From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id 30E25C002B for ; Tue, 7 Feb 2023 12:50:20 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id F2D1A40516 for ; Tue, 7 Feb 2023 12:50:19 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org F2D1A40516 Authentication-Results: smtp2.osuosl.org; dkim=pass (2048-bit key, unprotected) header.d=messagingengine.com header.i=@messagingengine.com header.a=rsa-sha256 header.s=fm3 header.b=BUIlm+a6 X-Virus-Scanned: amavisd-new at osuosl.org X-Spam-Flag: NO X-Spam-Score: -2.602 X-Spam-Level: X-Spam-Status: No, score=-2.602 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Y78yFaQYTpby for ; Tue, 7 Feb 2023 12:50:18 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org 9317540232 Received: from wout4-smtp.messagingengine.com (wout4-smtp.messagingengine.com [64.147.123.20]) by smtp2.osuosl.org (Postfix) with ESMTPS id 9317540232 for ; Tue, 7 Feb 2023 12:50:18 +0000 (UTC) Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.west.internal (Postfix) with ESMTP id 8CC283200903; Tue, 7 Feb 2023 07:50:16 -0500 (EST) Received: from mailfrontend2 ([10.202.2.163]) by compute5.internal (MEProxy); Tue, 07 Feb 2023 07:50:16 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:date:date:feedback-id :feedback-id:from:from:in-reply-to:in-reply-to:message-id :mime-version:references:reply-to:sender:subject:subject:to:to :x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm3; t=1675774216; x=1675860616; bh=CrlSBVHlovy7gLEhOdbLaecT1V9e EwXZCCxmTmAQktI=; b=BUIlm+a653mvUHk58ecPegIcTDqUv7Vex3Sg5sKNSEPQ QIHHFwK518SXRZwHJLgJVt3NY+xIugNuQg+o0Ex1svapNBgjlxy7GEVFg/PQIOFG UJo6odlB203wOa/iTKetFc4hKZujQKfgnZz9wM6F0Qg0s2tabe7K+l5NA3p3F89a vUN0+yWPaJLpKu2cFMBSFXbjNBe///FhmyhaO99oMHr1S80HrR01vVzS6uY1N+C5 u/Po9bMFE5PKaP4p1y9tN8dqKQpERmFW+obLSaJa2jaXZv6bnhz+r5s+71AXMOHc dmTvU4Rjn0z2lICGIaxv7W8Hq410e7UwM/gMFPVAkg== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvhedrudegkedggedvucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepfffhvfevuffkfhggtggujgesghdtreertddtvdenucfhrhhomheprfgvthgv rhcuvfhougguuceophgvthgvsehpvghtvghrthhouggurdhorhhgqeenucggtffrrghtth gvrhhnpeelvdellefftddukeduffejgfefjeeuheeileeftdfgteduteeggeevueethfej tdenucffohhmrghinhepphgvthgvrhhtohguugdrohhrghenucevlhhushhtvghrufhiii gvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpehpvghtvgesphgvthgvrhhtohguugdr ohhrgh X-ME-Proxy: Feedback-ID: i525146e8:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 7 Feb 2023 07:50:15 -0500 (EST) Received: by localhost (Postfix, from userid 1000) id 421445F824; Tue, 7 Feb 2023 07:50:13 -0500 (EST) Date: Tue, 7 Feb 2023 07:50:13 -0500 From: Peter Todd To: Nadav Ivgi , Bitcoin Protocol Discussion Message-ID: References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="MANY8PoWM0q8mSt7" Content-Disposition: inline In-Reply-To: Subject: Re: [bitcoin-dev] Unenforceable fee obligations in multiparty protocols with Taproot inputs X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 07 Feb 2023 12:50:20 -0000 --MANY8PoWM0q8mSt7 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Feb 07, 2023 at 11:36:58AM +0200, Nadav Ivgi via bitcoin-dev wrote: > > Since Taproot (more generally any kind of MAST) spends have variable si= ze >=20 > Isn't this the case with any arbitrary script execution? Non-taproot This is even been true for P2PKH inputs: you can double the space of your scriptSigs by using uncompressed pubkeys instead of compressed pubkeys. > If the goal is to only allow registering simple singlesig-encumbered UTXOs > like P2(W)PKH, the participants could be asked to prove that their P2TR > output commits to an unspendable script path [0]. Technically, only the last person to sign needs to prove this in advance. Everyone else can prove it with their signatures. This distinction could be useful to support coinjoin participants spending complex P2TR outputs into coinjoins, a perfectly valid use-case in theory so long as they're paying appropriate fees. Though due to how difficult it is = to validate scripts reliably outside the consensus code base, allowing this for arbitrary scripts could lead to DoS attacks where someone takes advantage o= f a bug in script execution to create an invalid transaction. --=20 https://petertodd.org 'peter'[:-1]@petertodd.org --MANY8PoWM0q8mSt7 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE0RcYcKRzsEwFZ3N5Lly11TVRLzcFAmPiSQIACgkQLly11TVR Lzcjaw//XFUHreT7uX9G+6yJ8Xiuomlo8qVcfkMnAXvGz+l7zA4R0xBXRlcTp/WW 3GvyfPnh5NnEf29ctCLiCqp+sWjcxtGjgXu0YD6YQtVtN62bS1rWKFYppqR/Ms7r 6SLH367T51l4JnpaxtfLtmVaBW6bDctBOF4PwEaCD/c5LYQyCQvanXezEYUVi6Tk omjC1dmVn3XVQt1yEyJSfKR3PCe2Raf96SgdCxvFlB80Et8oMItCNYgca5/HlQtL dNnvx9gYsXFhJc7RYoTz3OsoEJOA5DnW9JFDOVams1dXrrkR+HKMPiHsTrDkP0C9 Z9CpwgRYx1k7LyeJCc3xR6NFH444hTuxA9VcYKENFilDErVnLd9FcZ7azLLU49WP gwBMFlEAxTEPP/d1G4W2jgiHvbrlI4LeUXoXTxLLh/s0Yel41s07qFgxZECbcgav j9SbS7pnghfedfI3Z5KxSJ3qLYkSSZQ9Giw25YjpHIxHwHprXjY83yk0SI/fICp9 aanpXwsh6y+RNMQW6/PKMM55LJhrn8r/XK5zs+PsG+HbLei06PHp4QaKWnNlQxfM NftYRSvZj0XgwFHHtZAKse4MWatTAQXThYs7zXu2MgeKzitAoFGfx+9Ktlr/MFjY Kv4QlEadDK+lepT3vwjSP9x1b/X1u15q/d3COIggxat3prSC4NY= =Be1P -----END PGP SIGNATURE----- --MANY8PoWM0q8mSt7--