ESP32 Microcontroller based Lightweight TLS 1.3 Client for IoT Applications

This article presents the implementation of a lightweight TLS 1.3 client that uses a minimal subset of cryptographic algorithms and libraries to achieve efficient and secure communication. Core algorithms were selected to ensure compatibility with most web servers, and a cryptographically secure pseudorandom number generator was integrated to enhance security. The client employs lightweight C/C++ libraries optimized for embedded systems and the Internet of Things, reducing resource consumption while maintaining essential security features. Designed with portability in mind, nonessential functions were removed to minimize memory usage and computational overhead. Session resumption was implemented to enable efficient reconnections without requiring a full TLS handshake. The article also provides execution times for cryptographic functions on the ESP32-C6 platform, offering insight into the performance of the proposed solution.