Efficient VLSI Implementation of Modulo 2n 1 Addition and Multiplication

New VLSI circuit architectures for addition and multiplication modulo 2 1 and 2 1 are proposed that allow the implementation of highly efficient combinational and pipelined circuits for modular arithmetic. It is shown that the parallel-prefix adder architecture is well suited to realize fast end-around-carry adders used for modulo addition. Existing modulo multiplier architectures are improved for higher speed and regularity. These allow the use of common multiplier speed-up techniques like Wallace-tree addition and Booth recoding, resulting in the fastest known modulo multipliers. Finally, a high-performance modulo multiplier-adder for the IDEA block cipher is presented. The resulting circuits are compared qualitatively and quantitatively, i.e., in a standard-cell technology, with existing solutions and ordinary integer adders and multipliers.