Re: [Ace] EDHOC standardization

Michael Richardson <mcr+ietf@sandelman.ca> Fri, 02 November 2018 22:52 UTC

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From: Michael Richardson <mcr+ietf@sandelman.ca>
To: John Mattsson <john.mattsson@ericsson.com>
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Comments: In-reply-to John Mattsson <john.mattsson@ericsson.com> message dated "Fri, 02 Nov 2018 12:31:16 +0000."
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Date: Sat, 03 Nov 2018 05:51:55 +0700
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Subject: Re: [Ace] EDHOC standardization
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John Mattsson <john.mattsson@ericsson.com>; wrote:
    > of negotiation is still needed. The current plan for the next version
    > is to introduce cipher suites and to let the cipher suite with value 0
    > indicate that algorithms have been negotiated out-of-band.

I agree with the idea that some common default should be very easy to
refer to, but I don't like the idea that the gateway has to remember what
the out-of-band "default" is on a per-device basis.  I would say that we need
at least 0/1, so that we can say that it's the current vs the "new" default.

If you consider the case where the sensor is on very low bandwidth
connection (I would say LoRaWAN, but I am not well qualified in that space).
The sensor gets visited every two or three years by a technician (if only to
make sure that the sensor is still where it is supposed to be).  While there
new firmware updates are applied, and as a result the algorithm defaults are
updated.  During the cycle, some devices are updated and some are still old.

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