An information processingsystem is provided, wherein a generator-side apparatus generates a first verification value from structure data and weighting factor data of an NN (neural network) and transmits signature data in which the first verification value is encrypted with a private key to a user-side apparatus, and the user-side apparatus generates a second verification value from structure data and weighting factor data of the NN stored therein, decrypts the signature data received from the generator-side apparatus with a public key corresponding to the private key to acquire the first verification value, and determines whether the NN stored therein is falsified or not by comparing the first verification value with the second verification value.