Card-type storage medium protecting data stored in its memory by interrupting an existing transaction after a predetermined permissible number of accesses

In a card-type storage medium having a storage unit having a data area keeping a data file therein and a directory area keeping control information about the data file in said data area therein and a control unit managing the data file in said data area in said storage unit on the basis of the control information in said directory area in said storage unit, the improvement comprising:

• said directory area in said storage unit being set beforehand with a permissible number of file accesses for said data file in one transaction;
• said control unit comprising:
• a counting means for counting a number of file accesses to said data file after an authentication process and after a start of a transaction when said transaction is started with an external apparatus;
• a comparing means for comparing the number of file accesses counted by said counting means with said permissible number of file accesses set beforehand in said directory area in said storage unit;
• and
• an error judging means for determining that an error has occurred if said number of file accesses exceeds said permissible number of file accesses as a result of comparison by said comparing means, and for interrupting said transaction.

In a card-type storage medium having a storage unit having a data area keeping a data file therein and a directory area keeping control information about the data file in said data area therein and a control unit managing the data file in said data area in said storage unit on the basis of the control information in said directory area in said storage unit, the improvement comprising:

• said directory area in said storage unit being beforehand set with a permissible file access period for said data file in each transaction;
• said control unit comprising:
• a timer means for measuring a file access period to said data file after an authentication process and after a start of a transaction when said transaction is started with an external apparatus;
• a comparing means for comparing the file access period measured by said timer means with said permissible file access period set beforehand in said directory area in said storage unit;
• and
• an error judging means for determining that an error has occurred if said file access period exceeds said permissible file access period as a result of comparison by said comparing means, and for interrupting said transaction.

In a card-type storage medium having a storage unit having a data area keeping a data file therein and a directory area keeping control information about the data file in said data area therein and a control unit managing the data file in said data area in said storage unit on the basis of the control information in said directory area in said storage unit, the improvement comprising:

• said directory area in said storage unit being beforehand set with a permissible number of file accesses and a permissible file access period for said data file in one transaction;
• said control unit comprising:
• a counting means for counting a number of file accesses to said data file after an authentication process and after a start of a transaction when said transaction is started with an external apparatus;
• a timer means for measuring a file access period to said data file after the authentication process and after the start of said transaction;
• a first comparing means for comparing the number of file accesses counted by said counting means with said permissible number of file accesses set beforehand in said directory area in said storage unit;
• a second comparing means for comparing the file access period measured by said timer means with said permissible file access period set beforehand in said directory area in said storage unit;
• and
• an error judging means for determining that an error has occurred if said number of file accesses exceeds said permissible number of file accesses as a result of comparison by said first comparing means or if said file access period exceeds said permissible file access period as a result of comparison by said second comparing means, and for interrupting said transaction.