From: Wendell <w@grabhive•com>
To: Peter Todd <pete@petertodd•org>
Cc: Bitcoin Dev <bitcoin-development@lists•sourceforge.net>
Subject: Re: [Bitcoin-development] Safe auto-updating
Date: Wed, 7 Aug 2013 06:32:08 +0200 [thread overview]
Message-ID: <4E4E5921-E8BF-4274-A062-EF1FBC331C95@grabhive.com> (raw)
In-Reply-To: <09169cb2-cc59-4261-84e9-0769ec72af6b@email.android.com>
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That multisignature/blockchain commitment idea seems really solid, Peter.
Thanks very much indeed everyone, this is all very helpful. Much to research and think about.
Interestingly, a thread is presently raging on liberationtech about Tor Browser Bundle, and the subject of automatic updates has come up. Gregory Maxwell responded thusly (cross-posting for completeness):
> _please_ don't deploy automatic updates in a sensitive environment
> like this without at least quorum signatures (like gitian downloader)
> and timed quarantine with negative signatures (harder to make strong
> absent a jamming proof network).
-wendell
grabhive.com | twitter.com/grabhive | gpg: 6C0C9411
On Aug 5, 2013, at 7:49 PM, Peter Todd wrote:
> Gregory Maxwell had some good ideas along these lines at the san jose conference. Extending gitian with these kinds of features would be a good approach.
>
> But I think its worth thinking about attack models. A huge danger with auto-updating is that it is easy to target individuals; if I leave auto-updates on I am essentially trusting the developers capable of signing an update not to specifically try to attack me in the future, a much more risky thing to do than simply trusting them not to release a malicious release.
>
> Sure you can try to implement anonymous downloads and similar mechanisms, but they all tend to be fragile with regard to deanonymization attacks.
>
> A better way is to ensure that the act of making a release available for download must be public, even if you can control what binaries are made available to a particular target. You can do this by putting a commitment in the blockchain itself. Each person on the signing list creates a transaction with a special form from a specific pubkey that commits to the digest of the binaries, and the auto-update code refuses to update unless it sees that special transaction with a sufficient number of confirmations. The developers now can't make a special release for a specific target without letting the world know they did so, even under coercion.
>
> They developers could of course still make a release with code inside targeting a specific individual, but in theory at least the public can check if their builds are reproducible, and start asking questions why not?
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next prev parent reply other threads:[~2013-08-07 7:48 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-05 14:39 Wendell
2013-08-05 15:54 ` Daniel F
2013-08-05 16:47 ` Alan Reiner
2013-08-05 17:14 ` Jim
2013-08-05 17:49 ` Peter Todd
2013-08-07 4:32 ` Wendell [this message]
2013-08-07 8:41 ` Mike Hearn
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