Distributed sensors are the eyes and ears of a smart grid which provide information vital for monitoring and controlling the entire power generation, transmission, and distribution systems. Secure exchange of information among the sensing and decision-making entities is essential as failures may bring the entire system on its knees. With the rapid growth in the number of distributed sensors, drones have a myriad of applications. A swarm of drones could also be deployed in war zones and disaster-stricken areas where a secured intercommunication is of paramount importance for survivability and for successful mission completion. In this paper, a secure mechanism is proposed based on mobile agents to secure information exchange with minimum overhead. An Agent Administrator (AA) automatically clones and sends a secure mobile agent (SMA) to the target sensors or drones to scan and check their security status. Then, the dispatched SMAs send feedbacks to the server AA or other members. In case of sensors, the closest terminal unit to which the sensors are directly connected is designated as an AA, which is capable of checking authentication and scanning for vulnerabilities. In the case of drones, any one of them or multiple of them could be designated as the AA and the flagged feedback is broadcast to all other nodes or drones thereby providing them security status updates. A modified Nagle’s Algorithm is also proposed to support real-time video transmission. The experimental results validate the effectiveness and convenience of the proposed system.