Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 581A5407 for ; Thu, 10 May 2018 03:07:55 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mail5.protonmail.ch (mail5.protonmail.ch [185.70.40.28]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 7541CB0 for ; Thu, 10 May 2018 03:07:54 +0000 (UTC) Date: Wed, 09 May 2018 23:07:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=default; t=1525921671; bh=QcZdSXGJccZmWJ0y655nCiw4n3w4RBh4Rok1yMfshTU=; h=Date:To:From:Cc:Reply-To:Subject:In-Reply-To:References: Feedback-ID:From; b=GKEjsoaKdWbGCIIgrrdHkGdJr31Cb4K8v/Oh1ZN+fMnVTQBF5DKopUGD03Q1gFbUJ V98Wc9qRqAxAI4Jw/FjpFs1e2ZcOPb3MOQGH3h1S5UMV8BhDmAN+levVX2RKmFzZQ+ OJzmsq7SYwD5mCBGfw/QCOuBUCnch6523Kalku9c= To: Luke Dashjr , Bitcoin Protocol Discussion From: ZmnSCPxj Reply-To: ZmnSCPxj Message-ID: In-Reply-To: <201805100227.42217.luke@dashjr.org> References: <87po25lmzs.fsf@rustcorp.com.au> <201805100227.42217.luke@dashjr.org> Feedback-ID: el4j0RWPRERue64lIQeq9Y2FP-mdB86tFqjmrJyEPR9VAtMovPEo9tvgA0CrTsSHJeeyPXqnoAu6DN-R04uJUg==:Ext:ProtonMail MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-2.2 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, FROM_LOCAL_NOVOWEL, RCVD_IN_DNSWL_LOW 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: Thu, 10 May 2018 03:08:15 +0000 Subject: Re: [bitcoin-dev] Making OP_TRUE standard? 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: Thu, 10 May 2018 03:07:55 -0000 Good morning Luke and list, > An OP_TRUE-only script with a low value seems like a good example of wher= e the >=20 > weight doesn't reflect the true cost: it uses a UTXO forever, while only >=20 > costing a weight of 4. >=20 > I like Johnson's idea to have some template (perhaps OP_2-only, to preser= ve >=20 > expected behaviour of OP_TRUE-only) that when combined with a 0-value is >=20 > always valid only if spent in the same block. I understand the issue. On Lightning side, if this rule is used, we would = have the two options below: 1. Commitment transactions always use the minimum feerate, but always have= the above OP_TRUE output. Then to confirm the commitment transaction we w= ould have to always spend the OP_TRUE output in CPFP transaction that pays = for actual fee at unilateral close. This consumes more blockchain space fo= r unilateral closes, as the second transaction is always mandatory. 2. We store two commitment transactions and associated paraphernalia (furt= her transactions to claim the HTLCs). One version has a negotiated feerate= without the OP_TRUE output. The other version has a slightly increased fe= erate and an OP_TRUE output as above. At unilateral close, we see if the n= egotiated feerate is enough and use that version if possible, but if not we= RBF it with other version and in addition also CPFP on top. As mentioned = before, we do not have transaction packages, so we need to RBF with higher = feerate the commitment transaction, then submit the CPFP transaction which = makes the first transaction valid to include in a block as per the rule. T= his requires that the fallback always have both an RBF bump and a CPFP bump= . >=20 >(Maybe it should be the first output >=20 > instead of the last... Is there any legitimate reason one would have mult= iple >=20 > such dummy outputs?) It seems there are indeed none. Regards, ZmnSCPxj