Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 565EA1BB for ; Mon, 2 Oct 2017 02:57:29 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from zinan.dashjr.org (zinan.dashjr.org [192.3.11.21]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id ED653151 for ; Mon, 2 Oct 2017 02:57:28 +0000 (UTC) Received: from ishibashi.localnet (unknown [IPv6:2001:470:5:265:a45d:823b:2d27:961c]) (Authenticated sender: luke-jr) by zinan.dashjr.org (Postfix) with ESMTPSA id DB14638A0077; Mon, 2 Oct 2017 02:56:32 +0000 (UTC) X-Hashcash: 1:25:171002:mark@friedenbach.org::5c5+8eeKM5VmdPJI:a1K/0 X-Hashcash: 1:25:171002:jl2012@xbt.hk::2vF/yQJjqdzlspAJ:KNMF X-Hashcash: 1:25:171002:bitcoin-dev@lists.linuxfoundation.org::cAygigUfL3hb+130:c3G7h X-Hashcash: 1:25:171002:roconnor@blockstream.io::tssMEFpW/NgrCDeW:15FD From: Luke Dashjr To: Mark Friedenbach Date: Mon, 2 Oct 2017 02:56:27 +0000 User-Agent: KMail/1.13.7 (Linux/4.12.5-gentoo; KDE/4.14.34; x86_64; ; ) References: <201710010113.30518.luke@dashjr.org> <30B31B43-B603-4793-BDFB-B7E25FD96D1B@xbt.hk> <50CA8523-3D1A-409E-9B7D-51EA5FC4B898@friedenbach.org> In-Reply-To: <50CA8523-3D1A-409E-9B7D-51EA5FC4B898@friedenbach.org> X-PGP-Key-Fingerprint: E463 A93F 5F31 17EE DE6C 7316 BD02 9424 21F4 889F X-PGP-Key-ID: BD02942421F4889F X-PGP-Keyserver: hkp://pgp.mit.edu MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <201710020256.27964.luke@dashjr.org> X-Spam-Status: No, score=-2.3 required=5.0 tests=RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD autolearn=disabled version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Cc: bitcoin-dev Subject: Re: [bitcoin-dev] Version 1 witness programs (first draft) X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 02 Oct 2017 02:57:29 -0000 On Monday 02 October 2017 12:35:38 AM Mark Friedenbach wrote: > > b. OP_RETURNTRUE (Luke). I proposed this in an earlier version of BIP114 > > but now I think it doesn=E2=80=99t interact well with signature aggrega= tion, and > > I worry that it would have some other unexpected effects. c. Generalised > > NOP method: user has to provide the returned value, so even VERIFY-type > > code could do anything >=20 > I see no reason to do either. Gate new behavior based on script execution > flags, which are set based on the script version. Script versions not > understood are treated as "return true" to begin with. The interpreter > isn't even going to try to decode the script according to the old rules, > let alone try to execute it, so there's no reason for the old soft-fork > compatability tricks. >=20 > The new soft-fork trick is that you increment the script version number.= =20 > That is all. This breaks parallel softfork deployments. > > b. scriptWitCode: extra scripts are put in some fixed location in witne= ss > > (Johnson). This makes sure static analysability. c. Extra-data as script > > in OP_CHECKSIG (Luke) >=20 > Propose these as their own script updates. Script versioning makes such > new features cheap. There's no reason to create some sort of complex > omnibus overhaul that does everything. Only if there's common code to implement both versions, which doesn't work = if=20 the changes from A to B to C are drastic. To avoid such drastic changes, th= e=20 overall design/layout needs to at least be planned to cover the desired use= =20 cases in advance. Luke