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 D697CD38 for ; Mon, 13 Aug 2018 20:39:54 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-ua1-f46.google.com (mail-ua1-f46.google.com [209.85.222.46]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id A3F27165 for ; Mon, 13 Aug 2018 20:39:53 +0000 (UTC) Received: by mail-ua1-f46.google.com with SMTP id w7-v6so10735208uan.9 for ; Mon, 13 Aug 2018 13:39:53 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=npFLmi4dntgbk+NHEVrVZrjzVi6MyaX2Pi2IPC41EG8=; b=AlpG9dTcE73h6KGv4Fk9IuOLt8i+HaVdNtD4WrEED+KsnIm1H2GRFnfHJNkdUK0Phs TNtflDYTLctPrNLwfyoNoKWGQOf8YwrNmUMh5tl67aF5dK15MX5ZkWIUURspM7+10O0A OrrmAe7AbgLv6w58NLsDzUJay1xF9N5yOrzsYcGUncj4WGRCD8K+E+m4dIW0SxtH3oNG bk0265G1PJvLMKZpW0SZWSBC5Duvtf7v4wb6tWAMeFWhvoayJ/KwKWJqKk8zdVPvJNw8 dxgLsJLDuS/a3O0jUtF976C1xHKOMyyOD9asicDWykKi+7B7EeLUCRRz10u+iTyh3E1J npeg== X-Gm-Message-State: AOUpUlEE8sQ6kmBYQ68tY5olh9c91S98CCKYdHrUoEaPHOJx9iL25T4u Ums1W9jbpE/ilJNevG+tOsuJzsOYZRhi5QkOuAk= X-Google-Smtp-Source: AA+uWPwXe4hLBR/TORpwbhC+l3j7eWrjohK5t9pnMFgtMEavKYmDv1JcjeupIGmqHYb067EvND4zWG3CdIHJ1tBCJ4A= X-Received: by 2002:a1f:aa8a:: with SMTP id t132-v6mr12295803vke.80.1534192792683; Mon, 13 Aug 2018 13:39:52 -0700 (PDT) MIME-Version: 1.0 References: <7A_00K2wcfdgZMimY9aZ4gUFWyVIPOVrnueAFAosM-S-gIIoHXez6v5GcC8OrfTULz0NZ6n1g3T9jfVbgBvU_jKbgmNd-zlVqQVOC00NphA=@achow101.com> In-Reply-To: <7A_00K2wcfdgZMimY9aZ4gUFWyVIPOVrnueAFAosM-S-gIIoHXez6v5GcC8OrfTULz0NZ6n1g3T9jfVbgBvU_jKbgmNd-zlVqQVOC00NphA=@achow101.com> From: Gregory Maxwell Date: Mon, 13 Aug 2018 20:39:38 +0000 Message-ID: To: achow101-lists@achow101.com, Bitcoin Dev Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Subject: Re: [bitcoin-dev] Witness serialization in PSBT non-witness UTXOs 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: Mon, 13 Aug 2018 20:39:55 -0000 An alternative is to require reading either or but also require writing without the witness. It's likely that two years from now, nothing will write the witnesses, and the requirement to support reading them could be dropped. On Mon, Aug 13, 2018 at 8:32 PM Achow101 via bitcoin-dev wrote: > > Hi, > > Since the BIP is already in proposed status, I think that we should speci= fy the non-witness utxo to just be "witness or non-witness" serialization. = This maintains compatibility with things that have already implemented but = also maintains the forwards compatibility that is needed. > > Andrew > > > =E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90 Original = Message =E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90 > On August 13, 2018 11:56 AM, Pieter Wuille via bitcoin-dev wrote: > > > Hello all, > > > > BIP174 currently specifies that non-witness UTXOs (the transactions > > being spent by non-witness inputs) should be serialized in network > > format. > > > > I believe there are two issues with this. > > > > 1. Even in case the transaction whose output being spent itself has a > > witness, this witness is immaterial to PSBT. It's only there to be > > able to verify the txid commits to the output/amount being spent, > > which can be done without witness. > > > > 2. "Network format" is a bit ambiguous. We can imagine a future > > softfork that introduces a new type of witness. Network format coul= d > > be interpreted as including that new witness type, which is clearly > > unnecessary (by the above argument), and would gratuitously break > > compatibility with existing signers if implemented pedantically. > > > > So my suggestion is to update the specification to state that > > non-witness UTXOs must be serialized without witness. If it's too l= ate > > for that, it should instead be updated to explicitly specify with o= r > > witnout witness, but it's safe to drop the witness. > > > > Opinions? > > > > Cheers, > > > > -- > > Pieter > > > > > > bitcoin-dev mailing list > > bitcoin-dev@lists.linuxfoundation.org > > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > > > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev