Decentralized Identifiers (DIDs) are an important innovation in the emerging blockchain-based / self-sovereign identity community. Identifiers such as names and numbers have always been the basis for any identity and communications systems, and while historically identifiers have been issued and maintained by central authorities, blockchains and other technologies today provide the ability for individuals, organizations, and things to register identifiers in a self-sovereign way, i.e. without any intermediaries. DIDs standardize this concept in a way that works with multiple decentralized systems such as Sovrin, Bitcoin, Blockstack, uPort, Veres One.
The Decentralized Identity Foundation (DIF) has started a community effort to implement a "Universal Resolver" and other tools for working with DIDs. These components fulfill a similar purpose as Bind does in the DNS system: Given a DID, one can resolve it to discover public keys, service endpoints, and other metadata associated with the entity identified by the DID. This enables higher-level data structures and protocols such as Verifiable Credentials.
