Standards
DIDs & Verifiable Credentials
W3C Decentralized Identifiers (DIDs) and Verifiable Credentials (VCs) provide the trust layer for high-value DPP records. They are mandatory in Catena-X and recommended for EV batteries, aircraft parts and industrial goods.
DIDs in one paragraph
A DID is a URI that resolves to a DID Document containing public keys and service endpoints. The subject controls the keys, not a registry. Multiple DID methods exist (did:web, did:key, did:ebsi, …); did:web is the pragmatic default — the DID Document is hosted on your domain at a well-known path.
Verifiable Credentials in one paragraph
A VC is a signed assertion by an issuer about a subject: e.g., "Smelter S asserts that ingot I has embodied carbon X." The subject need not trust the issuer's infrastructure — only the issuer's key. Data in the DPP can be composed of many VCs from different tiers of the supply chain.
Choosing a DID method
| Method | When to use |
|---|---|
did:web | You control a stable domain and want low-ceremony adoption. |
did:ebsi | You are in the EBSI ecosystem (European Blockchain Services Infrastructure). |
did:key | Short-lived identifiers, ephemeral attestations. |
Practical advice
- Start with
did:web. Migrate only if a sector requires a ledger-anchored method. - Use JWT-based VCs — the tooling ecosystem is larger than JSON-LD proofs today.
- Rotate keys annually. Publish the revocation list.
- Keep a fallback identifier (GTIN or SGTIN) for retail scanning compatibility.