In this paper, a new efficient VLSI architecture to compute modular exponentiation and modular multiplication for Rivest-Shamir-Adleman (RSA) public-key cryptosystem is proposed. We modify the conventional H-algorithm to find the modular exponentiation. By this modified H-algorithm, the modular multiplication steps for n-bit numbers are reduced by 5n/18 times. For the modular multiplication a modified L-algorithm (LSB first) is used. In the architecture of the modified modular multiplication the iteration times are only half of Montgomery's algorithm and the H-algorithm. The proposed architecture for the RSA public-key crypto-system has a data rate of 146 kb/s for 512-b words with a 200-MHz clock rate.
淡江理工學刊=Tamkang journal of science and engineering 7(4)，頁241-250