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 EFA31E7E for ; Tue, 9 Jan 2018 00:37:31 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from outmail149101.authsmtp.com (outmail149101.authsmtp.com [62.13.149.101]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 5E970A3 for ; Tue, 9 Jan 2018 00:37:31 +0000 (UTC) Received: from mail-c245.authsmtp.com (mail-c245.authsmtp.com [62.13.128.245]) by punt22.authsmtp.com. (8.15.2/8.15.2) with ESMTP id w090bSKH084547; Tue, 9 Jan 2018 00:37:28 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 w090bRPq006714 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Tue, 9 Jan 2018 00:37:28 GMT (envelope-from pete@petertodd.org) Received: from [127.0.0.1] (localhost [127.0.0.1]) by petertodd.org (Postfix) with ESMTPSA id C2AA140110; Tue, 9 Jan 2018 00:37:26 +0000 (UTC) Received: by localhost (Postfix, from userid 1000) id C8315208A8; Mon, 8 Jan 2018 19:37:25 -0500 (EST) Date: Mon, 8 Jan 2018 19:37:25 -0500 From: Peter Todd To: Ben Kloester Message-ID: <20180109003725.GA21800@savin.petertodd.org> References: <20180108124506.GA13858@savin.petertodd.org> <5c229def-760a-69eb-e646-bd3c77482b00@satoshilabs.com> <20180108193714.GA15359@savin.petertodd.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="+QahgC5+KEYLbs62" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-Server-Quench: 4548eb0c-f4d5-11e7-9f3b-9cb654bb2504 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCd2Yg0TA1ZNQRgX IjsJECJaVQIpKltL GxAVKBZePFsRUQkR aQdMdgsUElQaAgsB Am4bW1ReU1p7W2s7 bghPaBtcak9QXgdq T0pMXVMcUwVhAU5j Zl8eUh91dgEIcXdx YAhmW3RTCRZ6Jlsr RhpRCGwHMGB9YTYc Al1RJFFSdQcYLB1A alQxNiYHcQ5VPz4z GA41ejw8IwAXEy1J RRoNLFYbS11DBTM3 XR0eVS4vFFcIS20r NR04I0IRVEUcIw0p OlssXF9w 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 Cc: Bitcoin Protocol Discussion Subject: Re: [bitcoin-dev] Satoshilabs secret shared private key scheme 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, 09 Jan 2018 00:37:32 -0000 --+QahgC5+KEYLbs62 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jan 09, 2018 at 09:26:17AM +1100, Ben Kloester wrote: > > This sounds very dangerous. As Gregory Maxwell pointed out, the key > derivation > > function is weak enough that passphrases could be easily brute forced >=20 > So you are essentially imagining that a perpetrator will combine the > crypto-nerd fantasy (brute forcing the passphrase) *with* the 5-dollar > wrench attack, merging both panes of Randall Munroe's comic? Seems > vanishingly unlikely to me - attackers are generally either the wrench > type, or the crypto-nerd type. We're talking about seeds here, not hardware wallets. For a hardware wallet theft scenario, if you're worried about muggers you c= an make the hardware have secret accounts with different seeds, *without* risk= ing user funds getting lost - a much more likely scenario - due to mistyped passwords. In any case, even if you were to do this type of design, a much better idea= is to use a checksum by default to reject invalid passwords, while having an advanced-use-only option to override that checksum. The virtual file encryp= tion filesystem encfs does exactly this with its --anykey flag. This allows adva= nced users to do their thing, while protecting the majority of users for whome t= his feature is dangerous. --=20 https://petertodd.org 'peter'[:-1]@petertodd.org --+QahgC5+KEYLbs62 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- iQEcBAEBCAAGBQJaVA7CAAoJECSBQD2l8JH7QvYH/27q6znMSZCnR7HlHrOMSLTk cR42uFegAWISOSXtIxZdInmQ+vz/okKzkcJ9DlaVVwxUDKcxlGu5810tgTP8YSag Q0ggzPHIv/VRP3+fXZiu1D+beUkmUXLtslnjqII4hON3Vrt0HB5LIgqK6atGjwtq DMa2C8l4J5Z5dh3ve5gzA9PElCfIkv+AJnJUipAlCMzjRG8JEF6uKxAUk97NYp0I xRkK/X21WNbdSttVk0ADspzR6iBp1jI2ojaSmoMYDBt0pDbeuy9sowHzkqelRjTJ acYK5fJbXBiTL6erzhsesAQ/D10a/XibzySj95IkT54adesDNm+lm13tlQLH0GQ= =mnaQ -----END PGP SIGNATURE----- --+QahgC5+KEYLbs62--