“…Sensor clocks are synchronised using the energy-efficient time synchronization protocol (ETSP) [23]. Recent work [20,24,25,26,27] also highlighted countermeasures against attacks in en-route filtering with an emphasis on network lifetime. Several work focused on network lifetime extension [10,28,29,30,31], energy efficiency and network lifetime [32,33,34], and energy efficiency [35,36,37,38,39] and privacy [40,41,42] using various techniques.…”