From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1UirVr-0004hl-3O for bitcoin-development@lists.sourceforge.net; Sat, 01 Jun 2013 19:30:51 +0000 Received-SPF: pass (sog-mx-2.v43.ch3.sourceforge.com: domain of petertodd.org designates 62.13.149.77 as permitted sender) client-ip=62.13.149.77; envelope-from=pete@petertodd.org; helo=outmail149077.authsmtp.com; Received: from outmail149077.authsmtp.com ([62.13.149.77]) by sog-mx-2.v43.ch3.sourceforge.com with esmtp (Exim 4.76) id 1UirVp-0005mv-68 for bitcoin-development@lists.sourceforge.net; Sat, 01 Jun 2013 19:30:51 +0000 Received: from mail-c226.authsmtp.com (mail-c226.authsmtp.com [62.13.128.226]) by punt7.authsmtp.com (8.14.2/8.14.2/Kp) with ESMTP id r51JUhcH032870 for ; Sat, 1 Jun 2013 20:30:43 +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 r51JUaCI094160 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO) for ; Sat, 1 Jun 2013 20:30:39 +0100 (BST) Date: Sat, 1 Jun 2013 15:30:36 -0400 From: Peter Todd To: bitcoin-development@lists.sourceforge.net Message-ID: <20130601193036.GA13873@savin> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="PNTmBPCT7hxwcZjr" Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-Server-Quench: bdd3b9be-caf1-11e2-98a9-0025907ec6c5 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCd2Yg0TA1ZNQRgX IjsJECJaVQIpKltL GxAVJwpGK10IU0Fd P1hXKl1LNVAaWXld WiVPGEoXDxgzCjYj NEgGOBsDNw4AXwR1 Kg0XXVBSFQZ4AxwL BR4UURA8cANYeX5u ZEFqQHFbVVt/fUFi QwAWEGx8ADYTEWAW VEFed01ReABIME0R PlMtXSFYfDZWMHt9 RlY+ZXVgbTwObXwN GFxcdQ0fShgAQygE XRcaGi4mGR9NXCI9 M1koLUQfVFoWekA7 MlZpUFQJNBkfTwZX GQRWGCJfKxEGWjYz EB9BFVMYCyVQRytV CBklahFPGF4aA3IA TEFBTBoMEEsA X-Authentic-SMTP: 61633532353630.1020:706 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: 1UirVp-0005mv-68 Subject: [Bitcoin-development] Proposal: soft-fork to make anyone-can-spend outputs unspendable for 100 blocks 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: Sat, 01 Jun 2013 19:30:51 -0000 --PNTmBPCT7hxwcZjr Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Currently the most compact way (proof-size) to sacrifice Bitcoins that does not involve making them unspendable is to create a anyone-can-spend output as the last txout in the coinbase of a block: scriptPubKey: OP_TRUE The proof is then the SHA256 midstate, the txout, and the merkle path to the block header. However this mechanism needs miner support, and it is not possible to pay for such a sacrifice securely, or create an assurance contract to create one. A anyone-can-spend in a regular txout is another option, but there is no way to prevent a miner from including a transaction spending that txout in the same block. Once that happens, there is no way to prove the miner didn't create both, thus invalidating the sacrifice. The announce-commit protocol solves that problem, but at the cost of a much larger proof, especially if multiple parties want to get together to pay the cost of the sacrifice. (the proof must include the entire tx used to make the sacrifice) However if we add a rule where txouts ending in OP_TRUE are unspendable for 100 blocks, similar to coinbases, we fix these problems. The rule can be done as a soft-fork with 95% support in the same way the blockheight rule was implemented. Along with that change anyone-can-spend outputs should be make IsStandard() so they will be relayed. The alternative is sacrifices to unspendable outputs, which is very undesirable compared to sending the money to miners to further strengthen the security of the network. We should always make it easy for people to write code that does what is best for Bitcoin. --=20 'peter'[:-1]@petertodd.org 00000000000000ce3427502ee6a254fed27e1cd21a656a335cd2ada79b7b5293 --PNTmBPCT7hxwcZjr Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQEcBAEBCAAGBQJRqkvbAAoJECSBQD2l8JH7YFcH/0AaUxfThHW46BTYFjCEgmzH 8+q7EqQFePWQc6IdcQ4WvN3d9OC8/KQ07fKx7ll2YtFiBakneJwEkJNCaGgO04zn 9oflgenHmbXpwAPWzw6r3GZwHW7WOUS+yn4XcWQbsOxPBgWM8JnI0TtB3jdpfE7/ OYwxFhqau7hOugAhjJEQFUkNzqFyxzjQHqxozEvQ+T4Hum/KdGD/VFZ2aYFPXzI4 8fV0y5JqV6ruVwlcblmAaYQWDTRe2HWQJaLqVKTjDkWy8AxU0vZAFH97pdpJJjT6 0ZoyG/RqJDN9bolMmLMgmQDzqVqHG86NJ3umx7NCOVKwDexf0MZWe4YzsdhA1XU= =MhoJ -----END PGP SIGNATURE----- --PNTmBPCT7hxwcZjr--