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Re: [TLS] Addressing cookie theft (think BEAST) with channel bound cookies using TLS session IDs

Nico Williams <nico@cryptonector.com> Thu, 29 September 2011 14:22 UTC

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Date: Thu, 29 Sep 2011 09:25:20 -0500
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From: Nico Williams <nico@cryptonector.com>
To: Florian Weimer <fweimer@bfk.de>
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Subject: Re: [TLS] Addressing cookie theft (think BEAST) with channel bound cookies using TLS session IDs
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On Thu, Sep 29, 2011 at 5:52 AM, Florian Weimer <fweimer@bfk.de> wrote:
> * Nico Williams:
>
>> A while back Dirk Balfanz proposed something he called "origin bound
>> certificates" and "channel bound cookies".  A lighter-weight
>> alternative (i.e., involving no protocol changes) would be nice.
>> Mine: use TLS session IDs as the channel binding.
>
> If we're interested in working around the cookie issue (as opposed to
> fixing the protocol issue), I think it would be simpler to include a
> random prefix in the cookie, ignored by the server, and the server would
> change the prefix every few requests.

I don't see how that would stop BEAST.  And, in any case, would
require changes to clients and servers both, which makes it much
harder to deploy.

Nico
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