Data storage, the management server, the integrated circuit, a data update system, home appliances, data updating method, encryption method, and decryption key generation method

摘要

Provided is a data storage device capable of safely and effectively updating software of a home electric apparatus. In the home electric apparatus (100) in which currently used data is to be updated to new data, a reception unit (140) receives encrypted new data and a serial number of data to be updated. A key generation unit (112) generates a key by executing a predetermined irreversible calculation on the unique information correlated to the currently used data by a number of times based on the serial number of the data to be updated. An update unit (113) decrypts the new data by using the key.