| 摘要 |
PROBLEM TO BE SOLVED: To speedily perform ciphering and deciphering processes by executing a preprocess part and storing the obtained preprocess value in a memory in relation with key information when the key information is stored in the memory. SOLUTION: The IC card 10 is equipped with a ROM 12 as a read-only memory, a RAM 14 as a volatile memory, an EEPROM 16 as a nonvolatile memory which is rewritable at any time, and a CPU 18 which accesses those memories 12 and 14. Further, the IC card 10 is equipped with an I/O interface 20 for communicating with a reader writer 22. Then a data converting program of the IC card 10 has the preprocess part which performs a process that does not depend upon the contents of data to be ciphered and deciphered and a primary process part which performs a process that depends upon the contents of the data. Here, when the key information is stored in the memory, the preprocess part is executed and the obtained preprocess value is stored in the memory while related to the key information. |
