Wireless Sensor Networks (WNS) mostly rely on multi-hop transmission to deliver a data packet from one node to another node through a set of intermediate nodes. The amount of communication and energy consumption can be reduced by data aggregation operation. Some of the optimal nodes in the network are used for data gathering and to perform data aggregation. On the other hand, these nodes may not aware whether they are aggregating true data or false data given by any malicious nodes in the network which leads to large data-error. This problem is taken into account and this paper presents a heavy weight security (HWS) algorithm for providing a secure data aggregation model for WSN nodes. HWS algorithm is carried out in three different consequent stages such as: (1). A preliminary node authentication and data verification process; (2). A node-ID, and node-location based public key is generated encrypting and decrypting the data packets transmitted and received; finally, (3). Aggregated data delivery on-time, on-demand from BS. The entire process of the HWS is simulated using NS-2 simulator and the results are compared with the existing approaches in order to evaluate the performance.