Efficient multiplication beyond optimal normal bases

In cryptographic applications, the use of normal bases to represent elements of the finite field GF(2/sup m/) is quite advantageous, especially for hardware implementation. In this article, we consider an important field operation, namely, multiplication which is used in many cryptographic functions. We present a class of algorithms for normal basis multiplication in GF(2/sup m/). Our proposed multiplication algorithm for composite finite fields requires a significantly lower number of bit level operations and, hence, can reduce the space complexity of cryptographic systems.