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 57685C0037 for ; Mon, 15 Jan 2024 23:30:19 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id AB10141DE7 for ; Mon, 15 Jan 2024 23:30:18 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org AB10141DE7 Authentication-Results: smtp4.osuosl.org; dkim=pass (2048-bit key, unprotected) header.d=achow101.com header.i=@achow101.com header.a=rsa-sha256 header.s=protonmail3 header.b=LFdWvZtW X-Virus-Scanned: amavisd-new at osuosl.org X-Spam-Flag: NO X-Spam-Score: -2 X-Spam-Level: X-Spam-Status: No, score=-2 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_SBL_A=0.1] autolearn=ham autolearn_force=no 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 D_JpH2bILiIP for ; Mon, 15 Jan 2024 23:30:17 +0000 (UTC) Received: from mail-0201.mail-europe.com (mail-0201.mail-europe.com [51.77.79.158]) by smtp4.osuosl.org (Postfix) with ESMTPS id 42E8141DDE for ; Mon, 15 Jan 2024 23:30:16 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org 42E8141DDE DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=achow101.com; s=protonmail3; t=1705361406; x=1705620606; bh=ChvbTvTwUdwnkJLeudY28cAwB2KZdggF4DtSVwXycPo=; h=Date:To:From:Subject:Message-ID:Feedback-ID:From:To:Cc:Date: Subject:Reply-To:Feedback-ID:Message-ID:BIMI-Selector; b=LFdWvZtWCUaLr2UAPv72JhwCcxKanMZAN4onfiYVfU4L9wEzWWRLlY3NKcnASpas7 5qjnxur09gsFjdCl2hhAntrPm1C3UQuJhWYbNJBIq9m3mFqM02Pptm5tCY7eJbQ7Kp lNqyFW0DH3o1dNDRKrtYdBDT/iiniomoP9DtQZ2qvOHDNVzSDXv6T7zTAP8euNZ+f5 xPmfh34Zcsw/LJ8Sf4xTbiPaH6/mIgbrsLwz+pWr9wnsBWsamVExtoCck45+FkaBs7 DpGPOZOO2T+1h51OpCZm3sWqojHlgQ5pSG6FOspok1pXtRwxXYqPsZHRHQOhysj+l1 M5A4t28WfSGWg== Date: Mon, 15 Jan 2024 23:29:46 +0000 To: Bitcoin Protocol Discussion , bitcoindev@groups.io From: Ava Chow Message-ID: <5d299fc4-8809-4f32-a9b8-17e353d6ff30@achow101.com> Feedback-ID: 53660394:user:proton MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Mailman-Approved-At: Tue, 16 Jan 2024 00:28:19 +0000 Subject: [bitcoin-dev] MuSig2 derivation, descriptor, and PSBT field BIPs 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: Mon, 15 Jan 2024 23:30:19 -0000 Hi All, In October I sent the MuSig2 descriptor and PSBT field BIPs to the list.=20 Since then, I've made a few changes to the BIPs and am looking for=20 feedback on these. The most significant change is the addition of third BIP which describes=20 how the synthetic xpubs are constructed and derived. This is split from=20 the descriptors BIP as I felt that the PSBT fields BIP needed to=20 reference this process too, and referencing the descriptors BIP for that=20 seemed a bit odd. Otherwise, the descriptors BIP is unchanged, although I am open to=20 Salvatore's suggestion of dropping the ranged derivation within the=20 expression and only allow ranged derivation of the aggregate pubkey itself. I've also made a change to the PSBT fields BIP where the aggregate=20 pubkey is included as a plain pubkey rather than as xonly. I think this=20 change is necessary for to make discovering derived keys easier. The=20 derivation paths for derived keys contain the fingerprint of the parent=20 (i.e. the aggregate pubkey) and the fingerprint requires the evenness=20 bit to be serialized. So the aggregate pubkey in the PSBT fields need to=20 contain that evenness information in order for something looking at only=20 the PSBT to be able to determine whether a key is derived from an=20 aggregate pubkey also specified in the PSBT. The full text of the BIPs can be found at the following: * Derivation:=20 https://github.com/achow101/bips/blob/musig2/bip-musig2-derivation.mediawik= i * Descriptors:=20 https://github.com/achow101/bips/blob/musig2/bip-musig2-descriptors.mediawi= ki * PSBT:=20 https://github.com/achow101/bips/blob/musig2/bip-musig2-psbt.mediawiki Thanks, Ava Chow