SECRECY ANALYSIS DEVICE, SECRECY ANALYSIS SYSTEM, SECRECY ANALYSIS METHOD, AND SECRECY ANALYSIS PROGRAM

摘要

This secrecy analysis device (60) accepts a ciphertext c'_i obtained by encrypting a message x_i and a secret key sk_y having a value set for y as inputs, and acquires a ciphertext c_i which is obtained, using an encoding token etk, by encrypting the ciphertext c'_ithrough a multiple-input functional encryption that outputs an arithmetic result when the message x_i and the value y are inputted in function f. The secrecy analysis device (60) generates the ciphertext c'_i by decoding the ciphertext c_i using a decoding token dtk, and computes an arithmetic result by decoding the ciphertext c'_i using the secret key sk_y.