Accounting for privacy in the cloud computing landscape

While offering many benefits, cloud computing also introduces serious privacy challenges as evidenced by recent security breaches and privacy incidents. In this dissertation, we argue that overcoming these privacy challenges requires cooperation between the various actors in the cloud computing landscape, i. e., users, service providers, and infrastructure providers. All these different actors have clear incentives to care for privacy and, with the contributions presented in this dissertation, we provide technical approaches that enable each of them to account for privacy. As our first contribution to support users in exercising their privacy, we raise awareness for their exposure to cloud services in the context of email services as well as smartphone apps and enable them to anonymously compare their cloud usage to their peers. With privacy requirements-aware cloud infrastructure as our second contribution, we realize user-specified per-data item privacy policies and enable infrastructure providers to adhere to them. We furthermore support service providers in building privacy-preserving cloud services for the Internet of Things in the context of our third contribution by enabling the transparent processing of protected data and by introducing a distributed architecture to secure the control over devices and networks. Finally, with our fourth contribution, we propose a decentralized cloud infrastructure that enables users who strongly distrust cloud providers to completely shift certain services away from the cloud by cooperating with other users.