Patent ID: 7907548

Claim:
A method for electing aggregator nodes in a network, wherein the network ( 1 ) comprises a plurality of sensor nodes (S i ) to measure data, and wherein at least one of the sensor nodes (S i ) functions as aggregator node (A) to aggregate sensored data obtained by at least a subset of the sensor nodes (S i ), and wherein the network further comprises at least one sink node ( 2 ) to collect data aggregated by the aggregator nodes (A), the method comprising: establishing pairwise secret keys (k i ) between a current aggregator node (A t ) and each sensor node (S i ) of the subset of sensor nodes from which the current aggregator node (A t ) obtains sensored data; at each of the sensor nodes (S i ) of said subset, choosing a random number (r i ) and encrypting the random number (r i ) using the established key (k i ); providing a communication chain between the sensor nodes (S i ) of said subset and summing the encrypted random numbers (r i ) of all sensor nodes (S i ) of said subset; and determining a new aggregator node (A t+1 ) on the basis of the resulting sum according to a predefined calculation scheme.