Received: from sog-mx-3.v43.ch3.sourceforge.com ([172.29.43.193] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1YPa55-00061H-Ca for bitcoin-development@lists.sourceforge.net; Sun, 22 Feb 2015 17:12:35 +0000 Received-SPF: pass (sog-mx-3.v43.ch3.sourceforge.com: domain of petertodd.org designates 62.13.148.93 as permitted sender) client-ip=62.13.148.93; envelope-from=pete@petertodd.org; helo=outmail148093.authsmtp.net; Received: from outmail148093.authsmtp.net ([62.13.148.93]) by sog-mx-3.v43.ch3.sourceforge.com with esmtp (Exim 4.76) id 1YPa53-0003Br-IK for bitcoin-development@lists.sourceforge.net; Sun, 22 Feb 2015 17:12:35 +0000 Received: from mail-c237.authsmtp.com (mail-c237.authsmtp.com [62.13.128.237]) by punt16.authsmtp.com (8.14.2/8.14.2/) with ESMTP id t1MHCRxZ085558; Sun, 22 Feb 2015 17:12:27 GMT Received: from savin.petertodd.org (75-119-251-161.dsl.teksavvy.com [75.119.251.161]) (authenticated bits=128) by mail.authsmtp.com (8.14.2/8.14.2/) with ESMTP id t1MHCNvi097504 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Sun, 22 Feb 2015 17:12:25 GMT Date: Sun, 22 Feb 2015 12:12:22 -0500 From: Peter Todd To: Tom Harding Message-ID: <20150222171222.GA30816@savin.petertodd.org> References: <20150212064719.GA6563@savin.petertodd.org> <54EA0571.4050107@thinlink.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="BXVAT5kNtrzKuDFl" Content-Disposition: inline In-Reply-To: <54EA0571.4050107@thinlink.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Server-Quench: f9335106-bab5-11e4-9f74-002590a135d3 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCd2Yg0TA1ZNQRgX IjsJECJaVQIpKltL GxAVKBZePFsRUQkR aAdMdAAUHlAWAgsB AmMbWlNeUV97W2U7 bA9PbARUfEhLXhtr VklWR1pVCwQmRR18 fm1gFEByfgJDeHo+ ZERhWngVCk15dkN8 QkhJRzxUYHphaTUb TUkOcAdJcANIexZF O1F8UScOLwdSbGoL NQ4vNDcwO3BTJTpY RgYVKF8UXXNDBDMk QxkJEHAlDAgLSih7 MURgcwZaRFwabi0A X-Authentic-SMTP: 61633532353630.1024:706 X-AuthFastPath: 0 (Was 255) X-AuthSMTP-Origin: 75.119.251.161/587 X-AuthVirus-Status: No virus detected - but ensure you scan with your own anti-virus system. 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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 -0.0 AWL AWL: Adjusted score from AWL reputation of From: address X-Headers-End: 1YPa53-0003Br-IK Cc: bitcoin-development@lists.sourceforge.net Subject: Re: [Bitcoin-development] replace-by-fee v0.10.0rc4 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: Sun, 22 Feb 2015 17:12:35 -0000 --BXVAT5kNtrzKuDFl Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Feb 22, 2015 at 08:36:01AM -0800, Tom Harding wrote: > On 2/11/2015 10:47 PM, Peter Todd wrote: > >My replace-by-fee patch is now available for the v0.10.0rc4 release: > > > > https://github.com/petertodd/bitcoin/tree/replace-by-fee-v0.10.0rc4 > > >=20 > This patch immediately simplifies successful double-spends of > unconfirmed transactions. But the idea that it "gives a path to > making zeroconf transactions economically secure" is quite dubious. >=20 > * You don't provide sufficient means to detect and relay > double-spends, which is necessary to trigger a scorched-earth > reaction. Not all double-spends will conform to your replacement > rules. No, OTOH if they don't then the situation is no difference from what we have now, and replace-by-fee does no harm. Meanwhile, relaying of bare double-spend signatures can be implemented in the future, as I suggested last year for your/Andresen's double-spend relaying patch. Did you notice the even more obvious way to defeat ANYONECANPAY scorched earth with that patch? > * Maybe XT nodes would help to overcome this. But meanwhile, in > the ANYONECANPAY design, Bob's replacement is a triple-spend. Even > XT nodes won't relay it. So? RBF nodes will. > * It's unclear when, if ever, any senders/receivers will actually > try to use scorched-earth as a double-spend deterrent. I suspect many won't, because few people need to rely on unconfirmed transactions anyway. > Also, this patch significantly weakens DoS protections: >=20 > * It removes the early conflict check, making all conflict > processing more expensive If you're going to consider replacement, conflict processing will definitely be more expensive. :) An actual DoS attacker would do their DoS attack in a way where conflict processing has nothing to do with it, so this change does no actual harm. > * There is no attempt to protect against the same transaction > being continually replaced with the fee bumped by a minimal amount. What exact git commit were you looking at? I did have an early one that did have a bug along those lines, now fixed. The current version ensures every replacement pays at least as much additional fees as would normally cost to broadcast that much data on the network, and additionally requires the fees/KB to always increase; under all circumstances it should be no more of a DoS threat than low-fee transactions are otherwise. I'd like to know if there is a flaw in that code however! --=20 'peter'[:-1]@petertodd.org 000000000000000017c2f346f81e93956c538531682f5af3a95f9c94cb7a84e8 --BXVAT5kNtrzKuDFl Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- iQGrBAEBCACVBQJU6g3yXhSAAAAAABUAQGJsb2NraGFzaEBiaXRjb2luLm9yZzAw MDAwMDAwMDAwMDAwMDAxN2MyZjM0NmY4MWU5Mzk1NmM1Mzg1MzE2ODJmNWFmM2E5 NWY5Yzk0Y2I3YTg0ZTgvFIAAAAAAFQARcGthLWFkZHJlc3NAZ251cGcub3JncGV0 ZUBwZXRlcnRvZC5vcmcACgkQJIFAPaXwkfuYGgf/ZlcDZx7LmSQ99Oz+K7EHEKQL OxLcgvZc+Ondnf0FYgO02oYyQi1XMpoZ6tV1gre12EeDKpafXI5hTpb/78/puZS3 4HabFxMXgz/0PKSj171Ew95EoEpp8jAG/xJwpnL/pdXmbFLrcZ3n+Of6dExn+QLV DQs5kax5bhFkZ04QKFhYlW229OiKZoprEKTWdjSEPVSutkHChNC2jy2QHOBQoxoW ANEy4762JRTbUFVw3KXNgIy5aeF7xlL2HHKIwsSrmpZTJSa4zeIt0FTH2ZyUflib g/+NZ9q1LrH3fQtqAP9c8L7ovrFIK9DrPkVYtThFhnFv7H07wup2dfRrHSMOYg== =kerc -----END PGP SIGNATURE----- --BXVAT5kNtrzKuDFl--