DID Document v1.0 (deprecated)
The unified format is based on the Decentralized Identifiers (DIDs) v1.0 specification. DIDs are globally unique identifier in the form of URIs. The URI scheme includes a method name which corresponds to a standard method by which a DID Document can be resolved. This DID Document is a structured JSON-LD which captures each existing public key (regardless of X.509 or JWK format used) by the members of a trust network in a common format. It allows additional metadata (such as intended purpose and key identifiers) to be added to existing keys with changing the underlying keys themselves. It provides means to publish and cryptographically sign a master lists of keys recognized used by a trust network.
The unified format DID method selected is did:web, a method to retrieve DID Documents via existing web (https) infrastructure. The did:web identifiers have the form <DOMAIN NAME>:<PATH COMPONENT 1>:...: <PATH COMPONENT N>. Resolution is accomplished by https GET against the URL which is formed from this identifier by https://DOMAIN NAME/PATH COMPONENT 1/.../PATH COMPONENT N/did.json. For example did:web:example.com:my:path would resolve a DID Document from the URL https://example.com/my/path/did.json. Additional did methods may be supported in the future.
The DID Document itself should have:
- an ‘id’ field which is the DID itself and represents the DID Subject, in this case the trust list
- a list of public keys within the ‘verificationMethod’ field
- an optional signature via a ‘proof’ field
The verificationMethod array represents the individual signing keys associated with issuers within the entity represented by the DID Subject, an includes:
- an
idfield which is a DID URL composed of the DID for this DID Document and key ID as DID#key - controller of the public key, which can be current document (in case of publishing a key by a trust network member) or the source of the public key in case of an aggregator
- the public key JWK, including the key’s x509 and chain of trust to Root Certificate Authority
The DID Document itself can be signed with addition of a ‘proof’ block containing signature details and key used for verification.
For more information regarding the DID Document format for a Trust List specification, see WHO DDCC Trust List Specification documentation. For an example of a signed DID Document, see Appendix A of the documentation.