[Rats] Iotdir early review of draft-ietf-rats-msg-wrap-04

[Mohit Sethi via Datatracker <[e-mail]>]

Reviewer: Mohit Sethi
Review result: Almost Ready

I am the assigned IoT-Directorate reviewer for this draft.

Review result: Almost ready.

Some minor comments:

* Section 4: Perhaps expand what is CoRIM and add a reference to
https://datatracker.ietf.org/doc/html/draft-ietf-rats-corim-04

* Section 5 and 5.1: It would be helpful for readers if a short use-case
explaining when CMW would be transported in CRLs could be provided. While I can
guess why a CMW would be in a CSR, I could not immediately understand when a
CMW would be part of a CRL. Similarly, it would be helpful to explain where and
how the ASN.1 module will be used. I assume it is relevant for cases where a
certificate containing a CMW extension is passed around?

* Section 5.2: I wonder about the consequences of having two different CMW
specifications: one by the Trusted Computing Group (TCG) and the other in this
draft. I downloaded the TCG specification and found a reference to this draft.
Would it be possible for future versions of the TCG specification to reuse this
draft rather than creating a subset? Also, this draft states that the "CMW
extension" "MUST NOT be marked critical," whereas the TCG specification states
that the "tcg-dice-conceptual-message-wrapper extension criticality flag SHOULD
be marked critical." In summary, I wonder if these specifications can somehow
be synchronized.

Section 7: Please expand UCCS on first use: unprotected CWT Claims Sets (UCCS).

Note: I haven't verified the CDDL, CBOR, and JSON for correctness via tooling,
but they looked fine while reading.