By storing an authenticator created from a data file in a secure area usually unaccessible, the alteration of the data file can be detected. Furthermore, by designating the data file as a main-file and creating authenticators from various kinds of sub-files related to the main-file, the size of the secure...http://www.google.com.hk/patents/US6345360?utm_source=gb-gplus-share專利 US6345360 - Apparatus method and computer readable storage medium with recorded program for managing files with alteration preventing/detecting functions
