Abstract: This paper presents a study on the implementation of an encrypted communication solution in Internet of Things (IoT) devices, implemented on low-capacity microcontrollers and the TLS (Transport Layer Security) secure communication protocol. Faced with the challenges of security in IoT, such as the lack of standards and the prioritization of connectivity over security, we propose a methodology for simplified adaptation to the use of the TLS protocol for microcontrollers. Using the ESP32 microcontroller as the evaluation device, a microcontrolled system was implemented, and a series of practical tests were performed, both in client and server modes, evaluating security parameters, latency, and increases in TLS data packet sizes. The results demonstrate that, despite the increase in latency and data packet sizes, the ESP-32 was able to successfully establish a secure connection via TLS, ensuring the confidentiality, integrity, and authenticity of exchanged information and efficiently supporting the developed application. However, as one might expect, communication is still vulnerable to denial of service (DoS) attacks in both client and server modes, since this vulnerability can only be circumvented through DoS attack mitigation strategies. We believe that this research contributes to standardizing security in IoT, utilizing the implementation of the TLS protocol for the application of robust encryption and authentication methods.
