Abstract: Clustering is an effective and practical way to enhance the system performance of Wireless Sensor Networks (WSNs). In WSNs, it is highly a difficult task to achieve secure data transmission. In existing system, some of the protocols such as SecLEACH, GS-LEACH, and RLEACH were used, but orphan node problem exists. Thus by using these protocols, the orphan node problem is solved due to Node-to-node communication. Secure data transmission for Cluster –based WSNs (CWSNs) can be provided with help of protocols. In existing system, two secure and efficient Data transmission protocols namely SET-IBS and SET-IBOOS scheme were proposed SET-IBS has a protocol initialization prior to the deployment and operates in round communication. SET-IBOOS operates similarly to the previous SET-IBS. The feasibility of the SET-IBS and SET-IBOOS protocols with respect to the security requirement and security analysis various attacks. In this paper, a modified protocol SET-IBS has proposed that formed dynamically, randomly and periodically. Thus the probability of two nodes will share a key to orphan rate of the orphan node problem. SET-IBOOS system lifetime will be increased. The time of FND in both SET-IBS is shorter than that of LEACH protocol due to the security overhead on computation cost of the IBS process.