[COSE] IANA registry for COSE Alg parameter

[Francesca Palombini <[e-mail]>]

Hi,

Following up on a discussion with Jim at IETF105, and discussion with my co-authors: both EDHOC (https://tools.ietf.org/html/draft-selander-ace-cose-ecdhe-14 ) and OSCORE Groupcomm (https://tools.ietf.org/html/draft-ietf-core-oscore-groupcomm-05 ) would benefit from a standardized way of getting the CBOR format (and optionally possible values) of the parameters associated to a COSE Algorithm. COSE does not currently specify that, it does have some of this info for COSE Key (depending on the key type), but we would really rather have a simple way to get that information from the algorithm directly. That means for example, specify the CBOR encoding of the parameter “curve” for  EdDSA.

As we first needed it in OSCORE Groupcomm, we have some proposed text for a IANA registry that could be used: https://tools.ietf.org/html/draft-ietf-core-oscore-groupcomm-05#section-9.1 . Since this is more general and we need this in other documents as well (EDHOC), we think it would make more sense to add this to one of the existing COSE specifications (draft-ietf-cose-rfc8152bis-algs?) or draft a new COSE document covering this.

We would ask the WG to consider adding such an IANA registry, and would like your opinion on where better to have this.

Thanks,
Francesca