A storage device includes a storage unit that stores key information. The storage device also includes an input/output unit that inputs a converted command. Further, the storage device includes an extractor that extracts attached information from the converted command inputted, reads out, from an address according to the attached information, the key information from the storage unit, and performs an inverse data conversion corresponding to a data conversion on the converted command, using the key information, to extract command information and address information. In addition, the storage device includes an output controller that, only when the command information is equivalent to predetermined information, reads out and outputs storage data from an address of the storage unit through the input/output unit, the address of the storage data indicated by the address information extracted by the extractor.