JP2008016050A - Ic card - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an IC card reducing or increasing capacity of a file while maintaining security. <P>SOLUTION: The IC card having a memory storing one or more files has a capacity changing means for reducing or increasing the capacity of the file selected by specific capacity specified from the outside. The file has a free space storage part which stores its own free space, the capacity changing means has a master file change restriction means for changing the content of the free space storage part of a master file containing files based on the specific capacity and not permitting reduction of the capacity of the selected file by the capacity changing means when a value obtained by subtracting the specific capacity from the capacity of the selected file becomes less than the total capacity of the size of the files contained in the selected file when the capacity changing means reduces the capacity of the file. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an IC card capable of reducing or changing the capacity of a file stored in a memory by an external command.

  FIG. 11 is a block diagram showing a configuration of a conventional IC card and a connection relationship between the IC card and a reader / writer device. A conventional IC card 10 normally includes an I / O interface 11, a CPU 12, a ROM 13, a RAM 14, and an EEPROM 15. The I / O interface 11 is an input / output circuit for transmitting and receiving data, and the CPU 12 communicates with the reader / writer device 20 via the I / O interface 11. A program to be executed by the CPU 12 is stored in the ROM 13, and the CPU 12 controls the IC card 10 based on this program. The RAM 14 is a memory used as a work area when the CPU 12 performs such overall control. On the other hand, the EEPROM 15 is a memory for storing original data to be recorded on the IC card 10.

  FIG. 12 is a diagram showing a file structure in the EEPROM 15 shown in FIG. In the present embodiment, three types of files form a hierarchical structure. The three types of files are MF (Master File), DF (Dedicated File), and EF (Elementary File). MF is a file of the entire data memory. The MF is a file for storing data common to each application (service). For example, information such as the name, address, and telephone number of the owner of the IC card 10 is recorded. The DF is a dedicated file, and the DF is set for each application. The EF is a basic file, and there are two types: IEF for storing data to be interpreted and executed when the CPU manages and controls the IC card, and WEF for storing data used in the application.

  The MF, DF, and EF form a hierarchical structure shown in FIG. The MF is the root of the hierarchical structure, and the DF or EF is placed under the MF. In the example of FIG. 12A, the MF arranges DF1 and WEF1 under its control, and is a parent file of DF1 and WEF1. DF is a file in which MF can be positioned as a parent file, and at the same time, other DFs or EFs can be placed under the MF and become their parent file. On the other hand, EF is a file that cannot be a parent file of another file.

  FIG. 13 is a diagram showing an example of a file storage image in the EEPROM 15. In FIG. 13, the absolute address of the memory increases from the upper left to the lower right. Further, the horizontal width corresponds to 32 bits. In the present specification, the one having a larger absolute address is called an upper address. In the example shown in FIG. 13, the file directories are all composed of 32 bits, and are arranged in order so that there is no empty area between the directories from the higher address. On the other hand, the file data storage areas are arranged in order from the lower address so that there is no free space between the areas.

  In the state shown in the figure, the directories are regularly arranged every 32 bytes. Therefore, when searching for a directory or the contents of a directory, it is sufficient to search for an address every 32 bytes, and it is possible to quickly search a directory even with a CPU having a relatively low processing capacity. . One WEF data storage area is always stored together in one continuous memory area. For example, the WEF1 data storage area shown in FIG. 14 is distributed and stored in two areas. Absent. This is a procedure for maximally effectively using the limited memory resources of the EEPROM 15. That is, as shown in FIG. 14, when one data storage area is distributed and stored in a plurality of areas, a file allocation table or the like for managing address information of each of the distributed areas is required. Memory is consumed. On the other hand, in the example of FIG. 13, only the address information for one data storage area needs to be managed in the directory, and the amount of memory consumption is minimized.

