwDeGZhPWMC AkNRcR5UcAFPdx8U a1UrBXRDAzANdhES HhM4ODE3eDlSNilR RRkIIFQOdA4mNRIc DxEEVSkvEAUdTjQ2 Iho6YkYGG1oWOUI2 WQ84 X-Authentic-SMTP: 61633532353630.1023:706 X-AuthFastPath: 0 (Was 255) X-AuthSMTP-Origin: 76.10.178.109/587 X-AuthVirus-Status: No virus detected - but ensure you scan with your own anti-virus system. 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 SPF_PASS SPF: sender matches SPF record X-Headers-End: 1WipJI-0003AK-20 Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] ECDH in the payment protocol 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: Fri, 09 May 2014 18:14:17 -0000 --i0/AhcQY5QxfSsSZ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, May 09, 2014 at 05:50:33PM +0200, Pieter Wuille wrote: > I believe stealth addresses and the payment protocol both have their > use cases, and that they don't overlap. >=20 > If you do not want to communicate with the receiver, you typically do > not want them to know who is paying or for what (otherwise you're > already talking to them in some way, right?). That's perfect for > things like anonymous donations. >=20 > In pretty much every other case, communicating directly with the > receiver has benefits. Negotiation of the transaction details, > messages associated with the transaction, refund information, no need > to scan the blockchain for incoming transaction... and the ability to > cancel if either party doesn't agree. >=20 > Instead of adding stealth functionality to the payment protocol as a > last resort, I'd rather see the payment protocol improve its > atomicity. Either you want the data channel sender->receiver, or you > don't. If it isn't available and you want it, things should fail. If > you don't want it, you shouldn't try to use it in the first place. I don't think we're going to find that's practical unfortunately due to change. Every payment I make ties up txouts, so if we try to base the atomicity of payments on whether or not the payee decides to broadcast the transaction the payor is stuck with txouts that they can't use until the payee makes up their mind. That leads to lots and lots of nasty edge cases. OTOH if we base the atomicity of payment on whether or not a specific txout exists everything those edge cases don't exist. Yes, that might force us to expose transaction fees to the user, but after all it's the user who has control over those fees. A separate issue is IsStandard() rules, and a near-term project for me is to write a much relaxed version of them based on soft-fork safe whitelisting/blacklisting of opcodes, version numbers, mutability etc. We can definitely get to the point where those rules will change very little. --=20 'peter'[:-1]@petertodd.org 00000000000000006d5945d2dddece39487c36673e56a292b619b1929ff3b40f --i0/AhcQY5QxfSsSZ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (GNU/Linux) iQGrBAEBCACVBQJTbRrcXhSAAAAAABUAQGJsb2NraGFzaEBiaXRjb2luLm9yZzAw MDAwMDAwMDAwMDAwMDA3YzJkOGY3MTNlMmEzYzgwNGM2MjQ4Zjc4N2I2ZjU0ZDgw MjYzZjM0ZDU4MTg5MzAvFIAAAAAAFQARcGthLWFkZHJlc3NAZ251cGcub3JncGV0 ZUBwZXRlcnRvZC5vcmcACgkQJIFAPaXwkfvlMgf+LTYdD062VsC+5Po/aUoozSOc 2v89oEgtsZ2T2t0eg4ZB11IAaI+6wqfOVXkJK2/ipYUcTqL831Udgth6wm9Yxqnd fvde99jhY5dQFrRtAHBMbiQM+LZCDinARLxhI1KT6kGAFtQfxYWUml8Jqe1nyhq0 g4PqB6EypHrAfqAUTlr1F1qU83vvzXb+acrx+JvGFngMariRXTWxkfitRv++0+tC RVgQkwSLfxMhEBLum7FxGBE/GWtJ9xVbCPKRvmlnjSq+LSnyCvBTiATzOK9Z6eI9 C44OXjmNZj1/eMTVZufZNIsgycE2wiI+7Qb0WIoEjx5Ky9TV7nOnk0VqEaWXJA== =G5gP -----END PGP SIGNATURE----- --i0/AhcQY5QxfSsSZ--