17.1 INTRODUCTION

There are many excellent books on applied cryptography that explain the ideas discussed in this chapter such as finite Galois fields and the basic mathematical operations performed in them [101, 102]. It is assumed that the reader of this chapter is already familiar with these concepts and wants to know how the algorithms could be implemented in parallel hardware. A number of cryptographic algorithms (e.g., the Advanced Encryption Standard [AES], elliptic curve cryptography [ECC]) rely heavily on GF(2^m) multiplication [103]. All these algorithms require fast, inexpensive, and secure implementation of multiplication over GF(2^m). Therefore, the design of efficient high-speed algo­rithms and hardware architectures for computing GF(2^m) multiplication are highly required and considered. Hardware implementation techniques for GF(2^m) multiplier include traditional techniques [104, 105] and processor array (PA) techniques [106–108]. Traditional multipliers are not attractive since their hardware structures are irregular and could be quite different for different m values. Moreover, as m gets larger, the propagation delay increases, which causes unavoidable performance deterioration. On the contrary, PA multipliers do not suffer from the above prob­lems. They have regular structures consisting of a number of replicated basic cells. Furthermore, since each basic cell is only connected to its neighboring cells, signals propagate at a high clock speed [107]. In 1984, Yeh et al. [109] proposed a parallel-in parallel-out PA architecture to calculate AB + C in a general field GF(2^m). Since then, many PA multipliers have been proposed [106–108]. The main idea of this chapter is the PA design space exploration for GF(2^m)-based multipliers. This exploration results in different PA configurations. Among these configura­tions, we choose the fastest one to suit real-time applications. We made use of National Institute for Standards and Technology (NIST)-recommended irreducible polynomials, which makes our design secure and more suitable for cryptographic applications.