From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 2C256C000E for ; Sun, 25 Jul 2021 05:39:34 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 13204403E4 for ; Sun, 25 Jul 2021 05:39:34 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org X-Spam-Flag: NO X-Spam-Score: 3.509 X-Spam-Level: *** X-Spam-Status: No, score=3.509 tagged_above=-999 required=5 tests=[BAYES_40=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_SBL_CSS=3.335, RCVD_IN_XBL=0.375, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=no autolearn_force=no Authentication-Results: smtp4.osuosl.org (amavisd-new); dkim=pass (1024-bit key) header.d=dtrt.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 3MbHRHJgdneU for ; Sun, 25 Jul 2021 05:39:33 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from newmail.dtrt.org (newmail.dtrt.org [IPv6:2600:3c03::f03c:91ff:fe7b:78d1]) by smtp4.osuosl.org (Postfix) with ESMTPS id 07934403E3 for ; Sun, 25 Jul 2021 05:39:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=dtrt.org; s=20201208; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID: Subject:To:From:Date:Sender:Reply-To:Cc:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=43yd9XCpSHv9yeFEiA0QyBZbIVs7CQEXvAVsBRTwHFg=; b=W7nIaQ+YHUHgWu22GTE0QVKSdp 8VNxbb972vXKc+YLeoDqlvRTERItbm3/HIOHzKkQsHLD5cWMT69hHGgFSVIVR51Yld29IDVmWIDex fp1SwMc+Ys5bTNRREuy9+ljPwDT9sJ6FWsA45SBUZuSmavFfYyA0uCKDDD4Dzv95uOj4=; Received: from harding by newmail.dtrt.org with local (Exim 4.92) (envelope-from ) id 1m7WrL-0003JX-2P; Sat, 24 Jul 2021 19:39:31 -1000 Date: Sat, 24 Jul 2021 19:38:03 -1000 From: "David A. Harding" To: Billy Tetrud , Bitcoin Protocol Discussion Message-ID: <20210725053803.fnmd6etv3f7x3u3p@ganymede> References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="mk4ogpppwgik6ngy" Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716 Subject: Re: [bitcoin-dev] Covenant opcode proposal OP_CONSTRAINDESTINATION (an alternative to OP_CTV) 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: Sun, 25 Jul 2021 05:39:34 -0000 --mk4ogpppwgik6ngy Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Jul 20, 2021 at 10:56:10PM -0700, Billy Tetrud via bitcoin-dev wrote: > This involves [...] constraining the amount of the fee that output is > allowed to contribute to. [...] fee is specified relative to recent > median fee rates - details in the proposal). Here are the relevant details: > The medianFeeRate is defined as the median fee rate per vbyte for the > most recent windowLength blocks. The maxFeeContribution is defined as > medianFeeRate * 2^feeFactor of the fee. Note that this is a limitation > on the fee, not on the fee-rate. If feeFactor is -1, > maxFeeContribution is 0. First, I don't think we want full nodes to have to store the feerate for every transaction in a 3,000 block window (~2.5 million txes, assuming all segwit). I'm sure you could tweak this proposal to require a much smaller dataset. Second, I think this requires careful consideration of how it might affect the incentives for miners. Miners can include many small high-fee pay-to-self transactions in their blocks to raise the median feerate, but this puts them at increased risk of fee sniping from other miners, which may incentivize fee-raisers to centralize their mining, which is ultimately bad. I'm not sure that's a huge concern with this proposal, but I think it and other incentive problems require consideration. Finally, I think this fee mechanism is redundant. For any case where this opcode will be used, you'll want to have two things: 1. A mutual spend clause (e.g. a multisignature taproot keypath spend) where all parties agree on a spend of the output and so can set an appropriate feerate at that time. You want this because it'll be the most efficient way to spend. 2. A fee override that allows paying additional fees beyond what OP_CONSTRAINDESTINATION allows, either through attaching an additional input or through CPFP. You want this because you will know more about feerate conditions at spend time than you did when you created the receiving script. If you have the ability to choose feerates through the above mechanisms, you don't need a constrained feerate mechanism that might be manipulable by miners. (I haven't looked closely at the rest of your proposal; the above just caught my attention.) -Dave --mk4ogpppwgik6ngy Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEEgxUkqkMp0LnoXjCr2dtBqWwiadMFAmD8+LsACgkQ2dtBqWwi adPpIBAAscWZFxXnh6Q/ourAnp9j9cNM6A/v7sQOO7rlr+t/+/HtpgD9lBxuAn1z GChb/bo0ATVgaer8JlVUlJEDUoePQz9PFtfU3sGRUc3efHEu5JDATgsl/ZwrFVTz Awrref8shk4BSSqXOFrd3MsJ9tqnZ9iuT26TxQlCniNxFJSIEOc1749H/XVgOgd7 Uw4iKpzGvXGD1VKOThhYz8tNQi9Hj9k6P9HtwOyDNah7N3PCSoUuYC5vT1sQ1uze XscOlNU03xdKgUS6woFd4MXUwDAhk0VpsDOg6henj6+8ufyPeSQXJYT3TVBWYVGl s7wjAsgpL8ZluBZSxx3gbnrRVxp09OWP/hf6/6cSs3QCIaAt37nLCpWBcodo+r/o hAgvixUP0DNBspZblxoNK3ayLSWJFCAig8OI5YflX0nZRdiF09lS9cnsphN1bPwu E5hJ4JjCIIUf/tVNX8pHzpu+/4se9aLdNr4HrMaOjc9Hc9fm34XFt3hUKzpvLiXV Jp7s058onDlgTKHHIfY0bP3WUWNZNKR6PqKtGjMlVaiQAaxctGno12K8e5gbHKUl yIRFnNUdmgJGhnp39UWWVGJEoLV4nc7gRVTws+I24RnGFdlQP5gTpdYjcZUNkk+N ZL3Le4jGNS+mNILLqim/NbFMZHH1ezg5N1vXG7k1XA5CNkJeJrA= =uh2t -----END PGP SIGNATURE----- --mk4ogpppwgik6ngy--