PORTABLE ELECTRONIC DEVICE AND CONTROL METHOD THEREOF

摘要

A flag which is set to the on state when a process of writing data as a data file into a storage area which is permitted to be written only once results in failure is previously set in a data memory (14) of an IC card (1). When a flag of a to-be-written EF specified by a write binary command is set to the on state, a control element (11) of the IC card (1) compares received data to be written to the EF with data which is already written to the data storage area of the EF. Based on the comparison result, the control element (11) of the IC card (1) rewrites data in the storage area in which the compared data items do not coincide with each other into the received data.