The Internet of Things (IoT) is advancing to prevail the application of the Internet, with the vision to connect everything around us. The deployment of IoT is advancing at a very fast pace, and relying on modified versions of the TCP/IP protocol suits. This rapid growth of the field is leaving a number of critical issues unresolved. Among the most critical issues are the quality of service and security of the delivered data. This research is set to tackle these issues through proposing a data delivery scheme that improves the quality of service (QoS) of classified data. The proposed solution relies on differentiating the priority of the delivered data, and to give preferences to secured and user-defined high priority traffic. The proposed solution denoted as Secured Traffic Priority Differentiation (STPD), is made to support any application, and is implemented at the Medium Access Control (MAC) sub layer. The proposed solution was tested in a virtual environment that simulates real scenarios using the Contiki operating system, using the Cooja simulator. The simulation results demonstrated a significant improvement of the proposed solution over the Carrier Sense Multiple Access Collision Avoidance, (CSMA/CA), by at 20%. The proposed solution worked to improve the channel utilization, data reliability, decreased latency of high priority traffic, and low priority traffic as well.