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-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1VzBXA-0007MJ-Ug for bitcoin-development@lists.sourceforge.net; Fri, 03 Jan 2014 20:39:56 +0000 Received-SPF: pass (sog-mx-1.v43.ch3.sourceforge.com: domain of petertodd.org designates 62.13.149.55 as permitted sender) client-ip=62.13.149.55; envelope-from=pete@petertodd.org; helo=outmail149055.authsmtp.co.uk; Received: from outmail149055.authsmtp.co.uk ([62.13.149.55]) by sog-mx-1.v43.ch3.sourceforge.com with esmtp (Exim 4.76) id 1VzBX9-0001Ha-GO for bitcoin-development@lists.sourceforge.net; Fri, 03 Jan 2014 20:39:56 +0000 Received: from mail-c237.authsmtp.com (mail-c237.authsmtp.com [62.13.128.237]) by punt17.authsmtp.com (8.14.2/8.14.2/) with ESMTP id s03KdjxR051444; Fri, 3 Jan 2014 20:39:45 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 s03KdeoF056382 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Fri, 3 Jan 2014 20:39:42 GMT Date: Fri, 3 Jan 2014 15:39:39 -0500 From: Peter Todd To: Adam Back Message-ID: <20140103203939.GA30273@savin> References: <20140103202320.GA16515@netbook.cypherspace.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="5vNYLRcllDrimb99" Content-Disposition: inline In-Reply-To: <20140103202320.GA16515@netbook.cypherspace.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-Server-Quench: 2cff2b8d-74b7-11e3-94fa-002590a135d3 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCd2Yg0TA1ZNQRgX IjsJECJaVQIpKltL GxAVKBZePFsRUQkR aQdMdgEUElQaAgsB AmIbWVReU1R7XWA7 bAxPbAVDY01GQQRq WVdMSlVNFUsrAR96 UktBJBl3cQZOejBx Y0FlXD5ZDxIsdxR1 FlNTET8BeGZhPWMC WUQOJh5UcAFPdx8U a1N6AHBDAzANdhES HhM4ODE3eDlSNilR RRkIIFQOdA4iGHY9 Sx0LVTsoBwUMQzk+ NRovNl8CEQ4JO1Q3 PF09EUkTMxIXB2UA X-Authentic-SMTP: 61633532353630.1024:706 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: 1VzBX9-0001Ha-GO Cc: bitcoin-development Subject: Re: [Bitcoin-development] An idea for alternative payment scheme 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, 03 Jan 2014 20:39:57 -0000 --5vNYLRcllDrimb99 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Jan 03, 2014 at 09:23:20PM +0100, Adam Back wrote: > Seems like you (Nadav) are the third person to reinvent this idea so far = :) Lol, fourth if you include me, although my case is rather embarassing as I had re-read Bytecoin's original post recently and completely missed the main point of it! > I wrote up some of the post-Bytecoin variants here: >=20 > https://bitcointalk.org/index.php?topic=3D317835.msg4103530#msg4103530 >=20 > The general limitation so far is its not SPV compatible, so the recipient > has to test each payment to see if its one he can compute the private key > for. Or the sender has to send the recipient out of band the derivation > key. Actually I think it has the potential to be *more* SPV compatible than the alternative, as in conjunction with prefix filters it lets you receive unlimited unrelated payments that you can find in the blockchain with a single prefix query with a fixed bandwidth/anonymity set size tradeoff. (obviously in conjunction with one of the many ways of tagging transactions for more efficient search) The BIP38 approach with UI's that make it easy to create a new address for every payment on the other hand force you to either accept higher bandwidth consumption, or decrease your anonymity set size, or lose payments. (inclusive) I've got a post talking about this in more detail as well as an overview of bloom filters vs. prefix filters that I'll publish tomorrow. (tl;dr: bloom filters have very poor O(n^2) scalability and should be depreciated) > However at present most of the bitcoin infrastructure is using the bitcoin > broadcast channel as the communication channel, which also supports payer > and payee not being simultaneously online. You have to be careful also n= ot > to lose the key. You dont want a subsequent payer data loss event to lose > money for the recipient. You want the message to be sent atomically. >=20 > It does seem like a very attractive proposition to be able to fix the > address reuse issue. Admonishment to not reuse addresses doesnt seem to > have been successful so far, and there are multiple widely used wallets t= hat > reuse addresses (probably in part because they didnt implement HD wallets > and so are scared of losing addresses due to backup failure risks of non = HD > wallets and fresh addresses). --=20 'peter'[:-1]@petertodd.org 0000000000000001a96469654430aa06e4ae7c7328a7eb848c6fc63443f24e4a --5vNYLRcllDrimb99 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQGrBAEBCACVBQJSxyALXhSAAAAAABUAQGJsb2NraGFzaEBiaXRjb2luLm9yZzAw MDAwMDAwMDAwMDAwMDMwNjVmMzJkYTI2ZGUxZGVkYTkzZWI3MjJiZjFkYzRhMWI3 ODdlN2Q2OGQyODJkYmMvFIAAAAAAFQARcGthLWFkZHJlc3NAZ251cGcub3JncGV0 ZUBwZXRlcnRvZC5vcmcACgkQJIFAPaXwkfvbAwgAshgdy9cKqvFyUybeJ9uG2ILX IFnCWPTHsgj0wpD9Za7MHqCYTZQTqLGS+9If0OGtDPnk3pkBI+fUndK70zZbKNRn ILjUwFa1klofRs/mfcAaUqTDo6O31AbknoQt8dTBxoEZHqVrIwgbPMH/uIie6Vmc ueYNLclH0jKsp2z9ihirpfvgX9zEqYR9Tu2fWogq7MocgXvN93zSXiodt0n7jzrd Zmm4ZMrX+fwQ1mCYlPrrIe3m+g1sGOOt5Vkg73ZmICDKAU2RwlDuwH6eoWVTYOI0 w7GhRQZ6zuEDXeIiVm5bF9I8RrFDgg9fLqE9WyzE+AGSHEK1zQ6fGWb1XT/YkA== =85xT -----END PGP SIGNATURE----- --5vNYLRcllDrimb99--