US Patent 7698357 Modular multiplication with parallel calculation of the look-ahead parameters

A device for calculating a multiplication of a multiplier and a multiplicand includes a first performer that performs an exact three operand addition and a second performer that performs an approximated operand addition and a calculator that calculates current look-ahead parameters using the approximated intermediate results. The first performer is further implemented to perform an exact three operand addition in the current iteration step using the exact intermediate result for the current iteration step and using the look-ahead parameters calculated for the current iteration step.