  Secure and reliable management of identities has become one of the greatest
challenges facing cloud computing today, mainly due to the huge number of new
cloud-based applications generated by this model, which means more user
accounts, passwords, and personal information to provision, monitor, and
secure. Currently, identity federation is the most useful solution to overcome
the aforementioned issues and simplify the user experience by allowing
efficient authentication mechanisms and use of identity information from data
distributed across multiple domains. However, this approach creates
considerable complexity in managing trust relationships for both the cloud
service providers and their clients. Poor management of trust in federated
identity management systems brings with it many security, privacy and
interoperability issues, which contributes to the reluctance of organizations
to move their critical identity data to the cloud. In this paper, we aim to
address these issues by introducing a novel trust and identity management model
based on the Blockchain for cloud identity management with security and privacy
improvements.
