JPH01134689A - Portable electronic device - Google Patents

Abstract

PURPOSE:To prevent an erroneous rewriting or a deleting and to protect data without fail by adding information to identify whether the data can be rewritten or deleted to the data when the data are written to a memory part. CONSTITUTION:When the initial writing of the data is executed, according to a format to be composed of a data length 21, a head address 22, identifying information 23 and data 24, a data (a), for example, are written from a '0000' address with using a control element 11. At such a time, when a data length A from the head address '0000' to the data (a) is the data to be indispensable on the function of an IC card, the identifying element of '0', for example is added to the identifying information 23 so that the rewriting and deleting can not be executed and the data (a) are protected by the information 23. Next, when data (b), for example, are written from a '0010' address with the data length as B by using the element 11, a '1' identifying element is set to the information 23 in case that these data are rewritable and deletable data. Then, concerning following data (c) and (d), the writing is executed in such a way.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention is applicable to non-volatile data memory and CPU
The present invention relates to a portable electronic device called an IC card, which has a built-in IC (integrated circuit) chip having a control element such as a U.

(Prior Art) Recently, as a new portable data storage medium, an IC card with a built-in IC chip that has a non-volatile data memory (memo section) and a control element (control section) such as a CPU has been developed. ing. This type of IC card accesses a built-in data memory using a built-in control element, and performs input/output of necessary data in response to a request from an external device.

In addition, the data memory is divided into multiple areas.
It is designed to selectively access the target area.

Now, in such an IC card, when reading data from the data memory, the data is read out by setting the address where the data is stored and the data length from an external device. Furthermore, when writing data to the data memory, the data is written by giving an address and data to be stored from an external device. When rewriting or erasing existing data, the data identification information is the address and data length, so if you set the address incorrectly or set the data length beyond the range of the existing data, the data The problem was that it destroyed the .

(Problems to be Solved by the Invention) The present invention has been made in order to solve the above-mentioned problem in which the data in the memory section is accidentally rewritten or erased and the data cannot be protected. An object of the present invention is to provide a portable electronic device that can prevent data in a memory section from being erroneously rewritten or erased, and can reliably and securely protect data.

[Structure of the Invention] (Means for Solving the Problems) The portable electronic device of the present invention, when writing data to a memory section, determines whether the data can be rewritten or erased. The device is equipped with means for adding identification information indicating the identity of the user.

(Function) When writing data to the memory section, by adding identification information indicating whether or not the data can be rewritten or erased, the data can be rewritten or erased. By referring to the identification information added to the data section, it is possible to prevent the data from being erroneously rewritten or erased, and the data can be reliably protected.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 4 schematically shows the configuration of an IC card as a portable electronic device according to the present invention, including a control element (for example, a CPU) 11 as a control section, and an erasable nonvolatile data memory (memory section). 12, program memory 13,
and a contact section 14 for electrically communicating with a terminal device (not shown), among which the portion within the broken line (control element 11, data memory 12,
The program memory 13) is composed of one IC chip (or a plurality of IC chips) and is embedded within the IC card body. The program memory 13 is composed of, for example, a mask ROM, and stores a control program for the control element 11 and the like. The data memory 12 is used to store various data, and is composed of, for example, an EEPROM.

The data memory 12 is divided into a plurality of areas, as shown in FIG. 2, for example, and each area has a plurality of data blocks 20. ...are collectively defined. One data block 20 has a format, for example, as shown in FIG. 1, including a data length 21 indicating the length from the start address to the data section, a start address 22, and identification information 23 indicating whether rewriting and erasing are possible. , and data 24.

The initial data write operation in such a configuration will be explained. According to the format shown in FIG. 1, the control module 11 writes data a, for example, from address ro O00J. At this time, as shown in Figure 2, the first address r0000
The data length from address J to data a is rAJ, and since data a is essential for the functionality of this IC card, an identifier such as "0" is set in the identification information 23 so that it cannot be rewritten or erased. .

Therefore, data a can be protected by this identification information 23.

Next, the control element 11 writes, for example, data b from address "0010". At this time, as shown in Figure 2, the data length from the first address, address ro 010J to data b is rB.
J, and data b can be set freely depending on the use of this IC card, so an identifier such as "1" is set in the identification information 23 so that the data can be rewritten and erased. b can be freely rewritten and erased using this identification information 23.

Data c and d are also stored as shown in FIG. 2 according to the format shown in FIG. 1, and one area is defined by collecting these data.

Next, a data rewriting or erasing operation will be explained. For example, in order to rewrite data a in area 1 shown in FIG. 3, control element 11 reads out data a, and then writes data a' for rewriting according to the data length and start address of data a. is received from an external terminal device (not shown) and stored in a built-in RAM (not shown).

Then, the control element 11 determines whether to rewrite or erase the data based on the identification information 23 of the data a in the data memory 12. In data a, identification information 2
3 is "0", that is, data cannot be rewritten or erased. Therefore, the control element 11 transmits response data indicating that rewriting and erasing are not possible to the terminal device, and data a
remains as it is.

Next, data b' is rewritten with data b using the same method as data a' described above.

In this case, since the identification information 23 of data b is "1", that is, the data can be rewritten and erased, the control element 11 determines that the data can be rewritten and erased, and
The data b' stored in the memory is updated (rewritten) starting from address ro 010J where data b is stored.

Also, in the data erasing operation, the control element 11 makes a judgment by referring to the identification information 23 of the data to be erased, and determines the processing.

In this way, when writing data to the data memory, by adding identification information to the data that indicates whether the data can be rewritten or erased, the data can be easily rewritten or erased. By referring to the identification information added to the data, it is possible to prevent data from being accidentally rewritten or deleted.
Data can be reliably protected.

In the above embodiment, an IC card is used as an example of a portable electronic device, but the present invention is not limited to a card-shaped device, and may be a block-shaped or pencil-shaped device, for example.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to prevent data in the memory section from being erroneously rewritten or erased;
A portable electronic device that can reliably protect data can be provided.

[Brief explanation of the drawing]

The figures are for explaining one embodiment of the present invention. Figure 1 is a diagram showing an example of the format of a data block when writing to the data memory, and Figure 2 is a diagram explaining the configuration of the data memory and an example of data writing. 3 is a diagram for explaining an example of rewriting data in data memory, and FIG. 4 is a diagram for explaining an example of data rewriting of data memory.
FIG. 2 is a block diagram schematically showing the configuration of a card. 11... Control element (control unit), 12...
・Data memory (memory section), 13...Program memory, 20...Data block, 21
...Data length, 22...Start address, 23...Identification information, 24...Data. Applicant's agent Patent attorney Takehiko Suzue

Claims (3)

[Claims] (1) A portable electronic device that has a memory section for storing data and a control section for reading and writing data to the memory section, and selectively performs input/output from the outside; A portable electronic device characterized by comprising means for adding identification information indicating whether or not the data can be rewritten or erased to the data when writing data to the memory section. (2) The portable electronic device according to claim 1, wherein the memory section is a nonvolatile memory. (3) The portable electronic device according to claim 1, wherein the control section is a CPU (Central Processing Unit).