Design and Implementation of SM4 Block Cipher Based on Composite Field

Abstract

In this paper, a new method based on composite field is proposed. Through isomorphism bit matrices, the calculation by changing finite field inversion from GF(28) to GF(((22)2)2) is simplified to reduce the computational difficulty and a more compact S-box is realized. The area decreases by 27% than Look-up Table. On the basis of that, the SM4 algorithm is implemented. The area of this IP core is only 7 612 gates synthesized under the smic0.13 μmCMOS process. Therefore this improved design is very helpful for area-limited condition such as IC cards.