The digital boom brought empowerment to seamless connectivity by enabling manufacturers to harness the power of the Internet into their products, opening up the world of the Internet of Things (IoT). However, such connectivity has also brought the side effect of such power being abused by unscrupulous agents, who scan open ports for services and exploit vulnerabilities in the system. The Mirai botnet malware attack is one such example that caused havoc by compromising millions of IoT devices having unpatched/weaker security. There is an increasing need to enable IoT devices to be fully patched and secured, but such methods are often under attack. This paper examines a stealth technology and its impact on the CPU and power consumption to secure resource-constraint IoT devices that are growing exponentially. By enabling secure remote operations and management of such devices using a unique but practical method of security called "Port Knocking," we can ensure timely patching of security vulnerabilities in a safe and stealthy manner. Our experimental results on a resource-constraint IoT device show that port knocking not only secures the device and provides a secure remote management option but also helps in keeping its power consumption low. The results obtained make it an effective security layer for securing resource-constraint IoT devices.