JP2782908B2 - IC card - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an IC card in an IC card system, and more particularly, to data exchange with an external terminal device in accordance with a communication format in which a transmission data length is indicated by upper and lower 2 bytes. The present invention relates to an IC card having an improved memory efficiency by selecting a storage area in accordance with the data length in an IC card system that exchanges data.

<Conventional Technology> Conventionally, in an IC card system, data is exchanged based on a predetermined communication format in communication between a host computer (external terminal device) and an IC card.

FIG. 8 is a diagram showing the structure of a communication format used between the host computer and the IC card.

In this figure, reference numeral 1 denotes a communication format for a read response transmitted from the IC card to the host computer when reading the user data of the IC card. Reference numeral 2 denotes a communication format for a write request transmitted from an IC card from a host computer when writing user data.

Communication format 1 for read response is 1 byte COD3 for distinguishing read / write, and IC
1-byte STS4 indicating the status of the CPU of the card, and 2-byte data length display portion 5 indicating the data length of the user data
And user data 6 of variable length bytes.

On the other hand, communication format 2 for a write request
Is the above-mentioned COD3, 1-byte AID7 for specifying the ID number of the area shown below, and 2-byte record NO storage area 8 for specifying the record number in the file.
And the data length display portion 5 and user data 6 of variable length bytes.

In these communication formats 1 and 2, a portion 5 for indicating the data length of user data has two bytes of upper and lower bytes. Then, the data length of the user data transmitted in one communication is always displayed as 2-byte data. For example, even if the user data is less than 256 bytes, it is displayed as "0000" H to "00FF" H. "0100" H if 256 bytes or more
The data length is displayed as .about. "FFFF" H.

FIG. 9 is a diagram showing the hierarchical structure of the memory of the IC card.

In this figure, reference numeral 11 denotes various files storing related information in a lump. These files
11 has a plurality of areas 13 for each file 11. Each of these areas 13 has a plurality of memory formats 12 divided into record units.

The memory format 12 includes an area 14 for storing user data in a record, an area 15 indicating a data length added to the head of each record, and the like. The data length display area 15 is based on the data length display portion 5 (2 bytes) of the communication format described above.
It is composed of 2 bytes.

Further, 16 is a directory, and this directory 16
Manages file 11 in memory hierarchically,
The area 13 manages various information such as a record number and a record length (length of user data).

FIG. 10 to FIG. 12 are flowcharts showing a communication procedure with an external terminal device in the conventional IC card system.

First, the host computer transmits a read or write communication format to the IC card.

Upon receiving the communication format from the host computer (step S1), the IC card selects the area 13 specified by the AID 7 (S2).

Next, the record designated by the record NO is searched (S3), and the COD is searched to determine whether to execute the read process or the write process (S4).

Then, the reading process (S5) or the writing process (S5)
After performing step 6), determine whether the process was completed normally (S
7). If the processing is normally terminated (YES), the response is set to a normal status (S8), and then this response is transmitted to the host computer (S9), and this program is terminated.

On the other hand, if the termination is abnormal (NO in S7), after setting an abnormal status in the response (S10), this response is transmitted to the host computer (S9), and this program is terminated.

Next, the reading process will be described. First, the data length of the record is confirmed (S11), and user data corresponding to the data length is read (S12).

Then, it is determined whether the reading has been completed normally (S13). If the reading has been completed normally (YES), a predetermined communication format (indicated by 1 in FIG. 8) is created in, for example, a communication buffer (S14). ), Return to the main program.

On the other hand, if the reading ends abnormally (NO in S13),
Create an abnormal status (S15) and return to the main program.

Further, the writing process will be described. First, the data length of the transmission data is checked in a communication format (indicated by 2 in FIG. 8) once held in the communication buffer (S2).
1) The user data is written to a predetermined record (S22).

Then, it is determined whether or not the writing has been normally completed (S23). If the writing has been normally completed (YES), a predetermined communication format (a response format including a normal completion status STS) is created (S24). Return to the program.

On the other hand, if the writing ends abnormally (NO in S23),
Create an abnormal status (S25) and return to the main program.

<Problem to be Solved by the Invention> However, such a conventional IC card has the following problems.

That is, in the communication format for data transfer between the external terminal device and the IC card, the format (user data area and its data length) is used as it is in the IC card according to the number of bytes (2 bytes) of the data length display portion. (A format including a 2-byte data length display area indicating the above.) Data was stored in a predetermined record (one unit of memory).

Therefore, the data length display area has to be specified as a high-order and a low-order 2-byte configuration for the records of all the areas (see FIG. 9). For example,
User data having a length of up to 255 bytes is displayed in two bytes as "0000" H to "00FF" H, although one-byte display is possible.

