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Re: [Trans] Angle brackets in the PRIVATE option (Ticket #1)

Rob Stradling <rob.stradling@comodo.com> Tue, 01 April 2014 20:26 UTC

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Date: Tue, 01 Apr 2014 21:26:32 +0100
From: Rob Stradling <rob.stradling@comodo.com>
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To: Gervase Markham <gerv@mozilla.org>, Peter Bowen <pzbowen@gmail.com>, Rick Andrews <Rick_Andrews@symantec.com>
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Subject: Re: [Trans] Angle brackets in the PRIVATE option (Ticket #1)
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On 01/04/14 14:54, Gervase Markham wrote:
> On 31/03/14 12:10, Rob Stradling wrote:
>> How long would it take an attacker to perform a dictionary attack to
>> discover that "6f993bb2" corresponds to "mail.corp" ?
>
> If only some correlation is desired, then you could just use e.g. the
> last two digits of the checksum. This allows a correct match when in
> possession of the correct cert, but also one can imagine many
> non-existent certs which would also match.

Hi Gerv.  I don't think this is desirable.

Only the domain owner needs to know what the unmasked subdomains are, 
and they can do this by simply looking at the corresponding Certificate.

-- 
Rob Stradling
Senior Research & Development Scientist
COMODO - Creating Trust Online

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