A Very Compact Hardware Implementation of the MISTY1 Block Cipher


This paper proposes compact hardware (H/W) implementation for the MISTY1 block cipher, which is an ISO/IEC18033 standard encryption algorithm. In designing the compact H/W, we focused on optimizing the implementation of FO/FI functions, which are the main components of MISTY1. For this optimization, we propose two new methods; reducing temporary registers for the FO function, and shortening the critical path for the FI function. According to our logic synthesis on a 0.18-μm CMOS standard cell library based on our proposed method, the gate size is 3.95 Kgates, which is the smallest as far as we know.