HAIL: a family of high-diffusion lightweight block ciphers for internet of things security

Abstract The accelerated evolution of Internet of Things (IoT) technology has made it crucial to secure information from resource-constrained devices. Therefore, a high-diffusion lightweight block cipher family, called HAIL, is proposed in this work to provide higher security for IoT devices while minimizing area and power consumption. In more detail, HAIL constructs an improved Lai-Massey structure with the high diffusion of the SPN structure and the symmetry of the Feistel structure. Additionally, the differential probability of 1 in the Lai-Massey structure is successfully avoided by introducing additional nonlinear operations. Compared to traditional ciphers employing the Lai-Massey structure, HAIL significantly reduces area consumption by discarding the modular component and adding shift operations into the Lai-Massey branch, thereby enhancing security. Moreover, HAIL selects an involutive, low-area S-box using Genetic Programming (GP) and combines it with an S-box that exhibits strong side-channel resistance, making the nonlinear part of HAIL advantageous for side-channel protection. Detailed testing verifies that HAIL64 and HAIL128 achieve full diffusion and avalanche effect within one and three rounds, respectively, showcasing effective diffusion properties. The throughput-to-area ratios of HAIL64 and HAIL128 at 100 kHz are 0.202 and 0.234 (SMIC 0.18 μm) respectively. Experimental results indicate that HAIL is immune to both linear and differential cryptanalysis. Finally, HAIL demonstrates high security redundancy against impossible differential attacks and Meet-In-The-Middle (MITM) attacks, among others, while its low power and area requirements address critical IoT constraints.