n-LDA: n-Layers Data Aggregation in Sensor Networks

We present a protocol for secure data aggregation in wireless sensor networks that offers end-to-end data confidentiality by using homomorphic functions and interleaved encryption. Hop-by-hop aggregation in sensor networks is an efficient way to save energy. Node compromises in hostile environments require protocols for data aggregation where the intermediate nodes contribute with their own values to the aggregated data without getting access to it. Homomorphic encryption schemes allow aggregation on ciphertext and thus can provide end-to-end data confidentiality. We propose a layered data aggregation protocol which ensures that, in the presence of less than n captured nodes, an attacker cannot get access to any aggregated data from the network. When more than n nodes are captured, the attacker can only get access to the aggregated values received by the captured nodes. Our protocol is resilient to node failure and no pre-built tree for data aggregation is needed.