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-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1UPlOv-0001ro-LQ for bitcoin-development@lists.sourceforge.net; Wed, 10 Apr 2013 03:08:45 +0000 Received-SPF: pass (sog-mx-3.v43.ch3.sourceforge.com: domain of petertodd.org designates 62.13.148.154 as permitted sender) client-ip=62.13.148.154; envelope-from=pete@petertodd.org; helo=outmail148154.authsmtp.co.uk; Received: from outmail148154.authsmtp.co.uk ([62.13.148.154]) by sog-mx-3.v43.ch3.sourceforge.com with esmtp (Exim 4.76) id 1UPlOs-0008SH-Sk for bitcoin-development@lists.sourceforge.net; Wed, 10 Apr 2013 03:08:45 +0000 Received: from mail-c235.authsmtp.com (mail-c235.authsmtp.com [62.13.128.235]) by punt6.authsmtp.com (8.14.2/8.14.2/Kp) with ESMTP id r3A38ZgJ007052; Wed, 10 Apr 2013 04:08:35 +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 r3A38VUr045584 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Wed, 10 Apr 2013 04:08:33 +0100 (BST) Date: Tue, 9 Apr 2013 23:08:31 -0400 From: Peter Todd To: Gregory Maxwell Message-ID: <20130410030831.GA12447@savin> References: <20130410030301.GA9921@savin> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="CE+1k2dSO48ffgeK" Content-Disposition: inline In-Reply-To: <20130410030301.GA9921@savin> User-Agent: Mutt/1.5.21 (2010-09-15) X-Server-Quench: ee2244bd-a18b-11e2-b5c5-002590a15da7 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCd2Yg0TA1ZNQRgX IjsJECJaVQIpKltL GxAVKBZePFsRUQkR aAdMdwIUGUUGAgsB AmUbW1BeUFV7Wmc7 bAxPbAVDY01GQQRq WVdMSlVNFUsqAm0C Dnh7EBl2cgBOfDB4 ZUdiECUOXkZ+cRQp Xx9VHT8bZGY1an1N VRNdagNUcgZDfk5E bwQuUz1vNG8XDQg5 AwQ0PjZ0MThBJSBS WgQAK04nCXoMVmtr WgwMWGV4JBodXShk en5ufwkBAEhUYhIL ZkUsX04vOgUYCxFE FltcNyNQO1A2XDYs FwpVUHkfFgpBUSBB HgYfdUoAV2tPRiQd VBxvHE0IIB4SBWF0 SDs/GhApEFksLl4n eh8YNRwtGho4IwAA 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: 1UPlOs-0008SH-Sk Cc: Bitcoin Development Subject: Re: [Bitcoin-development] =?utf-8?q?To_prevent_arbitrary_data_storage?= =?utf-8?q?_in_txouts_=E2=80=94_The_Ultimate_Solution?= 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, 10 Apr 2013 03:08:45 -0000 --CE+1k2dSO48ffgeK Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Apr 09, 2013 at 11:03:01PM -0400, Peter Todd wrote: > On Tue, Apr 09, 2013 at 07:53:38PM -0700, Gregory Maxwell wrote: >=20 > Note how we can already do this: P2SH uses Hash160, which is > RIPE160(SHA256(d)) We still need a new P2SH *address* type, that > provides the full 256 bits, but no-one uses P2SH addresses yet anyway. >=20 > This will restrict data stuffing to brute forcing hash collisions. It'd > be interesting working out the math for how effective that is, but it'll > certainely be expensive in terms of time hashing power that could solve > shares instead. Oh, and while we're at it, long-term (hard-fork) it'd be good to change the tx hash algorithm to extend the merkle tree into the txouts/txins itself, which means that to prove a given txout exists you only need to provide it, rather than the full tx. Currently pruning can't prune a whole tx until every output is spent. Make that change and we can prune tx's bit by bit, and still be able to serve nodes requesting proof of their UTXO without making life difficult for anyone trying to spent old UTXO's. The idea is also part of UTXO proof stuff anyway. --=20 'peter'[:-1]@petertodd.org --CE+1k2dSO48ffgeK Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQEcBAEBAgAGBQJRZNeuAAoJEH+rEUJn5PoEFQgH/iPyua/jhkBu/e1koU6/rw9O qcPsKDMHvnTglfcI+L9TQJK1YGdRDcG/Nh2Q3f7ZeTPc/DYawVJ8cJiNjj1tbrd9 xLcUmdYSKW9OY2y9C2GqqontDXhF/41usGhOKDU+TdlyVvNICbJ2dfFpB5A4qFJb uPAkycMRDmrd7GnaP5wd8B5UEfO6cRldvR4kbe6ioosgXt1Br+FMe8v2kB4YWYZx yOtyrVToZkxG1j4mwTDL4gRkhVLc1mbf2imXWo5xpBw0ZZXoWthkeS70DBTgTQI8 XGotBytqZ4CaYTtFhnB75Ro8oYNjLdxwMZVIx7HozrPOAsBQ32L4dKpTi1q59NA= =2K0w -----END PGP SIGNATURE----- --CE+1k2dSO48ffgeK--