A device includes a memory which stores a program, and a processor which executes, based on the program, a procedure comprising establishing a session with a request source when a request for a service, made to a second providing source, has been received from the request source, the second providing source providing the service based on data stored in a first providing source; and when an inquiry about whether to transmit the data to the second providing source has been received from the first providing source, notifying, so as to encrypt a mask range of the data, the first providing source of session information indicating the session established with the request source and notifying the request source of the session information so as to decrypt the encrypted mask range of data based on the session information.