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[76.111.96.126]) by mx.google.com with ESMTPSA id v61sm37615229yhp.24.2013.08.05.09.47.40 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 05 Aug 2013 09:47:41 -0700 (PDT) Message-ID: <51FFD722.5090403@gmail.com> Date: Mon, 05 Aug 2013 12:47:30 -0400 From: Alan Reiner User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130620 Thunderbird/17.0.7 MIME-Version: 1.0 To: bitcoin-development@lists.sourceforge.net References: <51FFCA9A.6010208@gmail.com> In-Reply-To: <51FFCA9A.6010208@gmail.com> X-Enigmail-Version: 1.5.2 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Spam-Score: -1.6 (-) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (etotheipi[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature X-Headers-End: 1V6Nwh-0000FI-Q3 Subject: Re: [Bitcoin-development] Safe auto-updating X-BeenThere: bitcoin-development@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 05 Aug 2013 16:47:49 -0000 Indeed. You can hardcode a "distributor" public key in the software, and client software will only trust signed data from that key. Of course, the private key for that data is not kept on the server distributing the signed checksums. Ideally it would be kept offline, and the couple-times-per-year that you actually execute an upgrade, you sign the new checksums offline and upload the signed checksum to the distribution server. Then even if the server is compromised, the client-side software will not accept a bogus checksum because it won't bear the right signature. If you do this, it would be good to also have some kind of revocation process that can be used in the event of the offline key being compromised. You won't be able to "switch" keys, as that would defeat the purpose (the attacker who compromises the offline key could just issue a replacement with his own). Instead, it would be an irreversible broadcast that would force clients to start rejecting updates from that key. If the key is compromised (and find out), you broadcast the revocation and the users will stop auto-updating, and be given a warning that they should manually upgrade the software through trusted channels. It's not failproof, but it's a decent way to minimize damage if you discover compromise early enough. -Alan On 08/05/2013 11:54 AM, Daniel F wrote: > If you want package authentication, you should at least throw in some > digital signing, not just a checksum. With a compromised host, both the > checksum and binaries can be changed undetectably, but if there's a > signature made by a key that is not kept on the host, there's no way to > fake a valid binary. > > There may be other issues people would want to bring up, but surely just > a checksum is not sufficient. > > on 08/05/2013 10:39 AM Wendell said the following: >> For usability purposes, we at Hive would like to have an >> auto-updater > in our wallet app. >> What is a safe way to do this? I understand that Bitcoin-QT lacks >> such > an updater for security reasons... Has been thought out in more detail > since that decision was made? >> We have been toying around with the idea of placing one server >> behind > a Tor hidden service, whose only function is to output a checksum of the > update package. The theory is that if it is well-secured, it will at > least be immune to tampering at the physical hosting level. >> Any thoughts or advice about any of this? >> -wendell >> >> grabhive.com | twitter.com/grabhive | gpg: 6C0C9411 >> >> >> >> ------------------------------------------------------------------------------ >> Get your SQL database under version control now! >> Version control is standard for application code, but databases havent >> caught up. So what steps can you take to put your SQL databases under >> version control? Why should you start doing it? Read more to find out. >> http://pubads.g.doubleclick.net/gampad/clk?id=49501711&iu=/4140/ostg.clktrk >> >> >> >> _______________________________________________ >> Bitcoin-development mailing list >> Bitcoin-development@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/bitcoin-development >> > > ------------------------------------------------------------------------------ > Get your SQL database under version control now! > Version control is standard for application code, but databases havent > caught up. So what steps can you take to put your SQL databases under > version control? Why should you start doing it? Read more to find out. > http://pubads.g.doubleclick.net/gampad/clk?id=49501711&iu=/4140/ostg.clktrk > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development