BREAKING: W3C Verifiable Credentials Get MAJOR Security Upgrade - Here's What's New!

• Added formal registration of six new media types with IANA for standardized identification of secured credentials and presentations
• Enhanced security requirements with explicit rejection of unsigned JWTs using "alg": "none" header
• Introduced comprehensive conformance classes for JWS, SD-JWT, and COSE implementations with clear MUST requirements
• Added detailed verification algorithms for each security method (JOSE, SD-JWT, COSE) with standardized outputs
• Improved key discovery mechanisms using header parameters (kid, iss, cnf) and controlled identifier documents
• Enhanced privacy considerations with specific guidance on selective disclosure usage
• Added accessibility requirements following WCAG 2.1 guidelines for cryptographic implementations
• Expanded examples with practical implementations for credentials, presentations, and data URIs

The W3C Verifiable Credentials Data Integrity specification establishes standardized cryptographic methods for securing Verifiable Credentials and Presentations using three main technologies: JOSE (JWS/JWT) for basic integrity and authenticity, SD-JWT for privacy-preserving selective disclosure, and COSE for efficient binary encoding in constrained environments. This Candidate Recommendation combines the W3C's standard data model with proven cryptographic standards through an "enveloping proof" approach, ensuring credentials remain authentic, tamper-proof, and privacy-preserving while enabling interoperability across different systems through registered media types and clear verification procedures.