ATTIA, Meriem2024-10-072024-10-072024-06-09http//localhost:8080/jspui/handle/123456789/12044With the rapid rise of Internet of Things (IoT) devices, new opportunities are emerging, but this also brings significant data security and privacy challenges. Securing data from these devices has become a priority, requiring innovative and robust solutions. To guarantee the protection and confidentiality of the information exchanged, one approach proposes the use of Blockchain technology and smart contracts to set up a secure communication system in the IoT. The purpose of this study is the establish a secure communication system for IoT environments using Blockchain technology and smart contracts. The main objective is to ensure the confidentiality, integrity, and authenticity of data exchanged between IoT devices while respecting the limited resource constraints of these devices. To do this, several smart contracts have been developed to manage data access, storage, and verification. Experimental results demonstrate that the use of Blockchain and smart contracts significantly improves data security by providing trust and transparency mechanisms, thereby overcoming current security challenges in IoT environments.enInternet of Things (IoT), communication system, security, Blockchain, smart contract.Thesis