Conventionally, an encryption key for encrypting data to be backed up in a tape cannot be allocated for each logical data management unit. To solve the problem, provided is a storage system including: a disk storage device; a tape storage device in which a tape storage medium is loaded; and a controller for controlling the disk storage device and the tape storage device, in which the controller is configured to: generate, upon reception of a request for setting a tape group including one or more tape storage media, a first encryption key used for encrypting data stored in the tape group set by the request; and hold information for correlating the generated first encryption key with the tape group.