A is a number stored in the memory of the computer, R' is the inverse of R where R???R' mod N=1, R is a number slightly larger than N and R=2n, and N=2n-1 +2n-2 ???2n-2 + . . . +a1 ???21 +a0 20, a second mode modular arithmetic A???B???R' mod N, where B is a number stored in the memory of the computer, and a third mode modular arithmetic A???R' mod N; and a timing/control program for instructing