The technology known as wireless sensor networks, or WSNs, is developing quickly and offers excellent reliability in a wide range of innovative applications related to both public and military safety. Security measures are getting more and more crucial as wireless sensor networks advance. Handling security issues is crucial since sensor networks operate in hostile environments and deal with responsive data. Maintaining the energy required for communication is a crucial design objective of the WSN. Failure to do so could result in packet delivery delays, rapid energy depletion, and a decline in node performance owing to serious threats across the network. Furthermore, sensor nodes need strong cryptography algorithms in order to offer a longer lifespan and security services. It is already happened. Consequently, this maximizes the network's longevity and lowers energy consumption. Therefore, a hybrid technique combining an adaptive lion fuzzy-based clustering approach and modified elliptic curve cryptography (ECC)-based key management is proposed to identify cluster heads and enable safe data transfer between the cluster head and sink nodes. The suggested method also uses a hashing technique to provide mutual authentication between the base station and the destination nodes, since ECC uses a smaller key and offers a higher level of security.