This thesis addresses the design of a secure-by-design framework for energy communities, with a particular emphasis on communication and the components needed to ensure its security. The highly interconnected nature of this ecosystem, combined with the criticality of the infrastructure involved, necessitated the development of a communication model capable of meeting performance and environmental constraints, while also addressing fundamental security and safety requirements. Renewable Energy Communities are innovative and participatory models for local production, sharing and consumption of renewable energy. Their objective consists in delivering environmental, economic and social value together with the generation of clean energy. The work starts from the IEC 62443-Based Framework for the RECs to analyze the message brokers and the MQTT protocol, highlighting their main characteristics, strengths and vulnerabilities, defining the technological context within which the research is situated.