With the growing needs of technology and connectivity with the internet, a huge role is laid on WSN for many different applications. Say health care, traffic surveillance, smart house or most importantly in the defence area, sensor networks play a crucial role. This is why sensor networks pose unique security challenges because of their inherent limitations in communication and computing. Dense deployment of sensor networks in an unattended environment makes sensor nodes vulnerable to potential attacks. With these demands, the confidentiality, integrity and authentication of the communicated information becomes very important. In this paper, we have focused on a lightweight encryption method which encompasses faster encryption thereby, bringing down the computing time which increases the overall lifetime of the sensor network. The introduction of both symmetric and asymmetric cryptography in the two phase hybrid encryption algorithm, check marks the main aim of cryptography, i.e, Confidentiality, Integrity and Authenticity. Moreover hybrid encryption attempts to exploit the advantages of both symmetric and asymmetric encryption. © 2016 IEEE.