The Internet of Things (IoT) is increasingly affecting human lives in multiple profound ways. “Things” have the ability to communicate, generate, transmit and store data over the network connection. During each communication between “Things”, the data transmitted is potentially vulnerable to malicious attacks, loss, distortions and interruption which impair functionality, system efficiency and user satisfaction. Therefore, communications between things need to be authenticated, authorized, secured and ensured to have high privacy by applying a strong authentication protocol. The aim of this research is to enhance the authentication protocol, starting by reducing the heavy use of storage in “Things”, and eliminating unnecessary messages during authentication steps. This research represents a security performance analysis and enhancement authentication for the IoT. The results indicate that the enhanced protocol has a positive effect on minimizing packet length and time performance compared with the other two protocols used for comparative purposes, with 33% increased the proposed protocol performance.