Modular exponentiation using parallel multipliers

A field programmable gate array (FPGA) semi-systolic implementation of a modular exponentiation unit, suitable for use in implementing the RSA public key cryptosystem is presented. The design is carefully matched with features of the FPGA architecture, utilizing embedded 18×18-bit multipliers on the FPGA and employing a carry save addition scheme. Using this architecture, a 1024-bit modular exponentiation can operate at 90 MHz on a Xilinx XC2V3000-6 device and perform a 1024-bit RSA decryption in 0.66 ms with the Chinese Remainder Theorem.