The various files are stored by the IC card issuer so as to form a predetermined hierarchical structure when the IC card is issued. That is, various DFs and EFs are already stored in the IC card when the card is issued, and the IC card owner selects and uses necessary ones from the various stored files.
Patent Document 1 discloses an IC card that can effectively use a memory for storing data.
JP-A-6-131517

  However, in the conventional IC card described above, the IC card issuer stores various files regardless of the IC card owner. Moreover, in order to increase the value of the IC card, the IC card issuer may wish to store a large number of files corresponding to different applications and make the IC card usable for multiple purposes. However, the IC card owners do not always use all the provided applications because their lifestyles are different. For this reason, some owners frequently use some of the stored files, but not others at all. In such a case, there is a problem that a file that is frequently used is insufficient in capacity, but a memory that is not used is not used and is wasted.

  The above problem can be solved by deleting each file once, restoring each file to an appropriate size, and storing it again. However, in this case, the information recorded in each file is read out of the IC card and stored again, so that security that is one of the characteristics of the IC card cannot be secured. there were.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an IC card that can reduce or expand the file capacity while maintaining security.

In order to solve the above-mentioned problem, the invention according to claim 1 is the IC card having a memory capable of storing one or more files, and the specified capacity specified from the outside is selected by an external command. Capacity changing means for reducing or expanding the capacity of the file, the file has a free capacity storage unit for storing its own free capacity, and the capacity changing means is a parent file having the file under it. A value obtained by subtracting the designated capacity from the capacity of the selected file when the content of the free capacity storage unit is changed based on the designated capacity and the capacity changing unit reduces the capacity of the file. but if the selected file is smaller than the total volume of the size of the file that Yusuke under the size of the file that the capacity changing means is the selected An IC card and having a parent file changes limiting means does not allow to reduce.
According to a second aspect of the present invention, in the IC card according to the first aspect of the present invention, the IC card includes a moving unit that moves a data area of the file, and the directory area of the file is unused from one end of the memory. The file data area is stored in order so that there is no unused area from the other end of the memory, and the capacity changing means is selected. If the file is a file having a data area, the data area is reduced or enlarged by the specified capacity, and the moving means is on one end side of the memory from the data area reduced by the capacity changing means. The other data area is moved to the other end side of the memory by the specified capacity, or the capacity When the other data area exists on one end side of the memory from the data area to be expanded by the further means, the other data area is transferred to the one end side of the memory by the specified capacity. The IC card is characterized by being moved.

The present invention has the following effects.
(1) It is possible to change the capacity of the selected file while maintaining security.
(2) It is possible to prevent the information in the file from being lost by misidentifying the capacity of valid information included in the file and reducing the capacity of the file below the capacity.

(3) The file capacity is expanded beyond the area managed by the parent file, and as a result, a situation in which information held by another file is lost is prevented.
(4) Even if the file capacity is reduced or expanded, the free capacity of the parent file is accurately managed.

(5) As a result of reducing the capacity of the file, it is possible to prevent a situation in which information held by the file under the file is lost.
(6) Even if the data area of the file is reduced, a free area does not occur between the data areas. Further, even if the data area is enlarged, information held in other data areas is not lost, and a free area does not occur between the data areas. That is, it is possible to reduce or expand the data area while using the memory to the maximum extent and without losing information.

(7) Since the moving means moves the data area existing up to the position specified based on the information stored in the final data position storage means, the inconvenience of moving the data in the area where the data portion of the file is not stored. Is avoided.
(8) Since the capacity changing unit changes the contents of the position information storage unit based on the specified capacity, the contents of the position storage unit are maintained appropriately even after the data area is reduced or enlarged.
(9) Since the moving means changes the contents of the position information storage unit based on the designated capacity, the contents of the position information storage unit are maintained appropriately even after the data area is moved.

(10) In a variable-length record structure file, the address information of each record stored in the data area is changed based on the specified capacity, so that the data area is reduced, enlarged, or moved. It has a proper value afterwards.

(11) In a variable-length record structure file, when the address information is changed, the error detection code stored in the data area is also changed based on the changed address information. Even after being expanded or moved, the error detection code has a proper value.

  Hereinafter, an embodiment according to the present invention will be described in more detail with reference to the drawings. This embodiment is the same as the conventional IC card in hardware configuration, but differs from the conventional IC card in that it has a function of processing a CHANGE-SIZE command for changing the file size of the current file.

