Verification
DIDs: Decentralized Identifiers in a DPP
What W3C Decentralized Identifiers are, how they are used in a Digital Product Passport and how they differ from GS1 or IEC 61406 identities.
A DID (Decentralized Identifier) is an identity that can be verified without depending on a central registration authority. It is a W3C standard and one of the product identifier schemes EN 18219 accepts.
How it works
A DID takes the form did:method:identifier. Resolving it returns a DID document containing public keys and service endpoints. A party verifying a signature takes the key from that document.
The critical property: verification does not require querying the issuing organisation online, which makes independent verification possible along a supply chain. See verifiable credentials.
Where it is used in a DPP
| Use | Value |
|---|---|
| Operator identity | Makes signature ownership independently verifiable |
| Issuer identity | Authenticity of whoever issued a certificate |
| Role attestation | Proof of roles such as recycler or repairer |
| Product identity | Possible, but GS1 and IEC 61406 are more common in practice |
Compared with GS1 and IEC 61406
A DID's advantage is decentralisation; its disadvantage is ecosystem maturity. For a manufacturer selling into retail, a GTIN-based Digital Link remains the most practical choice. DIDs add value in VC-native ecosystems and at the operator identity layer.
See EN 18219 unique identifiers and GS1 Digital Link.
The UNTP connection
UNECE's UNTP defines all its components as VCs and uses DIDs at the identity layer, an approach that stands out in cross-border trade scenarios. See UNTP.
Practical advice
Treat DIDs today as an architectural option, not a requirement:
- Choose an established scheme for product identity (GTIN or IEC 61406).
- Abstract the signing and verification layer so it can move to DID-based identities later.
- Follow your customer ecosystem if it mandates a particular approach.
Frequently asked questions
Do I have to use DIDs?
No. EN 18219 permits several schemes, and DIDs are one of them.
Do DIDs require blockchain?
Some DID methods use distributed ledgers, but web-based methods such as did:web do not.
Will consumers see a DID?
No. A consumer scans a QR and a page opens; DIDs sit in the infrastructure layer.
