JP3195122B2 - Check method of instruction format given to IC card - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an instruction format checking method for checking the format of an instruction given from a reader / writer device to an IC card.

[0002]

2. Description of the Related Art As a new information recording medium replacing a magnetic card, an IC card has attracted attention. In particular, CPU
An IC card with a built-in is expected to be used in various fields because of its high security. Generally I
The C card has three types such as RAM, ROM, and EEPROM.
There are various types of memories, all of which are accessed by the built-in CPU. The transfer of data to and from the IC card is performed by a reader / writer device. When a predetermined command is given from the reader / writer device to the IC card, the command is executed by the CPU in the IC card. For example, in the case of a data write command, data given from the reader / writer device to the IC card is written in the memory in the IC card, and in the case of a data read command, data read from the memory in the IC card is used. Is transferred to the reader / writer device.

A command given from a reader / writer device is as follows:
It is described in a predetermined format. IC
When the CPU built in the card receives an instruction described in a correct format, the CPU can execute the instruction correctly. However, when an instruction described in an incorrect format is given, the instruction cannot be executed correctly, an unexpected process is performed, and an undesirable situation may occur. For this reason, before executing an instruction given from the reader / writer device, the IC card checks whether or not the instruction is described in a correct format.

[0004]

The emphasis on portability of IC cards is imposed on their physical size. For this reason, the storage capacity of the built-in memory is also greatly limited, and it is required to make the capacity of the built-in program as small as possible. On the other hand, in order to realize a multifunctional IC card, the number of instructions given from the reader / writer device tends to increase. As described above, it is necessary to check the format of the instruction given from the reader / writer device before execution, but as the number of instructions increases, the built-in program required to perform this check increases. Capacity increases.

Accordingly, an object of the present invention is to provide a method of checking an instruction format given to an IC card which can reduce the capacity of a program built in the IC card.

[0006]

[Means for Solving the Problems]

(1) The first invention of the present application is a checking method for checking a format of an instruction given from a reader / writer device to an IC card. In the check method, a command used only until the IC card is issued is checked on the reader / writer device side. Instructions to be used even after the IC card is issued are checked in the IC card.

(2) In the second invention of the present application, in the check method according to the first invention, a command for creating a directory and a command for defining a key are checked on the reader / writer device side. Things.

[0008]

[Operation] When an IC card is used in the general society, it is necessary to perform an "issuing process". Before and after this issuance process, the reliability of the reader / writer device connected to the IC card differs greatly. That is, after the issuing process, I
The exclusive right to the C card is attributed to a specific individual,
There is also a risk of being exposed to wrong or incorrect usage. Therefore, there is a possibility that the device will be inserted into a reader / writer device that is originally not compatible. On the other hand, before the issuance process, the handling of IC cards is left to the issuer with the appropriate authority.
The risk of exposure to incorrect or unauthorized usage is very low. Therefore, it may be considered that there is no possibility of being originally inserted into an incompatible reader / writer device.

The present invention pays attention to such a point, and performs a format check on a reader / writer device side for an instruction used only before an IC card issuance process, and
The format check inside the card is omitted. As described above, before an IC card issuance process, various processes are performed by an issuer having an appropriate authority. Therefore, it may be considered that only a correct reader / writer device is used. Therefore, if the command format check is performed in the correct reader / writer device, it is not necessary to perform the check inside the IC card. As described above, by omitting the check processing program for an instruction used only before the IC card issuance processing from within the IC card, it is possible to reduce the program capacity.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a block diagram showing a state where a general IC card 10 is connected to a reader / writer device 20. IC
In the card 10, an I / O device 11 for connecting to a reader / writer device 20, a CPU 12, a RAM 13,
The ROM 14 and the EEPROM 15 are built in, and the space between the IC card 10 and the reader / writer device 20 is
They are connected by I / O lines. I / O device 11
Has a function of transmitting and receiving data to and from the reader / writer device 20. The CPU 12 receives a command given from the reader / writer device 20 via the I / O device 11,
Do this. Of the three types of memory, the RAM 13 is a volatile memory and is used as a work area of the CPU 12. The ROM 14 is a fixed memory that cannot be rewritten, and records various program routines necessary for operating the CPU 12. A program routine for checking the format of an instruction given from the reader / writer device 20 is also recorded in the ROM 14. The EEPROM 15 is a non-volatile memory that can be rewritten at any time.
Various information (file directory, user data, and the like) necessary when 0 is used for a specific purpose is recorded.

