| 摘要 |
PURPOSE:To avoid a case where the structure of an inside memory area is recognized easily from the outside and to improve the security, by giving access to apparently a single area from the outside in case an access is given to a single area within a data memory or giving accesses to plural areas. CONSTITUTION:A CPU 3 reads an area main number #01 corresponding to a code aA of the input data out of a specific area 4a as the input data and decides an access area as a data memory area 4b to confirm just a single area to receive an access for the input data. It is recognized as if the input data given access apparently to a single area when the data is supplied to the CPU 3 within an IC card 1. Thus the input data can be easily processed when an aces is given to a single area and also when the access is given to plural areas. Furthermore, it is not required to consider the structure of a data memory within the IC card at the side of an external device when access is given to the area. Thus it is impossible to recognize easily the structure of the inside memory area from the outside. This improves the security.
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