SECRET QUOTIENT TRANSFER DEVICE, SECRET BIT RESOLUTION DEVICE, SECRET MODULUS CONVERSION DEVICE, SECRET QUOTIENT TRANSFER METHOD, SECRET BIT RESOLUTION METHOD, SECRET MODULUS CONVERSION METHOD, AND PROGRAM

摘要

To provide a secret quotient transfer device that can reduce the communication cost. On the assumption that u denotes a natural number and represents a boundary value, m denotes an integer that satisfies a relation m ≤ 2^u, i denotes an integer from 0 to m-1, a plain text a is an integer that is equal to or greater than 0 and smaller than an arbitrary modulo p, the integers a and 0 are congruent modulo 2^u, and the plain text a is expressed as a sum of m sub-shares x₀, ..., x_m-1, the secret quotient transfer device computes a quotient q of the division of a total sum a_Z of the sub-shares by p according to q = E(i m)xⁱ mod 2^u.