Performance Analysis of AES Modes of Operation on an ESP32-based Platform : A Comparison of Execution time and RAM Usage in IoT Context

The rapid expansion of the Internet of Things (IoT) has introduced a wide range ofconnected devices, many of which operate under strict hardware constraints. En-suring secure communication in these environments is a challenge, particularly forhobbyist and small-scale developers with limited resources. This thesis investigateshow different AES encryption modes—ECB, CBC, CFB, and CTR—perform on alower-end IoT development board, the Pycom FiPy, built on the ESP32 microcon-troller. The study measures execution time and RAM usage across varying payloadsizes to evaluate the trade-offs between security and performance. Results show thatCBC and CTR offer the best balance of security features and processing speed, whileCFB consistently performed the worst in terms of execution time. These findings of-fer practical insights into selecting suitable encryption methods for IoT.