Trust Models for Blockchain-Based Self-Sovereign Identity Management: A Survey and Research Directions

Existing identity management systems either use a centralized authentication server or rely on identity providers to authenticate users for gaining access to various services. These systems have failed to safeguard user data privacy and do not encourage the portability of identity data. Self-sovereign identity is a new approach in identity management where entities have control of their digital identity. The emerging blockchain technology enables self-sovereign identity management, a decentralized identity management model that eliminates identity providers as a trusted third party. Due to the decentralized nature of blockchain network, this new paradigm of identity management demands different trust requirements. This research provides the first thorough review in literature addressing trust management for blockchain-based self-sovereign identity. A formal and comprehensive trust model proposed for blockchain-based Self-Sovereign IDM will be explored. Besides reviewing trust requirements, the paper also surveys the state-of-the-art of blockchain technology for self-sovereignty in identity management. This survey provides a critical analysis for existing research which sheds light on various opportunities for enhancing security and privacy of blockchain-based self-sovereign identity management and the improvement of trust management. The paper concludes with presenting research gaps and suggestions for future work in the area.