Atri Rudra, Pradeep K. Dubey, Charanjit S. Jutla, Vijay Kumar, Josyula R. Raoand Pankaj Rohatgi

Efficient Implementation of Rijndael Encryption with Composite Field Arithmetic

Abstract : We explore the use of subfield arithmetic for efficient implementations of finite field arithmetic especially in the context of the AES block cipher. Our technique involves mapping field elements to a composite field representation. We describe how to select a representation which minimizes the computation cost of the relevant arithmetic, taking into account the cost of the mapping as well. Our method results in a very compact and fast gate circuit for AES encryption.

In conjunction with bit-slicing techniques applied to parallelizable modes of operation (proposed in 2001), our circuit leads to a high-performance software implementation for Rijndael encryption which offers significant speedup compared to previously reported implementations.