Fast Modular Multiplication for E-Commerce Cryptosystem

The performance of the modular multiplication is the core arithmetic of the RSA cryptosystem for e-commerce security. In this paper we present a novel technique for modular multiplication by performing complements on the multiplicand and partitioning the key size of the multiplier. By applying the modular arithmetic and complement technique to the Montgomery algorithm, we propose an efficient modular multiplication method that requires exactly 50% multiplications comparing to Lee-Jeong-Kwon´s algorithm.