  FIG. 1 is a diagram showing a CHANGE-SIZE command APDU. In the CHANGE-SIZE command, in the parameter P1, whether the file whose size (capacity) is to be changed is the currently selected DF (hereinafter referred to as “current DF”) or EF (hereinafter referred to as “current EF”). specify. Further, the size to be changed is designated in the data field (DATA).

  FIG. 2 is a flowchart showing the operation of the IC card 10 that processes the CHANGE-SIZE command. If there is a “CHANGE-SIZE” command from the reader / writer device 20, the CPU 12 performs a pre-execution check (S701), and if there is an error, sends a message to that effect (S703). The file size is changed (S704), and when the command ends normally (S705), a message to that effect is transmitted (S708), and the command is ended.

  Next, the change of the file size in S704 will be described in more detail. In this embodiment, there are two types of files whose file size can be changed: DF / WEF. The size change supports both increase and decrease. Also, the DF size cannot be changed without specifying the capacity (the number of management pages FFh). The DF without capacity designation refers to a DF in which the capacity of the area managed by the DF is not defined and the file capacity can be expanded within the range of the free capacity of the parent file. In other words, a DF without capacity specification is a capacity parent-dependent file whose free capacity always matches the free capacity of the parent file. In a DF without capacity specification, the number of management pages is set to “FFh”. The management page number is a variable stored in the directory of the file, and indicates the capacity managed by the file.

The error check is performed for the following items.
1) The file to be resized is not MF / IEF. This is determined by referring to the directory of the file specified by the address of the current EF or current DF.
2) The free space of CRT-AP, CRT-DP, and MF directory must be consistent. This is determined by comparing the free space of the EEPROM 15 recorded in the MF directory with the difference between CRT-AP and CRT-DP. CRT-AP is a pointer that points to the start address of an area that can store a new data storage area, and CRT-DP is a pointer that points to the start address of an area where a new directory can be stored. is there.

3) There is a CRC for all entries in the directory table. This is performed using a CRC code included in each file directory.
4) All record format WEF CRCs are present. The CHANGE-SIZE command may reduce the file size. In this case, in order to prevent a situation where information already stored is deleted by mistake, it is necessary to confirm a record in which information is already stored in advance. However, if the record is destroyed for some reason, the above confirmation cannot be performed accurately. Therefore, it is confirmed in advance whether the record is maintained in an appropriate state.

5) There must be a CRC for the entire transparent WEF file. The reason for this check is the same as in 4) above. If the transparent file does not have a CRC check code, this check item is omitted.
6) When the file size increases, the size increase must be within the number of free pages in the area management DF. In this embodiment, one page is 32 bytes.
7) When the size of a DF is reduced, the size of all files under the DF must not be less than the total number of pages. DF can place one or more other files under it. In this case, if the DF is reduced below the total capacity of the subordinate files, the stored information may be erased.

8) The file size should not be smaller than the write append pointer when reducing the size of WEF (other than circular sequential organization).
9) In the case of size reduction of WEF (circular sequential file), it must not be a rotated file. The above 8) and 9) are measures for preventing a situation where information already stored is lost by mistake. The error check is performed before the EEPROM 15 is updated.

  Next, the area management DF is specified, and after the file size is changed, the free capacity of the management area DF is changed. The method for specifying the area management DF is as follows. Check the number of management pages of the parent DF of the file to be resized. If the number of management pages of the parent DF is FFh, the DF up one level is checked. If the number of management pages of all the parent DFs of the file to be resized is FFh, the MF is set as the area management DF.

FIG. 3 is a diagram for explaining the DF size change. Since the DF has no data storage area, only the directory is rewritten. Note that the DF size cannot be changed without specifying the capacity (the number of management pages FFh). FIG. 3A shows the case of size reduction.
# 1: First, it is confirmed that the number of DF reduction pages is equal to or less than the number of DF empty pages.
# 2: Decrease the number of management pages and the number of empty pages of DF.
# 3: The number of empty pages of the area management DF is added by the amount subtracted at # 1 :.

