Two Security Layers for Hierarchical Data Aggregation in Sensor Networks

Due to resource restricted sensor nodes, it is important to minimize the amount of data transmission among sensor networks so that the average network lifetime and the overall bandwidth utilization are improved. To reduce the amount of sending data, an aggregation approach can be applied along the path from sensors to the sink. It means computing and transmitting partially aggregated data to the end user rather than transmitting raw data in networks while optimizing the energy consumption. However, as sensor networks are often deployed in public or otherwise untrusted and even hostile environments, sensor nodes are prone to node compromise attacks and security issues such as data confidentiality and authentication. Hence, an end-to-end secure aggregation approach is required to ensure a healthy data reception. In this paper, we propose two layers for secure data aggregation in sensor networks. Firstly, we provide an end-to-end encryption scheme that supports operations over cypher-text. It is based on elliptic curve cryptography that exploits a smaller key size, allows the use of higher number of operations on cypher-texts, and prevents the distinction between two identical texts from their cryptograms. We proved that our method outperforms existing ones by providing higher security levels with less energy consumption. Secondly, we propose a new watermarking-based authentication that enables sensor nodes to ensure the identity of other nodes they are communicating with. Our experiments show that our hybrid approach of secure data aggregation enhances the security, significantly reduces computation and communication overhead, and can be practically implemented in on-the-shelf sensor platforms.