The rapid evolution of Internet of Things (IoT) devices brings with it a wealth of technological advancements and opportunities for connectivity and automation. However, these advantages also bring significant security challenges. One of the major issues with IoT security is the large number of connected devices with varying security levels. Many IoT devices have limited resources, which makes implementing strong security measures challenging. This article presents a safe authentication mechanism for smart objects that allows smart devices and servers to authenticate each other. The protocol presented in this study is an improvement for another previous work, which was found to have vulnerabilities. To ensure the security of the new protocol, we conducted security analysis using AVISPA. The results of our analysis demonstrate the effectiveness and robustness of the proposed protocol in mitigating potential security threats and providing secure communication between the server and smart objects. This research contributes to the development of enhanced authentication mechanisms for the growing ecosystem of connected devices and highlights the importance of rigorous security evaluations in designing secure protocols for IoT domain.