Concealment calculation device, concealment calculation method and concealment calculation program

摘要

To provide a secret calculation device, capable of generally performing a secret calculation of a two variable function, a secret calculation method, and a secret calculation program.SOLUTION: A secret calculation device 1 comprises: a storage part 20 that stores a coefficient of a first polynomial expression obtained by defining a functional value in accordance with a first variable number when a second variable number of two variable functions is a numeric constant by a polynomial interpolation; an input part 11 that receives each input of a first ciphertext and a second ciphertext, which are obtained by coding the first variable value and the second variable value with a homomorphic encryption scheme, respectively; a secret exponential calculation part 12 that performing exponential operation of the first ciphertext; a secret function calculation part 13 that calculates a value of a first polynomial expression as using the second variable number as a constant number by an inner product of a coefficient of the first polynomial expression and the exponential calculation of the first ciphertext; a secret equal mark calculation part 14 that calculates by the ciphertext a determination value which is 0 when a plaintext and a constant value before the encryption of the second ciphertext are different; and an output part 15 that outputs the value of the two variable functions by totally summing product of a calculation result by the secret function calculation part 13 in each constant number and the calculation result by the secret equal mark calculation part 14.SELECTED DRAWING: Figure 1