From the reader / writer device 20 to the IC card 10
Each of the various instructions given to has a predetermined format. For example, a “file creation instruction” for creating a new file in the EEPROM 15 is:
It is described in a format as shown in FIG. According to this format, the command is divided into a command header portion and a command data field portion. The command header portion includes a code indicating that the command is a “file creation command”, various parameters, and a total data length. Are recorded in the command data field part, the total file capacity, record length, file structure, security attributes,
File definition information that defines a file name length, a file name, and the like is recorded. Here, for example, a character string corresponding to the name of this file is recorded in the file name area, and the length L of the character string of this file name is recorded in the file name length area. At this time, if the length L of the character string of the file name does not match the length recorded in the file name length, the “file creation instruction” cannot be executed correctly. Therefore, it is necessary to check the format of this instruction before executing this instruction. In addition, depending on the instruction, for example, "whether an unused bit is 1" or "whether or not it conforms to the ISO standard format" is checked.

In a conventional IC card, a program for checking the format of all instructions is stored in the ROM 14. Each time the CPU 12 receives a command from the reader / writer device 20, the CPU 12 executes the format check program in the ROM 14, confirms that the format is correct, and then executes the command. Therefore, the format check program occupies a considerable memory area in the ROM 14.

In the present invention, the reader / writer device
Commands given to the C card 10 are classified into two types. That is, an instruction to be used only until the IC card is issued,
The instruction is also used after the issuance of the C card. Instructions belonging to the former include a "file creation instruction", a "directory creation instruction", and a "key creation instruction".
These instructions are necessary to issue an IC card, and are used only when the IC card is in the issuer's hand. When the IC card is issued and passed to the general user, these instructions are not used. On the other hand, the commands belonging to the latter include a "data read command", a "data additional command", a "data rewrite command", a "key collation command", and the like. These instructions are necessary to use the IC card, and are mainly used in a state where the IC card is in the hands of a general user.

As described above, the reliability of the reader / writer connected to the IC card differs greatly before and after the issuing process. For example, in the case of an IC card used for bank deposit transactions, the relationship between the bank is the issuer and the depositor is the user, and after the bank issues the transaction, the IC card is handed over to the depositor. Become. This depositor is an unspecified number of ordinary citizens, and there is a risk that the IC card that has been handed to such a depositor may be exposed to various erroneous usage modes or unauthorized usage modes. For example, the IC card may be erroneously inserted into a completely unrelated terminal device, or may be intentionally inserted into a forged reader / writer device for unauthorized use. However, before the issuance process is performed, the IC card is handled by a bank or a specific company requested by the bank, and therefore it is considered natural that the IC card is inserted into an authorized reader / writer device. Therefore, if the command given before the issuance process is performed on the authorized reader / writer device side, there is no need to perform it again in the IC card.

Therefore, in the present invention, a format check is performed on the reader / writer device side for an instruction used only before the IC card issuance processing, and an instruction used after the IC card is issued is checked in the IC card. It was made. Therefore, for example, an instruction that is used only before the IC card issuance processing and is not used after the issuance processing, such as a “file creation instruction” whose format is shown in FIG. If so, there is no need to perform a check in the IC card 10. Therefore, it is not necessary to record a format check program for the “file creation instruction” in the ROM 14. As a result, the program capacity recorded in the ROM 14 can be reduced.

In the present application, “format check on the reader / writer device side” does not necessarily mean that the check is performed in the main body of the reader / writer device 20.
This is used in a broad sense to include checking in various systems connected to the system. Also, in the present application,
The wording “at the time of issuance” or “after issuance” is a word intended for “issuing action” for each application given to the IC card, and the issuance action of two or more times for the physically same IC card is performed. It does not prevent it from being done. For example, consider a case in which an IC card that was initially used as a bank transaction card is reissued so that it can be used later as a credit transaction card. In this case, the credit company will issue the IC card issued by the bank again. Therefore,
Paying attention to the use as a "bank transaction card", the time when the bank issued the issue process is "when issued"
Focusing on the use as a “credit transaction card”, the point at which the issuance process is performed by the credit company is “issued”. As described above, the “at the time of issuance” is one physically identical I
It does not indicate an absolute point in time about the C card,
It is a relative point defined for each application.

[0017]

As described above, according to the method of checking the command format given to the IC card according to the present invention, the format check is performed on the reader / writer side for the command used only before the issuing process. It is possible to reduce the program capacity in the inside.

[Brief description of the drawings]

FIG. 1 shows a general IC card 10 connected to a reader / writer 2
It is a block diagram showing the state connected to 0.

FIG. 2 is a diagram showing an example of a format of a file creation command given to an IC card 10.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... IC card 11 ... I / O device 12 ... CPU 13 ... RAM 14 ... ROM 15 ... EEPROM 20 ... Reader / writer device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-88691 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G06K 19/073 G06K 17/00

Claims (2)

(57) [Claims] In a checking method for checking a format of an instruction given from a reader / writer device to an IC card, an instruction to be used only up to the time of issuance of an IC card is provided.
A method for checking an instruction format given to an IC card, wherein a check is performed on the reader / writer device side and a command used after the IC card is issued is checked in the IC card. 2. The check method according to claim 1, wherein the command for creating a directory and the command for defining a key are checked on a reader / writer device side, wherein a check of an instruction format given to an IC card is performed. Method.