Area-Efficient Hardware Architectures of MISTY1 Block Cipher

In this paper, state-of-the-art hardware implementations of MISTY1 block cipher are presented for area-constrained wireless applications. The proposed MISTY1 architectures are characterized of highly optimized transformation functions i.e. FL and {FO-XOR-EKG}. The FL function re-utilizes logic AND-OR-XOR combinations whereas {FO-XOR-EKG} function explores 2 x compact design schemes for s-boxes implementation. A Combined Substitution Unit (CSU) and threshold area implementation are proposed for s-boxes based on Boolean reductions and Common Sub-expression Eliminations (CSEs). Besides, {FO-XOR-EKG} function is designed for manifold operations of FO / FI functions, 32-bit XOR operation and extended key generation thereby reducing the area. Hardware implementations on ASIC 180nm, 1.8V standard library cell realized compact and threshold MISTY1 designs constituting 1853 and 1546 NAND gates with throughput values of 41.6 Mbps and 4.72 Mbps respectively. A comprehensive comparison with existing cryptographic hardware designs establishes that the proposed MISTY1 architectures are the most area-efficient implementations till date.