HL-CAIoT: Hybrid Lightweight Cipher for IoT with Chaotic Maps and Cellular Automata

The growing use of IoT devices has increased the demand for secure and efficient encryption. Most traditional algorithms are too complex to be applied in IoT systems due to the limited resources available. Based on this, the paper proposes a novel, lightweight hybrid cipher suitable for IoT applications. Chaotic maps and Cellular Automata (CA) are utilised to enhance the security level of the proposed cypher while maintaining minimal processing demands. The new cipher integrates Tinkerbell and Tent maps into a complex encryption sequence. Additionally, the S-box is generated using a Piecewise Linear Chaotic Map (PWLCM), further strengthening the encryption. This approach achieves strong security, as evidenced by a high NPCR of 99.6053, indicating high sensitivity to small input changes. It also records a high MSE value of 7157.7306, suggesting strong diffusion and scrambling. Furthermore, the key sensitivity achieved was 99.616% having less than 45 MB of memory usage in a Raspberry Pi 4 board with encryption time of 1.22 seconds. These results confirm that the cipher effectively protects IoT data. This lightweight cipher, which offers strong security without excessive power consumption, is ideal for IoT environments. Future work will focus on improving the performance of smaller devices and testing resilience against a broader range of attacks.