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 95ED3B10 for ; Thu, 7 Sep 2017 18:09:12 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from outmail149077.authsmtp.com (outmail149077.authsmtp.com [62.13.149.77]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id E7039D3 for ; Thu, 7 Sep 2017 18:09:11 +0000 (UTC) Received: from mail-c245.authsmtp.com (mail-c245.authsmtp.com [62.13.128.245]) by punt23.authsmtp.com (8.14.2/8.14.2/) with ESMTP id v87I99em014508; Thu, 7 Sep 2017 19:09:09 +0100 (BST) Received: from petertodd.org (ec2-52-5-185-120.compute-1.amazonaws.com [52.5.185.120]) (authenticated bits=0) by mail.authsmtp.com (8.14.2/8.14.2/) with ESMTP id v87I96hw083766 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 7 Sep 2017 19:09:07 +0100 (BST) Received: from [127.0.0.1] (localhost [127.0.0.1]) by petertodd.org (Postfix) with ESMTPSA id D9AE240122; Thu, 7 Sep 2017 18:09:05 +0000 (UTC) Received: by localhost (Postfix, from userid 1000) id 1E960202B4; Thu, 7 Sep 2017 14:09:02 -0400 (EDT) Date: Thu, 7 Sep 2017 14:09:02 -0400 From: Peter Todd To: Jonas Schnelli , Bitcoin Protocol Discussion Message-ID: <20170907180902.GC13727@fedora-23-dvm> References: <0d405f5d-c0a4-bad7-b6c3-08ba4424bf17@satoshilabs.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="aT9PWwzfKXlsBJM1" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-Server-Quench: a4199ed4-93f7-11e7-801f-9cb654bb2504 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCd2Yg0TA1ZNQRgX IjsJECJaVQIpKltL GxAVKBZePFsRUQkR aQdMdgUUC1AEAgsB AmEbWl1eUFR7WWQ7 bghPaBtcak9QXgdq T0pMXVMcUg1veBUH XlkeWhp1cQMIcXty YAgzWnFSVREucVt0 QRhTCGwHMGB9YGAe Bl1RJFFSdQcYLB1A alQxNiYHcQ5VPz4z GA41ejw8IwAXED5S WgYWJFZACWsbAjM6 Sx0OVS4iB0wMQyQh JgAnLVhUEkELN0wu eVUmQxoyEidXUVc8 V15EBCtUO0Jp X-Authentic-SMTP: 61633532353630.1039:706 X-AuthFastPath: 0 (Was 255) X-AuthSMTP-Origin: 52.5.185.120/25 X-AuthVirus-Status: No virus detected - but ensure you scan with your own anti-virus system. X-Spam-Status: No, score=-0.7 required=5.0 tests=RCVD_IN_DNSWL_LOW 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 18:09:12 -0000 --aT9PWwzfKXlsBJM1 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Sep 07, 2017 at 09:47:16AM -0700, Jonas Schnelli via bitcoin-dev wr= ote: > Thanks for the proposal. >=20 > Three points it could see as possible improvements: >=20 > 1. > From what I know, the exact birthday in seconds doesn=E2=80=99t matter th= at much therefore it may be possible to just use 13 or 16bits to create a r= epresentation in week from 2009-01-09 00:00 UTC. 13bits would give you 157 = years. > Always round down to the beginning of the week when the key was created. > But not sure if it=E2=80=99s worth to save ~two bytes for that. > Also not sure if the key-birthday in seconds could have a security or pri= vacy implication (week maybe better). Note how private key birthday is a potential privacy issue in certain cases. Rare of course, because usually you don't release your private keys! But us= ers will on occasion have those keys be compromised. Personally, I'd advocate rounding down to month-level resolution, as that should be both enough to handle any likely reorg scenario, and it's still a precision that won't add much extra scanning ot any reasonably old (~1yr) wallet. Note also how if transactions created with private keys in a seed use nLockTime, you can ensure coins won't exist in a block older than the seed birthday by simply ensuring that nLockTime is set to a more recent date then that birthday under all circumstances. --=20 https://petertodd.org 'peter'[:-1]@petertodd.org --aT9PWwzfKXlsBJM1 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- iQEcBAEBCAAGBQJZsYs8AAoJECSBQD2l8JH7RFwH/1jKoPajttjH8BlRBesyIgb+ CH20efFM3OhvwXer4/a9nUGi4JisFbxSnatF4Ujp+uPeDBTk3vr6lgf04Q3fvHSu KGWkZZrLnR3FoGVTzCQ32+ubZpr8eKC7OkIDPdj39O93Y1/JPGnFx4Bf2pHVG7tb ugcpGzEFgk2xJiqUeYp10PaoNcsHibzJLBN9J3JguqiuDY7XQ56q+R03DjahB6Gn tCrEstma4jU7yewsduFaQH3SyLKLV5mN1gTSK5E5/fstjIC/M3scvuk2oeQdPI1I NT69RmGFALGrTW2tP6qW+CL1sa5OBZKllG9PVuBI8Ao043ff3GXjxlvB2UNfP+k= =kiSk -----END PGP SIGNATURE----- --aT9PWwzfKXlsBJM1--