Verifiable Credentials JSON Schema Specification

The Verifiable Credentials JSON Schema Specification is a standard that defines how to use JSON Schema to validate the structure and content of Verifiable Credentials. It provides a mechanism for creating machine-readable schemas that can enforce data formats, required fields, and value constraints within credentials. This specification is particularly important for ensuring consistency and interoperability in credential issuance and verification processes.

The standard supports two primary implementation approaches:

• Direct JSON Schema usage through the JsonSchema type
• Schema representation as a verifiable credential using the JsonSchemaCredential type

Key technical aspects include:

1. Purpose and Scope:

• Enables structured validation of Verifiable Credentials data
• Supports schema validation for entire credentials or specific properties
• Provides mechanisms for content integrity protection
• Allows for schema versioning and composition

2. Key Technical Specifications:

• Requires support for JSON Schema 2020-12 specification
• Uses $id and $schema keywords for schema identification
• Supports both JSON and YAML representations
• Implements digestSRI for schema integrity verification

3. Implementation Requirements:

• Must support specified JSON Schema versions
• Must implement schema resolution processes
• Must handle three validation outcomes:
  • Success
  • Failure
  • Indeterminate

4. Security Considerations:

• Content integrity protection through digital signatures
• Schema authenticity verification
• Protection against issuer impersonation
• Secure schema resolution and caching

5. Interoperability Features:

• Standardized media types for transmission
  • application/schema+json
  • application/vc+jwt
  • application/vc+sd-jwt
• Support for multiple schema composition
• Cross-platform schema validation

6. Current Adoption Status:

   The specification is currently at W3C Candidate Recommendation Draft stage
   Requires at least two independent implementations for mandatory features
   Actively seeking implementation feedback

The standard is maintained by the Verifiable Credentials Working Group at the W3C and represents a critical component in the broader Verifiable Credentials ecosystem.