Therefore, in the memory area of the IC card, an area for indicating the data length added to the head of each record must be all 2 bytes. As a result, especially ICs with small capacity memory (for example, 1K bytes)
In the card, as the data length display area is increased, the memory area for storing user data is reduced, and the entire memory area cannot be used effectively.

Therefore, an object of the present invention is to provide an IC card that can effectively use the memory area of the IC card.

<Means for Solving the Problems> According to the present invention, as shown in FIG. 1, a first area for adding a 2-byte data length display portion when storing user data having a length of 256 bytes or more is provided. 110, a second area 120 to which a 1-byte data length display portion is added when storing user data having a length of less than 256 bytes, and an attribute description section 13 storing identification codes for identifying these areas.
0, and a data length display portion for displaying the length of user data transmitted in one communication in two bytes between the IC card 100 having the data card and the transmitted user data. In an IC card communication system comprising: an external terminal device 200 that transmits and receives user data based on the communication format obtained, a read determination for searching the attribute description unit 130 to determine the identification code when reading data. Means 140, output means 150 for adding an upper byte to the data length display portion of the read data when the identification code is in the second area 120, and output from the external terminal device 200 A write determining unit 160 that identifies a data length display portion of the data and determines whether the data length of the transmitted data is 256 bytes or more or less than 256 bytes; If the data length is less than 56 bytes, the upper byte is deleted from the data length display portion and the second area 120
And a storage means 170 for storing the information in an IC card.

<Operation> In the IC card according to the present invention, when reading data, the identification code is determined, and the identification code is stored in the second area 12.
If the value is 0, the upper byte is added to the data length display portion of the read data and output.

On the other hand, at the time of writing, the data length display portion of the data transmitted from the external terminal device 200 is identified, and if the data length of the transmitted data is less than 256 bytes, the data length display portion is , The upper byte is deleted and stored in the second area 120.

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

 2 to 7 are views showing an embodiment of the present invention.

In FIG. 2, 21 is an IC card, and 22 is this IC card.
It is a CAD (external terminal device) that exchanges data with the card 21 according to a predetermined communication protocol.

That is, the power supply VCC, the clock signal Clk, the ground level GND, the reset signal R
ST is supplied. In addition, data is exchanged between these units via each communication buffer. As a communication format of the communication data in this case, for example, a format based on the ISO standard is known as in the related art. (See FIG. 8). That is, when data is transmitted from the IC card 21 to the CAD 22,
In each case of transmitting data to the user, a 2-byte data length display portion is added to the head of the user data having a predetermined length.

Here, in the case of the IC card 21, an MPU 31 for controlling and calculating data transfer and the like, and a memory (EEPRO) connected to the MPU 31 by an address bus and a data bus.
M) 32. Although not shown, the IC card 21 further includes a ROM for storing a basic program and the like in the MPU 31, a RAM for securing a work area for work, and the like.

The EEPROM 32 has, for example, a plurality of files specially provided for application programs and a directory for managing the files and the like.
A plurality of areas are formed in each of these files. Each of these areas is constituted by a plurality of records as shown in FIGS. One record is composed of a user data storage area RUD for storing user data of an arbitrary length, a data length display area RDL indicating the length of the stored user data, and other areas.

In this embodiment, a second area in which user data having a length of less than 256 bytes can be stored in a single record and a user data having a length of 256 bytes or more are stored in the area. The first that can be stored
And an area. Figure 3 shows the first area,
FIG. 4 shows the second area.

Also, as shown in these figures, the directory
DRY indicates the area attribute in a 1-byte configuration, and the least significant bit is “1” when the data length display portion of each record is 1 byte, and “0” when it is 2 bytes. Is stored. That is, “0” is stored for the record in the first area, and “1” is stored for the record in the second area.

In the IC card 21 according to the above configuration, data is exchanged with the external terminal device CAD22 as follows.

FIG. 5 to FIG. 7 are flowcharts showing a communication procedure with the external terminal device CAD in the IC card system of the present invention.

First, the CAD 22 transmits a transmission command specified in a communication format for reading or writing to the IC card 21.

Thereafter, when receiving the transmission command from the CAD 22 (S51), the IC card 21 selects the area specified by the AID of the communication format (S52).

Next, the record specified by the record number of the communication format is searched, and it is determined whether the upper byte of the record number is “00” H (S53).

If "00" H, the lower byte of record NO (Lo
The record specified by (w bytes) is searched (S54).

If it is not "00" H, the record specified by the upper and lower bytes (2 bytes) of the record NO is searched (S55).

