The Credential Schema is a document that is used to guarantee the structure, and by extension the semantics, of the set of claims comprising a Verifiable Credential. A shared Credential Schema allows all parties to reference data in a "known way".
A schema can be viewed from four perspectives: the author, issuer, verifier and holder.
- Author: An author creates a schema and registers it in Hypersign blockchain as to provide a blueprint for a Verifiable Credential, specifying the shape and format of the data in such a credential.
- Issuer: Issuers utilize schemas to provide structure and meaning to the data they issue as Verifiable Credentials. By using schemas, issuers contribute to a credentialing ecosystem that promotes the usage and adoption of data standards.
- Verifier: Verifiers processes a Verifiable Credentials and need to do so with knowledge of the terms and data the compromise the credentials. Credential Schemas aid a verifier in both requesting and processing credenetials that have been produced in a well-known format.
- Holder: Holders, or those who are the subject of credential issuance, can make sense of the data they control by evaluating it against a data schema. When data is requested from a holder which references a Credential Schema the holder has the capability to to present the data specifically requested by the verifier.
Note: Often, Issuer and Author of schema may be same.