Abstract : Due to numerous technical flaws, security concerns are increasing day-to-day. Security in Wireless Sensor Networks is the most dangerously weak effect. One of Wireless Sensor Networks' security issues is disturbances or intrusions. A hacker with access to the network has the ability to stop the entire flow process. In this instance, it's important to comprehend the device's intruder's function. The best technique for assessing and recognising threats that harm the entire network is intrusion detection. In order to achieve effective communication and as a result, to recognise any type of attack that affects the entire network, the intrusion problem requires recognising and restoring protection among nodes. The current work suggests a defect node identification technique to recognise intruders in a wireless sensor network when a few of the permitted sensor nodes halted. After optimization, the technique can result in fewer sensor node replacements and more data transmission reuse. We propose a novel technique called as key assisted monitoring approach for detection of fault nodes. According to our simulation, the suggested work increases the number of dynamic nodes by up to several times, reduces the rate of information loss by about half and can slow down the rate of energy vitality consumption by network performance parameters.