NBLBC: A MARS-Like lightweight block cipher for NB-IoT

Abstract Securing terminal data transmission remains a critical challenge in Narrowband Internet of Things (NB-IoT) ecosystems, where conventional lightweight block ciphers struggle to reconcile security robustness with stringent resource constraints. Thus, A new lightweight block cipher named NBLBC is proposed to mitigate terminal data leakage vulnerabilities in NB-IoT. The proposed NBLBC features a double-layer, 8-branch MARS-like structure. A key contribution lies in the development of a double-layer hybrid linear layer, which significantly enhances the diffusion performance compared to traditional MARS-based designs. The nonlinear layer uses a top-down quantum gate search approach to design an S-box, achieving a quantum circuit depth of 55 (T-depth=7). For practical validation, an NB-IoT application framework is implemented using three Nexys A7 FPGA development boards. The NBLBC architecture delivers 1461.4 Gate Equivalents(GEs) hardware footprint (UMC 0.18 μ m process) with 6.84 μ J/bit energy consumption, achieving 20.5% area reduction and 50.36% energy consumption improvement over SKINNY.