Internet of Things (IoT) security is critical, particularly for sensitive applications like smart homes and healthcare. A distributed key management approach increases security and privacy by effectively assigning cryptographic processes to a local entity. When user mobility, certification generation time, and communication overhead are taken into account, simulation results validate the effectiveness of the method. The plan prioritizes effective and safe data handling while meeting a variety of demands within a heterogeneous Internet of Things network. This paper, addresses the ongoing issues with cryptographic protocol standards for various Internet of Things applications. Since IoT is so complex, there are security concerns. This study looks at the solutions cryptographic protocols that enable safe communications across a range of IoT applications. In addition, it discusses the continued difficulties in developing cryptographic protocol standards for various Internet of Things applications. This article highlights security vulnerabilities in existing IoT systems, analyzes existing cryptographic standards, and highlights the need for lightweight cryptography solutions.