From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-4.v43.ch3.sourceforge.com ([172.29.43.194] helo=mx.sourceforge.net) by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1Ucags-0002iH-RB for bitcoin-development@lists.sourceforge.net; Wed, 15 May 2013 12:20:18 +0000 Received-SPF: pass (sog-mx-4.v43.ch3.sourceforge.com: domain of petertodd.org designates 62.13.149.75 as permitted sender) client-ip=62.13.149.75; envelope-from=pete@petertodd.org; helo=outmail149075.authsmtp.net; Received: from outmail149075.authsmtp.net ([62.13.149.75]) by sog-mx-4.v43.ch3.sourceforge.com with esmtp (Exim 4.76) id 1Ucagd-0007rh-H9 for bitcoin-development@lists.sourceforge.net; Wed, 15 May 2013 12:20:18 +0000 Received: from mail-c232.authsmtp.com (mail-c232.authsmtp.com [62.13.128.232]) by punt14.authsmtp.com (8.14.2/8.14.2/) with ESMTP id r4FCJvT4042833 for ; Wed, 15 May 2013 12:19:57 GMT 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 r4FCJpfT066368 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO) for ; Wed, 15 May 2013 13:19:53 +0100 (BST) Date: Wed, 15 May 2013 08:19:50 -0400 From: Peter Todd To: Bitcoin-Dev Message-ID: <20130515121950.GC26020@savin> References: <20130515113827.GB26020@savin> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="adJ1OR3c6QgCpb/j" Content-Disposition: inline In-Reply-To: <20130515113827.GB26020@savin> User-Agent: Mutt/1.5.21 (2010-09-15) X-Server-Quench: bfd34131-bd59-11e2-b10b-0025903375e2 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCd2Yg0TA1ZNQRgX IjsJECJaVQIpKltL GxAVJwpGK10IU0Fd P1hXKl1LNVAaWXld WiVPGEoXDxgzCjYj NEgGOBsDNw4AXgB1 LRkAXVBSFQZ4AB8L BxcUVx08cANYeX5u ZEFqQHFbVVt/fUFi QwAWERt1Hyc2DGAZ VkNef01QdgVOME0T PlN7VXAMfDdTY3N9 RlY+ZXU7ZG1VbXwN GFxcdQlJHhsGRCgG SkJKLh8uAUYCRiN2 IxE4J1obBEMcNFkH eQELZXlQKRINAxdS V09KGmdcLloAQSVj FRldV0cUGTlcWjtd CX9gLhhVCDhfHzFA CU1JShcAQz1EWWFD TzBTViwmEFkvKAo2 KC0ZKgg6Bxw5TQEF ABQJVyMQ X-Authentic-SMTP: 61633532353630.1019:706 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 0.0 TIME_LIMIT_EXCEEDED Exceeded time limit / deadline X-Headers-End: 1Ucagd-0007rh-H9 Subject: Re: [Bitcoin-development] 2BTC reward for making probabalistic double-spending via conflicting transactions easy 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: Wed, 15 May 2013 12:20:19 -0000 --adJ1OR3c6QgCpb/j Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, May 15, 2013 at 07:38:27AM -0400, Peter Todd wrote: > So I'm offering 2BTC for anyone who comes up with a nice and easy to use > command line tool that lets you automagically create one version of the > transaction sending the coins to the desired recipient, and another > version sending all the coins back to you, both with the same > transaction inputs. In addition to creating the two versions, you need > to find a way to broadcast them both simultaneously to different nodes > on the network. One clever approach might be to use blockchain.info's > raw transaction POST API, and your local Bitcoin node. Oh, and while we're at it, a good starting point for your work would be Gavin's spendfrom utility in the contrib/spendfrom directory in the Bitcoin-QT respository. Also please do keep in mind that it's much better for the community if an attack is demonstrated first, followed by releasing the code some time later. --=20 'peter'[:-1]@petertodd.org --adJ1OR3c6QgCpb/j Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQEcBAEBCAAGBQJRk31mAAoJECSBQD2l8JH7opkIAIJc8Gg9F5wXZup0eTmIsFKj 0dAApIrXIx5BCEOTg5bUR2ds5Ux6Gi0KPs9BBxi36FrEMMvl/kF4ce1ovgvQ3eZl HHpqMcIRIjeHVoexp1i/gPQdRmrtcDo+FA5/v6XzkJMUgSxqF7smECLssdAR/2ds X8SosCV4JvbxdpPHbbu3RsKduD2vAbcJ9bPeMafF+C1CVKWNMrbSDkSFfuoT4LCW +uQ/6urkX28b3eLjhi+rkJ1IMpBGnTIY/O0Re5qxbBGZq8i0EKzHak6akb0imHKQ /Ikv6yoNgCqLyjxWSRKjSr69RqNeXfEVIdgxfQEPCKfTKbH+1dxu+P3nFo8VPFw= =Yan0 -----END PGP SIGNATURE----- --adJ1OR3c6QgCpb/j--