A Comprehensive Review of Security Protocols and Methods Across IoT Architecture Layers

This paper presents an extensive structure for IoT security, introducing a four-layered reference model that addresses the unique vulnerabilities at each layer of IoT architecture. The model comprises a customized set of privacy and security rules created especially for safeguarding IoT assets in a variety of applications. Also, a four-phase methodology is implemented focused on improving IoT security based on Security Level Certificates that provide and evaluate the necessary security measures for various IoT devices and networks. These phases cover significant stages from the initial device identification till decommissioning, offering a framework for both proactive and adaptive security measures. Key technologies which support these Endorsements are also examined, that involves blockchain, artificial intelligence, and lightweight cryptographic protocols. This study suggests by reviewing assessment criteria and future challenges, likewise changing risks like quantum data processing and legal constraints. A flexible and scalable security foundation is offered by this precise and layered approach, which is essential for protecting the growing IoT ecosystem.