FIG. 3B shows the case of size increase.
# 1: First, the number of empty pages in the area management DF is subtracted by the increment of the size change DF.
# 2: The number of management pages and the number of empty pages of the size change DF are added by the increment of the size change DF.

  Next, WEF size change will be described. Since the WEF has a data storage area, it rewrites data in the directory and moves data in the data storage area. In addition, in order to move the data area, the contents of the directory of the moved file are rewritten.

[For size reduction] First, the size-change file is changed.
# 1: When the WEF to be reduced has a variable length, <address table pointer movement processing> described later is executed.
# 2: The number of bytes in the management area of the WEF-DIR to be reduced, the writable last address, and the address table pointer are rewritten to values obtained by subtracting the reduced amount.

FIG. 4 is a diagram for explaining rewriting of data in a file (packing reduced bytes).
# 1: The DIR address of the file to be reduced is set as a target.
# 2: 32 is subtracted from the target address.
# 3: End when the target address is the same as the CRT-DP.
# 4: When the target DIR is other than WEF, return to '# 2:'.
# 5: The data portion of the target DIR is moved by the reduced byte.
# 6: Return to '# 2:'.

Next, the content correction process of the moved WEF-DIR will be described.
# 1: The DIR address of the file to be reduced is set as a target.
# 2: Subtract 32 from the target address.
# 3: End when the target address is the same as the CRT-DP.
# 4: Return to '# 2:' when the target DIR is other than WEF.
# 5: Rewrite the number of bytes in the DIR management area, the writable final address, the address table pointer, and the WEF area start address by subtracting the reduced amount.
# 6: Return to '# 2:'.

FIG. 5 is a diagram for explaining the FFh clear of the unnecessary portion that has occurred as a result of moving the data portion.
# 1: An address obtained by subtracting the reduced amount from the CRT-AP is obtained.
# 2: FFh is cleared by the deleted data (capacity obtained by reducing the file) starting from this address.

FIG. 6 is a diagram for explaining the change of the CRT-AP.
# 1: Rewrite CRT-AP to a value obtained by subtracting the original value from the deleted value (capacity obtained by reducing the file size).

The rewriting of the WEF linear variable length “address table pointer” and CRC will be described.
# 1: The WEF-DIR to be reduced is set as a check DIR.
# 2: Subtract 32 from the check DIR.
# 3: End when the check DIR is the same as the CRT-DP.
# 4: When the check DIR is other than “WEF linear variable length”, return to “# 2:”.
# 5: The reduced byte is set as the “post-movement differential address”, and # 3 and subsequent steps of <address table pointer correction processing> to be described later are executed.
# 6: <Address table pointer CRC correction processing> described later is executed.
# 7: Return to '# 2:'.

Here, the rewriting operation of the WEF linear variable length “address table pointer” and CRC will be described.
# 1: 7F80h is set as the check DIR. In the example shown in FIG. 13, 7F80h is the address of the transport IEF directory, and the DF and EF directories under the MF are stored at addresses lower than this address.
# 2: Subtract 32 from the check DIR.
# 3: End when the check DIR is the same as the CRT-DP.
# 4: When the check DIR is other than “WEF linear variable length”, the process returns to “# 2:”.
# 5: <Address table pointer correction processing> is executed.
# 6: <Address table pointer CRC correction process> is executed.
# 7: Return to '# 2:'.

Next, <address table pointer correction process> will be described.
# 1: The content indicated by the WEF data area start address + the number of management area bytes−2 is acquired as the pre-movement WEF head address.
# 2: The value obtained by the WEF head address before movement−WEF erase size is stored as “differential address after movement”.
# 3: The address table pointer +1 is stored in the RAM 14 as a modified address.
# 4: The current number of records is saved, and when it is 0, the process is terminated.
# 5: The page including the correction address is read and held as page data.
# 6: The remainder obtained by dividing the correction address by 32 is held as 'page position'.
# 7: 2 bytes are read from the corrected address.
# 8: After the read data is moved, the differential address is held as correction data.
# 9: The correction data upper rank is set to the “page position” of the page data.
# 10: 1 is added to “page position”. When 32, one page is written back, “page position” is cleared to 0, and the next page is read.
# 11: The lower part of the correction data is set to the “page position” of the page data.
# 12: “1” is added to “page position”. When 32, one page is written back, and “page position” is cleared to zero.
# 13: 1 is subtracted from the current number of records, and when it is 0, the process is terminated.

