A search-instruction-data creating unit issues a search request command to a peripheral device, and creates search instruction data including a predetermined field that stores supplementary information. A search-instruction-data transmitting unit transmits the search instruction data to the peripheral device. A security-reference-information transmitting unit transmits, to the peripheral device, security reference information serving as the supplementary information. A search-report-data generating unit generates a search report data upon receiving the search instruction data. A search-report-data transmitting unit transmits the search report data to a host device. A supplementary-information extracting unit extracts the supplementary information from the predetermined field of the search instruction data. An authenticating unit authenticates an access authority for accessing a storage medium from the host device, based both on security master information stored in the storage medium and on the security reference information that is received from the host device.