Existing approaches for protecting sensitive information stored (outsourced) at external "honest-but-curious" servers are typically based on an overlying layer of encryption that is applied on the whole information, or use a combination of fragmentation and encryption. The computational load imposed by encryption makes such approaches not suitable for scenarios with lightweight clients. In this paper, we address this issue and propose a novel model for enforcing privacy requirements on the outsourced information which departs from encryption. The basic idea of our approach is to store a small portion of the data (just enough to break sensitive associations) on the client, which is trusted being under the data owner control, while storing the remaining information in clear form at the external (honest-butcurious) server. We model the problem and provide a solution for it aiming at minimizing the data stored at the client. We also illustrate the execution of queries on the fragmented information.

The large adoption of the cloud paradigm is introducing more and more scenarios where users can access data and services with an unprecedented convenience, just relying on the storage and computational power offered by external providers. Also, users can enjoy a diversity and variety of offers, with the possibility of choosing services by different providers as they best suit their needs. With the growth of the market, economic factors have become one of the crucial aspects in the choice of services. However, security remains a major concern and users will be free to actually benefit from the diversity and variety of such offers only if they can also have proper security guarantees on the services. In this paper, we build upon a recent proposal for assessing integrity of computations performed by potentially untrusted providers introducing some optimizations, thus limiting the overhead to be paid for integrity guarantees, and making it suitable to more scenarios.

Abstract. Companies as well as individual users are adopting cloud solutions at an over-increasing rate for storing data and making them accessible to others. While migrating data to the cloud brings undeniable benefits in terms of data availability, scalability, and reliability, data protection is still one of the biggest concerns faced by data owners. Guaranteeing data protection means ensuring confidentiality and integrity of data and computations over them, and ensuring data availability to legitimate users. In this chapter, we survey some approaches for protecting data in the cloud that apply basic cryptographic techniques, possibly complementing them with additional controls, to the aim of producing efficient and effective solutions that can be used in practice.

Abstract. One truth holds for the healthcare industry -nothing should interfere with the delivery of care. Given this fact, the access control mechanisms used in healthcare to regulate and restrict the disclosure of data are often bypassed. This "break the glass" phenomenon is an established pattern in healthcare organizations and, though quite useful and mandatory in emergency situations, it represents a serious system weakness.In this paper, we propose an access control solution aimed at a better management of exceptions that occur in healthcare. Our solution is based on the definition of different policy spaces regulating access to patient data and used to balance the rigorous nature of traditional access control systems with the prioritization of care delivery.

No abstract