Design Space Exploration for High-Speed Implementation of the MISTY1 Block Cipher

This paper proposes 2 × unrolled high-speed architectures of the MISTY1 block cipher for wireless applications including sensor networks and image encryption. Design space exploration is carried out for 8-round MISTY1 utilizing dual-edge trigger (DET) and single-edge trigger (SET) pipelines to analyze the tradeoff w.r.t. speed/area. The design is primarily based on the optimized implementation of lookup tables (LUTs) for MISTY1 and its core transformation functions. The LUTs are designed by logically formulating S9/S7 s-boxes and FI and {FO + 32-bit XOR} functions with the fine placement of pipelines. Highly efficient and high-speed MISTY1 architectures are thus obtained and implemented on the field-programmable gate array (FPGA), Virtex-7, XC7VX690T. The high-speed/very high-speed MISTY1 architectures acquire throughput values of 25.2/43 Gbps covering an area of 1331/1509 CLB slices, respectively. The proposed MISTY1 architecture outperforms all previous MISTY1 implementations indicating high speed with low area achieving high efficiency value. The proposed architecture had higher efficiency values than the existing AES and Camellia architectures. This signifies the optimizations made for proposed high-speed MISTY1 architectures.