CoRIM needs to support counter signatures

[yogeshbdeshpande]

The base CoRIM specification refers to signer and signer details via signer-map.

However use cases coming from real world indicates that CoRIM should support multiple signers.

One such use case is the case of counter signatures, especially when CoRIM is blessed by a trusted auditor.

Specification should be enhanced to add the required text highlighting multiple signature support + CDDL needs to be revisited for any changes to support this enhancement

[nedmsmith]

is it more complex than adding support for COSE_Sign?
e.g.:

signed-corim = #6.18(COSE-Sign1-corim)

becomes:

signed-corim = #6.18(COSE-Sign1-corim) / #6.19(COSE_Countersignature)

[thomas-fossati]

I am not sure there's anything to do here: RFC9338 countersignatures can already be added to the COSE_Sign1 message that wraps the CoRIM tag