Decentralized identifiers (DIDs) are a new type of identifier that enables verifiable, decentralized digital identities. A DID identifies any subject (e.g., a person, organization, thing, data model, abstract entity, etc.) that the controller of the DID decides that it identifies. DIDs are URIs that associate a DID subject with a DID document allowing trustable interactions associated with that subject.
To learn more about DIDs and why they're useful: