Hierarchical Concealed Data Aggregation for Wireless Sensor Networks

In wireless sensor networks, performing data aggregation while preserving data confidentiality is a challenging task. Recently, privacy homomorphism based secure data aggregation schemes have been proposed to achieve seamless integration of data confidentiality and aggregation. If sensor data are encrypted with different keys, however, these schemes do not allow hierarchical data aggregation, thereby limiting the benefit of data aggregation. This paper presents a novel hierarchial concealed data aggregation protocol that allows the aggregation of data packets which are encrypted with different keys. Hence, regardless of the encryption key, data collected from all sensor nodes can be aggregated without violating data confidentiality. Moreover, during the decryption of aggregated data, the base station is able to classify sensor data based on the encryption key.