Re: [TLS] draft-ietf-tls-esni feedback

Rob Sayre <sayrer@gmail.com> Wed, 23 October 2019 02:06 UTC

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From: Rob Sayre <sayrer@gmail.com>
Date: Tue, 22 Oct 2019 19:05:55 -0700
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To: Stephen Farrell <stephen.farrell@cs.tcd.ie>
Cc: "Salz, Rich" <rsalz@akamai.com>, "TLS@ietf.org" <tls@ietf.org>
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Subject: Re: [TLS] draft-ietf-tls-esni feedback
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On Tue, Oct 22, 2019 at 6:30 PM Stephen Farrell <stephen.farrell@cs.tcd.ie>;
wrote:

>
> So, at minimum, that'd mean s/32/128/ in my quoted text
> above, and likely more. (Plus, of course, doing the kind
> of due-diligence that lead to [1].)
>

Or, maybe, start at 256. :)

Low numbers might encounter all sorts of well-known cryptographic problems,
and varying the padding of the domain name with any granularity would tend
to narrow the search space for an attacker.

I'm not an expert in these matters, though.

thanks,
Rob