In the digital revolution, even secure communication between individuals, services and devices through centralized digital entities presents considerable risks. Service providers collect and store information that is used for data mining, profiling and exploitation without users' knowledge or consent. Having service providers continue to offer their centric solutions is inefficient in terms of duplication, has serious security lacunae and is cumbersome to the users. The Self-sovereign Identity (SSI) concept, which includes the individual's consolidated digital identity and verified attributes, enables the users of data to exert their ownership and gain insights from their data's usage. The authentication and verification of digital identity is essential to achieve the privacy and security of distributed digital identities. However, the current literature still lacks the comprehensive study on components of identity management as well as user privacy and data protection mechanisms in identity management architecture. In this paper, we provide a coherent view of the central concepts of SSI, including the components of identity proofing and authentication solutions for different SSI solutions. Firstly, we discussed an overview of Identity management approaches, introducing an architecture overview as well as the relevant actors in such a system and blockchain technology as solution for distributed user-centric identity. Then we analyzed the authentication and verification mechanisms in the context of digital identity. Finally, we discuss the existing solutions and point out the research gaps and elaborate challenges and trade-offs towards building a complete identity management system (IdMs).