An efficient signed digit montgomery multiplication for RSA

In this paper we present an efficient Montgomery multiplier using the signed digit number representation suitable for modular exponentiation, which is the main operation of RSA. The multiplier consists of one level of signed digit adder plus multiplexer through a precomputation. We design the multiplier with the improved signed digit adder using SAMSUNG STD 130 0.18μm 1.8 V CMOS Standard Cell Library and compare to multipliers with other previous adders. The proposed modular multiplier can be applied to public key cryptosystems based on integer arithmetic such as RSA, DSA or ECC.