From: "Odinn Cyberguerrilla" <odinn.cyberguerrilla@riseup•net>
To: "Peter Todd" <pete@petertodd•org>
Cc: bitcoin-development@lists•sourceforge.net
Subject: Re: [Bitcoin-development] New side channel attack that can recover Bitcoin keys
Date: Wed, 5 Mar 2014 23:02:51 -0800 [thread overview]
Message-ID: <2f64c4dbc080d876a68e4b12b31ad612.squirrel@fulvetta.riseup.net> (raw)
In-Reply-To: <20140305193910.GA24917@tilt>
One wonders also re. bitmessage, though that may not be relevant to this
particular list.
> On Wed, Mar 05, 2014 at 11:21:52AM -0500, Kevin wrote:
>> On 3/5/2014 7:49 AM, Mike Hearn wrote:
>> >A new practical technique has been published that can recover
>> >secp256k1 private keys after observing OpenSSL calculate as little
>> >as 200 signatures:
>>
>> How can we patch this issue?
>
> If you're following good practices you're not particularly vulneable to
> it, if at all, even if you make use of shared hosting. First of all you
> shouldn't be re-using addresses, which means you won't be passing that
> ~200 sig threshold.
>
> More important though is you shouldn't be using single factor Bitcoin
> addresses. Use n-of-m multisig instead and architect your system such
> that that every transaction that happens in your service has to be
> authorized by both the "online" server(s) that host your website as well
> as a second "hardened" server with an extremely limited interface
> between it and the online server. The hardened second factor *should*
> use a separate codebase, ideally even a second language, to authenticate
> actions that withdraw funds or generate new addresses based on data
> given to it by the online server. In the best case your customers are
> PGP-signing requests so you can verify their intent independently and
> cryptographically on both servers. Mircea Popescu's MPEx exchange is an
> example of this model, although I don't think they're doing any multisig
> stuff. Failing that you can at least use the second server to do things
> like limit losses by flagging higher-than-expected withdrawl volumes and
> unusual events.
>
> Since this second-factor server only deals with business logic - not the
> website - you can certainly find a secure hosting arrangement for it
> with physical control. I recommend you stick the machine in your
> apartment and use tor + hidden services to connect to it from your VM
> instances.
>
> Note too that even if all you're doing is accepting Bitcoins from
> customers, perhaps in exchange for goods, all of the above *still*
> applies modulo the fact that the payment protocol is very incomplete.
>
>
> With P2SH (finally!) supported in all the major Bitcoin wallets there
> simply is no excuse not to have such an architecture other than lazyness
> and transaction fees; if you fall into the latter category you're
> business may very well be wiped out anyway by increased fees.
>
> --
> 'peter'[:-1]@petertodd.org
> 000000000000000f9102d27cfd61ea9e8bb324593593ca3ce6ba53153ff251b3
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next prev parent reply other threads:[~2014-03-06 7:03 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-05 12:49 Mike Hearn
2014-03-05 12:56 ` Pieter Wuille
2014-03-05 13:18 ` Jean-Paul Kogelman
2014-03-05 14:04 ` Pieter Wuille
2014-03-05 16:21 ` Kevin
2014-03-05 19:39 ` Peter Todd
2014-03-05 19:51 ` Gregory Maxwell
2014-03-05 20:32 ` Peter Todd
2014-03-05 20:54 ` Gregory Maxwell
2014-03-12 9:44 ` Peter Todd
2014-03-05 22:17 ` James Hartig
2014-03-05 22:26 ` Eric Lombrozo
2014-03-06 7:02 ` Odinn Cyberguerrilla [this message]
2014-03-08 19:34 ` Luke-Jr
2014-03-09 1:57 ` Gregory Maxwell
2014-03-05 21:31 ` Eric Lombrozo
2014-03-05 21:44 ` Gregory Maxwell
2014-03-05 22:14 ` Eric Lombrozo
2014-03-05 22:25 ` Gregory Maxwell
2014-03-06 8:38 ` Mike Hearn
2014-03-06 10:00 ` Natanael
2014-03-25 13:39 ` Troy Benjegerdes
2014-03-25 13:50 ` Gavin Andresen
2014-03-08 19:29 ` Gustav Simonsson
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