Today, our identities and all of our digital interactions are dominated and controlled by entities, some of which we may not even be aware of.However, a promising solution to these issues has emerged in the form of decentralized identity or self-sovereign identity, a concept that empowers end-users with the control of their own credentials and digital identity. However, decentralized identity (DID) systems face several important challenges hindering their deployment. First, DID systems assume the spontaneous existence of a credential-issuance ecosystem, creating a bootstrapping problem.The first part of this thesis addresses this challenge by porting identities securely from existing web services using a decentralized oracle system. Next, DID systems, like cryptocurrency ones, require that private keys be safely managed, creating a risk of identity loss. Common approaches to key management use self-custodial authentication mechanisms with unclear security guarantees or offload key storage to a custodian sacrificing ownership. The second part of this thesis improves upon the state-of-the-art via: (a) an authentication framework to model existing mechanisms and the design of more secure mechanisms, and (b) decentralized secret storage protocols to decentralize ownership even in custodial approaches.