SECRET COLLECTIVE APPROXIMATION SYSTEM, SECRET CALCULATION DEVICE, SECRET COLLECTIVE APPROXIMATION METHOD, AND PROGRAM

摘要

In the present invention, a calculation time period is reduced without decreasing approximate accuracy when a complex function is calculated by secret calculation. A secret collective approximation system (100) calculates a secret sentence [z] of an approximate value z of a function value y satisfying y_j=f(x_j), by using a secret sentence [x] of a value x as input. "g" is defined as a polynomial for approximating sections obtained by dividing a function f into m sections. For each of integers j in the range of 1 to n, a parameter acquisition unit (11) acquires a secret sentence [a] of a parameter a corresponding to the value x by defining a_j as a parameter p_i corresponding to a section R_i in which a value x_j is included. A polynomial calculation unit (12) calculates a polynomial g([x],[a]) by using, as input, the secret sentence [x] of the value x by use of the secret sentence [a] of the parameter a, thus acquiring the secret sentence [z] of the approximate value z for the function value y.