Abstract: Montgomery Modular Multiplication is a method for performing fast modular multiplication. Montgomery Modular Multiplication is used for encryption process in Public Key Cryptography.This paper proposes a Semi Carry Save (SCS) based Montgomery Modular Multiplication, with high speed performance. One Carry Save Adder(CSA) is used to avoid carry propagation at each addition operation. The CSAis reused for operand pre-computation and format conversion leading to a short critical path delay. Proposed Montgomery modular Multiplier is implemented using VHDL language in Xilinx software. The proposed multiplier is then compared with one of the existing Montgomery multiplier in terms of area, delay and power.

Keywords: Carry Save Adder, Montgomery Modular Multiplication, Semi Carry Save , Public Key Cryptography.