Next, <address table pointer CRC correction process> will be described.
# 1: Holds the last address of the file and obtains the number of registered records.
# 2: When the number of registered records is 0, the process is terminated.
# 3: 2 is subtracted by the held address.
# 4: CRC check is executed and the execution result is held.
# 5: The record registration count is decremented by 1.
# 6: Return to '# 2:'.

[In the case of size enlargement] FIG. 7 is a diagram for explaining data rewriting of a file (expanding an enlarged byte).
# 1: Set CRT-DP as a target.
# 2: 32 is added to the target address.
# 3: End when the target address is the same address as the DIR for file expansion.
# 4: Return to '# 2:' when the target DIR is other than WEF.
# 5: Move the data portion of the target DIR to the “address upper direction” by the enlarged bytes.
# 6: Return to '# 2:'.

The content correction process of the moved WEF-DIR is as follows.
# 1: Set the DIR address of the file to be enlarged as a target.
# 2: Subtract 32 from the target address.
# 3: End when the target address is the same as the CRT-DP.
# 4: Return to '# 2:' when the target DIR is other than WEF.
# 5: The number of bytes in the DIR management area, the last writable address, the address table pointer, and the WEF area start address are rewritten to the added value.
# 6: Return to '# 2:'.

FIG. 8 is a diagram for explaining the change of the CRT-AP.
# 1: Rewrite to the value added by the amount enlarged from CRT-AP.

FIG. 9 is a diagram for explaining the content change of the storage area of the size change file.
# 1: <Address table pointer movement processing> is executed when the WEF to be enlarged has a variable length. When the WEF to be expanded is other than the variable length, FFh is written starting with the WEF-DIR WEF start address to be expanded + the number of bytes in the management area. When the WEF to be enlarged is other than the variable length, # 2: the number of bytes in the management area of the WEF-DIR to be enlarged, the writable final address, and the address table pointer are rewritten to the added value.

Next, rewriting of the WEF linear variable length “address table pointer” and CRC will be described.
# 1: Set as DIR for WEF-DIR check to be enlarged.
# 2: Subtract 32 from the check DIR.
# 3: End when the check DIR is the same as the CRT-DP.
# 4: When the check DIR is other than “WEF linear variable length”, return to “# 2:”.
# 5: As the “differential address after movement”, set the bit after reversing the expanded byte and adding 1 (because the file has been moved to the upper direction), and execute <3: Address table pointer correction processing> and subsequent steps To do.
# 6: <Address table pointer CRC correction process> is executed.
# 7: Return to '# 2:'.

  Here, the case where the WEF is a rotated circulation sequential organization file will be described. In order to maintain the record storage order, the following processing is performed when the size is increased. In the reordering unnecessary check, when the address indicated by the write append pointer exceeds the file end before the increase in size, the rotated flag is deleted and the process ends.

FIG. 10 is a flowchart showing the data rearrangement process. The data rearrangement process is performed according to the following procedure.
S901: The number of records up to the write append pointer is calculated, and the value is substituted into variable A.
S902: The operation start record is a record of physical number A.
S903: Variables X and Y are prepared.
S904: Substitute A into the variable X.
S905: The function Func is calculated based on the variable X, and the result is substituted into the variable Y. The processing content of the function Func will be described later.
S906: The physical record A and the physical record Y are exchanged.
S907: Substitute variable Y for variable X.
S908: It is determined whether or not the above processing has been performed for the number of records. When the processing has not been performed for the number of records, the process returns to S905, and when the processing has been performed for the number of records, the processing ends.

