Design of Multiplicative Inverse Value Generator using Logarithm Method for AES Algorithm

Advanced Encryption Standard (AES) algorithm is one of the most widely used symmetric block cipher that is utilized in data protection through symmetric cryptography algorithm, as it offers high efficiency and ability in securing information. In AES, the SubByte/InvSubByte transformation costs an amount of memories for the lookup tables (LUT) that leads to area usage in hardware. As per mathematical equations, the SubByte/InvSubByte is able to share the same resource which is the multiplicative inverse value table. Instead of using LUTs, the multiplicative inverse values can be generated on-the-fly as needed. Therefore, this paper presents the custom hardware design and implementation of multiplicative inverse value generator using logarithm method specifically for AES algorithm. The logarithm method benefits the usage of antilog and log values in obtaining the multiplicative inverse value. The EDA tools as Intel Quartus Prime, Synopsys Design Compiler and IC Compiler are used to perform functional simulation, on synthesis analysis and block-level implementation. Detailed comparison is made between this work and previous implementation. The newly designed multiplicative inverse value generator has achieved the improvement on speed and area as compared to previous implementation. The area of the design is reduced around 8.5% with current improvement of 63.091 μm², while the speed has increased to 2.54 ns with a positive slack of 0.11 ns, which is shorter than the previous implementation. The new design also outreached the performance of the common LUT-based design.