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 1048ABDE for ; Thu, 7 Sep 2017 18:38:51 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from mail.sldev.cz (mail.sldev.cz [51.254.7.247]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id AFEA18A for ; Thu, 7 Sep 2017 18:38:50 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by mail.sldev.cz (Postfix) with ESMTP id 0A86DEB43; Thu, 7 Sep 2017 18:58:58 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at mail.sldev.cz Received: from mail.sldev.cz ([127.0.0.1]) by localhost (mail.sl [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 8rfms0Jd00ip; Thu, 7 Sep 2017 18:58:57 +0000 (UTC) Received: from tetra.site (unknown [10.8.8.107]) by mail.sldev.cz (Postfix) with ESMTPSA id 50B62EB5B; Thu, 7 Sep 2017 18:58:53 +0000 (UTC) To: Jonas Schnelli , Bitcoin Protocol Discussion References: <0d405f5d-c0a4-bad7-b6c3-08ba4424bf17@satoshilabs.com> From: Pavol Rusnak Message-ID: Date: Thu, 7 Sep 2017 20:38:37 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="PkCxvxk8lwmxlScrgErUskeMPj0amS5Fl" X-Spam-Status: No, score=0.0 required=5.0 tests=none autolearn=disabled version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Subject: Re: [bitcoin-dev] Proposal: Extended serialization format for BIP-32 wallets 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: Thu, 07 Sep 2017 18:38:51 -0000 This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --PkCxvxk8lwmxlScrgErUskeMPj0amS5Fl Content-Type: multipart/mixed; boundary="dP96ABUSmh84nMHujMdaiqwSa7oOMjv8K"; protected-headers="v1" From: Pavol Rusnak To: Jonas Schnelli , Bitcoin Protocol Discussion Message-ID: Subject: Re: [bitcoin-dev] Proposal: Extended serialization format for BIP-32 wallets References: <0d405f5d-c0a4-bad7-b6c3-08ba4424bf17@satoshilabs.com> In-Reply-To: --dP96ABUSmh84nMHujMdaiqwSa7oOMjv8K Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 07/09/17 18:47, Jonas Schnelli wrote: > But not sure if it=E2=80=99s worth to save ~two bytes for that. I think it's not worth complicating the field just to save two bytes. But if we agree (for privacy reasons) that resolution of this field should be reduced to week-level (as suggested by Jonas) or month-level (as sugested by Peter), we could use just 16 bits for this. TBH I think TREZOR will provide hardcoded constant for this field (1.1.2014 for all its P2PKH xpubs and 1.8.2017 for all its P2WPKH-in-P2SH xpubs). So no privacy is lost in this case, but if we want to ENFORCE this on BIP level, we should decrease the resolution. > 2. > Would it make sense to have special depth bytes that directly implies i= t=E2=80=99s a BIP44 master key (and therefore avoid the bip32 path serial= isation)? I know some =E2=80=9Ecentralised=E2=80=9C table need to be avai= lable for that which may be not a good idea. But maybe the BIP could rese= rve a couple of depth-bytes (maybe 0xF0 to 0xFF) for predefined paths. I think this is exactly what Thomas meant by "wallet developers are going to use dirtier tricks" in his email, that's why I specifically tried to avoid this. I see no good reason to do this, unless we want to save some bytes and I don't think we are in need of doing this. > 3. > Would adding a version bit make sense to allow future extensions? I think changing the human-readable part is the way to go. That way the wallet can immediately say if it understands the format or not, without parsing the binary data contents. Version bits were introduced in older standards, because there was no such thing as human-readable prefix. --=20 Best Regards / S pozdravom, Pavol "stick" Rusnak CTO, SatoshiLabs --dP96ABUSmh84nMHujMdaiqwSa7oOMjv8K-- --PkCxvxk8lwmxlScrgErUskeMPj0amS5Fl Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEhuZ5L8J7/UeIYMEQkfOzObmgKj0FAlmxki4ACgkQkfOzObmg Kj10XQ//Zxj9HGQPzm9lOXEOpePdT2xiJJ6IBhxgZ/F1C+26kj/A6bHGOJDW9IP7 8l4GVuFAAsSeYV8dkAZOWv3euAFMV3no/fvw2o9dnYNVTqPE1oJ5cAFVJNXFkMiN HfMojLSOmr85OyipuXcRkhgY+or52ZzjSaOxxg3BuIstwaKiwpRCQRZTVYx+13Jm G+zKArSln6v2Vj3+zbYw92EI2/9N0MWWFG3ZKfKJ+51U3Os0DD1CPELLr+Y7wL4p HdwdQ9f7W4xFg64oyrSOUgDzQyi8zJ7DWXdx/oI2uU7ODu+nSXX6arXfOy67Gq4S Lx7HTdRA55gE1oHXn2G/+lftZFJitPx/Xoz9Zkzoei/xqcevaK35tKhcKBTg+Mt6 Hnw6ij7fe2Xm9Ty7t1J+QWnMqZb9oppGm0KKwZ+MoDMG2GXhELYJHDxjIB/R6lZW NSmJLH+8U1vAamvy1SkSAkCJcq86Z+y+mb4MlOBsDjj6/1kPYfznX0pM2elMWYeu K/XnTUj0mPdFo4OD9cbkF9HKCbNDulDdo/ntyNnFaNcAGnl5hkhJnez98Nwb8l8i XN4sgM5TjTGc4mqvf2F8AXhhqkjhMUxCQot4as7KbehDMweMdbWJCjttqSBGiHFd YkKXQNGgeOB9/3UTULJuXy3y2val478S+4Dq2rPd/23yGguF9Oo= =uJt5 -----END PGP SIGNATURE----- --PkCxvxk8lwmxlScrgErUskeMPj0amS5Fl--