Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id A133D954 for ; Wed, 8 Jun 2016 08:24:20 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from s37.web-hosting.com (s37.web-hosting.com [198.54.114.154]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 23356129 for ; Wed, 8 Jun 2016 08:24:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xbt.hk; s=default; h=To:References:Message-Id:Cc:Date:In-Reply-To:From:Content-Type: Mime-Version:Subject; bh=TSv2Huq8eYRV2KNE0sEAVNA7ds7f6fDVOYnOdE5sR04=; b=Fqrx Bju/ecpr6b1Uu6Uk88u/o0kBt94bII0rjFU2JD5FX5stpKEBqn6Wi1xtK1K0ulLZKHfkP5EytR21v vthhXdtgKf4AmluQorU+PkssGdt8n2fA57Eefor8FLjUab9txSADfbnMuXhCppY08kkmjTZv06Vh2 wub33gL1A+7akRVXC2tHAR/UG3YseGWJdk4AQrWzjB6hvcho+bfrcZD78C9JKXFoIAezZlhAmp4zJ K5XtKKT0TRVxXKTkn8rpS7jwmigAcvwPUpBzWz9VrsvtSvOqr1cfQo9BpPMRIPBdYftD5RE9AmUA5 0FK8CgHNyjjfPIKGOTgCrJp36NVLlQ==; Received: from [137.189.134.42] (port=60194 helo=[192.168.0.102]) by server37.web-hosting.com with esmtpsa (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.86_1) (envelope-from ) id 1bAYmg-001QxD-HS; Wed, 08 Jun 2016 04:24:18 -0400 Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Content-Type: multipart/signed; boundary="Apple-Mail=_B154EDAD-2DFC-44B9-B519-0A591083CD19"; protocol="application/pgp-signature"; micalg=pgp-sha512 X-Pgp-Agent: GPGMail 2.6b2 From: Johnson Lau In-Reply-To: <201606080729.24789.luke@dashjr.org> Date: Wed, 8 Jun 2016 16:23:51 +0800 Message-Id: References: <201606080729.24789.luke@dashjr.org> To: Luke Dashjr X-Mailer: Apple Mail (2.3124) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - server37.web-hosting.com X-AntiAbuse: Original Domain - lists.linuxfoundation.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - xbt.hk X-Get-Message-Sender-Via: server37.web-hosting.com: authenticated_id: jl2012@xbt.hk X-Authenticated-Sender: server37.web-hosting.com: jl2012@xbt.hk X-Source: X-Source-Args: X-Source-Dir: X-From-Rewrite: unmodified, already matched X-Spam-Status: No, score=-1.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, T_DKIM_INVALID autolearn=no 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 08:24:20 -0000 --Apple-Mail=_B154EDAD-2DFC-44B9-B519-0A591083CD19 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 > On 8 Jun 2016, at 15:29, Luke Dashjr wrote: >=20 > On Wednesday, June 08, 2016 5:57:36 AM Johnson Lau via bitcoin-dev = wrote: >> Why not make it even bigger, e.g. 75 bytes? >=20 > I don't see a sufficient answer to this question. Pieter explained why = >75 > would be annoying, but 75 seems like it should be fine. >=20 >> In any case, since scripts with a 1-byte push followed by a push of = >40 >> bytes remain anyone-can-spend, we always have the option to redefine = them >> with a softfork. >=20 > It's not that simple, since this is preventing use of the witness = field for > such scripts. With this limit in place, any such a softfork would = suddenly > require either two different witness commitments, or disabling the = previous > witness transaction format. >=20 > Luke This is exactly why I proposed to extend the definition. My initial = proposal was extending it to 33 bytes to effectively allow 16*256 new = script versions, assuming we will keep using 32 bytes program hash. 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 = how 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. --Apple-Mail=_B154EDAD-2DFC-44B9-B519-0A591083CD19 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQGcBAEBCgAGBQJXV9YvAAoJEO6eVSA0viTSewcL/ih2CZcIQa8Af1au406/dGfd fThqUNzR/Vkgj42yNHqE0XoL5yHsuHWYmC0+0QtyqqUhggTqlVMNKoxIeMmRmwXP CyZLguiibVNIiuxR6biO1KrxIxVza8nWsA5DLGXPutJyazytE/DFYpK6m71Q2h5x C7K9366tTanj6kboyabUzOvfg6464HNKx93rNzgoWPpCVV+qTlr3focwD5FGFgvC KwTMClULpvAkj6Gji0Qnv9LkgmvrVqsOsMsPAql5KruGaRWrBJ/QxttXlG3IND5V Ix6Bi5OANzurWt5dbO1UPfKQf8LueU53dWAH1/KOfjzdc4ovXvxLp9T+2llsympW oDx75YdaYEptpeaCMxYo9MeulxPNZDXSZkCqoMEHLmkeBm0AeRnrA8f2+wo2sINL 15JZnohyCO3slH5QW31+lM7UFMkRfG75mnp32nH8chcAneO40q10hlumx+eiSQbV T1v68nhjLrxNmazdg4xw88B991+YQWnIzxZxpWe6ZA== =XUsg -----END PGP SIGNATURE----- --Apple-Mail=_B154EDAD-2DFC-44B9-B519-0A591083CD19--