Accessibility Self-Review Questionnaire for Verifiable Credential Barcodes v1.0

[wes-smith]

The Verifiable Credential Barcodes specification defines mechanisms for embedding Verifiable Credentials in optical barcodes such as QR codes and PDF417 barcodes. It defines no user interface, no markup language, and no author-facing UI components, so most user-interface criteria do not apply directly.

We believe that this specification, in general, does not create accessibility concerns, but are curious to know if we have overlooked some aspect of how this technology will be used that will create accessibility issues.

The following self-review question categories were analyzed and resulted in the following answers:

• While barcodes are visually rendered, the specification itself DOES NOT define presentation, layout, or rendering behavior for barcodes that contain Verifiable Credentials. The specifics of those barcodes are inherited from the optical barcode technology and the use case.
• The technologies DO NOT provide author control over color
• The technologies DO NOT provide features to accept user input
• The technologies DO NOT provide user interaction features
• The technologies DO define document semantics - the header string "VC1-" in a QR code indicates the location of an encoded Verifiable Credential.
• The technologies DO NOT provide time-based visual media
• The technologies DO NOT provide audio
• The technologies DO NOT allow time limits
• The technologies DO allow text content
  • Verifiable Credential Barcodes can include human-readable (once decoded and displayed) text properties as in the Verifiable Credentials Data Model . That mechanism supports language tagging and base direction, enabling the text to be presented accessibly.
• The technologies DO create objects that don't have an inherent text representation
  • The contents of barcodes may or may not be text-based. Barcodes themselves are not inherently textual. CBOR-LD binary payloads are not textual. We would welcome feedback from reviewers on to what extent this accessibility concern applies to the specification.
• The technologies DO NOT provide content fallback mechanisms, whether text or other formats
• The technologies DO NOT provide visual graphics
  • Barcode rendering, while strongly related to the technologies in the specification, is out of scope.
• The technologies DO provide internationalization support
  • The Verifiable Credentials Data Model permits language-tagged and direction-aware string values, so text can be localized and made accessible.
  • Date values, expressed via validFrom and validUntil follow the Validity Period of the Verifiable Credentials Data Model, where the date can be localized and made accessible.
• The technologies DO NOT define accessible alternative features
• The technologies DO NOT provide content directly for end-users
  • The specification defines mechanisms to express credentials as optically readable data, intended to be consumed by verifiers rather than end users.
• The technologies DO NOT define an API
• The technologies DO NOT define a transmission protocol