Production process of an error correcting parameter associated with the implementation of modular operations according to the Montgomery method

摘要

The modulo (N) is loaded into a shift register (12) through a multiplexer (42) whose second input is connected to the output of the shift register (12). A second shift register (10) is loaded with (n) initialisation bits of zero through a second multiplexer (41). A subtraction circuit (27) receives the output from the second shift register (10) and the output from the first shift register (12) via a multiplexer (36) and then supplies a second subtraction circuit (40). A gate (43) is fed from the outputs of the two subtraction circuits and supplies a circuit (44) which stores the comparisons.