Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 09604EF6 for ; Tue, 30 Jan 2018 07:27:24 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from outmail148106.authsmtp.co.uk (outmail148106.authsmtp.co.uk [62.13.148.106]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 3D2E41C0 for ; Tue, 30 Jan 2018 07:27:23 +0000 (UTC) Received: from mail-c245.authsmtp.com (mail-c245.authsmtp.com [62.13.128.245]) by punt21.authsmtp.com. (8.15.2/8.15.2) with ESMTP id w0U7RKt5068106; Tue, 30 Jan 2018 07:27:20 GMT (envelope-from pete@petertodd.org) Received: from petertodd.org (ec2-52-5-185-120.compute-1.amazonaws.com [52.5.185.120]) (authenticated bits=0) by mail.authsmtp.com (8.15.2/8.15.2) with ESMTPSA id w0U7RINt016009 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Tue, 30 Jan 2018 07:27:19 GMT (envelope-from pete@petertodd.org) Received: from [127.0.0.1] (localhost [127.0.0.1]) by petertodd.org (Postfix) with ESMTPSA id 28FCB4009E; Tue, 30 Jan 2018 07:27:18 +0000 (UTC) Received: by localhost (Postfix, from userid 1000) id 75E082062F; Tue, 30 Jan 2018 02:27:16 -0500 (EST) Date: Tue, 30 Jan 2018 02:27:16 -0500 From: Peter Todd To: Gregory Maxwell , Bitcoin Protocol Discussion Message-ID: <20180130072716.GB1095@fedora-23-dvm> References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="p4qYPpj5QlsIQJ0K" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-Server-Quench: 01a1a767-058f-11e8-9f3b-9cb654bb2504 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCd2Yg0TA1ZNQRgX IjsJECJaVQIpKltL GxAVKBZePFsRUQkR aQdMdQIUElQaAgsB Am4bW1NeUlp7W2M7 bghPaBtcak9QXgdq T0pMXVMcUwUNBn54 eFoeUx9ydwwIcHp5 ZghiXyFaDUN8clt9 R0YCCGwHMG99YTYc Al1RJFFSdQcYLB1A alQxNiYHcQ5VPz4z GA41ejw8IwAXCCNK CggGJk8ISFoGVjcm SlgeHThnN0wZTCIy KVQ6K1sRB1oYN10p ZjMA 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=-2.6 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_LOW 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] How accurate are the Bitcoin timestamps? 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: Tue, 30 Jan 2018 07:27:24 -0000 --p4qYPpj5QlsIQJ0K Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jan 29, 2018 at 09:54:23PM +0000, Gregory Maxwell via bitcoin-dev w= rote: > If times need to be accurate Bitcoin would need to use a rather > different design (e.g. each block would commit to the observation time > of the prior N blocks, and an iterative algorithm would solve for each > blocks time and each miners local offset). >=20 > IIRC open-timestamp calendar servers provide more precise > time-stamping under the assumption that the calendar server is > behaving correctly. That is incorrect. The OpenTimestamps servers are specifically designed not= to be trusted, and thus do not make any cryptographically verifiable attestati= ons as to when timestamps were created. In the future I expect to add a trusted timestamping scheme via disposable = keys to the OpenTimestamps protocol, but that work isn't yet complete: https://lists.opentimestamps.org/pipermail/ots-dev/2017-May/000001.html --=20 https://petertodd.org 'peter'[:-1]@petertodd.org --p4qYPpj5QlsIQJ0K Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEFcyURjhyM68BBPYTJIFAPaXwkfsFAlpwHlAACgkQJIFAPaXw kfu3Ugf7BTcQmm/mEFS+gvQnOYMLFD498k2TitMYGA8a47j9PvKslYSZWeYjmOoM 2q/cKw1oPOkIONCryJMLQUde421LFT1L8PZzwpxT0qIeZ96NkcXvfaQhzEZE7Uwp kcuAmBVzJRAipXOcGtMQTg6FmBFMK5a1wGVjDlZGfCYJpUvw2FyBfTTy2NlNSbXO CgU4nbwZvK6BaAucn71Xv6o842kIkYTsftWXUzs2hmF21ijlQ3sSxJznUtIALhXR tbd+WVWT74uXyBO0HB14myJfUMmD3vUyFn9zJwVlIGGTON1/DkOEBMeL7zA7ugqR i4TTvFxiC3/9oAKLsGc8DGCtqd3bZg== =13Pp -----END PGP SIGNATURE----- --p4qYPpj5QlsIQJ0K--