IC card having improved security checking function

An IC card comprising:

• data storage means for prestoring a plurality of data, said plurality of data being respectively associated with a plurality of data identification codes;
• identification code storage means for prestoring a plurality of second identification code which permit selective use of at least some of the data stored in said data storage means;
• reference information storage means for prestoring:
• (1) said plurality of data identification codes and (2) reference information respectively associated with each data identification code directly indicative of those second identification codes stored in said identification code storage means which are authorized to use the data respectively associated with a data identification code;
• selecting means for selecting, when at least one second identification code is externally applied to said IC card, a corresponding second identification code stored in said identification code storage means;
• referencing means for referencing, when a data identification code is externally applied to said IC card, one or more second identification codes indicated in the reference information associated with said externally applied data identification code;
• and
• determining means for determining whether or not a second identification code indicated by said reference information associated with said externally applied data identification code is also selected by said selecting means and, if so, permitting use of the data.

A method of operating an IC card comprising the steps of:

• receiving at least one externally applied identification code;
• comparing said at least one said externally applied identification code with a plurality of internally stored identification codes for correspondence and identifying each of the internally stored identification codes which corresponds to said at least one externally applied identification code;
• receiving at least one externally applied data identification code;
• selecting data access information corresponding to said at least one externally applied data identification code, said data access information establishing at least one correspondence condition which must exist between one or more externally applied identification codes and one or more internally stored identification codes in order to obtain access to stored data corresponding to said externally applied data identification code;
• and
• permitting access to said stored data when the correspondence condition established by said data access information is identified in said comparing step.