SEP 2 P : Secure and Efficient P 2 P Personal Data Processing

Personal Data Management Systems are flourishing allowing an individual to integrate all her personal data in a single place and use it for her benefit and for the benefit of the community. This leads to a significant paradigm shift since personal data become massively distributed. In this context, an important issue needed to be addressed is: how can users/applications execute queries and computations over this massively distributed data in a secure and efficient way, relying exclusively on peer-to-peer (P2P) interactions? In this paper, we motivate and study the feasibility of such a pure P2P personal data management system and provide efficient and scalable mechanisms to reduce the data leakage to its minimum with covert adversaries. In particular, we show that data processing tasks can be assigned to nodes in a verifiable random way, which cannot be influenced by malicious colluding nodes. Then, we propose a generic solution which largely minimizes the verification cost. Our experimental evaluation shows that the proposed protocols lead to minimal private information leakage, while the cost of the security mechanisms remains very low even with a large number of colluding corrupted nodes. Finally, we illustrate our generic protocol proposal on three dataoriented use-cases, namely, participatory sensing, targeted data diffusion and more general distributed aggregative queries.