Efficient FPGA implementation of LUT-based Mix-Column Serial Transform for lightweight cryptography

Resource-constrained platforms (e.g., IoT nodes and embedded sensors) require diffusion layers that deliver strong security under strict area, latency, and power budgets. This paper presents an FPGA-optimized implementation of the Mix-Column Serial Transform (MCST) that replaces finite-field multipliers and large XOR networks with a compact log/antilog look-up table (LUT) datapath and a lightweight comparator-based reduction. The proposed architecture stores 256 × 8-bit logarithm and antilogarithm tables in ROM, converts Galois Field (256) (GF(256)) multiplication into an integer addition followed by conditional reduction modulo 255, and orchestrates computation with a small FSM. Implemented in VHDL and validated on a Xilinx Spartan-3 (XC3S500E-5FG676), the design achieves a throughput of 804.42 Mbps at 301.66 MHz with only 41 slices and 0.057 W power. Beyond cryptography, the LUT-based GF(256) core can accelerate reversible linear transforms in domains like image/audio security and compression. We discuss limitations (8-bit focus) and outline future work, including ML-guided LUT partitioning for further FPGA efficiency.