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Re: [CFRG] Comment on draft-irtf-cfrg-aead-limits-01

Stephen Farrell <stephen.farrell@cs.tcd.ie> Tue, 17 November 2020 00:27 UTC

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To: Eric Rescorla <ekr@rtfm.com>
Cc: CFRG <cfrg@irtf.org>
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From: Stephen Farrell <stephen.farrell@cs.tcd.ie>
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Date: Tue, 17 Nov 2020 00:27:35 +0000
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Subject: Re: [CFRG] Comment on draft-irtf-cfrg-aead-limits-01
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On 17/11/2020 00:19, Eric Rescorla wrote:
> I'm not following you here. This draft is about the lifetime of symmetric
> keys, which you can automate.

"Can" - sure. But while I'm open to correction, I believe
lots of small embedded systems using TLS and the like, and
maybe still cookie and/or token generating chunks of code,
do not.

With TLS or similar, at the point where the developer's
code has decided it's time to re-key, then the HOWTO is
automated. But the decision to do the re-key isn't.

With cookies and tokens, doing the re-key is a local
matter, (and pretty obvious), but still has to be decided
upon.

Again, that might be better not in this draft but I think
it may be a bit of text we don't yet have.

Cheers,
S.

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