JPH0426923Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a card in which an integrated circuit (IC) containing an active element such as a microcomputer is embedded to hold various data such as identification, and in particular, an EEPROM (electronic memory card) is used as a memory element. Erasable and programmable read
(abbreviation for only memory).

As identification cards (referred to as IC cards) such as identification cards, credit cards, or bank cards, data cards that hold data using a magnetic recording method have been mainly used.

This magnetic recording type card is advantageous in certain applications, such as when bank cards are used to record deposit balances, as data can be rewritten relatively easily, but data tampering is not sufficiently prevented. However, there are problems in that it is difficult to protect data from magnetic contamination, which is likely to occur when the device is not portable, and that it may not be sufficiently reliable.

Therefore, in consideration of these points, an electronic circuit consisting of an integrated circuit (IC) element etc. is embedded in the card, data is stored in the electronic circuit, and the data is read out as necessary for use in identification etc. Data cards based on this technology have been proposed and are beginning to be put into practical use.

A data card with a built-in IC-based electronic circuit is called, for example, an IC card.
For example, as shown in the front view of FIG. 1 and the cross-sectional view of FIG.
This IC module 4 is provided with a contact terminal (electrode) 5 to enable electrical connection between an external circuit and an electronic circuit included in the IC module 4. It's getting old.

Further, the surface of the card base 2 is often provided with a pattern 6 made of predetermined characters or figures drawn with ink or the like, and to protect these, a protective layer 7 made of a suitable transparent plastic or the like is applied. are provided, and together form the IC card 1.

Note that 8 is a striped layer of magnetic material, which is provided so that it can be used as a magnetic recording data card, and is not particularly necessary for an IC card.

The electronic circuits installed in the IC module 4 include various memory circuits based on LSI (Large Scale Integrated Circuits) and data processing circuits such as microcomputers.
When set in a specified check device, an electrical connection between the electronic circuit mounted on the IC module 4 and an external data processing circuit is established via the contact terminal 5, and the IC module 4 performs an electrical connection according to the data given from the external circuit. Predetermined data is output from the electronic circuit of the IC card 1, and serves functions such as identification.

This IC card is difficult to tamper with data, is resistant to changes in the magnetic environment, and can easily increase the amount of data that can be stored, so it is widely used not only as an ID card but also for general data storage. It is starting to be adopted.

By the way, the configuration of the IC module 4 in such an IC card has traditionally been one that uses PROM (Programmable Read Only Memory) for storing transaction data, as shown in Figure 3, for example. was often used. In the figure, 40 is a CPU (Central Processing Unit), 41 is a ROM (Read Only Memory), and 42 is a PROM.
These are configured to be connectable to an external device via the respective terminal pieces 5 ₁ to 5 ₆ of the contact terminal 5, and the data written in the PROM 42 is read out and used for identification purposes.

However, in an IC card with a built-in IC module 4 as shown in Fig. 3, the PROM
Generally, it is not possible to rewrite the data written on the IC card, so if there is a change in the data that should be read, a new IC card should be used instead of the old IC card.
Since it is necessary to prepare an IC card and write new data to its PROM 42 before use, it is difficult and uneconomical to reuse an old IC card.

Therefore, even if the data changes, it will remain as it is.
In order to enable the reuse of IC cards, as shown in Figure 4, a
IC cards that use EEPROM43 have come into use.

According to the IC card using this EEPROM 43, when there is a change in the data to be read,
It is only necessary to write new data after erasing the previous data, and since it can be reused any number of times, it has the advantage of being extremely economical.

However, in IC cards using such EEPROM, the fact that the data can be easily erased may act as a disadvantage in some cases.
There is a drawback that there is a risk of accidentally erasing data that you want to keep, and it is difficult to sufficiently increase the reliability of the IC card due to the loss of necessary data. Ta.

The purpose of the present invention is to eliminate the drawbacks of the prior art described above, take full advantage of the advantages of an IC card using EEPROM, and sufficiently prevent the occurrence of a situation in which even necessary data is accidentally erased. It is easy to provide an IC card that can be used.

To achieve this purpose, the present invention provides a specific memory area in the EEPROM built into the IC card that is independent of the general transaction data write area, so that the data erase input to the EEPROM is transferred to the IC card. When given,
First, data is read from this specific area, and when the content of this data is in a predetermined state,
The present invention is characterized in that the data erasing operation for the EEPROM is prohibited, and in order to truly erase the data in the EEPROM, it is necessary to rewrite the data in a specific area of the EEPROM in advance.

Embodiments of the IC card according to the present invention will be described below with reference to the drawings.

First, the IC module 4 provided in the IC card in one embodiment of the present invention is the same as the conventional example shown in FIG. 4, except that a part of the memory area of the EEPROM 43 has a specific Area A
(first memory area) is provided, general data is not written to this area, and
Even when a data erasing command to the EEPROM43 is input from an external device, it will immediately erase the data.
When an erase command is input instead of erasing the EEPROM 43, data is first read from a specific area A of the EEPROM 43, and it is determined whether data erasing operation for the EEPROM 43 is prohibited according to the contents of the read data. This differs from the conventional example in that the ROM 41 stores a program that executes the data erasing operation on the EEPROM 43 only when the data is determined and is not prohibited. In addition, B represents the general data storage area (second memory area) necessary for the IC card, such as for identification, and M represents the
This represents the entire memory area of the EEPROM 43.

Next, the operation of this embodiment will be explained with reference to the flowchart of FIG.

