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

Stephen Farrell <stephen.farrell@cs.tcd.ie> Mon, 21 October 2019 19:48 UTC

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To: Eric Rescorla <ekr@rtfm.com>
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From: Stephen Farrell <stephen.farrell@cs.tcd.ie>
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Date: Mon, 21 Oct 2019 20:48:00 +0100
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Subject: Re: [TLS] draft-ietf-tls-esni feedback
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Hiya,

On 21/10/2019 20:29, Eric Rescorla wrote:

> The question is not the server, but the operator.

Sure, but the point holds though. If ESNIKeys are changed every
N seconds, and any new certificate is loaded during that time,
then the server operator can't tell the lengths that the CAs
might produce in future. So with the current design 260-always is
the only thing a server-operator (or really an ESNIKeys generator
who may be a slightly different entity) can rely on in general.

> Yes, but I do not believe that it obtained the consensus of the WG.

Not yet, that's true. OTOH, the 260 value wasn't decided on
the list either that I recall. However, I'm not objecting to
the current design for process reasons at all, I'm only critical
of it technically:-)

> Obviously, if the chairs call consensus on this point, we will change the
> draft.

Sure. We'll see where it lands. I remain hopeful a better
design will be the result.

S.