Modulo M multiplication-addition: algorithms and FPGA implementation

Variants of a modular multiplication algorithm originally due to Koc$80 and Hung (1990), that are especially suited for FPGA implementation, and that allow to compute (XY+W) modulo M, where there is no need to know M at design-time, are presented. Some results obtained on a Xilinx Virtex-E FPGA are shown.