Introduction

Data models are abstract representations that show how data is structured, organised and related within an information system. They provide a conceptual framework for understanding data, allowing effective design, implementation and management of information systems. For structuring data for Verifiable Credentials, EBSI is committed to using the standards established in the W3C Verifiable Credentials Data Model (VCDM), as they are permissionless and decentralised.

The current version is VCDM 1.1 with VCDM 2.0 planned for future implementations. Details on the changes associated with the updated model can be found on the following page.

UPDATES AND VERSION

Any change in the JSON Schema that does not relate to JSON Schema annotations is considered a breaking change and requires the registration of a new schema version.

Schema ID

The schema ID must be computed as follows:

1. Bundle the JSON Schema. Please see here.
2. Remove JSON Schema annotations (such as description, title, examples) and comments ($comment) from the schema. Thus, changing a description will not change the schema ID.
3. Canonicalise the bundled JSON Schema using JSON Canonicalization Schema (JCS).
4. Apply the SHA256 hashing algorithm to the canonicalised document.
5. Encode the resulting hash using multi-base encoding, with the default encoding of base58btc.

The Trusted Schemas Registry API computes the schema ID upon schema registration.

JSON Schema specification

All schemas must support the JSON Schema 2020-12 specification as most JSON Schema validators and parsers offer support for this version.