A storage system in which a storage control apparatus writes data in each of divided areas defined by division of one or more storage areas in one or more storage devices, after encryption of the data with an encryption key unique to each divided area. When the storage control apparatus receives, from a management apparatus, designation of one or more of the divided areas allocated as one or more physical storage areas for a virtual storage area to be invalidated and an instruction to invalidate data stored in the one or more of the divided areas, the storage control apparatus invalidates one or more encryption keys associated with the designated one or more of the divided areas. In addition, the storage control apparatus may further overwrite at least part of the designated one or more of the divided areas with initialization data for data erasion.