From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 8F5B592B for ; Wed, 8 Jun 2016 16:45:45 +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 2E69E217 for ; Wed, 8 Jun 2016 16:45:45 +0000 (UTC) Received: from ishibashi.localnet (unknown [IPv6:2001:470:5:265:61b6:56a6:b03d:28d6]) (Authenticated sender: luke-jr) by zinan.dashjr.org (Postfix) with ESMTPSA id 542CC38A17C5; Wed, 8 Jun 2016 16:45:13 +0000 (UTC) X-Hashcash: 1:25:160608:jl2012@xbt.hk::P8dNxquYYhTrYBZG:cX+WP X-Hashcash: 1:25:160608:bitcoin-dev@lists.linuxfoundation.org::dJaf9w/S2qwsBGSy:arpEp From: Luke Dashjr To: Johnson Lau Date: Wed, 8 Jun 2016 16:45:10 +0000 User-Agent: KMail/1.13.7 (Linux/4.1.18-gentoo; KDE/4.14.16; x86_64; ; ) References: <201606080729.24789.luke@dashjr.org> In-Reply-To: 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: <201606081645.12598.luke@dashjr.org> X-Spam-Status: No, score=-3.3 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD autolearn=ham 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] BIP141 segwit consensus rule update: extension of witness program definition 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: Wed, 08 Jun 2016 16:45:45 -0000 On Wednesday, June 08, 2016 8:23:51 AM Johnson Lau wrote: > If someday 32 bytes hash is deemed to be unsafe, the txid would also be > unsafe and a hard fork might be needed. Therefore, I don=E2=80=99t see ho= w a > witness program larger than 40 bytes would be useful in any case (as it is > more expensive and takes more UTXO space). I think Pieter doesn=E2=80=99t= want to > make it unnecessarily lenient. There is no harm in being lenient, but it limits the ability to do softfork= =20 upgrades in the future. I appreciate Pieter's concern that we'd need to do= =20 more development and testing to go to this extreme, which is why I am only= =20 asking the limit raised to 75 bytes. Luke