Design methodology for Booth-encoded Montgomery module design for RSA cryptosystem

In this paper, a design methodology for the design of a Montgomery module is proposed. We summarize the result in pseudo C-like codes and call it Booth-encoded Montgomery modular multiplication algorithm. Using this algorithm, iteration number is reduced to about n/2 in each Montgomery operation. In addition, we apply the folding and unfolding techniques to shorten the critical path. Finally, we propose the 4 bit-digit-serial pipelined architecture to process RSA encryption/decryption in a more efficient way. The speed of the proposed algorithm is approximately 1.7 times that of most RSA VLSI designs based on original Montgomery modular multiplication algorithm.