Nowadays Wireless Sensor Networks (WSNs) are a very promising device to monitor environmental events, which are used in many application areas such as agriculture, environmental monitoring, air-water pollution, greenhouse, health monitoring, structural monitoring etc. Also, WSN needs effective and efficient way of collecting data from the area over which it is deployed, since the network consists of battery-operated nodes with limited energy. Improving the lifetime of WSN for continuous monitoring applications are very essential because of simple deployment, low installation cost, lack of cabling, and high mobility. The better energy conservation and reliable data transmission would be achieved in WSN by adopting efficient routing protocols for better and reliable communication. Also, security in data transmission in WSN is still a challenging task. Hence, a better way of encryption has to be computed to promote a reliable transmission between the nodes. In this paper discusses about different routing protocols which support energy efficiency and security techniques in WSN.