Received: from sog-mx-1.v43.ch3.sourceforge.com ([172.29.43.191] helo=mx.sourceforge.net) by sfs-ml-1.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1UPlJd-000741-7q for bitcoin-development@lists.sourceforge.net; Wed, 10 Apr 2013 03:03:17 +0000 Received-SPF: pass (sog-mx-1.v43.ch3.sourceforge.com: domain of petertodd.org designates 62.13.148.113 as permitted sender) client-ip=62.13.148.113; envelope-from=pete@petertodd.org; helo=outmail148113.authsmtp.com; Received: from outmail148113.authsmtp.com ([62.13.148.113]) by sog-mx-1.v43.ch3.sourceforge.com with esmtp (Exim 4.76) id 1UPlJb-0006mi-Gp for bitcoin-development@lists.sourceforge.net; Wed, 10 Apr 2013 03:03:17 +0000 Received: from mail-c233.authsmtp.com (mail-c233.authsmtp.com [62.13.128.233]) by punt10.authsmtp.com (8.14.2/8.14.2/Kp) with ESMTP id r3A336HC041129; Wed, 10 Apr 2013 04:03:06 +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 r3A331WP085169 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Wed, 10 Apr 2013 04:03:04 +0100 (BST) Date: Tue, 9 Apr 2013 23:03:01 -0400 From: Peter Todd To: Gregory Maxwell Message-ID: <20130410030301.GA9921@savin> References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="9jxsPFA5p3P2qPhR" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Server-Quench: 29e2167d-a18b-11e2-a49c-0025907707a1 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCd2Yg0TA1ZNQRgX IjsJECJaVQIpKltL GxAVKBZePFsRUQkR aAdMdwIUGUUGAgsB AmUbW1BeUF57WWc7 bAxPbAVDY01GQQRq WVdMSlVNFUsqAm0C BR95Mhl6cgRAcTBx ZU9gWD5ZVRF4dEB6 FlMFFGVUeGZhPWIC AURRJB5UcAFPdx9C bVB4BXJDAzANdhES HhM4ODE3eDlSNilR RRkIIFQOdA43GXZp EA0eE3B/SnRSXz8+ eElEYgtLAVofdxVl CAw/VFQEBBYIAAxC BUhXERhVLkUIcDE3 ChlTUkMpETtqXTdb HwEzFUgdSmkFRzZW QRsSYUZTDAh4B3wA dDZQMGUQCEQoIks2 P2wkNgUsBxw5TXIA X-Authentic-SMTP: 61633532353630.1021:706 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: 1UPlJb-0006mi-Gp 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 03:03:17 -0000 --9jxsPFA5p3P2qPhR Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Apr 09, 2013 at 07:53:38PM -0700, Gregory Maxwell wrote: 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. 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. > (1) Define a new address type, P2SH^2 like P2SH but is instead > H(H(ScriptPubKey)) instead of H(ScriptPubKey). A P2SH^2 address it is > a hash of a P2SH address. >=20 > (2) Make a relay rule so that to relay a P2SH^2 you must include > along the inner P2SH address. All nodes can trivially verify it by > hashing it. >=20 > (2a) If we find that miners mine P2SH^2 addresses where the P2SH > wasn't relayed (e.g. they want the fees) we introduce a block > discouragement rule where a block is discouraged if you receive it > without receiving the P2SH^2 pre-images for it. >=20 > With this minor change there is _no_ non-prunable location for users > to cram data into except values. (and the inefficiency of cramming > data into values is a strong deterrent in any case) >=20 > The same thing could also be done for OP_RETURN PUSH value outputs > used to link transactions to data. Make the data be a hash, outside of > the txn include the preimage of the hash. >=20 > -------------------------------------------------------------------------= ----- > Precog is a next-generation analytics platform capable of advanced > analytics on semi-structured data. The platform includes APIs for building > apps and a phenomenal toolset for data science. Developers can use > our toolset for easy data analysis & visualization. Get a free account! > http://www2.precog.com/precogplatform/slashdotnewsletter > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development >=20 --=20 'peter'[:-1]@petertodd.org --9jxsPFA5p3P2qPhR Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQEcBAEBAgAGBQJRZNZkAAoJEH+rEUJn5PoEPn8H/RD9nPfRNRLTzom8oXxO/sR5 lDsz50flKofZVR9JT6MS7vBa9P62/31kqBr1i2XbXSZw23OuG57Ws8XvBTjNMb09 FLtxYd+25M3b02uiDAAI85imPHzFkj7W92gOG/11IflxKERR9m/mhDobt1+5XGVk 7LS3Da1r8eRcbOZV6/MZuq1uTJvBCPSR5SXNiZHgVPmiR6EaKWnK0fmEgU3RqcjG l4cH6d9HOw8tLXl09ctsokkpA1pOmrXxBnVA1gXlXVAIK+xkaZDri+itJGp2BpmQ JM+miYf/jq7JphCpV8XIYqzFAYqGqlhFLuVVbctSXNvtxk38d7uk5FZBHg3wUVA= =N92b -----END PGP SIGNATURE----- --9jxsPFA5p3P2qPhR--