The reason for determining only the upper byte first in step S53 is to increase the processing speed.

Next, it is determined whether to execute the read process or the write process by searching for the COD of the communication format (S56).

Then, the reading process (S57) or the writing process (S57)
After execution of (58), it is determined whether or not the processing has been completed normally (S59). If normal end (YES), a normal status is set in the response (S60), the response is transmitted to the CAD 22 (S61), and the program ends.

On the other hand, in the case of abnormal termination (NO in S59), an abnormal status is set in the response (S62), this response is transmitted to CAD22 (S61), and this program is terminated.

Next, the read processing subroutine (S57) will be described with reference to FIG.

First, the data length is confirmed, and user data corresponding to the data length is read (S71). Then, it is determined whether or not the reading has been completed normally (S72). If the reading has been completed normally (YES), the directory is accessed, and the area of the area in which the record specified by the record NO is stored is stored. The attribute is determined (S73).

If the result of this determination indicates that the area attribute indicates a record in the first area (YES), the data length display portion RD
The data of L is stored in the data length display portion of the communication format as it is (S74), and the process returns to the main program.

On the other hand, as a result of step S73, when the area attribute indicates the record of the second area (NO in S73), “00” is added to the upper byte so that the data of RDL becomes the lower byte.
H is added to indicate the data length to 2 bytes (S7
Five). Then, the data is stored in the data length display portion of the communication format (S74), and the process returns to the main program.

Also, as a result of step S72, if the reading is abnormally terminated (NO in S72), an abnormal status is created (S76),
Return to the main program.

 Further, a write processing subroutine will be described.

First, it is determined whether or not the upper byte of the data length is “00” H in the communication format in which the data length of the transmission data is temporarily stored in the communication buffer (FIG. 7, S81).

If the upper byte of the data length is “00” H (YES), it is determined whether the area attribute indicates the second area (S82). Then, when indicating the second area (YES), the upper byte “0” of the data length is set.
By deleting "0" H, only the lower byte, that is, the data length is set to 1 byte (S83).

Then, the data length is stored in the data length display portion of the communication format (S84), and after writing the data corresponding to the data length, the process returns to the main program.

On the other hand, if the result of determination in step S82 indicates the first area (NO), the data length as it is is stored in the data length display portion of the communication format (S84), and data for the data length is written. Later, return to the main program.

Further, as a result of the determination in step S81, it is determined whether or not the first area is indicated (S85).
ES), store the data length as it is in the data length display portion of the communication format (S84), write data for the data length, and then return to the main program.

On the other hand, if the result of determination in step S85 is that neither the first nor the second area is indicated (NO), an abnormal status is set and the process returns to the main program.

<Effects> As described above, in the IC card of the present invention, the memory of the IC card can be used effectively.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an IC card according to the present invention, FIG. 2 is a block diagram showing a schematic configuration of an IC card according to an embodiment of the present invention, and FIGS. Pertain
FIG. 5 is a conceptual diagram showing the configuration of the memory area of the IC card.
FIG. 7 is a flowchart showing a communication procedure with an external terminal device in the IC card system according to one embodiment,
FIG. 8 is a diagram showing a structure of a communication format used between an external terminal device and an IC card, FIG. 9 is a diagram showing a hierarchical structure of a memory of a conventional IC card, and FIGS. 9 is a flowchart showing a communication procedure with an external terminal device in a conventional IC card system. 100 IC card 110 First area 120 Second area 130 Attribute description section 140 Read determination means 150 Output means 160 Write determination means 170: storage means, 200: external terminal equipment.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G06K 19/00 G06F 3/08

Claims (1)

(57) [Claims] 1. A first area to which a 2-byte data length display portion is added when storing user data having a length of 256 bytes or more, and 1 when storing user data having a length of less than 256 bytes. An IC card having a second area to which a byte data length display portion is added, an attribute description section storing identification codes for identifying these areas, and a single communication between the IC card and the IC card. An external terminal device for transmitting and receiving user data based on a communication format added to the user data to be transmitted, and a data length display portion for displaying the length of user data to be transmitted in 2 bytes. In the communication system, at the time of data reading, read determination means for searching the attribute description section to determine the identification code; and when the identification code is in the second area, read the data. Output means for adding a high-order byte to the display portion to output the data length of the data; and identifying the data length display portion of the data transmitted from the external terminal device to determine the data length of the transmitted data. Determination means for determining whether the data length is 256 bytes or more and less than 256 bytes, and when the transmission data is less than 256 bytes, deletes the upper byte from the data length display portion and stores it in the second area And an IC card.