Abstract: In this paper we propose a security LEACH (S-LAECH) protocol based on attack detection. According to the characteristics of LEACH routing protocol, this method keeps test parameters at the end of package in the periods of head node selection and data transmission. Thus, judgment of HELLO flood attack and Sybil attack of sensor network is jointly made according to the node power and received signal strength. At the same time, aiming at attacks of cluster head nodes and cluster member nodes, two detecting methods are used to improve accuracy. Jakes channel model in a WSN real network space is established with NS-2 software. Using this model, security of S-LAECH is verified.

Key words: wireless sensor network, security routing protocol, intrusion detection, LEACH