Efficient Design and Performance Analysis of a Hardware Right-shift Binary Modular Inversion Algorithm in GF(p)

For efficient hardware (HW) implementation of elliptic curve cryptography (ECC), various sub-modules for the underlying finite field operations should be implemented efficiently. Among these sub-modules, modular inversion (MI) requires the most computation; therefore, its performance might be a dominant factor of the overall performance of an ECC module. To determine the most efficient MI algorithm for an HW ECC module, we implement various classes of MI algorithms and analyze their performance. In contrast to the common belief in previous research, our results show that the right-shift binary inversion (RS) algorithm performs well when implemented in hardware. In addition, we present optimization methods to reduce the area overhead and improve the speed of the RS algorithm. By applying these methods, we propose a new RS-variant that is both fast and compact. The proposed MI module is more than twice as fast as the other two classes of MI: shifting Euclidean (SE) and left-shift binary inversion (LS) algorithms. It consumes only 15% more area and even 5% less area than SE and LS, respectively. Finally, we show that how our new method can be applied to optimize an HW ECC module.