| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve the security function of an IC card by performing a prescribed error processing and preventing unauthorized access to a memory part at the time of detecting that a password stored in the memory part beforehand is not normally read. SOLUTION: This IC card 1 of a non-contact type can detect a state where a sense amplifier circuit part 7 is not operated, especially the operation stoppage state of the sense amplifier circuit part 7 by the decline of a power supply voltage supplied from an internal power supply circuit part 11, at the time of password collation by a control circuit part 10. Thus, whether or not the password stored in a nonvolatile memory part 6 beforehand is normally read is detected. From that, at the time of detecting that the password stored in the nonvolatile memory part 6 beforehand is not normally read, the prescribed error processing is performed and the unauthorized access to the nonvolatile memory 6 is prevented. Also, it is applied in the IC card of a contact type as well.</p> |
