NISp1-08: Secure Aggregation in Large Scale Overlay Networks

Overlay networks have been very useful in solving large scale data dissemination problems. In this paper, we consider the case of data gathering which is the inverse of dissemination problem. In particular, we focus on a scenario where an organization or a constellation of organizations is interested in gathering data from large number of nodes spread across the administrative boundaries. Providing individual nodes with full assurance that the privacy of their data won´t be compromised is a critical problem in achieving the true benefits of this collaborative process. We provide a novel solution to the problem by employing a threshold homomorphic cryptosystem which allows processing of encrypted data without revealing anything about the underlying private data. The threshold property of the cryptosystem ensures that no single node is able to decrypt the aggregate results. The proposed solution provides excellent scale-up properties while preserving privacy and secrecy of the data even among malicious adversaries.