VC schema: clarify optionality of parameters

[bluesteens]

Steering summary:

The current OCI Credential Schema leaves room for interpretation in its statement of Verifiable Presentation metadata requirements. Suggest to rework the spec to introduce clarity.

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Detailed Description:

The OCI Credential Schema spec 7.12 Verifiable Presentation of DSCSA-ATP-Credential lists several metadata fields and references the original W3C VC Data Model spec.

Issue:

OCI does not explicitly state whether the listed items are mandatory or optional. The W3C spec states or may be interpreted as stating that at least some of the items may be optional. Wallet implementers may use different interpretations, which could hamper interoperability through differing implementations.

Suggestion:

Clarify in the OCI spec which parameters are mandatory/optional.

Note:

Look at Credential (7.1) and Credential Presentation (7.12) Metadata. related ticket: https://github.com/Open-Credentialing-Initiative/Digital-Wallet-Conformance-Criteria/issues/58

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Triage:

• [x] Is Issue appropriate for OCI Architecture
• [x] Assign Size
• [x] Assign Priority
• [x] Assign Label (if needed)
• [x] OCI affected Artifacts Identified
• [ ] Assign Triage - Artifact Version Target (v x.x.x Milestone)
• [ ] Assign Triage - Interop Profile Version Target (v x.x.x Milestone)
• [ ] Create sub-project (if needed)

Affected Parties (help determine Sunrise/Sunset):

• [ ] Trading Partners
• [ ] Issuers
• [x] Wallet Solutions
• [ ] PI Verification Solutions

Affected OCI Artifact

• [x] Schema Document
• [ ] Identity Schema
• [ ] ATP Schema
• [ ] Issuer Conformance Criteria
• [ ] Wallet Conformance Criteria
• [ ] VRS Solution Conformance Criteria
• [ ] Wallet API Specification
• [ ] Governance Document
• [ ] Conformance Program
• [ ] OCI Website
• [ ] Internal Process

Change Category (Guides Steering Review)

- Steering/Industry Review

• [ ] Business-Level (May affect business operations)
• [ ] OCI Governance, Policy or website feature

- Steering/Industry Notification

• [x] Technical-Level (Does not affect business operations)
• [ ] OCI Internal Process or Infrastructure

Communication

• [ ] Website
• [ ] Newsletter
• [ ] email:
• [ ] Other:

[bluesteens]

also consider specifying the exact W3C doc version in the confo criteria

[bluesteens]

also consider whether para 7.1 needs to have requirements stated more explicitly: https://open-credentialing-initiative.github.io/schemas/specification/v1.0.0/#dscsa-atp-credential-metadata