Re: [core] Review of draft-fz-core-coap-pm-03

Giuseppe Fioccola <> Mon, 13 March 2023 18:15 UTC

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From: Giuseppe Fioccola <>
To: Giuseppe Fioccola <>, Christian Amsüss <>, Marco Tiloca <>
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Thread-Topic: [core] Review of draft-fz-core-coap-pm-03
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Date: Mon, 13 Mar 2023 18:15:33 +0000
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Subject: Re: [core] Review of draft-fz-core-coap-pm-03
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Dear All,
Please note that we just submitted the new version of draft-fz-core-coap-pm in order to address the comments received during the interim meeting and on the mailing list.

Feedback and suggestions are always welcome.


(on behalf of the coauthors)

-----Original Message-----
From: core <> On Behalf Of Giuseppe Fioccola
Sent: Friday, March 10, 2023 4:34 PM
To: Christian Amsüss <>; Marco Tiloca <>
Subject: Re: [core] Review of draft-fz-core-coap-pm-03

Hi Christian,
Please see inline [GF]



-----Original Message-----
From: core <> On Behalf Of Christian Amsüss
Sent: Friday, March 10, 2023 4:19 PM
To: Marco Tiloca <>
Subject: Re: [core] Review of draft-fz-core-coap-pm-03


just one remark on what I noticed skimming:

On Sun, Feb 26, 2023 at 08:30:11PM +0100, Marco Tiloca wrote:
> * When using OSCORE, having the PM option as inner or outer does not 
> have to be mutually exclusive. That is, measurements can be performed 
> both at the ends, and in the individual hops, by having the option both outer and inner.
>    However, if the PM option is used (also) as an outer option, 
> shouldn't the outer option also be (at least) integrity-protected, to 
> be reliably processed by the intended consumer? This would require 
> using also DTLS hop-by-hop, or an (additional) OSCORE association with 
> an intermediary (see draft-tiloca-core-oscore-capable-proxies).

I don't think that option should be Class-I. The option is hop-by-hop now, and may be legitimately terminated at proxies. If it were Class-I, a proxy's operation would make the requests fail.

[GF]: Yes, in case of collaborating proxies, the option is terminated at proxies and Class E is ok. But, in case of non-collaborating and non-caching proxies an implementation may consider the option as Safe-to-Forward in order to implement measurements. In this corner case, Class-I can be considered to enable hop-by-hop.

If an OSCORE endpoint sends both outer and inner, the inner is for measuring the connection to the E2E peer, and the outer is for measuring the connection to next hop proxy.

[GF]: Yes


To use raw power is to make yourself infinitely vulnerable to greater powers.
  -- Bene Gesserit axiom

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