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Re: Proposed Statement on "HTTPS everywhere for the IETF"

Ted Lemon <Ted.Lemon@nominum.com> Thu, 04 June 2015 17:39 UTC

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From: Ted Lemon <Ted.Lemon@nominum.com>
Subject: Re: Proposed Statement on "HTTPS everywhere for the IETF"
Date: Thu, 04 Jun 2015 13:39:22 -0400
To: Tony Hain <alh-ietf@tndh.net>
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Cc: Joe Hildebrand <hildjj@cursive.net>, "<ietf@ietf.org>" <ietf@ietf.org>
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On Jun 4, 2015, at 1:20 PM, Tony Hain <alh-ietf@tndh.net> wrote:
> The set of possible requests is inherently public information. Pairing a
> request length with the possible set of return lengths seriously reduces the
> set, and that is before you factor in who is being watched and what they
> might be looking for.

No.   RFC numbers are all the same length, except for the very early ones.   Plus, the headers in a request vary enough that it's unlikely that this attack would be as easy as you say; furthermore, https used for privacy is most effective at preventing passive attacks, and in this case the expense of doing the sort of analysis you are describing would be significant.

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