Substitution Permutation Network based Lightweight Ciphers with Improved Substitution Layers for Secure IoT Applications

This work aims to improve the design strategies of encryption algorithms desirable for secure IoT communication. Reduced hardware architectures for S-box modules of the lightweight ciphers specifically KLEIN, Midori and PRINCE are proposed. The proposed S-boxes are designed based on reuse of minterms technique to obtain minimum hardware in terms of logic gates. It is observed that the modified S-box contained in the substitution layer results in a decrease in the resource utilization of the overall cipher. The architectures also achieve better performance in terms of throughput and energy as compared to the other implementations of state-of-the-art ciphers. Simulation results for each cipher are determined from the PAR (Place and Route) report, and are compared fairly on the same FPGA platforms to bring uniformity in comparison.