A survey on decentralized identity management systems

Digital identity is a crucial tool in the field such as healthcare, education and government. It serves as the foundation for establishing presence in cyberspace. With the increasing demands for security, control and portability, digital identity has evolved through four stages: centralized, federated, user-centric and self-sovereign identity. Among these, the decentralized identity represents the self-sovereign identity stage, emphasizing the idea of the user fully control over the user’s identity. Blockchain, as the key technology enabling decentralization, provides robust support for the decentralized identity through its transparent, distributed and immutable characteristics. We investigate the blockchain-based Decentralized Identity Management Systems (DIDMS), analyzing their advantages over the previous systems in terms of the enhanced control, privacy, and security. We propose a four-phase architecture for the DIDMS, detailing how the users can achieve self-management through the DIDMS without relying on the centralized entities. Furthermore, this investigation compares the various solutions with the core practical properties, explores the relationships between these features, and summarizes the evaluation criteria for the DIDMS. Additionally, the work evaluates both classical and cutting-edge DIDMS solutions and discusses the challenges faced by the DIDMS, along with potential solutions, providing direction for future research and practice.