Secure data aggregation with multiple encryption

Data aggregation has been put forward as an essential technique to achieve
power efficiency in sensor networks. Data aggregation consists of processing data
collected by source nodes at each intermediate node enroute to the sink in order to
reduce redundancy and minimize bandwidth usage.
The deployment of sensor networks in hostile environments call for security
measures such as data encryption and authentication to prevent data tampering by
intruders or disclosure by compromised nodes. Aggregation of encrypted and/or
integrity-protected data by intermediate nodes that are not necessarily trusted due
to potential node compromise is a challenging problem. We propose a secure data
aggregation scheme that ensures that sensors participating to the aggregation mechanism
do not have access to the content of the data while adding their sensed values
thanks to the use of an efficient homomorphic encryption scheme. We provide a
layered secure aggregation mechanism and the related key attribution algorithm
that limits the impact of security threats such as node compromises. We also evaluate
the robustness of the scheme against node failures and show that such failures
are efficiently recovered by a small subset of nodes that are at most m hops away
from the failure.