MAVLink or Micro Air Vehicle Link which is an unmanned system lightweight message serialization protocol. This protocol is commonly used in autopilot systems, especially ArduPilot and PX4 and provides advanced features not only for monitoring and controlling the mission of unmanned systems but also for integration into the Internet. Since the MAVLink protocol is carried over wireless channels, it's vulnerable against various attacks. In our groups, numbers of methods have been employed to secure data transmission. The implementation of various algorithms is employed. Performance evaluation is carried out in terms of QoS. Security evaluation is also performed for both passive and active attacks.