Private Over-threshold Aggregation Protocols over Distributed Databases

Abstract. In this paper, we revisit the private over-threshold data aggregation problem, and formally define the problem’s security requirements as both data and user privacy goals. To achieve both goals, and to strike a balance between efficiency and functionality, we devise a novel cryptographic construction that comes in two schemes; a fully decentralized construction and its practical but semi-decentralized variant. Both schemes are provably secure in the semi-honest model. We analyze the computational and communication complexities of our construction, and show that it is much more efficient than the existing protocols in the literature. Finally, we show that our basic protocol is efficiently transformed into a stronger protocol secure in the presence of malicious adversaries, together with performance and security analysis