Next, the calculation contents of the function Func in S905 will be described.
S9051: It is determined whether or not the variable A is equal to or greater than X. If it is equal to or greater than the above, the process of S9052 is performed. If not, the process of S9053 is performed.
S9052: The variable X and the total number of records are added to the variable Y, and the variable A is further subtracted.
S9053: Variable X is added to variable Y, and variable A is further subtracted.

<Address table pointer movement processing> is as follows. The source, destination address, and number of bytes to move are acquired. When (Move source) <(Move destination), move from the last data.
# 1: The movement destination address + the number of movement bytes−1 is the movement destination address, and the movement source address + the number of movement bytes−1 is the movement source address.
# 2: Read the page containing the destination address.
# 3: The destination address / 32 is set as a counter.
# 4: Set the contents of the source address to the counter of the read data.
# 5: When the counter is not 0, proceed to '# 8:'.
# 6: The set page data is written back to the EEPROM 15.
# 7: Read the previous page and set 32 to the counter.
# 8: Subtract 1 from the counter, source address, and number of bytes moved.
# 9: When the number of moving bytes is 0, the set page data is written back to the EEPROM 15, and the process is terminated.
# 10: Return to '# 4:'.

When (Move source)> (Move destination), move from the top data.
# 1: Read the page containing the destination address.
# 2: The destination address / 32 is set as a counter.
# 3: The content of the source address is set at the counter of the read data.
# 4: When the counter is not 31, proceed to '# 7:'.
# 5: The set page data is written back to the EEPROM 15.
# 6: After page 1, read 0 and set counter to 0.
# 7: 1 is added to the counter, the source address, and the number of bytes moved.
# 8: Subtract 1 from the number of moving bytes.
# 9: When the number of moving bytes is 0, the set page data is written back to the EEPROM 15, and the process is terminated.
# 10: Return to '# 3:'.

It is a figure which shows the command APDU of CHANGE-SIZE. It is a flowchart which shows operation | movement of the IC card 10 which processes a CHANGE-SIZE command. It is a figure explaining size change of DF. It is explanatory drawing about rewriting of the data part of a file (packing for a reduction byte). It is a figure explaining unnecessary part FFh clear. It is a figure explaining change of CRT-AP. It is explanatory drawing about the data partial rewriting (expanding by an expansion byte) of a file. It is a figure explaining change of CRT-AP. It is explanatory drawing about the content change of the storage area of a size change file. It is a flowchart which shows a data rearrangement process. It is a block diagram which shows the structure of the conventional IC card, and the connection relationship between the IC card and a reader / writer device. 2 is a diagram showing a file configuration in an EEPROM 15. FIG. It is a figure which shows an example of the file storage image in EEPROM. It is an example of the file storage image in EEPROM, Comprising: It is a figure which shows a different thing from what is shown in FIG.

Explanation of symbols

11 I / O interface 12 CPU
13 ROM
14 RAM
15 EEPROM
20 Reader / writer device

Claims (2)

In an IC card having a memory capable of storing one or more files,
A capacity changing means for reducing or enlarging the capacity of the file selected by the designated capacity designated from outside by an external command;
The file has a free capacity storage unit for storing its own free capacity,
The capacity changing means changes the content of the free capacity storage unit of the parent file under the file based on the specified capacity,
When said capacity changing means to reduce the capacity of the file, the capacity of the file that is the selected value obtained by subtracting the designated capacity is the size of the files that the selected file is Yusuke under An IC card comprising: a parent file change restricting means that does not permit the capacity changing means to reduce the capacity of the selected file when the total capacity is smaller than the total capacity. In the IC card according to claim 1 ,
Moving means for moving the data area of the file;
The directory area of the file is stored in order so that there is no unused area from one end of the memory, and the data area of the file has no unused area from the other end of the memory. Are stored in order as
When the selected file is a file having a data area, the capacity changing unit reduces or enlarges the data area by the specified capacity,
The moving means has the specified capacity to the other end side of the memory when the other data area exists on one end side of the memory from the data area reduced by the capacity changing means. If another data area exists on the one end side of the memory from the data area to be moved or expanded by the capacity changing means, the one end side of the memory And moving the other data area by the specified capacity.

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