The document discusses the state of blockchain-based decentralized identifier (DID) technology as reflected in patent applications up to June 15, 2020. It highlights key innovation entities like Alibaba, IBM, and Microsoft, and outlines various application areas such as authentication/verification, management, and exchange of DIDs. The document also examines a novel protocol for anonymizing the exchange of identifiers in financial services using blockchain, ensuring privacy and unlinkability among involved parties.