A computer-based system and method for secured privacy preservation scheme while data aggregation in a non-hierarchical wireless sensor network that lacks peer-to-peer communication between the communicating sensor nodes is disclosed. The method and system adopts formation of self-adaptive efficient cluster formation for robust privacy preservation in the network by grouping the multiple sensor nodes in the network to form multiple clusters that enables low computation overhead and high scalability in the network. The method and system of the invention discloses an effective twin-key management scheme that provides establishment of secure communication among the sensor nodes and the secure communication between at least one sensor node with the sever node performing the function data aggregation of the data collected by the sensor nodes.