DID Method

A DID method is to a DID what a URI scheme is to a URI. http:// and mailto: are both URIs, but what comes after the colon means something completely different in each, one names a web resource, the other an email address. A DID method plays the same role for DIDs: did:key:..., did:web:..., and did:solidus:... are all valid DIDs, but each method defines its own rules for how an identifier under it gets created, looked up, updated, and permanently deactivated.

A method is defined by a method specification: a document precise enough that an independent developer, with no contact with the method's authors, could write a working resolver for it from the text alone. Well-known examples: did:key (derived directly from a public key, no network involved), did:web (backed by a domain's HTTPS certificate and a .well-known file), and did:ion (backed by Bitcoin via the Sidetree protocol).

Where it comes from

The method-extension mechanism itself is part of W3C DID Core (see the DID entry). The registry tracking who has authored which method (the DID Specification Registries) lives at github.com/w3c/did-extensions and is open to anyone who writes a conformant spec and gets it merged. Solidus did not design this mechanism; we used it to register one method of our own.

Solidus status

Shipped. Solidus authored a single method, did:solidus, and it is registered in that list, see the did:solidus entry for the full detail, including the exact phrasing rule that keeps "registered" from drifting into "standardized" or "endorsed."

Proof you can run yourself: browse github.com/w3c/did-extensions/tree/main/methods directly, every registered method's spec file is public, solidus.json included, no account required.