Design of Cryptography Algorithm for Data Security of a IoT System

This research explores the data security of the Internet of Things (IoT), with a specific focus on designing cryptographic algorithms suitable for the resource-constrained ESP32 microcontroller. Referencing existing Advanced Encryption Standard (AES) and Data Encryption Standard (DES) algorithms, the proposed lightweight block cipher algorithm is specifically tailored for the ESP32 platform. It leverages encryption techniques such as key generation, XOR operations, custom-designed S-boxes, custom-designed P-boxes, and row permutation methods. Understanding the structure of ESP32, the algorithm is designed to align the process data with native word size which takes advantage of optimizing the register operation. Performance analysis was conducted to balance security and execution time. The results indicate that the combination of encryption techniques including key generation, XOR operation, S-box, P-box, and row permutation yields optimal randomness, with nearly 50% of bit changes in the SAC test. The design of the proposed cryptography algorithm is recommended to use four rounds of encryptions, as it passes the SAC test in the fourth round and exhibits the shortest execution time which is 3ms. Implementation on ESP32 confirms its feasibility for Internet of Things (IoT) applications.