A measurement device measures vital data, encrypts the vital data using an encryption key to generate encrypted vital data, and generates, from a decryption key of the vital data, two pairs of a first share FSD and a second share SSD which enable reproduction of the decryption key. The measurement device generates an encrypted second share by encrypting the second share SSD. The measurement device transmits the encrypted vital data, the first share FSD, and the encrypted second share to a server device via an intermediate device.
