Secure LoRa-Based Transmission System: An IoT Solution for Smart Homes and Industries

This article addresses the lack of low-cost, secure image-transmission solutions for IoT systems in remote environments. The design and implementation of a complete LoRa-based transmission system using ESP32 microcontrollers and Ebyte E220 modules, featuring AES-CBC encryption, HMAC integrity protection, and a custom retransmission protocol, are presented. The system achieves 100% packet delivery ratio (PDR) for 20 kB images over distances exceeding 2 km under line-of-sight conditions, with functional transmission up to 4.1 km. Image transmission time ranges from 35 s (0.1 m) to 110 s (600 m), while energy consumption increases from 4.95 mWh to 15.18 mWh. Critically, encryption imposes less than 1% overhead on total energy consumption. Unlike prior work focusing on isolated components, this article provides a complete, deployable architecture combining (i) low-cost hardware (<USD 50 total), (ii) long-range LoRa communication, (iii) custom reliability mechanisms for fragmenting 20 kB images into 100 packets, and (iv) end-to-end cryptographic protection, all evaluated experimentally across multi-kilometer distances. These findings demonstrate that secure long-range image transmission using commodity hardware is feasible and scalable for smart home and industrial monitoring applications.