| 摘要 |
PROBLEM TO BE SOLVED: To provide a prepaid card system for preventing the use of a prepaid card forged by copy or the like. SOLUTION: At the time of recording variable information updated according to the amount of spent money in a prepaid card 6, a reading/writing device updates the variable information of a variable area EA1 in which projecting and recessing parts are formed, and obtains the featured data of the new updated variable information, and includes the featured data in variable information to be recorded in a variable area EA2, and enciphers and records the variable information by using the obtained featured data as a key. After the completion of the recording-update of the variable information in the variable areas EA1 and EA2, the reading/writing device obtains the featured data of the variable information of the variable area EA1 again, and checks whether or not the variable information of the variable area EA2 can be decoded, and checks whether or not the obtained featured data are made coincident with the featured data included in the variable information when the variable information can be decoded. |
