Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id E9E204A4 for ; Tue, 18 Dec 2018 04:58:35 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from azure.erisian.com.au (cerulean.erisian.com.au [139.162.42.226]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 18074CF for ; Tue, 18 Dec 2018 04:58:34 +0000 (UTC) Received: from aj@azure.erisian.com.au (helo=sapphire.erisian.com.au) by azure.erisian.com.au with esmtpsa (Exim 4.89 #1 (Debian)) id 1gZ7Sg-0004EN-VZ; Tue, 18 Dec 2018 14:58:32 +1000 Received: by sapphire.erisian.com.au (sSMTP sendmail emulation); Tue, 18 Dec 2018 14:58:26 +1000 Date: Tue, 18 Dec 2018 14:58:26 +1000 From: Anthony Towns To: Bitcoin Protocol Discussion Message-ID: <20181218045826.2latx2rdyzsuc77k@erisian.com.au> References: <20181214104839.ur4lde3dzncadmr4@erisian.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) X-Spam-Score: -1.9 X-Spam-Score-int: -18 X-Spam-Bar: - X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org X-Mailman-Approved-At: Tue, 18 Dec 2018 16:11:00 +0000 Subject: Re: [bitcoin-dev] Schnorr and taproot (etc) upgrade 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: Tue, 18 Dec 2018 04:58:36 -0000 On Mon, Dec 17, 2018 at 10:18:40PM -0500, Russell O'Connor wrote: > On Mon, Dec 17, 2018 at 3:16 PM Johnson Lau wrote: > But I’m not sure if that would do more harm than good. For example, people > might lose money by copying an existing script template. But they might > also lose money in the same way as CHECKMULTISIG is disabled. So I’m not > sure. Well, if CHECKSIG* and CHECKMULTISIG* are all disabled in favour of CHECKDLS, CHECKDLSVERIFY and CHECKDLSADD with both different names and different opcodes, copying a script template opcode-for-opcode from v0 to v1 will always fail. (With taproot, this doesn't necessarily mean you lose money, even if the script is impossible to ever satisfy, since you may be able to recover via the direct signature path) > Another related thing I’d like to bikeshed is to pop the stack after > OP_CLTV and OP_CSV. The same pros and cons apply. > This one is almost a no-brainer I think.  Nearly every instance of OP_CSV is > followed by an OP_DROP and we'd save 1 WU per OP_CSV if we pop the stack > afterwards. It's definitely bikeshedding so whatever; but to me, it seems like it'd be easier for everyone to have it so that if you've got the same opcode in v0 script and v1.0 script; they have precisely the same semantics. (That said, constructions like " CLTV

CHECKSIGVERIFY" that avoid the DROP and work when you're expected to leave a true value on the stack won't work if you have to end up with an empty stack) Cheers, aj