After a data erasing command is input from the external device in step, the specific area A of the EEPROM 43 is accessed and the data stored there is read out. Next, the process advances to step 1, and the data read in step is examined to determine whether or not the content indicates erasure prohibition.

If the result in step is NO, proceed to step to output an erasable code, then execute data erasure of the EEPROM 43 in step, and then exit from this flow.

On the other hand, if the step result is YES,
Proceed to the step, output the erasure prohibition code, and then exit from this flow.

Therefore, according to this embodiment, even when the EEPROM 43 is accessed by an external device or the like and a command to erase the data stored therein is input, the command is immediately executed in response to the instruction to erase the data stored therein.
Rather than erasing the data in the EEPROM 43, the data stored in a specific storage area A of the EEPROM 43 is first read, and the content of this read data is transferred to the EEPROM 43.
This IC will erase data from the EEPROM43 only after confirming that it does not indicate prohibition of data erasure in step 3.
When the data stored on the card requires saving, the EEPROM 43
It is only necessary to store data indicating erasure prohibition in a specific storage area A of It is possible to completely prevent data from being erased and lost.

Note that when the data written to the IC card according to this embodiment becomes unnecessary and new data needs to be written,
It is sufficient to access the specific area A of the EEPROM 43, rewrite the data stored therein indicating that data erasure is prohibited, and then input a data erasure command.

Therefore, the data indicating prohibition of data erasure that should be stored in the specific area A of the EEPROM 43 is as follows:
It needs to be rewritable when accessed by an external device.

For example, the EEPROM 43 is generally in hexadecimal code, and its initial state, that is, the state where this EEPROM is shipped from a specified manufacturer and is incorporated into an IC card as it is, or , Once the data has been erased, the state is often a hexadecimal code such as (FF) ₁₆ , which means that all bits are in the erased state.
In EEPROM, writing data is the binary code (1111 1111) corresponding to the hexadecimal code of FF _16. The value of ₂ (1). The arbitrary value of each bit of ₂ is written as the binary code (0) _2.
In this case, when all data has been rewritten, the data state becomes (00) ₁₆ , and no further data can be rewritten. become. Therefore, in order to enable data rewriting, the original data must have a hexadecimal code other than (00) ₁₆ .

Therefore, in this embodiment, the above-mentioned specific area A
In the case of a hexadecimal code, (FF) ₁₆ is used as the data representing the prohibition of erasure of data that should be stored in
The data is the same as when this EEPROM 43 is in the erased state. That is, in this embodiment, the data for which the result is YES in the step of FIG. 6 is configured so that the hexadecimal code is (FF) ₁₆ .

Then, the specific area A of this EEPROM43
If data (FF) ₁₆ is written to the IC card 1, even if a data deletion command is input to the IC card 1 from an external device, the IC card 1 will only output a signal representing the deletion prohibition code. The data is not erased, thus eliminating the risk of losing data that should be saved.

When the data stored in the IC card 1 is no longer needed, you can rewrite the data (FF) ₁₆ stored in the specific area A of the EEPROM 43 to, for example, (EO) ₁₆ , and the subsequent data In response to the input of the erase command, all data stored in the EEPROM 43 including the data in the specific area A can be erased and returned to the erased state (FF) ₁₆ , so the IC card 1 can be used for new data. It can be reused as

By the way, the data that is stored in this specific area A and indicates that deletion of data is prohibited, that is, the data that results in YES in the step of FIG. 6, is as follows.
The data expressed in the initial state of the EEPROM 43 may be used as is. For example, in the above example, it is set to (FF) ₁₆ .

If this is done, the IC card 1 will be in a state where data deletion is prohibited at the beginning of its use and immediately after the data has been deleted, without requiring any special processing for the specific area A. It is possible to obtain an IC card that is free from the risk of data loss due to erroneous operation.

In addition, in this case, the data that should be written to the specific area A in order to cancel the data erasure prohibition can be any writable data, making the process easier. .

As explained above, according to the present invention, even in an IC card that is equipped with an EEROM for data storage and can be used repeatedly, there is no risk of necessary data being accidentally erased and lost. Since data can be erased whenever necessary, it is possible to eliminate the drawbacks of the prior art and easily provide a highly reliable and economical IC card.

[Brief explanation of the drawing]

Figure 1 is a front view showing an example of an IC card, Figure 2 is a front view showing an example of an IC card.
Figure 3 is a circuit diagram showing an example of an IC module in a conventional IC card, Figure 4 is a circuit diagram showing an example of an IC module using EEPROM, and Figure 5 is a circuit diagram of an IC module according to the present invention. of
FIG. 6 is a conceptual diagram showing an embodiment of a storage area in an EEPROM, and a flow chart showing the operation of an embodiment of the present invention. 1...IC card, 2...card base, 3...
Recess, 4...IC module, 5...Contact terminal,
40... CPU (Central Processing Unit), 41... ROM (Read Only Memory), 43... (Electrically Erasable and Programmable ROM).

Claims (1)

[Scope of utility model registration request] An active element having an electrical signal processing function consisting of a microcomputer, and a first memory area and a second memory area are set in the memory area.
a first processing function that directly enables an access operation to a first memory area of the storage element; and a first processing function that responds to the content of data read from the first memory area of the storage element. a second memory area for determining permission or prohibition of erasing operations for the first and second memory areas of the memory element;
In an IC card in which a processing function is set as part of the processing function of the active element, the data read from the first memory area of the storage element is the same data as when the EEPROM is in an erased state. The IC card is characterized in that the second processing function is configured such that an erasing operation for the memory area of the storage element is permitted only when the memory area of the storage element is erased.