Patent ID: 7562201

Claim:
A recording device for recording data on a recording medium, comprising: a read/write module which reads and writes data on a recording medium, said read/write module having electric power being supplied by an external power source; a battery-built-in clock which has a built-in battery and a clock function; an input/output interface for inputting data from outside and outputting data to outside; and a controller for controlling said read/write module and said input/output interface, wherein: said recording medium includes an ordinary data area for writing ordinary data and an expiration time data area for writing an expiration time of said ordinary data, and said controller performs control to alter ordinary data read from said recording medium into invalid data and output said invalid data, when said ordinary data is read and said expiration time written in said expiration time data area has passed based on a time calculated by the clock function of said battery-built-in clock, and said controller performs control to delete said ordinary data on said recording medium at arbitrary timing later than said expiration time.