How could privacy play a key role in protecting digital identities? How could we merge privacy law, policies, regulations and technologies to protect our digital identities in the context of connected devices and distributed systems? In this book, the author addresses major issues of identity protection and proposes a service-oriented layered framework to achieve interoperability of privacy and secure distributed systems. The framework is intended to distill privacy-related digital identity requirements (business interoperability) into a set of services, which in turn can be implemented on the basis of open standards (technical interoperability). The adoption of the proposed framework in security projects and initiatives would decrease complexities and foster understanding and collaborations between business and technical stakeholders. This work is a step toward implementing the author's vision of delivering cyber security as a set of autonomous multi-platform hosted services that should be available upon user request and on a pay-per-use basis.