Too strict definition of Claim format designations

[babisRoutis]

Presentation Exchange contains a section about the contents of an attribute named format which can be found either as a top-level element of presentation definition or with an input_descriptor.

This format is a JSON object having as attribute names claim formats coming by a controlled registry. In turn, each of these nested claim formats may point to another JSON Object which contains either an array alg or proof_type as defined in the relevant json schema.

Library reflects in its types the above rules, strictly. There are problems with this strictness:

OpenId4VP draft 20 uses claim formats that are not (yet) registered to the aforementioned Presentation Exchange controlled registry. In particular:

• jwt_vc_json & jwt_vp_json in A.1.1
• ac_vc & ac_vp in A.2
• mso_mdoc in A.3
• sd+jwt-vc to be added for sd-jwt-vc (PR). This doesn't only add a new value but redefines the contents of the relevant JSON to contain two arrays : sd-jwt_alg_values & kb-jwt_alg_values

So library-wise there are two options:

• Implement just the registered claims formats (current approach)

• Relax the format object accepting the fact that neither all keys are registered nor the contents of their value

  The first is too restrictive, I guess. Perhaps we should go with the 2nd option.

[vafeini]

Indeed option 2 is a better way forward. At least until the set of formats is stabilized library should be more relaxed.