Credential Display logic (universal/deterministic)

[kayaelle]

Recommended techniques on ensuring a VC is displayed similarly across different apps and devices. (Embedded images, signed HTML, signed SVG, etc).

[dmitrizagidulin]

Proposed scope / discussion (from the VC Edu call on Apr 18, 2022).

Use cases:

• Issuers need to specify (or at least advise) to wallets, verifiers and other consumers of VCs, how to display those credentials. This can mean a static display (such as a PNG or a PDF), or a templated component (such as HTML or SVG).
• Both methods of specifying display logic need to be supported -- embedded in the VC, and linked to externally-stored logic.
• When linking to externally stored display spec, a digest hash SHOULD be included (for example, anchoredResource) to provide cryptographic binding between the VC and the display spec. (See issue [To Discuss] Image integrity #6 )
• The content-type of the display logic (png, html, pdf, etc) should be specified (so that the wallet knows how to display it).
• For purposes of brevity/storage savings, it would be preferable if the display logic was cross-platform (would appear the same on all sorts of devices). However, it may turn out that issuers may need to specify multiple sets of display specs that depend on device (see for example how this is handled for app icons, CSS/HTML pages, etc).

[kayaelle]

Email archive from @msporny re: paper for Reboot Web of Trust 11 paper topic rendering verifiable credentials: https://lists.w3.org/Archives/Public/public-credentials/2022Jul/0054.html