Wireless Sensor Network (WSN) is a set of electronic sensor nodes that are used to measure various environmental parameters such as air temperature, humidity, light, physical movement, and others. WSN takes measurements from multiple points that are spread widely and continuously over a period of time. The WSN protocol is designed to have very low power consumption. The most popular example of the WSN protocol is Zigbee, which is based on the IEEE 802.15.4 standard. WSN uses a multi-hop communication system in which each node can act as a router and can be directly involved in the routing process. This characteristic makes WSN very vulnerable to security threats especially threats on the network layer. Sinkhole attack is an active routing attack on a very dangerous network layer because it modifies packet contents, modifies, re-send and fake the contents of packet . There are several methods of detection and mitigation for sinkhole attacks, there are Delphi method and Multipath routing protocol AODV. But there has been no detailed discussion of the security strategy for both methods. This study discusses the security strategy to achieve a balance between security and usability in WSN applications for both methods.