| 摘要 |
PROBLEM TO BE SOLVED: To improve security by defining the reloading or illegal copy of data as meaningless information by enciphering data through a data processing part with the number of times of transactions under host management as a key. SOLUTION: When starting the transaction, data on a recording medium are read by a recording medium information reading/writing part 10 and temporarily saved in a memory area 13 by a main control part 11 and a memory control part 12. The main processing part 11 requests the notice of a decipher key (the number of times of transactions) managed by a host to the host and with the number of times of transaction reported from the host as a key, card data temporarily saved in the memory area 13 are deciphered and saved in a memory area 14. The main processing part 11 enciphers the data in the memory area 14 corresponding to the key, which is reported from the host, utilizing the number of times of transactions (key different from the time of deciphering adding '1' to the number of times of transactions, for example,), saves them in a memory area 15, records these data on the card recording medium and returns the card. |
